Cluster of Serogroup W-135 Meningococcal Disease in 3 Military Recruits

We describe a group of 3 cases of invasive meningococcal disease that occurred in a military training camp in April 2011. All three patients were hospitalized. Ultimately, two patients recovered and one died. One patient had meningitis, one patient had septicemia and meningitis, and the other had no definite septicemia or meningitis. Neisseria meningitidis serogroup W-135 was detected in the serum and cerebrospinal fluid (CSF) of all patients by real-time polymerase chain reaction. In the one case of mortality, two strains were isolated from the patient's blood and CSF. Using multilocus sequence typing analysis, these strains were identified as a novel sequence type, ST-8912. Special attention is required for the meningococcal disease in military camp because the military personnels are in high risk of contact transmission.

Alpha1-Adrenoceptor Antagonists Improve Memory by Activating N-methyl-D-Aspartate-Induced Ion Currents in the Rat Hippocampus / 대한배뇨장애요실금학회지

PURPOSE: Alpha1 (alpha1)-adrenoceptor antagonists are widely used to treat lower urinary tract symptoms. These drugs not only act on peripheral tissues, but also cross the blood-brain barrier and affect the central nervous system. Therefore, alpha1-adrenoceptor antagonists may enhance brain functions. In the present study, we investigated the effects of tamsulosin, an alpha1-adrenoceptor antagonist, on short-term memory, as well as spatial learning and memory, in rats. METHODS: The step-down avoidance test was used to evaluate short-term memory, and an eight-arm radial maze test was used to evaluate spatial learning and memory. TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling) staining was performed in order to evaluate the effect of tamsulosin on apoptosis in the hippocampal dentate gyrus. Patch clamp recordings were used to evaluate the effect of tamsulosin on ionotropic glutamate receptors, such as N-methyl-D-aspartate (NMDA), amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and kainate receptors, in hippocampal CA1 neurons. RESULTS: Tamsulosin treatment improved short-term memory, as well as spatial learning and memory, without altering apoptosis. The amplitudes of NMDA-induced ion currents were dose-dependently increased by tamsulosin. However, the amplitudes of AMPA- and kainate-induced ion currents were not affected by tamsulosin. CONCLUSIONS: Tamsulosin enhanced memory function by activating NMDA receptor-mediated ion currents in the hippocampus without initiating apoptosis. The present study suggests the possibility of using tamsulosin to enhance memory under normal conditions, in addition to its use in treating overactive bladder.

The Prevalence and Characteristics of Bacteria Causing Acute Diarrhea in Korea, 2012 / 대한임상미생물학회지

BACKGROUND: Through change in the climate and living environment, bacterial pathogens that cause diarrhea also change. This study sought to determine the characteristics of pathogens according to species, isolated region, and patient age/sex using National Surveillance Data for diarrhea, and to provide basic data for the prevention of diarrheal disease. METHODS: From January to December 2012, stool specimens were collected from 21,180 diarrheal patients in Korea to identify the pathogenic bacteria involved. Pathogenic bacteria were analyzed according to isolated region and patient age/sex. Identification and analysis of the pathogens were conducted based on the Guidelines of the National Institute of Health Diagnostic Laboratory: Disease-specific protocol (2005). RESULTS: Among the 21,180 stool specimens, pathogenic bacteria known to cause diarrhea were isolated from 2,444 stool specimens (11.5%). The isolation rate was highest in the summer (from June to September) for most pathogenic bacteria, except Escherichia coli, Staphylococcus aureus, and Clostridium perfringens. The isolation rate of pathogenic bacteria based on patient age was highest in children under the age of 10. CONCLUSION: Hygiene education should be addressed in diarrheal disease-susceptible groups, such as children under 10, people in their 50s, and those greater than 70 years old, and ongoing monitoring for pathogens is needed. In addition, an efficient information system and surveillance program should be continued for infection prevention.

Carriage Rates and Serogroups of Neisseria meningitidis among Freshmen in a University Dormitory in Korea

PURPOSE: Neisseria meningitidis is a leading cause of bacterial meningitis in young adults. University students, especially those living in dormitories, have been known to be at increased risk of meningococcal disease. We performed a longitudinal study to determine the carriage rates of N. meningitidis and the changes thereof. MATERIALS AND METHODS: We recruited Inha University freshmen who were, at that time, admitted to a student dormitory. A pharyngeal swab was taken from all participant who were also asked to complete a questionnaire. This was repeated four weeks later. RESULTS: A total of 136 students were enrolled at the first culture. After four weeks, 128 students were enrolled, including 106 re-participants. The overall carriage rates changed from 11.8% to 14.1%. In analysis of the 106 re-participants, "visiting to pubs" was associated with carriage of N. meningitis for both the first (p=0.047) and second cultures (p=0.026). Serogroup C was found to be the most frequent serogroup (5 isolates), while 3 isolates were found from serogroup B. The most prevalent PorA types were P1.22,14-6 (4 isolates) and P1.19,15 (3 isolates). The DNA sequences of PorA VR2 were changed in 2 students during prolonged carriage. CONCLUSION: The meningococcal carriage rate among first year university students who resided in a dormitory did not significantly increase over 4-week interval between cultures, which is markedly different from those reported in Western studies. Close social contact appeared to be related with carriage. Our data also revealed diversity in PorA types, suggesting the possibility of rapid mutation of the PorA gene during the 4-week interval.

Discriminative PCR of Bordetella pertussis from closely related Bordetella species using 16S rDNA Gene / 감염과화학요법

BACKGROUND: Polymerase-chain reaction (PCR) detection is useful to diagnosis of pertussis at initial stage because the growth rate of Bordetella pertussis (B. pertussis) is relatively slow. Currently, the primer set for the insertion sequence IS481 (BP primer) is used widely for PCR detection of B. pertussis. However, the cross-reactivity of BP primer set with Bordetella holmesii (B. holmesii) was reported recently. Therefore, discrimination of B. pertussis and B. holmesii is needed in PCR step. For this reason, we developed new primer sets based on 16S rDNA sequence for diagnostic use and estimated the efficiency of these new primer sets. MATERIALS AND METHODS: The specific PCR primers were designed from the aligned sequence matrix of 16S rDNA genes of various Bordetella species. The specificity of designed primers were estimated using clinically important 4 Bordetella species, B. pertussis, B. holmesii, Bordetella parapertussis (B. parapertussis) and Bordetella bronchiseptica (B. bronchiseptica). The sensitivity to B. pertussis of designed primers was also estimated and compared with BP primer set. RESULTS: As the results, the developed new primer set successfully distinguished B. pertussis and other Bordetella species containing B. holmesii. In the sensitivity assay, the detectable limits of 16S-F2/16S-R1 primer set for B. pertussis were revealed as 5 pg of genomic DNA and 105 cells/mL of cell suspension. In addition to these, identical results between BP with primer and new primer were obtained in clinical samples. CONCLUSION: In this study, the specific primer set for B. pertussis was developed based on 16S rDNA sequence and this primer set did not show cross-reactivity to B. holmesii. In addition to these, the applicability of this primer set to the clinical specimens was also confirmed.

Discriminative PCR of Bordetella pertussis from closely related Bordetella species using 16S rDNA Gene / 감염과화학요법

BACKGROUND: Polymerase-chain reaction (PCR) detection is useful to diagnosis of pertussis at initial stage because the growth rate of Bordetella pertussis (B. pertussis) is relatively slow. Currently, the primer set for the insertion sequence IS481 (BP primer) is used widely for PCR detection of B. pertussis. However, the cross-reactivity of BP primer set with Bordetella holmesii (B. holmesii) was reported recently. Therefore, discrimination of B. pertussis and B. holmesii is needed in PCR step. For this reason, we developed new primer sets based on 16S rDNA sequence for diagnostic use and estimated the efficiency of these new primer sets. MATERIALS AND METHODS: The specific PCR primers were designed from the aligned sequence matrix of 16S rDNA genes of various Bordetella species. The specificity of designed primers were estimated using clinically important 4 Bordetella species, B. pertussis, B. holmesii, Bordetella parapertussis (B. parapertussis) and Bordetella bronchiseptica (B. bronchiseptica). The sensitivity to B. pertussis of designed primers was also estimated and compared with BP primer set. RESULTS: As the results, the developed new primer set successfully distinguished B. pertussis and other Bordetella species containing B. holmesii. In the sensitivity assay, the detectable limits of 16S-F2/16S-R1 primer set for B. pertussis were revealed as 5 pg of genomic DNA and 105 cells/mL of cell suspension. In addition to these, identical results between BP with primer and new primer were obtained in clinical samples. CONCLUSION: In this study, the specific primer set for B. pertussis was developed based on 16S rDNA sequence and this primer set did not show cross-reactivity to B. holmesii. In addition to these, the applicability of this primer set to the clinical specimens was also confirmed.

Prevalence of Mycoplasma pneumoniae Antibodies in Healthy Residents of Jeonnam Province / 대한임상미생물학회지

BACKGROUND: Mycoplasma pneumoniae is the most frequent cause of respiratory tract infections in schoolaged children and adolescents. For appropriate use of antibiotics, diagnosis of M. pneumoniae infection in routine clinical practice has been based on serology using a single serum sample. We evaluated the seroprevalence of anti-M. pneumoniae-specific antibodies in 500 asymptomatic, healthy persons in Jeonnam Province. METHODS: Sera were collected from 500 healthy persons in Jeonnam Province. Anti-M. pneumoniae antibody titer was measured using a microparticle agglutination assay Serodia Myco II (Fujirebio, Japan) and VIRCELL IgM Mycoplasma ELISA kits (Vircell, Granada, Spain). RESULTS: Anti-M. pneumoniae antibody titers in 500 healthy individuals were 1:20 in 344 (68.8%), 1:40 in 16 (3.2%), 1:80 in 71 (14.2%), 1:160 in 45 (9.0%), 1:320 in 14 (2.8%), and 1:160) and positive IgM, and an assessment of current infection with single serum serology has its limitation for the diagnosis of M. pneumoniae infections.

National Early Warning System Construction for Timely Surveillance of Foodborne Disease Outbreaks-PulseNet Korea / 감염과화학요법

Foodborne illnesses and big outbreaks have been increased because of the widespread of lunch distribution at school, mass production of food products, and international food trades. It is important to find the origin of contamination by various pathogens in an early stage of the outbreaks for the disease control and prevention. For the purpose of construction of the early warning system, Korea National Institute of Health (KNIH) inaugurated PulseNet Korea in 2005. The organization of PulseNet Korea consists of KNIH as a center and the participating laboratories including Korea Food & Drug Administration (KFDA), National Veterinary Research & Quarantine Station (NVRQS), and regional Institutes of Health & Environment. PulseNet Korea has focused on training researchers from participating laboratories as well as playing an important role in PulseNet International. In this review, PulseNet Korea construction is introduced as a national early warning system for timely surveillance of foodborne diseases.

National Early Warning System Construction for Timely Surveillance of Foodborne Disease Outbreaks-PulseNet Korea / 감염과화학요법

Foodborne illnesses and big outbreaks have been increased because of the widespread of lunch distribution at school, mass production of food products, and international food trades. It is important to find the origin of contamination by various pathogens in an early stage of the outbreaks for the disease control and prevention. For the purpose of construction of the early warning system, Korea National Institute of Health (KNIH) inaugurated PulseNet Korea in 2005. The organization of PulseNet Korea consists of KNIH as a center and the participating laboratories including Korea Food & Drug Administration (KFDA), National Veterinary Research & Quarantine Station (NVRQS), and regional Institutes of Health & Environment. PulseNet Korea has focused on training researchers from participating laboratories as well as playing an important role in PulseNet International. In this review, PulseNet Korea construction is introduced as a national early warning system for timely surveillance of foodborne diseases.

Rapid Serological Identification for Monophasic Salmonella Serovars with a hin Gene: Specific Polymerase Chain Reaction

Salmonellosis is one of the most common food born diseases in Korea. However, it takes more than 8 days and many expensive antiserums are used for the identification of Salmonella serovars since the microorganism easily undergoes phase variation. According to the data that 65.5% of Salmonella isolates in 2000~2004 year had monophasic flagella, we have developed a rapid serological identification method using a hin gene-specific polymerase chain reaction (PCR) for monophasic Salmonella isolates that does not require the time-consuming phase conversion experiments. Using our new method, 'hin specific PCR-based serological test', we could identify serovars of monophasic Salmonella in 4 days. For the purpose of rapid identification of salmonella serovars collected from outbreaks and sporadic cases, hin specific PCR-based serological tests will be a fast and efficient method.

A Virulent Strain of Salmonella enterica Serovar London Isolated in Infants with Enteritis Traced by Active Surveillance and Molecular Epidemiological Study

A total of 74 isolates of Salmonella enterica serovar London were collected through the Laboratory-Based Diarrheal Diseases Surveillance in 2000-2001. In order to characterize the isolates and investigate the source of the epidemic, we performed antimicrobial susceptibility tests and XbaI Pulsed-field gel electrophoresis (PFGE) of 44 Salmonella London isolates. Forty isolates were from feces of infants and four isolates were from adults aged 30, 52, 54, and 59 yr. Two subtypes were identified: a tetracycline-susceptible A 0 PFGE pattern and a tetracyclineresistant A 1 PFGE pattern. Interestingly, the isolates from all infants and one 30-yr-old adult were A 0 PFGE pattern and tetracycline-susceptible. Furthermore, the A 0 PFGE pattern strain was approximately 2 times more virulent than the A 1 PFGE pattern strain, according to the results of in vitro invasion assay using J774A.1 macrophage-like cells. These results indicate that the active surveillance with molecular epidemiological tools would be valuable for promptly finding new epidemic strains. Our results also suggested that the virulent Salmonella London strain might infect the infants through a common contaminated source.

Epidemiological Characterization of Shigella flexneri Isolates in Korea and the Analysis of Pulsed - Field Gel Electrophoresis Patterns

We investigated the molecular epidemiological characteristics of the Shigella flexneri strains primarily isolated in the provincial health center from 1998 to 1999. Among 289 isolates of S. flexneri, 270 isolates (93A%) were confirmed as S. flexneri serotype 2a. The monthly isolation rate of S. flexneri strains was different from that of S, sonnei. S. flexneri strains were not isolated from July to August in 1998 but were isolated rarely during the same period in 1999. Shigella strains were isolated at higher rates in the areas of Chungbuk (64.4%), Busan (8.2%), Jeonnam (6.8%) in 1998 and in the areas of Busan (10.6%), Gangwon (9.3%), Gyeongnam (29.2%), Jeonbuk (4.2%) and Jeonnam (20.8%) in 1999. In these areas, the large outbreaks occurred with relatively high isolation rates of Shigella strain. Among 289 strains, 172 (59.5%) S. flexneri strains were isolated from female patients. Eighty-eight (30.4%) Shigella strains were isolated among the high risk age group of over 61 years. With the antimicrobial susceptibility tests, 284 isolates (98.3%) showed multiple resistance to more than four antibiotics, but all isolates were sensitive to ciprofloxacin, ceftriaxone and cefoxitin. We could divide on isolates into 5 groups (A, B, C, D and E) by analyzing PFGE patterns. Group A subdivided as 16 subgroups and 270 (93.4%) strains belong to the group A. The PFGE patterns of strains isolated from outbreaks revealed that the was only little difference corresponding one to three bands among strains. This result indicates that our isolates are genetically related.

Serogroup and Verocytotoxin Productivity of Escherichia coli Isolated from Diarrheal Patients in Korea / 감염

BACKGROUND: Since 1982, many countries has reported outbreaks or sporadic cases caused by enterohaemorrhagic Escherichia coli (EHEC) serogroup strains, mainly E. coli O157:H7 type strain. However, systemic investigation about EHEC agents, including E. coli O157:H7, have not been done in Korea. Therefore, we investigated serogroup and verotoxin productivity of E. coli strains isolated from diarrheal patients and estimated risk of human infection in comparison with the EHEC strains isolated from cow, pig, and food material in Korea. METHODS: Diarrheal patient stool samples were collected and E. coli strains were isolated, according to biochemical characteristics. In order to isolate E. coli O157:H7, D-Sorbitol negative E. coli strains were selected. Serogrouping of the E. coli isolates was done by agglutination test. Verocytotoxin productivity was investigated by polymerase chain reaction (PCR) and reversed passive latex agglutination (RPLA). Human infection risk was estimated in comparison with EHEC strains isolated from cow, pig and food materials in Korea. RESULTS: Twenty-five E. coli strains were isolated from the diarrheal patients who were suspected to be infected with EHEC. However, none of these E. coli strains produced verocytotoxin. Out of 25 E. coli isolates, 16 serogroups of E. coli O1, O6, O8, O15, O20, O25, O26, O28, O29, O44, O86a, O119, O126, O128, O152 and 157:H- were found. In each of the E. coli O157:H- and O25 serogrorps 3 strains were found. CONCLUSION: None of 25 E. coli isolated from diarrheal patients who were suspected of EHEC infection produced verocytotoxin producing E. coli have been reported recently in Korea.

An Outbreak of Food Poisoning by Salmonella senftenberg / 감염

Salmonella senf tenberg is an uncommon serotype and was first isolated in 1928. Recently, its increasing rate of isolation from human sources, especially from infants and neonates in hospital environments, has suggested it as an important pathogen in other countries. It has been isolated sporadically from the stool of patients with diarrhea but there has been no report of outbreak by S. senf tenberg in Korea. We report an outbreak by S. senf tenberg affecting 104 patients. S. senf tenberg was isolated from pork meat left for a long time at room temperature. The incubation period was 9 to 12 hours. Predominant symptoms were diarrhea (90%), fever (74.4 %), abdominal pain (55.1%), nausea (42.2%), and vomiting (28.9%). Mean peripheral leukocyte count was 11,413 (+/-3,037)/mm 3 and 82 (+/-9.8) % of neutrophils were of segmented form. S. senf tenberg was isolated from the stool of 31 patients among 90 patients. Most of the patients improved within 2 to 5 days with quinolone and intravenous fluid therapy.