Use of vancomycin hydrochloride for treatment of Clostridium difficile enteritis in Syrian hamsters

As part of an 18-month carcinogenicity study, 680 Syrian hamsters (Mesocricetus auratus) received daily gavage doses of fenazaquin, an experimental miticide. Mortality associated with severe enteritis was noticed beginning when the hamsters were 4 months old and ranged from one to five deaths per month until the hamsters were about 10 months old, when 41 deaths occurred in a 1-month period. Ante- and postmortem findings were consistent with those reported for antibiotic-induced enteritis in hamsters. Clostridium difficile was isolated from 12 of the 13 samples of cecal contents analyzed. Toxin assays of C. difficile isolates collected from 11 affected animals were positive for both cyto- and enterotoxins. Daily oral administration of vancomycin hydrochloride at a dose of 20 mg/kg was initiated when the hamsters were about 10 months old. Deaths due to C. difficile enteritis were significantly decreased within 2 weeks, and treatment was continued for 3 months. A trial withdrawal period for a subset of 64 hamsters (approximately 16% of the total population) was initiated to evaluate survival after discontinuation of the antibiotic treatment. Clostridium difficile enteritis recurred within 2 weeks and caused 19 deaths during the next month; therefore, these hamsters were returned to daily vancomycin treatment for the remainder of the study. With the exception of severe gaseous distention of the ceca, which caused death in 17 (< 4% of the total population) of the affected hamsters, vancomycin treatment did not cause any major adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous bronchopneumonia in laboratory dogs infected with untyped Mycoplasma spp

Three Mycoplasma spp. were isolated from five colony bred laboratory dogs (Canis familiaris) obtained from a single vendor. Four of these animals were Beagles and one was a mongrel. Three displayed clinical signs of respiratory disease including dyspnea, chronic coughing and moist rales, while the other two dogs were observed during thoracic surgery to have macroscopic lesions suggestive of pneumonia. All five dogs were submitted for diagnostic necropsy during which they were cultured for bacteria and mycoplasma. Mycoplasma spp. having three distinct colonial forms were isolated from the lungs of each of the animals. These three isolates were sent to the National Cancer Institute Diagnostic Microbiology Laboratory and to the National Institutes of Health, NIAID, Mycoplasmology Laboratory. Neither laboratory could serotype these isolates against antisera to 73 Mycoplasma spp., including the common canine mycoplasmas, and nine Acholeplasma spp. Histologically, the bronchopneumonia was characterized by bronchiectasis, purulent bronchiolitis, bronchial and bronchiolar epithelial hyperplasia, chronic non-suppurative peribronchiolitis and perivasculitis, bronchiolitis obliterans, and acute to subacute purulent pneumonia. The similarity between the pathologic findings in these animals and those observed in respiratory mycoplasmosis of other species, e.g. the rat, suggests a causal relationship between the isolated mycoplasmas and the pulmonary disease observed in these dogs.

Pasteurella pneumotropica in rabbits from a "Pasteurella-free" production colony

Pasteurella pneumotropica was isolated from the nasopharyngeal area of two of five rabbits obtained from a "Pasteurella-free" production colony. No evidence of disease was observed in these rabbits during clinical and necropsy examinations.

A report of an outbreak of Salmonella oranienburg in a hybrid mouse colony

Mice in a hybrid breeding colony developed symptoms compatible with a diagnosis of salmonellosis. Salmonella oranienburg was recovered from feces by conventional bacteriological techniques. Active salmonellosis appeared to be precipitated by the stress of pregnancy among breeder female BALB/c mice. Necropsy examination of the BALB/c breeder females revealed diarrhea, roughened hair coats, enlarged spleens, white foci in the liver, and skin abscesses. S. oranienburg was recovered from the spleen, cecum, oropharynx, uterus, and skin abscesses of affected mice. DBA/2N breeder males were asymptomatic and S. oranienburg was recovered from the cecum only. Breeding productivity indices dropped to unacceptable levels in rooms containing infected animals. Relatively normal production was observed among uninfected animals of the same strains in adjacent rooms, thus demonstrating the detrimental effect S. oranienburg had on this breeder colony.

Recovery and pathogenicity of several Salmonella species isolated from mice

Salmonella agona, S anatum, and S oranienburg were isolated from the feces of mice in the course of screening over 4,000 fecal samples from rodents in 22 research and production facilities. The rodents were monitored repeatedly over an 8-month period in 1979-80. These three Salmonella isolates were cultured from mice at 11 of the 22 facilities. Salmonella oranienburg was found in 56% (14 of 25) of Salmonella positive accessions, S anatum in 36% (nine of 25), S agona in 4% (one of 25), and both S oranienburg and S anatum were isolated in one accession. In order to determine the potential pathogenicity of these three Salmonella species, groups of DBA/2N mice were experimentally infected with the three agents. Several animals died acutely of apparent septicemia several days post-inoculation. Mice continued to shed the organisms in the feces for up to 5 weeks post-inoculation at which time they were necropsied and cultured extensively. Culture of visceral organs revealed mice to have systemic dissemination regardless of the Salmonella species. It was concluded that these three Salmonella species were regularly shed in the feces and, although not highly pathogenic, they had the potential to be invasive and cause disease when mice were stressed.