Virulence Genes and Antibiotic Susceptibilities of Uropathogenic E. coli Strains.

BACKGROUND: The aim of this study is to detect the presence of and possible relation between virulence genes and antibiotic resistance in E. coli strains isolated from patients with acute, uncomplicated urinary tract infections (UTI). METHODS: 62 E. coli strains isolated from patients with acute, uncomplicated urinary tract infections (50 strains isolated from acute uncomplicated cystitis cases (AUC); 12 strains from acute uncomplicated pyelonephritis cases (AUP)) were screened for virulence genes [pap (pyelonephritis-associated pili), sfa/foc (S and F1C fimbriae), afa (afimbrial adhesins), hly (hemolysin), cnf1 (cytotoxic necrotizing factor), aer (aerobactin), PAI (pathogenicity island marker), iroN (catecholate siderophore receptor), ompT (outer membrane protein T), usp (uropathogenic specific protein)] by PCR and for antimicrobial resistance by disk diffusion method according to CLSI criteria. RESULTS: It was found that 56 strains (90.3%) carried at least one virulence gene. The most common virulence genes were ompT (79%), aer (51.6%), PAI (51.6%) and usp (56.5%). 60% of the strains were resistant to at least one antibiotic. The highest resistance rates were against ampicillin (79%) and co-trimoxazole (41.9%). Fifty percent of the E. coli strains (31 strains) were found to be multiple resistant. Eight (12.9%) out of 62 strains were found to be ESBL positive. Statistically significant relationships were found between the absence of usp and AMP - SXT resistance, iroN and OFX - CIP resistance, PAI and SXT resistance, cnf1 and AMP resistance, and a significant relationship was also found between the presence of the afa and OFX resistance. CONCLUSIONS: No difference between E. coli strains isolated from two different clinical presentations was found in terms of virulence genes and antibiotic susceptibility.

EHEC, EPEC, and ETEC strains and their antibiotic resistance in drinking and tap water samples.

BACKGROUND: Investigating of the presence of Enterohemorrhagic E. coli (EHEC), Enterotoxigenic E. coli (ETEC), Enteropathogenic E. coli (EPEC) strains and their antibiotic resistance in natural spring waters and tap waters from two university hospitals, in Istanbul. METHODS: E. coli strains isolated from water samples were identified by polymerase chain reaction (PCR) method using stx-1, stx-2, eaeA genes specific for EHEC; eaeA, bfp genes specific for EPEC and lt, st genes specific for ETEC. Antibiotic susceptibility tests were done according to the Kirby-Bauer method using The Clinical and Laboratory Standards Institute (CLSI) criteria. RESULTS: E. coli strains were isolated from only five (2.7%) out of 184 water samples. Only one of the 36 E. coli strains isolated from these five water samples was found to be extended spectrum beta lactamase (ESBL) positive. According to PCR, ten E. coli strains isolated from one drinking water were identified as ETEC. Other than E. coli strains, coliforms and non-fermentative Gram negative bacteria were also isolated from waters. It was shown that 60 (81.1%) of these 74 strains isolated, other than E. coli, were found to be multiple resistant. CONCLUSIONS: Contrary to our expectations, it has been shown that natural spring waters (drinking waters) can be much more contaminated with fecal bacteria when compared with tap waters. The presence of pathogenic E. coli strains and antibiotic resistant Gram negative bacteria especially in drinking waters emphasize the importance of these types of studies.

[In vitro susceptibility of Enterococcus strains to high level aminoglycosides and heavy metals]. / Enterokok suslarinin yüksek düzeyde aminoglikozidlere ve agir metallere karsi in vitro duyarliliklarinin arastirilmasi.

The widespread use of antimicrobial agents in the hospitals and environmental contamination with heavy metals are increasingly related to resistance progression in microorganisms. The aim of this study was to investigate the resistance of enterococci to high level aminoglycosides and some heavy metals [lead (Pb+2), cadmium (Cd+2), mercury (Hg+2), arsenic (As+5)]. A total of 39 Enterococcus strains, isolated from stool and rectal swabs of hospitalized patients were included to the study. Twenty of the strains were resistant to glycopeptides (11 were resistant to vancomycin + teicoplanin and 9 were resistant to only vancomycin). Disk diffusion method was performed to determine the high level resistance to aminoglycosides (gentamicin 120 microg and streptomycin 300 microg), and agar dilution method was used to detect the sensitivities of the strains against different concentrations (0.005-20 mM) of heavy metals. Since there is no specified minimum inhibitory concentration (MIC) breakpoints for heavy metals, resistance criteria described in previous studies were used. Accordingly, enterococci which exhibited MIC > or = 1 mM for lead and cadmium, MIC > or = 0.1 mM for mercury, and MIC > or = 10 mM for arsenic were accepted as resistant. High level aminoglycoside (HLAG) resistance rates were found as 91% (10/11) for vancomycin (V) + teicoplanin (T) resistant and 42% (8/19) for glycopeptide susceptible strains. While all of the isolates were resistant to lead (100%), arsenic (2.6%) and mercury (2.6%) resistance was detected in one isolate for each metal. No cadmium resistance has been detected. In our study, enterococci have exhibited seven different resistance profiles (10 strains were resistant to V + T + HLAG + Pb; 1 was resistant to V + T + Pb; 1 was resistant to V + As + Pb; 1 was resistant to HLAG + Hg + Pb; 8 were resistant to V + Pb; 7 were resistant to HLAG + Pb; 11 were only resistant to Pb). Resistance to antibiotics (aminoglycosides and/or vancomycin and/or teicoplanin) and heavy metals (lead and arsenic and/or mercury) were detected concurrently in 28 (%71.8) of the strains. It was considered remarkable that all of the isolates were resistant to lead and there was no difference between antibiotic-resistant and-susceptible strains in terms of lead resistance. In conclusion, further investigations are needed to reveal the extreme lead resistance and the relations between antibiotic and heavy metal resistances in clinical enterococcus strains.