Tuberculosis Complex Species Research Articles

TB or not TB? Definitive determination of species within the Mycobacterium tuberculosis complex in unprocessed sputum from adults with presumed multidrug-resistant tuberculosis.

ObjectivesDifferences among Mycobacterium tuberculosis complex (MTC) species may predict drug resistance or treatment success. Thus, we optimised and deployed the genotype MTBC assay (gMTBC) to identify MTC to the species level, and then performed comparative genotypic drug‐susceptibility testing to anti‐tuberculosis drugs from direct sputum of patients with presumed multidrug‐resistant tuberculosis (MDR‐TB) by the MTBDRplus/sl reference method.MethodsPatients with positive Xpert® MTB/RIF (Xpert) results were consented to provide early‐morning‐sputum for testing by the gMTBC and the reference MTBDRplus/sl. Chi‐square or Fisher’s exact test compared proportions. Modified Poisson regression modelled detection of MTC by gMTBC.ResultsAmong 73 patients, 53 (73%) were male and had a mean age of 43 (95% CI; 40–45) years. In total, 34 (47%), 36 (49%) and 38 (55%) had positive gMTBC, culture and MTBDR respectively. Forty patients (55%) had low quantity MTC by Xpert, including 31 (78%) with a negative culture. gMTBC was more likely to be positive in patients with chest cavity 4.18 (1.31–13.32, P = 0.016), high‐quantity MTC by Xpert 3.03 (1.35–6.82, P = 0.007) and sputum smear positivity 1.93 (1.19–3.14, P = 0.008). The accuracy of gMTBC in detecting MTC was 95% (95% CI; 86–98; κ = 0.89) compared to MTBDRplus/sl. All M. tuberculosis/canettii identified by gMTB were susceptible to fluoroquinolone and aminoglycosides/capreomycin.ConclusionsThe concordance between the gMTBC assay and MTBDRplus/sl in detecting MTC was high but lagged behind the yield of Xpert MTB/RIF. All M. tuberculosis/canettii were susceptible to fluoroquinolones, a core drug in MDR‐TB treatment regimens.

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 10years 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.

Whole Genome Sequence Analysis of Mycobacterium bovis Cattle Isolates, Algeria.

Mycobacterium bovis (M. bovis), a Mycobacterium tuberculosis complex species responsible for tuberculosis in cattle and zoonotic tuberculosis in humans, is present in Algeria. In Algeria however, the M. bovis population structure is unknown, limiting understanding of the sources and transmission of bovine tuberculosis. In this study, we identified the whole genome sequence (WGS) of 13 M. bovis strains isolated from animals exhibiting lesions compatible with tuberculosis, which were slaughtered and inspected in five slaughterhouses in Algeria. We found that six isolates were grouped together with reference clinical strains of M. bovis genotype-Unknown2. One isolate was related to M. bovis genotype-Unknown7, one isolate was related to M. bovis genotype-Unknown4, three isolates belonged to M. bovis genotype-Europe 2 and there was one new clone for two M. bovis isolates. Two isolates from Blida exhibited no pairwise differences in single nucleotide polymorphisms. None of these 13 isolates were closely related to four zoonotic M. bovis isolates previously characterized in Algeria. In Algeria, the epidemiology of bovine tuberculosis in cattle is partly driven by cross border movements of animals and animal products.

Accurate Identification of Closely Related Mycobacterium tuberculosis Complex Species by High Resolution Tandem Mass Spectrometry.

Rapid and accurate differentiation of Mycobacterium tuberculosis complex (MTBC) species from other mycobacterium is essential for appropriate therapeutic management, timely intervention for infection control and initiation of appropriate health care measures. However, routine clinical characterization methods for Mycobacterium tuberculosis (Mtb) species remain both, time consuming and labor intensive. In the present study, an innovative liquid Chromatography-Mass Spectrometry method for the identification of clinically most relevant Mycobacterium tuberculosis complex species is tested using a model set of mycobacterium strains. The methodology is based on protein profiling of Mycobacterium tuberculosis complex isolates, which are used as markers of differentiation. To test the resolving power, speed, and accuracy of the method, four ATCC type strains and 37 recent clinical isolates of closely related species were analyzed using this new approach. Using different deconvolution algorithms, we detected hundreds of individual protein masses, with a subpopulation of these functioning as species-specific markers. This assay identified 216, 260, 222, and 201 proteoforms for M. tuberculosis ATCC 27294™, M. microti ATCC 19422™, M. africanum ATCC 25420™, and M. bovis ATCC 19210™ respectively. All clinical strains were identified to the correct species with a mean of 95% accuracy. Our study successfully demonstrates applicability of this novel mass spectrometric approach to identify clinically relevant Mycobacterium tuberculosis complex species that are very closely related and difficult to differentiate with currently existing methods. Here, we present the first proof-of-principle study employing a fast mass spectrometry-based method to identify the clinically most prevalent species within the Mycobacterium tuberculosis species complex.

Application value of tissue tuberculosis antigen combined with Xpert MTB/RIF detection in differential diagnoses of intestinal tuberculosis and Crohn\u2019s disease

BackgroundThe purpose of this study was to examine the value of Xpert MTB/RIF assay and detection of additional Mycobacterium tuberculosis complex (MTBC) species antigens from intestinal tissue samples in differentiating intestinal tuberculosis (ITB) from Crohn’s disease (CD).MethodsSeveral clinical specimens of intestinal tissue obtained by either endoscopic biopsy or surgical excision were used for mycobacteriologic solid cultures,Xpert MTB/RIF assays, immunohistochemistry, and histological examinations. Four antigens (38KDa, ESAT-6, MPT64, and Ag85 complex) of MTBC in the intestinal tissue were detected by immunohistochemical analysis.ResultsThe study included 42 patients with ITB and 46 with CD. Perianal lesions and longitudinal ulcers were more common in patients with CD, while caseating granuloma and annular ulcers were more common in patients with ITB. The positive rate of MTBC detected by Xpert MTB/RIF in intestinal tissues of patients with ITB was 33.33%, which was significantly higher than that in patients with CD and that detected using acid-fast staining smears. It was also higher than that detected by tissue MTBC culture, but the difference was not statistically significant. The positive MPT64 expression rate in patients with ITB was 40.48%, which was significantly higher than that observed in patients with CD. The sensitivity of parallelly combined detection of tuberculosis protein MPT64 and Xpert MTB/RIF in diagnosing ITB was 50.0%.ConclusionsThe detection of Xpert MTB/RIF in intestinal tissue is a rapid and useful method for establishing an early diagnosis of ITB. The detection of MTBC using Xpert MTB/RIF and MPT64 antigen in intestinal tissues has a definitive value in the differential diagnosis ofITB and CD. The combination of these two methods can improve the detection sensitivity.

Histopathological and microbiological study of porcine lymphadenitis: contributions to diagnosis and control of the disease

Tuberculosis like lesions (TBL) in free-range pigs are characterised by presenting a marked heterogeneity in pathology and microbiology features, with a notorious role of Mycobacterium tuberculosis complex (MTC), Trueperella pyogenes and different Streptococcus species. However, the capacity of these microorganism to spread to different organic cavities leading to a generalised disease is unknown. Therefore, this study evaluated the organic distribution of these agents in free-range pig carcasses whole condemned due to generalised TBL.A total of 37 totally condemned animals were analysed, and samples of lymph nodes and organs were obtained (n = 262) and subjected to histopathological and microbiological examination. In addition, T. pyogenes and streptococci species were further characterised by PFGE analysis. Two different patterns were evidenced with lack or occasional lesions in superficial inguinal (SILN) and popliteal (PLN) lymph nodes and advanced lesions in submandibular (SLN) (35/36) and gastrohepatic (GHLN) (33/35) lymph nodes (stages III and IV). Early stage granulomas (stage I and II) prevailed in lungs (16/20), liver (14/31) and spleen (7/18). The microbiological analysis revealed that MTC, detected by qPCR, was present in 31 out of 37 animals and 90 (90/262) samples. In 26 out of the 31 pigs, MTC was detected from two or more organs. SLN (24/31) and GHLN (19/31) were the MTC+ organs most frequently detected, with 29 out of 31 MTC+ pigs detected as positive in one or both samples, which points out that both lymph nodes must be included in the sampling of surveillance programs. Other pathogens, such as T. pyogenes and Streptococcus spp., were also involved in generalised lymphadenitis, being frequently isolated from SLN and other organs, such as liver (T. pyogenes), tonsils or lung (Streptococcus spp.). A wide genetic diversity among streptococci was observed, showing the ubiquitous character of these pathogens, however, the isolation of a single clone of T. pyogenes from different organic locations from animals with generalised TBL was a common finding of this study, highlighting that the role of this pathogen in porcine lymphadenitis may be underestimated. These results should be considered in future studies on the pathogenesis and control of porcine lymphadenitis.

Role of the PE/PPE Family in Host-Pathogen Interactions and Prospects for Anti-Tuberculosis Vaccine and Diagnostic Tool Design.

The pe/ppe genes are found in pathogenic, slow-growing Mycobacterium tuberculosis and other M. tuberculosis complex (MTBC) species. These genes are considered key factors in host-pathogen interactions. Although the function of most PE/PPE family proteins remains unclear, accumulating evidence suggests that this family is involved in M. tuberculosis infection. Here, we review the role of PE/PPE proteins, which are believed to be linked to the ESX system function. Further, we highlight the reported functions of PE/PPE proteins, including their roles in host cell interaction, immune response regulation, and cell fate determination during complex host-pathogen processes. Finally, we propose future directions for PE/PPE protein research and consider how the current knowledge might be applied to design more specific diagnostics and effective vaccines for global tuberculosis control.

Utility of xpert® MTB/RIF ultra assay in the rapid diagnosis of bovine tuberculosis in wildlife and livestock animals from South Africa

Members of the Mycobacterium tuberculosis complex (MTBC) bacteria, mainly Mycobacterium bovis (M. bovis), cause bovine tuberculosis (bTB) in livestock and wildlife animals. Confirmation of the disease is through culture and verification of the causative agent by molecular tests. In this study, we assessed the utility of the Xpert ® MTB/RIF Ultra assay, an automated molecular test originally designed to improve the detection of tuberculosis (TB) and rifampicin resistance in clinical sputum samples of human origin, by conducting a comparative evaluation with a culture based method routinely used at the Onderstepoort Veterinary Research (OVR). A total of 167 samples (tissue, n = 165; pus, n = 1; abscess, n = 1) from different wildlife and livestock animals (from 65 individual animals) were analyzed. Mycobacterium tuberculosis complex species was isolated in 63 (37.72 %) of the 167 samples, and was detected in 79 (47.3 %) of the samples by Xpert ® MTB/RIF Ultra assay. Based on the standard culture test, the diagnostic sensitivity and specificity of the Xpert ® MTB/RIF Ultra assay was found to be 95.24 % and 82 % respectively. All animals that were confirmed bTB positive by culture method were also found to be positive with the Xpert ® MTB/RIF Ultra assay in at least one sample (indicating a 100 % sensitivity of the method at the animal level). Non-tuberculous mycobacteria were isolated in 9 (3.4 %) of the samples analysed and none were detected by Xpert ® MTB/RIF Ultra assay, highlighting that this molecular test is highly specific. Xpert ® MTB/RIF Ultra assay was found to have great potential for the rapid diagnosis of the bTB in animals, hence allowing early intervention by regulatory authorities.

Phylogenomic Perspective on a Unique Mycobacterium bovis Clade Dominating Bovine Tuberculosis Infections among Cattle and Buffalos in Northern Brazil

Lack of routine surveillance in countries endemic for bovine tuberculosis (TB) and limited laboratory support contributes to the inability to differentiate the Mycobacterium tuberculosis Complex species, leading to an underestimated burden of the disease. Here, Whole-Genome Sequencing of Mycobacterium bovis isolated from tissues with TB-like lesions obtained from cattle and buffalos at Marajó Island, Brazil, demonstrates that recent transmission of M. bovis is ongoing at distinct sites. Moreover, the M. bovis epidemiology in this setting is herein found to be dominated by an endemic and unique clade composed of strains evolved from a common ancestor that are now genetically differentiated from other M. bovis clades. Additionally, envisioning a rapid strain differentiation and tracing across multiple settings, 28 globally validated strain-specific SNPs were identified, three of which considered as robust markers for the M. bovis Marajó strain. In conclusion, this study contributes with data regarding the identification of a novel M. bovis phylogenetic clade responsible for ongoing transmission events in both cattle and buffalo species in Brazil, provides a framework to investigate the dissemination of this highly prevalent strain and, holds the potential to inform TB control strategies that may help to prevent the spread of bovine and zoonotic TB.

Identification of nontuberculous mycobacteria species by multiplex real-time PCR with high-resolution melting.

INTRODUCTION: Nontuberculous mycobacteria (NTM) species, as human pathogens, are increasing in the world, as is the difficulty of accurately identifying them. Differential diagnosis, especially between the M. tuberculosis complex and NTM species, and the characterization of NTM species is important. This study aimed to evaluate the performance of a molecular system based on multiplex real-time PCR with high-resolution melting (HRM) for the identification and differentiation of NTM species of clinical importance of an endemic area for tuberculosis in northeastern Brazil. METHODS: The technical protocol of the molecular system was based on multiplex real-time PCR-HRM, and evaluated the sensitivity and specificity of the detection of NTM species in mycobacterial clinical isolates from the studied region. The gold standard method was specific gene sequencing. RESULTS: The sensitivity and specificity of multiplex real-time PCR-HRM modified for differentiation between NTM and M. tuberculosis were 90% and 100%, respectively. The PCR-HRM sensitivities for the characterization of NTM species (M. kansasii, M. abscesses, M. avium, and M. fortuitum) were 94.59%, 80%, 57.14%, and 54%, respectively. CONCLUSIONS The multiplex real-time PCR-HRM modified assay has the potential to rapidly and efficiently identify nontuberculous mycobacteria of clinical importance, which is crucial for immediate implementation of the appropriate therapy and thus avoiding complications and sequelae in patients.

The role of IS6110 in micro- and macroevolution of Mycobacterium tuberculosis lineage 2

The insertion sequence 6110 (IS6110) is the most studied transposable element in the Mycobacterium tuberculosis complex species. The element plays a significant role in genome plasticity of this important human pathogen, but still many causes and consequences of its transposition have not been fully studied. Here, we analyzed insertion sites for 902 Mycobacterium tuberculosis lineage 2 strains using whole-genome sequencing data. In total, 17,972 insertions were found, corresponding to 827 independent positions in the genome of the reference strain H37Rv. To trace the history of IS6110 expansion since proto-Beijing strains up to modern sublineages, we looked at the distribution of IS6110 across the genome-wide SNP-based phylogenetic tree. This analysis demonstrated a stepwise transposition of IS6110 that occurs by «copy-and-paste» mechanism. Additionally, we detected evolutionary-scale and sublineage-specific integration sites, which can be used for typing and for understanding the reasons for the success of the lineage. A significant part of such insertions affected the genes that are essential for the pathogen. Finally, we identified and confirmed deletions that occurred between differently oriented elements, which is uncommon for this family of insertion elements and appears to be another mechanism of genome variability.

The Importance of investigating Mycobacterium bovis in clinical samples of human origin

Introduction: Tuberculosis is an infectious disease that still represents a major public health problem worldwide. It is one of the main causes of mortality in people with HIV. Objective: To identify the presence of M. bovis as an etiological agent of human tuberculosis in sputum smear positive samples using the test Genotype MTBC™. Materials and methods: We conducted a descriptive study, 88 sputum samples were submitted to the Grupo de Micobacterias of the Instituto Nacional de Salud between January and November, 2015. We used the conventional microbiological analysis and the molecular test Genotype MTBC™ to identify the M. tuberculosis complex species. Results: Sixty two (70.5%) were males; the most affected groups were those between 24 and 34 years old, those residing in the municipal seats and those affiliated to the subsidized health plans. In 50.0% (44) of the samples with a result in the species identification test, we detected M. tuberculosis. Conclusion: The highest burden of the disease was recorded among the male population in productive ages. The identification test for species of the complex showed all were M. tuberculosis. However, it is not possible to discard the presence of M. bovis in humans in Colombia. The differential identification of species should be done in risk groups and in areas where the circulation of this mycobacterium in cattle is known.

Mycobacterioses identified in the National Reference Laboratory of Colombia from 2012 to 2016

Introduction: In recent years, there has been an increase in the prevalence of mycobacterioses caused by non-tuberculous mycobacteria, which are considered as emerging pathogens. Their presence depends on several factors such as the clinical history, the health status of the affected person, and the presence of these microorganisms in the water, the soil, and the animals, among others. Objective: To describe the mycobacteria and the etiological agent identified in isolates received at the Laboratorio Nacional de Referencia de Micobacterias of the Instituto Nacional de Salud between 2012 and 2016. Materials and methods: We conducted a retrospective analysis of samples from 273 patients with mycobacterioses. We analyzed the following variables: mycobacteriosis type, etiological agent, and associated predisposing factors. Results: 57.1% of the cases presented pulmonary mycobacteriosis; 26%, cutaneous; 10.6%, disseminated, and 2.6%, lymphatic. We found the Mycobacterium avium complex more frequently in pulmonary mycobacteriosis, while M. abscessus was more frequent in the extrapulmonary types of the disease. Patients with pulmonary mycobacteriosis had a history of tuberculosis more frequently than those with extrapulmonary forms. Conclusion: These findings highlight the importance of the differential diagnosis between M. tuberculosis complex species and non-tuberculous mycobacteria since the latter are genetically resistant to conventional antituberculosis drugs.

Recurrent bilateral Mycobacterium bovis necrotizing epididymitis: a case report

BackgroundMycobacterium bovis causing tuberculosis in animals is responsible for zoonotic tuberculosis in patients. Veterinary control measures and milk pasteurization has led to a significant decrease in human cases of M. bovis infections in developed countries.Case presentationWe diagnosed recurrent M. bovis epididymitis in a 63-year old Caucasian man without any signs of pulmonary or disseminated disease. Relevant epidemiological expositions included camel milk drinking during prolonged travels in Niger, prior to initial clinical manifestations. The diagnosis was firmly established by mass spectrometry and DNA sequencing on epididymis surgical biopsy specimens. We detail therapeutic management which included surgical epididymectomy and hydrocele repair.ConclusionAs for other M. tuberculosis complex species, the genitourinary tract represents a frequent site of secondary dissemination and latency for M. bovis. Isolated epididymis infection is a newly documented manifestation of M. bovis disease.

Nontuberculosis mycobacteria are the major causes of tuberculosis like lesions in cattle slaughtered at Bahir Dar Abattoir, northwestern Ethiopia

BackgroundThe main cause of bovine tuberculosis (bTB) is believed to be Mycobacterium bovis (M. bovis). Nontuberculosis mycobacteria (NTM) are neglected but opportunistic pathogens and obstacles for bTB diagnosis. This study aimed to isolate and characterize the mycobacteria organisms involved in causing TB-like lesions in cattle in northwestern Ethiopia.ResultsA total of 2846 carcasses of cattle were inspected for TB lesions. Ninety six tissues (including lymph nodes such as submandibular, retropharyngeal, tonsilar, mediatinal, bronchial and mesenteric, and organs such as lung, liver and kidney) with suspicious TB lesion(s) were collected and cultured on Lowenstein-Jensen medium. Twenty one showed culture growth, of which only 17 were identified containing acid fast bacilli (AFB) by Ziehl–Neelsen staining. Among the 17 AFB isolates 15 generated a polymerase chain reaction product of 1030 bp by gel electrophoresis based on the 16S ribosomal RNA gene amplification. No M. tuberculosis complex species were isolated. Further characterization by Genotype Mycobacterium CM assay showed 6 isolates identified as M. peregrinum. Eight isolates represented by mixed species, which includes M. fortuitum-peregrinum (3 isolates), M. gordonae-peregrinum (3 isolates) and M. fortuitum-gordonae-peregrinum (2 isolates). One NTM could not be interpreted.ConclusionA significant number of NTM species were isolated from TB-like lesions of grazing cattle slaughtered at Bahir Dar Abattoir. Such finding could suggest the role of NTM in causing lesions in cattle. Further investigations are recommended on the pathogenesis of the reported NTM species in cattle, and if they have public health significance.

Extended spectrum of antibiotic susceptibility for tuberculosis, Djibouti

In the Horn of Africa, there is a high prevalence of tuberculosis that is reported to be partly driven by multidrug-resistant (MDR) Mycobacterium tuberculosis strictu sensu strains. We conducted a prospective study to investigate M. tuberculosis complex species causing tuberculosis in Djibouti, and their in vitro susceptibility to standard anti-tuberculous antibiotics in addition to clofazimine, minocycline, chloramphenicol and sulfadiazine. Among the 118 mycobacteria isolates from 118 successive patients with suspected pulmonary tuberculosis, 111 strains of M. tuberculosis, five Mycobacterium canettii, one ‘Mycobacterium simulans’ and one Mycobacterium kansasii were identified. Drug-susceptibility tests performed on the first 78 isolates yielded nine MDR M. tuberculosis isolates. All isolates were fully susceptible to clofazimine, minocycline and chloramphenicol, and 75 of 78 isolates were susceptible to sulfadiazine. In the Horn of Africa, patients with confirmed pulmonary tuberculosis caused by an in vitro susceptible strain may benefit from anti-leprosy drugs, sulfamides and phenicol antibiotics.

Rapid and specific detection of Mycobacterium tuberculosis directly from sputum specimens using IS6110 and pncA through multiplex-PCR

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis complex, is the second leading cause of death. One third of the world’s population is infected with TB. Every day more than 23000 people develop active TB and nearly 5000 die. Approximately 20-50% of patients with TB are smear negative, accounting for as much as 17% of TB transmission, posing an important public health hazard. In the objective of improved TB diagnosis and rapid detection of M. tuberculosis complex species particularly from paucibacillary sputum specimens, the sensitivity of Polymerase Chain Reaction (PCR) using IS6110 and pncA as genetic targets was compared with the conventional fluorescent microscopy. The study also aimed to check the sensitivity of two different genetic markers IS6110 and pncA for the detection of M. tuberculosis. Sputum specimens were collected from TB suspected subjects (N= 200; males=108; females=92; mean age=47±18.4) attending outpatient department at Fatima Jinnah General and Chest Hospital, Quetta. All the samples were decontaminated using N-acetyl-L-cysteine (NALC)-NaOH method and were subjected to auramine-O fluorescent microscopy and multiplex PCR using TB1 and TB2 primers specific for M. tuberculosis complex and pncATB-1.2 and pncAMT-2 primers specific to M. tuberculosis. Out of 200 specimens, M. tuberculosis around 15 (7.5%) was detected by fluorescent microscopy and 33 (16.5%) were detected through PCR, respectively. Whereas 18 smear negative specimens were found to be positive by PCR. Statistically significant difference between fluorescent microscopy and PCR was observed (p 0.05). Similarly, age was not found to be associated (p>0.05) with the increased risk of TB, however, the disease incidence was more prevalent (20.89%) in patients aged 41–60 years. Multiplex PCR showed increased sensitivity as compared to fluorescent microscopy for TB diagnosis and will bea useful tool in detecting smears negative TB. Further, it can also be concluded that both genetic markers IS6110 and pncA showed similar sensitivity in the detection of M. tuberculosis. Keywords: Quetta; Tuberculosis; Paucibacillary; Diagnosis; Genetic markers http://dx.doi.org/10.19045/bspab.2017.60052

Identifying and characterising PPE7 (Rv0354c) high activity binding peptides and their role in inhibiting cell invasion.

This study was aimed at characterising the PPE7 protein from the PE/PPE protein family. The presence and transcription of the rv0354c gene in the Mycobacterium tuberculosis complex was determined and the subcellular localisation of the PPE7 protein on mycobacterial membrane was confirmed by immunoelectron microscope. Two peptides were identified as having high binding activity (HABPs) and were tested in vitro regarding the invasion of Mycobacterium tuberculosis H37Rv. HABP 39224 inhibited invasion in A549 epithelial cells and U937 macrophages by more than 50%, whilst HABP 39225 inhibited invasion by 40% in U937 cells. HABP 39224, located in the protein's C-terminal region, has a completely conserved amino acid sequence in M. tuberculosis complex species and could be selected as a base peptide when designing a subunit-based, anti-tuberculosis vaccine.

Molecular typing of mycobacteria isolated from tuberculous lymphadenitis cases in Addis Ababa, Ethiopia.

In Ethiopia, one of the world's 22 high tuberculosis (TB) burden countries, one third of the tuberculosis (TB) cases are attributed to tuberculosis lymphadenitis (TBLN). However, information on the molecular type of the mycobacterial species and strains that cause TBLN in the country is scarce. To identify the species and strains of mycobacteria that cause TBLN in Ethiopia. A cross-sectional study was conducted among 206 presumed TBLN cases to characterise positive culture isolates. Mycobacterium tuberculosis complex species and strains were identified using region of difference 9 deletion and SITVIT WEB, respectively. Of the 206 fine-needle aspirate samples collected, 74 (36%) were culture-positive: 73 (98.6%) of the isolates were M. tuberculosis, and the remaining 1.4% were M. bovis. Further characterisation of the 73 M. tuberculosis isolates led to 26 distinct spoligotype international types (SITs) and 13 newly identified patterns. The most prevalent strains were SIT149, SIT53, SIT26 and SIT37 of sublineages T3-ETH, T1, CASI-DELHI and T3, respectively; these accounted for 52.6% of the total number of strains. TBLN was mainly caused by M. tuberculosis and highly clustered strains SIT149, SIT53, SIT26 and SIT37 of sublineages T3-ETH, T1, CASI-DELHI and T3, respectively.

Molecular Confirmation of Conserved Nature of Genes Encoding MPB53 and MPB63 Immune Dominant Proteins in Indian Strain of Mycobacterium bovis

The genes encoding MPB53 and MPB63 immuno dominant proteins of Mycobacterium bovis field strain 3/86-RV were amplified by polymerase chain reaction (PCR). The recombinant plasmids were constructed via inserting the mpb53 and mpb63 genes into the pET vector (named pET28b-mpb53 and pET28b-mpb63). The nucleotide sequences of the insert PCR products were determined by vector specific primer. Both genes contained an open reading frame of 402 and 390 base pairs for mpb53 and mpb63, respectively. The sequenced genes and its deduced amino acid sequences were compared with the published sequences of reference M. tuberculosis complex strains. The sequences of the mpb53 and mpb63 genes share more than 99 % nucleotide homology and deduced protein sequence homology pointing towards conserved molecular nature of these immunodominant proteins among M. tuberculosis complex species.