Browsing by Subject "Nitrites"

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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 of gastric aspirate nitrite, pH, bacterial flora and mutagenicity in man
    (1987) Coldrey, Norman A; Forder, A A; Dent, David Marshall
    Gastric aspirate specimens were collected from patients w~th clinically diagnosed gastric carcinoma and from non-carcinoma patients. The nitrite concentration and pH values of the aspirates were measured, the microorganisms present in selected specimens were isolated and identified, and the mutagenicity ratios of the aspirates were determined. The median nitrite concentration of the gastric aspirates from the carcinoma patients was significantly higher than that obtained for the non-carcinoma patients. A positive correlation was found between the nitrite concentration and the pH values of all the specimens tested, and a marked increase in nitrite levels at pH values above 6,0 was evident in specimens from the coloured ethnic "normal" subgroup. Gastric aspirate nitrite concentrations did not correlate with salivary values. The presence of microorganisms in gastric aspirates was shown to be pH dependent. Gastric aspirates with a pH < 2,0 were sterile, below pH 4,0 only acidophilic bacteria survived, whereas above pH 4,0, numerous species, predominantly members of the oral microflora, were isolated. The mean mutagenicity ratio of the gastric aspirates from the carcinoma patients was found to be significantly higher than that found for the control group. There was a positive correlation between the mutagenicity ratios of all the gastric specimens and pH with a maximum at a pH value of approximately 6,0.