Increasing incidence of non-O157 Shiga toxin-producing Escherichia coli (STEC) in Michigan and association with clinical illness.

Infection with Shiga toxin-producing Escherichia coli (STEC) by serotypes other than O157 (non-O157) have been increasingly reported in the United States. This increase in reporting is primarily due to the improvements in diagnostic tests. We analysed 1497 STEC cases reported in Michigan from 2001 to 2012. A significant increase in the number of non-O157 STEC cases was observed over time, and similar incidence rates were observed for O157 and non-O157 STEC cases in certain time periods. The odds of hospitalization was two times higher in O157 STEC cases relative to non-O157 STEC cases when adjusted for age and gender, suggesting that O157 STEC causes more severe clinical outcomes in all age groups. The use of population-based surveillance to better define trends and associations with disease severity are critical to enhance our understanding of STEC infections and improve upon current prevention and control efforts.

In vitro activity of sparfloxacin (AT-4140 and CI-978), a new quinolone antimicrobial agent, against Haemophilus and gram-positive cocci.

Sparfloxacin (AT-4140 and CI-978) was evaluated for activity against 194 clinical isolates of staphylococci, streptococci, Enterococcus faecalis, anaerobic Gram-positive cocci, and Haemophilus sp. The MIC of sparfloxacin for greater than 93% of the strains tested was less than or equal to 0.5 microgram/ml. Sparfloxacin demonstrated increased activity against enterococci, staphylococci, pneumococci, and anaerobic cocci when compared with ciprofloxacin.

Proposed quality control and interpretive criteria for disk diffusion susceptibility testing with enoxacin.

The standardized disk diffusion test, in which a 10-micrograms enoxacin disk is used, was performed and microbroth dilution MICs were determined to establish individual test control values with Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, and S. aureus ATCC 29213. In addition, regression analysis correlating inhibitory zone diameter with MICs for approximately 400 gram-negative clinical isolates was performed. Based on linear regression and error rate-bounded analyses, criteria for the category calls of isolates are proposed.

Determination of mercury and organomercurial resistance in obligate anaerobic bacteria.

A methodology for determining the minimum inhibitory concentration of inorganic and organomercurial compounds for obligate anaerobic bacteria is described. A wide variation in the susceptibility of anaerobic clinical and sewage isolates was observed. Isolates of Bacteroides ruminicola and Clostridium perfringens resistant to mercury were examined for their plasmid content and ability to demonstrate inducible resistance. None of the resistant anaerobes contained any plasmids, while resistant facultative isolates from the same source contained several plasmids. In 24 h, resistant strains of clostridia and Bacteroides volatilized 20 and 43% of the 203Hg2+ added to cultures, while Escherichia coli R100 and a sewage isolate of Enterobacter cloacae volatilized 63 and 27%, respectively, of the added 203Hg2+. Attempts to induce mercury resistance in the aerobic isolates were successful, but no induction was seen in the anaerobes. Thus, mercury resistance in these anaerobic isolates was neither inducible nor plasmid mediated.

Efficacy of an enzyme immunoassay with uncentrifuged first-voided urine for detection of gonorrhea in males.

An enzyme immunoassay (Gonozyme; Abbott Laboratories, North Chicago, Ill.) for detection of Neisseria gonorrhoeae antigens was used to screen 184 urethral or uncentrifuged first-voided urine or both specimens from males and 78 cervical specimens. When compared with culture, the sensitivity and specificity of Gonozyme for cervical and urethral specimens were comparable to those in published reports. The sensitivity and specificity for urine specimens were 91.6 and 97.9%, respectively.

In vitro activities of enoxacin and 17 other antimicrobial agents against multiply resistant, gram-negative bacteria.

Enoxacin (CI-919) was evaluated for activity against 120 multiply resistant clinical isolates of the family Enterobacteriaceae and Pseudomonas aeruginosa. The MIC of enoxacin for 95% of the strains tested was less than or equal to 2 micrograms/ml. Approximately 90% of the isolates were susceptible to enoxacin, norfloxacin, ceftazidime, moxalactam, cefotaxime, cefoperazone, and amikacin. Marked resistance to the other seven antimicrobial agents tested was observed.

Rapid antimicrobial susceptibility testing of Gram-negative clinical isolates with the AutoMicrobic system.

Comparisons of the antimicrobial susceptibility patterns of clinical isolates of the family Enterobacteriaceae and Pseudomonas aeruginosa were made by using Kirby-Bauer disk diffusion, the MicroMedia system broth microdilution, and the AutoMicrobic system. The Kirby-Bauer system compared favorably with the MicroMedia system (95% essential correlation with 90% complete agreement). The AutoMicrobic system also compared favorably with both the Kirby-Bauer system (93% essential correlation with 87% complete agreement) and the MicroMedia system (97% essential correlation with 85% complete agreement). These data indicate that the AutoMicrobic system results are comparable to those of the MicroMedia and the Kirby-Bauer systems. Furthermore, the AutoMicrobic system offers a more rapid system (6 to 10 h), than the traditional systems, without sacrificing accuracy (16 to 24 h).