Septicemia in a neonatal calf associated with Chromobacterium violaceum.

Chromobacterium violaceum infections are highly fatal and rarely reported in domestic animals. This report describes a fatal case of C. violaceum septicemia in a 7-day-old female beef calf. The calf had necrosuppurative omphalophlebitis, necrotizing interstitial pneumonia, necrosuppurative hepatitis and splenitis, anterior uveitis with hypopyon, suppurative polyarthritis, and disseminated hemorrhagic meningitis with multifocal necrotizing encephalitis. Histologically, clusters of gram-negative bacilli were found in many of the lesions. C. violaceum was isolated in high numbers from the lungs, liver, spleen, carpus, and in pure culture from the cerebrospinal fluid. To our knowledge, this is the first case report of chromobacteriosis in a calf.

Pulmonary Phialemonium curvatum phaeohyphomycosis in a Standard Poodle dog.

Phialemonium curvatum, frequently misidentified as an Acremonium species, is reported here as a new agent of pulmonary phaeohyphomycosis in a Standard Poodle dog, and added as a new species in the genus to cause mycoses in canines. In vitro susceptibility data, for both human and animal isolates, suggests resistance to amphotericin B and susceptibility to the triazole agents itraconazole, voriconazole, and posaconazole.

Effects of seasonal climatic conditions on the diagnosis of Mycobacterium avium subspecies paratuberculosis in dairy cattle.

Validity of Johne's disease programs and control protocols that rely on established cut points [e.g., specified sample-to-positive (S/P) ratios] for ELISA serological tests depends on interpreted results that are not susceptible to variable test accuracy. It was hypothesized that seasonal variability exists in serological response to Mycobacterium avium subsp. paratuberculosis (MAP) infection. Further, a reciprocal response may occur, resulting in greater risk of fecal shedding in subclinically infected animals. A testing regimen was invoked that included multiple testing of individual adult cows during the 4 seasons. Serum was collected on a cyclic, monthly basis from 3 randomly selected cohorts of dairy cows, and fecal samples were collected from the 20% of cows with the greatest ELISA test S/P ratios. Staggered, quarterly sampling was continued for 1 yr, and at the conclusion, serum was analyzed en masse. The ELISA outcome values (i.e., S/P ratio) were treated both as categorical and continuous variables. The potential lagged effects of temperature-related seasonality on S/P ratio, as well as the potential for a change in test result caused by temperature were assessed. Results for fecal culture were analyzed on a categorical scale and compared with the ELISA results to explore the possibility of reciprocal fecal shedding. No significant seasonal effects on either S/P ratios or the proportion of cows seropositive to MAP were observed. Furthermore, no evidence was found linking temperature-related seasonality to a reciprocal increase in the risk of fecal culture positivity for MAP.

Systemic Pasteurella haemolytica infection as a rare sequel to avirulent live Pasteurella haemolytica vaccination in cattle.

Eleven cases of systemic Pasteurella haemolytica infection in cattle were identified from routine diagnostic laboratory submissions during the falls of 1988, 1989, and 1991. All cases came with a history of recent vaccination with an avirulent live culture P. haemolytica product. Nine of 11 cases involved cattle vaccinated between 2 and 18 days previously with this product. Ten of 11 cases involved 182-227-kg beef calves that were vaccinated between September and November during routine processing for entry into feedlots. The morbidity and mortality was generally low. The major pathologic findings included meningitis, injection site abscessation and/or cellulitis, and polyarthritis. Systemic infection was indicated in all cases by the isolation of P. haemolytica from 2 or more organs or distinct anatomical sites. In 6 cases, the vaccine injection site was cultured, and in all 6 cases, P. haemolytica was isolated. Three separate P. haemolytica isolates from 2 cases were further studied by restriction enzyme analysis (REA). These isolates were from tissues with suppurative inflammation, including the brain, joint, and injection site. The REA patterns of each of these 3 isolates were identical to the REA pattern of the vaccine masterseed, which strongly suggested that the organisms causing systemic infection were the same as the organism used to produce the vaccine. Because the overall incidence was quite low, other factors, such as stress, probably played a major role in the expression of this syndrome.

Effect of feeding lasalocid to pregnant ewes experimentally infected with Toxoplasma gondii.

Sixteen 50 day gestational ewes were fed lasalocid at the rate of 30 g t-1 and were orally inoculated with 100 infective Toxoplasma gondii oocysts 5 days after beginning feeding of lasalocid. Seventeen control ewes were similarly inoculated with T. gondii and were not fed lasalocid. The rate of abortion and neonatal mortality in both treated and untreated ewes was similar, indicating that feeding lasalocid was not effective in preventing T. gondii abortion in sheep.

Attaching and effacing Escherichia coli infection as a cause of diarrhea in young calves.

A form of enteric Escherichia coli infection was identified in 60 calves from 59 farming operations. The E coli responsible for these infections principally colonized the colon, inducing a distinctive lesion described as attaching and effacing. Hemorrhagic enterocolitis or blood in the feces was observed on 40% of the farms. Of affected calves, 86.6% were dairy calves (average age, 11.8 days). Forty-four calves were infected concurrently with other enteropathogens (cryptosporidia, rotavirus, coronavirus, enterotoxigenic E coli, bovine viral diarrhea virus, coccidia). Verotoxin-producing E coli was recovered from 31 calves; 8 were serotype O111:NM isolates, 3 were serotype O5:NM, and 1 was serotype O26:NM.

Attaching and effacing Escherichia coli infections in calves, pigs, lambs, and dogs.

Attaching and effacing Escherichia coli (AEEC) adhere to mucosal epithelium in both small and large intestine and induce a distinctive lesion characterized by an irregular scalloped appearance of the epithelial layer. Infection with attaching and effacing E. coli was detected in 14 calves, 7 pigs, 2 lambs, and 3 dogs. Affected animals were from farms and kennels in South Dakota, Minnesota, Iowa, Nebraska, and Wisconsin. Ages of affected animals were calves, 2 days to 4 months; pigs, 1-6 weeks; lambs, 1 week; and dogs, 7-8 weeks. Clinical signs included diarrhea in all animals, but other nonenteric disease problems were present in some animals. Concurrent infection with other enteropathogens was detected in 9 calves and 5 pigs. Infection with AEEC appeared to be the sole cause of illness and death in some animals. There was evidence of intestinal hemorrhage in 5 of the calves and in all 3 dogs. Attaching and effacing lesions varied from small scattered foci to widespread involvement of large areas of intestinal mucosa. Verotoxin was produced by E. coli strains isolated from 9 calves, but not by strains from pigs, lambs, or dogs.

Necropsy of sheep and goats.

In this article, diseases will be discussed by system. Common differential diagnoses that may be associated with gross lesions are pointed out, and practical laboratory tests are presented that may help establish a specific diagnosis.

Comparison of minimal inhibitory concentration and disk-diffusion antimicrobic sensitivity testing of bacterial pathogens isolated from food animals.

Disk-diffusion sensitivity tests were conducted with the antimicrobics sulfathiazole, gentamicin, erythromycin, kanamycin, penicillin, ampicillin, and spectinomycin on 300 to 350 bacterial isolates of food animal origin. The minimal inhibitory concentration of each antimicrobic was also determined for each bacterial isolate, using a microdilution technique. Results indicated that inhibitory zone sizes should be larger for some antimicrobics when testing animal pathogens than those zone sizes recommended for testing human pathogens. In addition, zone interpretive data are reported for spectinomycin, a drug for which such data were previously lacking.

Brucella ovis-induced abortion in ewes.

Aborted fetuses and placental tissue from ewes in 2 flocks were submitted for diagnostic examinations. Brucella ovis was isolated from fetal lung or abomasal contents, or both. Placentitis was a consistent gross lesion. Microscopic lesions included suppurative pneumonia and placentitis.

Antimicrobial resistance in Escherichia coli strains isolated from pigs with diarrhea.

Antimicrobial sensitivities were determined for 1,037 Escherichia coli isolates cultured from the intestines of pigs with diarrhea. In vitro resistance by at least 1 isolate of E coli was demonstrated to each antimicrobial tested. Isolates from suckling pigs were more often resistant to chloramphenicol than were those from weaned pigs. Significantly more E coli from weaned pigs were resistant to kanamycin and neomycin than were those from suckling pigs. Escherichia coli that were the primary cause of diarrhea (colibacillosis isolates) were significantly more resistant to kanamycin, neomycin, and spectinomycin than were noncolibacillosis isolates. The opposite was true for ampicillin.

Antimicrobial sensitivity patterns of Haemophilus pleuropneumoniae isolates from pigs with pneumonia.

Antimicrobial sensitivity patterns were determined for 53 isolates of Haemophilus pleuropneumoniae from pneumonic porcine lung tissue. All strains were sensitive to chloramphenicol, gentamicin, spectinomycin, and sulfachlorpyridazine. Other antimicrobials tested had less efficacy for in vitro inhibition of H pleuropneumoniae.

Plasmid-mediated antimicrobial resistance in Haemophilus pleuropneumoniae.

Haemophilus pleuropneumoniae, isolated from the lungs of pig, was resistant to ampicillin, streptomycin, and sulfadiazine. This isolate, SD-1, possessed 1 plasmid (pVM105) coded for resistance to ampicillin and sulfadiazine, and the other (pVM104) for resistance to streptomycin and sulfadiazine. A 2nd isolate of H pleuropneumoniae, SD-2, recovered from a pig in a different outbreak of porcine pleuropneumonia, was resistant to streptomycin and sulfadiazine. These resistance determinants were on 1 plasmid (pVM106). All 3 patients were nontransmissible and small (pVM105 = 3.6 x 10(6) daltons, pVM104 and pVM106 = 2.3 x 10(6) daltons. The basis for resistance to ampicillin, encoded on plasmid pVM105, was due to a beta-lactamase. This beta-lactamase was highly active on penicillin G and ampicillin, moderately active on cephalothin, and inactive on oxacillin, indicating a TEM type of beta-lactamase.