Disseminated Mycobacterium avium subspecies infection in a cat

Mycobacterium haemophilum infection in canine cerebrospinal fluid

A 4-year-old female spayed Australian cattle dog was presented to the Emergency Service at the University of Missouri Veterinary Health Center Small Animal Hospital for generalized pain and lethargy. At presentation, the dog showed severe cervical spinal pain and thoracic limb deficits consistent with a multifocal neuroanatomic localization. Magnetic resonance imaging of the cervical spine revealed T2 and T1 postcontrast intense signal extending from the level of the medulla through C5 most marked in the caudal brainstem and cranial cervical spinal cord. The suspected diagnosis was severe meningoencephalomyelitis and secondary edema. Analysis of cerebrospinal fluid (CSF) collected from the cerebellomedullary cistern revealed a marked mixed pleocytosis with intralesional structures morphologically consistent with Mycobacterium sp. Standard DNA PCR assay performed on the CSF yielded the presence of Mycobacterium haemophilum. To the authors' knowledge, this is the first reported case of CNS mycobacteriosis diagnosed on CSF analysis in a dog.

Disseminated Mycobacterium avium infection in a cat on long-term ciclosporin therapy and potential latent infection of an in-contact cat

Case summary

An 8-year-old domestic shorthair cat receiving long-term ciclosporin treatment was evaluated for a history of weight loss and hyporexia. The main clinical finding was a cluster of enlarged mesenteric lymph nodes. Cytological examination of fine-needle aspirates showed granulomatous inflammation with abundant acid-fast bacilli. A diagnosis of Mycobacterium avium complex (MAC) infection was confirmed by PCR. The cat’s clinical condition deteriorated rapidly despite appropriate antibiotic treatment and it was euthanased 2 weeks after initial presentation due to development of severe paraparesis and ataxia. Post-mortem examination revealed granulomatous inflammation affecting multiple lymph nodes and other organs with intrahistiocytic acid-fast bacilli consistent with mycobacteria when stained using Ziehl–Neelsen stain. Another cat in the same household was screened for infection using the interferon gamma release assay (IGRA), with the result being consistent with infection by non-tuberculous mycobacteria (NTM), which includes MAC; however, it had no grossly detectable disease.

Relevance and novel information

This case report is an unusual presentation of disseminated MAC infection in a cat, which remains a rare diagnosis. Clinicians should be aware of unusual and rare presentations of this infection. The clinical findings, progression of disease and histopathology results add to the current clinical database for feline disseminated MAC infections. Another cat in the same household tested positive for NTM by IGRA without any gross disease. This was suggestive of latent MAC infection which, to our knowledge, has not been previously reported in an in-contact cat.

Case Study and Attempt of Treatment of Mycobacteriosis Caused by Mycobacterium avium in a Parental Flock of Meat-Breed Pigeons

Mycobacteriosis caused by Mycobacterium avium subsp. avium was observed in a parental loft of 70 meat-breed pigeons. It was decided to undertake treatment as the birds represented a substantial value to the owner. A multiagent therapy using azithromycin, marbofloxacin, and ethambutol was administered. After 4 mo of therapy, the desired results were not obtained. At the end of treatment, the birds were in poor general condition, with white blood cells above 20 g/L, and after clutching, 2-yr-old and older birds were euthanatized. Overall, postmortem lesions were found in 17 out of 49 necropsied individuals. Slide agglutination tests with a M. avium subsp. avium lysate were conducted in all examined pigeons. In 28 pigeons, blood count was conducted once a month during therapy, while in 24 pigeons, a tuberculin sensitivity test was conducted before the planned euthanatization. The tuberculin sensitivity test did not prove useful in the diagnosis of ill individuals. Slide agglutination yielded positive results in only four birds, all of which also had postmortem lesions. Blood count in a large number of cases allowed distinguishing between ill and healthy individuals, which was used for subsequent selection. The comparison of cultured strains with the (CCG)4-based PCR method showed the variation of M. avium isolates up to a maximum of 30%. The described case proves that the treatment of mycobacteriosis in pigeon flocks is not effective, mainly due to the high resistance to M. avium subsp. avium. In addition, therapy may contribute to an even greater increase in mycobacterial resistance to antibiotics, which may pose a potential risk to public health.

Feline mycobacterial disease in northern California: Epidemiology, clinical features, and antimicrobial susceptibility

BACKGROUND

Mycobacterial infections in cats are challenging to treat and incompletely described.

HYPOTHESIS/OBJECTIVES

To describe the features of mycobacterial infections in cats from northern California.

ANIMALS

Nineteen cats, all with nontuberculous mycobacterial (NTM) infections; 4 with Mycobacterium avium infection, 15 with rapid-growing mycobacterial (RGM) infection.

METHODS

Retrospective study. Cases with positive mycobacterial culture, species identification, and susceptibility testing were included. Descriptive statistics were used. Fisher's exact test and Mann-Whitney U test were used for comparisons between M avium and RGM infections (P ≤ .05).

RESULTS

Rapid-growing mycobacterial cases included Mycobacterium smegmatis (9), Mycobacterium fortuitum (4), Mycobacterium abscessus (1), and Mycobacterium thermoresistibile (1). Mycobacterium avium infections were more likely than RGM infections to be disseminated (3/4 vs 0/15; P = .004). Disease of the skin/subcutis (15/15 vs 0/4; P < .001) and outdoor access (14/15 vs 0/4; P = .001) were primary features of RGM infections. Resistance to fluoroquinolones and aminoglycosides was common among M avium isolates. A high prevalence of resistance to third- and fourth-generation cephalosporins was noted in RGM species. Death/euthanasia was noted only in M avium cases (3/4). Twelve of 15 cats with RGM infection had available follow-up; 4 of these cats achieved remission.

CONCLUSIONS AND CLINICAL IMPORTANCE

The most prevalent RGM species isolated from cats from northern California are M smegmatis and M fortuitum. Susceptibility to prescribed antimicrobials does not appear to guarantee treatment success. Combination drug treatment is recommended. Repeat culture and susceptibility testing should be performed when disease is persistent/relapsing.

Reversible myelosuppression suspected to be secondary to linezolid in a cat with infected subcutaneous ureteral bypass systems

CASE SUMMARY

A 5-year-old castrated male domestic shorthair cat was presented for a multidrug-resistant Enterococcus faecium urinary tract infection within its bilateral subcutaneous ureteral bypass systems. After considerable consultation, the cat was treated with oral linezolid (10 mg/kg q12h) for two separate 2-week courses over 5 weeks. Over this time period, the cat became progressively neutropenic and thrombocytopenic, but was otherwise clinically stable. Upon cessation of the linezolid, the bicytopenia resolved within 12 days.

RELEVANCE AND NOVEL INFORMATION

The reversible myelosuppression in this case is suspected to be secondary to linezolid administration. While previously reported in people, this effect has not been reported at therapeutic doses in veterinary species. This report demonstrates the potential for adverse drug reaction development in cats treated with prolonged linezolid therapy and highlights the need for extreme caution when utilizing linezolid in patients with renal insufficiency. Linezolid is the only drug currently approved by the Food and Drug Administration to treat vancomycin-resistant enterococci infections in people; however, resistance to this antibiotic appears to be increasing. Multidrug-resistant organisms continue to be a real global public health threat in both human and veterinary medicine. Third-tier antibiotics should only be considered under extreme circumstances and after considerable consultation with a specialist. Please note that the authors of this manuscript followed American Veterinary Medical Association policies on stewardship and International Society for Companion Animal Infectious Diseases guidelines, and do not promote or encourage the use in daily practice.

Disseminated nontuberculous mycobacterial disease in a cat caused by Mycobacterium sp. strain MFM001

Mycobacterium sp. strain MFM001 (MFM001), a new strain of slow-growing nontuberculous mycobacteria not associated with the Mycobacterium avium complex, led to disseminated mycobacterial disease characterized by transmural granulomatous gastroenterocolitis of lepromatous type in a cat treated with immunosuppressive medication. MFM001 was found to be closely related to M. kyorinense or M. celatum by partial sequence of 16S rDNA, and identical with an unspecified M. sp. strain B10-07.09.0206 isolated from a human pulmonary infection in Germany. MFM001 should be considered as a pathogenic organism in cats, especially in immunocompromised animals.

Non-tuberculous Mycobacteria can Cause Disseminated Mycobacteriosis in Cats

Mycobacteriosis caused by non-tuberculous mycobacteria (NTM) is a rising concern in human medicine both in immunocompromised and immunocompetent patients. In cats, mycobacteriosis caused by NTM is considered mostly to be a focal or dermal infection, with disseminated disease mostly caused by Mycobacterium avium. We describe three cases of disseminated mycobacteriosis in cats, caused by Mycobacterium malmoense, Mycobacterium branderi/shimoidei and M. avium, with no identified underlying immunosuppression. In all cases, extracellular mycobacteria were seen in the pulmonary epithelium, intestinal lumen and glomerular tufts, which could affect the shedding of the organism. The present study highlights the importance of mycobacteriosis as a differential even in immunocompetent animals. Considering the close relationship of owners and pets and the potential presence of free mycobacteria in secretions, cats should be considered as a possible environmental reservoir for mycobacteria.

Mycobacterium avium subsp. hominissuis menigoencephalitis in a cat

A 33-month old, neutered female Abyssinian cat died. The cat had sudden onset of widespread neurologic signs about half a year after birth. Mycobacterium avium subsp. hominissuis (MAH) group was isolated and identified from the brain of a cat affected with pyogranulomatous meningoencephalitis. The central nervous system (CNS) was involved in the disseminated MAH infection. MAH infection should be considered in cats with neurologic signs in regard to zoonotic aspects. Comparatively, this is a first case of MAH infection observed in the brain in either humans or animals.

Something old, something new: Update of the 2009 and 2013 ABCD guidelines on prevention and management of feline infectious diseases

OVERVIEW

The ABCD has published 34 guidelines in two Special Issues of the Journal of Feline Medicine and Surgery (JFMS): the first in July 2009 (Volume 11, Issue 7, pages 527-620) and the second in July 2013 (Volume 15, Issue 7, pages 528-652). The present article contains updates and new information on 18 of these (17 disease guidelines and one special article 'Prevention of infectious diseases in cat shelters'). For detailed information, readers are referred to the guidelines published in the above-mentioned JFMS Special Issues.

A mycobacterial coinfection in a dog suspected on blood smear

A 4-year-old neutered female crossbred Shepherd was referred for a history of 10 days of anorexia, polyuria, polydipsia, polyadenomegaly, and diarrhea. On physical examination, the dog appeared quiet, responsive, and apyretic, with generalized and severe lymphadenomegaly. Hematologic abnormalities included neutrophilic leukocytosis with left shift, and lymphopenia. Blood smears revealed intracytoplasmic bacilli negatively stained with May-Grünwald-Giemsa in neutrophils and monocytes. Lymph node smears revealed pyogranulomatous adenitis with calcified deposits and many negative-staining rod structures, both within the cytoplasm of neutrophils and macrophages, and free in the background. An acid-fast stain (Ziehl-Neelsen) confirmed the diagnosis of mycobacterial infection. The dog was euthanized for public health and ethical reasons, and the postmortem examination revealed severe and generalized granulomatous and necrotizing lymphadenitis, panniculitis, and hepatitis, and infiltration of epithelioid macrophages in the lungs, colon, and spleen. Numerous acid-fast bacilli, consistent with mycobacterial infection, were observed both in the cytoplasm of epithelioid macrophages and giant cells, and free in the background. Mycobacterium bovis was first confirmed by conventional PCR of organ extracts. Mycobacterium avium was detected in a culture of the same organs. Further PCR amplifications and sequencing revealed a coinfection with 2 different species of mycobacterium, one belonging to the Mycobacterium avium complex and the other to the Mycobacterium tuberculosis complex.

First description of Mycobacterium heckeshornense infection in a feline immunodeficiency virus-positive cat

A 13-year-old cat was presented to the veterinary clinic with poor condition, vomiting and a reduced appetite. A painful abdomen was diagnosed because of tension and defence reactions on palpation. Diagnostic laparotomy showed a thickening of the colon and caecal intestinal wall. Histopathological investigation of intestinal biopsies revealed focal severe granulomatous inflammation with numerous acid-fast bacilli in the tela submucosa. The complete blood count test showed a severe lymphopenia and anaemia, and the cat tested positive for feline immunodeficiency virus (FIV) antibodies by enzyme-linked immunosorbent assay. The cat was euthanased and necropsied. Multifocal granulomatous nodules were present in the intestines, liver and kidneys. The gastric lymph node was markedly enlarged and showed a caseous cut surface. Histopathology revealed a systemic mycobacteriosis affecting intestine, lymph nodes, liver and kidneys. The mycobacterial strain was cultured and determined by its unique 16S rRNA gene sequence as Mycobacterium heckeshornense. This is the first reported case of M heckeshornense in a cat. It was suspected that the disseminated mycobacteriosis was supported by the FIV infection.

Mycobacterioses in cats: ABCD guidelines on prevention and management

OVERVIEW

Mycobacterial infections are important in humans and animals. Cats can be infected by several Mycobacterium species, which may cause different syndromes, mainly tuberculosis, atypical or non-tuberculous mycobacteriosis and leprosy. In recent years, awareness has increased about how to recognise and confirm these infections. More cases are diagnosed today, which probably means that the disease has escaped detection in the past.

INFECTION

Most cases in cats are cutaneous, presenting as nodules in the skin and draining tracts, ulceration and local lymphadenopathy; however, systemic dissemination may also occur.

DIAGNOSIS

Definitive diagnosis is difficult when the bacterium cannot be detected by histology or culture. However, species confirmation is essential for treatment and prognosis, so material for culture and polymerase chain reaction should be submitted in every suspected case.

TREATMENT

Treatment is challenging. A combination of two or three antibiotics is needed, and treatment must be continued for some months, which makes owner compliance especially difficult in cats. ZOONOTIC RISK: There is a zoonotic risk associated with some mycobacterial species. Concerns should be communicated in every case of an immunocompromised owner in contact with an infected cat.

Mechanisms, causes, investigation and management of vomiting disorders in cats: a literature review

Vomiting is a common presenting complaint in feline practice. This article differs from previous reviews in that it is an evidence-based review of the mechanisms, causes, investigation and management of vomiting in the domestic cat. Published evidence was reviewed, and then used to make recommendations for clinical assessment, diagnosis, antiemetic drug treatment, dietary management and monitoring of cats presenting with vomiting. The strength of the evidence on which recommendations are made (and areas where evidence is lacking for cats) has been highlighted throughout.

Mycobacterial disease in cats in Great Britain: I. Culture results, geographical distribution and clinical presentation of 339 cases

This study investigated 339 cases of feline mycobacterial disease from cats with cutaneous lesions or masses found at exploratory laparotomy. Tissue samples were submitted to the Veterinary Laboratories Agency for mycobacterial culture over a 4-year period to December 2008. The study assessed which species of culturable mycobacteria were involved, where the cats lived, and their clinical presentation (physical findings, serum biochemistry, radiography, feline leukaemia virus and feline immunodeficiency virus status). Mycobacterium microti was cultured from 19%, Mycobacterium bovis 15%, Mycobacterium avium 7%, non-M avium non-tuberculous mycobacteria 6%, with no growth in 53% of samples. M microti, M bovis and M avium were found in almost mutually exclusive clusters within Great Britain (GB) (ie, M bovis in South-West England/Wales/Welsh Border, M avium in eastern England and M microti south of London and in South-West Scotland). While differences were seen in the clinical presentation and distribution of lesions caused by the different infections, these were not sufficiently different to be diagnostic. Cats commonly presented with single or multiple cutaneous lesions (74%), which were sometimes ulcerated or discharging, located most frequently on the head (54%). Lymph nodes were usually involved (47%); typically the submandibular nodes. Systemic or pulmonary signs were rarely seen (10-16%). When a cat is suspected of having mycobacteriosis, accurate identification of the species involved helps to determine appropriate action. Our findings show that knowing the cat's geographic location can be helpful, while the nature of the clinical presentation is less useful. Most cases of feline mycobacterial disease in GB are cutaneous.