Investigation of Antimicrobial Susceptibilities Among Bacteria Isolated from Blood Cultures in Hospitalized Patients, Tehran, Iran

Background: Bacteremia is the status, which is detected via a positive blood culture test with no contamination. Centers for Disease Control and Prevention (CDC) indicates that direct medical procedures and total costs are significantly high. Antibiotic resistance can play a major role in the costs, which are related to the long duration of treatment. Objectives: The aim of this study was to investigate the rate and profiles of antimicrobial susceptibility of blood culture isolates from Tehran, Iran. Methods: In the current cross-sectional study, a total of 5,000 blood culture samples were collected from patients hospitalized in the Loghman General Hospital, Tehran, Iran, with positive blood culture results from 2012 to 2013. Susceptibility to antimicrobial agents was analyzed using National Committee for Clinical Laboratory Standards guidelines. Results: Coagulase-negative staphylococci (38.8%), Staphylococcus aureus (20.5%), Acinetobacter (11.9%), and Escherichia coli (11.7%) were the most frequent bacteria isolated from the blood cultures, collectively accounting for > 80% of the isolates. Of isolated microorganisms, 63.75% and 36.24% belonged to Gram-positive and Gram-negative bacteria, respectively. Moreover, 88% of the isolates were MRSA (oxacillin-/methicillin-resistant), and 7% were VRE (vancomycin-resistant). Conclusions: The most frequent isolated organisms were Gram-positive bacteria, and the rate of MDR (multi-drug resistance) was high. The results of the current study obviously indicate the misuse of antibiotic in society. National surveillance studies in Iran will be useful for clinicians to choose the right empirical treatment and will help control and prevent infections caused by resistant organisms.