A retrospective study on methicillin-resistant Staphylococcus spp. isolated from horses admitted to a Canadian veterinary teaching hospital between 2008 and 2018.

The goals of this retrospective study were to: determine the frequency of methicillin-resistant Staphylococcus spp. (MRS) isolated from horses admitted to an equine veterinary teaching hospital in Quebec from 2008 to 2018, investigate the patterns of antimicrobial resistance (AMR), and evaluate the distribution of MRS and methicillin-sensitive Staphyloccocus spp. (MSS) by body site. During this period, 311 Staphylococcus spp. were isolated from 273 horses and 127 of these isolates were submitted to antimicrobial susceptibility testing. Of these 127 isolates, 24 (18.9%) were MRS, and among the S. aureus (n = 76), 19 (25%) were MRS. The odds of detecting an MRS increased (25%) each year [95% confidence interval (CI) (1% to 55%), P = 0.039]. The highest frequencies of resistance were to tetracycline and gentamicin. Among the MRS isolates, 12% were susceptible to both tetracycline and gentamicin. The most frequently sampled body sites were "soft-tissues." There was no significant difference (P = 0.93) in the body site distribution of MRS and MSS isolates.

Étude rétrospective sur les Staphylococcus spp. résistants à la méthicilline isolés de chevaux admis à un hôpital d'enseignement vétérinaire au Canada entre 2008 et 2018. Les buts de cette étude rétrospective étaient : déterminer la fréquence de Staphylococcus spp. résistants à la méthicilline (MRS) isolés de chevaux admis à un hôpital d'enseignement vétérinaire au Québec entre 2008 et 2018, étudier les patrons de résistance aux antimicrobiens (AMR) et évalué la distribution de MRS et de Staphylococcus spp, sensible à la méthicilline (MSS) par site corporel. Durant la période visée, 311 Staphylococcus spp. furent isolés de 273 chevaux et 127 de ces isolats furent soumis à un test de sensibilité aux antimicrobiens. De ces 127 isolats, 24 (18,9 %) étaient de MRS, et parmi les S. aureus (n = 76), 19 (25 %) étaient des MRS. Les probabilités de détecter un MRS augmentaient (25 %) chaque année [intervalle de confiance 95 % (CI) (1 % à 55 %), P = 0,039]. Les fréquences les plus élevées de résistance étaient envers la tétracycline et la gentamycine. Parmi les isolats de MRS, 12 % étaient sensibles à la tétracycline et à la gentamycine. Les sites corporels les plus souvent échantillonnés étaient les « tissus mous ¼. Il n'y avait pas de différence significative (P = 0,93) entre les MRS et les MSS en ce qui a trait à la distribution selon les sites corporels.(Traduit par Dr Serge Messier).

A Disseminated Cryptococcus gattii VGIIa Infection in a Citron-Crested Cockatoo (Cacatua sulphurea citrinocristata) in Québec, Canada.

Cryptococcus gattii infection in mammals and birds has been confined historically to tropical and subtropical regions in Australia, Southeast Asia, Africa, and South America. Since the early 2000s, numerous reports describe the emergence of C. gattii on the Pacific Coast of North America. We report on a C. gattii infection in an 8-year-old male citron-crested cockatoo (Cacatua sulphurea citrinocristata) hatched on the Canadian Pacific Coast and raised in the province of Québec, Canada. The bird developed a slow growing ulcerated, fleshy, crusty, and hemorrhagic mass infiltrating the left lower rhamphotheca. Cryptococcus gattii infection was confirmed by cytologic examination of a fine needle aspirate of the mass, and results of fungal culture and sequencing. The genotype of the strain was determined to be VGIIa sequence type 20, the strongly overrepresented subgroup found on the Canadian Pacific coast. Minimum inhibitory concentrations for multiple antifungal drugs were determined. The bird received fluconazole but died acutely 55 days after initial presentation. Postmortem examination revealed a disseminated infection, with involvement of the beak, lungs, spleen, and brain.

Genetic structure of Mycobacterium avium subsp. paratuberculosis population in cattle herds in Quebec as revealed by using a combination of multilocus genomic analyses.

Mycobacterium avium subsp. paratuberculosis is the etiological agent of paratuberculosis, a granulomatous enteritis affecting a wide range of domestic and wild ruminants worldwide. A variety of molecular typing tools are used to distinguish M. avium subsp. paratuberculosis strains, contributing to a better understanding of M. avium subsp. paratuberculosis epidemiology. In the present study, PCR-based typing methods, including mycobacterial interspersed repetitive units/variable-number tandem repeats (MIRU-VNTR) and small sequence repeats (SSR) in addition to IS1311 PCR-restriction enzyme analysis (PCR-REA), were used to investigate the genetic heterogeneity of 200 M. avium subsp. paratuberculosis strains from dairy herds located in the province of Quebec, Canada. The majority of strains were of the "cattle type," or type II, although 3 strains were of the "bison type." A total of 38 genotypes, including a novel one, were identified using a combination of 17 genetic markers, which generated a Simpson's index of genetic diversity of 0.876. Additional analyses revealed no differences in genetic diversity between environmental and individual strains. Of note, a spatial and spatiotemporal cluster was evidenced regarding the distribution of one of the most common genotypes. The population had an overall homogeneous genetic structure, although a few strains stemmed out of the consensus cluster, including the bison-type strains. The genetic structure of M. avium subsp. paratuberculosis populations within most herds suggested intraherd dissemination and microevolution, although evidence of interherd contamination was also revealed. The level of genetic diversity obtained by combining MIRU-VNTR and SSR markers shows a promising avenue for molecular epidemiology investigations of M. avium subsp. paratuberculosis transmission patterns.

Comparison of 2 PCR assays on environmental samples cultured for Mycobacterium avium subsp. paratuberculosis.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of paratuberculosis, a chronic, contagious, and incurable enteric disease of ruminants. An in-house IS900 PCR assay validated for MAP detection in sheep has been shown to have a higher sensitivity than a commercial PCR and fecal culture. We have now compared the performance of this in-house IS900 PCR assay with a commercial ISMap02 PCR assay for the detection of MAP DNA in bovine dairy farm environmental samples. We purposefully selected 30 culture-positive, 62 culture-negative, and 62 non-interpretable environmental samples. We applied the IS900 PCR assay directly to the frozen inoculum of these samples. Inocula were incubated in an automated system, and growth was confirmed by an acid-fast bacilli stain and the IS900 PCR assay. Among culture-positive samples before incubation, the IS900 PCR assay yielded significantly more positive results than the ISMap02 PCR assay; however, among culture-negative samples, the IS900 PCR assay yielded positive results both before and after incubation. The ISMap02 PCR assay did not flag positively among the culture-negative samples either before or after incubation. The IS900 PCR assay is a sensitive method that can be used to detect MAP DNA in environmental samples before incubation. The ISMap02 PCR assay is a specific method used to detect MAP DNA in environmental samples both before and after incubation.

A retrospective study of 29 cases of otitis media/interna in dairy calves.

Epidemiological data, clinical findings, laboratory data, medical imaging, and outcomes were reviewed in 29 dairy calves with otitis media/interna. Age at admission ranged from 1 to 24 wk. The majority of calves were referred during winter. Clinical signs included drooping ear, ptosis, head tilt, abnormal nystagmus, strabismus, dysphagia, regurgitation, stiff neck, opisthotonos, facial hyperesthesia, and purulent aural discharge. Intranasal endoscopic examination of 5 animals revealed nasopharyngeal collapse in 4. Cerebrospinal fluid (CSF) was abnormal in all of 7 cases. Mycoplasma bovis was cultured from all but 1 case with external ear or tympanic bullae samples (n = 12), and Mycoplasma arginini was cultured from the remaining ear sample. Radiographs of the tympanic bullae were performed in 24 calves, tomodensitometry (CT) in 3 calves and ultrasound in 4 calves. According to medical imaging techniques or necropsy, 69% of the cases were classified as chronic. Mean duration of treatment was 23.3 d. The rate of clinical recovery was 75%.Epidemiological data, clinical findings, laboratory data, medical imaging, and outcomes were reviewed in 29 dairy calves with otitis media/interna. Age at admission ranged from 1 to 24 wk. The majority of calves were referred during winter. Clinical signs included drooping ear, ptosis, head tilt, abnormal nystagmus, strabismus, dysphagia, regurgitation, stiff neck, opisthotonos, facial hyperesthesia, and purulent aural discharge. Intranasal endoscopic examination of 5 animals revealed nasopharyngeal collapse in 4. Cerebrospinal fluid (CSF) was abnormal in all of 7 cases. Mycoplasma bovis was cultured from all but 1 case with external ear or tympanic bullae samples (n = 12), and Mycoplasma arginini was cultured from the remaining ear sample. Radiographs of the tympanic bullae were performed in 24 calves, tomodensitometry (CT) in 3 calves and ultrasound in 4 calves. According to medical imaging techniques or necropsy, 69% of the cases were classified as chronic. Mean duration of treatment was 23.3 d. The rate of clinical recovery was 75%.

RésuméÉtude rétrospective de 29 cas d'otite moyenne/interne chez les veaux laitiers. Les données épidémiologiques, les signes cliniques, les résultats de laboratoire et d'imagerie médicale et l'évolution de 29 veaux atteints d'otite moyenne/interne sont présentés. L'âge à la présentation variait de 1 à 24 semaines. La majorité des veaux ont été admis en hiver. Les signes cliniques incluaient une oreille tombante, une ptose de la paupière, une tête penchée, un nystagmus pathologique, un strabisme, de la dysphagie, des régurgitations, une raideur cervicale, de l'opisthotonos, de l'hyperesthésie faciale et une écoulements purulente de l'oreille. L'endoscopie des voies respiratoires supérieures a révélé un collapse du nasopharynx dans 4 cas sur 5. L'analyse du liquide céphalo-rachidien était anormale chez 7 veaux. Mycoplasma bovis a été isolé de tous les cas à partir d'échantillons d'oreille externe ou de bulle tympanique sauf 1 (n = 12) où Mycoplasma arginini a été isolé. La radiographie des bulles tympaniques a été réalisée sur 24 cas, la tomodensitométrie sur 3 cas et l'échographie sur 4 cas. Selon les techniques d'imagerie médicale ou la nécropsie, 69 % des cas étaient chroniques. La durée moyenne du traitement était de 23,3 jours. Le pronostic était de 75 %.(Traduit par les auteurs).

Nicoletella semolina in the airways of healthy horses and horses with severe asthma.

BACKGROUND: Nicoletella semolina was identified in the airways of horses and its low prevalence could be because of its difficult differentiation from other Pasteurellaceae. OBJECTIVES: To develop a molecular method for the identification of N. semolina and to evaluate its prevalence in the mouth and the airways of healthy and severe asthmatic horses. ANIMALS: Six healthy and 6 severely asthmatic horses in phase I, 10 severely asthmatic horses in phase II, and 10 healthy horses in phase III. METHODS: Cohort (phases I and II) and cross-sectional (phase III) studies. Quantitative polymerase chain reaction primers targeting the sodA gene were optimized. N. semolina was quantified in oral and nasal washes and in bronchoalveolar lavage fluid (BALF; phase I, sampled twice), in nasal washes and BALF (phase II, sampled twice), and in nasal washes (phase III). RESULTS: N. semolina was found in the nose of 5, 10, and 9 horses in phases I, II, and III, respectively (first sampling for phases I and II). Six BALF from 5 different horses were positive for N. semolina in phase II. In phase I, there was no significant difference in the nasal loads of healthy horses (median (range): 2.04 × 104 copies/mL (0-2.44 × 105 )) and asthmatic horses in exacerbation (3.75 × 102 (0-4.84 × 106 ); Wilcoxon's rank sum test, P = .57). CONCLUSIONS AND CLINICAL IMPORTANCE: N. semolina is commonly found in the airways of horses. The potential pathogenicity of N. semolina remains to be elucidated, but the molecular technique we developed will facilitate future studies.

Whole genome sequencing of methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolated from 4 horses in a veterinary teaching hospital and its ambulatory service.

Genomic characterization was conducted on 2 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from 2 horses hospitalized during an overlapping period of time and 2 methicillin-sensitive S. aureus (MSSA) strains isolated from 2 distinct horses. Phylogenetic proximity was traced and the genotypic and phenotypic characteristics of the antimicrobial resistance of the strains were compared. Whole genome sequencing of MRSA strains for this report was similar but differed from whole genome sequencing of MSSA strains. The MRSA strains were closely related, belonging to sequence type (ST) 612, spa type t1257, and SCCmec type IVd2B. The MSSA strains were also closely related, belonging to ST1660, spa type t3043, and having no detectable staphylococcal cassette chromosome mec elements. All MSRA and MSSA strains were Panton-Valentine leukocidin negative. There were discrepancies in the genotypic analysis and the antimicrobial susceptibility testing (phenotypic analysis) of MRSA strains for rifampin, trimethoprim-sulfamethoxazole, gentamicin, amikacin, and enrofloxacin.

La caractérisation génomique a été effectuée sur deux souches de Staphylococcus aureus résistantes à la méticilline (SARM) isolées de deux chevaux hospitalisés sur une période de chevauchement, et de deux S. aureus sensibles à la méticilline (SASM) isolés de deux chevaux distincts. Leur proximité phylogénétique a été retracée. Les caractéristiques génotypiques et phénotypiques de la résistance aux antimicrobiens de ces souches ont été comparées.Le séquençage complet du génome des souches de SARM pour ce rapport était similaire, mais différent du séquençage complet du génome des souches de SASM. Les souches de SARM étaient étroitement apparentées, appartenant à la séquence type (ST) 612, au spa type t1257 et au SCCmec type IVd2B. Les souches MSSA étaient étroitement apparentées appartenant au ST1660, spa type t3043 et aucun élément de la cassette contenant le gène mec n'a été détecté. Toutes les souches MSRA et MSSA étaient négatives pour la leucocidine Panton-Valentine. Il y avait des divergences entre l'analyse génotypique et les tests de sensibilité aux antimicrobiens (phénotype) des souches de SARM pour la rifampicine, le triméthoprime-sulfaméthoxazole, la gentamicine, l'amikacine et l'enrofloxacine.(Traduit par les auteurs).

Genomics accurately predicts antimicrobial resistance in Staphylococcus pseudintermedius collected as part of Vet-LIRN resistance monitoring.

Whole-genome sequencing (WGS) has changed our understanding of bacterial pathogens, aiding outbreak investigations and advancing our knowledge of their genetic features. However, there has been limited use of genomics to understand antimicrobial resistance of veterinary pathogens, which would help identify emerging resistance mechanisms and track their spread. The objectives of this study were to evaluate the correlation between resistance genotypes and phenotypes for Staphylococcus pseudintermedius, a major pathogen of companion animals, by comparing broth microdilution antimicrobial susceptibility testing and WGS. From 2017-2019, we conducted antimicrobial susceptibility testing and WGS on S. pseudintermedius isolates collected from dogs in the United States as a part of the Veterinary Laboratory Investigation and Response Network (Vet-LIRN) antimicrobial resistance monitoring program. Across thirteen antimicrobials in nine classes, resistance genotypes correlated with clinical resistance phenotypes 98.4 % of the time among a collection of 592 isolates. Our findings represent isolates from diverse lineages based on phylogenetic analyses, and these strong correlations are comparable to those from studies of several human pathogens such as Staphylococcus aureus and Salmonella enterica. We uncovered some important findings, including that 32.3 % of isolates had the mecA gene, which correlated with oxacillin resistance 97.0 % of the time. We also identified a novel rpoB mutation likely encoding rifampin resistance. These results show the value in using WGS to assess antimicrobial resistance in veterinary pathogens and to reveal putative new mechanisms of resistance.

Comparison of a closed system and an open system for blood collection in feline donors.

OBJECTIVES: This research aimed to evaluate the performance of a closed blood collection system and to compare it with an open system in terms of feasibility, tolerability by the donor, quality of blood collected and bacterial contamination. METHODS: Eight feline blood donors were prospectively and randomly subjected to both collection methods. Heart rate (HR), respiratory rate (RR) and blood pressure (BP) were evaluated before sedation, after sedation and after blood collection. The duration of the donation, the formation of a hematoma, and the degree of hemolysis and packed cell volume (PCV) of each blood unit were evaluated. Aliquot samples were aseptically collected from each unit and tested for bacterial contamination by culture and PCR on days 0, 14 and 28 of storage. RESULTS: There was no significant difference between collection methods for HR and RR at any time point. Before sedation, the mean systolic BP was significantly higher with the closed system (closed 169 mmHg, open 137 mmHg; P = 0.003). The average duration of collection was significantly shorter with the closed system (closed 3 mins 10 s, open 8 mins; P = 0.035); however, the prevalence of a successful blood collection with a single venipuncture and hematoma formation were not significantly different between systems. The mean unit PCV was significantly higher with the open system (closed 31%, open 34%; P = 0.026). On bacterial culture, 15/16 units were negative at all time points (closed 7; open 8). Using PCR, 5/16 units were positive for Ralstonia species for at least one time point (closed 3; open 2). CONCLUSIONS AND RELEVANCE: Our designed closed system appears to be well adapted to feline blood collection and was well tolerated by the donors, performing similarly to an open system, and could represent a valuable clinical device for the development of a feline blood bank, namely feline blood storage.

Clinical significance of Proteus mirabilis bacteriuria in dogs, risk factors and antimicrobial susceptibility.

The objectives of this study were to describe the in vitro antimicrobial susceptibility and clinical significance of Proteus mirabilis in canine bacteriuria and to identify the risk factors associated with P. mirabilis urinary tract infections. This is a retrospective observational study of 48 P. mirabilis-positive canine urinary cultures. Only 22 of the 48 P. mirabilis isolates (45.8%) were non-susceptible to at least one tested antimicrobial. Most P. mirabilis isolates (98%) were susceptible to enrofloxacin, 93.7% to amoxicillin/clavulanic acid, and 85.4% to ampicillin, cephalothin, and trimethoprim-sulfamethoxazole. Five multidrug-resistant isolates were detected (10.4%). A significant increase in antimicrobial resistance was observed over the study period. Positive P. mirabilis cultures were associated with bacterial cystitis in 36 of 39 dogs (92.3%), pyelonephritis in 2 of 39 dogs (5.1%), and one dog had both bacterial cystitis and pyelonephritis (2.5%). There was no subclinical bacteriuria. Most urinary tract infections were complicated as risk factors were identified in 37 of 39 dogs (94.8%). The most commonly identified risk factors were the presence of a contaminated peri-vulvar area with urine/feces or a hypoplastic vulva. To conclude, P. mirabilis bacteriuria was associated with upper and lower urinary tract infections in this study and was found more frequently in complicated bacterial cystitis. Multidrug-resistant isolates and increased P. mirabilis antimicrobial resistance have been identified over the last 10 years, but most isolates remain susceptible to first-line antimicrobials such as amoxicillin and trimethoprim-sulfamethoxazole.

Cette étude a pour but d'évaluer la sensibilité in vitro aux antibiotiques de Proteus mirabilis lors de bactériurie chez le chien, son importance clinique et les facteurs de risques d'infection urinaire associée à Proteus mirabilis. Il s'agit d'une étude rétrospective, observationnelle reposant sur 48 cultures urinaires positives à Proteus mirabilis chez le chien. Seuls 22 des 48 isolats (45,8 %) n'étaient pas sensibles à au moins un des antibiotiques testés. La majorité des isolats (98 %) étaient sensibles à l'enrofloxacine, 93,7 % à l'amoxicilline/acide clavulanique et 85,4 % à l'ampicilline, céphalothine et trimethoprime-sulfamethoxazole. Cinq isolats multi-résistants ont été détectés (10,4 %). Une augmentation significative de la résistance a été observée sur la période étudiée. Une cystite bactérienne a été diagnostiquée chez 36 des 39 chiens inclus (92,3 %), une pyélonéphrite chez deux chiens (5,1 %) et un chien présentait des signes de cystite bactérienne et de pyélonéphrite (2,5 %). Aucune bactériurie subclinique n'a été identifiée; la plupart des infections urinaires étaient compliquées (94,8 %). Les facteurs de risque les plus rencontrés sont la contamination de la région péri-vulvaire ou la présence d'une vulve hypoplasique. En conclusion, Proteus mirabilis doit être suspecté en cas de cystite bactérienne compliquée. Des isolats multi-résistants ont été identifiés et une hausse de la résistance a été observée au cours des dix dernières années. La plupart reste sensible aux antibiotiques de premières lignes que sont l'amoxicilline et trimethoprime-sulfamethoxazole.(Traduit par les auteurs).