• Pediatric Infection and Vaccine
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• v.29 no.2
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• pp.70-76
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• 2022

Coronavirus disease 2019 (COVID-19) in patients with underlying diseases, is associated with high infection and mortality rates, which may result in acute respiratory distress syndrome and death. Mucopolysaccharidosis (MPS) type II is a progressive metabolic disorder that stems from cellular accumulation of the glycosaminoglycans, heparan, and dermatan sulfate. Upper and lower airway obstruction and restrictive pulmonary diseases are common complaints of patients with MPS, and respiratory infections of bacterial or viral origin could result in fatal outcomes. We report a case of COVID-19 in a 16-year-old adolescent with MPS type II, who had been treated with idursulfase since 5 years of age. Prior to infection, the patient's clinical history included developmental delays, abdominal distension, snoring, and facial dysmorphism. His primary complaints at the time of admission included rhinorrhea, cough, and sputum without fever or increased oxygen demand. His heart rate, respiratory rate, and oxygen saturation were within the normal biological reference intervals, and chest radiography revealed no signs of pneumonia. Consequently, supportive therapy and quarantine were recommended. The patient experienced an uneventful course of COVID-19 despite underlying MPS type II, which may be the result of an unfavorable host cell environment and changes in expression patterns of proteins involved in interactions with viral proteins. Moreover, elevated serum heparan sulfate in patients with MPS may compete with cell surface heparan sulfate, which is essential for successful interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the host cell surface, thereby protecting against intracellular penetration by SARS-CoV-2.

• Journal of Life Science
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• v.33 no.1
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• pp.91-101
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• 2023

Bacteriocins are antimicrobial peptides synthesized on ribosomes, produced by bacteria, that inhibit the growth of similar or closely related bacterial strains. Since the discovery of nisin, many bacteriocins with unique structures and various modes of antibacterial activity have been described, and genes encoding production, secretion, and immunity have been reported. Nisin is one of the bacteriocins applied in cheese, liquid eggs, sauces and canned foods. Many of the bacteriocins of the genus Bacillus belong to lantibiotics, which are modified peptides after translation. Other genus Bacillus also produce many non-lantibiotic bacteriocins. Bacteriocins of the genus Bacillus are sometimes becoming more important because of their broader antibacterial spectrum. Bacteriocins are considered attractive compounds in the food and pharmaceutical industries to prevent food spoilage and growth of pathogenic bacteria. Bacteriocins can be used as biological preservatives in a variety of ways in the food system. Biopreservation refers to extending shelf life and improving safety of foods using microorganisms and/or their metabolites. The demand for new antimicrobial compounds has generated great interest in new technologies that can improve food microbiological safety. Applications of bacteriocins are expanding from food to human health. Today, many researchers are shifting their interest in bacteriocins from food preservation to the treatment of bacteria that cause infections and antibiotic-resistant diseases. This exciting new era in bacteriocin research will undoubtedly lead to new inventions and new applications. In this review, we summarize the various properties and applications of bacteriocins produced by the genus Bacillus.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.239-248
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• 2022

The taxonomy of bacteria in the field of clinical microbiology is in a state of constant flux. A large-scale revamping of the classification and nomenclature of anaerobic bacteria has taken place over the past few decades, mainly due to advances in molecular techniques such as 16S rRNA and whole genome sequencing (WGS). New genera and species have been added, and existing genera and species have been reclassified or renamed. A major role of the clinical microbiological laboratories (CMLs) is the accurate identification (ID) and appropriate antimicrobial susceptibility testing (AST) for clinically important bacteria, and rapid reporting and communication of the same to the clinician. Taxonomic changes in anaerobic bacteria could potentially affect the choice of appropriate antimicrobial agents and the antimicrobial breakpoints to use. Furthermore, current taxonomy is important to prevent treatment failures of emerging pathogenic anaerobes with antimicrobial resistance. Therefore, CMLs should periodically update themselves on the changes in the taxonomy of anaerobic bacteria and suitably inform clinicians of these changes for optimum patient care. This article presents an update on the taxonomy of clinically important anaerobic bacteria, together with the previous names or synonyms. This taxonomy update can help guide antimicrobial therapy for anaerobic bacterial infections and prevent treatment failure and can be a useful tool for both CMLs and clinicians.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.244-252
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• 2023

The timeliness and accuracy of test results are crucial factors for clinicians to decide and promptly administer effective and targeted antimicrobial therapy, especially in life-threatening infections or when vital organs and functions, such as sight, are at risk. Further research is needed to refine and optimize matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based assays to obtain accurate and reliable results in the shortest time possible. MALDI-TOF MS-based bacterial identification focuses primarily on techniques for isolating and purifying pathogens from clinical samples, the expansion of spectral libraries, and the upgrading of software. As technology advances, many MALDI-based microbial identification databases and systems have been licensed and put into clinical use. Nevertheless, it is still necessary to develop MALDI-TOF MS-based antimicrobial-resistance analysis for comprehensive clinical microbiology characterization. The important applications of MALDI-TOF MS in clinical research include specific application categories, common analytes, main methods, limitations, and solutions. In order to utilize clinical microbiology laboratories, it is essential to secure expertise through education and training of clinical laboratory scientists, and database construction and experience must be maximized. In the future, MALDI-TOF mass spectrometry is expected to be applied in various fields through the use of more powerful databases.

• Journal of the Korean Society of Radiology
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• v.81 no.4
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• pp.990-995
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• 2020

Chronic granulomatous disease (CGD) is an uncommon primary immune deficiency caused by phagocytes defective in oxygen metabolite production. It results in recurrent bacterial or fungal infections. Herein, we present a case of CGD with a large pulmonary granuloma in a neonate and review the imaging findings. The patient was a 24-day-old neonate admitted to the hospital with fever. A round opacified lesion was identified on the chest radiograph. Subsequent CT and MRI revealed a round mass with heterogeneous enhancement in the right lower lobe. There were foci of diffusion restriction in the mass. Surgical biopsy of the mass revealed chronic granuloma. Finally, the neonate was diagnosed with CGD caused by mutation of the gp91^phox gene. Herein, we present the clinical and imaging findings of this unusual case of CGD.

• Journal of Veterinary Clinics
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• v.10 no.2
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• pp.171-184
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• 1993

In Seoul area, there are so many kennel clubs, veterinary hospital, pet establishment and breeding confers that various problems have occurred. They are crowed pet houses, poor sanitation, stress to puppies, sudden environmental changes to puppies and unvaccination against parvovirus, canine distemper virus, parainfluenza virus, infectious hepatitis caused by Adenovirus type I and Leptospira. Several studies were made to survey the infectious agents involved in acute diarrhea of poppies in Seoul are, such as history taking, physical examination, complete blood count and serum chemistry, histopathological finding, bacterial isolation and identification, and hemagglutination test in feces and hemagglutination inhibition test in serum against parvovirus, respectively. The results obtained are summarized as followed. 1. The percent of PCV (30.5$\pm$5.6) and concentration of Total protein(5.0$\pm$0.8) resulted from statistical analysis are significantly lower than normal values (p<0.05), respectively. In addition, fibrinogen (505$\pm$326) was significantly higher an normal value (p<0.001), Band neutrophil (22.9$\pm$12.7) showed signifiant difference (P<0.01). decreased monocyte (3.2$\pm$2.1) and eosinophil (0.7$\pm$0.8) values appeared statistically significant (p<0.001), lymphocyte (16.7$\pm$9), as well. 2. The concentrations of calcium .(8.0$\pm$2.8), glucose (40.1$\pm$31.4), and albumin (2.0$\pm$0.39) were lower than normal values (p<0.01, p<0.01, p<0.001), respectively. Also Inorganic phosphate (7.1$\pm$2.4), pH (p<7.9f:0.2), and Blood Urea Nitrogen (40.41=37.1) were significantly higher than normal values (p<0.001, p(0.001, p<0.05), respectively. 3. Simple and mixed infections occupied 18% and 82% in the distribution of causes in puppies with acute diarrhea, respectively. 4. As puppies got older, incidence of acute diarrhea caused by Staphylococcus aureus was decreased to 13% and infection of canine distemper virus was increased to 53%, but E coli and canine parvovirus always showed high frequency of outbreak in the body weight ranged from 35g to 7.8Kg. 5. As showed in table 5, infections of E coli and Canine Parvovirus showed high outbreak regardless of the age which is classified into three stages, 35~50 day, 60 day and 75~day to 1 year, canine distemper virus appeared increased, but in case of Staphylococcus aureus, visa versa. 6. In comparison wi methods for the laboratory diagnosis diagnosis parvovirus, Hemagglutination test showed positive reaction in 25% and mean serum antibody titer measured by Hemagglutination inhibition test showed 2779 (n=20). In addition, positive reaction was 90% (18/20). 7. In histopathological studies, enteritic and pneumonic lesions were indicated in 53.7% and 39.5% of samples, respectively. 8. Etiologic diagnosis based on the history taking, clinical signs and histopathological findings in puppies with acute diarrhea and vomiting indicated that 50% of puppies were infected by canine parvovirus and distemper virus. 9. In the parasitological examination made by simple flotation with saturated zinc sulfate tour parasites found were Isospora canis, Toxocara canis, Ancylostoma spp and Toxocara spp. Isospora canis and Toxocara canis were more frequently found among those parasites of diarrhoeic causes in puppies ranged from 35 days to 1 year. Their infestation rates were 15% and 13% respectively.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.178-185
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• 2005

Purpose : Ocular adnexal and orbital infections are broadly divided into preseptal(periorbital) and postseptal(orbital) cellulitis by orbital septum. In this study, we investigated the difference between periorbital and orbital cellulitis regarding their pathogenesis, clinical manifestations, treatments, and prognosis. Methods : We reviewed medical records of 50 cases who were hospitalized in the Severance hospital due to orbital cellulitis from May 1995 to April 2004. Results : There were 32 males and 18 females. The mean age was $3.2{\pm}3.5$ year. According to the result of orbital computerized tomography, 36 cases were periorbital cellulitis, 10 cases orbital cellulitis and 4 cases not diagnosed. The clinical manifestations of periorbital cellulitis are periorbital swelling(100%), fever(19%), orbital pain(6%), and chemosis(22%). On the other hand, those of orbital cellulitis are periorbital swelling(100%), fever(80%), orbital pain(60%), proptosis(20%), chemosis(70%) and limitation of eye movement(20%). The etiologies of periorbital cellulitis are sinusitis(14%), upper respiratory infection(8%), conjunctivitis (19%), skin wound(14%) and unknown(44%). The etiologies of orbital cellulitis are sinusitis (50%), upper respiratory infection(20%), and unknown(30%). The first line antibiotics used in the majority of cases were combinations of cefoxitin+aminoglycoside. 5 patients with orbital cellulitis taking cefoxitin+aminoglycoside had to change the medication into vancomycin or clindamycin. 3 patients with orbital cellulitis underwent operation while 1 patient developed bacterial meningitis. Conclusion : According to invasion of orbit, ocular adnexal and orbital infections are quite different in their pathogenesis, treatment and prognosis. As atypical cases may confound the diagnosis, prompt orbital computerized tomography is required for an accurate diagnosis.

• Pediatric Infection and Vaccine
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• v.21 no.2
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• pp.96-103
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• 2014

Purpose: The aim of this study is that the prevalence of rotavirus infection was evaluated by each group and clinical features of group A, B and C rotaviruses infections were described respectively to compare one with another. Methods: Between January 2010 and December 2010, we enrolled a group of children below 10 years of age admitted for management of acute diarrhea at the Catholic University of Korea Bucheon St. Mary's Hospital. A total of 310 stool samples documented to be free of common bacterial pathogens were collected from children with diarrhea. The presence of group A, B or C rotavirus is indicated by amplification of DNA segments of the expected lengths after the first and second PCRs Results: In a total of 310 stool specimens, 40 (12.9%) specimens were positive for rotaviruses. These included 23 (7.4%) positive for group A, 5 (1.6%) for group B and 12 (3.9%) for group C rotaviruses. Group B rotavirus infected patients had significantly less diarrheas per day (group A: P =0.01, group C: P =0.01) and shorter duration of vomiting days (group A: P =0.03, group C: P =0.03) than those with group A and C rotaviruses infection respectively. All the group B rotaviruses had been isolated in March and October. Group C rotavirus infections were prevalent during late summer and early winter and peaked in October. Conclusion: These findings indicate that group B and C rotaviruses are notable causes or the contributing causes of diarrhea among infants and children in Korea.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.162-166
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• 2009

Purpose : Urinary tract infection (UTI) is one of the most common bacterial infectious disease in childhood. Renal scarring is an important complication of UTIs. Known risk factors for renal scarring are younger age, anatomic defects, delayed treatment, and causative pathogens other than Escherichia coli. The aim of this study was to compare the characteristics of clinical and laboratory features of UTI with E. coli to those with non-E. coli in infants. Methods : We reviewed the medical records of 1,120 infants under 12 months of age who had been admitted for UTIs between January 1998 and December 2007. All patients who were diagnosed with UTIs were divided into two groups (E. coli and non-E. coli UTIs). Results : Three hundred twenty-four of 1,120 cases met the inclusion criteria. The number of E. coli and non-E. coli UTIs was 273 (84.3%) and 51 (15.7%), respectively. As compared to the non-E. coli UTI group, the E. coli UTI group was younger (3.59 vs. 4.47 months, P =0.008), a longer duration of pyuria (3.96 vs. 3.06 days, P =0.01), higher peripheral white blood cell counts (13.89 vs. $12.13{\times}10^3/mm^3$, P =0.043), and lower rates of high degree (III-V) vesico-ureteral reflux (P =0.005). Conclusion : UTIs with E. coli might have more severe clinical features and a lower prevalence of high grade vesicoureteral reflux than UTIs with non-E. coli. However, no difference was noted in the clinical response to antibiotic therapy between the two groups.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.240-247
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• 2010

Pseudomonas aeruginosa is a Gram (-) opportunistic human pathogen causing a wide variety of infections on lung, urinary tract, eyes, and burn wound sites and quorum sensing (QS), a cell density-sensing mechanism plays an essential role in Pseudomonas pathogenesis. In order to investigate the importance of QS in the Pseudomonas infections of Korean patients, we isolated 189 clinical strains of P. aeruginosa from the patients in Pusan Paik Hospital, Busan, South Korea. The QS signal production of these clinical isolates was measured by signal diffusion assay on solid media using reporter strains. While most clinical strains (79.4%) produced the QS signals as similar level as a wild type strain, PAO1 did, where LasR, the initial QS signal sensor-regulator was fully activated, a minority of them (4.2%) produced much less QS signals at the level to which LasR failed to respond. Similarly, while 72.5% of the clinical isolates produced QS signals enough to activate QscR, an another QS signal sensor-regulator, some few of them (9%) produced the QS signals at much lower level where QscR was not activated. For further analysis, we selected 74 clinical strains that were obtained from the patients under suspicion of Pseudomonas infection and investigated the total protease activity that is considered important for virulence. Interestingly, significant portion of them showed very low protease activity (44.6%) or no detectable protease activity (12.2%). When the biofilm-forming ability that is considered very important in chronic infection was examined, most isolates showed lower biofilm-forming activity than PAO1. Similarly, significant portion of clinical isolates showed reduced motility (reduced swarming activity in 51.4% and reduced twitching activity in 41.9%), or non-detectable motility (swarming-negative in 28.4% and twitching-negative in 28.4%). Our result showed that the clinical isolates that produced QS signals at the similar level to wild type could have significantly reduced activities in the protease production, biofilm formation, and motility, and some clinical isolates had unique patterns of motility, biofilm formation, and protease production that are not correlated to their QS activity.