Application of the Roche Amplicor Mycobacterium tuberculosis (PCR) test to specimens other than respiratory secretions.

The ability of the Roche AMPLICOR Mycobacterium tuberculosis (MTB) test to detect M. tuberculosis in specimens other than respiratory secretions was evaluated. A total of 249 specimens from 219 patients were tested. Of these, 12 specimens grew isolates of the M. tuberculosis complex and four grew isolates of the M. avium complex. The AMPLICOR MTB test was positive for 10 of the 12 specimens which grew M. tuberculosis and for three specimens which were culture negative. Two of the latter specimens were from patients with a clinical diagnosis of tuberculosis and with multiple sputum specimens which grew M. tuberculosis. Four specimens grew M. avium complex isolates, and all yielded negative AMPLICOR MTB test results. The sensitivity, specificity, and positive and negative predictive values for the AMPLICOR MTB test were 85.7%, 99.5%, 92.3%, and 99.1%, respectively. Our data indicate that the AMPLICOR MTB test will permit the rapid detection of M. tuberculosis in specimens other than respiratory secretions.

Rapid diagnosis of pulmonary tuberculosis by using Roche AMPLICOR Mycobacterium tuberculosis PCR test.

A rapid PCR-based test for the diagnosis of pulmonary tuberculosis, the Roche AMPLICOR Mycobacterium tuberculosis test (AMPLICOR MTB), was evaluated. Results from AMPLICOR MTB were compared with culture results and the final clinical diagnosis for each patient. A total of 985 specimens from 372 patients were tested. When AMPLICOR MTB results were compared with resolved results, i.e., a specimen grew M. tuberculosis or was obtained from a patient with a clinical diagnosis of tuberculosis, the sensitivity, specificity, positive predictive value, and negative predictive value for the AMPLICOR MTB test were 66.7, 99.6, 91.7, and 97.7%, respectively. These results were comparable to those obtained from culture. Test results were available approximately 6.5 h after specimen receipt in the laboratory. Our data demonstrate that AMPLICOR MTB will provide rapid, valuable information for the diagnosis and control of tuberculosis.

Acinetobacter calcoaceticus anitratus outbreak in the intensive care unit traced to a peak flow meter.

BACKGROUND: A cluster of seven cases of Acinetobacter caleoaceticus anitratus in a community teaching hospital intensive care unit was discovered (the seventh case was located in a step-down unit next to an infected patient recently transferred from the intensive care unit.) METHODS: An outbreak investigation, including detailed epidemiologic, clinical, and laboratory investigation, was performed. RESULTS: A single strain of A. calcoaceticus anitratus was responsible for infection in all seven patients. All patients had tracheostomies, were in respiratory failure, and were ventilator dependent. Patients ranged in age from 27 to 81 years. No common causative variable or explanatory findings were present except that the same peak flow meter (manual weaning criteria machine) was used to facilitate weaning all seven patients from mechanical ventilation. Culture of the mouthpiece isolated a A. calcoaceticus anitratus strain with the identical susceptibility pattern and biochemical profile as that from the infected patients. CONCLUSION: A. calcoaceticus anitratus was transmitted by a peak flow meter nosocomially to seven patients receiving mechanical ventilation. Disposable mouthpieces were introduced to prevent cross-contamination. A 2% glutaraldehyde solution was used to disinfect the machine between uses. No further outbreaks of A. calcoaceticus anitratus pneumonia were identified during 3 years of follow-up.

Neisseria sicca endocarditis with embolic phenomena.

Two patients with poor oral hygiene developed Neisseria sicca endocarditis, one after probable intravenous drug abuse and Staphylococcus aureus endocarditis and the other after a periodontal surgical procedure. Both experienced significant embolic phenomena and both required 6 or more weeks of intravenous antibiotic therapy. The diagnosis of N. sicca endocarditis must be considered when this organism is isolated from blood cultures in patients with emboli.

Evaluation of the Roche Septi-Chek AFB system for recovery of mycobacteria.

The Septi-Chek AFB system for the recovery of mycobacteria from clinical specimens was compared with a conventional approach using Lowenstein-Jensen and Middlebrook 7H11 agars. A total of 1,532 clinical specimens were analyzed; 132 yielded mycobacteria. Mycobacterium tuberculosis and Mycobacterium avium complexes were the predominant isolates. With the conventional combination of Lowenstein-Jensen and 7H11 agars, 75.8% of the isolates were recovered; the Septi-Chek AFB allowed recovery of 100% of the isolates. Septi-Chek AFB required less time for the detection of mycobacteria than did the conventional media.

Collaborative feasibility study of a biphasic system (Roche Septi-Chek AFB) for rapid detection and isolation of mycobacteria.

A study to delineate the feasibility of a biphasic-culture approach for detection and isolation of mycobacteria from clinical specimens except blood was conducted in four medical centers. The biphasic system (Septi-Chek AFB, Roche Diagnostic Systems, Nutley, N.J.) was compared with conventional mycobacterial isolation media and the BACTEC system. Septi-Chek AFB showed the highest degree of mycobacterial recovery. In addition, Septi-Chek AFB consistently shortened the time required for recovery of mycobacteria from clinical specimens and supported the growth of small inoculum numbers of stock cultures of 14 mycobacterial species. The study indicates the feasibility and potential advantages of the biphasic approach for detection and isolation of mycobacteria.

In vitro activities of cefoperazone and sulbactam singly and in combination against cefoperazone-resistant members of the family Enterobacteriaceae and nonfermenters.

Among 28,000 isolates of the family Enterobacteriaceae and nonfermenters isolated at multiple medical centers, 1,084 (4%) were resistant to cefoperazone (MIC, greater than or equal to 64 micrograms/ml) and 1,711 (6%) exhibited cefoperazone MICs of 2 to 32 micrograms/ml. Ninety-six percent of these 2,795 isolates produced beta-lactamase, as determined by the nitrocefin test. Sulbactam alone (8 micrograms/ml) was inactive against 99.6% of the isolates other than Acinetobacter calcoaceticus and Pseudomonas cepacia. Sulbactam enhanced the activity of cefoperazone against 56% of the isolates of the family Enterobacteriaceae and 44% of the nonfermenters. In the presence of sulbactam concentrations of less than or equal to 8 micrograms/ml, 65% of the cefoperazone-resistant isolates had reductions in cefoperazone MICs of greater than or equal to 2 log2 dilution steps and were susceptible to less than or equal to 32 micrograms/ml. Antagonism was not observed.

Squamous cell carcinoma of the nail bed.

Squamous cell carcinoma of the nail bed is an unusual malignancy of low virulence that is often misdiagnosed as a benign condition. Early diagnosis by biopsy, especially in patients with histories of repeated trauma, chronic infection, or exposure to irradiation or other predisposing factors, may lead to treatment and prevent the tumor from metastasizing.

False-positive latex agglutination test for Neisseria meningitidis groups A and Y caused by povidone-iodine antiseptic contamination of cerebrospinal fluid.

The cerebrospinal fluid of a patient yielded a positive latex agglutination test for Neisseria meningitidis groups A and Y. The latex agglutination results were not consistent with clinical and other laboratory findings. An investigation determined that the positive agglutination test was caused by contamination of the cerebrospinal fluid with povidone-iodine during the lumbar puncture.

In vitro activity of cefoperazone/sulbactam and other antimicrobials against anaerobic bacteria.

Sulbactam inhibits the hydrolytic activity of several, clinically important beta-lactamases including those produced by anaerobic bacteria. This study was undertaken to determine the effect of sulbactam on the activity of cefoperazone against 250 anaerobic bacteria including 174 isolates belonging to the Bacteroides fragilis group and to compare the activity of cefoperazone/sulbactam with other antimicrobial agents. beta-lactamase activity was detected in 98% of the isolates of the Bacteroides fragilis group but not in the other species evaluated. Antagonistic activity between cefoperazone and sulbactam was not observed with any of the species. Forty-two percent of the isolates belonging to the B. fragilis group were resistant to cefoperazone. Ninety-four percent of these were converted to either the susceptible or moderately susceptible range upon the addition of sulbactam. Sixty-seven percent were susceptible to the combination cefoperazone/sulbactam and 27% were moderately susceptible. Overall, metronidazole and chloramphenicol were the most active antimicrobials. Significant differences in the antimicrobial susceptibility patterns of members of the B. fragilis group were observed. Sulbactam demonstrated some intrinsic activity against all of the species tested.

In vitro activity of ampicillin/sulbactam against enterococci determined by the time-kill method.

Time-kill studies demonstrated that at clinically achievable serum concentrations, ampicillin/sulbactam was equivalent in activity to ampicillin alone against non-beta-lactamase producing isolates of Enterococcus faecalis and Enterococcus faecium. Sulbactam possessed no antibacterial activity against these organisms. It is not yet known if the activity of ampicillin will be increased with the addition of sulbactam when tested against beta-lactamase-producing enterococci.

Achromobacter xylosoxidans (Alcaligenes xylosoxidans subsp. xylosoxidans) meningitis associated with a gunshot wound.

The microbiological and clinical features of a case of Achromobacter xylosoxidans (Alcaligenes xylosoxidans subsp. xylosoxidans) meningitis associated with a gunshot wound are described. To our knowledge, this is the third confirmed case report of meningitis caused by this organism.

Novel application of video image processing to biochemical and antimicrobial susceptibility testing.

ALADIN (Analytab Products, Plainview, N.Y.) is an automated instrument that uses video imaging (computer-assisted guided video camera) for the determination of biochemical and antimicrobial susceptibility test reactions. This collaborative investigation compared video-generated results obtained with ALADIN with visually determined findings. Both approaches were used to view identical reactions. Overall agreement for biochemical and antimicrobial susceptibility tests was greater than 95%. This study demonstrates that video imaging is an acceptable approach for determining microbial responses to biochemical and antimicrobial agents and may provide, with appropriate computer modifications, more accurate and reproducible results than are possible by visual scrutiny.

Collaborative clinical laboratory evaluation of an individual MIC strip system.

Susceptibility results obtained with individualized MIC strips (MICRO-MIC) agreed with the standard microdilution broth method at a level of 96% or greater for each of the 10 antimicrobial agents tested.

Quantitative antimicrobial susceptibility test for Streptococcus pneumoniae using inoculum supplemented with whole defibrinated sheep blood.

The National Committee for Clinical Laboratory Standards recommends the use of lysed horse blood-supplemented Mueller-Hinton broth for determining the quantitative antimicrobial susceptibility of Streptococcus pneumoniae. This procedure may be difficult for laboratories using previously prepared or commercial MIC systems. Therefore, a study was undertaken to determine whether previously prepared microdilution trays containing Mueller-Hinton broth without blood could be used for determining the antimicrobial susceptibility of S. pneumoniae by adding whole defibrinated sheep blood to the bacterial suspension used to inoculate the trays. The presence of alpha-hemolysis was used as an indicator of bacterial growth. One hundred isolates of S. pneumoniae selected to represent a distribution of susceptibility patterns were tested by the National Committee for Clinical Laboratory Standards method and the sheep blood-supplemented-inoculum method. Greater than 94% agreement between the two methods was achieved. The sheep-blood-supplemented-inoculum procedure was highly reproducible and easy to perform and provides an acceptable alternative for determining the MICs for S. pneumoniae for laboratories using previously prepared or commercial microdilution systems.

Two fatal cases of type E adult food-borne botulism with early symptoms and terminal neurologic signs.

Type E botulism, one of the least common forms of botulinal intoxication on the East Coast of the United States, is described for two elderly patients with chronic underlying disease. Both patients consumed tainted kapchunka, a salted, ungutted whitefish. Gastrointestinal symptoms and signs were prominent, but neurologic complaints, although noted soon after the consumption of the fish in one patient, did not progress until late in the course of the patient's illness. One patient exhibited both urinary retention, which was reported mainly in one outbreak of type E botulism (M.G. Koenig, A. Spickard, M.A. Cardella, and D.E. Rogers, Medicine [Baltimore] 43:517-545, 1964), and muscular fasciculations, which have been rarely reported.

Enzyme-linked immunosorbent assay for detection of streptolysin O antibodies.

An enzyme-linked immumosorbent assay (ELISA), based upon the detection of streptolysin O antibodies in human sera, was developed. Disposable polystyrene tubes, sensitized with streptolysin O antigen, were used as the test vehicles. Corresponding antibodies, present in test sera, were detected by binding of the antibodies to goat anti-human immunoglobulin G conjugated to horseradish peroxidase. Demonstration of bound conjugate was accomplished by monitoring peroxidase activity spectrophotometrically at 450 nm, using 5-aminosalicylic acid as the indicator. A total of 97 human sera, previously analyzed by means of the anti-streptolysin O titration technique, were evaluated with the ELISA procedure. A direct quantitative relationship, found to be statistically significant, was demonstrated between Todd units and absorbance values obtained with ELISA.

Evaluation of the BIOGRAM antimicrobial susceptibility test system.

BIOGRAM is an antimicrobial susceptibility test system for the determination of MICs from the standard disk diffusion test zone diameters. The system was challenged with 511 recent clinical isolates of members of the family Enterobacteriaceae, nonfermentative gram-negative bacteria, staphylococci, and enterococci. Results were compared with those obtained with the broth microdilution method. Appropriate control organisms were included with each test series. A total of 10,085 organism-drug combinations were evaluated. BIOGRAM demonstrated an overall correlation of 95.9% with the reference broth microdilution method.