Detection of blaCTX-M Extended Spectrum Beta-lactamase Producing Salmonella enterica Serotype Typhi in a Tertiary Care Centre
Introduction: Infections caused by Salmonella are an important public health threat in tropical and subtropical countries. Due to the emergence of resistance to ampicillin, chloramphenicol and trimethoprim/sulfamethoxazole (multidrug resistant salmonellae) in the late 1980s, fluoroquinolones and...
Main Authors: | , , |
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Format: | Article |
Language: | English |
Published: |
JCDR Research and Publications Private Limited
2017-09-01
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Series: | Journal of Clinical and Diagnostic Research |
Subjects: | |
Online Access: | https://jcdr.net/articles/PDF/10637/30150_160917_30150_CE(RA1)_F(T)PF1_(BI_VJ_PY)_PFA(NC_VJ_AP).pdf |
Summary: | Introduction: Infections caused by Salmonella are an important
public health threat in tropical and subtropical countries. Due to
the emergence of resistance to ampicillin, chloramphenicol and
trimethoprim/sulfamethoxazole (multidrug resistant salmonellae)
in the late 1980s, fluoroquinolones and extended spectrum
cephalosporins became the drugs of choice. Resistance to
cefotaxime and ceftriaxone due to the production of Extended
Spectrum Beta-Lactamase (ESBL) and reduced susceptibility
to ciprofloxacin have emerged resulting in treatment failure. The
Cefotaximase (CTX-M) type ESBLs are the most widespread beta
lactamase among Enterobacteriaceae including salmonellae.
Aim: To detect the presence of blaCTX-M in salmonellae causing
human infections. Detection of qnr genes to identify the
coexistence of blaCTX-M and qnr gene.
Materials and Methods: The study included 103 consecutive,
non-repetitive salmonellae isolated from clinical specimens
obtained from July 2015- June 2016 which were identified up to
species level by conventional/automated methods. Susceptibility
to various classes of antimicrobial agents was determined
by disc diffusion method. Minimum Inhibitory Concentration
(MIC) to cefotaxime and ceftriaxone was determined by agar
dilution method. The results were interpreted in accordance
with Clinical & Laboratory Standard Institute (CLSI) (guidelines
2015. Detection of the ESBL phenotype was performed by the
combined disk method. Polymerase Chain Reaction (PCR)
amplification of all isolates was performed using group specific
primers to characterize the presence of blaCTX-M, qnrA, qnrB and
qnrS.
Result: Of the 103 study isolates two isolates of Salmonella typhi
were resistant to cefotaxime and ceftriaxone and had a MIC
of 128µg/ml. PCR amplification and sequencing detected the
presence of blaCTX-M-15 in these two isolates. These two isolates
exhibited resistance to ciprofloxacin in vitro but qnr gene was
not detected in these isolates.
Conclusion: Resistance to third generation cephalosporins
among salmonellae is a cause for concern as it may lead to
treatment failure. It is imperative to continuously monitor the
susceptibility pattern as enteric fever is endemic in India. |
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ISSN: | 2249-782X 0973-709X |