Diagnosis of extrapulmonary tuberculosis by smear, culture, and PCR using universal sample processing technology

Clinicopathological Profile in Patients with Tubercular Cervical Lymphadenitis and Its Treatment Outcome

Tuberculosis is a common occurrence in developing countries. Drug resistance, co-morbidities, and limited availability of new rapid tests such as the GeneXpert/MTB Rif assay make diagnosis and treatment of extrapulmonary tuberculosis burdensome. A cross-sectional study was carried out at Employees' State Insurance Corporation Medical College and Hospital, Faridabad, Haryana of patients treated for tubercular cervical lymphadenopathy from December 2021 to March 2023 in the department of ENT. This study included 58 patients. The clinicopathological profile of patients and the outcome of treatment with antitubercular therapy were noted. The majority of patients had level V (39.6%) involvement. Incidental diagnosis of diabetes mellitus was seen in 2 cases (3.4%). Fever was the commonest constitutional symptom observed in 27.5% of cases. FNAC was suggestive of tubercular abscess in 48.2% and the GeneXpert MTB/RIF assay detected Mycobacterial tuberculosis in all the cases with rifampicin resistance in only one case. 56 cases (96.5%) had complete resolution after completion of antitubercular therapy including patients with rifampicin resistance and patients with diabetes mellitus. In the remaining two cases, treatment was prolonged for a few months before the resolution of the disease was observed. Timely diagnosis, patient compliance to antitubercular therapy, and adequate management of comorbidities lead to successful treatment outcomes in tubercular cervical lymphadenitis. Delayed response to treatment in a few cases needs further research into factors like immune status, nutrition, living conditions, and quality of drugs available to the public.

Diagnostic accuracy of GeneXpert in the diagnosis of spinal tuberculosis: A systematic review and meta-analysis

Tuberculosis remains a significant global health issue, with spinal tuberculosis being a severe form of extrapulmonary tuberculosis. Despite the high morbidity associated with spinal tuberculosis, effective and rapid diagnostic methods are limited. The aim of this study was to evaluate the diagnostic accuracy of the GeneXpert compared to other microbiological methods in diagnosing spinal tuberculosis. A systematic review and meta-analysis were conducted following the PRISMA guidelines. Six databases (PubMed, Scopus, EBSCO, EMBASE, ScienceDirect, and Cochrane Central) were searched for relevant studies as of August 31, 2023. Studies were selected based on predefined inclusion criteria, focusing on patients diagnosed with spinal tuberculosis and comparing GeneXpert to microbiological culture, acid-fast bacilli (AFB) staining, and polymerase chain reaction (PCR). Two authors independently performed data extraction and quality assessment, and the meta-analysis was conducted using Meta-DiSc 2.0. Fourteen studies comprising retrospective cohort, prospective cohort, and cross-sectional designs were included. GeneXpert demonstrated a pooled sensitivity of 92% (85-96%) and specificity of 71% (51-86%) compared to culture. AFB smear had the highest specificity at 80% (70- 88%) but the lowest sensitivity at 27% (20-35%). The PCR had sensitivity and specificity of 83% (67-92%) and 58% (31-81%), respectively. Substantial heterogeneity was noted across the studies. This study highlighted that GeneXpert had high sensitivity and moderate specificity in diagnosing spinal tuberculosis, making it an alternative to conventional methods. However, further validation through larger, interventional studies is necessary to standardize its use in clinical practice.

Nanopore-based targeted next-generation sequencing of tissue samples for tuberculosis diagnosis

Objective

Diagnosing tuberculosis (TB) can be particularly challenging in the absence of sputum for pulmonary tuberculosis cases and extrapulmonary TB (EPTB). This study evaluated the utility of nanopore-based targeted next-generation sequencing (tNGS) for diagnosing TB in tissue samples, and compared its efficacy with other established diagnostic methods.

Methods

A total of 110 tissue samples from clinical cases were examined. The sensitivity and specificity of tNGS were benchmarked against a range of existing diagnostic approaches including hematoxylin and eosin (HE) staining in conjunction with acid-fast bacilli (AFB) detection, HE staining combined with PCR, HE staining paired with immunohistochemistry (IHC) using anti-MPT64, and the Xpert Mycobacterium tuberculosis (MTB)/rifampicin (RIF) assay.

Results

The sensitivity and specificity of tNGS were 88.2 and 94.1%, respectively. The respective sensitivities for HE staining combined with AFB, HE staining combined with PCR, HE staining combined with IHC using anti-MPT64, and Xpert MTB/RIF were 30.1, 49.5, 47.3, and 59.1%. The specificities for these methods were 82.4, 88.2, 94.1, and 94.1%, respectively. Analysis of drug resistance based on tNGS results indicated that 10 of 93 TB patients (10.75%) had potential drug resistance.

Conclusion

Targeted next-generation sequencing achieved higher accuracy than other established diagnostic methods, and can play a crucial role in the rapid and accurate diagnosis of TB, including drug-resistant TB.

Culture-Free Whole Genome Sequencing of Mycobacterium tuberculosis Using Ligand-Mediated Bead Enrichment Method

Background

Direct whole genome sequencing (WGS) of Mycobacterium tuberculosis (Mtb) can be used as a tool to study drug resistance, mixed infections, and within-host diversity. However, WGS is challenging to obtain from clinical samples due to low number of bacilli against a high background.

Methods

We prospectively collected 34 samples (sputum, n = 17; bronchoalveolar lavage, n = 13; and pus, n = 4) from patients with active tuberculosis (TB). Prior to DNA extraction, we used a ligand-mediated magnetic bead method to enrich Mtb from clinical samples and performed WGS on Illumina platform.

Results

Mtb was definitively identified based on WGS from 88.2% (30/34) of the samples, of which 35.3% (12/34) were smear negative. The overall median genome coverage was 15.2% (interquartile range [IQR], 7.7%-28.2%). There was a positive correlation between load of bacilli on smears and genome coverage (P < .001). We detected 58 genes listed in the World Health Organization mutation catalogue in each positive sample (median coverage, 85% [IQR, 61%-94%]), enabling the identification of mutations missed by routine diagnostics. Mutations causing resistance to rifampicin, isoniazid, streptomycin, and ethambutol were detected in 5 of 34 (14.7%) samples, including the rpoB S441A mutation that confers resistance to rifampicin, which is not covered by Xpert MTB/RIF.

Conclusions

We demonstrate the feasibility of magnetic bead-based enrichment for culture-free WGS of Mtb from clinical specimens, including smear-negative samples. This approach can also be integrated with low-cost sequencing workflows such as targeted sequencing for rapid detection of Mtb and drug resistance.

Diagnosing adult and pediatric extrapulmonary tuberculosis by MPT64 antigen detection with immunohistochemistry and immunocytochemistry using reproduced polyclonal antibodies

Diagnosing extrapulmonary tuberculosis (EPTB) is challenging. Immunohistochemistry or immunocytochemistry has been used to diagnose tuberculosis (TB) by detection of MPT64 antigen from various extrapulmonary specimens and has shown good diagnostic performance in our previous studies. The test can distinguish between disease caused by Mycobacterium tuberculosis (Mtb) complex and nontuberculous mycobacteria and can be applied on formalin-fixed paraffin-embedded tissue. As the antibodies previously used were in limited supply, a new batch of polyclonal antibodies was developed for scale-up and evaluated for the first time in this study. Our aim was to assess the diagnostic accuracy of the MPT64 test with reproduced antibodies in the high burden settings of Pakistan and India. Patients were enrolled prospectively. Samples from suspected sites of infection were collected and subjected to histopathologic and/or cytologic evaluation, routine TB diagnostics, GeneXpert MTB/RIF (Xpert), and the MPT64 antigen detection test. Patients were followed until the end of treatment. Based on a composite reference standard (CRS), 556 patients were categorized as TB cases and 175 as non-TB cases. The MPT64 test performed well on biopsies with a sensitivity and specificity of 94% and 75%, respectively, against a CRS. For cytology samples, the sensitivity was low (36%), whereas the specificity was 81%. Overall, the MPT64 test showed higher sensitivity (73%) than Xpert (38%) and Mtb culture (33%). The test performed equally well in adults and children. We found an additive diagnostic value of the MPT64 test in conjunction with histology and molecular tests, increasing the yield for EPTB. In conclusion, immunochemical staining with MPT64 antibodies improves the diagnosis of EPTB in high burden settings and could be a valuable addition to routine diagnostics.

Tuberculosis treatment outcomes and associated factors among tuberculosis patients treated at healthcare facilities of Motta Town, Northwest Ethiopia: a five-year retrospective study

Tuberculosis (TB) remains a significant public health concern, particularly in low-resource settings. The treatment outcome is a crucial indicator of the effectiveness of TB treatment programs. Assessing the current treatment outcome and its associated factors is essential for improving patient care and reducing the spread of TB. Therefore, this study aimed to assess TB treatment outcomes and their associated factors among TB patients who received treatment at public healthcare facilities in Motta Town, Northwest Ethiopia. A facility-based retrospective cross-sectional study design was employed in two TB treatment centers in Motta town from January 2017 to December 2021. The study participants were all patients diagnosed with TB who received treatment. A p-value of 0.05 with a 95% confidence interval (CI) was used to determine statistical significance. A total of 362 TB patients were included in the study. The overall treatment success rate was 88.4% (95% CI 85.1, 91.7). Male gender (AOR = 2.40, 95% CI 1.16, 4.98), normal nutritional status (AOR = 3.11, 95% CI 1.33, 7.25), HIV negative status (AOR = 3.35, 95% CI 1.31, 8.60), and non-presumptive drug resistance to TB (AOR = 3.72, 95% CI 1.74, 7.98) were significantly associated with successful TB treatment outcomes (p < 0.05). In the current study, nine out of ten study participants had successful TB treatment outcome rates. Male gender, normal nutritional status, non-presumed drug resistance to TB, and HIV-negative status were significantly associated with successful TB treatment outcomes. By taking risk factors associated with poor treatment outcomes like those found in this study into account, patient management and treatment can be optimized. Sufficient TB control measures for populations are imperative and could significantly reduce the nation's total TB burden.

Diagnostic value of nucleic acid amplification tests for tuberculous pleural effusion

Diagnosing tuberculous pleural effusion (TPE) is challenging for pulmonologists and laboratory scientists. The gold standards for TPE diagnosis are pleural fluid Ziehl-Neelsen staining, Mycobacterium tuberculosis (Mtb) culture and pleural biopsy. These tools have limitations, including low sensitivity, long turnaround time and invasiveness. The nucleic acid amplification test (NAAT) is a rapid and minimally invasive tool for diagnosing TPE. This review summarizes the diagnostic accuracy of available NAATs for TPE, with a focus on the evidence from systematic reviews and meta-analyses. The NAATs summarized in this review include in-house NAATs, GeneXpert-MTB/RIF, GeneXpert-MTB/RIF Ultra, simultaneous amplification and testing-tuberculosis, FluoroType MTB and loop-mediated isothermal amplification.

GYRB - POLYMERASE CHAIN REACTION AND HISTOPATHOLOGIC CHARACTERISTIC FIGURE POTENTIAL FOR DETERMINING DIAGNOSIS OF TUBERCULOUS LYMPHADENITIS

Background

TB lymphadenitis is still a problem that needs serious treatment. In Indonesia, it was reported that 53% of TB cases were extrapulmonary tuberculosis, with the most cases being Lymphadenitis TB, 11.6%. In children, 43% of extrapulmonary tuberculosis cases are TB lymphadenitis. Diagnosis is quite difficult; a method of determining the diagnosis and appropriate comprehensive treatment is required in managing TB Lymphadenitis.

Materials and Methods

In this study, 15 fine needle aspiration biopsy aspirate samples were subjected to molecular examination using the gyrB-polymerase chain reaction method and histopathological observations using the smear method with hematoxylin-eosin staining. Observation of preparations using a microscope with a magnification of 200x.

Results

The histopathological characteristics of the fine needle aspiration biopsy aspirate showed positive results in 4 out of 15 samples, with epithelioid cells arranged in a characteristic granuloma structure, necrotic debris was visible, and cells joined together to form multinucleated giant cells as an inflammatory response to Mycobacterium tuberculosis complex infection. In this study, 6 out of 15 (40%) were detected to be positive in the diagnosis based on molecular detection using a specific target gene gyrB - polymerase chain reaction .

Conclusion

Characteristic features on histopathological examination associated with gyrB - positive polymerase chain reaction on lymphadenitis fine needle aspiration biopsy aspirate samples can be used as a determinant diagnosis of tuberculous lymphadenitis.

Drug Resistance in Osteoarticular Tuberculosis: A Study From an Endemic Zone

BACKGROUND

The present study was undertaken to determine the incidence of drug resistance against anti-tubercular drugs among patients from an endemic zone.  Methodology: Forty consecutive clinico-radiologically diagnosed patients of osteoarticular tuberculosis (29: spine, 11: extraspinal) were enrolled. Pus from needle aspiration was taken in 31 cases, tissue following spinal decompression in seven, synovial in one, and sinus edge biopsy in one. The pus/tissue was subjected to acid-fast bacilli (AFB) staining and liquid culture, sensitivity to 13 anti-tubercular drugs (Isoniazid (INH), rifampicin (RIF), kanamycin (KAN), amikacin (AMK,) capreomycin (CAP), ethionamide (ETH), levofloxacin (LEV), moxifloxacin (MOX), linezolid (LNZ), para-amino-salicylic acid (PAS), bedaquiline (BDQ), delamanid (DLM), and clofazimine (CFO)) were checked, and histopathological/cytopathological examination and molecular tests were performed.   Results: The mean age of patients was 29.07(9-65) years; 21 were female and 19 were male. The diagnostic accuracy for tuberculosis was 20% by AFB smear, 65% by liquid culture, 82.5% by histopathology, and 90% by cartridge-based nucleic acid amplification testing (CBNAAT). All culture-positive isolates were identified as Mycobacterium tuberculosis with no non-tubercular Mycobacterium. The drug resistance detected on CBNAAT was 11.1%, line probe assay (LPA) first line was 15.4%, LPA second line was 4%, and liquid drug susceptibility testing (DST) 11.5%. We detected 15.4% INH resistance, 11.1% RIF, 7.6% LEV, 3.8% MOX and PAS. No resistance was detected against second-line injectable drugs (SLID), ETH, LNZ, BDQ, DLM, and CFO.    Conclusions: No single laboratory modality can ascertain the diagnosis in all cases; hence, samples should be sent for all tests in tandem. In the presence of insufficient samples, tissue may be subjected to CBNAAT and histopathology to arrive at tissue diagnosis. In this subset, overall drug resistance incidence was 12.5% (5/40) with one patient each of isolated INH and RIF resistance, one of multidrug-resistance (MDR), and two of pre-extensively drug-resistant (pre-XDR). Primary drug resistance came out to be 11.1% (4/36) with one patient each of isolated INH and RIF resistance, one of MDR, and one Pre-XDR.

Diagnosis of extrapulmonary tuberculosis by GeneXpert MTB/RIF Ultra assay

INTRODUCTION

Diagnosis of extrapulmonary tuberculosis (EPTB) is an arduous task owing to different anatomical locations, unusual clinical presentations, and sparse bacillary load in clinical specimens. Although GeneXpert® MTB/RIF is a windfall in TB diagnostics including EPTB, it yields low sensitivities but high specificities in many EPTB specimens. To further improve the sensitivity of GeneXpert®, GeneXpert® Ultra, a fully nested real-time PCR targeting IS6110, IS1081 and rpoB (Rv0664) has been endorsed by the WHO (2017), wherein melt curve analysis is utilized to detect rifampicin-resistance (RIF-R).

AREA COVERED

We described the assay chemistry/work design of Xpert Ultra and evaluated its performance in several EPTB types, that is, TB lymphadenitis, TB pleuritis, TB meningitis, and so on, against the microbiological reference standard or composite reference standard. Notably, Xpert Ultra exhibited better sensitivities than Xpert, but mostly at the compensation of specificity values. Moreover, Xpert Ultra exhibited low false-negative and false-positive RIF-R results, compared with Xpert. We also detailed other molecular tests, that is, Truenat MTBTM/TruPlus, commercial real-time PCR, line probe assay, and so on, for EPTB diagnosis.

EXPERT OPINION

A combination of clinical features, imaging, histopathological findings, and Xpert Ultra are adequate for definite EPTB diagnosis so as to initiate an early anti-tubercular therapy.

A case report of a 16-year-old male with extrapulmonary tuberculosis presenting as multiloculated mediastinal, pleural, and paravertebral fluid collections with chest pain, Eldoret, Kenya

Key Clinical Message

Extrapulmonary TB presenting as multiloculated pleural fluid collections is rare in persons less than 18 years of age, but it can occur. High index of suspicion is important in establishing early diagnosis and treatment to reduce morbidity and mortality.

Abstract

We present a case report of an immunocompetent African young man who presented with persistent chest pain and fever, and was diagnosed with extrapulmonary tuberculosis (EPTB) following chest CT scan, pleural biopsy histopathology examination, and Ziehl-Neelsen (ZN) staining, and pleural fluid Gene Xpert studies.

Diagnostic Performance of Different Laboratory Methods for the Detection of Extrapulmonary Tuberculosis

Accurate and appropriate extrapulmonary tuberculosis (EPTB) diagnosis remains challenging due to its paucibacillary nature, requirement of invasive collection procedures, and lack of sensitive tests. This study investigated the diagnostic performance of different methods for the diagnosis of EPTB. A total of 1340 EPTB specimens were collected from presumptive EPTB patients from four different hospitals between November 2015 and March 2017. The collected specimens were tested with AFB microscopy, culture, Xpert MTB/RIF assay (Xpert), and MTBDRplus assay. Among the 1340 EPTB specimens, 49 (3.66%), 141 (10.52%), 166 (12.39%), and 154 (11.49%) were positive in AFB microscopy, culture, Xpert MTB/RIF, and MTBDRplus assay, respectively. A total of 194 (14.9%) cases were found positive in at least one of these methods. Using culture as a reference standard, the sensitivity and specificity of AFB microscopy, Xpert MTB/RIF, and MTBDRplus assay were: 27.0%/99.1%, 83.7%/96.0%, and 79.4%/96.5%, respectively. Compared to the composite reference standard, the sensitivity of culture, AFB microscopy, Xpert MTB/RIF, and MTBDRplus assay was 72.7%, 25.3%, 85.6%, and 79.4%, respectively, with a specificity of 100% for all the methods. The Xpert MTB/RIF assay showed the highest sensitivity compared to other methods. Considering the short turnaround time and promising findings, Xpert MTB/RIF assay should be integrated into national TB guidelines as a routine diagnostic test.

Extrapulmonary Tuberculosis: An Otorhinolaryngologist's Perspective

Objective

The study aimed to determine the clinical manifestations and epidemiology of extrapulmonary tuberculosis (EPTB) of the head and neck in the otorhinolaryngeal regions. There is an increase in the incidence of EPTB in recent years because of increase in immunocompromised states and development of resistant bacteria. The clinical symptoms and signs of EPTB of the otorhinolaryngeal regions overlap with that of malignancies and other diseases in otorhinolaryngology thereby requiring correct early diagnosis so as to avoid unnecessary surgeries and procedures with initiation of appropriate anti tuberculous treatment under RNTCP.

Study design

Our prospective study was done on 45 patients who attended the ENT OPD at a tertiary care centre in Southern India over a period of 18 months with diagnosed EPTB of the otorhinolaryngeal regions.

Results

The study included 29 (64.4%) patients who presented with cervical lymphadenopathy, 11 (24.4%) patients with tuberculous laryngitis, 3 (6.6%) patients with tuberculous otitis media and 1 each with nasal and oral cavity tuberculosis. In our study 6 (13.3%) patients had co-existing pulmonary tuberculosis, 8 (18%) had diabetes, 5 (11%) had past history of tuberculosis and 7 (16%) had contact with patient with tuberculosis.

Conclusion

A high index of suspicion of EPTB must be kept among patients where (i) the clinical symptoms are out of proportion to the signs, (ii) common treatment fails or (iii) there is persistence or recurrence of symptoms despite therapy. The challenge is in confirming diagnosis which requires histopathological examination (HPE) of the tissue specimen. The timely diagnosis and initiation of anti tuberculous treatment (ATT) as per RNTCP helps in complete recovery thereby reducing morbidity.

Evaluation of Immunohistochemistry Technique for Diagnosis of Extrapulmonary Tuberculosis in Biopsy Tissue Specimen as Compared to Composite Diagnostic Criteria

Introduction

Diagnosis of extrapulmonary tuberculosis (EPTB) has been challenging owing to its paucibacillary nature and diverse clinical manifestations. Immunohistochemistry (IHC) on biopsy specimens has presented a new perspective toward improving tuberculosis diagnosis. MPT64 is a unique antigen that has shown high sensitivity and specificity compared to other conventional techniques in its ability to diagnose tuberculosis as well as differentiate it from nontubercular mycobacteria. In this study, we aimed to analyze the utility of anti-MPT64 in the diagnosis of EPTB.

Methods

In this cross-sectional study, conducted over a period of 1 year, 52 nonrepetitive samples from 52 participants with a presumptive diagnosis of EPTB were collected and processed. The specimens were subjected to Ziehl-Neelsen staining, GeneXpert, tissue culture by mycobacterium growth indicator tube, H and E staining, and IHC with anti-MPT64. The sensitivity and specificity of anti-MPT64 was computed against a composite diagnostic criterion.

Results

Fifty-two consecutive participants satisfying the study criteria were recruited. The mean age of the study population was 37.35 ± 18.71 years. Lymph node specimen accounted for majority of the specimen processed (n = 20, 38.5%). The sensitivity of anti-MPT64 in the diagnosis of EPTB was 68.29%, specificity was 90.90%, positive predictive value was 96.55%, and negative predictive value was 43.47%, when composite criteria were considered standard for diagnosis.

Conclusion

Immunohistochemical staining by anti-MPT64 is useful in establishing microbiological diagnosis of EPTB on biopsy specimens.

Rheumatoid or tubercular: Flexor tenosynovitis of the wrist with rice bodies

Rice bodies are formed mainly in tenosynovitis and bursitis of rheumatoid or tubercular origin. It rarely presents with compressive ulnar neuropathy. A 35-year-old female presented with painful swelling in the volar aspect of the left wrist and incomplete flexion of the little finger. The laboratory tests revealed ESR 10 mm/1^st hr and C-reactive protein, rheumatoid factor, and anti-cyclic citrullinated peptide tests were negative. Thickened and distended ulnar bursa with rice bodies was seen on magnetic resonance imaging (MRI). Thorough drainage, debridement, and synovectomy were done. Epithelioid cell granulomas with multinucleated giant cells on microscopy and the strongly positive Mantoux test prompted us to start anti-tubercular treatment. The wound healed uneventfully with good recovery of range of motion of the little finger at one-year follow up. Rice bodies can be a diagnostic dilemma in the absence of classical signs of their rheumatoid or tubercular origin.

Evaluation of modified bleach technique for the detection of acid fast bacilli in lymph node aspirate at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

Background

Tuberculous Lymphadenitis (TBLN) is the commonest form of extrapulmonary tuberculosis. Definitive diagnosis of TBLN is difficult due to the low efficacy of the routine diagnostic techniques as compared to culture.

Objective

To determine whether prior bleach concentration can improve the detection of acid-fast bacilli when compared with conventional Ziehl-Neelsen (ZN) staining by using culture as the gold standard.

Methods

Cross-sectional study was conducted from March 01, 2015 to May 30, 2015. The study subjects were clinically suspected TBLN patients. Fine needle aspiration (FNA) was performed. Two different smears were prepared directly from the first needle pass for cytology and ZN staining. The remaining aspirate was used for the modified bleach concentration. The second needle pass aspirate was transferred into a sterile container containing sterile normal saline. The sediment was inoculated on the Lowenstein Jensen (LJ) medium. Measurement parameters for reliability and validity were used to analyze the results.

Result

A total of 93 participants were included in the study. Fifty-six out of the 93 (60.2 %) cases were positive for mycobacterium tuberculosis complex on LJ culture. The detection rates of direct ZN staining and modified bleach method were 20.4 % and 44.1 %, respectively. 73.1 % of the cases showed cytomorphological features consistent with TBLN by cytologic examination. The sensitivities of direct ZN staining and modified bleach method and cytomorphology were 32.0 %, 67.8 %, and 92.8 %, respectively.

Conclusion

Implementation of bleach concentration increases the detection rate of AFB over the direct ZN method. The bleach method can also be easily performed and provide a safe working environment by reducing infections.

Utility of RNTCP (NTEP) guidelines in microbiological confirmation of pediatric tuberculosis

OBJECTIVE

To estimate the proportion of microbiologically confirmed disease among children diagnosed with tuberculosis using RNTCP guidelines.

MATERIALS AND METHODS

Retrospective chart review of a cohort of 151 children (aged between 1 month and 18 years) diagnosed with Tuberculosis between December 2016 and June 2020 at a pediatric department of a tertiary care hospital. We collected information on AFB (Acid Fast Bacillus) smear and Cartridge Based Nucleic Acid Amplification Test (CB NAAT) results.

RESULTS

Out of 151 children with a diagnosis of Tuberculosis, 66 (44%) children were found to have microbiologically confirmed disease. Confirmatory rate was almost equal in children less than <5 and >5 years (48% vs 52%). Confirmatory rate did not differ between pulmonary and extra pulmonary samples (49% and 53%). Cartridge Based Nucleic Acid Amplification Test outperformed AFB by 10%, which was statistically significant (p = .000 by fisher exact test).

CONCLUSION

Although considered paucibacillary in nature, microbiological confirmation can be obtained in almost up to half of children with a diagnosis of TB by using RNTCP guidelines. Neither young age nor type of TB is a deterrent to bacteriologically confirm TB in children.

Flow cytometry, molecular analysis, and other special techniques (in Serous Fluid Cytopathology)

Morphological and architectural pattern evaluations play a major role in the rpretation of hematopoietic neoplasms. However, confirmation of diagnosis, classification, prognosis, and risk stratification are highly dependent on the utilization of multiple ancillary studies. The importance of these ancillary studies increases in evaluating serous fluid samples, as these samples lack architecture and patterns. Likewise, the morphology can be disturbed by sample preparation. The most common ancillary studies utilized are flow cytometry, immunohistochemistry for immunophenotyping, Fluorescent In Situ Hybridization (FISH), cytogenetics for structural and gene rearrangements, and molecular studies for mutational analysis. Among them, flow cytometry analysis is the handiest test to perform with high diagnostic yield on serous fluid specimens. In this article we will discuss the use, caveat, and role of the most common ancillary studies on serous fluid specimen evaluation. This review article will be incorporated finally as one of the chapters in CMAS (CytoJournal Monograph/Atlas Series) #2. It is modified slightly from the chapter by the initial authors (Choladda Vejabhuti, MD and Chung-Che (Jeff) Chang, MD, PhD) in the first edition of Diagnostic Cytopathology of Serous Fluids.

Comparative Evaluation of Clinical, Cytological and Microbiological Profile in Abdominal vs. Cervical Lymph Nodal Tuberculosis with Special Emphasis on Utility of Auramine-O Staining

Context:

Extrapulmonary tuberculosis (EPTB) especially abdominal lymph nodal tuberculosis (LNTB) poses a unique diagnostic challenge. The clinical, cytological, and microbiological profiles, especially with respect to the use and role of Auramine –O (AO) stain, are not as well characterized in abdominal LNTB as cervical LNTB and were evaluated in the present comparative study.

Subjects and Methods:

This study was conducted in the Department of Pathology of a tertiary care hospital in Shillong, Meghalaya in 540 clinical suspected cases of tuberculosis who underwent FNAC. The smears were submitted for Leishman's stain for cytological analysis, along with ZN and Auramine O stain for demonstration of the organism, analyzed, and scored and the results were compared with culture wherever available. The results from abdominal and cervical lymph nodal tuberculosis were compared using Microsoft Excel and SPSS software.

Results:

Out of 540 cases, most were tuberculosis (266) followed by reactive lymphadenitis (162), malignancy, and acute necrotizing lesion. On comparing, abdominal lymph nodes (n = 163) were more likely to reveal cheesy/purulent material macroscopically, necrotizing lymphadenitis along with ZN stain and Auramine positivity (P < 0.05) while cervical lymph nodes (n = 66) revealed a higher proportion of granulomatous lymphadenitis and culture positivity (P < 0.05). The sensitivity, NPV, and diagnostic accuracy of AO stain (85.9%, 48.0%, and 62.3%) were higher as compared to ZN stain (47.4%, 39.3%, and 51.9%) with culture as the gold standard. The combined sensitivity of Ziehl Neelsen stain and Auramine stain was 92.05%.

Conclusion:

Cytological and microbiologic features of abdominal LNTB differ from cervical LNTB. Moreover, AO stain increases the smear positivity, is almost twice as sensitive as ZN stain and should be used as an adjunct in cytological material wherever available.

Performance assessment of SD Bioline TB MPT64 assay for the diagnosis of Mycobacterium tuberculosis complex in Lagos, Nigeria

This study assessed the performance of SD Bioline MPT64 immunochromatographic test for the identification of Mycobacterium tuberculosis complex (MTBC) in Nigeria.A total of 157 mycobacterial isolates, comprising 120 (76.4%) MTBC (M. tuberculosis, 112; M. africanum, 5; M. bovis, 3) and 37 (23.6%) non-tuberculous mycobacteria (NTM) isolates from patients attending six DOTS centers in Lagos between June 2012 and July 2014 were analyzed. All the isolates were grown on Bactec MGIT960 liquid media and identified in parallel by the conventional method and MPT64 immunochromatographic test. Discrepant results were resolved using the line probe assay.The comorbid disease rates for HIV and type 2 diabetes were 20.9% and 8.2%, respectively. Compared to the conventional method, SD Bioline MPT64 identified 117 MTBC isolates correctly, producing a sensitivity of 97.5% (95% CI, 92.9-99.2) at a shorter growing median time of 11 days compared to 26 days by the conventional method. The three undetected MTBC were confirmed by the line probe assay to be M. tuberculosis strains. The test also identified all the NTM correctly producing a specificity of 100% (95% CI, 90.7-100).This study supports the integration of SD Bioline TB MPT64 antigen test into diagnostic workflow for rapid MTBC case identification in Nigeria.

Tuberculosis presenting as arthritis of the ankle: A case report

Tuberculosis presenting as monoarticular involvement in immunocompetent patients is rare. Here, we report a Sri Lankan patient presenting with ankle swelling due to tuberculosis with no other extrapulmonary or pulmonary involvement. Magnetic resonance imaging showed destruction of articular cartilage of the ankle joint with chronic inflammation of the subtalar joint. The diagnosis was confirmed by synovial tissue culture which was positive for Mycobacterium tuberculosis. The patient recovered uneventfully with anti-tuberculosis treatment. Therefore, a high degree of suspicion is necessary to diagnose extrapulmonary tuberculosis when patients are presenting with atypical monoarthritis.

Hospitalizations and Treatment Outcomes in Patients with Urogenital Tuberculosis in Tashkent, Uzbekistan, 2016-2018

Despite the global shift to ambulatory tuberculosis (TB) care, hospitalizations remain common in Uzbekistan. This study examined the duration and determinants of hospitalizations among adult patients (≥18 years) with urogenital TB (UGTB) treated with first-line anti-TB drugs during 2016–2018 in Tashkent, Uzbekistan. This was a cohort study based on the analysis of health records. Of 142 included patients, 77 (54%) were males, the mean (±standard deviation) age was 40 ± 16 years, and 68 (48%) were laboratory-confirmed. A total of 136 (96%) patients were hospitalized during the intensive phase, and 12 (8%) had hospital admissions during the continuation phase of treatment. The median length of stay (LOS) during treatment was 56 days (Interquartile range: 56–58 days). LOS was associated with history of migration (adjusted incidence rate ratio (aIRR): 0.46, 95% confidence interval (CI): 0.32–0.69, p < 0.001); UGTB-related surgery (aIRR: 1.18, 95% CI: 1.01–1.38, p = 0.045); and hepatitis B comorbidity (aIRR: 3.18, 95% CI: 1.98–5.39, p < 0.001). The treatment success was 94% and it was not associated with the LOS. Hospitalization was almost universal among patients with UGTB in Uzbekistan. Future research should focus on finding out what proportion of hospitalizations were not clinically justified and could have been avoided.

Differential diagnosis of disseminated Mycobacterium avium and Mycobacterium tuberculosis infection in HIV patients using duplex PCR

Background: Disseminated Mycobacterium avium complex (MAC) and Mycobacterium tuberculosis infections have almost similar clinical presentations but require different therapeutic management. Materials & methods: A duplex PCR was designed based on the sequence variation between the genes encoding catalase-peroxidase (KatG) of M. avium complex and M. tuberculosis, so as to discriminate MAC, M. tuberculosis and mixed mycobacterial (MAC + M. tuberculosis) infections in HIV patients. Results: An accurate, single-step differential diagnosis of disseminated mycobacterial infections in HIV patients was achieved with specific detection of a single band each for M. avium (120 bp) and M. tuberculosis (90 bp) and two bands for the mixed (120 and 90 bp) infections. Conclusion: katG gene-based duplex PCR can facilitate quick differential diagnosis of disseminated MAC and M. tuberculosis infections in HIV patients.

Tuberculous Lymphadenitis in a Patient Receiving PD-1 Inhibitor for Melanoma: A Case Report and Brief Literature Review

Oncolytic immunotherapy is a novel and promising approach in clinical oncology practice. Currently, immune checkpoint inhibitors (ICIs) are the first-line treatment options for disseminated melanoma. Nivolumab is a well-defined ICI that blocks programmed cell death 1 (PD-1) and mainly increases anti-tumor immunity. The opportunistic infections are not expected with ICI therapies due to their immune reactivation effects. To date, only a few cancer patients have been reported with activated TB during ICI therapy. Here, we presented a young female patient diagnosed with histologically-confirmed tuberculous lymphadenitis while on nivolumab therapy for metastatic melanoma. The current case report represents the first described tuberculous lymphadenitis case related to anti-PD-1 based monoclonal antibody therapy. The mechanism underlying the development of TB with PD-1 inhibitor use has not been illuminated yet. Triggering of excessive inflammatory responses with ICIs therapy is a potential cause. Considering the increased utilization of ICI-based immunotherapies, the TB screening should be considered in all patients before starting PD-1 inhibitor therapy.

Molecular characterization and drug resistance patterns of Mycobacterium tuberculosis complex in extrapulmonary tuberculosis patients in Addis Ababa, Ethiopia

Background

Molecular characterization of Mycobacterium tuberculosis (MTB) is important to understand the pathogenesis, diagnosis, treatment, and prevention of tuberculosis (TB). However, there is limited information on molecular characteristics and drug-resistant patterns of MTB in patients with extra-pulmonary tuberculosis (EPTB) in Ethiopia. Thus, this study aimed to determine the molecular characteristics and drug resistance patterns of MTB in patients with EPTB in Addis Ababa, Ethiopia.

Methods

This study was conducted on frozen stored isolates of EPTB survey conducted in Addis Ababa, Ethiopia. A drug susceptibility test was performed using BACTEC-MGIT 960. Species and strain identification were performed using the Geno-Type MTBC and spoligotyping technique, respectively. Data were entered into the MIRU-VNTRplus database to assess the spoligotype patterns of MTB. Analysis was performed using SPSS version 23, and participants’ characteristics were presented by numbers and proportions.

Results

Of 151 MTB isolates, 29 (19.2%) were resistant to at least one drug. The highest proportion of isolates was resistant to Isoniazid (14.6%) and Pyrazinamide (14.6%). Nine percent of isolates had multidrug-resistant TB (MDR-TB), and 21.4% of them had pre-extensively drug-resistant TB (pre-XDR-TB). Among the 151 MTB isolates characterized by spoligotyping, 142 (94.6%) had known patterns, while 9 (6.0%) isolates were not matched with the MIRU-VNTRplus spoligotype database. Of the isolates which had known patterns, 2% was M.bovis while 98% M. tuberculosis. Forty-one different spoligotype patterns were identified. The most frequently identified SpolDB4 (SIT) wereSIT149 (21.2%), SIT53 (14.6%) and SIT26 (9.6%). The predominant genotypes identified were T (53.6%), Central Asia Strain (19.2%) and Haarlem (9.9%).

Conclusion

The present study showed a high proportion of MDR-TB and pre-XDR-TB among EPTB patients. The strains were mostly grouped into SIT149, SIT53, and SIT26. The T family lineage was the most prevalent genotype. MDR-TB and pre-XDR-TB prevention is required to combat these strains in EPTB. A large scale study is required to describe the molecular characteristics and drug resistance patterns of MTB isolates in EPTB patients.

Mycobacterium abscessus - an uncommon, but important cause of peritoneal dialysis-associated peritonitis - case report and literature review

BACKGROUND

Peritoneal dialysis (PD) is a form of therapy for end-stage kidney disease (ESKD), and peritonitis is a known complication. Mycobacterium (M) species associated peritonitis in PD patients is uncommon. Our experience of managing PD associated peritonitis caused by M abscessus in a middle-aged man with ESKD due to focal segmental glomerulosclerosis is shared in this article with a review of the literature on this condition.

CASE PRESENTATION

A 49-year old man presented to our unit with symptoms of peritonitis and cloudy PD effluent. Initial analysis of PD fluid showed Gram stain was negative, with no organism grown. Empirical PD peritonitis treatment with intra-peritoneal antibiotics did not improve his symptoms and he required intravenous antibiotics, PD catheter removal and a switch to haemodialysis. Cultures of the PD fluid later grew M abscessus, and the antibiotic regimen was changed appropriately, leading to clinical improvement.

CONCLUSION

M abscessus associated peritonitis in PD patients is rare. It needs to be borne in mind when clinical improvement is not seen with standard broad-spectrum antibiotics, especially in situations where the PD fluid is initially deemed to be culture negative. PD fluid samples should be sent for acid-fast bacillus and if detected, should be further analysed with genome-wide sequencing to confirm the species of the Mycobacterium. Prompt removal of the catheter with peritoneal washout is critical for clinical improvement.

Evaluation of genotype MTBDRplus V2 and genotype MTBDRsl V2 for the diagnosis of extrapulmonary tuberculosis in India

Microbiological diagnosis of extra-pulmonary tuberculosis (EPTB) has been one of the most difficult aspects of tuberculosis (TB) management. Availability of better imaging and diagnostic modalities has led to an increase in the number of diagnosed cases. The current upsurge in multidrug-resistant tuberculosis warrants routine testing of EPTB samples for resistance at baseline with shorter turn-around time. A total of 369 EPTB specimens were subjected to Ziehl-Neelsen (ZN) stain, liquid culture (LC) with phenotypic drug susceptibility testing, MTBDRplus V.2 and MTBDRsl V.2. The molecular categorisation of resistant specimens was further reconfirmed with sequencing. The sensitivity and specificity of MTBDRplus V.2 to detect Mycobacterium tuberculosis (MTB) when compared to ZN stain was 97.9% and 89.2%, respectively while it was 73.4% and 83.8%, respectively when compared to LC. Similarly, for MTBDRsl V.2, the sensitivity and specificity for detection of MTB when compared with ZN was 95.6% and 91.9%, respectively and 75% and 89.2%, respectively when compared to LC. In smear-positive specimens, 94% (141/150) and 86% (129/150) valid results were observed in MTBDRplus V.2 and MTBDRsl V.2, respectively. The utilisation of both MTBDRplus V.2 and MTBDRsl V.2 for the diagnosis of smear-positive EPTB specimens would be useful in programmatic management of TB in high-burden settings.

Diagnosis of Osteoarticular Tuberculosis: Perceptions, Protocols, Practices, and Priorities in the Endemic and Non-Endemic Areas of the World-A WAIOT View

There has been a major resurgence of tuberculosis (TB) and drug-resistant tuberculosis in the last few decades. Although it has been brought under control in most Western countries, it is still a major cause of death in endemic regions like India. Osteoarticular tuberculosis (OA TB) forms a small proportion of the total cases of tuberculosis. Perceptions and practices of orthopedic surgeons are entirely different in endemic and non-endemic regions around the world, due to the vast difference in exposure. Literature from endemic areas puts stress on clinico-radiological diagnosis and empirical anti-tubercular treatment (ATT). Such practices, although non-invasive, simple to implement, and economical, carry a significant risk of missing TB mimics and developing drug resistance. However, OA TB is still perceived as a “diagnostic enigma” in non-endemic regions, leading to a delay in diagnosis. Hence, a high index of suspicion, especially in a high-risk population, is needed to improve the diagnosis. Evolving drug resistance continues to thwart efforts to control the disease globally. This review article discusses the perceptions and practices in different parts of the world, with India as an example of the endemic world, and lays down priorities for overcoming the challenges of diagnosing osteoarticular TB.

Performance of conventional histopathology and GeneXpert MTB/RIF in the diagnosis of spinal tuberculosis from bone specimens: A prospective clinical study

OBJECTIVE

Xpert MTB/RIF is recommended to detect pulmonary tuberculosis; however, there is insufficient data on its utility for bone samples. This study aimed to assess the accuracy of Xpert MTB/RIF compared with conventional histopathology in diagnosing spinal tuberculosis (STB) based on bone specimens in high burden settings.

MATERIALS AND METHODS

Totally, 128 suspected STB participants were enrolled into this study. The bone specimens were obtained through puncture or operation for histological and Xpert MTB/RIF analyses, so as to compare their accuracy in diagnosing STB by the composite reference standard (CRS).

RESULTS

Finally, 106 subjects with suspected STB were recruited into the analysis, including 27 confirmed and 33 clinically diagnosed STB patients. Relative to histopathology, Xpert MTB/RIF achieved a 86.7% sensitivity, and 12 out of 30 STB patients were positive, while the negative results in them were obtained upon histopathology. Based on CRS, Xpert MTB/RIF yielded a 63.3% sensitivity, which significantly elevated relative to that obtained upon histopathological test (50.0%, p < 0.001). In addition, the pooled sensitivity obtained using the above 2 approaches was as high as 95.0%, which was higher than that of any of the 2 approaches alone. The pooled specificity was 97.8%. Moreover, the area under the curve (AUC) value was 0.75 for Xpert MTB/RIF and 0.81 for histopathology, with no statistical significance. The two methods showed moderate concordance in the diagnosis of STB.

CONCLUSIONS

The Xpert MTB/RIF test achieves superior specificity and fair sensitivity, which can not be recommended to replace the conventional examinations for the diagnosis of STB. The combined application of these 2 approaches can improve the pooled diagnostic sensitivity and accuracy for STB.

ENT manifestations of tuberculosis: an important aspect of ENT practice

Tuberculosis involving organs other than the lungs is termed as 'extra pulmonary tuberculosis'. Tuberculosis (TB) remains a worldwide public health problem despite the fact that the causative organism was discovered more than 100 years ago. The present study was conducted to assess different manifestations of tuberculosis affecting the ear, nose and throat (ENT) in patients attending the outpatient department in a total of 520 cases of tuberculosis. One hundred and eight cases were of extra pulmonary tuberculosis. Sixty nine cases had the manifestations of TB in the ENT region. These included patients with tuberculous cervical lymphadenopathy (91.35), laryngeal TB (4.3%), tuberculous otitis media (1.4%), nasal TB (1.4%) and oral tuberculosis (1.4%). Extra pulmonary tuberculosis constitutes about 15-20% of all tuberculosis cases as per WHO survey and it is 20.6% in the present study.

Sensitivity and Specificity of Gene Xpert in the Diagnosis of Spinal Tuberculosis: A Prospective Controlled Clinical Study

STUDY DESIGN

Prospective matched cohort study.

OBJECTIVE

To evaluate the sensitivity and specificity of Gene Xpert in the diagnosis of spinal tuberculosis.

METHODS

From January 2016 to August 2018, Gene Xpert results were prospectively studied in 68 patients of clinicoradiologically suspected spinal tuberculosis (STB) and a control group (CG) of 92 patients, all of whom underwent computed tomography-guided/C-arm-guided/open surgical biopsy. Sensitivity, specificity, positive predictive value, and negative predictive value are obtained using standard equations.

RESULTS

Out of 68 cases of STB, Gene Xpert was positive in 62 (true positive: 62/68) and negative in 6 (false negative: 6/68). Gene Xpert was negative for all 92 cases of CG (true negative: 92/92, false positive 0/92). Thus, in our series, sensitivity of Gene Xpert is 91.18%, specificity is 100%, positive predictive value is 100%, and negative predictive value is 93.88%. Out of all cases of STB, 62/68 (91.18%) were Gene Xpert positive, but only 35/64 (54.69%) was acid-fast bacilli (AFB) culture positive and 53/60(88.33%) was histopathologically conclusive of TB. Also, Gene Xpert was positive in 7/7 (100%) cases of STB in which histopathology were inconclusive and 25/29 (86.21%) cases of STB in which AFB culture was negative.

CONCLUSION

In STB, Gene Xpert clearly outperforms AFB culture and histopathology due to its high sensitivity and specificity apart from being rapid in diagnosis. Hence it is justified to diagnose spinal tuberculosis by Gene Xpert though histopathology is confirmative and AFB culture remains the gold standard.

Utility of smear microscopy and GeneXpert for the detection of Mycobacterium tuberculosis in clinical samples

Introduction

Rapid identification of Mycobacterium tuberculosis (MTB), its resistance to rifampicin and differentiation of MTB from nontuberculous mycobacteria (NTM) is necessary in the management of mycobacterial diseases. Culture, the "gold standard" for the detection of MTB, is time consuming. In spite of its rapidity and low cost, smear microscopy has poor sensitivity for the detection of acid-fast bacilli (AFB). A real-time PCR based rapid diagnostic method like GeneXpert MTB/RIF assay can simultaneously detect M. tuberculosis and rifampicin (RIF) resistance. Hence, we aim to compare the performance of GeneXpert MTB/RIF assay with smear microscopy and culture.

Methods

In this descriptive cross-sectional study, we compared the performance of GeneXpert in pulmonary (N=127) and extrapulmonary (N=48) clinical specimens with other diagnostic methods like culture, Auramine O (AO), and Ziehl Neelsen (ZN) staining. Rifampicin resistance was detected only by GeneXpert. Demographic data and clinical history of the subjects were collected from the patient's hospital records.

Results

AO and ZN staining when compared with mycobacterial growth indicator (MGIT) culture showed the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 68.6, 95.7, 80, 92.4, 90.3% and 65.7, 95.7, 79.3, 91.8, 89.7%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of GeneXpert was 88.6, 93.6, 77.5, 97.0 and 92.6%, respectively.

Conclusions

GeneXpert is the best available rapid diagnostic method as it can detect MTB and rifampicin resistance gene simultaneously. Accuracy and negative predictive value of GeneXpert was found to be better than AFB staining. Thus, a negative GeneXpert test can rule out TB. Further, a negative GeneXpert and a positive smear microscopy results indicate the presence of NTM. However, GeneXpert is expensive and needs sophisticated instrument when compared to smear microscopy.

Diagnosis and clinical outcomes of extrapulmonary tuberculosis in antiretroviral therapy programmes in low- and middle-income countries: a multicohort study

INTRODUCTION

Extrapulmonary tuberculosis (EPTB) is difficult to confirm bacteriologically and requires specific diagnostic capacities. Diagnosis can be especially challenging in under-resourced settings. We studied diagnostic modalities and clinical outcomes of EPTB compared to pulmonary tuberculosis (PTB) among HIV-positive adults in antiretroviral therapy (ART) programmes in low- and middle-income countries (LMIC).

METHODS

We collected data from HIV-positive TB patients (≥16 years) in 22 ART programmes participating in the International Epidemiology Databases to Evaluate AIDS (IeDEA) consortium in sub-Saharan Africa, Asia-Pacific, and Caribbean, Central and South America regions between 2012 and 2014. We categorized TB as PTB or EPTB (EPTB included mixed PTB/EPTB). We used multivariable logistic regression to assess associations with clinical outcomes.

RESULTS AND DISCUSSION

We analysed 2695 HIV-positive TB patients. Median age was 36 years (interquartile range (IQR) 30 to 43), 1102 were female (41%), and the median CD4 count at TB treatment start was 114 cells/μL (IQR 40 to 248). Overall, 1930 had PTB (72%), and 765 EPTB (28%). Among EPTB patients, the most frequently involved sites were the lymph nodes (24%), pleura (15%), abdomen (11%) and meninges (6%). The majority of PTB (1123 of 1930, 58%) and EPTB (582 of 765, 76%) patients were diagnosed based on clinical criteria. Bacteriological confirmation (using positive smear microscopy, culture, Xpert MTB/RIF, or other nucleic acid amplification tests result) was obtained in 897 of 1557 PTB (52%) and 183 of 438 EPTB (42%) patients. EPTB was not associated with higher mortality compared to PTB (adjusted odd ratio (aOR) 1.0, 95% CI 0.8 to 1.3), but TB meningitis was (aOR 1.9, 95% CI 1.0 to 3.1). Bacteriological confirmation was associated with reduced mortality among PTB patients (aOR 0.7, 95% CI 0.6 to 0.8) and EPTB patients (aOR 0.3 95% CI 0.1 to 0.8) compared to TB patients with a negative test result.

CONCLUSIONS

Diagnosis of EPTB and PTB at ART programmes in LMIC was mainly based on clinical criteria. Greater availability and usage of TB diagnostic tests would improve the diagnosis and clinical outcomes of both EPTB and PTB.

The use of real-time polymerase chain reaction and an adenosine deaminase assay for diagnosing pleural tuberculosis

Background

The diagnosis of pleural tuberculosis remains a challenge, because the most widely used conventional diagnostic tools are unable to rapidly detect Mycobacterium tuberculosis in pleural fluid with sufficient sensitivity.

Objectives

The aim of this study was to evaluate the usefulness of an adenosine deaminase assay and real-time polymerase chain reaction (qPCR) in diagnosing pleural tuberculosis.

Methods

One hundred and five consecutive pleural fluid specimens collected between August 2008 and March 2009 were assessed. Among the 105 specimens, 50 (48%) were unconfirmed tuberculosis cases, 21 (20%) were confirmed tuberculosis cases and 34 (32%) were non-tuberculosis cases (controls). Real-time PCR was performed using the Light Cycler Mycobacterium detection kit according to the manufacturer‘s instructions (Roche Diagnostics). An adenosine deaminase assay was carried out using a commercial colorimetric assay kit as a user-defined method on a Beckman DxC 600 Synchron analyser.

Results

The sensitivity of the qPCR was 67% and specificity was 100%. The sensitivity of the adenosine deaminase assay was 80% and specificity was 94%.

Conclusion

The findings show that the adenosine deaminase assay had higher sensitivity than qPCR. Real-time PCR had 100% specificity, thus a combination of the two methods may be useful for the diagnosis of pleural tuberculosis.

Xpert MTB/RIF assay for the diagnosis of rifampicin resistance in different regions: a meta-analysis

Background

To estimate the diagnostic accuracy of Xpert MTB/RIF for rifampicin resistance in different regions, a meta-analysis was carried out.

Methods

Several databases were searched for relevant studies up to March 3, 2019. A bivariate random-effects model was used to estimate the diagnostic accuracy.

Results

We identified 97 studies involving 26,037 samples for the diagnosis of rifampicin resistance. The pooled sensitivity, specificity and AUC of Xpert MTB/RIF for rifampicin resistance detection were 0.93 (95% CI 0.90–0.95), 0.98 (95% CI 0.96–0.98) and 0.99 (95% CI 0.97–0.99), respectively. For different regions, the pooled sensitivity were 0.94(95% CI 0.89–0.97) and 0.92 (95% CI 0.88–0.94), the pooled specificity were 0.98 (95% CI 0.94–1.00) and 0.98 (95% CI 0.96–0.99), and the AUC were 0.99 (95% CI 0.98–1.00) and 0.99 (95% CI 0.97–0.99) in high and middle/low income countries, respectively. The pooled sensitivity were 0.91 (95% CI 0.87–0.94) and 0.91 (95% CI 0.86–0.94), the pooled specificity were 0.98 (95% CI 0.96–0.99) and 0.98 (95% CI 0.96–0.99), and the AUC were 0.98 (95% CI 0.97–0.99) and 0.99 (95% CI 0.97–0.99) in high TB burden and middle/low prevalence countries, respectively.

Conclusions

The diagnostic accuracy of Xpert MTB/RIF for rifampicin resistance detection was excellent.

Visualization of microbes by 16S in situ hybridization in term and preterm placentas without intraamniotic infection

BACKGROUND

Numerous reports have documented bacteria in the placental membranes and basal plate decidua in the absence of immunopathology using histologic techniques. Similarly, independent metagenomic characterizations have identified an altered taxonomic makeup in association with spontaneous preterm birth. Here we sought to corroborate these findings by localizing presumptive intact bacteria using molecular histology within the placental microanatomy.

OBJECTIVE

Here we examined for microbes in term and preterm gestations using a signal-amplified 16S universal in situ hybridization probe set for bacterial rRNA, alongside traditional histologic methods of Warthin-Starry and Gram stains, as well as clinical culture methodologies. We further sought to differentiate accompanying 16S gene sequencing taxonomic profiles from germ-free (gnotobiotic) mouse and extraction and amplicon contamination controls.

STUDY DESIGN

Placentas were collected from a total of 53 subjects, composed of term labored (n = 4) and unlabored cesarean deliveries (n = 22) and preterm vaginal (n = 18) and cesarean deliveries (n = 8); a placenta from a single subject with clinical and histologic evident choriomanionitis was employed as a positive control (n = 1). The preterm cohort included spontaneous preterm birth with (n = 6) and without (n = 10) preterm premature rupture of membranes, as well as medically indicated preterm births (n = 10). Placental microbes were visualized using an in situ hybridization probe set designed against highly conserved regions of the bacterial 16S ribosome, which produces an amplified stable signal using branched DNA probes. Extracted bacterial nucleic acids from these same samples were subjected to 16S rRNA metagenomic sequencing (Illumina, V4) for course taxonomic analysis, alongside environmental and kit contaminant controls. A subset of unlabored, cesarean-delivered term pregnancies were also assessed with clinical culture for readily cultivatable pathogenic microbes.

RESULTS

Molecular in situ hybridization of bacterial rRNA enabled visualization and localization of low-abundance microbes after systematic high-power scanning. Despite the absence of clinical or histologic chorioamnionitis in 52 of 53 subjects, instances of 16S rRNA signal were confidently observed in 13 of 16 spontaneous preterm birth placentas, which was not significantly different from term unlabored cesarean specimens (18 of 22; P > .05). 16S rRNA signal was largely localized to the villous parenchyma and/or syncytiotrophoblast, and less commonly the chorion and the maternal intervillous space. In all term and unlabored cesarean deliveries, visualization of evident placental microbes by in situ hybridization occurred in the absence of clinical or histologic detection using conventional clinical cultivation, hematoxylin-eosin, and Gram staining. In 1 subject, appreciable villous bacteria localized to an infarction, where 16S microbial detection was confirmed by Warthin-Starry stain. In all instances, parallel sample principle coordinate analysis using Bray-Cutis distances of 16S rRNA gene sequencing data demonstrated consistent taxonomic distinction from all negative or potential contamination controls (P = .024, PERMANOVA). Classification from contaminant filtered data identified a distinct taxonomic makeup among term and preterm cohorts when compared with contaminant controls (false discovery rate <0.05).

CONCLUSION

Presumptively intact placental microbes are visualized as low-abundance, low-biomass and sparse populations within the placenta regardless of gestational age and mode of delivery. Their taxonomic makeup is distinct from contamination controls. These findings further support several previously published findings, including our own, which have used metagenomics to characterize low-abundance and low-biomass microbial communities in the placenta.

Diagnostic value of polymerase chain reaction/acid-fast bacilli in conjunction with computed tomography-guided pleural biopsy in tuberculous pleurisy: A diagnostic accuracy study

Patients with tuberculous pleurisy often remain undiagnosed even after blind thoracentesis and closed pleural biopsy (PB). In this study, we assessed the value of computed tomography (CT)-guided core needle biopsy of pleural lesion and evaluated the diagnostic accuracy of polymerase chain reaction (PCR)/staining for acid-fast bacilli (AFB) in suspicious tuberculous pleurisy undiagnosed in blind thoracentesis.Patients with exudative pleural effusion (PE) without specific etiology after blind thoracentesis and closed PB were enrolled in this study. PB specimens were obtained through CT-guided core needle biopsy of pleural lesion, then underwent PCR, AFB, histopathological examination, and some routine tests. Diagnostic values were evaluated through sensitivity, specificity, negative predictive value, positive predictive value, and accuracy.A total of 261 participants (TB group: 241, non-TB group: 20) were recruited. In this cohort, the sensitivity, specificity, and accuracy were 56.0%, 95.0%, and 59.0%, respectively for PCR, whereas 57.3%, 95.0%, and 60.2%, respectively for AFB. Their parallel test achieved an improved sensitivity (76.8%) and accuracy (77.8%), with a slight decrease in specificity (90.0%). In histopathological examination, granuloma was the most common finding in TB group (88.4%, 213/241), but also observed in non-TB group (10.0%, 2/20). In addition, pleural lymphocyte percentage in TB group was significantly higher than that of non-TB group (92% vs 61%, respectively; P = .003). However, no significant differences were found for other biomarkers.CT-guided core needle PB is essential for patients with exudative PE but undiagnosed after blind thoracentesis. Combining with PCR and AFB, it strongly improves the diagnosis of tuberculous pleurisy.

Development and evaluation of rapid and specific sdaA LAMP-LFD assay with Xpert MTB/RIF assay for diagnosis of tuberculosis

There is need for rapid and cost-effective diagnostic test for tuberculosis. The present study was carried out to design a Loop-mediated isothermal amplification (LAMP) assay combined with lateral flow dipstick (LFD) as a point-of-care method for diagnosis of TB. LAMP assay targeting sdaA gene combined with LFD for sequence specific detection was standardized in user friendly and rapid format. It does not require sophisticated instruments and shows visual results instantly. The LAMP-LFD assay was validated using culture confirmed specimens. The assay was evaluated in a cross-sectional study using respiratory specimens collected from patients in Delhi, India and it showed high concordance with GeneXpert MTB/RIF assay. Lateral flow dipstick method has provided an excellent detection format with LAMP method. The LAMP-LFD assay showed high diagnostic accuracy in comparison to other methods and can be used as a point-of-care test in cost-effective manner.

Clinical usefulness of routine AFB culture and MTB PCR of EBUS-TBNA needle rinse fluid

BACKGROUND AND OBJECTIVE

We evaluated the usefulness of acid-fast bacilli (AFB) culture and Mycobacterium tuberculosis (MTB) polymerase chain reaction (PCR) of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) needle rinse fluid for diagnosing tuberculous lymphadenitis.

METHODS

EBUS-TBNA needle rinse fluid was routinely used for AFB culture and MTB PCR. The patients were categorized according to the pre-procedural diagnosis (Group A, suspected/histology-confirmed lung cancer; Group B, extrapulmonary malignancy; and Group C, other benign diseases).

RESULTS

Of the 4672 subjects, 104 (2.2%) were diagnosed with tuberculous lymphadenitis; 1.0%, 4.6% and 12.7% of Group A, B and C, respectively. Tuberculous lymphadenitis was diagnosed in 0.2%, 1.0% and 4.5% Group A, B and C patients, respectively, by histopathology. On addition of AFB culture to histopathology, tuberculous lymphadenitis was diagnosed in 1.0%, 4.4% and 10.3% of Group A, B and C patients, respectively (P < 0.001, P = 0.001 and P = 0.005, respectively). On addition of MTB PCR to histopathology, tuberculous lymphadenitis was diagnosed in 0.4%, 1.9% and 8.8%, respectively (Group C; P = 0.029).

CONCLUSION

Routine AFB culture of needle rinse fluid was useful to increase the diagnostic yield of tuberculous lymphadenitis for all subjects who underwent EBUS-TBNA regardless of pre-procedural diagnosis in an intermediate tuberculosis (TB)-burden country. However, MTB PCR was only useful in subjects with pre-procedural diagnosis of benign pulmonary diseases.

Ultrasound-Guided versus Thoracoscopic Pleural Biopsy for Diagnosing Tuberculous Pleurisy Following Inconclusive Thoracentesis: A Randomized, Controlled Trial

BACKGROUND Traditional diagnostic methods for tuberculosis (TB) cannot be reliably applied to tuberculous pleurisy. Therefore, this prospective, randomized, controlled trial was performed to compare the diagnostic sensitivity and safety of ultrasound-guided cutting-needle pleural biopsy versus thoracoscopic pleural biopsy in patients suspected of tuberculous pleurisy following inconclusive thoracentesis. MATERIAL AND METHODS A total of 196 adult patients with acid-fast bacillus (AFB)-negative exudative pleural effusions clinically suspected of tuberculous pleurisy were recruited. Enrollees were randomized into 2 cohorts: ultrasound-guided cutting-needle pleural biopsy (n=96) or thoracoscopic pleural biopsy (n=96). The overall diagnostic yields, diagnostic sensitivities for tuberculous pleurisy, and post-procedural complications for both cohorts were statistically compared. RESULTS Ultrasound-guided pleural biopsy displayed an overall diagnostic yield of 83%, while thorascopic pleural biopsy displayed a similar overall diagnostic yield of 86% (χ²=1.88, df=1, p=0.17). There were 127 patients conclusively diagnosed with tuberculous pleurisy, resulting in a tuberculous pleurisy prevalence of 65% in this patient population (66% in the ultrasound cohort vs. 63% in the thoracoscopy cohort; p>0.05). Ultrasound-guided pleural biopsy displayed a sensitivity of 82% in detecting tuberculous pleurisy, while thorascopic pleural biopsy displayed a similar sensitivity of 90% (χ²=1.05, df=1, p=0.30). The sensitivities of these 2 modalities did not significantly differ based on the degree of pleural thickening (p>0.05). Post-procedural complications were minor. CONCLUSIONS Ultrasound-guided and thoracoscopic pleural biopsy both display strong (>80%) but statistically similar overall diagnostic yields for diagnosing pleural effusions following inconclusive thoracentesis. Both modalities also display strong (>80%) but statistically similar sensitivities in detecting tuberculous pleurisy.

Diagnostic delay in extrapulmonary tuberculosis and impact on patient morbidity: A study from Zanzibar

Background

Early and proper treatment of tuberculosis could have an important impact on the morbidity, mortality and the economic situation of patients. There is insufficient knowledge on the extent of diagnostic delay and the associated factors in extrapulmonary tuberculosis (EPTB). The aims of this study were to assess the health care seeking behaviour, EPTB knowledge and diagnostic delay in presumptive EPTB patients at the main referral hospital in Zanzibar, factors associated with longer delay, and the impact of untreated EPTB on self-rated health.

Materials and methods

Prospective data collection using a semi-structured questionnaire in patients presenting with symptoms suggestive of EPTB. The time between the onset of symptoms and first visit to a health care provider (patient delay), and then to the initiation of treatment (health system delay) and total delay were analysed according to sociodemographic and clinical factors and health care seeking trajectories. The EQ-5D-3L was used among the adult EPTB patients to assess the impact of treatment on self-rated health.

Results

Of the 132 patients with median age of 27 years (interquartile range 8–41), 69 were categorized as TB cases and 63 as non-TB cases. The median patient, health system and total delays were 14, 34 and 62 days respectively, among the EPTB patients. A longer health system delay with repeated visits to the same health care level was reported. Significantly better self-rated health status was described after treatment. The knowledge regarding extrapulmonary disease was low.

Conclusion

Many EPTB patients, presenting to the main referral hospital in Zanzibar, experience a long delay in the initiation of treatment, specially patients with TB lymphadenitis. The health system delay is the major contributor to the total delay. The improvement of self-rated health after treatment implies that timely treatment has the potential to reduce morbidity and the economic loss for the patient.

Assessment of Extrapulmonary Tuberculosis Using Gene Xpert MTB/RIF Assay and Fluorescent Microscopy and Its Risk Factors at Dessie Referral Hospital, Northeast Ethiopia

BACKGROUND

Tuberculosis is a major public health problem and extrapulmonary tuberculosis (EPTB) accounts for a significant proportion of tuberculosis cases worldwide.

OBJECTIVE

To determine the magnitude of EPTB, associated risk factors, and agreement of diagnostic techniques at Dessie Referral Hospital.

METHODS

A cross-sectional study was conducted on consecutive presumptive EPTB cases from March 1 to June 30, 2017. Sociodemographic characteristics and other variables were collected using a structured questionnaire. Clinical specimens were collected and processed using fluorescent microscopy and Gene Xpert assay. Data was analyzed using SPSS version 20. Chi-square test and logistic regression were done and a P value of ≤0.05 was taken as statistically significant.

RESULTS

From a total of 353 presumptive EPTB cases the overall prevalence of Gene Xpert assay and smear confirmed patients was 8.8% and 2.5%, respectively. Tuberculosis lymphadenitis was the predominant (33.3%) type followed by pleural (11.9%) and peritoneal (6.7%) tuberculosis. Previous history of pulmonary tuberculosis was significantly associated with extrapulmonary infection (AOR:2.8; 95%CI: 1.05-7.54; p=0.04); however, other variables such as age, residence, sex, marital status, occupation, level of education, and monthly income did not show any association.

CONCLUSION

High proportions (71%) of Gene Xpert assay confirmed EPTB patients were smear-negative. Sensitivity of microscopy should be enhanced in resource limited countries like Ethiopia where Gene Xpert machine is not easily accessible.

Tuberculous arthritis: negative Xpert MTB/RIF assay does not rule out infection!

We present a case of a 31-year-old man of Indian origin with no previous medical history who presented with an inflamed knee. Treatment for bacterial infection was unsuccessful, and needle aspiration of the left knee effusion/collection was smear and culture positive for tuberculosis (TB), despite Xpert MTB/RIF being falsely negative. The patient was commenced on quadruple therapy for TB and within 2 months had improved significantly with no clinical evidence of ongoing inflammation.

MPT64 antigen detection test improves routine diagnosis of extrapulmonary tuberculosis in a low-resource setting: A study from the tertiary care hospital in Zanzibar

BACKGROUND

Extrapulmonary tuberculosis (EPTB) is a diagnostic challenge. An immunochemistry-based MPT64 antigen detection test (MPT64 test) has reported higher sensitivity in the diagnosis of EPTB compared with conventional methods. The objective of this study was to implement and evaluate the MPT64 test in routine diagnostics in a low-resource setting.

METHODS

Patients with presumptive EPTB were prospectively enrolled at Mnazi Mmoja Hospital, Zanzibar, and followed to the end of treatment. Specimens collected were subjected to routine diagnostics, GeneXpert® MTB/RIF assay and the MPT64 test. The performance of the MPT64 test was assessed using a composite reference standard, defining the patients as tuberculosis (TB) cases or non-TB cases.

RESULTS

Patients (n = 132) were classified as confirmed TB (n = 12), probable TB (n = 34), possible TB (n = 18), non-TB (n = 62) and uncategorized (n = 6) cases. Overall, in comparison to the composite reference standard for diagnosis, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the MPT64 test was 69%, 95%, 94%, 75% and 82%, respectively. The MPT64 test performance was best in TB lymphadenitis cases (n = 67, sensitivity 79%, specificity 97%) and in paediatric TB (n = 41, sensitivity 100%, specificity 96%).

CONCLUSIONS

We show that the MPT64 test can be implemented in routine diagnostics in a low-resource setting and improves the diagnosis of EPTB, especially in TB lymphadenitis and in children.

Cervical tuberculous lymphadenitis: diagnosis and demographics, a five-year case series in the UK

Introduction Cervical tuberculous lymphadenitis is a low-volume condition in the UK with a potential for delayed diagnosis. This study describes typical demographic and clinical features of patients diagnosed with cervical tuberculous lymphadenitis in a UK population. The utility of cytological, histological and microbiological investigations is reviewed with comparison between fine-needle aspiration and open biopsy. This information can facilitate recognition of new cases and guide initial management. Methods Patients diagnosed with cervical tuberculous lymphadenitis between January 2009 and December 2013 at two district general hospitals were identified from local infectious disease databases. Retrospective case-note review was undertaken to collect demographic and diagnostic data and associated complications. Results Full data were available for 51 patients aged 19-70 years (mean 32.4 years) with mean follow-up of 370 days; 49/51 patients were immigrants to the UK with a wide geographic spread in the countries of origin and time since arrival; 42/51 had no significant comorbidities, although two patients had coexistent HIV infection. The clinical presentation was most frequently without constitutional symptoms (39/51) and often with no history of tuberculosis contact. Posterior triangle neck nodes were most commonly involved (26/51). Conclusion The 'typical' patient with cervical tuberculous lymphadenitis in our region is a young healthy individual who came to the UK from a high-risk country several years earlier. Diagnosis by fine-needle aspiration is as effective as open biopsy if fluid/pus is aspirated. Open biopsy is potentially associated with complications but does not appear to increase chronic wound discharge rates in our series.