GeneXpert MTB/RIF Assay for the Diagnosis of Tuberculous Lymphadenitis on Concentrated Fine Needle Aspirates in High Tuberculosis Burden Settings

Cytomorphological patterns and clinical features of presumptive tubercular lymphadenitis patients and their comparison with bacteriological detection methods: a cross-sectional study

INTRODUCTION

Tuberculous lymphadenitis (TBLN) is an infection of the lymph node caused by Mycobacterium tuberculosis. Histological diagnoses of presumptive patients are often accompanied by cytomorphological features. However, the sensitivities of these features are often precluded by the variable degrees of narrative similarities compared to other diagnostic modalities.

OBJECTIVE

The aim of this study was to investigate and compare the cytomorphological and clinical features of presumptive TBLN patients with bacteriological detection methods.

METHODS

A similar cohort of TBLN patients from our previous study who were enrolled prospectively from the ALERT Specialized Hospital, Addis Ababa, Ethiopia, was considered for this analysis. SPSS version 26 was used for data analysis. Descriptive analysis was conducted to characterize the study population using the independent variable and presented with frequency tables. The chi-square test was used to measure the association. A P-value of < 0.05 was considered statistically significant.

RESULTS

Using FNAC, 60/126 (47.6%) of the participants were reported to have features consistent with TB. Of the total FNAC-positive cases, many (30/60 and 27/60) showed pattern B (caseous necrosis only) and pattern C (epithelioid granuloma with caseous necrosis), respectively. Strong concordance was observed in Pattern A (abundant caseous necrosis with few epithelioid macrophages) followed by patterns B and C with GeneXpert and MGIT culture (P value < 0.001). Night sweats and alcohol intake were shown to correlate with positive cases as reported by FNAC (P value = 0.008 respectively), GeneXpert (P value = 0.02 & 0.001), and culture methods (P-value = < 0.001 & 0.002).

CONCLUSION

Cytomorphological features, particularly patterns A, B, and C, could be considered in the diagnosis of TBLN given their comparable outcomes with bacteriological detection methods. On another note, we recommend that due care and attention be given when treating TBLN patients based solely on clinical presentation, as these diagnostics may be prone to false results, leading to inappropriate administration of anti-TB drugs and other consequences.

The Performance of GeneXpert in the Diagnosis of Lymph Node Tuberculosis: A Prospective Study Comparing GeneXpert and Culture Findings

Background and objective Lymph node tuberculosis (LNTB) is a common manifestation of extrapulmonary tuberculosis (EPTB). GeneXpert is a rapid diagnostic molecular test that simultaneously detects tuberculosis and rifampicin (RIF) resistance. In this study, we aimed to assess the epidemiology of LNTB and diagnostic performance parameters of the GeneXpert in routine ENT practice. Methods We conducted a cross-sectional prospective study from January to July 2019, in the Department of Otorhinolaryngology and Head Neck Surgery at the Hassan II University Hospital Center of Fez, Morocco. The samples were collected using lymph node biopsy and subjected to GeneXpert assay, culture, and histopathology. Diagnostic performance parameters of the GeneXpert were calculated and compared with culture. Results All patients with cervical adenopathy were included. Lymph node biopsies were performed for all patients. The performance of the GeneXpert was assessed according to culture findings. Among the 75 cases, the mean age was 21.6 ± 12.7 years with a female predominance (60%). GeneXpert was positive in 66.7% of specimens. The sensitivity and specificity of the GeneXpert assay were 78.6% and 40.4% respectively. GeneXpert accuracy was 54.6%. The positive predictive value (PPV) and negative predictive value (NPV) were found to be 44% (95% CI: 30.2-57.8) and 76% (95% CI: 59.3-92.7) respectively. Mycobacterium bovis was isolated in all samples, with no case of resistance to RIF found. Conclusions The performance of GeneXpert was found to be superior in terms of establishing the diagnosis of LNTB. It offers speedy and prompt results and clinicians should adopt it in routine clinical practice.

Point-of-care ultrasound for tuberculosis and HIV-revisiting the focused assessment with sonography for HIV-associated tuberculosis (FASH) protocol and its differential diagnoses

BACKGROUND

The 'Focused assessment with sonography for HIV-associated tuberculosis' (FASH) protocol has been applied and researched for over a decade in HIV-infected patients with suspected extra-pulmonary tuberculosis. Interpretation of target FASH features may be challenging as they can also indicate alternative opportunistic diseases.

OBJECTIVES

The primary aim of the review was summarizing the accumulated evidence on the diagnostic accuracy of the FASH protocol including description of diagnoses of target FASH features.

SOURCES

Literature was searched using PubMed, Google Scholar, and publications referencing the original FASH publications; data from identified studies were compiled with data from studies identified by a preceding Cochrane review. A meta-analysis was performed based on a generalized linearized mixed model. Data on differential diagnoses were compiled by literature review and retrospective evaluation of clinical data.

CONTENT

We identified ten studies; abdominal target FASH features were most studied. Sensitivity and specificity estimates were 39% (95% CI 25-54) and 89% (95% CI 83-96) for enlarged lymph nodes (ten studies), and 30% (95% CI 16-45%) and 93% (95% CI 89-98%) for hypoechoic spleen lesions (eight studies). In people living with HIV differential diagnoses of target FASH features are multiple and primarily include other opportunistic infections and malignancies such as non-tuberculous mycobacterial infection, bacillary angiomatosis, hepato-splenic brucellosis, meliodiosis, visceral leishmaniasis, invasive fungal infections, and lymphoma as well as Kaposi sarcoma. Ultrasound-guided diagnostic sampling may assist obtention of a definitive diagnosis.

IMPLICATIONS

On the basis of current evidence, although limited by methodology, and personal experience, we recommend basic ultrasound training, including the FASH protocol and ultrasound-guided diagnostic interventions, for all healthcare providers working with people living with HIV in resource-limited settings.

Value of ultrasound guided biopsy combined with Xpert Mycobacterium tuberculosis/resistance to rifampin assay in the diagnosis of chest wall tuberculosis

BACKGROUND

The thoracic wall lesions, particularly chest wall tuberculosis, and chest wall tumors and other pyogenic wall and actinomycetes infections, almost always present as a diagnostic challenge.

AIM

To explore the value of ultrasound-guided biopsy combined with the Xpert Mycobacterium tuberculosis/resistance to rifampin (MTB/RIF) assay to diagnose chest wall tuberculosis.

METHODS

We performed a retrospective study of patients with chest wall lesions from March 2018 to March 2021. All patients received the ultrasound-guided biopsy for pathology examination, acid-fast Bacillus staining, mycobacterial culture, and Xpert MTB/RIF analysis. The sensitivity, specificity, and area under the curve (AUC) were calculated for these diagnostic tests, either individually or combined. Rifampicin resistance results were compared between the mycobacterial culture and the Xpert MTB/RIF assay.

RESULTS

In 31 patients with the chest wall lesion biopsy, 22 patients were diagnosed with chest wall tuberculosis. Of them, 3, 6, and 21 patients tested positive for mycobacterial culture, acid-fast stain, and Xpert MTB/RIF assay, respectively. The rifampicin resistance results of the 3 culture-positive patients were consistent with their Xpert MTB/RIF assay results. When considering the sensitivity, specificity, and AUC value, the Xpert MTB/RIF assay (95.5%, 88.9%, and 0.92, respectively) was a better choice than the acid-fast Bacillus stain (27.3%, 100.0%, and 0.64, respectively) and mycobacterial culture (13.6%, 100.0%, 0.57, respectively). No complications were reported during the procedure.

CONCLUSION

Ultrasound guided biopsy combined with Xpert MTB/RIF has high value in the diagnosis of chest wall tuberculosis, and can also detect rifampicin resistance.

Bacteriologically confirmed extrapulmonary tuberculosis and the associated risk factors among extrapulmonary tuberculosis suspected patients in Ethiopia: A systematic review and meta-analysis

BACKGROUND

The actual burden of bacteriologically confirmed extrapulmonary tuberculosis (EPTB) and risk factors in Ethiopia is not well known due to the lack of a strong surveillance system in Ethiopia. Thus, this study was conducted to estimate the pooled prevalence of bacteriologically confirmed EPTB and the associated risk factors among persons suspected to have non-respiratory tuberculosis in Ethiopia.

METHODS

A systematic review and meta-analysis of published studies reporting the prevalence of EPTB from searched electronic databases; Science Direct, PubMed, and Google Scholar was estimated spread across the research periods, nationally, and in different areas, using a fixed-effects model. We used I2 to analyze heterogeneity in the reported prevalence of bacteriologically confirmed extrapulmonary tuberculosis.

RESULTS

After reviewing 938 research articles, 20 studies (19 cross-sectional and 1 retrospective) from 2003 to 2021 were included in the final analyses. The pooled prevalence of bacteriologically confirmed EPTB was 43% (95%CI; 0.34-0.52, I2 = 98.45%). The asymmetry of the funnel plot revealed the presence of publication bias. Specifically the pooled prevalence of bacteriologically confirmed EPTB based on smear microscopy, Xpert MTB/RIF assay, and culture were 22% (95%CI; 0.13-0.30, I2 = 98.56%), 39% (95%CI; 0.23-0.54, I2 = 98.73%) and 49% (95%CI; 0.41-0.57, I2 = 96.43%) respectively. In this study, a history of pulmonary tuberculosis (PTB) contact with PTB patients, contact with live animals, consumption of raw milk, HIV-positive, male, and lower monthly income, were found to be independently associated with bacteriologically confirmed EPTB.

CONCLUSION

Ethiopia has a high rate of bacteriologically confirmed EPTB. A history of previous PTB, being HIV-positive and having contact with PTB patients were the most reported risk factors for EPTB in the majority of studies. Strengthening laboratory services for EPTB diagnosis should be given priority to diagnose EPTB cases as early as possible.

The Value of GeneXpert MTB/RIF for Detection in Tuberculosis: A Bibliometrics-Based Analysis and Review

With the continuous development of medical science and technology, especially with the advent of the era of precision diagnosis and treatment, molecular biology detection technology is widely valued and applied as an aid to early diagnosis of tuberculosis. The GeneXpert Mycobacterium tuberculosis Branching (MTB) technology is a suite of semi-nested real-time fluorescent quantitative PCR in vitro diagnostic technologies developed by Cepheid Inc. It targets the rifampicin resistance gene, rpoB, and can detect both MTB and resistance to rifampicin within 2 h. This review analyzed the papers related to GeneXpert using bibliometric software CiteSpace and Bibliometrix. A total of 151 articles were analyzed, spanning from 2011 to 2021. This bibliometrics-based review summarizes the history of the development of GeneXpert in tuberculosis diagnosis and its current status. Contributions of different countries to the topic, journal analysis, key paper analysis, and clustering of keywords were used to analyze this topic.

Xpert MTB/RIF Ultra assay for tuberculosis disease and rifampicin resistance in children

BACKGROUND

Every year, an estimated one million children and young adolescents become ill with tuberculosis, and around 226,000 of those children die. Xpert MTB/RIF Ultra (Xpert Ultra) is a molecular World Health Organization (WHO)-recommended rapid diagnostic test that simultaneously detects Mycobacterium tuberculosis complex and rifampicin resistance. We previously published a Cochrane Review 'Xpert MTB/RIF and Xpert MTB/RIF Ultra assays for tuberculosis disease and rifampicin resistance in children'. The current review updates evidence on the diagnostic accuracy of Xpert Ultra in children presumed to have tuberculosis disease. Parts of this review update informed the 2022 WHO updated guidance on management of tuberculosis in children and adolescents.

OBJECTIVES

To assess the diagnostic accuracy of Xpert Ultra for detecting: pulmonary tuberculosis, tuberculous meningitis, lymph node tuberculosis, and rifampicin resistance, in children with presumed tuberculosis. Secondary objectives To investigate potential sources of heterogeneity in accuracy estimates. For detection of tuberculosis, we considered age, comorbidity (HIV, severe pneumonia, and severe malnutrition), and specimen type as potential sources. To summarize the frequency of Xpert Ultra trace results.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, three other databases, and three trial registers without language restrictions to 9 March 2021.

SELECTION CRITERIA

Cross-sectional and cohort studies and randomized trials that evaluated Xpert Ultra in HIV-positive and HIV-negative children under 15 years of age. We included ongoing studies that helped us address the review objectives. We included studies evaluating sputum, gastric, stool, or nasopharyngeal specimens (pulmonary tuberculosis), cerebrospinal fluid (tuberculous meningitis), and fine needle aspirate or surgical biopsy tissue (lymph node tuberculosis). For detecting tuberculosis, reference standards were microbiological (culture) or composite reference standard; for stool, we also included Xpert Ultra performed on a routine respiratory specimen. For detecting rifampicin resistance, reference standards were drug susceptibility testing or MTBDRplus.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and, using QUADAS-2, assessed methodological quality judging risk of bias separately for each target condition and reference standard. For each target condition, we used the bivariate model to estimate summary sensitivity and specificity with 95% confidence intervals (CIs). We stratified all analyses by type of reference standard. We summarized the frequency of Xpert Ultra trace results; trace represents detection of a very low quantity of Mycobacterium tuberculosis DNA. We assessed certainty of evidence using GRADE.

MAIN RESULTS

We identified 14 studies (11 new studies since the previous review). For detection of pulmonary tuberculosis, 335 data sets (25,937 participants) were available for analysis. We did not identify any studies that evaluated Xpert Ultra accuracy for tuberculous meningitis or lymph node tuberculosis. Three studies evaluated Xpert Ultra for detection of rifampicin resistance. Ten studies (71%) took place in countries with a high tuberculosis burden based on WHO classification. Overall, risk of bias was low. Detection of pulmonary tuberculosis Sputum, 5 studies Xpert Ultra summary sensitivity verified by culture was 75.3% (95% CI 64.3 to 83.8; 127 participants; high-certainty evidence), and specificity was 97.1% (95% CI 94.7 to 98.5; 1054 participants; high-certainty evidence). Gastric aspirate, 7 studies Xpert Ultra summary sensitivity verified by culture was 70.4% (95% CI 53.9 to 82.9; 120 participants; moderate-certainty evidence), and specificity was 94.1% (95% CI 84.8 to 97.8; 870 participants; moderate-certainty evidence). Stool, 6 studies Xpert Ultra summary sensitivity verified by culture was 56.1% (95% CI 39.1 to 71.7; 200 participants; moderate-certainty evidence), and specificity was 98.0% (95% CI 93.3 to 99.4; 1232 participants; high certainty-evidence). Nasopharyngeal aspirate, 4 studies Xpert Ultra summary sensitivity verified by culture was 43.7% (95% CI 26.7 to 62.2; 46 participants; very low-certainty evidence), and specificity was 97.5% (95% CI 93.6 to 99.0; 489 participants; high-certainty evidence). Xpert Ultra sensitivity was lower against a composite than a culture reference standard for all specimen types other than nasopharyngeal aspirate, while specificity was similar against both reference standards. Interpretation of results In theory, for a population of 1000 children: • where 100 have pulmonary tuberculosis in sputum (by culture): - 101 would be Xpert Ultra-positive, and of these, 26 (26%) would not have pulmonary tuberculosis (false positive); and - 899 would be Xpert Ultra-negative, and of these, 25 (3%) would have tuberculosis (false negative). • where 100 have pulmonary tuberculosis in gastric aspirate (by culture): - 123 would be Xpert Ultra-positive, and of these, 53 (43%) would not have pulmonary tuberculosis (false positive); and - 877 would be Xpert Ultra-negative, and of these, 30 (3%) would have tuberculosis (false negative). • where 100 have pulmonary tuberculosis in stool (by culture): - 74 would be Xpert Ultra-positive, and of these, 18 (24%) would not have pulmonary tuberculosis (false positive); and - 926 would be Xpert Ultra-negative, and of these, 44 (5%) would have tuberculosis (false negative). • where 100 have pulmonary tuberculosis in nasopharyngeal aspirate (by culture): - 66 would be Xpert Ultra-positive, and of these, 22 (33%) would not have pulmonary tuberculosis (false positive); and - 934 would be Xpert Ultra-negative, and of these, 56 (6%) would have tuberculosis (false negative). Detection of rifampicin resistance Xpert Ultra sensitivity was 100% (3 studies, 3 participants; very low-certainty evidence), and specificity range was 97% to 100% (3 studies, 128 participants; low-certainty evidence). Trace results Xpert Ultra trace results, regarded as positive in children by WHO standards, were common. Xpert Ultra specificity remained high in children, despite the frequency of trace results.

AUTHORS' CONCLUSIONS

We found Xpert Ultra sensitivity to vary by specimen type, with sputum having the highest sensitivity, followed by gastric aspirate and stool. Nasopharyngeal aspirate had the lowest sensitivity. Xpert Ultra specificity was high against both microbiological and composite reference standards. However, the evidence base is still limited, and findings may be imprecise and vary by study setting. Although we found Xpert Ultra accurate for detection of rifampicin resistance, results were based on a very small number of studies that included only three children with rifampicin resistance. Therefore, findings should be interpreted with caution. Our findings provide support for the use of Xpert Ultra as an initial rapid molecular diagnostic in children being evaluated for tuberculosis.

Role of GeneXpert MTB/RIF assay for the diagnosis of cervical lymph node tuberculosis and rifampicin resistance

Objectives

Tuberculosis (TB) of lymph node (TB lymphadenitis) is one of the most common forms of extrapulmonary TB (EPTB) whose diagnosis is critically challenging. Although new diagnostic methods have been developed, especially in patients without a history of TB, the cervical tuberculous lymphadenitis diagnosis is still elusive. This study assessed the applicability of GeneXpert in early diagnosis of EPTB, especially cervical lymphadenopathy.

Materials and Methods

The study was conducted in a tertiary care hospital from January 2018 to December 2020 at the department of microbiology. All the samples of cervical lymph node tissue and lymph node aspirate were followed as per the routine protocol for mycobacterial identification. The sample was divided into two parts: one was used for the new molecular-based GeneXpert MTB/RIF assay and the second one was tested by direct and concentrated acid-fast bacilli microscopy by Z-N staining and culture for the detection of MTB.

Results

Among the 145 samples tested, the GeneXpert detected the DNA of MTB in 89 samples (61.37%), whereas the culture test was positive in 42 (28.93%) specimens. GeneXpert also detected 7 rifampicin resistance cases. GeneXpert sensitivity and specificity results were assessed according to culture results. The sensitivity and specificity of the GeneXpert assay were 85.71% and 48.54%, respectively.

Conclusion

GeneXpert MTB/RIF should be used in conjunction with clinical presentation and other molecular investigation in nonrespiratory specimens.

Combination method for the diagnosis of Tuberculous lymphadenitis in high burden settings

Background

India reports the highest number of extrapulmonary tuberculosis (EPTB) cases globally, most of which are lymph node TB (LNTB). In high tuberculosis (TB) burden countries rapid diagnosis is very important. Fine needle aspirate cytology (FNAC) diagnosis can be made with features of caseous necrosis with/without epithelioid granulomas. However, bacteriological confirmation is essential. This study was performed to evaluate the performance of the diagnostic tests available namely FNAC, GeneXpert (GX) and Ziehl Neelsen stain (ZN) stain at resource restricted settings, for LNTB.

Methods

FNAC samples from affected lymph nodes were collected from 100 consenting patients with clinically suspected LNTB. FNA material was analyzed by cytomorphology, ZN and GX. If no Mycobacterium tuberculosis (MTB) was detected, repeat aspirate was cultured on Lowenstein Jensen medium. Descriptive statistical analysis was performed.

Results

Out of 100 cases, 73% showed cytological features consistent with TB. The most common cytomorphological pattern was epithelioid cell granulomas with caseous necrosis (59%). Caseous necrosis only pattern was seen in 14%. MTB was detected in 34% by ZN and 60% by GX. Overall, the combination of FNAC, ZN, GX detected 85% of LNTB.

Conclusions

A combination of FNAC, ZN and GX is a practical tool that can improve and quicken the diagnosis of LNTB in resource restricted high-burden settings.

Integration of cytopathology with molecular tests to improve the lab diagnosis for TBLN suspected patients

Background

Tuberculosis lymphadenitis (TBLN) diagnosis is often challenging in most resource poor settings. Often cytopathologic diagnosis of TBLN suspected patients is inconclusive impeding timely clinical management of TBLN suspected patients, further exposing suspected patients either for unnecessary use of antibiotics or empirical treatment. This may lead to inappropriate treatment outcome or more suffering of suspected patients from the disease. In this study, an integrated diagnostic approach has been evaluated to elucidate its utility in the identification of TBLN suspected patients.

Methods

A cross-sectional study was conducted on 96 clinically diagnosed TBLN suspected patients, where fine needle aspirate (FNA) samples were collected at the time of diagnosis. FNA cytology, Ziehl-Neelsen (ZN), Auramine O (AO) staining, GeneXpert MTB/RIF and Real time PCR (RT-PCR) were performed on concentrated FNA samples. Considering culture as a gold standard, the sensitivity, specificity, positive and negative predictive values were calculated. Cohen’s Kappa value was used to measure interrater variability and level of agreement and a P-value of <0.05 was considered as statistically significant.

Result

Out of the 96 FNA sample, 12 (12.5%) were identified to have Mycobacterium tuberculosis (Mtb) using ZN staining, 27 (28.1%) using AO staining, 51 (53.2%) using FNAC, 43 (44.7%) using GeneXpert MTB/RIF, 51 (53.1%) using Real time PCR (RT-PCR) and 36 (37.5%) using Lowenstein-Jensen (LJ) culture. Compared to LJ culture, the sensitivities of GeneXpert MTB/RIF, RT-PCR, and FNAC were 91.7%, 97.2%, and 97.2%, respectively and the specificities were 83.3%, 73.3%, and 68.3%, respectively. GeneXpert MTB/RIF and RT-PCR when combined with FNAC detected 61 (63.5%) cases as having Mtb, and the sensitivity and specificity was 100% and 58.3%, respectively.

Conclusion

FNA cytology and RT-PCR detected more TBLN cases compared to other Mtb detection tools and the detection sensitivity even improved when FNA cytology was combined with GeneXpert MTB/RIF, performed on concentrated FNA sample, suggesting the combined tests as an alternative approach for improved diagnosis of TBLN.

Detection of Mycobacterium tuberculosis and rifampicin resistance by Xpert® MTB/RIF assay among presumptive tuberculosis cases at Jimma University Medical Center, Southwest Ethiopia

Background

Rapid diagnosis of tuberculosis (TB) and detection of drug resistance are very important for timely and appropriate management of patients. Xpert MTB/RIF assay is approved for use in TB and rifampicin-resistance diagnosis. However, data are limited on the impact of Xpert MTB/RIF assay under routine clinical settings with a heterogeneous group of patients and sample types in Ethiopia.

Methods

A retrospective study was carried out in 2220 presumptive TB cases at Jimma University Medical Center. Data were gathered from the registration logbook using formatted data extraction tools and double entered to epidata version 3.1 and further transported to SPSS version 20 for analysis. Associations were determined using the Chi-square test and P-value <0.05 was considered statistically significant.

Results

Of 2220 cases enrolled, 1665 (75%) were adults and the remaining 555 (25%) were children aged less than 14 years. The majority, 1964 (88.46%), had pulmonary manifestation and 256 (11.54%) had extrapulmonary involvements. The overall, frequency of Mycobacterium tuberculosis (MTB) was 9.3% (206/2220), among this 10.27% (171/1665) and 6.3% (35/555) were adults and children, respectively. M. tuberculosis was detected from 171 (8.75%) of pulmonary patients and 35 (13.28%) of extrapulmonary manifested patients. Out of 206 M. tuberculosis positive cases, 7(3.4%) were rifampicin-resistant: four from pulmonary tuberculosis (PTB) patients and three from EPTB patients. In the Chi-square test, the age group of 15–24 years, previous history of TB, pus/lymph node sample, and being HIV positive were significantly associated with TB positivity by Xpert MTB/RIF (P-value <0.001).

Conclusion

These data suggest that the overall frequency of M. tuberculosis and rifampicin resistance was found to be relatively low compared to the previous reports in Ethiopia. Nevertheless, better diagnostic tools and approaches are still vital to halt the burden of TB and drug-resistant TB in the country.

Drug resistance and its risk factors among extrapulmonary tuberculosis in Ethiopia: A systematic review and meta-analysis

Background

Drug-resistant tuberculosis and extrapulmonary tuberculosis are the world major public health issues. Although some primary studies have been reported on the burden of drug-resistant tuberculosis in extrapulmonary tuberculosis patients in Ethiopia, there is no systematic review and meta-analysis that attempt to summarize the available literature. Thus, we aimed to estimates the prevalence of drug-resistance in extrapulmonary tuberculosis patients and summarize the risk factors associated with the occurrence of extrapulmonary tuberculosis in Ethiopia.

Methods

We conducted a systematic review of the published primary studies on extrapulmonary drug-resistant tuberculosis in Ethiopia.

Results

Eight observational studies were included in this review from different regions of Ethiopia. The overall pooled prevalence of rifampicin resistance was 6% (95% CI 0.03–0.10), while isoniazid resistance was 7% (95% CI 0.03–0.12). The pooled prevalence of multidrug-resistant tuberculosis was 4% (95% CI 0.01–0.07). Previous tuberculosis treatment history and male gender are frequently reported risk factors for developing drug-resistant tuberculosis in extrapulmonary tuberculosis patients.

Conclusion

The current review has identified a high proportion of resistance to rifampicin, isoniazid, and multidrug-resistant tuberculosis in patients with extrapulmonary tuberculosis in Ethiopia. Clinicians should request drug susceptibility testing for all patients with presumptive extrapulmonary tuberculosis to detect drug-resistance.

Validity of Method for MTBC and NTM Detection in FNAB Specimens from Tuberculous Lymphadenitis Using Microscopy, XPERT MTB / RIF and Culture Method

Mycobacterium tuberculosis and Nontuberculous Mycobacteria usually cause infection in tuberculous lymphadenitis. To improve accuracy of the detection MTB and NTM bacteria it is necessary to select valid methods. This study aims to compare validity of diagnostic methods from FNAB specimens for determining tuberculous lymphadenitis patients. a descriptive observational laboratory study involved 35 samples were obtained from tuberculous lymphadenitis patients in Dr. Soetomo Hospital Surabaya East Java. All specimens examined Ziehl-Neelsen staining microscopy, Xpert MTB/RIF , culture method Middlebrook7H10 solid media and  MGIT as Gold standard. Identification of MTB dan NTM with SD Bioline TB Ag MPT64 and niacin paper strip BD . Used diagnostic test 2x2 to analyze sensitivity, specificity, negative predictive value and positive predictive value. Ziehl-Neelsen staining microscopy Sensitivity 83,33 %  and Specificity 95,65% of  , PPV  90,91%and NPV 91,67%, Diagnostic Accuracy 91,43 % . Xpert MTB/RIF Sensitivity 75% and Specificity 95,65% , PPV  90 % and NPV 88 %, Diagnostic Accuracy 88,57 % with 95% CI (Confidence Interval ) . Characteristics female dominated 23/35 (65.7%) while Male numbered 12/35 (34.3%), age range distribution of TB lymphadenitis patients is highest in young adults 17 years to 25 years as many as 15/35 (42.9%) the second highest is the age group of 36 years to 45 years by 8/35 (22.9%), Clinicial presentation are mostly lymph node enlargement in cervical  37% patients other locations supraclavicular ,mamae. Clinical symptoms mostly lymphadenopathy 31,5% and other lymphadenopathy with fever. Microscopy method still have the good validity shoul be conjunction with the  molecular rapid tests and culture as gold standard in determining the diagnosis of TB lymphadenitis.

Xpert MTB/RIF Ultra and Xpert MTB/RIF assays for extrapulmonary tuberculosis and rifampicin resistance in adults

BACKGROUND

Xpert MTB/RIF Ultra (Xpert Ultra) and Xpert MTB/RIF are World Health Organization (WHO)-recommended rapid nucleic acid amplification tests (NAATs) widely used for simultaneous detection of Mycobacterium tuberculosis complex and rifampicin resistance in sputum. To extend our previous review on extrapulmonary tuberculosis (Kohli 2018), we performed this update to inform updated WHO policy (WHO Consolidated Guidelines (Module 3) 2020).

OBJECTIVES

To estimate diagnostic accuracy of Xpert Ultra and Xpert MTB/RIF for extrapulmonary tuberculosis and rifampicin resistance in adults with presumptive extrapulmonary tuberculosis.

SEARCH METHODS

Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, Web of Science, Latin American Caribbean Health Sciences Literature, Scopus, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, the International Standard Randomized Controlled Trial Number Registry, and ProQuest, 2 August 2019 and 28 January 2020 (Xpert Ultra studies), without language restriction.

SELECTION CRITERIA

Cross-sectional and cohort studies using non-respiratory specimens. Forms of extrapulmonary tuberculosis: tuberculous meningitis and pleural, lymph node, bone or joint, genitourinary, peritoneal, pericardial, disseminated tuberculosis. Reference standards were culture and a study-defined composite reference standard (tuberculosis detection); phenotypic drug susceptibility testing and line probe assays (rifampicin resistance detection).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias and applicability using QUADAS-2. For tuberculosis detection, we performed separate analyses by specimen type and reference standard using the bivariate model to estimate pooled sensitivity and specificity with 95% credible intervals (CrIs). We applied a latent class meta-analysis model to three forms of extrapulmonary tuberculosis. We assessed certainty of evidence using GRADE.

MAIN RESULTS

69 studies: 67 evaluated Xpert MTB/RIF and 11 evaluated Xpert Ultra, of which nine evaluated both tests. Most studies were conducted in China, India, South Africa, and Uganda. Overall, risk of bias was low for patient selection, index test, and flow and timing domains, and low (49%) or unclear (43%) for the reference standard domain. Applicability for the patient selection domain was unclear for most studies because we were unsure of the clinical settings. Cerebrospinal fluid Xpert Ultra (6 studies) Xpert Ultra pooled sensitivity and specificity (95% CrI) against culture were 89.4% (79.1 to 95.6) (89 participants; low-certainty evidence) and 91.2% (83.2 to 95.7) (386 participants; moderate-certainty evidence). Of 1000 people where 100 have tuberculous meningitis, 168 would be Xpert Ultra-positive: of these, 79 (47%) would not have tuberculosis (false-positives) and 832 would be Xpert Ultra-negative: of these, 11 (1%) would have tuberculosis (false-negatives). Xpert MTB/RIF (30 studies) Xpert MTB/RIF pooled sensitivity and specificity against culture were 71.1% (62.8 to 79.1) (571 participants; moderate-certainty evidence) and 96.9% (95.4 to 98.0) (2824 participants; high-certainty evidence). Of 1000 people where 100 have tuberculous meningitis, 99 would be Xpert MTB/RIF-positive: of these, 28 (28%) would not have tuberculosis; and 901 would be Xpert MTB/RIF-negative: of these, 29 (3%) would have tuberculosis. Pleural fluid Xpert Ultra (4 studies) Xpert Ultra pooled sensitivity and specificity against culture were 75.0% (58.0 to 86.4) (158 participants; very low-certainty evidence) and 87.0% (63.1 to 97.9) (240 participants; very low-certainty evidence). Of 1000 people where 100 have pleural tuberculosis, 192 would be Xpert Ultra-positive: of these, 117 (61%) would not have tuberculosis; and 808 would be Xpert Ultra-negative: of these, 25 (3%) would have tuberculosis. Xpert MTB/RIF (25 studies) Xpert MTB/RIF pooled sensitivity and specificity against culture were 49.5% (39.8 to 59.9) (644 participants; low-certainty evidence) and 98.9% (97.6 to 99.7) (2421 participants; high-certainty evidence). Of 1000 people where 100 have pleural tuberculosis, 60 would be Xpert MTB/RIF-positive: of these, 10 (17%) would not have tuberculosis; and 940 would be Xpert MTB/RIF-negative: of these, 50 (5%) would have tuberculosis. Lymph node aspirate Xpert Ultra (1 study) Xpert Ultra sensitivity and specificity (95% confidence interval) against composite reference standard were 70% (51 to 85) (30 participants; very low-certainty evidence) and 100% (92 to 100) (43 participants; low-certainty evidence). Of 1000 people where 100 have lymph node tuberculosis, 70 would be Xpert Ultra-positive and 0 (0%) would not have tuberculosis; 930 would be Xpert Ultra-negative and 30 (3%) would have tuberculosis. Xpert MTB/RIF (4 studies) Xpert MTB/RIF pooled sensitivity and specificity against composite reference standard were 81.6% (61.9 to 93.3) (377 participants; low-certainty evidence) and 96.4% (91.3 to 98.6) (302 participants; low-certainty evidence). Of 1000 people where 100 have lymph node tuberculosis, 118 would be Xpert MTB/RIF-positive and 37 (31%) would not have tuberculosis; 882 would be Xpert MTB/RIF-negative and 19 (2%) would have tuberculosis. In lymph node aspirate, Xpert MTB/RIF pooled specificity against culture was 86.2% (78.0 to 92.3), lower than that against a composite reference standard. Using the latent class model, Xpert MTB/RIF pooled specificity was 99.5% (99.1 to 99.7), similar to that observed with a composite reference standard. Rifampicin resistance Xpert Ultra (4 studies) Xpert Ultra pooled sensitivity and specificity were 100.0% (95.1 to 100.0), (24 participants; low-certainty evidence) and 100.0% (99.0 to 100.0) (105 participants; moderate-certainty evidence). Of 1000 people where 100 have rifampicin resistance, 100 would be Xpert Ultra-positive (resistant): of these, zero (0%) would not have rifampicin resistance; and 900 would be Xpert Ultra-negative (susceptible): of these, zero (0%) would have rifampicin resistance. Xpert MTB/RIF (19 studies) Xpert MTB/RIF pooled sensitivity and specificity were 96.5% (91.9 to 98.8) (148 participants; high-certainty evidence) and 99.1% (98.0 to 99.7) (822 participants; high-certainty evidence). Of 1000 people where 100 have rifampicin resistance, 105 would be Xpert MTB/RIF-positive (resistant): of these, 8 (8%) would not have rifampicin resistance; and 895 would be Xpert MTB/RIF-negative (susceptible): of these, 3 (0.3%) would have rifampicin resistance.

AUTHORS' CONCLUSIONS

Xpert Ultra and Xpert MTB/RIF may be helpful in diagnosing extrapulmonary tuberculosis. Sensitivity varies across different extrapulmonary specimens: while for most specimens specificity is high, the tests rarely yield a positive result for people without tuberculosis. For tuberculous meningitis, Xpert Ultra had higher sensitivity and lower specificity than Xpert MTB/RIF against culture. Xpert Ultra and Xpert MTB/RIF had similar sensitivity and specificity for rifampicin resistance. Future research should acknowledge the concern associated with culture as a reference standard in paucibacillary specimens and consider ways to address this limitation.

Epidemiology and the diagnostic challenge of extra-pulmonary tuberculosis in a teaching hospital in Ethiopia

BACKGROUND

Ethiopia reported a high rate of extra-pulmonary tuberculosis (EPTB) and the cases are increasing since the last three decades. However, diagnostic evidence to initiate TB treatment among EPTB cases is not well known. Therefore, we described the epidemiology and assessed how EPTB is diagnosed in a teaching hospital in Ethiopia.

METHODS

We conducted a retrospective review among all adult EPTB cases diagnosed in Yekatit 12 Hospital Medical College from 2015 to 2019. Using a standardized data abstraction sheet, we collected data from patients' medical records on sociodemographic, sites, and laboratory diagnosis of EPTB cases.

RESULTS

Of the 965 total TB cases, 49.8%(481) had a recorded diagnosis of EPTB during the study period. The mean age of EPTB patients was 32.9 years (SD±13.9) and 50.7% were males. Tubercular lymphadenitis (40.3%), abdominal (23.4%), and pleural TB(13.5%) were the most common sites of EPTB involvement, followed in descending order by the genitourinary, skeletal, central nervous system, abscess, breast, and laryngeal TB. We found a histopathology finding consistent with EPTB in 59.1% of cases, Acid-fast bacilli positive in 1.5%, and the rest diagnosed on radiological grounds. In the majority of cases, more than one diagnostic method was used to diagnose EPTB cases.

CONCLUSIONS

Nearly half of TB patients had a recorded diagnosis of EPTB that comprise heterogeneous anatomical sites. All EPTB patients were started anti-TB therapy without definitive microbiology results. This indicates the diagnostic challenge of EPTB faced in our setting and proves to be significant for TB control in Ethiopia.

Performance of GeneXpert ultra in the diagnosis of Tuberculous Cervical lymphadenitis in formalin fixed paraffin embedded tissues

The diagnosis of Tuberculous Cervical lymphadenitis (TCL) is challenging. The present study aimed to assess the performance of GeneXpert ultra (GXu) in the diagnosis of TCL on Formalin Fixed, Paraffin Embedded Tissues (FFPET). This study included 35 TCL cases confirmed by positive microbiology and/or positive GXu on Fresh Tissues (FT). The diagnostic performance parameters of GXu on FFPET were determined with reference to microbiology (positive Ziehl Neelsen and/or positive culture) and with reference to positive microbiology and/or positive GXu on FT. The GXu on FFPET was positive in 26/35 (74%) cases. With reference to positive ZN and or culture, the sensitivity, specificity, positive predictive value, and negative predictive value of GXu on FFPET were 63%, 100%, 100% and 71% respectively. With reference to positive microbiology and/or positive GXu on FT, these rates were 74%, 100%, 100% and 40% respectively. GXu on FFPET is a reliable tool for the detection of Mycobacterium tuberculosis complex particularly for cases where microbiological investigations have not been performed.

Diagnosis of tuberculosis by nanoparticle-based immuno-PCR assay based on mycobacterial MPT64 and CFP-10 detection

Aim: To improve the diagnostic accuracy of immuno-PCR (I-PCR) in tuberculosis (TB) patients by using functionalized gold nanoparticles (AuNPs) coupled with detection antibodies and oligonucleotides, and magnetic beads (MBs) conjugated with capture antibodies in the liquid phase. Materials & methods: MB-coupled AuNP-based I-PCR (MB-AuNP-I-PCR) assay was designed to detect a cocktail of Mycobacterium tuberculosis MPT64 and CFP-10 proteins in bodily fluids of TB patients. Results: The sensitivities of 89.3 (n = 94) and 78.1% (n = 73) were observed in pulmonary TB and extrapulmonary TB patients, respectively, with specificities of 97.9-98.3%. Notably, the sensitivities attained by MB-AuNP-I-PCR in smear-negative pulmonary TB and extrapulmonary TB patients were significantly higher (p < 0.05-0.001) than Magneto-ELISA and GeneXpert assay. Conclusion: The improved technology, as well as enhanced diagnostic accuracy of MB-AuNP-I-PCR, may lead to development of an attractive diagnostic kit.

Xpert MTB/RIF and Xpert MTB/RIF Ultra assays for active tuberculosis and rifampicin resistance in children

BACKGROUND

Every year, at least one million children become ill with tuberculosis and around 200,000 children die. Xpert MTB/RIF and Xpert Ultra are World Health Organization (WHO)-recommended rapid molecular tests that simultaneously detect tuberculosis and rifampicin resistance in adults and children with signs and symptoms of tuberculosis, at lower health system levels. To inform updated WHO guidelines on molecular assays, we performed a systematic review on the diagnostic accuracy of these tests in children presumed to have active tuberculosis.

OBJECTIVES

Primary objectives • To determine the diagnostic accuracy of Xpert MTB/RIF and Xpert Ultra for (a) pulmonary tuberculosis in children presumed to have tuberculosis; (b) tuberculous meningitis in children presumed to have tuberculosis; (c) lymph node tuberculosis in children presumed to have tuberculosis; and (d) rifampicin resistance in children presumed to have tuberculosis - For tuberculosis detection, index tests were used as the initial test, replacing standard practice (i.e. smear microscopy or culture) - For detection of rifampicin resistance, index tests replaced culture-based drug susceptibility testing as the initial test Secondary objectives • To compare the accuracy of Xpert MTB/RIF and Xpert Ultra for each of the four target conditions • To investigate potential sources of heterogeneity in accuracy estimates - For tuberculosis detection, we considered age, disease severity, smear-test status, HIV status, clinical setting, specimen type, high tuberculosis burden, and high tuberculosis/HIV burden - For detection of rifampicin resistance, we considered multi-drug-resistant tuberculosis burden • To compare multiple Xpert MTB/RIF or Xpert Ultra results (repeated testing) with the initial Xpert MTB/RIF or Xpert Ultra result SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, and the International Standard Randomized Controlled Trials Number (ISRCTN) Registry up to 29 April 2019, without language restrictions.

SELECTION CRITERIA

Randomized trials, cross-sectional trials, and cohort studies evaluating Xpert MTB/RIF or Xpert Ultra in HIV-positive and HIV-negative children younger than 15 years. Reference standards comprised culture or a composite reference standard for tuberculosis and drug susceptibility testing or MTBDRplus (molecular assay for detection of Mycobacterium tuberculosis and drug resistance) for rifampicin resistance. We included studies evaluating sputum, gastric aspirate, stool, nasopharyngeal or bronchial lavage specimens (pulmonary tuberculosis), cerebrospinal fluid (tuberculous meningitis), fine needle aspirates, or surgical biopsy tissue (lymph node tuberculosis).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed study quality using the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2). For each target condition, we used the bivariate model to estimate pooled sensitivity and specificity with 95% confidence intervals (CIs). We stratified all analyses by type of reference standard. We assessed certainty of evidence using the GRADE approach.

MAIN RESULTS

For pulmonary tuberculosis, 299 data sets (68,544 participants) were available for analysis; for tuberculous meningitis, 10 data sets (423 participants) were available; for lymph node tuberculosis, 10 data sets (318 participants) were available; and for rifampicin resistance, 14 data sets (326 participants) were available. Thirty-nine studies (80%) took place in countries with high tuberculosis burden. Risk of bias was low except for the reference standard domain, for which risk of bias was unclear because many studies collected only one specimen for culture. Detection of pulmonary tuberculosis For sputum specimens, Xpert MTB/RIF pooled sensitivity (95% CI) and specificity (95% CI) verified by culture were 64.6% (55.3% to 72.9%) (23 studies, 493 participants; moderate-certainty evidence) and 99.0% (98.1% to 99.5%) (23 studies, 6119 participants; moderate-certainty evidence). For other specimen types (nasopharyngeal aspirate, 4 studies; gastric aspirate, 14 studies; stool, 11 studies), Xpert MTB/RIF pooled sensitivity ranged between 45.7% and 73.0%, and pooled specificity ranged between 98.1% and 99.6%. For sputum specimens, Xpert Ultra pooled sensitivity (95% CI) and specificity (95% CI) verified by culture were 72.8% (64.7% to 79.6%) (3 studies, 136 participants; low-certainty evidence) and 97.5% (95.8% to 98.5%) (3 studies, 551 participants; high-certainty evidence). For nasopharyngeal specimens, Xpert Ultra sensitivity (95% CI) and specificity (95% CI) were 45.7% (28.9% to 63.3%) and 97.5% (93.7% to 99.3%) (1 study, 195 participants). For all specimen types, Xpert MTB/RIF and Xpert Ultra sensitivity were lower against a composite reference standard than against culture. Detection of tuberculous meningitis For cerebrospinal fluid, Xpert MTB/RIF pooled sensitivity and specificity, verified by culture, were 54.0% (95% CI 27.8% to 78.2%) (6 studies, 28 participants; very low-certainty evidence) and 93.8% (95% CI 84.5% to 97.6%) (6 studies, 213 participants; low-certainty evidence). Detection of lymph node tuberculosis For lymph node aspirates or biopsies, Xpert MTB/RIF pooled sensitivity and specificity, verified by culture, were 90.4% (95% CI 55.7% to 98.6%) (6 studies, 68 participants; very low-certainty evidence) and 89.8% (95% CI 71.5% to 96.8%) (6 studies, 142 participants; low-certainty evidence). Detection of rifampicin resistance Xpert MTB/RIF pooled sensitivity and specificity were 90.0% (67.6% to 97.5%) (6 studies, 20 participants; low-certainty evidence) and 98.3% (87.7% to 99.8%) (6 studies, 203 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

We found Xpert MTB/RIF sensitivity to vary by specimen type, with gastric aspirate specimens having the highest sensitivity followed by sputum and stool, and nasopharyngeal specimens the lowest; specificity in all specimens was > 98%. Compared with Xpert MTB/RIF, Xpert Ultra sensitivity in sputum was higher and specificity slightly lower. Xpert MTB/RIF was accurate for detection of rifampicin resistance. Xpert MTB/RIF was sensitive for diagnosing lymph node tuberculosis. For children with presumed tuberculous meningitis, treatment decisions should be based on the entirety of clinical information and treatment should not be withheld based solely on an Xpert MTB/RIF result. The small numbers of studies and participants, particularly for Xpert Ultra, limits our confidence in the precision of these estimates.

Evaluation of Xpert MTB/RIF for the Diagnosis of Lymphatic Tuberculosis

Background

The World Health Organization approved the use of Xpert MTB/RIF for the detection of Mycobacterium tuberculosis DNA, which has significantly improved the diagnosis of tuberculosis. In this study, our main objective was to evaluate the diagnostic efficacy of Xpert MTB/RIF for lymphoid tuberculosis to determine whether Xpert MTB/RIF could be used as a routine detection method.

Materials and Methods

We searched four databases for the relevant literature published from May 2007 to December 2019. The quality of the literature was evaluated with reference to the evaluation criteria. Data that were extracted from the literature on Xpert MTB/RIF diagnosis of lymphatic tuberculosis were used to plot the summary receiver operating characteristic (SROC) curve, after which the software was used to combine and analyze the accuracy of these data.

Results

A total of 27 studies were included. The sensitivity of Xpert MTB/RIF for detecting lymphatic tuberculosis was 0.79 (95% CI (0.77, 0.81)), the specificity was 0.88 (95% CI (0.87, 0.90)), and the positive likelihood ratio (PLR) was 7.21 (95% CI (4.93, 10.55)). In addition, the negative likelihood ratio (NLR) was 0.25 (95% CI (0.19, 0.32)) and the diagnostic odds ratio (DOR) was 40.23 (95% CI (24.53, 65.98)). At the same time, we used the extracted data to make the SROC curve, obtaining the following parameters: area under the curve (AUC) = 0.9144, Q = 0.8470 (SE = 0.0163).

Conclusion

Xpert MTB/RIF has high accuracy in detecting lymphatic tuberculosis, and it can be used to quickly and easily diagnose lymphatic tuberculosis at an early stage as a general method.

Does Xpert® MTB/RIF assay give rifampicin resistance results without identified mutation? Review of cases from Addis Ababa, Ethiopia

BACKGROUND

Xpert® MTB/RIF assay is currently used in Ethiopia for the rapid diagnosis of Mycobacterium tuberculosis (MTB) and mutations that confer Rifampicin resistance. Rifampicin resistance is determined based on any mutation in the 81 bp of rpoB gene using five overlapping probes represented as Probe A (codons 507-511), Probe B (codons 512-518), Probe C (codons 518-523), Probe D (codons 523-529) and Probe E (codons 529-533). In this review, we assessed the frequency of missed probe types for Rifampicin Resistance results.

METHODS

Data were reviewed from specimens received and tested using Xpert® MTB/RIF assay at Ethiopian National Tuberculosis Reference Laboratory, in Addis Ababa from 15 July 2016 to 31 December 2018 retrospectively. All archived data were reviewed carefully to describe missed probe types and the quantity of DNA in the sample.

RESULTS

A total of 100 specimens were reported as MTB Detected Rifampicin Resistance Detected by Xpert® MTB/RIF assay. More than half (55%) of these results were reported from male patients. The median age was 28.0 years (5 months to 88 years). Majorities (62%) of the cases were detected from sputum. Among the total of 38 extrapulmonary samples, lymph node aspirates were accounted for 50% (19/38). The most common mutations (81.0%) were found in the Probe E region followed by Probe D (10.0%), and Probe B (3.0%). Mutations in Probe A and Probe C regions were not observed. However, six (6.0%) Rifampicin resistance cases were found without any missed probe type. The delta Ct max is ≥4.3. No specimen yielded Rifampicin resistance associated with more than one probe failure or mutation combinations.

CONCLUSION

Mutations associated with Probe E (codons 529-533) region were identified as the commonest rpoB gene mutations. The Rifampicin resistance results found without any identified missing probe needs further study. The lower DNA amount was observed in extrapulmonary specimens compared with sputum.

EBUS-TBNA in the rapid microbiological diagnosis of drug-resistant mediastinal tuberculous lymphadenopathy

This study aimed to examine the use of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the rapid diagnosis of mediastinal tuberculous lymphadenitis and drug-resistant mediastinal tuberculous lymphadenitis. A diagnosis of TB was confirmed by a positive Xpert MTB/RIF test or Mycobacterium tuberculosis culture. Rifampicin-resistant TB (RR-TB) or multidrug-resistant TB (MDR-TB) was diagnosed upon the detection of rifampicin resistance by Xpert MTB/RIF or resistance to rifampicin and isoniazid by phenotypic drug susceptibility testing (DST). Xpert MTB/RIF was positive in 43 of 56 patients (77%) and TB culture was positive in 31 of 56 patients (55%). Of these 56 patients, 25 (45%) were Xpert MTB/RIF positive and TB culture negative, 13 (23%) were Xpert MTB/RIF negative and TB culture positive, and 18 (32%) were Xpert MTB/RIF positive and TB culture positive. 11 patients (20%) had drug-resistant TB: seven with RR/MDR-TB, one with pre-extensively drug-resistant (XDR) TB, two with XDR-TB and one with isoniazid mono-resistance. An Xpert MTB/RIF assay carried out on EBUS-TBNA specimens provides rapid diagnosis of TB. Xpert MTB/RIF testing appears to have additional and more rapid sensitivity compared with culture alone. Culture-based DST provides an additional exclusive yield and the full resistance profile in addition to or instead of rifampicin resistance.

Comparative evaluation of loop-mediated isothermal amplification (LAMP) assay, GeneXpert MTB/Rif and multiplex PCR for the diagnosis of tubercular lymphadenitis in HIV-infected patients of North India

BACKGROUND

Tubercular lymphadenitis (TBLA) is one of the most common extrapulmonary manifestations of tuberculosis in patients with HIV. With several other pathological conditions presenting as lymphadenitis and lack of consensus regarding a gold standard test, the diagnosis of TBLA remains a challenge for the clinician.

OBJECTIVES

and design: In this study, we have assessed the potential of loop-mediated isothermal amplification (LAMP) test for the diagnosis of TBLA in HIV-infected patients. The study group included samples collected by fine needle aspiration (FNAC) of lymph nodes from 24 HIV-infected patients with TBLA. A composite reference standard was used to identify cases of TBLA based on clinical suspicion, results of cytology, AFB smear, MGIT culture, GeneXpert MTB/RIF, multiplex polymerase chain reaction (MPCR) and subsequently clinical response to antitubercular therapy. These tests were also carried out in 26 control samples of lymph node FNAC from HIV-infected patients with non-tubercular lymphadenitis.

RESULTS

LAMP assay was positive in 19/24 TBLA cases and yielded a sensitivity of 79.17% with 100% specificity. Cytology was suggestive in 18/24 (75%) TBLA cases. GeneXpert MTB/RIF assay correctly identified 16/24 TBLA cases, but the test did show one false positive result reducing its specificity. MPCR had the highest sensitivity of 91.67% as it correctly identified 22/24 cases and showed no false positive result.

CONCLUSION

The current study highlights the potential of LAMP test for the specific diagnosis of tubercular lymphadenitis in FNAC samples from HIV-infected patients, especially when cytology is either non-conclusive or non-available. Though MPCR had a higher sensitivity than LAMP assay, the added advantages of low cost, minimal technical expertise and simplicity of procedure make LAMP assay a suitable diagnostic test in resource-limited settings.

Diagnostic accuracy of Xpert MTB/RIF assay and non-molecular methods for the diagnosis of tuberculosis lymphadenitis

Background

Tuberculous lymphadenitis (TBLN) diagnosis remains a challenge in resource limited countries like Ethiopia. Most diagnostic centers in Ethiopia use smear microscopy, but it has low sensitivity in detecting tubercle bacilli in fine needle aspiration (FNA) specimens. FNA cytology (FNAC) is another widely applicable diagnostic option but it has low specificity for diagnosing TBLN. In 2014, WHO recommended Xpert MTB/RIF assay to be used in detecting TB from FNA specimen by considering the diagnostic limitations of microscopy and cytology. In Ethiopia, there is limited data on Xpert MTB/RIF performance in detecting TBLN from FNA. Therefore, this study aimed to evaluate the diagnostic performance of Xpert MTB/RIF assay and non-molecular methods (cytology, microscopy and culture) for the diagnosis of TBLN.

Methods

A cross-sectional study was conducted on 152 presumptive TBLN patients at St. Paul’s Hospital Millennium Medical College (SPHMMC) from December 2015 to May 2016 in Addis Ababa, Ethiopia. FNA specimens were collected from each patient. Individual patient specimens were examined by microscopy (acid fast and auramine O staining), cytology, Xpert MTB/RIF and culture. Each specimen was directly inoculated and its sediment following decontamination procedure onto two duplicate Löwenstein-Jensen (LJ) media. Composite culture (specimen positive by direct or concentrated or both culturing methods) and composite method (positive by either one of the non-molecular methods) were taken as reference methods. The data was captured and analyzed using software packages SPSS version 20 (SPSS Inc, Chicago, Illinois, USA). Sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

Result

A total of 152 presumptive TBLN patients were enrolled in this study. Of these, 105(69%), 68(44.7%), 64(42%), 48(32%) and 33(22%) were positive for M. tuberculosis using composite method (positive by either one of the non-molecular method), composite culture, direct, and concentrated culture, respectively. TB positivity rate was 67.8%, 49.3%, 24.3%, and 14.5% using cytology, Xpert MTB/RIF, Auramine O (FM) microscopy, and Ziehl Nelson (ZN) microscopy, respectively. Using composite culture as reference, the sensitivity and specificity of Xpert MTB/RIF was 78% (95% CI: 73.7% to 82.3%) and 74% (95%CI: 69.4% to 78.6%), respectively. However, the sensitivity of Xpert MTB/RF improved from 78% to 92% using composite method as a reference. The high positivity rate observed in purulent (70%) followed by caseous (66.7%) type of aspirates by Xpert MTB/RIF.

Conclusion

Xpert MTB/RIF assay has both considerable sensitivity and specificity; it may be employed for better diagnosis, management and treatment of presumptive TBLN patients.

Needle Biopsy Adequacy in the Era of Precision Medicine and Value-Based Health Care

CONTEXT.—

Needle biopsy of diseased tissue is an essential diagnostic tool that is becoming even more important as precision medicine develops. However, the capability of this modality to efficiently provide samples adequate for diagnostic and prognostic analysis remains quite limited relative to current diagnostic needs. For physicians and patients, inadequate biopsy frequently leads to diagnostic delay, procedure duplication, or insufficient information about tumor biology leading to delay in treatment; for health systems, this results in substantial incremental costs and inefficient use of scarce specialized diagnostic resources.

OBJECTIVE.—

To review current needle biopsy technology, devices, and practice with a perspective to identify current limitations and opportunities for improvement in the context of advancing precision medicine.

DATA SOURCES.—

PubMed searches of fine-needle aspiration and core needle biopsy devices and similar technologies were made generally, by tissue site, and by adequacy as well as by health economics of these technologies.

CONCLUSIONS.—

Needle biopsy adequacy can be improved by recognizing the importance of this diagnostic tool by promoting common criteria for needle biopsy adequacy; by optimizing needle biopsy procedural technique, technologies, clinical practice, professional education, and quality assurance; and by bundling biopsy procedure costs with downstream diagnostic modalities to provide better accountability and incentives to improve the diagnostic process.

Diagnostic Accuracy of the Xpert MTB/RIF Assay for Lymph Node Tuberculosis: A Systematic Review and Meta-Analysis

Objectives

To evaluate the performance of Xpert MTB/RIF for lymph node tuberculosis (LNTB).

Methods

We searched databases for published reports. We reviewed the studies and identified the performance of Xpert MTB/RIF with respect to a composite reference standard (CRS) and culture. We used a bivariate random-effects model to perform meta-analyses and used metaregression to analyze sources of heterogeneity.

Results

15 independent studies compared Xpert MTB/RIF with CRS while 21 comparing it with culture were included. The pooled sensitivity and specificity of Xpert MTB/RIF were 79% and 98% compared to that of CRS, respectively, and 84% and 91% compared to that of culture, respectively. The pooled sensitivity and specificity using fine needle aspiration (FNA) samples versus CRS were 80% and 96%, whereas those against culture were 90% and 89%, respectively. The percentages while working with tissue samples versus CRS were 76% and 100%, respectively, whereas those against culture were 76% and 92%, respectively. There was no significant difference in diagnostic efficiency among the types of specimen.

Conclusions

Xpert MTB/RIF demonstrates good diagnostic efficiency for LNTB and is not related to the type of specimen, obtained via different routes.

Diagnostic accuracy of Xpert MTB/RIF assay in extrapulmonary tuberculosis

Introduction

The WHO endorsed Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay, has been evaluated for pulmonary TB in a number of studies but very few have investigated it for extrapulmonary specimens. The present study evaluates the performance of Xpert MTB/RIF assay in the diagnosis of extrapulmonary TB (EPTB).

Aim and Objectives

The aim of the study is to determine sensitivity and specificity of Xpert MTB/RIF assay for diagnosis of EPTB and RIF resistance in comparison to culture on Lowenstein-Jensen (LJ) medium and proportion method (PM), respectively.

Materials and Methods

A total of 738 specimens from clinically suspected cases of EPTB were subjected to Ziehl-Neelsen staining, Xpert MTB/RIF assay and culture on LJ medium. PM was done on MTB isolates.

Results

The sensitivity, specificity of Xpert MTB/RIF assay for diagnosis of EPTB were 84.91% (95% confidence interval [CI] 72.41%-93.25%) and 86.72% (95% CI 83.94%-89.17%) and for RIF resistance detection were 60.00% (95% CI 32.29%-83.66%) and 94.74% (95% CI 73.97%-99.87%), respectively. Among culture-positive cases, the sensitivity of Xpert MTB/RIF assay was 94.12% in smear positive and 80.56% in smear-negative cases. Xpert MTB/RIF showed maximum sensitivity of MTB detection from lymph node specimens (100% [95% CI 54.07%-100.00%]) and other body fluids (100% [95% CI 15.81%-100.00%]).

Conclusion

The present study establishes Xpert MTB/RIF assay as a promising tool in the rapid diagnosis of EPTB and detection of RIF resistance.

Lymph nodes are sites of prolonged bacterial persistence during Mycobacterium tuberculosis infection in macaques

Tuberculosis is commonly considered a chronic lung disease, however, extrapulmonary infection can occur in any organ. Even though lymph nodes (LN) are among the most common sites of extrapulmonary Mycobacterium tuberculosis (Mtb) infection, and thoracic LNs are frequently infected in humans, bacterial dynamics and the effect of Mtb infection in LN structure and function is relatively unstudied. We surveyed thoracic LNs from Mtb-infected cynomolgus and rhesus macaques analyzing PET CT scans, bacterial burden, LN structure and immune function. FDG avidity correlated with the presence of live bacteria in LNs at necropsy. Lymph nodes have different trajectories (increasing, maintaining, decreasing in PET activity over time) even within the same animal. Rhesus macaques are more susceptible to Mtb infection than cynomolgus macaques and this is in part due to more extensive LN pathology. Here, we show that Mtb grows to the same level in cynomolgus and rhesus macaque LNs, however, cynomolgus macaques control Mtb at later time points post-infection while rhesus macaques do not. Notably, compared to lung granulomas, LNs are generally poor at killing Mtb, even with drug treatment. Granulomas that form in LNs lack B cell-rich tertiary lymphoid structures, disrupt LN structure by pushing out T cells and B cells, introduce large numbers of macrophages that can serve as niches for Mtb, and destroy normal vasculature. Our data support that LNs are not only sites of antigen presentation and immune activation during infection, but also serve as important sites for persistence of significant numbers of Mtb bacilli.

Since tuberculosis is commonly considered a chronic lung disease, most studies in tuberculosis focus on the lungs while lymph nodes are almost always depicted only as sites of antigen presentation and immune activation. However, lymph nodes are among the most frequently infected sites of Mycobacterium tuberculosis (Mtb) aside from the lungs. The effect of Mtb infection and how lymph nodes respond to Mtb infection is currently unknown. To investigate this, we examined the lymph nodes of two macaque species, cynomolgus and rhesus macaques, at different time points after Mtb infection. We found that overall lymph nodes are not effective killers of Mtb; the lymph nodes of rhesus macaques being less effective at killing Mtb than cynomolgus macaques. Mtb infection also resulted in the destruction of the lymph node structure and this was associated with increased bacterial burden. After a short course of anti-TB drug therapy, the reduction in bacterial burden was lower in lymph nodes compared to lung granulomas. Our data show that aside from being sites of antigen presentation and immune activation, lymph nodes are also niches of Mtb growth and persistence.

Xpert® MTB/RIF assay for extrapulmonary tuberculosis and rifampicin resistance

BACKGROUND

Tuberculosis (TB) is the world's leading infectious cause of death. Extrapulmonary TB accounts for 15% of TB cases, but the proportion is increasing, and over half a million people were newly diagnosed with rifampicin-resistant TB in 2016. Xpert^® MTB/RIF (Xpert) is a World Health Organization (WHO)-recommended, rapid, automated, nucleic acid amplification assay that is used widely for simultaneous detection of Mycobacterium tuberculosis complex and rifampicin resistance in sputum specimens. This Cochrane Review assessed the accuracy of Xpert in extrapulmonary specimens.

OBJECTIVES

To determine the diagnostic accuracy of Xpert a) for extrapulmonary TB by site of disease in people presumed to have extrapulmonary TB; and b) for rifampicin resistance in people presumed to have extrapulmonary TB.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, Web of Science, Latin American Caribbean Health Sciences Literature (LILACS), Scopus, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, the International Standard Randomized Controlled Trial Number (ISRCTN) Registry, and ProQuest up to 7 August 2017 without language restriction.

SELECTION CRITERIA

We included diagnostic accuracy studies of Xpert in people presumed to have extrapulmonary TB. We included TB meningitis and pleural, lymph node, bone or joint, genitourinary, peritoneal, pericardial, and disseminated TB. We used culture as the reference standard. For pleural TB, we also included a composite reference standard, which defined a positive result as the presence of granulomatous inflammation or a positive culture result. For rifampicin resistance, we used culture-based drug susceptibility testing or MTBDRplus as the reference standard.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed risk of bias and applicability using the QUADAS-2 tool. We determined pooled predicted sensitivity and specificity for TB, grouped by type of extrapulmonary specimen, and for rifampicin resistance. For TB detection, we used a bivariate random-effects model. Recognizing that use of culture may lead to misclassification of cases of extrapulmonary TB as 'not TB' owing to the paucibacillary nature of the disease, we adjusted accuracy estimates by applying a latent class meta-analysis model. For rifampicin resistance detection, we performed univariate meta-analyses for sensitivity and specificity separately to include studies in which no rifampicin resistance was detected. We used theoretical populations with an assumed prevalence to provide illustrative numbers of patients with false positive and false negative results.

MAIN RESULTS

We included 66 unique studies that evaluated 16,213 specimens for detection of extrapulmonary TB and rifampicin resistance. We identified only one study that evaluated the newest test version, Xpert MTB/RIF Ultra (Ultra), for TB meningitis. Fifty studies (76%) took place in low- or middle-income countries. Risk of bias was low for patient selection, index test, and flow and timing domains and was high or unclear for the reference standard domain (most of these studies decontaminated sterile specimens before culture inoculation). Regarding applicability, in the patient selection domain, we scored high or unclear concern for most studies because either patients were evaluated exclusively as inpatients at tertiary care centres, or we were not sure about the clinical settings.Pooled Xpert sensitivity (defined by culture) varied across different types of specimens (31% in pleural tissue to 97% in bone or joint fluid); Xpert sensitivity was > 80% in urine and bone or joint fluid and tissue. Pooled Xpert specificity (defined by culture) varied less than sensitivity (82% in bone or joint tissue to 99% in pleural fluid and urine). Xpert specificity was ≥ 98% in cerebrospinal fluid, pleural fluid, urine, and peritoneal fluid.Xpert testing in cerebrospinal fluidXpert pooled sensitivity and specificity (95% credible interval (CrI)) against culture were 71.1% (60.9% to 80.4%) and 98.0% (97.0% to 98.8%), respectively (29 studies, 3774 specimens; moderate-certainty evidence).For a population of 1000 people where 100 have TB meningitis on culture, 89 would be Xpert-positive: of these, 18 (20%) would not have TB (false-positives); and 911 would be Xpert-negative: of these, 29 (3%) would have TB (false-negatives).For TB meningitis, ultra sensitivity and specificity against culture (95% confidence interval (CI)) were 90% (55% to 100%) and 90% (83% to 95%), respectively (one study, 129 participants).Xpert testing in pleural fluidXpert pooled sensitivity and specificity (95% CrI) against culture were 50.9% (39.7% to 62.8%) and 99.2% (98.2% to 99.7%), respectively (27 studies, 4006 specimens; low-certainty evidence).For a population of 1000 people where 150 have pleural TB on culture, 83 would be Xpert-positive: of these, seven (8%) would not have TB (false-positives); and 917 would be Xpert-negative: of these, 74 (8%) would have TB (false-negatives).Xpert testing in urineXpert pooled sensitivity and specificity (95% CrI) against culture were 82.7% (69.6% to 91.1%) and 98.7% (94.8% to 99.7%), respectively (13 studies, 1199 specimens; moderate-certainty evidence).For a population of 1000 people where 70 have genitourinary TB on culture, 70 would be Xpert-positive: of these, 12 (17%) would not have TB (false-positives); and 930 would be Xpert-negative: of these, 12 (1%) would have TB (false-negatives).Xpert testing for rifampicin resistanceXpert pooled sensitivity (20 studies, 148 specimens) and specificity (39 studies, 1088 specimens) were 95.0% (89.7% to 97.9%) and 98.7% (97.8% to 99.4%), respectively (high-certainty evidence).For a population of 1000 people where 120 have rifampicin-resistant TB, 125 would be positive for rifampicin-resistant TB: of these, 11 (9%) would not have rifampicin resistance (false-positives); and 875 would be negative for rifampicin-resistant TB: of these, 6 (1%) would have rifampicin resistance (false-negatives).For lymph node TB, the accuracy of culture, the reference standard used, presented a greater concern for bias than in other forms of extrapulmonary TB.

AUTHORS' CONCLUSIONS

In people presumed to have extrapulmonary TB, Xpert may be helpful in confirming the diagnosis. Xpert sensitivity varies across different extrapulmonary specimens, while for most specimens, specificity is high, the test rarely yielding a positive result for people without TB (defined by culture). Xpert is accurate for detection of rifampicin resistance. For people with presumed TB meningitis, treatment should be based on clinical judgement, and not withheld solely on an Xpert result, as is common practice when culture results are negative.

Empirical treatment with non-anti-tuberculosis antibiotics decreased microbiological detection in cervical tuberculous lymphadenitis

Diagnosis of cervical tuberculous lymphadenitis (CTL), the most commonly occurring form of extrapulmonary tuberculosis, remains as a challenge in clinic. Detection of the presence of Mycobacterium tuberculosis (Mtb) in fine needle aspiration cytology (FNAC) samples is one golden criterion to confirm the CTL diagnosis. Due to the non-specific clinical presentation, CTL might be confused with other lymph node enlargement diseases; therefore empirical treatment with non-anti-TB antibiotics is often initially administered. However, it is still unclear whether this diagnostic antibiotic treatment affects the positivity of Mtb detection in FNAC. The demographics and clinical characteristics of 732 lymph node enlargement patients who had underwent FNAC were retrospectively analyzed and 605 (82.65%) of them were diagnosed as CTL. A total of 279 CTL cases (279/605, 46.11%) with completion of three Mtb tests (AFB, NAAT, and Mtb culture) in FNAC samples were selected for analyzing the effect of empirical antibiotic treatment on the positivity of Mtb tests. Compared to CTL patients without antibiotic treatment prior to FNAC, patients received empirical non anti-TB treatment had significantly lower positivity for acid fast bacilli staining (adjusted OR 0.11, 95% CI 0.06-0.21), nucleic acid amplification test (NAAT) (adjusted OR 0.38, 95% CI 0.21-0.71), and Mtb culture (adjusted OR 0.11, 95% CI 0.06-0.19). In conclusion, this study demonstrated that empirical non anti-TB antibiotic treatment reduced the opportunity to confirm CTL by microbiological analysis. Patients with cervical lymph node enlargement should undergo FNAC for Mtb tests prior to initiation of empirical non anti-TB treatment.

Xpert MTB/RIF assay for the diagnosis of Mycobacterium tuberculosis and Rifampicin resistance in high Human Immunodeficiency Virus setting in Gambella regional state, southwest Ethiopia

Background

The introduction of a new and rapid molecular diagnostic for tuberculosis (TB) and rifampicin resistance (RIF) in the national TB program has improved the diagnosis of TB by shortening the turnaround time and detecting the presence of RIF resistance in high TB and human immunodeficiency virus (HIV) settings such as Ethiopia. However, the implementation of this new diagnostic tool for the diagnosis of M. tuberculosis (MTB) and rifampicin (RIF) resistance in clinical setting is limited known in the country. Hence, this study intended to describe the program of GeneXpert MTB/RIF in the diagnosis of TB and RIF in high HIV setting in Gambella Regional State, Southwest Ethiopia.

Method

Institutional based retrospective study was conducted among presumptive TB patients diagnosed with GeneXpert assay in the last three years (2015–2017) in Gambella Hospital from May 1–30, 2017. The data were collected from GeneXpert registration book using standard data extraction sheet. The data were entered and cleared using EPI data 3.1 and then, exported and analyzed using SPSS version 20.0 statistical software package.

Result

Of the 995 presumptive TB patients who received the GeneXpert test in the last three years, 20.0% (95% CI: 17.4–22.7) of them had proven MTB detection while 4.9% (95% CI: 2.2–8.1) had RIF resistance. The prevalence of RIF resistance was 2.3% and 14.3% among the new and retreated cases respectively. There was also a 35.5% TB/HIV co-infections. The odd of MTB detection was higher among 15–29 [AOR 2.17 (95% CI: 1.25- 3.76)] and 30–44 [AOR 2.35 (95% CI: 1.36–4.07)] year old participants. The figure was however significantly lower among female [AOR 0.64 (95% CI: 0.45–0.91)] and unknown HIV status [AOR 0.38(95% CI: 0.24–0.61)] participants of the study. In addition, the odd of RIF resistance was significantly low among HIV unknown case [AOR 0.14 (95% CI: 0.02–0.96)]. It was also learnt that there was progressively decline of invalid or error Xpert result from 4.7% to 2.0% in the course of the study period (X², 25.54; P = 0.001).

Conclusion

The study confirms the high prevalence of TB, RIF resistance and TB/HIV co-infection among the study participants. Age, sex, and HIV status of the study participants were predictor factors for MTB detection while HIV status was associated with RIF resistance. Therefore, the results of the study indicate that there is the need for collaborative and intensified prevention of TB and HIV in the study area. The ongoing supervision and mentoring to improve the performance of Xpert in the institution need to be promoted.

Lung Infections

A review of pulmonary infections of all types with diagnostic and morphological features.

Rapid detection of Mycobacterium tuberculosis and rifampicin resistance in extrapulmonary tuberculosis and sputum smear-negative pulmonary suspects using Xpert MTB/RIF

BACKGROUND

Tuberculosis (TB) is a serious public health problem in developing countries such as Pakistan. Rapid diagnosis of TB and detection of drug resistance are very important for timely and appropriate management of multidrug-resistant TB (MDR-TB).

OBJECTIVE

The purpose of this study was to determine the diagnostic efficacy of the Xpert MTB/RIF assay for rapid diagnosis of TB and detection of rifampicin (RIF) resistance in extrapulmonary and smear-negative pulmonary TB suspects.

METHODS

A total of 98 bronchoalveolar lavage fluid (BALF) and 168 extrapulmonary specimens were processed by Xpert MTB/RIF. Culture results are considered as the gold standard for diagnosis of TB, and drug susceptibility testing for detection of RIF resistance. Diagnostic efficacy was measured in terms of sensitivity, specificity and positive and negative predictive values.

RESULTS

The Xpert MTB/RIF assay detected 40 (40.8 %) of 98 BALF of presumptive pulmonary TB and 60 (35.7 %) of 168 extrapulmonary specimens. Sensitivity and specificity of the Xpert MTB/RIF assay for detection of TB was 86 and 88.4 %, respectively. The positive predictive value was 71.5 % while negative predictive value was 95.1 %.

CONCLUSION

The Xpert MTB/RIF assay is a rapid and simple technique with high sensitivity and specificity for diagnosing TB and detecting drug resistance in extrapulmonary and smear-negative TB cases.

Mycobacterium tuberculosis Complex and HIV Co-Infection among Extrapulmonary Tuberculosis Suspected Cases at the University of Gondar Hospital, Northwestern Ethiopia

Background

Extrapulmonary Tuberculosis (EPTB) and Human Immunodeficiency Virus (HIV) infection are interrelated as a result of immune depression. The aim of this study was to determine the prevalence of Mycobacterium tuberculosis complex isolates and the burden of HIV co-infection among EPTB suspected patients.

Method

An institution based cross-sectional study was conducted among EPTB suspected patients at the University of Gondar Hospital. Socio-demographic characteristics and other clinical data were collected using a pretested questionnaire. GeneXpert MTB/RIF assay was performed to diagnosis Mycobacterium tuberculosis complex and Rifampicin resistance. All samples were also investigated by cytology and culture. The HIV statuses of all patients were screened initially by KHB, and all positive cases were further re-tested by STAT-pack. Data was analyzed using SPSS version 20 computer software and a P-value of < 0.05 was taken as statistically significant.

Results

A total of 141 extrapulmonary suspected patients were enrolled in this study. The overall prevalence of culture confirmed extrapulmonary tuberculosis infection was 29.8%, but the GeneXpert result showed a 26.2% prevalence of Mycobacterium tuberculosis complex infection. The 78.4% prevalence of extrapulmonary tuberculosis infection was found to be higher among the adult population. The prevalence of HIV infection among EPTB suspected patients was 14.1%, while it was 32.4% among GeneXpert-confirmed extrapulmonary TB cases (12/37). Tuberculosis lymphadenitis was the predominant (78.4%) type of EPTB infection followed by tuberculosis cold abscess (10.7%). Adult hood, previous history of contact with known pulmonary tuberculosis patients, and HIV co-infection showed a statistically significant association with extrapulmonary tuberculosis infection (P<0.013).

Conclusion

The prevalence of culture confirmed-EPTB infection was high, and a higher EPTB-HIV co-infection was also observed.