Cutaneous lesion caused by Mycobacterium tuberculosis in a dog

A 5-month-old female mixed-breed dog was examined because of nonhealing wounds in the right submandibular region. Treatment with antibiotics and surgical excision was ineffective. Specimens of the right mandibular lymph node and surrounding tissues were submitted for bacteriologic culturing, and Mycobacterium tuberculosis was isolated. The dog was euthanatized. The risk of infection of human beings who associate with dogs that have cutaneous wounds caused by mycobacteria is unknown.     

Outbreak of tuberculosis caused by Mycobacterium caprae in a zoological garden

In the autumn of 2004, tuberculosis caused by Mycobacterium caprae occurred in a zoo in Slovenia. A dromedary camel (Camelus dromedarius) was killed after a history of progressive emaciation. Necropsy findings indicated disseminated tuberculosis, which was confirmed by cultivation of M. caprae. Consequently, a tuberculin skin test was performed in all epidemiologically linked animals and another dromedary camel and six bison (Bison bison) were positive and killed. Mycobacterium caprae was isolated from two bison while M. scrofulaceum and Mycobacterium spp. were found in two other bison, respectively. The second dromedary camel was found to be negative for mycobacteria under both microscopic and culture tests. The isolates were investigated with commercial identification kits, IS6110 PCR, IS6110 restriction fragment length polymorphism analysis, spoligotyping and mycobacterial interspersed repetitive units typing. Genotyping results revealed that the dromedary camel and the two bison were infected by the same M. caprae.     

Accidental infection of veterinary personnel with Mycobacterium tuberculosis at necropsy: a case study

Mycobacterium tuberculosis is the main cause of human tuberculosis. Infection in companion animals is mainly acquired from close contact to a diseased human patient and hence rarely diagnosed in countries with low tuberculosis incidence rates. Therefore the general awareness of the disease might be low. Here we report the potential risk of infection for veterinary personnel with M. tuberculosis during the clinical and pathological examination of a dog with unexpected disseminated tuberculosis. The dog had presented with symptoms of a central nervous system disease; rapid deterioration prevented a complete clinical workup, however. Post-mortem examination revealed systemic mycobacteriosis, and M. tuberculosis was identified by PCR amplification of DNA extracts from paraffin-embedded tissue sections and spoligotyping. Contact investigations among the owners and veterinary personnel using an IFN-γ release assay indicated that the index dog did not infect humans during its lifetime. Serological and IFN-γ release assay results of one of two cats in direct contact with the index dog, however, suggested that transmission of M. tuberculosis might have occurred. Importantly, all three pathologists performing the necropsy on the dog tested positive. Accidental infection was most likely due to inhalation of M. tuberculosis containing aerosols created by using an electric saw to open the brain cavity. As a consequence routine necropsy procedures have been adapted and a disease surveillance program, including tuberculosis, has been initiated. Our results highlight the importance of disease awareness and timely diagnosis of zoonotic infectious agents in optimizing work safety for veterinary personnel.     

Pulmonary Mycobacterium tuberculosis (Beijing strain) infection in a stray dog

Mycobacterium tuberculosis infection in dogs is rarely reported and has not previously been documented in South Africa. A case of a stray Maltese crossbreed dog with extensive multifocal pulmonary tuberculosis due to M. tuberculosis is described. Pulmonary granulomas in this case were poorly encapsulated and contained large numbers of acid-fast bacteria, highlighting the potential for infected companion animals to excrete the pathogen. Treatment of canine tuberculosis is generally not advised, and for this reason, euthanasia of diseased animals must be advocated in most instances. Physicians and veterinarians must be aware that companion animals with active disease caused by M. tuberculosis could act as a potential source of infection.     

An outbreak of tuberculosis by Mycobacterium bovis in coatis (Nasua nasua)

Mycobacterium tuberculosis complex, which includes Mycobacterium bovis, infrequently causes severe or lethal disease in captive wildlife populations. A dead coati from a wildlife triage center showing pulmonary lesions compatible with tuberculosis had raised suspicion of a potential disease caused by mycobacteria species and was further investigated. Four native coatis (Nasua nasua) with suspected mycobacterial infection were sedated, and bronchoalveolar lavages and tuberculin skin tests (TSTs) were performed. All animals tested positive upon TST. Mycobacterial culturing, Ziehl-Neelsen staining, and genetic testing were performed on postmortem samples and the etiologic agent was identified as M. bovis. Molecular genetic identification using a polymerase chain reaction panel was crucial to achieving a definitive diagnosis.     

Putative transmission of Mycobacterium tuberculosis infection from a human to a dog

A 3.5-year-old Yorkshire Terrier was evaluated for anorexia and vomiting; infection with Mycobacterium tuberculosis was diagnosed by use of histology, bacteriologic culture, and polymerase chain reaction (PCR) assay on various tissues. The dog was living with a human with an established M. tuberculosis infection. Findings were unique in that diagnosis of M. tuberculosis infection was obtained via PCR techniques, and isolates from the owner and dog were matched via restriction fragment length polymorphism fingerprinting. Dogs infected with M. tuberculosis from humans are most commonly infected via the respiratory tract. Clinical signs in dogs are variable and depend on the integrity of the immune system and the degree of dissemination. Diagnosis can often be obtained through histopathology and bacteriologic culture; additional diagnostic techniques are also available. Treatment of a dog with confirmed M. tuberculosis infection is controversial, and at least 6 months of multidrug treatment is required.     

Estimation of the spread of pathogenic mycobacteria in organic broiler farms by the polymerase chain reaction

Organic poultry breeding allows for increased exposure of birds to soil, faeces, and wildlife, which have been associated with the transmission of mycobacterial infections. Therefore the aim of this study was to investigate the spread of the major pathogenic mycobacteria in organically reared broilers in Greece using a diagnostic algorithm that relied on a combination of the polymerase chain reaction (PCR) and the restriction fragment length polymorphism analysis (RFLP). Liver, spleen and gonads from 81 to 150 days old broilers were aseptically collected post-mortem. 500 broilers from a population of 35,370, reared in the 25 registered as organic farms in Greece for the 2005 were used. DNA was isolated and incorporated to PCR targeted to 16S-rRNA gene (for Mycobacterium spp.), IS6110 (for Mycobacterium tuberculosis complex-MTBc), IS1245 (for Mycobacterium avium complex-MAC), IS901 (for M. avium subsp. avium-MAA) and hsp65 (for Mycobacterium genavense, by PCR-RFLP). The mean prevalence of mycobacteria detected by PCR with a 95% confidence interval was estimated to 4.4-8.8%. The relevant percentage with regard to the mycobacterial species that were included in this study was 0.17-2.03% for MAC, 2.11-3.39% for MTBc and 0.66-3.08% for mycobacteria not belonging to any of the above groups. None of the mycobacteria detected were identified as MAA or M. genavense. Considering that avian tuberculosis has been eradicated from conventional farms, the level and the pattern of positivity recorded here, indicates that our results may be associated with the specific conditions that apply to organic breeding.     

Fatal mycobacteriosis with hepatosplenomegaly in a young dog due to Mycobacterium avium.

Cases of disseminated Mycobacterium avium infections in dogs are rare because it appears that the species is innately resistant to infection. A 2-year-old, castrated, 5 kg Shih Tzu-Poodle-cross developed anemia, abdominal pain, lethargy, and splenomegaly. Histological examination of surgically removed spleen indicated marked granulomatous splenitis with myriad intracytoplasmic acid-fast bacterial rods. Ultrastructural examination revealed the presence of 3-4-microm-long mycobacteria in phagolysosomes of epithelioid macrophages. Tissue extract of lightly fixed spleen was positive for M. avium 16S ribosomal RNA and negative for M. tuberculosis complex IS6110 DNA by polymerase chain reaction testing. Anemia was associated with the presence of mycobacteria-infected macrophages in bone marrow. The animal's condition deteriorated, and euthanasia was performed after a clinical course of 2 months. The principal morphological findings at necropsy were severe diffuse granulomatous hepatitis, enteric lymphadenomegaly, and segmental granulomatous enteritis with intralesional mycobacteria present. Mycobacterium avium was cultured from enteric lymph nodes sampled at necropsy. The source of infection was not established but was presumed to be environmental with an enteric portal of entry.     

Multisystemic bovine mycobacteriosis in a pony with neurological signs and weight loss

This report describes the clinical, biochemical and histopathological findings of a case of disseminated, primary mycobacterial infection with Mycobacterium bovis in a pony presenting with neurological signs and weight loss. This report revisits tuberculosis as a potential differential diagnosis in horses at a time of relatively strong tuberculosis control in the UK and iterates the importance of post‐mortem examination as a diagnostic tool for clinicians. Key public health questions following exposure to mycobacterial pathogens are also discussed.     

Mycobacterium goodii infection in a dog with concurrent hyperadrenocorticism

Abstract A 9-year-old Boston terrier was diagnosed with multifocal, nodular panniculitis caused by an organism belonging to the Mycobacterium smegmatis group by histological evaluation and bacteriological identification. The mycobacterial species was identified by direct gene sequence analysis and confirmed to be Mycobacterium goodii. Treatment using doxycycline and ciprofloxacin was successfully implemented for the mycobacterial panniculitis over a period of 9 months. Concurrent pituitary-dependent hyperadrenocorticism (Cushing's disease) was also identified using routine diagnostic methods and mitotane therapy was implemented. There was follow-up for 14 months after cessation of antimicrobial therapy with no recurrence of mycobacterial infection. Although cutaneous infections are frequently recognized as complications of canine pituitary-dependent hyperadrenocorticism, concurrent mycobacterial panniculitis due to any rapidly growing mycobacterium has not previously been reported. This is the first confirmed case of mycobacterial panniculitis due to M. goodii infection in a dog and also the first of any rapidly growing mycobacterial infection in a dog with concurrent endogenous Cushing's disease.     

The comparative tuberculin test in guinea pigs using PPD extracts prepared from mycobacteria killed with phenol

Summary. Purified-protein-derivative (PPD) extracts were prepared from Mycobacterium tuberculosis (PPD-S), M. bovis (PPD-BS), M. avium (PPD-A) and M. kansasii (PPD-K), after killing the cultures with phenol. The reactions were assessed in guinea pigs sensitised to a range of mycobacteria, with a view to selecting a suitable pairing of the extracts to distinguish sensitivity due to M. tuberculosis or M. bovis from that due to other mycobacteria.
Sensitisation induced by M. bovis was best distinguished from others using PPD-S and PPD-A; for sensitisation by atypical mycobacteria, PPD-BS was better than PPD-S, used with either PPD-K or PPD-A, PPD-BS was more specific than PPD-S.
Using PPD-BS, PPD-A and PPD-K in a comparative test, 3 groups were recognised: those sensitive to M. bovis or M. tuberculosis (greatest reaction was to PPD-BS); those sensitive to M. avium, M. Intracellulare and M. scrofulaceum (greatest reaction was to PPD-A); those sensitive to M. kansasii, M. marium, M. gordonae and M. fortuitum (greatest reaction was to PPD-K).     

Bovine tuberculosis is more prevalent in cattle owned by farmers with active tuberculosis in central Ethiopia

A case control study was conducted between October 2004 and April 2005 to determine the prevalence of bovine tuberculosis (BTB) in cattle in central Ethiopia relative to the tuberculosis status of their owners. A total of 174 farmers (87 with active tuberculosis and 87 with no active tuberculosis), and 1041 cattle (506 owned by farmers with active tuberculosis and 535 by farmers without active tuberculosis) were included. The comparative intradermal cervical tuberculin test was used in cattle while clinical symptoms, chest X-ray and Ziehl-Neelsen staining were used for the diagnosis of tuberculosis in the farmers. In addition, mycobacterial culture, biochemical tests, and drug susceptibility tests were performed for the identification Mycobacterium spp. from both humans and cattle. The prevalence of BTB was threefold higher (odds ratio [OR]=4.2, 95% confidence interval [CI]=2.79-6.2) in cattle owned by farmers with active tuberculosis (24.3%) than in those owned by farmers who did not have active tuberculosis (8.6%). Cattle owned by farmers with active tuberculosis were four times more likely to have tuberculosis than cattle owned by farmers with no active tuberculosis. Furthermore, cattle owners who consumed raw milk were at greater risk (chi2=14.1, P<0.001, OR=3.34) of having active tuberculosis than those who consumed boiled milk. Of the 42 human isolates, 31 (74%) were Mycobacterium tuberculosis, seven (16%) were Mycobacterium bovis while four (10%) were considered a typical mycobacteria on the basis of biochemical and drug sensitivity tests. Of the 11 cattle isolates, two (18%) were Mycobacterium tuberculosis, five (46%) Mycobacterium bovis, and four (36%) were atypical mycobacteria. The prevalence of tuberculosis was higher in cattle owned by farmers with active tuberculosis than in cattle owned by farmers who did not have active tuberculosis, which could suggest possible transmission of Mycobacterium spp. between cattle and their owners.     

Prevalence of bovine tuberculosis in slaughter cattle in Kenya: a postmortem, microbiological and DNA molecular study

A study to determine the presence and prevalence of bovine tuberculosis in slaughter cattle in Kenya was carried out in two abattoirs from July to November 2009. Routine postmortem meat inspection was performed on a subpopulation of 929 cattle selected randomly from among 4,984. Carcases were inspected for gross tuberculous lesions which were then examined for acid-fast bacilli, (AFB), cultured for isolation of mycobacteria and the isolates characterised by DNA molecular analysis. Of the carcases examined, 176 (18.95?%, 95?% CI) had lesions suggestive of tuberculosis. AFB were observed in 63/176 of the lesioned cattle and mycobacteria were isolated from 64 of them. The isolates were identified as Mycobacterium bovis (19/64), Mycobacterium tuberculosis, (2/64) and mycobacteria other than tuberculosis (43/64). The prevalence of M. bovis by molecular analysis was 2.05?% (95?% CI). This study documents for the first time the presence of bovine tuberculosis among slaughter cattle in Kenya. There is therefore a need to formulate and implement control programmes in order to minimise transmission among animals and to humans. Isolation of M. tuberculosis from cattle underscores the risk tuberculous humans pose to animals.     

Diagnosis of Mycobacterium bovis infection in calves sensitized by mycobacteria of the avium/intracellulare group

Because of the frequent exposure of cattle to mycobacteria of the avium/intracellulare group, an investigation was carried out into the possible repercussions thereof on the diagnosis of bovine tuberculosis. Three calves from a bovine tuberculosis-free herd, scored avian reactors in the gamma-interferon assay for bovine tuberculosis, were sedated and inoculated endotracheally with a virulent Mycobacterium bovis strain. Then, three other avian reactors were housed with the above donor calves. Mycobacterium bovis was isolated from the nasal swabs of the three endotracheally infected, donor calves. On these samples, TB complex-specific polymerase chain reaction (PCR) tests for IS6110 were also positive, albeit with a different time kinetics. The three contact-infected calves showed clear immunological signs of infection; however, their nasal swabs were always PCR-negative and only Mycobacterium avium was isolated. In the endotracheally infected donor calves there was a rise of the gamma-interferon responses to avian and bovine purified protein derivative (PPD) tuberculins, which reached the same stable plateau levels over the whole experiment. The above effect was also observed in the contact-infected calves, even though the response to avian PPD tuberculin always remained at a higher level. By using conventional bovine and avian PPD tuberculins, the comparative intradermal test was generally positive in endotracheally infected, as opposed to contact-infected calves; a positive intradermal test for M. bovis was obtained in two contact-infected calves by different bovine PPD tuberculins based on M. bovis bacillus Calmette-Guerin (BCG) secreted or somatic antigens. It was concluded that M. bovis infection may be concealed for some time in cattle sensitized by mycobacteria of the avium/intracellulare group and that different diagnostic procedures should be adopted for such animals.     

Tuberculosis in domesticated red deer: Comparison of purified protein derivative and the specific protein MPB70 for in vitro diagnosis

The use of a Mycobacterium bovis-specific protein, mycobacterial protein bovis 70 (MPB70), was compared with complex, M bovis-derived purified protein derivative (bovine PPD), for its ability to improve the diagnostic precision of in vitro assays for tuberculosis in farmed deer. A combination of lymphocyte transformation and enzyme-linked immunosorbent assay (ELISA) was used to differentiate between specific M bovis reactivity and crossreactivity due to sensitisation with saprophytic mycobacteria such as Mycobacterium avium. In the lymphocyte transformation assay the response of mononuclear cells, from red deer, to MPB70 was found to be more specific, but less sensitive, as an indicator of infection by M bovis when compared with the complex antigen bovine PPD. When used in conjunction with bovine PPD alone, MPB70 was found to increase the specificity of the ELISA in diagnosing animals with disease.     

An investigation of the effects of secondary processing on Mycobacterium spp. in naturally infected game meat and organs

The risk for humans to contract bovine tuberculosis through the consumption of undercooked game meat as well as biltong (traditionally dried game meat) is a concern. The survival potential of Mycobacterium bovis during the cooking and drying processes was researched in a preceding study on beef and the positive results compelled the authors to investigate the results with a similar preliminary study on game meat. Muscular, lymphatic and visceral tissues from skin test positive African buffalo (Syncerus caffer) and greater kudu (Tragelaphus strepsiceros) with tuberculous lesions were collected from the Hluhluwe iMfolozi Park during the park's culling programme. The different tissues were exposed to cooking and the muscular tissue to the drying process prior to culture. All acid-fast isolates were analysed by polymerase chain reaction for the presence of Mycobacterium bovis. All tissues were found negative for Mycobacterium bovis but non-tuberculous mycobacteria were isolated from kidney, liver, heart and lymph nodes. The results showed that these processes will kill Mycobacterium bovis but the unexpected recovery of non-tuberculous mycobacteria suggests possible survival and resistance characteristics of these strains which might be of veterinary public health interest.     

Immune responses in bovine tuberculosis: towards new strategies for the diagnosis and control of disease

In several countries, bovine tuberculosis (caused by infection with Mycobacterium bovis) is a major economic problem with the potential to be a significant public health risk. Where traditional test-and-slaughter policies based on skin testing with tuberculin have not been fully successful, new tools including additional diagnostic tests and improved vaccines are required urgently. This paper considers how recent developments in knowledge of immune responses and mycobacterial antigens can be used in the logical development of more efficient strategies for the identification of infected cattle.     

Molecular analyses of mycobacteria other than the M. tuberculosis complex isolated from Northern Ireland cattle

Mycobacteria other than the Mycobacterium tuberculosis complex (MOTT), isolated from Northern Ireland cattle, were identified by PCR amplification of the 16S rRNA gene, and subsequent reverse cross blot hybridisation and sequence analyses. Elucidation of the MOTT species was to facilitate specificity testing of new and existing diagnostic test reagents for bovine tuberculosis. The presence of the genes for potential diagnostic antigens: MPB70, MPB64, ESAT-6 and CFP-10 in the isolated MOTT species was investigated. Molecular analyses of cultured isolates from bovine lymph node specimens of 48 cattle identified a wide variety of mycobacterial species including Mycobacterium nonchromogenicum, Mycobacterium malmoense, Mycobacterium bohemicum, Mycobacterium paratuberculosis, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium holsaticum, Mycobacterium palustre, Mycobacterium sp. IWGMT 90210, Mycobacterium sp. LIV-2129, a potentially novel mycobacterial species (EMBL/GenBank/DDBJ Accession Number AJ617495) and Rhodococcus equi. Apart from M. kansasii, the results of traditional (standard phenotypic and biochemical) and molecular identification methods did not correlate well, with traditional methods identifying fewer species. Most of the species identified were either recognised pathogenic or potential pathogenic species. The genes for ESAT-6, CFP-10 and, unusually, MPB64 were detected in M. kansasii only. The MPB70 gene was not detected in any of the species. This study supported restricted species distribution of these genes as well as identifying a different range of MOTT species that could be included in specificity testing of new diagnostic reagents for bovine tuberculosis.     

Mycobacterium kansashi infection in a bontebok (Damaliscus pygaragus dorcas) herd: diagnostic challenges in differentiating from the Mycobacterium tuberculosis complex

Two adult female bontebok (Damaliscus pygarus dorcas) were euthanized because of signs of pneumonia and weakness (case 1), and a nonresponsive lameness with draining fistula (case 2). Necropsy findings were similar in both cases and consisted of disseminated granulomatous lesions in the liver, kidneys, spleen, lungs, pleural surfaces, and multiple lymph nodes. Mycobacterium kansasii was isolated from both cases after multiple attempts on a variety of samples by two laboratories. The remaining four animals in the herd were tested for antibody responses using the Chembio ElephantTB STAT-PAK, DPP VetTB kits, and multi-antigen print immunoassay (MAPIA), for immune reaction using the intradermal tuberculin test, and by tracheal wash cultures, and thoracic radiographs. Banked serum samples collected in 2005 and obtained from the original institution, revealed 1/9 (11.11%) seropositive animals using the three immunoassays. Retesting the current herd in 2008 showed 2/6 (33.33%) seropositive animals by the three tests, with MAPIA demonstrating antibody reactivity to MPB83 and MPB70 proteins. Inconsistent intradermal tuberculin test results, cross-reactivity in serologic assays designed for tuberculosis detection, difficulty in obtaining definitive identification by culture, and inability to identify a source of infection created challenges in distinguishing the atypical mycobacteriosis due to M. kansasii from the initially suspected tuberculous infection in this herd. Owing to regulatory considerations, differences in host-to-host transmission, and source of infection between Mycobacterium tuberculosis complex and nontuberculous mycobacteria, correct diagnosis is crucial for management of these diseases in wildlife species.