Quinolone-resistant Escherichia Coli Research Articles

Diversity of Individual Dynamic Patterns of Emergence of Resistance to Quinolones in Escherichia coli From the Fecal Flora of Healthy Volunteers Exposed to Ciprofloxacin

Emergence of quinolone-resistant Escherichia coli (QREC) is an increasing clinical challenge mostly originating in fecal microbiota. The dynamics of the emergence of QREC in feces from individuals exposed to ciprofloxacin is unknown. A total of 48 healthy volunteers received oral ciprofloxacin for 14 days. Fecal specimens were collected on days 0, 8, 14, and 42. Subpopulations of QREC were detected on selective agar, genetically characterized, and compared with quinolone-susceptible E. coli (QSEC) strains collected on different days. On day 42, 34 subjects carried QSEC, and 14 carried QREC. Of the 14 who carried QREC, 9 carried quinolone-susceptible E. coli on day 0, 1 carried E. coli with a lower level of quinolone resistance on day 0, and 4 carried E. coli with similar levels of resistance and RAPD-genotypes on days 0 and 42. No plasmid acquisition and no selection of resistant mutants from the initial microbiota was evidenced in any case. In QREC emerging under ciprofloxacin pressure in the fecal microbiota, no proof of selection of quinolone-resistant mutants from the initial microbiota was evidenced, suggesting that QREC strains on day 42 were either present at undetectable levels in the initial microbiota or that exogenous acquisition of QREC strains occurred. Clinical Trials Registration. NCT00190151.

Prevalence and Risk Factors for Selection of Quinolone-Resistant Escherichia coli Strains in Fecal Flora of Patients Receiving Quinolone Therapy

Patients taking quinolones as inpatients (n = 55) or outpatients (n = 40) and newly hospitalized patients who were not on quinolone therapy (n = 41) were assessed for fecal carriage of quinolone-resistant Escherichia coli (QREC) strains before and after therapy/hospitalization. Fluoroquinolone use in the previous 6 months was found to be a risk factor for QREC carriage before therapy/hospitalization. The prevalence of QREC strains in fecal flora increased steadily with the duration of quinolone therapy.

Risk Factors for Community-Acquired Urinary Tract Infection Due to Quinolone-Resistant E. coli

Resistance to fluoroquinolone drugs is emerging among E. coli causing community acquired urinary tract infections (COMA-UTI). To evaluate demographic and clinical risk factors associated with COMA-UTI due to quinolone-resistant E. coli (QREc). In this case-control study, clinical and demographic data from 300 COMA-UTI due to E. coli (including 150 QREc) were analyzed. By univariate analysis QREc was associated to males, older patients, nursing home residents, functionally dependent, dementia, diabetes, cardiovascular diseases, immunosupression, nephrolithiasis, recurrent UTI, invasive procedures, hospitalization, and antibiotic use within previous 6 months. By multivariate analysis, use of ciprofloxacin (OR 20.6 [CI 2.3-179.2], p=0.006) or ofloxacin (OR 7.5 [CI 2.9-19.4], p<0.0001), previous invasive procedure (OR 6.6 [CI 3.0-14.7], p<0.0001), recurrent UTI (OR 4.7 [CI 2.3-9.3], p<0.0001), and previous hospitalization (OR 2.9 [CI 1.4-6], p=0.003) were identified as independent risk factors for COMA-UTI due to QREc. In patients with one or more of the risk factors identified here, the empiric use of quinolones should be reconsidered.

Antibiotics Susceptibility Pattern of Escherichia coli Strains Isolated from Chickens with Colisepticemia in Tabriz Province, Iran

Antimicrobial agents are used extremely in order to reducing the enormous losses caused by Escherichia coli infections (colibacillosis) in Iran poultry industry. In this investigation fifty avian pathogenic Escherichia coli (APEC) strains isolated from broiler chickens with colisepticemia and examined for susceptibility to antimicrobials of veterinary and human significance. In vitro antibiotic activities of 32 antibiotic substances against the isolates were determined by disc diffusion test (Kirby Bauer method). Multiple resistances to antibiotics were observed in all the isolates. The highest rate of resistance was against Nalidixic acid (100%), Lincomycin (100%), Erythromycin (97%), Oxytetracycline (95%), Chlortetracycline (95%), Tetracycline (94%), Flumequine (94%), Tiamulin (91%), Doxycycline (88%), Difloxacin (83%), Neomycin (81%), Streptomycin (81%), Trimethoprim-Sulphamethoxazole (80%), Kanamycin (77%), Enrofloxacin (76%), Norfloxacin (68%), Ciprofloxacin (67%), Chloramphenicol (67%), Furazolidone (66%), Nitrofurantoin (56%), Amoxicillin (53%) and Ampicillin (47%). Resistance to Gentamicin wasn’t observed and to Amikacin, Cefazolin, Colistin, Tobramycin, Ceftizoxime, Cefixime, Lincospectin, Ceftazidime and also Florfenicol were low. This study showed resistance rate against the antibiotics that are commonly used in poultry is very high but against them that are only used in human or less frequently used in poultry is significantly low. These findings confirm significant increase in the incidence of antimicrobial resistance in the E. coli strains is most probably due to increased use of antibiotics as feed additives for growth promotion and prevention of diseases, use of inappropriate antibiotics for treatment of diseases, resistance transfer among different bacteria and possible cross resistance between antibiotics used in poultry. This study also showed that the prevalence of Quinolone-Resistant Escherichia coli (QREC) is very high in broiler farms in Tabriz province. The high presence of QREC from broiler chickens probably is due to overuse of enrofloxacin in these farms for therapeutic purposes. The present study suggests introduction of surveillance programs to monitor antimicrobial resistance in pathogenic bacteria is strongly needed because other than animal health problems, transmission of resistant clones and resistance plasmids of E. coli from food animals (especially poultry) to humans can occur.

Risk factors for fecal quinolone-resistant Escherichia coli in Mexican children.

We determined the prevalence of, and risk factors for, fecal quinolone-resistant Escherichia coli (QREC) in 324 children from Yucatan, Mexico. QREC was higher in children with recent Salmonella infection (100%) than in children with diarrhea (61%) or healthy children (54%) (P = 0.007). Multivariate analysis identified recent hospitalization of a family member (P = 0.011, odds ratio [OR] = 5.1) and carriage of Salmonella (P = 0.004, OR = 3.7) as independent risk factors for QREC.

Clinical and molecular epidemiology of quinolone-resistant Escherichia coli isolated from urinary tract infection.

Since the use of fluoroquinolone antibiotic in clinical practice was introduced about a decade ago, quinolone-resistant E. coli (QREC) strains are being isolated with increasing frequency. From 1996 to 2000, 297 cases of urinary tract infection (UTI) due to QREC were observed in our hospital; 218 episodes (73.5%) were community acquired. The incidence of QREC UTIs increased steadily from 14.4% to 21.3% during 5 years when we compared the clinical characteristics of 60 QREC UTI with those of 80 quinolone-susceptible E. coli UTIs. Significant differences in susceptibility to various antibiotics were observed between the QREC and QSEC strains of E. coli. The multidrug resistance rate of QREC was much higher (38.3%) than those of quinolone susceptible isolates (18.8%). Prior fluoroquinolone use (p = 0.05), old age (p = 0.001), and a vegetative state (p = 0.03) were the independent risk factors for the acquisition of QREC UTI. The outcome of E. coli UTI is dependent on quinolone resistance. Thirty-day mortality was higher in QREC UTI patients, probably due to aggravation of underlying illness, but not quinolone resistance. On the basis of PFGE analysis, although some clustering was found in the hospital, genomic diversity was found among both the community and nosocomial strains. The increased frequency of QREC UTIs is thus not due to transmission of resistant strains but probably results from the selection of resistant strains from the endogenous flora of patients.

Bacteremia due to quinolone-resistant Escherichia coli in a teaching hospital in South Korea.

Quinolone-resistant Escherichia coli (QREC) strains are being isolated with increasing frequency. From 1993 to 1998, 40 cases of QREC bacteremia were observed in a teaching hospital; 25 episodes (63.5%) were community-acquired. The incidence of QREC bacteremia increased steadily, from 6.7% to 24.6% during 5 years, and correlated with the significantly increased use of fluoroquinolones (P = .003, r = 0.98). When the 40 QREC bacteremic patients were compared with 80 patients with bacteremia due to quinolone-susceptible E. coli, prior fluoroquinolone use was the only independent risk factor for QREC bacteremia (P = .001). A high APACHE II score was the only independent risk factor for death. The rate of multidrug resistance of QREC was much higher (60%) than that of quinolone-susceptible isolates (13.8%). Pulsed-field gel electrophoresis patterns of these isolates were diverse. Therefore, the isolates revealed little evidence of clonal spread and may have emerged in direct response to the selective pressure exerted by prior fluoroquinolone use.