Mycobacterium bovis cervical lymphadenitis: A representative case and review

SUBFOVEAL CHOROIDAL TUBERCULOMA IN A HEALTHY YOUNG WOMAN CAUSED BY MYCOBACTERIUM BOVIS

PURPOSE

To describe a case of a macular tuberculoma in a young and healthy woman after developing a tuberculous lymphadenitis caused by Mycobacterium bovis .

METHODS

Retrospective case report.

RESULTS

Tuberculous lymphadenitis caused by M. bovis was detected after biopsy and histological examination as well as polymerase chain reaction test testing of cervical lymph nodes in a 20-year-old patient. An interferon gamma was positive. Shortly starting antitubercular therapy, the patient developed visual deterioration caused by a single yellowish subretinal structure in the macula of the right eye. Optical coherence tomography showed a dome-shaped, hyperreflective, subfoveal choroidal lesion with subtle subretinal fluid. Antitubercular therapy with isoniazid, rifampicin, ethambutol, and pyrazinamide was performed, and the deescalation therapy with isoniazid and rifampicin was extended to 7 months. Further examinations showed regression of choroidal tuberculoma to a scar.

CONCLUSION

This is the first reported case of choroidal tuberculoma after tuberculous lymphadenitis caused by M. bovis .

Mycobacterium bovis and you: A comprehensive look at the bacteria, its similarities to Mycobacterium tuberculosis, and its relationship with human disease

While Mycobacterium tuberculosis is the primary cause of tuberculosis in people, multiple other mycobacteria are capable of doing so. With the World Health Organization's goal of a 90% reduction in tuberculosis by 2035, all tuberculous mycobacteria need to be addressed. Understanding not only the similarities, but importantly the differences between the different species is crucial if eradication is ever to be achieved. Mycobacterium bovis, while typically thought of as a disease of cattle, remains a possible source of human infection worldwide. Although this species' genome differs from Mycobacterium tuberculosis by only 0.05%, significant differences are present, creating unique challenges to address. This review focuses on features which distinguish this bacterium from Mycobacterium tuberculosis, including differences in origin, structure, environmental persistence, host preferences, infection and disease, host immune response, diagnostics and treatment.

Zoonotic Tuberculosis in Humans: Control, Surveillance, and the One Health Approach

Zoonotic tuberculosis is a reemerging infectious disease in high-income countries and a neglected one in low- and middle-income countries. Despite major advances in its control as a result of milk pasteurization, its global burden is unknown, especially due the lack of surveillance data. Additionally, very little is known about control strategies. The purpose of this review was to contextualize the current knowledge about the epidemiology of zoonotic tuberculosis and to describe the available evidence regarding surveillance and control strategies in high-, middle-, and low-income countries. We conducted this review enriched by a One Health perspective, encompassing its inherent multifaceted characteristics. We found that the burden of zoonotic tuberculosis is likely to be underreported worldwide, with higher incidence in low-income countries, where the surveillance systems are even more fragile. Together with the lack of specific political commitment, surveillance data is affected by lack of a case definition and limitations of diagnostic methods. Control measures were dependent on risk factors and varied greatly between countries. This review supports the claim that a One Health approach is the most valuable concept to build capable surveillance systems, resulting in effective control measures. The disease characteristics and suggestions to implement surveillance and control programs are discussed.

Seroprevalence and molecular characterization of Mycobacterium bovis infection in camels (Camelus dromedarius) in the Delta region, Egypt

AIM

This study aimed to determine the prevalence rates of Mycobacterium infection in camel sera collected before slaughter and gross lesion tissue collected postmortem (PM) using enzyme-linked immunosorbent assay (ELISA), bacteriological culture, and polymerase chain reaction (PCR). In addition, serum samples from humans who had occupational contact with camels were tested by ELISA and sputum sample by culture.

MATERIALS AND METHODS

ELISA was performed on serum samples antemortem. In addition, bacteriological culture and PCR were conducted after PM. Tuberculosis infection was identified in humans who had contact with camels using ELISA for serum samples and culture for sputum samples.

RESULTS

Tuberculous lesions were detected in 184 of 10,903 camels (1.7%). The ELISA results revealed that of the 184 examined camel serum samples, 124 (67.39%) were positive and all 20 camel serum samples that had no associated tuberculous lesions were negative. Moreover, only one of 48 (2.08%) human serum samples was positive by ELISA. Mycobacterial culture revealed 112 isolates from the 184 examined camel samples (60.87%), while human sputum sample cultures were all negative. PCR analysis identified the mpb70 gene in three of seven randomly tested samples.

CONCLUSION

Gene sequencing was performed on two samples and the sequences were submitted to the National Center for Biotechnology Information GenBank (accession numbers MF990289 and MG59479). A phylogenetic tree was constructed based on the partial DNA sequences of the mpb70 gene; the similarity between the isolates was 98.1%. The similarities between the two isolates and the standard strains of Mycobacterium bovis in GenBank were 98.1% and 100%, respectively. Further investigation on the antemortem detection of M. bovis infection in camels is needed to decrease public risk.

Molecular Epidemiology of Mycobacterium bovis in Humans and Cattle

Bovine tuberculosis (bTB), caused by Mycobacterium bovis (M. bovis), is a serious re-emerging disease in both animals and humans. The evolution of the Multi- and Extensively drug-resistant M. bovis strains (MDR-TB and XDR-TB) represents a global threat to public health. Worldwide, the disease is responsible for great economic losses in the veterinary field, serious threat to the ecosystem, and about 3.1% of human TB cases, up to 16% in Tanzania. Only thorough investigation to understand the pathogen's epidemiology can help in controlling the disease and minimizing its threat. For this purpose, various tools have been developed for use in advanced molecular epidemiological studies of bTB, either alone or in combination with standard conventional epidemiological approaches. These techniques enable the analysis of the intra- and inter-species transmission dynamics of bTB. The delivered data can reveal detailed insights into the source of infection, correlations among human and bovine isolates, strain diversity and evolution, spread, geographical localization, host preference, tracing of certain virulence factors such as antibiotic resistance genes, and finally the risk factors for the maintenance and spread of M. bovis. They also allow for the determination of epidemic and endemic strains. This, in turn, has a significant diagnostic impact and helps in vaccine development for bTB eradication programs. The present review discusses many topics including the aetiology, epidemiology and importance of M. bovis, the prevalence of bTB in humans and animals in various countries, the molecular epidemiology of M. bovis, and finally applied molecular epidemiological techniques.