Identification and antimicrobial susceptibility of coagulase positive staphylococci isolated from healthy dogs and dogs suffering from otitis externa

A total of 67 strains of coagulase positive staphylococci isolated from healthy dogs and dogs suffering from otitis externa were studied. Twenty-two isolates were from healthy dogs (five from hound dogs and 17 from companion dogs) and 45 from dogs suffering otitis externa (14 from hound dogs and 31 from companion dogs). Presumptive identification was attempted using the following tests: production of acetoin, anaerobic utilization of mannitol, acid production from mannitol, presence of beta-galactosidase, and growth on P agar supplemented with different concentrations of acriflavine. Susceptibility of staphylococci to 16 antibiotics was determined. Most effective antibiotics were imipenem, amoxycillin/clavulanic acid, ciprofloxacin, tobramycin, gentamicin and marbofloxacin. Penicillin, ampicillin and polymyxin B showed the lowest activity. There were no significant differences in antimicrobial susceptibility among isolates from healthy dogs and dogs suffering from otitis externa.     

Immune-mediated haemolytic anaemia in 110 dogs in Victoria, Australia

Objective   Evaluate the survival and prognostic indicators (i.e. breed predilection, season, blood transfusion, and the prevalence of autoagglutination) of dogs with immune-mediated haemolytic anaemia (IMHA) in Victoria, Australia.
Design   Retrospective study of 110 diagnosed with primary IMHA at the University of Melbourne Veterinary Clinic and Hospital.
Results   In total, 80 of the dogs (72.7%) were discharged from hospital and 48 of 65 (73.8%) dogs available for follow-up were known to be alive at 1 year, giving an overall 1-year survival of 48 (50.5%) of 95 dogs for which survival data were available. Regarding breed, 80 (18.2%) of the 110 dogs were Maltese-breed dogs compared with 81 (7.4%) of 1100 control dogs (P < 0.001). Springer Spaniels (P = 0.02), Hungarian Vizslas (P = 0.02) and Airedale Terriers (P < 0.001) were also over-represented compared with the control sample. There was no evidence of an association between the occurrence of IMHA in dogs and season in this study. Receiving one or more blood transfusions did not affect survival to the time of discharge from hospital. On initial blood smear examination, 57 (51.8%) of the 110 dogs had spontaneous autoagglutination and its presence was associated with decreased survival to discharge from hospital (P = 0.03). Packed cell volume, white cell count, platelet count and serum total bilirubin on admission had no effect on survival to the time of discharge from hospital or 1 year later.
Conclusion   Dogs with IMHA have a guarded prognosis as only half are still alive 1 year after the acute event.     

The antibiotic resistance of pathogenic staphylococci and streptococci isolated from dogs

The antibiotic resistance of strains of Staphylococcus aureus and beta–haemolytic streptococci of canine origin were assessed against eight drugs using the disc diffusion technique. Of 398 strains of Staph, aureus eight were resistant to neomycin, 15 to ampicillin, 23 to lincomycin, while of 87 streptococci, one was resistant to ampicillin, two to lincomycin and four to penicillin. In addition 4 of 340 Staph, aureus strains tested against cloxacillin were resistant.     

Antimicrobial resistance studies in staphylococci and streptococci isolated from cows with mastitis in Argentina

Background Staphylococcus aureus and Streptococcus agalactiae are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. Bacteria isolated from infected animals show increasing antimicrobial resistance.ObjectivesThis study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci.MethodsIsolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCCmec type and spa type were detected by the polymerase chain reaction method.ResultsWe isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as S. aureus. Among the 154 CNS, 24.6% (n = 38) were resistant to penicillin, 14.9% (n = 23) to erythromycin, 17.5% (n = 27) to clindamycin, 6.5% (n = 10) to cefoxitin and oxacillin. Among the S. aureus isolates, 16.1% (n = 5) were resistant to penicillin, 3.2% (n = 1) to cefoxitin and oxacillin (MRSA). Six MR isolates (5 CNS and 1 MRSA) were positive to the mecA gene, and presented the SCCmec IVa. The MRSA strain presented the sequence type 83 and the spa type 002. Among the 28 streptococcal isolates, 14.3% (n = 4) were resistant to penicillin, 10.7% (n = 3) to erythromycin and 14.3% (n = 4) to clindamycin.ConclusionsThe present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.     

Antimicrobial susceptibility of Staphylococcus intermedius isolated from healthy and diseased dogs

A total of 90 strains of Staphylococcus intermedius isolated from dogs were examined for antimicrobial susceptibility. There were no significant differences in the distribution patterns of MICs between strains from 1982 to 1985 and those from 1999, and between strains from healthy dogs and those from diseased dogs. All of the strains were susceptible to ABPC, DMPPC, CEX, TDM, ERFX, BFLX, and FF at concentrations of 0.05 to 6.25 microg/ml. The MICs of OTC, KM, EM, AIV-TS, and LCM were distributed in a broad range of 0.1 to >100 microg/ml, indicating the existence of resistant as well as susceptible populations of S. intermedius. Thirty-three strains (36.7%) were resistant to one or more anitmicrobial agents such as OTC (n=32), KM (n=9), EM (n=7), AIV-TS (n=7), and LCM (n=7).     

Comparative activity of pradofloxacin and marbofloxacin against coagulase‐positive staphylococci in a pharmacokinetic–pharmacodynamic model based on canine pharmacokinetics

Körber‐Irrgang, B., Wetzstein, H.‐G., Bagel‐Trah, S., Hafner, D., Kresken, M. Comparative activity of pradofloxacin and marbofloxacin against coagulase‐positive staphylococci in a pharmacokinetic–pharmacodynamic model based on canine pharmacokinetics. J. vet. Pharmacol. Therap.  35 , 571–579. Pradofloxacin (PRA), a novel veterinary 8‐cyano‐fluoroquinolone (FQ), is active against Staphylococcus pseudintermedius, the primary cause of canine pyoderma. An in vitro pharmacokinetic–pharmacodynamic model was used to compare the activities of PRA and marbofloxacin (MAR) against three clinical isolates of S. pseudintermedius and reference strain Staphylococcus aureus ATCC 6538. Experiments were performed involving populations of 10¹⁰ CFU corresponding to an inoculum density of approximately 5 × 10⁷ CFU/mL. The time course of free drug concentrations in canine serum was modelled, resulting from once daily standard oral dosing of 3 mg of PRA/kg and 2 mg of MAR/kg. In addition, experimentally high doses of 6 mg of PRA/kg and 16 mg of MAR/kg were tested against the least susceptible strain. Viable counts were monitored over 24 h. At concentrations associated with standard doses, PRA caused a faster and more sustained killing than MAR of all strains. The ratios of free drug under the concentration–time curve for 24 h over MIC and the maximum concentration of free drug over MIC were at least 90 and 26, and 8.5 and 2.1 for PRA and MAR, respectively. At experimentally high doses, PRA was superior to MAR in terms of immediate killing. Subpopulations with reduced susceptibility to either FQ did not emerge. We conclude that PRA is likely to be an efficacious therapy of canine staphylococcal infections.     

High hepatitis E virus antibody positive rates in dogs and humans exposed to dogs in the south‐west of China

Hepatitis E (HE) is a zoonotic viral disease caused by hepatitis E virus (HEV). The objective of this study was to investigate the prevalence of HEV infection among dogs and humans exposed to dogs in the south‐west region of China. A total of 4,490 dog serum samples and 2,206 relative practitioner serum samples were collected from 18 pet hospitals and dog farms in Yunnan, Sichuan and Guizhou province, and the anti‐HEV IgG antibodies were detected by ELISA. The results showed that the total positive rate of anti‐HEV antibodies was 36.55% with the highest rate in city stray dogs, and the differences in distinct species and growth phases were significant. The positive rate of anti‐HEV antibody in veterinarian and farm staff‐related practitioners was significantly higher than the general population. The finding of the present survey suggested that high HEV seroprevalence in dogs and humans exposed to dogs in the south‐west area of China poses a significant public health concern. It is urgent to improve integrated strategies to detect, prevent and control HEV infection in dogs and humans exposed to dogs in this area.     

Prevalence of antimicrobial-resistant staphylococci in nares and affected sites of pet dogs with superficial pyoderma

Currently, antimicrobial-resistant staphylococci, particularly methicillin-resistant Staphylococcus pseudintermedius (MRSP), are frequently isolated from canine superficial pyoderma in Japan. However, little is known regarding the nasal prevalence of MRSP in pet dogs. Here, we determined the prevalence of antimicrobial-resistant staphylococci in nares and affected sites of pet dogs with superficial pyoderma. Of the 125 nares and 108 affected sites of pet dogs with superficial pyoderma, 107 (13 species) and 110 (eight species) staphylococci strains, respectively, were isolated. The isolation rate of S. pseudintermedius from pyoderma sites (82/110 strains, 74.5%) was significantly higher than that from nares (57/107 strains, 53.3%) (P<0.01). Notably, the prevalence of MRSP (18/57 strains, 31.6%) in nares was equivalent to that in pyoderma sites (28/82 strains, 34.1%). Furthermore, the phenotypes and genotypes of antimicrobial resistance in MRSP strains from nares were similar to those from pyoderma sites. Our findings revealed that the prevalence of antimicrobial-resistant staphylococci in the nares of pet dogs with superficial pyoderma is the same level as that in affected sites. Therefore, considerable attention should be paid to the antimicrobial resistance of commensal staphylococci in companion animals.     

The anatomical distribution and antimicrobial susceptibility of yeast species isolated from healthy dogs

The aim of this work was to identify the predominant yeast species present at different anatomical sites in healthy dogs and to determine their in vitro antimicrobial susceptibility using a broth microdilution assay. Samples were collected from the preputial, vaginal, oral and perianal mucosae and the isolates cultured were identified according to their morphological characteristics and biochemical profile. Malassezia pachydermatis was the most commonly isolated yeast, followed by Candida parapsilosis, Candida tropicalis, Candida albicans, Saccharomyces cerevisiae and Rhodotorula spp.Minimum inhibitory concentrations of the azole derivatives ketoconazole, itraconazole and fluconazole against Candida spp. were 0.03–16 μg/mL, 0.06 to >16 μg/mL and 0.5–64 μg/mL, respectively and Candida isolates were sensitive to caspofungin and amphotericin B. Although all isolates of M. pachydermatis were sensitive to itraconazole, fluconazole, ketoconazole and amphotericin B, they were found to be resistant to caspofungin. The study has highlighted that Candida spp., M. pachydermatis, S. cerevisiae and Rhodotorula spp. are part of the normal canine surface microbiota and some of these organisms exhibit in vitro resistance to commonly used antimicrobials.     

宠物源大肠杆菌的血清型和毒力基因及耐药性调查

为研究宠物源致病性大肠杆菌(Escherichia coli)的血清型、毒力基因和耐药性之间的相关性,本研究由健康和患病犬、猫直肠拭子样品中分离177株E.coli,并采用玻片凝集法鉴定其血清型,结果显示分离株中定型菌株135株,分别属于20个不同的血清型,其中O1、O2和O8为主要的流行血清型。PCR方法检测11种毒力相关基因,并采用琼脂稀释法测定分离菌株对14种抗菌药的敏感性,结果表明3个血清型的菌株拥有相似的耐药表型,但毒力基因谱不同。62%的分离菌株携带fimH基因,并且毒力基因组合iroN+hlyF、iroN+fimH和traT+sitA比较流行。55%的O1血清型携带fimH基因,并且多数耐受四环素、多西环素、头孢噻吩和庆大霉素;20.8%的O2血清型菌株携带traT和sitA基因;50%的O8血清型携带traT和fimH基因。3个血清型分离菌株多数对安普霉素和阿米卡星敏感。     

Analysis of antibiotic resistance phenotypes and genes of Escherichia coli from healthy swine in Guizhou,China

This study was carried out to investigate the resistance phenotypes and resistance genes of Escherichia coli from swine in Guizhou, China. A total of 47 E. coli strains isolated between 2013 and 2018 were tested using the Kirby–Bauer (K–B) method to verify their resistance to 19 common clinical antimicrobials. Five classes consisting of 29 resistance genes were detected using polymerase chain reaction. The status regarding extended-spectrum β-lactamase (ESBL) and the relationship between ESBL CTX-M-type β-lactamase genes and plasmid-mediated quinolone resistance (PMQR) genes were analysed. A total of 46 strains (97.9%) were found to be multidrug resistant. Amongst them, 27 strains (57.4%) were resistant to more than eight antimicrobials, and the maximum number of resistant antimicrobial agents was 16. Twenty antibiotic resistance genes were detected, including six β-lactamase genes blaTEM (74.5%), blaCTX-M-9G (29.8%), blaDHA (17.0%), blaCTX-M-1G (10.6%), blaSHV (8.5%), blaOXA (2.1%), five aminoglycoside-modifying enzyme genes aac(3′)-IV (93.6%), aadA1 (78.7%), aadA2 (76.6%), aac(3′)-II c (55.3%), aac(6′)-Ib (2.1%) and five amphenicol resistance genes floR (70.2%), cmlA (53.2%), cat2 (10.6%), cat1 (6.4%), cmlB (2.1%), three PMQR genes qnrS (55.3%), oqxA (53.2%), qepA (27.7%) and polypeptide resistance gene mcr-1 (40.4%). The detection rate of ESBL-positive strains was 80.9% (38/47) and ESBL TEM-type was the most abundant ESBLs. The percentage of the PMQR gene in blaCTX-M-positive strains was high, and the detection rate of blaCTX-M-9G was the highest in CTX-M type. It is clear that multiple drug resistant E. coli is common in healthy swine in this study. Extended-spectrum β-lactamase is very abundant in the E. coli strains isolated from swine and most of them are multiple compound genotypes.     

Airway microbial culture and susceptibility patterns in dogs and cats with respiratory disease of varying severity

Objective – To compare airway microbiological culture and susceptibility results in 2 groups of dogs and cats: 1 with respiratory failure requiring positive pressure ventilation (PPV) and 1 with respiratory disease. Design – Retrospective study. Setting – University teaching hospital. Animals – Fifty‐two dogs and cats requiring PPV that had an airway microbiologic culture submitted from October 1, 2003 to October 31, 2008 were included. One hundred and four airway microbiologic cultures from dogs and cats with respiratory disease not requiring PPV were randomly sampled for comparison. Interventions – None. Measurements and Main Results – Patients with respiratory failure were more likely to have a gram‐negative enteric isolate identified (P<0.001), while patients with respiratory disease were more likely to have a gram‐negative nonenteric isolate (P<0.001) or anaerobic isolate (P<0.001) identified. Aerobic bacterial isolates from patients with respiratory failure were less likely to be susceptible to ampicillin (P=0.006), amoxicillin/clavulonate (P<0.001), chloramphenicol (P=0.004), enrofloxacin (P<0.001), ticarcillin/clavulonate (P=0.004), and the combination of ampicillin with enrofloxacin (P<0.001) than were aerobic bacterial isolates from patients with respiratory disease. Conclusions – Canine and feline patients with respiratory failure severe enough to require PPV exhibit a different pattern of bacterial isolates cultured from their airways when compared with isolates from patients with respiratory disease that has not resulted in ventilator dependence. These isolates are more likely to be resistant to commonly used antimicrobials/antimicrobial combinations than patients in the respiratory disease group. These findings suggest that in canine and feline patients with infectious lower respiratory tract disease, consideration of the severity of the pulmonary insult may allow for better prediction of likely isolates and their antimicrobial susceptibilities. Further prospective studies with a standardized collection technique are warranted.     

The antimicrobial susceptibility of Staphylococcus species isolated from canine dermatitis

In a retrospective study, 1538 strains of -haemolysin-producing Staphylococcus species isolated from dermatitis in dogs at three veterinary clinical microbiology laboratories in Norway during 1986–87 and 1993–94 were investigated for their antimicrobial susceptibility. None of the strains was resistant to cloxacillin, cephalexin or the quinolones enrofloxacin and ciprofloxacin. More than 96% of the strains were susceptible to trimethoprim-sulphonamide, bacitracin and fucidic acid. Between 67% and 89% of the strains were susceptible to erythromycin, lincosamides, tetracycline, neomycin and chloramphenicol. Only 37.9% of the strains were susceptible to penicillin. The frequency of penicillin resistance increased significantly between the first and second periods, from 46.0% to 58.6%. The frequency of resistance to lincomycin, clindamycin and erythromycin also increased significantly between the first and second periods, from 3.0%, 2.1% and 3.3% to 25.5%, 19.5% and 24.8%, respectively. A moderate increase in resistance to tetracycline was also noted, from 20.4% in the first to 27.6% in the second period. On the other hand, the frequency of resistance to trimethoprim-sulphonamide decreased significantly from 4.1% in the first to 0.9% in the second period. Many different resistance patterns were observed in each period. However, the proportion of multiresistant strains increased from 2.1% in the first to 10.2% in the second period. There was a decrease in resistance to the combination of trimethoprim-sulphonamide and penicillin from the first to the second period. Resistance to the combination of lincosamides and pencillin increased. For the combinations penicillin-tetracycline-lincosamides, pencillin-lincosamides-erythromycin, and pencillin-tetracycline-lincosamides-erythromycin, there was a striking increase in resistance between the first and the second periods.Abbreviations CVL Central Veterinary Laboratory - NCVM Norwegian College of Veterinary Medicine - NVL Norwegian Veterinary Laboratory     

Identification and antimicrobial susceptibility of bacteria and yeasts isolated from healthy dogs and dogs with otitis externa

The bacterial and fungal flora of the external ear canal of dogs with otitis externa and of healthy dogs were studied. The most frequently isolated microorganism from otitic ears was Staphylococcus intermedius (58.8%), followed by Malassezia pachydermatis (30.9%), Streptococcus canis (29.9%), Proteus spp. (14.4%) and Escherichia coli (10.3%). A statistical analysis of our results showed that the prevalence of these microorganisms is significant in dogs with otitis externa. Furthermore, the antimicrobial susceptibility patterns of isolated strains were determined. Majority of all bacterial isolates were most susceptible to gentamicin. Malassezia pachydermatis, the most prevalent yeast in this study, showed an excellent level of susceptibility to all antifungal agents tested.