Isolation and characterization of staphylococci from external auditory meatus of dogs with or without otitis externa with special reference to Staphylococcus schleiferi subsp. coagulans isolates

Whole Genome Sequencing and Comparative Genomics of Six Staphylococcus schleiferi and Staphylococcus coagulans Isolates

Staphylococcus schleiferi and Staphylococcus coagulans, closely related bacterial species within the Staphylococcus genus, present a challenge in classification and diagnosis due to their close genetic proximity and overlapping phenotypic features. Moreover, our understanding of the virulence mechanisms in staphylococcal species, beyond the extensively studied Staphylococcus aureus, remains limited, underscoring the importance of using comparative data to enhance our insights into virulence within these bacterial species. This study employed a comprehensive approach, utilizing comparative genomics, to identify genomic distinctions between S. schleiferi and S. coagulans, aiming to address the challenges in the accurate classification and diagnosis of these organisms and identify unique features. Whole genome sequencing was performed on six clinical isolates, and their genomes were compared to identify variations in gene content and virulence factors. De novo assembly and annotation revealed two samples as S. coagulans and four samples as S. schleiferi. Analysis of the core genomes revealed conserved regions crucial for defining species identity, while accessory genomic elements contained unique genes, possibly impacting the pathogenicity of the species.

Pseudomonas spp. in Canine Otitis Externa

Canine otitis externa (OE) is a commonly diagnosed condition seen in veterinary practice worldwide. In this review, we discuss the mechanisms of the disease, with a particular focus on the biological characteristics of Pseudomonas aeruginosa and the impact that antibiotic resistance has on successful recovery from OE. We also consider potential alternatives to antimicrobial chemotherapy for the treatment of recalcitrant infections. P. aeruginosa is not a typical constituent of the canine ear microbiota, but is frequently isolated from cases of chronic OE, and the nature of this pathogen often makes treatment difficult. Biofilm formation is identified in 40-95% of P. aeruginosa from cases of OE and intrinsic and acquired antibiotic resistance, especially resistance to clinically important antibiotics, highlights the need for alternative treatments. The role of other virulence factors in OE remains relatively unexplored and further work is needed. The studies described in this work highlight several potential alternative treatments, including the use of bacteriophages. This review provides a summary of the aetiology of OE with particular reference to the dysbiosis that leads to colonisation by P. aeruginosa and highlights the need for novel treatments for the future management of P. aeruginosa otitis.

Methicillin-resistant Staphylococcus schleiferi subspecies coagulans associated with otitis externa and pyoderma in dogs

Background:

Dermatological infections are the most common cases in the daily pet clinic. Since its discovery in 1990, Staphylococcus schleiferi subspecies coagulans have been reported more frequently in canine otitis externa and pyoderma and even in cases of zoonoses.

Aim:

Detect the presence of S. schleiferi subsp. coagulans of canine otitis externa and pyoderma, its antimicrobial resistance, and the presence of mecAgen.

Methods:

Three-hundred-thirty-one swabs from dogs with otitis externa and pyoderma were cultured on bacteriological agar for bacterial isolation and subsequent biochemical and molecular identification. The identified S. schleiferi subsp. coagulans were evaluated for their antimicrobial susceptibility using the Kirby–Bauer technique, including an oxacillin disk, and subsequently, a PCR was run to identify which ones had the mecA gene.

Results:

Thirty-four (22.97%) and twelve (6.56%) isolates were identified as S. schleiferi subspecies coagulans from otitis externa and pyoderma, respectively. Fluoroquinolones, the most widely used group of antibiotics in Peru, showed a susceptibility of 58.82% (20/34) in cases of otitis externa and 50% (6/12) in cases of canine pyoderma. Meanwhile, nitrofurantoin was the antibiotic with the best efficacy in both cases, with 97% (33/34) in otitis externa and 83% (10/12) in pyoderma. Furthermore, 40% (13/34) of S. schleiferi subsp. coagulans isolated from otitis externa were resistant to methicillin, and 85.29% (29/34) had the mecA gene. On the other hand, the only methicillin-resistant isolate from pyoderma was also the only one with a mecA gene.

Conclusion:

This study is the first report of S. schleiferi subsp. coagulans in Peru, finding a higher percentage than reported in other South American countries.

Genomic epidemiology of the opportunistic pathogen Staphylococcus coagulans from companion dogs

Introduction

Staphylococcus coagulans (formerly Staphylococcus schleiferi subsp. coagulans) is a common commensal and opportunistic pathogen of companion dogs. It carries a range of antimicrobial resistance genes and is an occasional zoonotic pathogen.

Hypothesis/Gap Statement

Despite the potential insight offered by genome sequencing into the biology of S. coagulans, few genomes are currently available for study.

Aim

To sequence and analyse S. coagulans genomes to improve understanding of this organism’s molecular epidemiology, antimicrobial resistance and bacterium–host interactions.

Methodology

Twenty-five genomes of clinical isolates collected at a veterinary referral hospital in Scotland, UK, were sequenced with Illumina technology. These genomes were analysed by a series of bioinformatics tools along with 16 previously sequenced genomes.

Results

Phylogenetic comparison of the 41 genomes shows that the current S. coagulans phylogeny is dominated by clades of closely related isolates, at least one of which has spread internationally. Ten of the 11 methicillin-resistant S. coagulans genomes in this collection of 41 encoded the mecA promoter and gene mutations that are predicted to render the isolates susceptible to penicillins in the presence of clavulanic acid, a feature only described to date in methicillin-resistant Staphylococcus aureus. Seven such isolates were from the current study and, in line with the genome-based prediction, all were susceptible to amoxicillin/clavulanic acid in vitro. S. coagulans shared very few highly conserved virulence-associated genes with Staphylococcus pseudintermedius, another common commensal and opportunistic canine pathogen.

Conclusion

The availability of a further 25 genome sequences from clinical S. coagulans isolates will aid in better understanding the epidemiology, bacterial–host interactions and antimicrobial resistance of this opportunistic pathogen.

Phenotypic and Molecular Traits of Staphylococcus coagulans Associated with Canine Skin Infections in Portugal

Staphylococcus coagulans is among the three most frequent pathogens of canine pyoderma. Yet, studies on this species are scarce. Twenty-seven S. coagulans and one S. schleiferi, corresponding to all pyoderma-related isolations from these two species at two veterinary laboratories in Lisbon, Portugal, between 1999 and 2018 (Lab 1) or 2018 (Lab 2), were analyzed. Isolates were identified by the analysis of the nuc gene and urease production. Antibiotic susceptibility towards 27 antibiotics was evaluated by disk diffusion. Fourteen antibiotic resistance genes were screened by PCR. Isolates were typed by SmaI-PFGE. Two S. coagulans isolates (2/27, 7.4%) were methicillin-resistant (MRSC, mecA+) and four (4/27, 14.8%) displayed a multidrug-resistant (MDR) phenotype. We observed resistance to penicillin (17/27, 63.0%), fluoroquinolones (11/27, 40.7%), erythromycin and clindamycin (3/27, 11.1%), fusidic acid (3/27, 11.1%) and tetracycline (1/27, 3.7%). The blaZ and erm(B) genes were carried by 16 and 1 isolates resistant to penicillin and erythromycin/clindamycin, respectively. Only three S. coagulans carried plasmids. The single S. schleiferi isolate presented an MDR phenotype. SmaI-PFGE revealed a limited genetic diversity of S. coagulans, with a predominant lineage present from 2001 to 2018. This study describes the first MRSC causing canine infection in Portugal and reveals a high burden of antimicrobial resistance, with the emergence of MDR phenotypes within the main lineages.

Isolation and genome sequencing of Staphylococcus schleiferi subspecies coagulans from Antarctic and North Sea seals

Reports on the commensal organism and opportunistic pathogen Staphylococcus schleiferi have largely considered isolates from humans and companion dogs. Two subspecies are recognized: the coagulase-negative S. schleiferi ssp. schleiferi, typically seen in humans, and the coagulase-positive S. schleiferi ssp. coagulans, typically seen in dogs. In this study, we report the isolation, genome sequencing and comparative genomics of three S. schleiferi ssp. coagulans isolates from mouth samples from two species of healthy, free-living Antarctic seals, southern elephant seals (Mirounga leonina) and Antarctic fur seals (Arctocephalus gazella), in the South Orkney Islands, Antarctica, and three isolates from post-mortem samples from grey seals (Halichoerus grypus) in Scotland, UK. This is the first report of S. schleiferi ssp. coagulans isolation from Antarctic fur seal and grey seal. The Antarctic fur seal represents the first isolation of S. schleiferi ssp. coagulans from the family Otariidae, while the grey seal represents the first isolation from a pinniped in the Northern Hemisphere. We compare seal, dog and human isolates from both S. schleiferi subspecies in the first genome-based phylogenetic analysis of the species.

Diagnostic evaluation of a point-of-care test for culture and microbial susceptibility testing in canine dermatological infections in clinical practice

Background and Aim

Empirical antimicrobial therapy is frequently given in superficial bacterial folliculitis (SBF) and otitis externa (OE) in dogs, especially for the initial clinical presentation. Culture and subsequent antimicrobial susceptibility testing (AST) are generally limited to chronic cases with poor response to initial therapy. Several factors contribute to the failure to implement the use of AST in veterinary practice, i.e., long laboratory turnaround time or special requirements for sample shipping. Point-of-care (PoC) testing might reduce laboratory turnaround time and costs and the risk of emergence of multidrug-resistant pathogens. This study evaluated the Speed Biogram™ PoC test in canine SBF and OE compared with conventional methods for culture and AST.

Materials and Methods

Thirty-four canine samples were analyzed: eleven from SBF, seven from bacterial OE, four from mixed OE, six from Malassezia spp. OE, and six negative controls. Sensitivity (Se) and specificity (Sp) of the PoC test and the agreement between the PoC test and conventional methods were evaluated.

Results

Se and Sp of PoC test in discriminating between healthy and unhealthy subjects were 100% (95% confidence interval [CI] 87.66-100.00) and 100% (95% CI 54.1-100.0), respectively. For bacterial identification, the k value was 0.532. Se and Sp of PoC tests for AST were 81.73% (95% CI 72.95-88.63) and 93.10% (95% CI 88.86-96.98), respectively with a total good agreement between tests (mean k=0.714), but major (8/27) and very major (19/27) errors were observed in 55% of bacterial conventional culture-positive samples.

Conclusion

PoC test can identify dogs with SBF and OE, but AST is not sufficiently accurate. The lack of susceptibility testing for methicillin makes this test inappropriate for use in small animal practice.

Evaluation of Oxacillin and Cefoxitin Disk Diffusion and MIC Breakpoints Established by the Clinical and Laboratory Standards Institute for Detection of mecA-Mediated Oxacillin Resistance in Staphylococcus schleiferi

Staphylococcus schleiferi is a beta-hemolytic, coagulase-variable colonizer of small animals that can cause opportunistic infections in humans. In veterinary isolates, the rate of mecA-mediated oxacillin resistance is significant, with reported resistance rates of >39%. The goal of this study was to evaluate oxacillin and cefoxitin disk diffusion (DD) and MIC breakpoints for detection of mecA-mediated oxacillin resistance in 52 human and 38 veterinary isolates of S. schleiferi Isolates were tested on multiple brands of commercial media and according to Clinical and Laboratory Standards Institute (CLSI) methods. Zone diameters and MIC values were interpreted using CLSI breakpoints (CLSI, Performance Standards for Antimicrobial Susceptibility Testing. M100-S27, 2017) for Staphylococcus aureus/Staphylococcus lugdunensis, coagulase-negative staphylococci (CoNS), and Staphylococcus pseudintermedius Results were compared to those of mecA PCR. Twenty-nine of 90 (32%) isolates were mecA positive. Oxacillin inhibition zone sizes and MICs interpreted by S. pseudintermedius breakpoints reliably differentiated mecA-positive and mecA-negative isolates, with a categorical agreement (CA) of 100% and no very major errors (VMEs) or major errors (MEs) for all media. For cefoxitin DD results interpreted using S. aureus/S. lugdunensis and CoNS breakpoints, CA values were 85% and 75%, respectively, and there were 72% and 64% VMEs, respectively, and 0 MEs. For cefoxitin MICs interpreted using S. aureus/S. lugdunensis breakpoints, CA was 81%, and there were 60% VMEs and no MEs. Our data demonstrate that oxacillin DD or MIC testing methods using the current S. pseudintermedius breakpoints reliably identify mecA-mediated oxacillin resistance in S. schleiferi, while cefoxitin DD and MIC testing methods perform poorly.

Antimicrobial resistance and characterisation of staphylococci isolated from healthy Labrador retrievers in the United Kingdom

BACKGROUND

Coagulase-positive (CoPS) and coagulase-negative (CoNS) staphylococci are normal commensals of the skin and mucosa, but are also opportunist pathogens. Meticillin-resistant (MR) and multidrug-resistant (MDR) isolates are increasing in human and veterinary healthcare. Healthy humans and other animals harbour a variety of staphylococci, including MR-CoPS and MR-CoNS. The main aims of the study were to characterise the population and antimicrobial resistance profiles of staphylococci from healthy non-vet visiting and non-antimicrobial treated Labrador retrievers in the UK.

RESULTS

Nasal and perineal samples were collected from 73 Labrador retrievers; staphylococci isolated and identified using phenotypic and biochemical methods. They were also confirmed by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS), PCR of the nuc gene and PCR and sequencing of the tuf gene. Disc diffusion and minimum inhibitory concentration (MIC) susceptibility tests were determined for a range of antimicrobials. In total, 102 CoPS (S. pseudintermedius n = 91, S. aureus n = 11) and 334 CoNS isolates were detected from 99% of dogs in this study. In 52% of dogs CoNS only were detected, with both CoNS and CoPS detected in 43% dogs and CoPS only detected in 4% of dogs. Antimicrobial resistance was not common among CoPS, but at least one MDR-CoNS isolate was detected in 34% of dogs. MR-CoNS were detected from 42% of dogs but no MR-CoPS were isolated. S. epidermidis (52% of dogs) was the most common CoNS found followed by S. warneri (30%) and S. equorum (27%), with another 15 CoNS species isolated from ≤ 15% of dogs. S. pseudintermedius and S. aureus were detected in 44% and 8% of dogs respectively.

CONCLUSIONS

MR- and MDR-CoPS were rare. However a high prevalence of MR- and MDR-CoNS were found in these dogs, even though they had no prior antimicrobial treatment or admission to veterinary premises. These findings are of concern due to the potential for opportunistic infections, zoonotic transmission and transmission of antimicrobial resistant determinants from these bacteria to coagulase positive staphylococci.

Prevalence of meticillin-resistant Staphylococcus pseudintermedius (MRSP) from skin and carriage sites of dogs after treatment of their meticillin-resistant or meticillin-sensitive staphylococcal pyoderma

BACKGROUND

Meticillin-resistant staphylococci are significant pathogens in veterinary dermatology, yet longitudinal studies of the impact of routine antimicrobial therapy on emergence or resolution of resistance are lacking.

OBJECTIVES

To determine the prevalence of meticillin-resistant staphylococci on skin and carriage sites in dogs with bacterial pyoderma and evaluate the prevalence of meticillin-resistant Staphylococcus pseudintermedius (MRSP) colonization after successful treatment of pyoderma.

ANIMALS

One hundred and seventy-three dogs that presented to a dermatology referral service with pyoderma and 41 healthy control dogs.

METHODS

Skin, nasal and rectal swabs for bacterial culture were collected at the time of referral and after clinical resolution of the pyoderma. Meticillin resistance was confirmed by demonstration of penicillin binding protein 2a antigen.

RESULTS

Initially, skin cultures yielded MRSP in 70 (40.5%) dogs, meticillin-resistant Staphylococcus aureus (MRSA) in three (1.7%) and meticillin-resistant Staphylococcus schleiferi ssp. coagulans (MRSScoag) in five (2.9%). Samples collected from the nose and rectum (carriage sites) yielded MRSP in 59 (34.1%) dogs, MRSA in 11 (6.4%) and MRSScoag in seven (4.0%). One hundred and two dogs were available for follow-up cultures after clinical cure. Of 42 dogs initially diagnosed with MRSP pyoderma, MRSP was isolated at follow-up from skin in 19 (45.2%) and carriage sites in 20 (47.6%). Of 60 dogs that did not have MRSP pyoderma initially, MRSP was isolated post-treatment from the skin in 17 (28.3%), and MRSP from carriage sites increased from 7.8% (initially) to 26.7% (P = 0.0022).

CONCLUSIONS AND CLINICAL IMPORTANCE

Colonization by MRSP often persists after resolution of MRSP pyoderma. Acquisition of MRSP during treatment appears to be common.

Genotypic relatedness and phenotypic characterization of Staphylococcus schleiferi subspecies in clinical samples from dogs

OBJECTIVE

To assess the degree of biological similarity (on the basis of genotype determined via pulsed-field gel electrophoresis [PFGE]) between isolates of 2 Staphylococcus schleiferi subspecies (S schleiferi subsp coagulans and S schleiferi subsp schleiferi) in clinical samples obtained from dogs.

SAMPLE POPULATION

161 S schleiferi isolates from 160 canine patients.

PROCEDURES

A commercial microbiology identification system was used to identify each isolate as S schleiferi. Isolates underwent slide and tube coagulase testing and antimicrobial susceptibility testing. A mecA PCR assay and a latex agglutination test for penicillin-binding protein 2a (PBP2a) were also performed on each isolate. Clonal clusters with a similarity cutoff value of 80% were identified via PFGE.

RESULTS

Of the 161 isolates, 61 (38%), 79 (49%), and 21 (13%) were obtained from cutaneous sites, ears, and other sites, respectively; 110 (68%) were coagulase negative, and 51 (32%) were coagulase positive. Among the coagulase-negative and coagulase-positive isolates, 65% (71/110) and 39% (20/51) were oxacillin resistant, respectively. All oxacillin-resistant isolates yielded positive results via mecA PCR assay and PBP2a latex agglutination testing. Via PFGE, 15 major clusters and 108 individual pulsed-field profiles were identified. Oxacillin-resistant and oxacillin-susceptible isolates clustered separately. Clonal clusters were heterogeneous and contained representatives of both subspecies.

CONCLUSIONS AND CLINICAL RELEVANCE

Coagulase-positive and coagulase-negative isolates were not genotypically distinct and may represent a single S schleiferi sp with variable coagulase production, rather than 2 biologically distinct subspecies. Further studies are needed to characterize clinical or epidemiological differences associated with infections with coagulase-positive and coagulase-negative S schleiferi in dogs.

FLUOROQUINOLONAS X RESISTÊNCIA BACTERIANA NA MEDICINA VETERINÁRIA

RESUMO As fluoroquinolonas são um grupo de substâncias químicas sintéticas com atividade antimicrobiana, com extensiva aplicação tanto na medicina humana como também na medicina veterinária, consideradas importantes armas no combate a organismos Gram-negativos, Grampositivos e as últimas gerações destes agentes antimicrobianos chegam a ser ativas contra as bactérias anaeróbias. Atualmente é uma das maiores classes de agentes antimicrobianos sendo utilizadas, mundialmente, no tratamento de infecções de origem bacteriana. As suas indicações terapêuticas evoluíram da aplicação em infecções urinárias a aplicações nas mais variadas infecções. Este grupo de fármacos foi se desenvolvendo de forma a ultrapassar grande parte das suas adversidades, possuindo hoje um espectro de ação bastante abrangente, boa disponibilidade oral, melhor difusão para os tecidos, uma meia vida maior e uma toxicidade consideravelmente reduzida. Esta revisão reúne informações atuais sobre as propriedades físico-químicas, farmacocinética, metabolismos de ação e de resistência das fluoroquinolonas de uso veterinário.

Multiplex-PCR method for species identification of coagulase-positive staphylococci

In veterinary medicine, coagulase-positive staphylococci (CoPS) other than Staphylococcus aureus have frequently been misidentified as being S. aureus strains, as they have several phenotypic traits in common. There has been no reliable method to distinguish among CoPS species in veterinary clinical laboratories. In the present study, we sequenced the thermonuclease (nuc) genes of staphylococcal species and devised a multiplex-PCR (M-PCR) method for species identification of CoPS by targeting the nuc gene locus. To evaluate sensitivity and specificity, we used this M-PCR method on 374 staphylococcal strains that had been previously identified to the species level by an hsp60 sequencing approach. We could successfully distinguish between S. aureus, S. hyicus, S. schleiferi, S. intermedius, S. pseudintermedius, and S. delphini groups A and B. The present method was both sensitive (99.8%) and specific (100%). Our M-PCR assay will allow the routine species identification of CoPS isolates from various animal species for clinical veterinary diagnosis.

Antimicrobial susceptibility of Staphylococcus intermedius and Staphylococcus schleiferi isolated from dogs

The susceptibility to 23 antimicrobial agents was determined in 114 isolates of Staphylococcus intermedius and eight isolates of Staphylococcus schleiferi of canine origin. Overall, 73% of S. intermedius isolates and 37.5% of S. schleiferi isolates were susceptible to all the 23 antimicrobials tested. The large majority of S. intermedius strains retained susceptibility to antimicrobials currently employed in treatment of pyoderma (cephalosporins, cotrimoxazole and association amoxicillin-clavulanic acid) as well as to those effective against staphylococci (fusidic acid, rifampicin and fluoroquinolones). Resistance in S. intermedius was observed mainly against macrolides, chloramphenicol and lincosamides, while S. schleiferi isolates retained susceptibility to all antimicrobials except three of six fluoroquinolones. Although, our results confirm susceptibility to antimicrobials currently employed in pyoderma treatment, the several different resistance patterns observed for S. intermedius emphasize the importance of antimicrobial susceptibility testing of canine staphylococci to choose the most appropriate treatment of infections and to allow the prudent use of antimicrobial drugs in companion animals.

High occurrence of multi-antimicrobial resistance in Staphylococcus intermedius isolates from healthy and diseased dogs and domesticated pigeons

Staphylococcus intermedius isolates (n=106), including 44 dog isolates and 62 pigeon isolates, were examined for their susceptibility to ampicillin, cephalexin, erythromycin, gentamicin, kanamycin, lincomycin, norfloxacin, oxacillin, tetracycline, and vancomycin by standard disk-diffusion test. The frequencies of resistance to ampicillin, kanamycin, and tetracycline were significantly higher in dog isolates than pigeon isolates (95.5% vs. 0%, 31.8% vs. 0%, and 45.5% vs. 9.7%, respectively; P<0.01). Antimicrobial resistance patterns of dog isolates and pigeon isolates were categorized respectively into nine and five distinct profiles. Significantly higher occurrence of resistance to two or more antimicrobials was observed in dog isolates than pigeon isolates (54.5% vs. 12.9%; P<0.01) and also in domesticated pigeon isolates than non-domesticated pigeon isolates (53.3% vs. 0%; P<0.01).

Antimicrobial susceptibility and mechanism of resistance to fluoroquinolones in Staphylococcus intermedius and Staphylococcus schleiferi

The objective of the present study was to determine the antimicrobial susceptibility of 136 canine isolates of Staphylococcus intermedius and 10 canine isolates of S. schleiferi subspecies coagulans to 16 fluoroquinolones (FQs), and to investigate the mechanisms of resistance in the nonsusceptible isolates. Of the 136 of S. intermedius tested 98.5% were susceptible to all 16 FQs whereas only 40% of the 10 isolates of S. schleiferi subspecies coagulans were susceptible. Two isolates of S. intermedius and six isolates of S. schleiferi, were found to be resistant to 13 out of 16 FQs, while they retained their susceptibility to fourth generation FQs such as gatifloxacin, moxifloxacin and trovafloxacin. Sequencing of the quinolone-resistance determining regions of gyrA and grlA genes showed that in S. intermedius, dichotomous resistance to FQs was associated with the occurrence of one alteration in GyrA-84 and one in GrlA-80, while in S. schleiferi the same pattern of resistance was observed in isolates showing these changes only in gyrA. This study is the first to screen FQs of the second, third and fourth generation for antimicrobial resistance in clinical isolates of S. intermedius and S. schleiferi of canine origin, and to describe mutations in gyrA and grlA associated with FQ resistance in these bacterial species.

Dissemination of the gene encoding exfoliative toxin of Staphylococcus intermedius among strains isolated from dogs during routine microbiological diagnostics

Phenotypic properties and species-specific PCR tests based on the nuc gene of Staphylococcus intermedius and S. aureus, and a conserved region of 16S rDNA were used to identify 45 S. intermedius and four S. aureus isolated from samples of dogs during routine diagnostics. Four S. pseudintermedius strains used for control purposes reacted positively with the S. intermedius nuc PCR showing the close relationship between both species. Investigating the 45 S. intermedius and four S. pseudintermedius strains for the prevalence of the exfoliative toxin SIET encoding gene yielded the presence of the gene for 21 of the S. intermedius and two of the S. pseudintermedius strains. Partial sequencing of the toxin gene of a single S. intermedius strain and comparing this sequence with that obtained from GenBank revealed an almost complete identity. The presence of the exfoliative toxin gene could mainly be found among S. intermedius isolated from skin and wound infections and from otitis externa possibly indicating a role of this toxin for the clinical symptoms.

Microbial Flora in the Ears of Healthy Experimental Beagles

There are studies of the microbial flora of the normal canine ear canal, but it is difficult to compare their results because the parts of the ear examined are not described, and various breeds of dogs were used. Therefore, we used only beagles to study the normal microbial flora in three parts of the ear: the pinna, the anthelix, and the vertical ear canal. The rates of bacterial isolation from the three parts were 91.8%, 70.5% and 48.8%, respectively. The corresponding rates of isolating yeasts was 48.8%, 81.4%, and 83.7%, respectively. These results show that the physiologic factors of the three parts of the ear from which the samples were obtained must be radically different.

Meningoencephalitis associated with Staphylococcus warneri in a dog

A case of meningoencephalitis in a dog caused by Staphylococcus warneri is reported here. The history and clinical signs were suggestive of possible central nervous system infection. Analysis of cerebrospinal fluid documented a neutrophilic pleocytosis (890 cells/mul) and the presence of occasional intracellular cocci. Staphylococcus warneri was isolated from the microbiological culture of the cerebrospinal fluid. Treatment consisted of intravenous antibiotics, supportive care and anticonvulsants for the generalised seizures that developed after admission. Histological assessment confirmed the location and extension of bacterial meningoencephalitis. Thrombotic meningoencephalitis associated with Staphylococcus warneri infection has not, to the authors' knowledge, been previously reported in dogs.

Identification of Staphylococcus hyicus by polymerase chain reaction mediated amplification of species specific sequences of superoxide dismutase A encoding gene sodA

A species specific PCR test, based on manganese-dependent superoxide dismutase A encoding gene sodA, was developed for the identification of Staphylococcus hyicus, an important bacterial pathogen in pigs. The designed primers allowed a rapid and reliable identification of phenotypically characterized S. hyicus, isolated in Russia, Germany and Denmark. No cross reactivities could be observed investigating staphylococcal reference strains representing 18 different species and subspecies. The use of the described primers might improve a future diagnosis of this bacterial pathogen.