• Korean Journal of Microbiology
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• v.38 no.4
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• pp.306-311
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• 2002

PCR of the mecA gene for the rapid detection of methicillin-resistant staphylococci was perfomed and compared with the antibiotic sensitivity test. A total of 43 strains of staphylococi from clinical specimens were used in this study. An antibiotic sensitivity test by the agar dilution method of NCCLS (The National Commitee for Clinical Laboratory Standard) was performed for the strains. Among them, 39 isolates were methicillin-resistant (MRS), and 4 isolates were methicillin-susceptible (MSS). With the exception for one strain (Staphylococcus cohnii, HRC2-4), all MRS strains amplified the expected 533 bp fragments of the mecA gene by PCR, However, one strain (Staphylococcus aureus, HSA1-10) that was classified as a sensitive strain by the antibiotic sensitivity test was mecA positive by PCR. All 35 methicillin-resistant Staphylococcus aureus (MRSA) strains were mecA positive, but overall, concordance between the results of the mecA PCR and antibiotic sensitivity test was 95.6%.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.147-153
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• 2017

The purpose of this study was to isolate Escherichia coli from flies and to assess pathogenic genes and antibiotic resistance of the isolates. A total of 188 flies were captured in agricultural environment including fruits farms (n = 19), fermented soybean farms (n = 9), municipal waste (n = 46), livestock farms (n = 66), slaughterhouses (n = 38), and manure ground (n = 10). E. coli isolates of captured flies were tested for pathogenic gene and antibiotic resistance using PCR methods and VITEK2 systems. As a result, E. coli from 63% (119/188) of the captured flies has been detected, and the detection rate of E. coli was the highest (89%, 31/34) in flies captured at particular slaughterhouse. Of the 34 isolates, 94% (32/34) were pathogenic gene (ST gene) positive. Twenty-six percent (31/119) of the E. coli isolates were observed being resistant to one or more antibiotics. Markedly, one of E. coli isolates from Livestock farms was resistant to 7 antibiotics including ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, gentamicin, levofloxacin, and trimethoprim/sulfamethoxazole. In addition, it was ESBL positive. The results of the present study may suggest a risk of transmission of pathogenic and antimicrobial resistant bacteria from flies to livestock environment Therefore, it may need to prevent introducing flies into the agricultural production environment for safe food production.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.67-73
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• 2010

Purpose : We aimed to compare the clinical features and antibiotic resistance of urinary tract infection (UTI) caused by pathogens other than E. coli (non-E. coli) with UTI caused by E. coli in children. Methods : We enrolled patients with culture-proven UTI, who were admitted to the study hospital from September 2008 to August 2009. We investigated clinical data of patients with UTI and antibiotic resistance of isolated strains. For comparison, patients were divided according by results of the urine culture into E. coli and non-E. coli UTI groups. Results : A total of 84 patients participated in this study. Twenty one cases (25.0%) were caused by non-E. coli pathogens. Frequency of non-E. coli UTI differed according to age and sex: 'male <6 months', 10.5%; 'male ${\geq}$6 months', 50.0%; 'female <6 months', 43.7%; and 'female ${\geq}$6 months', 25.0% (P=0.014). More patients who received previous antibiotic treatment (P=0.017), but fewer patients who showed hematuria (P=0.014) were included in the non-E. coli UTI group than in the E. coli UTI group. Comparison of antibiotic resistance showed that the non-E. coli UTI group possessed more strains that were resistant to cefazolin, cefotaxime, imipenem, trimethoprim/sulfamethoxazole (TMP/SMZ) and tetracycline than the E. coli UTI group (P<0.05). Conclusion : Increased incidence, different distribution by age and sex, and high antibiotic resistance of non-E. coli UTI should be considered in selection of empirical antibiotics for treatment of UTI in children.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.135-140
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• 2017

The aim of this study was to investigate the distribution of genes that encode multi-drug efflux pumps and virulence factors in Enterococcus faecalis isolated from retail meat and antibiotic resistance patterns of these strains. Of the 277 retail meat samples, 93 Enterococcus faecalis were isolated. The strains exhibited resistance to ampicillin (35.5%), chloramphenicol (6.4%), ciprofloxacin (4.3%), erythromycin (18.3%), levofloxacin (0%), quinupristin-dalfopristin (76.3%), tetracycline (45.2%), teicoplanin (0%) and vancomycin (0%). The strains were positive for MFS type eme(A) (100%), ABC type efr(A) (100%), ABC type efr(B) (98.9%) and ABC type lsa (91.4%) efflux pump gene. The strains were positive for gelE (68.8%), ace (90.3%), asa1 (47.3%), efaA (91.4%) and esp (12.9%) virulence gene. This research will help to assess the hazards associated with the occurrence of drug resistance among enterococci from retail meat. Therefore, it is necessary to monitor enterococcus spp. isolated from retail meat continuously.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.240-246
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• 2008

From the 4 sampling stations located in the basin of the Han River, total 46 strains of Enterococcus spp. composed of 15 E. faecium strains, 26 E. casseliflavus strains, 1 E. faecalis strain and 4 E. hirae strains were isolated. Among the 46 strains, 45 strains exhibited streptomycin-resistance, while 21 and 19 stains were resistant against tetracycline and quinupristin/dalfopristin, respectively. As for gentamicin and vancomycin, 15 strains and 1 strain showed resistance against the respective antimicrobial agents. Among the 46 strains, 39 strains showed resistance against more than 2 antimicrobial agents, and 10 strains demonstrated resistance to more than 5 antimicrobial agents. Especially, the strain isolated from the station C at Anyangcheon, exhibited resistance against all the 8 kinds of the antimicrobial agents. As the sampling site approached to the lower stream of the Han-river, the antibiotic resistant strains and the multi-drug resistant strains were detected more frequently. The MIC values of the antibiotic resistant strains measured by the disc diffusion method disclosed that 16 strains possessed maximum MIC value of 4,096 ${\mu}g$ mL$^{-1}$ against streptomycin and 17 strains possessed maximum MIC value of 2,048 ${\mu}g$ mL$^{-1}$ against gentamicin. Meanwhile, 1 strain exhibited maximum MIC value of 5121 ${\mu}g$ mL$^{-1}$ against vancomycin. As for quinupristin/dalfopristin and tetracycline, 2 and 33 strains showed maximum MIC value of 641 ${\mu}g$ mL$^{-1}$, respectively. Comparison of the MIC values of the strains of the this study with those of the strains of the other research groups isolated from the hospital drainage and also those from the live stock farm drainage indicated that the strains resistant against vancomycin and quinupristin/dalfopristin may be originated from the livestock farm drainage.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.413-419
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• 2017

Four imipenem-resistant bacteria were isolated from the clinical specimens of a patient with pneumonia. To identify the isolates, we used the GN card of Vitek II system and performed a phylogenetic analysis based on 16S rRNA gene sequence. The isolates were identified as P. aeruginosa (2 strains), P. monteilii (1 strain), and P. putida (1 strain), and were tested for antibiotic resistance after determining the MIC of imipenem to be $${\geq_-}8{\mu}g/mL$$ using the AST-N225 card of Vitek II system. The imipenem-resistant genotypes were determined using PCR products amplified using specific ${\beta}-Lactamase$ gene primers. The MBL gene was identified in all four isolates. One strain of P. aeruginosa exhibited the VIM and SHV-1 type genes, while the other strain exhibited both VIM and OXA group II genes. According to the antimicrobial susceptibility test, the bacteria were more susceptible to amikacin than other antibiotics. DNA fingerprint analysis using ERIC-PCR to analyze the epidemiological relationship between strains estimated that both the P. aeruginosa isolates were similar, but exhibited different DNA band types. It is uncommon to find four strains of imipenem-resistant bacteria with different DNA band types in a single patient.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.45-51
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• 2007

The Collected 70 samples from 5 sandwich shops were analysed for the pathogenic bacteria such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus. As a result of Listeria monocytogenes and Saphylococcus aureus were detected in 1 sample, 11 samples, respectively. However, Escherichia coli O157:H7 and Salmonella spp. were not detected in anywhere. The antibiotics test of isolated bacteria was pelformed by the disk diffusion method from NCCLS. The resistance rate of Listeria monocytogenes isolates was confirmed 38.5% to 10 species such as Am, B, P, and Va for antibiotics of 26 species. MRSA was determinated 4 strains in S. aureus isolates. The resistance pattern of Staphylococcus aureus isolates were confirmed 36.4% to P Am OX B K E CXM, 18.2% to P Am B K E CXM B, 9.1% to P Am B K, 27.3% to P Am B, and 9.1% to Te B Nb. Therefore, continuous surveillance and monitoring for antibiotic resistance strains are demanded for prevention of increases in multiple antibiotic resistance strains.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.252-256
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• 2006

We monitored antibiotic resistance of Escherichia coli isolates from healthy volunteers of community and hospital patients from February to July in 2006. From disc diffusion test on 4915 E. coli isolates from healthy volunteers of the community, the resistance rates were as follows; tetracycline resistant, 46.6%; ampicillin resistant, 41.1%; ticarcillin resistant,37.9%. From disc diffusion test on 120 E. coli isolates from hospital patients, the resistance rates were as follows: ampicillin resistant, 66.9%; ticarcillin resistant, 63.8%; tetracycline resistant, 47.2%. Extended spectrum $\beta$-lactamase producing E. coli were isolated 0.6% and 4.1% from healthy volunteers and hospital patients.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.149-154
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• 2005

Fifty-one extended-spectrum-${\beta}$-lactamase(ESBL) producing Klebsiella pneumoniae strains were isolated from national university hospitals. All K. pneumoniae strains showed resistance to broad-spectrum antibiotic and most of them presented resistance to amikacin, gentamicin and ciprofloxacin. The results of amplified polymorphic DNA (RAPD) pattern for randomly isolated fifty-one strains were as follows; both twenty-one strains from Chungnam National University hospital and ten strains from Chungbuk National University hospital showed RAPD type Ia and Ib. However, twenty strains isolated from Gyeongsang National University hospital belonged to RAPD type IIa and IIb. All isolates were divided into four molecular types and showed high level of genetic diversity. These results suggested that RAPD analysis provided a rapid and simple method for analysing genotypes of ESBL.

• The Journal of the Korean Society for Microbiology
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• v.13 no.1
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• pp.7-16
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• 1978

One hundred and three clinical isolates of enterococci were examined for susceptibility to 8 antibiotics, and transferability and transfer frequency of R plasmid. Ampicillin was the most active, followed in decreasing order by rifampin, amikacin and chloramphenicol, and tetracycline. High-level resistance(${\geq}2,000{\mu}g/ml$) to kanamycin, streptomycin, and gentamicin, known as the most active of the aminoglycosides to enterococcus, was present in 26.2%, 21.4%, and 18.3% of the isolates, respectively. In the drug susceptibility of the species, S. zymogenes was the most resistant and S. durans was the most sensitive to tested antibiotics. We could observed the transferability of enterococcal R plasmid in mixed culture: among the 28 strains which showed multiple drug resistance, 17 strains transferred all or part of their resistance with $2{\times}10^{-4}-2{\times}10^{-6}%$ of transfer frequency to a plasmid-free recipient, S. faecalis strain JH 2-2.