Characterization of TEM-Mediated Ampicillin Resistance in Salmonella typhi Isolates of Pakistan "

Abstract

 Typhoid fever or Salmonellosis is a systemic disease caused by the Gram-negative pathogen Salmonella typhi. It is still a serious problem in most of the third world countries. Many antibacterial drugs are being used for its treatment, but emergence of drug-resistant strains has prompted scientists worldwide to opt for an alternative approach. For this reason, we characterized the resistant strains, so as to determine their pattern of resistance to antibiotics. Fifty seven (57) multidrug-resistant (MDR) S. typhi were isolated from 200 blood samples obtained from patients with typhoid fever. Minimum Inhibitory Concentration (MIC) was determined against Ampicillin, Sulfamethoxazole, Ofloxacin, Chloramphenicol and Streptomycin. Plasmid profiling was done and analyzed by gel electrophoresis. PCR of 848 bp region in TEM gene was performed to check the presence of Extended Spectrum β-Lactamase (ESBL) gene. Five out of nine (55.6%) isolates were found positive for ESBL. Research for characterizing ESBL isolates in different pathogenic bacteria is going on globally. This character cannot only be transferred to other bacteria through conjugation, but also using conventional drugs may lead to the development of new resistant strains