• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.281-286
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• 2022

This study was conducted to investigate the detection rate and serotypes of Salmonella spp. in conventional and welfare poultry farms. Ten welfare (five layer and five broiler) and 15 conventional farms (five layer and ten broiler farms) were visited to collect environmental samples for identification and serotyping of Salmonella spp. The detection rate of Salmonella spp. was higher in the welfare farms than in conventional farms in both layer and broiler farms. In layer farms, Salmonella spp. was detected in 0.76% (1 out of 130) of samples from one of five welfare layer farms, but was not detected in the five in conventional layer farms. No significan ifference (P>0.05) was observed between the welfare and conventional layer farms. In broiler farms, Salmonella spp. was detected in 10.5% (21 out of 200) of samples from four of five welfare broiler farms and 3.5% (7 out of 200) of samples from five of ten conventional broiler farms, and a significant difference (p <0.05) was observed between the welfare and conventional broiler farms. Among 29 Salmonella spp. isolates, five isolates were serotyped to Salmonella enterica subsp. Enteritidis (n=2), Salmonella enterica subsp. Grampian (n=1), Salmonella enterica subsp. Virchow (n=1), and Salmonella enterica subsp. Senftenberg (n=1). These results suggest that microbial risks could be higher in welfare farms than in conventional farms due to easy access to open-air areas, environmental enrichment, and reduced use of antibiotics. Therefore, continuous monitoring and surveillance for Salmonella spp. is necessary to improve the microbiological safety of poultry meat.

• Pediatric Infection and Vaccine
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• v.15 no.1
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• pp.45-51
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• 2008

Purpose : Better understanding of the epidemiology of Streptococcus pneumoniae affects preventive and therapeutic strategies for children with otitis media. This study was undertaken to examine the prevalence of pneumococcal serotypes causing otitis media in children. Methods : Pneumococcal isolates obtained from the ear discharge of children with otitis media between January 2001 and December 2006 were characterized by serotyping and antibiotic susceptibility testing. Results : There were 54 pneumococcal isolates from 54 children with otitis media. The median age of patients was 13 months, and the proportion of children <5 years old was 81%. The predominant serotypes, in order of decreasing frequency, were 19A (44%), 19F(28%), 6B (7%), 6A (4%), 9V (4%), and 1 (4%); 23 isolates (43%) belonged to types included in the heptavalent pneumococcal conjugate vaccine (PCV7). The proportion of serotype 19A and 19F accounted for 72% of overall pneumococcal isolates, which accounted for 84% of pneumococcal isolates from otorrhea of children <5 years old (vs 20% in children ${\geq}5$ years old, P<0.001). All serotypes isolated from 3 vaccinees of PCV7 were 19A. There was no significant diminution in otitis media caused by pneumococcal vaccine serotypes after the introduction of PCV7. The frequency of nonsusceptibility to penicillin, erythromycin, and trimethoprim-sulfamethoxazole was higher in serotype 19A than in other non-vaccine serotypes, respectively. The frequency of multiple drug resistance was 96% in serotype 19A, compared with 29% in other non-vaccine serotypes (P=0.001). Conclusion : 19A was the most common pneumococcal serotype causing otitis media and represented a large proportion of strains with multiple drug resistance in children younger than 5 years of age.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.403-410
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• 2013

This study was performed to evaluate the microbiological contamination level of raw beef from retail markets in Seoul, Korea. The sampling and laboratory test were performed according to the procedure of "Standard for processing and ingredients specification of livestock product" and "Korean food code". Enterotoxin of Staphylococcus aureus isolates were detected using VIDAS$^{(R)}$ and PCR-based methods. Listeria monocytogenes serotyping and genotyping were carried out using Listeria antisera and L. monocytogenes Fingerprinting kit, respectively. A total of 48 samples were collected from 16 retail markets (butcher's shop: 5, department store: 6, supermarket: 5) in 2011. The level of total bacteria counts in the butcher's shop, department store and supermarket were $4.4{\times}10^3$ CFU/g, $3.9{\times}10^5$ CFU/g and $1.0{\times}10^4$ CFU/g, respectively. The concentrations of Escherichia coli of these three retail markets were $6.4{\times}10$ CFU/g, 7.6 CFU/g and $2.0{\times}10$ CFU/g, respectively. Salmonella species was not detected on all samples. However, S. aureus was isolated in the 3 samples (6.25%) from each type of three retail markets. L. monocytogenes was isolated in the 4 samples (8.3%) from department stores. The level of contamination of these foodborne bacteria was less than 100 CFU/g. The enterotoxin-encoding genes of S. aureus isolates were sea, seh, sei and sep gene. The gene similarity of L. monocytogenes isolated from two retail markets by Rep-PCR showed 57.8-98.1% and 68.1-98.1%, respectively. These results suggest that the HACCP guideline for environmental control in slaughterhouse and retail markets should be provided to prevent cross contamination and manage foodborne pathogens such as L. monocytogenes and S. aureus.

• Pediatric Infection and Vaccine
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• v.13 no.2
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• pp.106-114
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• 2006

Purpose : Studying the serotypes and emm genotype of group A streptococci(GAS) hold a key role in the investigation of epidemiology, pathogenesis, and resistance to antibiotics. We planed to find out the possible differences in serotypes and genotypes between the invasive and the non-invasive GAS infection. Methods : We obtained 39 isolates from the patients hospitalized in 2004 with the diagnosis of invasive GAS infectious diseases in the Severance Hospital, Yonsei University. We sent the isolates to the WHO Collaboratory Center in University of Minnesota and analyzed T serotypes and emm genotypes. These results were compared with non-invasive GAS infections in our hospital. Results : Compared this data with the results of 2003 to 2004, T2/28, T3, T5/27/44, T9 and NT were more prevalent. The NT showed statistically significant difference(P=0.019). The emm 3, emm 9, emm 18, emm 44 and emm provision type STG485 were more frequent genotypes compared with the study in 2003~2004, relatively. The emm provision type STG485 had statistically significant difference(P=0.000). The incidence of T12 plus T4, known as erythromycin(EM) resistant serotypes, was as low as 17.9% in this study, compared with those of non-invasive strains. Conclusion : The incidence of EM-resistant strains is supposed not to be higher in invasive GAS infection. We could find out possible higher incidence of rheumatogenic strains in the invasive GAS infections. It seems to be important to have an effort on studying of serotyping and genotyping for the monitoring of strains and to know the epidemiologic characteristics.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.79-84
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• 2002

Purpose : About 41% of obtained group A streptococci in the 1998 was reported as erythromycin-resistant streptococci in Seoul, Korea. The most common T serotype was T12, followed by T4 and T28. We'd like to monitor the serological changes and antibiotic sensitivity test of Streptococcus pyogenes obtained from the patients with pharyngotonsillitis and invasive diseases from 1999 through 2001. Also, it could be proposed to choose the proper antibiotic selection in the area where the rate of erythromycin-resistant streptococci is high. Methods : From Jan. 1999 to Oct. 2001, 208 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis, scarlet fever, and invasive infections in Seoul and Southern part of peninsula. All isolates were serotyped by T-agglutination, minimum inhibitory concentrations(MICs) which were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). Results : The most common T serotype was T12(29.8%), followed by T1(23.1%), T4 (14.9%). T1 was prominent serotype compared with previous year. T serotyping, among 25 isolates obtained from the patients with scarlet fever in Southern part of peninsula mostly, was T12, T1, and T4 in order of frequency. All the isolates tested were susceptible to penicillin, cefprozil, vancomycin, ceftriaxone, and chloramphenicol. However, 23 isolates(14.2%) was resistant to erythromycin and 18 isolates(11.1%) was resistant to clarithromycin. Serotype T12 was found to be the most resistant serotype to erythromycin and/or clarithromycin. Conclusion : High rate of erythromycin-resistant streptococci which surveyed in 1998 were reduced to 14.2% in this study. We should have to further evaluate the reason of decreased resistant strains and consider the resistant strains of streptococci in choosing the antibiotics. There was no serological characteristics according to the types of disease entities. Between the serologic distributions in Seoul and the Southern part of peninsula area are same, we could presume that the serological typing of strains obtained over the country may be not different.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.79-86
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• 2017

Purpose: This study was aimed at analyzing the serotypes of group B streptococcus (GBS) isolated from Korean infants with invasive disease and evaluating their association with disease manifestation. Methods: Data were retrospectively collected from invasive GBS infections at Gachon University Gil Medical Center from January 2006 to June 2012 and at Samsung Medical Center from April 2010 to November 2012. Serotypes were determined by slide agglutination test. Results: A total of 37 cases were identified, which included 22 full-term infants and 15 preterm infants. Fifteen cases (40.5%) were early-onset, 19 (51.4%) was late-onset, and three (8.1%) was very late-onset. Early-onset diseases among preterm infants were higher than those among full-term infants (60.0% [9/15] vs. 27.3% [6/22], P=0.17). The most common manifestation was bacteremia (70.3%), followed by meningitis and septic arthritis. Among 24 isolates retrievable for serotyping, serotype III (41.7%) was most common, followed by V (16.7%), Ia, Ib, and II (12.5%, respectively), and non-typeable (4.2%). Serotype III was more common in isolates from full-term infants (10/22) than from preterm infants (0/15), whereas serotype V was more common in isolates from preterm infants (4/15) than from full-term infants (0/22) (P=0.002). No penicillin-resistant strain was detected, and resistance to erythromycin and clindamycin were both 64.9%. Conclusions: GBS is an important pathogen in both preterm and full-term infants, and serotype distribution of GBS causing invasive diseases can differ between preterm and full-term infants. It is necessary to monitor the nationwide epidemiology of GBS diseases, including in preterm infants, in order to prepare preventive measures without underestimating early-onset diseases.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.9-15
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• 2024

This study was performed to survey the distribution of Listeria spp. in fresh agricultural products in the Busan area, the Republic of Korea, from January to November 2022. We investigated the pathogenicity and epidemiological relationships by tracing isolated strains using polymerase chain reaction and pulsed-field gel electro-phoresis (PFGE) methods. Forty cases of Listeria spp. were detected in the 210 samples of fresh agricultural products analyzed. Four species, Listeria rocourtiae, L. innocua, L. grayi, and L. monocytogenes were detected only in green vegetables (lettuce, perilla leaps) and the others (L. innocua, L. monocytogenes, and L. grayi) were detected in enoki and oyster mushrooms. L. innocua was detected in 22 samples and L. grayi in six samples. L. monocytogenes, which causes foodborne diseases, was only detected in enoki mushrooms and the strains that were isolated had genes responsible for the pathogenicity of listeriosis (iap, prfA, inlA, inlC, inlJ, and hly). To investigate the genetic similarity and contamination route of L. monocytogenes, serotyping and PFGE were conducted for 12 strains isolated from fresh agricultural (10 strains) and poultry (2 strains) products distributed at a market in the Busan area. Two serotypes (1/2a, 1/2b) were detected in strains isolated from the agricultural and poultry products, but serotype 1/2b was only detected in strains isolated from agricultural products. PFGE analysis showed index of similarity values of 45.7 to 100% and the same patterns were represented in isolates from some enoki mushrooms. These isolates had the same serotypes and showed significant epidemiological relationships.