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

Introduction: 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. Methodology: 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. Results: 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. Conclusions: 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.

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Emerging Trends of Multidrug-Resistant (MDR) and Extensively Drug-Resistant (XDR) Salmonella Typhi in a Tertiary Care Hospital of Lahore, Pakistan

Microorganisms ◽

10.3390/microorganisms9122484 ◽

2021 ◽

Vol 9 (12) ◽

pp. 2484

Author(s):

Muhammad Zakir ◽

Maryam Khan ◽

Muhammad Ihtisham Umar ◽

Ghulam Murtaza ◽

Muhammad Ashraf ◽

...

Keyword(s):

Disease Burden ◽

Tertiary Care ◽

Salmonella Typhi ◽

Multidrug Resistant ◽

Care Hospital ◽

Drug Resistant ◽

Extensively Drug Resistant ◽

Emerging Trends ◽

Antibiotic Susceptibility Test ◽

Resistant Strains

Salmonella Typhi is a Gram-negative pathogen that causes typhoid fever in humans. The use of antibiotics to treat typhoid has considerably mitigated its fatality risk, but rising multidrug-resistant (MDR) and extensively drug-resistant (XDR) resistance in Pakistan threatens effective treatment. This study determined the prevalence of MDR and XDR S. Typhi at a local hospital in Lahore. Blood samples (n = 3000) were obtained and processed for bacterial identification. Antibiotic susceptibility test was performed using VITEK® 2 Compound 30 System. Statistical data analysis was performed using a Mann–Whitney U and Kruskal–Wallis H test, respectively. The results revealed 600 positive cultures, of which the majority were found to be XDR S. Typhi (46.1%) and MDR S. Typhi (24.5%) strains. The disease burden of resistant Salmonella strains was greater in males (60.67%) than females (39.33%), with the most affected age group being 0–10 years old (70.4 %). In both the outpatient department (OPD) and general ward, the prevalence of XDR S. Typhi cases was found to be alarmingly high (48.24%), followed by MDR S. Typhi (25.04 %). The results of the statistical analysis demonstrated that the incidence of resistance in MDR and XDR S. Typhi strains was not affected by the age as well as the gender of patients (p > 0.05). The occurrence of resistant strains against four tested antibiotics (azithromycin, ciprofloxacin, imipenem, and meropenem) was found to be similar in different wards and among hospitalized and OPD patients (p > 0.05). Maximum resistance was observed against chloramphenicol and ampicillin in the OPD and pediatric ward. Piperacillin/Tazobactam was observed to be the most effective antibiotic, followed by co-amoxiclav (p < 0.001). This study is effective in validating the existence of MDR and XDR S. Typhi in Lahore, where stringent methods should be applied for controlling its spread.

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