Extrapulmonary Samples Research Articles

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

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 firstline 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.

Comparative analysis of CBNAAT (GeneXpert) and Ziehl-Nielsen staining test as diagnostic modalities of tuberculosis.

As centuries and millennia passed, tuberculosis remains the major health threat for millions of people. Due to this resurgence of tuberculosis, scientists around the globe have intensified their research efforts to curb down the transmission of this disease and that is the reason which led to the development of new and efficient diagnostic tools, one such being the rapid cartridge-based nucleic acid amplification test which can give the real-time results and that too in a short period of time. These diagnostic tools which are based on the latest technologies help in paving the way to eliminate tuberculosis by early detection method and further prevent the transmission. In this study, we did a comparative analysis of the effectiveness of CBNAAT technique in the early detection of Mycobacterium tuberculosis over the conventional method of Ziehl-Nielsen microscopy as diagnostic modalities. Comparative analysis of CBNAAT (GeneXpert) and Ziehl-Nielsen staining test was done as diagnostic modalities using standard protocols. Out of total 300 samples, 153 were female, 146 were male, while one was transgender. For all these samples, the positivity rates were 48% for the CBNAAT technique and 21.3% for ZN staining method, respectively. For extrapulmonary samples, positivity rates were 49.1% and 11.86% for CBNAAT and ZN microscopy, respectively, while the same for pulmonary samples was 47.7% and 23.6%, respectively. ZN microscopy and CBNAAT are both initial tests for the detection of Mycobacterium tuberculosis, but the introduction of CBNAAT is a boon for peripheral sites. The higher positivity rate of CBNAAT over ZN staining is the icing on the cake with the ability to detect even those cases that could be missed by the latter.

Tuberculosis Diagnosis and Detection of Drug Resistance: A Comprehensive Updated Review

Tuberculosis (TB) is a significant public health challenge, especially in developing nations. Developing a TB eradication strategy is hampered by the global health concern of drug-resistant (DR) TB. Effective patient treatment, preventing TB transfer and avoiding the upsurge of DR strains depend primarily on the timely and accurate identification of DR TB. Due to inadequate sensitivity, the necessity of trained laboratory personnel, the sluggish growth pattern of Mycobacterium bacilli in culture, and the small number of bacilli that are usually found in extrapulmonary TB samples, TB diagnosis is still tricky in clinical practice. Although mycobacterial culture is the gold standard to identify TB and determine drug resistance, it takes 2 to 8 weeks to develop. Despite their high cost, nucleic acid amplification tests (NAATs) and whole-genome sequencing (WGS) are the commonly employed molecular-based methods for diagnosing and identifying TB. The WHO suggested the GeneXpert MTB/RIF to identify TB and detect resistance to rifampicin. In comparison, numerous molecular techniques were developed, including allele-specific PCR (MAS-PCR), solid-phase hybridization, real-time PCR (RT-PCR) and droplet digital PCR-based technique (DDPCR). This manuscript is intended to overview the current approaches for the phenotypic and genotypic diagnosis of TB disease and identifying resistance to antitubercular drugs depending on recently published articles, WHO and CDC reports, and commercially available diagnostic tools.

Xpert MTB/RIF assay among the extra-pulmonary and non-sputum respiratory samples: One year experience at National Tuberculosis Reference Laboratory, Bangladesh

Background: Extra-pulmonary tuberculosis (EPTB) is a diagnostic and therapeutic challenge due to the paucity of suitable rapid diagnostic tools. Objectives: The aim was to assess the frequency of detection of Mycobacterium tuberculosis using Xpert MTB /RIF assay among the extra-pulmonary and non-sputum respiratory samples (NSRS) along with demographic profile, life style variables and proportion of Rifampicin resistant TB among those specimens. Methodology: This cross-sectional retrospective study was conducted at National Tuberculosis Reference Laboratory (NTRL) from January 2018 to December 2018 for period of 1 year. Total 3918 extra-pulmonary and non-sputum respiratory samples from suspected TB patients were enrolled. Detection of Mycobacterium tuberculosis and Rifampicin resistance was performed by Xpert MTB /RIF assay and culture in both liquid and solid media. Results: Among 3918 samples, 3152 were new cases and 766 were previously treated TB cases. A total of 853 (21.77%) MTB were detected by Xpert MTB /RIF assay. Among them, 713 (83.59%) were extra-pulmonary and 140 (16.41%) were non-sputum respiratory samples. Lymph node (LN) aspirates and tissues were the most frequent (37.9 and 9.9%) samples of EPTB. The proportion of RR cases among EPTB was 2.8% and 6.3% among new and previously treated cases. And 2.6% and 11.1% among NSRS new and previously treated cases respectively. Conclusion: This study will give an insight of EPTB and NSRS profile with a view to diagnostic and therapeutic approach in Bangladesh. Bangladesh Journal of Medical Microbiology, January 2023;17(1):21-28

Diagnostic Efficacy of New Xpert Ultra for Extrapulmonary Tuberculosis Using Culture and Composite Reference Standard.

Xpert Ultra (Cepheid, USA) is recently introduced with an extra category of trace-positive results and higher sensitivity for tuberculosis (TB) diagnosis. The objective of the study was to assess the diagnostic accuracy of Xpert Ultra for extrapulmonary samples using culture and composite reference standard (CRS) as the gold standard. In a 1-year (March 2021-22) prospective observational study, samples of suspected extrapulmonary TB (EPTB) patients were subjected to Ziehl-Neelsen staining, culture, and Xpert Ultra (Cepheid, Sunnyvale, CA) tests. Relevant clinical and treatment information was noted. The diagnostic accuracy of Xpert Ultra compared with culture and CRS was calculated. Out of 1720 suspected patients of EPTB, 223 (13%), predominantly males 135 (60%), with a mean age of 41.46 ± 19.81 years, were diagnosed as TB positive following CRS criteria. The maximum cases were of pleural TB (35.4%), followed by central nervous system TB (17.9%), gastrointestinal TB (17.5%), and lymph node TB (12.1%). Of all samples, 150 (8.7%) were microbiologically confirmed, including 141 detected by Xpert ultra, 67 culture positive, and only 16 smear positive. Among the Xpert Ultra-positive samples, 35 showed trace results, including six false-positive results. Considering culture and CRS as the gold standard, the sensitivity (86.57%, 59.64%) and specificity (94.98%, 99.47%) of Xpert Ultra were calculated, respectively. Rifampicin resistance was detected in 1 (0.70%) sample. Diagnosis of EPTB is a challenge and Xpert Ultra may detect TB at a very early stage. However, it is essential to rule out false-positive results. Additional studies are needed on Xpert Ultra to interpret trace results better.

Assessment of Conventional and Molecular Methods in the Routine Management of Tuberculosis in a High Tuberculosis Burden Setting

Background and aims: India is a high-burden tuberculosis region and a drug-resistance hotspot. Despite numerous reports of pulmonary tuberculosis (PTB) cases, there needs to be more literature available on the importance of diagnostic methods in the case of extrapulmonary tuberculosis (EPTB). A prospective study was carried out from July 2017 to June 2018 to compare the efficacy of conventional and molecular methods in detecting PTB and EPTB cases. Methods: 1000 presumptive PTB and 412 EPTB cases were subjected to staining (Ziehl-Neelson and fluorescent staining), culture, GeneXpert, and line probe assay. Results: The sensitivity, specificity, and strength of association, i.e., kappa (k) value of LED-FM, ZN, and GeneXpert, were calculated using standard formulae using solid culture as the gold standard. The sensitivity of GeneXpert in smear-positive/culture-positive PTB was comparable with the smear-negative/culture-positive PTB cases (95.7% Vs. 87.5%) with an overall sensitivity and specificity of 90.5% and 90.1% in EPTB cases, respectively. However, sensitivity was lower for pleural fluid (75%) and tissues (85.7%). In pulmonary instances, 10% (6.7% RIF + INH resistant and 3.3%INH monoresistant) drug resistance was observed, and no drug resistance was found in extra-pulmonary samples. Conclusion: Among conventional methods, Fluorescent staining is more sensitive than Ziehl-Neelson (ZN) staining, while the sensitivity of GeneXpert varies w.r.t type of sample using culture positivity as the gold standard. The present study suggests the promotion of universal DST for all individuals with TB to control drug-resistant tuberculosis.

A-288 Molecular Detection of Mycobacterium tuberculosis in Pulmonary and Extra-Pulmonary Samples. Data from a Brazilian Clinical Laboratory

Abstract Background Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is among the leading infectious causes of death in developing countries. In humans, TB presents as a progressive granulomatous infectious disease that affects lungs causing pulmonary tuberculosis, but can also affect intestines, meninges, bones, joints, lymph nodes, skin and other body tissues causing extra-pulmonary tuberculosis. The aim of this study was to evaluate the frequency of tuberculosis cases detected during the COVID-19 period and the emergence of cases with extrapulmonary diagnosis. Methods This study was a retrospective analysis from January 2017 to December 2022 based on the analysis of 3105 clinical samples processed by the molecular biology section of AFIP Laboratory. All clinical samples were isolated from pulmonary and extra-pulmonary sites recovered from inpatients admitted in several Brazilian tertiary hospitals. In Brief, the DNA extraction was performed according to the type of patient’s samples and, then submitted to Real-Time PCR (qPCR) method using a commercial kit, which contains specific primers and probes to the M. tuberculosis genome. Results Of the 3105 samples tested, 222 (14%) samples were positive for the presence of M. tuberculosis. Out of which, 120/1405 (8,5%) were detected in the pre-Covid-19 period (2017–2019) and 102/1700 (6%) were detected in Covid-19 period (2020–2022). The prevalence of M. tuberculosis infection was 64.5% and 35.5% among men and females, respectively. The main age range was 41 to 50 years (44.7%), while over 60 years comprised 13.5% of cases (Fig. 1). Between the isolate sites, 67.1% of the M. tuberculosis cases were detected in pulmonary and 32.8% in extra-pulmonary body sites, of which, cerebrospinal fluid and blood are among the most frequent, followed by cervical lymph node, ascitic fluid, gastric lavage, urine and others. A total of 95% of M. tuberculosis was detected in patients assisted by public health service. We did not have access to patient’s symptoms, clinical history or further diagnostic procedures. Conclusion Comparing the two periods of the study, a reduction in the positivity rate of new cases was observed in the pandemic period, perhaps this fact can be associated with restrictions on access to the diagnosis of other pathologies in the pandemic period. Despite no information about the severity of the infection, male gender prevalence and age range from 41 to 50 years group need further attention.

Usefulness of truenat-derived DNA from extrapulmonary specimens in direct detection of drug resistant tuberculosis by line probe assay

Objectives: Isoniazid (INH) and second-line drug resistance (DR) detection through line probe assay (LPA) takes long in extrapulmonary (EP) specimens because culture growth needs to be obtained to perform deoxyribonucleic acid (DNA) extraction due to the paucibacillary nature of these specimens. Knowing the DR pattern at the earliest is key to success of the treatment. Delay in appropriate tuberculosis (TB) treatment in EP TB patients runs the risk of DR amplification, significant disease damage, and patient loss to follow-up. Here, LPA was attempted on truenat-derived DNA elute from EP specimens, which, in routine, is discarded after the truenat test, to determine drug sensitivity test (DST) for INH and, where necessary, for second-line drugs (Fluoroquinolones, Kanamycin, amikacin, and capreomycin). Material and Methods: Truenat, acid-fast bacilli culture, and fluorescent microscopy were performed on all EP samples that were received at the laboratory during June–September 2022. DNA elute that was left over from 59 truenat Mycobacterium tuberculosis (MTB) positive EP samples were subjected to Genotype MTBDR plus Ver 2.0 assay. Results: MTBDR plus assay (DNA elute) detected MTB and rifampicin (RIF) and INH DST in 47 samples (79.6%) having truenat MTB count of 7.8 × 102 colony-forming unit/milliliter and above. It also detected RIF DST in 65.2% truenat RIF indeterminate samples and DST for both RIF and INH in 60% of culture negative EP specimens. DST results by LPA (DNA elute) completely concorded with standard indirect LPA (on 21 culture isolates from smear-negative specimens). The MTBDRsl yield was however relatively low (11.1%), although second line LPA (SLLPA) was performed only on 9 first-line DR samples. Conclusions: Left-over truenat-derived DNA elute is a significant sample by-product that can significantly speed up and increase the yield of determination of MTB DST in EP samples for RIF and INH, the most critical drugs for TB treatment.

Detection of Mycobacterium tuberculosis in Pulmonary and Extrapulmonary Samples Using Different Methods: Experience of a Tertiary Care Center in North India

Detection of Mycobacterium tuberculosis in Pulmonary and Extrapulmonary Samples Using Different Methods: Experience of a Tertiary Care Center in North India

Pattern and characteristics of mutations conferring resistance to second line drugs in Mycobacterium tuberculosis isolates of pulmonary and extrapulmonary TB samples

Background & objectivesThe purpose of present study is to analyse the distribution and pattern of genetic mutations in PRE-XDR-TB and extensive drug resistant Mycobacterium tuberculosis (XDR-TB) using second-line line probe assay and to compare them with different parameters. MethodSputum, Lymph node aspirate and cold accesses from patients with rifampicin resistant Tuberculosis were subjected to first line and second line Probe Assay (Genotype MTBDRsl by Hain Life Science, Germany) to assess additional drug resistance to fluroquinolones (Levofloxacin & Moxifloxacin) and Aminoglycosides (Amikacin, Ofloxacin and Kanamycin). The genetic mutation pattern was analysed and compared with demographic, clinical and other parameters. ResultsThe final study population included 123 fluoroquinolone resistant isolates including 14 isolates with additional second line aminoglycosides drug resistance. The most frequent mutation observed among Gyr A drug resistance mutation was D94G (Gyr A MUT3C, 50/123,40%) corresponding to high level resistance to levofloxacin and moxifloxacin. The most frequent wild type mutant among Gyr A gene locus was WT 3 (85/123,69%). The most common mutation among second line aminoglycoside resistant isolates was at eis WT2 (7/14,50%) followed by rrs MUT 2 (4/14,29%). ConclusionsGyrA MUT3C (Asp94Gly) was the most common mutation in Gyr A gene locus in M. tuberculosis causing high level levofloxacin and moxifloxacin resistance. Patients with Asp94Gly mutation was significantly associated with underweight body mass index (p = 0.026). This study also observed that history of anti-tuberculosis therapy is a risk factor for FQ drug resistance mutations (p < 0.001).

Molecular identification of non-tuberculous mycobacterial species isolated from extrapulmonary samples using real-time PCR and rpoB sequence analysis

Tuberculosis (TB) is one of the leading causes of mortality among infectious diseases and accounts for a serious health hazard wordwide. Apart from TB, the members of non-tuberculous mycobacteria (NTM), which includes around 170 species, may also cause different diseases in humans. Therefore this study aimed to investigate the distribution of NTM strains isolated from extrapulmonary (EP) samples by Real-Time PCR and PCR-sequencing methods in Southwest Iran. Three hundred and twenty-five suspected EP samples were collected from patients referred to the referral hospitals in Ahvaz, Iran. The isolates were initially screened by acid fast staining and identified by phenotypic culture and biochemical tests. The Real-Time PCR and rpoB- based PCR methods were performed followed by sequence analysis of rpoB gene. From 124 samples, 77 (62%) were positive for NTM by culture and rpoB sequence analysis. M. fortuitum was the most commonly isolated NTM in present study. In Real-Time PCR, only 69 (55.64%) isolates showed more homology with standard NTM isolates. In general, the growing trend of EPNTM infections in Iran needs specific programs and resources to get a better diagnosis. PCR sequencing is a reliable method, it can be used for definitive identification of positive cultures for identification of NTM species.

Evaluation of Xpert MTB/RIF Ultra assay for detection of Mycobacterium tuberculosis and rifampicin resistance

Tuberculosis (TB) is a public health challenge globally, and molecular testing is recommended to expedite diagnosis. Concerns that Xpert MTB/RIF assay (Xpert) may be less sensitive when testing paucibacillary samples led to the development of the Xpert MTB/RIF Ultra assay (Ultra). We evaluated the performance of Ultra against Xpert on clinical samples sent to the national reference laboratory in Singapore. In total, 149 samples collected between January 2019 and November 2020 were analysed. Mycobacterium tuberculosis complex (MTBC) was isolated from 55 cultures. Using culture as the reference standard, Ultra demonstrated higher sensitivity (96.4% vs 85.5%) and marginally lower specificity (88.3% vs 89.4%) compared to Xpert in the full cohort. When considering only paucibacillary specimens such as extrapulmonary and smear-negative samples, similar results were obtained. Reclassifying Ultra trace results (low levels of MTB are detected but no rifampicin resistant result is detected) as negative in the full cohort led to a decrease in sensitivity by 10.9% and a marginal increase in specificity by 1.1%. In instances of low bacillary load, Ultra also identified rifampicin resistance more accurately than Xpert, when corroborated against other methods such as broth microdilution, line probe assay and whole genome sequencing (WGS). One isolate tested rifampicin-resistant using Xpert and Ultra, but was phenotypically susceptible and WGS demonstrated the presence of the silent mutation Thr444Thr. Ultra is more sensitive than Xpert in the detection of MTBC and rifampicin resistance in our local setting. Nevertheless, the results of molecular testing should still be correlated with phenotypic studies.

Validation of GeneXpert using extrapulmonary samples at the National Tuberculosis Reference Laboratory in Lesotho

Validation of GeneXpert using extrapulmonary samples at the National Tuberculosis Reference Laboratory in Lesotho

An analytic feasibility study of the BD MAX™ MDR-TB assay for testing of non-sputum specimens for detection of the Mycobacterium tuberculosis complex (MTBC) and isoniazid (INH) and rifampin (RIF) resistance

Rapid diagnosis of tuberculosis and drug resistance in extrapulmonary specimens can be challenging. The BD MAX™ multidrug resistant (MDR)-TB assay (BD MAX™) has demonstrated high sensitivity and specificity for the detection of the Mycobacterium tuberculosis complex (MTBC) as well as resistance to INH and Rifampin (RIF) in pulmonary specimens but has not been rigorously assessed in extrapulmonary samples. We evaluated the diagnostic accuracy of the BD MAX™ assay for the detection of MTBC and drug resistance in extrapulmonary specimens spiked with MTBC from the Johns Hopkins strain collection. A total of 1083 tests were performed across multiple sample types, with an overall percent agreement of 94.8% (795/839) for detection of MTBC and 99% (379/383) and 96.4% (323/335) for determination of INH and RIF resistance-conferring mutations, respectively. The BD MAX™ assay provides same day detection of MTBC and drug-resistance results and could be a beneficial diagnostic test in extrapulmonary sample types.

Diagnostic and quantitative performance of the GeneXpert Mycobacterium tuberculosis/resistance to rifampin assay on pulmonary and extrapulmonary tuberculosis samples

INTRODUCTION: No study has simultaneously assessed the diagnostic and quantitative performance of the GeneXpert Mycobacterium tuberculosis/resistance to rifampicin (MTB/RIF) assay on pulmonary and extrapulmonary samples processed in an Indian laboratory. We examined this to assess if GeneXpert can complement existing diagnostic facilities.METHODS: The performance of GeneXpert and acid-fast microscopy were evaluated against culture in 455 pulmonary and 69 extrapulmonary specimens. Their sensitivity, specificity, predictive values and area under the curve (AUC) were estimated. GeneXpert cycle threshold (Ct) cut-offs were also computed to assess their utility in predicting smear positivity and time to culture positivity (TTCP).RESULTS: GeneXpert was significantly more sensitive (100% vs. 84.4%; P < 0.001) and nearly as specific (94.8% vs. 96.7%; P = 0.344), with a greater AUC (0.97 vs. 0.91; P = 0.002) than acid-fast microscopy. It was sensitive and specific for pulmonary (100%; 94.1%) and extrapulmonary (100%; 96.5%) samples, and 100% sensitive for sputum, bronchoalveolar lavage (BAL), lymph node aspirates, pleural fluid, pus and urine. It detected smear-negative specimens with 100% sensitivity. GeneXpert Ct was inversely correlated with sputum smear grading (ρ = −0.66) and positively with TTCP (ρ =0.70). Mean Ct cut-offs of 21.4, 20.1 and 24.6 predicted smear positivity with maximum sensitivity and specificity in sputum, BAL and extrapulmonary samples, respectively. Rifampicin resistance was seen in 17% of samples.CONCLUSIONS: GeneXpert can be a reliable first-line diagnostic for both pulmonary and extrapulmonary samples. It can effectively detect smear-negative and paucibacillary patients, and estimate smear positivity and bacillary burden. This can help Indian laboratories to detect cases early and interrupt community transmission.

Evaluation of the GeneXpert Mycobacterium tuberculosis/Rifampicin Assay for Early Detection of Extrapulmonary Tuberculosis and Rifampicin Resistance in Aligarh Region of Northern India

Purpose: Early diagnosis of extrapulmonary tuberculosis (TB) with simultaneous detection of rifampicin (RIF) resistance (RR) directly from the sample is a revolution brought by GeneXpert Mycobacterium TB (MTB/RIF) assay. Line probe assay (LPA) is not recommended for extrapulmonary/nonsputum specimens; GeneXpert MTB/RIF provides a diagnostic option for these. Hence, the following study aimed to evaluate the performance of GeneXpert MTB/RIF assay in nonsputum samples. Materials and Methods: A total number of 642 extrapulmonary and nonsputum respiratory samples were subjected to Ziehl–Neelsen (ZN) staining technique, fluorescent microscopy (FM), and GeneXpert MTB/RIF Assay. All samples were cultured on a solid Lowenstein–Jensen (LJ) medium and culture-positive samples were subjected to GenoType MTBDRplus LPA and drug susceptibility testing by 1% proportion method on a solid LJ medium. Results: GeneXpert MTB/RIF assay detected MTB in 25.9% (166/642) of the samples. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ZN staining technique and FM were 21.52%, 99.35%, 91.89%, and 78.77% and 27.22%, 99.78%, 97.73%, and 80.07%, respectively. Sensitivity, specificity, PPV, and NPV of GeneXpert MTB/RIF in the detection of MTB were 93.75%, 96.53%, 90.36%, and 97.80%, and RIF RR was 92.0%, 97.74%, 88.46%, and 98.48%, respectively. LPA performed on positive culture growth showed 100% sensitivity and specificity in the detection of RIF and isoniazid resistance. Conclusion: GeneXpert MTB/RIF showed high sensitivity and specificity in detecting MTB and simultaneous RIF RR among the nonsputum samples which had a good concordance to LPA. It provides a judicious option for early detection of multidrug-resistant TB in extrapulmonary and nonsputum respiratory samples.

Abdominal Tuberculosis Presenting as Anemia Refractory to Standard Therapy in an Elderly Male

Abstract India bears a significant proportion of tuberculosis cases, accounting for approximately 28% of the global burden. Among the reported global cases, around 16% constitute extrapulmonary tuberculosis (EPTB). EPTB diagnosis and treatment are usually challenging. The diagnosis frequently requires the application of contemporary methods, such as acquiring extrapulmonary samples and utilizing advanced diagnostic tools that involve immunological and molecular techniques. Here, we present a case of an elderly male who presented with constitutional symptoms and severe anemia which was refractory to standard hematinic and transfusion therapy. The patient was diagnosed to be a case of abdominal tuberculosis and improved with antitubercular therapy.

USE OF GENE XPERT MTB/RIF ASSAY FOR DETECTING MYCOBACTERIUM TUBERCULOSIS AND RIFAMPICIN RESISTANCE

The current study was designed to assess the specificity and sensitivity of MTB/RIF assay for early detection of Mycobacterium tuberculosis and RIF resistance in smear-positive and smear-negative pulmonary and extrapulmonary samples. This retrospective study was conducted in Bakhtawar Amin Trust Hospital Multan from July 2021 to July 2022. Total 240 pulmonary samples (gastric fluid specimens, post-bronchoscopic sputum, bronchoscopic aspirate, bronchoalveolar lavage and sputum) and 170 extra-pulmonary samples (urine specimens, skin biopsy, pericardial fluid, cerebrospinal fluid, ascitic fluid, disc material, lymph node biopsy and pleural fluid) were collected. After culture growth and identification of species, drug susceptibility testing (DST) was done. All samples underwent Xpert MTB/RIF assay. A total of 240 pulmonary and 170 extra-pulmonary samples from 410 patients were collected. The mean age of the patients was 46.5 ± 10 years. Of 410 subjects, 100 had TB, and 310 had no evidence of TB. Of 100 TB patients, the specificity of the MTB/RIF assay was 100 % (100), sensitivity was 69% (69), PPV was 100% (100), and NPV was 91% (91). According to the MTB/RIF assay, 79 samples were RIF-susceptible, and 1 was RIFresistant; DST confirmed the results. MTB/RIF assay is a valuable tool for detecting Mycobacterium tuberculosis and rifampicin resistance. It is not technique sensitive and provides results in less than three hours.

1428. Clinical Characteristics and Management of Nontuberculous Mycobacterial Infections in the Finger Lakes Region of New York

Abstract Background Nontuberculous Mycobacteria (NTM) are ubiquitous in the environment and associated with pulmonary and extra-pulmonary infections. Evaluation and treatment of these infections is complex and prolonged, involving oral, intravenous and inhaled therapies, although not all patients with NTM need treatment. We reviewed the clinical characteristics and referral patterns of NTM patients in our institutions to evaluate resource needs. Methods We retrospectively identified all patients who had NTM isolated from 2 referral labs servicing the Finger Lakes Region of NYS, from April 1, 2018 thru March 31, 2020. Demographic, comorbidities, culture, and treatment data were collected from medical records. We compared comorbidities, clinical symptoms, and species among patients with pulmonary and extra-pulmonary NTM. Pearson’s chi-squared and student t-test were performed where appropriate for statistical analysis. Results 155 NTMs were isolated from 149 patients, 128 from pulmonary and 27 from extra-pulmonary sites. Patients with pulmonary NTM were more likely to be older, female, and have underlying lung disease (Table 1). Patients with extra-pulmonary NTM were more likely to have immunodeficiency. Mycobacterium avium complex (MAC) was isolated more frequently in pulmonary samples and rapidly growing mycobacteria more frequently from extra-pulmonary samples (Table 2). Disease site specific symptoms were more common than constitutional symptoms in both groups. 36% of patients with pulmonary NTM were treated compared with 70% of patients with extra-pulmonary NTM (Table 3). 69% were referred to Pulmonologists, and 43% to infectious diseases for evaluation and management. Table 1Demographics Demographic data for patients with pulmonary and extrapulmonary NTM Table 2Mycobacterium species Mycobacterium species isolated from patients with pulmonary and extrapulmonary NTM Table 3Clinical characteristics Clinical characteristics of patients with pulmonary and extrapulmonary NTM including symptoms, referral to specialists, whether patients were diagnosed with disease by a clinician, and how many were treated. Conclusion Though not all patients with NTM isolated from culture require treatment, most of the patients in our cohort had extensive evaluation, those on treatment required multidisciplinary care, and many not on treatment require ongoing monitoring. Knowing the volume and clinical characteristics of NTM patients in our region has helped to identify the needed resources for developing a comprehensive regional NTM center of Excellence. Other institutions can similarly assess their volume to plan for the increasing incidence of these infections. Disclosures Ghinwa Dumyati, MD, Pfizer: Grant/Research Support.

Utility of anti-Mycobacterium tuberculosis antibody (ab905) for detection of mycobacterial antigens in formalin-fixed paraffin-embedded tissues from clinically and histologically suggestive extrapulmonary tuberculosis cases

BackgroundThe detection of acid-fast bacilli in extrapulmonary tissue samples is challenging due to its paucibacillary nature. The present study assessed the utility of immunohistochemistry (IHC) using anti-Mycobacterium tuberculosis antibody (ab905) for detecting the presence of mycobacterial antigens in archived formalin-fixed paraffin-embedded (FFPE) tissues. MethodsFFPE tissues [surgical biopsies (n = 32) and post-mortem tissues (n = 8)] from clinically and histologically suggestive extrapulmonary tuberculosis (EPTB) cases at the Korle Bu Teaching Hospital, Accra, Ghana from 2015 to 2020 were stained with IHC (anti-Mycobacterium tuberculosis antibody) and Ziehl-Neelsen (ZN) stain. The staining outcomes of IHC and ZN were compared, and their sensitivity and specificity determined against histopathology as reference standard. ResultsLymph nodes were about 40% (16/40) of the samples analyzed. IHC stained positive in 43.8% (7/16) biopsies and 87.5% (4/5) post-mortem samples ranging from 43.8% (7/16) in lymph nodes to 80% (4/5) in gastrointestinal organs. The overall sensitivity for IHC was 52.50% (95% CI: 36.13%–68.49%) and 0% (95% CI: 0.00%–8.81%) for ZN. Specificity was 72.50% (95% CI: 56.11%–85.40%) and 75% (95% CI: 58.80–87.31%) for IHC and ZN respectively. ConclusionsIHC using anti-Mycobacterium tuberculosis antibody (ab905) can detect mycobacterial antigens in diverse range of paucibacillary extrapulmonary tissue sections. It is potentially a useful tool for the diagnosis of EPTB in FFPE tissues in a routine pathology laboratory.