• Korean Journal of Microbiology
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• v.48 no.2
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• pp.93-101
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• 2012

We analyzed mupirocin resistance rates among staphylococcal isolates collected from a Korean hospital in 2003 (100 isolates), 2005 (195 isolates), 2006 (151 isolates), and 2009 (112 isolates). In Staphylococcus aureus, rates of high-level mupirocin resistance (MIC, minimal inhibitory concentration ${\geq}512{\mu}g/ml$) decreased and did not appear since 2005. In contrast, low-level mupirocin resistance (MIC $8-256{\mu}g/ml$) was not detected in 2003 and 2005 but its rates later increased to 6.9% in 2009. Total resistance rates of coagulase-negative staphylococci (CNS) were significantly higher than those of S. aureus. The rates of high-level resistance of CNS increased from 16.0% in 2003 to 31.5% in 2009. The rate of low-level resistance of CNS was 8.0% in 2003 and around 11% later. In all high-level resistant isolates, the ileS-2 gene was detected. All low-level resistant isolates contained the known V588F mutation in ileS gene. Previously unknown mutations such as V458G in S. aureus and D172A, Y490H and I750V in CNS were identified additionally. One S. aureus isolate with high-level resistance was resistant to oxacillin and several topical antibiotics commonly used for the treatment of skin infection. Ten S. aureus isolates with low-level resistance were also resistant to all of these antibiotics except fusidic acid. CNS isolates with high-level (61 isolates) and low-level resistance (27 isolates) exhibited significantly higher resistance rates to these antibiotics than mupirocin-susceptible CNS isolates (167 isolates). In conclusion, prevention of the emergence of mupirocin resistance is necessary for the effective treatment of skin infection by staphylococci.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.127.1-127.1
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• 2003

The purpose of this study is to investigate the prevalence of resistance to macrolide, lincosamide, streptogramin and ketolide antibiotics in Korea. The antibiotic susceptibility test was performed to the macrolide erythromycin, clarithromycin, azithromycin, josamycin, the lincosamide clindamycin, the streptogramin synercid and the ketolide ABT -773 against 337 clinical Staphylococcus aureus(SAU). Coagulase-negative Staphylococci (CNS) and Enterococci isolates exhibited an average percentage of 64％, 56％, and 81 ％ of resistance to erythromycin, respectively.

• The Journal of the Korean Society for Microbiology
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• v.20 no.1
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• pp.13-23
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• 1985

This investigation was performed to isolate and identify Staphylococcus sp. from air at the 25 sites in one hospital in Daegu. Drug sensitivity tests bacteriologically were also studied. The results are summarized as follows: 1. In gram staining of isolated colonies, the number of staphylococci strains was 959(70.2%) among 1367 collected in the morning, and 653(66.2%) among 987 collected in the afternoon. 2. The number of isolates was slightly higher in samples collected from the outpatient treatment rooms and wards in the main building than in samples from the other sites. 3. In biochemical tests of 1612 strains of isolates gram positive cocci, the number of coagulase positive strains was 584(36.2%) and coagulase negative 1028(63.8%). In experiments on growth on mannitol agar containing 7.5% NaCl and mannitol fermentation tests, the number of mannitol fermentation strains was 423(30.8%) and nonfermenter was 951(59.2%). 4. In antibiotic sensitivity tests of 746 identified strains of staphylococci, coagulase positive strains showed resistance in. higher portions to penicillin(89.7%), chloramphenicol(64.6%), gentamycin (52.1%) and tetracycline(45.2%), whereas in lower portions to kanamycin(39.2%) and apmicillin(33.1%). 5. Among coagulase negative and mannitol fermenting strains, higher portions showed resistance to chloramphenicol(76.5%), penicillin(69.8%) and ampicillin(63.6%), whereas lower portions showed resistance to kanamycin(48.8%), tetracycline(39.5%) and gentamycin(34.0%). 6. The number of strains showing multiple resistance to above 6 antibiotics were 15(52(19.8%) among coagulase positive and mannitol non-fermenter and 36(22.2%) among coagulase negative and mannitol fermenter.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.615-621
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• 2020

Laccases are multicopper oxidases with important industrial value. In the study, a novel laccase gene (mco) in a Staphylococcus haemolyticus isolate is identified and heterologously expressed in Escherichia coli. Mco shares less than 40% of amino acid sequence identities with the other characterized laccases, exhibiting the maximal activity at pH 4.0 and 60℃ with 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) as a substrate. Additionally, the Mco is tolerant to a wide range of pH, heavy metal ions and many organic solvents, and it has a high decolorization capability toward textile dyes in the absence of redox mediators. The characteristics of the Mco make this laccase potentially useful for industrial applications such as textile finishing. Based on BLASTN results, mco is found to be widely distributed in both the bacterial genome and bacterial plasmids. Its potential role in oxidative defense ability of staphylococci may contribute to the bacterial colonization and survival.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.536-541
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• 2013

Background Pathogens in the nasal cavity during nasal surgery could lead to a systemic infectious condition, such as bacteremia, nosocomial infection, or toxic shock syndrome. However, there is no research about the prevalence of nasal carriage in patients with nasal bone fracture. Methods This was a prospective, double-blind, randomized study about the rate of nasal carriage in 200 patients with nasal bone fracture in Korea. Nasal secretions were taken from both the middle nasal meatus and colonized. All analyses were carried out using SPSS software. Results Pathogens were identified in 178 of the 200 cases. Coagulase-negative staphylococci (CNS) were the most cultured bacteria in 127 (66.84%) of the 190 total patients after excluding 10 cases of contaminated samples, and methicillin-resistant coagulase-negative staphylococci (MRCNS) were found in 48 (25.26%). Staphylococcus aureus was the second most identified pathogen, found in 36 (18.95%), followed by 7 cases (3.68%) of methicillin-resistant Staphylococcus aureus (MRSA). The prevalence rate of MRSA in the females was higher than that in the males (RR=4.70; 95% CI, 1.09-20.18), but other demographic factors had no effect on the prevalence rate of MRSA and MRCNS. Conclusions The prevalence rate of these pathogens in patients with nasal bone fracture in Korea was similar to other reports. However, few studies have addressed the prevalence rate of CNS and MRCNS in accordance with risk factors or the change in prevalence according to specific prophylaxis against infectious complications. Additional research is needed on the potential connections between clinical factors and microbiological data.

• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.531-537
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• 1993

A study was carried out to define the relationship between the N-acetyl-$\beta$-D-glucosaminidase(NAGase) levels and isolated pathogenic bacteria in 379 quarter fore milk of mastitis suspected samples collected in this clinics. All samples were tested the NAGase, California mastitis test(CMT), Somatic cell count(SCC) and bacterial culture. Except 111 from 379 samples, 268 bacteria-positive quarter fore milk samples were classified into the latent and mastitis infection group by SCC($500,000cells\;per\;m{\ell}$), and the mean NAGase levels($nmol/min/m{\ell}$) of each isolated pathogen in mastitis infection group were Staphylococcus aureus 3.067, Coagulase-negative staphylococci 4.083, Staphylococcus aureus 3.594, Str. uberis 3.513, Str. dysgalactiae 1.640, E coli 4.441 and gram negative rods 4.560, respectively. Most of the relationship between mean SCC and NAGase in each pathogen group were highly significant using a student t test(p<0.05). When the mastitis pathogens were classified into minor(Coagulase-negative staphylococci, Corynebacterium sp.) and major pathogen group(Staphylococcus aureus, Streptococcus agalactiae, Str. uberis, Str. dysgalactiae, gram negative rods), the NAGase levels were higher at major than minor pathogen group. On the other hand, when the mastitis milk samples were classified by SCC($500,000cells\;per\;m{\ell}$) and by the presence of pathogen(IDF scheme), the NAGase levels were also higher at the mastitis than latent infection. The possibility of combining SCC and NAGase data in order to give the more difinitive diagnosis is discussed.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.275-282
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• 1987

Strains of bacteria resistant to beta-lactam antibiotics have been increasing in number and are becoming troublesome in clinical medicine. The in vitro antibacterial activity of augmentin, a combination drug consisting of two parts amoxycillin to one part clavulanic acid, a potent beta-lactamase inhibitor, and their minimum inhibitory concentrations were determined by an agar dilution technique against ampicillin-resistant clinical isolates in Korea. Of the 226 strains tested, 140 strains(62%) were resistant to ampicillin. Among the 140 ampicillin-resistant strains, all Salmonella spp. Proteus spp. the majority of S. aureus and Shigella spp. were sensitive to augmentin. Ps. aeruginosa remained 100% resistant and there has been a considerable decline in resistant strains in E. coli and K. pneumoniae although a significant percentage of strains showed intermediate sensitivity. The minimum inhibitory concentrations of augmentin were ranged in $8{\mu}g/ml$ to $32{\mu}g/ml$ in most bacteria and all S. aureus were inhibited by $8{\mu}g/ml$. In our microbiological studies we have shown that augmentin is active against ampicillin-resistant strains of Staphylococci and Gram-negative bacteria. In this hospital there would appear to be a significant number of strains of E. coli and K. pneumoniae showing intermediate resistance to augmentin. Most of these strains should be susceptible to augmentin given by mouth or by the intravenous route depending on the concentrations of both amoxycillin and clavulanic acid obtainable in the various tissues.

• Food Science of Animal Resources
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• v.44 no.2
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• pp.372-389
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• 2024

This study investigated the efficacy of ultraviolet-C (UV-C) irradiation in enhancing the quality of raw bovine milk by targeting microbial populations and lipid peroxidation, both of which are key factors in milk spoilage. We categorized the raw milk samples into three groups based on initial bacterial load: low (<3 Log 10 CFU/mL), medium (3-4 Log 10 CFU/mL), and high (>4 Log 10 CFU/mL). Using a 144 W thin-film UV-C reactor, we treated the milk with a flow rate of 3 L/min. We measured the bacterial count including standard plate count, coliform count, coagulase-negative staphylococci count, and lactic acid bacteria count and lipid peroxidation (via thiobarbituric acid reactive substances assay) pre- and post-treatment. Our results show that UV-C treatment significantly reduced bacterial counts, with the most notable reductions observed in high and medium initial load samples (>4 and 3-4 Log 10 CFU/mL, respectively). The treatment was particularly effective against coliforms, showing higher reduction efficiency compared to coagulase-negative staphylococci and lactic acid bacteria. Notably, lipid peroxidation in UV-C treated milk was significantly lower than in pasteurized or untreated milk, even after 72 hours. These findings demonstrate the potential of UV-C irradiation as a pre-treatment method for raw milk, offering substantial reduction in microbial content and prevention of lipid peroxidation, thereby enhancing milk quality.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.407-412
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• 2017

The aim of this study was to shorten the time required for subculture and bacterial identification and obtain a simple and rapid identification method for new test methods for bloodstream infections. The following results were obtained using a mass spectrometer. In Vitek 2, 208 (81.8%) cases were well-identified and 45 isolates were not identified in blood cultures. Among 208 cases, 146 (57.5%) were Gram positive bacteria and 108 (42.5%) were Gram negative bacteria. In total, 233 were identified to the species level and 21 were identified to the genus level. The identification error was found to be Propionibacterium acnes as Clostridium bifermentans. The accuracy of Enterobacteriaceae, glucose non-fermentative bacilli (GNFB), and staphylococci were 81/83 (97.6%), 12/15 (80.0%), and 72/85 (84.7%), respectively. The concordance rate of Vitek 2 and Vitek MS by the direct method was 81.8% and 45 isolates were not identified. Most of the unidentified bacteria were Gram positive bacteria (N=37). The Gram positive bacteria were streptococci (14), coagulase-negative staphylococci (CNS) (11), enterococci (3), Staphylococcus aureus (2), Micrococcus spp. (2), Bacillus spp. (2) and Actinomyces odontolyticus, Finegoldia magna, and Peptostreptococcus spp. The results reporting time was reduced to 24~72 hours compared to the conventional method. The rate of identification of the aerobic and anaerobic cultures was similar, but the use of an anaerobic culture did not require a dissolution process, which could shorten the sample preparation time. These results suggest that the method of direct identification in blood cultures is very useful for the treatment of patients. In further studies, it might be necessary to further improve the method for identifying streptococci and CNS, which were lacking in accuracy in this study.

• Korean Journal of Veterinary Service
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• v.20 no.1
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• pp.37-45
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• 1997

The result of API staph-ident system was compared with cellular fatty acid composition for the identification of Staphylococcus species isolated from cattle. Isolated strains from cattle were correctly identified to S aureus, S intermedius, S hyicus, S simulans, S saprophyticus, S epidemis, S sciuri and S xylosus by API staph-ident system. The correlation between bacterial cellular fatty acid profile and Staphylococcus species isolated to API STAPH-IDENT system were. In conclusion, the result presented indicate that Staphylococci can be indentified to the species level by the cellular fatty acid profiles. Moreover, computerized fatty acid profile correlative anaylsis can be applied for determining identify of Staphylococcus species.