MANAGEMENT OF OSTEOMYELITIS CAUSED BY SALMONELLA ENTERICA SUBSP. HOUTENAE IN A TAYLOR'S CANTIL (AGKISTRODON BILINEATUS TAYLORI) USING AMIKACIN DELIVERED VIA OSMOTIC PUMP

The cutaneous microbiota and Nannizziomycosis in bearded dragons (Pogona vitticeps): Associations between infectious Nannizziopsis species and common bacterial pathogens

BACKGROUND

In bearded dragons (Pogona vitticeps), nannizziomycosis can cause skin lesions, ulceration and lethargy. Formally known as yellow fungal disease (YFD), nannizziomycosis has traditionally been attributed to various Nannizziopsis spp. identified via culture and referred to as Chrysosporium anamorph of Nannizziopsis (CANV).

HYPOTHESIS/OBJECTIVES

We hypothesized that the presence of Nannizziopsis does not always lead to nannizziomycosis, and that this disease may be caused by multiple pathogens or interactions between microbes (known as the cross-kingdom effect).

ANIMALS

Thirty-one bearded dragons with suspected nannizziomycosis (unhealthy group) and 20 healthy bearded dragons.

MATERIALS AND METHODS

Next-generation sequencing (NGS) was used to explore the microbial interactions within the cutaneous microbiota of 51 bearded dragons.

RESULTS

One unidentified species within the Nannizziopsis genus (Nannizziopsis sp.) was included in a co-occurrence analysis between 877 bacterial and 78 fungal species in the unhealthy group. Forty-one positive co-occurrences with Nannizziopsis spp. were seen, including Salmonella enterica (p = 0.001), an unidentified species within the Clostridiales order (p < 0.001) and a fungal species from the Cladosporium genus (p = 0.0261). Forty-nine negative interactions with Nannizziopsis spp. were seen, including Bifidobacterium adolescentis (p = 0.0478) and Corynebacterium durum (p = 0.0478).

CONCLUSIONS AND CLINICAL RELEVANCE

These findings suggest that commensal microbes may change in response to counteract Nannizziopsis, while pathogenic microbes may help facilitate it. Further research should clarify microbial interactions in bearded dragons with nannizziomycosis.

Fibrinonecrotic enteritis and orchitis associated with Salmonella enterica subsp houtenae infection in a short-tailed boa (Boa constrictor amarali)

Salmonella enterica subsp houtenae has been recovered from a wide variety of species, including reptiles, and has been linked to important clinical manifestations in snakes and lizards. We describe a case of concomitant fibrinonecrotic enteritis and orchitis associated with S. enterica subsp houtenae infection in a short-tailed boa (Boa constrictor amarali). At necropsy, the mucosa of the large intestine was covered by a focally extensive fibrinonecrotic exudate (diphtheritic pseudomembrane). The left testicle was enlarged, firm and diffusely expanded by a thick fibrinous yellow exudate. Polymerase chain reaction and conclusive antigenic testing indicated that the bacteria isolated from the lesions were S. enterica subsp houtenae, and the virulence genes InvA, slyA, stn and spvC were identified. This report reinforces that, although S. enterica subsp houtenae has been isolated from asymptomatic reptiles, it has the potential to cause life-threatening disease in snakes.

Salmonella in reptiles: a review of occurrence, interactions, shedding and risk factors for human infections

Salmonella are considered a part of the normal reptile gut microbiota, but have also been associated with disease in reptiles. Reptile-associated salmonellosis (RAS) can pose a serious health threat to humans, especially children, and an estimated 6% of human sporadic salmonellosis cases have been attributed to direct or indirect contact with reptiles, although the exact number is not known. Two literature searches were conducted for this review. The first evaluated reports of the prevalence of Salmonella in the intestinal tracts of healthy reptiles. Salmonella were most commonly detected in snakes (56.0% overall), followed by lizards (36.9%) and tortoises (34.2%), with lower detection rates reported for turtles (18.6%) and crocodilians (9%). Reptiles in captivity were significantly more likely to shed Salmonella than those sampled in the wild. The majority of Salmonella strains described in reptiles belonged to subspecies I (70.3%), followed by subspecies IIIb (29.7%) and subspecies II (19.6%). The second literature search focused on reports of RAS, revealing that the highest number of cases was associated with contact with turtles (35.3%), followed by lizards (27.1%) and snakes (20.0%). Reptiles associated with RAS therefore did not directly reflect prevalence of Salmonella reported in healthy representatives of a given reptile group. Clinical symptoms associated with RAS predominantly involved the gastrointestinal tract, but also included fever, central nervous symptoms, problems with circulation, respiratory symptoms and others. Disease caused by Salmonella in reptiles appears to be dependent on additional factors, including stress, inadequate husbandry and hygiene, and other infectious agents. While it has been suggested that reptile serovars may cause more severe disease than human-derived strains, and some data is available on invasiveness of individual strains in cell culture, limited information is available on potential mechanisms influencing invasiveness and immune evasion in reptiles and in RAS. Strategies to mitigate the spread of Salmonella through reptiles and to reduce RAS focus mostly on education and hygiene, and have often been met with some success, but additional efforts are needed. Many aspects regarding Salmonella in reptiles remain poorly understood, including the mechanisms by which Salmonella persist in reptile hosts without causing disease.

Pathological and Microbiological Findings in Fatal Cases of Salmonellosis in Captive Bothrops Snakes in Southern Brazil

Salmonella spp. are gram-negative commensal bacteria of vertebrates, including reptiles. Infected snakes may be asymptomatic or manifest clinical disease and death, especially after stressful events. Salmonellosis was diagnosed in 10 captive snakes from the Bothrops genus. The most frequent changes were emaciation (8/10), fibrinonecrotic or granulomatous hepatitis (8/9), fibrinonecrotic or granulomatous enterocolitis (8/9), necrotic and heterophilic myocarditis (2/10), fibrinonecrotic or granulomatous pancreatitis (2/5), fibrinoheterophilic osteomyelitis (1/10), fibrinous and pyogranulomatous pericarditis (1/10) and granulomatous splenitis (1/6). Salmonella enterica was isolated from six cases. The subspecies identified were arizonae (3/6), diarizonae (1/6) and houtenae (1/6), in addition to the serotype Typhimurium (1/6). In cases without isolation, there was immunolabelling of Salmonella spp. in intestinal (3/4), hepatic (1/4) and cardiac (1/4) lesions.

Survey of Post-Cranial Skeletal Pathology in Snakes

Previous reports on skeletal pathology in captive snakes did not clarify the relationship of lesions to captive or free-ranging status. In this study, post-cranial skeletons from 7,950 captive and free-ranging snakes in nine of the major North American collections were examined macroscopically, microscopically and radiologically for the presence of pathology. Micro-computerized tomography was performed on two skeletons on which surface microscopy failed to provide a definitive diagnosis. Osteomyelitis was identified in the vertebrae of 24 snakes and spondyloarthropathy in one snake. Neoplasia or congenital anomalies were not found. Osteomyelitis was four times as common in Viperidae than in Colubridae and twice as common as in Boidae, independent of captive or free-ranging status. A lytic lesion in the vertebrae of one snake was suggestive of fungal disease. The progression of bone lesions was greater in captive snakes, but the prevalence was independent of captive or free-ranging status. The results of this study indicate that bone alterations, previously proposed as neoplastic disease, in archival snake skeletons were most likely of infectious aetiology, and establish macroscopic examination as a useful technique for characterizing skeletal pathology in snakes.

Salmonella enterica subspecies houtenae as an opportunistic pathogen in a case of meningoencephalomyelitis and bacteriuria in a dog

Background

We report the first case of canine Salmonella meningoencephalomyelitis and second case of canine Salmonella bacteriuria, as well as the first reported case of Salmonella enterica subspecies houtenae in a dog.

Case presentation

Immunosuppressive treatment in a dog for a relapse of steroid-responsive meningitis and arteritis (SRMA) allowed for the opportunistic establishment of a bacteremia with Salmonella enterica subsp. houtenae, ultimately causing meningoencephalomyelitis and subclinical bacteriuria. The bacterial infections were treated with a four-month course of amoxicillin; clinical treatment success was determined by serial negative urine cultures and lack of clinical signs correlated to the meningoencephalomyelitis.

Conclusions

Both the bacteriuria and meningoencephalomyelitis represented opportunistic infections in a dog immunosuppressed for SRMA. The clinical course of this infectious meningoencephalitis emphasizes the importance of differentiating relapse of initial disease from opportunistic infection occurring in a compromised central nervous system. The novel Salmonella species identified in this case acts as a reminder that infectious disease diagnostics should not be curbed by anecdotal prediction of routine pathogenic suspects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-020-02652-5.

Advances in Therapeutics and Delayed Drug Release

Reducing the frequency of drug administration in the treatment of exotic pets is advantageous because it may decrease handling frequency and thus potential stress and injury risk for the animal, increase owner compliance with the prescribed treatment, and decrease need for general anesthesia in patients that cannot be handled safely. Increasing efficient drug plasma concentration using sustained-released delivery systems is an appealing solution. Potential candidates that could provide a promising solution have been investigated in exotic pets. In this article, the technologies that are the closest to being integrated in exotic pet medicine are reviewed: osmotic pumps, nanoparticles, and hydrogels.

PREVALENCE, INCIDENCE, AND IDENTIFICATION OF SALMONELLA ENTERICA FROM WILD AND CAPTIVE GRAND CAYMAN IGUANAS ( CYCLURA LEWISI)

From 2005 to 2017, a total of 334 fresh fecal samples was obtained from 236 captive and free-ranging Grand Cayman iguanas ( Cyclura lewisi) in a captive breeding and release program. One-hundred-sixteen samples were obtained from individual captive iguanas living in enclosures with natural substrate, 161 samples from captive iguanas living in elevated wire-bottom enclosures, and 57 samples from free-ranging wild iguanas. These samples were cultured to isolate subspecies of Salmonella enterica. as part of prerelease health evaluations, and to determine baseline health assessments of captive and wild populations of these iguanas. There was a 5.45% (95% confidence interval [CI]: 1.14-15.12) prevalence of S. enterica in iguanas housed on natural substrate ( n = 51), 3.85% (CI: 1.42-8.19) in iguanas housed in elevated wire-bottom enclosures ( n = 157), and 6.06% (CI: 0.74-20.23) in wild free-ranging iguanas ( n = 38). These results demonstrate no significant difference ( P = 0.73) in S. enterica prevalence among these housing conditions. The incidence of S. enterica from 2005 to 2017 in the population sampled was 4.19% (CI 3.10-5.29). Ten different serotypes of S. enterica were isolated from 14 iguanas. Salmonella enterica ser. Saintpaul was the most frequent isolate. Annual S. enterica prevalence was calculated for iguanas housed in different enclosure types, for free-roaming wild iguanas, and for all cultured iguanas. The highest yearly prevalence was 23.08% (CI: 5.04-53.81) in iguanas tested in 2007 ( n = 21). No Salmonella enterica were cultured in 2005, 2008, 2009, 2010, 2011, 2012, and 2015. These results suggest that the shedding of S. enterica was not significantly different between housing types or between captive versus wild iguanas and therefore that release of captive iguanas did not significantly affect the health of the wild population or their exposure to S. enterica.

Reptiles in Guadeloupe (French West Indies) are a reservoir of major human Salmonella enterica serovars

The epidemiology of human Salmonella enterica infections in Guadeloupe (French West Indies) appears to be specific, with a higher prevalence of the subspecies enterica serovars Panama and Arechavaleta (Panama and Arechavaleta) than in other regions. A study was performed in Guadeloupe to identify the reservoir of Salmonella serovars by comparing their distribution in warm- and cold-blooded animals and in humans living in Guadeloupe and mainland France. Furthermore, a case-control study was conducted in 2012-2013 to identify the main epidemiologic risk factors for S. enterica infection among children under 15 years of age. Between June 2011 and December 2014, feces from 426 reptiles (322 anoles, 69 iguanas and 35 geckos) and 50 frogs distributed throughout Guadeloupe and nearby islands were investigated. The frequency of S. enterica carriage was 15.0% (n = 64) in reptiles but varied by species. The only significant risk factor for S. enterica infection was a more frequent presence of frogs in the houses of cases than in those of controls (P = 0.042); however, isolates were not collected. Panama and Arechavaleta were the two serovars most often recovered between 2005 and 2014 from humans living in Guadeloupe (24.5% (n = 174) and 11.5% (n = 82), respectively), which is in contrast to the low prevalence in mainland France (0.4%). Their presence at low frequencies in wild reptiles (4.6% (n = 3) and 3.1% (n = 2), respectively) and pigs (7.5% (n = 5) and 1.5% (n = 1), respectively) suggests a broad host range, and humans may be infected by indirect or direct contact with animals. These serovars are probably poorly adapted to humans and therefore cause more severe infections. The unusual subspecies houtenae serovar 43:z4,z32:- was a major subspecies in wild reptiles (24.6%, n = 16) and humans (9.4%, n = 67) but was not recovered from warm-blooded animals, suggesting that reptiles plays a key role in human infection.

Salmonella enterica serovars Panama and Arechavaleta: Risk Factors for Invasive Non-Typhoidal Salmonella Disease in Guadeloupe, French West Indies

A retrospective study was conducted to identify the risk factors associated with Salmonella enterica bacteremia in infants and children in Guadeloupe, French West Indies. The 171 patients with S. enterica infection seen between 2010 and 2014 included 155 (90.6%) with acute gastroenteritis, of whom 42 (27.1%) had concomitant bacteremia, and 16 (9.4%) with primary bacteremia. Most cases (97.7%) were in infants and children with no underlying health condition. Two subspecies were recovered: enterica (N = 161, 94.2%) and houtenae (N = 10, 5.8%). All but one (serovar Typhi) were non-typhoidal Salmonella. The most common serovars were Panama (N = 57, 33.3% of isolates) and Arechavaleta (N = 28, 16.4%). Univariate analysis showed a strong association only between age > 6 months and infection with the Panama or Arechavaleta serovar (P = 0.002). The rate of resistance to all classes of antibiotics during the study period was low (< 15%); however, the detection of one extended-spectrum beta-lactamase-producing S. enterica strain highlights the need for continued monitoring of antimicrobial drug susceptibility. Infection with Panama (P < 0.001) or Arechavaleta (P < 0.001) serovar was significantly associated with bacteremia in a multivariate analysis. These serovars are probably poorly adapted to humans or are more virulent. A delay between onset of symptoms and hospital admission > 5 days (P = 0.01), vomiting (P = 0.001), and increased respiratory rate (P = 0.001) contributed independently to bacteremia in the multivariate analysis. Thus, if non-typhoidal infection is suspected, blood should be cultured and antibiotic treatment initiated in all patients who meet these criteria.

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.