Previous Antibiotic Exposure Reshapes the Population Structure of Infecting Uropathogenic Escherichia coli Strains by Selecting for Antibiotic Resistance over Urovirulence.

Antibiotic therapy is the standard of care for urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC). However, previous antibiotic therapy may impart a selective pressure that influences the population structure and pathogenic potential of infecting UPEC strains. Here, we conducted a 3-year study using whole-genome-sequencing analysis and retrospective medical record review to characterize how antibiotic exposure influenced the phenotypic antibiotic resistance, acquired resistome, virulome, and population structure of 88 UTI-causing E. coli strains from dogs. A majority of UTI-associated E. coli strains were from phylogroup B2 and clustered within sequence type 372. Previous antibiotic exposure was associated with a population shift toward UPEC from phylogroups other than the typical urovirulent phylogroup B2. The specific virulence profiles within the accessory virulome that were associated with antibiotic use were elicited by the effect of antibiotics on UPEC phylogenetic structure. Among phylogroup B2, antibiotic exposure increased the quantity of genes within the resistome and the odds of developing reduced susceptibility to at least one antibiotic. Non-B2 UPEC strains harbored a more diverse and greater resistome that conferred reduced susceptibility to multiple antibiotic classes following antibiotic exposure. Collectively, these data suggest that previous antibiotic exposure establishes an environment that provides a selective edge to non-B2 UPEC strains through their diverse and abundant antibiotic resistance genes, despite their lack of urovirulence genes. Our findings highlight the necessity for judicious use of antibiotics as we uncover another mechanism by which antibiotic exposure and resistance can influence the dynamics of bacterial infectious disease. IMPORTANCE Urinary tract infections (UTIs) are one of the most common infections of dogs and humans. While antibiotic therapy is the standard of care for UTIs and other infections, antibiotic exposure may influence the pathogenic profile of subsequent infections. We used whole-genome sequencing and retrospective medical record review to characterize the effect of systemic antibiotic therapy on the resistance, virulence, and population structure of 88 UTI-causing UPEC strains isolated from dogs. Our results indicate that antibiotic exposure alters the population structure of infecting UPEC strains, providing a selective edge for non-B2 phylogroups that harbor diverse and abundant resistance gene catalogues but fewer urovirulence genes. These findings highlight how antibiotic resistance can influence pathogen infection dynamics and have clinical implications for the judicious use of antibiotics for bacterial infections.

Pathogenomics and clinical recurrence influence biofilm capacity of Escherichia coli isolated from canine urinary tract infections.

Biofilm formation enhances bacteria's ability to colonize unique niches while protecting themselves from environmental stressors. Escherichia coli that colonize the urinary tract can protect themselves from the harsh bladder environment by forming biofilms. These biofilms promote persistence that can lead to chronic and recurrent urinary tract infections (UTI). While biofilm formation is frequently studied among urinary E. coli, its association with other pathogenic mechanisms and adaptations in certain host populations remains poorly understood. Here we utilized whole genome sequencing and retrospective medical record analysis to investigate associations between the population structure, phenotypic resistance, resistome, virulome, and patient demographic and clinical findings of 104 unique urinary E. coli and their capacity to form biofilms. We show that population structure including multilocus sequence typing and Clermont phylogrouping had no association with biofilm capacity. Among clinical factors, exposure to multiple antibiotics within that past 30 days and a clinical history of recurrent UTIs were positively associated with biofilm formation. In contrast, phenotypic antimicrobial reduced susceptibility and corresponding acquired resistance genes were negatively associated with biofilm formation. While biofilm formation was associated with increased virulence genes within the cumulative virulome, individual virulence genes did not influence biofilm capacity. We identified unique virulotypes among different strata of biofilm formation and associated the presence of the tosA/R-ibeA gene combination with moderate to strong biofilm formation. Our findings suggest that E. coli causing UTI in dogs utilize a heterogenous mixture of virulence genes to reach a biofilm phenotype, some of which may promote robust biofilm capacity. Antimicrobial use may select for two populations, non-biofilm formers that maintain an arsenal of antimicrobial resistance genes to nullify treatment and a second that forms durable biofilms to avoid therapeutic insults.

Longitudinal environmental Staphylococcus contamination in a new small animal veterinary hospital and utility of cleaning checklists.

Staphylococci are inhabitants of skin and mucous membranes with Staphylococcus pseudintermedius (SP) and Staphylococcus aureus (SA) serving as important pathogens for animals and people, respectively. Previous research has identified the environment as potentially important in hospital-associated infections and zoonotic transmission in veterinary settings. The objective of this pilot study was to determine the longitudinal prevalence over repeated samplings of environmental coagulase-positive Staphylococcus (CPS) in a new veterinary hospital and evaluate associations between contamination and environmental and clinical (caseload, cleaning checklists and staff numbers) factors. Cleaning and disinfection compliance, based on staff-completed checklists, were reviewed for the three shifts immediately prior to sampling. We hypothesized that over time, environmental contamination would increase as the clinic developed and caseload increased and compliance to cleaning checklists would decrease with increasing caseload. Over 18 months, 351 environmental samples were collected at five sampling times (sampling occurred before opening the hospital and every 3 to 6 months thereafter). Overall contamination with CPS was 30.8% (108/351), with SA (16.8%) and SP (13.1%) identified from the contaminated surfaces. Overall, methicillin-resistant strains (MRSA and MRSP) were infrequently recovered (combined n = 3; <1%). Point prevalence of CPS contamination was relatively stable over the study period (22.5%-28.4%), with the exception of an increase at the fourth sampling (52.9%). Cleaning compliance varied over the study period (57.9%-100%); the lowest reported cleaning coincided with the highest proportion of CPS contamination. The most commonly contaminated surfaces were chairs (7/15; 46.7%), examination tables (19/47; 40.4%) and computers (12/35; 34.3%); these items were infrequently included on cleaning lists. Surfaces not included in the checklist were 2.3 times more likely to be contaminated by CPS than those that were included (OR: 2.3, CI 95%: 1.02 -5.35, p-value=.04). MRSA and MRSP were rarely isolated from the environment in the newly opened hospital, indicating it may take time for resistant strains to enter the environment and persist on surfaces. This study identified the possible utility of cleaning checklists for directing cleaning practices and reducing the environmental contamination.

ß-Lactam and Fluoroquinolone-Resistant Enterobacteriaceae Recovered from the Environment of Human and Veterinary Tertiary Care Hospitals.

The dissemination of Enterobacteriaceae expressing resistance to clinically important antibiotics such as extended-spectrum cephalosporins (ESC), carbapenems, and fluoroquinolones is of critical concern to both human and veterinary medicine. In healthcare facilities, the movement of patients, personnel, and equipment provides an opportunity for Enterobacteriaceae carrying antibiotic resistance genes to disseminate in the hospital environment where they pose a threat to patients, staff, and hospital visitors. We collected environmental samples using electrostatic cloths to estimate the frequency of resistant Enterobacteriaceae contamination on human and veterinary hospital surfaces. Samples were enriched in nutrient broth modified with antibiotics to provide specific selection pressure to select for bacteria expressing AmpC ß-lactamase (blaCMY), extended-spectrum ß-lactamase (ESBL, blaCTX-M), carbapenemase, quinolone, and fluoroquinolone-resistant phenotypes. A total of 31 contact surfaces were sampled at each of five visits to two human hospitals. In addition, 34 surfaces were sampled at each of three visits to a veterinary hospital serving both farm animal and companion animal patients. Isolates expressing the blaCMY phenotype were recovered from 0.6%, 100%, and 18.2% of human hospitals, veterinary farm animal, and veterinary companion animal hospital surfaces, respectively. Isolates expressing the blaCTX-M phenotype were recovered from 0.6%, 55%, and 16.7% of human hospitals, farm animal, and companion animal veterinary hospital surfaces, respectively. Carbapenemase-producing Enterobacteriaceae (CPE) were detected from 1.3% of human hospital surfaces, but none were recovered from the veterinary hospital. Fluoroquinolone resistance was detected in 0.6%, 5.0%, and 37.9% of human hospitals, farm animal, and companion animal veterinary hospital surfaces, respectively. Our results indicate that ESC and fluoroquinolone-resistant Enterobacteriaceae can contaminate surfaces in both human and veterinary medical settings, with higher prevalence observed in veterinary hospitals, although the recovery of CPE from human hospital environments is concerning. Hospital medical trolleys or carts may serve as fomites for the dissemination of clinically relevant resistant bacteria.

Salmonella spp. and Extended-Spectrum Cephalosporin-Resistant Escherichia coli Frequently Contaminate Broiler Chicken Transport Cages of an Organic Production Company.

Antimicrobial resistant bacteria in retail meat pose a health hazard to the public, as does contamination of these products with Salmonella. Our aim was to determine the prevalence of Salmonella as well as Escherichia coli expressing AmpC and extended-spectrum beta-lactamase (ESBL) resistance phenotypes contaminating broiler transport cages and fresh, retail ground chicken meat. Sterile gauze sponges were used to collect duplicate cage floor samples from transport trailers that deliver market-ready birds to a single organic poultry-processing facility. With the exception of the first visit (n = 25), 50 duplicate cage floor samples were collected using moistened sterile gauze sponges on each of nine weekly visits during May, June, and July 2013. Additionally, fresh, retail ground chicken meat was sampled at each weekly visit from an on-site retail store located at the same processing facility. A total of 425 cage swabs and 72 ground chicken aliquots from 24 retail packages were collected and screened for the presence of Salmonella as well as E. coli expressing resistance to extended-spectrum cephalosporins using selective culture. We recovered Salmonella from 26.1% of cage swab samples and 2.8% of retail meat samples. E. coli expressing AmpC and ESBL resistance phenotypes were recovered from 84.9% and 22.6% of cage swabs and 77.8% and 11.1% of fresh, retail ground meat samples, respectively. Our results suggest that transport cages could potentially act as a source of broiler exposure to both Salmonella and enteric bacteria resistant to important antimicrobial drugs as they are transported for entry into the food supply as fresh, retail meat products.

High Prevalence of Multidrug-Resistant Community-Acquired Methicillin-Resistant Staphylococcus aureus at the Largest Veterinary Teaching Hospital in Costa Rica.

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen associated with severe infections in companion animals present in the community, and it is diagnosed in animals admitted to veterinary hospitals. However, reports that describe the circulation of MRSA in animal populations and veterinary settings in Latin America are scarce. Therefore, the objective of this study was to determine the prevalence and investigate the molecular epidemiology of MRSA in the environment of the largest veterinary teaching hospital in Costa Rica. Preselected contact surfaces were sampled twice within a 6-week period. Antimicrobial resistance, SCCmec type, Panton-Valentine leukocidin screening, USA type, and clonality were assessed in all recovered isolates. Overall, MRSA was isolated from 26.5% (27/102) of the surfaces sampled, with doors, desks, and examination tables most frequently contaminated. Molecular analysis demonstrated a variety of surfaces from different sections of the hospital contaminated by three highly related clones/pulsotypes. All, but one of the isolates were characterized as multidrug-resistant SCCmec type IV-USA700, a strain sporadically described in other countries and often classified as community acquired. The detection and frequency of this unique strain in this veterinary setting suggest Costa Rica has a distinctive MRSA ecology when compared with other countries/regions. The high level of environmental contamination highlights the necessity to establish and enforce standard cleaning and disinfection protocols to minimize further spread of this pathogen and reduce the risk of nosocomial and/or occupational transmission of MRSA.

Understanding the introduction and circulation of environmental methicillin-resistant Staphylococcus aureus in a large academic medical center during a nonoutbreak, year-long period.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of health care-associated infections, and the role that the hospital environment might play in the transmission cycle remains undefined. We determined the distribution of environmental MRSA isolates, studied contamination patterns of MRSA clones, and evaluated the association between MRSA patient load and environmental contamination. METHODS: High-contact surfaces were sampled for 12 consecutive months in 2 inpatient wards. Concurrently, aggregated data of MRSA patient infection burden were analyzed. Antimicrobial susceptibility testing and molecular epidemiologic tools were used to characterize and analyze all isolates. RESULTS: Overall, 23.7% of the surfaces were MRSA positive. Handrails (58.3%), the medicine room (50.0%), chart holders (41.7%), and access doors (33.3%) were the most contaminated surfaces. Thirty-four different MRSA pulsotypes were identified. Forty-six percent of the isolates were SCCmecII/USA100. Recurrent introduction and reintroduction of clones and hot spot surfaces frequently contaminated with different MRSA strains were observed. However, long-term contamination (maintenance) was not observed. The burden of clinical MRSA cases was not an indicator of the level of environmental contamination. CONCLUSIONS: MRSA frequently contaminates hospital surfaces during nonoutbreak periods and is not associated with the number of clinical MRSA cases. Monitoring and thorough cleaning and disinfection of hot spot surfaces are necessary to minimize the presence of MRSA in the hospital.

Outcomes of an Oral Care Protocol in Postmechanically Ventilated Patients.

BACKGROUND: Oral care is standard practice to prevent hospital-associated infections while patients are intubated and in the intensive care unit. Following extubation and transfer, infections remain an important risk for patients, but less attention is paid to oral care. Few studies have assessed the impact of oral care in recently extubated acutely ill patients. AIMS: To develop an evidence-based oral care protocol for hospitalized patients and determine the impact of this protocol on health outcomes in recently extubated patients. METHODS: In this randomized controlled trial, subjects were randomized to usual care or an intervention protocol that included tooth brushing, tongue scraping, flossing, mouth rinsing, and lip care. Major outcome measures were the revised THROAT (R-THROAT; oral cavity assessment) and overall prevalence of methicillin-sensitive Staphylococcus aureus and methicillin-resistant S. aureus on oral cultures. RESULTS: Seventy-four subjects were randomized. As measured by the R-THROAT, oral cavity health improved over time in both groups, but the intervention group demonstrated significantly more improvement than the control group (R-THROAT score improved by 1.97 intervention vs. 0.87 control; p = .04). Two categories, tongue and mouth comfort, demonstrated the most significant improvement. There was no difference in MSSA/MRSA colonization between the groups at the conclusion of the study. Overall, subjects in the intervention group were more satisfied with their protocol than subjects in the usual care group. LINKING EVIDENCE TO ACTION: This study offers an important evaluation of an oral care protocol after extubation. Results demonstrated improvement in the oral cavity assessment with the designed oral care protocol. Patients expressed a preference for the intervention protocol, which included a battery-operated toothbrush, higher-quality toothpaste and mouth rinse, tongue scraper, floss, and lip balm. The implementation of an oral care protocol specifically addressing patients in the immediate postintubation is essential.

Molecular and clinical characteristics of hospital and community onset methicillin-resistant Staphylococcus aureus strains associated with bloodstream infections.

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are classified epidemiologically as health care-associated hospital onset (HAHO)-, health care-associated community onset (HACO)-, or community-associated (CA)-MRSA. Clinical and molecular differences between HAHO- and HACO-MRSA BSI are not well known. Thus, we evaluated clinical and molecular characteristics of MRSA BSI to determine if distinct features are associated with HAHO- or HACO-MRSA strains. Molecular genotyping and medical record reviews were conducted on 282 MRSA BSI isolates from January 2007 to December 2009. MRSA classifications were 38% HAHO-, 54% HACO-, and 8% CA-MRSA. Comparing patients with HAHO-MRSA to those with HACO-MRSA, HAHO-MRSA patients had significantly higher rates of malignancy, surgery, recent invasive devices, and mortality and longer hospital stays. Patients with HACO-MRSA were more likely to have a history of renal failure, hemodialysis, residence in a long-term-care facility, long-term invasive devices, and higher rate of MRSA relapse. Distinct MRSA molecular strain differences also were seen between HAHO-MRSA (60% staphylococcal cassette chromosome mec type II [SCCmec II], 30% SCCmec III, and 9% SCCmec IV) and HACO-MRSA (47% SCCmec II, 35% SCCmec III, and 16% SCCmec IV) (P < 0.001). In summary, our study reveals significant clinical and molecular differences between patients with HAHO- and HACO-MRSA BSI. In order to decrease rates of MRSA infection, preventive efforts need to be directed toward patients in the community with health care-associated risk factors in addition to inpatient infection control.

Methicillin-resistant Staphylococcus aureus in public transportation vehicles (buses): another piece to the epidemiologic puzzle.

BACKGROUND: Little is known about the occurrence and epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in public transportation in the United States. This research sought to determine the background prevalence and phenotypic and genotypic characteristics of MRSA strains circulating on buses from a large, metropolitan transportation agency. METHODS: Electrostatic wipes were used to collect 237 surface samples from 40 buses randomly selected from July-October 2010. Six samples were collected from each bus immediately postservice and before any cleaning and disinfection. Positive isolates were analyzed for antibiotic resistance, staphylococcal cassette chromosome mec (SCCmec) type, and pulsed-field gel electrophoresis; and potential epidemiologic factors were examined. RESULTS: Of the buses, 68% (27/40) were contaminated with S aureus, and 63% (25/40) were contaminated with MRSA. Seats and seat rails were the surfaces most frequently contaminated, followed by the back door and stanchions. Most (62.9%) of the MRSA isolates were classified as community-associated MRSA clones (SCCmec type IV), and 22.9% were health care-associated MRSA clones (SCCmec type II). Of the MRSA strains, 65% (5/20) were multidrug resistant. CONCLUSION: MRSA was frequently isolated from commonly touched surfaces in buses serving both hospital and community routes. Phenotypic and genotypic analysis demonstrated that buses may be effective mixing vessels for MRSA strains of both community and health care-associated origin.

Molecular epidemiology of environmental MRSA at an equine teaching hospital: introduction, circulation and maintenance.

The role that environmental contamination might play as a reservoir and a possible source of Methicillin-resistant Staphylococcus aureus (MRSA) for patients and personnel at equine veterinary hospitals remains undefined, as the environment has only been monitored during outbreaks or for short periods. Therefore, the objectives of this study were to determine the monthly presence, distribution, and characteristics of environmental MRSA at an equine hospital, and to establish patterns of contamination over time using molecular epidemiological analyses. For this purpose, a yearlong active MRSA surveillance was performed targeting the environment and incoming patients. Antimicrobial susceptibility testing, SCCmec typing, PFGE typing, and dendrographic analysis were used to characterize and analyze these isolates. Overall, 8.6% of the surfaces and 5.8% of the horses sampled were positive for MRSA. The most common contaminated surfaces were: computers, feed-water buckets, and surgery tables-mats. Ninety percent of the isolates carried SCCmec type IV, and 62.0% were classified as USA500. Molecular analysis showed that new pulsotypes were constantly introduced into the hospital throughout the year. However, maintenance of strains in the environment was also observed when unique clones were detected for 2 consecutive months on the same surfaces. Additionally, pulsotypes were circulating throughout several areas and different contact surfaces of the hospital. Based on these results, it is evident that MRSA is constantly introduced and frequently found in the equine hospital environment, and that some contact surfaces could act as "hot-spots". These contaminated surfaces should be actively targeted for strict cleaning and disinfection as well as regular monitoring.

Screening and characterization of Staphylococcus aureus from ophthalmology clinic surfaces: a proposed surveillance tool.

PURPOSE: To screen environmental surfaces of an outpatient ophthalmic clinic for methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA); to identify the most commonly contaminated surfaces and to phenotype and genotype all collected isolates. DESIGN: A single institution, 1-year prospective environmental study. METHODS: Commonly touched surfaces in examination rooms and common areas were targeted and sampled on a quarterly basis for 1 year. Samples were collected using electrostatic cloths and swabs. S. aureus was isolated using nonselective and selective media. Morphologic characteristics and standard biologic testing were used to confirm staphylococcal species. S. aureus isolates were phenotypically (Kirby-Bauer method) and genotypically characterized (mecA confirmation, SCCmec typing and pulsed-field gel electrophoresis). Dendrogram analysis was used to establish genetic relatedness between the isolates. RESULTS: Of 112 total samples, 27 (24%) and 5 (4%) were MSSA- and MRSA-positive, respectively. Both community-associated (SCCmec IV, USA300) and hospital-associated (SCCmec II, USA100) MRSA isolates were found. No single surface remained consistently positive with the same isolate over time, and molecular analysis demonstrated high levels of diversity among isolates. Doorknobs, slit-lamp headrests and chinrests, and computer keyboards were commonly found to be contaminated. CONCLUSIONS: The proposed surveillance protocol successfully allowed the detection of both MSSA and MRSA contaminating important high-touch surfaces in a representative ophthalmology clinic. Frequently contaminated surfaces must be targeted for routine cleaning and disinfection because there is a constant introduction of clones over time. Hence, other clinics may consider implementing and adapting surveillance tools, like the one described here, to help them control these important nosocomial pathogens.

Epidemiological profiling of methicillin-resistant Staphylococcus aureus-positive dogs arriving at a veterinary teaching hospital.

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important zoonotic and nosocomial pathogen in veterinary settings. Even though human risk factors for MRSA infection and colonization are well known, this information in animals is lacking. The objective of this study was to identify risk factors associated with MRSA carrier dogs on their arrival at a veterinary teaching hospital. A total of 435 dogs were enrolled in the MRSA active surveillance program at The Ohio State University-Veterinary Medical Center over a 1-year period. Dogs were screened for MRSA on arrival, regardless of health status, sex, breed, or age. In addition, an epidemiological survey and medical history were obtained for each dog to identify potential risk factors up to 1 year prior to the appointment. Of 435 dogs included in the study, 25 (5.7%) were MRSA positive, with 86.5% of the isolates classified staphylococcal chromosome cassette mec (SCCmec) type II and USA100. Four of the 25 MRSA carrier dogs were healthy, 20 had health issues unrelated to MRSA, and 1 had an active MRSA infection. MRSA was detected in the nares (72%, 18/25), skin lesions (24%, 6/25), and the perianal area (16%, 4/25). Except for previous surgery <90 days (odds ratio [OR]=4.9; 95% confidence interval [CI] 1.4-17.6; p value 0.01), none of the variables related to the previous medical history, dog's management, home environment, and other potential exposures were associated with the MRSA carrier status. However, the profession of the owner was significantly associated, and dogs owned by veterinary students were 20.5 times (95% CI 4.5-93.6; p value≤0.01) more likely to be MRSA positive than dogs owned by clients with different occupations. MRSA-positive dogs were dispersed in different categories, preventing the creation of an epidemiological profile that would allow their early recognition upon arrival to a veterinary hospital. However, the association between veterinary students with MRSA-positive dogs is a concern that deserves further evaluation.

Presence, distribution, and molecular epidemiology of methicillin-resistant Staphylococcus aureus in a small animal teaching hospital: a year-long active surveillance targeting dogs and their environment.

Methicillin-resistant Staphylococcus aureus (MRSA) is known to be present in small animal veterinary clinical environments. However, a better understanding of the ecology and dynamics of MRSA in these environments is necessary for the development of effective infectious disease prevention and control programs. To achieve this goal, a yearlong active MRSA surveillance program was established at The Ohio State University (OSU) Veterinary Medical Center to describe the spatial and molecular epidemiology of this bacterium in the small animal hospital. Antimicrobial susceptibility testing, staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE) typing, and dendrogram analysis were used to characterize and analyze the 81 environmental and 37 canine-origin MRSA isolates obtained during monthly sampling events. Overall, 13.5% of surfaces were contaminated with MRSA at 1 or more sampling times throughout the year. The majority of the environmental and canine isolates were SCCmec type II (93.8% and 86.5%, respectively) and USA100 (90.1% and 86.5%, respectively). By PFGE analysis, these isolates were found to be closely related, which reflects a low diversity of MRSA strains circulating in the hospital. For 5 consecutive months, 1 unique pulsotype was the most prevalent across the medical services and was recovered from a variety of surfaces and hospital locations. Carts/gurneys, doors, and examination tables/floors were the most frequently contaminated surfaces. Some surfaces maintained the same pulsotypes for 3 consecutive months. Molecular analysis found that incoming MRSA-positive dogs were capable of introducing a new pulsotype into the hospital environment during the surveillance period. Our results suggest that once a MRSA strain is introduced into the hospital environment, it can be maintained and spread for extended periods of time. These findings can aid in the development of biosecurity and biocontainment protocols aimed at reducing environmental contamination and potential exposures to MRSA in veterinary hospital staff, clients, and patients.

Antimicrobial drug use in dogs prior to admission to a veterinary teaching hospital.

OBJECTIVE: To determine frequency of antimicrobial drug (AMD) use in dogs within 12 months prior to admission to a veterinary teaching hospital. DESIGN: Owner survey and medical records review. ANIMALS: 435 dogs admitted to a veterinary teaching hospital. PROCEDURES: Demographic characteristics and information regarding AMD use in dogs were obtained from medical records and results of surveys completed by owners of dogs. RESULTS: 242 (55.6%) dogs received at least 1 AMD within 12 months prior to hospital admission; 125 (51.7%) of these dogs had a disease of the integument at the time of admission. ß-Lactam AMDs were used more frequently than AMDs of any other class (176/242 [72.7%] dogs). Three hundred sixty-eight dogs had a medical problem at the time of hospital admission; 225 (61.1%) of these dogs had received at least 1 AMD within 12 months prior to hospital admission. Dogs referred by a veterinarian to the hospital were 2.39 times as likely to have received at least 1 AMD within 30 days prior to hospital admission as were dogs admitted without a referral. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated AMDs were frequently administered to dogs prior to admission to the teaching hospital. Use of AMDs in animals could be a risk factor for coselection and spread of multidrug-resistant pathogens, and colonization or infection of dogs with such pathogens could have a negative impact on the health of other animals and humans.

Análisis retrospectivo de las pruebas diagnósticas de leptospirosis bovina procesadas en la unidad de investigación y diagnóstico de leptospirosis de la Universidad del Zulia 1998-2001 / Retrospective analysis of bovine leptospirosis diagnostic tests performered at the research and diagnosis unit of leptospirosis of Zulia University 1998-2001

En el presente estudio se analizaron los resultados de sueros de bovinos procesados en la Unidad de Investigación y Diagnóstico de Leptospirosis de la Universidad del Zulia durante el período 1998-2001. De un total de 819 muestras provenientes de la región occidental de Venezuela, procesadas mediante la Técnica de Microaglutinación (MAT), se observó que 38 por ciento animales fueron seropositivos a uno o más serovares. Los serovares icterohaemorrhagiae (49 por ciento), hardjo (45 por ciento) y hebdomadis (44 por ciento) fueron los más frecuentes, sin evidenciar diferencias estadísticamente significativas entre si. En cuanto a la vacunación, se observó un 56 por ciento de seropositividad en animales no vacunados y 26 por ciento en animales vacunados. En relación a la edad, se obtuvo un 46 por ciento de seropositividad en animales mayores de 48 meses de edad, 35 por ciento en animales entre 12 y 48 meses de edad y 100 por ciento en bovinos menores de 12 meses de edad. De 270 animales con registros clínicos completos, 99 por ciento reportaron abortos como signo clínico más relevante, de los cuales el 49 por ciento fueron realmente positivos a leptospirosis. Se concluye que L. icterohaemorrhagiae y L. hardjo, fueron los serovares que circularon mayormente en el ganado bovino en la región occidental de Venezuela desde 1998 hasta 2001, siendo asociados en varias oportunidades a problemas abortivos. También se observó que los animales no vacunados presentaron una mayor seropositividad que los vacunados. Este estudio permitirá establecer una línea base para comparar las seroprevalencias actuales y futuras de la leptospirosis bovina en esta región, aportando información epidemiológica importante que permita el mejoramiento de medidas de prevención y control en contra de esta enfermedad.

Results from bovine serum samples processed at the Unit of Investigation and Diagnose of Leptospirosis of Zulia University, during the period 1998-2001 were analyzed in the present study. From a total of 819 samples submitted across the Western region in Venezuela, 38 percent were positive to one or more serovars by the Microagglutination Test (MAT). The most frequent serovars observed were icterohaemorrhagiae (49 percent), hardjo (45 percent) and hebdomadis (44 percent), however, no statistical significant differences were found between them. In regards to vaccination, 56 percent of the non-vaccinated animals and 26 percent of the vaccinated were seropositive. The age distribution showed that 46 percent of the animals older than 48 months, 35 percent of the animals between 12 and 48 months-old, and 100 percent of the animals younger than 12 months-old were positive to leptospira. From 270 animals with complete clinical records, 99 percent reported abortion as the main clinical sign, and 49 percent of them were indeed positives to leptospirosis. In conclusion, L. icterohaemorrhagiae and L. hardjo were the most common serovars circulating in the cattle population in the Western region in Venezuela between 1998 and 2001, in which several cases were associated with reproductive problems. It was also observed that non-vaccinated animals presented a higher seropositivity than animals that were vaccinated. This study will allow the establishment of a baseline to compare present and future studies on Bovine Leptospirosis in this region, providing important epidemiological information to be used in improving preventive and control measures against this disease.