Rapid detection of ceftriaxone resistance in clinical isolates of extensively drug resistant Salmonella enterica serovar Typhi.

OBJECTIVE: To see the efficacy of rapid colour test for the sensitivity of ceftriaxone against clinical isolates of salmonella typhi. METHODS: The cross-sectional validation study was conducted at the Department of Microbiology, Pakistan Navy Ship Shifa Hospital, Karachi, from Nov 2018 to April 2019, and comprised clinical isolates of salmonella typhi that were obtained from five different hospitals in Karachi and Hyderabad. The isolates were tested using the rapid colour test. All the isolates were also tested using the conventional disc diffusion method and minimum inhibitory concentrations on the Vitek-2 version 8.01. RESULTS: Of the 97 isolates, 83(85.5%) were ceftriaxone-resistant and 14(14.4%) were ceftriaxone-sensitive. Sensitivity and specificity of the rapid colour test were 100% when compared with the results of the other methods. All the results were readable within 2 hours on the colour test. CONCLUSIONS: The colour test was found to be a rapid, accurate and inexpensive tool to screen for ceftriaxone resistance in typhoid-endemic areas.

Typhoidal Salmonella strains in Pakistan: an impending threat of extensively drug-resistant Salmonella Typhi.

The aim of this study is to see the frequency, clinical presentation, and therapeutic response of extensively drug-resistant Salmonella enterica serovar Typhi and current susceptibility pattern of typhoidal Salmonella strains in our setup. This study was carried out at the Department of Medical Microbiology and Immunology and Department of Medicine, Pakistan Navy Ship (PNS) Shifa Hospital, Karachi, from January 1 to December 31, 2018. All the blood culture samples of patients (indoor and outdoor) with suspicion of enteric fever were processed. Isolates were cultured and identified using standard microbiological procedures. The antimicrobial sensitivity against the typhoidal Salmonellae was determined using Kirby-Bauer disc diffusion method as per the guidelines of Clinical and Laboratory Standards Institute (2018) and all the extensively drug-resistant (XDR) isolates were confirmed by Vitek 2 system. Clinical presentation and response to treatment of patients were followed. A total of 292 typhoidal Salmonella isolates were cultured. Resistance to ciprofloxacin against both Salmonella Typhi and Salmonella Paratyphi A was found to be very high (91%). Percentage of multidrug-resistant (MDR) isolates in Salmonella Typhi was 76% (182 isolates) and in Salmonella Paratyphi it was 34% (18 isolates). XDR isolates in Salmonella Typhi were significant that is 48% (115 isolates). Only 10 cases were given azithromycin who responded to treatment in mean 4.3 days. Out of 115 cases of XDR Salmonella Typhi, 103 patients were given parenteral meropenem and clinical response was seen in mean 5 days. The emergence and rapid spread of extensively drug-resistant Salmonella Typhi is alarming and highlights the significance of strict antimicrobial susceptibility surveillance programs with antimicrobial stewardship.

Current Trends of Antimicrobial Susceptibility of Typhoidal Salmonellae Isolated at Tertiary Care Hospital.

OBJECTIVE: To determine the current trend of antimicrobial susceptibility of typhoidal Salmonellae. STUDY DESIGN: Descriptive cross-sectional study. PLACE AND DURATION OF STUDY: The study was carried out in the Department of Microbiology, PNS Shifa Hospital, Karachi, from January 2014 to December 2015. METHODOLOGY: Blood culture samples received from the wards and outpatient departments were included. Isolates of Salmonella were dealt with standard microbiological procedures. The antimicrobial sensitivity against the typhoidal Salmonellaewas determined using Kirby-Bauer disc diffusion method as per the guidelines of Clinical and Laboratory Standards Institute (2013). RESULTS: Atotal of 460 typhoidal Salmonellaewere isolated; out of which 270 were Salmonella typhiand 190 were Salmonella paratyphiA. The percentage of MDR isolates of S. typhiwas 57% and that of S. paratyphiAwas 42%. None of the isolates were resistant to ceftriaxone, while sensitivity to ciprofloxacin (07% and 0% for S. typhiand S. paratyphiA, respectively) was very low. CONCLUSION: There is high percentage of MDR isolates of typhoidal Salmonellaein our region. The antimicrobial sensitivity of typhoidal Salmonellaeto conventional agent has not improved enough to recommend their empirical use. There is almost complete resistance to fluoroquinolones as well, leaving very limited available treatment options.