Antibacterial susceptibility patterns of blood stream isolates in patients investigated at the Aga Khan University Hospital, Nairobi.

BACKGROUND

Microbial invasion of the blood stream can have serious immediate consequences and are a threat to every organ in the body. Timely detection and treatment is vital and necessitates hospital admission and immediate intervention.

OBJECTIVES

To investigate aetiology and anti-microbial resistance patterns of bacterial isolates in blood stream infections.

DESIGN

A retrospective clinical-laboratory study carried over a five year period January 2003 to April 2008.

SETTING

The Aga Khan University Hospital, Nairobi, Department of Pathology, Division of Microbiology.

SUBJECTS: All blood culture specimens received from both in and out-patients' at the Aga Khan University Hospital's laboratory.

RESULTS

Rates of oxacillin resistance for Staphylococcus aureus were 21%. Streptococci were generally susceptible to beta-lactams. High-level gentamicin resistance was seen in 12% of Enterococci. Vancomycin resistance was conspicuously absent. Resistance rates of Pseudomonas aeruginosa to ciprofloxacin, gentamicin, amikacin, imipenem were between 11% and 23%. Salmonella spp. showed multiple resistant patterns to co-trimoxazole, chloramphenicol and ampicillin with resistance rates of greater than 35%. One hundred and twenty three patients (11%) tested positive for HIV. Unlike in HIV negative individuals, Cryptococcus neoformans was an important isolate, positive in 5%. A number of HIV positive patients had Staphylococcus aureus and coagulase negative staphylococcus isolates in their blood cultures. In such clinical circumstances it is difficult to determine the clinical significance of these isolates.

CONCLUSION

Antimicrobial susceptibility patterns revealed high level resistance among the gram positive organisms and also amongst extended spectrum beta lactamase (ESBL) producing E.coli and Klebsiella spp. This study highlights the challenges of deriving empiric drug regimens in the current clinical scenario. However, we do know it is important to cover adequately for gram positive organisms.