Frequency of Pseudomonas aeruginosa, its antibiotic susceptibility pattern and biofilm formation in fecal specimens of patients with inflammatory bowel disease and colorectal cancer compared to healthy ones

BACKGROUND AND ABJECTIVEThe intestinal carriage of Pseudomonas aeruginosa is likely a consequence of the opportunistic nature of this species. It is a common colonizer of the human intestine upon hospitalization and antibiotic treatment. P. aeruginosa may induce epithelial cell apoptosis, inflammation and cancer-related epithelial phenotypes in genetically predisposed hosts. The aim of this study was to determine P . aeruginosa fecal carriage rate in healthy individuals and in patients with inflammatory bowel disease (IBD) and colorectal cancer (CRC) and to detect the ability of biofilm formation and antibiotic susceptibility patterns in these isolates.MATERIALS AND METHODSA total of ۷۴ stool samples from confirmed IBD(n=۴۸) and CRC(n=۲۶) patients and ۷۴ stool samples from healthy volunteers admitted to Kerman University affiliated hospitals were collected .CRC patients had not received any chemotherapy or radiation therapy and none of the participants had not antibiotic treatment in the last month. P. aeruginosa isolates were identified by conventional biochemical tests. Microtiter plate assay was performed for assessment of biofilm production. Disk diffusion and the microdilution broth methods were employed to determine the antibiotic susceptibility pattern of isolates.RESULTS AND DISCUSSIONCarriage rate with P. aeruginosa was ۱۶.۲%, ۱۲.۵% and ۱۵.۳۸% in healthy individuals, IBD and CRC patients, respectively. The ability of strong biofilm formation was seen in all isolates from CRC patients while it was ۶۶.۶% in isolates from IBD patients and healthy people. However, there were no significant differences between these groups. All isolates were susceptible to ceftazidime, cefepime and colistin and more than ۹۰% of isolates were susceptible to piperacillin tazobactam. Antibiotic susceptibility pattern was different between isolates from two groups: the highest rates of non-susceptibility were found against levofloxacin (۸۳.۳%), piperacillin (۷۵%), and meropenem and aztreonam (each of ۶۶.۶%) in isolates from healthy subjects while in isolates from patients, the most prevalent non-susceptibility was found against meropenem (۶۶.۶%), amikacin and gentamicin (each of ۵۸.۳%). Only one isolate from healthy group, showed multidrug resistance .CONCLUSIONAs the titter, distribution and even virulence of P. aeruginosa strains may be dynamic in intestinal environment, repeatedly assessment should be designed to clarify the role of these strains in development of gastrointestinal diseases.

کلیدواژه ها:

Pseudomonas aeruginosa ، inflammatory bowel disease ، colorectal cancer ، stool