Identification of the causative organism of tuberculous lymphadenitis in ethiopia by PCR

Comparative Diagnostic of Cervical Tuberculous Lymphadenitis: PCR is a Fast, Efficient, and Improved Diagnostic Approach

Methods

The study included 100 clinically suspected cases of TBLN. Fine needle aspirate (FNA) samples were processed for cytology staining and cultured on LJ & BACTEC 12B media. The biochemical tests were performed to identify the isolates at the species level. Additionally, for PCR, DNA was extracted and used for the diagnosis and identification of mycobacterial species.

Results

Patients ranged from 2 to 45 years with a mean age of 24.96 ± 9.10 years. Out of 100 patients, 73% had clinical symptoms of weight loss, followed by fever (72%), anorexia (66%), and night sweats (58%). 24% of patients were found to be smear-positive after Ziehl-Neelsen (ZN) staining and statistically highly significant with PCR. On LJ medium 34% and on BACTEC radiometric 45% of samples were smearing positive. Overall, 48% of cases were PCR-positive for TBLN. When compared with culture, the sensitivity and specificity of PCR were 93.75% and 100%, respectively, which are higher than cytology. The true positive predictive value (PPV) and negative predictive value (NPV) were 83.3% and 61.5%, respectively.

Conclusion

This study suggests that PCR is a rapid, sensitive, and specific tool for correct diagnosis of TBLN cases as compared to staining and culture which lead to the early and proper management of mycobacterial diseases.

Genetic diversity and drug resistance profiles of Mycobacterium tuberculosis complex isolates from patients with extrapulmonary tuberculosis in Ghana and their associated host immune responses

•

Pleural TB and TB lymphadenitis are the most common forms of extrapulmonary TB in Ghana.

•

M. tb sub-lineage Cameroon is associated with decreased serum IL-1β, IL-17A, and IFN-α.

•

A significant association was observed between age and M. tb complex lineages.

•

Generally, M. bovis contributes minimally to human extrapulmonary TB in Ghana.

Objectives

This study sought to determine the genetic diversity and drug resistance profiles of Mycobacterium tuberculosis complex (MTBC) isolates from extrapulmonary tuberculosis (EPTB) patients in Ghana, and their associated immune responses.

Methods

Spoligotyping was performed on 102 MTBC isolates from EPTB patients. Lineages/sub-lineages were assigned by comparing spoligotyping patterns primarily with the SITVIT2 database and subsequently with the TB-Lineage online tool for unknown isolates in SITVIT2. Drug susceptibility testing was performed using MGIT (BD BACTEC 960), Lowenstein-Jensen media (indirect proportion method), and GenoType MTBDRplus/MTBDRsl assays. Differential cytokine levels in the serum of 20 EPTB patients infected with MTBC lineage 4 were determined using the Luminex multiplex immunoassay.

Results

Around 95% (97/102) of isolates were Mycobacterium tuberculosis, predominantly lineage 4 (95%; 92/97). Of the lineage 4 isolates, the majority were sub-lineage Cameroon (37%, 34/92). Prevalence was significantly higher in the 15–34 years age group among EPTB patients infected with lineage 4 strains (p = 0.024). Fifteen isolates were resistant to at least one anti-TB drug tested. Decreased levels of IL-1β, IL-17A, and IFN-α were observed in individuals infected with Cameroon sub-lineages compared with other lineage 4 sub-lineages.

Conclusions

Our study confirms Cameroon (SIT61) as the most common spoligotype causing human EPTB in Ghana, and that it is associated with decreased serum IL-1β, IL-17A, and IFN-α.

Public Awareness, Prevalence and Potential Determinants of Bovine Tuberculosis in Selected Districts of Gamo Zone, Southern Ethiopia

Purpose

Bovine tuberculosis (bTB) is infectious chronic disease of animals mainly caused by bacillus Mycobacterium bovis. It is known endemic disease of cattle in Ethiopia. In the current study sites, there is little information on bovine tuberculosis. Thus, this study was aimed to assess public awareness; and estimate prevalence and potential a risk factors of bovine tuberculosis.

Methods

A cross-sectional study was conducted, November 2018 to May 2019, on dairy cattle randomly selected from smallholder farms of Arba Minch Zuria and Chencha districts. Comparative intradermal tuberculin test (CIDT) was used in the diagnosis of bTB in dairy animals. CIDT was administered to 221 dairy cattle. Questionnaire survey was performed on 110 smallholders to assess risk factors accountable for the event of bTB in human population.

Results

8.2% animal level prevalence of bTB was documented in the study sites. Dairy cattle with age of 4 to 8 eight years were 34% more likely to be affected by bTB less than 4 years age cattle (OR=1.34). However, factors like housing, body condition, herd size and parity were not significantly related with the event of bTB. The assessment of bTB awareness was shown 29.7% participants knew that cattle could be infected, and 13.4% of the respondents believed that it can spread from animal to human and vice versa. Besides, 66.1% of participants had habit for consumption of raw milk and soured milk products. Moreover, respondent’s attitude about zoonoses and consequences of bTB was risky.

Conclusion

Present study discloses that bTB is animal health problem affecting dairy cattle in Gamo zone, Southern Ethiopia. Based on the current findings, public awareness creation, bovine tuberculosis test and segregation strategy should be applied to minimize the public health hazards and risk factors for bovine origin tuberculosis.

Pathological, Histological, and Molecular Based Investigations Confirm Novel Mycobacterium bovis Infection in Boselaphus tragocamelus

Mycobacterium bovis (M. bovis) being the main cause of animal tuberculosis is a complex infectious agent and can be a cause of zoonotic tuberculosis zoonosis in public health. To date, the uncommon infection in public health due to M. bovis still is a great challenge to both veterinary and medical professions and requires a careful diagnosis and confirmation of the bacterium. Therefore, this study for the first time reports the clinical, gross, histopathological, and molecular based confirmation of M. bovis infection in wildlife animals (nilgai). Prior to death, the morbid animal showed severe pneumonic ailments like moist cough, thick nasal exudates, and dyspnoea. At necropsy, enlargement of mandibular cervical and mesenteric lymph nodes was observed. Different macroscopic lesions such as congestion and hyperaemia, creamy white and catarrhal exudates in trachea, consolidation, grey and red hepatisation of lungs, and micro- and macrogranulomatous tubercles containing caseous materials in lungs were observed. The heart of morbid animal showed congestions, myocarditis, and a copious amount of straw-colored fluid in the pericardial sac. At the microscopic level, lungs indicated granulomatous inflammatory response, presence of multinucleated giant cells, fibrosis, and punctuation of alveoli with chronic inflammatory cells. Histopathological examination of various sections of the heart of the infected animal showed chronic inflammatory response consisting of chronic inflammatory cells like monocyte, lymphocytes, and fibroblasts along with noncalcified eosinophilic materials. At the molecular level, M. bovis infection was confirmed in various tissues like the heart, lungs, cervical, and mesenteric lymph nodes in morbid animals. In conclusion, based on our results, it can be suggested that more molecular based epidemiological studies are crucial to know the exact cause of pulmonary and cervical tuberculosis in wild animals.

Histopathological Investigations and Molecular Confirmation Reveal Mycobacterium bovis in One-Horned Rhinoceros (Rhinoceros unicorns)

Mycobacterium bovis causes tuberculosis in dairy and wild animals. Presence of tuberculosis in animals poses a threat not only to their herd mates but also for public. No reports are available about the clinical, pathological, and molecular investigation of naturally occurring tuberculosis (TB) due to M. bovis in one-horned rhinoceros. One-horned female rhinoceros (Rhinoceros unicorns) at the age of 41 years died in a public park in Pakistan. Postmortem and other investigations were carried out to know the cause of death. The present study describes necropsy, histopathology, and molecular-based confirmation of TB in a captive female rhinoceros that died of this infection. Clinically, the rhinoceros showed nonspecific clinical signs including anorexia, lethargy, dyspnoea, coughing, and sudden death. At necropsy, the trachea exhibited mild congestion and contained catarrhal exudate at the bronchial bifurcation. Macroscopic examination revealed characteristic tubercles on all parenchymatous organs. The lungs showed consolidation, grey hepatization, and contained granulomatous lesions packed with cheesy exudate. Histopathological examination showed severe pneumonic changes in the form of granulomatous inflammation consisting of lymphocytes, multinucleated giant cells, caseous materials, and mineralized foci surrounded by a fibrous capsule. PCR amplicon of 500 bp confirmed the presence of M. bovis in multiple hepatic and pulmonary tissue samples, as well as in uterine exudates. It was concluded that the presence of tuberculosis in rhinoceros may pose potential transmission risk to other animals and the application of practical tools to determine TB status in the rhinoceros is crucial.

Prevalence of bovine tuberculosis and distribution of tuberculous lesions in cattle slaughtered at Gondar, Northwest Ethiopia

Background

In Ethiopia, bovine tuberculosis (BTB) is a neglected disease that affects the economy and livelihoods of farmers. However, the available data is limited due to insufficient disease surveillance in the country. Therefore; this study aimed to assess the prevalence and distribution of lesions of BTB in cattle slaughtered at Gondar, Northwest Ethiopia.

Methods

Postmortem examinations were used to detect tuberculous lesions, while smear microscopy and histopathology were performed for the identification of acid-fast bacilli (AFB).

Results

Of 497 inspected slaughtered cattle, 45 (9.1%, 95%CI; 0.0668–0.1193) were diagnosed with BTB suggestive tuberculous lesions. A higher proportion of gross lesions was recorded in lymph nodes of lungs; at the mediastinal (14, 31.1%) and bronchial (10, 22.2%) lymph nodes, and followed by mesenteric lymph nodes (9, 20%). Of 45 tuberculous lesions; only 2 (4.4%) were identified as AFB positive by smear microscopy and histopathology. In the overall statistical analysis, body conditions of slaughtered cattle were found to be significantly associated with BTB tuberculous lesions (p < 0.05).

Conclusion

This finding provides the prevalence of BTB and distribution of tuberculous lesions in cattle slaughtered at the abattoir and highlights the need for a practicable control strategy of the disease in the region.

Global prevalence of Mycobacterium bovis infections among human tuberculosis cases: Systematic review and meta-analysis

Tuberculosis (TB) is a chronic communicable bacterial disease caused by Mycobacterium tuberculosis complex (MTBC) species. M. tuberculosis is the main causative agent of human TB, and cattle are the primary host of Mycobacterium bovis; due to close interaction between cattle and humans, M. bovis poses a zoonotic risk. This review summarizes and estimates the prevalence of M. bovis infection among human cases. Studies reporting TB prevalence data that were published in English during 10 years from 20 April 2009 to 17 April 2019 were identified through search of PubMed and other sources. Quality of studies and risk of bias were assessed using standard tools for prevalence study reports. Characteristics of included studies and their main findings were summarized in tables and discussed with narrative syntheses. Meta-analysis was performed on 19 included studies, with a total of 7,185 MTBC isolates identified; 702 (9.7%) of them were characterized as of subspecies M. bovis, but there was a large prevalence difference between the studies, ranging from 0.4% to 76.7%. The genotyping-based studies reported significantly lower prevalence of zoonotic TB than did the studies based on older techniques. The overall pooled prevalence of M. bovis aggregated from all included studies was 12.1% of the total MTBC isolates, while the corresponding pooled figure from the 14 genotyping-based studies was only 1.4%. Generally, human M. bovis cases reported from different countries of the world suggest that the impact of zoonotic TB is still important in all regions. However, it was difficult to understand the true picture of the disease prevalence because of methodological differences. Future investigations on zoonotic TB should carefully consider these differences when evaluating prevalence results.

Diagnostic Challenges and Prospects Associated With Zoonotic Tuberculosis of Central Nervous System

Introduction:

The diagnosis of Tuberculous Meningitis (TBM) has remained a challenge due to its insidious onset and the failure of conventional diagnostic tests. The present study aimed to identify the mycobacterial pathogen in the CSF of patients with TBM and a poor prognosis.

Methods:

We retrospectively recruited 224 TBM and 34 non-TBM patients admitted to the Central India Institute of Medical Sciences, Nagpur, India, in 2014. The CSF samples of these patients were subjected to a duplex PCR assay for the species-specific identification of the causative pathogen.

Results:

M. bovis and infection with M.tuberculosis were detected in 7% (18) and 32.9% (85) of the patients, respectively. Moreover, 14% (36) of the study samples were culture positive; however, the mycobacterial pathogens could not be differentiated to the species level.

Conclusion:

The present study findings emphasized the potentially vital importance of M. bovis identification for appropriate patient management. The obtained data also demonstrated the persistent significance of M. bovis, as a zoonotic pathogen.

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.

Broad diversity of Mycobacterium tuberculosis complex strains isolated from humans and cattle in Northern Algeria suggests a zoonotic transmission cycle

Mycobacterium tuberculosis complex (MTBC) comprises closely related species responsible for human and animal tuberculosis (TB). Efficient species determination is useful for epidemiological purposes, especially for the elucidation of the zoonotic contribution. In Algeria, data on MTBC genotypes are largely unknown. In this study, we aimed to investigate the occurrence and diversity of MTBC genotypes causing human and bovine TB in Northern Algeria. During a two-year sampling period (2017-2019) in two regions of Northern Algeria, we observed an overall prevalence of 6.5% of tuberculosis (TB) among slaughtered cattle, which is higher than previous Algerian data yet comparable to neighboring countries. A total of 296 Mycobacterium tuberculosis complex (MTBC) isolates were genotyped by spoligotyping: 181 from tissues with TB-like lesions collected from 181 cattle carcasses and 115 from TB patients. In human isolates, we identified 107 M. tuberculosis, seven M. bovis and one "M. pinnipedii-like", while for bovine samples, 174 isolates were identified as M. bovis, three as M. caprae, three as "M. pinnipedii-like" and one as "M. microti-like". The majority of isolates (89.2%) belonged to 72 different known Shared International Types (SIT) or M. bovis spoligotypes (SB), while we also identified seven new SB profiles (SB2695 to SB2701). Twenty-eight of the SB profiles were new to Algeria. Our data suggest zoonotic transmission in Sétif, where significantly more TB was observed among cattle (20%) compared to the slaughterhouses from the three other regions (5.4%-7.3%) (p < 0.0001), with the isolation of the same M. bovis genotypes from TB patients. The present study showed a high genetic diversity of MTBC isolated from human and cattle in Northern Algeria. Even though relatively small in terms of numbers, our data suggest the zoonotic transmission of TB from cattle to humans, suggesting the need for stronger eradication strategies for bovine TB.

Bovine tuberculosis at the human-livestock-wildlife interface and its control through one health approach in the Ethiopian Somali Pastoralists: A review

Pastoralism is a way of life in which food supply is produced from animals by using a variety of herding practices based on constant or partial herd mobility in the low land areas of Ethiopia. It covers 12% of the total livestock population and 61% of the total area of land in the country. As a result of their mobile lifestyle, pastoralists are almost completely excluded from the available health services. This review article focuses on bovine tuberculosis in the Ethiopian Somali Pastoralist. It describes Mycobacterium bovis in humans, livestock, and wildlife, and how the disease can be controlled by using One Health approach. Bovine tuberculosis is a chronic bacterial disease caused by Mycobacterium bovis. A study done from 2006 to 2008 on the prevalence of BTB in Ethiopian wildlife showed that sera from 20 of 87 animals (23%) were positive for BTB. In Ethiopia there is no comprehensive report about the status of M. bovis in wildlife populations that often share habitat with livestock. A study done on bovine tuberculosis in Somali pastoral livestock showed low prevalence of the disease. An individual animal prevalence of 2.0%, 0.4%, and 0.2% was reported in cattle, camels, and goats, respectively. In a simultaneous human and cattle study in a pastoralist areas of south-eastern Ethiopia, out of 163 human Mycobacterium tuberculosis complex isolates three were M. bovis. Due to the moderate resistance of the etiological agent to the environmental conditions in one hand and the capacity of its survival in acid milk for not less than 15 days on the other and the habitual consumption of unpasteurized milk by humans make this disease a vital zoonosis in Somali pastoralists in Ethiopia. M. bovis is a pathogen at the human-livestock-wildlife interface. Diseases transmitted between humans, livestock, and wildlife are increasingly challenging public and veterinary health systems. Therefore, studies concerning the burden of the diseases in wildlife, livestock and human beings in Somali Pastoralists should be undertaken. A One Health approach that takes the wellbeing of the pastoralists, the health of their livestock and environment into consideration is also necessary for the control of BTB.

Risk Factors for Zoonotic Tuberculosis at the Wildlife-Livestock-Human Interface in South Africa

A cross-sectional study was conducted to investigate the risk factors associated with zoonotic tuberculosis in humans and its transmission to people living at the wildlife–livestock–human interface. A questionnaire was administered to collect information on food consumption habits, food handling practices, and knowledge of zoonotic TB. Sputum samples were also collected from 150 individuals that belonged to households of cattle farmers with or without a bTB infected herd. In addition, 30 milk samples and 99 nasal swabs were randomly collected from cattle in bTB infected herds for isolation of Mycobacterium bovis (M. bovis). The sputum samples were screened for TB using the GeneXpert test and this was followed by mycobacterial culture and speciation using molecular techniques. No M. bovis was isolated from TB positive sputum samples and only one sample was confirmed as Mycobacterium tuberculosis (M. tuberculosis). M. bovis was isolated from 6.6% (n = 2/30) milk samples and 9% (n = 9/99) of nasal swabs. Ownership of a bTB infected herd and consumption of milk were recognized as highly significant risk factors associated with a history of TB in the household using multiple correspondence analysis (MCA) and logistic regression. The findings from this study have confirmed the potential for zoonotic TB transmission via both unpasteurized milk and aerosol thus, the role of M. bovis in human TB remains a concern for vulnerable communities.

Epidemiology of tuberculous lymphadenitis in Africa: A systematic review and meta-analysis

INTRODUCTION

Tuberculous lymphadenitis is the most frequent form of extra-pulmonary TB (EPTB) and accounts for a considerable proportion of all EPTB cases. We conducted a systematic review of articles that described the epidemiological features of TBLN in Africa.

METHODS

Any article that characterized TBLN cases with respect to demographic, exposure and clinical features were included. Article search was restricted to African countries and those published in English language irrespective of publication year. The articles were retrieved from the electronic database of PubMed, Scopus, Cochrane library and Lens.org. Random effect pooled prevalence with 95% CI was computed based on Dersimonian and Laird method. To stabilize the variance, Freeman-Tukey double arcsine root transformation was done. The data were analyzed using Stata 14.

RESULTS

Of the total 833 articles retrieved, twenty-eight articles from 12 African countries fulfilled the eligibility criteria. A total of 6746 TBLN cases were identified. The majority of the cases, 4762 (70.6%) were from Ethiopia. Over 77% and 88% of identified TBLN were cervical in type and naïve to TB drugs. Among the total number of TBLN cases, 53% were female, 68% were in the age range of 15-44 years, 52% had a history of livestock exposure, 46% had a history of consuming raw milk/meat and 24% had history of BCG vaccination. The proportion of TBLN/HIV co-infection was much lower in Ethiopia (21%) than in other African countries (73%) and the overall African estimate (52%). Fever was recorded in 45%, night sweating in 55%, weight loss in 62% and cough for longer than two weeks in 32% of the TBLN cases.

CONCLUSIONS

TBLN was more common in females than in males. The high prevalence of TBLN in Ethiopia did not show directional correlation with HIV. Population based prospective studies are warranted to better define the risk factors of TBLN in Africa.

Comparative proteomics identified immune response proteins involved in response to vaccination with heat-inactivated Mycobacterium bovis and mycobacterial challenge in cattle

There is an imperative need for effective control of bovine tuberculosis (BTB) on a global scale and vaccination of cattle may prove to be pivotal in achieving this. The oral and parenteral use of a heat-inactivated Mycobacterium bovis (M. bovis) vaccine has previously been found to confer partial protection against BTB in several species. A role for complement factor C3 has been suggested in wild boar, but the exact mechanism by which this vaccine provides protection remains unclear. In the present study, a quantitative proteomics approach was used to analyze the white blood cell proteome of vaccinated cattle in comparison to unvaccinated controls, prior (T0) and in response to vaccination, skin test and challenge (T9 and T12). The Fisher's exact test was used to compare the proportion of positive reactors to standard immunological assays for BTB (the BOVIGAM^® assay, IDEXX TB ELISA and skin test) between the vaccinated and control groups. Using reverse-phase liquid-chromatography tandem mass spectrometry (RP-LC-MS/MS), a total of 12,346 proteins were identified with at least two peptides per protein and the Chi²-test (P = 0.05) determined 1,222 to be differentially represented at the key time point comparisons. Gene ontology (GO) analysis was performed in order to determine the biological processes (BPs), molecular functions (MFs) and cell components (CCs) the proteins formed part of. The analysis was focused on immune system BPs, specifically. GO analysis revealed that the most overrepresented proteins in immune system BPs, were kinase activity and receptor activity molecular functions and extracellular, Golgi apparatus and endosome cell components and included complement factor C8α and C8β as well as toll-like receptors 4 (TLR4) and 9 (TLR9). Proteins of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) (JAK-STAT) and protein kinase C (PKC) signaling pathways were furthermore found to potentially be involved in the immune response elicited by the inactivated vaccine. In conclusion, this study provides a first indication of the role of several immune system pathways in response to the heat-inactivated M. bovis vaccine and mycobacterial challenge.

Epidemiology of Mycobacterium bovis and Mycobacterium tuberculosis in animals: Transmission dynamics and control challenges of zoonotic TB in Ethiopia

Mycobacterium tuberculosis complex is the cause of tuberculosis (TB) in humans and other animals. Specifically, Mycobacterium bovis (M. bovis) and Mycobacterium tuberculosis (M. tuberculosis) are highly pathogenic mycobacteria that may infect different animal species and are the sources of TB in humans. The objective of this paper was to review the epidemiology of M. bovis and M. tuberculosis in animals. The review also highlighted the transmission dynamics of M. bovis and M. tuberculosis in humans and animals and control challenges of zoonotic TB in Ethiopia. The literature review focused on scientific peer-reviewed articles from studies exclusively conducted in Ethiopia that were published from 1998 to 2017. Husbandry system, breed and herd size have significant role in the epidemiology of bovine tuberculosis (BTB) in Ethiopia. The information presented reveals that different strains of M. bovis are widely distributed in domestic animals predominantly in the Ethiopian cattle and the main strain was found to be SB1176. In addition, the isolation of M. tuberculosis from domestic animals in different settings signifies the circulation of the agent between humans and animals in Ethiopia. The life styles of the Ethiopian communities, close contact with domestic animals and/or the habit of consuming raw animal products, are suggested as the main factors for transmission of M. bovis and M. tuberculosis between human and animal which may have impact on the TB control program in human. In Ethiopia, a human TB control program has been widely implemented, however, the role of animal in the transmission of the causative agent has been neglected which could be one of the challenges for an effective control program. This warrants the need for incorporating animal TB control programs using "One Health" approach for effective TB control for both human and animal.

The predominance of Ethiopian specific Mycobacterium tuberculosis families and minimal contribution of Mycobacterium bovis in tuberculous lymphadenitis patients in Southwest Ethiopia

BACKGROUND

Ethiopia has an extremely high rate of extrapulmonary tuberculosis, dominated by tuberculous lymphadenitis (TBLN). However, little is known about Mycobacterium tuberculosis complex (MTBc) lineages responsible for TBLN in Southwest Ethiopia.

METHODS

A total of 304 MTBc isolates from TBLN patients in Southwest Ethiopia were genotyped primarily by spoligotyping. Isolates of selected spoligotypes were further analyzed by 15-loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) (n=167) and qPCR-based single nucleotide polymorphism (n=38). Isolates were classified into main phylogenetic lineages and families by using the reference strain collections and identification tools available at MIRU-VNTRplus data base. Resistance to rifampicin was determined by Xpert MTB/RIF.

RESULTS

The majority of isolates (248; 81.6%) belonged to the Euro-American lineage (Lineage 4), with the ill-defined T and Haarlem as largest families comprising 116 (38.2%) and 43 (14.1%) isolates respectively. Of the T family, 108 isolates were classified as being part of the newly described Ethiopian families, namely Ethiopia_2 (n=44), Ethiopia_3 (n=34) and Ethiopia_H₃₇Rv-like (n=30). Other sub-lineages included URAL (n=18), S (n=17), Uganda I (n=16), LAM (n=13), X (n=5), TUR (n=5), Uganda II (n=4) and unknown (n=19). Lineage 3 (Delhi/CAS) was the second most common lineage comprising 44 (14.5%) isolates. Interestingly, six isolates (2%) were belonged to Lineage 7, unique to Ethiopia. Lineage 1 (East-African Indian) and Lineage 2 (Beijing) were represented by 3 and 1 isolates respectively. M. bovis was identified in only two (0.7%) TBLN cases. The cluster rate was highest for Ethiopia_3 isolates showing clonal similarity with isolates from North Ethiopia. Lineage 3 was significantly associated with rifampicin resistance.

CONCLUSIONS

In TBLN in Southwest Ethiopia, the recently described Ethiopia specific Lineage 4 families were predominant, followed by Lineage 3 and Lineage 4-Haarlem. The contribution of M. bovis in TBLN infection is minimal.

Evaluation of complementary diagnostic tools for bovine tuberculosis detection in dairy herds from India

Aim:

A cross-sectional study was undertaken to know the herd prevalence and evaluate the single intradermal tuberculin testing (SITT), culture isolation, and polymerase chain reaction (PCR) analysis for the diagnosis of bovine tuberculosis (TB).

Materials and Methods:

A total of 541 cows of three dairy farms of Bareilly and Mukteshwar were screened by SITT followed by collection of pre-scapular lymph node (PSLN) aspirates (71), milk (54), and blood (71) samples from reactor animals. These clinical samples were processed for culture isolation and direct PCR-based identification and species differentiation.

Results:

Out of 541 cows screened by SITT, 71 (13.12%) animals were found positive. Mycobacteria were isolated from 3 (4.22%) PSLN aspirate but not from any cultured milk and blood samples. 28 (39.43%) PSLN aspirate and 5 (9.25%) milk samples were positive for Mycobacterium TB (MTB) complex (MTC) by PCR amplification for the IS6110 insertion sequence; however, blood samples were found negative. For species differentiation, multiplex-PCR using 12.7 kb primers was conducted. Out of 28 PSLN aspirate, Mycobacterium bovis was detected in 18 (64.28%) and MTB in 8 (28.57%), whereas 2 aspirate samples (7.14%) were positive for both the species. All the five milk positive samples were positive for M. bovis.

Conclusion:

Direct detection of bovine TB by a molecular-based method in dairy animals after preliminary screening was appeared to be more sensitive and specific compared to the conventional method (i.e., culture isolation). Its application in form of serial testing methodology for the routine diagnosis and thereafter, culling of infected stock may be suggested for the control programs in dairy herds. The PSLN aspirate was found to be the most suitable specimen for culture isolation and PCR-based detection of Mycobacterium spp. among live infected animals.

Tuberculous Lymphadenitis in South-Eastern Nigeria; A 15 Years Histopathologic Review (2000-2014)

BACKGROUND

The human immunodeficiency virus (HIV) pandemic has brought about a resurgence in tuberculosis (TB), especially in developing countries. Previous studies on TB lymphadenitis (TBLN) in South-Eastern Nigeria were done before the advent of the HIV pandemic making a review pertinent.

AIM

To evaluate the role of TBLN as a cause of superficial lymphadenopathy in the post-HIV/acquired immune deficiency syndrome (AIDS) era of South-Eastern Nigeria.

MATERIALS AND METHODS

This is a 15 years (2000-2014) retrospective review of all superficial lymph node biopsies (SLNBs) received at the Department of Morbid Anatomy, University of Nigeria Teaching Hospital, Ituku-Ozalla Enugu, Nigeria.

RESULTS

One hundred and seventy-two cases of TBLN were identified in this study constituting 14.6% (172/1,180) of SLNBs received at our Hospital's Morbid Anatomy Department during the 15 years period under review. Twenty-eight cases of TBLN were clinically screened for HIV, 23 of which tested positive, representing 82.1% (23/28) of clinically screened cases. Acid fast bacilli demonstration was positive in 15.1% (26/172) of cases using Ziehl-Neelsen stain. 48.8% (84/172) of TBLN cases were males, and 51.2% (88/172) were females with most (22) cases received in 2012 and least (5) cases in 2000. Most TBLN occurred in the 21-25 years age group with a total of 21.5% (37/172) of cases and a male to female ratio of 1:1.5 The most common biopsy site for TBLN was the cervical group followed by the axillary and inguinal groups with 73.8% (127/172), 14% (24/172), and 4.7% (8/172) of cases, respectively.

CONCLUSIONS

There is a remarkable decline in the prevalence of TB lymphadenitis in South-Eastern Nigeria indicating a change in trend from the pre- to the post-HIV/AIDS era with slightly more females now presenting with TBLN and most TB lymphadenitis patients now presenting with associated HIV/AIDS disease. There is an urgent need to provide modern diagnostic facilities in our medical laboratories.

Comparative Evaluation of Several Gene Targets for Designing a Multiplex-PCR for an Early Diagnosis of Extrapulmonary Tuberculosis

PURPOSE

Diagnosis of extrapulmonary tuberculosis (EPTB) poses serious challenges. A careful selection of appropriate gene targets is essential for designing a multiplex-polymerase chain reaction (M-PCR) assay.

MATERIALS AND METHODS

We compared several gene targets of Mycobacterium tuberculosis, including IS6110, devR, and genes encoding MPB-64 (mpb64), 38kDa (pstS1), 65kDa (hsp65), 30kDa (fbpB), ESAT-6 (esat6), and CFP-10 (cfp10) proteins, using PCR assays on 105 EPTB specimens. From these data, we chose the two best gene targets to design an M-PCR.

RESULTS

Among all gene targets tested, mpb64 showed the highest sensitivity (84% in confirmed cases and 77.5% in clinically suspected cases), followed by IS6110, hsp65, 38kDa, 30kDa, esat6, cfp10, and devR. We used mpb64+IS6110 for designing an M-PCR assay. Our M-PCR assay demonstrated a high sensitivity of 96% in confirmed EPTB cases and 88.75% in clinically suspected EPTB cases with a high specificity of 100%, taking clinical diagnosis as the gold standard.

CONCLUSION

These M-PCR results along with the clinical findings may facilitate an early diagnosis of EPTB patients and clinical management of disease.

Mycobacterium tuberculosis causing tuberculous lymphadenitis in Maputo, Mozambique

Background

The zoonosis bovine tuberculosis (TB) is known to be responsible for a considerable proportion of extrapulmonary TB. In Mozambique, bovine TB is a recognised problem in cattle, but little has been done to evaluate how Mycobacterium bovis has contributed to human TB. We here explore the public health risk for bovine TB in Maputo, by characterizing the isolates from tuberculous lymphadenitis (TBLN) cases, a common manifestation of bovine TB in humans, in the Pathology Service of Maputo Central Hospital, in Mozambique, during one year.

Results

Among 110 patients suspected of having TBLN, 49 had a positive culture result. Of those, 48 (98 %) were positive for Mycobacterium tuberculosis complex and one for nontuberculous mycobacteria. Of the 45 isolates analysed by spoligotyping and Mycobacterial Interspersed Repetitive Unit – Variable Number Tandem Repeat (MIRU-VNTR), all were M. tuberculosis. No M. bovis was found.

Cervical TBLN, corresponding to 39 (86.7 %) cases, was the main cause of TBLN and 66.7 % of those where from HIV positive patients.

We found that TBLN in Maputo was caused by a variety of M. tuberculosis strains. The most prevalent lineage was the EAI (n = 19; 43.2 %). Particular common spoligotypes were SIT 48 (EAI1_SOM sublineage), SIT 42 (LAM 9), SIT 1 (Beijing) and SIT53 (T1), similar to findings among pulmonary cases.

Conclusions

M. tuberculosis was the main etiological agent of TBLN in Maputo. M. tuberculosis genotypes were similar to the ones causing pulmonary TB, suggesting that in Maputo, cases of TBLN arise from the same source as pulmonary TB, rather than from an external zoonotic source. Further research is needed on other forms of extrapulmonary TB and in rural areas where there is high prevalence of bovine TB in cattle, to evaluate the risk of transmission of M. bovis from cattle to humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-015-0603-5) contains supplementary material, which is available to authorized users.

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

INTRODUCTION

The diagnosis of tuberculous lymphadenitis (TBL) remains challenging. The routinely used methods (cytology and smear microscopy) have sub-optimal sensitivity. Recently, WHO recommends GeneXpert to be used as the initial diagnostic test in patients suspected of having extra-pulmonary tuberculosis (EPTB). However, this was a conditional recommendation due to very low-quality evidence available and more studies are needed. In this study we evaluated the performance of Xpert for the diagnosis of TBL on concentrated fine needle aspirates (FNA) in Southwest Ethiopia.

METHODS

FNA was collected from presumptive TBL cases. Two smears were prepared from each aspirate and processed for cytology and conventional microscopy. The remaining aspirate was treated with N-acetyl-L-cysteine-NaOH and centrifuged for 15minutes at 3000g. The concentrated sediment was used for culture and Xpert test. Capilia TB-Neo test was used to differentiate M. tuberculosis complex (MTBC) from non-tuberculous mycobacteria (NTM). Composite bacteriological methods (culture and/or smear microscopy) were considered as a reference standard.

RESULT

Out of 143 enrolled suspects, 64.3% (92/143) were confirmed TBL cases by the composite reference standard (CRS). Xpert detected M. tuberculosis complex (MTBC) in 60.1% (86/143) of the presumptive TBL cases. The sensitivity of Xpert compared to CRS was 87.8% [95% CI: 81.0-94.5] and specificity 91.1% [95% CI: 82.8-99.4]. The sensitivity was 27.8% for smear microscopy and 80% for cytology compared to CRS. Cytology showed the lowest specificity (57.8%). Xpert was positive in 4 out of 45 culture- and smear-negative cases. Among 47 cytomorphologically non-TBL cases, 15 were positive on Xpert. More than half of Xpert-positive cases were in the range of very low cut-off threshold values (28

CONCLUSION

Xpert test showed a high sensitivity and specificity for the diagnosis of TBL on concentrated FNA samples. In addition, Xpert offered rapid detection of rifampicin-resistant M. tuberculosis strains from lymph node aspirates.

Collapse

Key Words Collapse

MESH Headings

• Adolescent
• Adult
• Bacteriological Techniques/methods
• Biopsy, Fine-Needle
• Ethiopia
• Female
• Humans
• Lymph Nodes/microbiology
• Lymph Nodes/pathology
• Male
• Middle Aged
• Mycobacterium tuberculosis/chemistry
• Mycobacterium tuberculosis/cytology
• Prognosis
• Rifampin/chemistry
• Sputum/microbiology
• Tuberculosis, Lymph Node/diagnosis
• Young Adult

Collapse

Grants Collapse

Affiliation(s)

Mulualem Tadesse Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia Mycobacteriology Research Center, Institute of Biotechnology Research, Jimma University, Jimma, Ethiopia Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
Gemeda Abebe Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia Mycobacteriology Research Center, Institute of Biotechnology Research, Jimma University, Jimma, Ethiopia
Ketema Abdissa Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia
Dossegnaw Aragaw Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia Mycobacteriology Research Center, Institute of Biotechnology Research, Jimma University, Jimma, Ethiopia
Kedir Abdella Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia Mycobacteriology Research Center, Institute of Biotechnology Research, Jimma University, Jimma, Ethiopia
Alemayehu Bekele Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia
Mesele Bezabih Department of Medical Laboratory Sciences and Pathology, Jimma University, Jimma, Ethiopia
Ludwig Apers Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
Bouke C. de Jong Mycobacteriology Unit, Department of Microbiology, Institute of Tropical Medicine, Antwerp, Belgium
Leen Rigouts Mycobacteriology Unit, Department of Microbiology, Institute of Tropical Medicine, Antwerp, Belgium Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium

Collapse

Predominance of Uganda genotype of Mycobacterium tuberculosis isolated from Ugandan patients with tuberculous lymphadenitis

Background

In Uganda, the emerging Uganda genotype of Mycobacterium tuberculosis is the most common cause of pulmonary tuberculosis (PTB), and accounts for up to 70 % of isolates. Extrapulmonary TB (EPTB) is less studied in Uganda.

Methods

Molecular characterization using deletion analysis and spoligotyping was performed on 121 M. tuberculosis isolates from lymph node fine needle biopsy aspirates of Ugandan patients with tuberculous lymphadenitis. The evolutionary relationships and worldwide distribution of the spoligotypes were analyzed.

Results

Mycobacterium tuberculosis was the only cause of EPTB in this study. The T2 sublineage was the most predominant lineage and the Uganda genotype was the dominant genotype. There were 54 spoligotype patterns among the 121 study isolates. The dominant spoligotypes were shared international types (SIT) SIT420, SIT53, SIT 135, SIT 128 and SIT590 in descending order. All but SIT420 were previously reported in pulmonary TB in this setting. The phylogenetic analysis showed a long descendant branch of spoligotypes belonging to the T2-Uganda sublineage containing specifically SITs 135, 128 and 420.

Conclusion

In most cases, the spoligotypes were similar to those causing PTB, but the Uganda genotype was found to be less common in EPTB than previously reported for PTB in Uganda. The phylogenetic analysis and the study of the worldwide distribution of clustered spoligotypes indicate an ongoing evolution of the Uganda genotype, with the country of Uganda at the center of this evolution.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1362-y) contains supplementary material, which is available to authorized users.

[Extrapulmonary tuberculosis]

Each year, there are more than eight million new cases of tuberculosis and 1.3 million deaths. There is a renewed interest in extrapulmonary forms of tuberculosis as its relative frequency increases. Among extrapulmonary organs, pleura and lymph nodes are the most common. Their diagnosis is often difficult and is based on clinical, radiological, bacteriological and histological findings. Extrapulmonary lesions are paucibacillary and samplings, in most cases, difficult to obtain, so diagnosis is often simply presumptive. Nucleic acid amplification tests, which are fast and specific, have greatly facilitated the diagnosis of some forms of extrapulmonary tuberculosis. However, their sensitivity is poor and a negative test does not eliminate the diagnosis. Treatment is the same as for pulmonary forms, but its duration is nine to 12 months for central nervous system and for bone tuberculosis. Corticosteroids are indicated in meningeal and pericardial localizations. Complementary surgery is used for certain complicated forms.

Bacteriological methods as add on tests to fine-needle aspiration cytology in diagnosis of tuberculous lymphadenitis: can they reduce the diagnostic dilemma?

BACKGROUND

The diagnostic accuracy of fine-needle aspiration (FNA) cytology for the diagnosis of tuberculous lymphadenitis (TBLN) is confounded by mimicking cytomorphologic disorders. The objective of this study was to determine whether supplementing FNA cytology with bacteriological methods improves the overall accuracy of TBLN diagnosis.

METHODS

Two hundred presumptive TBLN cases were included in the study. FNA specimens were collected and examined for cytomorphologic changes, for acid-fast bacilli (AFB) by microscopy and for mycobacterial growth on culture. Culture was done using Lowenstein-Jensen (LJ) medium and mycobacteria growth indicator tube (BACTEC MGIT 960 TB detection system). Differentiation between M. tuberculosis complex (MTBc) and non-tuberculous mycobacteria (NTM) was done by using 500 μg/ml para-nitrobenzoic acid (PNB) susceptibility testing.

RESULTS

Cytomorphology detected TBLN among 80% (160/200) of the presumptive cases. Culture results were available for 188 cases. Twelve samples were excluded due to contamination on both culture methods. Culture confirmed cases accounted for 78% (147/188) of which MTBc constituted 97.3% (143/147). Among presumptive cases, classified by FNA cytology as 'abscess', 11 were culture positive. Microscopy detected 31.3% (46/147) of culture confirmed mycobacterial lymphadenitis of which 11% (4/37) were diagnosed non-suggestive for tuberculosis (TB) by FNA cytology. Compared to culture (LJ & BACTEC MGIT 960) and AFB microscopy as composite gold standard, FNA cytology had a sensitivity of 88.4% and a specificity of 48.8%. The positive predictive value was 86.1% while the negative predictive value was 54.1%. The confirming power and the ROC curve area was 1.73 and 0.69, respectively.

CONCLUSION

FNA cytology showed a relatively high sensitivity but a low specificity. Combining bacteriological methods with FNA cytology in an endemic region like Ethiopia improves the overall accuracy of the diagnosis of mycobacterial lymphadenitis, which in turn may lead to better patient management.

Documentation and treatment outcomes of smear-negative and extra-pulmonary tuberculosis in Ethiopia

BACKGROUND

Smear-negative and extra-pulmonary tuberculosis (TB) comprise two thirds of TB cases reported in Ethiopia. Neither treatment outcomes nor underlying associated factors are routinely reported for these cases.

OBJECTIVE

To assess treatment outcomes and associated risk factors of smear-negative and extra-pulmonary TB in comparison with smear-positive cases.

DESIGN

Record review of all TB cases registered in 14 randomly selected public and private health facilities in Addis Ababa, Ethiopia, over a 1-year period.

RESULTS

Percentages of smear-negative and extra-pulmonary TB were independent of human immunodeficiency virus (HIV) status, and were not evenly distributed among health facilities. Extra-pulmonary TB was overrepresented in the private sector, and smear-negative TB was more frequent in health clinics than in hospitals. Outcomes reported by clinics were more favourable than those of the hospitals; no differences were observed when comparing public and private health facilities. Only 54% of the TB registers were complete; missing information correlated with unfavourable outcomes. Younger age, but not sex or HIV status, was associated with favourable outcomes.

CONCLUSION

The uneven distribution of smear-negative and extra-pulmonary TB among different health facilities requires further study and may provide important insight into diagnosis and care of these patients. Incomplete TB register information may be an underappreciated factor contributing to unfavourable outcomes.

Multiplex-PCR for differentiation of Mycobacterium bovis from Mycobacterium tuberculosis complex

We evaluated a multiplex-PCR to differentiate Mycobacterium bovis from M. tuberculosis Complex (MTC) by one step amplification based on simultaneous detection of pncA 169C > G change in M. bovis and the IS6110 present in MTC species. Our findings showed the proposed multiplex-PCR is a very useful tool for complementation in differentiating M. bovis from other cultured MTC species.

Diagnostic performance of the Xpert MTB/RIF assay for tuberculous lymphadenitis on fine needle aspirates from Ethiopia

The Xpert MTB/RIF (Xpert) test is a novel automated molecular diagnostic recently endorsed by the World Health Organization for rapid diagnosis of tuberculosis (TB). Nevertheless, performance related data from high TB prevalence regions to investigate clinically suspected TB lymphadenitis are limited. To evaluate the performance of Xpert test for direct detection of the Mycobacterium tuberculosis complex (MTBC) and rifampicin (RIF) resistance in lymph node aspirates, a cross-sectional study was conducted at four main hospitals in northern Ethiopia. Culture served as a reference standard for growth of MTBC and phenotypic and MTBDRplus drug susceptibility testing for detecting RIF resistance. Two-hundred-thirty-one fine needle aspirate (FNAs) specimens were processed simultaneously for smear, culture, and Xpert test. When compared to culture, the Xpert test correctly identified 29 out of 32 culture positive cases, 5 out of 11 contaminated cases, and 56 out of 188 culture negative cases. The overall sensitivity of the test was 93.5% [95% CI, 78.3-98.9%] and specificity 69.2% [95% CI, 66.4-70.0%]. The Xpert test identified the rpoB mutations associated with RIF resistance concordant with GenoType MTBDRplus and phenotypic drug susceptibility testing. In conclusion, the Xpert assay was found to perform well in detecting MTBC and RIF resistance in TB lymphadenitis patients. Furthermore, the test is simple and suitable to use in remote and rural areas for the diagnosis of TB lymphadenitis directly from FNAs in Ethiopia where TB/MDR-TB is rampant.

Use of endo-ovarian tissue biopsy and pelvic aspirated fluid for the diagnosis of female genital tuberculosis by conventional versus molecular methods

BACKGROUND

Til date, none of the diagnostic techniques available for the detection of female genital tuberculosis (FGTB) are 100% accurate. We therefore, proposed to use the endometrial tissue biopsies (ETBs), ovarian tissue biopsies (OTBs) and pelvic aspirated fluids (PAFs) for the diagnosis of FGTB among infertile women by conventional versus molecular methods.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 302 specimens were collected both from 202 infertile women highly suspected of having FGTB on laparoscopy examination and 100 control women of reproductive age. Out of 302 specimens, 150 (49.67%) were ETBs, 95 (31.46%) were OTBs and 57 (18.87%) were PAFs. All specimens were tested by conventional techniques, later compared with multi-gene PCR for the detection of Mycobacterium tuberculosis (MTB) and correlated with laparoscopic findings. The presence of MTB DNA was observed in 49.5% of ETBs, 33.17% of OTBs and 5.44% of PAF specimens collected from highly suspected FGTB patients. All women of control group were confirmed as negative for tuberculosis. The conventional methods showed 99% to 100% specificity with a low sensitivity, ranging from 21.78% to 42.08% while hematoxylin and eosin staining showed a sensitivity of 51.48%. Multi-gene PCR was found to have much higher sensitivity of 70.29% with MTB64 gene, 86.63% with 19 kDa antigen gene at species and TRC4 element at regional MTB complex and 88.12% with 32 kDa protein gene at genus level. The specificity of multi-gene PCR was 100%. Compared with culturing and Ziehl-Neelsen's staining, multi-gene PCR demonstrated improvement in the detection of FGTB (χ2 = 214.612, 1 df, McNemar's test value <0.0001).

CONCLUSIONS SIGNIFICANCE

We suggest site specific sampling, irrespective of sample type and amplification of the 19 kDa antigen gene in combination with TRC4 element as a successful multi-gene PCR for the diagnosis of FGTB and differentiation of mycobacterial infection among endo-ovarian tissue biopsies and PAFs taken from infertile women.

Strain diversity of Mycobacterium tuberculosis isolates from pulmonary tuberculosis patients in Afar pastoral region of Ethiopia

Data on genotypic diversity of Mycobacterium tuberculosis complex (MTBC) is important to understand its epidemiology, human adaptation, clinical phenotypes, and drug resistance. This study aimed to characterize MTBC clinical isolates circulating in a predominantly pastoralist area in Ethiopia, a country where tuberculosis is the second leading cause of mortality. Culture of sputum samples collected from a total of 325 pulmonary TB suspects was done to isolate MTBC. Spoligotyping was used to characterize 105 isolates from culture positive slopes and the result was compared with an international database. Forty-four spoligotype patterns were observed to correspond to 35 shared-types (SITs) containing 96 isolates and 9 orphan patterns; 27 SITs containing 83 isolates matched a preexisting shared-type in the database, whereas 8 SITs (n = 13 isolates) were newly created. A total of 19 SITs containing 80 isolates were clustered within this study (overall clustering of 76.19%). Three dominant lineages (T, CAS, and Manu) accounted for 76.19% of the isolates. SIT149/T3-ETH was one of the two most dominant sublineages. Unlike previous reports, we show that Manu lineage strains not only constitute a dominant lineage, but are also associated with HIV infection in Afar region of Ethiopia. The high level of clustering suggests the presence of recent transmission that should be further studied using additional genotyping markers.

Tuberculous lymphadenitis in Northern Ethiopia: in a public health and microbiological perspectives

Background

The actual burden and causative agent of tuberculous lymphadenitis (TBLN) cases is not well known due to lack of strong surveillance system and diagnostic facilities in Ethiopia. This study was conducted to determine the prevalence of TBLN, its causative agent and risk factors for acquiring this infection.

Methods

A cross-sectional study was conducted from April to May 2012 at four main hospitals and one diagnostic clinic located in northern Ethiopia. Fine needle aspirates (FNAs) from TBLN suspects were taken for acid fast bacilli (AFB) microscopy, culture and molecular typing.

Results

Among 437 aspirates, culture yielded AFB in 226 (51.7%) of cases. Sixty one culture negative cases (30.5% of 200 cases) were positive by Xpert MTB/RIF test. Moreover, a rifampicin resistant AFB was detected from culture negative cases. The overall prevalence of FNAs positive TBLN cases was 65.8 %. The BacT/AlerT 3D system proved to be a more rapid method with higher recovery rate than Lowenstein-Jensen (L-J) and/or Gottsacker media (P<0.0001). Molecular typing identified all culture positive isolates as M.tuberculosis. The main risk factors for TBLN were pediatric age (OR 2.8, 95% CI, 1.09- 7.05) and cough (OR 2, 95%CI, 1.09-3.7).

Conclusions

The results of this study revealed a high prevalence of TBLN in the study sites and that pediatric age and cough are key predictors of the disease. TBLN is an important public health problem that needs to be addressed in the area. It is important to note that MDR strains of TB could be involved and aetiological confirmation and drug sensitivity testing of TBLN isolates should be expanded. Further studies on the M.tuberculosis lineages, circulating strains and transmission dynamics, are recommended.

Mycobacterial lineages causing pulmonary and extrapulmonary tuberculosis, Ethiopia

Molecular typing of 964 specimens from patients in Ethiopia with lymph node or pulmonary tuberculosis showed a similar distribution of Mycobacterium tuberculosis strains between the 2 disease manifestations and a minimal role for M. bovis. We report a novel phylogenetic lineage of M. tuberculosis strongly associated with the Horn of Africa.

Transmission of Mycobacterium tuberculosis between farmers and cattle in central Ethiopia

Background

Transmission of Mycobacterium tuberculosis (M. tuberculosis) complex could be possible between farmers and their cattle in Ethiopia.

Methodology/Principal Findings

A study was conducted in mixed type multi-purposes cattle raising region of Ethiopia on 287 households (146 households with case of pulmonary tuberculosis (TB) and 141 free of TB) and 287 herds consisting of 2,033 cattle belonging to these households to evaluate transmission of TB between cattle and farmers. Interview, bacteriological examinations and molecular typing were used for human subjects while comparative intradermal tuberculin (CIDT) test, post mortem and bacteriological examinations, and molecular typing were used for animal studies. Herd prevalence of CIDT reactors was 9.4% and was higher (p<0.01) in herds owned by households with TB than in herds owned by TB free households. Animal prevalence was 1.8% and also higher (p<0.01) in cattle owned by households with TB case than in those owned by TB free households. All mycobacteria (141) isolated from farmers were M. tuberculosis, while only five of the 16 isolates from cattle were members of the M. tuberculosis complex (MTC) while the remaining 11 were members of non-tuberculosis mycobacteria (NTM). Further speciation of the five MTC isolates showed that three of the isolates were M. bovis (strain SB1176), while the remaining two were M. tuberculosis strains (SIT149 and SIT53). Pathology scoring method described by “Vordermeier et al. (2002)” was applied and the average severity of pathology in two cattle infected with M. bovis, in 11 infected with NTM and two infected with M. tuberculosis were 5.5, 2.1 and 0.5, respectively.

Conclusions/Significance

The results showed that transmission of TB from farmers to cattle by the airborne route sensitizes the cows but rarely leads to TB. Similarly, low transmission of M. bovis between farmers and their cattle was found, suggesting requirement of ingestion of contaminated milk from cows with tuberculous mastitis.

Fine-needle aspiration cytology in Ethiopia

CONTEXT

Most of the population in Ethiopia lives below the poverty line with severely limited access to health care. The burden of infectious diseases is high, but benign and malignant neoplasms are also encountered frequently. For diagnosis of palpable lesions in this setting, fine-needle aspiration biopsy is the method of choice.

OBJECTIVE

To present findings from several patients from 3 major hospitals in Ethiopia who underwent fine-needle aspiration biopsy.

DATA SOURCES

Representative cytopathology cases of routinely encountered problems are shown. Often patients present with clinically advanced lesions. Staffing, technique, and equipment used for fine-needle aspiration biopsy are described at Black Lion Hospital (Addis Ababa), the University of Gonder Hospital (Gonder), and Ayder Referral Hospital of Mekelle University in the Tigray region of northern Ethiopia.

CONCLUSIONS

Fine-needle aspiration biopsy is a highly effective method for diagnosis of mass lesions, especially in an environment with sparse health care resources, such as Ethiopia. This article illustrates the work of Ethiopian cytopathologists and emphasizes the constraints under which they perform their work.

Molecular typing of mycobacteria isolated from extrapulmonary tuberculosis patients at Debre Birhan Referral Hospital, central Ethiopia

BACKGROUND

Extrapulmonary tuberculosis (EPTB) constitutes about 10% to 20% of all cases of tuberculosis in immunocompetent patients and more than 50% of the cases in HIV-positive individuals worldwide. Little information is available on the clonal diversity of Mycobacterium species in Ethiopia from EPTB.

METHODS

This study was carried out on smear-negative EPTB patients to molecularly characterize Mycobacterium tuberculosis complex strains. A questionnaire, smear staining, culture, deletion typing, and spoligotyping were employed.

RESULTS

The proportional distribution of EPTB and isolates did not vary substantially (p > 0.05) amongst the socio-demographic parameters considered in the current investigation. Out of 98 fine needle aspirates processed for culture, 36.7% (36/98) were positive for mycobacterial growth. Further speciation of those culture-positive isolates showed that 88.9% were M. tuberculosis and the remaining could be non-tuberculous mycobacterial species. Spoligotyping revealed 16 clusters out of which 2 were new to the SITVIT database. The most dominant spoligotypes were SIT54, SIT53, and SIT149 in decreasing order. SIT54, SIT134, SIT173, SIT345, SIT357, SIT926, SIT91088, and SIT1580 were reported for the first time in Ethiopia. The family with the highest frequency identified was M. tuberculosis family T1, followed by family 33. Most of the strains belonged to Euro-American (61.4%) and Indo-Oceanic (36.3%) lineages.

CONCLUSIONS

The present study shows the importance of M. tuberculosis as a major cause of EPTB in the study area. Moreover, the majority of isolates of M. tuberculosis were found in clusters, suggesting the possibility of the existence of recent transmission. This warrants strengthening of the control programs for EPTB in the study area.

Detection of microorganisms in granulomas that have been formalin-fixed: review of the literature regarding use of molecular methods

Granuloma is an organized aggregate of immune cells that under the microscope appear as epithelioid macrophages. A granuloma can only be diagnosed when a pathologist observes this type of inflammation under the microscope. If a foreign body or a parasite is not observed inside the granuloma, stains for acid-fast bacilli and fungi are ordered since mycobacteria and fungi are frequently the cause of this type of inflammation. It is calculated that 12 to 36% of granulomas do not have a specific etiology and many have wondered if with new molecular methods we could reduce this number. This paper will summarize the frequently known causes of granulomas and will present the recent literature regarding the use of molecular techniques on tissue specimens and how these have helped in defining causative agents. We will also briefly describe new research regarding formation and function of granulomas and how this impacts our ability to find an etiologic agent.

Diagnosis of extrapulmonary tuberculosis by PCR

During the last two decades, the resurgence of tuberculosis (TB) has been documented in both developed and developing nations, and much of this increase in TB burden coincided with human immunodeficiency virus (HIV) epidemics. Since then, the disease pattern has changed with a higher incidence of extrapulmonary tuberculosis (EPTB) as well as disseminated TB. EPTB cases include TB lymphadenitis, pleural TB, TB meningitis, osteoarticular TB, genitourinary TB, abdominal TB, cutaneous TB, ocular TB, TB pericarditis and breast TB, although any organ can be involved. Diagnosis of EPTB can be baffling, compelling a high index of suspicion owing to paucibacillary load in the biological specimens. A negative smear for acid-fast bacilli, lack of granulomas on histopathology and failure to culture Mycobacterium tuberculosis do not exclude the diagnosis of EPTB. Novel diagnostic modalities such as nucleic acid amplification (NAA) can be useful in varied forms of EPTB. This review is primarily focused on the diagnosis of several clinical forms of EPTB by polymerase chain reaction (PCR) using different gene targets.

pncAMutations in the Specimens from Extrapulmonary Tuberculosis

Background

Pyrazinamide (PZA) is an effective antitubercular drug that becomes toxic to Mycobacterium tuberculosis when converted to pyrazinoic acid by pyrazinamidase (PZase), encoded by mycobacterial pncA. A strong association was noted between the loss of PZase activity and PZA resistance. The causative organisms in extrapulmonary tuberculosis are rarely cultured and isolated. To detect pncA mutations in specimens from extrapulmonary tuberculosis as confirmative diagnosis of mycobacterial infection and alternative susceptibility test to PZA.

Methods

Specimens were collected from clinically proven extrapulmonary tuberculosis. pncA was sequenced and compared with wild-type pncA.

Results

pncA from 30 specimens from 23 donors were successfully amplified (56.6% in specimens, 59% in donors). Six mutations in pncA were detected (20.0% in amplified specimens, 26.1% in specimen donors) at nucleotide positions of 169, 248 and 419. The mutation at position 169 results in substitution of aspartic acid for histidine, a possible allelic variation of M. bovis that have intrinsic PZA resistance. The mutation at position 248 changes proline into arginine and that at position 419, arginine into histidine.

Conclusion

DNA-based diagnosis using pncA may be simultaneously useful for the early diagnosis of mycobacterial infection and the rapid susceptibility to PZA in extrapulmonary tuberculosis. A potential implication of pncA allelic variation at 169 might be suggested as a rapid diagnostic test for M. bovis infection or Bacille Calmette-Guérin (BCG) reactivation.

Detection and identification of Mycobacterium tuberculosis and Mycobacterium bovis from clinical species using DNA microarrays

The objectives of the current study were to evaluate the use of DNA microarray for the rapid and direct detection of Mycobacterium tuberculosis and Mycobacterium bovis in bovine milk, blood, and pharyngeal swab samples, and to compare the use of DNA microarrays with current molecular detection techniques. The present study describes a microarray assay based on mtp40 and pncA gene sequences, which can be used to detect M. tuberculosis and M. bovis species. Each probe was spotted onto a silylated glass slide with an arrayer and used for hybridization with fluorescently labeled DNA derived from amplified DNA samples. The detection limit for mycobacterial DNA using this DNA microarray method was 50 fg (5 tubercle bacilli). Mycobacterium tuberculosis and/or M. bovis was detected in 7.1% (24/336) of the cattle specimens using the DNA microarray compared to 6.0% (20/336) using culture methods. Mixed infections were detected in 3 animals using the DNA microarray method, whereas the mixed infections were detected in 2 animals using either culture or polymerase chain reaction methods. The use of ancillary in vitro tests alongside the DNA microarray enhanced the detection of cattle infected with M. tuberculosis and/or M. bovis and reduced the number of false-positive animals that would be culled. More species may be easily added to this system, and supplementary probes can be added to increase the simultaneous detection power.

Extra pulmonary tuberculosis: a diagnostic dilemma

Tuberculosis remains a major public health problem globally, with India being one of the high burden countries. The common causative agent is Mycobacterium tuberculosis but in developing countries M. bovis is reported as a potential human pathogen. Almost 20% of all reported cases of tuberculosis are of extra pulmonary form of disease. Diagnosis of extra pulmonary tuberculosis (EPTB) is not always possible with conventional methods, due to the long time required and the paucibacillary nature of samples; hence the need of rapid molecular methods. A prospective study was conducted on 300 patients of EPTB over a period of 5 years. These patients were suspected cases of tubercular meningitis, tubercular ascites and tubercular lymphadenitis. Samples analyzed were cerebrospinal fluid, ascitic fluid and lymph node fine needle aspirate. A two step PCR targeting hup B gene was used. Clinical response to anti tubercular therapy (ATT) was taken as positive (gold standard). PCR for hup B gene was positive in 147 samples out of 155 ATT responders. Of these 85.71% were infected with M. tuberculosis, 9.52% with M. bovis alone and 4.76% showed co infection with both M.tb and M. bovis. The sensitivity and specificity of PCR was 90.32 and 94.48% respectively.

Knowledge of cervical tuberculosis lymphadenitis and its treatment in pastoral communities of the Afar region, Ethiopia

Background

Infection with Mycobacterium bovis (Mb) predominantly causes cervical TB lymphadenitis (TBL). Raw milk is considered the main source of Mb infection and raw milk is a major food source for Afar pastoralists. The aim of this study was to assess Afar pastoralists' knowledge concerning cervical TBL and its treatment.

Methods

A community-based cross-sectional survey involving 818 interviewees was conducted in two districts of the Afar Region, Ethiopia. In addition, two focus group discussions (FGDs) were conducted in each of the study areas, one with men and the other with women.

Results

Of the 818 interviewees [357 (43.6%) females and 461 (56.4%) males], 742 (90.7%) reported that they had knowledge of cervical TBL, mentioning that swelling(s) on the neck resulting in a lesion and scar are common symptoms. However, only 11 (1.5%) individuals mentioned that bacteria or germs are the causative agents of TBL. Three interviewees and a male discussant mentioned drinking raw milk as the cause of TBL. A considerable proportion (34.2%) of the interviewees and almost all the discussants suggested herbal medicine as an effective treatment. Male study participants were 1.82 times more likely to have overall knowledge of TBL than female study participants (adjusted OR, 1.82; 95% CI, 1.32 to 2.51, p < 0.001).

Conclusion

The pastoral community members in the study areas had little biomedical knowledge of the cause, the source of infection and the transmission route of cervical TBL. Furthermore, most community members believed that herbal medicines are the most effective treatment for TBL. Therefore, TB control programs in the Afar Region require the incorporation of public health education introducing current biomedical knowledge of the disease. In addition, further studies are important to elucidate which medicinal plants are used by Afar pastoralists to treat TBL.

M. tuberculosis in Lymph Node Biopsy Paraffin-Embedded Sections

Background. Tuberculosis lymphadenitis is one of the most common forms of all extrapulmonary tuberculosis. Objective. To evaluate the magnitude of M. tuberculosis from lymph node biopsy paraffin-embedded sections among suspected patients visiting the Jimma University Specialized Hospital. Method. A cross-sectional study design of histological examination among lymph node biopsy paraffin-embedded sections by Ziehl-Neelsen and hematoxylin/eosin staining technique was conducted from December, 2009, to October, 2010, at the Department of Medical Laboratory Science and Pathology. Result. Histopathological examination of the specimens by hematoxylin and eosin staining technique revealed the presence of granulomas. But for the caseation and necrosis they were present in 85% cases of nodal tissue biopsies. From those, 56.7% were from females. The presence of acid-fast bacilli was microscopically confirmed by ZN staining in 37 (61.7%) of the nodal tissue biopsies. Conclusion and Recommendation. Tuberculosis lymphadenitis is significantly more common in females. Hence, attention should be given for control and prevention of extrapulmonary tuberculosis.

First-time detection of mycobacterium species from goats in Ethiopia

Tuberculosis (TB) is an important zoonosis affecting a wide range of hosts. An abattoir study was conducted on 1,536 randomly selected male goats slaughtered at Modjo Modern Export Abattoir to determine the prevalence of tuberculosis in slaughtered goats. Carcasses and organs of all the study animals were first examined by routine meat inspection followed by detailed meat inspection. Samples from tuberculous lesions were cultured for mycobacterial isolation and identification. Histopathology was done on 31 samples with tuberculous lesions. Detailed meat inspection detected 65 (4.2%; 95% confidence interval (CI) = 3.3-5.4%) tuberculous lesions. From these, 20 (30.8%) samples were confirmed mycobacterium positive on culture, out of which 18 were Mycobacterium bovis and two were Mycobacterium tuberculosis. Routine meat inspection failed to detect tuberculous lesions in 23% of carcasses with TB lesions detected by detailed examination. However, no statistically significant difference was observed between both methods in detecting tuberculous lesions (Kappa = 0.87). Origin and age of the goats did not statistically affect the disease prevalence (P > 0.05). Histopathologic lesions were observed in 21 samples (68%; 95% CI = 50.1-81.4%) out of the 31 carcasses with gross tuberculous lesions examined by histopathology. Eighteen (58%) tuberculous samples positive for histopathology were also culture positive. The sensitivity and specificity of histopathology were 90% (95% CI = 76.9-100%) and 72.7% (95% CI = 46.4-99%), respectively, using culture as a reference test. To the best of our knowledge, this is the first report of caprine tuberculosis from Ethiopia. Further studies are required at the farm level to determine the prevalence of tuberculosis in the general goat population.

Diagnostic efficiency of abattoir meat inspection service in Ethiopia to detect carcasses infected with Mycobacterium bovis: implications for public health

Background

Bovine Tuberculosis (BTB) is a widespread and endemic disease of cattle in Ethiopia posing a significant threat to public health. Regular surveillance by skin test, bacteriology and molecular methods is not feasible due to lack of resource. Thus, routine abattoir (RA) inspection will continue to play a key role for national surveillance. We evaluated efficiency of RA inspection for diagnosis of Mycobacterium bovis infection and discussed its public health implications in light of a high risk of human exposure.

Methods

The study was conducted in five abattoirs: Addis Ababa, Adama, Hawassa, Yabello and Melge-Wondo abattoirs. The efficiency of routine abattoir (RA) inspection was validated in comparison to detailed abattoir (DA) inspection, followed by culture and microscopy (CM) and region of difference (RD) deletion analysis. Diagnostic accuracies (with corresponding measures of statistical uncertainty) were determined by computing test property statistics (sensitivity and specificity) and likelihood estimations using web-based SISA diagnostic statistics software. Post-test probability of detecting TB infected carcasses was estimated using nomograms. Agreement between RA and DA inspections was measured using kappa statistics. The study was conducted and reported in accordance with standards for reporting of diagnostic accuracy (STARD) requirements. Both routine and detailed meat inspection protocols were performed on a subpopulation of 3322 cattle selected randomly from among 78,269 cattle slaughtered during the study period. Three hundred thirty seven carcasses identified through detailed meat inspection protocols were subjected to culture and microscopy; of the 337, a subset of 105 specimens for culture and microscopy were subjected to further molecular testing.

Results

There was a substantial agreement between RA and DA inspections in Addis Ababa (Kappa = 0.7) and Melge-Wondo abattoirs (Kappa = 0.67). In Adama, Hawassa and Yabello abattoirs, the agreement was however poor (Kappa ≤ 0.2). RA inspection was able to detect only 117 of the total 3322 carcasses inspected (3.5%). The sensitivity (Sn) and specificity (Sp) of RA inspection were 28.2% (95/337) [95%CI: 23.4-33.0] and 99.3% (2963/2985) [95%CI: 99.0-99.6], respectively, when DA inspection was considered as reference test. When culture and microscopy (CM) was considered as reference test, the Sn and Sp of RA were 55.2% (58/105) [95%CI: 45.7-64.7] and 84.1% (195/232) [95%CI: 79.3-88.8]. RA inspection failed to detect 71.8% (242/337) and 44.8% (47/105) of TB infected carcasses as judged by DA inspection and CM, respectively. On the other hand, a much higher sensitivity of DA was obtained when CM and RD deletion analysis were considered as reference tests (96.3% (105/109) and 100.0% (24/24), respectively).

Conclusions

The study results indicate that meat inspection protocols currently utilized in abattoirs are insufficient to detect the majority of TB lesions at the gross level. DA inspection protocols were demonstrated to improve the detection level by approximately 3-fold. The failure of current inspection techniques to detect approximately 70% of carcasses presented with grossly-visible lesions of TB at the slaughter-plants indicates the magnitude of meat-borne zoonotic TB as an on-going risk to public health. Standardization of abattoir inspection protocols (in line with international sanitary requirements), enhanced training and proficiency testing of meat inspections, and raising public awareness are recommended as essential and cost-effective interventions to improve meat inspection service in Ethiopia, with subsequent protection of consumers' health.