Surveillance of Invasive Bacterial Disease in Alaska, 2013 

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, 2013 2 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 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 28 

References 33 

Appendix 35 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 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, 2013 

In 2013, the total numbers of cases of invasive disease caused by these organisms reported to AIP were

106 S. pneumoniae, 21 H. influenzae, 0 N. meningitidis, 52 group A Streptococci (GAS) and 37 group B 

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

Arctic Slope

Interior

Kotzebue

Norton Sound

YK Delta

Bristol Bay

Anchorage

Southeast
Surveillance of Invasive Bacterial Disease in Alaska, 2013 5 

for 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, 2013 

Region 

S. pneumoniae 

n (rate*) 

H. influenzae 

n (rate*) 

N. meningitidis 

n (rate*) 

GAS 

n (rate*) 

GBS 

n (rate*) 

Anchorage 61 (12.5) 9 (1.8) 0 (0) 34 (7) 25 (5.1) 

Arctic Slope 3 (34) 0 (0) 0 (0) 0 (0) 0 (0) 

Bristol Bay 1 (13.7) 0 (0) 0 (0) 0 (0) 0 (0) 

Interior 14 (12.4) 1 (0.9) 0 (0) 5 (4.4) 5 (4.4) 

Kotzebue 3 (35.4) 1 (11.8) 0 (0) 4 (47.2) 0 (0) 

Norton Sound 1 (10.1) 0 (0) 0 (0) 0 (0) 0 (0) 

Southeast 8 (10.8) 2 (2.7) 0 (0) 3 (4) 6 (8.1) 

YK Delta 15 (57.7) 8 (30.8) 0 (0) 6 (23.1) 1 (3.8) 

Total 106 (14.4) 21 (2.9) 0 (0) 52 (7.1) 37 (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 736,399 persons in 2013 [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 2013, 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, 2013 6 

Invasive Pneumococcal Disease 

Overall Incidence

A total of 100 pneumococcal isolates were received at AIP in 2013. An additional 6 cases were detected 

through shared surveillance with the State DPH for a total of 106 cases of invasive pneumococcal 

disease. The overall rate for invasive pneumococcal disease in 2013 was 14.4 cases per 100,000 persons 

per year. Alaska rates for 2013 were higher than the Active Bacterial Core Surveillance (ABCs) 2013 

national projected rate of 10.7/100,000 [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 2013. The largest number of 

cases (n=13) was reported both in January and October. 

Race 

In 2013, the state population was comprised of 19% Alaska Native people (Alaska Natives 142,898, 

non-Natives 593,501) [1]. Of all reported S. pneumoniae cases in 2013, 47% occurred among Alaska 

Native people for a total of 50 cases; the age-adjusted rate was 36.9/100,000 persons per year. Fifty-six 

cases occurred among the non-Native population for an age-adjusted rate of 8.7/100,000 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 2013 was 4.2.

0

5

10

15

Number of Cases

Figure 2: Invasive Pneumococcal Disease, by 

Month of Culture - Alaska, 2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 7 

Table 2: Invasive Streptococcus pneumoniae Cases by Race – Alaska, 2013 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 50 (47) 36.9 62% 12 (24) 

Non-Native† 56 (53)† 8.7 63% 5 (9) 

Total 106 62% 17 (16) 

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

†Includes 10 cases for which race was unknown 

Region 

The highest percentage (58%) of invasive pneumococcal disease cases occurred in the Anchorage area 

in 2013. Rates of disease, however, were highest in the Kotzebue region (35.4/100,000 persons per 

year) and the YK Delta (57.7/100,000 persons per year). 

Age

Cases occurred in all age groups in 2013 ranging from 1 day to 97 years with a median age of 54 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 2013 occurred in Alaska Native children 

less than two years old (102.5/100,000 persons per year). 

0

20

40

60

80

0

20

40

60

80

Cases per 100,000

Number of Cases

Figure 3: Invasive Pneumococcal Disease, Cases 

& Rates by Region - Alaska, 2013

Cases

Rate
Surveillance of Invasive Bacterial Disease in Alaska, 2013 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. In 2013, rates have 

declined to 47.5/100,000. 

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,

0

20

40

60

80

100

120

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, 2013

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, 2004-2013

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 9 

however, increased to 177.5/100,000 in 2012 and declined to 102.5/100,000 in 2013. Five (83%) of the 

6 cases in 2013 were caused by serotypes not contained in the 13-valent vaccine. 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. In 2013, rates have 

increased in non-Native children less than 2 years to 26.3/100,000; three (75%) of four cases were 

caused by non-vaccine serotypes. 

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 

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, 2004-2013

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

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, 2004-2013

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 10 

presentation in 2013 (61%) followed by bacteremia (23%). Seventeen cases had a secondary 

pneumococcal-related diagnosis in 2012 - 9 pneumonia, 3, empyema, 2 meningitis, 1 cellulitis, 1 

osteomyelitis and 1 septic arthritis. 

In 2013, blood was the most common source of a positive culture which was used to identify 102 (96%) 

of 106 cases. Two cases were identified from pleural fluid and one each from a pericardial aspirate and 

surgical specimen. 

Mortality 

In 2013, the overall case fatality ratio for S. pneumoniae in Alaska was 16% (17 deaths out of 106 

cases). The case fatality ratio for AK Natives was slightly higher (24%, 12 deaths) than non-Natives 

(9%, 5 deaths). The largest number of deaths occurred in the 65 and older age category (7 deaths), 

however, the highest case fatality ratio occurred in the 2-4 age category (2 deaths) 28.6%. 

65

24

6 3 3 1 1 1 1 1

0

20

40

60

80

Number of Cases

Figure 8: Primary Clinical Presentations of 

Invasive Pneumococcal Disease - Alaska, 2013

*with bacteremia

0

5

10

15

20

25

30

35

0

1

2

3

4

5

6

7

8

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

Number of Deaths

Case Fatality Ratio (%)

Age (yrs)

Figure 9: Invasive Pneumococcal Deaths & Case 

Fatality Ratios by Age Group - Alaska, 2013

Deaths

CFR
Surveillance of Invasive Bacterial Disease in Alaska, 2013 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, 2013 

 Alaska Native Non-Native 

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

03 4 (4) - - - - - - 3 1 

04 1 (1) - - 1 - - - - - 

06C 7 (7) - - 1 1 - - 2 3 

07C 2 (2) - - 1 - - - - 1 

07F 5 (5) - - 3 - - - - 2 

08 4 (4) - 2 1 - - - 1 - 

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

10A 4 (4) - - 1 - 2 - 1 - 

11A 3 (3) - - - - - 1 1 1 

12F 6 (6) 1 1 3 - - - - 1 

14 1 (1) - - - - - - 1 - 

15A 3 (3) - - 1 - - - 2 - 

15B 3 (3) - 1 - - 1 - 1 - 

15C 3 (3) 1 - 1 - - - 1 - 

16F 10 (10) - 1 3 1 - 1 2 2 

17F 3 (3) - - 1 2 - - - - 

19A 3 (3) 1 - 1 - - - 1 - 

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

22F 13 (13) - 3 2 2 - - 1 5 

23A 4 (4) - - 3 - - - 1 - 

23B 4 (4) - 1 - - - 1 1 1 

31 3 (3) - - 2 - - 1 - - 

33F 3 (3) 1 - 1 - - - 1 - 

34 3 (3) - - - - - - 3 - 

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

NT 1 (1) - - - - - 1 - - 

Total 100 6 9 28 6 4 5 24 18 

In 2013, the most common pneumococcal serotypes were 22F, (13 isolates, 13%), 16F (10 isolates, 

10%) and 6C (7 isolates, 7%). 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. 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 (46%) of serotype 22F cases and 

serotype 16F cases (70%) occurred in the Anchorage area in 2013. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 12 

Table 4: Invasive Pneumococcal Serotype Distribution by Region – Alaska, 2013 

Serotype 

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

03 3 - - 1 - - - - 

04 1 - - - - - - - 

06C 2 - - 2 - - 3 - 

07C 2 - - - - - - - 

07F 4 - - 1 - - - - 

08 1 - 1 - - - - 2 

09N 1 1 - 1 - - - - 

10A 3 - - 1 - - - - 

11A 3 - - - - - - - 

12F 2 - - 1 1 - - 2 

14 1 - - - - - - - 

15A 3 - - - - - - - 

15B 2 - - - - - - 1 

15C 1 - - - - 1 1 - 

16F 7 - - - - - 1 2 

17F 1 - - 2 - - - - 

19A - - - 1 - - 1 1 

19F 1 - - - - - - - 

22F 6 1 - 3 2 - - 1 

23A 2 - - 1 - - - 1 

23B 3 - - - - - - 1 

31 1 1 - - - - - 1 

33F 2 - - - - - - 1 

34 2 - - - - - 1 - 

35B 2 - - - - - - 1 

NT 1 - - - - - - - 

Unknown 4 - - - - - 1 1 

Total 61 3 1 14 3 1 8 15 

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 2013 that were due to serotypes found in the PCV13 vaccine. There were two cases of 

pneumococcal disease caused by serotypes contained in the PCV13 vaccine in children less than 5 years 

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. 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 13 

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

– Alaska, 2013 

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

<2 1 (17%) of 6 1 (25%) of 4 2 (20%) of 10 

2-4 0 (0%) of 4 0 (0%) of 3 0 (0%) of 7 

5+ 5 (13%) of 39 8 (18%) of 44 13 (16%) of 83 

Total 6 (12%) of 49 9 (18%) of 51 15 (15%) of 100 

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 2013, for persons 65 years and older, 12 (50%) of 24 cases serotyped 

were potentially vaccine preventable invasive pneumococcal illnesses. 

Vaccine Failures 

In 2013, pneumococcal vaccine status was known for 101 (95%) of the 106 cases; 46 cases (46%) of 

cases with known vaccine status did receive a pneumococcal vaccine prior to illness and 55 cases (54%)

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 

was one vaccine failure in 2013. The child had received 3 doses of PCV13 and had no underlying 

conditions; serotype of the case was 19A. 

Potentially Preventable Deaths

Overall, 35% of all pneumococcal-related mortality in 2013 was potentially preventable with the use of

the 23-valent polysaccharide vaccine in persons over 2 years old; 47% 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, 2013 

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

PCV13 0 0 0 0 0 0 0 

Ps23V 1 (100%) 1 (50%) 0 1 (25%) 1 (33%) 3 (43%) 7 (41%) 

Non-Vaccine 0 1 (50%) 0 3 (75%) 1 (33%) 3 (43%) 8 (47%) 

Unknown 0 0 0 0 1 (33%) 1 (14%) 2 (12%) 

Total 1 2 0 4 3 7 17 

Seven of the 17 deaths in 2013 from invasive S. pneumoniae occurred from serotypes contained within 

the Ps23V vaccine; three of the deaths were in individuals eligible for the vaccine. Two deaths occurred 

in vaccinated individuals; time since vaccination was 11 and 8 years. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 14 

Table 7: Invasive Pneumococcal Disease, Serotypes of Fatal Cases – Alaska, 2013 

Serotype 

Deaths 

n (%) 

Serotype 

Frequency (n) 

04†* 1 (100%) 1 

06C 1 (14%) 7 

12F* 2 (33%) 6 

15C 1 (33%) 3 

16F 4 (40%) 10 

17F* 1 (33%) 3 

22F* 3 (23%) 13 

23A 2 (50%) 4 

† 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 75% of invasive pneumococcal 

cases in 2013. Cigarette smoking was the most prevalent risk factor observed in adults followed by 

alcohol abuse and chronic lung disease. 

Table 8: Associated Risk Factors Identified in Invasive Pneumococcal Cases – Alaska, 2013* 

Risk Factor 

Adult Cases (≥ 18 years) 

n=82, Cases (%) 

Cigarette smoking 27 (33%) 

Alcohol abuse 25 (31%) 

Chronic lung disease 24 (29%) 

Diabetes 10 (12%) 

Immunosuppressive treatment 3 (4%) 

Injection drug use 3 (4%) 

Asplenia 0 (0%) 

*More than one risk factor was identified in several cases 

Antibiotic Resistance

Susceptibility testing was performed on 100 isolates received in 2013. Results of the testing are 

presented in the following table. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 15 

Table 9: Antibiotic Resistance in Invasive Streptococcus pneumoniae Isolates – Alaska, 2013 

Antibiotic Susceptible Intermediate Resistant I + R Total Tested 

Penicillin 87 (87%) 0 (0%) 13 (13%) 13 (13%) 100 

TMP-sulfa 92 (92%) 3 (3%) 5 (5%) 8 (8%) 100 

Erythromycin 84 (84%) 0 (0%) 16 (16%) 16 (16%) 100 

Ceftriaxone 97 (97%) 3 (3%) 0 (0%) 3 (3%) 100 

Tetracycline 94 (94%) 0 (0%) 6 (6%) 6 (6%) 100 

Chloramphenicol 98 (98%) 0 (0%) 2 (2%) 2 (2%) 100 

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

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

Clindamycin 96 (96%) 0 (0%) 4 (4%) 4 (4%) 100 

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, 1993 - 2013

Penicillin

Erythro

TMP-Sulfa

Tet
Surveillance of Invasive Bacterial Disease in Alaska, 2013 16 

Invasive Haemophilus influenzae

Overall Incidence 

In 2013, there were 21 cases of invasive Haemophilus influenzae in Alaska, for a statewide rate of 

2.9/100,000 persons per year. This rate is higher than the national projected rate of 1.77/100,000 

persons per year [8]. There were two deaths associated with H. influenzae in 2013 for a case fatality 

ratio of 9.5%. 

Seasonality 

Cases of invasive H. influenzae occurred throughout 2013; however, due to the small number of cases, 

trends in seasonality cannot be determined. The largest number of cases (n=6) occurred in October. 

Region 

The highest rates of disease caused by invasive H. influenzae cases in 2013 were in the regions of the 

YK Delta, 30.8/100,000 (8 cases), and Kotzebue, 11.8/100,000 (1 case). Although a large number of 

cases occurred in the Anchorage area (9 cases), the rate was much lower (1.8/100,000). 

0

1

2

3

4

5

6

7

Number of Cases

Month of Culture

Figure 11: Haemophilus influenzae Disease by 

Month of Culture - Alaska, 2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 17 

Race 

Table 10: Invasive Haemophilus influenzae Cases by Race – Alaska, 2013 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 12 (57%) 7.4 50% 2 (17%) 

Non-Native 9† (43%) 1.3 56% 0 (0%) 

Total 21 52% 2 (9.5%) 

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

†Includes one case for which race is unknown

In 2013, 57% 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 2013 was 5.7. 

Age 

H. influenzae cases ranged in age from newborn to 86 years of age in 2013 (median 34 years). Overall, 

the highest rates of disease occurred in children less than 2 years old (42.7/100,000). 

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, 136.7/100,000 persons per year 

and Alaska Native adults 65 years and older, 21.2/100,000 persons per year. 

0

10

20

30

40

0

2

4

6

8

10

Cases per 100,000

Number of Cases

Figure 12: Invasive Haemophilus influenzae, 

Cases & Rates by Region - Alaska, 2013

Cases

Rate
Surveillance of Invasive Bacterial Disease in Alaska, 2013 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 2013, pneumonia with bacteremia and bacteremia alone were the most common 

presentation (38% of cases each). 

Seventeen (81%) H. influenzae isolates were from blood samples in 2013, and four were from 

cerebrospinal fluid. 

0

10

20

30

40

50

<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, 2013

0

20

40

60

80

100

120

140

160

0

1

2

3

4

5

6

7

8

9

<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, 2013

AK Native

(# cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)
Surveillance of Invasive Bacterial Disease in Alaska, 2013 19 

Table 11: Primary Clinical Presentation of Invasive Haemophilus influenzae - Alaska, 2013 

Primary Presentation n (%) 

Pneumonia* 8 (38%) 

Bacteremia 8 (38%) 

Meningitis 4 (19%) 

Amnionitis 1 (5%) 

Total 21 

*with bacteremia 

Serotypes 

All isolates received at AIP are serotyped; all 21 cases in 2013 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 nonvaccine serotypes. 

Table 12: Serotypes of Invasive Haemophilus influenzae Cases by Race – Alaska, 2013 

 Alaska Native Non-Native 

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

a 5 (24%) 5 0 0 0 0 0 0 0 

b 2 (10%) 2 0 0 0 0 0 0 0 

f 3 (14%) 0 0 0 1 0 0 1 1 

NT* 11 (52%) 1 0 2 1 1 0 1 5 

Total 21 8 0 2 2 1 0 2 6 

*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. Two cases of Hib occurred in 2013 in children less than 1 year old. One 

child had received one dose of Hib vaccine; vaccine status for the second child was unknown. 

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]. Five cases of Hia were detected in 2013; all occurred in AK Native 

children less than 2 years old. The rate of invasive disease caused by Hia in AK Native children less

than 2 years old for 2013 was 85.4/100,000. 

Antibiotic Resistance 

Twenty-one H. influenzae isolates received at AIP were tested for susceptibility to ampicillin, 

chloramphenicol and TMP/sulfa; 19 isolates were tested for susceptibility to ceftriaxone. All isolates 

tested were susceptible to ceftriaxone, one isolate had intermediate resistance to chloramphenicol, 6 

isolates were resistant to ampicillin (2 intermediate, 4 fully resistant) and 15 isolates were resistant to 

TMP/sulfa (5 intermediate and 10 fully resistant). 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 20 

Table 13: Summary of Invasive Haemophilus influenzae Case Characteristics, Alaska, 2013 

Sex Age (Yrs) Race Residence 

Site of 

Isolation 

Clinical 

Presentation(s) Serotype* Associated Risk Factors Survived 

M Newborn Non-Native Anchorage Blood Amnionitis NT None Yes 

F Newborn AK Native Other Blood Bacteremia NT None Yes 

M 0.4 AK Native Other CSF Meningitis a None Yes 

M 0.5 AK Native Other CSF Meningitis a None Yes 

M 0.5 AK Native Other CSF Meningitis b Diabetes No 

F 0.6 AK Native Other Blood Bacteremia b None Yes 

M 0.6 AK Native Other Blood Pneumonia a None Yes 

F 0.9 AK Native Other CSF Meningitis a None Yes 

F 1 AK Native Other Blood Bacteremia a None Yes 

F 22.3 Non-Native Anchorage Blood Bacteremia NT None Yes 

M 34.2 AK Native Anchorage Blood Pneumonia NT None Yes 

F 48.6 AK Native Anchorage Blood Pneumonia NT Smoking, chronic lung 

disease, alcohol abuse Yes 

F 63.4 Non-Native Anchorage Blood Bacteremia f Diabetes Yes 

F 68.9 AK Native Other Blood Pneumonia f None Yes 

M 69.3 Non-Native Other Blood Pneumonia NT Smoking, chronic lung 

disease Yes 

M 72.7 AK Native Anchorage Blood Pneumonia NT Smoking, chronic lung 

disease No 

F 74.8 Non-Native Other Blood Pneumonia NT None Yes

M 81 Non-Native Anchorage Blood Bacteremia NT None Yes 

M 81.6 Non-Native Anchorage Blood Bacteremia NT None Yes 

M 85.3 Non-Native Anchorage Blood Pneumonia f Chronic lung disease Yes 

F 86.3 Unknown Other Blood Bacteremia NT Chronic lung disease Yes 

*NT = non-typeable 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 21 

Invasive Neisseria meningitidis

Overall Incidence

No cases of invasive Neisseria meningitidis were reported to AIP in 2013. The ABCs national projected 

rate for N. meningitidis in 2013 was 0.14/100,000 [9]. 

 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 22 

Invasive group A Streptococcus

Overall Incidence

A total of 52 cases of invasive group A Streptococcus (GAS) were reported to AIP in 2013. The overall 

rate of invasive GAS disease in the state of Alaska was 7.1/100,000 persons per year. The Alaska rate is 

higher than the ABCs 2013 national projected rate of 3.7/100,000 [12]. In 2013, there were 7 GASrelated deaths for a case fatality ratio of 14%. 

Seasonality 

Cases of group A Streptococcus occurred throughout the year in 2013 with no apparent trends in 

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

Race

In 2012, 40% of invasive GAS cases in Alaska occurred in the Alaska Native population. The ageadjusted rate ratio of invasive GAS disease for the Alaska Native population compared with the nonNative population in 2013 was 3.3. 

Table 14: Invasive group A Streptococcus Cases by Race – Alaska, 2013 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 23 (44%) 16.1 52% 2 (9%) 

Non-Native 29† (56%) 4.9 69% 5 (21%)‡ 

Total 52 62% 7 (14%) 

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

†Includes four cases for which race is unknown 

‡Outcome unknown in one case 

 

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, 2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 23 

Region 

Thirty-four (65%) of the 52 invasive group A Streptococcus cases in 2013 were reported in the 

Anchorage area, 6 cases in the YK Delta, 5 cases in the Interior, 4 cases in Kotzebue and 3 cases in 

Southeast. The highest rates of disease occurred in the Kotzebue region (47.2/100,000) and the YK 

Delta (23.1/100,000). 

Age

Invasive group A Streptococcus cases reported in 2013 ranged in age from 2 months to 84 years old; the 

median age was 43 years. Highest rates of disease occurred in children less than 2 years old 

(23.7/100,000). 

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

Native children less than two years old (85.4/100,000 persons per year). The highest GAS disease rate 

in the non-Native population occurred in adults 65 and older (10.3/100,000 persons per year). 

0

10

20

30

40

50

0

10

20

30

40

Number of Cases

Cases per 100,00

Figure 16: Invasive GAS Disease, Cases & Rates 

by Region - Alaska, 2013

Cases

Rate

0

5

10

15

20

25

<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, 2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 24 

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 15 shows the primary clinical presentations of invasive group A 

Streptococcus in Alaska for 2013. Eight cases also presented with secondary diagnoses including 

pneumonia, septic arthritis and cellulitis. 

Group A Streptococcus was isolated from blood samples in 49 (94%) of 52 cases, two from a surgical 

specimen and one from joint fluid. 

 

Table 15: Primary Clinical Presentations of Invasive group A Streptococcus – Alaska, 2013 

Primary Presentation n (%) 

Bacteremia 17 (33%) 

Cellulitis* 10 (19%) 

Pneumonia* 9 (17%) 

Necrotizing fasciitis 6 (12%) 

Septic arthritis 3 (6%) 

Empyema 2 (4%) 

Endocarditis 1 (2%) 

Peritonitis 1 (2%) 

Endometritis 1 (2%) 

Other 1 (2%) 

Unknown 1 (2%) 

Total 52 

*with bacteremia

Associated Risk Factors

The presence of one or more associated risk factors was reported in 79% of invasive GAS cases in 2013. 

Cigarette smoking was the most prevalent risk factor observed in adults followed by diabetes and 

alcohol abuse. 

0

10

20

30

40

50

60

70

80

90

0

2

4

6

8

10

12

14

16

18

20

<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, 2013

AK Native

(# cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)
Surveillance of Invasive Bacterial Disease in Alaska, 2013 25 

Table 16: Associated Risk Factors Identified in Invasive GAS Cases – Alaska, 2013* 

Medical Condition/Risk 

Factor 

Adult Cases (≥ 18 years) 

n=44, Cases (%) 

Cigarette smoking 13 (30%) 

Diabetes 11 (25%) 

Alcohol abuse 9 (20%) 

Chronic lung disease 7 (16%) 

Injection drug use 4 (9%) 

Immunosuppressive treatment 0 (0%) 

Asplenia 0 (0%) 

*More than one risk factor was identified in several cases 

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 mid-1990s, many 

reference labs started using a molecular approach based on sequencing of the N-terminal 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, several M protein-based 

vaccines are in development. Therefore, baseline data on the burden of GAS disease to include emm

typing are critical to evaluate the potential utility of these candidate vaccines.

In 2013, 50 invasive GAS isolates were emm typed at AIP. The most common emm types were emm

101 (26%) and emm 89 (16%). The following graph shows emm typing trends over time. Strains that 

totaled ≤ 10 over the time period were not included. 

Antibiotic Resistance 

Forty-nine 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 and levofloxacin. Two isolates were resistant to both erythromycin 

and clindamycin; both isolates were emm type 11. 

0

10

20

30

40

50

60

70

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Number of Cases

Figure 19: Invasive group A Streptococcus emm 

Typing Trends - Alaska, 2001-2013

1 3 5 12 28 41 49 73 82 87 89 92 101 108 Unknown
Surveillance of Invasive Bacterial Disease in Alaska, 2013 26 

Table 17: Summary of Invasive group A Streptococcus Case Characteristics, Alaska, 2013 

Sex 

Age 

(yrs) Race Residence 

Site of 

Isolation Clinical Presentation(s) 

emm

Type Associated Risk Factors Survived 

F 0.2 AK Native Other Blood Bacteremia 49 None Yes 

M 0.2 AK Native Anchorage Blood Bacteremia 108 None Yes 

M 0.2 AK Native Other Blood Bacteremia 49 None Yes 

M 0.6 AK Native Other Blood Empyema, pneumonia 108 None Yes 

F 1.5 AK Native Other Blood Septic arthritis 238 None Yes 

M 3.2 AK Native Other Blood Bacteremia 49 None Yes 

M 3.6 AK Native Other Blood Bacteremia 1 None No 

M 12.7 Non-Native Other Blood Bacteremia 3 Chronic lung disease Yes 

M 22.1 Non-Native Anchorage Blood Cellulitis 52 Diabetes Yes 

M 25.5 AK Native Other Blood Other ND Chronic lung disease Yes 

F 26.6 Non-Native Anchorage Blood Empyema, pneumonia 82 Smoking, injection drug use Yes 

F 30.5 AK Native Other Blood Bacteremia 12 None Yes

F 32.5 AK Native Other Surgical 

specimen Cellulitis 101 Smoking Yes 

F 33.1 AK Native Anchorage Blood Cellulitis 101 Smoking Yes 

M 33.2 Non-Native Anchorage Blood Cellulitis 87 Smoking, injection drug use Yes 

F 35 Non-Native Other Blood Endometritis 28 None Yes 

M 35.3 Non-Native Anchorage Blood Pneumonia, cellulitis ND Injection drug use Yes 

M 37.3 Non-Native Anchorage Blood Cellulitis 101 Smoking, diabetes Yes 

M 37.4 Non-Native Anchorage Blood Cellulitis 85 Smoking, chronic lung disease Yes 

F 37.6 Non-Native Anchorage Blood Bacteremia 89 Diabetes Yes 

F 39.9 Non-Native Anchorage Blood Necrotizing fasciitis 238 Injection drug use Yes 

M 40.1 AK Native Other Blood Bacteremia 89 Alcohol abuse Yes 

M 41 AK Native Anchorage Blood Bacteremia 101 Smoking, alcohol abuse, 

diabetes Yes 

F 41.6 AK Native Other Blood Cellulitis 11 None Yes

F 41.7 Non-Native Other Blood Bacteremia 1 Diabetes No 

M 43 Non-Native Anchorage Blood Necrotizing fasciitis 92 None Yes 

M 43.1 Unknown Anchorage Blood Cellulitis, necrotizing 

fasciitis 92 None Yes 

M 43.5 AK Native Anchorage Blood Septic arthritis, 

osteomyelitis 101 None Yes 

M 44.5 AK Native Anchorage Blood Bacteremia 101 None No 

F 44.8 AK Native Anchorage Joint fluid Septic arthritis 101 Smoking, alcohol abuse Yes 

M 46 AK Native Anchorage Blood Pneumonia 101 Smoking, alcohol abuse Yes 

M 47.1 AK Native Anchorage Blood Pneumonia 101 Alcohol abuse Yes 

M 47.5 Non-Native Other Blood Cellulitis, necrotizing 

fasciitis 1 Diabetes Yes 

F 47.7 AK Native Anchorage Blood Cellulitis 11 Chronic lung disease Yes 

M 50.2 Non-Native Anchorage Surgical 

specimen 

Cellulitis, osteomyelitis, 

necrotizing fasciitis 89 Smoking, alcohol abuse Yes 

F 51.7 AK Native Other Blood Bacteremia 89 Chronic lung disease Yes 

F 52 Non-Native Anchorage Surgical 

specimen Necrotizing fasciitis 89 Smoking, chronic lung disease Yes 

F 52.5 Non-Native Anchorage Blood Pneumonia 89 Smoking Yes 

M 52.6 Non-Native Anchorage Blood Bacteremia 101 Smoking, alcohol abuse No 

M 53.3 Non-Native Anchorage Blood Bacteremia 44 None Yes 

F 53.5 AK Native Other Blood Bacteremia 27 Chronic lung disease Yes 

M 56.7 Non-Native Anchorage Blood Pneumonia 101 Diabetes Yes 

F 60 AK Native Anchorage Blood Cellulitis 101 Smoking, alcohol abuse Yes 

F 60.3 Non-Native Anchorage Blood Peritonitis 28 Diabetes Yes 

M 61.1 Non-Native Anchorage Blood Cellulitis 28 Alcohol abuse Yes 

M 62.1 Non-Native Other Blood Bacteremia 3 Diabetes Yes 

M 74 Unknown Anchorage Blood Pneumonia, cellulitis 82 Diabetes Yes 

M 74.1 Unknown Anchorage Blood Pneumonia 3 None Yes

M 76.6 Unknown Anchorage Blood Endocarditis, pneumonia 101 Chronic lung disease, diabetes Yes 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 27 

Sex 

Age 

(yrs) Race Residence 

Site of 

Isolation Clinical Presentation(s) 

emm

Type Associated Risk Factors Survived 

F 82.1 Non-Native Anchorage Blood Pneumonia 12 None No 

M 82.4 Non-Native Anchorage Blood Cellulitis 89 Chronic lung disease No 

M 84.2 Non-Native Anchorage Blood Pneumonia 89 None No 

ND = typing not done
Surveillance of Invasive Bacterial Disease in Alaska, 2013 28 

Invasive group B Streptococcus

Overall Incidence

A total of 37 cases of invasive group B Streptococcus (GBS) were reported to AIP in 2013. The 

overall rate of invasive GBS disease in the state of Alaska was 5.2/100,000 persons per year. 

The Alaska rate is lower than the ABCs 2013 national projected rate of 9.2/100,000 [13]. In 

2013, there was one GBS-related death for a case fatality ratio of 2.7%. 

Seasonality

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

seasonality. 

Race

In 2013, 22% of invasive group B Streptococcus cases in Alaska occurred in the Alaska Native 

population; the age-adjusted rate was 6.5/100,000 persons per year which is higher than the nonNative rate of 4.5/100,000 persons per year. 

Table 18: Invasive group B Streptococcus Cases by Race – Alaska, 2013 

Race 

Cases 

n (%) 

Age Adjusted 

Rate* % Male 

Deaths 

n (%) 

Alaska Native 8 (22) 6.5 38 0 (0) 

Non-Native 29 (78)‡ 4.5 41 1 (2.7) 

Total 37 40 1 (2.7) 

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

‡Includes one case 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, 2013
Surveillance of Invasive Bacterial Disease in Alaska, 2013 29 

Region 

In 2013, 25 (68%) of the 37 reported GBS cases occurred in Anchorage; six cases were reported 

in Southeast Alaska, five cases in the Interior, and one case in the YK Delta. The highest rates of 

disease occurred in Southeast Alaska (8.1/100,000) and Anchorage (5.1/100,000). 

Age

Invasive group B Streptococcus cases reported in 2013 ranged in age from newborn to 84.9 years 

old; the median age was 59.6 years. Highest rates of disease overall occurred in children less 

than two years old (28.5/100,000 persons per year). 

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

years of age (32.9/100,000 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. 

0

5

10

15

20

25

30

<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, 2013

0

5

10

15

20

25

30

35

0

2

4

6

8

10

12

<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, 2013

AK Native (#

cases)

Non-Native

(# cases)

AK Native

(rate)

Non-Native

(rate)
Surveillance of Invasive Bacterial Disease in Alaska, 2013 30 

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 2013, the most common clinical presentation 

was bacteremia which occurred in 16 cases (43%). 

Group B Streptococcus was isolated from blood in 33 (89%) of 37 cases in 2013; one case was 

isolated from joint fluid, one case from synovial fluid, one from peritoneal fluid and one case 

from another sterile site. 

Table 19: Primary Clinical Presentations of Invasive group B Streptococcus – Alaska, 2013 

*with bacteremia

Antibiotic Resistance

Susceptibility testing was performed on 35 GBS isolates received in 2013. Results of the testing 

are presented in the following table. 

Table 20: Antibiotic Resistance in Invasive group B Streptococcus Isolates – Alaska, 2013 

Antibiotic Susceptible Intermediate Resistant I + R Total Tested 

Penicillin 35 (100%) 0 (0%) 0 (0%) 0 (0%) 35 

Ceftriaxone 35 (100%) 0 (0%) 0 (0%) 0 (0%) 35 

Erythromycin 11 (30%) 0 (0%) 24 (70%) 24 (70%) 35 

Tetracycline 5 (14%) 0 (0%) 30 (86%) 30 (86%) 35 

Levofloxacin 35 (100%) 0 (0%) 0 (0%) 0 (0%) 35 

Clindamycin 23 (66%) 0 (0%) 12 (34%) 12 (34%) 35 

Vancomycin 35 (100%) 0 (0%) 0 (0%) 0 (0%) 35 

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

Resistance to tetracycline, erythromycin, and clindamycin was seen in 86%, 70%, and 34%, 

Primary Presentation n (%) 

Bacteremia 16 (43) 

Cellulitis* 8 (22) 

Pneumonia* 3 (8) 

Endocarditis 2 (5) 

Septic arthritis 1 (3) 

Amnionitis 1 (3) 

Meningitis 1 (3) 

Necrotizing fasciitis 1 (3) 

Osteomyelitis 1 (3) 

Peritonitis 1 (3) 

Other 2 (5) 

Total 37 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 31 

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 two antibiotics. All three 

isolates tested were resistant to erythromycin and tetracycline; one isolate was also resistant to 

clindamycin.
Surveillance of Invasive Bacterial Disease in Alaska, 2013 32 

Table 21: Summary of Invasive group B Streptococcus Case Characteristics, Alaska, 2013 

Sex Age (yrs) Race Residence 

Site of 

Isolation Clinical Presentation(s) Associated Risk Factors Survived 

F Newborn Non-Native Anchorage Blood Bacteremia None Yes 

F Newborn Non-Native Anchorage Blood Amnionitis None Yes 

M Newborn Non-Native Other Blood Bacteremia None Yes 

M 0.1 Non-Native Anchorage Blood Bacteremia None Yes 

F 0.1 AK Native Other Blood Bacteremia None Yes 

F 0.1 Non-Native Anchorage Blood Meningitis None Yes 

F 24 Non-Native Other Other Necrotizing fasciitis None Yes 

F 32.7 Non-Native Anchorage Blood Endocarditis Smoking, injection drug use Yes 

M 40.6 Non-Native Anchorage Blood Bacteremia Alcohol abuse Yes 

M 45.1 Non-Native Anchorage Blood Bacteremia Diabetes Yes 

M 46.1 AK Native Other Synovial 

fluid Septic arthritis Smoking, alcohol abuse Yes 

F 49.3 Non-Native Anchorage Blood Bacteremia Diabetes Yes 

M 49.6 Non-Native Other Blood Bacteremia Alcohol abuse Yes 

F 51 Non-Native Anchorage Blood Cellulitis None Yes

F 55.3 Non-Native Anchorage Joint fluid Other Chronic lung disease, diabetes Yes 

F 55.4 Non-Native Anchorage Blood Cellulitis Smoking, diabetes Yes 

M 58.1 AK Native Other Blood Other Diabetes Yes 

F 59.2 Non-Native Anchorage Blood Cellulitis Immune suppressive therapy Yes 

F 59.6 AK Native Anchorage Peritoneal 

fluid Peritonitis, pneumonia Chronic lung disease, alcohol abuse Yes 

F 62.1 AK Native Other Blood Bacteremia Diabetes Yes 

M 62.4 Non-Native Other Blood Bacteremia Diabetes Yes 

F 62.5 Non-Native Anchorage Blood Cellulitis None Yes 

F 63.7 Non-Native Anchorage Blood Bacteremia None Yes 

M 66.4 Non-Native Anchorage Blood Bacteremia None Yes 

F 68.5 Non-Native Anchorage Blood Cellulitis None Yes 

M 69.8 Non-Native Anchorage Blood Cellulitis None Yes 

M 70 Non-Native Anchorage Blood Bacteremia Diabetes Yes 

F 73.1 Non-Native Other Blood Bacteremia Unknown Yes 

F 73..4 Non-Native Anchorage Blood Pneumonia Chronic lung disease No 

F 76.3 Non-Native Anchorage Blood Cellulitis Chronic lung disease, diabetes Yes 

M 76.6 Non-Native Anchorage Blood Endocarditis None Yes 

M 76.9 Non-Native Other Blood Cellulitis, osteomyelitis Diabetes Yes 

F 80.1 Unknown Anchorage Blood Bacteremia Diabetes Yes 

F 81.9 AK Native Anchorage Blood Pneumonia Chronic lung disease, diabetes Yes 

M 82.7 AK Native Anchorage Blood Bacteremia None Yes 

M 83.2 Non-Native Other Blood Pneumonia None Yes 

F 84.9 AK Native Other Blood Cellulitis None Yes 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 33 

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, 2013.

[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, 2013. 

[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, 2013. 

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

Report, Emerging Infections Program Network, Group A Streptococcus, 2013. 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 34 

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

Report, Emerging Infections Program Network, Group B Streptococcus, 2013. 
Surveillance of Invasive Bacterial Disease in Alaska, 2013 35 

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.