Isolation and Antibiotic Susceptibility Pattern of Bacteria Associated with Blood Stream Infections

Aim: To determine the pattern of bacterial agents responsible for blood stream infection and determine the antibiotic susceptibility pattern of the bacterial isolates.

Study Design: Experimental

Place and Duration of Study: blood samples were collected from general out patient clinic of the University College Hospital, Ibadan, Oyo-State, Nigeria between February 2013 July 2010.

Methodology: The study population was drawn from patients attending the General Out patient clinic of the University College Hospital, Ibadan, Oyo-State, Nigeria. Total blood samples of One hundred and fourty (140) were collected from adultsand children. Samples were immediately dispensed into blood culture bottles and incubated at 37ºC for six days. On the bottles were indicated Name, Age, Sex,and Time of collection. The samples were analysed, all the patientshad clinical evidence of varying degree of illness such as ferbrile illiness, sepsis, bilateral discharge, head injury, endocarditis, pyrexia, gastroenteritis, pneumonia, and poorly treated pnuemonia.Those patients who have been on antibiotics therapy were excluded from the study.

Results: from 140 samples collected, only 100 samples showed turbidityindicating an incidence rate of71.43%. When plated on blood agar, 60 showed microbial growth, 35 samples showed no growth and 5 were contaminated. The difference in prevalence among different sex groups was observed to be significant. The females (77/140, 55%) appeared to be more susceptible to blood stream infection than the males (66/140, 47.1%) in all the age groups. The commonest pathogenic bacteria in blood stream infection was seen to be Staphylococcus aureus having the highest frequency of 58.3%, while Pseudomonas aeruginosa was the least with the frequency of 1.7%. The bacteria harvested were subjected to In-vitro antibiotic susceptibility test using standardized disc agar diffusion methodand showed resistance to one or more of the ten (10) antibiotics used for the study.The lowest resistance of 40% and 60% (36 out of 60) sensitivity was observed in the organisms to Ofloxacin and amoxicillin. Conversely, the highest resistance of 85% (51 out of 60) and 15% (9 out of 60) was observed with Cefuroxime and Erythromycin. However some of the S. aureus (6) and E.coli (3) strains were multidrug resistance.

Conclusion: The study confirmed the diverse nature of bacteria causing blood stream infection and the increase in drug-resistant pathogens needs to be periodically reviewed for epidemiologically data and clinical prescription.