In 2000, an outbreak of Mycobacterium fortuitum furunculosis affected customers using whirlpool footbaths at a nail salon. We swabbed 30 footbaths in 18 nail salons from 5 California counties and found mycobacteria in 29 (97%); M. fortuitum was the most common. Mycobacteria may pose an infectious risk for pedicure customers.

Microscopic examination of respiratory specimens for acid-fast bacilli (AFB) plays a key role in the initial diagnosis of tuberculosis, monitoring of treatment, and determination of eligibility for release from isolation. The objective of this study was to compare the sensitivity obtained with smears for detection of AFB (AFB smears) made directly from respiratory specimens (direct AFB smears) to that obtained with parallel smears made from concentrates of the specimens (concentrated AFB smears). A total of 2,693 specimens were evaluated; 1,806 were from the University of California Irvine Medical Center Medical Microbiology Laboratory (UCIMC), which serves a tertiary-care hospital with outpatient clinics, and 887 were from the Microbial Disease Laboratory at the California Department of Public Health (MDL), which receives specimens from outpatient facilities and clinics on Pacific islands. Of the 353 AFB culture-positive specimens at UCIMC, there was a statistically significant difference in the sensitivity of the direct AFB smear (34%) and that of the smear made from the concentrated specimen (58%) (P < 0.05). This was also true for the 208 specimens positive for Mycobacterium tuberculosis, for which the sensitivity of the direct smear was 42% (87 of 208) and that for the smear made from the concentrated specimen was 74% (154 of 208). At MDL, where all but 1 of the 45 culture-positive specimens grew M. tuberculosis, the sensitivity of the smear made from the concentrated specimen was 93% (42 of 45) and was not significantly higher than the sensitivity of the direct smear, which was 82% (37 of 45). By combining the results from both laboratories, 42 patients from whom at least three specimens were received were culture positive for M. tuberculosis. The cumulative results for the initial three specimens from these patients showed that the direct smear detected M. tuberculosis in 81% of these patients, whereas the smear made from the concentrate detected M. tuberculosis in 91% of these patients. In summary, when all culture-positive specimens are considered, the sensitivity of the direct smear compared to that of a smear made from the concentrated specimen was significantly different overall in the two different laboratory settings. However, this difference was reduced only if the cumulative results for the initial three specimens received from patients who were culture positive for M. tuberculosiswere evaluated.

Five Mycobacterium tuberculosis complex isolates in California were identified as M. africanum by spoligotyping, single nucleotide polymorphisms, a deletion mutation, and phenotypic traits, confirming it as a cause of tuberculosis in the United States. Three of the five patients from whom M. africanum was isolated had lived in Africa.M ycobacterium africanum is a member of the M. tuberculosis complex, which has been isolated from humans in equatorial Africa. The disease produced by M. africanum is similar to that caused by M. tuberculosis or M. bovis, and like M. tuberculosis, this organism is likely spread by aerosol transmission (1). Human tuberculosis caused by M. africanum has been reported in Europe (2,3). However, we are unaware of previous reports of disease caused by M. africanum in the United States. The StudyM. africanum may be identified by spoligotyping (4), by specific deletion mutations (5), DNA fingerprinting by IS6110 restriction fragment length polymorphisms (RFLP) (4), or a combination of these methods. Isolates were initially identified as M. tuberculosis complex by using the AccuProbe system (Gen-Probe; San Diego, CA). The isolates then underwent IS6110-based RFLP fingerprinting. The RFLP analyses were performed according to the method of van Embden et al. (6). In addition to providing genotyping results, RFLP fingerprinting confirmed the identification obtained with Accuprobe.All strain typing was performed in-house at the Microbial Diseases Laboratory, California Department of Health Services. This laboratory has compiled a database (Genomic Solutions BioImage) of approximately 7,000 DNA fingerprints, typed by IS6110 RFLP (6,7) from throughout California; most are from the San Francisco Bay area. Three isolates (from patients A, B, and C) were initially suspected of being M. africanum because of an epidemiologic association with Africa. These isolates were fingerprinted by IS6110 RFLP and by spoligotyping (8).All three were found to have the "signature" spoligotype described by Viana-Niero et al. as being characteristic of M. africanum (4), namely, they were missing spacers 8, 9, and 39 but had spacers 40-43. Using BioImage software, we searched the laboratory's database for IS6110 fingerprints that matched those of the three cases with an African connection. This search yielded an additional two matches, cases D and E. Isolates from cases D and E were then genotyped by using spoligotyping and found to have the M. africanum signature spoligotype.The five M. africanum isolates were further characterized by performing standard biochemical identification tests and testing for susceptibility to pyrazinamide (PZA). Niacin production and nitrate reduction were detected as described by Kent and Kubica (9). Susceptibility to PZA was determined by using the BACTEC radiometric assay performed according to the method of Salfinger et al. (10). The M. africanum isolates were then examined to determine whether they had the RD9 deletion and specific oxyR and katG sequence mutations.Brosch et al. had repor...