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Rapid diagnosis of bacteroides infections by indirect immunofluorescence assay of clinical specimens
were obtained through an endotracheal tube, one at bronchoscopy, and the other two were expectorated specimens. In addition, two open-lung biopsies and the sediment from a bronchial wash from 3 confirmed cases were positive. The major shortcoming of this test on sputum obviously is that only 24% of patients shown to have the disease by other critet,ia had tests that were positive. The article suggests that transtracheal aspirates oi- sputum induction may increase the sensitivity of this test. D. L. Kasper et al. 1979. Rapid diagnosis of bacteroides infections by indirect immunofluorescence assay of clinical specimens. Lancet 1:239-242. Forty-three specimens from various sites were examined directly by indirect immunofluorescense assay (IFA) using antisera against the capsular polysaccharide of B.fragilis and with pooled antisera against a number of serotypes of Bacteroides species (including all of the formerB.fragilis subspecies). The findings were compared to those with routine anaerobic bacteriology and gas liquid chromatography. IFA was sensitive (100%) and specific (90%) as a means of identifying B. fragilis. The pooled serum was sensitive but less specific, although it had the advantage of detecting other bacteroides species. IFA gave 9.7% false-positives, and no false-negatives, and its predictive value on a clinical specimen was 80%. A. L. B a r r y et al. 1978. Aerobic and anaerobic susceptibility tests with three tetracyclines. Reassessment of the
"class concept" of disk testing. Am. J. Clin. Path. 70:821-825. The authors performed Kirby-Bauer and agar dilution tests with tetracycline, doxycycline, and minocycline. All strains susceptible to a tetracycline disk were susceptible to the analogs. Some strains in the resistant or intermediate range to tetracycline were susceptible or moderately susceptible to the analogs by agar dilution methods. However, disk tests with doxycycline or minocycline were often unproductive with these organisms since they gave indeterminate results. The authors concluded that tetracycline disks predict susceptibility to the other tetracyclines reasonably well. S. P. Sherman, and J. A. Washington. 1978. Pyridoxine inhibition of a symbiotic Streptococcus. Am. J. Clin. Path. 70:689-690. A symbiotic a-hemolytic streptococcus that showed satellitism about a Staphylococcus aureus was recovered from blood cultures of a patient with endocarditis. Pyridoxine, which previously has been reported to be required for growth of symbiotic streptococci, was found to inhibit the growth of this organism. D. M. Musher et al. 1979. Two forms of Staphylococcus attreus in blood of patients with staphylococcal sepsis. J. Clin. Microbiol. 9:23-27. Two different forms ofS. attreus were isolated from the blood of two patients. In each patient one colony form was hemolytic and the other nonhemolytic,
although both had the same biochemicals, phage types, antibiotic susceptibility and virulence for mice. This is not an unusual phenomenon, and the authors' evidence suggests that it isn't particularly ominous. P. K. Goldberg et al. 1979. Incidence and significance of candiduria. JAMA 241:582-584. Feeling that the colony count end point of 100,000 organisms/ml has been used without careful evaluation for the diagnosis of renal candidiasis, the authors performed a prospective study on 1,000 urine samples from patients without candidiasis. The results were compared with those from histologically proven cases of renal candidiasis. Urine samples were spread by calibrated loop onto Sabouraud's dextrose agar plates containing gentamicin for quantitation of Candida, and the sediment of the centrifuged urine was also plated onto Nickerson agar slants. Candiduria frequency varied from a low of 4% in men to a high of 39% in girls* during their second week of antibiotic therapy. The overall mean colony count in all positive specimens was 1300 _ 1500. The mean colony count in clean catch specimens from six proven cases was 24,000 _ 12,000. The difference in colony counts from proven and unproven cases was statistically significant. The authors believe that c6unts greater than 10,000 organisms/ml require further investigation. * Note: "girls" is correctaboveand not evidenceof malechauvinism.
"class concept" of disk testing. Am. J. Clin. Path. 70:821-825. The authors performed Kirby-Bauer and agar dilution tests with tetracycline, doxycycline, and minocycline. All strains susceptible to a tetracycline disk were susceptible to the analogs. Some strains in the resistant or intermediate range to tetracycline were susceptible or moderately susceptible to the analogs by agar dilution methods. However, disk tests with doxycycline or minocycline were often unproductive with these organisms since they gave indeterminate results. The authors concluded that tetracycline disks predict susceptibility to the other tetracyclines reasonably well. S. P. Sherman, and J. A. Washington. 1978. Pyridoxine inhibition of a symbiotic Streptococcus. Am. J. Clin. Path. 70:689-690. A symbiotic a-hemolytic streptococcus that showed satellitism about a Staphylococcus aureus was recovered from blood cultures of a patient with endocarditis. Pyridoxine, which previously has been reported to be required for growth of symbiotic streptococci, was found to inhibit the growth of this organism. D. M. Musher et al. 1979. Two forms of Staphylococcus attreus in blood of patients with staphylococcal sepsis. J. Clin. Microbiol. 9:23-27. Two different forms ofS. attreus were isolated from the blood of two patients. In each patient one colony form was hemolytic and the other nonhemolytic,
although both had the same biochemicals, phage types, antibiotic susceptibility and virulence for mice. This is not an unusual phenomenon, and the authors' evidence suggests that it isn't particularly ominous. P. K. Goldberg et al. 1979. Incidence and significance of candiduria. JAMA 241:582-584. Feeling that the colony count end point of 100,000 organisms/ml has been used without careful evaluation for the diagnosis of renal candidiasis, the authors performed a prospective study on 1,000 urine samples from patients without candidiasis. The results were compared with those from histologically proven cases of renal candidiasis. Urine samples were spread by calibrated loop onto Sabouraud's dextrose agar plates containing gentamicin for quantitation of Candida, and the sediment of the centrifuged urine was also plated onto Nickerson agar slants. Candiduria frequency varied from a low of 4% in men to a high of 39% in girls* during their second week of antibiotic therapy. The overall mean colony count in all positive specimens was 1300 _ 1500. The mean colony count in clean catch specimens from six proven cases was 24,000 _ 12,000. The difference in colony counts from proven and unproven cases was statistically significant. The authors believe that c6unts greater than 10,000 organisms/ml require further investigation. * Note: "girls" is correctaboveand not evidenceof malechauvinism.