Bacteremia in Cancer Patients: A Two Center Experience of Isolates and Spectrum of Antibiotic Resistance Pattern

Abstract

Background: Bacteremia is a frequent condition in cancer patients with a significant morbidity and mortality worldwide, which is a medical crisis that needs broad-spectrum antibiotic treatment. Objectives: This study examined bacteremia in cancer patients from two medical centers regarding isolates and spectrum of antibiotic resistance pattern. Patients and Methods: This was a prospective experimental investigation performed in Tehran and Karaj Cities, Iran. From the blood culture bottles, isolation and identification of the bacteria were performed by conventional microbiological techniques. In vitro antibiotic resistance pattern of the isolates was determined by CLSI guidelines. Genomic DNA was isolated by DNA extraction kit. Each gene was separated by agar gel electrophoresis. Results: In total, 68 blood culture bottles were received from cancer patients, from which 12 (17.65%) samples had positive results. The most common bacterial pathogen isolated was E. coli, accounting for 5 (33.33%). While each of S. aureus, B. cereus and K. pneumonia accounted for 3 (20%) samples. Penicillin, ampicillin, gentamicin, cefoxitin, trimethoprim sulfamethoxazole and tetracycline were the most resistant antibiotics with 100% resistance to the tested E. coli isolates. Similarly, S. aureus was 100% resistant to gentamicin and sulfamethoxazole. Identification of the 88 bp phoA gene in E. coli isolates was 100%. Similarly, the 310 bp mecA fragment was obtained from all of the resistant S. aureus isolates after DNA amplification. Conclusions: All the bacterial isolates were associated with a high resistance to various antibiotics and this resistant pattern could be confirmed by detection of a particular gene for each bacterium.