Rare bacterial isolates causing bloodstream infections in Ethiopian patients with cancer

In recent years, saprophytic bacteria have been emerging as potential human pathogens causing life-threatening infections in patients with malignancies. However, evidence is lacking concerning such bacteria, particularly in sub-Saharan countries. This study was designed to determine the spectrum and drug resistance profile of the rare bacterial pathogens causing bloodstream infections (BSIs) in febrile cancer patients at a referral hospital in Ethiopia.

Between December 2011 and June 2012, blood samples were collected from 107 patients with cancer in Tikur Anbessa hospital. Culturing was performed using the blood culture bottles and solid media and the microorganisms were identified using the gram staining and APINE identification kits (Biomerieux, France). The disk diffusion method was used for the antimicrobial susceptibility testing.

Overall, 13 (12.2%) rare human pathogens were isolated from 107 adult febrile cancer patients investigated. Aeromonas hydrophilia species (a fermentative gram-negative rod) was the predominant isolate, 30.8% (4/13), followed by Chryseomonas luteola 15.4% (2/13), Sphignomonas poucimobilis 15.4% (2/13), and Pseudomonas fluorescens 15.4% (2/13). Of the nine isolates tested for a nine set of antibiotics, 89% were resistant to amoxicillin-clavulanic acid, ampicillin, and trimethoprim-sulphamethoxazole.

This study revealed the emergence of saprophytic bacteria as potential drug-resistant nosocomial pathogens in Ethiopian patients with cancer. As these pathogens are ubiquitous in the environment, infection prevention actions should be strengthened in the hospital and early diagnosis and treatment with appropriate antibiotics are warranted for those already infected.