Disseminated Mycobacterium haemophilum infection in an ASSAM trinket snake (Elaphe frenata)

Coinfection by Mycobacterium marinum and Mycolicibacterium fortuitum in a captive adult diamondback water snake causing disseminated mycobacteriosis with acute cutaneous ulceration

An adult male captive diamondback water snake (Nerodia rhombifer) was found dead after a 1-d history of lethargy and cutaneous ulcers. The snake had eaten 2 sunfish (Mola spp.) 5 d before death. Gross examination revealed white-to-tan nodules in the lung and liver and segmental intestinal impactions with digested fish. Histopathology confirmed disseminated granulomas with numerous intrahistiocytic acid-fast bacteria in the skin, skeletal muscle, lung, liver, and intestines. Mycobacterium marinum and Mycolicibacterium fortuitum were identified by culture of the hepatic granuloma, followed by PCR and rpoB gene sequencing. To our knowledge, this is the first description of M. marinum and M. fortuitum coinfection in this species. Although M. fortuitum has been isolated from reptiles, lesions associated with its presence in tissues have not been described previously. Interestingly, the mineralization within granulomas that we observed in our case is not reported in mycobacterial infection in reptiles, whereas this finding is common in mammals.

Isolation and Molecular Identification of Nontuberculous Mycobacterium from Different Species of Fish in Karbala Province, Iraq

This study was designed for isolation and molecular identification of Nontuberculous Mycobacterium (NTM) from fish during the period between October and December 2017 from Karbla province, Iraq. This study included 200 fresh fish samples from four different species including Spondyliosoma cantharus, Liza abu, Carassius carassius and Cyprinuscarpio. Three samples of each fish were taken including gills, muscles and all internal organs. The samples were processed by decontamination, concentration of 4% sodium hydroxide, and 0.1 ml of sediment was streaking on Löwenstein Johnson (LJ) media; then the bacterial cultures were incubated at 28-30 °C for 3days up to 4 weeks and suspected colonies were stained with acid fast stain to confirm the presence of Mycobacterium. Further identification, biochemical tests were carried out to confirm the diagnosis of isolates, PCR was done using 16s RNA gene for all isolates, hsp65 gene was used in unidentified NTM spp and to confirm the others. Results revealed that out of 200 fish samples, 19 isolates 9.5% were identified as NTM belonged to Rapid Growth Mycobacterium (RGM). of the total isolates, 18.26 % was investigated from Liza abu (Kishni, Abu khraiza). NTM (RGM) isolates on spp level identified six spp of these isolates. M. porcinum was 26.32% which was followed by M. fortuitum of 21.05%, others included M. neworleansense and M. mucogenicum 10.5% of each, M. cosmeticum and M. pallens 5.26% of each. The distribution of NTM spp in the fish organs, nine out of 19 (47.37%) NTM isolate were recovered from gills followed by muscles 36.84 %, while 15.79% from internal organs. These results were the first study concerning isolation of these spp of NTM from fish in Iraq, and some spp are not reported in other studies. This study concluded that the fish is an importance source or reservoir for NTM, especially the pathogenic spp.

Non-tuberculous Mycobacterium species causing mycobacteriosis in farmed aquatic animals of South Africa

BACKGROUND

Mycobacteriosis caused by non-tuberculous mycobacteria (NTM), is among the most chronic diseases of aquatic animals. In addition, fish mycobacteriosis has substantial economic consequences especially in the aquaculture and fisheries industry as infections may significantly decrease production and trade. Some fish NTM pathogens are highly virulent and zoonotic; as such, infection of aquaria with these pathogens is a public health concern. In this study, we report isolation of nine different NTM species from sixteen aquatic animals including different fish species, frogs and a crocodile. Given the clinical significance of Mycobacterium marinum and its close relation to Mycobacterium tuberculosis, as well as the significance of ESAT 6 and CFP-10 secretion in mycobacterial virulence, we analysed the esxA and esxB nucleotide sequences of M. marinum isolates identified in this study as well as other mycobacteria in the public databases.

RESULTS

Mycobacterium shimoidei, Mycobacterium marinum, Mycobacterium chelonae, Mycobacterium septicum /M. peregrinum and Mycobacterium porcinum were isolated from gold fish, Guppy, exotic fish species in South Africa, koi and undefined fish, Knysna seahorse, as well Natal ghost frogs respectively, presenting tuberculosis like granuloma. Other NTM species were isolated from the studied aquatic animals without any visible lesions, and these include Mycobacterium sp. N845 T, Mycobacterium fortuitum, a member of the Mycobacterium avium complex, and Mycobacterium szulgai. Phylogenetic analysis of mycobacteria, based on esxA and esxB genes, separated slow growing from rapidly growing mycobacteria as well as pathogenic from non-pathogenic mycobacteria in some cases.

CONCLUSIONS

Isolation of the different NTM species from samples presenting granuloma suggests the significance of these NTM species in causing mycobacteriosis in these aquatic animals. The study also revealed the potential of esxA and esxB sequences as markers for phylogenetic classification of mycobacteria. Observations regarding use of esxA and esxB sequences for prediction of potential pathogenicity of mycobacteria warrants further investigation of these two genes in a study employing NTM species with well-defined pathogenicity.

Domestic reptiles as source of zoonotic bacteria: A mini review

Captive reptiles, always more often present in domestic environment as pets, may harbor and excrete a large variety of zoonotic pathogens. Among them, Salmonella is the most well-known agent, whereas there are very scant data about infections by mycobacteria, chlamydiae and leptospirae in cold-blooded animals. However, the investigations that found antibody reactions and/or the bacteria in samples collected from free-ranging and captive reptiles show that herpetofauna may be involved in the epidemiology of these infections. The present review reports the updated knowledge about salmonellosis, mycobacteriosis, chlamydiosis and leptospirosis in reptiles and underlines the risk of infection to which people, mainly children, are exposed.

Mycobacterium haemophilum infection in a juvenile leatherback sea turtle (Dermochelys coriacea)

Mycobacteriosis is infrequently reported in free-ranging sea turtles. Nontuberculous Mycobacterium haemophilum was identified as the causative agent of disseminated mycobacteriosis in a juvenile leatherback turtle (Dermochelys coriacea) that was found stranded on the Atlantic coast of Florida. Disseminated granulomatous inflammation was identified histologically, most notably affecting the nervous system. Identification of mycobacterial infection was based on cytologic, molecular, histologic, and microbiologic methods. Among stranded sea turtles received for diagnostic evaluation from the Atlantic and Gulf of Mexico coasts of the United States between 2004 and 2015, the diagnosis of mycobacteriosis was overrepresented in stranded oceanic-phase juveniles compared with larger size classes, which suggests potential differences in susceptibility or exposure among different life phases in this region. We describe M. haemophilum in a sea turtle, which contributes to the knowledge of diseases of small juvenile sea turtles, an especially cryptic life phase of the leatherback turtle.