Microbial spectrum and drug resistance profile in solid malignancies in a large tertiary hospital from Palestine
Authors: Rabayah Rama , Alsayed Ranyah B. , Taha Adham Abu , Salameh Husam , Amer Riad , Sabateen Ali , Aiesh Banan M. , Zyoud Sa’ed H. 
Published: April 2022

Abstract
Background
Since the available data for bloodstream infections in solid malignancy tumors are somewhat limited in Palestine, prevention of infection before the occurrence, controlling it when it occurs, and implementing stewardship programs are important ways in the whole therapy of solid tumor patients, which is becoming challenging recently with the evolution of more antimicrobial drug-resistant pathogens. Therefore, our study aims to assess the microbial spectrum and antimicrobial sensitivity and the overall outcome related to many clinical risk factors in patients with solid tumor patients seeking care in a referral hospital as an experience from a developing country.

Methods
From the onset of 2018 to the end of 2020, a total of 116 episodes with positive blood cultures were retrospectively studied and analyzed in 96 patients who had solid tumors in a referral hospital in Palestine.

Results
We identified 116 positive blood cultures in 96 patients with a male to female ratio of 1:1. The mean age was 58 years. Breast cancer was the tumor most frequently recorded (13.5%), followed by urinary tract tumors (10.4%). The most common source of episodes with positive blood culture was catheter-related. Gram-positive bacteria accounted for 52.6% of blood cultures with the predomination of Staphylococcus species. On the contrary, Gram-negative bacteria were documented in 39.7% of the cultures, with E. coli being the most frequent bacteria. Regarding fungi that were only Candida species, it was isolated in 15.5% of the cultures.28.4% of patients started on a single antimicrobial as an initial regimen, the remaining started combination antimicrobial therapy. The initial antimicrobials used most frequently were aminoglycosides in 29.3% of the episodes. All species of Staphylococcus were sensitive to vancomycin. Enterococcus species were fully resistant to ciprofloxacin. In the case of E. coli, the isolates were 100% sensitive to imipenem, meropenem, and amikacin and were mostly resistant to ampicillin, where the sensitivity was only about 19.5%. P.aeruginosa was sensitive in 83.3% of cultures to both piperacillin-tazobactam and gentamicin, but highly resistant to imipenem, in which sensitivity decreased to 50%. The isolates of Klebsiella species were 72.2% sensitive to gentamicin, meropenem, and imipenem and 100% resistant to ampicillin. A. baumannii was 50% sensitive to trimethoprim-sulfamethoxazole. Candida species showed high sensitivity to both caspofungin and flucytosine (83.3%), followed by 77.8% sensitivity to voriconazole. Death was reported in 27.6% of the episodes and there was a significant relationship between shock at presentation and death (p = 0.010).

Conclusions
The findings of this investigation confirm the prevalent BSI seen in patients with solid malignancies and demonstrate a significant percentage of antibiotic resistance. Therefore, stewardship programs that dig deep before using any type of antimicrobials will help reduce the risk of resistance to antibiotics. In addition, the implementation of infection control surveillance plays an important role in decreasing the risk of contamination.