Evaluation of antibiotics resistance including fosfomycin in Pseudomonas aeruginosa isolates from cystic fibrosis patients in Palestinian Hospital over 5 years
Bayan Asad “Mohammad Rajab” Subb Laban
بيان أسعد محمد رجب صب لبن
Background: Antipseudomonal agents, like other antibiotics, will develop a resistance when taken continuously for many years. In diseases like cystic fibrosis (CF),the most dangerous pathogen colonizing the lungs is Pseudomonas aeruginosa and antibiotic resistance has a high chance to occur. In Palestine, there is no accurate data about resistance in these bacteria among CF patients. The increased prevalence of multi-drug resistant strains, allergic reactions, nephrotoxicity and other side effects of antibiotic used among patients with CF limits the number of antibiotics available to treat pulmonary exacerbations. Fosfomycin, a unique broad spectrum bactericidal antibiotic, might offer an alternative therapeutic option in such cases. Objectives: The aim of this study was to determine the level and change in the rates of resistance over the years for mostly commonly used antibiotics in Pseudomonal infection in CF patients. In addition, the study evaluated the effect of fosfomycin on this bacteria. Methods: To study antibiotics resistance tested in sputum samples over the past 5 years, a retrospective study was carried out in the Department of Microbiology at Caritas Baby Hospital. Clinical and microbiological data were extracted from medical database for pediatric CF patients. The results were analyzed using Microsoft Excel Software 2010 and Statistical Package for Social Sciences (SPSS) program version 20. In addition, 129Pseudomonas aeruginosa sputum samples from CF patients were tested for fosfomycin sensitivity by using two different methods minimum inhibitor concentration (MIC) and disc diffusion(DD). Results: The sensitivity to commonly used antibiotics in treatment P.aeruginosa infection in CF pediatric patients in Palestine was92.3%, 91.9%, 89.1%, 87.7%, 76.5% and 73.5% for ciprofloxacin, ceftazidime, piperacillin-tazobactam, meropenem, amikacin and gentamicin; respectively. Over the past 5 years, the sensitivity was oscillating slightly with no deterioration in sensitivity toward these antibiotics. The vast majority of patients are from the south of the west bank (70.1%), and also the resistance in this area is higher for all antibiotics. Males are slightly more sensitive than females. Regarding ages, as the age increased, resistance to antibiotics increased. In vitro, due to the lack of susceptibility breakpoint of fosfomycin for P.aeruginosa in CLSI and EUCAST, sensitivity to fosfomycin according to MIC results was determined based on the existing CLSI breakpoints for the Enterobacteriaceae; ≤64 is sensitive. MIC method showed good activity for fosfomycin toward P.aeruginosa isolates from CF patients; nearly 40% sensitive, the most sensitivity was in mucoid type (57.5%). DD method showed a strong correlation with MIC method, Pearson Correlation between MIC and DD 200 μg was -0.889, between MIC and DD 50 μg was -0.768, and also 0.932 between DD 200μg and DD 50μg. Conclusions: In Palestine, the sensitivity to commonly used antibiotics in treatment P.aeruginosa infection in CF pediatric patients was stable, and there was no deterioration in sensitivity toward these antibiotics over the past 5 years. Fosfomycin showed a good sensitivity towards Palestinian P.aeruginosa isolates in CF patients, so it can be considered as a choice in the antibiotics used in treating P.aeruginosa infection (particularly the mucoid type) in CF patients in the future, but it still needs more research. Keywords: Cystic Fibrosis, Pseudomonas Aeruginosa , Fosfomycin, Bacterial Resistance.