Acinetobacter baumannii (A. baumannii) is an important opportunistic pathogen responsible for nosocomial infections worldwide at recent decades. Biofilm formation by A. baumannii leads to antibiotic resistance and survives on abiotic and biotic surfaces. In the present study we aimed to assess the ability of biofilm formation in clinical and environmental isolates of A. baumannii by phenotypic methods and to detect the presence of genes involving in the biofilm development; bap, ompA, csuE, abaI, and blaPER-1by PCR method. Totally 120 A. baumanniin isolates, 98 clinical, and 22 environmental were evaluated for biofilm formation using the modified Microtiter plate method, Congo red agar methods, and the existence of genes related to biofilm by standard PCR. The phenotypic results showed that the biofilm formation rate was 10.8% isolates that in environmental A. baumannii isolates were higher than clinical isolates. The abaI, csuE, and ompA genes were detected in all isolates with biofilm formation and the bap and blaPER-1genes were positive in 14.2% and 13.3% of A. baumannii isolates, respectively. The sequence of genes were submitted in NCBI. Based on our results, the Congo red agar method was significantly better than the Microtiter plate technique for phenotypic evaluation of biofilm formation in the A. baumannii. Our study indicates that abaI, csuE, and ompA genes were detected in all isolates unlike the bap and blaPER-1genes.
Background: Enterococci are a natural part of the genito-intestinal and gastrointestinal normal flora in humans and are widely distributed in the environment and are one of the most important causes of nosocomial infections. Objectives: The aim of this study was to identify Enterococcus spp. from vaginal samples of pregnant women and measure their antibiotic resistance patterns. Methods: This descriptive study was performed on 602 strains. Vaginal swabs were cultured for Enterococcus spp. from pregnant women at 35 -37 weeks of pregnancy in Kerman city, Iran, during April 2013 to March 2014 or in labor samples transported to the laboratory using Amies transport medium. Swabs were cultivated in Todd Hewitt broth medium and subsequently plated on blood agar plates containing gentamicin and nalidixic acid. Antimicrobial susceptibility testing was performed for enterococci by disk diffusion and minimum inhibitory concentrations (MIC). Results: Vaginal colonization of Enterococcus genus was 8.14%. Parameters of age, parity, history of abortion, history of ruptured membranes, vaginal discharge and other vaginal signs (itching and so on) had no influence on vaginal colonization of Enterococcus spp. The predominant species were respectively E. faecalis 89.8%, E. faecium 6.1% and other Enterococcus spp. 4.1%. All samples were sus-
Objective
The purpose of the present study was to investigate the antimicrobial susceptibility pattern, biofilm production, and the presence of biofilm genes among the S. maltophilia clinical isolates. A total of 85 clinical isolates of S. maltophilia were collected from patients referred to several hospitals. Susceptibility to antibiotics was investigated by disc diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). By the crystal violet staining method, the capability of biofilm formation was examined. The genes associated with biofilm production were investigated by the PCR-sequencing techniques.
Results
All isolates were resistant to doripenem, imipenem, and meropenem. Minocycline, trimethoprim/sulfamethoxazole and levofloxacin exhibited the highest susceptibility of 100%, 97.65%, and 95.29%, respectively. The results of crystal violet staining assay showed that all isolates (100%) form biofilm. Moreover, 24 (28.23%), 32 (37.65%), and 29 (34.12%) of isolates were categorized as weak, moderate, and strong biofilm producers, respectively. Biofilm genes including rpfF, spgM and rmlA had an overall prevalence of 89.41% (76/85), 100% (85/85) and 84.71% (72/85), respectively. Rational prescribing of antibiotics and implementation of infection control protocols are necessary to prevent further infection and development of antimicrobial resistance. Combination strategies based on the appropriate antibiotics along with anti-biofilm agents can also be selected to eliminate biofilm-associated infections.
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