• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.916-924
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• 2017

Eighty-five Enterococcus faecalis isolates collected from animals (40 isolates), meju (a Korean fermented soybean product; 27 isolates), humans (10 isolates), and various environmental samples (8 isolates) were subjected to multilocus sequence typing (MLST) to identify genetic differences between samples of different origins. MLST analysis resulted in 44 sequence types (STs), and the eBURST algorithm clustered the STs into 21 clonal complexes (CCs) and 17 singletons. The predominant STs, ST695 (21.1%, 18/85) and ST694 (9.4%, 8/85), were singletons, and only contained isolates originating from meju. None of the STs in the current study belonged to CC2 or CC9, which comprise clinical isolates with high levels of antibiotic resistance. The E. faecalis isolates showed the highest rates of resistance to tetracycline (32.9%), followed by erythromycin (9.4%) and vancomycin (2.4%). All isolates from meju were sensitive to these three antibiotics. Hence, MLST uncovered genetic diversity within E. faecalis, and clustering of the STs using eBURST revealed a correlation between the genotypes and origins of the isolates.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.1
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• pp.1-4
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• 2013

Vancomycin-resistant enterococci (VRE) have emerged as important healthcare-associated infection since last two decades. ChromID VRE agar (cIDVA) is useful for VRE rectal swab screening. We investigated all VRE were isolated on the cIDVA. A total of 363 rectal swabs of 85 patients to test VRE screening were inoculated into bile-esculin (B-E) broth with $6{\mu}g/mL$ vancomycin. After 24 hours incubation, we subcultured B-E broths were changed to black onto cIDVA. All isolates were identified by the MICROSCAN and VITEK2. The vanA gene and vancomycin minimal inhibition concentration (MIC) were detected by PCR and E-test respectively. 277 E. faecium (84.7%), 16 E. faecalis (4.9%), 25 E. avium (7.6%), 8 E. gallinarum (2.4%) and 1 E. raffinosus (0.3%) were isolated. 10.3% of VRE detected on cIDVA were other than E. faecium and E. faecalis that presented various color from colorless to pale violet. All isolates contained vanA and vancomycin MIC were > $256{\mu}g/mL$. VRE isolates other than E. faecium and E. faecalis should be objective to the contact precautions for healthcare-associated infection control if they possess vanA gene. Due to emerging enterococci carrying vanA such as E. avium, E. gallinarum, and E. raffinosus, VRE surveillance should be expanded to all isolates on chromogenic agar.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.427-434
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• 2017

Species that belong to the Acinetobacter calcoaceticus-baumannii (Acb) complex are major causes of hospital-acquired infections. They are important opportunistic pathogens. These species are usually multidrug resistant (MDR), and the therapeutic options to treat the infections caused by these species are limited. In the present study, we investigated fluoroquinolone resistance mechanisms in 53 ciprofloxacin resistant Acinetobacter species isolates in Chungcheong, Korea. Antimicrobial susceptibilities were determined using the disk-diffusion method. Detections of genes and identification of mutations associated with fluoroquinolone resistance were carried out using PCR and DNA sequencing. In our study, 47 out of 53 ciprofloxacin resistant Acinetobacter isolates harbored sense mutations at the 83rd residue (serine to leucine) in the gyrA gene as well as at the 80th residue (serine to leucine) in the parC gene. Among the 47 isolates harboring sense mutations in gyrA and parC gene, 44 isolates were A. baumannii and 3 isolates were A. pittii. Plasmid-mediated quinolone resistance (PMQR) determinants were detected in isolates in our study. Among the 46 ciprofloxacin resistant A. baumannii isolates, 41 showed type A, B, or F banding patterns on their REP-PCR profiles. This result suggests that clonal relation and horizontal spreading of the bacterial isolates have been around hospitals in Chungcheong area. To prevent colonization and disseminations of fluoroquinolone resistance Acb complex isolates, continuous investigation and monitoring of antimicrobial resistant determinants of MDR isolates are needed.

• Korean Journal of Veterinary Research
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• v.22 no.2
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• pp.121-138
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• 1982

The present study was conducted in order to investigate the role of yeast-like fungi in bovine mastitis. Attempts were made to isolate and identify yeast-like fungi from the milk from normal udders and those with clinical or subclinical mastitis and from feces. Also incuded in the study were trials for the pathogenicity of the isolates for laboratory animals and efficacy of an anti-fungal drug for the treatment of mastitis. A total of 133 isolates of yeast-like fungi was made from milk and feces and they were identified as Candida (C.) albicans (5 isolates), C. krusei (63 isolates), C. tropicalis (27 isolates), Torulopsis (T.) glabrata (10 isolates), Rhodotourla sp. (6 isolates), Hansenula sp. (6 isolates) and Pichia sp. (1 isolate). Sixty seven strains of yeast-like fungi were isolated from the milk of 64 quarters (4.3% of quarters examined) of 55 cows (14.3% of cows examined). C. krusei, C. tropicalis, C. pseudotropicalis, C. parapsilosis and T. glabrata were isolated as the causative agents from 20 quarters (1.3% of quarters examined) with clinical mastitis. C. krusei, C. tropicalis, C. albicans, C. pseudotropicalis, T. glabrata, Rhodotorula sp. and Hansenula sp. were isolated as the causative agents from 22 quarters (1.5% quarters examined) with subclinical mastitis. C. tropicalis, C. krusei, T. glabrata and Rhodotorula sp. were isolated as the contaminants from 22 normal quarters (1.5% of quarters examined). C. krusei, C albicans, C. tropicalis, C. pseudotropicalis, C. parapsilosis, T. glabrata, Hansenula sp., Rhodotorula sp. and Pichia sp. were isolated as the contaminants from feces and all of the species except Pichia sp. were isolated from milk of the same cows at the some time. Intramammary infusion of nystatin was effective for the treatment of mastitis caused by C. albicans, C. krusei, C. tropicalis, C. pseudotoropicalis, C. parapsilosis, T. glabrata and Rhodotorula sp. C. albicans, C. krusei, C. tropicalis, C. pseudotropicalis, T. glabrata, Hamsenula sp. and Pichia sp. were pathogenic for rat but C. parapsilosis and Rhodotorula sp. were not.

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.239-248
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• 2021

The emergence of multidrug-resistant Acinetobacter baumannii has partly increased treatment failure and patient mortality. Class D β-lactamases is an important mechanism of resistance to beta-lactam antibiotics in this species. This study aimed to investigate the relationship between the presence oxacillinase gene and genetic fingerprints of A. baumannii isolates from the intensive care unit of an Egyptian tertiary care hospital. One hundred and twenty A. baumannii clinical isolates were collected. Multiplex PCR was performed to detect genes encoding oxacillinases (OXA-23, OXA-24, OXA-51, OXA-58 and OXA-143). Molecular typing of all collected isolates was performed using random amplified polymorphic DNA (RAPD)-PCR assay. Out of 120 examined isolates, 92, 88 and 84% were resistant to ertapenem, imipenem and meropenem, respectively. The species-specific, commonly present OXA-51 gene was found in all isolates while OXA-23 showed a high prevalence of 88% of isolates. OXA-24 and OXA-143 genes were detected in 3% and 1% of isolates, respectively. No OXA-58 gene was detected. Five clusters consisting of 19 genotypes were detected using RAPD-PCR. Genotype A was the most prevalent, it was observed in 62% of the isolates followed by genotype B (12%). These results revealed that genotypes A and B are common in the hospital. Results also demonstrate that RAPD-PCR is a rapid and reliable method for studying the clonal similarity among A. baumannii isolated from different clinical specimens.

• Mycobiology
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• v.42 no.1
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• pp.73-78
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• 2014

Cryptococcal infection is primarily caused by two species, Cryptococcus neoformans and C. gattii. Between the two species, C. neoformans var. grubii is the major causative agent of cryptococcosis in Asia. We investigated the molecular characteristics of 46 isolates of C. neoformans from patients with cryptococcosis between 2008 and 2012 in Seoul, Korea. All the isolates were determined to be C. neoformans var. grubii (serotype A), mating type $MAT{\alpha}$, and molecular type VNI by PCR-restriction fragment length polymorphism of the URA5 gene. Multilocus sequencing type (MLST) analysis using the International Society of Human and Animal Mycoses (ISHAM) consensus MLST scheme identified two sequence types (ST). Out of the 46 strains, 44 (95.7%) were identified as ST5, and remaining 2 were identified as ST31. Our study revealed that the clinical strains of C. neoformans in Korea are genetically homogeneous with the VNI/ST5 genotypes, and new appearance of VNI/ST31 genotype may serve as an important indicator of global genetic analysis.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.679-693
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• 1995

The present study has been performed to see the intrafamilial transmission of periodontopathic organism Actinobacillus actinomycetemcomitans in Koreans having various froms of periodontal diseases. 17 clinical isolates from 8 periodontal patients and 20m clinical isolates from their 8 family members were grown anaerobically for the serotyping and the extraction of genomic DNA. The DNA was digested with restriction endonucleases (EcoRI+HindIII) and plasmid pAA 2097(kindly provided by Dr. DiRienzo, Univ. of Pennsylvania) including 4.7kb-size randlomly clone probe for restriction length pleomorphism analysis(RFLP). RFLP patterns of reference serotypes a, b, c, d, and e were used as the genotypes A, B, C, D, and E, respectively for comparison of genotypes of clinical isolates. 28 out of total 37 clinical isoltes belonged to either one of 5 basic gentotypes and 9 remaining isolats did not fall into any types, and hence were designate as non-type(NT). Genotype C were the most frequently found one(35.1%) and genotype B has not isolated. Intrafamilial transmission of bacteria between spouses, brothers and sisters, and parents and their offsprings, resepctively could well be demonstrated by comparing RFLP patterns. There were not any specific genotypes which showed predominance over others in terms of transmission.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.1012-1014
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• 2013

DNA-DNA hybridization method with four oligonucleotide-specific probes was used simultaneously for differentiation and identification of four Mycobacterium species (Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii). This DNA-DNA hybridization method with 4 oligonucleotide-specific probes, which targets in the rpoB region of 4 Mycobacteria species, respectively, was tested on 322 clinical isolates. Using DNA-DNA hybridization method, we detected M. tuberculosis (282 strains), M. avim (7 strains), M. intracellulare (9 strains), and M. kansasii (3 strain) from 322 clinical isolates. This result was compared with conventional biochemical test and rpoB DNA sequence analysis of this clinical isolates. We confirmed identification of Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii with high sensitivity (100 %) and specificity (100 %). This DNA-DNA hybridization method could be performed within 4 hours at least. Therefore, we suggest that DNA- DNA hybridization method using 4 rpoB DNA probes of Mycobacteria could be used for accurate, rapid, convenient detection and identification of Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii in clinical samples.

• Biomedical Science Letters
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• v.19 no.3
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• pp.213-223
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• 2013

The objectives of this study are to develop a molecular diagnosis to differentiate serotypes and mating-types of C. neoformans/C. gattii complex isolates from pigeon droppings in Korea and to elucidate molecular epidemiology of the isolates. Phenotypes and genotypes of C. neoformans/C. gattii complex isolates were identified by biochemical properties and PCR using specific CNLAC1 gene, respectively. To classify serotypes and mating-types of C. neoformans/C. gattii complex isolates, the five reference strains and thirty-three isolates in Korea were investigated by restriction fragment length polymorphism (RFLP) analysis using CNLAC1 gene for varieties, by random amplified polymorphic DNA (RAPD) for serotyping, and by PCR using specific primer sets for mating typing. All isolates in Korea were belonged to C. neoformans var. grubii (serotype A) by RFLP and RAPD patterns which showed high sensitivity and specificity. Therefore, RFLP and RFLP were available to differentiate varieties and serotypes of C. neoformans. Amplification patterns of the five reference strains by specific PCR for mating typing were differentiable, and all isolates were classified into $MAT{\alpha}$. All C. neoformans environmental isolates in Korea were Cr. neoformans serotype A and $MAT{\alpha}$ which is a more virulent pathogen. This study suggests that RFLP and RAPD are rapid and correct molecular diagnosis tools for epidemiology of C. neoformans/C. gattii complex isolates.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.94-101
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• 2016

Acinetobacter species isolates are important opportunistic pathogens and commonly implicated in nosocomial infections. The therapeutic options for treatment of the bacterial infections are limited because the bacteria isolates are usually multidrug resistant (MDR). In the current study, we investigated various carbapenemase genes in 68 Acinetobacter species isolates. Antimicrobial susceptibilities were tested using the disk diffusion method. Screening of carbapenemase genes was performed via multiplex PCR. In addition, PCR and DNA sequencing were used to identify the carbapenemase genes. Repetitive extragenic palindromic-PCR (REP-PCR) was also performed to assess the clonality of isolates. In our study, A. baumannii isolates were highly resistant to all agents tested while all non-A. baumannii isolates were susceptible to all agents tested, with the exception of aztreonam and cefotaxime. All 51 A. baumannii isolates contained the $bla_{OXA-51}$ gene and 37 (72.5%) isolates also harbored the $bla_{OXA-23}$ gene. In addition, 39 MDR A. baumannii isolates were identified in our study and 37 isolates contained the $bla_{OXA-23}$ gene. The 37 MDR strains harboring $bla_{OXA-23}$ showed type I (n=22) or type II (n=15) banding patterns on their REP-PCR profiles. Our results suggest clonal relation and horizontal spreading of MDR A. baumannii isolates containing the $bla_{OXA-23}$ gene at the hospital located in Daejeon. Continuous investigation of antimicrobial resistant determinants and monitoring emergence and dissemination of MDR isolates is required to prevent and control infection and colonization of MDR A. baumannii isolates.