When are follow-up sputum smears actually examined in patients treated for new smear-positive pulmonary tuberculosis?

SETTING: All 44 non-private hospitals (four central, 22 district and 18 mission) in Malawi that registered and treated tuberculosis (TB) cases, October-December 2001. OBJECTIVES: To determine, in new smear-positive pulmonary tuberculosis (PTB) patients, for the 2-, 5- and 7-month smear examinations, 1) the proportion with smears examined and 2) the actual timing of smear examination. STUDY DESIGN: Retrospective data collection using TB registers, TB treatment cards and laboratory sputum registers. Timing of smear examinations was judged acceptable if 2-month smears were examined at 2 or 3 months, 5-month smears at 4, 5 or 6 months and 7-month smears at 6, 7, 8 or 9 months. RESULTS: Of 1994 patients, for those alive and on treatment, 78% had smears definitely examined at 2 months, 75% at 5 months and 74% at 7 months. Of these, 82% had smears examined at an acceptable time for the 2-month smear, 71% for the 5-month smear and 78% for the 7-month smear. Smears were examined after the 8-month treatment regimen for the 2- and 5-month smear in respectively 2% and 9% of patients. Smears were done more frequently in female than male patients, and in district/mission hospitals than central hospitals. Smears were done at acceptable times more frequently in younger than older patients and in mission/central hospitals than district hospitals. CONCLUSION: During supervision, the actual time of follow-up sputum smear examinations needs to be monitored more closely.     

The diagnosis of smear-negative pulmonary tuberculosis: the practice of sputum smear examination in Malawi.

SETTING: Forty hospitals in Malawi (3 central, 22 district and 15 mission) performing smear microscopy and registering tuberculosis patients. OBJECTIVE: To determine, in patients aged 15 years or above, 1) the proportion with smear-negative pulmonary tuberculosis (PTB) who had sputum smears examined, 2) the number of sputum smears examined per patient, and 3) the proportion of patients registered with smear-positive and smear-negative PTB. DESIGN: Data collection during three 6-month periods, from January 1997 to June 1998, using tuberculosis registers, laboratory sputum registers and quarterly reports. RESULTS: Of 6301 smear-negative PTB patients, 84% had sputum smears examined, the rate increasing from 76% in January-June 1997, to 85% in July-December 1997, to 89% in January-June 1998. Of patients who submitted sputum (where the number of smears was recorded), 99% had two or more smears examined and 93% had three smears examined. In district and mission hospitals performance improved over time, while in central hospitals results were more variable. During the same 18-month period 21 422 patients aged 15 years or more were registered with PTB: 59% with smear-positive PTB and 41% with smear-negative PTB; this pattern was similar in each 6-month period. CONCLUSION: The study suggests that it is reasonable to aim for a target of 90% or more of smear-negative PTB patients having sputum smears examined.     

Sputum smear conversion during directly observed treatment for tuberculosis

Setting: Treatment program for tuberculosis in a refugee camp in Thailand.Objectives: To determine the cumulative frequency of conversion of sputum smears examined by direct microscopy by month of treatment and to identify factors predicting failure to convert.Methods: Analysis of conversion based on three sputum smear examinations (performed monthly) in a cohort of patients with sputum smear-positive tuberculosis treated with a directly observed daily regimen containing rifampicin throughout. Nested case-control study of patients failing to convert definitively within four months compared to controls who did convert.Results: Sputum conversion after the 2-month intensive phase was 75.0%, with a range from 61.7% to 90.9% in patients with initially strongly- and weakly-positive smears, respectively. The strongest predictor identified for no definitive conversion within four months of treatment was a positive sputum smear result at the end of the 2-month intensive phase (adjusted relative odds 4.2, 95% confidence interval 1.5–11.4). Of those patients who did not convert, positive smears were an isolated phenomenon in 15, repeatedly in four who definitely converted with a prolongation of treatment, and persistently positive in two requiring a re-treatment regimen.Conclusions: Definitive sputum smear conversion is judged to be slower if a strict program of sputum smear examination is undertaken than under routine program conditions, but positive results late in the course are commonly an isolated phenomenon and possibly of little significance. Sputum smear results at two months strongly predict bacteriologic results beyond three months of treatment, and thus identify cases who might benefit from a prolongation of the intensive phase.     

The significance of the persistent presence of acid-fast bacilli in sputum smears in pulmonary tuberculosis.

STUDY OBJECTIVES: Identification of acid-fast bacilli (AFB) in the sputum smear at the completion of tuberculosis therapy is in some settings considered evidence of treatment failure. However, some patients with pulmonary tuberculosis (TB) will have positive smear results with negative sputum culture results at the end of therapy. The objectives of this study were to estimate the prevalence of persisting positive sputum smear results in patients with TB and to identify characteristics that distinguish patients with persistently positive sputum smear results who also had negative sputum culture results from patients identified as treatment failures. DESIGN: A population-based, historical cohort study with nested case control study. SETTING: British Columbia Division of Tuberculosis Control central case registry. PATIENTS: All 428 patients with culture-proven pulmonary TB in British Columbia over 7 years with sputum that was positive for AFB. METHODS: Review of laboratory data of all 428 patients, as well as clinical data of a subset of 30 patients with persistently positive smear results beyond 20 weeks. RESULTS: Sputum smears were positive for AFB in 205 patients (48%) at 4 weeks, in 30 patients (7%) at 20 weeks, and in 12 patients (3%) at 36 weeks. Of the patients with smear results that were persistently positive at 20 weeks, 23 (77%) had negative sputum culture results and 7 (23%) had positive sputum culture results (ie, they were treatment failures). Patients identified as treatment failures had more localized disease as shown on chest radiographs, had less radiographic improvement at follow-up, had a higher prevalence of drug resistance, and were less compliant with medications than patients with persistently positive smear results and negative culture results. No subject with a negative culture result relapsed over the 6- to 48-month observation period. CONCLUSION: Sputum that is persistently positive for AFB in patients in developed countries is more likely to be associated with negative culture results than with treatment failure.     

Survival and relapse rate of tuberculosis patients who successfully completed treatment in Vietnam.

SETTING: Reported tuberculosis (TB) cure rates are high in Vietnam with the 8-month short-course chemotherapy regimen. However, long-term treatment outcomes are unknown. OBJECTIVE: To assess survival and relapse rates among patients successfully treated for new smear-positive pulmonary tuberculosis (PTB). METHODS: A cohort of patients treated in 32 randomly selected districts in northern Vietnam were followed up 12-24 months after reported cure or treatment success for survival and bacteriologically confirmed relapse. Measurements included sputum smear examination, culture and interview for recent treatment history. RESULTS: Of 304 patients included in the study, no information was available for 31 (10%) and 19 (6%) had died. Bacteriology results were available for 244 (80%). The median interval between treatment completion and follow-up was 19 months. Relapse was recorded in 21/244 (8.6%, 95%CI 5.4-13), including 9 (4%) with positive sputum smears, 3 (1%) with negative smears but positive culture and 9 (4%) who had started TB retreatment. Four of 12 culture-positive relapse cases (33%) had multidrug-resistant strains. If the definition of relapse was extended to include death, reportedly due to TB, the relapse proportion was 26/263 (9.9%, 95%CI 6.6-14). CONCLUSION: A substantial proportion of patients (15%) had died or relapsed after being successfully treated for TB in northern Vietnam.     

From suspect to patient: tuberculosis diagnosis and treatment initiation in health facilities in South Africa

SETTING: Thirteen primary health care (PHC) facilities in the Stellenbosch District, South Africa. OBJECTIVE: To assess the use of a sputum register to evaluate the tuberculosis (TB) diagnostic process and the initiation of TB treatment in selected PHC facilities in a country with a centralised laboratory system. DESIGN: This prospective study was conducted between April 2004 and March 2005. The names of all individuals submitting sputum samples for TB testing were noted in a newly introduced sputum register. We classified all TB suspects with two positive smears as TB cases and consulted TB treatment registers until 3 months after sputum submission to determine how many had started treatment. RESULTS: A total of 4062 persons aged > or =15 years submitted sputum samples, of whom 2484 were TB suspects. There were 2037 suspects with at least two results, 367 (18%) had at least two positive smears and 64 (17%) of these did not start treatment (initial defaulters). Over the entire diagnostic process, up to 5% of TB cases were missed, and up to 26% did not start treatment and were not reported. CONCLUSION: By correcting diagnostic weaknesses identified in the sputum register, PHC facilities will be able to detect, treat and cure a higher percentage of TB patients.     

The results of 9-month isoniazid-rifampin therapy for pulmonary tuberculosis under program conditions in San Francisco

The outcome of treatment for pulmonary tuberculosis using isoniazid and rifampin for 9 months supplemented by ethambutol for the initial 2 months was evaluated in a cohort of 233 patients. All patients had sputum cultures positive for Mycobacterium tuberculosis sensitive to isoniazid and rifampin. Of the 233 patients, 200 completed the regimen without change. Four patients had adverse reactions necessitating discontinuation and four became pregnant and had ethambutol substituted for rifampin. All eight were treated successfully with altered regimens. Ten patients were lost to follow-up, seven died, and eight were transferred to other jurisdictions. No patients failed to convert their sputum during therapy. At completion of therapy, three patients (1.5%) were found to have positive sputum. Follow-up 6 months after completion of treatment in 174 successfully treated patients revealed four (2.3%) with positive sputum. No further relapses were detected on evaluation 12 months after treatment was completed. All seven patients who failed therapy or relapsed were retreated successfully using the same regimen. These data provide a reference standard against which newer treatment regimens, such as the 6-month regimen currently in use, can be compared. In addition, the value of routine evaluations in detecting relapses at the time treatment is completed and 6 months later was substantiated, but 12-month follow-up was not useful.     

Influence of pre-treatment bacillary load on treatment outcome of pulmonary tuberculosis patients receiving DOTS under revised national tuberculosis control programme

OBJECTIVE: To study the influence of initial bacillary load on sputum conversion rates and treatment outcome of new smear positive pulmonary tuberculosis patients. METHODS: A retrospective study was done among 2938 new smear positive pulmonary tuberculosis patients, registered at the peripheral centres, covering a population of 1.6 million in Delhi, India. The patients pre-treatment sputum smears were graded as 1+, 2+ or 3+ based on three samples. Patients were given intermittent short-course chemotherapy under supervision and the treatment outcome was analysed. RESULTS: Sputum conversion rates among patients graded as sputum 3+ and rest of the patients (combined graded sputum 1+ and 2+) at the end of two months were 62.2% and 76.8% respectively (p<0.001), and at the end of three months were 81.3% and 89.5% respectively (p<0.001). Cure rates among same group of patients were 76.6% and 85.1% respectively (p<0.001), and failure rates were 7.7% and 4.5% respectively (p<0.001). CONCLUSIONS: Under field conditions even with directly observed treatment (DOT) new smear positive patients with heavy bacillary load showed statistically significant poor sputum conversion rates at two and three months and higher failure rates as compared to patients with lesser bacillary load. To investigate possible reasons for this poor response and possible solutions further studies are needed.     

Efficacy and safety of short-term bleach digestion of sputum in case-finding for pulmonary tuberculosis in Ethiopia.

BACKGROUND: In many settings, the diagnosis of pulmonary tuberculosis depends on sputum microscopy. However, this technique has low sensitivity. We studied the efficacy and safety of sputum digestion with bleach prior to Ziehl-Neelsen (ZN) staining. METHODS: Positive sputum smears were assessed for staining quality and viability of mycobacteria after varying bleaching times. Two hundred smears were then prepared from the first, second and third sputum sample of tuberculosis suspects. Equal amounts of 5% bleach were added to the remaining first sputum and ZN smears were prepared. FINDINGS: Optimal quality and staining was achieved with 30-45 min of bleaching. No growth was observed from positive samples after 15 min. Bleached specimens had 26% (52/200) positivity compared to 17.5% (35/ 200) of unbleached smears (P < 0.001). The bleached smears had 92.3% sensitivity, 93.4% specificity, 78.3% and 97.7% positive and negative predictive values, respectively, against a case definition. Ten patients failed to submit a second or third sputum. Six patients were positive on either the standard or bleach-digested smears, or both. INTERPRETATION: Bleach digestion is simple, cheap and kills mycobacteria. Its positivity rate is as good as three standard smears. This method has the potential to improve over-burdened services in developing countries.     

Induced sputum improves the diagnosis of pulmonary tuberculosis in hospitalized patients in Gaborone, Botswana

SETTING: Low sensitivity of acid-fast bacilli (AFB) sputum smears and absence of productive cough are obstacles to the diagnosis of pulmonary tuberculosis (PTB) in hospitals that lack access to bronchoscopy. OBJECTIVES: To evaluate induced sputum, gastric content, blood and urine specimens to improve PTB diagnosis in patients not diagnosed by expectorated sputum AFB smears. DESIGN: Patients admitted to the medical wards of a large public hospital in Gaborone, Botswana, were prospectively enrolled if they had symptoms consistent with PTB, an abnormal chest radiograph, were treated empirically with anti-tuberculosis chemotherapy or had no improvement on antibiotics, and had a non-productive cough or AFB smear-negative sputum. Induced sputum was stained for AFB and Mycobacterium tuberculosis cultures were performed on induced sputum, gastric contents, urine and blood. RESULTS: Of 140 patients meeting the enrollment criteria, 113 (81%) were human immunodeficiency virus (HIV) positive. Fifty-seven (41%) had PTB based on positive cultures from one or more sites, including 48 (84%) from induced sputum, 17 (30%) urine, 13 (23%) gastric contents and 7 (12%) blood. AFB smears were positive in only 18 (32%) culture-proven PTB cases. CONCLUSION: Induced sputum cultures greatly enhanced M. tuberculosis detection in patients with a high prevalence of HIV/AIDS in a hospital without access to bronchoscopy.     

Treatment outcome among Rwandan and Burundian refugees with sputum smear-positive tuberculosis in Ngara, Tanzania.

SETTING: Tuberculosis programme in six camps (Benaco, Musuhura, Lumasi, Lukole, Keza and Kitali) for Rwandan and Burundian refugees in Ngara district, Tanzania, where treatment was directly observed throughout. OBJECTIVES: To evaluate the treatment outcome of sputum smear-positive tuberculosis cases recruited in refugee camps in Ngara, and to determine the cumulative frequency of conversion of sputum smears by direct microscopy. DESIGN: Retrospective review of tuberculosis registers from January 1995 to December 1999. RESULTS: Of 546 patients with smear-positive tuberculosis who were notified in the programme, 363 (66.5%) had completed treatment and were bacteriologically cured after 7 months, 10.9% had died, 7.1% had defaulted and 14.5% had transferred out. Sputum conversion after the 2-month intensive phase was 88%, and increased to 99% after 7 months of chemotherapy. CONCLUSION: The involvement of the Tanzania NTLP in collaboration with health NGOs has led to a satisfactory outcome. These data suggest that it is possible for tuberculosis control programmes to perform successfully in refugee settings.     

Short-course chemotherapy of pulmonary tuberculosis in pneumoconiotic patients

This is the first prospective clinical trial recorded to date of short-course chemotherapy in pulmonary tuberculosis complicated by pneumoconiosis. Forty-eight anthrasillicotic and 11 silicotic patients with previously untreated pulmonary tuberculosis completed 9-month, short-course chemotherapy regimens: 2 months of daily streptomycin, isoniazid, rifampicin, and pyrazinamide followed by daily isoniazid and rifampicin for 7 months (2SHRZ/7HR). There were 3 treatment failures (5%). The remaining 56 patients (95%) all had their sputum converted within 4 months (mean, 1.5 months). Bacteriologic relapses were noted in 3 patients (5%) after 18 to 40 months of follow-up (mean, 28.4 months). The relapses occurred within 7 months after chemotherapy was stopped. There were 2 deaths from nontuberculosis causes during the follow-up period. Fifty-one patients (90%) remained bacteriologically sterile for 28.4 +/- 6.1 months. These results suggest that the 2SHRZ/7HR regimen is satisfactory in treating anthrasilicotic or silicotic patients with pulmonary tuberculosis, though antituberculosis chemotherapy seemed less effective in patients with pneumoconiosis than in those without pneumoconiosis.     

Screening tuberculosis suspects using two sputum smears.

SETTING: Ntcheu district hospital, Malawi. OBJECTIVE: To assess a screening strategy for tuberculosis (TB) suspects using two sputum smears. DESIGN: A strategy of screening all TB suspects with two sputum smears for 6 months (1 July-31 December 1998) was compared with the period 1 January to 30 June 1998 during which the strategy of screening TB suspects with three sputum smears was in use. All chest radiographs of patients with negative sputum smears were assessed, and in those with pulmonary cavities and extensive disease a third sputum smear was examined. Data were collected from the laboratory sputum register and the TB register. The two 6-month periods were compared. RESULTS: In the laboratory register, using a two-sputum strategy, 186 (16%) of 1152 TB suspects were smear-positive, a result that was no different than when the three-sputum strategy was used, where 173 (16%) of 1106 TB suspects were smear-positive. The clinical pattern of TB using the different screening strategies was similar, with 58% of registered patients smear-positive with the two-sputum strategy and 54% smear-positive with the three-sputum strategy. In the first 6 months 3177 sputum smears were examined compared to 2266 smears in the second 6 months, a 29% reduction in the number of smears examined. The cost of consumables using the strategy of three sputum smears was USD $731 compared with USD $521 using the strategy of two sputum smears. C O N C L U S I O N S: Screening TB suspects using two sputum smears is as effective as screening using three sputum smears, and is associated with less laboratory work and savings in costs.     

Comparison of scanty AFB smears against culture in an area with high HIV prevalence.

To verify among tuberculosis (TB) suspects attending hospitals in Abuja, Nigeria, if sputum smears graded as scanty are false-positive, sputum smears from 1068 patients were graded with the International Union Against Tuberculosis and Lung Disease classification. One specimen was cultured. Eight hundred and twenty-four (26%) smears were positive, 137 (4%) scanty and 2243 negative. Of 1068 cultures, 680 (64%) were positive. One hundred and thirty (95%) scanty and 809 (98%) positive smears were culture-positive. Twelve of 18 patients with a single scanty smear and 51 of 52 with > or = 2 scanty smears were culture-positive. Fewer than < 5% scanty results, < 1% of the patients treated for TB, are false-positive.     

Tuberculous pleural effusion: 6-month therapy with isoniazid and rifampin.

We have shown that 6-month therapy with isoniazid (INH) and rifampin (RIF) is adequate for pulmonary tuberculosis when tubercle bacilli are less numerous, i.e., smear negative, culture positive. Tuberculous exudative pleural effusion contains small bacterial populations, as often demonstrated by negative smears and fewer positive cultures. Therefore, in 1980, we started treating tuberculous pleural effusion with a therapy protocol consisting of INH 300 mg plus RIF 600 mg daily for 1 month, followed by INH 900 mg plus RIF 600 mg twice weekly for another 5 months (total, 6 months). From January 1980 to September 1990, 198 patients with an average age of 62.6 years were treated in this manner. Associated pulmonary infiltration was present in 92 patients, of whom 50% yielded positive sputum cultures. Other medical conditions as "risk factors" were present in 30%. Therapy was not completed in 36 patients because of death, relocation, noncompliance, and drug side effects. Treatment failed during therapy in only 1 patient. Side effects of the drugs occurred in 13 (6.6%) patients, but major side effects were encountered in only three (1.5%), two with toxic hepatitis and one with thrombocytopenia. The full 6-month therapy was completed by 161 patients. During follow-up from 2 to 133 months (median, 46 months), none of the 161 patients had relapse. An overall success rate of 99% was achieved in 162 patients with only 1 failure during therapy. Thus, 6-month therapy with INH plus RIF is adequate in tuberculous exudative pleural effusion, even when associated with smear-negative (3 specimens) culture-positive pulmonary tuberculosis.     

Unexpected pulmonary involvement in extrapulmonary tuberculosis patients

BACKGROUND: This study aimed to assess the utility of sputum examinations and chest radiographs (CXRs) in patients with extrapulmonary tuberculosis (XPTB) to detect pulmonary involvement of tuberculosis (TB). METHODS: We studied 72 XPTB patients who were managed through the TB Program, King County, WA, from January 2003 through November 2004. RESULTS: The two most common sites of XPTB were the lymph nodes (36 [50%]) and pleura (12 [17%]). Thirty-five of 72 XPTB patients (49%) had abnormal CXR findings. Sputum was not obtained from 15 patients despite sputum induction. Of the 57 patients from whom sputum was collected, 30 (53%) had abnormal CXR findings, 5 (9%) had sputum smears that were positive for acid-fast bacilli, and 12 (21%) had sputum cultures that were positive for Mycobacterium tuberculosis. Weight loss was significantly associated with positive sputum culture findings in a multivariate analysis (odds ratio, 4.3; 95% confidence interval, 1.01 to 18.72; p = 0.049). There was no significant difference in the occurrence of positive sputum culture results between patients with abnormal CXR findings and those with normal CXR findings (7 of 30 patients [23%] vs 5 of 27 patients [19%], respectively; p = 0.656). Of 24 HIV-negative XPTB patients with normal CXR findings, 2 patients (8%) had positive sputum culture findings. CONCLUSIONS: CXR results did not reliably differentiate XPTB patients with and without positive sputum culture findings. Some XPTB patients had positive sputum culture results despite normal CXR findings and negative HIV status. Weight loss in XPTB patients was associated with positive sputum culture results. Sputum examinations in XPTB patients, regardless of the CXR results, may identify potentially infectious cases of TB.     

2月末结核分枝杆菌阳性初治肺结核患者菌型鉴定结果分析

目的分析深圳市南山区2月末结核分枝杆菌阳性肺结核患者的分枝杆菌分布情况,为诊断与治疗分枝杆菌感染提供参考依据。方法 2013年1月至2015年12月深圳市南山区痰结核分枝杆菌阳性的初治肺结核患者治疗2月末仍结核分枝杆菌阳性患者进行菌型鉴定并进行结果分析。结果 617例结核分枝杆菌阳性肺结核患者经2个月强化期治疗后,46例患者出现2月末结核菌阳性,其中涂片阳性为33例,涂片阴性而培养阳性为13例;涂片阳性患者中19例培养阴性,10例为结核药物敏感菌,4例为非结核分枝杆菌;涂阴培阳患者中1例为结核药物敏感菌,12例为非结核分枝杆菌;16例非结核分枝杆菌经分型鉴定后,7例脓肿分枝杆菌,9例戈登分枝杆菌。结论肺结核患者可能继发非结核分枝杆菌感染,抗结核治疗2月末肺结核病人应及时留取痰标本做结核菌涂片,培养和菌种鉴定,为进一步诊断和制定个体化疗方案提供依据。     

Analysis of chronic excretors of Mycobacterium bacilli in Aichi Prefecture]

Among the patients diagnosed as having pulmonary tuberculosis who were newly admitted to six major tuberculosis centers in Aichi Prefecture during the period from January 1, 1982 to December 31, 1986, 73 patients were chronic excretors of Mycobacterium bacilli (chronics), whose sputum cultures tested positive at both 11 and 12 months after admission. In this study, those 73 patients were analyzed in March 1988. If the patient was still hospitalized at that time, the patient was re-evaluated six months later. The life table method was used for analysis of clinical procedures. For the analysis of risk factors for chronics, 37 patients who were treated after 1971 when RFP was available for treatment were used. The results in this study are as follows: 1. A total of 49.3% of the patients were determined chronics (those who had initial chemotherapy before 1970 when RFP was not available). This result suggests that the use of RFP may contribute to the reduction of chronics. 2. Patient delay in diagnosis, as well as irregular chemotherapy, was one of the factors for the development of chronics. 3. In the chronics, many patients showed severe findings in their chest X-rays, high bacillary counts in the sputum, and low drug-sensitivity bacilli when treated with the major anti-tuberculosis drugs. 4. The rate of chronics from newly admitted patients with positive sputum cultures following the initial chemotherapy treatment was 1.3%. This rate could increase following longer observation periods. 5. Chronics were more prevalent in patients with Type I (extensive cavitary type) findings in the chest X-rays, and positive sputum smears for Mycobacterium bacilli in the clinical findings when compared with all newly registered active tuberculosis patients during the same period in Aichi Prefecture. 6. Concerning the outcome, 55 patients were discharged (17 improved; 13 personally released; 25 deceased) while 18 remain hospitalized. Among those discharged patients, 17 patients were released as a result in improved health while 25 died. These results indicate poor prognosis. Using the life table method, the estimated mortality rate is 49.7%, and the negative sputum rate is 30.5% five years later. 7. Using a multivariate analysis on the prognosis, the risk factor was greatest for poor prognosis for those patients who had Type I findings in their chest X-rays, initial chemotherapy before 1970, complications, and that were male. 8. The patients with improved health, were more sensitive to the drugs applied when compared to the fatal patients. 9. Careful chemotherapy during the first two years may contribute to the reduction of chronics.     

Completeness and timeliness of treatment initiation after laboratory diagnosis of tuberculosis in Gaborone, Botswana.

SETTING: Gaborone, the capital of Botswana. OBJECTIVE: To determine the time from positive sputum smear microscopy for acid-fast bacilli (AFB) to initiation of therapy, and to identify risk factors for delays. DESIGN: Retrospective cohort study of medical records and surveillance data for patients with positive smear microscopy and newly diagnosed tuberculosis (TB) from January to May 1997. Treatment delay was defined as more than 2 weeks from the first positive sputum smear to the initiation of TB treatment. RESULTS: Of 127 patients identified, 15 (11.8%) had treatment delay, 13 (10.2%) had an incomplete workup (only one smear performed) and were not registered for TB treatment, and six (4.5%) had two or more positive smears but were not registered for TB treatment. Risk factors for treatment delay or non-registration included TB patients who had been diagnosed in a hospital outpatient setting vs. a clinic (RR 2.9, 95% CI 1.2-3.6, P = 0.02), or in a high volume vs. low volume clinic (RR 2.2, 95% CI 1.2-5.3, P = 0.01). CONCLUSION: More than a quarter of the smear-positive TB patients identified had treatment delay or no evidence of treatment initiation. Proper monitoring of laboratory sputum results and suspect TB patient registers could potentially reduce treatment delays and patient loss.     

Factors associated with time to sputum smear conversion in active pulmonary tuberculosis.

OBJECTIVE: To ascertain the factors affecting the time between the initiation of treatment and obtaining three negative sputum smears. DESIGN: In a study of 109 patients with pulmonary tuberculosis, the main variable was the period during which the patients had sputum smears once treatment was initiated. Multivariate analysis (multiple linear regression) was performed to document those variables independently associated with time to conversion. RESULTS: The patients had positive smears for a mean of 28.63 days. The most frequent radiographic pattern was cavitary disease (36.7%). HIV co-infection was present in 38.5% of the patients. HIV-infected patients showed a cavitation pattern in only 9.6% vs 52.2% of patients without HIV infection (P < 0.001). The variables that showed a statistically significant and independent relationship with the time to sputum smear conversion were pulmonary radiographic pattern, age and erythrocyte sedimentation rate (ESR). CONCLUSIONS: ESR, age and the presence of cavitary disease seem to be factors associated with a longer time to sputum smear conversion in patients with active pulmonary tuberculosis. However, HIV co-infection is associated with a shorter time to sputum conversion. A key factor is therefore the presence or not of cavitation, independently of HIV infection.