Hospital bronchoscopy-related pseudo-outbreak caused by a circulating Mycobacterium abscessus subsp. massiliense.

Adolfo Lutz Institute in Sao Paolo State performs mycobacterial identification for many healthcare units, and in 2008 identified a possible outbreak involving patients submitted to bronchoscopy at the same hospital. This study aimed to analyse the clonality of isolates. Mycobacterium abscessus subsp. massiliense isolated from 28 patients, water from one bronchoscope and water from four automated endoscope reprocessing machines presented high similarity by pulsed-field gel electrophoresis. This strain was not found in the water supply, and it was hypothesized that an infected patient contaminated the bronchoscope, with further false-positive cultures from subsequent patients.

Outbreak of surgical infection caused by non-tuberculous mycobacteria in breast implants in Brazil.

SUMMARY: We investigated an outbreak caused by non-tuberculous mycobacteria (NTM) related to breast implant surgery in the city of Campinas, Brazil, by means of a retrospective cohort and molecular epidemiological study. A total of 492 records of individuals having breast surgery in 12 hospitals were evaluated. Twelve isolates were analysed using four different molecular typing methods. There were 14 confirmed cases, 14 possible cases and one probable case. One probable, nine possible and 12 confirmed cases were included in a cohort study; all occurred in eight of the hospitals and the confirmed cases in five. Univariate analysis showed that patients who had had breast reconstruction surgery in hospitals A and B were more likely to have NTM infections. No risk factor was independently associated with NTM infection in the multivariate model. The isolates obtained from patients at each hospital showed different molecular patterns, excluding isolates from hospital C that repeatedly showed the same genotype for approximately one year. In conclusion, this outbreak was caused by polyclonal strains at different institutions, and in one hospital a unique genotype caused most cases. No specific risk factors were found.

Differentiation of Mycobacterium tuberculosis from other mycobacteria with rho-nitrobenzoic acid using MGIT960.

SETTING: Mycobacteria growth in media with the addition of inhibitory substances has been used in species identification. Growth of the Mycobacterium tuberculosis complex (MTC) is inhibited by rho-nitrobenzoic acid (PNB), whereas non-tuberculous mycobacteria (NTM) are resistant. OBJECTIVE: To develop a rapid PNB test using the automated BACTEC MGIT960 system and to evaluate its usefulness in the screening of mycobacterial isolates. DESIGN: PNB tests were performed in 93 MTC strains and 61 NTM strains from the Instituto Adolfo Lutz Culture Collection. PNB was added to Löwenstein-Jensen (LJ) medium and to BACTEC MGIT960 medium. RESULTS: The MTC strains were all PNB-susceptible, confirming the original identification. Among 10 NTM species, all were found to be resistant to PNB, except for one strain of M. kansasii and another of M. marinum. The median time to obtain presumptive identification of MTC by inhibition test in the BACTEC MGIT960 system was 6.3 days and for NTM it was 2.5 days. The presumptive identification of MTC in LJ was mostly obtained after day 20. CONCLUSION: The key finding of this analysis was the possibility of combining the traditionally accepted method proposed by Tsukamura and Tsukamura in 1964 with the modern, safe and rapid BACTEC MGIT960 methodology.

Application of four molecular typing methods for analysis of Mycobacterium fortuitum group strains causing post-mammaplasty infections.

A cluster of cases of post-augmentation mammaplasty surgical site infections occurred between 2002 and 2004 in Campinas, in the southern region of Brazil. Rapidly growing mycobacteria were isolated from samples from 12 patients. Eleven isolates were identified as Mycobacterium fortuitum and one as Mycobacterium porcinum by PCR-restriction digestion of the hsp65 gene. These 12 isolates, plus six additional M. fortuitum isolates from non-related patients, were typed by pulsed-field gel electrophoresis (PFGE) and three PCR-based techniques: 16S-23S rRNA internal transcribed spacer (ITS) genotyping; randomly amplified polymorphic DNA (RAPD) PCR; and enterobacterial repetitive intergenic consensus (ERIC) PCR. Four novel M. fortuitum allelic variants were identified by restriction analysis of the ITS fragment. One major cluster, comprising six M. fortuitum isolates, and a second cluster of two isolates, were identified by the four methods. RAPD-PCR and ITS genotyping were less discriminative than ERIC-PCR. ERIC-PCR was comparable to PFGE as a valuable complementary tool for investigation of this type of outbreak.

A population-based study of drug resistance and transmission of tuberculosis in an urban community.

SETTING: A low-income neighborhood of Sao Paulo, Brazil. OBJECTIVE: To determine the incidence, risk factors and transmission patterns of multidrug-resistant tuberculosis (MDR-TB). DESIGN: Prospective longitudinal study of patients with pulmonary TB (PTB). METHODS: Sputum culture-confirmed patients with PTB were recruited between March 2000 and May 2002. Bivariate and multivariate logistic regression analyses were performed to identify factors associated with MDR-TB. Mycobacterium tuberculosis isolates were tested for drug susceptibility and typed by IS6110-RFLP analysis. RESULTS: Of 420 patients, respectively 71% and 27% were new and previously treated; 15.5% of the patients' M. tuberculosis isolates were resistant to at least one drug; of these, 11% and 27% were found among new and previously treated cases, respectively. Respectively 1% and 16.7% of the new and previously treated cases were MDR-TB. RFLP analysis showed that new transmission of MDR strains was uncommon. By multivariate logistic regression analysis, previous TB and hospitalization in the 24 months before TB diagnosis were identified as independent predictors of MDR-TB. CONCLUSIONS: The results showed an intermediate level of MDR-TB incidence in a neighborhood of Sao Paulo and identified predictors that can be targeted for intervention by national and local TB control programs.

Transmission of tuberculosis in an endemic urban setting in Brazil.

SETTING: Two out-patient facilities in São Paulo, Brazil. OBJECTIVE: To study the transmission pattern of tuberculosis (TB) among human immunodeficiency virus (HIV) infected and uninfected persons in a setting endemic for TB. DESIGN: A prospective study comparing HIV-seropositive and -seronegative TB patients identified consecutively between 1 March 1995 and 1 April 1997. The patients were stratified according to their Mycobacterium tuberculosis isolate IS6110 RFLP patterns. Risk factors were sought for infection with an RFLP cluster pattern strain, inferred to represent recent transmission. RESULTS: Fifty-eight (38%) of 151 HIV-seropositive patients and 36 (25%) of 142 HIV-seronegative patients were infected with M. tuberculosis isolates that belonged to cluster patterns (OR 1.84, 95% CI 1.08-3.13). Multidrug-resistant (MDR) strains were isolated from 19 patients, all of whom were HIV seropositive; 12 (63%) of these, and 46 (35%) of 132 drug-susceptible isolates had cluster patterns (OR 3.20, 95% CI 1.08-9.77). CONCLUSION: In a TB-endemic urban setting in Brazil, the proportion of cases resulting from recent transmission appears to be greater among HIV-seropositive than among HIV-seronegative patients. A large proportion of MDR-TB (63%) cases was caused by strains that had cluster RFLP patterns, suggesting recent transmission of already resistant organisms. This type of knowledge regarding TB transmission may help to improve locally appropriate TB control programs.