Sustained effect of isoniazid preventive therapy among household contacts in Brazil

BACKGROUND: Isoniazid preventive therapy (IPT) is highly effective in preventing TB disease; however, its long-term benefit in household contacts (HHCs) of infectious TB cases is unclear.METHODS: We conducted a retrospective analysis of two household contact studies in Vitoria, ES, Brazil, between 2008 and 2015. Households with smear-positive, culture-proven TB disease were enrolled. Eligible HHCs with tuberculin skin test (TST) indurations of ≥10 mm were referred to local TB clinics and IPT was started according to national guidelines. We reviewed the national dataset information system in January 2020 to identify HHCs with a diagnosis of TB disease. Time to event and Cox proportional regression analysis were conducted to identify factors associated with TB disease.RESULTS: Of the 1097 HHCs enrolled, 654 (60%) had TST ≥10 mm; 160 (24%) initiated IPT, of whom 115 (71.9%) completed IPT, which accounts for an overall completion rate of 18% among the population at risk; 42 (6%) TB cases were identified. IPT was associated with a 71% decrease in TB disease rates (HR 0.29, 95% CI 0.10-0.82; P = 0.02) among HHCs with TST ≥10 mm. IPT effect was sustained, as TB cases in HHCs without IPT occurred along the 7.9-year follow-up, whereas all four TB cases in HHCs with IPT were diagnosed within the first 3 years after exposureCONCLUSION: Isoniazid provides long-term protection for TB disease in household contacts of culture-proven TB cases.

Toll-like receptors blocking restores in vitro microbicidal activity in latent tuberculosis-infected subjects

BACKGROUND

Latent tuberculous infection (LTBI) can function as a 'reservoir' for Mycobacterium tuberculosis. Given that T-regulatory cell (T_reg) numbers are augmented in LTBI, it is likely that Toll-like receptors (TLRs) may have a role in T_reg function. Elucidation of the immune mechanisms associated with tuberculosis (TB) development may help to control M. tuberculosis spread.OBJECTIVE: To investigate the role of TLR2, TLR4 and TLR9 in hindered in vitro microbicidal activity and increase T_reg number during LTBI.

DESIGN

Whole blood cell cultures from individuals with LTBI and healthy controls (HCs) infected with live M. tuberculosis H37Rv strain were used to investigate the effect of TLR2, TLR4 and TLR9 on T_reg number, microbicidal activity, and interferon-gamma and interleukin (IL)10 production.

RESULTS

LTBI subjects were characterised by increased T_reg number and impaired microbicidal activity when compared with HCs. Specific blockade of TLR4 and TLR9 led to a significant reduction in T_reg number, a decrease in IL-10 production and substantial upregulation of microbicidal activity.

CONCLUSION

M. tuberculosis infection may activate TLR4 and TLR9 pathways to suppress M. tuberculosis-specific immune responses. Here, we show that activation of TLR4 and TLR9 hinder microbicidal activity during LTBI.

Contribution of the Ogawa-Kudoh swab culture method to the diagnosis of pulmonary tuberculosis in Brazil

OBJECTIVE

To analyse the contribution of the Ogawa-Kudoh (O-K) swab culture method to the diagnosis of pulmonary tuberculosis (PTB) in four different regions of Brazil.

DESIGN

This study was carried out in two phases. Phase 1 was designed to compare the direct swab culture method (O-K) with the culture concentrated method (N-acetyl-L-cysteine-sodium hydroxide [NALC-NaOH]); for this purpose, 569 sputum samples were cultured by both methods. Phase 2 was carried out to assess the contribution of the O-K method to the diagnosis of PTB in four different regions in Brazil, based on the evaluation of 19,163 sputum samples.

RESULTS

In the first phase of the study, O-K culture had a sensitivity of 94.8% and specificity of 99.8% in cases confirmed by NALC-NaOH/Löwenstein-Jensen (LJ) culture. In the second phase of the study, the overall contribution of O-K culture compared to acid-fast bacilli (AFB) examination (AFB-/culture+) to the diagnosis of PTB was 29.8%.

CONCLUSION

O-K culture contributes significantly to the diagnosis of smear-negative PTB. Importantly, this method allows the recovery of clinical isolates in areas where use of the standard culture centrifuge is impossible, indicating that the O-K swab culture method should become a standard method for TB diagnosis in these regions.

Smoking and 2-month culture conversion during anti-tuberculosis treatment

OBJECTIVE

To investigate risk factors for delayed sputum culture conversion to negative during anti-tuberculosis treatment, with an emphasis on smoking.

DESIGN

Nested case-control study of adults with non-cavitary, culture-confirmed pulmonary tuberculosis (TB) participating in an anti-tuberculosis treatment trial in Brazil. A case of delayed culture conversion was a patient who remained culture-positive after 2 months of treatment. Odds ratios with 95% confidence intervals were calculated.

RESULTS

Fifty-three cases and 240 control patients were analyzed. Smokers had three-fold greater odds of remaining culture-positive after 2 months of treatment (P = 0.007) than non-smokers, while smokers and ex-smokers who smoked >20 cigarettes a day had two-fold greater odds of remaining culture-positive after 2 months of treatment (P = 0.045).

CONCLUSION

Cigarette smoking adversely affects culture conversion during anti-tuberculosis treatment. Support for smoking cessation should be considered to improve outcomes in TB control programs.

Reduction of contamination of mycobacterial growth indicator tubes using increased PANTA concentration

We assessed the effect of a double concentration of supplemental polymyxin B, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) added to the Mycobacterial Growth Indicator Tube (MGIT) on contamination and positivity rates in 216 sputum cultures. Contamination rates were respectively 12.9% and 5.5% for samples processed using standard and double PANTA concentrations (P = 0.0001, McNemar's test). Thirty-five per cent of cultures performed using standard PANTA and 36.5% of those performed using two-fold PANTA concentrations were positive for Mycobacterium tuberculosis, compared to 25.9% of cultures inoculated on Ogawa medium. These results suggest that the use of MGIT with 2× PANTA may be useful in reducing culture contamination without reducing the diagnostic yield.

Delay in diagnosis of pulmonary tuberculosis at a primary health clinic in Vitoria, Brazil

SETTING

Primary health clinics in Vitoria, Espirito Santo, Brazil.

OBJECTIVE

To identify risk factors associated with patient and health care delays among patients seeking care at primary health clinics.

METHODS

A prospective study among tuberculosis (TB) patients diagnosed in Vitoria between 1 January 2003 and 30 December 2007. A questionnaire ascertained the date of onset and duration of TB symptoms and medical records were reviewed. Between-group distributions of delay were compared and multivariate logistic regression was performed.

RESULTS

Of 304 patients, 296 (97%) reported at least one TB symptom presenting for the first time to a qualified health service; 244 (80%) reported cough > 3 weeks. Median health care delay was 30 days (range 5-68), and median total delay was 110 days (range 26-784). Multivariate analysis revealed any cough (OR(adj) 7.35, 95%CI 2.40-22.5) and weight at TB diagnosis < 60 kg (OR(adj) 5.92, 95%CI 1.83-19.1) to be associated with patient delay of ≥ 30 days. Factors increasing risk of prolonged delay (≥ 90 days) were age ≥ 30 years (OR(adj) 1.93, 95%CI 1.09-3.43) and chest pain (OR(adj) 2.42, 95%CI 1.29-4.53).

CONCLUSION

Improving health care workers' education regarding TB symptoms and implementing active case finding in targeted populations may reduce delays.

Spatial patterns of pulmonary tuberculosis incidence and their relationship to socio-economic status in Vitoria, Brazil

OBJECTIVE

To investigate spatial patterns of the incidence of pulmonary tuberculosis (TB) and its relationship with socio-economic status in Vitoria, Espirito Santo, Brazil.

DESIGN

In a 4-year, retrospective, territory-based surveillance study of all new pulmonary TB cases conducted in Vitoria between 2002 and 2006, spatial patterns of disease incidence were compared using spatial clustering statistics (Anselin's local indicators of spatial association [LISA] and Getis-Ord Gi* statistics), smoothed empirical Bayes estimates and model-predicted incidence rates. Spatial Poisson models were fit to examine the relationship between socio-economic status and TB incidence.

RESULTS

A total of 651 TB cases were reported across 78 neighborhoods, with rates ranging from 0 to 129 cases per 100,000 population. Moran's I indicated strong spatial autocorrelation among incidence rates (0.399, P < 0.0001), and four areas of high incidence were identified by LISA and Gi* statistics. Smoothed spatial empirical Bayes estimates demonstrate that two of these areas range from 70 to 90 cases/100,000, while the other two range from 40 to 70 cases/100,000. TB incidence and socio-economic status had a significant curvilinear relationship (P = 0.02).

CONCLUSIONS

Data derived from these spatial statistical tools will help TB control programs to allocate TB resources to those populations most at risk of increasing TB rates and to target areas where TB control efforts need to be concentrated.

Comparison of two concentrations of NALC-NaOH for decontamination of sputum for mycobacterial culture

This study compared the effect of using two different concentrations of sodium hydroxide (NaOH) in the N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) method for sputum decontamination on smear and culture positivity and the proportion of contaminated cultures: 14% of cultures were contaminated using the standard final 1% NaOH concentration during processing compared to 11% contaminated cultures using a final 1.25% NaOH concentration (P < 0.008). The proportion of cultures positive for mycobacteria decreased from 21% to 11% for sputum processed with 1% and 1.25% final NaOH concentrations, respectively (P < 0.001). Our findings suggest that a small reduction in culture contamination did not justify the considerable loss of positive cultures.

Multicentre evaluation of an automated BACTEC 960 system for susceptibility testing of Mycobacterium tuberculosis

SETTING

Three mycobacteria reference laboratories in the south-eastern part of Brazil.

OBJECTIVE

To evaluate the automated Mycobacteria Growth Indicator Tube (MGIT) for drug susceptibility testing of Mycobacterium tuberculosis.

DESIGN

Performance of the automated BACTEC MGIT 960 (M960) system for testing M. tuberculosis susceptibility to streptomycin (SM), isoniazid (INH), rifampicin (RMP) and ethambutol (EMB) was evaluated with 95 clinical isolates and compared to the results of the radiometric BACTEC 460TB (B460) system, the proportion method (PM), and the resistance ratio method (RRM). Judicial susceptibility profiles of 88 isolates were defined based on two or more concordant results among B460, PM and RRM, and used as a reference for comparison with M960 results.

RESULTS

Agreement rates between M960 and conventional methods were 95.2% with B460, 96.6% with the PM and 93.4% with the RRM. The lowest agreement rates were obtained for SM with the RRM and for EMB with B460. When comparing M960 with judicial susceptibility profiles, the agreement rate was 97.9%. The agreement rates obtained for INH and RMP were 99.2% and for SM and EMB they were 96.2% and 96.9%, respectively. The mean time to reporting the M960 results was 6.9 days.

CONCLUSION

M960 offers great improvements when compared to the proportion and resistance ratio methods and would benefit patient treatment.

Early and extended early bactericidal activity of levofloxacin, gatifloxacin and moxifloxacin in pulmonary tuberculosis

OBJECTIVE

To evaluate the early bactericidal activity (EBA) of the new fluoroquinolones levofloxacin, gatifloxacin and moxifloxacin in patients with pulmonary tuberculosis (PTB).

DESIGN

Randomized, open-label trial. Forty adults with newly diagnosed smear-positive PTB (10 per arm) were assigned to receive isoniazid (INH) 300 mg, levofloxacin 1000 mg, gatifloxacin 400 mg, or moxifloxacin 400 mg daily for 7 days. Sputum for quantitative culture was collected for 2 days before and daily during 7 days of monotherapy. Bactericidal activity was estimated by measuring the decline in bacilli during the first 2 days (EBA 0-2) and last 5 days of monotherapy (extended EBA, EBA 2-7). Laboratory staff were blinded to treatment assignment.

RESULTS

The EBA 0-2 of INH (0.67 log10 cfu/ml/day) was greater than that of moxifloxacin and gatifloxacin (0.33 and 0.35 log10 cfu/ml/day, respectively), but not of levofloxacin 1000 mg daily (0.45 log10 cfu/ml/day) (P = 0.14). Bactericidal activity between days 2 and 7 was similar for all three fluoroquinolones. In a pooled comparison, the EBA 2-7 of the fluoroquinolones was greater than for INH.

CONCLUSION

Moxifloxacin, gatifloxacin, and high-dose levofloxacin have excellent EBA, only slightly less than for INH, and greater extended EBA. These drugs warrant further study in the treatment of drug-susceptible TB.

Mycobacteraemia among HIV-1-infected patients in São Paulo, Brazil: 1995 to 1998

From July 1995 to August 1998, mycobacterial blood cultures were obtained from 1032 HIV-infected patients seen at the Centro de Referência e Treinamento de AIDS (CRTA), Hospital São Paulo (HSP), and Centro de Referência de AIDS de Santos (CRAS). Overall, 179 episodes of mycobacteraemia were detected: 111 (62.0%) at CRTA, 50 (27.9%) at HSP, and 18 (10.1%) at CRAS. The frequency of positive cultures declined sharply from 22.6% in 1995 to 6.9% in 1998, consistent with the decrease in opportunistic infections following the publicly funded distribution of highly active antiretroviral therapy. In 1995, mycobacteraemia was more frequently due to Mycobacterium avium complex (59.2%) than Mycobacterium tuberculosis (28.6%), whereas in 1998 the relative frequencies were reversed (28.6 vs. 64.3% respectively), probably justified by the increased virulence of M. tuberculosis and the greater risk of invasive infection in less-immunocompromised patients, including patients unaware they are infected with HIV.

Tuberculosis and drug resistance among patients seen at an AIDS Reference Center in São Paulo, Brazil

OBJECTIVES

To assess the frequency of resistance of Mycobacterium tuberculosis to antituberculosis drugs and the factors associated with it among patients with tuberculosis (TB) and acquired immunodeficiency syndrome (AIDS).

MATERIALS AND METHODS

The medical records of TB and AIDS cases diagnosed from 1992 to 1997 in a public service for AIDS care were reviewed.

RESULTS

Resistance was diagnosed in 82 (19%) of 431 cases. The mean and median values between the diagnosis of AIDS and the diagnosis of TB were 214.8 days and 70.5 days, respectively. Multidrug-resistant TB (MDR TB) occurred in 11.3% of cases. Of the 186 patients with no previous treatment, 13 (6.9%) presented primary MDR TB. Of the 90 cases with previous treatment, six (6.7%) presented monoresistance to rifampin and 27 (30%) presented MDR TB. The distribution of cases with sensitive and resistant M. tuberculosis strains was homogeneous in terms of the following variables: gender, age, category of exposure to human immunodeficiency virus (HIV), alcoholism, and homelessness. Multivariate analysis showed an association between resistance and the two following variables: previous treatment and duration of AIDS prior to TB exceeding 71 days. The rates of primary multiresistance and of monoresistance to rifampin were higher than those detected in HIV-negative patients in Brazil.

CONCLUSIONS

In this patient series, M. tuberculosis resistance was predominantly of the acquired type, and resistance was independently associated with previous treatment for TB and with duration of AIDS prior to TB exceeding 71 days.

Safety and bactericidal activity of rifalazil in patients with pulmonary tuberculosis

Rifalazil, also known as KRM-1648 or benzoxazinorifamycin, is a new semisynthetic rifamycin with a long half-life of approximately 60 h. Rifalazil has potent bactericidal activity against Mycobacterium tuberculosis in vitro and in animal models of tuberculosis (TB). Prior studies in healthy volunteers showed that once-weekly doses of 25 to 50 mg of rifalazil were well tolerated. In this randomized, open-label, active-controlled phase II clinical trial, 65 subjects with sputum smear-positive pulmonary TB received one of the following regimens for the first 2 weeks of therapy: 16 subjects received isoniazid (INH) (5 mg/kg of body weight) daily; 16 received INH (5 mg/kg) and rifampin (10 mg/kg) daily; 17 received INH (5 mg/kg) daily plus 10 mg of rifalazil once weekly; and 16 received INH (5 mg/kg) daily and 25 mg of rifalazil once weekly. All subjects were then put on 6 months of standard TB therapy. Pretreatment and day 15 sputum CFU of M. tuberculosis were measured to assess the bactericidal activity of each regimen. The number of drug-related adverse experiences was low and not significantly different among treatment arms. A transient decrease in absolute neutrophil count to less than 2,000 cells/mm(3) was detected in 10 to 20% of patients in the rifalazil- and rifampin-containing treatment arms without clinical consequences. Decreases in CFU counts were comparable among the four treatment arms; however, the CFU results were statistically inconclusive due to the variability in the control arms. Acquired drug resistance did not occur in any patient. Studies focused on determining a maximum tolerated dose will help elucidate the full anti-TB effect of rifalazil.

A whole blood bactericidal assay for tuberculosis

The bactericidal activity of orally administered antituberculosis (anti-TB) drugs was determined in a whole blood culture model of intracellular infection in which microbial killing reflects the combined effects of drug and immune mechanisms. Rifampin (Rif) was the most active compound studied and reduced the number of viable bacilli by >4 logs. Isoniazid (INH), 2 quinolones, and pyrazinamide (PZA) showed intermediate levels of activity. Ethambutol exerted only a bacteristatic effect; amoxicillin/clavulanate was inactive. The combination of INH-Rif-PZA showed strong activity against 11 drug-sensitive isolates (mean, -3.8 log) but no activity against 12 multidrug-resistant (MDR) strains. The combination of levofloxacin-PZA-ethambutol had intermediate bactericidal activity against MDR isolates (mean, -1.2 log) but failed to equal that of INH-Rif-PZA against sensitive isolates (P<.001). The whole blood BACTEC method (Becton Dickinson) may be useful for the early clinical evaluation of new anti-TB drugs and in the management of individual patients.

Infection and disease among household contacts of patients with multidrug-resistant tuberculosis

SETTING

Urban public teaching and referral hospital in Espirito Santo, Brazil.

OBJECTIVE

To assess whether rates of infection and progression to active tuberculosis (TB) differed between household contacts of patients with multidrug-resistant (MDR) and drug susceptible (DS) pulmonary tuberculosis.

DESIGN

Household contacts were assessed for evidence of TB infection and disease by purified protein derivative (PPD) skin testing, physical examination, chest X-ray, and sputum smear and culture.

RESULTS

Among 133 close contacts of patients with MDR-TB, 44% were PPD-positive (> or =10 mm) compared to 37% of 231 contacts of the DS-TB cases (P = 0.18, chi2 test, OR 1.2, 95%CI 0.8-2). In a multivariate logistic regression analysis, after allowance for between-household variation in PPD responses, PPD positivity among household contacts of patients with MDR-TB remained comparable to PPD positivity in contacts of patients with DS-TB (OR 2.1, 95%CI 0.7-6.5). Respectively six (4%) and 11 (4%) contacts of the MDR- and DS-TB cases were found to have active TB at the time of initial evaluation or during follow-up (P = 0.78, chi2 test). Five of six contacts of MDR-TB cases and nine of nine contacts of DS-TB cases who developed TB, and for whom drug susceptibility test results were available, had the same bacterial susceptibility profiles as their index cases. DNA fingerprinting analysis of Mycobacterium tuberculosis isolates was identical between household contacts with active TB and the index MDR or DS-TB case for all 14 pairs compared.

CONCLUSION

Our data suggest that the prevalence of tuberculous infection and progression to active TB among household contacts exposed to DS and MDR-TB cases is comparable, despite a longer duration of exposure of contacts to the index case in patients with MDR-TB.

Inhibition of isoniazid-induced expression of Mycobacterium tuberculosis antigen 85 in sputum: potential surrogate marker in tuberculosis chemotherapy trials

Mycobacterium tuberculosis antigen 85 is induced in vitro by isoniazid (INH); its sustained induction in sputum during tuberculosis (TB) therapy predicts relapse. In this trial, rifampin or rifalazil inhibited the induction of sputum antigen 85 by INH in a dose-dependent fashion. This approach may facilitate the evaluation of new TB drugs.

IS1245 genotypic analysis of Mycobacterium avium isolates from patients in Brazil

OBJECTIVE

Disseminated Mycobacterium avium infection is an emerging opportunistic disease among patients with acquired immunodeficiency syndrome (AIDS) in Brazil. The mode of transmission of M. avium in a developing country setting needs to be better characterized.

METHODS

Mycobacterium avium strain collections in São Paulo and Rio de Janeiro were analyzed according to the strains' IS1245 DNA gel electrophoretic migration patterns. Medical records of the patients from whom M. avium isolates were available were reviewed, and their demographic characteristics were stratified according to the isolates' IS1245 DNA fingerprint patterns.

RESULTS

Of 105 patients, 33 (31%) with M. avium isolated between 1990 and 1994 had strains having IS1245 patterns identical in patterns seen in isolates from two or more patients (designated as cluster pattern strains). Cluster pattern strains were isolated from 21 (39%) of 54 patients with disseminated infection (defined as infection due to M. avium isolated from a sterile site in an adult patient). Six of the cluster pattern strains were isolated only from sterile sites. In São Paulo, cluster pattern strains were significantly more likely to be isolated from patients with disseminated disease.

CONCLUSIONS

These preliminary observations suggest that in large cities of Brazil, a high proportion (at least 39%) of disseminated M. avium infections in patients with AIDS results from a recent transmission. Some strains of M. avium may be more likely to cause disseminated disease than others after an infection.

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.

Molecular epidemiology of Mycobacterium avium complex isolated from patients with and without AIDS in Brazil and England

Mycobacterium avium complex (MAC) is ubiquitous throughout the world. It is an opportunistic pathogen in AIDS patients but the number of cases in HIV negative patients is also increasing. The aim of this study was to determine whether patients were being infected with different MAC strains or whether one strain was dominant. DNA obtained from isolates in Brazil and England were compared using pulsed field gel electrophoresis (PFGE). Strains from 22 Brazilian patients clustered into 7 groups but 68/90 patients had a unique strain. In all patients, Brazilian and English, the same strain was isolated repeatedly over time, some over several years. This study shows that it is most likely that Man is infected from the environment and that one strain can survive without change for many years both in the environment and in Man.

Analysis of Mycobacterium avium complex serovars isolated from AIDS patients from southeast Brazil

The purpose of this study was to assess the distribution of Mycobacterium avium serovars isolated from AIDS patients in São Paulo and Rio de Janeiro. Ninety single site or multiple site isolates from 75 patients were examined. The most frequent serovars found were 8 (39.2%), 4 (21.4%) and 1 (10.7%). The frequency of mixed infections with serovar 8 or 4 was 37.8%. Among the 90 strains examined, M. intracellulare serovars (7 strains) and M. scrofulaceum (4 strains) were found in 11 isolates (12%) indicating that M. avium (88%) was the major opportunistic species in the M. avium complex isolates in Brazilian AIDS patients.

Tuberculosis and HIV infection among female inmates in São Paulo, Brazil: a prospective cohort study

Prison populations are at increased risk of both human immunodeficiency virus (HIV) and Mycobacterium tuberculosis infections, but among female inmates information on such risks remains scarce, especially in developing countries. Between October 1992 and November 1993, 350 women incarcerated at a prison in São Paulo, Brazil, were prospectively evaluated for HIV and M. tuberculosis infection and disease. Among them, 87 (25%) were HIV seropositive, and 20 (5.7%) had tuberculosis (TB). During the incarceration period, the purified protein derivative test conversion rate was 29% for HIV-positive and 32% for HIV-negative women. However, the incidence of TB was 9.9 per 100 person-years for HIV-positive and 0.7 per 100 person-years of incarceration for HIV-negative women (p < 0.0001). A multivariate analysis indicated that HIV infection (p < 0.0001) and incarceration time < 12 months (p < 0.05) were each associated with TB. These findings indicate that new transmissions of M. tuberculosis infection are common among female inmates and that HIV-infected women are more likely to acquire active disease during the first 12 months of incarceration. Because of their role in childbearing and care female inmates are an important potential source of transmission of M. tuberculosis, and new strategies to control the spread of TB in prisons need to be developed.

Evaluation of mycobacteria growth indicator tube for recovery and drug susceptibility testing of Mycobacterium tuberculosis isolates from respiratory specimens

The new BBL mycobacteria growth indicator tube (MGIT) was evaluated for its ability to detect mycobacteria directly from patient specimens and to determine the drug susceptibility of Mycobacterium tuberculosis isolates. A total of 85 respiratory specimens were tested. Specimens were digested, concentrated, examined microscopically for acid-fast bacilli, and inoculated into MGITs and onto Lowenstein-Jensen slants by standard procedures. The tubes were incubated at 37 degrees C and were examined daily for fluorescence to 365-nm UV light. All 25 specimens smear positive for acid-fast bacilli were tested for drug susceptibility in MGITs containing 1.0 mu g of rifampin per ml, 0.1 mu g of isoniazid per ml, 2.0 mu g of streptomycin per ml, and 2.0 mu g of ofloxacin per ml. These results were compared with those obtained by testing the same M. tuberculosis isolates by the indirect proportion method at drug concentrations of 4.0 mu g of rifampin per ml, 0.2 mu g of isoniazid per ml, 2.0 mu g of ethambutol per ml. 4.0 mu g of streptomycin per ml, and 2.0 mu g of ofloxacin per ml. No significant difference in the sensitivity of detection of M. tuberculosis isolates was found between the two methods. However, the time to detection was significantly shorter in MGITs. Drug susceptibility test results for M. tuberculosis isolates by the two methods demonstrated an excellent correlation. The mean time to reporting of drug susceptibility results was 5 days for MGITs versus 16 days for Lowenstein-Jensen slants. The results of this preliminary study indicate that the MGIT system appears to have potential for routine use in mycobacteriology for both the detection and the drug susceptibility testing of M. tuberculosis isolates. However, it is important to emphasize that simple nonautomated equipment should be developed to improve the accuracy of fluorescence detection.

Drug resistance of M. tuberculosis isolated from patients with HIV infection seen at an AIDS Reference Center in São Paulo, Brazil

M. tuberculosis-positive cultures were obtained from 228 patients seen in our service and drug sensitivity assays were carried out from January 1992 to December 1994. A survey of the medical records of these patients showed resistance to one or more drugs in 47 (20.6%), 25 of whom (10.9%), who reported previous treatment, were considered to have acquired resistance. Among the antecedents investigated, only previous treatment and alcoholism were the factors independently associated with the occurrence of resistance. The survival of patients with resistant strains was lower than that of patients attacked by non-resistant M. tuberculosis. We conclude that in the present series M. tuberculosis resistance to tuberculostatic agents was predominantly of the acquired type.

Mycobacterium avium complex (MAC) isolated from AIDS patients and the criteria required for its implication in disease

Before the AIDS pandemia, the Mycobacterium avium complex (MAC) was responsible in most cases for the pneumopathies that attack patients with basic chronic pulmonary diseases such as emphysema and chronic bronchitis. In 1981, with the advent of the acquired immunodeficiency syndrome (AIDS), MAC started to represent one of the most frequent bacterial diseases among AIDS patients, with the disseminated form of the disease being the major clinical manifestation of the infection. Between January 1989 and February 1991, the Section of Mycobacteria of the Adolfo Lutz Institute, São Paulo, isolated MAC from 103 patients by culturing different sterile and no-sterile processed specimens collected from 2304 patients seen at the AIDS Reference and Training Center and/or Emilio Ribas Infectology Institute. Disseminated disease was diagnosed in 29 of those patients on the basis of MAC isolation from blood and/or bone marrow aspirate. The other 74 patients were divided into categories highly (5), moderately (26) and little suggestive of disease (43) according to the criteria of DAVIDSON (1989). The various criteria for MAC isolation from sterile and non-sterile specimens are discussed.

Mycobacterium avium complex (MAC): an unusual potential pathogen in cerebrospinal fluid of AIDS patients

Mycobacterium avium complex (MAC) is frequently isolated from patients with late complications of Acquired Immunodeficiency Syndrome (AIDS), especially in North America and Europe. However, its isolation from the central nervous system (CNS) has been seldom reported in these countries. MAC infections in AIDS patients in African and Latin American countries are believed to be uncommon. We report the isolation of MAC from cerebrospinal fluid (CSF) of 11 AIDS patients out of 1723 (0.63%) seen at "Centro de Referência e Treinamento-AIDS", São Paulo and discuss the significance of its isolation.

Catalase expression, katG, and MIC of isoniazid for Mycobacterium tuberculosis isolates from São Paulo, Brazil

The MIC of isoniazid, peroxidase-catalase expression, and the presence of the katG gene for 102 Mycobacterium tuberculosis isolates from patients in São Paulo were compared. Fifty-three isoniazid-resistant and 49 isoniazid-sensitive isolates were analyzed by polymerase chain reaction (PCR) for the presence of katG sequences. All isoniazid-sensitive and 43 (81%) isoniazid-resistant isolates expressed catalase (P = .001). None of isoniazid-sensitive and 4 (7%) of 53 isoniazid-resistant isolates lacked katG sequences. Among 6 isolates with MICs > 50 micrograms/mL, 5 (83%) did not express catalase and 2 lacked katG sequences; only 1 had complete gene deletion shown by Southern blot analysis. These findings indicate a correlation between loss of catalase and isoniazid resistance among highly resistant isolates, but these isolates were a small proportion of resistant clinical M. tuberculosis isolates from São Paulo.

Bacterial agents isolated from cerebrospinal fluid of patients with acquired immunodeficiency syndrome (AIDS) and neurological complications

Cerebrospinal fluid (CSF) samples from 2083 patients with acquired immunodeficiency syndrome (AIDS) and neurological complications were bacteriologically examined during a period of 7 years (1984-1990). The percentage of patients who had at least one bacterial agent cultured from the CSF was 6.2%. Mycobacterium tuberculosis was the most frequently isolated agent (4.3%), followed by Mycobacterium avium complex or MAC (0.7%), Pseudomonas spp (0.5%), Enterobacter spp (0.4%), and Staphylococcus aureus (0.3%). Among 130 culture positive patients, 89 (68.5%) had M. tuberculosis and 15 (11.6%) had MAC. The frequency of bacterial isolations increased from 1988 (5.2%) to 1990 (7.2%), partly due to the increase in MAC isolations. Bacterial agents were more frequently isolated from patients in the age group 21-30 years and from women (p < 0.05).

Isolation of Mycobacterium avium complex from bone marrow aspirates of AIDS patients in Brazil

Mycobacterium avium complex (MAC) infection has not been reported as a major opportunistic infection among patients with AIDS in Latin America or Africa. In this study, 125 AIDS patients who had persistent fever, anemia, and leukopenia were examined among 2628 AIDS patients admitted to Instituto de Infectologia Emilio Ribas between May 1990 and April 1992. From the bone marrow aspirates of the 125 patients, MAC was isolated from 23 (18.4%) and Mycobacterium tuberculosis was isolated from 9 (7.2%). Between 1985 and 1990, only 11 MAC isolations among 60,000 cultures obtained from human immunodeficiency virus-seronegative patients were documented in São Paulo. Hence, the minimal estimated rate of MAC infection in AIDS patients in this city was 23/2628, or 0.88%. These findings suggest that MAC infection is an important opportunistic infection, especially among a subset of patients with AIDS in Brazil who have clinical characteristics and risk activities similar to those associated with MAC infections in North America and Europe.