Causes of morbidity and mortality in wild cottontail rabbits in the eastern United States, 2013-2022.

Interest in causes of mortality of free-ranging, native North American lagomorphs has grown with the emergence of rabbit hemorrhagic disease virus 2 (RHDV2). Over the years 2013-2022, the Southeastern Cooperative Wildlife Disease Study received 119 Sylvilagus spp. case submissions from the central and eastern United States, comprising 147 rabbits. Most (86%) of these submissions occurred after detecting RHDV2 in the United States in 2020. Laboratory data from these rabbits were retrospectively evaluated for major causes, contributors to mortality, and pathogen detections. Gross and histologic examination was performed for 112 rabbits. Common primary causes of death included trauma (n = 49), bacterial disease (n = 31), emaciation (n = 6), and parasitism (n = 6). Among the 32 rabbits with bacterial disease, 12 were diagnosed with tularemia and 7 with pasteurellosis. Rabbits with pasteurellosis had disseminated abscessation, septicemia, and/or polyserositis. Less commonly, cutaneous fibroma (n = 2), notoedric mange (n = 2), encephalitozoonosis (n = 2), neoplasia (round-cell sarcoma; n = 1), and congenital abnormalities (n = 1) were diagnosed. RHDV2 was not detected in 123 rabbits tested. Although RHDV2 has not been detected in wild lagomorphs in the eastern United States, detections in domestic rabbits from the region emphasize the need for continued surveillance. Furthermore, continued surveillance for Francisella tularensis informs public health risk. Overall, increased knowledge of Sylvilagus spp. health furthers our understanding of diseases affecting these important prey and game species.

Diagnosis and Treatment of Gordonia Species Infection in a Peach-Faced Lovebird (Agapornis roseicollis).

Respiratory distress is a common presentation for avian species. A 9-week-old peach-faced lovebird (Agapornis roseicollis) was presented with a 2-week history of progressive dyspnea. Computed tomographic (CT) images were suggestive of splenomegaly and bilateral granulomatous pulmonary disease. Polymerase chain reaction testing of samples from the choana, cloaca, and distal tracheal/syringeal area were positive for Mycobacterium species hsp65. A comparison search of the 400 base pair sequence in the NCBI/BLAST/blastn database revealed a best match of 93% similarity to Gordonia species and 91% similarity to Gordonia bronchialis. Gordonia is a genus in the phylum Actinomycetota, the same lineage that includes Mycobacterium species. Gordonia species can be mistaken for Mycobacterium species unless more definitive diagnostic testing is pursued. Infection caused by Gordonia species is rare in humans. Reports commonly cite infection of immunocompromised patients, and to our knowledge, no reports of treatment have been published in the veterinary literature. After the test results were obtained, the patient was treated with azithromycin and pradofloxacin for 3 months. The lovebird was presented for reexamination when the antibiotic treatment was complete. When reexamined, and a second series of CT images evaluated, it was determined that the treatment achieved clinical resolution of signs and lesions.

Listeriosis with viral coinfections in 8 gray foxes, 8 wild turkeys, and 2 young cervids in the southeastern United States.

Listeria monocytogenes is a bacterium that can cause disease in many species, including humans, livestock, and wildlife. Increased interactions via shared habitats may promote pathogen transmission among these groups. Our objectives were to evaluate the Southeastern Cooperative Wildlife Disease Study diagnostic data to characterize and compare L. monocytogenes-induced lesions and comorbidities in gray foxes and wild turkeys, and to describe cases of listeriosis in 2 cervids. From 1991-2020, 8 gray foxes, 8 wild turkeys, a neonatal elk, and a white-tailed deer fawn from several eastern states in the United States were diagnosed with listeriosis. All 8 foxes had hepatitis and/or hepatic necrosis with intralesional gram-positive bacilli, and concurrent canine distemper virus (CDV) infection; 2 of the foxes had been vaccinated recently for CDV. L. monocytogenes was cultured from the liver (6 of 8) or lung (2 of 8) of foxes. Lesions in wild turkeys included hepatocellular necrosis (3 of 8), heterophilic hepatitis (1 of 8), heterophilic granulomas (1 of 8), intrasinusoidal gram-positive bacilli without hepatic lesions (1 of 8), granulomatous dermatitis (1 of 8), and/or granulomatous myocarditis (2 of 8). Lymphoproliferative disease viral DNA was detected in 5 of 6 turkeys tested; reticuloendotheliosis viral DNA was detected in 2 of 3 turkeys tested. Both cervids had systemic listeriosis, with L. monocytogenes isolated from liver. Immunohistochemistry for Listeria spp. on select cases revealed immunolabeling in affected organs. Listeriosis was thus established as a cause of morbidity and mortality in 3 wildlife species, which often suffered from concurrent infections and likely immunosuppression.

Detection of asinine gammaherpesviruses in association with pulmonary fibrosis in free-ranging donkeys.

A mortality event among recently captured feral donkeys (Equus asinus) occurred in south-central Utah in 2016. The deaths were sporadic, and clinical signs were indicative of respiratory disease, likely associated with an infectious etiology. Ten of 13 donkeys autopsied had moderate-to-severe interstitial fibrosing pneumonia, and one had pyogranulomatous pneumonia. Consensus PCRs directed toward the DNA polymerase and DNA packaging terminase subunit 1 for herpesviruses were performed followed by sequencing of the PCR amplicons and phylogenetic analysis. Asinine herpesvirus 4 (AsHV4) and 5 (AsHV5) were consistently identified in lung tissues of affected donkeys. No other herpesviruses were identified, and herpesviral DNA was not detected in lung tissues of 2 donkeys without evidence of respiratory disease. The detection of asinine gammaherpesviruses may have been associated with the lesions described. AsHV4 and AsHV5 have been reported in previous studies as novel gammaherpesviruses based on sequences obtained from donkeys with interstitial pneumonia and marked syncytial cell formation. Our findings suggest that the association of asinine gammaherpesviruses with respiratory conditions in equids deserves further attention.

Metastatic cholangiocarcinoma mimicking tuberculosis in a cow.

Here we describe a metastatic hepatic cholangiocarcinoma (cholangiocellular carcinoma) in a 14-y-old Beefmaster cow that was euthanized because of depression and progressive weight loss. Gross changes included coalescing, white-to-yellow, firm-to-hard nodules with central areas of necrosis and mineralization that effaced much of the hepatic parenchyma, omentum, mesentery, ruminal serosa, and diaphragm. A fresh sample of a hepatic nodule was submitted for a modified acid-fast (MAF) stain during autopsy to rule out tuberculosis. The MAF stain was inconclusive, and the sample was subsequently submitted for a PCR assay for Mycobacterium spp. Histologically, all nodules consisted of a neoplastic proliferation of epithelial cells surrounded by extensive areas of desmoplasia, consistent with a metastatic cholangiocarcinoma. PCR for Mycobacterium spp. was negative. Although the histologic diagnosis in our case was metastatic hepatic cholangiocarcinoma, gross changes were strikingly similar to those described in cases of tuberculosis, highlighting the need to remain vigilant in the identification of zoonotic and suspected foreign animal diseases during autopsy to protect human health.

A Novel Adenovirus Detected in Bering-Chukchi-Beaufort Seas Bowhead Whale (Balaena mysticetus): Epidemiologic Data and Phylogenetic Characterization.

Adenoviruses are common pathogens infecting a wide range of vertebrates. Few cetacean adenoviruses have been described in the literature, and their pathogenicity is still unclear. Using PCR-based viral and bacterial pathogen surveillance in Bering-Chukchi-Beaufort seas bowhead whales (Balaena mysticetus) legally harvested 2012-15 during Alaskan aboriginal subsistence hunts, six of 59 bowhead whales (10%) tested positive for adenovirus DNA in the spleen. We found a high degree of sequence divergence from other mastadenoviruses, suggesting these may represent a novel species, tentatively named bowhead whale adenovirus. The sequences detected are distinct from adenoviruses previously identified in bottlenose dolphins (Tursiops truncatus) and harbor porpoises (Phocoena phocoena), forming two distinct clades in the cetacean hosts. The clinical impact is unclear, since no histopathologic evidence of adenovirus-associated disease was found. Furthermore, detection of adenovirus DNA in the spleen, contrary to other cetacean adenoviruses detected in the intestinal tract, may suggest a broader tissue tropism. Our study demonstrates adenovirus infection in bowhead whales and the usefulness of molecular diagnostics to discover and genetically characterize novel viruses in marine mammals.

Canine infectious respiratory disease: New insights into the etiology and epidemiology of associated pathogens.

Canine infectious respiratory disease (CIRD) is a syndrome where multiple viral and bacterial pathogens are involved sequentially or synergistically to cause illness. There is limited information regarding the prevalence of pathogens related to CIRD in the United States as well as the role of co-infections in the pathogenesis of the syndrome. We aimed to conduct a comprehensive etiologic and epidemiologic study of multiple CIRD agents in a diverse dog population using molecular methods and statistical modeling analyses. In addition, a novel probe-based multiplex real-time PCR was developed to simultaneously detect and differentiate two species of Mycoplasma (M. canis and M. cynos). Canine adenovirus, canine distemper virus, canine parainfluenza virus, coronavirus, influenza A virus (H3N2 and H3N8), Bordetella bronchiseptica, M. canis, M. cynos and Streptococcus equi subsp. zooepidemicus were investigated in specimens from clinically ill and asymptomatic dogs received at the Athens Veterinary Diagnostic Laboratory. Results showed low occurrence of classical CIRD agents such as B. bronchiseptica, canine adenovirus and distemper virus, while highlighting the potential role of emerging bacteria such as M. canis and M. cynos. Statistical modeling analyses of CIRD pathogens emphasized the impact of co-infections on the severity of clinical presentation, and showed that host factors, such as animal age, are the most important predictors of disease severity. This study provides new insights into the current understanding of the prevalence and role of co-infections with selected viruses and bacteria in the etiology of CIRD, while underscoring the importance of molecular diagnosis and vaccination against this disease.

Actinomadura vinacea isolated from a nonhealing cutaneous wound in a cat.

A 6-year-old, spayed female, domestic shorthair cat was presented to the University of Georgia Veterinary Teaching Hospital for a 3-year history of a nonhealing wound on the right tarsus. The wound temporarily resolved with medical management, but intermittently recurred when antimicrobials were discontinued. At presentation, the wound had become refractory to antimicrobial therapy. Physical examination revealed a 1 cm diameter crust along the medial aspect of the right tarsus. Proximal to the crust, were 2 non-painful, fluctuant swollen areas that were free of drainage. Cytologic evaluation revealed atypical granulated cells, and a mesenchymal neoplasm was interpreted as a top differential diagnosis. Histopathology revealed marked, chronic, multifocal, pyogranulomatous dermatitis with abundant intralesional colonies of gram-positive, acid-fast-negative, filamentous bacteria. PCR and sequencing confirmed the infection to be caused by Actinomadura vinacea.

Cellulitis caused by the Burkholderia cepacia complex associated with contaminated chlorhexidine 2% scrub in five domestic cats.

Isolates of the Burkholderia cepacia complex (BCC) are known as plant and human pathogens. We describe herein BCC infections as the cause of subcutaneous abscesses and purulent cellulitis in 5 cats. All cats were presented with an open wound, and 4 received standard wound care and empiric antibiotic therapy. Despite treatment, clinical signs worsened in 4 cats. Isolates of the BCC were obtained from all 5 cases. Two cats were submitted for postmortem examination. Subcutaneous abscesses with draining fistulas were observed. Histopathology revealed severe, pyogranulomatous cellulitis with intralesional gram-negative bacilli. Based on susceptibility results, the other 3 cats were administered effective antibiotics and recovered without complications. The BCC was cultured from the 2% chlorhexidine surgical scrub solution used in the clinic, suggesting the source of infection for 4 of 5 cats. Given the ability to grow in antiseptic solutions, the extra steps required to culture from antiseptics, and innate multidrug resistance, the BCC poses a challenge to both detect and treat. Although the BCC causes disease almost exclusively in humans with cystic fibrosis or immunodeficiency, the bacteria should also be a differential for nosocomial infections in veterinary patients.

Post-operative Salmonella surgical site infection in a dog.

Following decompressive surgery for degenerative lumbosacral stenosis, a 6-year-old German shepherd dog developed a subcutaneous infection at the surgical site and discospondylitis at the lumbosacral intervertebral disc. Salmonella enterica subsp. enterica, serotype Dublin was recovered from the surgical site. Salmonella of a different serovar was isolated from a sample of the raw meat-based diet that the owner fed the dog.

Infection postopératoire du site chirurgical parSalmonellachez un chien. Après une chirurgie de décompression pour une sténose lombo-sacrée dégénérative, un chien Berger allemand âgé de 6 ans a développé une infection sous-cutanée au site chirurgical et une discospondylite au disque intervertébral lombo-sacré. Salmonella enterica sous-esp. enterica de sérotype Dublin a été isolée du site chirurgical. Une salmonelle d'un sérovar différent a été isolée d'un échantillon de l'alimentation à base de viande crue donnée par le propriétaire au chien.(Traduit par Isabelle Vallières).

Systemic Trichosporon loubieri infection in a cat.

Our study describes a case of systemic Trichosporon loubieri infection in a cat with acute dyspnea, anorexia, and aggressiveness. Physical examination revealed multiple ulcerative cutaneous lesions on the abdomen, neck, and thorax. Thoracic radiographs and ultrasound showed multiple mediastinal nodules and marked pleural effusion, respectively. A cutaneous biopsy from the ulcerated wounds revealed necrogranulomatous dermatitis and panniculitis with numerous intralesional fungal hyphae. Fungal culture on fresh swab samples from the cutaneous lesions yielded growth of a fungal organism that was further identified as Trichosporon loubieri by PCR and DNA sequencing. The cat was subsequently euthanized and submitted to autopsy. Gross pathology changes consisted of multifocal to coalescing white nodules ranging from 5 to 10 mm in diameter that expanded the mediastinal fat, intrathoracic lymph nodes, lungs, and costal pleura. These lesions consisted of areas of necrogranulomatous inflammation with numerous intralesional fungal hyphae morphologically similar to those observed in the cutaneous biopsy sample. Gross and histologic changes were consistent with a systemic fungal infection, and the etiologic diagnosis was supported by fungal culture. Fungal identity was confirmed by DNA sequencing of D1-D2 and TS1 regions.

Antemortem Diagnosis and Successful Treatment of Pulmonary Candidiasis in a Sun Conure (Aratinga solstitialis).

An adult male sun conure (Aratinga solstitialis) was evaluated because of lethargy, ruffled feathers, and decreased appetite. Physical examination revealed hypothermia, dehydration, dyspnea, and crop distention. Results of a complete blood cell count revealed a marked inflammatory leukogram, and cytologic examination of a crop swab sample identified gram-negative bacilli and occasional yeast organisms. Radiographs demonstrated an opaque, ill-defined, soft tissue structure in the caudal coelom just cranial to the renogonadal silhouette, loss of serosal detail, and splenomegaly. Endoscopic examination revealed a pale, granuloma-like structure within the caudal aspect of the left lung, splenomegaly, and an enlarged proventriculus. Intraoperative cytologic examination of a biopsy sample of the lesion demonstrated yeast organisms, and a subsequent culture of the biopsy sample revealed Candida albicans . The bird was treated intraoperatively with intralesional amphotericin B. Postoperative treatment consisted of meloxicam, trimethoprim sulfa, amphotericin B by nebulization, and systemic itraconazole and fluconazole. The bird made a complete recovery, was discontinued from all medications, and has remained asymptomatic for 6 months. Although rare, pulmonary candidiasis should be on the list of differential diagnoses for any respiratory infection in birds. Endoscopic biopsy, cytology, and fungal culture were valuable in making the diagnosis.

Rotura uterina en la semana 19 de gestación por placenta percreta / Uterine rupture at week 19 of gestation placenta percreta

La rotura uterina durante el embarazo es una complicación obstétrica con graves consecuencias para la madre y el feto. La rotura uterina por placenta percreta es inusual. Comunicamos el caso de una paciente de 30 años, con embarazo de 19 semanas, quien ingresó por dolor abdominal de 24 horas de evolución, a predominio en la región hipogástrica, que durante su evolución padeció afectación hemodinámica y aumento del dolor abdominal. Por ultrasonido se observó líquido libre en la cavidad abdominal y mediante la laparotomía se encontró rotura uterina, se extrajo la placenta y el feto dentro de la bolsa amniótica y se realizó histerectomía. El diagnostico se confirmó mediante estudio histopatológico. (AU)

Uterine rupture during pregnancy is an obstetric complication with serious consequences for the mother and fetus. Uterine rupture is unusual placenta percreta. We report the case of a patient of 30 years, with 19 weeks pregnant, was admitted with abdominal pain 24 hours after onset, predominantly in the hypogastric region, during its evolution suffered hemodynamic compromise and increased abdominal pain. By ultrasound revealed free fluid in the abdominal cavity by laparotomy and uterine rupture was found, the placenta and the fetus within the amniotic sac was removed and hysterectomy was performed. The diagnosis was confirmed by histopathology. (AU)

Alternaria fungal dermatitis in a free-ranging javelina (Pecari tajacu).

We report a javelina from Pinal County, Arizona, USA, with severe fungal dermatitis and cellulitis. Extreme emaciation and rostral disfiguration, including left-lateral displacement of the nasal planum, justified euthanasia. A pus-filled tract within the rostrum was observed. Histopathology revealed granulomatous inflammation with hyphae morphologically consistent with Alternaria sp. isolated by culture.

Panniculitis attributable to Mycobacterium goodii in an immunocompetent dog in Georgia.

CASE DESCRIPTION: A 5-year-old 38.3-kg (84.5-lb) mixed-breed dog was examined because of acute onset of lethargy and anorexia. Four days later, a raised, firm, warm 15 × 10-cm lesion was detected in the right caudal paralumbar area. CLINICAL FINDINGS: Cephalexin treatment yielded a poor response. Formalin-fixed tissue and fluid samples from the cystic areas of the lesion were submitted for cytologic and histologic examinations, routine bacterial and mycobacterial culture, and genus identification and 16S partial sequencing via PCR assays. Cytologic examination revealed chronic pyogranulomatous inflammation. Histologic examination by use of routine, Giemsa, silver, acid-fast, and modified acid-fast stains revealed multifocal nodular granulomatous panniculitis without identifiable organisms. Mycobacteria were initially identified via PCR assay and mycobacterial culture within 3 days. Mycobaterium goodii was speciated by use of partial 16S RNA sequence analysis. TREATMENT AND OUTCOME: The lesion resolved after long-term treatment with a combination of rifampin and clarithromycin and insertion of a Penrose drain. There has been no recurrence of the condition. CLINICAL RELEVANCE: M goodii is an environmental rapidly growing mycobacterium and is a zoonotic pathogen. Infections have not been previously reported in domestic animals in North America, although there are rare reports of infection in humans associated with surgery, especially surgical implants. Domestic animals are a potential sentinel for this non-tuberculous mycobacterial infection in humans, although lack of speciation in infections of domestic animals likely underestimates the potential public health importance of this pathogenic organism. Current microbiological molecular methods allow for a rapid and inexpensive diagnosis.

Investigation of shell disease in map turtles (Graptemys spp.).

Nineteen map turtles (Graptemys spp.) maintained under natural conditions were investigated because of chronic shell abnormalities. Animals were evaluated using a novel shell scoring system that divided the 54 scutes into six regions, with each region scored for lesion extent and severity, and summated to produce a total shell disease score (TSDS). Complete blood counts and various biochemistry analytes (total protein, albumin, globulin, urea, uric acid, 25-hydroxycholecalciferol, phosphorus, and ionized and total calcium) were measured. Under ketamine-medetomidine-morphine anesthesia, cytology tape strips and full thickness shell biopsies were collected aseptically for microbiologic, histologic (including scoring of biopsy quality), and ultrastructural evaluations. The TSDSs were low and ranged from 4 to 22 (median = 9) out of a possible score of 54. There were no correlations between TSDS and any hematologic or biochemistry parameter. The histologic quality of shell biopsies was good, and normal shell structure, by both light and electron microscopy, is described. Small clefts and pitting lesions were noted in 8/19 sections. There was no evidence of erosion, ulceration, inflammation, or infectious agents, but algae and diatoms were observed. Six biopsies yielded aerobic isolates (Chryseobacterium indologenes, Aeromonas hydrophila, Ralstonia pickettii, and Morganella morganii), whereas 11 shell samples grew various clostridial anerobes. No fungal organisms were cultured. Although the etiology of the lesions described remains unknown, the use of a scoring system in conjunction with full thickness biopsies is suggested to help standardize investigations into chelonian shell disease in the future.

Johne's disease in a free-ranging white-tailed deer from Virginia and subsequent surveillance for Mycobacterium avium subspecies paratuberculosis.

Johne's disease (paratuberculosis) was diagnosed in a 2-yr-old, male, free-ranging white-tailed deer (Odocoileus virginianus) from Fauquier County, Virginia, USA, based on histopathology and culture for Mycobacterium avium subspecies paratuberculosis. Clinical and pathologic findings included emaciation; loss of body fat; chronic diarrhea; severe, chronic, diffuse granulomatous colitis with intrahistiocytic acid-fast bacilli; moderate, chronic granulomatous lymphadenitis with intrahistiocytic acid-fast bacilli; as well as moderate chronic, multifocal, lymphoplasmacytic hepatitis. These findings are consistent with previous reports of Johne's disease in cervids. Subsequent targeted surveillance of 10 emaciated deer with diarrhea, as well as sampling of 72 asymptomatic deer for M. avium subsp. paratuberculosis using culture of multiple tissue types, as well as serology using an enzyme-linked immunosorbent assay (ELISA) optimized for cervid antibody detection, did not reveal any additional cases of infection in this geographic region. To date, this appears to be an isolated case of Johne's disease in a free-ranging white-tailed deer, and infection with the causative agent for Johne's disease appears to be an infrequent occurrence in deer from this region. The origin of infection was most likely domestic ruminants. This is the first report of clinical Johne's disease in a free-ranging white-tailed deer outside of the Florida Keys, USA. Stressors, such as high deer population density and low selenium levels, may have contributed to the development of clinical disease in this case and warrant further investigation.

Prevalence and characterization of urinary tract infections in dogs with surgically treated type 1 thoracolumbar intervertebral disc extrusion.

OBJECTIVE: To determine the prevalence of urinary tract infections (UTI), factors that correlate positively with UTI, and whether identified UTI are most likely community- or hospital acquired in dogs with surgically treated type 1 thoracolumbar intervertebral disc (IVD) extrusions. STUDY DESIGN: Prospective cross-sectional clinical study. SAMPLE POPULATION: Dogs (n=92) that were surgically treated for a thoracolumbar extradural compressive spinal cord lesion that was consistent with type 1 IVD extrusion. METHODS: Dogs were evaluated for bacterial lower UTI when possible by cystocentesis and urine culture before surgery, and 48-72, 96-120 hours, and 7 days after surgery while hospitalized. Paraparesis, confirmation of thoracolumbar extruded nucleus pulposus, and informed owner consent were required for study inclusion. Urine specimens (n=297) were cultured and both objective and subjective clinical data were obtained. RESULTS: Prevalence of UTI in dogs with surgically treated type 1 thoracolumbar IVD extrusion was 27% (25 dogs). Temporal prevalence of UTI was 15% (13/89) before surgery, 12% (11/91) at 2-3 days, 16% (12/76) at 4-5 days, and 20% (8/41) at 7 days after surgery. Statistically significant factors affecting UTI prevalence included neurologic and urinary status, sex, administration of perioperative antibiotics, and amount of time body temperature was <35 degrees C during anesthesia. CONCLUSION: UTI are common in dogs with surgically treated type 1 thoracolumbar IVD extrusion. Females, dogs that cannot ambulate or voluntarily urinate, dogs not administered perioperative cefazolin, and dogs whose body temperature falls <35 degrees C during anesthesia have a higher incidence of UTI. CLINICAL RELEVANCE: All dogs with surgically treated type 1 thoracolumbar IVD extrusion should be monitored for the presence of UTI; however, close attention should be paid to females and dogs that cannot ambulate or voluntarily urinate.

Characterization of multidrug-resistant Escherichia coli isolates associated with nosocomial infections in dogs.

Multidrug-resistant opportunistic pathogens have become endemic to the veterinary hospital environment. Escherichia coli isolates resistant to 12 antibiotics were isolated from two dogs that were housed in the intensive care unit at The University of Georgia Veterinary Teaching Hospital within 48 h of each other. Review of 21 retrospective and prospective hospital-acquired E. coli infections revealed that the isolates had similar antibiotic resistance profiles, characterized by resistance to most cephalosporins, beta-lactams, and the beta-lactamase inhibitor clavulanic acid as well as resistance to tetracycline, spectinomycin, sulfonamides, chloramphenicol, and gentamicin. E. coli isolates with similar resistance profiles were also isolated from the environment in the intensive care unit and surgery wards. Multiple E. coli genetic types were endemic to the hospital environment, with the pulsed-field gel electrophoresis fingerprint identified among E. coli isolates from diseased animals and the hospital environment matching. The extended-spectrum cephalosporin resistance in these nosocomial E. coli isolates was attributed to the cephamycinase-encoding gene, bla(CMY2). Chloramphenicol resistance was due in part to the dissemination of the florfenicol resistance gene, flo, among these isolates. Resistance encoded by both genes was self-transmissible. Although bla(CMY2) and flo were common to the polyclonal, nosocomial E. coli isolates, there was considerable diversity in the genetic compositions of class 1 integrons, especially among isolates belonging to the same genetic type. Two or more integrons were generally present in these isolates. The gene cassettes present within each integron ranged in size from 0.6 to 2.4 kb, although a 1.7-kb gene cassette was the most prevalent. The 1.7-kb gene cassette contained spectinomycin resistance gene aadA5 and trimethoprim resistance gene dfrA17.