The true prevalence rates of multidrug-resistant tuberculosis (MDRT) are unknown for most regions of Russia. This study was conducted in the Samara Region that differs from other regions in the rapid spread of HIV infection. The purpose of this study was to determine the primary and acquired resistance of Mycobacterium tuberculosis (MBT) to first-line antituberculous drugs in patients from civil and penitentiary sectors and to reveal risk factors of drug resistance of MBT. Six hundred patients (309 civilians and 291 prisoners who had been bacteriologically diagnosed as having tuberculosis. The authors have established the following:--in new cases, primary drug resistance is as follows: to isoniazid [38.9% (95% CI, 31.3-36.9%)], to rifampicin [25.9% (95% CI, 19.4-33.4%)] and to MDRT [23.0% (95% CI, 16.7-30.3%)];--in prisoners, the primary resistance of MBT was statistically more significant than in civilians;--male sex, in adequate prior or current treatment for tuberculosis for more than 4 weeks, the presence of fibrocavernous tuberculosis and previous prison stay are essential risk factors of the development of resistance of MBT to both any first-line drug and MDRT;--HIV infection is unassociated with resistance.
The spectrum of drug-resistance of rifampicin-resistant M. tuberculosis strains to other first-line antituberculous drugs was studied. Streptomycin resistance was found to be prevalent in the structure of monoresistance. Resistance to two agents--isoniazid and streptomycin--was more common in the structure of polyresistance; that to a combination of isoniazid, rifampicin, and streptomycin was seen in the structure of multidrug resistance. The rifampicin-resistant strains were also resistance to isoniazid and streptomycin in 95.1 and 98.7% of cases, respectively. Resistance to isoniazid, streptomycin, and ethambutol occurs more frequently when cytosine is substituted for thymidine (TCG-->TTG) in codon 513 of the rpoB gene.
Statistics for the last 6 years show a trend to growing number of new cases with tuberculosis of the lungs with drug-resistant pathogen. In recurrent tuberculosis multiple drug resistance (MDR) was three times higher than in new cases. Treatment efficacy depended on MDR and patients' compliance. The results of the basic treatment course were unstable: many patients had exacerbation within 3-4 years after therapy, many patients died, especially those with M. tuberculosis resistant to many drugs.
Xpert MTB/RIF testing for Mycobacterium tuberculosis and rifampin resistance is being used extensively in countries with a high burden of TB. However, recent evidence suggests that it may not have the same accuracy or impact in high-income, low-burden TB countries.
A prospective, pragmatic study was done between March 2012 and March 2014 to determine the feasibility, accuracy, and impact on TB disease management provided by the Xpert test in a remote, medically underserved, predominantly Inuit population in Iqaluit, Nunavut, Canada.
A total of 453 Xpert tests were run on sputum samples from 344 patients with suspected TB. Twenty-seven patients were identified as having active TB disease by culture. There were no cases of drug-resistant TB. Using culture as the gold standard, one Xpert test compared with one, two, or three sputum samples cultured per patient had a sensitivity of 85% (95% CI, 66%-95%) and a specificity of 99% (95% CI, 97%-100%) for detection of M tuberculosis. The indeterminate rate was 4.4% of all samples run. Treatment initiation was significantly shortened using Xpert vs the national standard of three smears (1.8 days vs 7.7 days, P
Provincial tuberculosis (TB) services, British Columbia, Canada.
To estimate the risk of drug resistance among foreign-born TB patients and to identify risk factors associated with drug resistance.
Using the provincial TB database, we examined all culture-positive foreign-born TB patients for the years 1990-2001. The risk of having a drug-resistant isolate was estimated according to country and region of origin.
Of 1940 foreign-born patients identified, 247 (12.7%, 95%CI 11.3-14.3) cases had isolates resistant to at least one of the first-line drugs, with 160 (8.3%) isolates showing monoresistance, 24 (1.2%) multidrug resistance (resistance to at least isoniazid and rifampin) and 63 (3.3%) polyresistance (resistance to two or more drugs, excluding MDR). Country-specific analysis showed that immigrants from Vietnam (adjusted OR 2.12, 95%CI 1.37-3.27) and the Philippines (adjusted OR 1.71, 95%CI 1.10-2.66) had a significantly higher risk of resistance than other immigrants. In addition, the risk was the highest for younger TB patients and patients with reactivated disease (adjusted OR 2.12, 95%CI 1.09-4.09).
The risk of drug resistance was the highest among foreign-born patients from Vietnam and the Philippines. These findings should assist clinicians in prescribing and tailoring anti-tuberculosis regimens for immigrants more appropriately.
The paper analyzes the detection rate of drug-resistant (DR) Mycobacterium tuberculosis (MBT) in Yakutia. The proportion of DR MBT strains taken from bacterial isolating patients with pulmonary tuberculosis was found to be 70% and to have no tendency for decrease. The structure of DR MBT deteriorated due to the increase in multidrug-resistance (MDR). MDR in MBT was recorded in 45-50% of cases. Examination of lung resection specimens from patients with abacillary tuberculosis identified a population of typical MBT. The authors regarded this phenomenon as latent MBT carriage. The specific feature of this population is that it preserves a high metabolic activity in latency; DR was established in 76.3% of patients. Its most malignant form - MDR was established in a third (31.6%) of the patients. Under certain conditions, this mycobacterial infection may be of epidemic value in the spread of MBT in general and MDR strains in particular. Solution of the problems associated with the surgical treatment of patients with MDR tuberculosis may be beneficial in diminishing the most dangerous reservoir of tuberculous infection. Surgical intervention in MDR tuberculosis is one of the basic treatments.
BACKGROUND AND METHOD: The decline of tuberculosis (TB) in the Swedish population since the middle of the 20th century resulted in decreased awareness of the disease. Increased migration from TB-endemic countries has resulted in new cases and risk of transmission. A day care provider was diagnosed with cavitary TB after being symptomatic for 5 months. We describe the contact tracing at the day care center, the clinical and radiographic findings, and treatment of the infected children. RESULTS: We stratified the children by contact with the source case and examined the most exposed first. Thirty-two of 53 attending and 3 of 84 visiting preschool children were infected. All of them had spent at least 3 days at the center. Symptoms were usually mild and nonspecific. Seventeen children had pulmonary radiographic changes compatible with primary TB, and one had miliary TB. The radiographic resolution was slow, with normalization in 50% after 12 months. Eighteen months after termination of treatment, there have been no relapses. The children with latent infection were treated with rifampin for 4 months and none has developed TB. CONCLUSIONS: The manifestations of primary TB in children today are similar to those described 50-70 years ago. The tuberculin skin test is an effective tool for contact tracing in an unvaccinated, previously nonexposed childhood population. Rapid detection of contagious patients and thorough contact investigation remain our most important means to reduce transmission.
To assess the validity of current estimates of the noncontagiousness of sputum smear-positive respiratory tuberculosis (TB) on treatment.
A descriptive analysis of the mycobacteriologic response to treatment.
A TB inpatient unit of a Canadian hospital.
Thirty-two HIV-seronegative patients with moderate to advanced sputum smear-positive respiratory TB were treated with uninterrupted, directly observed, weight-adjusted isoniazid, rifampin, and pyrazinamide. Each patient's initial isolate was drug susceptible and each patient's sputum mycobacteriology was systematically followed until 3 consecutive sputum smears were negative on 3 separate days.
The time to smear conversion varied remarkably (range, 8 to 115 days; average, 46 days) and was influenced by sputum sampling frequency. Only 3 patients (9.4%) had smear conversions by 14 days and only 8 (25%) had smear conversions by 21 days, the average time it took for drug susceptibility test results to become available. During the first 21 days of treatment, the semiquantitative sputum smear score decreased rapidly and the time to detection of positive cultures doubled. Within the time to smear conversion, virtually all smear-positive specimens (98%) were culture positive and only 34% of the patients had culture conversions (ie, 3 consecutive negative cultures).
Current estimates of the noncontagiousness of sputum smear-positive respiratory TB on treatment (for 14 days, for 21 days, or until smear conversion) are estimates of relative noncontagiousness. They do not signal absolute noncontagiousness (culture conversion). Semiquantitative smear and time-to-detection data suggest that respiratory isolation beyond 21 days of optimal treatment should be selective.