Relapse more common than reinfection in recurrent tuberculosis 1-2 years post treatment in urban Uganda.

OBJECTIVE: To determine the proportion of recurrent tuberculosis (TB) due to relapse with the patient's initial strain or reinfection with a new strain of Mycobacterium tuberculosis 1-2 years after anti-tuberculosis treatment in Uganda, a sub-Saharan TB-endemic country. DESIGN: Records of patients with culture-confirmed TB who completed treatment at an urban Ugandan clinic were reviewed. Restriction fragment length polymorphism (RFLP) patterns were used to determine relapse or reinfection. Associations between human immunodeficiency virus (HIV) positivity and type of TB recurrence were determined. RESULTS: Of 1701 patients cured of their initial TB episode with a median follow-up of 1.24 years, 171 (10%) had TB recurrence (8.4 per 100 person-years). Rate and risk factors for recurrence were similar to other studies from sub-Saharan Africa. Insertion sequence (IS) 6110-based RFLP of paired isolates from 98 recurrences identified 80 relapses and 18 reinfections. Relapses among HIV-positive and -negative patients were respectively 79% and 85% of recurrences. CONCLUSIONS: Relapse was more common and presented earlier than reinfection in both HIV-positive and -negative TB patients 1-2 years after completing treatment. These findings impact both the choice of retreatment drug regimen, as relapsing patients are at higher risk for acquired drug resistance, and clinical trials of new TB regimens with relapse as clinical endpoint.

Beijing family Mycobacterium tuberculosis strains differ in their intracellular growth in THP-1 macrophages.

SETTING: Previous studies have shown that isolates from cases in IS6110 restriction fragment length polymorphism (RFLP) clusters that have persisted over several years and are widely distributed grow significantly faster in macrophages than isolates from cases with unique RFLP patterns. As members of the Beijing family of Mycobacterium tuberculosis are widely distributed and have been responsible for several large outbreaks, it has been suggested that this genotype may have a selective advantage over other strains. OBJECTIVE: To determine whether rapid growth in macrophages is a common characteristic of Beijing family strains. DESIGN: T-helper precursor-1 human macrophages were infected with various Beijing family strains, and intracellular growth and tumor necrosis factor alpha (TNF-alpha) secretion were assessed. Strains differed in their genotype, with IS6110 copy number ranging from 9 to 22. RESULTS: Strains demonstrated a range of growth phenotypes over the 7-day infection period. Three grew significantly more slowly than the other strains, whereas the fastest growth was observed consistently with isolates of strain 210. CONCLUSION: Rapid growth in macrophages is not a common characteristic of all Beijing strains. Few Beijing strains are as virulent as strain 210. The growth advantage is consistent with strain 210 having persisted many years in different locations and having caused many outbreaks.

Association between Mycobacterium tuberculosis Beijing/W lineage strain infection and extrathoracic tuberculosis: Insights from epidemiologic and clinical characterization of the three principal genetic groups of M. tuberculosis clinical isolates.

Clinical strains of Mycobacterium tuberculosis can be divided into three principal genetic groups based on the single-nucleotide polymorphisms at the katG gene codon 463 and the gyrA gene codon 95. One subgroup of genetic group 1, the Beijing/W lineage, has been widely studied because of its worldwide distribution and association with outbreaks. In order to increase our understanding of the clinical and epidemiological relevance of the genetic grouping of M. tuberculosis clinical strains and the Beijing/W lineage, we investigated the genetic grouping of 679 clinical isolates of M. tuberculosis, representing 96.3% of culture-confirmed tuberculosis cases diagnosed in Arkansas between January 1996 and December 2000 using PCR and DNA sequencing. We assessed the associations of infections by different genetic groups of M. tuberculosis strains and infection by the Beijing/W lineage strains with the clinical and epidemiological characteristics of the patients using chi-square tests and multivariate logistic regression analysis. Of the 679 study isolates, 676 fell into one of the three principal genetic groups, with 63 (9.3%) in group 1, 438 (64.8%) in group 2, and 175 (25.9%) in group 3. After adjusting for potential confounding of age, gender, race/ethnicity, human immunodeficiency virus serostatus, and plcD genotype in a multivariate logistic regression model, patients infected by the Beijing/W lineage isolates were nearly three times as likely as patients infected with the non-Beijing/W lineage isolates to have an extrathoracic involvement (odds ratio [95% confidence interval], 2.85 [1.33, 6.12]). Thus, the Beijing/W lineage strains may have some special biological features that facilitate the development of extrathoracic tuberculosis.

Population-based study of deletions in five different genomic regions of Mycobacterium tuberculosis and possible clinical relevance of the deletions.

Regions of difference (RDs) have been described in clinical isolates of Mycobacterium tuberculosis, but the potential epidemiological and clinical relevance of the genotypes of these RDs remains to be investigated. We screened a population-based sample of 648 isolates for the deletion of five RDs, designated RD105, RD181, RD142, RD150, and RD239, using microarray-based hybridization, PCR, and DNA sequencing and assessed the associations between the RD deletions and the clinical characteristics of the patients using chi-square analysis and multivariate logistic regression model. Of the 648 isolates, 18 (2.8%) had the RD239 deletion and 39 (6.0%) had the RD105 deletion. The deletions of RD142, RD150, and RD181 subdivided the isolates with the RD105 deletion into four groups comprising a group with concurrent deletions of RD105, RD181, and RD142 (n = 13); a group with concurrent deletions of RD105, RD181, and RD150 (n = 5); a group with concurrent deletions of RD105 and RD181 (n = 13); and a group with a deletion of RD105 only (n = 8). Extrathoracic tuberculosis is statistically significantly associated with infection with the isolates with concurrent deletions of RD105, RD181, and RD142 (adjusted odds ratio [OR] = 3.05; 95% confidence interval [CI] = 1.58, 5.90) and the isolates with concurrent deletions of RD105, RD181, and RD150 (adjusted OR = 11.09; 95% CI = 4.27, 28.80), after controlling for the previously identified risk factors for extrathoracic tuberculosis (human immunodeficiency virus serostatus, race, gender, and the genotype of the plcD gene). These two combinations of RD deletions have the potential for predicting the clinical presentation of M. tuberculosis infection in the human host.

Variable-number tandem repeats that are useful in genotyping isolates of Salmonella enterica subsp. enterica serovars Typhimurium and Newport.

The genome of Salmonella enterica subsp. enterica serovar Typhimurium strain LT2 was analyzed for direct repeats, and 54 sequences containing variable-number tandem repeat loci were identified. Ten primer pairs that anneal upstream and downstream of each selected locus were designed and used to amplify PCR targets in isolates of S. enterica serovars Typhimurium and Newport. Four of the 10 loci did not show polymorphism in the length of products. Six loci were selected for analysis. Isolates of S. enterica serovars Typhimurium and Newport that were related to specific outbreaks and showed identical pulsed-field gel electrophoresis patterns were indistinguishable by the length of the six variable-number tandem repeats. Isolates that differed in their pulsed-field gel electrophoresis patterns showed polymorphism in variable-number tandem repeat profiles. Length of the products was confirmed by DNA sequence analysis. Only 2 of the 10 loci contained exact integers of the direct repeat. Eight loci contained partial copies. The partial copies were maintained at the ends of the variable-number tandem repeat loci in all isolates. In spite of having partial copies that were maintained in all isolates, the number of direct repeats at a locus was polymorphic. Six variable-number tandem repeat loci were useful in distinguishing isolates of S. enterica serovars Typhimurium and Newport that had different pulsed-field gel electrophoresis patterns and in identifying outbreak-associated cases that shared a common pulsed-field gel pattern.

Outbreak of tuberculosis in a homeless population involving multiple sites of transmission.

SETTING: During 2002-2003, a large outbreak of tuberculosis (TB) occurred among persons using multiple homeless facilities in King County, Washington. OBJECTIVE: To control the transmission of TB in multiple settings. DESIGN: In 2002, contacts exposed to patients in homeless facilities were screened using tuberculin skin tests (TSTs) and symptom review. Based on these screening results, sites of transmission were identified and prioritised, and exposed cohorts at these sites were offered intensive screening tests in 2003 (e.g., symptom review, TST, chest radiograph [CXR], sputum examination and culture). Mycobacterium tuberculosis isolates from patients were genotyped using PCR-based methods to identify outbreak-associated patients quickly. RESULTS: During 2002-2003, 48 (15%) of 313 patients diagnosed in King County were outbreak-associated; 47 culture-positive patients had isolates that matched the outbreak strain by genotyping. Three facilities visited by >12 patients in 2002 had a higher prevalence of TST positive results (approximately 30%) among clients compared with the background rate (7%) in the homeless community. Screening contacts with one sputum culture was as sensitive as CXR in detecting TB disease (77% vs. 62%, respectively). CONCLUSIONS: A comprehensive, resource-intensive approach likely helped to control transmission. This outbreak highlights the vulnerability of homeless populations and the need to maintain robust TB programs in urban settings.

[Estimation of vitamin supplements and minerals consumption dispensed through pharmacy offices in the province of Las Palmas]. / Estimación del consumo de suplementos vitamínicos y minerales dispensados a través de las oficinas de farmacia de la provincia de Las Palmas.

BACKGROUND: Vitamin supplements and minerals consumption (SPM) is increasing in occidental societies due to the growing concern about health by the population. OBJECTIVES: To have a initial approaching to the to SPM consumption in the Province of Las Palmas through 2000 and 2001. To identify SPM proportions that are dispensed as pharmaceutical specialities and those who are sold as parapharmacy products. Finally, to describe the evolution of this consumption throughout a year. METHOD: The information was obtained through the list of the whole pharmaceutical specialities and parapharmacy products through 2000 and 2001 who have at least a vitamin in its composition and/or a mineral. RESULTS: Usually, 297 pharmaceutical specialities and 216 parapharmacy products are currently being sold. Pharmaceutical specialities comprised 65.6% of the whole products sold and within them, vitamins were the most dispensed (41.5%). Regarding parapharmacy products, vitamins and minerals compounds were the products more sold (34.6%). Comparing to 2000, during 2001 there was a statistically significant increase in the consumption of parapharmacy products, remaining without changes the use of pharmaceutical specialities. CONCLUSION: On the basis of sold XX SPM consumption seems to be due mainly by pharmaceutical specialities rather than parapharmacy products. Nevertheless through 2001 there was an increase only in the parapharmacy products.

Distribution of insertion- and deletion-associated genetic polymorphisms among four Mycobacterium tuberculosis phospholipase C genes and associations with extrathoracic tuberculosis: a population-based study.

The Mycobacterium tuberculosis genome contains four phospholipase C (PLC)-encoding genes, designated plcA, plcB, plcC, and plcD, respectively. Each of the four genes contributes to the overall PLC activity of M. tuberculosis. PLC is hypothesized to contribute to M. tuberculosis virulence. Infection of M. tuberculosis strains carrying a truncated plcD gene is associated with the occurrence of extrathoracic tuberculosis. However, whether the other three plc genes are also associated with extrathoracic tuberculosis remains to be assessed. We investigated the insertion- and deletion-associated genetic diversity in all four plc genes among 682 epidemiologically and clinically well-characterized M. tuberculosis clinical isolates using PCR, DNA sequencing, and Southern hybridization. Two hundred sixty-six (39%) of the 682 isolates had an interruption in at least one of the four plc genes, most often associated with an IS6110 insertion. The plcD gene interruption was the most common: it was observed in 233 (34%) of the isolates, compared to 4.7%, 4.1%, and 5.9% for plcA, plcB, and plcC gene interruption, respectively. The association between the plc gene genotypes and disease presentation was adjusted for clustering using generalized estimating equations for both bivariate and multivariate analyses. After controlling for the genotypes of the plcABC genes and the host-related risk factors, interruption in the plcD gene remained significantly associated with extrathoracic tuberculosis (odds ratio, 3.27; 95% confidence interval, 1.32 to 8.14). The data suggest that the plcD gene might play a more important role in the pathogenesis of thoracic TB than it does in the pathogenesis of extrathoracic TB.

Epidemiologic import of tuberculosis cases whose isolates have similar but not identical IS6110 restriction fragment length polymorphism patterns.

Isolates of Mycobacterium tuberculosis from patients with epidemiologic links frequently demonstrate identical IS6110 restriction fragment length polymorphism (RFLP) patterns (i.e., RFLP clustering) because they are infected with the same strain. Uncertainty arises with isolates that differ from one another by a few IS6110 hybridizing bands. During the period from 1 January 1996 to 31 December 1999, isolates from 585 tuberculosis (TB) cases were analyzed by RFLP, representing 98.2% of the 596 culture-positive TB cases reported in Arkansas during the study period. Of the 585 cases for which RFLP was available, 419 (71.6%) had an RFLP pattern with more than five copies of IS6110. Of the total 74 clusters, 48 comprised isolates with more than five copies of IS6110 and included 164 cases. Sixty-nine isolates with more than five copies of IS6110 comprising 16 clusters and 60 unique isolates were found to be similar to at least 1 other isolate (differing from it by one or two hybridizing bands). Among the 129 cases whose isolates were similar to other clustered or unique isolates, 16 cases were discovered with epidemiologic links: 14 (15.2%) were among the 92 cases with IS6110 RFLP patterns similar to those in clusters, and 2 (5.2%) were among the 37 unique cases that were similar to another unique case. The isolates from the epidemiologically linked patients shared common spoligotypes; all except one case shared common polymorphic GC-rich sequence (PGRS) patterns. Of the 129 patients whose isolates differed from another by one or two hybridizing IS6110 bands, 101 (78.3%) shared common spoligotypes and 87 (67.4%) shared common PGRS RFLP patterns.

Persistence of a strain of Mycobacterium tuberculosis in a prison system.

SETTING: A prison system with an average year-end census of 9084 inmates. OBJECTIVE: To determine transmission dynamics of tuberculosis over a long period; to establish whether Mycobacterium tuberculosis strains responsible for disease in a prison system persist; and to determine whether patients in a community whose isolates cluster with those in a prison system are linked. DESIGN: Retrospective epidemiologic analysis was performed on tuberculosis cases reported in a prison system over a 9-year period. In addition, IS6110 RFLP patterns of M. tuberculosis isolates obtained from prisoners were compared with those of other cases from the state at large. The results of the RFLP analysis and the epidemiologic investigation were compared. RESULTS: Approximately 80% of tuberculosis cases in the prison system were clustered. Over 9 years, a single strain of M. tuberculosis accounted for more than 50% of cases. Patients from the community at large who were infected with the same strain were linked to the prison system. CONCLUSION: In spite of intensive tuberculosis control efforts, a single strain of M. tuberculosis has persisted in the prison system. Its persistence is accounted for by activation of latent infection in patients who, prior to being diagnosed and treated, infected other patients, who then sustained the transmission chain.

Activated THP-1 cells: an attractive model for the assessment of intracellular growth rates of Mycobacterium tuberculosis isolates.

Capacity of certain Mycobacterium tuberculosis isolates to grow more rapidly in human macrophages may be indicative of increased virulence. Significant differences were observed in intracellular growth of two isolates from sites of tuberculosis transmission, with an outbreak-associated strain growing faster than a strain causing disease in only one person. Activated THP-1 cells are a suitable alternative to peripheral blood monocyte models.

Molecular epidemiology of tuberculosis in Turkey.

Our objective was to determine the extent of fingerprint pattern diversity of Mycobacterium tuberculosis isolates from Turkey. Of the 320 patient isolates, 81 (25.3%) carried

Simultaneous infection with multiple strains of Mycobacterium tuberculosis.

Drug-susceptible and drug-resistant isolates of Mycobacterium tuberculosis were recovered from 2 patients, 1 with isoniazid-resistant tuberculosis (patient 1) and another with multidrug-resistant tuberculosis (patient 2). An investigation included patient interviews, record reviews, and genotyping of isolates. Both patients worked in a medical-waste processing plant. Transmission from waste was responsible for at least the multidrug-resistant infection. We found no evidence that specimens were switched or that cross-contamination of cultures occurred. For patient 1, susceptible and isoniazid-resistant isolates, collected 15 days apart, had 21 and 19 restriction fragments containing IS6110, 18 of which were common to both. For patient 2, a single isolate contained both drug-susceptible and multidrug-resistant colonies, demonstrating 10 and 11 different restriction fragments, respectively. These observations indicate that simultaneous infections with multiple strains of M. tuberculosis occur in immunocompetent hosts and may be responsible for conflicting drug-susceptibility results, though the circumstances of infections in these cases may have been unusual.

The effect of changes in laboratory practices on the rate of false-positive cultures for Mycobacterium tuberculosis.

CONTEXT: False-positive cultures for Mycobacterium tuberculosis have been found in nearly all DNA fingerprinting studies, but the effectiveness of interventions to reduce cross-contamination has not been evaluated. OBJECTIVE: To evaluate whether changes in laboratory policies and procedures reduced the rate of false-positive cultures. DESIGN: Retrospective study of isolates with matching DNA fingerprints. SETTING: A mycobacteriology laboratory serving an urban tuberculosis control program and public hospital system. PATIENTS: All M tuberculosis isolates processed from July 1994 to December 1999. METHODS: Isolates were fingerprinted using IS6110; pTBN12 was used to fingerprint isolates having fewer than 6 copies of IS6110. We further evaluated all patients having only one positive culture whose DNA fingerprint matched that of another isolate processed in the laboratory within 42 days. INTERVENTIONS: We changed laboratory policy to reduce the number of smear-positive specimens processed and changed laboratory procedures to minimize the risk of cross-contamination during batch processing. MAIN OUTCOME MEASURE: The rate of false-positive cultures. RESULTS: Of 13 940 specimens processed during the study period, 630 (4.5%) from 184 patients and 48 laboratory proficiency specimens grew M tuberculosis. There were no cases (0/184) of probable or definite cross-contamination, compared with the 4% rate (8/199) identified in our previous study (P =.008). We also fingerprinted a convenience sample of isolates from other laboratories in Denver; 13.6% (3/22) of these were false-positive, a rate similar to the 11.9% rate (5/42) identified for other laboratories in our previous study (P =.84). CONCLUSIONS: Laboratory cross-contamination decreased significantly after relatively simple, inexpensive changes in laboratory policies and practices. Cross-contamination continued to occur in other laboratories in Denver.

A clinic-based molecular epidemiologic study of tuberculosis in Monterrey, Mexico.

SETTING: A tuberculosis clinic associated with a university hospital in Monterrey, Mexico, an urban community with high tuberculosis incidence. OBJECTIVE: To determine the diversity of DNA fingerprint patterns and the extent of drug resistance of Mycobacterium tuberculosis isolates from patients who attended the clinic. DESIGN: Isolates of M. tuberculosis obtained from 186 patients during the period from 31 January 1996 to 31 March 1998 were tested for susceptibility to isoniazid, rifampicin, ethambutol and streptomycin. Demographic data and the social history of each patient were obtained prospectively by interview. The IS6110 DNA fingerprints were obtained for 166 of the 186 isolates. Secondary typing was carried out on isolates with fewer than six copies of IS6110. RESULTS: Thirty-two per cent of the tested isolates (60/ 186) were drug-resistant, and 18% (33/186) were multidrug-resistant. Approximately 55% of the resistant isolates (33/60) were attributed to acquired resistance. A total of 106 different IS6110 fingerprint patterns were observed among the 166 fingerprinted isolates. Based on both IS6110 and pTBN12 fingerprinting, 65 (39%) of the 166 isolates were part of 22 DNA fingerprint clusters. Various drug susceptibility patterns were seen in most clusters. CONCLUSION: Fingerprint clustering indicates extensive recent transmission of tuberculosis in patients attending the clinic. The prevalence of drug-resistant tuberculosis is high.

Secondary typing of Mycobacterium tuberculosis isolates with matching IS6110 fingerprints from different geographic regions of the United States.

Fifty-nine isolates of Mycobacterium tuberculosis obtained from different states in the United States and representing 25 interstate clusters were investigated. These clusters were identified by computer-assisted analysis of DNA fingerprints submitted during 1996 and 1997 by different laboratories participating in the CDC National Genotyping and Surveillance Network. Isolates were fingerprinted with the IS6110 right-hand probe (IS6110-3'), the IS6110 left-hand probe (IS6110-5'), and the probe pTBN12, containing the polymorphic GC-rich sequence (PGRS). Spoligotyping based on the polymorphism in the 36-bp direct-repeat locus was also performed. As a control, 43 M. tuberculosis isolates in 17 clusters obtained from patients in Arkansas during the study period were analyzed. Of the 25 interstate clusters, 19 were confirmed as correctly clustered when all the isolates were analyzed on the same gel using the IS6110-3' probe. Of the 19 true IS6110-3' clusters, 10 (53%) were subdivided by one or more secondary typing methods. Clustering of the control group was virtually identical by all methods. Of the three different secondary typing methods, spoligotyping was the least discriminating. IS6110-5' fingerprinting was as discriminating as PGRS fingerprinting. The data indicate that the IS6110-5' probe not only is a useful secondary typing method but also probably would prove to be a more useful primary typing method for a genotyping network which involves isolates from different geographic regions.

Efficacy of an unsupervised 8-month rifampicin-containing regimen for the treatment of pulmonary tuberculosis in HIV-infected adults. Uganda-Case Western Reserve University Research Collaboration.

SETTING: National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda. OBJECTIVE: To assess the efficacy of a daily, self-administered 8-month rifampicin-containing regimen for the treatment of pulmonary tuberculosis (TB) in human immunodeficiency virus (HIV) infected adults. DESIGN: Treatment outcomes in patients with pulmonary TB treated with a single 8-month regimen and followed in a prospective epidemiological study. RESULTS: Two hundred and sixty-five HIV-infected and 26 non-HIV-infected adults with initial episodes of pulmonary tuberculosis were treated with 2 months of daily isoniazid (INH), rifampicin (RMP), ethambutol and pyrazinamide followed by 6 months of daily INH + RMP. Median follow-up was 17.8 months. Ninety-five per cent of the HIV-infected and all of the non-HIV-infected patients who had sputum examined were sputum culture negative after 2 months of treatment. Twenty-two HIV-infected and no non-HIV-infected patients died during treatment. Relapse rates were 8.4% (5.9 per 100 person-years of observation [PYO], 95%CI 3.2-8.6) among HIV-infected patients and 4.5% (2.1/100 PYO, 95%CI 0-7.8) for non-HIV-infected patients. Adverse drug reactions occurred in 37% of the HIV-infected patients; most were minor and self-limiting. CONCLUSION: An 8-month RMP-containing regimen was well tolerated and effective in the treatment of HIV-infected adults with initial episodes of pulmonary TB. Relapse rates were similar to those reported with 6-month short-course regimens in HIV-infected individuals. Decisions about the duration of anti-tuberculosis treatment for HIV-infected adults must balance programme resources and the likelihood of poor compliance with longer regimens with the potential for a modest decrease in relapses with longer treatment.

Spoligotyping and polymorphic GC-rich repetitive sequence fingerprinting of mycobacterium tuberculosis strains having few copies of IS6110.

Several genetic loci have been utilized to genotype isolates of Mycobacterium tuberculosis. A shortcoming of the most commonly used method, IS6110 fingerprinting, is that it does not adequately discriminate between isolates having few copies of IS6110. This study was undertaken to compare pTBN12 fingerprinting of polymorphic GC-rich repetitive sequence genes and spoligotyping of the direct repeat locus as secondary typing procedures for M. tuberculosis isolates having fewer than six copies of IS6110. A total of 88 isolates (100% of the isolates with fewer than six copies of IS6110 isolated in Arkansas during 1996 and 1997) were included in this study. Among the 88 isolates, 34 different IS6110 patterns were observed, 10 of which were shared by more than 1 isolate, involving a total of 64 isolates. The 64 isolates were subdivided into 13 clusters (containing 37 isolates) and 27 unique isolates based on a combination of IS6110 and pTBN12 fingerprinting and into 11 clusters (containing 51 isolates) and 13 unique isolates based on a combination of IS6110 fingerprinting and spoligotyping. Identical spoligotypes were found among isolates having different IS6110 patterns, as well as among isolates showing different pTBN12 patterns. In contrast, all isolates that had different IS6110 patterns were found to be unique by pTBN12 typing. The clustering rate was 73, 58, and 42%, respectively, for IS6110 fingerprinting alone, IS6110 fingerprinting and spoligotyping combined, and IS6110 and pTBN12 combined fingerprinting. The data indicate that the pTBN12 method has greater discriminating power among low-copy-number isolates than does spoligotyping.

Mapping of IS6110 insertion sites in two epidemic strains of Mycobacterium tuberculosis.

A widely distributed strain designated 210 was identified in a study of the diversity of Mycobacterium tuberculosis DNA fingerprints from three geographically separate states in the United States. This strain is characterized by a 21-band fingerprint pattern when probed with IS6110, and the pattern is similar to that displayed by strains designated W. Intracellular growth of strain 210 isolates in human macrophages is significantly faster than that of isolates from other clusters or nonclustered isolates. The purpose of this study was to identify the sites of IS6110 insertions in strain 210 and compare these to IS6110 insertion sites in strain W. Our hypothesis is that an IS6110 insertion site(s) could possibly be responsible for a strain's increased capacity for transmission and/or replication. In this report, the insertion sites in strains 210 and W are described and referenced to their location in the M. tuberculosis H37Rv genome sequence. The W and 210 strains have 17 identical sites of IS6110 insertion and additional sequence not found in H37Rv but present in other clinical isolates. The IS6110 insertion site in the 36-bp direct repeat (DR) region of strains 210 and W has 15 spacers in the left flanking region. The DR region on the right side of IS6110 has been deleted. Five sites of insertion in strain 210 not found in strain W are described, as well as two unique sites in strain W. One copy of IS6110 was found to reside 55 bp in the ctpD gene. This gene is expressed, indicating that IS6110 can provide a promoter sequence for the transcription of genes.

Nosocomial transmission of Mycobacterium bovis bacille Calmette-Guerin to children receiving cancer therapy and to their health care providers.

A previous report of nosocomial infection due to Mycobacterium bovis bacille Calmette-Guerin (BCG) implicated contamination of chemotherapy solutions reconstituted under the same biosafety hood as BCG vaccine used for bladder cancer therapy. We report 3 similar BCG infections in children and describe evidence of respiratory transmission to health care workers (HCWs) from 1 patient. These children were receiving chemotherapy for leukemia when they presented with active tuberculosis. Each isolate was identified biochemically and by both gas-liquid chromatography and major polymorphic tandem repeat-polymerase chain reaction. Pulsed-field gel electrophoresis showed that 2 isolates were identical strains and identical to the Tice and Connaught strains licensed in the United States for bladder chemotherapy. The third isolate differed by a single fragment after DraI restriction. One patient with heavily positive sputum exposed numerous HCWs. Of 41 HCWs, 2 (5%) converted their purified protein derivatives (PPD) skin test. These data underscore the risk of nosocomial BCG transmission by contamination of chemotherapy solutions and demonstrate the potential for transmission to HCWs from patients with active pulmonary disease.