Isolation of ESBL Producing Non-Fermentative Aerobic Bacilli from Stool Samples of Hospitalized and Non- Hospitalized Patients Download PDF

Purpose: The aim of this study was to investigate the faecal carriage rate of TEM, SHV and CTX type ESBL producing non-fermentative aerobic bacilli (NFAB). Also these ESBLs were inspected among clinical isolates of Pseudomonas aeroginosa (PA) by phenotypic and genotypic methods. Methods: Two hundred fresh stool samples collected from non-hospitalized and hospitalized patients were cultured on MacConkey agar supplemented with 2 mg/L cefotaxime. Non-fermentative bacteria were identified after 24 hr. incubation at 37°C by routine biochemical tests. One hundred clinical isolates of NFAB also were collected. Phenotypic tests were used to select ESBLs producing bacteria and susceptibility of isolates was determined by disc diffusion method. PCR was used to identify TEM, SHV and CTX type ESβLs producing isolates. Results: Six (6%), 4 (4%) and 78 (%78) bacteria from stool of inpatients, outpatients and clinical specimens were identified as cefotaxime resistance nonfermentative bacteria. All isolates of inpatients and out patients were resistant to cefotaxime, trimethoprim sulfamethoxazole, gentamicin, kanamycin and amoxicilin-clavulanic acid while Polymyxin B and Meropenem were 100% effective. Clinical isolates were mostly sensitive to amikacin, Gentamicin, cefepim and Polymyxin B. PCR analysis showed CTX-M and SHV resistance genes in %100 (2 of 2) of inpatient isolates. None of these genes was observed in outpatient isolates. Amongst clinical isolates %35.2 (12 of 34) were identified to be positive for the blaTEM gene. Conclusion: Although unlike clinical isolates, stool carriage rate of CTX, SHV and TEM type ESBL producing PA among inpatients and out patients are very low but still could be considered as a source of PA infections in hospitals.