Comparison of TechLab Clostridium difficile Tox-A enzyme immunoassay and Bartels Prima system toxin-A EIA.

We evaluated the Bartles Clostridium difficile toxin A test and the TechLab Tox-A test to detect C. difficile toxin A in stool. The results were compared with C. difficile cytotoxicity assays. Of the 463 specimens tested 82 (17.7%) tested positive by cytotoxicity assay. The sensitivity, specificity, and positive and negative predictive values of the TechLab EIA were 86.6%, 93.7%, 74.7%, and 97.0%, respectively. For the Bartels Prima EIA, sensitivity, specificity, and positive and negative predictive values were 95.1%, 95.5%, 82.1%, and 98.9%, respectively. The differences in sensitivity were statistically significant. Indeterminate results requiring repeat testing were more common with the TechLab EIA than with the Bartels Prima EIA. Of the two kits, the Bartels EIA is preferable, primarily because of its increased sensitivity.

A comparison of the API Uriscreen with the Vitek Urine Identification-3 and the leukocyte esterase or nitrite strip as a screening test for bacteriuria.

The API Uriscreen is a rapid urine-screening test based on the detection of catalase activity present in somatic cells and in many of the bacteria commonly causing urinary tract infections. Of 487 routine, outpatient urine specimens processed by conventional quantitative culture, API Uriscreen, Vitek UID-3 panel, and a leukocyte esterase-nitrite strip, 142 had no growth. Of 336 urine specimens with > or = 10(3) colony-forming units (CFU)/ml, 79 were considered to be indicative of possible or probable urinary tract infection (Cumitech 2A). The sensitivity and specificity of the API Uriscreen for the detection of bacteriuria at > or = 10(5) CFU/ml were 62% and 85%, those of the leukocyte esterase-nitrite strip was 61% and 82%, those of the Vitek UID-3 panel were 91% and 66%. When bacteriurias were classified into possibly or probably indicative of urinary tract infection, the sensitivity and specificity of the API Uriscreen at > or = 10(5) CFU/ml were 87% and 78%, those of the leukocyte esterase-nitrite were 84% and 76%, those of the Vitek UID-3 were 93% and 55%. In this study, we consider the API Uriscreen did not have significant advantages over the leukocyte esterase-nitrite strip.

Survey of Bacteroides fragilis group susceptibility patterns in Canada.

The in vitro activities of penicillin, clindamycin, chloramphenicol, metronidazole, piperacillin, piperacillin-tazobactam, ticarcillin, ticarcillin-clavulanate, ampicillin-sulbactam, cefoxitin, ceftizoxime, cefotetan, moxalactam, and imipenem against 348 Bacteroides fragilis group isolates collected from six Canadian cities during 1990 were determined by the National Committee for Clinical Laboratory Standards (NCCLS) agar dilution technique. All isolates were susceptible to chloramphenicol, metronidazole, piperacillin-tazobactam, and imipenem. For the other antibiotics tested, the following resistance rates were observed: penicillin, 97%; clindamycin, 9%; piperacillin, 19%; ticarcillin, 31%; ticarcillin-clavulanate, 0.28%; ampicillin-sulbactam, 0.85%; cefoxitin, 26%; ceftizoxime, 15%; cefotetan, 53%; and moxalactam, 17%. Susceptibility profiles to beta-lactam antibiotics varied among the different species tested: B. fragilis and Bacteroides vulgatus demonstrated lower resistance rates than Bacteroides distasonis and indole-positive Bacteroides thetaiotaomicron and Bacteroides ovatus. Ceftizoxime results should be interpreted cautiously, because the MICs obtained with the recommended NCCLS control strain were lower than expected.

Pathogenic marine vibrio species in selected Nova Scotian recreational coastal waters.

Seven heavily frequented coastal recreation sites serving Metropolitan Halifax and Dartmouth were investigated to determine the numbers and species of pathogenic marine vibrios (PMV) present. Seawater, mussels and sea gull feces were cultured using quantitative methods and the effects of temperature and fecal pollution noted. Emergency rooms serving the sites under surveillance were monitored for PMV-related infections. All 11 recognized species of pathogenic marine vibrios were recovered from the 7 sites. Estuarine sites yielded a greater variety of species and greater numbers of PMV than non-estuarine sites. Culture of hand washings after immersion in seawater did not demonstrate contamination of skin by PMV. We did not demonstrate any cases of PMV infection associated with the 7 surveillance sites. PMV contamination of marine recreational waters does not frequently result in superficial infections.

Rapid identification of Candida albicans using 4-methylumbelliferyl N-acetyl-beta-galactosaminide.

Rapid identification of Candida albicans is performed mainly by the germ-tube test. However, recent reports have suggested that up to 5% of C. albicans species can give false negative results. We describe the use of 4-Methylumbelliferyl N-acetyl-beta-D-galactosaminide (4-MAG) conjugate as an alternative to the germ-tube test. Our results indicate that, in comparison to the germ-tube test, the 4-MAG test has a sensitivity of 100% and a specificity of 92%. Candida tropicalis can give false-positive results, and that a further screening test is required to identify this species. Problems reading end-points were not encountered.

Correlation of antibiotic usage with an antibiotic policy in a urological ward.

An antibiotic policy for a urological ward was largely implemented by restrictive antibiotic sensitivity reporting, and indications for prophylaxis were derived from the feature of 40 episodes of bacteraemia associated with urological procedure. Of 510 patients admitted to this ward, 30-8 per cent received antibiotics. Of 187 antibiotic courses, 53 per cent were for treatment and 43 per cent for prophylaxis. The stated indications were considered dubious in 28 per cent of courses of treatment and irrational in 13 per cent of courses of prophylaxis. Of 1368 days of antibiotic use, co-trimoxazole and amoxycillin/ampicillin accounted for 84.6 per cent, and gentamicin for 5.6 per cent. The modal duration of courses of co-trimoxazole, amoxycillin/ampicillin, and gentamicin were 5, 5 and 1 days respectively. Antibiotics whose sensitivities were not reported were rarely used, and there was no prescription of cephradine, cefoxitin, cefuroxime or amikacin. In general, antibiotic administration corresponded well with policy guidelines.

Gentamicin-resistant Klebsiella aerogenes in a urological ward.

A gentamicin-resistant strain of Klebsiella aerogenes was isolated from the urine of 17 patients out of 237 admitted to a male urological ward between Jan. 21 and May 9, 1977. The factors most frequently associated with K. aerogenes in the urine were catheterisation and antibiotic therapy. Often the epidemic strain (type K16) was found not only in the patients' faeces but also on more remote skin sites such as hands, knees, groins, and the umbilicus. Resistance to gentamicin and many other antibiotics was R-factor mediated. Barrier nursing of colonised patients, stringent staff handwashing with chlorhexidine, and the use of disposable aprons seemed to contain the outbreak. Hand carriage was demonstrated in one nurse 62 days after she had left the ward.