• 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.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.389-398
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• 2020

The prevalence of carbapenem-resistant Enterobacteriaceae (CRE) is increasing globally, resulting in high mortality rates. Although CRE is a relatively recent problem in Korea (the first case was not diagnosed until 2010), it is responsible for serious morbidities at an alarming rate. In this study, we carried out a molecular genetic analysis to determine the incidence of CRE and carbapenemase-producing Enterobacteriaceae (CPE) at a general hospital in Korea between August 2017 and August 2019. Forty strains of CPE were isolated from various clinical specimens and analyzed via antimicrobial susceptibility testing, polymerase chain reaction to detect β-lactamase genes, deoxyribonucleic acid sequencing, multilocus sequence typing, curing testing, and conjugal transfer of plasmids. The results demonstrated that all 40 isolates were multidrug-resistant. The fluoroquinolone susceptibility test showed that 75% of the Enterobacteriaceae isolates were resistant to ciprofloxacin, whereas 72.5% were resistant to trimethoprim-sulfamethoxazole. Further, conjugation accounted for 57.5% of all resistant plasmid transfer events, which is 4.3-fold higher than that observed in 2010 by Frost et al. Finally, the high detection rate of transposon Tn4401 was associated with the rapid diffusion and evolution of CPE. Our results highlight the rapid emergence of extensively drugresistant strains in Korea and emphasize the need for employing urgent control measures and protocols at the national level.

• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.545-554
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• 2018

Background: The increasing morbidity and mortality rates associated with Acinetobacter baumannii are due to the emergence of drug resistance and the limited treatment options. We compared characteristics of colistin-resistant Acinetobacter baumannii (CR-AB) clinical isolates recovered from patients with and without prior colistin treatment. We assessed whether prior colistin treatment affects the resistance mechanism of CR-AB isolates, mortality rates, and clinical characteristics. Additionally, a proper method for identifying CR-AB was determined. Methods: We collected 36 non-duplicate CR-AB clinical isolates resistant to colistin. Antimicrobial susceptibility testing, Sanger sequencing analysis, molecular typing, lipid A structure analysis, and in vitro synergy testing were performed. Eleven colistin-susceptible AB isolates were used as controls. Results: Despite no differences in clinical characteristics between patients with and without prior colistin treatment, resistance-causing genetic mutations were more frequent in isolates from colistin-treated patients. Distinct mutations were overlooked via the Sanger sequencing method, perhaps because of a masking effect by the colistin-susceptible AB subpopulation of CR-AB isolates lacking genetic mutations. However, modified lipid A analysis revealed colistin resistance peaks, despite the population heterogeneity, and peak levels were significantly different between the groups. Conclusions: Although prior colistin use did not induce clinical or susceptibility differences, we demonstrated that identification of CR-AB by sequencing is insufficient. We propose that population heterogeneity has a masking effect, especially in colistin non-treated patients; therefore, accurate testing methods reflecting physiological alterations of the bacteria, such as phosphoethanolamine-modified lipid A identification by matrix-assisted laser desorption ionization-time of flight, should be employed.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.69-72
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• 2006

Recently sewage facilities mainly consisted of concrete structures are being deteriorated seriously by biodeterioration originated from sulfur-oxidizing bacteria. To prevent biochemical corrosion of the sewage concrete, antibiotics which prevent growth of sulfur-oxidizing bacteria were developed. Existing methods to evaluate properties of biochemical corrosion of concrete examine the antimicrobial performance and resistance to sulfuric acid separately, but don't complexly. So, in this study, new method to test properties of biochemical corrosion of concrete complexly is suggested.

• International Journal of Oral Biology
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• v.38 no.1
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• pp.1-4
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• 2013

Staphylococcus species are one of prevalent pathogens found in hospitals. Microbes that are a primary cause of nosocomial infection were isolated from a dental and medical environment it may assist the reader to explain what this is and how it differs from the 'dental health care providers and ward health care providers'. To investigate the distribution of staphylococcus species in this environment, we used vitek II to measure drug sensitivity, and further performed biochemical testing. The isolation rate of staphylococcus species from the dental and medical environment was 100% but from dental health care providers and ward health care providers were 44.4% and 33.3%, respectively. In the analyses, staphylococcus species showed resistance to diffusion of cefoxitin and oxacillin discs. These staphylococci may be sufficiently positive for the mecA gene. Our results suggest that staphylococci might be an important cause of nosocomial infection in the dental clinic.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.1-5
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• 2009

Methicillin-resistant Staphylococcus aureus (MRSA), a leading cause of nosocomial infections, has been increasingly recognized in communities of the United States. This article will review the clinical spectrum and treatment of MRSA infections in children in the context of recent epidemiological changes of MRSA infections. In general, community-associated (CA) MRSA most frequently causes skin and soft tissue infections and has an increased association with invasive infections, particularly pneumonia and musculoskeletal infections. Hospital-associated (HA) MRSA strains tend to be associated with bloodstream infections, pneumonia, and surgical site infections. Different from the United States, CA-MRSA infections are not common in Korea (only 5.9%); however, there are some CA-MRSA clones that are different from HA-MRSA clones in Korea and from CA-MRSA clones in other countries. The treatment of MRSA infections should be guided by antimicrobial susceptibility testing, the site of infection, and the infection severity. Vancomycin is the treatment of choice for invasive MRSA infections. Other agents such as trimethoprim-sulfamethoxazole, clindamycin, linezolid, quinupristin-dalfopristin, and daptomycin have been used for some conditions.

• Journal of Veterinary Clinics
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• v.37 no.1
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• pp.57-59
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• 2020

A 3-year-old, captive female river cooter was presented with a 4-day history of progressive unilateral swelling of the right side of the head, lethargy, and anorexia. History, physical examination, and radiographic examination revealed an aural abscess. After administration of antibiotics and supportive care, surgical intervention was performed. Swab samples were collected from the tympanic cavity during surgery for cytology and antimicrobial susceptibility testing. Molecular analyses of 16S ribosomal RNA gene sequences identified Citrobacter spp. and Morganella morganii. The patient was treated with ciprofloxacin and meloxicam and recovered after 2 months. This report describes the successful correction of a unilateral aural abscess that responded well to surgical intervention and a properly selected antibiotic.

• Journal of Veterinary Clinics
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• v.38 no.5
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• pp.225-230
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• 2021

A 4-year-old gelding Thoroughbred racehorse, which had been undergoing antibiotic therapy at a local veterinary clinic, was referred to the KRA veterinary center with a 20-day history of continuous right nasal discharge. Patient's history, endoscopic examination, and radiographic examination revealed primary maxillary sinusitis. Under sedation, surgical intervention was performed to collect samples and remove the accumulated mucopurulent exudate in the sinus. Swab samples were collected from the sinus during surgery for cytology and antimicrobial susceptibility testing. Only one type of bacteria was cultured, and molecular analyses of 16S ribosomal RNA gene sequences identified it as Staphylococcus aureus (S. aureus). The isolate was resistant to multiple antibiotics, which are frequently used in equine practice. Trimethoprim-sulfamethoxazole was chosen based on antibiotic susceptibility test, trephination, and sinus lavage using saline were applied to treat bacterial sinusitis. The clinical signs improved after 1 month and the patient resumed training. This report describes S. aureus isolated from bacterial maxillary sinusitis in a horse and its antibiotic susceptibility.

• Food Science and Preservation
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• v.30 no.5
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• pp.758-769
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• 2023

The main aim of this study was to determine python fat's several physicochemical properties, including dimensions, color, structure, acid value (AV), saponification value (SV), density, and recovery efficiency. The optimum yield obtained was approximately 80.40% at 180℃ for 60 min with an AV of 0.3366 and SV of 179.56 mg KOH/g. Fatty acids, comprising oleic acid (72.462%), palmitic acid (26.243%), linolenic acid (0.835%), and myristic acid (0.459%), were identified using gas chromatography-mass spectrometry (GC-MS). The python fat had a very weak antioxidant capacity and almost no antibacterial ability with gram-positive (Staphylococcus aureus - ATCC 25923 and Bacillus cereus - ATCC 10876) and gram-negative (Escherichia coli - ATCC 25922 and Salmonella enterica - ATCC 35664) bacteria (used the paper disc diffusion method for antibiotic susceptibility testing). Moreover, python fat is considered to be very resistant to high temperatures.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5219-5223
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• 2015

Helicobacter pylori (H. pylori) infection as a serious problem in both adults and children can induce chronic gastritis, peptic ulcer disease (PUD), and possibly gastric cancer. The aim of the current study was to survey antibiotic resistance and also to determine influence of PPAR$\gamma$ polymorphism in patients with H. pylori infection. During an 11-month-period, 98 H. pylori isolates were collected from 104 biopsy specimens. In vitro susceptibility of H. pylori isolates to 4 antimicrobial agents metronidazole, clarithromycin, amoxicillin and tetracycline were assessed by quantitative method according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guideline. PPAR$\gamma$ polymorphism was determined using polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of H. pylori infection in our study was 94.2%. In vitro susceptibility data showed that highest level of resistance was related to metronidazole (66.3%), and the majority of H. pylori isolates were highly susceptible to amoxicillin and tetracycline (94.9% and 96.9%, respectively). Genotypic frequencies were 25.5% for CC (Pro12Pro), 40.8% for GC (Pro12Ala) and 33.7% for GG (Ala12Ala). In our study, CG genotype had highest distributions among infected patients with H. pylori. The study suggests that the PPAR-$\gamma$ Pro12Ala polymorphism could be evaluated as a potential genetic marker for susceptibility to gastric cancer in the presence of H. pylori infection.