Acid-fast bacilli culture positivity and drug resistance in abdominal tuberculosis in Mumbai, India

Mistakes to avoid in the management of abdominal tuberculosis

INTRODUCTION

The diagnosis and management of abdominal tuberculosis, i.e Gastrointestinal Tuberculosis (GITB) and tuberculous peritonitis (TBP) is challenging. Abdominal tuberculosis, presenting usually with abdominal pain, intestinal obstruction, and constitutional symptoms, is typically a paucibacillary condition. The diagnosis hinges on a correct interpretation of clinical, radiological, histological, biochemical, and microbiological findings as also appropriately assessing response to therapy.

AREAS COVERED

The authors review potential missteps that could occur in managing GITB and TBP sourced from published literature and clinical experience. These include avoiding excess use of tests with limited accuracy, understanding limitations of ascitic adenosine deaminase (ADA) and granulomas, avoiding empirical antitubercular therapy (ATT) where possible but also understanding that microbiological tests may not always be positive, and finally not to bank solely on subjective clinical responses but to use objective markers in assessing response to therapy. In addition, diagnosis of predisposing immunosuppressed states, attention to nutrition, appropriate management of sequelae with endoscopic dilatation/surgery, and early surgery when indicated are some of the additional issues discussed.

EXPERT OPINION

In future, a more secure diagnosis banking on the use of better microbiological tools, multiparameter-based models, artificial intelligence-based approaches, and use of advances in -omics-based approaches can improve diagnosis and avoid some missteps.

Diagnostic performance of adenosine deaminase for abdominal tuberculosis: A systematic review and meta-analysis

Background and aim

Abdominal tuberculosis (TB) is a common type of extrapulmonary TB with an insidious onset and non-specific symptoms. Adenosine deaminase (ADA) levels increase rapidly in the early stages of abdominal TB. However, it remains unclear whether ADA serves as a diagnostic marker for abdominal TB.

Methods

We performed a systematic literature search for relevant articles published in PubMed, Web of Science, Cochrane Library, and Embase up to April 2022. First, we used the Quality Assessment of Diagnostic Accuracy Studies tool-2 (QUADAS-2), to evaluate the quality of the included articles. Bivariate and hierarchical summary receiver operating characteristic (HSROC) models were then utilized to analyze pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the receiver operating characteristic curve (AUROC). In addition, we explored a subgroup analysis for potential heterogeneity and publication bias among the included literature.

Results

Twenty-four articles (3,044 participants, 3,044 samples) which met the eligibility criteria were included in this study. The pooled sensitivity and specificity of ADA for abdominal TB detection were 93% [95% confidence interval (CI): 0.89-0.95] and 95% (95% CI: 0.93-0.96), respectively. PLR and NLR were 18.6 (95% CI: 14.0-24.6) and 0.08 (95% CI: 0.05-0.12), respectively. DOR and AUROC were 236 (95% CI: 134-415) and 0.98 (95% CI: 0.96-0.99), respectively. Furthermore, no heterogeneity or publication bias was found.

Conclusions

Our meta-analysis found ADA to be of excellent diagnostic value for abdominal TB and could be used as an auxiliary diagnostic tool.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022297931.

Recent updates in diagnosis of abdominal tuberculosis with emphasis on nucleic acid amplification tests

INTRODUCTION

Abdominal tuberculosis (TB) is a common epitome of extrapulmonary TB (EPTB), wherein peritoneal and intestinal TB are the most prevalent forms. Diagnosis of abdominal TB is a daunting challenge owing to variable anatomical locations, paucibacillary nature of specimens and atypical clinical presentations that mimic other abdominal diseases, such as Crohn's disease and malignancies. In this review, we made a comprehensive study on the diagnosis of abdominal TB.

AREA COVERED

Various modalities employed for abdominal TB diagnosis include clinical features, imaging, bacteriological tests (smear/culture), histopathological/cytological observations, interferon-gamma release assays and nucleic acid amplification tests (NAATs). Among NAATs, loop-mediated isothermal amplification assay, PCR, multiplex-PCR, nested PCR, real-time PCR and GeneXpert® MTB/RIF were discussed. Identification of circulating Mycobacterium tuberculosis cell-free DNA by real-time PCR within ascitic fluids is another useful approach.

EXPERT OPINION

Several novel molecular/immunological methods, such as GeneXpert Ultra, aptamer-linked immobilized sorbent assay, immuno-PCR (I-PCR) and nanoparticle-based I-PCR have recently been developed for detecting pulmonary TB and several EPTB types, which may also be explored for abdominal TB diagnosis. Precise and prompt diagnosis of abdominal TB may initiate an early therapy so as to reduce the complications, i.e. abdominal pain, ascites, abdominal distension, intestinal obstruction/perforation, etc., and avoid surgical involvement.Plain Language SummaryAbdominal tuberculosis (TB) is a manifestation of extrapulmonary TB (EPTB), where peritoneal and intestinal TB are two major forms. Diagnosis of abdominal TB is difficult owing to low bacterial load present in clinical samples and non-specific clinical presentations as it mimics other diseases such as inflammatory bowel diseases, abdominal malignancies, etc. Bacteriological tests (smear/culture) almost fail owing to poor sensitivities and it is not always possible to get representative tissue samples for histopathological and cytological observations. In recent years, molecular tests i.e. nucleic acid amplification tests (NAATs), such as PCR/multiplex-PCR (M-PCR), nested PCR and GeneXpert are widely employed. Markedly, PCR/M-PCR and nested PCR exhibited reasonable good sensitivities/specificities, while GeneXpert revealed low sensitivity in most of the studies but high specificity, thus it could assist in differential diagnosis of intestinal TB and Crohn's disease. Further, novel molecular/immunological tests employed for pulmonary TB and other EPTB types were described and those tests can also be utilized to diagnose abdominal TB. Reliable and rapid diagnosis of abdominal TB would initiate an early start of anti-tubercular therapy and reduce the severe complications.

Diagnostic yield of endoscopic ultrasound-guided fine-needle aspiration of tubercular lymphadenitis using combination of cytology and Gene Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) genes

Diagnostic yield of an automated molecular test, Gene Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF), was evaluated in this study to simultaneously detect the MTB gene and resistance to rifampicin (RIF) on cytology samples acquired via endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNAC) in suspected tubercular lymphadenitis. Microscopy, cytology, Gene Xpert MTB/RIF assay data on Acid-fast bacillus (AFB), and traditional culture of lymph nodes were retrospectively analyzed. Thirty-one patients (median age 33.5 years, inter-quartile range [IQR] 21-66, 18, 58% female) presented with fever (28, 90%), dysphagia (2, 7%), and recurrent subacute intestinal obstruction (1, 3%). Gene Xpert showed higher sensitivity (30, 97%) compared to the other tests: cytology (23, 77%; odds ratio [OR] 8.8, 95% confidence interval [CI] 1.0-76.9; p = 0.05), AFB smears (12, 39%; OR 50, 95% CI 5.9-420.4; p = 0.00001), and conventional culture (4, 13%; OR 188.5, 95% CI 19.7-1796.3; p = 0.0000). We conclude that Gene Xpert MTB/RIF test on EUS-guided FNAC samples is very useful to diagnose tubercular lymphadenitis.

An outcome-based composite approach for the diagnosis of intestinal tuberculosis: a pilot study from a tertiary care centre in South India

BACKGROUND

The diagnosis of intestinal TB (ITB) is challenging because of its overlapping features with Crohn's disease. This outcome-based study evaluated the combination of colonoscopy, histopathology, Xpert MTB/RIF and TB culture for best sensitivity and specificity.

METHOD

This was a four-year retrospective, observational study of 426 clinically suspected patients who underwent colonoscopy with biopsies for histopathology, Xpert MTB/RIF and TB culture. ITB was diagnosed using the composite reference standard (CRS), which comprised either histological features or culture or Xpert MTB/RIF positivity, and positive response to anti-tuberculous treatment on follow up.

RESULTS

35 (8.2%) patients were diagnosed with ITB. Histopathology had the highest sensitivity (91.4%) and negative predictive value (99.2%), MTB/RIF had the highest specificity (100%) and positive predictive value (100%). A combinatorial approach with Xpert MTB/RIF and histopathology had optimal diagnostic value (97%), approaching 100% sensitivity with culture. 40% of cases were diagnosed within 12 hours with Xpert MTB/RIF and 97% cases within three days.

CONCLUSION

This combinatorial diagnostic model provides rapid and reliable diagnosis of ITB which may be useful in endemic areas.

Gastrointestinal tuberculosis: A systematic review of epidemiology, presentation, diagnosis and treatment

Tuberculosis (TB) once considered a disease of the developing world is infrequent in the developing world too. Its worldwide prevalence with a huge impact on the healthcare system both in economic and health terms has prompted the World Health Organization to make it a top priority infectious disease. Tuberculous infection of the pulmonary system is the most common form of this disease, however, extrapulmonary TB is being increasingly recognized and more often seen in immunocompromised situations. Gastrointestinal TB is a leading extrapulmonary TB manifestation that can defy diagnosis. Overlap of symptoms with other gastrointestinal diseases and limited accuracy of diagnostic tests demands more awareness of this disease. Untreated gastrointestinal TB can cause significant morbidity leading to prolonged hospitalization and surgery. Prompt diagnosis with early initiation of therapy can avoid this. This timely review discusses the epidemiology, risk factors, pathogenesis, clinical presentation, current diagnostic tools and therapy.

Diagnostic accuracy of the Xpert MTB/RIF assay for abdominal tuberculosis: a systematic review and meta-analysis

BACKGROUND

We performed a meta-analysis to determine diagnostic accuracy of Xpert MTB/RIF for diagnosis of abdominal (intestinal or peritoneal) tuberculosis (TB) in various tissues (intestinal, omental/peritoneal tissue or ascitic fluid).

METHODS

Electronic databases were searched for observational studies on use of Xpert MTB/RIF in ascitic fluid, peritoneal, or omental tissue for diagnosis of peritoneal and intestinal TB. We calculated the pooled sensitivity, specificity and diagnostic odds ratio of Xpert MTB/RIF for diagnosis of peritoneal TB in comparison to composite reference standard (CRS) and culture, and in comparison to CRS for intestinal TB.

RESULTS

Twenty-five observational studies were included. The pooled sensitivity and specificity as assessed with peritoneal culture from ascites as an Index test was 64% (95% Confidence Interval [C.I.] 49-76%) and 97% (95% C.I., 95-99%) respectively and with peritoneal CRS was 30% (95% C.I., 22-40%) and 100% (95% C.I., 98-100%) respectively. In the intestinal group, the pooled sensitivity and specificity of Xpert MTB/RIF was 23% (95% C.I., 16-32%) and 100% (95% C.I., 52-100%). The AUC of peritoneal culture and intestinal tissue was 0.935 and 0.499.

CONCLUSION

Xpert MTB/RIF has modest sensitivity for diagnosis of peritoneal and intestinal tuberculosis but has a good specificity.

PROSPERO REGISTRATION

CRD42020140545.

Challenges in the diagnosis and management of inflammatory bowel disease in resource-limited settings in Asia

Inflammatory bowel disease (IBD) is increasing in prevalence in resource-limited settings in Asia. Although the prevalence of IBD is lower in these settings than in high-income countries, the high disease burden due to large population size is projected to overtake that of high-income countries in the near future. Unique challenges exist for diagnosing and managing IBD in Asia. On one hand, the inadequate disease awareness in physicians and the general population, the scarcity of diagnostic services, the infectious mimics of IBD (specifically intestinal tuberculosis), and the widespread use of empirical antibiotics and antitubercular therapy pose diagnostic challenges. On the other hand, the absence of a centralised health-care delivery system or universal health insurance, the high cost of therapy, limited access to biologics, and the high risk of opportunistic infections with immunosuppressive therapy present therapeutic challenges. The high probability of tuberculosis reactivation often precludes biological therapy because Asia is highly endemic for tuberculosis and has a high prevalence of latent tuberculosis. Current screening strategies are often ineffective in ruling out latent tuberculosis. Hence, management strategies are often modified according to these challenges. This Series paper discusses the challenges in the diagnosis and management of IBD in resource-limited settings in Asia.

Is the rise in Crohn's disease in India accompanied by a fall in intestinal tuberculosis? A single-center experience

INTRODUCTION

The relationship between the incidence of intestinal tuberculosis (TB) and Crohn's disease (CD) is interesting, especially considering the striking similarity between the two conditions. Some studies from Asian populations suggested that the incidence of intestinal TB decreases when there is an increase in CD.

AIM

To compare the incidence trend between intestinal TB and CD over 15 years.

METHODS

Medical records of patients seen in the Division of Gastroenterology over 15 years (2005-2019) were reviewed. CD was diagnosed according to the Copenhagen criteria. Intestinal TB was diagnosed in the appropriate clinical situation if any one or more of the following was present: (1) positive TB MGIT culture; (2) positive Gene Xpert for TB; (3) suggestive histologic findings, with positive tissue acid-fast bacillus (AFB) on smear or with sustained response to anti-TB therapy. The incidence time trend of patients with CD and intestinal TB diagnosis was then studied year-wise.

RESULTS

632 medical case records were accessed; 60 patients were excluded due to inadequate data or not fulfilling diagnostic criteria. The 572 patients included 224 with intestinal TB (median age 37 years, IQR 22; 125 [56%] females) and 348 with CD (median age 40 years, IQR 25; 159 [46%] females [p < 0.02 as compared to TB]). Thus, more patients with CD were seen during the study period, but there was no correlation between the incidence of the two conditions (r = 0.318; p = 0.25).

CONCLUSION

In Indian patients in a single private-sector center, there was no inverse correlation between the incidence of intestinal TB and CD over 15 years.

A systemic review on tuberculosis

Tuberculosis (TB), which is caused by bacteria of the Mycobacterium tuberculosis complex, is one of the oldest diseases known to affect humans and a major cause of death worldwide. Tuberculosis continues to be a huge peril disease against the human population and according to WHO, tuberculosis is a major killer of the human population after HIV/AIDS. Tuberculosis is highly prevalent among the low socioeconomic section of the population and marginalized sections of the community. In India, National strategic plan (2017-2025) has a national goal of elimination of tuberculosis by 2025. It requires increased awareness and understanding of Tuberculosis. In this review article history, taxonomy, epidemiology, histology, immunology, pathogenesis and clinical features of both pulmonary tuberculosis (PTB) and extra-pulmonary tuberculosis (EPTB) has been discussed. A great length of detailed information regarding diagnostic modalities has been explained along with diagnostic algorithm for PTB and EPTB. Treatment regimen for sensitive, drug resistant and extensive drug resistant tuberculosis has been summarized along with newer drugs recommended for multi drug resistant tuberculosis. This review article has been written after extensive literature study in view of better understanding and to increase awareness regarding tuberculosis, as a sincere effort that will help eliminate tuberculosis off the face of the earth in near future.

Abdominal Tuberculosis in Children: Challenges, Uncertainty, and Confusion

The diagnosis of abdominal tuberculosis (TB) is challenging, and the prevalence of abdominal TB in children is likely underestimated. It may present with nonspecific abdominal symptoms and signs, but children who present with pulmonary TB may have additional abdominal subclinical involvement. Diagnosis is specifically challenging because none of the available diagnostic tools provide adequate sensitivity and specificity. In this review, we summarize the best available evidence on abdominal TB in children, covering the epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment. We propose a diagnostic approach that could be followed for symptomatic children. We believe that a combination of investigations could be useful to both aid diagnosis and define the extent of the disease, and we propose that abdominal ultrasound should be used more frequently in children with possible TB and any abdominal symptoms. This neglected disease has received little attention to date, and further research is warranted.

CLINICAL PROFILE, DRUG RESISTANCE PATTERN AND TREATMENT OUTCOMES OF ABDOMINAL TUBERCULOSIS PATIENTS IN WESTERN INDIA

ABSTRACT BACKGROUND: Abdominal tuberculosis is an increasing problem in developing world. OBJECTIVE: The objective of the study was to describe the clinical presentations, drug resistance pattern and treatment outcomes of abdominal tuberculosis in Western India. METHODS: All the cases of abdominal tuberculosis from May 2014 to April 2017, diagnosed on the basis of clinical profile and gross morphological findings at endoscopy, imaging, followed by histology and/or GeneXpert and MGIT culture were included. All patients received antitubercular drug (AKT) therapy according to national protocol. Patients were followed from diagnoses till completion of treatment and various parameters were studied. RESULTS: Out of the 176 patients, 48% were males. Abdominal pain was most common complaint in 83.5%. On colonoscopy terminal ileum and ileocaecal valve were most commonly involved segments. Upper gastrointestinal tract was involved in four patients. Overall ulceronodular lesions were most common followed by ulcerative/nodular lesion. Strictures in bowel were seen in 28 (15.9%) patients with ileocaecal valve being most commonly involved, of which 23 had symptomatic relief with AKT and only three required dilatation. Histopathology showed granuloma in 80.8% cases. MGIT was positive in 43 (35.80%) cases and GeneXpert was positive in 35 (26.1%) cases. Eight patients had multi drug resistant tuberculosis. Only two patients required surgical management. CONCLUSION: Abdominal tuberculosis with wide spectrum of presentation, can still be managed with early diagnosis and treatment even in patients with sub acute intestinal obstruction. Weight gain or resolving symptoms were considered early markers of treatment response. Patients with stricture can become asymptomatic with medical treatment alone.

Making a Positive Diagnosis of Intestinal Tuberculosis with the Aid of New Biologic and Histologic Features: How Far Have We Reached?

Background

The diagnosis of intestinal tuberculosis (TB) and its differentiation from Crohn's disease (CD) remain a challenge. We review here in detail the various methods for the diagnosis of intestinal TB.

Summary

Colonoscopy findings in intestinal TB are useful and suggestive; histopathology of colonoscopic biopsies is contributory but rarely confirmatory. Increasing the number of colonoscopic biopsies increases the histological yield. Recent culture methods that have improved the yield for TB offer hope. Mycobacteria Growth Indicator Tube (MGIT) culture is now the standard of care as its yield is superior to that of the traditional Lowenstein-Jensen medium. Increasing the number of colonoscopic biopsy samples for MGIT culture can increase the yield. The culture and histology are complimentary. Even then a significant proportion of patients do not have a positive diagnosis of intestinal TB. Scoring systems have been developed with a sensitivity and specificity of 90 and 60%, respectively, but their utility in routine practice is yet to be established. Similarly, the ratio of visceral fat to total fat is helpful in differentiating CD from intestinal TB. Polymerase chain reaction has been used but its value seems uncertain. Gene Xpert® in an emerging technique that has been found to be useful in the diagnosis of pulmonary TB, and its utility in intestinal TB needs to be looked at. Newer technologies like TB-LAMP (loop-mediated isothermal amplification) need to be assessed in clinical studies.

Key Message

Optimization of the present diagnostic tools (taking an adequate number of biopsies for histology and culture) and study of newer techniques to learn their actual utility seems to be the way forward.

Differentiating Crohn's disease from intestinal tuberculosis

Differentiating Crohn's disease (CD) and intestinal tuberculosis (ITB) has remained a dilemma for most of the clinicians in the developing world, which are endemic for ITB, and where the disease burden of inflammatory bowel disease is on the rise. Although, there are certain clinical (diarrhea/hematochezia/perianal disease common in CD; fever/night sweats common in ITB), endoscopic (longitudinal/aphthous ulcers common in CD; transverse ulcers/patulous ileocaecal valve common in ITB), histologic (caseating/confluent/large granuloma common in ITB; microgranuloma common in CD), microbiologic (positive stain/culture for acid fast-bacillus in ITB), radiologic (long segment involvement/comb sign/skip lesions common in CD; necrotic lymph node/contiguous ileocaecal involvement common in ITB), and serologic differences between CD and ITB, the only exclusive features are caseation necrosis on biopsy, positive smear for acid-fast bacillus (AFB) and/or AFB culture, and necrotic lymph node on cross-sectional imaging in ITB. However, these exclusive features are limited by poor sensitivity, and this has led to the development of multiple multi-parametric predictive models. These models are also limited by complex formulae, small sample size and lack of validation across other populations. Several new parameters have come up including the latest Bayesian meta-analysis, enumeration of peripheral blood T-regulatory cells, and updated computed tomography based predictive score. However, therapeutic anti-tubercular therapy (ATT) trial, and subsequent clinical and endoscopic response to ATT is still required in a significant proportion of patients to establish the diagnosis. Therapeutic ATT trial is associated with a delay in the diagnosis of CD, and there is a need for better modalities for improved differentiation and reduction in the need for ATT trial.

Do additional colonoscopic biopsies increase the yield of Mycobacterium tuberculosis culture in suspected ileo-colonic tuberculosis?

BACKGROUND

Isolation of Mycobacterium tuberculosis on culture is vital for differentiating intestinal tuberculosis (ITB) from Crohn's disease (when histology is not diagnostic) and for diagnosis of multidrug-resistant tuberculosis. The current yield of TB culture (< 50%) from colonoscopic biopsy tissue is not satisfactory.

AIM

To determine whether more colonoscopic biopsies can increase the yield of TB culture in patients with ITB.

METHODS

In this prospective study, in patients who underwent colonoscopy for suspected ITB, four biopsies were taken (container 1) followed by an additional four biopsies (container 2) for TB culture, from involved regions. The culture was done using Mycobacterium Growth Indicator Tube (MGIT) 960. A final diagnosis of ITB was made if TB culture was positive, there was unequivocal histological evidence of TB, or there was unequivocal evidence of TB elsewhere in the body, in the absence of another diagnosis.

RESULTS

Of 182 patients enrolled (mean age 37.5 [SD 17.2] years; 93 [51.5%] women), 70 (38.4%) were finally diagnosed to have ITB. MGIT culture was positive in 29 (41.4%), 27 (38.5%), and 37 (52.8%) of 70 patients from containers 1, container 2, and combined eight biopsies, respectively. The incremental yield of eight biopsies was 11.4% (95% confidence interval [CI] 5.1 to 21.3%) as compared to container 1 and 14.3% (95% CI 7.1 to 24.7%) as compared to container 2.

CONCLUSION

Additional four (total eight) colonoscopic biopsies improved the yield of TB culture positivity over four biopsies by 11.4% to 14.3%, to 52.8%; this increase is clinically useful.

Drug resistance in intestinal tuberculosis: A reason to worry?

Background and Aim

Emergence of drug resistance in intestinal tuberculosis (ITB) makes the treatment of this condition challenging. While there is growing evidence of multiple and extensive drug resistance in pulmonary and glandular tuberculosis (TB), literature regarding susceptibility and resistance patterns in ITB is scarce. The aim of the current paper was to study the prevalence of drug resistance in patients with ITB.

Methods

Among patients presenting to a tertiary care hospital in Mumbai between 2008 and 2016, records of all patients with ITB, whose mucosal biopsy (obtained at ileocolonoscopy) tissue culture was positive for Mycobacterium tuberculosis and in whom drug sensitivity testing was performed, were retrospectively analyzed. Sensitivity and resistance to single or multiple anti-TB drugs were noted.

Results

A total of 43 patients were included, of whom 10 (23.2%) patients were diagnosed to have resistance to at least one first-line anti-TB drug. Resistance to isoniazid was the most common (nine patients), followed by rifampicin (six), pyrazinamide (five), streptomycin and ethionamide (four each), ethambutol, moxifloxacin and ofloxacin (three each), and p-amino salicylic acid (one). Six patients (13.9%) had multidrug-resistant TB and needed second-line anti-TB therapy as per drug sensitivity pattern. There was no patient with extensive drug-resistant TB.

Conclusion

Twenty-three percent of our patients with ITB tested for drug resistance had drug resistance, 13.9% being multidrug resistant and needing second-line anti-TB therapy.

Intestinal tuberculosis: a diagnostic challenge

OBJECTIVE

To describe characteristics, presentation, time to diagnosis and diagnostic findings of patients with intestinal tuberculosis (ITB) in a low-burden country.

METHOD

Retrospective study of 61 consecutive ITB patients diagnosed between 2008 and 2014 at a large East London hospital.

RESULTS

Forty of sixty-one patients were male. Mean age was 34.6 years. 93% of patients were born abroad, mostly from TB-endemic areas (Indian subcontinent: 88%, Africa: 9%). 25% had concomitant pulmonary TB. Median time from symptom onset to ITB diagnosis was 13 weeks (IQR 3-26 weeks). Ten patients were initially treated for IBD, although patients had ITB. The main sites of ITB involvement were the ileocaecum (44%) or small bowel (34%). Five patients had isolated perianal disease. Colonoscopy confirmed a diagnosis of ITB in 77% of those performed. 42 of 61 patients had a diagnosis of ITB confirmed on positive histology and/or microbiology.

CONCLUSION

Diagnosis of ITB is often delayed, which may result in significant morbidity. ITB should be excluded in patients with abdominal complaints who come from TB-endemic areas to establish prompt diagnosis and treatment. Diagnosis is challenging but aided by axial imaging, colonoscopy and tissue biopsy for TB culture and histology.

Evaluation of Xpert MTB/RIF assay performance in the diagnosis of abdominal tuberculosis

BACKGROUND/AIMS

The use of genetic probes for the diagnosis of pulmonary tuberculosis (TB) has been well described. However, the role of these assays in the diagnosis of intestinal tuberculosis is unclear. We therefore assessed the diagnostic utility of the Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay, and estimated the prevalence of multidrug-resistant (MDR) TB in the Indian population.

METHODS

Of 99 patients recruited, 37 had intestinal TB; two control groups comprised 43 with Crohn's disease (CD) and 19 with irritable bowel syndrome. Colonoscopy was performed before starting any therapy; mucosal biopsies were subjected to histopathology, acid-fast bacilli staining, Lowenstein-Jensen culture, and nucleic acid amplification testing using the Xpert MTB/RIF assay. Patients were followed up for 6 months to confirm the diagnosis and response to therapy. A composite reference standard was used for diagnosis of TB and assessment of the diagnostic utility of the Xpert MTB/RIF assay.

RESULTS

Of 37 intestinal TB patients, the Xpert MTB/RIF assay was positive in three of 37 (8.1%), but none had MDR-TB. The sensitivity, specificity, positive predictive value, and negative predictive value of the Xpert MTB/RIF assay was 8.1%, 100%, 100%, and, 64.2%, respectively.

CONCLUSIONS

The Xpert MTB/RIF assay has low sensitivity but high specificity for intestinal TB, and may be helpful in endemic tuberculosis areas, when clinicians are faced with difficulty differentiating TB and CD. Based on the Xpert MTB/RIF assay, the prevalence of intestinal MDR-TB is low in the Indian population.

Extrapulmonary tuberculosis among females in South Asia-gap analysis

The percentage of extrapulmonary tuberculosis (EPTB) among new and relapse tuberculosis cases in South Asia (Afghanistan, Pakistan, India, and Bangladesh) ranged from 19% to 23% in 2014. While tuberculosis was reportedly more prevalent in males, a higher preponderance of EPTB was observed in females. National tuberculosis control programs are highly focused on pulmonary tuberculosis. This creates gaps in the surveillance, diagnosis, and study of EPTB among females, which is especially pronounced in the South Asian setting. We have reviewed recently published literatures from January 2010 to June 2016 reporting EPTB in females with a view to evaluate the current epidemiology, risk factors, diagnostic modalities, and treatment outcomes. We report significant gaps in the surveillance of EPTB among women in South Asia, emphasizing the need for greater focus on EPTB in females to overcome current surveillance and knowledge gaps.

Hepatic and Intra-abdominal Tuberculosis: 2016 Update

Mycobacterium tuberculosis (TB) infection affects nearly 10 million people a year and causes 1.5 million deaths. TB is common in the immunosuppressed population with 12 % of all new diagnoses occurring in human immune deficiency virus (HIV)-positive patients. Extra-pulmonary TB occurs in 12 % of patients with active TB infection of which 3.5 % is hepatobiliary and 6-38 % is intra-abdominal. Hepatobiliary and intra-abdominal TB can present with a myriad of non-specific symptoms, and therefore, diagnosis requires a high level of suspicion. Accurate and rapid diagnosis requires a multidisciplinary team (MDT) approach using radiology, interventional radiology, surgery and pathology services. Treatment of TB is predominantly medical, yet surgery plays an important role in managing the complications of hepatobiliary and intra-abdominal TB.

Epidemiological perspective of drug resistant extrapulmonary tuberculosis

Tuberculosis (TB) remains one of the leading infectious diseases causing significant morbidity and mortality worldwide. Although, pulmonary TB is the most common presentation and is the main transmissible form of the disease, extrapulmonary TB also significantly contributes to the burden of disease and can cause severe complications and disabilities. At present, the most serious issue with TB control programme is emergence of multi and extensively drug resistant Mycobacterium tuberculosis strain world-wide. As the number of drug resistant pulmonary TB is increasing around the world, the number of drug resistant TB with extrapulmonary manifestations are also on rise. However, there is surprisingly scant information in medical literatures on prevalence and impact of extrapulmonary drug-resistant TB. Here, we appraise the recent epidemiological studies that underpin the status and impact of drug resistance in TB cases with extrapulmonary manifestations.