Multidrug resistant Salmonella typhi in Delhi

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Typhoid fever, caused by Salmonella typhi, remains a significant global health concern.
• The emergence of multidrug-resistant (MDR) Salmonella typhi strains poses a substantial challenge to effective treatment.
• Understanding resistance patterns is crucial for guiding antimicrobial therapy and public health strategies.

Purpose of the Study:

• To investigate the prevalence of multidrug resistance in Salmonella typhi isolates from typhoid fever patients.
• To determine the susceptibility profiles of resistant strains to a range of commonly used and newer antibiotics.

Main Methods:

• Isolation and identification of Salmonella typhi from blood cultures of patients diagnosed with typhoid fever.
• Antimicrobial susceptibility testing using standard microbiological methods.
• Determination of minimum inhibitory concentrations (MICs) for key antibiotics.

Main Results:

• Out of 158 Salmonella typhi isolates, 79 (50%) exhibited simultaneous resistance to chloramphenicol, ampicillin, and cotrimoxazole.
• These MDR strains were also resistant to streptomycin and tetracycline but remained sensitive to gentamicin, amikacin, and cephalexin.
• High minimum inhibitory concentrations (MICs) were observed for chloramphenicol (>1024 µg/ml) and trimethoprim (>128 µg/ml).
• A majority of MDR strains showed sensitivity to cefotaxime, ciprofloxacin, and amoxicillin-clavulanic acid.

Conclusions:

• A significant proportion of Salmonella typhi isolates in 1990 displayed multidrug resistance, highlighting a growing public health threat.
• While resistance to older antibiotics is prevalent, newer agents like ciprofloxacin and cefotaxime show promise for treating MDR typhoid fever.
• Continued surveillance of antimicrobial resistance patterns is essential for effective management of typhoid fever.