Granulomatous lymphadenitis in a dog caused by Mycobacterium intracellulare

Background: Mycobacteriosis is caused by bacteria belonging to the genus Mycobacterium, with considerable zoonoticpotential and risk to public health. Infection in dogs is rare and is usually associated with immunosuppression, resultingfrom eating meat or contact with contaminated soil or fomites. Dogs are also known as potential sources for the spread ofatypical tuberculosis in humans and other animals. This paper aims to describe the clinical, cytological, histopathological,and molecular findings of a male canine seen at University Veterinary Hospital of Cuiabá, Mato Grosso, with generalizedlymphadenomegaly associated Mycobacterium intracellulare infection.Case: A 2-year-old male Lhasa Apso dog was referred to the University Veterinary Hospital in Cuiabá city, located in theMidwest region of Brazil. The patient had a history of intermittent claudication of the left pelvic limb for approximately6 months and lymphadenomegaly with progression for approximately 2 months. The dog had wheezing and generalizedlymphadenopathy (submandibular, axillary, and popliteal lymph nodes); cryptorchidism was also observed. A completeblood count revealed nonspecific results, and in the serum biochemical profile, the values of urea, creatinine, albumin, andalanine aminotransferase were within the reference range. No changes were observed on the radiography of the femurotibiopatellar joints. Considering the generalised lymphadenopathy, fine needle aspiration cytology and histopathologicalexamination through biopsy of the lymph nodes was performed. On the cytology and histopathology, numerous negativeimages of moderately refringent bacillary structures distending the cytoplasm from the macrophages was found. Thesamples were also subjected to special Ziehl-Neelsen staining, which confirmed an accentuated and diffuse granulomatouslymphadenitis associated with alcohol...(AU)

Granulomatous lymphadenitis in a dog caused by Mycobacterium intracellulare

Background: Mycobacteriosis is caused by bacteria belonging to the genus Mycobacterium, with considerable zoonoticpotential and risk to public health. Infection in dogs is rare and is usually associated with immunosuppression, resultingfrom eating meat or contact with contaminated soil or fomites. Dogs are also known as potential sources for the spread ofatypical tuberculosis in humans and other animals. This paper aims to describe the clinical, cytological, histopathological,and molecular findings of a male canine seen at University Veterinary Hospital of Cuiabá, Mato Grosso, with generalizedlymphadenomegaly associated Mycobacterium intracellulare infection.Case: A 2-year-old male Lhasa Apso dog was referred to the University Veterinary Hospital in Cuiabá city, located in theMidwest region of Brazil. The patient had a history of intermittent claudication of the left pelvic limb for approximately6 months and lymphadenomegaly with progression for approximately 2 months. The dog had wheezing and generalizedlymphadenopathy (submandibular, axillary, and popliteal lymph nodes); cryptorchidism was also observed. A completeblood count revealed nonspecific results, and in the serum biochemical profile, the values of urea, creatinine, albumin, andalanine aminotransferase were within the reference range. No changes were observed on the radiography of the femurotibiopatellar joints. Considering the generalised lymphadenopathy, fine needle aspiration cytology and histopathologicalexamination through biopsy of the lymph nodes was performed. On the cytology and histopathology, numerous negativeimages of moderately refringent bacillary structures distending the cytoplasm from the macrophages was found. Thesamples were also subjected to special Ziehl-Neelsen staining, which confirmed an accentuated and diffuse granulomatouslymphadenitis associated with alcohol...

Genetic diversity of Mycobacterium avium complex strains isolated in Argentina by MIRU-VNTR.

Mycobacterium avium sp. avium (MAA), M. avium sp. hominissuis (MAH), and M. avium sp. paratuberculosis (MAP) are the main members of the M. avium complex (MAC) causing diseases in several hosts. The aim of this study was to describe the genetic diversity of MAC isolated from different hosts. Twenty-six MAH and 61 MAP isolates were recovered from humans and cattle, respectively. GenoType CM® and IS1311-PCR were used to identify Mycobacterium species. The IS901-PCR was used to differentiate between MAH and MAA, while IS900-PCR was used to identify MAP. Genotyping was performed using a mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) scheme (loci: 292, X3, 25, 47, 3, 7, 10, 32) and patterns (INMV) were assigned according to the MAC-INMV database (http://mac-inmv.tours.inra.fr/). Twenty-two (22/26, 84·6%) MAH isolates were genotyped and 16 were grouped into the following, INMV 92, INMV 121, INMV 97, INMV 103, INMV 50, and INMV 40. The loci X3 and 25 showed the largest diversity (D: 0·5844), and the global discriminatory index (Hunter and Gaston discriminatory index, HGDI) was 0·9300. MAP (100%) isolates were grouped into INMV 1, INMV 2, INMV 11, INMV 8, and INMV 5. The HGDI was 0·6984 and loci 292 and 7 had the largest D (0·6980 and 0·5050). MAH presented a higher D when compared with MAP. The MIRU-VNTR was a useful tool to describe the genetic diversity of both MAH and MAP as well as to identify six new MAH patterns that were conveniently reported to the MAC-INMV database. It was also demonstrated that, in the geographical region studied, human MAC cases were produced by MAH as there was no MAA found among the human clinical samples.

Tuberculosis in swine co-infected with Mycobacterium avium subsp. hominissuis and Mycobacterium bovis in a cluster from Argentina.

SUMMARY In Argentina little is known about the epidemiology of tuberculosis (TB) infection in swine. We characterized the epidemiological dynamics of Mycobacterium avium complex (MAC) infection in a swine population of Argentina using molecular tools and spatial analysis techniques. Isolates (n = 196) obtained from TB-like lesions (n = 200) were characterized by polymerase chain reaction. The isolates were positive to either M. bovis (IS6110) (n = 160) or M. avium (IS1245) (n = 16) while the remaining 20 (10.2%) isolates were positive to both M. bovis and M. avium. The detection of both bacteria together suggests co-infection at the animal level. In addition, MAC-positive isolates (n = 36) were classified as M. avium subsp. avium (MAA) (n = 30) and M. avium subsp. hominissuis (MAH) (n = 6), which resulted in five genotypes when they were typed using mycobacterial interspersed repetitive unit, variable number of tandem repeats (MIRU-VNTR). One significant (P = 0.017) spatial clustering of genotypes was detected, in which the proportion of MAH isolates was larger than expected under the null hypothesis of even distribution of genotypes. These results show that in Argentina the proportion of TB cases in pigs caused by M. avium is larger than that reported in earlier studies. The proportion of M. bovis-MAC co-infections was also higher than in previous reports. These results provide valuable information on the epidemiology of MAC infection in swine in Argentina.