Faculty Bibliography

Five hundred five blood samples for culture were processed in the Isolator lysis-centrifugation system and were then inoculated into a Mycobacteria Growth Indicator Tube (MGIT) and onto a Lowenstein-Jensen (L-J) slant. Forty-nine isolates of Mycobacterium avium complex and three isolates of Mycobacterium tuberculosis were recovered from 50 of the blood culture specimens. Forty-five isolates from 43 specimens were recovered in the MGIT, with a mean time to detection of 21 days. Forty-one isolates from 40 specimens were recovered in the L-J slants, and the mean time to detection was 36 days. Nine specimens were positive in the MGIT alone, while seven specimens were positive only in L-J medium

Tuberculosis (TB) is one of the most important infections worldwide, with an estimated incidence of 10 million active cases per year. Rifampicin is a key component of the first-line therapy used in the treatment of tuberculosis. In Escherichia coli and Mycobacterium leprae, rifampicin has been shown to inhibit the beta subunit of RNA polymerase. The gene (rpoB) encoding this enzyme has been described in both species. We report the isolation of the homologous functional rifampicin resistance gene from M. tuberculosis. A library was constructed with 15 to 25 kb BamHI-digested DNA fragments from a rifampicin-resistant M. tuberculosis clinical isolate that was ligated into an E. coli-mycobacterial shuttle plasmid. Southern analysis of BamHI-digested DNA from 200 recombinant plasmids was performed and filters were hybridized to a 411 bp fragment of the beta subunit of RNA polymerase from M. tuberculosis. Only DNA from one plasmid (#86) hybridized, which suggested that the gene is found as a single copy per genome. This plasmid was able to transfer rifampicin resistance to sensitive M. smegmatis and thus codes for a functional genetic unit. Sequence analysis in the expected 'hotspot' region in eight rifampicin-resistant M. tuberculosis strains (including one multidrug-resistant strain) revealed two novel mutations as well as others previously described

We recently observed a striking increase in multidrug-resistant tuberculosis (MDR-TB) among patients admitted to the Chest Service at Bellevue Hospital Center in New York. We reviewed the laboratory susceptibility test results of 4,681 tuberculosis (TB) cases over the past 20 years, Combined resistance to isoniazid and rifampin increased from 2.5 percent in 1971 to 16 percent in 1991 with higher rates noted for individual drugs. We reviewed the medical records of 100 patients with drug-resistant TB, finding that these individuals were predominantly less than 40 years of age, minority, male, jobless, undomiciled, with a high percentage of drug abuse and human immunodeficiency virus infection. We conclude that the epidemics of AIDS and TB are complicated by a third epidemic of MDR-TB. This third epidemic requires urgent attention to achieve more rapid diagnosis, to develop new therapeutic regimens, and to address the social and hospital environment ot care for these individuals

Objective: Although the incidence of reported cases of toxic shock syndrome (TSS) has declined in recent years, the disease continues to occur in menstruating women using the newer, less-absorbent tampons or barrier contraceptives. Extant tampons and other vaginal devices were tested for the ability to induce TSS toxin-1 (TSST-1) by a TSS strain of Staphylococcus aureus MN8, a known high-toxin producer. Tested for the first time were 20 varieties of tampons, including 2 all-cotton brands newly introduced in the United States, a polyurethane contraceptive sponge, a latex diaphragm, and a polymer menstrual collection cup.Methods: All products were washed in sterile distilled water prior to use to reduce the effect of leachable chemicals. Duplicate experiments with unwashed products were also performed. Entire tampons and other test products were immersed in brain heart infusion broth plus yeast extract (BHIY) and inoculated with S. aureus MN8, a known TSST-1 producer. After incubation, the culture supernatants were assayed for TSST-1 by gel immunodiffusion.Results: Except for all-cotton tampons, greater amounts of TSST-1 were detected in the supernatant fluid of washed tampons than detected in those which were not washed. While TSST-1 levels in unwashed non-cotton tampons ranged from 0.5 to 8 mug/ml, when these products were washed, TSST-1 levels increased to 2-32 mug/ml. In all-cotton tampons, whether washed or not, there was no detectable TSST-1.Conclusions: The propensity for all-cotton tampons not to amplify TSST-1 in vitro suggests they would lower the risk for tampon-associated TSS

Five hundred urine specimens were selected at random and screened for bacteriuria by a DNA probe method, FlashTrack (Gen-Probe, San Diego, Calif.), and an automated bioluminescence method, UTIscreen (Los Alamos Diagnostics, Los Alamos, N.M.), and the results were compared with those of the semiquantitative plate culture method. The performance of each test versus culturing was evaluated at colony counts of greater than or equal to 10(4), greater than or equal to 5 x 10(4), and greater than or equal to 10(5) CFU/ml. Since the interpretive breakpoint of each test was user selectable, the results were reported as receiver operator characteristic curves. Optimum interpretive breakpoints were determined for each test at each colony count by calculating a performance index that emphasized sensitivity over specificity in a 70:30 ratio. Although both tests had less-than-optimal sensitivities and specificities, the performance of FlashTrack was significantly better than that of UTIscreen at two of the three colony counts (10(4) and 10(5) CFU/ml); however, FlashTrack costs more and is a labor-intensive procedure. Neither method was evaluated for the detection of colony counts of less than 10(4) CFU/ml

A retrospective review of charts of 156 human immunodeficiency virus-infected children cared for during a 7.5-year period revealed 11 episodes of disseminateed candidiasis (DC) occurring in 11 patients (7%). All 11 patients developed the fungal infection in the context of advanced human immunodeficiency virus infection. All but one were hospital-acquired, occurring at a mean of 2.3 months after admission. Ten patients had been febrile for more than 14 days before diagnosis. Previous oral thrush and central venous catheters (73 and 82% of patients) represented major predisposing factors for development of DC. Neutropenia (2 of 11 patients) did not represent a major risk factor for DC. Candida albicans was isolated in 9 patients, Rhodotorula minuta in 1 patient and 1 fungal isolate could not be identified. Sources of isolation were blood (8 of 11 patients), central venous catheters (3 of 11) and urine (2 of 11). Lungs (6 of 11 patients), esophagus (5 of 11) and brain, heart and kidneys (3 patients each) were the organs most often involved in DC. Antemortem diagnosis was achieved in only 7 (64%) patients; none of the 4 patients with DC diagnosed postmortem had been treated before death. Seven patients were treated with amphotericin B; 6 of them died but only 3 were treated for more than 7 days of therapy. The overall mortality was 90% (10 of 11 patients). In all 20% of the 50 human immunodeficiency virus-infected children who died at our hospital during the study period had an episode of DC in close proximity to their death. DC was considered the direct cause of death in 4 of 10 children