Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Dr Mohan Z Mani

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On Sep 2018




Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."



Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



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Professor and Head
Department of Pathology
Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
On Sep 2018




Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
‘Knowledge is treasure of a wise man.’ The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
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I wish JCDR a great success and I hope that journal will soar higher with the passing time."



Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




Dr. Arunava Biswas

"My sincere attachment with JCDR as an author as well as reviewer is a learning experience . Their systematic approach in publication of article in various categories is really praiseworthy.
Their prompt and timely response to review's query and the manner in which they have set the reviewing process helps in extracting the best possible scientific writings for publication.
It's a honour and pride to be a part of the JCDR team. My very best wishes to JCDR and hope it will sparkle up above the sky as a high indexed journal in near future."



Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




Dr. C.S. Ramesh Babu
" Journal of Clinical and Diagnostic Research (JCDR) is a multi-specialty medical and dental journal publishing high quality research articles in almost all branches of medicine. The quality of printing of figures and tables is excellent and comparable to any International journal. An added advantage is nominal publication charges and monthly issue of the journal and more chances of an article being accepted for publication. Moreover being a multi-specialty journal an article concerning a particular specialty has a wider reach of readers of other related specialties also. As an author and reviewer for several years I find this Journal most suitable and highly recommend this Journal."
Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."



Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011




Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."



Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011
Anuradha

Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.


Dr. Anuradha
E-mail: anuradha2nittur@gmail.com
On Jan 2020

Important Notice

Original article / research
Year : 2024 | Month : February | Volume : 18 | Issue : 2 | Page : DC11 - DC14 Full Version

Diagnostic Performance and Comparative Analysis of Conventional Drug Susceptibility Testing, Line Probe Assay, and GeneXpert in Extrapulmonary Tuberculosis Cases: A Cross-sectional Observational Study


Published: February 1, 2024 | DOI: https://doi.org/10.7860/JCDR/2024/64599.19095
Ashima Jamwal, Anjali Swami, Ankita Mohanty, Sujata Baveja

1. Senior Resident, Department of Microbiology, Lokmanya Tilak Municipal Medical College, Mumbai, Maharashtra, India. 2. Associate Professor, Department of Microbiology, Lokmanya Tilak Municipal Medical College, Mumbai, Maharashtra, India. 3. Third Year Resident, Department of Microbiology, Lokmanya Tilak Municipal Medical College, Mumbai, Maharashtra, India. 4. Ex-Professor and Head, Department of Microbiology, Lokmanya Tilak Municipal Medical College, Mumbai, Maharashtra, India.

Correspondence Address :
Dr. Anjali Swami,
Associate Professor, Department of Microbiology, LTMMC, Sion, Mumbai-400022, Maharashtra, India.
E-mail: lifez.abt.fun@gmail.com

Abstract

Introduction: Tuberculosis (TB), a known threat to mankind for ages, causes a significant burden on healthcare worldwide. The alarming rise of Extrapulmonary Tuberculosis (EPTB) has led healthcare professionals to opt for molecular diagnostics. Despite the availability of rapid diagnostics, conventional culture Drug Susceptibility Testing (DST) is still considered the gold standard in diagnosing TB.

Aim: To assess the diagnostic accuracy of culture DST which is considered the gold standard.

Materials and Methods: This cross-sectional observational study included 150 suspected EPTB patients and was conducted over a period of one year (September 2018 to August 2019) at Lokmanya Tilak Municipal Medical College and Sion Hospital (LTMMC), a tertiary care hospital in central Mumbai, Maharashtra, India. The hospital is located adjacent to Dharavi, the largest slum area with a high population density, which contributes to the majority of patients attending clinics. Patients attending the pulmonary medicine Outpatient Department (OPD) with extrapulmonary manifestations and suspected cases of EPTB were enrolled in the study. Samples, excluding sputum, were sent to the Department of Microbiology, LTMMC, Sion Hospital for GeneXpert analysis. The samples were further evaluated by microscopy, GeneXpert, and culture DST to detect the presence of Mycobacterium tuberculosis (M. tuberculosis) and drug susceptibility, respectively. Patients positive for Pulmonary Tuberculosis (PTB) were excluded from the study. Categorical variables were described using percentages. A Chi-square test was applied, and a p-value of <0.05 was considered significant. All statistical analyses were performed using SPSS statistical software (IBM SPSS version 26.0, Armonk, N.Y.).

Results: Out of the 150 extrapulmonary samples, 23 (15.33%) samples were culture positive for M. tuberculosis and were subjected to DST using the 1% proportion method and GeneXpert assay. The MDR isolates were tested using the first-line Line Probe Assay (LPA). Eleven (47.8%) showed resistance to first-line antitubercular drugs. Among the 12 new cases, only 2 (16.7%) showed resistance compared to 9 (81.8%) in previously treated cases. A discordance of 8.7% was observed between DST with GeneXpert and LPA. Additionally, a discordance of 8.7% was observed between DST and LPA for rifampicin resistance and 4.3% for isoniazid resistance.

Conclusion: The paucibacillary nature of extrapulmonary samples contributes to the challenging diagnosis of EPTB cases, leading to increased drug resistance. Highlighting the importance of the conventional solid culture DST method, this study strongly recommends the use of conventional DST accompanied by LPA for extrapulmonary cases.

Keywords

Antitubercular drugs, Diagnosis, Drug resistance

Tuberculosis (TB) is a communicable disease caused by the M. tuberculosis complex. Initially affecting the lungs, TB progresses to pulmonary TB (PTB) and extrapulmonary TB (EPTB), characterised by infection in other body organs (1). The infection commonly spreads through small droplet nuclei shed when an infected person coughs or sneezes. EPTB affects organs other than the lungs, with the exception of miliary TB. Diagnosis of EPTB is challenging due to its atypical presentations, often leading to misdiagnosis. It constitutes around 15-20% of all TB cases (2). Conventional diagnostic methods struggle to diagnose EPTB due to the lengthy testing time, sampling difficulty, and the paucibacillary nature of samples (3). Limited information is available regarding drug resistance in EPTB, especially in high-burden countries like India (4), primarily due to the difficulty in obtaining diagnostic specimens and the limited number of national laboratories equipped to conduct culture and DST for M. tuberculosis from extrapulmonary specimens. Clinical symptoms are the main prognostic indicators in EPTB, and suspicion of drug resistance arises only after failure or non response to first-line therapy. Since culture DST evaluation for extrapulmonary samples is rarely presented in published literature, only the advantage of upfront DST by Gene Xpert (5) is highlighted. Therefore, understanding the methodology and purpose of conventional culture DST in the era of molecular diagnostics is crucial. With the rise of drug resistance in TB patients, culture DST holds great value, as the presence of gene mutations may lead to false-negative results in molecular tests like LPA (6) and Gene Xpert. This study aims to assess the diagnostic accuracy of culture DST as the gold standard and to evaluate its performance in comparison with LPA and Gene Xpert for the diagnosis of EPTB. The study addresses the burden of drug resistance in EPTB.

Material and Methods

This cross-sectional observational study, involving 150 suspected EPTB patients, was conducted over one year (September 2018 to August 2019) at Lokmanya Tilak Municipal Medical College and Sion Hospital, a tertiary care hospital in central Mumbai, Maharashtra, India. The study protocol received approval from the Institutional Ethics Committee (IEC) (IEC/LTMMC761/19) with registration number ECR/266/Lokmanya/Inst/MH/2013RR-16. Informed consent was obtained from all enrolled patients, and consent from guardians was secured for patients under 18 years of age.

Inclusion criteria: Patients visiting the outpatient chest and TB department at the centre, as well as those admitted with suspicion of EPTB were included in the study.

Exclusion criteria: Patients who were tested positive for PTB were excluded from the study.

Sample size calculation: The sample size, calculated using the formula for an infinite population, (where the population is greater than 50,000)=Z2×(p)×(1-p)C2 considering a confidence interval of 95% and a margin of error of 6%, and a prevalence percentage of 15-20% for an unlimited population size, was determined to be 144. Rounding off resulted in a sample size of 150 (7).

Study Procedure

A total of 150 extrapulmonary samples, such as pus, urine, Cerebrospinal Fluid (CSF) and tissue biopsy, were received and tested in the Department of Microbiology. Standard microbiological diagnostics, including acid-fast staining microscopy, culture using Lowenstein-Jensen media, and molecular techniques like GeneXpert® Cartridge based Nucleic Acid Amplification Test (CBNAAT) manufactured by Cepheid Diagnostics, were employed. Drug resistance testing for isoniazid and rifampicin was performed using the 1st line LPA (GenoType® M. tuberculosis DRplus VER 2.0). The samples, except for sterile body fluids, were decontaminated using the 2% N-acetyl-l-cysteine–sodium hydroxide (NALC-NaOH) method and cultured on Lowenstein Jensen (LJ) medium. The 23 positive cultures were confirmed using the SD BIOLINE MPT-64 kit (8) for M. tuberculosis and then subjected to 1st line DST using the 1% proportion method, GeneXpert assay, and LPA (1st line), respectively. Ziehl-Neelsen staining (9) was performed for all the samples.

(a) Proportion method of Drug Susceptibility Testing (DST): On LJ medium with drug concentrations as mentioned in (Table/Fig 1), susceptibility testing of culture-positive specimens was conducted. Colonies were removed from the LJ slant and homogenised using glass beads and a vortex mixer in sterile distilled water. The turbidity of each suspension was adjusted to meet the McFarland No. 1 turbidity criterion. Two homogenised bacterial suspension dilutions, 103 and 105, were inoculated on each of the drug-containing media. Additionally, both suspensions were inoculated on a drug-free medium as a positive control. Any isolate showing more than 1% growth on the medium containing the drug, compared to the control, was labeled as a resistant strain. The standard sensitive strain H37Rv was used as a control strain (10).

(b) GeneXpert assay was performed on all considered samples at the centre. The GeneXpert assay for M. tuberculosis works based on the principle of the CBNAAT (11).

(c) Furthermore, the 23 culture-positive isolates underwent 1st line LPA at a referral centre in our city, and the results were obtained. LPAs are a family of DNA strip-based tests that allow users to determine the drug resistance profile of an M. tuberculosis complex strain by interpreting a pattern of bands representing lines of immobilised probes bound (or hybridised) to M. tuberculosis complex amplicons (DNA amplification products) (12).

Important definitions include (13)

• Mono resistance: Resistance to only one first-line antitubercular drug.

• Multidrug Resistance (MDR): Resistance to atleast both isoniazid and rifampicin.

• Polyresistance: Resistance to more than one first-line antitubercular drug, excluding both isoniazid and rifampicin.

Statistical Analysis

Categorical variables were described using percentages. A Chi-square test was applied, and a p-value of <0.05 was considered significant. All statistical analyses were performed using SPSS statistical software (IBM SPSS version 26.0, Armonk, N.Y.).

Results

Out of 150 patients, 25 (16.7%) were culture-positive for tuberculosis. Among these, 23 were positive for M. tuberculosis and 2 were identified as Non Tuberculous Mycobacteria (NTM). The NTM isolates were not further processed, and susceptibility testing was only conducted for the M. tuberculosis isolates.

Patterns of resistance to first-line anti-tubercular drugs among patients: Out of the 150 extrapulmonary samples, 23 (15.33%) were culture-positive for M. tuberculosis and subjected to culture Drug Susceptibility Testing (DST). Among the M. tuberculosis positive patients, 11 (47.8%) showed resistance to first-line antitubercular drugs (Table/Fig 2).

Distribution of M. tuberculosis susceptibility based on treatment history: Among 12 new cases, only 2 (8.7%) showed resistance to Streptomycin, while 9 (39.1%) previously treated cases showed resistance to Rifampicin (3), Isoniazid and Rifampicin (5), and Isoniazid, Ethambutol, and Streptomycin (1) (Table/Fig 3).

Comparing the results of conventional DSTwith Gene Xpert assay and LPA for Rifampicin susceptibility: Among the 23 isolates, DST showed eight with rifampicin resistance, while both Gene Xpert and LPA identified 10 with rifampicin resistance, resulting in an 8.7% discordance between DST and both Gene Xpert and LPA (Table/Fig 4).

Comparing the results of conventional DSTwith LPA for mono or MDR analysis: DST showed eight isolates with rifampicin resistance and five with isoniazid resistance, while LPA identified 10 with rifampicin resistance and four with isoniazid resistance, resulting in a discordance of 8.7% for rifampicin resistance and 4.3% for isoniazid resistance (Table/Fig 5).

Comparing the smear and culture positivity in extrapulmonary samples: A comparison between primary smear and culture results of M. tuberculosis among patients showed a sensitivity of 48% and specificity of 96% for Ziehl-Neelsen (ZN) staining (Table/Fig 6).

Discussion

India is a major contributor to the global burden of TB, with cities like Mumbai facing challenges due to high population density, low living standards, and poor sanitation, which contribute to the increasing number of extrapulmonary cases (14). The sensitivity of Ziehl-Neelsen (ZN) staining was observed to be 48%, with a specificity of 96%. In a study by Ozkutuk N and Surucüoglu S the sensitivity and specificity of microscopic examination for extrapulmonary specimens were reported as 47.8% and 99%, respectively (15). The variation in sensitivity could be attributed to the paucibacillary nature of extrapulmonary specimens and nonuniform distribution of bacilli within them. Furthermore, the higher smear positivity compared to culture positivity in present study may be attributed to interobserver variations in reporting microscopy findings. In present study, 23 (15.33%) samples were culture-positive for M. tuberculosis , and among them, 11 (47.8%) showed resistance to first-line antitubercular drugs. This culture positivity rate was consistent with the findings of a study by Dusthackeer A et al., which reported a culture positivity rate of 15.5% for extrapulmonary samples (14).

The majority of previously treated cases in present study showed acquired drug resistance, aligning with the research conducted by Maurya AK et al., in northern India, where patients with EPTB had an overall MDR TB rate of 13.4% (16). In present study, MDR-TB was demonstrated in 21.7% of cases, indicating a potential sampling bias due to a majority of the samples being obtained from chronic TB sufferers. This finding contrasts with the study by Goyal V et al., which inferred an MDR-TB rate of 39.9% in Western states 13of India (17). A discordance of two isolates (8.7%) was observed between DST, Gene Xpert, and LPA. These results, while statistically insignificant, are likely due to the small sample size and may not be applicable for a larger population. Similarly, in a study by Vadwai V et al., the Gene Xpert test correctly identified 98% of phenotypic rifampicin-resistant cases and 94% of phenotypic rifampicin-susceptible cases (18). A discrepancy of six samples was observed between Gene Xpert and DST results. A 100% concordance was observed between Gene Xpert and LPA regarding the detection of rifampicin monoresistance. However, in a study by Yadav RN et al., the sensitivity of the Xpert M. tuberculosis /RIF assay and LPA were found to be 96% and 99%, respectively (19), indicating potential variations based on sampling regions, sampling approaches, and rpoB gene mutations among populations.

In the current study, only one sample was identified as isoniazid-resistant by conventional DST but was detected as susceptible by LPA. LPA (M. tuberculosis DRplus) detects low-level isoniazid resistance, including Inh A and katG probes for determining high-level isoniazid resistance. The discordant result might be explained by mutations, such as oxyR-ahpC and kasA genes, which are not detected by the LPA. Additionally, the detection limit of LPA is 10,000 colony-forming units per milliliter (CFU/mL), whereas culture has a detection limit of 10-100 CFU/mL (20),(21). Similarly, a study by Saglik I et al., noted lower sensitivity for the detection of isoniazid resistance with the M. tuberculosis DR assay (22).

Limitation(s)

The study had several major limitations. Firstly, the sample size was not large enough to cover the variety of strains exhibiting mutations. Secondly, the results of specificity and sensitivity of tests like LPA, DST, and Gene Xpert cannot be directly applied to a larger population. Despite these limitations, this study holds great relevance for readers. Limited data is available on drug resistance detection in EPTB compared to pulmonary TB in the Indian context. The study highlights the importance of targeting treatment based on the resistance profiles of patients, rather than blindly prescribing medication due to the lack of DST facilities in rural areas. This approach may contribute to tackling the increasing burden of drug-resistant TB. The results may not be extrapolated to a larger population which may be considered one of the limitations of this study.

Conclusion

Although DST by the conventional culture method has the disadvantage of taking several weeks (28 days for culture and 42 days for DST), its importance cannot be ignored. This is especially true when Gene Xpert shows false-positive results due to patients being on treatment, experiencing relapse, or undergoing treatment after being lost to follow-up. Screening patients on a routine basis using Gene Xpert in such cases can misguide clinicians about the patient’s response to treatment. Culture holds importance in cases where LPA fails to detect mutations other than rpoB, InhA, and Kat G. Therefore, the present study asserts that the conventional DST method remains the gold standard for diagnosing EPTB.

Acknowledgement

The authors would like to express their gratitude to the RNTCP team for their constant support and guidance.

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DOI and Others

DOI: 10.7860/JCDR/2024/64599.19095

Date of Submission: Apr 09, 2023
Date of Peer Review: Jul 14, 2023
Date of Acceptance: Dec 07, 2023
Date of Publishing: Feb 01, 2024

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. NA

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Apr 11, 2023
• Manual Googling: Dec 02, 2023
• iThenticate Software: Dec 05, 2025 (8%)

ETYMOLOGY: Author Origin

EMENDATIONS: 7

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