سارا فتحی زاده

Enterococci are among the normal microbial flora in human and animals digestive tract. The nosocomial pathogenicity of enterococci has emerged in recent years and has caused great concern due to developing resistance to many antimicrobial agents. The aim of this study was to investigate and identify the prevalence of VRE (vancomycin resistant enterococcus) within Enterococci isolates obtained from different parts of the hospital. Putative Enterococci (n=120) were isolated on Membrane Filter Enterococcus Selective Agar Medium and supplemented with 2, 4 and 8 µgr/ml vancomycin in medical samples. A total isolates passed the standard biochemistry tests for the genus and species as well as their specific primers. The antibiotic susceptibility was determined by the disc diffusion method for 8 antibiotics. Microbiologically-influenced corrosion (MIC) of vancomycin was also done using Agar-dilution assay by CLSI recommendations. Results showed that 38 and 84 of the isolates were E. faecium and E.faecalis, respectively. According to antimicrobial susceptibility tests 45, 88, 103, 42, 83, 73, 54 and 95 of the isolates were resistant to vancomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, penicillin, ampicillin and erythromycin, respectively. MIC test on 70% of the isolates was>256 µgr/ml. Despite the fact that the prevalence of VRE strains belongs to two species, E. faecium had high resistance to a broad range of antibiotics. The results of this study indicate the important role of medical samples as reservoirs of resistance elements. Early detection of VRE with their virulence trait will help in preventing the spread of vancomycin resistant enterococcus species and urgent infection control is required in hospital setting

Wound infection is a predominant cause of death in burned patients who are clearly at increased risk of nosocomial infections. Pseudomonas aeruginosa is the most common cause of burn infections and is difficult to treat because of having high level of resistance to antibiotics. The aim of this study was to perform isolation, identification and determination of antibiotics resistance pattern of P. aeruginosa strains isolated from wounds of hospitalized burn patient. Biochemical and molecular tests were used for identification of the P. aeruginosa and antibacterial susceptibility test was performed using disk diffusion (Kirby- Bauer) methods. Then, the minimum inhibitory concentration (MIC) was performed for four representatives of different groups of antibiotics. Among 94 evaluated strains of P. aeruginosa, 83 isolates (88.3%) were multi drugs resistant. Based on Kirby-Bauer method, the most resistance was seen to cefepime (89.5 %) and among the antibiotics studied to determine the MIC, the most resistance was observed to ciprofloxacin (89 %). These results indicate high range of resistance to different antibiotics among strains of P. aeruginosa isolated from burn wounds of patients. So, the fast and accurate measurement and evaluation of antibiotic resistance for appropriate antibiotic therapy of burned patients is imperative.