• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.171-180
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• 2022

The aim of this study was to investigate the prevalence of antimicrobial resistance and virulence factors in staphylococci isolated from canine otitis externa. A total 295 causative microorganisms were isolated. The most common isolated species were Staphylococcus (S) pseudintermedius (94 isolates) followed by Pseudomonas aeruginosa (60 isolates), S. schleiferi (25 isolates), Escherichia coli (23 isolates) and Proteus mirabilis (20 isolates). Staphylococci isolates were showed high resistance to penicillin (78.6%), erythromycin (55.9%), tetracycline (52.4%), clindamycin (51.7%) and ciprofloxacin (42.8%). Of the 145 staphylococci isolates, 49 (33.8%) methicillin-resistant staphylococci (MRS) were observed, distributed among S. pseudintermedius (n=34), S. schleiferi (n=6), S. epidermis (n=4), S. hominis (n=2), S. aureus, S. caprae and S. saprophyticus (n=1, respectively). Forty-three (87.8%) of 49 MRS and 10 (10.4%) of 96 methicillin-susceptibility staphylococci harbored mecA gene. About 80% of MRS were multidrug-resistant with resistance to at least one antibiotic in three or more antibiotic classes. Resistance genes blaZ (93/114, 81.5%), ermB (35/81, 43.2%), ermC (3/81, 3.7%), aacA-aphD (50/54, 92.5%), tetM (69/76, 90.7%) and tetK (6/76, 7.8%) were detected among resistant isolates. Virulence factors genes lukF and lukS were found in 100%(145/145) and 43.4%(63/145), respectively. Genes encoding ermA, eta, etb and tsst were not detected. To the best of our knowledge, this is the first study which investigated for the presence of genes encoding antimicrobial resistance and staphylococcal toxins in staphylococci isolated from canine otitis externa. A continuous monitoring and surveillance program to prevent antimicrobial resistance in companion animals is demanded.

• Biomedical Science Letters
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• v.25 no.1
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• pp.75-82
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• 2019

We developed the multiplex LAMP assay using 16S rRNA, femA and mecA genes for direct detection of the methicillin resistance in Staphylococci from positive blood culture. To simultaneously recognize Staphylococci genus, S. aureus and methicillin resistance, three sets of six primers for 16S rRNA, femA and mecA were designed, respectively. The performance of LAMP assay was affirmed using VITEK system for the phenotypic methods of identification and for oxacillin and cefoxitin antimicrobial susceptibility. The optimal condition for LAMP assay was obtained under $64^{\circ}C$ for 50 min. The detection limit was determined to be of 20 copies and CFU/reaction ($10^4CFU/mL$). For clinical application of comparison with phenotypic methods, the sensitivity and specificity of the LAMP with femA gene for detecting S. aureus was 95.31% and 100%, respectively. The sensitivity and specificity of the LAMP with mecA gene for detecting methicillin resistance was 98.46% and 100%, respectively. The multiplex LAMP assay with femA and mecA gene successfully detected all of MRSA (38 isolates) isolates from 103 Staphylococci in blood cultures. The LAMP assay developed in this study is sensitive, specific, and of excellent agreement with the phenotypic methods.

• Animal Bioscience
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• v.34 no.4
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• pp.734-742
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• 2021

Objective: The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential. Methods: A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex polymerase chain reaction-based assays using the specific primer sets. Results: A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%), and sen (28%), which were carried by 81% of S. saprophyticus. Conclusion: These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as staphylococcal cassette chromosome mec and tet(K).

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.251-255
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• 2019

Wildlife is a bio-indicator of environmental pollution by antimicrobial resistant bacteria or genes, however, there is no information on antimicrobial resistance in wildlife-origin bacteria. This study aimed to investigate the normal microbiota of staphylococci and their antimicrobial resistance in wildlife that did not take any antimicrobials. After sampling and bacterial isolation/identification, antimicrobial resistance profiles were examined by broth microdilution test, Kirby-Bauer disc diffusion test and mecA genetargeted PCR. Of 90 isolates from wildlife, 83 were coagulase-negative staphylococci while only 7 were coagulase-positive staphylococci. Methicillin-resistance was found in 63 (70%) isolates and 35 of 90 (38.9%) isolates were multidrug-resistant staphylococci. When considering that all of the animals did not take any medication or contacted any medical device before the sampling, the results indicate significantly high prevalence of antimicrobial resistance in wild environments. Further study would be necessary to investigate the transmission route of antimicrobial resistance.

• Journal of Life Science
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• v.26 no.2
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• pp.220-225
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• 2016

Coagulase-negative staphylococci (CNS) have recently become the bacteria most frequently found in clinical infections. The aim of this study was to investigate the prevalence, antimicrobial susceptibilities, and molecular characteristics of CNS isolates from dental clinic environments in Busan, Korea. One hundred and fifty-four samples were collected from 10 dental clinics and dental hospitals in Busan from December 2014 to January 2015. Species were identified by matrix-assisted laser desorption/ionization–time-of-flight. Antimicrobial susceptibility was determined by disk diffusion methods. A polymerase chain reaction was performed to detect mecA, mupA gene, and SCCmec types. Of the 154 samples, 10(6.5%) isolates were identified as CNS (5 Staphylococcus epidermidis, 2 Staphylococcus capitis, 2 Staphylococcus, and 1 Staphylococcus haemolyticus). Among the 10 isolates, 6 were resistant to penicillin, 5 were resistant to gentamicin, 3 were resistant to tetracycline, and 2 were resistant to cefoxitin and erythromycin. However, clindamycin, ciprofloxacin, teicoplanin, and trimethoprim-sulfamethoxazole resistant isolates were not present. Genes encoding mecA were detected in 4 (2 S. warneri and 2 S. haemolyticus) isolates, and mupA in 1 (S. epidermidis) isolate. One methicillin-resistant CNS (S. warneri) isolate was determined as being of the SCCmec type I. It is concluded that CNS resistant to various antimicrobial agents was widely distributed in dental clinic environments in Korea.

• 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.

• Food Science of Animal Resources
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• v.43 no.5
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• pp.792-804
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• 2023

Non-aureus staphylococci (NAS), particularly antimicrobial-resistant NAS, have a substantial impact on human and animal health. In the current study, we investigated (1) the species profiles of NAS isolates collected from healthy broilers, farm environments, and farm workers in Korea, (2) the occurrence of antimicrobial-resistant NAS isolates, especially methicillin resistance, and (3) the genetic factors involved in the methicillin and fluoroquinolone resistance. In total, 216 NAS isolates of 16 different species were collected from healthy broilers (n=178), broiler farm environments (n=18), and farm workers (n=20) of 20 different broiler farms. The two most dominant broiler-associated NAS species were Staphylococcus agnetis (23.6%) and Staphylococcus xylosus (22.9%). Six NAS isolates were mecA-positive carrying staphylococcal cassette chromosome mec (SCCmec) II (n=1), SCCmec IV (n=1), SCCmec V (n=2), or nontypeable SCCmec element (n=2). While two mecA-positive Staphylococcus epidermidis isolates from farm workers had SCCmec II and IV, a mecA-positive S. epidermidis isolate from broiler and a Staphylococcus haemolyticus isolate farm environment carried SCCmec V. The occurrence of multidrug resistance was observed in 48.1% (104/216 isolates) of NAS isolates with high resistance rates to β-lactams (>40%) and fusidic acid (59.7%). Fluoroquinolone resistance was confirmed in 59 NAS isolates (27.3%), and diverse mutations in the quinolone resistance determining regions of gyrA, gyrB, parC, and parE were identified. These findings suggest that NAS in broiler farms may have a potential role in the acquisition, amplification, and transmission of antimicrobial resistance.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.101-107
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• 2014

Community-acquired antimicrobial resistant bacteria are an emerging problem world-wide. In Korea, resistant bacteria are more prevalent than in other industrialized countries. The aim of this study was to investigate the isolation frequency of methicillin-resistant staphylococci (MRS), Pseudomonas, and Enterobacteriaceae from surrounding environment (home, colleges, public transportation system and possessions) in Seoul, and to examine the level of drug resistance to 13 antimicrobial agents, which are in wide spread clinical use in Korea, as well as new agent, tigecycline in Enterobacteriaceae isolates. Of total 239 samples, 18 (7.5%) MRS, 10 (4.2%) Pseudomonas, and 30 (12.6%) Entarobacteriaceae were isolated. A total of 5 (2.1%) methicillin-resistant S. aureus (MRSA) were detected in home (2 samples), colleges (1 sample), and et cetera (2 sample). A total of 5 (2.1%) Escherichia coli were detected in in home (1 samples), public transportations (3 sample), and et cetera (1 sample). Resistance to cephalosporins, fluoroquinolones, carbapenems, ${\beta}$-lactams, tetracyclines, and aminoglycosides was found in 71.9%, 71.9%, 68.8%, 68.8%, 50.0%, and 25.0% of 32 Enterobacteriaceae isolates, respectively. Also, resistance rate to trimethoprim/sulfamethoxazole of the isolates was a 43.8%. Moreover, 59.4% of the isolates were resistant to new agent, tigecycline and resistance to all agents tested was observed in 3 isolates. Five E. coli isolates were resistant to most of the agents tested, but some of them were susceptible to ciprofloxacin and gentamicin. This study can serve as a data point for future comparisons of possible changes in antibiotic resistance levels in surrounding environment. And multilateral strategies for preventing the incidence and spread of antibiotic resistance are needed.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.2
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• pp.86-91
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• 2010

We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.283-294
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• 1987

One hundred and fifty-seven strains of staphylococci isolated from various clinical specimens and 80 of Gram-negative bacilli from urine of patients with urological diseases were tested for resistance to antimicrobial drugs by microdilution broth method. Among staphylococci, 50 to 89% of the strains were resistant to gentamicin(Gm), kanamycin(Km), erythromycin(Em), nalidixic acid(Na), and tetracycline. Ninety per cent MIC was lowest in ciprofloxacin(Cp), followed by vancomycin(Vc), trimethoprim(Tp), enoxacin(Ex), and norfloxacin(Nf) with the values of two ${\mu}g/ml$ or lower. Twenty-seven strains were resistant to methicillin(MR), with 24 strains of Staphylococcus aureus and 3 of S. epidermidis. All strains of MR S. aureus were resistant to oxacillin, rifampin(Rf), Gm, Km, Em, Na, and Tc, and no strain was resistant to Vc and Tp. Almost all staphylococci isolated from urine were S. epidermidis and sensitive to most drugs tested without MR strain. Among Gram-negative bacilli from urine, Escherichia coli(43 strains) was most frequently isolated, and followed by Klebsiella spp.(11), Proteus spp.(10), Serratia spp.(10), and Pseudomonas aeruginosa(6) in the decreasing order. The majority of E. coli and Serratia spp. were resistant to chloramphenicol(Cm), Tc, streptomycin, sulfisomidine(Su), ampicillin(Ap), Km, and carbenicillin(Cb), and 50 and 90% MICs of these drugs were also high. In Klebsiella spp., 54% or more were resistant to Cm, Su, Ap, cephalothin, and Cb. Proteus spp. were susceptible to most drugs tested, but Pseudomonas were resistant to nearly all drugs tested except Rf, amikacin, and moxalactam(Mx). All Gram-negative bacilli tested were found to be susceptible to Mx. New quinolone carboxylic acid compounds, such as Nf, Ex, and Cp showed very high antimicrobial activities against the majority of organisms tested except Pseudomonas, and 50 and 90% MICs of Nf and Ex were always equal or 2 to 4 times higher than Cp. Organisms multiply resistant to drugs were noted in almost all isolates tested. Twenty-seven strains of staphylococci were multiply resistant to 11 or more drugs, and 6 of Klebsiella spp. to 8 to 11 drugs. The most frequent multiplicity of durg resistance were 7 and 8, 12, and 13 in E. coli, Serratia spp., and Pseudomonas, respectively. No strain was resistant to more than 5 drugs in Proteus spp..