Bacteriological profile and antimicrobial resistance of blood culture isolates from a university hospital

Abstract

Context: Blood stream infections are an important cause of mortality and morbidity and are among the most common health-care associated infections. Illness associated with blood stream infection ranges from self-limiting infections to life-threatening sepsis that require rapid and aggressive antimicrobial treatment. Aims: The objective of the study was to describe the pattern of bacterial isolates from the blood cultures in a university hospital and determine their antibiotic resistance, so that the study can provide guidelines for choosing an effective antibiotic therapy in cases of septicaemia. Settings and design: This is a retrospective study of 2,400 blood samples collected from clinically suspected cases of bacteraemia reviewed over a period of 2 years. Methods and material: The isolates were identified by standard biochemical tests and antimicrobial susceptibility testing determined by National Committee for Clinical Laboratory Standards (NCCLS) guidelines. Results: Positive cultures were obtained in 493 (20.5%) cases. Among culture positive isolates, Gram-negative bacteria accounted for 67.5% cases; most common being Pseudomonas spp. (16%) followed by Salmonella typhi and S. paratyphi A (14.2%). Of the pathogenic Gram-positive isolates, Staphylococcus aureus (8.3%) was the predominant isolate followed by Enterococcus faecalis (3.7%). Maximum Gram-negative isolates were sensitive to cefoperazone-sulbactam combination (81%). Vancomycin sensitivity was reported in 100% Staph. aureus and 83.3% Enterococcus faecalis. Conclusions: This study provides information on antibiotic resistance of blood isolates. It may be a useful guide for physicians initiating empiric therapy and will help in formulation of antibiotic therapy strategy in this part of the country.