Antimicrobial Susceptibility and Genetic Analysis of Campylobacter jejuni Isolated from Diarrhea Patients in Busan / 대한임상미생물학회지

BACKGROUND: Campylobacter jejuni is an important food-borne pathogen that causes human gastroenteritis. This study was conducted to investigate the incidence of isolation, antimicrobial susceptibility pattern, and C. jejuni genotype from diarrhea patients in Busan, Korea. METHODS: A total of 97 C. jejuni were isolated from diarrhea patients during five food-borne outbreaks from 2014 to September 2017. Antimicrobial susceptibility tests were carried out by the broth microdilution method for ciprofloxacin (CIP), nalidixic acid (NAL), tetracycline (TET), chloramphenicol, azithromycin (AZI), erythromycin (ERY), streptomycin (STR), gentamicin, and telithromycin. To investigate C. jejuni genotypes, pulsed-field gel electrophoresis (PFGE) profile analysis was performed. RESULTS: The isolation rate of C. jejuni was 2.0% for the last 4 years and increased annually. Antimicrobial resistance rates of C. jejuni were shown to be in the order of NAL (90.9%), CIP (89.4%), TET (13.6%), AZI (3.0%), ERY (3.0%), and STR (1.5%). The proportion of multidrug-resistance was 18.2%, and they commonly contained quinolones (CIP-NAL). Analysis of PFGE patterns of SmaI-restricted DNA of C. jejuni isolates showed 17 clusters; cluster 11 was the major genotype pattern. CONCLUSION: This study will provide useful data for the proper use of antimicrobials and the management of resistant C. jejuni. Also it will help to provide data for the epidemiological investigation of foodborne diseases caused by C. jejuni, which is expected to increase in the future.

Study on Causes of Respiratory Disease to the Middle East Respiratory Syndrome-negative Subjects

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe cases of human respiratory disease. The current outbreak of infection with this virus in South Korea, which began on May 20, 2015, has infected 186 patients and caused 36 deaths within 2 months. In this study, to investigate the viral pathogen causing acute respiratory infections, multiplex/RT-PCR was performed on were obtained from nucleic acid of the Middle East Respiratory Syndrome-negative subjects. Viruses and atypical bacteria were detected in 39 of 337 (11.6%). Frequent viruses were human rhinovirus (n=11, 3.3%), human metapneumovirus (n=9, 2.7%), parainfluenza (n=9, 2.7%) and adenovirus (n=4, 1.2%). Mycoplasma pneumonia (M. pneumonia) was detected in 1.8 % (n=6). Out of 9 human metapneumovirus (hMPV) positive samples, 6 samples were successfully sequenced using F gene. And M. pneumoniae was sequencing of a repetitive region of the P1 gene. Phylogenetic analysis revealed that hMPV clustered into A2b lineage (n=4), B2 lineage (n=2) and M. pneumoniae clustered into two genotypes: Type 1 (n=4), Type 2a (n=2).

Study on Causes of Respiratory Disease to the Middle East Respiratory Syndrome-negative Subjects

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe cases of human respiratory disease. The current outbreak of infection with this virus in South Korea, which began on May 20, 2015, has infected 186 patients and caused 36 deaths within 2 months. In this study, to investigate the viral pathogen causing acute respiratory infections, multiplex/RT-PCR was performed on were obtained from nucleic acid of the Middle East Respiratory Syndrome-negative subjects. Viruses and atypical bacteria were detected in 39 of 337 (11.6%). Frequent viruses were human rhinovirus (n=11, 3.3%), human metapneumovirus (n=9, 2.7%), parainfluenza (n=9, 2.7%) and adenovirus (n=4, 1.2%). Mycoplasma pneumonia (M. pneumonia) was detected in 1.8 % (n=6). Out of 9 human metapneumovirus (hMPV) positive samples, 6 samples were successfully sequenced using F gene. And M. pneumoniae was sequencing of a repetitive region of the P1 gene. Phylogenetic analysis revealed that hMPV clustered into A2b lineage (n=4), B2 lineage (n=2) and M. pneumoniae clustered into two genotypes: Type 1 (n=4), Type 2a (n=2).

Positive Rate of Antibody Against Dengue Virus for Korean Who Traveled to Dengue Epidemic Area

BACKGROUND: Recently, dengue fever has increased throughout tropical regions and emerged as the most important vector borne viral disease in human. 4 serotypes of viruses are circulating concurrently in these regions and thus it may be anticipated to increase risk of dengue hemorrhagic fever. Even though dengue fever is still not endemic in Korea, it is necessary to test antibodies against dengue viruses because the number of Koreans who have visited these regions is continuously increasing. MATERIALS AND METHODS: Serum specimens from persons with suspected dengue fever had been collected. Commercial kit, immunochromatographic test (ICA), and the IgM capture enzyme-linked immunosorbent assay (MAC-ELISA) were employed for dengue fever detection in these studies. For confirmation randomized 25 specimens among total of 99 specimens were selected and compared with those results from commercial kit and IFA. RESULTS: 33 (33.3%) among 99 specimens showed positive antibody against dengue virus by commercial kit. Positive rate of traveller who have visited Indonesia, Philippines, Malaysia, Thiland was 54.5%. To compare the efficiency of test methods, 25 randomly selected specimens were tested by the MAC-ELISA and IFA simultaneously. 9 specimens showed postive results with the MAC-ELISA method whereas 13 speciments were positive with the IFA methods. CONCLUSION: Confirming the diagnosis of dengue fever with antibody against dengue virus was attempted for the first time in Korea. The results from our study indicate that establishing a national surveillance and/or laboratory diagnostic system in Korea are necessary. In addtion, antibody test strategies for national surveillance system should be carefully considered.

Positive Rate of Antibody Against Dengue Virus for Korean Who Traveled to Dengue Epidemic Area

BACKGROUND: Recently, dengue fever has increased throughout tropical regions and emerged as the most important vector borne viral disease in human. 4 serotypes of viruses are circulating concurrently in these regions and thus it may be anticipated to increase risk of dengue hemorrhagic fever. Even though dengue fever is still not endemic in Korea, it is necessary to test antibodies against dengue viruses because the number of Koreans who have visited these regions is continuously increasing. MATERIALS AND METHODS: Serum specimens from persons with suspected dengue fever had been collected. Commercial kit, immunochromatographic test (ICA), and the IgM capture enzyme-linked immunosorbent assay (MAC-ELISA) were employed for dengue fever detection in these studies. For confirmation randomized 25 specimens among total of 99 specimens were selected and compared with those results from commercial kit and IFA. RESULTS: 33 (33.3%) among 99 specimens showed positive antibody against dengue virus by commercial kit. Positive rate of traveller who have visited Indonesia, Philippines, Malaysia, Thiland was 54.5%. To compare the efficiency of test methods, 25 randomly selected specimens were tested by the MAC-ELISA and IFA simultaneously. 9 specimens showed postive results with the MAC-ELISA method whereas 13 speciments were positive with the IFA methods. CONCLUSION: Confirming the diagnosis of dengue fever with antibody against dengue virus was attempted for the first time in Korea. The results from our study indicate that establishing a national surveillance and/or laboratory diagnostic system in Korea are necessary. In addtion, antibody test strategies for national surveillance system should be carefully considered.