BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) are important pathogens causing nosocomial infections in Korean hospitals. This study aimed to investigate the epidemiological and genetic diversity of clinical S. aureus isolates in healthcare settings from 2001 to 2008. METHODS: Samples and data were obtained from 986 individuals as part of the National Antimicrobial Surveillance Project, involving 10 regions nationwide. Molecular typing studies, including multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing were performed, and a representative clone of Korean MRSA was classified by combinational grouping using a DiversiLab (DL; bioMérieux, France) repetitive element polymerase chain reaction (rep-PCR) system. RESULTS: Nine Korean MRSA clones (KMRSA-1 to -9) were identified by analysis of genetic backgrounds and molecular characteristics. KMRSA-1 to -3, expressing clonal complex (CC) 5 (carrying SCCmec II), CC8 (carrying SCCmec III), and CC72 (carrying SCCmec IV) were spread nationwide. In contrast, KMRSA-6 was highly prevalent in Gyeongsangnam-do, and KMRSA-4 was highly prevalent in Jeollanam-do and Jeollabuk-do. CONCLUSIONS: Epidemic KMRSA clones were genetically similar to major clones identified from the USA, with the exception of KMRSA-2, which had the SCCmec III type. Our results provide important insights into the distribution and molecular genetics of MRSA strains in Korea and may aid in the monitoring of MRSA spread throughout the country.
Bacterial Proteins/genetics ; DNA, Bacterial/genetics/metabolism ; Electrophoresis, Gel, Pulsed-Field ; Hospitals ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/isolation & purification ; Multilocus Sequence Typing ; Multiplex Polymerase Chain Reaction ; Prevalence ; Republic of Korea/epidemiology ; Staphylococcal Infections/diagnosis/*epidemiology/microbiology

BACKGROUND: Burn wounds lack normal barriers that protect against pathogenic bacteria, and burn patients are easily colonized and infected by Staphylococcus aureus. Toxic shock syndrome (TSS) is a rare but fatal disease caused by S. aureus. A lack of detectable antibodies to TSS toxin-1 (TSST-1) in serum indicates susceptibility to TSS. METHODS: A total of 207 patients (169 men and 38 women; median age, 42.5 yr) admitted to a burn center in Korea were enrolled in this study. The serum antibody titer to TSST-1 was measured by sandwich ELISA. S. aureus isolates from the patients' nasal swab culture were tested for TSST-1 toxin production by PCR-based detection of the TSST-1 toxin gene. RESULTS: One hundred seventy-four (84.1%) patients showed positive results for antibody against TSST-1. All patients aged > or =61 yr (n=28) and <26 months (n=7) were positive for the anti-TSST-1 antibody. S. aureus was isolated from 70 patients (33.8%), and 58.6% of the isolates were methicillin resistant. Seventeen patients were colonized with TSST-1-producing S. aureus. The antibody positivity in these 17 carriers was 88.2%, and the positivity in the non-carriers was 83.7%. CONCLUSIONS: Most burn patients had antibody to TSST-1, and nasal colonization with TSST-1-producing S. aureus was associated with positive titers of anti-TSST-1 antibody. Additionally, patients with negative titers of anti-TSST-1 antibody might be susceptible to TSS.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antibodies, Bacterial/*blood ; Bacterial Toxins/genetics/immunology/*metabolism ; Burns/blood/*immunology/*microbiology/pathology ; Child ; Child, Preschool ; Enterotoxins/genetics/immunology/*metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Infant ; Male ; Middle Aged ; Nasal Cavity/microbiology ; Polymerase Chain Reaction ; Prevalence ; Staphylococcal Infections/epidemiology ; Staphylococcus aureus/isolation & purification/*metabolism ; Superantigens/genetics/immunology/*metabolism ; Young Adult

This study was conducted to determine the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs, farm workers, and the environment in northern Thailand, and to assess LA-MRSA isolate phenotypic characteristics. One hundred and four pig farms were randomly selected from the 21,152 in Chiang Mai and Lamphun provinces in 2012. Nasal and skin swab samples were collected from pigs and farm workers. Environmental swabs (pig stable floor, faucet, and feeder) were also collected. MRSA was identified by conventional bacterial culture technique, with results confirmed by multiplex PCR and multi locus sequence typing (MLST). Herd prevalence of MRSA was 9.61% (10 of 104 farms). Among pigs, workers, and farm environments, prevalence was 0.68% (two of 292 samples), 2.53% (seven of 276 samples), and 1.28% (four of 312 samples), respectively. Thirteen MRSA isolates (seven from workers, four from environmental samples, and two from pigs) were identified as Staphylococcal chromosomal cassette mec IV sequences type 9. Antimicrobial sensitivity tests found 100% of the MRSA isolates resistant to clindamycin, oxytetracycline, and tetracycline, while 100% were susceptible to cloxacillin and vancomycin. All possessed a multidrug-resistant phenotype. This is the first evidence of an LA-MRSA interrelationship among pigs, workers, and the farm environment in Thailand.
*Animal Husbandry ; Animals ; Cross-Sectional Studies ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/classification/*genetics/*isolation & purification ; Microbial Sensitivity Tests/veterinary ; Molecular Sequence Data ; Multilocus Sequence Typing/veterinary ; Multiplex Polymerase Chain Reaction/veterinary ; Occupational Diseases/*epidemiology/microbiology ; Phylogeny ; Prevalence ; Sequence Analysis, DNA/veterinary ; Staphylococcal Infections/*epidemiology/microbiology ; Swine ; Swine Diseases/*epidemiology/microbiology ; Thailand/epidemiology

OBJECTIVETo investigate the genotype of staphylococcal chromosomal cassette mec (SCCmec) in methicillin-resistant Staphylococcus aureus (MRSA) isolated from burn wards and its current status of drug resistance.

METHODSOne hundred and seventy-nine strains of Staphylococcus aureus were isolated from wound excretion, blood, and sputum samples of patients that were admitted to ICU or public wards of our Department of Burns and Plastic Surgery from September 2012 to September 2013. Among them, 68 strains were from ICU and 111 strains from public wards. The MRSA phenotype of Staphylococcus aureus was detected with cefoxitin K-B disk diffusion method, and the isolation rates of MRSA in ICU and public wards were compared. Genotyping of SCCmec was performed by PCR in strains of MRSA. In the meantime, the identification result of MRSA by K-B method was verified through detecting methicillin-resistant determinant mecA. The antimicrobial resistance of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) to 23 kinds of commonly used antibiotics in clinic were detected by K-B disk diffusion method. Except for the antibiotics to which the resistant rates of MRSA were 100.0% or 0, the resistant rates of SCCmecIII MRSA and non-SCCmec III MRSA to the rest of antibiotics were compared. Data were processed with Pearson chi-square test or corrected chi-square test.

RESULTSOne hundred and forty-eight strains out of the 179 Staphylococcus aureus were identified as MRSA (accounting for 82.7%), among which 62 were originated from ICU and 86 from public wards. The rest 31 strains of Staphylococcus aureus were MSSA, accounting for 17.3%. The percentage of MRSA in the isolated Staphylococcus aureus was 91.2% (62/68) in ICU, which was significantly higher than that in the public wards [77.5% (86/111), χ2 = 5.526, P = 0.019]. PCR detection showed that the 148 strains of MRSA harbored the mecA gene, out of which 106 strains were SCCmec III positive, accounting for 71.6%. The percentages of SCCmec III type MRSA in MRSA isolated from ICU and public wards were respectively 72.6% (45/62) and 70.9% (61/86), showing no statistically significant difference (χ2 = 0.048, P = 0.826). The 148 strains of MRSA were 100.0% resistant to a total of 8 kinds of antibiotics including penicillin and cephalosporins, but it was 0 for vancomycin, teicoplanin, linezolid, tigecycline, nitrofurantoin, and quinupristin/dalfopristin. Except for the 6 kinds of antibiotics to which the resistant rates of MRSA and MSSA were 0, resistant rates of MRSA to the remaining 17 kinds of antibiotics were significantly higher than those of MSSA (with χ2 values from 4.091 to 138.546, P < 0.05 or P < 0.01). Resistant rates of the 106 strains of SCCmecIII type MRSA to levofloxacin, ciprofloxacin, rifampicin, tetracycline, erythrocin, lincomycin, gentamicin, clindamycin were respectively 56.6% (60/106), 85.8% (91/106), 89.6% (95/106), 86.8% (92/106), 84.9% (90/106), 78.3% (83/106), 92.5% (98/106), 74.5% (79/106), and they were significantly higher than those of the 42 strains of non-SCCmec III type MRSA [33.3% (14/42), 61.9% (26/42), 71.4% (30/42), 66.7% (28/42), 69.0% (29/42), 57.1% (24/42), 71.4% (30/42), 52.4% (22/42), with χ2 values from 4.801 to 11.377, P < 0.05 or P < 0.01].

CONCLUSIONSIsolation rate of MRSA from burn wards in our hospital is high, and drug resistance status of this strain against antibiotics is very serious. SCCmec III is the major genotype of the isolated MRSA, but no strains resistant to the glycopeptide antibiotics are found.

Anti-Bacterial Agents ; pharmacology ; Burns ; microbiology ; Drug Resistance, Bacterial ; genetics ; Drug Resistance, Multiple ; Genes, Bacterial ; genetics ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; genetics ; isolation & purification ; Microbial Sensitivity Tests ; Staphylococcal Infections ; drug therapy ; epidemiology

We investigated the distribution of commensal staphylococcal species and determined the prevalence of multi-drug resistance in healthy cats and dogs. Risk factors associated with the carriage of multi-drug resistant strains were explored. Isolates from 256 dogs and 277 cats were identified at the species level using matrix-assisted laser desorption ionisation-time of flight mass spectrometry. The diversity of coagulase-negative Staphylococci (CNS) was high, with 22 species in dogs and 24 in cats. Multi-drug resistance was frequent (17%) and not always associated with the presence of the mecA gene. A stay in a veterinary clinic in the last year was associated with an increased risk of colonisation by multi-drug resistant Staphylococci (OR = 2.4, 95% CI: 1.1~5.2, p value LRT = 0.04). When identifying efficient control strategies against antibiotic resistance, the presence of mechanisms other than methicillin resistance and the possible role of CNS in the spread of resistance determinants should be considered.
Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Cat Diseases/epidemiology/*microbiology ; Cats ; Coagulase/genetics/metabolism ; Dog Diseases/epidemiology/*microbiology ; Dogs ; *Drug Resistance, Multiple, Bacterial ; Female ; Male ; Prevalence ; Risk Factors ; Seasons ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/veterinary ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus/classification/genetics/*isolation & purification ; Switzerland/epidemiology

The sequences of the ccrAB genes from bovine-, canine- and chicken-originating methicillin-resistant Staphylococcus (S.) epidermidis (MRSE) and bovine methicillin-resistant Staphylococcus (S.) aureus (MRSA) were compared to investigate the frequency of intra-species horizontal transfer of the staphylococcal cassette chromosome mec (SCCmec) complex. Nineteen MRSE strains were isolated from bovine milk, chickens, and dogs, and their genetic characteristics were investigated by multilocus sequence typing and SCCmec typing. Among the animal MRSE strains, the most frequent SCCmec type was type IV, which consisted of the type B mec complex and ccrAB type 2. The ccrA2 and ccrB2 genes were sequenced from the bovine, chicken and canine MRSE strains and compared with those of the bovine MRSA strains. The sequences generally clustered as MRSA and MRSE groups, regardless of the animal source. Additionally, no bovine MRSE sequence was associated with the bovine MRSA groups. Although most of the bovine MRSE and MRSA isolates possessed SCCmec type IV sequences, our results suggest that the intra-species gene transfer of the SCCmec complex between bovine S. aureus and bovine S. epidermidis strains is not a frequent event.
Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/*genetics/metabolism ; Bacterial Typing Techniques/veterinary ; Cattle ; Cattle Diseases/epidemiology/metabolism ; Chickens ; Dog Diseases/epidemiology/metabolism ; Dogs ; *Drug Resistance, Bacterial ; *Gene Transfer, Horizontal ; Methicillin/*pharmacology ; Methicillin-Resistant Staphylococcus aureus/genetics/isolation & purification ; Milk/microbiology ; Multilocus Sequence Typing/veterinary ; Poultry Diseases/epidemiology/metabolism ; Prevalence ; Republic of Korea/epidemiology ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus epidermidis/genetics/isolation & purification

OBJECTIVETo genotypically characterize methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from medical and surgical wards in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in 2009.

METHODSMRSA strains were collected and molecularly typed by pulsed-field gel electrophoresis (PFGE).

RESULTSPFGE typing on 180 MRSA isolated in UKMMC identified 5 pulsotypes (A-E) and 6 singletons, where pulsotypes B and C were suspected to be divergent clones originating from a single ancestor. This study also showed that most MRSA strains were isolated from swab (119 isolates), followed by blood (22 isolates), tracheal aspirate (11 isolates) and sputum (10 isolates). On the other hand, urine and bone isolates were less, which were 4 and 1 isolates, respectively. The distribution of different pulsotypes of MRSA among wards suggested that MRSA was communicated in surgical and medical wards in UKMMC, with pulsotype B MRSA as the dominant strain. Besides, it was found that most deceased patients were infected by pulsotype B MRSA, however, no particular pulsotype could be associated with patient age, underlying disease, or ward of admittance.

CONCLUSIONSFive pulsotypes of MRSA and 6 singletons were identified, with pulsotype B MRSA as the endemic strains circulating in these wards, which is useful in establishment of preventive measures against MRSA transmission.

Electrophoresis, Gel, Pulsed-Field ; Evolution, Molecular ; Hospitals ; Malaysia ; epidemiology ; Methicillin-Resistant Staphylococcus aureus ; genetics ; isolation & purification ; Staphylococcal Infections ; epidemiology ; microbiology

OBJECTIVETo study the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in children.

METHODA total of 37 MRSA strains were isolated from hospitalized patients in Children's Hospital of Fudan University from March 2009 to November 2011. The clinical characteristics were investigated by a cohort study. Furthermore, the mecA, Panton-Valentine leucocidin (PVL) genes were detected by polymerase chain reaction (PCR), and the genotypes of SCCmec were determined by multiplex PCR.

RESULT(1) Among the 37 MRSA isolates, infections with 21 were acquired from hospital (HA-MRSA), and 16 isolates were acquired from community (CA-MRSA). (2) In the study, MRSA frequently caused respiratory tract infection, and most of the strains were isolated from intensive care unit (ICU). (3) CA-MRSA was most frequently associated with skin and soft tissue infections (SSTI), suppurative tonsillitis, even pneumonia and septicemia. HA-MRSA infection was more aggressive, most frequently associated with pneumonia, septicemia, and central nervous system (CNS) infections, such as meningitis. In children with fever caused by HA-MRSA or CA-MRSA infection, HA-MRSA showed a longer duration of fever, for 10.5 days. C-reactive protein (CRP) level caused by HA-MRSA (63.00 mg/L) was higher than CA-MRSA (9.50 mg/L) , and there were statistically significant differences between the groups (t = 2.5670, P < 0.05). However, there were no statistically significant differences between the groups in white blood cell count (WBC) or procalcitonin (PCT) level. (4) Among 37 MRSA isolates, the whole isolates were mecA gene positive (100%). SCCmec genotyping results showed that the most frequent SCCmec types were type III, 17 isolates, the others including type IV 8 isolates, type II1 isolates, nontypable 11 isolates, type I and type V were not found in this group. Therein, among 21 HA-MRSA isolates, SCCmec III was the most common, 15 isolates, type IV 1 isolates, nontypable 5 isolates; among 16 CA-MRSA isolates, SCCmec type IV was the most common, 7 isolates, type III 2 isolates, type II 1 isolate, nontypable 6 isolates. (5) Among the 37 MRSA isolates, 28 were PVL gene positive; and among 21 HA-MRSA isolates, 17 were PVL gene positive; Among 16 CA-MRSA isolates, 11 were PVL gene positive; There were no statistically significant differences between the groups (χ(2) = 0.735, P > 0.05) .

CONCLUSIONCompared with CA-MRSA, HA-MRSA infection was more aggressive, and induced higher C reactive protein; the dominant epidemic strains of CA-MRSA was SCCmec type IV, and HA-MRSA was SCCmec type III; the positive rate of PVL gene was high.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Bacterial Toxins ; genetics ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; Cohort Studies ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; epidemiology ; microbiology ; DNA, Bacterial ; genetics ; Female ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin ; pharmacology ; Methicillin Resistance ; genetics ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Penicillin-Binding Proteins ; Staphylococcal Infections ; epidemiology ; microbiology

OBJECTIVETo investigate the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Chinese children in seven cities.

METHODA total of 134 MRSA isolates were collected from nine hospitals. Multilocus sequence typing and spa typing were analyzed by polymerase chain reaction (PCR), and staphylococcal chromosomal cassette mec (SCCmec) type was analyzed by multiplex PCR. The Panton-Valentine leukocidin (pvl) gene was also detected.

RESULTMost MRSA strains were isolated from pneumonia and skin and soft tissue infection (SSTIs) patients, accounting for 82.1%. Overall, 16 sequence types (STs) were obtained, and CC59 (51.7%) was found to be the most prevalent, which included ST 59 and ST 338, followed by ST239 (16.4%). SCCmec types II, III, IV, and V were also identified in the current study. SCCmec type IV was the most predominant type at 50.0%, followed by SCCmec type V at 23.9% and III at 23.9%. SCCmec subtypes IVa, IVc, and IVg were found among SCCmec type IV strains, whereas IVa was the main subtype at 77.6%. Twenty-six spa types were also identified, among which the predominant type was t437 (47.8%). The prevalence of pvl genes and the SCCmec type of strain was relevant, and the pvl gene positive rate was higher in SCCmec type IV and V-type strains than in SCCmec type II and III strains (58.6% vs. 14.3%, P < 0.05); there was a significant difference between them. In the strains isolated from pneumonia and SSTIs, ST59-MRSA-IVa(t437) was the predominant clone. There were five clones detected from the strains isolated from septicemia, with ST59-MRSA-IVa(t437) and ST59-MRSA-V(t437) as the main clones (57.1%). Various predominant clones existed in different regions. ST59-MRSA-IVa(t437) was the prevalent clone in the Guangzhou, Beijing, Chongqing, and Shenzhen areas, whereas ST239-MRSA-III(t037) was the prevalent clone in the Shanghai area. Fifty percent of the isolates from the Wenzhou area belonged to ST910-MRSA-V(t318), whereas three clinical strains isolated from the Shenyang region belonged to three different types.

CONCLUSIONThe results indicate that MRSA isolates from Chinese children are largely associated with the ST59-MRSA-IV(t437) and ST239-MRSA-III(t037) clones. These two may belong to community-acquired MRSA and hospital-acquired ones, respectively. Different prevalent clones were detected in different diseases and different regions. Therefore, there is a need to conduct further research on clinical isolates, which can guide the choice of antibiotic treatment and the examination of MRSA prevalence.

Adolescent ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; DNA, Bacterial ; genetics ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Prevalence ; Staphylococcal Infections ; epidemiology ; microbiology

The present study determined the genetic relationships between 41 Staphyloccocus (S.) aureus isolates from bovines, humans, and food using a single enzyme amplified fragment length polymorphism (AFLP) technique. We evaluated the prevalence of staphylococcal enterotoxin (SE) genes and other virulence gene determinants by PCR. The identification of S. aureus was based on culturing and biochemical tests, and by amplifying a specific section of the 23S rRNA gene. PCR amplification of the SE genes (sea, seb, sec, see, seg, seh, and sei) singly or in combination was observed. Most isolates of bovine origin harbored hla (84%) and cap5 (74%), while most isolates from humans harbored hla (73%), cap8 (91%), and fnbA (100%). Strains from food sources were positive for hla (100%), cap5 (100%), and cap8 (64%) unlike isolates from humans or bovines. A single enzyme AFLP analysis revealed a correlation between AFLP clusters of some strains and the source of the isolates The genotypic results of the present study might help to better understand the distribution of prevalent S. aureus clones among humans, bovines, and food and will help control S. aureus infections in Indonesia.
Amplified Fragment Length Polymorphism Analysis ; Animals ; Bacterial Proteins/genetics/metabolism ; Cattle ; Female ; *Food Microbiology ; Gene Expression Regulation, Bacterial ; Humans ; Indonesia/epidemiology ; Mastitis, Bovine/epidemiology/microbiology ; Phylogeny ; Staphylococcal Infections/epidemiology/microbiology/*veterinary ; Staphylococcus aureus/*genetics