Study of frequency of bacteria isolated from blood culture and their antibiotic susceptibility pattern in a university hospital in Tehran

Determining frequency of bacteria, isolated from blood culture and their antibiotic susceptibility patterns, has epidemiological significance and can help in selecting empirical therapy. This study was aimed to assess, the frequency of bacteria isolated from blood culture of patients suspected to bacteremia and their antibiotic susceptibility patterns. Culture of blood and determination of antibiotic susceptibility was done by standard methods. In this study, a variety of isolated bacteria types, antibiotic susceptibility, as well as age, sex and type of admission of patients were analyzed in a university hospital from 21 March, 2006 to 20 March, 2007. During one year, blood culture was done for 5116 patients and bacteria were isolated in 912 cases (17.8%). Three most frequently groups of bacteria in blood cultures of patients were non-fermentative gram negative bacteria (Pseudomonas and Acintobacter spp), coliforms (Escherichia coli and enterobacter and klebsiella spp.) and coagulase negative staphylococci, respectively, which were isolated in 63.4%, 17.0% and 12.8% of patients, and constituted 93.2% of positive blood cultures. Higher resistance was shown in bacteria isolated from inpatients compare to outpatients. This study showed the influence of age, sex and type of admission (outpatient or inpatient) in a variety of isolated bacteria in blood culture. The result of this study were the same as the other studies in Iran and other countries in respect of the variety of isolated bacteria and antibiotic susceptibility and show increase of antibiotic resistance in these bacteria.