Osteomyelitis in a slaughter turkey flock caused by Yersinia pseudotuberculosis sequence type ST42.

A Yersinia pseudotuberculosis outbreak was diagnosed in a male turkey flock in Finland. Y. pseudotuberculosis is a quite rare zoonotic bacterium, which typically causes enteritis in humans and sudden death in animals. In this study, osteomyelitis was diagnosed in small, lame, 11- to 12-wk-old male turkeys. Lameness and slower growth among the turkeys was observed on the farm. During pathological examination, multiple lesions were found in the metaphyseal and physeal areas of the femurs, tibiotarsi, and tarsometatarsi, with multifocal to coalescing mixed heterophilic/granulomatous necrotizing osteomyelitis. Y. pseudotuberculosis was isolated from the femoral and tibiotarsal bones or from the joints of six lame turkeys sent for necropsy. The isolation required homogenizing of lesion tissue in phosphate-mannitol-peptone broth, which was cultured directly - and, if needed, after cold enrichment - on selective cefsulodin-irgasan-novobiocin agar. Whole-genome sequencing was used for identification and typing. All isolates belonged to bio/serotype 1/O:1a and sequence type ST42 (Achtman scheme), which is commonly reported in both human and animal Y. pseudotuberculosis infections in Europe. The isolates from all six turkeys showed only one to two allele differences in the core genome comparison, indicating a common source of infection. All asymptomatic turkeys were slaughtered at the age of 17 weeks. Whole and partial carcass condemnation rates at the slaughterhouse were high, but no macroscopic changes in the skeletal system were found, showing that food chain information is essential. This study confirms earlier findings that Y. pseudotuberculosis can cause osteomyelitis in fattening turkeys, leading to lameness. Food chain information is essential for slaughterhouse operations, to protect the workers and emphasize good working hygiene during slaughter.

Outbreak in African lions of Yersinia pseudotuberculosis infection, with aberrant bacterial morphology.

A concurrent outbreak of infection with Yersinia pseudotuberculosis occurred in adult captive African lions (Panthera leo). Two 17-y-old male lions and one 14-y-old female lion developed respiratory distress, lethargy, ataxia, and hyporexia. Within 3-5 d of the onset of clinical signs, one male and the female lion died and were submitted for postmortem examination. Macroscopically, the liver and spleen had multifocal-to-coalescing, semi-firm, pale-tan nodules throughout the parenchyma. The lungs were non-collapsed and marked by petechiae. Histologic examination identified lytic, necrosuppurative foci in the liver, spleen, lungs, and kidney, with abundant intralesional gram-negative coccobacilli in the male lion. Similar findings were seen in the female lion in the liver, spleen, kidney, and mesenteric lymph node; however, the intralesional bacterial colonies were more pleomorphic, comprising rod and filamentous morphologies. Aerobic bacterial culture of the liver, spleen, and lung revealed Y. pseudotuberculosis growth. The source of infection is unknown, and an epidemiologic study was performed. Sources to be considered are from the predation of rodent and/or bird reservoirs, or contaminated soil or water. Mortality associated with Y. pseudotuberculosis has been described in an African lion cub, however, to our knowledge, Y. pseudotuberculosis has not been reported in adult African lions, and this is only the second report of Y. pseudotuberculosis with aberrant bacterial morphology observed histologically.

Analysis of Yersinia pseudotuberculosis Isolates Recovered from Deceased Mammals of a German Zoo Animal Collection.

Yersinia pseudotuberculosis is an important pathogen for both humans and animals. It can infect livestock, as well as pets and wild animals. During recent years, a number of reports have described the isolation of Y. pseudotuberculosis from zoo animals, mainly birds and mammals, for which the infection was mostly lethal. Between 2005 and 2019, there were at least 17 cases of deceased mammals, belonging to five different species, which suffered from a Y. pseudotuberculosis infection at the Zoo Wuppertal, Germany. Since only scarce information exists on the properties of Y. pseudotuberculosis from zoo animals, we characterized eight isolates, covering all infected species, in detail. All isolates were members of biotype 1, but belonged to five serotypes, five sequence types (STs), and seven core-genome multilocus sequence types (cgMLSTs). Using pulsed-field gel electrophoresis (PFGE) analysis and whole-genome sequencing (WGS), the seven isolates could be discriminated from each other. They differed significantly regarding their virulence genes and mobile genetic elements. While the virulence plasmid pYV existed in all serotypes (five isolates), a complete high-pathogenicity island (HPI) was detected only in the serotypes O:1a, O:1b, and O:13 (four isolates), but not in O:2a and O:2b. Similarly, the content of other plasmids and prophages varied greatly between the isolates. The data demonstrate that the deceased mammals were infected by seven individual isolates and not by a single type predominating in the zoo animals.

Yersinia pseudotuberculosis serotype O:1 infection in a captive Seba's short tailed-fruit bat (Carollia perspicillata) colony in Switzerland.

BACKGROUND: Between February and April 2016, a slight increase in mortality was observed in a colony consisting of 400 captive Seba's short-tailed bats (Carollia perspicillata). These animals cohabited with other nocturnal animal species in a dome of a private zoo in Switzerland. RESULTS: Gross and histological analysis of two (14.3%) out of the 13 animals submitted for necropsy within this period revealed a necrosuppurative pneumonia, hepatitis, splenitis, enterocolitis, and endometritis, with abundant intralesional colonies of Gram-negative rods. Yersinia (Y.) pseudotuberculosis serotype O:1 and biotype 1 belonging to the sequence type ST90 was isolated from the affected organs in both animals. Following this diagnosis, » of the colony (99 animals) was culled and submitted for gross and histopathological analysis, and a bacterial culture selective for Yersinia spp. of lung, liver, and spleen was performed. From these 99 animals, one gravid female was tested and found to be positive for Y. pseudotuberculosis in the absence of clinical symptoms and histopathological lesions. PCR analysis of altogether three bacterial isolates for virulence factors revealed the presence of the ail gene, and one isolate was also positive for the virF and yadA plasmid genes. CONCLUSIONS: These findings suggest that Carollia perspicillata are susceptible to lethal yersiniosis but do not represent a regular reservoir for Y. pseudotuberculosis. Culling of » of the population was sufficient to limit the spread of this infection among the colony. Moreover, no infections were detected in cohabitant nocturnal animals and caretakers, indicating that the zoonotic risk in this case was low.

YERSINIA PSEUDOTUBERCULOSIS INFECTIONS IN PRIMATES, ARTIODACTYLS, AND BIRDS WITHIN A ZOOLOGICAL FACILITY IN THE UNITED KINGDOM.

Infection with Yersinia pseudotuberculosis can be difficult to diagnose and treat successfully. Twenty-four cases from the Zoological Society of London (ZSL) London Zoo and ZSL Whipsnade Zoo were identified between 2001 and 2019. Husbandry, medical, and postmortem records for six primates, 10 artiodactyls, and eight birds were reviewed to identify common clinical signs and gross lesions. Most cases occurred during the winter; however, an outbreak in four primates occurred during the summer following a period of stress associated with increased ambient noise and activity. Common clinical signs included lethargy (6/6 primates, 4/10 artiodactyls, 4/8 birds) or death without premonitory signs (3/10 artiodactyls, 4/8 birds). Once clinical signs were observed, disease progressed quickly. Poor condition was common in mammals (6/6 primates, 9/10 artiodactyls), but often went undetected until postmortem examination. Neurological signs occurred in three of six primates. Diarrhea and anorexia were uncommon in all animals. Hepatitis was observed in all groups (4/6 primates, 2/10 artiodactyls, 4/8 birds), mesenteric lymphadenomegaly was common in mammals (4/6 primates, 8/10 artiodactyls), and gastroenteritis was common in artiodactyls (7/10). Erythematous, punctate rashes, which have only been reported with yersiniosis in humans, were present in three of six primates. Bacterial cultures from the liver in primates and birds or enlarged mesenteric lymph nodes in artiodactyls were often diagnostic. All isolates were susceptible to marbofloxacin, oxytetracycline, streptomycin, ceftazidime, amoxicillin clavulanic acid, trimethoprim sulfamethoxazole, azithromycin, and doxycycline, and resistant to clindamycin. Histopathology and Perl's Prussian blue stains were performed on available liver samples (n = 18). Intracellular hemosiderin was present in 17 of 18 cases. Additional research is needed to determine if there is a relationship between hemosiderosis and yersiniosis.

Measurement of Yersinia Translocon Pore Formation in Erythrocytes.

Many Gram-negative pathogens produce a type III secretion system capable of intoxicating eukaryotic cells with immune-modulating effector proteins. Fundamental to this injection process is the prior secretion of two translocator proteins destined for injectisome translocon pore assembly within the host cell plasma membrane. It is through this pore that effectors are believed to travel to gain access to the host cell interior. Yersinia species especially pathogenic to humans and animals assemble this translocon pore utilizing two hydrophobic translocator proteins-YopB and YopD. Although a full molecular understanding of the biogenesis, function and regulation of this translocon pore and subsequent effector delivery into host cells remains elusive, some of what we know about these processes can be attributed to studies of bacterial infections of erythrocytes. Herein we describe the methodology of erythrocyte infections by Yersinia, and how analysis of the resultant contact-dependent hemolysis can serve as a relative measurement of YopB- and YopD-dependent translocon pore formation.

Assessment of the efficacy of an autogenous vaccine against Yersinia pseudotuberculosis in young Merino sheep.

AIMS To assess the efficacy of an autogenous vaccine against Yersinia pseudotuberculosis III in preventing clinical disease and deaths due to yersiniosis in young Merino sheep, and to determine the effect of vaccination on the prevalence of faecal shedding of pathogenic Yersinia spp., daily liveweight gain, and development of antibodies to Yersinia spp. following vaccination and natural exposure. METHODS In six groups (three groups each from two farms) of young Merino sheep, 148-150 animals were systematically allocated to be vaccinated twice with an autogenous, formalin- killed bacterin vaccine containing Y. pseudotuberculosis serotype III or to remain non-vaccinated. All vaccinated and non-vaccinated sheep were run together in their original groups throughout the trial. Faecal and blood samples were collected, and liveweight measured, at the time of vaccination and subsequently over a 6-month period to determine faecal shedding of Y. enterocolitica and Y. pseudotuberculosis, seroprevalence of antibodies to Yersinia outer membrane proteins (YOP) and changes in liveweight. RESULTS None of the six trial groups experienced an outbreak of clinical yersiniosis during the study period. On Farm A, the prevalence of shedding of either or both Yersinia spp. was <40% on all but one sampling occasions. On Farm B the prevalence of shedding of both Yersinia spp. peaked at 98%, 96 days after vaccination. Mean liveweight and daily liveweight gain at the end of the study were similar in vaccinated and non-vaccinated groups on both farms (p>0.1), as was the prevalence of faecal shedding of Yersinia spp. (p>0.2), and the proportion of animals that became seropositive for antibodies to YOP following vaccination (p>0.1). CONCLUSIONS AND CLINICAL RELEVANCE This vaccine had, at most, limited effects on seroconversion and, under the conditions of this study, had no demonstrable impact on liveweight, mean daily liveweight gain or faecal shedding of Yersinia spp. Further studies are needed to determine the efficacy of this vaccine during outbreaks of yersiniosis or following experimental challenge with pathogenic Yersinia spp..

Systemic Yersinia pseudotuberculosis as a Cause of Osteomyelitis in a Captive Ring-tailed Lemur (Lemur catta).

Yersinia pseudotuberculosis and Yersinia enterocolitica are ubiquitous pathogens with wildlife and domestic animal reservoirs. Outbreaks of 'non-plague' yersiniosis in man and non-human primates are reported frequently (including zoological specimens and research breeding colonies) and are usually characterized by enteritis, mesenteric lymphadenitis and occasionally organ abscessation. In people, non-septic reactive arthritis is a common sequela to yersiniosis. However, there have been rare reports in people of septic arthritis and osteomyelitis because of active systemic infection with Y. pseudotuberculosis. Osteomyelitis has also been reported rarely in historical yersiniosis outbreaks in farmed turkeys in England and the USA. This paper reports the first case of osteomyelitis caused by systemic infection with Y. pseudotuberculosis O:1 in a non-human primate, a captive ring-tailed lemur (Lemur catta). The lemur had a short clinical history of hyporexia and weight loss with reduction in mobility, especially of the left hindlimb. On post-mortem examination there was evidence of multi-organ abscessation. In addition, severe necrosis, inflammation and large bacterial colonies were present in the musculature, periosteum and bone marrow in the hip, ribs and a vertebra at the cervicothoracic junction. Osteomyelitis should be considered as a rare clinical presentation in non-human primates with systemic Y. pseudotuberculosis infection.

Distribution of enteropathogenic Yersinia spp. and Salmonella spp. in the Swedish wild boar population, and assessment of risk factors that may affect their prevalence.

BACKGROUND: Pure Eurasian wild boars and/or hybrids with domestic pigs are present in the wild on most continents. These wild pigs have been demonstrated to carry a large number of zoonotic and epizootic pathogens such as Salmonella spp., Yersinia enterocolitica and Y. pseudotuberculosis. Wild boar populations throughout Europe are growing and more and more wild boar meat is being consumed, the majority within the homes of hunters without having passed a veterinary inspection. The aim of this study was to investigate if factors such as population density, level of artificial feeding, time since establishment of a given population, and the handling of animal by-products from slaughtered animals could influence the presence of these pathogens in the wild boar. RESULTS: In total, 90 wild boars from 30 different populations in Sweden were sampled and analysed using a protocol combining pre-cultivation and PCR-detection. The results showed that 27% of the sampled wild boars were positive for Salmonella spp., 31% were positive for Y. enterocolitica and 22% were positive for Y. pseudotuberculosis. In 80% of the sampled populations, at least one wild boar was positive for one of these enteropathogens and in total, 60% of the animals carried at least one of the investigated enteropathogens. The presumptive risk factors were analysed using a case-control approach, however, no significant associations were found. CONCLUSION: Human enteropathogens are commonly carried by wild boars, mainly in the tonsils, and can thus constitute a risk for contamination of the carcass and meat during slaughter. Based on the present results, the effect of reducing population densities and number of artificial feeding places might be limited.

Yersinia pseudotuberculosis Prevalence and Diversity in Wild Boars in Northeast Germany.

In this study, the prevalence of Yersinia pseudotuberculosis in wild boars in northeast Germany was determined. For that purpose, the tonsils of 503 wild boars were sampled. The presence of Y. pseudotuberculosis was studied by diagnostic PCR. Positive samples were analyzed by cultural detection using a modified cold enrichment protocol. Ten Y. pseudotuberculosis isolates were obtained, which were characterized by biotyping, molecular serotyping, and multilocus sequence typing (MLST). In addition, whole-genome sequences and the antimicrobial susceptibility of the isolates were analyzed. Yersinia pseudotuberculosis was isolated from male and female animals, most of which were younger than 1 year. A prevalence of 2% (10/503) was determined by cultural detection, while 6.4% (32/503) of the animals were positive by PCR. The isolates belonged to the biotypes 1 and 2 and serotypes O:1a (n = 7), O:1b (n = 2), and O:4a (n = 1). MLST analysis revealed three sequence types, ST9, ST23, and ST42. Except one isolate, all isolates revealed a strong resistance to colistin. The relationship of the isolates was studied by whole-genome sequencing demonstrating that they belonged to four clades, exhibiting five different pulsed-field gel electrophoresis (PFGE) restriction patterns and a diverse composition of virulence genes. Six isolates harbored the virulence plasmid pYV. Besides two isolates, all isolates contained ail and inv genes and a complete or incomplete high-pathogenicity island (HPI). None of them possessed a gene for the superantigen YPM. The study shows that various Y. pseudotuberculosis strains exist in wild boars in northeast Germany, which may pose a risk to humans.IMPORTANCEYersinia pseudotuberculosis is a foodborne pathogen whose occurrence is poorly understood. One reason for this situation is the difficulty in isolating the species. The methods developed for the isolation of Yersinia enterocolitica are not well suited for Y. pseudotuberculosis We therefore designed a protocol which enabled the isolation of Y. pseudotuberculosis from a relatively high proportion of PCR-positive wild boar tonsils. The study indicates that wild boars in northeast Germany may carry a variety of Y. pseudotuberculosis strains, which differ in terms of their pathogenic potential and other properties. Since wild boars are widely distributed in German forests and even populate cities such as Berlin, they may transmit yersiniae to other animals and crop plants and may thus cause human infections through the consumption of contaminated food. Therefore, the prevalence of Y. pseudotuberculosis should be determined also in other animals and regions to learn more about the natural reservoir of this species.

A study on the efficacy of the recombinant Yersinia adhesin A vaccine against yersiniosis in the early phase.

Yersinia pseudotuberculosis (Y. ptb) is a zoonotic pathogenic bacterial species of the family Enterobacteriaceae and causes yersiniosis, an acute intestinal infection in humans and animals. Y. ptb is often implicated in lethal epidemics in zoo animals and reductions in the breeding population, but a valid prevention method has not been established. Therefore, this study aimed to develop a vaccine for yersiniosis control. The immunogenicity of one of the adhesion factors involved in pathogenic mechanisms of Y. ptb, Yersinia adhesin A (YadA), was investigated. BALB/c mice were divided into 3 groups: in group 1, mice received insoluble recombinant YadA (rYadA) produced in genetically engineered Escherichia coli (100 µg/dose); in group 2, mice received inactivated Y. ptb with strong expression of YadA (20 mg/dose);and in group 3, mice received phosphate-buffered saline (0.2 ml/dose). All interventions were administered subcutaneously twice at an interval of 1 week. One week after the second administration, Y. ptb (107 cells/mouse) was inoculated orally. As a result, the survival rate was 100% in group 1, 60% in group 2, and 0% in group 3. The anti-YadA antibody titer increased in a stepwise fashion in groups 1 and 2. The present study results suggest that rYadA shows promise as a protective antigen against yersiniosis. This study concluded that vaccination against Y. ptb may become available as a new method to prevent lethal epidemics in animals.

Mortality in Captive Rhesus Monkeys (Macaca mulatta) in China Due to Infection with Yersinia pseudotuberculosis Serotype O:1a.

The most common serotypes of Yersinia pseudotuberculosis infecting non-human primates are serotypes O:1b, O:3, O:4, and O:7. The O:1a serotype has never been reported in non-human primates. The present study describes an outbreak of serotype O:1a with high fatality (6/18) in captive rhesus monkeys in China. Bacteria were isolated from different organs of the carcasses using standard microbiological procedures. The strain was identified using conventional and molecular techniques such as morphological and biochemical identification, serotype determination, PCR-sequence analysis based on the 16S rRNA gene, detection of virulence genes, and antimicrobial susceptibility testing. The pathogenicity was determined after experimental infection in mice. Taken together, the obtained data indicate that Y. pseudotuberculosis O:1a is a pathogen of concern and represents a potential threat to monkey conservation efforts.

Yersinia pseudotuberculosis in Eurasian Collared Doves (Streptopelia decaocto) and Retrospective Study of Avian Yersiniosis at the California Animal Health and Food Safety Laboratory System (1990-2015).

In February 2015, two Eurasian collared doves (Streptopelia decaocto) were submitted dead to the California Animal Health and Food Safety (CAHFS) Laboratory, Turlock branch, from a private aviary experiencing sudden, high mortality (4/9) in adult doves. In both doves, the gross and histologic lesions were indicative of acute, fatal septicemia. Grossly, there were numerous pale yellow foci, 1 to 2 mm in diameter, in the liver and spleen. Microscopically, these foci were composed of acute severe multifocal coagulative necrosis of hepatocytes and splenic pulp with infiltration of heterophils mixed with fibrin and dense colonies of gram-negative bacteria. Yersinia pseudotuberculosis was isolated from the lung, liver, spleen, heart, ovary, kidney, and trachea. The organism was susceptible to most antibiotics it was tested against, except erythromycin. Based on a retrospective study of necropsy submissions to CAHFS between 1990 and 2015, there were 77 avian case submissions of Y. pseudotuberculosis. There were 75/77 cases identified from a wide range of captive avian species from both zoo and private facilities and 2/77 cases from two backyard turkeys submitted from one premise. The largest number of cases originated from psittacine species (31/77). The lesions most commonly described were hepatitis (63/77), splenitis (49/77), pneumonia (30/77), nephritis (16/77), and enteritis (12/77). From 1990 to 2015, there was an average of three cases of avian pseudotuberculosis per year at CAHFS. Although there were no cases diagnosed in 1993 and 1994, in all other years, there were between one and eight cases of Y. pseudotuberculosis detected from avian diagnostic submissions.

Prevalence of Yersinia enterocolitica and Yersinia pseudotuberculosis in wild boars in the Basque Country, northern Spain.

BACKGROUND: Yersiniosis is a zoonosis widely distributed in Europe and swine carry different serotypes of Yersinia enterocolitica and Y. pseudotuberculosis. The aim of this study was to determine the prevalence of Y. enterocolitica and Y. pseudotuberculosis in wild boars in northern Spain. The blood of wild boars (n = 505) was sampled between 2001 and 2012. Seroprevalence was determined in 490 serum samples with an indirect enzyme-linked immunosorbent assay. Seventy-two of the animals were also examined for the presence of Y. enterocolitica or Y. pseudotuberculosis in the tonsils with real-time polymerase chain reaction. All the tonsils were analysed twice, directly and after cold enrichment in phosphate-buffered saline supplemented with 1 % mannitol and 0.15 % bile salts. RESULTS: Antibodies directed against Y. enterocolitica and Y. pseudotuberculosis were detected in 52.5 % of the animals. Yersinia enterocolitica was detected with real-time polymerase chain reaction in 33.3 % of the wild boars and Y. pseudotuberculosis in 25 %. Significant differences were observed according to the sampling year, and the highest prevalence was during winter and spring. The highest antibody levels and Y. enterocolitica prevalence were observed in mountainous areas at altitudes higher than 600 m, with very cold winters, and with the highest annual rainfall for each dominant climate. Areas with low and medium livestock populations were associated with the highest seroprevalence of Yersinia spp. in wild boars, whereas areas with high ovine populations had the highest prevalence of Y. enterocolitica. CONCLUSIONS: This study shows that Y. enterocolitica and Y. pseudotuberculosis are highly prevalent among wild boars in the Basque country, with Y. enterocolitica most prevalent. The risk of infection among wild boars is influenced by the season and the area in which they live.

Yersiniosis caused by Yersinia pseudotuberculosis in captive toucans (Ramphastidae) and a Japanese squirrel (Sciurus lis) in zoological gardens in Japan.

Two captive Keel-billed toucans and a Chestnut-mandibled toucan in another zoological garden died suddenly without any pre-existing symptoms, and three months later, a Japanese squirrel died of diarrhea. All these animals showed necrotic enteritis and multifocal necrosis in the liver and spleen with Gram negative bacilli. The bacilli showed strong positive immunolabeling for Yersinia pseudotuberculosis O4 in the Keel-billed toucans, Y. pseudotuberculosis O2 in the Chestnut-mandibled toucan and Y. pseudotuberculosis O1 in the Japanese squirrel, while Y. pseudotuberculosis 4b, 2b and 1b were respectively isolated from the lesions. To our knowledge, this might be the first reported case of fatal yersiniosis in a Japanese squirrel in the world as well as in toucans in Japan.

Yersiniosis due to infection by Yersinia pseudotuberculosis 4b in captive meerkats (Suricata suricatta) in Japan.

Two meerkats (Suricata suricatta) housed in the same zoological garden in Japan died due to Yersinia pseudotuberculosis serotype 4b infection. Gross and microscopic lesions included necrotizing enteritis and enlargement of the spleen and liver with multifocal necrosis. Inflammatory cells, primarily neutrophils, and nuclear debris were associated with clusters of Gram-negative bacilli. Additionally, there were aberrant organism forms that were larger than bacilli and appeared as basophilic globular bodies. Immunohistochemical examination showed that the bacilli and globular bodies were strongly positive for Y. pseudotuberculosis O4 antigen. The globular bodies were considered a shape-changed form of Y. pseudotuberculosis, and these morphologically abnormal bacteria could present a diagnostic challenge.

Disseminated Yersinia pseudotuberculosis infection in a paca (Cuniculus paca).

A 2-yr-old paca (Cuniculus paca) was presented for necropsy with a history of sudden death. GrosS examination revealed multifocal, transmural, well-demarcated, white, soft nodules scattered along the length of the small intestine. The liver also had similar nodules associated with the capsular and cut surface. Histologic evaluation of several organs, including the intestine, liver, lung, kidney, adrenal gland, and lymph nodes, was consistent with disseminated yersiniosis. In addition, aerobic bacterial culture of liver and lung tissue yielded heavy growth of Yersinia pseudotuberculosis. Yersinia pseudotuberculosis is a Gram-negative, enteric pathogen that can cause disease in a variety of terrestrial species including humans. Although systemic infection has been observed in rodent species, to our knowledge this is the first report of disseminated Y pseudotuberculosis in a paca.

Aberrant forms of Yersinia pseudotuberculosis as spheroplasts and filaments in yersiniosis in squirrel monkeys.

This report describes atypical cases of yersiniosis in squirrel monkeys in which aberrant forms of Yersinia pseudotuberculosis were seen. There were 2 outbreaks due to yersiniosis in squirrel monkeys in Japan. The monkeys had systemic necrotizing and hemorrhagic lesions with Gram-negative rod-shaped bacilli and microthromboembolism in the kidneys. Some lesions contained filaments, globular bodies, and other pleomorphic forms of bacteria. All forms were usually seen in the same lesions, and those with pleomorphic morphology appeared to be an intermediate form between the rod-shaped bacteria and the filaments or globular bodies. In addition, they had strong immunolabeling for Y. pseudotuberculosis, as did the rod-shaped bacteria. Therefore, the globular bodies, filaments, and others are strongly suspected to be shape-changed bacilli of Y. pseudotuberculosis. These morphologically altered bacteria could cause errors in diagnosis since they resemble fungi or protozoa, and special staining techniques, including immunohistochemistry, can be helpful in establishing the correct diagnosis.

Atypical Yersinia pseudotuberculosis serotype O:3 isolated from hunted wild boars in Italy.

Atypical Yersinia pseudotuberculosis serotype O:3 was isolated from rectal contents of two wild boars hunted in Italy within a regional wildlife management program. No outbreak of yersiniosis was reported in this area in the same period and no lesions were found by the veterinarian at post-mortem inspection. Nevertheless, after histological examination, granulomatous lesions were detected in submandibular lymph nodes of one of the two wild boars. Microbiological and bio molecular characterization of the isolates revealed a melibiose-negative, biotype 2, wbyK+O:3 genotype, carrying inv, yop (yopH and yopB), virF, and R-HPI. Strains showing the same profile, matching to the criteria of genetic group 5, have been recently reported in fatal cases of yersiniosis in cynomolgus macaques and in farmed deer and atypical O:3 serotype has been suggested as a pathogenic subtype of O:3. This is the third report of an atypical O:3 Y. pseudotuberculosis strain, the first outside the American continent and the first one not associated to fatal yersiniosis. Wild boars could be a possible reservoir of this emerging pathogen.