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- Author or Editor: Dwight C. Hirsh x
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Abstract
Objective—To determine the organisms most commonly isolated from pleural fluid from dogs and cats with pyothorax.
Design—Retrospective study.
Animals—51 dogs and 47 cats.
Procedure—Results of bacteriologic culture of pleural fluid samples obtained by means of thoracentesis were obtained from medical records. To obtain information on in vitro antimicrobial susceptibility of organisms commonly isolated from dogs and cats, records of all dogs and cats examined during 1998 were reviewed, and information was obtained on identity and in vitro antimicrobial susceptibility of aerobic organisms isolated from samples other than urine or urinary tract samples.
Results—Median ages of dogs and cats were 4 years. Bacteria were isolated from pleural fluid samples from 47 of 51 (92%) dogs and 45 of 47 (96%) cats. Obligate anaerobic bacteria were isolated from 28 dogs and 40 cats. A mixture of obligate anaerobic and facultative bacteria was isolated from 17 dogs and 20 cats. Samples from cats most often yielded a member of the nonenteric group (most commonly members of the genus Pasteurella), whereas those from dogs more often yielded a member of the family Enterobacteriaceae (most commonly E coli).
Conclusion and Clinical Relevance—Results suggest that antimicrobial agents chosen for the initial treatment of dogs and cats with pyothorax should be active against a mixture of obligate anaerobic and facultative bacteria. (J Am Vet Med Assoc 2000;216: 359–363)
Abstract
Objective—To assess the strain heterogeneity of enrofloxacin-resistant Escherichia coli associated with urinary tract infections in dogs at a veterinary medical teaching hospital (VMTH). In addition, strains from other veterinary hospitals in California were compared with the VMTH strains to assess the geographic distribution of specific enrofloxacin-resistant E coli isolates.
Design—Bacteriologic study.
Sample Population—56 isolates of E coli from urine samples (43 isolates from dogs at the VMTH, 13 isolates from dogs from other veterinary clinics in California).
Procedures—Pulsed field gel electrophoresis was performed on 56 isolates of E coli from urine samples from 56 dogs. All 56 isolates were tested for susceptibility to amoxicillin, chloramphenicol, enrofloxacin, tetracycline, trimethoprim-sulphamethoxazole, cephalexin, and ampicillin. Enrofloxacin usage data from 1994 to 1998 were obtained from the VMTH pharmacy.
Results—Several strains of enrofloxacin-resistant E coli were collected from urine samples from the VMTH, and strains identical to those from the VMTH were collected from other veterinary clinics in California. For the isolates that did share similar DNA banding patterns, variable antibiotic resistance profiles were observed.
Conclusions and Clinical Relevance—The increased occurrence of enrofloxacin-resistant E coli from urine samples from dogs at the VMTH was not likely attributable to a single enrofloxacinresistant clone but may be attributed to a collective increase in enrofloxacin resistance among uropathogenic E coli in dogs in general. (J Am Vet Med Assoc 2002;220:190–192)
Abstract
Objective—To determine molecular characteristics, antimicrobial susceptibility, and toxigenicity of Clostridium difficile isolates from horses in an intensive care unit and evaluate associations among severity of clinical disease with specific strains of C difficile.
Design—Prospective study.
Animals—130 horses.
Procedures—Feces were collected from horses admitted for acute gastrointestinal tract disease with loose feces and submitted for microbial culture and immunoassay for toxin production. Polymerase chain reaction assays were performed on isolates for toxins A and B genes and strain identification.
Results—Isolates were grouped into 3 strains (A, B, and C) on the basis of molecular banding patterns. Toxins A and B gene sequences were detected in 93%, 95%, and 73% of isolates of strains A, B, and C, respectively. Results of fecal immunoassays for toxin A were positive in 40%, 63%, and 16% of horses with strains A, B, and C, respectively. Isolates in strain B were resistant to metronidazole. Horses infected with strain B were 10 times as likely to have been treated with metronidazole prior to the onset of diarrhea as horses infected with other strains. Duration from onset of diarrhea to discharge (among survivors) was longer, systemic inflammatory response syndromes were more pronounced, and mortality rate was higher in horses infected with strain B than those infected with strains A and C combined.
Conclusions and Clinical Relevance—Horses may be infected with a number of heterogeneous isolates of C difficile. Results indicated that toxigenicity and antimicrobial susceptibility of isolates vary and that metronidazole-resistant strains may be associated with severe disease.
Abstract
Objective—To determine molecular characteristics of Clostridium difficile isolates from foals with diarrhea and identify clinical abnormalities in affected foals.
Design—Retrospective study.
Animals—28 foals with C difficile-associated diarrhea.
Procedure—Toxigenicity, molecular fingerprinting, and antibiotic susceptibility patterns were determined. Information on signalment, clinical findings, results of clinicopathologic testing, whether antimicrobials had been administered prior to development of diarrhea, and outcome was obtained from the medical records.
Results—Twenty-three (82%) foals survived. Toxin A and B gene sequences were detected in isolates from 24 of 27 foals, whereas the toxin B gene alone was detected in the isolate from 1 foal. Results of an ELISA for toxin A were positive for fecal samples from only 8 of 20 (40%) foals. Ten of 23 (43%) isolates were resistant to metronidazole. Molecular fingerprinting revealed marked heterogeneity among isolates, except for the metronidazole-resistant isolates. Sixteen foals had tachypnea. Hematologic abnormalities were indicative of inflammation. Common serum biochemical abnormalities included metabolic acidosis, hyponatremia, hypocalcemia, azotemia, hypoproteinemia, hyperglycemia, and high enzyme activities. Passive transfer of maternal antibodies was adequate in all 12 foals evaluated.
Conclusions and Clinical Relevance—Results suggest that a large percentage of C difficile isolates from foals with diarrhea will have the toxin A and B gene sequences. Because of the possibility that isolates will be resistant to metronidazole, susceptibility testing is warranted. Clostridium difficile isolates from foals may have a substantial amount of molecular heterogeneity. Clinical and hematologic findings in affected foals are similar to those for foals with diarrhea caused by other pathogens. (J Am Vet Med Assoc 2002;220:67–73)
Abstract
Objective—To characterize clinical, serologic, bacteriologic, cytologic, and pathologic endometrial responses of mares to 2 donkey-origin atypical bacterial isolates resembling Taylorella equigenitalis.
Design—Prospective in vivo study.
Animals—10 healthy mares.
Procedure—Mares in estrus (2/group) were inoculated by intrauterine infusion with 2 isolates of classic T equigenitalis or 2 isolates of atypical Taylorella sp or were sham-inoculated. Bacteriologic, serologic, clinical, uterine, cytologic, and pathologic endometrial responses were assessed 4, 11, 21, 35, and 63 days after inoculation and on day 111 in mares with positive culture results on day 63.
Results—One atypical isolate failed to cause infection. The second atypical isolate and both classic T equigenitalis isolates induced similar transient metritis and cervicitis. Both classic isolates and 1 atypical isolate induced anti-T equigenitalis complement-fixing antibodies detectable at day 11. Classic isolates and an atypical isolate provoked intense neutrophilic endometritis followed by a resolving, subacute, neutrophilic-mononuclear endometrial response. The atypical isolate and classic isolates were recovered from the uterus, clitoral fossa, or clitoral sinus of one or both exposed mares for as long as 111 days.
Conclusions and Clinical Relevance—Atypical Taylorella sp infections should be considered as a differential diagnosis of equine infertility in US-origin mares, even those not exposed to stallions from countries where contagious equine metritis occurs. The origins and prevalence of atypical Taylorella sp infection in US horses and donkeys are undetermined. (J Am Vet Med Assoc 2000;216:1945–1948)
