Molecular prophage typing of Staphylococcus aureus isolates from bovine mastitis

Staphylococcus aureus is one of the major pathogens causing bovine mastitis and foodborne diseases associated with dairy products. To determine the genetic relationships between human and bovine or bovine isolates of S. aureus, various molecular methods have been used. Previously we developed an rpoB sequence typing (RSTing) method for molecular differentiation of S. aureus isolates and identification of RpoB-related antibiotic resistance. In this study, we performed spa typing and RSTing with 84 isolates from mastitic cows (22 farms, 72 cows, and 84 udders) and developed a molecular prophage typing (mPPTing) method for molecular epidemiological analysis of bovine mastitis. To compare the results, human isolates from patients (n = 14) and GenBank (n = 166) were used for real and in silico RSTing and mPPTing, respectively. Based on the results, RST10-2 and RST4-1 were the most common rpoB sequence types (RSTs) in cows and humans, respectively, and most isolates from cows and humans clearly differed. Antibiotic resistance-related RSTs were not detected in the cow isolates. A single dominant prophage type and gradual evolution through prophage acquisition were apparent in most of the tested farms. Thus, RSTing and mPPTing are informative, simple, and economic methods for molecular epidemiological analysis of S. aureus infections.

Molecular identification of coagulase-negative staphylococci by rpoB sequence typing / 대한수의학회지

Bovine mastitis (BM) has resulted in enormous economic loss in the dairy industry and coagulase-negative staphylococci (CNS) have caused subclinical BM. Although VITEK 2 GP ID card (VITEK 2) has been used for CNS identification, the probability of identification varies. The rpoB sequence typing (RSTing) method has been used for molecular diagnosis and epidemiology of bacterial infections. In this study, we undertook RSTing of CNS and compared the results with those of VITEK2 and 16S rRNA gene sequencing. As compared VITEK2, the molecular-based methods were more reliable for species identification; moreover, RSTing provided more molecular epidemiological information than that from 16S rRNA gene sequencing.

Molecular identification of coagulase-negative staphylococci by rpoB sequence typing

Bovine mastitis (BM) has resulted in enormous economic loss in the dairy industry and coagulase-negative staphylococci (CNS) have caused subclinical BM. Although VITEK 2 GP ID card (VITEK 2) has been used for CNS identification, the probability of identification varies. The rpoB sequence typing (RSTing) method has been used for molecular diagnosis and epidemiology of bacterial infections. In this study, we undertook RSTing of CNS and compared the results with those of VITEK2 and 16S rRNA gene sequencing. As compared VITEK2, the molecular-based methods were more reliable for species identification; moreover, RSTing provided more molecular epidemiological information than that from 16S rRNA gene sequencing.

Identification of microbiome with 16S rRNA gene pyrosequencing and antimicrobial effect of egg white in bovine mastitis

Bovine mastitis is an important microbial disease in the dairy industry. We investigated the frequencies of bacterial pathogens in 62 farms and pathogen antibiotic resistance from mastitis samples (n = 748). We tested the antimicrobial activity of chicken and duck egg white and lysozyme purified from chicken egg white. Moreover, we compared the microbiomes of normal and mastitic raw milk obtained by 16S rRNA gene pyrosequencing and culture methods. The results showed that the frequencies of Gram-positive pathogens (Enterococcus faecalis 37% and Staphylococcus aureus 36%) were higher than that of a Gram-negative pathogen (Escherichia coli 15%). Resistance frequencies to ampicillin and norfloxacin were lowest in Staphylococcus aureus (21%), Enterococcus faecalis (23%), and Escherichia coli (33%), and the antimicrobial activity of chicken egg white was higher than those of lysozyme and duck egg white. Pyrosequencing results revealed clear differences between the microbiomes of mastitic and normal raw milk samples and revealed a slightly similar, but clearly different, composition of pathogens compared to that from the culture method. Thus, pyrosequencing may be useful for elucidating changes in microbiomes during mastitis progression and treatment. A chicken egg white and antibiotic combination may help with mastitis treatment; however, further studies are needed.

rpoB gene sequencing for phylogenetic analysis of avian pathogenic Escherichia coli / 대한수의학회지

The present study was conducted to determine the full rpoB and eight house-keeping gene sequences of 78 and 35, respectively, avian pathogenic E. coli (APEC) strains. Phylogenetic comparison with 66 E. coli and Shigella strains from GenBank and EMBL was also conducted. Based on the full rpoB sequence, 50 different rpoB sequence types (RSTs) were identified. RST 1 was assigned to a major RST that included 34.7% (50/144) of the analyzed strains. RST 2 to RST 50 were then assigned to other strains with higher nucleotide sequence similarity to RST 1 in order. RST 1, 11, and 23 were mixed with APEC along with human commensal and pathogenic strains while RST 2, 6, 9, 13-15, 22, 24, 25, 33, 34, 36, and 41 were unique to APEC strains. Only five APEC strains grouped into RST 32 and 47, which contained human pathogenic E. coli (HPEC). Thus, most of the APEC strains had genetic backgrounds different from HPEC strains. However, the minor APEC strains similar to HPEC should be considered potential zoonotic risks. The resolution power of multi-locus sequence typing (MLST) was better than RST testing. Nevertheless, phylogenetic analysis of rpoB was simpler and more economic than MLST.

Clinico-pathological Features of Chlamydophila psittaci Infection in Parrots and Genetic Characterization of the Isolates / 대한수의학회지

Avian chlamydiosis is caused by Chlamydophila psittaci and considered as one of an important zoonotic disease throughout the world. Among more than 400 avian species including poultry and pet birds susceptible to the disease, psittacine birds were known to be mostly susceptible hosts. In Korea, no outbreak of the disease and genetic analysis of the agent in poultry and pet birds have been reported. With histopathological findings and genetic identification of a causative agent, avian chlamydiosis was identified in parrots submitted from the same pet bird farm in 2006 and 2009 for the diagnosis. Based on genetic sequences and phylogenetic analysis of ompA gene, the two isolates of Chlamydophila psittaci showed 100% of genetic similarity and belonged to genotype A, suggesting that the same agent might be continuously circulated in the farm. This result indicates that serological survey of the disease in pet bird farms and impact of the disease on significance in public health may be further studied.

Three Cases of Lymphoepithelial Carcinoma / 대한이비인후과학회지

Lymphoepithelial carcinoma was first reported in 1962. Since then, about 130 cases have been reported in the English-language literature. Lymphoepithelial carcinoma is a rare tumor of the major salivary gland. Most reported cases have occurred in Asians and Eskimos. We report two cases of lymphoepithelial carcinoma of the major salivary glands and one case of lymphoepithelial carcinoma of unknown origin. They received operation and postoperative radiotherapy. At follow-up, they remained free of disease.

Clinical Findings of Recurrent Respiratory Papillomatosis and Preliminary Results of the Adjuvant Therapy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Recurrent respiratory papillomatosis (RRP) is difficult to treat because of its tendency to recur and spread throughout the respiratory tract. RRP is usually divided into two groups by age of onset. We aimed to investigate the different clinical courses between the childhood-onset and the adult-onset RRP and review the effects of the treatments. MATERIAL AND METHOD: We retrospectively reviewed 44 patients with RRP who had been treated in our hospital over the last 13 years. We compared the clinical courses and intersurgical intervals of childhood-onset RRP with those of adult-type and evaluated the effect of the alpha-interferon (local injection) by comparing preadjuvant average surgical interval with postadjuvant surgical interval with a review of the literature. RESULTS: Childhood-onset RRP was most often diagnosed between 1 and 4 years of age. It was more widespread and it recurred more frequently than adult-onset RRP, often involving the trachea and necessitating the tracheostomy. Therefore, more frequent surgical interventions were needed in childhood-onset RRP (2.81/year) than in the adult-type (1.14/year). Adjuvant therapy (local injection of alpha-interferon) was applied to 10 patients. Seventy-five percent of the 8 patients (2 were excluded due to short duration of F/U period) showed complete response (CR) or partial resopnse (PR) and only two patients did not respond to alpha-interferon at all. CONCLUSION: Childhood-onset RRP is more aggressive and widespread than its adult counterpart and intralesional injection of alpha-interferon seems to have a potential of a safe and effective adjuvant therapy for RRP.