Epidemiological analysis and prevention strategies in response to a shigellosis cluster outbreak: a retrospective case series in an alternative school in the Republic of Korea, 2023

Objectives@#In March 2023, an alternative school in the Republic of Korea reported 12 cases of shigellosis. This study aims to analyze the epidemiological characteristics in order to determine the cause of the cluster outbreak of shigellosis and to develop prevention strategies. @*Methods@#This study focused on 12 patients with confirmed Shigella infection and investigated their demographics, clinical features, epidemiology, diagnostics, and antimicrobial susceptibility. Following the identification of Shigella, we conducted follow-up rectal smear cultures to manage patients, implementing isolation and control measures. @*Results@#This study investigated the emergence of multidrug-resistant Shigella following missionary activities in Cambodia, documenting a cluster infection within an alternative school in Daejeon, the Republic of Korea. The outbreak affected 56 participants, resulting in the confirmation of 12 cases. The incidence rates varied by gender and occupation, with higher rates among males and teachers. All 12 cases demonstrated multidrug resistance. Challenges included delayed pathogen confirmation and suboptimal adherence to isolation criteria. The incident prompted revisions in the criteria for isolation release, focusing on symptom resolution. The study underscores the necessity for strengthened surveillance, educational initiatives focusing on prevention in endemic areas, and improved oversight of unlicensed educational establishments. @*Conclusion@#Successful response strategies included swift situation assessment, collaborative efforts, effective infection control measures, and modified criteria for isolation release. Continued surveillance of multidrug-resistant strains is recommended, especially in regions with a high prevalence.

Successful mitral repair in dogs by mitral annuloplasty using Hegar dilator: two case reports

Mitral regurgitation (MR) is the most common heart disease in small-breed dogs. Mitral repair, which comprise artificial chorda tendineae implantation and mitral annuloplasty, has become the mainstay of treatment in the veterinary field. We report on two small dogs who underwent mitral repair surgery for MR. A Hegar dilator was used during mitral annuloplasty for accurate and reproducible surgery. In both cases, mitral regurgitant flow almost disappeared after surgery, and clinical signs improved. The treatment regimen was terminated 3 months after the surgery. We concluded that using a Hegar dilator may facilitate mitral valve repair surgery.

Genomic Surveillance of SARS-CoV-2: Distribution of Clades in the Republic of Korea in 2020

Since a novel beta-coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in December 2019, there has been a rapid global spread of the virus. Genomic surveillance was conducted on samples isolated from infected individuals to monitor the spread of genetic variants of SARS-CoV-2 in Korea. The Korea Disease Control and Prevention Agency performed whole genome sequencing of SARS-CoV-2 in Korea for 1 year (January 2020 to January 2021). A total of 2,488 SARSCoV-2 cases were sequenced (including 648 cases from abroad). Initially, the prevalent clades of SARSCoV-2 were the S and V clades, however, by March 2020, GH clade was the most dominant. Only international travelers were identified as having G or GR clades, and since the first variant 501Y.V1 was identified (from a traveler from the United Kingdom on December 22 nd , 2020), a total of 27 variants of 501Y.V1, 501Y.V2, and 484K.V2 have been classified (as of January 25 th , 2021). The results in this study indicated that quarantining of travelers entering Korea successfully prevented dissemination of the SARS-CoV-2 variants in Korea.

New Approach in the Treatment of Intertrochanteric Fracture Using a Cephalomedullary Nail / 대한정형외과학회잡지

A gamma nail has been used to treat intertrochanteric fractures since 1988. Although such cephalomedullary nails have mechanical advantages over extramedullary fixation devices, such as sliding hip screw, their beneficial effects on treating the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 31-A1 and 31-A2 fractures are still controversial. During their 30- year history, many problems have been overcome, and new types of cephalomedullary nails have been introduced in clinical practice. New cephalomedullary nail systems facilitate nailing procedures and enhance the purchase capability of the femoral head by a lag screw. On the other hand, the failure rate still depends on the hands of the orthopedic surgeons. This review article focused on the basic principle of medial support and restoration of a medial buttress during the treatment of trochanteric fractures using a cephalomedullary nail.

Visual Field Defect after Taking Atorvastatin/Ezetimibe, a Case Study

Atorvastatin is one of the most widely prescribed medications for dyslipidemia treatment. In Korea, post combined therapy with ezetimibe, a 73-year-old woman was reported by a community pharmacy to have experienced visual field defect, which recovered after drug discontinuation. She had never experienced this symptom before, and several studies have reported an association between use of statins and visual disorders such as blurred vision, diplopia, and cataract. Blockage of cholesterol accumulation, oxidative stress, or myopathy is expected to be a cause of this symptom. Naranjo scale, Korean causality assessment algorithm (Ver.2), and World Health Organization-Uppsala Monitoring Center (WHO-UMC) criteria were the three tools used to determine causality between the visual disorder and atorvastatin. The results represent ‘probable’, ‘certain’, and ‘probable/likely’ causality, respectively. Our results, in combination with a review of literature, indicate that ocular adverse effects are highly likely related to atorvastatin.

Long-term Outcomes of Cemented Total Hip Arthroplasty in Patients with Ankylosing Spondylitis at a Minimum Follow-up of 10 Years / 대한고관절학회지

PURPOSE: This study was performed to evaluate long-term clinical and radiologic outcomes of cemented total hip arthroplasty in patients with ankylosing spondylitis. MATERIALS AND METHODS: A retrospective study of 12 patients (16 cases) diagnosed with ankylosing spondylitis undergoing total hip arthroplasty with cemented femoral stem from November 2002 to January 2006 with a minimum follow up of 10 years. Clinical outcomes were assessed using Harris Hip Scores and measures of pain and range of motion. Radiologic outcomes were assessed with serial plain X-ray. Fixation and stability of implant, enthesopathy of ischium and development of heterotopic ossification were also evaluated. RESULTS: Mean Harris Hip Scores significantly improved from pre-operative levels (58 points; range, 39–81 points) to post-operative (92 points; range, 68–100 points). Mean flexion contracture levels decreased from preoperative (13°) to post-operative (5°), and mean post-operative range of motion improved 106° compared to preoperative levels. No newly developed osteolysis lesions or implant loosening were observed in last follow up X-rays. One heterotopic ossification and one greater trochanter fracture were observed. Greater trochanter fracture was treated conservatively, and was resulted in bony union. No patients underwent revisions. CONCLUSION: This study revealed positive long-term clinical and radiologic outcomes following total hip arthroplasty with cemented femoral stems in patients with ankylosing spondylitis patients.

Infection of Extended-Spectrum β-Lactamase Producing Shigella flexneri in Children Attending a Childcare Center in Korea

Shigella is a common cause of bacterial enteritis worldwide. Shigella sonnei accounts for 90% of Shigella infections and Shigella flexneri is rarely reported in Korea. Although the incidence of Shigella infection has decreased, the incidence of organisms with antibiotic resistance has gradually increased in Korea. An outbreak of extended-spectrum β-lactamase (ESBL)-producing S. sonnei in children was reported in Korea; however, ESBL-producing S. flexneri has not yet been reported. We report the first two cases of multidrug-resistant CTX-M-14-producing S. flexneri infections in Korean children.

Characterization of Salmonella spp. Clinical Isolates in Gyeongsangbuk-do Province, 2012 to 2013 / 대한임상미생물학회지

BACKGROUND: Extended-spectrum cephalosporins and fluoroquinolones are important antimicrobials for treating invasive salmonellosis, and emerging resistance to these antimicrobials is of paramount concern. METHODS: A total of 30 Salmonella spp. clinical isolates recovered in Gyeongsangbuk-do from 2012 to 2013 were characterized using antibiotic resistance profiles and pulsed-field gel electrophoresis (PFGE). RESULTS: A high prevalence of multidrug-resistant isolates, mainly showing an ampicillin, nalidixic acid, chloramphenicol resistance pattern, was observed. Four extended-spectrum beta-lactamase (ESBL)-producing isolates (3 CTX-M-15 isolates and 1 CTX-M-27 isolate) were found. The bla(CTX-M-27) gene was carried by an IncF conjugative plasmid in the S. Infantis isolate. The bla(CTX-M-15) gene were carried by an IncF (2 isolates) or IncHI2 (1 isolate) conjugative plasmid in S. Enteritidis. In addition, a single mutation of GyrA, Ser83Thr (1 isolates), Asp87Tyr (9 isolates), Asp87Gly (4 isolates), and Asp87Leu (3 isolates), was detected in nalidixic acid-resistant Salmonella spp. isolates. XbaI PFGE analysis of all isolates revealed more than 19 different pulsotypes. The most common S. Enteritidis PFGE pattern (SEGX01.003) was associated with a larger number of cases of invasive salmonellosis than all other patterns. CONCLUSION: The information from our study can assist in source attribution, outbreak investigations, and tailoring of interventions to maximize disease prevention.

Genetic Characteristics and Relatedness of Imported Vibrio cholerae O1 Biotype El Tor in Korea / 대한임상미생물학회지

BACKGROUND: Cholera is a representative water-borne disease that is caused by V. cholera ctx (+). V. cholera El Tor was previously the primary pathogen, but after the seventh pandemic outbreak, it was replaced by a V. cholera El Tor variant with a classical phenotype and genotype. In this study, we investigated the genotypic and phenotypic characteristics of imported V. cholerae El Tor in Korea. METHODS: Forty-nine V. cholerae O1 El Tor strains isolated from 2004 to 2011 were used in this study. Polymerase chain reaction amplification of the ctxB and rstR genes was used for biotype determination. An antimicrobial susceptibility test was performed for phenotypic analysis, and pulse field gel electrophoresis (PFGE) was used for analysis of genetic relatedness. RESULTS: Classical ctxB genes were found in all of the isolates, while classical, El Tor, and combined rstR genes were found. Twenty strains showed antimicrobial resistance against streptomycin, sulfamethoxazole/trimethoprim, nalidixic acid, and ciprofloxacin. Based on PFGE, all isolates were grouped as cluster B. The country of origin and resistance pattern were highly related, although the time of influx and serogroup were not. CONCLUSION: Isolates of V. cholera El Tor imported since 2004 were hybrids of V. cholera El Tor, which has the classical ctxB gene and is considered to be a CTX prophage. The SXT element plays an important role in antimicrobial resistance. PFGE patterns, which can be used for analysis of imported V. cholera, revealed the relatedness of the resistant isolates.

Quinolone-resistant Shigella flexneri Isolated in a Patient Who Travelled to India

We report a recent case in which ciprofloxacin-resistant Shigella flexneri was isolated from a 23-yr-old female patient with a history of travel to India. Prior to her admission to our internal medicine department, she experienced symptoms of high fever and generalized weakness from continuous watery diarrhea that developed midway during the trip. S. flexneri was isolated from the stool culture. Despite initial treatment with ciprofloxacin, the stool cultures continued to show S. flexneri growth. In the susceptibility test for antibiotics of the quinolone family, the isolate showed resistance to ciprofloxacin (minimum inhibitory concentration [MIC], 8 microg/mL), norfloxacin (MIC, 32 microg/mL), ofloxacin (MIC, 8 microg/mL), nalidixic acid (MIC, 256 microg/mL), and intermediate resistance to levofloxacin (MIC, 4 microg/mL). In molecular studies for quinolone resistance related genes, plasmid borne-quinolone resistance genes such as qnrA, qnrB, qnrS, aac(6')-Ib-cr, qepA, and oqxAB were not detected. Two mutations were observed in gyrA (248C-->T, 259G-->A) and 1 mutation in parC (239G-->T). The molecular characteristics of the isolated S. flexneri showed that the isolate was more similar to the strains isolated from the dysentery outbreak in India than those isolated from Korea.

Contrast-enhanced ultrasound analysis of renal perfusion in normal micropigs

Contrast-enhanced ultrasound is one of method for evaluating renal perfusion. The purpose of this project was to assess perfusion patterns and dynamics in normal micropig kidney using ultrasonographic contrast media. Eight young healthy micropigs were included in this study. Micropigs were anesthetized with propofol and received an intravenous bolus of microbubble contrast media through an ear vein. Time/mean pixel value (MPV) curves were generated for selected regions in the right renal cortex and medulla. The parenchyma was enhanced in two phases. The cortex was first enhanced followed by a more gradual enhancement of the medulla. A significant difference in perfusion was detected between the cortex and medulla. Following the bolus injection, the average upslope was 0.68 +/- 0.27 MPV/sec, downslope was -0.27 +/- 0.13 MPV/sec, baseline was 73.9 +/- 16.5 MPV, peak was 84.6 +/- 17.2 MPV, and time-to-peak (from injection) was 17.5 +/- 6.6 sec for the cortex. For the medulla, the average upslope was 0.50 +/- 0.24 MPV/sec, downslope was -0.12 +/- 0.06 MPV/sec, baseline was 52.7 +/- 7.0 MPV, peak was 65.2 +/- 9.3 MPV, and time-to-peak (from injection) was 27.5 +/- 5.0 sec. These data can be used as normal reference values for studying young micropigs.

Evaluation of the lateral ventricle using MRI in normal micropigs / 대한수의학회지

This study was undertaken to assess the lateral ventricle, which was some portion of brain and related to congenital anomalies, from 1, 2, 4, and 8 months of age in healthy micropigs. They were induced general anesthesia and performed magnetic resonance imaging (MRI) with a 0.3 Tesla magnet. Each age group was evaluated by three subjects such as lateral ventricular volume, ventricular volume ratio and asymmetry. T1 weighted transverse images were acquired for calculation of lateral ventricular and corresponding brain parenchyma areas. The ratio of bilateral ventricle areas used to analyze the asymmetry. The mean ventricular volumes of each month were 676.74 +/- 25.58 mm3 (1 month-old), 630.64 +/- 143.84 mm3 (2 month-old), 992.12 +/- 106.03 mm3 (4 month-old) and 1172.62 +/- 237.57 mm3 (8 month-old), respectively. The ventricular volume ratio was the smallest at 2 month-old and re-increased from that age. The ratio was significantly different between 2 month-old and other age groups (p < 0.05). The value of bilateral area ratio showed within 1.5 in all experimental animals. Consequently the lateral ventricle showed a positive correlation with aging and symmetric shapes in both sides. The developmental pattern of the lateral ventricle provides basic data in micropigs as an experimental animal model for physiological and neurosurgical approach.

Rapid Detection of Extended Spectrum beta-Lactamase (ESBL) for Enterobacteriaceae by use of a Multiplex PCR-based Method / 감염과화학요법

A multiplex PCR method has been developed to classify extended spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC beta-lactamase (PABL). This method consists of the use of two four-multiplex PCRs for the detection of TEM, OXA, SHV, CTX-M, CMY, and DHA type beta-lactamases. We have compared findings from the use of conventional detection methods with that of this newly developed typing method. In testing for 73 ESBL-producing and PABL-producing isolates, 100% of the isolates were correctly identified as previously characterized types and, 44 types of beta-lactamases were additionally identified from 33 isolates. This assay not only reduces the time for classification but also increases the accuracy for detection.

Rapid Detection of Extended Spectrum beta-Lactamase (ESBL) for Enterobacteriaceae by use of a Multiplex PCR-based Method / 감염과화학요법

A multiplex PCR method has been developed to classify extended spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC beta-lactamase (PABL). This method consists of the use of two four-multiplex PCRs for the detection of TEM, OXA, SHV, CTX-M, CMY, and DHA type beta-lactamases. We have compared findings from the use of conventional detection methods with that of this newly developed typing method. In testing for 73 ESBL-producing and PABL-producing isolates, 100% of the isolates were correctly identified as previously characterized types and, 44 types of beta-lactamases were additionally identified from 33 isolates. This assay not only reduces the time for classification but also increases the accuracy for detection.

Detection of the Causative Agents of Traveler's Diarrhea Using a Real-Time PCR Screening Method / 대한임상미생물학회지

BACKGROUND: The incidence of infectious diarrheal disease in Korea has decreased over the past decade, but traveler's diarrhea (TD) is increasing in frequency. We therefore investigated the distribution of the causative agents of TD. METHODS: A total of 132 rectal swab specimens were acquired from TD patients who entered the country via Gimhae International Airport. The specimens were screened for 12 bacterial pathogens by real-time PCR, and target pathogens were isolated from the PCR positive specimens using conventional microbiological isolation methods. RESULTS: A total of 93 specimens (70.5%) showed positive PCR screening results, and of these specimens, nine species and 50 isolates (37.9%), including Vibrio parahaemolyticus (18 isolates) and ETEC (17 isolates), were isolated. No specimens were PCR positive for Listeria monocytogenes or Campylobacter jejuni, and no pathogenic Bacillus cereus were isolated. CONCLUSION: Even though viruses and EAEC were not included as target pathogens, the high isolation rate of these pathogens in this study provides indirect evidence that most cases of pathogen-negative TD are caused by undetected bacterial agents. Furthermore, our study results confirm the effectiveness of real-time PCR-based screening methods. This study is the first report in Korea to demonstrate that ETEC and V. parahaemolyticus are the major causative pathogens of TD, and this knowledge can be used to help treat and prevent TD.

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.

The First Outbreak of Shigellosis Caused by Shigella dysenteriae Type 8 in Korea / 대한임상미생물학회지

BACKGROUND: In May 2004, an outbreak of a diarrheal disease occurred among tourists returning from Mt. Geumgang in North Korea; Shigella dysenteriaetype 8 was isolated from 12 of the 36 patients who were suffering from diarrhea. We investigated the genetic relatedness of the isolates. METHODS: The isolates were identified by VITEK system an serotyped by a slide agglutination test. Antimicrobial susceptibility was determined by the disk diffusion method and genetic relatedness was examined by pulsed-field gel electrophoresis (PFGE). RESULTS: All 12 isolates were identified as Shigella spp., and agglutinated by S. dysenteriae type 8 antisera. All of these isolates showed the same antibiotic susceptibility pattern, and were resistant to streptomycin, tetracycline and trimethoprim/sulfamethoxazole. PFGE patterns were classified into 2 types, sdx1 and sdx2, and the relatedness between these two types was 80.5%. Eleven isolates belonged to sdx1. CONCLUSION: The antibiotic susceptibility pattern and genetic relatedness of the isolates strongly suggest that they were from the same origin. Because this is the first report of S. dysenteriae type 8 isolation in Korea, and all of these cases were related to foreign travel, the surveillance system and the ability of the clinical laboratory should be strengthened to prevent the entry and spread of rare and hitherto not reported infectious agents into Korea.