A study on pattern of resistance to second line anti tubercular drugs among multi drug resistant tuberculosis patients

Pattern of Drug Resistance in Primary Spinal Tuberculosis: A Single-Center Study From India

STUDY DESIGN

Retrospective observational analysis.

OBJECTIVES

Spinal tuberculosis accounts for about 50% of cases among extra pulmonary osteoarticular tuberculosis. Resistance to drugs in spinal tuberculosis patients is on a rise and there is inadequate literature concentrating on the precise pattern of resistance in Indian subcontinent which harbors 24% of global prevalence. The aim was to study the pattern of drug resistance in spinal tuberculosis among first- and second-line drugs. Drug resistance is common in spinal tuberculosis and we intended to find the prevalence of various drug resistance patterns.

METHODS

Patients with spinal tuberculosis visiting a tertiary center were assessed. Samples were taken from the affected vertebrae and sent for BACTEC mycobacterium growth indicator tube (MGIT) 960 culture. Patients with a positive growth in MGIT were included in the study. All previously treated patients (relapse, treatment after failure, treatment after loss to follow-up and other previously treated patients) were excluded.

RESULTS

A total of 150 patients with a positive growth in MGIT report were included in the study, of whom 43 patients had some kind of drug resistance. Seven were multidrug resistant (MDR), 9 had preextensive drug resistance (pre-XDR), and 4 had extensive drug resistance (XDR). Seventeen patients had mono-drug resistance, which was most frequently for isoniazid. Resistance among second-line drugs was common in the fluoroquinolone group.

CONCLUSION

Drug resistance in spinal tuberculosis was found to be 28.6%. Of these, MDR was in 16.2%, pre-XDR in 20.9%, and XDR in 9.3% patients.

Second-line Drug Resistance Characterization in Mycobacterium tuberculosis by Genotype MTBDRsl Assay

Tuberculosis (TB) remains a main hurdle for national programs due to increase in drug resistance to antitubercular drugs. World Health Organization (WHO)-endorsed Line Probe Assay, Genotype MTBDRsl Ver 2.0, gives opportunity for rapid diagnosis and molecular characterization of different mutations in drug targets of fluoroquinolone (FQ) and second-line injectable drugs (SLID). We, retrospectively, analyzed the data of Genotype MTBDRsl Ver 2.0 from January 2018 to June 2018. A total of 863 isolates of Mycobacterium tuberculosis, 687 rifampicin resistant and 176 isoniazid resistant only, were screened for drug resistance in FQ and SLID. All the isolates were tested for Genotype MTBDRsl Ver 2.0 according to the manufacturer’s instructions. The FQ and SLID resistance were detected in 295 (34.2%) and 70 (8.1%) isolates, respectively. Among newly diagnosed and follow-up rifampicin-resistant TB (RR TB) patients, the FQ resistance was 25.8% and 44.5%, respectively. The most common mutation (42.7%) in FQ-resistant isolates was MUT3C in gyrA gene. Both SLID and FQ resistance were detected in 59 (6.8%) RR TB isolates. The mono SLID resistance was detected in 12 (1.7%) isolates of RR TB. Genotype MTBDRsl Ver 2.0 assay is a rapid and important tool for the diagnosis and molecular characterization of second-line drug resistance under programmatic conditions.

Fluoroquinolone resistance and mutational profile of gyrA in pulmonary MDR tuberculosis patients

BACKGROUND

Fluoroquinolones (FQs) are potential drugs that inhibit DNA synthesis and are used in the treatment of multidrug-resistant tuberculosis (TB) and short-term anti-TB regimens. In recent years, a high proportion of FQ resistance has been observed in Mycobacterium tuberculosis isolates. The development of FQ resistance in multidrug-resistant TB negatively impacts patient treatment outcome and is a serious threat to control of TB.

METHODS

The study included a total of 562 samples from patients with pulmonary TB that had been on anti-tuberculosis therapy. MTBDRsl assays were performed for the molecular detection of mutations. Sequence analysis was performed for the characterization and mutational profiling of FQ-resistant isolates.

RESULTS

FQ resistance was observed in 104 samples (18.5%), most of which were previously treated and treatment failure cases. A total of 102 isolates had mutations in DNA gyrase subunit A (gyrA), while mutations in gyrB were observed in only two isolates. Mutational analysis revealed that the mutations mostly alter codons 94 (replacing aspartic acid with glycine, D94G) and 90 (replacing alanine with valine, A90V). In MDR and treatment failure cases, resistance to FQs was most commonly associated with the D94G mutation. In contract, a high proportion of A90V mutations were observed in isolates that were newly diagnosed.

CONCLUSION

The findings suggest that genotypic assays for FQ resistance should be carried out at the time of initial diagnosis, before starting treatment, in order to rule out mutations that impact the potential use of FQs in treatment and to control drug resistance.

Morbidity Trends and Risk of Tuberculosis: Mexico 2007-2017

Background

To know the current status of the epidemiological and geographic distribution of tuberculosis and its complication meningeal tuberculosis in Mexico, this work analyzes national surveillance data (ten years) issued by the General Directorate of Epidemiology (GDE).

Methods

An observational and retrospective analysis of monthly and annual reports of pulmonary and meningeal tuberculosis cases from January 2007 to December 2017 was performed on the annual reports issued by the GDE in Mexico. The number of cases and incidence were classified by year, state, age group, gender, and seasons.

Results

A national case distribution map of pulmonary and meningeal tuberculosis incidence was generated. During this period, a total of 184,003 and 3,388 cases were reported with a median of 16,727.5 and 308 cases per year for pulmonary and meningeal tuberculosis diseases, respectively. The number of cases and incidence of pulmonary and meningeal tuberculosis per year showed that male gender presented a continuous increase in both parameters. The geographic analysis of the distribution of cases of tuberculosis showed that states like Guerrero, Tabasco, and Veracruz presented higher means of tuberculosis cases during this period. Northern states had the highest number of cases in the country compared to other states. In Mexico, pulmonary tuberculosis and meningeal tuberculosis are seasonal. Interestingly, cases of meningeal tuberculosis show an increase during October and November (autumn).

Conclusions

In Mexico, during the years 2007-2017, there has been an increase in the proportion of male TB patients. It remains necessary to implement strategies to detect TB in the adult population, especially among men, because tuberculosis could be difficult to recognize in an early stage in the population, and the appearance of resistant strains can cause an increase in the incidence of the disease.