Extended-spectrum beta-lactamases producing extensively drug-resistant Salmonella Typhi in Punjab, Pakistan.

Muhammad Saeed,Afreenish Amir,Saba Tariq,Mohsin Khurshid,Farhan Rasheed,Ambreen Anwar Imran,Aamer Ikram,Muhammad Atif Nisar,Muhammad Hidayat Rasool,Muhammad Saqalein

doi:10.3855/jidc.12049

Abstract

The multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates have been increasingly reported from the Asian and African countries. The emergence of isolates with decreased susceptibility to fluoroquinolones and cephalosporins has worsened the situation. Recently, an outbreak from Sindh, Pakistan was reported caused by extensively drug-resistant (XDR) S. Typhi strains. In the present study, a total of 82 cases of typhoid have been investigated during 2018 from the febrile children referred to a tertiary care hospital in the population-wise largest province (Punjab) of Pakistan. S. Typhi was identified by standard microbiological techniques and isolates were characterized for antimicrobial resistance profiling and minimum inhibitory concentrations were determined. The presence of various ESBL genes in S. Typhi was confirmed by the PCR. Out of the 82 isolates tested, 35 (43%) were found to be XDR; resistant to the first-line drugs. The resistance to third-generation cephalosporins was mainly mediated by extended-spectrum beta-lactamases i.e. blaTEM and blaCTX-M genes. The higher prevalence of ESBL producing Salmonella typhi clinical strains raises the concern about transmission prevention and infection management in the community as well as clinical settings. Moreover, the study highlights the problem concerning the declining antibiotic arsenal for the therapeutic management of typhoid fever and the emergence and spread of XDR strains in Pakistan.

Highlights

The multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates have been increasingly reported from the Asian and African countries
The third-generation cephalosporins are being used for the management of typhoid fever especially in the absence of other options; sporadic cases and outbreaks of cephalosporin-resistant S
We report the emergence of extensively drug-resistant (XDR) isolates obtained from the blood cultures obtained from these febrile children and have delineated the genetic basis of cephalosporin resistance

Summary

Introduction

The multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates have been increasingly reported from the Asian and African countries. An outbreak from Sindh, Pakistan was reported caused by extensively drug-resistant (XDR) S. The study highlights the problem concerning the declining antibiotic arsenal for the therapeutic management of typhoid fever and the emergence and spread of XDR strains in Pakistan. Typhi strains has been increasingly reported from the low-income as well as middleincome countries. The first-line treatments including the beta-lactams such as ampicillin along with chloramphenicol and co-trimoxazole (trimethoprimsulfamethoxazole) remained effective till the 1970s, the multidrug-resistant (MDR) isolates (showing resistance to first-line drugs) were increasingly being observed [2]. The third-generation cephalosporins are being used for the management of typhoid fever especially in the absence of other options; sporadic cases and outbreaks of cephalosporin-resistant S. Typhi have been reported recently [4]

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