Microbial spectrum and drug-resistance profile of isolates causing bloodstream infections in febrile cancer patients at a referral hospital in Addis Ababa, Ethiopia.

Abstract

BackgroundThe spectrum of pathogens causing bloodstream infections (BSIs) in cancer patients has shown significant fluctuations in different geographical areas and time. We studied the microbial spectrum and drug-resistance profile of pathogens causing BSIs in febrile cancer patients at a referral hospital in Ethiopia.MethodsThis cross-sectional study was conducted between December 2011 and June 2012 at Tikur Anbessa Hospital in Addis Ababa. Blood cultures from febrile cancer patients (n=107) were performed. Bacterial and fungal pathogens were identified and antimicrobial susceptibility testing done for the bacterial isolates using the Kirby–Bauer disk diffusion method.ResultsA total of 82 pathogens were isolated from 112 blood culture tests of the 76 patients: 71 (86.6%) of the isolates were bacteria and 11 (13.4%) were fungi. The majority (60.5% [43 of 71]) of the isolates were Gram-positive bacteria, where Staphylococcus aureus was predominant (72% [31 of 43]), and 68% of S. aureus isolates were resistant to ceftriaxone and oxacillin. Gram-negative bacteria accounted for 39.5% (28 of 71) of the isolates. Stenotrophomonas maltophilia (17.9% [five of 28]) was the most frequent Gram-negative isolate. In Gram-negative bacteria, the highest rates of resistance were observed in amoxicillin–clavulanic acid (80% [12 of 15]), followed by ceftriaxone (73.3%) and trimethoprim–sulfamethoxazole (73.3%). Multidrug resistance (resistance to three or more types of antibiotics, in this case to ceftriaxone, tetracycline, and trimethoprim-sulfamethoxazole) was observed in 26.3% (13 of 43) of Gram-positive and 40% (six of 16) of Gram-negative bacteria. Neutropenia was an independent risk factor for BSIs (P=0.02).ConclusionGram-positive bacteria were the predominant etiologic agents of BSIs in Ethiopian patients with cancer. Both Gram-positive and Gram-negative bacteria showed an increasing level of resistance for most of the antibiotics used for empiric therapy. Routine bacterial surveillance and study of their resistance patterns must be an essential component of cancer-related infection control and care in our setting.