Bacterial Isolates from Blood Samples of Patients in University of Benin Teaching Hospital Benin City, Edo State, Nigeria.

Abstract

The presence of bacteria in the blood stream results in a condition known as bacteremia. This condition is associated with pyrexia of unknown origin (PUO). The study seeks to determine the bacterial etiology of bloodstream infections and their susceptibility profile in a tertiary healthcare institution. The design was prospective and crosssectional. Specimens were obtained from patients in no particular selection order except that they were consecutively obtained. The study was carried out in a tertiary healthcare institution which is equipped with a standard microbiology laboratory. Patients seen at the various facilities in the hospital were used for the study. They numbered one thousand, six hundred and seventy (1,670) patients. This was during the period October 2008 to September 2009. The patient population was 1,500 (89.2%) infants while adults were 170 (10.8%). 1ml of venous blood was aseptically inoculated into two blood culture bottles, brain heart infusion broth and thioglycollate broth while giving great attention to sterile process. They were incubated overnight at 37 C and were examined daily for growth. Growth is usually characterized by gas bubbles or turbidity. If there was indication of growth either in the brain-heart infusion broth or the thioglycollate broth or both; gram staining and microscopy were prepared and read. The thioglychollate broth was sub cultured onto blood agar plate for anaerobic incubation, while the brain heart infusion broth was sub cultured onto chocolate, blood agar and McConkey agar for aerobic incubation. The anaerobic incubation was done by putting the culture plates into an anaerobic jar and filling it with hydrogen gas. This was incubated at 37 C overnight. The organisms isolated were identified to species level using the protocol of Cowan and Steel. The antibiotic susceptibility spectrum of the isolates was determined using the agar diffusion method of Bauer and Kirby. Eleven bacterial species were isolated in the study and they varied widely in their antibiotic susceptibilities. Ofloxacin exhibited the highest antimicrobial activity. Staphylococcus aureus was 56.3% susceptible to oxacillin. The study isolated the common bacteria involved in bacteremia and determined their susceptibility profile, and also suggested some control measures.

Keywords: Bacteremia; Pyrexia of unknown origin; antibiotic susceptibilities,