• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.180-184
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• 2001

MRSI is the staphylococcal infection having resistance to the methicillin which is semisynthetic penicillinase-resistant agents against penicillinase. These infections are very difficult to treat because they have resistance to almost every antibiotics except for vancomycin. We experienced MRSE(methicilline-resistant staphylococcal epidermis) infected 56 years old man who developed 2 months after arthroplasty for TMJ ankylosis and MRSA(methicilline-resistant staphylococcal aureus) infected 59 years old man who was performed arthroplasty far traumatic TMJ disc displacement.

• Biomedical Science Letters
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• v.27 no.4
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• pp.195-207
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• 2021

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen capable of causing human diseases, such as soft tissue infection, bacteremia, endocarditis, toxic shock syndrome, pneumonia, and sepsis. Although the incidence rate of diseases caused by MRSA has declined in recent years, these diseases still pose a clinical threat due to their consistently high morbidity and mortality rates. However, the role of virulence factors in staphylococcal infections remains incompletely understood. Methicillin resistance, which confers resistance to all β-lactam antibiotics in cellular islets, is mediated by the mecA gene in the staphylococcal cassette chromosome mec (SCCmec). Differences in SCCmec types and differences in their sizes and structures serve epidemiological purposes and are used to differentiate between hospital-associated (HA)-MRSA and community-associated (CA)-MRSA. Some virulence factors of S. aureus are also providing a distinction between HA-MRSA and CA-MRSA. These factors vary depending on the presence of toxins, adhesion, immune evasion, and other virulence determinants. In this review, we summarized an overview of MRSA such as resistance mechanisms, SCCmec types, HA- and CA-MRSA, and virulence factors that enhance pathogenicity or MRSA epidemiology, transmission, and genetic diversity.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.205-209
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• 2009

Staphylococcal toxic shock syndrome (TSS) is a severe systemic illness caused by toxins produced by Staphylococcus aureus. We report a case of staphylococcal TSS in a 16 month-old boy who presented with high fever, vomiting, skin rash, and shock after a burn injury. He was managed with intravenous vancomycin, fresh frozen plasma, and intravenous immunoglobulin. Methicillin-resistant S. aureus (MRSA) was isolated from the burn wound site and anterior nostril of the patient. In addition, the MRSA isolate was genetically characterized.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.276-282
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• 1998

Staphylococcal pneumonia caused by staphylococcus aureus can be characterized by its severity and rapid progress as a bacterial infection. The disease shows a high mortality in younger patients, especially in infants unless early and appropriate treatment is carried out. Treatment can be made of medical method alone but in cases of surgical interventions are needed, immediate surgical methods such as closed or open drainage of pleural fluid, lobectomy and decortication should be followed with combination of medical therapy. The choice of antibiotic should be made by proper antibiotic sensitivities tests. For a methicillin sensitive S. areus(MSSA), the penicillase resistant penicillin would be the first choice and for a methicillin resistant S. aureus (MRSA), the glycopeptides such as vancomycin would be the first one. Other drugs can also be used if the bacterial agents show any sensitivities to these drugs. Commonly, the chest roentgenographic findings reveal infiltrations, empyema, pneumothorax, pleural effusion, atelectasis or pneumatoceles in staphylococcal pneumonia and this fact easily can lead the physicians to its diagnosis as soon as possible. We experienced 5 cases of staphylococcal pneumonia in infants, proven by through bacterial cultures and report them with brief review of the related literatures.

• Journal of Food Hygiene and Safety
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• v.29 no.3
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• pp.223-227
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• 2014

This study was investigated to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) isolated from raw milk samples and to further study on the molecular characteristics of the MRSA isolates. Using Staphylococcus Medium 110, Staphylococcus spp. were isolated from raw milk samples and further identification was carried by Vitek2 system. Minimum inhibitory concentrations (MICs) of antibiotics were conducted by serial dilution method according to the Clinical Laboratory Standards Institute (CLSI) guideline. For the detection of resistance genes and molecular characterization, PCR reaction was performed by gene specific primers and followed by DNA sequencing. Of the 698 milk samples, 94 Staphylococcus aureus (S. aureus) were identified (94 S. aureus/286 Staphylococcus spp.). Of the 94 S. aureus, seven isolates have mecA, a methicillin resistant gene. mecA positive seven isolates were then characterized by staphylococcal cassette chromosome mec (SCCmec) typing, and Panton-Valentine Leukocidin (pvl) gene using PCR. All of mecA positive isolates were resistant to ampicillin and oxacillin, but sensitive to teicoplanin, vancomycin and ciprofloxacin. One of seven isolates was SCCmec type II and six isolates were type IV and all seven isolates were pvl gene negative.

• Journal of Animal Science and Technology
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• v.64 no.3
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• pp.515-530
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• 2022

Sequence type (ST) 5 methicillin-resistant Staphylococcus aureus (MRSA) with staphylococcal cassette chromosome mec (SCCmec) type II (ST5-MRSA-II) and ST72-MRSA-IV represent the most significant genotypes for healthcare- (HA) and community-associated (CA) MRSA in Korea, respectively. In addition to the human-type MRSA strains, the prevalence of livestock-associated (LA) MRSA clonal lineages, such as ST541 and ST398 LA-MRSA-V in pigs and ST692 LA-MRSA-V and ST188 LA-MRSA-IV in chickens, has recently been found. In this study, clonotype-specific resistance profiles to cathelicidins derived from humans (LL-37), pigs (PMAP-36), and chickens (CATH-2) were examined using six different ST groups of MRSA strains: ST5 HA-MRSA-II, ST72 CA-MRSA-IV, ST398 LA-MRSA-V, ST541 LA-MRSA-V, ST188 LA-MRSA-IV, and ST692 LA-MRSA-V. Phenotypic characteristics often involved in cathelicidin resistance, such as net surface positive charge, carotenoid production, and hydrogen peroxide susceptibility were also determined in the MRSA strains. Human- and animal-type MRSA strains exhibited clonotype-specific resistance profiles to LL-37, PMAP-36, or CATH-2, indicating the potential role of cathelicidin resistance in the adaptation and colonization of human and animal hosts. The ST5 HA-MRSA isolates showed enhanced resistance to all three cathelicidins and hydrogen peroxide than ST72 CA-MRSA isolates by implementing increased surface positive charge and carotenoid production. In contrast, LA-MRSA strains employed mechanisms independent of surface charge regulation and carotenoid production for cathelicidin resistance. These results suggest that human- and livestock-derived MRSA strains use different strategies to counteract the bactericidal action of cathelicidins during the colonization of their respective host species.

• Journal of Veterinary Science
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• v.25 no.1
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• pp.12.1-12.10
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• 2024

Background: Staphylococcus aureus and S. pseudintermedius are the major etiological agents of staphylococcal infections in humans, livestock, and companion animals. The misuse of antimicrobial drugs has led to the emergence of antimicrobial-resistant Staphylococcus spp., including methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP). One novel therapeutic approach against MRSA and MRSP is a peptide nucleic acid (PNA) that can bind to the target nucleotide strands and block expression. Previously, two PNAs conjugated with cell-penetrating peptides (P-PNAs), antisense PNA (ASP)-cmk and ASP-deoD, targeting two essential genes in S. aureus, were constructed, and their antibacterial activities were analyzed. Objectives: This study analyzed the combined antibacterial effects of P-PNAs on S. aureus and S. pseudintermedius clinical isolates. Methods: S. aureus ATCC 29740 cells were treated simultaneously with serially diluted ASP-cmk and ASP-deoD, and the minimal inhibitory concentrations (MICs) were measured. The combined P-PNA mixture was then treated with S. aureus and S. pseudintermedius veterinary isolates at the determined MIC, and the antibacterial effect was examined. Results: The combined treatment of two P-PNAs showed higher antibacterial activity than the individual treatments. The MICs of two individual P-PNAs were 20 and 25 µM, whereas that of the combined treatment was 10 µM. The application of a combined treatment to clinical Staphylococcus spp. revealed S. aureus isolates to be resistant to P-PNAs and S. pseudintermedius isolates to be susceptible. Conclusions: These observations highlight the complexity of designing ASPs with high efficacy for potential applications in treating staphylococcal infections in humans and animals.

• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.97-98
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• 2024

Methicillin-resistant Staphylococcus aureus (MRSA) represents antimicrobial-resistant bacteria that can cause a wide range of illnesses both in humans and animals. Multidrug resistance phenotype is common, especially in healthcare-associated (HA) MRSA strains. Currently, one of the most prevalent HA-MRSA clonal lineages in Korean hospitals is sequence type (ST) 5 carrying staphylococcal cassette chromosome mec type II (ST5-SCCmec II). Here, we report the complete genome sequence of an ST5 HA-MRSA strain (SA492) originated from a patient in Korea.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.800-805
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• 2012

Licochalcone E was firstly isolated from licorice root in 2005, which belongs to the retrochalcone family. Studies on the biological activities of licochalcone E were in the initial stage. In the study, we demonstrated that licochalcone E has potent antimicrobial property against Staphylococcus aureus. Furthermore, via hemolysis, Western blot, and real-time RT-PCR assays, we have shown that subinhibitory concentrations of licochalcone E dose-dependently reduces the production of ${\alpha}$-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). The data suggest that licochalcone E may deserve further investigation as a potential therapeutic against S. aureus infections, or the structure of licochalcone E may be used as a basis for chemical synthesis of novel anti-S. aureus compounds.

• Food Science of Animal Resources
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• v.40 no.3
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• pp.401-414
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• 2020

The emergence and persistence of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in livestock animals have been reported as a potential risk factor for transmission to humans. In this study, we investigated the nationwide prevalence and characteristics of MRSA and MSSA in the Korean beef production system, including retail markets, slaughterhouses, and cattle farms. From a total of 1,285 samples, only 5 MRSA strains were isolated: from a farmer (1 ST72 MRSA), a carcass sample from a slaughterhouse (1 ST72 MRSA), and beef cattle (3 ST5 MRSA). In addition, 11 MSSA strains were isolated from beef cattle (n=3), humans (1 farmer, 1 slaughterhouse worker, and 4 retail market workers), and carcass samples (n=1) and slaughterhouse environment (n=1). Although the prevalence of MRSA and MSSA in beef cattle was much lower than that reported in pigs, 5/5 MRSA and 2/11 MSSA strains displayed multiple drug resistance (MDR) phenotypes. Unlike the swine-associated MRSA, no correlation was found between tetracycline/zinc resistance and MDR phenotype. However, MRSA strains had an identical set of staphylococcal enterotoxins and exhibited enhanced levels of resistance to antimicrobial peptides (PMAP-36 and LL-37) compared to the MSSA strains. In conclusion, continued and systemic surveillance of livestock, meat products, and humans in close contact with livestock/meat products is necessary to prevent the transmission of MRSA and MSSA to humans.