Direct detection of Mycobacterium tuberculosis with nitrate reductase assay and microscopic observation drug susceptibility

The global increase in tuberculosis drug resistant which is a threat to its control, require low cost method of diagnosis and detection. Available conventional and molecular methods consume time, and are expensive for countries with high disease burden. Nitrate Reductase Assay (NRA) and Microscopic Observation Drug Susceptibility (MODS) performance to directly detect tuberculosis resistance to four drugs was evaluated. The NRA (liquid and solid) and MODS performance of smear-positive sputum samples were evaluated; Sensitivities and specificities were compared with Proportion Method (PM). Sensitivity and specificity of liquid NRA (LNRA) were 90% and 98% (rifampicin), 81.8% and 100% (isoniazid), 88.9% and 98.1% (streptomycin), and 57.1% and 94.4% (ethambuthol). Also, the sensitivity and specificity for solid NRA (SNRA) were 69.2% and 98.3% (rifampicin); 100% and 100% (isoniazid); 88.9% and 95.2% (streptomycin); 70% and 80.6% (ethambuthol). Moreover, For MODS, rifampicin and isoniazid sensitivity and specificity was 100%, it was 100% and 98.1% for streptomycin, and 71.4% and 98.2% for ethambuthol. At day 14, the results available for LNRA, SNRA and MODS were 93%, 68.5% and 100% respectively. The agreement between LNRA and PM was 97% (RIF, INH and SM) and 90% (EMB). For SNRA, it was 93% (RIF), 100% (INH), 94% (SM) and 89% (EMB). While for MODS, it was 100% (RIF and INH), 98% (SM) and 95% (EMB). Direct NRA and MODS are sensitive, reliable and fast for antituberculosis drug susceptibility; they have potential to effectively and reliably detect drug resistant tuberculosis in the low resource countries. DOI: http://dx.doi.org/10.5281/zenodo.429588

Patterns of drug resistance in Mycobacterium tuberculosis from tuberculosis patients in Ibadan Nigeria

The success of the global tuberculosis (TB) control program has been threatened with drug resistant strains emergence; especially the Multidrug Resistant Tuberculosis (MDR-TB). Despite that Nigeria is one of the countries with high tuberculosis burden, little is known on the magnitude of MDR-TB in the country. This study was to determine drug resistant patterns of Mycobacterium tuberculosis isolated from patients that attended Directly Observed Treatment Short-course (DOTS) centres in Ibadan, Nigeria. Sputum samples collected from confirmed TB patients were processed using the N-acetyl L-cysteine-sodium hydroxide decontamination method. Direct drug susceptibility test was carried out against rifampicin, isoniazid, ethambuthol and streptomycin. Out of the 319 samples collected, 149 (46.7%) were culture positive and susceptibility test was completed for 101 (67.8%) isolates, out of which any resistance and mono-resistance to rifampicin was 23.8% and 8.9% respectively. In all 11.9% MDR-TB was observed comprising 30.8% (acquired), and 8.3% (primary) while, 3.96% showed resistance to all tested drugs. The patterns of MDR-TB in this study indicates that active case findings as well as expansion of drug susceptibility testing is required to effectively control TB, drug resistant strains and to forestall the transmission and spread of the drug-resistant TB in the society. DOI: http://dx.doi.org/10.5281/zenodo.428850

Isolation of Mycobacterium tuberculosis from livestock workers and implications for zooanthroponotic transmission in Ibadan, South-western Nigeria

Introduction: Tuberculosis (TB) remains a public health problem in sub-Saharan Africa coupled with dearth of information about the disease among livestock workers at risk of infection. We determined the prevalence of pulmonary TB infection and risk factors associated with its occurrence among livestock workers in south-western Nigeria. Methods:  A cross-sectional study was conducted using active case-finding among livestock workers with sub-clinical pulmonary TB between August, 2014 and March, 2015. Sputum samples were cultured and subjected to a two-step multiplex-PCR technique based on genus-typing and genomic regions-of-difference. Interviewer-administered questionnaire was utilized in assessing worker’s TB related knowledge, attitude and practices. Data were analysed using STATA 12.Results: Overall, 206 livestock workers (traders =136; butchers = 70) were screened; 5.1% (7/136) of the traders and 7.1% (5/70) of the butchers had positive mycobacterial cultures. Molecular techniques identified one Mycobacterium tuberculosis with six non-tuberculous mycobacteria (NTM) from the traders and four M. tuberculosis with one NTM from the butchers.Participants within the age range of 50 years and above were at higher risk of being infected with TB (OR=7.7; 95%CI:1.7–35.6).Conclusion: We confirmed M. tuberculosis as the cause of pulmonary TB among the livestock workers, with implications for zooanthroponotic transmission of the disease along the human-animal ecosystem interface in Nigeria

Diagnostic performance of GeneXpert and Ziehl-Neelson microscopy in the detection of tuberculosis in Benue State, Nigeria

Background: Accurate and timely diagnosis of tuberculosis (TB) is key to effective treatment and management. This study was designed to compare the diagnostic performance of GeneXpert and Ziehl-Neelson (ZN) microscopy test using culture as the reference.Methods: Cross-sectional study was conducted in a tertiary hospital to compare the performance of GeneXpert and ZN test among HIV and non-HIV patients. Sputum samples were collected from 261 suspected TB patients and analyzed in the laboratory using GeneXpert, ZN test and culture. Statistical analysis included calculation of sensitivity, specificity, positive predictive value and negative predictive value. X2 was used to compare the outcome of diagnostic test and demographic variables. p-value < 0.05 was considered significant.Results: Comparison of TB prevalence among urban versus rural areas using the three diagnostic tests are: ZN test: 32 (12.3%) vs 16 (6.1%; X2 7.63, P = 0.007); GeneXpert: 63 (16.1%) vs 20 (7.7%, X2 9.01, P = 0.003) and culture: 22 (8.4%) vs 10 (3.8% X2 4.44, P = 0.05). Also, prevalence of TB was significantly (P < 0.05) higher among HIV negative 25 (9.6%) than HIV positive 23 (8.8%) patients. The overall prevalence of rifampicin resistance was 12 (4.60%). Out of 261 sputum samples examined for TB, 48 (18.38%) tested positive by ZN test, 62 (23.76%) by GeneXpert and 32 (12.26%) by culture. Two out of 32 samples that tested positive by culture were negative by GeneXpert. GeneXpert had higher sensitivity (93.75%) than ZN test (50.00%). However, they had equal specificity (86.03%). The sensitivity and specificity of ZN and GeneXpert among HIV patients was 58.33% (95% CI = 29.66–84.83) and 79.31% (95% CI; 69.24–87.26) and 91.67% (95% CI 61.51–99.79) and 80.67 (95% CI; 70.58–88.17) while among HIV negative patients; ZN test and GeneXpert assay had 45.00% (23.05–68.45) and 90.14% (84.04–94.50) and 95.00% (75.13–99.87) and 89.44% (83.13–93.96), respectively.Conclusion: GeneXpert demonstrated higher level of performance than ZN microscopy. We recommend the use of GeneXpert for diagnosis of TB in Benue State and Nigeria in general for effective treatment and management of tuberculosis.Keywords: Diagnostic performance, GeneXpert MTB/Rif, Ziehl-Neelson, Tuberculosis, HI

Sero-epidemiological survey and risk factors associated with brucellosis in dogs in south-western Nigeria

Introduction: In Nigeria, there is limited information on brucellosis particularly in dogs, despite its public health implications. We undertook a sero-epidemiological survey of brucellosis in dogs to determine the prevalence of the disease and associated risk factors for its occurrence in Nigeria. Methods: A cross-sectional study was conducted to screen dogs in south-western Nigeria for antibodies to Brucella sp using the rapid slide agglutination test (RSA) and Rose Bengal test (RBT), with positive samples confirmed respectively by serum agglutination test (SAT) and competitive enzyme linked immunosorbent assay (cELISA). Data were analyzed with STATA-12. Results: From the 739 dog sera tested, 81 (10.96%) were positive by RSA and 94 (12.72%) by RBT; these were corroborated with SAT (4/81; 4.94%) and cELISA (1/94; 1.06%), respectively. Logistic regression identified location (OR=0.04; 95% CI: 0.02-0.09), breed (OR=1.71; 95% CI: 1.34-2.19), age (OR=0.10; 95% CI: 0.04- 0.30) and management system (OR=8.51; 95% CI: 1.07-68.05) as risk factors for Brucella infection by RSA. However, location (OR=10.83; 95% CI: 5.48-21.39) and history of infertility (OR=2.62; 95% CI: 1.41-4.84) were identified as risk factors using RBT. Conclusion: Given the 10.96% to 12.72% seroprevalence of brucellosis recorded in this study, we advocate control of the disease in dogs, and public health education for those at risk of infection. Again, further studies are required to elucidate the role of dogs in the epidemiology of brucellosis in Nigeria considering the conducive human-animal interface and ecological factors responsible for the transmission of the disease.Pan African Medical Journal 2016; 2

Direct detection of Mycobacterium tuberculosis with nitrate reductase assay and microscopic observation drug susceptibility

The global increase in tuberculosis drug resistant which is a threat to its control, require low cost method of diagnosis and detection. Available conventional and molecular methods consume time, and are expensive for countries with high disease burden. Nitrate Reductase Assay (NRA) and Microscopic Observation Drug Susceptibility (MODS) performance to directly detect tuberculosis resistance to four drugs was evaluated. The NRA (liquid and solid) and MODS performance of smear-positive sputum samples were evaluated; Sensitivities and specificities were compared with Proportion Method (PM). Sensitivity and specificity of liquid NRA (LNRA) were 90% and 98% (rifampicin), 81.8% and 100% (isoniazid), 88.9% and 98.1% (streptomycin), and 57.1% and 94.4% (ethambuthol). Also, the sensitivity and specificity for solid NRA (SNRA) were 69.2% and 98.3% (rifampicin); 100% and 100% (isoniazid); 88.9% and 95.2% (streptomycin); 70% and 80.6% (ethambuthol). Moreover, For MODS, rifampicin and isoniazid sensitivity and specificity was 100%, it was 100% and 98.1% for streptomycin, and 71.4% and 98.2% for ethambuthol. At day 14, the results available for LNRA, SNRA and MODS were 93%, 68.5% and 100% respectively. The agreement between LNRA and PM was 97% (RIF, INH and SM) and 90% (EMB). For SNRA, it was 93% (RIF), 100% (INH), 94% (SM) and 89% (EMB). While for MODS, it was 100% (RIF and INH), 98% (SM) and 95% (EMB). Direct NRA and MODS are sensitive, reliable and fast for antituberculosis drug susceptibility; they have potential to effectively and reliably detect drug resistant tuberculosis in the low resource countries. DOI: http://dx.doi.org/10.5281/zenodo.429588

Seroprevalence and associated factors of brucellosis and Q-fever in cattle from Ibarapa area, Oyo state, south-western Nigeria

Introduction: a cross-sectional study was conducted to determine the seroprevalence and associated factors of brucellosis and Q-fever among cattle in a rural setting in Oyo State, Nigeria. Methods: one hundred and fourty nine serum samples (24 males; 125 female) from 16 cattle herds were collected and screened. The Rose Bengal Plate test (RBPT) and competitive Enzyme-Linked Immunosorbent Assay (cELISA) were used for brucellosis while indirect Enzyme-Linked Immunosorbent Assay (iELISA) was used for Q-fever. Further, a checklist was used to collect data on cattle sampled. Data were analyzed using STATA 12. Results: serum analysis revealed that 11.4% (17/149) and 6.7% (10/149) were seropositive by RBPT and cELISA respectively for brucellosis, while 23.5% (35/149) were seropositive by iELISA for Q-fever. A significant association was detected between cattle age (OR=27.7; 95% CI: 2.34-449.86), herd size (OR=10.53; 95% CI: 1.85-60.53) and seropositivity to Brucella infection. Also, there was a significant association between breed (OR=6.69; 95% CI: 1.7-28.74), herd size (OR=4.25; 95% CI: 1.31-13.85) of cattle and seropositivity to Coxiella burnetii infection. Importantly, the only significant associated factor to cattle herd seropositivity to Brucella and C. burnetii infections was the method of handling aborted foetuses. Conclusion: the study revealed that brucellosis and Q-fever are prevalent among cattle in the study area. Thus, there is a need for further studies to provide better insight into the epidemiology of both diseases and particularly Q-fever. This becomes imperative in the study area and generally in Nigeria given the dearth of information about the diseases in pastoralist communities who are at grave risk of infection at the human-animal-ecosystem interface

Seroprevalence of brucellosis and associated factors among livestock slaughtered in Oko-Oba abattoir, Lagos State, southwestern Nigeria

Introduction: Brucella infection, a neglected tropical zoonosis, poses public health threat to abattoir workers in developing countries including Nigeria. Oko-Oba abattoir is one of the largest abattoirs in the country that collects livestock from different parts of the country. This study determined the prevalence and factors associated with seropositivity of brucellosis among livestock slaughtered at Oko-Oba abattoir. Methods: a cross-sectional study was conducted from January to May 2018. A total of 473 serum samples were collected from livestock at the abattoir and tested for antibodies to Brucella species using the Rose Bengal Plate Test (RBPT) and indirect Enzyme Linked Immunosorbent Assay (iELISA). Data were analyzed using descriptive statistics and chi square test (p < 0.05). Results: overall seroprevalence values were 15.3% (RBPT) and 16.3% (iELISA) among the livestock slaughtered at the Oko-Oba abattoir. Seroprevalence of 17.2% (RBPT) and 15.8% (iELISA) in cattle; 15.1% (RBPT) and 14.5% (iELISA) in goat; and 8.3% (RBPT) and 23.3% (iELISA) in sheep were obtained. Higher seroprevalence were recorded among females in cattle (18.8% iELISA) and sheep (23.1% iELISA) while male goats had average value higher (14.7% iELISA) than the female (p > 0.05). Conclusion: presence of Brucella infection among slaughtered livestock was confirmed at Oko-Oba abattoir, Lagos State, Nigeria and poses a threat to abattoir workers and public health. Control of the disease in livestock and use of personal protective gear is recommended

Prevalence of bovine brucellosis in slaughtered cattle and barriers to better protection of abattoir workers in Ibadan, South-Western Nigeria

Introduction: Brucellosis is a neglected zoonosis of public health importance. This study was conducted to determine the prevalence and risk factors of brucellosis among slaughtered cattle as well as challenges to the protection of abattoir workers in Nigeria.Methods: A slaughterhouse study was conducted in a major abattoir in Ibadan from March to August, 2013. To diagnose brucellosis, serum samples from 1,241 slaughtered cattle were tested using Rose-Bengal test (RBT) and competitive enzyme-linked immunosorbent assay (cELISA); again, 57 milk samples were tested with milk ring test (MRT) and indirect ELISA (iELISA). Furthermore, a survey on the usage of personal protective equipment (PPE) and challenges to its use by abattoir workers was done. Data were analysed using Stata 12. Results: Seroprevalence by RBT was 7.8%; 77.3% (75/97) of these were  corroborated by cELISA. Prevalence in milk samples by MRT and indirect ELISA were 33.3% and 3.5%, respectively. Sex (OR: 2.5; 95%CI:1.3-4.5) was the factor significantly associated with Brucella seropositivity. None of the abattoir workers used standard protective overalls; while, 99.6% of the meat handlers and 84.1% of the butchers worked barefoot. Most of the workers (75.7%) wore no protective gloves. The respondents agreed that provision of free PPE and sanctions against non-users would encourage its use. Conclusion: Our findings indicate moderate prevalence (7.8%) of bovine brucellosis with sex of cattle being a risk factor. A notable barrier to better protection of abattoir workers against brucellosis is perceived inconvenience arising from use of gloves. Therefore, preventive and control measures against brucellosis must include education and use of PPE among abattoir workers

Prevalence and molecular characterization of Mycobacterium tuberculosis complex in cattle and humans, Maiduguri, Borno state, Nigeria: a cross-sectional study

Abstract Introduction Globally, the highest burden of bovine and human tuberculosis resides in Africa and Asia. Tuberculosis (TB) is the second leading single infectious killer after severe acute respiratory syndrome corona virus-2 (SARSCOV-2). Bovine TB remains a treat to wild and domesticated animals, humans and hinders international trade in endemic countries like Nigeria. We aimed at determining the prevalence of bovine and human tuberculosis, and the spoligotypes of Mycobacterium tuberculosis complex in cattle and humans in Maiduguri. Methods We conducted a cross sectional study on bovine and human tuberculosis in Maiduguri, Borno state. We calculated sample size using the method of Thrusfield. Lesions suggestive of TB from 160 slaughtered cattle were obtained from Maiduguri Central Abattoir. Sputum samples from humans; 82 abattoir workers and 147 suspected TB patients from hospitals/clinics were obtained. Lesions and sputum samples were cultured for the isolation of Mycobacterium spp. Positive cultures were subjected genus typing, deletion analysis and selected isolates were spoligotyped. Data was analysed using SPSS VERSION 16.0. Results Prevalence of 32.5% (52/160) was obtained in cattle. Damboa local government area (LGA), where majority of the infected animals were obtained from had 35.5% bTB prevalence. All categories analysed (breed, age, sex, body conformation and score) had P-values that were not significant (P > 0.05). Sputum culture revealed a prevalence of 3.7% (3/82) from abattoir workers and 12.2% from hospitals/clinics. A significant P-value (0.03) was obtained when positive culture from abattoir and that of hospitals/clinics were compared. Out of the 52 culture positive isolates obtained from cattle, 26 (50%) belonged to M. tuberculosis complex (MTC) and 17/26 (65.4%) were characterized as M. bovis. In humans, 7/12 (58.3%) MTC obtained were characterized as M. tuberculosis. Spoligotyping revealed SB0944 and SB1025 in cattle, while SIT838, SIT61 of LAM10_CAM and SIT1054, SIT46 of Haarlem (H) families were obtained from humans. Conclusions Cattle in Damboa LGA need to be screened for bTB as majority of the infected animals were brought from there. Our findings revealed the presence of SB0944 and SB1025 spoligotypes from cattle in Borno state. We isolated M. tuberculosis strain of the H family mainly domiciled in Europe from humans