Phenotypic and Molecular Characterization of Antibiotics Resistance E. Cloacae Isolates.

The present study aimed detecting and characterizing of β-lactamases producing E.cloacae isolated from different clinical sources in Hilla hospitals using phenotypic and molecular methods. A total of 308 samples were collected from two major hospitals at Hilla Province from October 2013 to April 2014. All isolates were tested biochemically, it was found that only 15 isolates from all isolates were belonging to Enterobactercloacae. All E. cloacae isolates were primarily screened for β-lactams resistance. Antibiotic susceptibility and minimum inhibitory concentration tests were performed using disk diffusion and agar dilution methods, respectively. The molecular study documented a widespread of Amp C genes among isolates of E. cloacae isolatesrepresented by 6/15(40%) positive isolates for Amp C primers. PCR assay revealed that prevalence rate of bla-TEM gene among tested isolates was 9(60%). followed by the bla-OXA gene was detected only in 3(20%).While bla-VEB gene and bla-SHV gene was not detected in any of the isolates. Some virulence factors of bacteria were also studied, and the results showed that all bacterial strains have capsule ,the results also also detected biofilm formation among isolates and the results revealed that 13(86%) of the isolates are biofilm former.

Distribution of beta-Lactamase Genes Among Carbapenem-Resistant Klebsiella pneumoniae Strains Isolated From Patients in Turkey

BACKGROUND: The emergence of carbapenem-resistant Klebsiella pneumoniae poses a serious problem to antibiotic management. We investigated the beta-lactamases in a group of carbapenem-resistant K. pneumoniae clinical isolates from Turkey. METHODS: Thirty-seven strains of K. pneumoniae isolated from various clinical specimens were analyzed by antimicrobial susceptibility testing, PCR for the detection of beta-lactamase genes, DNA sequencing, and repetitive extragenic palindronic (REP)-PCR analysis. RESULTS: All 37 isolates were resistant to ampicillin, ampicillin/sulbactam, piperacillin, piperacillin/tazobactam, ceftazidime, cefoperazone/sulbactam, cefepime, imipenem, and meropenem. The lowest resistance rates were observed for colistin (2.7%), tigecycline (11%), and amikacin (19%). According to PCR and sequencing results, 98% (36/37) of strains carried at least one carbapenemase gene, with 32 (86%) carrying OXA-48 and 7 (19%) carrying NDM-1. No other carbapenemase genes were identified. All strains carried a CTX-M-2-like beta-lactamase, and some carried SHV- (97%), TEM- (9%), and CTX-M-1-like (62%) beta-lactamases. Sequence analysis of bla(TEM) genes identified a bla(TEM-166) with an amino acid change at position 53 (Arg53Gly) from bla(TEM-1b), the first report of a mutation in this region. REP-PCR analysis revealed that there were seven different clonal groups, and temporo-spatial links were identified within these groups. CONCLUSIONS: Combinations of beta-lactamases were found in all strains, with the most common being OXA-48, SHV, TEM, and CTX-M-type (76% of strains). We have reported, for the first time, a high prevalence of the NDM-1 (19%) carbapenemase in carbapenem-resistant K. pneumoniae from Turkey. These enzymes often co-exist with other beta-lactamases, such as TEM, SHV, and CTX-M beta-lactamases.

Epidemiologic analysis of Ampicillin Resistance in Shigella sonnei Isolates by blaTEM Hybridization

Forty-seven ampicillin-resistant R plasmids derived from 218 Shigella sonnei isolates from Daegu and Gwangju areas from 1980 to 2000 were epidemiologically compared by fragments of restriction endonuclease patterns by EcoRI and SmaI, and by Southern hybridization with a blaTEM-1 probe. All the ampicillin-resistant strains isolated in the 1980S carried a conjugative R plasmid responsible for multiple resistance other than ampicillin, and an ampicillin-resistance plasmid. Ampicillin-resistant strains isolated in the 1990S harbored single conjugative R plasmid encoding ampicillin resistance along with variable antimicrobial resistances. The restriction endonuclease digestion patterns and Southern hybridiztion analysis of conjugative R plasmids showing identical resistance pattern and a same size showed different fragment and Western blotting patterns according to different isolation years and areas, while identical patterns were observed among the plasmids derived from a same isolation year and area. These findings suggest that ampicillin resistance among S. sonnei isolates was due to introduction of ampicillin-resistant R plasmids originated from different sources.