Jpn, J. Infect. Dis., 55, 45‑46, 2002

Short Communication

Antibiotic SusceptibilityPatternof Salmonella worthington
Isolated from Neonates ‑ a Retrospective Study
DnyaneshwariP. Ghadage and Abhijit M. Bal*
Department ofMicrobioloBy, B.JMedical College, Sassoon Road, Pune 411 001, India(Received December 27, 2001. Accepted March 18, 2002)
SUMMARY: Salmonella worthington is an emerglng Pathogen and has been imphcated in a number of outbreaksof neonatal menlngltlS and septlCemia. Over a period of 5 years, a total of 30 strains of this pathogen wereisolated舟om blood and cerebrosplnal nuid of neonates suffering舟om septicemia with or without menlngltlS･Most of these strains were resistant to the penicillin group of antibiotics, and many were resistant to cefbtaxime･
Sixty percent of the isolates were resistant to amikacin; 86% Were resistant to chloramphenicol, and none wereresistant to clpronoxacin or nornoxacin. Parenteral nuoroqulnOlone should be included as part of antibiotic

therapy ln Suspected cases ofneonatal meningitis due to A worthington.

Salmonella enterica. serovar Worthington (Salmonellazone diameter, the isolates were characterized as sensitive,worthinbqOn) is an emerging Pathogen and has been responsible

intermediate, or resistant. The antibiotic discs (Hi‑Mediafor hospital associated outbreaks in nursery tmits ( 1 ,2). SuchLaboratories, Pune, India) usedincluded ampicillin, amoxicillin,

infections are characterized by a highmortalityrate due tocefotaxime, chloramphenicol, amikacin, cIPrOnOXaCln, andthe neonatal immune system, which is notfully developed

nornoxacin in all 30 cases, and onoxacin in 14 cases.

and to the emergence of multidrug resistance among strains

S. worthington was isolated A.om blood samples in 1 9 cases,of nontyphoidal Salmonellae. We conducted a retrospective斤om CSF samples in丘Ve cases and舟om both blood and CSF

study to determine the antibiotic sensitivity PatternOf S.

in six cases. The results of the antibiotic sensitivity pattems

worthington strains isolated &om neonates kom 1 995 to 2000.

are sumarized in Table 1.

Knowledge of the antibiotic sensitivitypatternwill be use免11

Neonatal infection due to S. worthington can clinicallyto the formulation of guidelines regarding empirical therapy

present as diarrhea, septicemia, jaundice, of meningitis ( 1 ,2,5)･

befわre drug sensitivity reports are available, and will thus

The source of infection is essentially environmental, and theorganism has been isolated &om baby cots, warmer mattresses

contribute to better patient management.
Samples from a total of 752 cases of suspected neonatal

and therubber tubing of the suction apparatus stationed in

septicemia were subjected to bacteriologlCal examination overneonatal intensive care units (2,5). ln earlier reports fromthe 5‑year period. Strains of S. worthington were isolated

India, strains were found to be resistant to multiple antibiotics,&om 30 (3.9%) cases ofneonatal septicemia with or without

and were associated with a highmortalityrate (6). Microbio‑

menlngitis. This included strains isolated舟om sporadic cases

logical assessment ofinvitro sensitivityoRen takes 48 h舟om

and from two outbreaks. Blood and/or cerebrosplnal nuid

the time of collection of samples, and empirical therapy needs(CSF) samples were subjected to standard bacteriOlogicalto be instituted befわre the sensitivity reports are obtained.

methods fb∫ isolation and ident捕cation of patbogens (3).

Prior knowledge of the sensitivitypattem of pathogenic

Antibiotic sensitivity was detemined using the Kirby‑Ba°er

bacteriawill facilitate early institution of therapy to which

disc di軌sion method according to the guidelines set by thethe organisms are likely to be sensitive.

National Center for Clinical Laboratory Standards (NCCLS),
using standard American Type Culture Collection (ATCC)

Our results showed that most isolates of S. worthington
were resistant to ampicillinand amoxicillin. Nineteen out of 30

strainswith every batch of tests as described (4). Based on the(63%) isolates were resistant to cefbtaxime; six (20%) oftbe

Table 1. The antibiotic resistance (%) ofisolates ofS. worthinglon
SampleBloodNllmber
1AAmCeC

8 0 09 0 07005 ′LU OO 8 0 3

Cp(リノ 0 0

Oノ 0 ′04 ′LU 0｢1CSF

1 11 1

Blood and CSF
Tota IAk(XU O ′0ny 0 00ノ 5 ′013086

93638660000A, AlllPicillin; Am, Amoxicillin; Ce, Cefbtaxime; C, Chloramphenicol; Ak, Amikacin; Cp, Cipronoxacin;
N, Norfloxacin; 0, 0割oxacin; NT, Not Tested.
lOfloxacin was tested in 12 out of 1 9 isolates斤om blood and 2 out of5 isolates舟om cerebrosplnal f一uid(CSF).

*Corresponding author: Mailing address: 47/A Ideal Colony,
Radheya Apartments, Flat‑2, Kothrud, Pune, Maharashtra, India.
Tel:十9 1‑20‑54683 1 1 , E一mai1: balabhijit@rediffhlail,com

45

remaining 1 1 were sensitive, and丘ve (1 7%) had zone diameters

ACKNOWLEDGMENTS

in the intemediate range. The叩pearanCe Of cephalosporin‑

resistant nontyphoidal Salmonellae is a matter of concem. lnWe thank the Central Research Institute, Kasauli, foraddition, a novel cefotaximase, CTX‑2, has recently been
demonstrated in S. mbandaka (7). Resistance to cefotaxime

confirmation of the Salmonella serotype, and the Dean ofB,J. Medical College for providing the necessary facilities.

also indicates resistance to ceftriaxone and ceftizoxime,

further limiting the therapeutic choice (4). In our study, 18REFERENCES

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