Objective—To determine the organisms most commonly
isolated from pleural fluid from dogs and cats
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:
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
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
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
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
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.
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.
Objective—To determine molecular characteristics of
Clostridium difficile isolates from foals with diarrhea
and identify clinical abnormalities in affected foals.
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
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
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
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)