Aerobic Bacteriological Profile of Bloodstream Infections with Special Reference to ESBL Producers among the Gram Negative Isolates

Abstract

Background: Bloodstream infections (BSI) refer to the presence of microorganisms in blood.  The timely detection and identification of pathogens of bloodstream infection and determination of antibiotic sensitivity has great diagnostic and prognostic importance. Aim: To study the aerobic bacteriological profile of bloodstream infections, to determine their antibiotic susceptibility pattern and to find out the proportion of ESBL producers among the gram negative isolates. Materials and Method: This descriptive cross-sectional study included 950 blood samples received for culture in the Microbiology laboratory, from inpatients of Government Medical College, Ernakulam. Isolates obtained were identified and ABST done as per standard protocols. For all GNB, ESBL production was detected by phenotypic method as per CLSI guidelines. Genotyping for ESBL gene detection was also done for Enterobacteriaceae isolates. The data entered in excel spread sheet was analysed using Statistical Package for Social Sciences (SPSS) software 20.0. Fisher’s exact test was used in the analysis of study variables. The level of statistical significance was taken as p value < 0.05. Result: The culture positivity rate was 6.5%. 74% of the isolates were gram negative bacilli. Escherichia coli was the most frequent organism isolated, followed by Staphylococcus aureus. 39.1% of the gram negative isolates were ESBL producers and majority of them were E. coli. The most prevalent beta-lactamase gene detected was bla_CTX-M. Conclusion: We could prove statistically significant association of presence of invasive device for more than 1 week with both bloodstream infections and ESBL production. We could also prove statistically significant association of ESBL production with group of antibiotic used currently.

Keywords: Bloodstream infection; ESBL