Antimicrobial Susceptibility of Bacteria Isolated from Freshwater Mussels in the Wildcat Creek Watershed, Indiana, United States.

Antimicrobial resistance (AMR) is a global health crisis that threatens the health of humans and animals. The spread of resistance among species may occur through our shared environment. Prevention of AMR requires integrated monitoring systems, and these systems must account for the presence of AMR in the environment in order to be effective. The purpose of this study was to establish and pilot a set of procedures for utilizing freshwater mussels as a means of surveillance for microbes with AMR in Indiana waterways. One hundred and eighty freshwater mussels were sampled from three sites along the Wildcat Creek watershed in north-central Indiana. Specimens were evaluated for the presence of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species), Escherichia coli, Campylobacter, and Salmonella species, and the isolates were tested for antimicrobial resistance. A total of 24 bacterial isolates were obtained from tissue homogenates of freshwater mussels collected at a site directly downstream from Kokomo, Indiana. Of these, 17 were Enterobacter spp., five were Escherichia coli, one was Pseudomonas aeruginosa, and one was Klebsiella pneumoniae. All isolates were resistant to three or more antimicrobial drug classes. Further work is necessary to determine the source of the bacterial species found in the mussels.

Nested PCR Detection of Pythium sp. from Formalin-Fixed, Paraffin-Embedded Canine Tissue Sections.

Pythium insidiosum is an infectious oomycete affecting dogs that develop the cutaneous or gastrointestinal form of pythiosis with a poor prognosis. If left untreated, pythiosis may be fatal. This organism is not a true fungus because its cell wall and cell membrane lack chitin and ergosterol, respectively, requiring specific treatment. Identifying the organism is challenging, as a hematoxylin and eosin (H&E) stain poorly stain the P. insidiosum hyphae and cannot be differentiated conclusively from other fungal or fungal-like organisms (such as Lagenidium sp.) morphologically. Our study aimed to develop a nested PCR to detect P. insidiosum and compare it with the traditional histopathologic detection of hyphae. Formalin-fixed, paraffin-embedded (FFPE) tissue scrolls from 26 dogs with lesions suggesting the P. insidiosum infection were assessed histologically, and DNA was extracted from the FFPE tissue sections for nested PCR. Agreement between the histologic stains, (H&E), periodic acid-Schiff (PAS), and/or Grocott methenamine silver (GMS) and the nested PCR occurred in 18/26 cases. Hyphae consistent with Pythium sp. were identified via histopathology in 57.7% of the samples, whereas the nested PCR detected P. insidiosum in 76.9% of samples, aiding in the sensitivity of the diagnosis of pythiosis in dogs. Using this combination of techniques, we report 20 canine cases of pythiosis over 18 years in Indiana and Kentucky, an unexpectedly high incidence for temperate climatic regions. Using a combination of histopathology evaluation and nested PCR is recommended to aid in the accurate diagnosis of pythiosis.

Antimicrobial susceptibility and risk factors for resistance among Escherichia coli isolated from canine specimens submitted to a diagnostic laboratory in Indiana, 2010-2019.

Escherichia coli (E. coli) is the most common Gram-negative pathogen isolated in human infections. Antimicrobial resistant (AMR) E. coli originating from dogs may directly or indirectly cause disease in humans. The objective of this study was to calculate the proportion of antimicrobial susceptible E. coli isolated from canine specimens submitted to the Indiana Animal Disease Diagnostic Laboratory and to identify temporal patterns of susceptibility among these isolates. Susceptibility data of 2,738 E. coli isolates from dogs from 2010 through 2019 were used in this study. Proportions of isolates susceptible to the various antimicrobials were calculated using SAS statistical software and the Cochran-Armitage trend test was used to investigate the temporal trends in susceptibility. A multivariable binary logistic regression model was built to investigate the association between host factors and AMR. Overall, 553/2,738 (20.2%) of the isolates were susceptible to 17 of the 27 antimicrobials examined. Of the 2,638 isolates examined for amikacin susceptibility, 2,706 (97.5%) were susceptible, 2,657/2,673 (99.4%) isolates were susceptible to imipenem, and 2,099/2,670 (78.6%) were susceptible to marbofloxacin. A significant decreasing trend in susceptibility was observed for amoxicillin-clavulanic acid (P<0.0001), ampicillin (P<0.0001), Cefazolin (P<0.0001), ceftazidime (P = 0.0067), chloramphenicol (P<0.0001), and orbifloxacin (P = 0.008). The overall percentage of AMR isolates (isolates not susceptible to at least one antimicrobial) was 61.7% (1,690/2,738) and 29.3% (801/2,738) of isolates were multidrug resistant. Multivariable regression analyses showed significant associations between AMR and age (P = 0.0091), breed (P = 0.0008), and sample isolation site/source (P<0.0001). The decreasing trend in the proportion of isolates susceptible to several beta-lactam antimicrobials suggests that resistance of Escherichia coli in dogs to these antimicrobials could be increasing in Indiana. The decreasing trend in susceptibility to these drugs could be due to selection pressure from antimicrobial use.

Presumed acquired dynamic pectus excavatum in a cat.

An 11-year-old, spayed female American domestic shorthair cat was presented with open-mouth breathing and dyspnea due to respiratory tract disease. Radiographically, there was thickening of the retropharyngeal soft tissue and soft palate, focal pulmonary change, and severe pectus excavatum (PE), best seen on the left lateral view. Repeat thoracic radiographs 4 months later showed persistent PE, but only on the right lateral view; PE was absent on the left lateral view. The dynamic component of the observed PE was presumably acquired secondary to chronic upper respiratory disease and/or concurrent increased pliability of the thoracic wall from prolonged prednisolone treatment.

Pectus excavatum dynamique acquis présumé chez un chat. Une chatte domestique américaine stérilisée de 11 ans a présenté une respiration à bouche ouverte et une dyspnée due à une maladie des voies respiratoires. Radiographiquement, il y avait un épaississement des tissus mous rétropharyngés et du palais mou, une modification pulmonaire focale et un pectus excavatum (PE) sévère, mieux visible sur la vue latérale gauche. Des radiographies thoraciques répétées 4 mois plus tard ont montré une PE persistante, mais uniquement sur la vue latérale droite; la PE était absent sur la vue latérale gauche. La composante dynamique de la PE observée était vraisemblablement acquise secondaire à une maladie chronique des voies respiratoires supérieures et/ou à une flexibilité accrue concomitante de la paroi thoracique à la suite d'un traitement prolongé à la prednisolone.(Traduit par Dr Serge Messier).

Serologic investigation of exposure to influenza A virus H3N2 infection in dogs and cats in the United States.

We investigated, in a cross-sectional study, the prevalence of antibodies against canine influenza A virus (CIV) H3N2 in serum samples collected from dogs and cats using a commercial ELISA and a hemagglutination inhibition (HI) test. Samples were obtained from 519 cats and dogs from 13 states within the United States. Data were analyzed for potential risk factors with positive sera (vs. negative sera) by logistic regression. Odds ratios and their 95% confidence intervals (CIs) were calculated by exponentiation of the regression coefficients. Ten dogs (2.21%; 95% CI: 1.05-3.98%) and 6 cats (8.96%; 95% CI: 3.36-18.48%) tested seropositive for CIV H3N2 by HI. One feline sample (1.49%; 95% CI: 0.04-8.04%) and 16 canine samples (3.53%; 95% CI: 2.01-5.61%) tested seropositive by ELISA for influenza A virus. There were no apparent associations between seropositivity and putative risk factors. All positive animals were from Indiana or Illinois; however, CIV H3N2 seroprevalence was not common in Illinois and Indiana.

Detection of antibodies against Leptospira serovars via microscopic agglutination tests in dogs in the United States, 2000-2007.

OBJECTIVE: To use results of microscopic agglutination tests (MATs) conducted at a commercial veterinary diagnostic laboratory to determine temporal and demographic distributions of positive serologic test results for leptospirosis in dogs and identify correlations among results for various Leptospira serovars. DESIGN: Serosurvey. STUDY POPULATION: MAT results for 33,119 canine serum samples submitted to a commercial veterinary diagnostic laboratory from 2000 through 2007. PROCEDURES: Electronic records of MAT results for dogs were obtained from a veterinary diagnostic laboratory. Seropositivity for antibodies against Leptospira serovars was determined by use of a cutoff titer of >or=1:1,600 to reduce the possible impact of postvaccinal antibodies on results. Correlations between results for all possible pairs of serovars were calculated by ordinal ranking of positive (>or=1:100) antibody titer results. RESULTS: 2,680 samples (8.1%; 95% confidence interval [CI], 7.8% to 8.4%) were seropositive for antibodies against Leptospira serovars. The highest percentage of positive MAT results was for the year 2007 (10.2%; 95% CI, 9.5% to 10.9%) and for the months of November and December during the study period. Antibodies were most common against serovars Autumnalis, Grippotyphosa, Pomona, and Bratislava. Seroprevalence of leptospirosis was lowest for dogs>10 years of age but was similar across other age strata. CONCLUSIONS AND CLINICAL RELEVANCE: Leptospirosis can affect dogs of small and large breeds and various ages. Although an increase in proportions of positive MAT results was evident in the fall, monthly and annual variations suggested potential exposure in all months. Because of the limitations of MAT results and the limited number of serovars used in the test, bacterial culture should be used to identify infective Leptospira serovars.

Spatial and spatio-temporal clustering of overall and serovar-specific Leptospira microscopic agglutination test (MAT) seropositivity among dogs in the United States from 2000 through 2007.

Leptospirosis is a re-emerging disease of dogs in the United States (U.S.). This paper reports the findings of a retrospective study conducted to determine if seroreactivity to Leptospira microscopic agglutination test (MAT) among dogs in the U.S. clustered in space and time. The study utilized canine sera submitted to a commercial laboratory for leptospiral MAT from January 2000 through December 2007. There were 31,869 serum samples submitted by veterinarians from 3156 zip code locations across the U.S. Results of MAT were considered positive at titers of > or = 1:1600. Spatial and spatial-temporal scan statistics were used to identify statistically significant clusters of seroreactivity to Leptospira (overall and individual serovars) using recorded test request dates and locations of the centroid of the zip code reported for each serum sample. There were 2469 positive MAT results with a titer > or = 1:1600 to at least one of seven Leptospira serovars. Two relevant spatial clusters of 26.3 and 246.5 km radius were identified (P=0.001). The primary cluster was located in the northeastern part of Illinois including Chicago and surrounding areas (232 [14.4%] of 1612 MAT positive; RR=1.95). The secondary cluster covered the central part of Texas (292 [12.62%] of 2314 MAT positive; RR=1.71). Eight space-time clusters of overall MAT positivity were identified (29-335 km radius; P=0.001-0.048 and RR=3.98-24.69) that covered different geographic locations for different time points. Spatial and space-time clusters for individual serovars were also identified for six serovars: eight each of Grippotyphosa and Pomona, seven of Bratislava, five of Autumnalis, and three each of Icterohaemorrhagiae and Canicola. In conclusion Leptospira seropositivity in dogs tended to have distinctive clusters in space and space-time. Most of the space-time clusters of overall Leptospira MAT seropositivity were associated with cluster events for individual serovars. Further investigation is warranted to explain individual serovar clusters detected in this study, as a complex interaction of incidental host, environment and reservoir host may be responsible for the occurrence of these serovar clusters.

Adverse events after vaccine administration in cats: 2,560 cases (2002-2005).

OBJECTIVE: To determine the incidence of vaccine-associated adverse events (VAAEs) diagnosed within 30 days of vaccination in cats and characterize risk factors for their occurrence. DESIGN: Retrospective cohort study. ANIMALS: 496,189 cats vaccinated at 329 hospitals. PROCEDURES: Electronic records were searched for VAAEs that occurred after vaccine administration classified by practitioners as nonspecific vaccine reaction, allergic reaction, urticaria, shock, or anaphylaxis. Clinical signs and treatments were reviewed. The association between potential risk factors and a VAAE occurrence was estimated via multivariate logistic regression. RESULTS: 2,560 VAAEs were associated with administration of 1,258,712 doses of vaccine to 496,189 cats (51.6 VAAEs/10,000 cats vaccinated). The risk of a VAAE significantly increased as the number of vaccines administered per office visit increased. Risk was greatest for cats approximately 1 year old; overall risk was greater for neutered versus sexually intact cats. Lethargy with or without fever was the most commonly diagnosed VAAE. No localized reactions recorded in the 30-day period were subsequently diagnosed as neoplasia when followed for 1 to 2 years. CONCLUSIONS AND CLINICAL RELEVANCE: Although overall VAAE rates were low, young adult neutered cats that received multiple vaccines per office visit were at the greatest risk of a VAAE within 30 days after vaccination. Veterinarians should incorporate these findings into risk communications and limit the number of vaccinations administered concurrently to cats.

Canine leptospirosis, United States, 2002-2004.

The proportion of positive Leptospira microscopic agglutination tests for 23,005 dogs significantly increased from 2002 to 2004 (p < 0.002) regardless of the positive cutoff titer used and was highest (p < 0.05) for serovars Autumnalis and Grippotyphosa. The strongest positive serologic correlation (r = 0.72) was between serovars Autumnalis and Pomona.

Adverse events diagnosed within three days of vaccine administration in dogs.

OBJECTIVE: To determine incidence rates and potential risk factors for vaccine-associated adverse events (VAAEs) diagnosed within 3 days of administration in dogs. DESIGN: Retrospective cohort study. ANIMALS: 1,226,159 dogs vaccinated at 360 veterinary hospitals. PROCEDURE: Electronic records from January 1, 2002, through December 31, 2003, were searched for possible VAAEs (nonspecific vaccine reaction, allergic reaction, urticaria, or anaphylaxis) diagnosed within 3 days of vaccine administration. Information included age, weight, sex, neuter status, and breed. Specific clinical signs and treatments were reviewed in a random sample of 400 affected dogs. The association between potential risk factors and a VAAE was estimated by use of multivariate logistic regression. RESULTS: 4,678 adverse events (38.2/10,000 dogs vaccinated) were associated with administration of 3,439,576 doses of vaccine to 1,226,159 dogs. The VAAE rate decreased significantly as body weight increased. Risk was 27% to 38% greater for neutered versus sexually intact dogs and 35% to 64% greater for dogs approximately 1 to 3 years old versus 2 to 9 months old. The risk of a VAAE significantly increased as the number of vaccine doses administered per office visit increased; each additional vaccine significantly increased risk of an adverse event by 27% in dogs < or = 10 kg (22 lb) and 12% in dogs > 10 kg. CONCLUSIONS AND CLINICAL RELEVANCE: Young adult small-breed neutered dogs that received multiple vaccines per office visit were at greatest risk of a VAAE within 72 hours after vaccination. These factors should be considered in risk assessment and risk communication with clients regarding vaccination.

A space-time cluster of adverse events associated with canine rabies vaccine.

Electronic medical records of a large veterinary practice were used for surveillance of potential space-time clustering of adverse events associated with rabies vaccination in dogs. The study population was 257,564 dogs vaccinated in 169 hospitals in 13 US metropolitan areas during a 24-month period. Using a scan statistic for population rate data, significant space-time clusters were identified involving the Atlanta and Tampa/St. Petersburg areas during a 4-month period. Separate spatial-temporal analyses of these cities using coordinates for individual address coordinates identified one significant patient cluster (P=0.002), associated with a 23.26 km-radius area in Atlanta (20 adverse events in 702 dogs; 2.85%) from November 2002 through February 2003. This percentage of adverse events was significantly increased after adjustment for host-related factors and the number of concurrent vaccinations.

Serovar-specific prevalence and risk factors for leptospirosis among dogs: 90 cases (1997-2002).

OBJECTIVE: To estimate serovar-specific prevalence of leptospirosis by use of veterinary teaching hospital and laboratory submission data; describe annual and seasonal patterns of leptospirosis; and identify risk factors for age, sex, and breed. DESIGN: Retrospective study. ANIMALS: 90 dogs with leptospirosis. PROCEDURES: Hospital records of dogs examined at Purdue University Veterinary Teaching Hospital with a diagnosis of leptospirosis and laboratory records of dogs from which sera were tested for antibodies against Leptospira spp at Purdue University Animal Disease Diagnostic Laboratory from 1997 through 2002 were reviewed. The likely infecting Leptospira serovar was identified. Seasonal and annual prevalences were calculated by use of hospital population at risk (hospital cases) or serologic testing submissions (diagnostic laboratory cases). Age-, sex-, and breed-specific risk factors for hospital cases were estimated by odds ratios. RESULTS: Of the 39 hospitalized dogs identified, 34 had been serologically tested, and 22 of those were infected with Leptospira kirschneri serovar grippotyphosa. Of the 51 diagnostic laboratory cases, 59% had a reciprocal titer > or = 800 against serovar grippotyphosa. Diagnostic laboratory cases were more common in summer, whereas hospital cases of leptospirosis were more common in fall. Male dogs were at significantly greater risk of leptospirosis than female dogs; and dogs 4 to 6.9 years old were at significantly greater risk than dogs < 1 year old. CONCLUSIONS AND CLINICAL RELEVANCE: L kirschneri serovar grippotyphosa infection was associated with most cases of leptospirosis in dogs. Use of an effective vaccine that includes this serovar is advisable for dogs at risk of leptospirosis.

Evaluation of environmental risk factors for leptospirosis in dogs: 36 cases (1997-2002).

OBJECTIVE: To identify environmental risk factors for leptospirosis. DESIGN: Retrospective study. ANIMALS: 36 dogs with leptospirosis and 138 dogs seronegative for leptospirosis as determined by microscopic agglutination test for antibodies against Leptospira spp. PROCEDURES: Medical records of dogs evaluated for leptospirosis from 1997 though 2002 were identified. Owner address was used to geocode locations of dogs, and location-specific environmental risk factor data were obtained by use of a geographic information system. Risk of leptospirosis was estimated by odds ratios, controlling for potential confounding by dog age, sex, and breed. RESULTS: Leptospirosis in 19 of the 30 dogs in which an infecting Leptospira serovar could be identified was associated with Leptospira kirschneri serovar grippotyphosa infection. Dogs in which a diagnosis of leptospirosis was made, and dogs with leptospirosis caused by L kirschneri serovar grippotyphosa, were more likely to have addresses located in areas classified as rural in 1990 but urban in 2000. By use of information on recent urbanization and a logistic regression model, the status of 81.6% and 89.8% of dogs with leptospirosis and leptospirosis caused by serovar grippotyphosa, respectively, were correctly classified. Other environmental variables (proximity to streams, recreational areas, farmland, wetlands, areas subject to flooding, and areas with poor drainage; annual rainfall; and county cattle or pig population) did not significantly improve accuracy of classification. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs in periurban areas are at greater risk of leptospirosis. Vaccination of dogs in these areas to protect against leptospirosis should be considered.