Fast and Accurate Identification of <i>M. tuberculosis</i>Complex Using an Immunochromatographic MPT64 Antigen Detection Test

Background: A new rapid Immunochromatographic test (ICT) kit (MPT64 TB Ag Kit) for detection of MPT64 Antigen in M. tuberculosis (MTB) isolates used for rapid identification of MTB isolates developed by SD (Standard Diagnostics) Bio line, South Korea was evaluated. The ICT is a rapid, reliable and cheaper method that can be used instead of conventional biochemical tests for confirming MTB in culture isolates in resource limited laboratories. The study also evaluated the ability of ICT to detect MPT64-Antigen before the micro MGIT could signal positive. Material/Methods: A total of 450 sputum samples of individual patients were used for the study. 152 isolates of Mycobacteria were recovered from solid and liquid media. These strains were tested for the detection of MPT64-antigen. H37Rv strain was served as the positive reference control and also used for early detection of Antigen experiment. Findings: The development of bands on both test and sample region when H37Rv strain was tested were seen (MPT64 antigen positive). When 138 MTB isolates were tested, it showed a similar banding pattern indicating 100% sensitivity. MPT64 band formation was not detected in any of the 14 isolates indicating 100% specificity. Both PPV & NPV were 100%. All the isolates negative for MPT64 Ag were confirmed as MOTT by conventional bio-chemical PNBA. The H37Rv strain showed a faint band from the 2nd day onwards from inoculation till 3rd day in the earlier Antigen detection experiment. Conclusion: Rapid identification of MTB culture isolate is a pressing need for diagnosis and proceeding to perform drug susceptibility testing. MPT64 TB Ag detection ICT kit is a rapid, reliable method, good substitute for molecular identification methods, and conventional biochemical test which is time-consuming and technically demanding. The early detection of Antigen can be used as an effective tool in diagnosis.

Revisiting Acid-Fast Bacilli Microscopy of Concentrated Sputum Smears as an Efficient Tool for the Diagnosis of Tuberculosis: A Study from a Tertiary Care Centre in Southern India

Background and objectives: With 2.2 million new cases every year, Tuberculosis (TB) continues to be an epidemic of large proportions in India. Conventional direct sputum smear microscopy, though limited in its sensitivity, is still the most common method of testing for TB. Newer techniques such as concentrated sputum microscopy, have shown some promise in improving this limited sensitivity. We have compared the efficacy of concentrated sputum versus the direct smear technique in 1000 sputum samples of patients suspected to be suffering from TB. Methods: A total of 1000 sputum specimens were collected for direct acid-fast bacilli (AFB) smear, concentrated AFB smear and culture from St. John’s Medical College and Hospital. 39 contaminated samples were (3.9%) omitted during the final analysis. Mycobacterial culture was used as the reference standard method for the detection of TB. Results: 184 and 198 of the 961 samples were found to AFB positive by direct smear microscopy and concentrated smear technique respectively. The measured sensitivity and specificity of direct smear microscopy were 69.86% and 95.82%, while that of concentrated smear microscopy was 76.71% and 95.96 % respectively. 33 samples found to be negative by the direct smear method turned out to be positive by the concentrated smear technique. Conclusions: Though our study suggests no significant statistical difference between the two techniques of detecting pulmonary tuberculosis, we recommend the use of the concentrated technique in centres such as ours, where facilities are already in place. In this way, the number of cases of TB that remain untreated may significantly come down.

A Comparative Study of Drug Susceptibility Testing Techniques for Identification of Drug Resistant TB in a Tertiary Care Centre, South India

India tops the global list for Drug resistant Tuberculosis, but inadequate and expensive laboratory culture techniques have led to delay in the diagnosis and treatment. We studied the potential of an alternative method which could be cost-effective by combining the drugs in the same tube for identification of drug resistance. Drug Susceptibility Test (DST) results of 1000 sputum samples are got from suspected TB patients against INH (isoniazid) and Rifampicin by two techniques: a) a modified technique with both drugs in the same MGIT tube and b) a standard technique with the antibiotics in separate MGIT tubes for the diagnosis of MDR-TB (Multidrug Resistant). 39 samples were contaminated and were excluded from final analysis. 198 were smear positives by the concentrated Ziehl-Neelsen’s staining method. 219 were found to be culture positive out of which 195 were identified as M. tuberculosis complex. 40 (20.5%) strains were identified as MDR-TB by the conventional method and 39 were picked up by the modified DST. INH and Rifampicin mono-resistance accounted for 32 (16.4%) and 4 (2%) respectively. 99% concordance was observed between the two tests in categorizing MDR-TB. Similarly modified technique with combination of the second line Antibiotics-Ofloxacin, Kanamycin and Capreomycin was applied on the identified MDR strains in a stepwise manner. 6 (15%) were identified as Pre-XDR strains and 2 (5%) were found to be XDR-TB strains. This study implies that combining drugs in the same tube may be an equivalent and possibly a cost-effective alternative which needs to be explored further.

Nurse Mentor Training Program to Improve Quality of Maternal and Newborn Care at Primary Health Centres: Process Evaluation

Quality of maternal and newborn care could be improved if health care providers’ knowledge and competencies as well as system level constraints are addressed. However, due to several barriers staff nurses who form the frontline of health care workforce have limited access to enhancing their clinical knowledge and competencies. To address this gap, a new cadre of nurse mentors (NMs) for the public health system were trained by specialists from a teaching hospital in a special 5-week training course. This included 54 hours of theory and 110 hours of practical in clinical obstetric and newborn care, apart from mentoring, quality improvement and health systems issues. The nurse mentors were assigned to support staff nurses in the primary health care centres (PHCs) in eight northern Karnataka districts. Each NM covered 6-8 PHCs monthly for 2 - 3 days and thus a total of 385 PHCs were reached. They received support in the field through supportive supervision visits done by the specialists who had trained them, as well as by refresher training and clinical postings to the district hospitals. This paper presents impact of the training program on change in immediate and long term knowledge and competency scores of nurse mentors. Their baseline knowledge scores changed from 44.3 ± 12.7 to 72.1 ± 13.8 immediately after the training in obstetric and from 18.2 ± 19.1 to 66.4 ± 14.9 in newborn (p p p > 0.05). Skills score soon after training increased from 62.2 ± 13.2 to 69.6 ± 12.5 in obstetric after a 1 year period and from 52.6 ± 9.3;63.5 ± 14.4 in newborn (p < 0.001) content areas respectively. These findings have implications for those interested in improving quality of maternal and child care through nurse-dependent health delivery systems.