Bacterial isolates in neutropenic febrile patients

One hundred consecutive patients with documented bacteremia and neutrophil count of 0.5 x 10(9)/L or below were retrospectively studied to determine the pattern of infection at the Aga Khan University Hospital in Karachi. These included patients with primary haematologic malignancies presenting with low counts, and those patients with cancer who developed neutropenia as a result of chemotherapy. The gram negative organism pseudomonas aeruginosa was the most common bacterial organism isolated constituting 31% of all positive blood cultures. Gram positive organisms were frequently isolated comprising 24% of all isolates of which 15% were Staph.aureus. Staph. epidermidis was not isolated in this series. Salmonella species were isolated in 9 patients. The other gram negative rods included non-lactose fermenting organisms frequently isolated in a nosocomial setting including Serratia and Acinetobacter. Four patients had positive fungal blood cultures. A single positive anaerobic culture was obtained. Sensitivities of the Pseudomonas aeruginosa reflected the high frequency of resistance seen in nosocomial isolates and those from the community. More than half (54.8%) of the isolates were resistant to carbenicillin and 9.6% resistant to gentamicin. Although 3.2% were resistant to cefotaxime, none were resistant to ofloxacin or ceftazidime reflecting the relatively recent arrival of the latter. In contrast, 23% of Staph. aureus were still sensitive to penicillin. Methicillin (cloxacillin) resistant Staph. aureus did not occur. However 26.6% of the Staph. aureus were resistant to erythromycin. Knowledge of the prevailing pattern of infection permits the development of investigative and therapeutic approaches of optimal efficacy.