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Summary

Management practices on swine farms were analyzed to determine factor(s) associated with high prevalence of pigs that were carriers of Streptococcus suis. Samples were obtained for bacteriologic culture via direct swabbing of palatine tonsils of healthy nursery pigs on 35 farms throughout the United States. Overall, 36.7% of the pigs were determined to be carriers. Isolates of S suis were serotyped, and antimicrobial susceptibility tests were performed by use of Kirby-Bauer techniques. Streptococcus suis types 1 and 2 were most commonly isolated. All isolates were susceptible to enrofloxacin, 97% of the isolates were susceptible to ceftiofur, and 94% were susceptible to ampicillin. However, only 80% of the isolates were susceptible to penicillin, and only 18% were susceptible to tetracycline.

Environmental, managerial, nutritional, and health factors were measured on each farm. Excessive temperature fluctuation, high relative humidity, crowding, and an age spread of > 2 weeks between pigs in the same room were the 4 most commonly encountered problems on farms with higher-than-average percentages of carrier pigs. Continuous flow facilities were found on 50% of these farms, and various disease problems, vitamin E/selenium deficiency, inadequate vaccination programs (attributable to the presence of atypical serotypes), and penicillin-resistant strains were found on 6 to 28% of these farms. Overall, 83% (15/18) of farms with higher-than-average percentages of carrier pigs also had a history of clinical S suis disease.

Free access
in Journal of the American Veterinary Medical Association

Objective

To compare microbial flora and antimicrobial susceptibility patterns of isolated pathogens from the horizontal ear canal and middle ear in dogs with otitis media.

Design

Prospective study.

Animals

23 dogs with chronic bilateral otitis externa.

Procedures

Swab specimens of the horizontal ear canal and middle ear were obtained for cytologic analysis, bacterial culture, and antimicrobial susceptibility testing. Integrity of the tympanic membrane was observed. If the tympanic membrane was intact, myringotomy was performed to collect specimens.

Results

Otitis media was diagnosed in 38 of 46 (82.6%) ears evaluated. The tympanic membrane was intact in 71.1 % of the ears with otitis media. The 3 most common organisms isolated from the horizontal ear canal and middle ear were Staphylococcus intermedius, yeast, and Pseudomonas spp. A difference in total isolates or susceptibility patterns between the horizontal ear canal and middle ear was found in 34 (89.5%) ears. Compared with results of bacterial culture, cytologic examination of swab specimens was not as effective for detection of rods and cocci from the middle ear.

Clinical Implications

In dogs with chronic otitis externa, otitis media often exists even when there is an intact tympanic membrane. In our study, the same isolates were rarely found in the horizontal ear canal and middle ear. Therefore, to choose appropriate antimicrobial agents, in addition to cytologic examination, bacterial culture and susceptibility testing of swab specimens from the horizontal ear canal and middle ear should be performed. (J Am Vet Med Assoc 1998; 212:534-538)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine which antimicrobial agents. were most effective against Pseudomonas sp-infected ulcerative keratitis, and identify any trends in the various clinical conditions associated with these bacteria that might assist in effective treatment of the disease.

Design

Retrospective case series

Animals

66 horses with 70 Pseudomonas sp-infected corneal ulcers.

Procedure

We reviewed medical records of horses admitted to the George D. Widener Hospital for Large Animals, University of Pennsylvania between July 1977 and December 1994. Records of horses that had Pseudomonas sp isolated from a corneal ulcer scraping or deep swab were included in the study.

Results

Aggressive topical medical treatment was successful in 57 ulcers and most likely would have been effective in 5 additional ulcers. Antimicrobial susceptibility testing indicated susceptibilities of 87, 85, and 93% to tobramycin, gentamicin, and amikacin, respectively. Although concurrent fungal infections were identified in only 2 of 35 ulcers examined, almost three fourths of the ulcers were treated with antifungal medications prophylactically. Clinical outcomes of the 70 affected eyes included: excellent vision with minimal leukoma, 73%; enucleation, 19%; blind phthisical eye, 4%; peripheral vision only, 3%; and euthanasia of newborn, 1%.

Clinical Implications

Aggressive topical medication with microbial agents effective against Pseudomonas sp can result in excellent vision with minimal leukoma in most horses with corneal ulcers. (J Am Vet Med Assoc 1996;209:954-957)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether there was any association between results of in vitro antimicrobial susceptibility testing of pathogens isolated from cows with mild or moderate clinical mastitis and outcome of treatment.

Design—Observational study.

Animals—133 cows with mild or moderate mastitis in a single quarter.

Procedure—Cows were treated by means of intramammary infusion of pirlimycin (50 mg) in the affected quarter once daily for 2 days; additional intramammary treatments with the same product were administered if the milk continued to appear abnormal. Duration of treatment and days until clinical cure were recorded. Bacterial isolates were tested for antimicrobial susceptibility by means of a broth micro-dilution technique.

Results—Environmental streptococci, coliforms, and coagulase-negative Staphylococcus spp were the most commonly isolated pathogens. Duration of treatment and days until clinical cure were not significantly different for cows from which pathogens that were susceptible or resistant to pirlimycin were isolated. Bacteriologic cure rates 14 and 21 days after treatment were not significantly different for cows with mastitis caused by susceptible or resistant bacteria. Similar results were found when data only from cows with mastitis caused by gram-positive isolates were analyzed.

Conclusions and Clinical Relevance—In the present study, differences in clinical outcome for cows with mild or moderate mastitis that could be attributed to differences in results of in vitro susceptibility testing were not identified. The use of in vitro susceptibility testing to guide intramammary mastitis treatment cannot be recommended on the basis of results of this study. (J Am Vet Med Assoc 2005;227:1461–1468)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify clinical features of Corynebacterium urealyticum urinary tract infection in dogs and cats and antimicrobial susceptibility patterns of C urealyticum isolates.

Design—Retrospective study.

Animals—5 dogs and 2 cats.

Procedure—Medical records of dogs and cats for which C urealyticum was isolated from urine samples were reviewed. Isolates from clinical cases, along with previously lyophilized unsubtyped isolates of Corynebacterium spp collected between 1977 and 1995, were examined and, if subtyped as C urealyticum, tested for antimicrobial susceptibility.

Results—Signalment of infected animals was variable. Prior micturition disorders were common, and all animals had signs of lower urinary tract disease at the time C urealyticum infection was diagnosed. Median urine pH was 8.0; WBCs and bacteria were variably seen in urine sediment. In vitro antimicrobial susceptibility testing of 14 C urealyticum isolates revealed that all were susceptible or had intermediate susceptibility to chloramphenicol, tetracycline, and vancomycin and most were susceptible to enrofloxacin. Thickening of the bladder wall and accumulation of sediment were common ultrasonographic findings. Contrast radiography or cystoscopy revealed findings consistent with encrusting cystitis in 3 dogs. Infection resolved in 2 dogs following surgical debridement of bladder plaques and antimicrobial administration. In 2 other dogs and 1 cat treated with antimicrobials, infection with C urealyticum resolved, but urinary tract infection with a different bacterial species developed.

Conclusions and Clinical Relevance—Results suggest that preexisting urinary tract disorders are common in dogs and cats with C urealyticum infection. Treatment with appropriate antimicrobials in combination with surgical debridement might eliminate C urealyticum infection. (J Am Vet Med Assoc 2005;226:1676–1680)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate a method of aerobic bacteriologic culture of epidermal collarette specimens from dogs with superficial pyoderma and compare results with those for aerobic bacteriologic culture of abdominal skin specimens in healthy dogs.

Design—Prospective study.

Animals—22 dogs with epidermal collarettes and 24 healthy dogs.

Procedure–Dry sterile cotton swabs were rolled across epidermal collarettes or hairless areas of abdominal skin in healthy dogs and submitted for aerobic bacteriologic culture. Hemolytic colonies of gram-positive–staining cocci were tested for catalase production, and if results were positive, a coagulase test was performed. Colonies with coagulase activity were tested for the ability to ferment mannitol. Antimicrobial susceptibility testing was performed on all Staphylococcus spp that were isolated.

ResultsS intermedius was isolated from collarettes in 18 of 22 dogs with superficial pyoderma but not from healthy dogs. Estimated sensitivity and specificity of the culture method were 81.8% and 100%, respectively. There were no significant differences in the ability to culture S intermedius, the number of S intermedius isolates without resistance to antimicrobials, and the number of S intermedius isolates resistant to penicillin G when comparing dogs with superficial pyoderma for the first time and dogs with recurrent pyoderma, dogs that did or did not receive concurrent antimicrobials, and dogs with and without underlying allergic disease.

Conclusions and Clinical Relevance–Bacteriologic culture of epidermal collarette specimens was a simple and reliable method for identification of S intermedius in dogs with superficial pyoderma, regardless of history of pyoderma or current antimicrobial use. (J Am Vet Med Assoc 2005;226:904–908)

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in Journal of the American Veterinary Medical Association

Pharmacokinetic-pharmacodynamic values for amoxicillin in pigs I am writing on behalf of the Veterinary Antimicrobial Susceptibility Testing (VAST) subcommittee of the Clinical and Laboratory Standards Institute (CLSI) regarding the recent

Full access
in American Journal of Veterinary Research

causes. 3 Veterinarians commonly administer antimicrobials to reptiles without the benefit of results of bacterial culture and antimicrobial susceptibility testing, sometimes because of the patient's need of immediate treatment and the pet owner

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in Journal of the American Veterinary Medical Association

(UC) has been directed at developing and evaluating attenuated live Salmonella vaccines to prevent salmonellosis in livestock. A more recent collaboration with Mike assessed different antimicrobial susceptibility testing methodologies to improve the

Open access
in American Journal of Veterinary Research

when choosing an antimicrobial, results of bacteriologic culture and antimicrobial susceptibility testing were the most important factor. In our informal survey, however, 84% (218/259) of respondents strongly agreed or somewhat agreed that the cost of

Full access
in Journal of the American Veterinary Medical Association