Surveillance of Invasive Bacterial Disease in Alaska, 2012 

Arctic Investigations Program 

National Center for Emerging & Zoonotic Infectious Diseases 

Centers for Disease Control and Prevention 

4055 Tudor Centre Dr. 

Anchorage, AK 99508 

(907) 729-3400 

ncidaip@cdc.gov
Surveillance of Invasive Bacterial Disease in Alaska, 2012 2 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 3 

Alaska Statewide Invasive Bacterial Disease 

Table of Contents 

 Page 

Summary 4 

Introduction 5 

Invasive Pneumococcal Disease 6 

Invasive Haemophilus influenzae 16 

 

Invasive Neisseria meningitidis 21 

Invasive Group A Streptococcus 22 

Invasive Group B Streptococcus 29 

References 34 

Appendix 36 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 4 

Summary 

The Centers for Disease Control and Prevention's Arctic Investigations Program (AIP) in Anchorage, 

Alaska, maintains a statewide surveillance system for invasive diseases caused by Streptococcus 

pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and groups A and B streptococci. 

Laboratories throughout the state are requested to send to AIP any isolates of these organisms recovered 

from a blood culture, CSF, or other normally sterile site in an Alaska resident. Isolate identification is 

confirmed and, when appropriate, serotyped and tested for antimicrobial susceptibility. The objectives 

of this system are to provide information on disease rates within the state, monitor the emergence of 

antimicrobial resistance, and to monitor the effectiveness of implemented vaccine programs, such as the 

23-valent pneumococcal polysaccharide vaccine, the pneumococcal conjugate vaccine and Haemophilus 

influenzae type b vaccines. 

Figure 1: Invasive Bacterial Disease Surveillance Regions – Alaska, 2012 

In 2012, the total numbers of cases of invasive disease caused by these organisms reported to AIP were

130 S. pneumoniae, 15 H. influenzae, 2 N. meningitidis, 48 group A streptococci (GAS) and 33 group B 

streptococci (GBS). Alaska Native people had higher rates of disease overall than non-Native people for 

Arctic Slope

Interior

Kotzebue

Norton Sound

YK Delta

Bristol Bay

Anchorage

Southeast
Surveillance of Invasive Bacterial Disease in Alaska, 2012 5 

all surveillance organisms. Rates of invasive pneumococcal disease were highest in the YK Delta and 

Kotzebue regions. Rates for each organism by region are presented in the following table. 

Table 1: Surveillance Organisms Reported by Region – Alaska, 2012 

Region 

S. pneumoniae 

n (rate*) 

H. influenzae 

n (rate*) 

N. meningitidis 

n (rate*) 

GAS 

n (rate*) 

GBS 

n (rate*) 

Anchorage 58 (12) 6 (1.2) 1 (0.2) 28 (5.8) 20 (4.1)

Arctic Slope 4 (45.9) 0 (0) 0 (0) 0 (0) 1 (11.5) 

Bristol Bay 2 (27.4) 1 (13.7) 0 (0) 1 (13.7) 0 (0) 

Interior 21 (18.4) 1 ( 0.9) 1 (0.9) 7 (6.1) 5 (4.4)

Kotzebue 5 (59.7) 0 (0) 0 (0) 3 (35.8) 1 (11.9) 

Norton Sound 3 (30.4) 0 (0) 0 (0) 1 (10.1) 0 (0) 

Southeast 12 (16.1) 2 (2.7) 0 (0) 3 (4) 3 (4) 

YK Delta 25 (98.2) 5 (19.6) 0 (0) 5 (19.6) 3 (11.8)

Total 130 (17.8) 15 (2.1) 2 (0.3) 48 (6.6) 33 (4.5)

*Cases per 100,000 population 

Introduction 

AIP conducts statewide surveillance of invasive Streptococcus pneumoniae, Haemophilus influenzae, 

Neisseria meningitidis, and groups A and B Streptococcus. This program is part of a passive, 

laboratory-based surveillance system in which laboratories from all hospitals throughout the state are

encouraged to participate. The population included in the AIP surveillance is the State of Alaska, which 

totaled 731,827 persons in 2012 [1]. Case detection occurs year-round as participating laboratories send 

isolates recovered from sterile sites to the AIP laboratory in Anchorage; materials and forms for isolate 

shipment and data collection are provided to each laboratory by AIP. Demographic and clinical 

information on the cases are collected from a review of medical records. At year-end, AIP asks that 

each laboratory review their records and provide information on any cases that may have been 

overlooked. In 2012, 23 laboratories in Alaska participated in the invasive disease surveillance system, 

either by sending isolates to the AIP laboratory throughout the year, conducting year-end record 

reviews, or both. Beginning in January, 2007, invasive S. pneumoniae, GAS and GBS became 

reportable conditions to the State of Alaska Division of Public Health (DPH). Reports of cases of 

disease caused by these organisms, along with cases of invasive H. influenzae and N. meningitidis which 

were previously reportable, are shared between AIP and DPH. 

AIP defines a case of invasive S. pneumoniae, H. influenzae, N. meningitidis, GAS or GBS as an isolate 

of the bacteria from a normally sterile site, including blood, cerebrospinal fluid, pleural fluid, peritoneal 

fluid or joint fluid that has been taken from a resident of Alaska. In addition, for GAS, isolates are 

requested from deep tissue infections such as might be collected from surgical debridement of cases of

necrotizing fasciitis.
Surveillance of Invasive Bacterial Disease in Alaska, 2012 6 

Invasive Pneumococcal Disease 

Overall Incidence

A total of 123 pneumococcal isolates were received at AIP in 2012. An additional 2 cases were detected 

through year-end follow up with participating laboratories and 5 cases through shared surveillance with 

the State DPH for a total of 130 cases of invasive pneumococcal disease. The overall rate for invasive 

pneumococcal disease in 2012 was 17.8 cases per 100,000 persons per year. Alaska rates for 2012 were 

higher than the Active Bacterial Core Surveillance (ABCs) 2012 national projected rate of 10.1/100,000

[2]. ABCs is a surveillance system operated in 10 states which covers a population of up to 42 million 

persons. 

Seasonality

Invasive Streptococcus pneumoniae cases were identified in each month of 2012. The largest number of 

cases (n=17) was reported in October. 

Race 

In 2012, the state population was comprised of 19.5% Alaska Native people (Alaska Natives 142,435, 

non-Natives 589,392) [1]. Of all reported S. pneumoniae cases in 2012, 52% occurred among Alaska 

Native people for a total of 68 cases; the age-adjusted rate was 52.5/100,000 persons per year. Sixtytwo cases occurred among the non-Native population for an age-adjusted rate of 9.7/100,000 persons per

year. The rate ratio of age-adjusted rates of S. pneumoniae disease for the Alaska Native population 

compared with the non-Native population in 2012 was 5.4.

0

5

10

15

20

Number of Cases

Figure 2: Invasive Pneumococcal Disease, by 

Month of Culture - Alaska, 2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 7 

Table 2: Invasive Streptococcus pneumoniae Cases by Race – Alaska, 2012 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 68 (52) 52.5 62% 10 (14.9)‡

Non-Native† 62 (48)† 9.7 63% 7 (11.3) 

Total 130 62% 17 (13.1) 

*Cases per 100,000 per percent distribution of Alaska 2010 population 

†Includes 5 cases for which race was unknown 

‡Outcome unknown in 1 case 

Region 

The highest percentage (45%) of invasive pneumococcal disease cases occurred in the Anchorage area 

in 2012. Rates of disease, however, were highest in the Kotzebue region (59.7/100,000 persons per 

year) and the YK Delta (98.2/100,000 persons per year). 

Age

Cases occurred in all age groups in 2012 ranging from 1 month to 99.5 years with a median age of 57 

years. Overall, the highest rates of disease occurred in children less than two years old. 

 

When stratified by age and race, the highest rates of disease in 2012 occurred in Alaska Native children 

less than two years old (177.5/100,000 persons per year). 

0

20

40

60

80

100

120

0

20

40

60

80

Number of Cases

Rate per 100,000

Figure 3: Invasive Pneumococcal Disease, Cases 

& Rates by Region - Alaska, 2012

Cases

Rate
Surveillance of Invasive Bacterial Disease in Alaska, 2012 8 

Since the initiation of a pneumococcal 7-valent conjugate vaccine program in 2001, overall rates of 

invasive disease declined dramatically in children less than 2 years of age [3]. In 2008, the rate of

invasive pneumococcal disease in children less than 2 years declined to 65.6/100,000 which was the 

lowest rate observed in this age group since introduction of the 7-valent vaccine. Following introduction 

of a 13-valent conjugate vaccine in 2010, rates of disease observed in children less than 2 years old 

declined to 18/100,000 in 2011. In 2012, however, disease rates in this age group increased to 

60.3/100,000 due to disease caused by serotypes not included in the current vaccine. 

Although pneumococcal disease rates dropped initially in AK Native and non-Native children less than 

2 years of age after introduction of the 7-valent vaccine, the rates of disease in AK Native children less 

than 2 years trended upward from a low of 93.6/100,000 in 2001 to 335.9/100,000 in 2006. This 

increase in rates was due primarily to disease caused by serotypes not contained in the pneumococcal 

conjugate vaccine [4,5]. In 2009, rates of disease in AK Native children less than 2 years declined to 

87.1/100,000 which was the lowest rate since the introduction of the seven-valent pneumococcal 

vaccine. After introduction of the 13-valent vaccine in 2010, rates declined to 30.7/100,000 in 2011,

however, increased to 177.5/100,000 in 2012; 10 of 11 (91%) cases were caused by non-vaccine 

0

20

40

60

80

100

120

140

160

180

200

0

5

10

15

20

25

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Number of Cases

Age (yrs)

Figure 4: Invasive Pneumococcal Disease, Cases 

& Rates by Age Group & Race - Alaska, 2012

AK Native

(# cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)

0

20

40

60

80

100

120

140

160

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Age (yrs)

Figure 5: Invasive Pneumococcal Disease by Age 

Group - Alaska, 2003-2012

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 9 

serotypes. Rates of invasive disease in non-Native children less than 2 years declined during the same 

time period reaching 26.8/100,000 in 2005, and following an increase to 64.4/100,000 in 2007, declined

in 2008 to 6.2/100,000. In 2009, the rate of disease in non-Native children less than 2 years increased to 

60.3/100,000, but declined to 13/100,000 in 2012 with use of the 13-valent vaccine. 

Clinical Presentation

The primary clinical presentation was determined by a review of the discharge diagnoses in each 

patient’s individual medical record associated with the invasive bacterial illness. In cases with multiple 

discharge diagnoses, the most serious diagnosis related to the pneumococcal infection was recorded as 

the primary clinical presentation. Pneumonia with bacteremia was the most common primary clinical 

presentation in 2012 (70%) followed by bacteremia (14%). Twenty-six cases had a secondary 

pneumococcal-related diagnosis in 2012 - 13 pneumonia, 3, empyema, 2 endocarditis, 1 cellulitis, 1 

osteomyelitis and 6 unspecified presentations. 

0

100

200

300

400

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Age (yrs)

Figure 6: Invasive Pneumococcal Disease in 

Alaska Natives, by Age Group - Alaska, 2003-2012

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

0

100

200

300

400

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Age (yrs)

Figure 7: Invasive Pneumococcal Disease in NonNatives, by Age Group - Alaska, 2003-2012

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 10 

In 2012, blood was the most common source of a positive culture which was used to identify 120 (92%) 

of 130 cases. Cerebrospinal fluid was the positive site for 5 (4%) of cases; two cases were identified 

from pleural fluid and one each from joint and peritoneal fluid. One case was identified using PCR on

pleural fluid from a person pre-treated with antibiotics.

Mortality 

In 2012, the overall case fatality ratio for S. pneumoniae in Alaska was 13.1% (17 deaths out of 129 

cases for which outcomes were known). The case fatality ratio for AK Natives was slightly higher 

(14.9%, 10 deaths) than non-Natives (11.3%, 7 deaths). The largest number of deaths and the highest 

case fatality ratio occurred in the 19-54 age category (9 deaths) 24.3%. 

91

18 10 4 2 2 2 1

0

20

40

60

80

100

Number of Cases

Figure 8: Primary Clinical Presentations of 

Invasive Pneumococcal Disease - Alaska, 2012

*with bacteremia

0

5

10

15

20

25

30

0

1

2

3

4

5

6

7

8

9

10

<2 2-4 5-18 19-54 55-64 65+

Case Fatality Ratio (%)

Number of Deaths

Age (yrs)

Figure 9: Invasive Pneumococcal Deaths & Case 

Fatality Ratios by Age Group - Alaska, 2012

Deaths

CFR
Surveillance of Invasive Bacterial Disease in Alaska, 2012 11 

Serotype 

Serotyping of invasive pneumococcal isolates is performed at AIP using internationally standardized 

methods. Serotype identification is based on the organism’s polysaccharide capsule which is a principal 

virulence factor for pneumococci. This information provides a way to categorize organisms and to 

determine if the infection was due to a type that could be prevented by use of one of the available 

pneumococcal vaccines. Serotyping was performed on all of the S. pneumoniae cases for which an 

isolate was available. 

Table 3: Invasive Pneumococcal Serotype Distribution by Race and Age Group – Alaska, 2012 

 Alaska Native Non-Native 

Serotype Total n (%) <2 2-18 19-64 65+ <2 2-18 19-64 65+ 

03 12 (10) - 1 6 1 - - 4 - 

06A 1 (1) - 1 - - - - - - 

06C 4 (3) - - - - - - 2 2 

07C 1 (1) - - - - - - - 1 

07F 10 (8) - - 2 1 - - 5 2 

08 5 (4) - - 4 - - - 1 - 

09N 3 (2) - - - 1 - - 1 1 

10A 3 (2) - - - 1 - - 1 1 

11A 2 (2) - 1 - - - - 1 - 

12F 8 (7) 2 1 3 - - - 2 - 

15A 7 (6) 4 - 2 - - - 1 - 

15C 1 (1) - 1 - - - - - - 

16F 2 (2) - - 1 1 - - - - 

17F 1 (1) - - 1 - - - - - 

19A 8 (7) - 1 1 - 1 - 4 1 

19F 2 (2) 1 - - - - - - 1 

20 9 (7) - - 5 2 - 1 1 - 

21 1 (1) 1 - - - - - - - 

22A 1 (1) 1 - - - - - - - 

22F 12 (10) - - 2 1 1 1 4 3 

23A 5 (4) - - 1 1 - - 2 1 

23B 2 (2) - - - - - - 2 - 

31 6 (5) - - 4 - - - - 2 

33F 8 (7) 1 - - 2 - 2 2 1 

35B 4 (3) 1 - 1 - - - - 2 

35F 2 (2) - - 1 - - - 1 - 

38 2 (2) - - - - - - 2 - 

Total 122 11 6 34 11 2 4 36 18 

In 2012, the most common pneumococcal serotypes were 22F, (12 isolates, 10%), 3 (12 isolates, 10%) 

and 7F (10 isolates, 8%). From 1986 through 2001, serotype 14 was the most common invasive 

pneumococcal serotype ranging from 7.4% to 23.5% of isolates. Following introduction in 2001 of the 

pneumococcal conjugate vaccine which includes serotype 14, the proportion of serotype 14 isolates 

dropped to 1.5% of serotyped isolates in 2006 and the last case was in 2009. Disease caused by 

serotypes 7F and 19A, which are not included in the 7-valent conjugate vaccine, continually increased 

until the introduction of the 13-valent vaccine in 2010 which does include these two serotypes. 

Although cases caused by 7F and 19A continue to occur, they are no longer the most common serotypes 

and it is anticipated that the number of cases will continue to decline with the use of the vaccine. The 

majority (67%) of serotype 22F cases and serotype 3 cases (42%) occurred in the Anchorage area in 

2012. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 12 

Table 4: Invasive Pneumococcal Serotype Distribution by Region – Alaska, 2012 

Serotype 

Anchorage Arctic Slope Bristol Bay Interior Kotzebue Norton Sound Southeast YK Delta 

03 5 2 - 3 - - 2 - 

06A - - - - - - - 1 

06C 2 - - 2 - - - - 

07C - - - 1 - - - - 

07F 7 - - 1 - - 2 - 

08 1 - - - - 1 - 3 

09N 2 - - - 1 - - - 

10A 2 - - - - 1 - - 

11A 2 - - - - - - - 

12F - - - 2 - - - 6 

15A 1 - - - - - 2 4 

15C 1 - - - - - - - 

16F 1 - - - 1 - - - 

17F - 1 - - - - - - 

19A 4 - - 2 - 1 1 - 

19F 1 - - - - - - 1 

20 3 1 - 1 1 - 1 2 

21 - - - - - - - 1 

22A - - - - - - - 1 

22F 8 - - 1 - - 2 1 

23A 3 - - - - - - 2 

23B - - - 1 - - 1 - 

31 5 - - - 1 - - - 

33F 3 - - 4 - - - 1 

35B 2 - - - - - 1 1 

35F - - - 1 - - - 1 

38 1 - - 1 - - - - 

Unknown 4 - 2 1 1 - - - 

Total 58 4 2 21 5 3 12 25 

Vaccine Serotypes

In 2001, the pneumococcal conjugate vaccine (PCV7) was included in the Alaska childhood vaccination 

schedule. This vaccine provided protection against the 7 most common pneumococcal serotypes 

causing invasive disease among children (types 4, 6B, 9V, 14, 18C, 19F, 23F). In early 2010, a new 

pneumococcal conjugate vaccine (PCV13) was introduced into the Alaska childhood vaccination 

schedule. This vaccine provided protection against the 7 pneumococcal serotypes contained in the 

PCV7 vaccine plus six additional serotypes (1, 3, 5, 6A, 7F, 19A) that have caused invasive disease 

since the introduction of the PCV7 vaccine. The table below shows the proportion of invasive infections 

from 2012 that were due to serotypes found in the PCV13 vaccine. There were four cases of 

pneumococcal disease caused by serotypes contained in the PCV13 vaccine in children less than 5 years 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 13 

of age, the age group for which the vaccine is recommended. It is anticipated that the number of cases 

caused by these serotypes will decrease over time. 

Table 5: Proportion of Invasive Isolates Contained in the PCV13 Vaccine by Age Group and Race 

– Alaska, 2012 

Age (yrs) Alaska Native (%) Non-Native (%) Total (%) 

<2 1 (9%) of 11 1 (50%) of 2 2 (15%) of 13 

2-4 2 (67%) of 3 0 (0%) of 2 2 (40%) of 5 

5+ 12 (25%) of 48 17 (30%) of 56 29 (28%) of 104 

Total 15 (24%) of 62 18 (30%) of 60 33 (27%) of 122

For the year covered by this report, the 23-valent polysaccharide vaccine (Ps23V) was recommended in 

Alaska for all persons 65 years and older, and for persons over age 2 who are at higher risk for 

pneumococcal disease [5]. In 2012, for persons 65 years and older, 19 (66%) of 29 cases serotyped 

were potentially vaccine preventable invasive pneumococcal illnesses. 

Vaccine Failures 

In 2012, pneumococcal vaccine status was known for 112 (86%) of the 130 cases; 62 cases (55%) of 

cases with known vaccine status did receive a pneumococcal vaccine prior to illness and 50 cases (45%)

had no record of a pneumococcal vaccine. 

A PCV13 vaccine failure is defined as invasive pneumococcal disease caused by a serotype contained in 

the PCV13 vaccine in a child less than five years old who has had at least two doses of vaccine. There 

were three vaccine failures in 2012. All three children were less than three years old and presented with 

pneumonia; two of them presented with empyema. All three children were anemic. Serotypes of the 

cases were 19A (n=2) and 3 (n=1). 

Potentially Preventable Deaths

Overall, 35% of all pneumococcal-related mortality in 2012 was potentially preventable with the use of

the 23-valent polysaccharide vaccine in persons over 2 years old; 59% of deaths were due to disease 

caused by serotypes not contained in the 23-valent vaccine. 

Table 6: Potentially Vaccine Preventable Invasive Pneumococcal Deaths – Alaska, 2012 

Serotypes < 2 years 2-4 5-18 19-54 55-64 65+ Total 

PCV13 0 0 0 0 0 0 0 

Ps23V 0 0 0 3 (33%) 2 (40%) 1 (33%) 6 (35%) 

Non-Vaccine 0 0 0 5 (56%) 3 (60%) 2 (67%) 10 (59%) 

Unknown 0 0 0 1 (11%) 0 0 1 (6%) 

Total 0 0 0 9 5 3 17 

Six of the 17 deaths in 2012 from invasive S. pneumoniae occurred from serotypes contained within the 

Ps23V vaccine; one of the deaths was in an individual eligible for the vaccine. This death occurred in a 

vaccinated individual; time since vaccination was 2 years. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 14 

Table 7: Invasive Pneumococcal Disease, Serotypes of Fatal Cases – Alaska, 2012 

Serotype 

Deaths 

n (%) 

Serotype 

Frequency (n) 

03†* 1 (8%) 12 

06C 2 (50%) 4 

09N* 1 (33%) 3 

15A 1 (14%) 7 

16F 2 (100%) 2 

20* 2 (22%) 9 

22F* 2 (17%) 12 

23B 1 (50%) 2 

31 1 (17%) 6 

35B 1 (25%) 4 

35F 2 (100%) 2 

† Serotypes contained in the 13-valent conjugate vaccine 

*Serotypes contained in the 23-valent polysaccharide vaccine 

Associated Risk Factors

The presence of one or more associated risk factors was reported in 85% of invasive pneumococcal 

cases in 2012. Cigarette smoking was the most prevalent risk factor observed in adults followed by 

alcohol abuse and chronic lung disease. 

Table 8: Associated Medical Risk Factors in Invasive Pneumococcal Cases – Alaska, 2012* 

Medical Condition/Risk 

Factor 

Adult Cases (≥ 18 years) 

n=102, Cases (%) 

Cigarette smoking 46 (45%) 

Alcohol abuse 31 (30%) 

Chronic lung disease 30 (29%) 

Diabetes 18 (18%) 

Immunosuppressive treatment 3 (3%) 

Injection drug use 1 (1%) 

Asplenia 1 (1%) 

*More than one risk factor was identified in several cases 

Antibiotic Resistance

Susceptibility testing was performed on 121 isolates received in 2012. Results of the testing are 

presented in the following table. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 15 

Table 9: Antibiotic Resistance in Invasive Streptococcus pneumoniae Isolates – Alaska, 2012 

Antibiotic Susceptible Intermediate Resistant I + R Total Tested 

Penicillin 98 (81%) 0 (0%) 23 (19%) 23 (19%) 121 

TMP-sulfa 99 (82%) 12 (10%) 10 (8%) 22 (18%) 121 

Erythromycin 96 (79%) 0 (0%) 25 (21%) 25 (21%) 121 

Ceftriaxone 111 (92%) 6 (5%) 4 (3%) 10 (8%) 121

Tetracycline 107 (88%) 0 (0%) 14 (12%) 14 (12%) 121 

Chloramphenicol 121 (100%) 0 (0%) 0 (0%) 0 (0%) 121

Vancomycin 121 (100%) 0 (0%) 0 (0%) 0 (0%) 121 

Levofloxacin 121 (100%) 0 (0%) 0 (0%) 0 (0%) 121 

Clindamycin 108 (89%) 0 (0%) 13 (11%) 13 (11%) 121 

Cut points from the Minimum Inhibitory Concentration (MIC) Interpretive Standards were used to 

determine if an isolate was ‘susceptible’, ‘intermediate’, or ‘resistant’ to the antibiotic being tested [7]. 

The MIC Interpretive Standards definitions of ‘susceptible’, ‘intermediate’, and ‘resistant’ can be found 

in the Appendix. 

Serotypes found in the PCV7 and PCV13 vaccines are more likely to be non-susceptible to penicillin 

and erythromycin than non-vaccine serotypes. One potential benefit of the use of these vaccines was an 

anticipated decline in antibiotic resistance among circulating pneumococci. Following the initiation of 

the PCV7 vaccine in 2001, antibiotic resistance among invasive pneumococci dropped. During 2003, 

TMP-sulfa and penicillin resistance increased, however, following an increase in disease caused by 

serotype 19A. This serotype is included in the PCV13 vaccine; decreasing proportions of resistant 

isolates tested may be due to the introduction of the vaccine. 

0

5

10

15

20

25

30

35

Percent Resistant

Year

Figure 10: Trends in Antibiotic Resistance Among 

Invasive Pneumococcal Isolates - Alaska, 1992 - 2012

Penicillin

Erythro

TMP-Sulfa

Tet
Surveillance of Invasive Bacterial Disease in Alaska, 2012 16 

Invasive Haemophilus influenzae

Overall Incidence 

In 2012, there were 15 cases of invasive Haemophilus influenzae in Alaska, for a statewide rate of 

2/100,000 persons per year. This rate is slightly higher than the national projected rate of 1.67/100,000 

persons per year [8]. There was one death caused by H. influenzae in 2012 for a case fatality ratio of 

7%. 

Seasonality 

Cases of invasive H. influenzae occurred throughout 2012; however, due to the small number of cases, 

trends in seasonality cannot be determined. 

Region 

The highest rates of disease caused by invasive H. influenzae cases in 2012 were in YK Delta, 

19.6/100,000 (5 cases), and Bristol Bay, 13.7/100,000 (1 case). Although a large number of cases 

occurred in the Anchorage area (6 cases), the rate was much lower (1.2/100,000). 

0

1

2

3

4

5

Number of Cases

Month of Culture

Figure 11: Haemophilus influenzae Disease by 

Month of Culture - Alaska, 2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 17 

Race 

Table 10: Invasive Haemophilus influenzae Cases by Race – Alaska, 2012 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 10 (67%) 6.8 80% 1 (10%) 

Non-Native 5† (33%) 0.8 20% 0 (0%) 

Total 15 60% 1 (7%) 

*Cases per 100,000 per percent distribution of Alaska 2010 population 

†Includes two cases for which race is unknown

In 2012, 67% of the cases occurred in Alaska Natives. Age-adjusted rates were calculated for Alaska 

Natives and non-Natives. The age-adjusted rate ratio of H. influenzae disease for the Alaska Native 

population compared with the non-Native population in 2012 was 8.5. 

Age 

H. influenzae cases ranged in age from four months to 79 years of age in 2012 (median 51 years). 

Overall, the highest rates of disease occurred in children less than 2 years old. 

Rates of disease in Alaska Native versus non-Native populations by age group were variable; overall 

numbers of cases and rates by race and age group are presented in Figure 14. The highest rates of 

disease occurred in Alaska Native children less than two years of age, 64.6/100,000 persons per year and 

Alaska Native adults 55-64 years, 15.8/100,000 persons per year. 

0

10

20

30

0

2

4

6

8

Cases per 100,000

Number of Cases

Figure 12: Invasive Haemophilus influenzae, 

Cases & Rates by Region - Alaska, 2012

Cases

Rate
Surveillance of Invasive Bacterial Disease in Alaska, 2012 18 

Clinical Presentation 

The primary clinical presentation was determined by a review of the discharge diagnoses in each 

patient’s individual medical record associated with the invasive bacterial illness. For cases with more 

than one diagnosis, the most serious H. influenzae-related diagnosis was recorded as the primary clinical 

presentation. In 2012, pneumonia with bacteremia was the most common presentation (60% of cases). 

Thirteen (87%) of H. influenzae isolates were from blood samples in 2012, one was from cerebral spinal 

fluid and one from an unidentified other sterile site. 

0

10

20

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Age (yrs)

Figure 13: Invasive Haemophilus influenzae by 

Age Group - Alaska, 2012

0

20

40

60

80

0

1

2

3

4

5

6

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Number of Cases

Age (yrs)

Figure 14: Invasive Haemophilus influenzae, Cases & 

Rates by Age Group & Race - Alaska, 2012

AK Native

(# cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)
Surveillance of Invasive Bacterial Disease in Alaska, 2012 19 

Table 11: Primary Clinical Presentation of Invasive Haemophilus influenzae - Alaska, 2012 

Primary Presentation n (%) 

Pneumonia* 9 (60%) 

Bacteremia 2 (13%) 

Meningitis 2 (13%) 

Epiglottitis 1 (7%) 

Amnionitis 1 (7%) 

Total 15 

*with bacteremia 

Serotypes 

All isolates received at AIP are serotyped; 14 of the 15 cases in 2012 had isolates and were serotyped. 

The bacterial capsule is the basis for serotyping and is the primary virulence factor. Serotype b was the 

most common serotype in the past, but its prevalence has decreased with use of the childhood Hib 

vaccine. Surveillance of serotypes is important for monitoring vaccine effectiveness and emergence of

non-vaccine serotypes. 

Table 12: Serotypes of Invasive Haemophilus influenzae Cases by Race – Alaska, 2012 

 Alaska Native Non-Native 

Serotype Total n (%) <2 2-18 19-64 65+ <2 2-18 19-64 65+ 

a 3 (21%) 2 1 0 0 0 0 0 0 

b 1 (7%) 0 0 0 1 0 0 0 0 

f 4 (29%) 0 0 0 0 0 0 3 1 

NT* 6 (43%) 2 0 3 0 0 0 1 0 

Total 14 4 1 3 1 0 0 4 1 

*Non-typeable 

Hib

In recent years, the prevalence of H. influenzae type b has declined due to increased use of a childhood 

vaccine against this serotype. One case of Hib occurred in 2012 in an older adult. 

Hia 

Prior to 2002, H. influenzae type a (Hia) had not been detected in Alaska. Following an outbreak in 

2003 [9], cases have occurred sporadically until 2010 when an outbreak began in the YK Delta and 

continued through 2011 [10]. Three cases of Hia were detected in 2012; all occurred in AK Native 

children less than 5 years old. The rate of invasive disease caused by Hia in AK Native children less

than 2 years old for 2012 was 32.3/100,000. 

Antibiotic Resistance 

Fourteen H. influenzae isolates received at AIP were tested for susceptibility to chloramphenicol, 

ceftriaxone and TMP/sulfa. All 14 isolates were susceptible to ceftriaxone, one isolate had intermediate 

resistance to chloramphenicol, and 5 isolates were fully resistant to TMP/sulfa, 5 had intermediate 

resistance and 4 were susceptible. 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 20 

Table 13: Summary of Invasive Haemophilus influenzae Case Characteristics, Alaska, 2012 

Sex Age (Yrs) Race Residence 

Site of 

Isolation 

Clinical 

Presentation(s) Serotype* Associated Risk Factors Survived 

M 0.4 AK Native Other Blood Pneumonia NT None No 

M 0.6 AK Native Other Blood 

Meningitis, 

pneumonia, 

cellulitis 

a None Yes 

M 0.7 AK Native Other Blood Meningitis a None Yes 

M 1.3 AK Native Other Blood Pneumonia NT None Yes 

M 4.2 AK Native Other Blood Bacteremia a None Yes 

F 30.5 AK Native Other Other Amnionitis NT Smoking, alcohol 

abuse Yes 

M 50.3 AK Native Anchorage Blood Bacteremia Unknown Smoking, alcohol 

abuse Yes 

F 51 Non-Native Anchorage Blood Pneumonia f Smoking, chronic lung 

disease Yes 

F 52.4 Unknown Anchorage Blood Pneumonia f Smoking Yes 

M 55.1 AK Native Anchorage Blood Pneumonia NT Alcohol abuse Yes 

F 59.1 AK Native Other Blood Pneumonia NT Smoking, alcohol 

abuse Yes 

M 61 Unknown Anchorage Blood Pneumonia NT Chronic lung disease Yes 

F 62.1 Non-Native Other Blood Epiglottitis f None Yes 

F 68.9 Non-Native Anchorage Blood Pneumonia f None Yes 

M 78.9 AK Native Other CSF Pneumonia b None Yes 

*NT = non-typeable 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 21 

Invasive Neisseria meningitidis

Overall Incidence

Two cases of invasive Neisseria meningitidis were reported to AIP in 2012 for an overall rate of 

0.3/100,000. The Alaska rate is slightly higher than the ABCs 2012 national projected rate of 

0.15/100,000 [11]. There were no invasive N. meningitidis-related deaths in Alaska in 2012. 

Race 

Table 14: Invasive Neisseria meningitidis Cases by Race – Alaska, 2012 

Race 

Cases 

 n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 1 (50%) 0.5 100% 0 (0%) 

Non-Native 1 (50%) 0.2 0% 0 (0%) 

Total 2 50% 0 (0%) 

*Cases per 100,000 per percent distribution of Alaska 2010 population 

In 2012, 50% of the cases occurred in Alaska Natives. Age-adjusted rates were calculated for 

Alaska Natives and non-Natives. The age-adjusted rate ratio of N. meningitidis disease for the 

Alaska Native population compared with the non-Native population in 2012 was 2.5. 

Table 15: Summary of Invasive Neisseria meningitidis Case Characteristics, Alaska, 2012 

Sex Age (Yrs) Race Residence 

Site of 

Isolation 

Clinical 

Presentation(s) Serogroup 

Associated Risk 

Factors Survived 

F 0.3 Non-Native Other CSF Meningitis B None Yes 

M 18 AK Native Anchorage Blood Meningitis B None Yes 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 22 

Invasive group A Streptococcus

Overall Incidence

A total of 48 cases of invasive group A Streptococcus (GAS) were reported to AIP in 2012. The 

overall rate of invasive GAS disease in the state of Alaska was 6.6/100,000 persons per year. 

The Alaska rate is higher than the ABCs 2012 national projected rate of 3.4/100,000 [12]. In 

2012, there were 4 GAS-related deaths for a case fatality ratio of 8%. 

Seasonality 

Cases of group A Streptococcus occurred throughout the year in 2012 with no apparent trends in 

seasonality. The largest number of cases (n=7) occurred in June. 

Race

In 2012, 40% of invasive GAS cases in Alaska occurred in the Alaska Native population. The 

age-adjusted rate ratio of invasive GAS disease for the Alaska Native population compared with 

the non-Native population in 2012 was 3.1. 

Table 16: Invasive group A Streptococcus Cases by Race – Alaska, 2012 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 19 (40%) 14.7 26% 2 (11%) 

Non-Native 29† (60%) 4.7 48% 2 (7%) 

Total 48 40% 4 (8%) 

*Cases per 100,000 per percent distribution of Alaska 2010 population 

†Includes four cases for which race is unknown 

 

0

1

2

3

4

5

6

7

8

Number of Cases

Month of Culture

Figure 15: Invasive group A Streptococcus, by 

Month of Culture - Alaska, 2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 23 

Region 

Twenty-eight (58%) of the 48 invasive group A Streptococcus cases in 2012 were reported in the 

Anchorage area, 7 cases in the Interior, 5 cases in the YK Delta, 3 cases each in Kotzebue and 

Southeast and one case each in Bristol Bay and Norton Sound. The highest rates of disease 

occurred in the Kotzebue region (35.8/100,000) and the YK Delta (19.6/100,000). 

Age

Invasive group A Streptococcus cases reported in 2012 ranged in age from 3 months to 87.5 

years old; the median age was 49.7 years. Highest rates of disease occurred in children less than 

2 years old (13.9/100,000) and adults 65 years and older (14.1/100,000). 

When stratified by race, the highest rates of invasive group A streptococcal disease occurred in 

Alaska Native children less than two years old (48.4/100,000 persons per year). The highest 

0

10

20

30

40

0

10

20

30

Number of Cases

Cases per 100,00

Figure 16: Invasive GAS Disease, Cases & Rates 

by Region - Alaska, 2012

Cases

Rate

0

2

4

6

8

10

12

14

16

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Age (yrs)

Figure 17: Invasive group A Streptococcus by Age 

Group - Alaska, 2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 24 

GAS disease rate in the non-Native population occurred in adults 65 and older (11/100,000 

persons per year). 

Clinical Presentation

The primary clinical presentation was determined by a review of the discharge diagnoses in each 

patient’s individual medical record associated with the invasive bacterial illness. In cases with 

multiple discharge diagnoses, the most serious diagnosis related to the GAS infection was 

recorded as the primary clinical presentation. Table 17 shows the primary clinical presentations 

of invasive group A Streptococcus in Alaska for 2012. Eleven cases also presented with 

secondary diagnoses including pneumonia, septic arthritis and cellulitis. 

Group A Streptococcus was isolated from blood samples in 42 (87.5%) of 48 cases, four from 

joint fluid and two from a surgical specimen. 

 

Table 17: Primary Clinical Presentations of Invasive group A Streptococcus – Alaska, 2012 

Primary Presentation n (%) 

Bacteremia 13 (27%) 

Cellulitis* 11 (23%) 

Necrotizing fasciitis 6 (13%) 

Pneumonia* 4 (8%) 

Septic arthritis 4 (8%) 

Endocarditis 2 (4%) 

Empyema 2 (4%) 

Strep toxic shock 1 (2%) 

Pericarditis 1 (2%) 

Amnionitis 1 (2%) 

Endometritis 1 (2%) 

Bursitis 1 (2%) 

Other 1 (2%) 

Total 48 

*with bacteremia

0

10

20

30

40

50

60

0

2

4

6

8

10

12

14

16

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Number of Cases

Age (yrs)

Figure 18: Invasive group A Streptococcus, Cases 

& Rates by Age Group & Race - Alaska, 2012

AK Native

(# cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)
Surveillance of Invasive Bacterial Disease in Alaska, 2012 25 

Molecular Typing

Strain characterization of GAS has traditionally been based on serological identification of the M 

protein which is a major surface protein and an important GAS virulence factor. In the mid1990s, many reference labs started using a molecular approach based on sequencing of the Nterminal region of the M protein gene (emm gene). To date, more than 200 different emm types 

have been reported. While there are currently no vaccines available to protect against invasive 

GAS disease, baseline data on the burden of GAS disease to include emm typing are critical to 

evaluate the potential utility of any candidate vaccines.

In 2012, 38 invasive GAS isolates were emm typed at AIP. The most common emm types were 

emm 49 and emm 238 (18% each), followed by emm 3 (16%) and emm 89 (13%). The following 

graph shows emm typing trends over time. Strains that totaled ≤ 5 over the time period were not 

included. 

Associated Risk Factors

The presence of one or more associated risk factors was reported in 71% of invasive GAS cases 

in 2012. Diabetes was the most prevalent risk factor observed in adults followed by cigarette 

smoking and alcohol abuse. 

Table 18: Associated Risk Factors Identified in Invasive GAS Cases – Alaska, 2012* 

Risk Factor 

Adult Cases (≥ 18 years) 

n=44, Cases (%) 

Diabetes 13 (31%) 

Cigarette smoking 12 (29%) 

Alcohol abuse 11 (26%) 

Chronic lung disease 6 (14%) 

Immunosuppressive treatment 4 (10%) 

Injection drug use 0 (0%) 

Asplenia 0 (0%) 

*More than one risk factor was identified in several cases 

0

10

20

30

40

50

60

70

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Number of Cases

Figure 19: Invasive group A Streptococcus emm 

Typing Trends - Alaska, 2001-2012

1 3 5 12 28 41 49 73 82 87 89 92 108 114 238 Unknown
Surveillance of Invasive Bacterial Disease in Alaska, 2012 26 

Antibiotic Resistance 

Forty-three GAS isolates received at AIP were tested for susceptibility to penicillin, ceftriaxone, 

erythromycin, vancomycin, levofloxacin and clindamycin. All isolates tested were susceptible to 

penicillin, ceftriaxone, vancomycin, levofloxacin and clindamycin. Four isolates were resistant 

to both erythromycin; two isolates were emm 75, and one each were emm 3 and emm 58.
Surveillance of Invasive Bacterial Disease in Alaska, 2012 27 

Table 19: Summary of Invasive group A Streptococcus Case Characteristics, Alaska, 2012 

Sex 

Age 

(yrs) Race Residence 

Site of 

Isolation Clinical Presentation(s) 

emm

Type Associated Risk Factors Survived 

F 0.3 AK Native Other Blood Cellulitis 58 None Yes 

F 0.3 AK Native Other Blood Cellulitis, other 49 None Yes 

F 1.1 AK Native Other Blood Necrotizing fasciitis, 

cellulits 238 Chronic lung disease Yes 

M 2 Non-Native Anchorage Blood Pneumonia 1 None Yes

M 3.1 Non-Native Anchorage Blood Empyema, pneumonia 12 None Yes 

F 17.4 AK Native Other Blood Endometritis 75 Chronic lung disease Yes 

F 20.4 Unknown Anchorage Blood Bacteremia 1 None Yes 

M 22.5 AK Native Anchorage Joint fluid Bacteremia 49 None Yes 

M 24.5 Non-Native Anchorage Surgical 

specimen Empyema, pneumonia 238 Chronic lung disease Yes 

F 27.1 Non-Native Anchorage Blood Bacteremia 49 Immune suppressive treatment Yes 

F 28.6 Unknown Anchorage Blood Amnionitis 3 None Yes 

M 29.7 AK Native Other Blood Other ND None Yes 

F 35 AK Native Anchorage Blood Cellulitis 49 Alcohol abuse Yes 

M 38.4 AK Native Anchorage Blood STSS, other 238 Smoking, alcohol abuse Yes 

M 40.7 Non-Native Other Blood Cellulitis 89 None Yes 

M 44.6 Non-Native Other Joint fluid Bursitis 12 Smoking, alcohol abuse Yes 

F 44.9 Non-Native Anchorage Blood Cellulitis 82 Smoking, alcohol abuse, 

diabetes Yes 

M 45.1 Non-Native Anchorage Joint fluid Necrotizing fasciitis, 

cellulitis, bursitis 89 Smoking, alcohol abuse Yes 

M 46 Non-Native Other Blood Necrotizing fasciitis, 

cellulitis 78 None Yes 

F 46.1 AK Native Other Surgical 

specimen 

Necrotizing fasciitis, 

cellulitis 89 Smoking Yes 

M 46.5 AK Native Anchorage Joint fluid Necrotizing fasciitis, 

cellulitis 91 Smoking, alcohol abuse Yes 

M 47.1 AK Native Other Blood Septic arthritis ND Smoking, alcohol abuse, 

immune suppressive treatment Yes 

M 48.5 Non-Native Other Blood Cellulitis 49 Smoking Yes 

F 49.6 Non-Native Anchorage Blood Pericarditis, cellulitis 238 Diabetes Yes 

F 49.7 AK Native Other Blood Bacteremia 3 

Chronic lung disease, immune 

suppressive treatment, 

diabetes 

Yes 

F 50.9 Non-Native Anchorage Blood Cellulitis 238 Immune suppressive treatment Yes 

M 52.6 Non-Native Anchorage Blood Pneumonia 89 Chronic lung disease Yes 

M 54.8 Non-Native Anchorage Blood Bacteremia 28 Smoking, alcohol abuse Yes 

F 54.8 Non-Native Anchorage Blood Cellulitis 1 None Yes 

F 60 AK Native Anchorage Blood Bacteremia 19 Alcohol abuse No 

M 60.3 Unknown Anchorage Blood Endocarditis, septic 

arthritis 94 Smoking, alcohol abuse, diabetes No 

F 60.4 Non-Native Anchorage Blood Cellulitis 81 Diabetes Yes 

M 60.5 Non-Native Anchorage Blood Septic arthritis ND None Yes 

F 61.1 AK Native Other Blood Cellulitis 3 Diabetes Yes 

F 61.8 Non-Native Other Blood Bacteremia 28 None Yes 

F 62.6 AK Native Anchorage Blood Bacteremia 49 None Yes 

F 63 Non-Native Anchorage Blood Bacteremia 49 None Yes 

F 63.7 Non-Native Anchorage Blood Pneumonia 232 Diabetes Yes 

F 64.7 AK Native Anchorage Blood Bacteremia 108 Diabetes Yes 

F 65.1 Unknown Anchorage Blood Pneumonia 3 Chronic lung disease, diabetes Yes 

M 67.9 Non-Native Other Blood Necrotizing fasciitis, 

cellulitis ND Smoking, chronic lung disease, diabetes Yes 

F 68.2 Non-Native Other Blood Septic arthritis 12 None Yes 

F 71.6 Non-Native Other Blood Cellulitis 75 None Yes 

F 73.9 Non-Native Other Blood Bacteremia 89 Smoking, alcohol abuse Yes 

F 74.2 AK Native Other Blood Endocarditis 3 Chronic lung disease, diabetes No 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 28 

Sex 

Age 

(yrs) Race Residence 

Site of 

Isolation Clinical Presentation(s) 

emm

Type Associated Risk Factors Survived 

F 75.1 AK Native Other Blood Osteomyelitis, septic 

arthritis, cellulitis 238 Diabetes Yes 

F 78.1 AK Native Anchorage Blood Cellulitis 238 Diabetes Yes 

M 87.5 Non-Native Anchorage Blood Bacteremia 3 None No 

STSS = Streptococcal toxic shock syndrome 

ND = typing not done
Surveillance of Invasive Bacterial Disease in Alaska, 2012 29 

Invasive group B Streptococcus

Overall Incidence

A total of 33 cases of invasive group B Streptococcus (GBS) were reported to AIP in 2012. The 

overall rate of invasive GBS disease in the state of Alaska was 4.5/100,000 persons per year. 

The Alaska rate is lower than the ABCs 2012 national projected rate of 9/100,000 [13]. In 2012, 

there were four GBS-related deaths for a case fatality ratio of 12%. 

Seasonality

Cases of group B Streptococcus occurred throughout the year with no apparent trends in 

seasonality. 

 

Race

In 2012, 33% of invasive group B Streptococcus cases in Alaska occurred in the Alaska Native 

population; the age-adjusted rate was 8.3/100,000 persons per year which is over two times 

higher than the non-Native rate of 3.5/100,000 persons per year. 

Table 20: Invasive group B Streptococcus Cases by Race – Alaska, 2012 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 11 (33) 8.3 27 2 (18) 

Non-Native 22 (67)‡ 3.5 77 2 (9) 

Total 33 61 4 (12) 

*Cases per 100,000 per percent distribution of Alaska 2010 population 

‡Includes three cases for which race was unknown 

 

0

1

2

3

4

5

6

7

8

Number of Cases

Month of Culture

Figure 20: Invasive group B Streptococcus, by 

Month of Culture - Alaska, 2012
Surveillance of Invasive Bacterial Disease in Alaska, 2012 30 

Region 

In 2012, 20 (61%) of the 33 reported GBS cases occurred in Anchorage; five cases were reported 

in Interior Alaska, three cases each in the YK Delta and Southeast, and one case each in the 

Arctic Slope and Kotzebue. The highest rates of disease occurred in the Arctic Slope region 

(11.5/100,000), the Kotzebue region (11.9/100,000) and the YK Delta (11.8/100,000). 

Age

Invasive group B Streptococcus cases reported in 2012 ranged in age from newborn to 80.9 years 

old; the median age was 54.6 years. Highest rates of disease overall occurred in children less 

than two years old (23.2/100,000 persons per year). 

0

5

10

15

20

25

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Age (yrs)

Figure 21: Invasive group B Streptococcus by Age 

Group - Alaska, 2012

0

5

10

15

20

25

30

35

0

1

2

3

4

5

6

7

8

9

10

<2 2-4 5-18 19-54 55-64 65+

Cases per 100,000

Number of Cases

Age (yrs)

Figure 22: Invasive group B Streptococcus, Cases & 

Rates by Age Group & Race - Alaska, 2012

AK Native (#

cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)
Surveillance of Invasive Bacterial Disease in Alaska, 2012 31 

When stratified by race, the highest rates of disease occurred in AK Native children less than 2 

years of age (32.3/100,000 persons per year). There were three cases of early-onset disease (less 

than 7 days old) for a rate of 0.3/1,000 live births. 

Clinical Presentation

The primary clinical presentation was determined by a review of the discharge diagnoses in each 

patient’s individual medical record associated with the invasive bacterial illness. In cases with 

multiple discharge diagnoses, the most serious diagnosis related to the GBS infection was 

recorded as the primary clinical presentation. In 2012, the most common clinical presentation 

was bacteremia which occurred in 10 cases (30%). 

Group B Streptococcus was isolated from blood in 30 (91%) of 33 cases in 2012; two cases were 

isolated from joint fluid and one case from other sterile site. 

Table 21: Primary Clinical Presentations of Invasive group B Streptococcus – Alaska, 2012 

*with bacteremia

Antibiotic Resistance

Susceptibility testing was performed on 30 GBS isolates received in 2012. Results of the testing 

are presented in the following table. 

Table 22: Antibiotic Resistance in Invasive group B Streptococcus Isolates – Alaska, 2012 

Antibiotic Susceptible Intermediate Resistant I + R Total Tested 

Penicillin 30 (100%) 0 (0%) 0 (0%) 0 (0%) 30 

Ceftriaxone 30 (100%) 0 (0%) 0 (0%) 0 (0%) 30 

Erythromycin 12 (40%) 0 (0%) 18 (60%) 18 (60%) 30 

Tetracycline 3 (10%) 0 (0%) 27 (90%) 27 (90%) 42 

Levofloxacin 29 (97%) 0 (0%) 1 (3%) 1 (3%) 30 

Clindamycin 21 (70%) 0 (0%) 9 (30%) 9 (30%) 30 

Vancomycin 30 (100%) 0 (0%) 0 (0%) 0 (0%) 30 

All isolates tested were susceptible to penicillin, ceftriaxone and vancomycin. Resistance to 

tetracycline, erythromycin, clindamycin and levofloxacin was seen in 90%, 60%, 30% and 3%, 

Primary Presentation n (%) 

Bacteremia 10 (30%) 

Cellulitis* 9 (27%) 

Pneumonia* 4 (12%) 

Septic arthritis 3 (9%) 

Amnionitis 3 (9%) 

Endocarditis 1 (3%) 

Empyema 1 (3%) 

Osteomyelitis 1 (3%) 

Other 1 (3%) 

Total 33 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 32 

respectively, of isolates tested. Of the three early onset cases, all isolates were available for 

susceptibility testing. All three isolates showed resistance to at least one antibiotic. Two of the 

three isolates tested were resistant to tetracycline; two isolates were resistant to erythromycin and 

one isolate was resistant to clindamycin.
Surveillance of Invasive Bacterial Disease in Alaska, 2012 33 

Table 23: Summary of Invasive group B Streptococcus Case Characteristics, Alaska, 2012 

Sex Age (yrs) Race Residence 

Site of 

Isolation Clinical Presentation(s) Associated Risk Factors Survived 

M Newborn Non-Native Anchorage Blood Bacteremia None Yes 

M Newborn Non-Native Anchorage Blood Pneumonia None Yes 

F Newborn AK Native Other Blood Amnionitis None No 

F 37 days AK Native Other Blood Bacteremia None Yes

M 0.2 Non-Native Anchorage Blood Bacteremia None Yes 

F 24.5 Unknown Other Blood Cellulitis None Yes 

F 29.1 AK Native Anchorage Blood Amnionitis, endometritis Unknown Yes 

F 31 Non-Native Anchorage Other Amnionitis None Yes

F 33.6 AK Native Anchorage Blood Cellulitis Diabetes Yes 

M 34.2 Non-Native Anchorage Blood Cellulitis Chronic lung disease, diabetes Yes 

F 37.3 AK Native Anchorage Blood Bacteremia Alcohol abuse Yes 

M 48.2 AK Native Anchorage Blood Empyema, pneumonia Alcohol abuse, injection drug use Yes 

M 48.9 Unknown Anchorage Blood Cellulitis, osteomyelitis Diabetes Yes 

F 50.4 Non-Native Anchorage Blood Bacteremia None Yes 

M 52.6 Non-Native Other Blood Cellulitis, osteomyelitis Smoking, alcohol abuse Yes 

F 54.1 AK Native Other Joint fluid Other None Yes 

M 54.6 AK Native Anchorage Blood Bacteremia Diabetes Yes 

M 57.9 Non-Native Other Blood Endocarditis Diabetes Yes 

M 59.2 Non-Native Anchorage Joint fluid Septic arthritis Chronic lung disease, diabetes Yes 

F 59.7 AK Native Other Blood Bacteremia Immune suppressive treatment No 

M 60 Unknown Anchorage Blood Cellulitis Diabetes Yes 

F 63.2 Non-Native Other Blood Septic arthritis Chronic lung disease, diabetes No 

F 65.6 Non-Native Anchorage Blood Pneumonia None No

M 66.4 Non-Native Other Blood Cellulitis Smoking, chronic lung disease, 

diabetes Yes 

M 66.5 Non-Native Anchorage Blood Bacteremia None Yes 

M 69.9 Non-Native Other Blood Osteomyelitis Diabetes Yes 

M 71.9 Non-Native Anchorage Blood Bacteremia Smoking Yes 

M 73 Non-Native Anchorage Blood Cellulitis Diabetes Yes 

M 73.1 Non-Native Anchorage Blood Cellulitis Smoking Yes 

M 73.3 Non-Native Anchorage Blood Pneumonia, 

osteomyelitis Diabetes Yes 

F 73.9 AK Native Other Blood Pneumonia Smoking Yes 

M 78.5 AK Native Other Blood Bacteremia Unknown Yes

M 80.9 Non-Native Other Blood Septic arthritis Alcohol abuse, diabetes Yes 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 34 

References 

[1] State of Alaska, Department of Labor & Workforce Development. From 

http://laborstats.alaska.gov/pop/popest.htm

[2] Centers for Disease Control and Prevention. 2013. Active Bacterial Core Surveillance 

Report, Emerging Infections Program Network, Streptococcus pneumoniae, 2012.

[3] Hennessy TW, Singleton RJ, Bulkow LR, Bruden DL, Hurlburt DA, Parks, D, Moore M, 

Parkinson AJ, Schuchat A, Butler JC. Impact of heptavalent pneumococcal conjugate 

vaccine on invasive disease; antimicrobial resistance and colonization in Alaska Natives: 

progress towards elimination of a health disparity. Vaccine 2005;23:5464-73. 

[4] Singleton RJ, Hennessy TW, Bulkow LR, Hammitt LL, Zulz T, Hurlburt DA, Butler JC, 

Rudolph K, Parkinson A. Invasive pneumococcal disease caused by nonvaccine serotypes 

among Alaska Native children with high levels of 7-valent pneumococcal conjugate vaccine 

coverage. JAMA 2007;297(16):1784-92. 

[5] Wenger JD, Zulz T, Bruden D, Singleton R, Bruce MG, Bulkow L, Parks D, Rudolph K, 

Hurlburt D, Ritter T, Klejka J, Hennessy T. Invasive pneumococcal disease in Alaskan 

children: impact of the seven-valent pneumococcal conjugate vaccine and the role of water 

supply. Pediatr Infect Dis J 2010;29: 251-256. 

[6] State of Alaska, Department of Health & Human Services. Retrieved 3/17/11 from 

http://www.epi.hss.state.ak.us/bulletins/docs/b2009_24.pdf

[7] Clinical and Laboratory Standards Institute (CLSI). Performance Standards for 

Antimicrobial Susceptibility Testing; Nineteenth Informational Supplement. 2009; 29(3): 

M100-S19. p.21. 

[8] Centers for Disease Control and Prevention. 2013. Active Bacterial Core Surveillance 

Report, Emerging Infections Program Network, Haemophilus influenzae, 2012. 

[9] Hammitt LL, Block S, Hennessy TW, DeByle C, Peters H, Parkinson A, Singleton R, Butler 

JC. Outbreak of invasive Haemophilus influenzae serotype a disease. Pediatr Infect Dis J

2005;24(5): 453-6. 

[10]Bruce MG, Zulz T, DeByle C, Singleton R, Hurlburt D, Bruden D, Rudolph K, Hennessy T, 

Klejka J, Wenger JD. Haemophilus influenzae serotype a invasive disease, Alaska, USA, 

1983-2011. Emerg Infect Dis 2013;19(6): 932-7. 

[11]Centers for Disease Control and Prevention. 2013. Active Bacterial Core Surveillance 

Report, Emerging Infections Program Network, Neisseria meningitidis, 2012. 

[12]Centers for Disease Control and Prevention. 2013. Active Bacterial Core Surveillance 

Report, Emerging Infections Program Network, Group A Streptococcus, 2012. 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 35 

[13]Centers for Disease Control and Prevention. 2013. Active Bacterial Core Surveillance 

Report, Emerging Infections Program Network, Group B Streptococcus, 2012. 
Surveillance of Invasive Bacterial Disease in Alaska, 2012 36 

Appendix 

MIC Interpretive Standards Definitions: 

CLSI [7] provides recommended interpretive categories for various Minimum Inhibitory 

Concentration values (cut points) for each organism/antibiotic combination which are defined as 

follows: 

1. Susceptible (S): 

The “susceptible” category implies that isolates are inhibited by the usually achievable 

concentrations of antimicrobial agent when the recommended dosage is used for the site of 

infection. 

2. Intermediate (I): 

The “intermediate” category includes isolates with antimicrobial agent MICs that approach 

usually attainable blood and tissue levels and for which response rates may be lower than for 

susceptible isolates. The “intermediate” category implies clinical efficacy applicability in body 

sites where the drugs are physiologically concentrated (e.g., quinolones and β-lactams in urine) 

or when a higher dosage of a drug can be used (e.g., β-lactams). The “intermediate” category 

also includes a buffer zone which should prevent small, uncontrolled technical factors from 

causing major discrepancies in interpretations, especially for drugs with narrow 

pharmacotoxicity margins. 

3. Resistant (R): 

Resistant strains are not inhibited by the usually achievable concentrations of the agent with 

normal dosage schedules, and/or that demonstrate MICs or zone diameters that fall in the range 

where specific microbial resistance mechanisms are likely (e.g., β-lactamases) are likely, and 

clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies.