FREQUENCY AND ANTIMICROBIAL RESISTANCE PATTERN OF SALMONELLA TYPHI ISOLATED FROM BLOOD CULTURES

Abstract

Background:

Enteric fever spread worldwide by Salmonella typhi (S. typhi). The causative agent, S. typhi is gram negative bacilli belongs to the family Enterobacteriaceae. It is a motile, facultative anaerobic bacilli. Multi-drug resistant (MDR) S. typhi is being accepted as most challenging enteric pathogen in developing countries like Pakistan. The accurate diagnosis of S. typhi is vital for treatment. This study evaluates frequency of S. typhi in blood cultures and antibiotic resistance against S. typhi. The study assist physician to decide better antimicrobial option to treat patients and also update resistant pattern of S. typhi. The aim of this study was to determine the frequency and antibiotic resistance pattern of Salmonella typhi isolated in blood cultures at tertiary care hospital laboratory.

Methodology:

All Blood culture samples were received from febrile patients. An automated machine, BACTEC 9240 were used for blood culture processing. Identification of S. typhi from positive cultures were done by the help of gram stain, colony morphology, biochemical tests, and serological testing. Antimicrobial susceptibility testing was performed through Kirby Bauer method on Mueller Hinton agar according to Clinical Laboratory Standard Institute guidelines. Data analysis was completed by using Statistical Package for Social Sciences (SPSS) version-20.

Results:

A total of 16010 samples of blood were cultured for bacterial isolation, Out of these, 411 (2.56%) turned out to be positive for S. typhi while 193 Isolates were MDR strains and 218 isolates were Non-MDR strains. None of the MDR strains were resistant to cefixime, ceftriaxone and aztreonam .

Conclusion:

This study indicated that resistance in S. typhi is progressively high against first line drugs which draw attention towards monitoring of antimicrobial resistance. Rational use of antimicrobials should be implemented on the basis of culture and sensitivity results.