Clinical significance of smear positivity for acid-fast bacilli after ≥5 months of treatment in patients with drug-susceptible pulmonary tuberculosis

Wahid UNI, Ling LL, Liansim SMS, Oon J, Balakrishnan MN, Ng WL, Cheong AT. Prevalence and associated factors of delayed sputum smear conversion in patients treated for smear positive pulmonary tuberculosis: A retrospective follow up study in Sabah, Malaysia

INTRODUCTION

Tuberculosis remains a major health problem globally and in Malaysia, particularly in the state of Sabah. Delayed sputum conversion is associated with treatment failure, drug-resistant tuberculosis and mortality. We aimed to determine the prevalence of delayed sputum conversion among smear positive pulmonary tuberculosis (PTB) patients and its associated factors in Sabah, Malaysia.

METHODS

A retrospective follow up study on all patients newly diagnosed with smear positive pulmonary tuberculosis from 2017 to 2019 was conducted at three government health clinics in Sabah, utilizing data from a national electronic tuberculosis database and medical records. Descriptive statistics and binary logistic regression were applied for data analysis. The outcome of the study was the sputum conversion status at the end of the two-month intensive treatment phase with either successful conversion to smear negative or non-conversion.

RESULTS

374 patients were included in the analysis. Our patients were generally younger than 60 years old with no medical illness and varying proportions of tuberculosis severity as judged by radiographic appearance and sputum bacillary load upon diagnosis. Foreigners constituted 27.8% of our sample. 8.8% (confidence interval: 6.2-12.2) did not convert to smear negative at the end of the intensive phase. Binary logistic regression showed that older patients ≥60 years old (adjusted odds ratio, AOR = 4.303), foreigners (AOR = 3.184) and patients with higher sputum bacillary load at diagnosis [2+ (AOR = 5.061) and 3+ (AOR = 4.992)] were more likely to have delayed sputum smear conversion.

CONCLUSION

The prevalence of delayed sputum conversion in our study was considerably low at 8.8% with age ≥60 years old, foreigners and higher pre-treatment sputum bacillary load associated with delayed conversion. Healthcare providers should take note of these factors and ensure the patients receive proper follow up treatment.

Predominance of Other Pathogenic Bacteria among Presumptive Tuberculosis Cases Attending Tuberculosis Clinics in Mwanza, Tanzania: A Cross-Sectional Laboratory-Based Study

This study was designed to determine the prevalence and co-infection of Mycobacterium tuberculosis and other pathogenic bacteria among presumptive cases of tuberculosis (TB) at selected hospitals in Mwanza, Tanzania. GeneXpert and conventional bacteriological culture and sensitivity were used for the detection of TB and other pathogenic bacteria, respectively. STATA version 13.0 was used for data analysis. The median (IQR) age of participants was 33 (19−51) years with males forming more than half (i.e., 59% (158/264)) of the participants. Microscopically, 29.5% (78/264) of the patients had polymorphonuclear leucocytes in the sputum samples. Approximately 7.2% (19/264), 16.3% (43/264), and 1.1% (3/264) of participants had TB, other pathogenic bacteria, and co-infections, respectively. One sample had growth of two other bacteria, resulting in a total of 44 isolated bacteria with the predominance of Gram-negative bacteria at 75.0% (33/44). The predominant species isolated was the Klebsiella pneumoniae complex at 52.3% (23/44). Overall, 27.3% (9/33) of GNB were resistant to third-generation cephalosporins, while Gram-positive bacteria were more resistant to erythromycin at 63.6% (7/11). Good quality sputa had a significantly higher yield of pathogenic bacteria than poor quality sputa (37.2% vs. 7.5%, p < 0.001). Presumptive TB cases were predominantly infected with other pathogenic bacteria than M. tuberculosis. Therefore, other pathogenic bacteria should be considered when attending presumptive TB cases to ensure favorable treatment outcomes.

FIRST LINE ANTI-TUBERCULOSIS DRUG RESISTANCE PATTERN IN MULTIDRUG-RESISTANT PULMONARY TUBERCULOSIS PATIENTS CORRELATE WITH ACID FAST BACILLI MICROSCOPY GRADING

Multidrug-resistant tuberculosis (MDR-TB) is a global public health crisis. Acid-fast bacilli (AFB) gradation in sputum examination is an important component in Pulmonary Tuberculosis (PTB) diagnosis and treatment outcome monitoring. Previously treated pulmonary TB patients with a higher AFB smear gradation may have higher rates of acquired resistance. Patients with a higher AFB grade indicate a higher bacillary load and had higher rates of acquired resistance. This study aims to evaluate the correlation between AFB gradation and first-line anti-TB drug resistance patterns in MDR pulmonary TB patients. This was a retrospective study conducted from August 2009 to April 2018 in Dr. Soetomo Hospital. Sputum samples were taken from MDR PTB patients. Sputum smear examination was done using Ziehl–Neelsen staining and gradation was measured according to IUATLD criteria. Samples with positive smear were evaluated for resistance patterns based on culture and resistance tests using the MGIT 960 BACTEC System. There were 433 sputum samples with AFB positive collected from MDR PTB patients. Resistance to RHES was found in 22 (14%) AFB +1, 19 (15%) AFB +2, and 29 (20%) AFB +3. Resistance to RHS was found in 22 (14%) AFB +1, 12 (9%) AFB +2, and 13 (9%) AFB +3. Resistance to RHE was found in 39 (25%) AFB +1, 38 (29%) AFB +2, and 35 (24%) AFB +3. Resistance to RH was found in 74 (47%) AFB +1, 61 (47%) AFB +2, and 69 (47%) AFB +3. Statistic analysis by Spearman test showed that there was no significant correlation between AFB gradation and first-line anti-TB drug resistance patterns. Acquired resistance to RHES can also found in lower bacillary load AFB +1.

Additional considerations for "checklists to guide the supportive and critical care of tuberculous meningitis"

Checklists are pivotal in the systematic assessment of critically ill patients, pre-operative assessments and for patients with multisystem involvements. Management of tuberculous meningitis is challenging due to prolonged hospital stay, multiple neurological complications like seizures, stroke, raised intracranial tension, stroke, neurosurgical interventions, multiple invasive procedures, health-care-associated sepsis, and ventilation. All these complications are managed by separate checklists to avoid treatment-related errors. The current manuscript aims to ensure completeness of inpatient care addressing issues addressing diagnostic issues, supportive care, and intensive care related issues.

A retrospective analysis of treatment outcomes of drug-susceptible TB in Kazakhstan, 2013-2016

Kazakhstan has a high burden of multidrug-resistant tuberculosis (TB). The patient-centered National Program for the treatment and prevention of TB has been implemented in Kazakhstan. The program is aimed at meeting the needs of patients and expansion of the outpatient treatment of TB in the country.The aim of the study was to compare the efficacy of the outpatient and inpatient treatment of drug-susceptible TB.This study was a retrospective cohort study.A total of 36.926 TB cases were included. The majority of patients were treated as inpatients. The socioeconomic factors, sex, age, HIV status, and other diagnostic factors (e.g., sputum smear results, extrapulmonary disease) may serve as risk factors to estimate the likely TB treatment outcome. The outpatient treatment of drug-susceptible TB seems to be a comparable option to the inpatient treatment in terms of efficacy.The socioeconomic factors are the main modifiable risk factors for treatment failure. The outpatient treatment of drug-susceptible TB is safe and effective.

Mycobacterium africanum (Lineage 6) shows slower sputum smear conversion on tuberculosis treatment than Mycobacterium tuberculosis (Lineage 4) in Bamako, Mali

Objective

Ancestral M. tuberculosis complex lineages such as M. africanum are underrepresented among retreatment patients and those with drug resistance. To test the hypothesis that they respond faster to TB treatment, we determined the rate of smear conversion of new pulmonary tuberculosis patients in Bamako, Mali by the main MTBc lineages.

Methods

Between 2015 and 2017, we conducted a prospective cohort study of new smear positive pulmonary tuberculosis patients in Bamako. Confirmed MTBc isolates underwent genotyping by spoligotyping for lineage classification. Patients were followed at 1 month (M), 2M and 5M to measure smear conversion in auramine (AR) and Fluorescein DiAcetate (FDA) vital stain microscopy.

Result

All the first six human MTBc lineages were represented in the population, plus M. bovis in 0.8% of the patients. The most widely represented lineage was the modern Euro-American lineage (L) 4, 57%, predominantly the T family, followed by L6 (M. africanum type 2) in 22.9%. Ancestral lineages 1, 5, 6 and M. bovis combined amounted to 28.8%. Excluding 25 patients with rifampicin resistance, smear conversion, both by AR and FDA, occurred later in L6 compared to L4 (HR 0.80 (95% CI 0.66–0.97) for AR, and HR 0.81 (95%CI 0.68–0.97) for FDA). In addition we found that HIV negative status, higher BMI at day 0, and patients with smear grade at baseline ≤ 1+ were associated with earlier smear conversion.

Conclusion

The six major human lineages of the MTBc all circulate in Bamako. Counter to our hypothesis, we found that patients diseased with modern M. tuberculosis complex L4 respond faster to TB treatment than those with M. africanum L6.

Outcomes of pulmonary tuberculosis in patients with discordant phenotypic isoniazid resistance testing

INTRODUCTION

The discrepancy rates of drug susceptibility testing (DST) results between solid and liquid media have been reported to range from 2.4 to 7.4% for isoniazid. Most isolate with isoniazid DST discrepancies between solid and liquid media test as susceptible on solid medium and resistant in liquid medium, however, the optimal management of patients with discordant testing is unknown. This study was conducted to evaluate the effect of treatment regimen on treatment outcomes when patients with rifampicin-susceptible pulmonary tuberculosis have isoniazid resistance (INH-R) in liquid medium but isoniazid susceptibility (INH-S) on solid medium.

METHOD

This study was retrospectively conducted by reviewing patient medical records on the liquid compared to solid culture based phenotypic testing at Samsung Medical Center between January 2009 and December 2015. The study population which have INH-R in liquid medium and INH-S on solid medium was divided into two groups: group A (n = 30), which included patients treated for INH-S tuberculosis by discontinuing pyrazinamide (and ethambutol), and group B (n = 56), which included patients treated for INH-R tuberculosis by continuing pyrazinamide and/or adding fluoroquinolone. Unfavorable outcomes included treatment failure and relapse.

RESULTS

There were no statistically significant differences between the two groups including demographic data, comorbidities, radiologic data, and treatment duration. However, baseline smear positive rates were more frequent in group A (19/30, 63.3%) than in group B (22/56, 39.3%; P = 0.033). Only three patients had unfavorable outcomes; one was bacteriologically proven treatment failure and the other two were clinically judged as unfavorable outcomes. All of them were in the group A (3/30, 10%); no unfavorable outcomes occurred in the group B (0/56, 0%; P = 0.040).

CONCLUSIONS

Unfavorable outcomes were less frequent in the group B than in the group A, indicating that treatment regimen modification according to DST results on liquid medium could improve treatment outcomes in patients with rifampicin-susceptible pulmonary tuberculosis. Further studies are required to confirm these findings to overcome the small number of unfavorable outcomes.

The volatile molecule signature of four mycobacteria species

Mycobacteria are the leading cause of death from infectious disease worldwide and limitations in current diagnostics are hampering control efforts. In recent years, the use of small volatile molecules as diagnostic biomarkers for mycobacteria has shown promise for use in the rapid analysis of in vitro cultures as well as ex vivo diagnosis using breath or sputum. In this study, 18 strains from four mycobacteria species (Mycobacterium avium, M. bovis BCG, M. intracellulare and M. xenopi) were analyzed for the first time using two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS). This study represents the first time volatile molecules associated with M. intracellulare and M. xenopi have ever been reported. A total of 217 chromatographic features were identified and 58 features were selected that discriminate between these four species. Putative identifications are provided for 17 of the 58 discriminatory features, three of which have been reported previously in mycobacteria. The identification of mycobacteria-associated volatile biomarker suites could reduce the time-to-diagnosis for mycobacterial infections, either from in vitro cultures prior to the visualization of colonies or directly from ex vivo specimens, thereby shortening the empiric treatment window and potentially improving outcomes.