Microbial spectrum and antibiotic susceptibility profile of Gram-positive aerobic bacteria isolated from cancer patients

Purpose: Cancer patients are particularly susceptible to nosocomial infections because of their compromised immune system, and because of the nature of treatment practices they experience. Recently, a shift of the microbial spectrum of cancer patients from Gram-negative to Gram-positive has been demonstrated. This study analyzed the distribution and the antimicrobial resistance of Gram-positive bacteria isolated from cancer patients in Egypt. Patients and Methods: We examined the microbial spectrum of Gram-positive bacteria in patients with hematologic malignancies and solid tumors. In addition, we also studied the antimicrobial resistance of pathogens accounting for the majority of Gram-positive infections in these cancer patients. Results: Most of Gram-positive isolates from urinary tract (100%), respiratory tract (89.7%), and bloodstream infections (BSIs; 65.5%) were obtained from leukemic patients. All Gram-positive isolates from skin infections were isolated from solid-tumor patients. In both leukemic and solid-tumor patients, Gram-positive bacteria causing nosocomial BSI were mainly Coagulase-negative staphylococcus (CNS) and S aureus, whereas Gram-positive bacteria causing nosocomial RTI were mainly α-hemolytic streptococci and CNS. Gram-positive bacteria were not isolated from GI tract infections. S aureus, CNS, and α-hemolytic streptococci demonstrated methicillin resistance (81.5%, 92.3%, and 90% resistance, respectively). S aureus and CNS were susceptible to linezolid (15.4% and 0% resistance, respectively), and vancomycin (15.5% and 11% resistance, respectively). Conclusion: This is the first study to report the emergence of vancomycin- and linezolid-resistant S aureus in Egypt. Newer generation quinolones (moxifloxacin and gatifloxacin) were more active than older quinolones (ciprofloxacin and ofloxacin) against S aureus and CNS, suggesting the use of newer generation quinolones in the prophylaxis of cancer patients. © 2007 by American Society of Clinical Oncology.