Browsing by Subject "Escherichia coli"

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    Open Access
    Antimicrobial susceptibility of organisms causing community-acquired urinary tract infections in Gauteng Province, South Africa
    (2013) Lewis, David A; Gumede, Lindy Y E; Van der Hoven, Louis A; De Gita, Gloria N; De Kock, Elsabe J E; De Lange, Telsa; Maseko, Venessa; Kekana, Valentia; Smuts, Francois P; Perovic, Olga
    BACKGROUND: Patients with community-acquired urinary tract infections (UTIs) frequently present to healthcare facilities in South Africa (SA). AIM: To provide information on UTI aetiology and antimicrobial susceptibility of pathogens. METHODS: We recruited women with UTI-related symptoms, who tested positive for ≥2 urine dipstick criteria (proteinuria, blood, leucocytes or nitrites) at 1 public and 5 private primary healthcare facilities in 2011. Demographic and clinical data were recorded and mid-stream urine (MSU) specimens were cultured. UTI pathogens were Gram-stained and identified to species level. Etest-based antimicrobial susceptibility testing was performed for amoxicillin/clavulanic acid, cefixime, cefuroxime, ciprofloxacin, fosfomycin, levofloxacin, nitrofurantoin, norfloxacin and trimethoprim/sulphamethoxazole. RESULTS: Of the 460 women recruited, 425 MSU samples were processed and 204 UTI pathogens were identified in 201 samples. Most pathogens were Gram-negative bacilli (GNB) (182; 89.2%) and 22 (10.8%) were Gram-positive cocci (GPC). Escherichia coli was the most frequent GNB (160; 79.6%), while Enterococcus faecalis was the predominant GPC (8; 4.0%). The UTI pathogens had similar susceptibility profiles for fosfomycin (95.5%; 95% confidence interval (CI) 92.6 - 98.4), the 3 fluoroquinolones (94.1%; 95% CI 90.8 - 97.4), nitrofurantoin (91.7%; 95% CI 87.8 - 95.6), cefuroxime (90.1%; 95% CI 86.0 - 94.3) and cefixime (88.2%; 95% CI 83.7 - 92.6). UTI pathogens were less susceptible to amoxicillin/clavulanic acid (82.8%; 95% CI 77.5 - 88.0) when compared with fluoroquinolones and fosfomycin. Trimethoprim/ sulphamethoxazole was the least efficacious antimicrobial agent (44.3% susceptible; 95% CI 37.4 - 51.2). CONCLUSION: This study provides relevant data for the empirical treatment of community-acquired UTIs in SA.
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    Open Access
    Studies on the Vibrio alginolyticus sucrose utilization system cloned into Escherichia coli
    (1989) Scholle, Renate Regina; Woods, David R
    This dissertation forms part of the study on the molecular biology of the aerobic, collagenolytic, halotolerant, gram-negative organism Vibrio alginolyticus. The cloning, expression and regulation of the v. alginolyticus sucrose utilization system in Escherichia coli is discussed and the results of a molecular analysis of the sucrase gene (scrA) are presented. The clone pVSlOO, containing a sucrose utilization system, was isolated from a genomic library of v. alginolyticus. Plasmid pVSlOO was mapped and the origin of its insert determined by Southern blotting and DNA hybridization. The number and sizes of the polypeptide products encoded by plasmid pVSlOO were determined by DNAdirected cell-free protein synthesis. The capsule, produced by transformed and untransformed E. coli JA221 cells, was shown to be independent of the presence of plasmid pVSlOO. The sucrase activity assay was optimized with respect to time, pH, temperature and salt requirements.