Cheol-Yong Hwang

Prevalence of Bartonella henselae and Bartonella clarridgeiae in cats and dogs in Korea.

Blood, saliva, and nail samples were collected from 54 dogs and 151 cats and analyzed for the presence of Bartonella henselae with a novel nested polymerase chain reaction (PCR) method. Bartonella (B.) henselae was detected in feral cat blood (41.8%), saliva (44.1%), and nail (42.7%) samples. B. henselae was also detected in pet cat blood (33.3%), saliva (43.5%), and nail (29.5%) samples and in pet dog blood (16.6%), saliva (18.5%), and nail (29.6%) samples. Nine samples were infected with B. clarridgeiae and 2 were co-infected with B. henselae and B. clarridgeiae of blood samples of dogs. This report is the first to investigate the prevalence of B. henselae and B. clarridgeiae in dogs and cats in Korea, and suggests that dogs and cats may serve as potential Bartonella reservoirs.

Zonisamide monotherapy for idiopathic epilepsy in dogs

Abstract AIM: To evaluate the efficacy of zonisamide as a monotherapy in dogs with idiopathic epileptic seizure. METHODS: The experiment was conducted on 10 dogs with idiopathic epilepsy that were treated at the Seoul National University Hospital for Animals. A diagnosis was conducted based on physical and neurologic examination, complete blood count and chemical analysis, magnetic resonance imaging and cerebrospinal fluid analyses. Idiopathic epilepsy was diagnosed when all of these examinations were normal. Oral zonisamide was administrated to 10 dogs with idiopathic epilepsy at 5–15 mg/kg per os every 12 h to achieve a concentration of zonisamide in serum of 10–40 μg/mL. The frequency of seizures before and after the administration of zonisamide therapy was recorded and the concentrations of zonisamide in serum were measured. RESULTS: Six (60%) of the dogs were favourable responders to treatment, showing a ≥50% reduction in monthly frequency of seizures. Of the remaining four, two dogs did not show a reduction and the other two showed an increase in frequency of seizures. The mean dosage of zonisamide for favourable responders was 7.92 (SD 3.79) mg/kg, which was administered orally twice a day. Only one dog, which was one of the unfavourable responders in the whole study, experienced mild side effects. CONCLUSIONS: Among the dogs treated with oral zonisamide, 60% responded favourably. The effect of zonisamide as an anticonvulsant drug was demonstrated in this study. CLINICAL RELEVANCE: Based on these results, zonisamide monotherapy is effective in some dogs with idiopathic epilepsy.

Occurrence of antimicrobial resistance and virulence genes, and distribution of enterococcal clonal complex 17 from animals and human beings in Korea

Enterococci are major zoonotic bacteria that cause opportunistic infections in human beings and animals. Moreover, pathogenic strains can be disseminated between human beings and animals, particularly companion animals that come into frequent contact with people. Recently, Enterococcus faecium clonal complex 17 (CC17) has emerged as a pandemic clone. Most CC17 strains are ampicillin resistant and possess virulence genes such as esp and hyl. Despite the possible dissemination of CC17 between human beings and animals, prevalence data about CC17 in animals is limited. In the present study, the phenotypes and genotypes of antimicrobial resistance were compared, as well as virulence gene profiles from 184 enterococci strains isolated from chickens, pigs, companion animals, and human patients in Korea. Ampicillin-resistant E. faecium (AREF) strains were selected, and multilocus sequence typing was performed to investigate the dispersion of CC17 among animals and human beings. The companion animal and human isolates showed high resistance rates to ampicillin and ciprofloxacin, whereas food animal isolates showed high tetracycline and erythromycin resistance rates. Ampicillin-resistant E. faecium was only detected in human (21/21 E. faecium, 100%) and companion animal (3/5 E. faecium, 60%) isolates, and all human AREF strains and 1 canine AREF strain were confirmed as CC17. In conclusion, the occurrence of antimicrobial resistance and virulence genes, and the distribution of enterococcal CC17 in companion animal enterococcal strains were similar to those of human strains rather than to those of food animal strains.

Survey of Helicobacter infection in domestic and feral cats in Korea

Discovery of Helicobacter (H.) pylori has led to a fundamental change in our understanding of gastric diseases in humans. Previous studies have found various Helicobacter spp. in dogs and cats, and pets have been questioned as a zoonotic carrier. The present study surveyed the Helicobacter infections and investigated the presence of H. felis and H. pylori infections in domestic and feral cats in Korea. Sixty-four domestic cats and 101 feral cats were selected from an animal shelter. Saliva and feces were evaluated by Helicobacter genus-specific polymerase chain reaction (PCR). Genus-specific PCR positive samples were further evaluated for H. felis and H. pylori using specific primer pairs. Thirty-six of 64 (56.3%) samples from domestic cats and 92 of 101 (91.1%) samples from feral cats were PCR positive; the positive rate of feces samples was higher than that of saliva samples in both groups. H. felis and H. pylori species-specific PCR was uniformly negative. The prevalence of Helicobacter spp. in feral cats was approximately two-fold higher than that of domestic cats. The fecal-oral route may be more a common transmission route not only between cats but also in humans.

In Vitro Susceptibility of Malassezia pachydermatis Isolates from Canine Skin with Atopic Dermatitis to Ketoconazole and Itraconazole in East Asia

ABSTRACT Topical or oral azole antifungals are commonly used in canine atopic dermatitis (AD), as the lipophilic yeast Malassezia pachydermatis exacerbates canine AD. To examine whether canine AD lesions harbor azole-resistant M. pachydermatis isolates in East Asia, we investigated the in vitro susceptibility of M. pachydermatis isolates to ketoconazole (KTZ) and itraconazole (ITZ) obtained from AD lesions of canines in Japan, Korea and Taiwan. The minimum inhibitory concentrations (MICs) of KTZ and ITZ were measured by the E-test using Sabouraud dextrose agar with 0.5% Tween 40. The MICs of KTZ and ITZ for isolates from canines with AD were significantly higher than the MICs for isolates from healthy canines. Our findings suggested that the clinical isolates from canine AD skin lesions were less susceptible to azoles than those from normal canine skin in East Asia.

C-reactive protein as an indicator of inflammatory responses to experimentally induced cystitis in dogs

The aim of this study was to demonstrate and assess C-reactive protein (CRP) changes in dogs with induced bacterial cystitis with or without antibiotics. We also evaluated availability of CRP levels to serve as an indicator for monitoring or diagnosing bacterial cystitis. Serial CRP concentrations in dogs with induced bacterial cystitis were higher than those of controls (p < 0.001). CRP concentrations peaked on day 7 and gradually decreased thereafter. In the treatment group, CRP concentrations decreased after medication compared to the untreated group (p = 0.032). CRP levels had a linear correlation with urine white blood cell counts among all groups (r = 0.837, p < 0.001, n = 140). Compared to the negative urine culture group, dogs with positive urine culture results had higher CRP concentrations (median 43.8 mg/L vs. 5.9 mg/L; p < 0.001). Area under the receiver operating characteristic curve was 0.955; when cut-off value was 12.2 mg/L, CRP measurements were found to have a sensitivity of 92.3% and specificity of 86.4%. This result indicates that rapid increases of CRP occurred after inducing bacterial cystitis and CRP may be a useful indicator for monitoring or diagnosing canine bacterial cystitis together with sediment urinalysis and urine bacterial culture.

Clinical use of a ceramide-based moisturizer for treating dogs with atopic dermatitis.

In humans, skin barrier dysfunction is thought to be responsible for enhanced penetration of allergens. Similar to conditions seen in humans, canine atopic dermatitis (CAD) is characterized by derangement of corneocytes and disorganization of intercellular lipids in the stratum corenum (SC) with decreased ceramide levels. This study was designed to evaluate the effects of a moisturizer containing ceramide on dogs with CAD. Dogs (n = 20, 3~8 years old) with mild to moderate clinical signs were recruited and applied a moisturizer containing ceramide for 4 weeks. Transepidermal water loss (TEWL), skin hydration, pruritus index for canine atopic dermatitis (PICAD) scores, and canine atopic dermatitis extent and severity index (CADESI) scores of all dogs were evaluated. Skin samples from five dogs were also examined with transmission electron microscopy (TEM) using ruthenium tetroxide. TEWL, PICAD, and CADESI values decreased (p < 0.05) and skin hydration increased dramatically over time (p < 0.05). Electron micrographs showed that the skin barrier of all five dogs was partially restored (p < 0.05). In conclusion, these results demonstrated that moisturizer containing ceramide was effective for treating skin barrier dysfunction and CAD symptoms.

An autochthonous case of canine visceral leishmaniasis in Korea.

A 12-year-old spayed female mixed-bred dog presented with nasal bleeding of 2 days duration and a skin nodule in the left flank. No abnormalities were found in coagulation profiles and blood pressure. Cytological evaluation of the nodule revealed numerous characteristic round organisms having a nucleus and a bar within macrophages and in the background, consistent with leishmaniasis. In vitro culture was unsuccessful but PCR of the nodular aspirate identified the organisms as Leishmania infantum, and the final diagnosis was canine leishmaniasis. No history of travel to endemic countries was noted. Because the dog had received a blood transfusion 2 years before the illness, serological screening tests were performed in all donor dogs of the commercial blood bank using the commercial Leishmania ELISA test kit, and there were no positive results. Additional 113 dogs with hyperglobulinemia from Seoul were also screened with the same kits but no positive results were obtained. To the best of the authors knowledge this is the first autochthonous case of canine leishmaniasis in Korea.

Molecular analysis of Malassezia pachydermatis isolated from canine skin and ear in Korea

We investigated Malassezia species and genotypes colonizing dogs, comparing those recovered from the ear canal with those from other anatomical body sites, as well as from diseased and healthy skin. The Malassezia isolates were obtained from four types of skin samples, i.e., diseased ear, diseased skin, healthy ear, and healthy skin. Sequences of the 26S ribosomal DNA region, the intergenic spacer 1 (IGS-1) and the internal transcribed spacer 1 (ITS-1) DNA region were analyzed. These confirmed the presence of Malassezia pachydermatis, which could be separated into three main sequence genotype groups (A, B, C). Genotype A was the most common, only two genotype B isolates were recovered from diseased skin lesion and genotype C was more likely to be isolated from ear samples than from other healthy or diseased-skin sites. The present findings provide the basis for further studies of genotypic diversity in M. pachydermatis, as well as their pathogenic potential.

Identification of VIM-2 metallo-β-lactamase-producing Pseudomonas aeruginosa isolated from dogs with pyoderma and otitis in Korea

BACKGROUND Pseudomonas aeruginosa is a challenging pathogen cultured from cases of acute and chronic canine otitis and sometimes in cases of deep pyoderma. The spread of antimicrobial resistance, especially carbapenem resistance, is a serious therapeutic challenge worldwide. HYPOTHESIS/OBJECTIVES To investigate the identification and characterization of resistant P. aeruginosa clinical canine isolates. MATERIALS Clinical isolates (n = 80) were collected from dogs with pyoderma (n = 18) and otitis (n = 62) in Korea. METHODS Antimicrobial susceptibility was determined using agar dilution and using Clinical and Laboratory Standards Institute guidelines for recording susceptibility for human Pseudomonas isolates; genetic relatedness of isolates was investigated by multilocus sequence typing (MLST) and SpeI macrorestriction analysis. The class 1 integrons were amplified and sequenced using primer walking. RESULTS Most isolates were susceptible to colistin (97.5%), polymyxin B (96.3%), ciprofloxacin (81.3%) and meropenem (80.0%); whereas resistance to aztreonam (80%), piperacillin (52.5%), piperacillin/tazobactam (41.3%) and cefepime (37.5%) was high; 12 carbapenem-nonsusceptible isolates (15%) were detected. MLST revealed 45 different sequence types (STs) and macrorestriction analysis detected 55 distinct pulsotypes (PTs), which were divided into 25 clonal groups. Among carbapenem-nonsusceptible isolates, 10 (83.3%) were VIM-2-producing strains. Nine VIM-2-producing isolates were identified as ST1047 and harboured the same 2.8 kb class 1 integron. One remaining isolate was ST1203 with 2.1 kb class 1 integron. CONCLUSIONS AND CLINICAL IMPORTANCE This study demonstrated the diversity of the phenotype and genotype of clinical P. aeruginosa isolates from dogs with pyoderma and otitis. The identification of VIM-2-producing P. aeruginosa in dogs is alarming and warrants further surveillance.