14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
is available electronically on http://www.sciencedirect.com
Final Abstract Number: 23.015
Session: Antibiotic Resistance Gram-Negative
Date: Wednesday, March 10, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
Antimicrobial resistance in non-typhoidal Salmonellae
B. Harish 1 , M. Khan 2 , J. Hays 3 , G. Menezes 4
1 Jawaharlal Institute of Postgradute Medical Education & Research (JIPMER), Pondicherry, India,
2 Erasmus MC, ROTTERDAM, Netherlands, 3 Erasmus MC, Rotterdam, Netherlands, 4 Jawaharlal
Institute of Postgraduate Medical education and Research (JIPMER), Pondicherry, India
Background: Non-typhoidal salmonellae are among the primary causes of food-borne
gastroenteritis worldwide. Treatment failures due to the in-vivo acquisition ESBL gene or
fluoroquinolone resistance in these bacteria are well documented, particularly in India, though
actual molecular information is currently lacking. In this study we investigated ESBL genes, and
fluoroquinolone resistance in non-typhoidal salmonellae isolated.
Methods: 23 isolates of non-typhoidal salmonellae were collected. Isolates were identified
biochemically and agglutination, with antibiotic profiles being obtained. PCR and sequencing
were used to determine the genetic determinants of antibiotic resistance. Isolates were screened
for qnr gene and integrons by PCR, and plasmid analysis was performed using PCR-based
replicon typing. Crude extracts of -lactamase were subjected to isolelectric focussing and the
role of efflux pumps in fluoroquinolone resitance was also studied. Isolates were genotyped
using PFGE and ERIC-PCR.
Results: Six different Salmonella serovars were identified, the majority being S. Agona (48%),
with one of the S. Agona isolates being unusually positive for a combination of TEM-1, SHV-12,
OXA-1-like and DHA-1 genes. Twelve isolates (49%) were phenotypically ESBL producers, with
12, 11, 3, 2 and 1 of these isolates being TEM-1, SHV-12, DHA-1, OXA-1-like and CTX-M-15
gene postive, respectively. Four out of these 12 ESBL positive isolates were also resistant to
fluorquinolones with 3 out of 4 possessing double mutations in the gyrA gene. No mutations were
detected in the gyrB and parE genes of these 12 isolates. Inc/rep typing detected the presence of
FIIS replicons in the majority of isolates. Phenotypic evidence for efflux pumps was detected in 4
isolates. Eight of the isolates were positive for integrons. Genotypic diversity was observed
among the isolates, even within isolates from the same hospital.
Conclusion: Twelve of 23 (52.2%), a very high proportion of non-typhoidal salmonellae from
India produced ESBLs. The SHV-12 ESBL is one of the most common non-CTX-M ESBLs and is
identified in many Gram-negative species, including Salmonella species. Our study confirms the
role of double mutation in gyrA combined with 1 or 2 mutations in the parC and efflux
mechanisms in conferring high resistance to ciprofloxacin. In India, non-typhoidal salmonellae
constitute approximately 20% of the Salmonella serovars and continued surveillance for the
presence of new ESBLs and fluoroquinolone resistances is required in India.