In this study, we investigated the genetic background of 70 Staphylococcus aureus isolates (36 methicillin-resistant S. aureus [MRSA] and 34 methicillin-susceptible S. aureus [MSSA]) obtained from blood at a Korean tertiary-care hospital, using spa typing, multilocus sequence typing, and SCCmec typing. In addition, the prevalence of enterotoxin (sea, seb, sec, sed, see, seg, seh, sei, and sek), tst, and pvl genes among the samples was assessed via polymerase chain reaction, and the results were compared with those of 95 isolates of S. aureus obtained from nasal swabs. All MRSA isolates from blood, except one, belonged to three major clones: sequence type (ST)5-MRSA-II, ST72-MRSA-II (or IVA), and ST239-MRSA-III, among which ST5-MRSA-II was the predominant clone. The prevalence of enterotoxin genes in the S. aureus isolates obtained from blood differed significantly from those from the nasal swabs for the sea, seb, sec, and seh gene. In particular, the seb and sec genes were detected exclusively in the MRSA isolates of ST5 or spa-CC002, thereby suggesting the co-adaptation of virulence genes with the genetic background and their contribution to biological fitness.
Bacteremia/*microbiology ; Enterotoxins/genetics ; Genotype ; Hospitals ; Humans ; Korea ; Methicillin-Resistant Staphylococcus aureus/genetics/*isolation & purification ; Microbial Sensitivity Tests ; Nose/*microbiology ; Staphylococcal Infections/diagnosis/*microbiology ; Staphylococcus aureus/genetics/*isolation & purification

Although coagulase-negative staphylococci (CNS) have been considered part of the resident flora on the human skin, Staphylococcus lugdunensis is an unusually virulent CNS and can cause many types of infection. We report a rare case of acute lymphadenitis with cellulitis in the right infraauricular region caused by S. lugdunensis. A 62-yr-old woman visited the Department of Otolaryngology of Busan Paik university hospital. She had a palpable mass and swelling in the right infraauricular region and complained of aggressive pain and a febrile sensation in the region for 5 days. On the suspicion of abscess with infection, percutaneous aspiration was performed and smooth, flat, white, opaque colonies grew on a blood agar plate as a pure culture. The biochemical test results showed the organism to be catalase positive, tube coagulase negative, ornithine decarboxylase positive, slide coagulase positive, and latex agglutination tests for coagulase positive. The API Staph Kit was used to identify the isolate to the species level as S. lugdunensis with a 64.6% probability (profile 6716152). We confirmed the species identification of this strain by 16S rDNA sequence analysis. The patient's clinical condition improved with appropriate antimicrobial therapy and pus drainage.
Acute Disease ; Cellulitis/*diagnosis/*microbiology ; Drainage ; Ear, External ; Female ; Humans ; Lymphadenitis/*diagnosis/drug therapy/*microbiology ; Microbial Sensitivity Tests ; Middle Aged ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Staphylococcal Infections/*diagnosis/microbiology

No abstract available.
Aged, 80 and over ; Anti-Bacterial Agents/therapeutic use ; Community-Acquired Infections/diagnosis/*microbiology/therapy ; Debridement ; Drainage ; Female ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/classification/genetics/*isolation & purification ; Microbial Sensitivity Tests ; Republic of Korea ; Staphylococcal Infections/diagnosis/*microbiology/therapy ; Treatment Outcome

BACKGROUND: The BD GeneOhm MRSA PCR assay (Becton Dickinson, USA) is a qualitative real-time PCR test for rapid detection of nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA). We evaluated the performance of BD GeneOhm MRSA PCR assay versus MRSASelect (Bio-Rad, France) and broth enrichment cultures for detection of MRSA from nasal swabs. METHODS: From August 2008 to January 2009, 295 nasal swabs were taken from patients in intensive care units and transported to the laboratory with BD CultureSwab Liquid Stuart Single Swab (Becton Dickinson, USA). The swabs were inoculated onto MRSASelect first and then suspended into GeneOhm sample buffer: 100 microliter of the suspension was inoculated into 6.5% NaCl-tryptic soy broth (Becton Dickinson, USA), which was subcultured on MRSASelect after overnight incubation (TSBS). Performances of GeneOhm MRSA and MRSASelect were compared to TSBS. RESULTS: With GeneOhm MRSA, 125 swabs (44.6%) were positive for MRSA, 13 (4.4%) were unresolved, and 2 were not determined. With MRSASelect and TSBS 86 (29.4%) and 106 swabs (36.2%), respectively, were positive. The sensitivity, specificity, and positive and negative predictive value of GeneOhm MRSA were 85.8%, 77.5%, and 72.8% and 93.5%, respectively, and corresponding values for MRSASelect were 78.3%, 94.8%, and 96.5% and 88.9%. Of the 33 patients whose 34 specimens were found false positive in GeneOhm MRSA, 23 patients were MRSA-positive either previously or subsequently to this study. All of the 10 patients with false-negative specimens in GeneOhm MRSA PCR assay were previously MRSA or methicilln-resistant coagulase negative staphylococci (MRCNS)-positive and were treated for MRSA, but they became MRSA-positive after 1 to 4 negative surveillance cultures. CONCLUSIONS: GeneOhm MRSA PCR assay showed a relatively high negative predictive value. However, its low specificity and frequent occurrence of unresolved results would be problematic in the endemic areas with a high prevalence of MRSA.
Endemic Diseases ; Humans ; Intensive Care Units ; Methicillin-Resistant Staphylococcus aureus/genetics/*isolation & purification ; Nose/*microbiology ; Polymerase Chain Reaction/*methods ; Reagent Kits, Diagnostic ; Sensitivity and Specificity ; Staphylococcal Infections/*diagnosis/epidemiology

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

Staphylococcus aureus, or methicillin-resistant S. aureus (MRSA), is a significant pathogen in both nosocomial and community infections. Community-associated MRSA (CA-MRSA) strains tend to be multi-drug resistant and to invade hospital settings. This study aimed to assess the antimicrobial resistance and molecular characteristicsof nasal S. aureus among newlyadmitted inpatients.In the present study, 66 S. aureus isolates, including 10 healthcare-associated MRSA (HA-MRSA), 8 CA-MRSA, and 48 methicillin-sensitive S. aureus (MSSA) strains, were found in the nasal cavities of 62 patients by screening 292 newlyadmitted patients. Antimicrobial resistance and molecular characteristics of these isolates, including spa-type, sequence type (ST) and SCCmec type, were investigated. All isolates were sensitive to linezolid, teicoplanin, and quinupristin/dalfopristin, but high levels of resistance to penicillin and erythromycin were detected. According to D-test and erm gene detection results, the cMLSB and iMLSB phenotypes were detected in 24 and 16 isolates, respectively. All 10 HA-MRSA strains displayed the cMLSB phenotypemediated by ermA or ermA/ermC, while the cMLSB CA-MRSA and MSSA strains carried the ermB gene. Molecular characterization revealedall 10 HA-MRSA strains were derived from the ST239-SCCmec III clone, and four out of eight CA-MRSA strains were t437-ST59-SCCmec V. The results suggest that patients play an indispensable role in transmitting epidemic CA-MRSA and HA-MRSA strains.
Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Drug Resistance, Multiple, Bacterial/genetics ; Humans ; Inpatients ; Methicillin-Resistant Staphylococcus aureus/*drug effects/genetics/isolation & purification ; Methyltransferases/genetics ; Microbial Sensitivity Tests ; Nasal Cavity/*microbiology ; Staphylococcal Infections/diagnosis/microbiology ; Staphylococcus aureus/*drug effects/genetics/isolation & purification

BACKGROUND: Coagulase is produced by all strains of Staphylococcus aureus. The 3' coding region of the coagulase (coa) gene contains varying numbers of 81 bp tandem repeats. S. aureus produces a variety of extracellular protein toxins. Here, we typed S. aureus strains isolated from blood by coa gene restriction fragment length polymorphism (RFLP) patterns and toxin gene profiles. METHODS: A total of 120 strains of S. aureus were isolated from blood cultures during 2003-2006 at Kangdong Sacred Heart Hospital. The isolates were typed by PCR RFLP analysis of the coa gene and by multiplex PCR for detection of genes encoding enterotoxins (sea, seb, sec, sed, and see), toxic shock syndrome toxin-1 (tst), exfoliative toxins (eta and etb), mecA and femA. RESULTS: All the S. aureus strains were classified into 16 types on the basis of coa gene RFLP and could be further differentiated into 34 types according to the combined patterns of coa gene RFLP and toxin gene profiles. Of 85 methicillin-resistant S. aureus (MRSA) strains, 43 (50.6%) and 36 (42.4%) belonged to the RFLP pattern L5 and pattern L1, respectively. MRSA strains belonging to pattern L5 frequently carried tst (93.0%) or sec gene (81.4%), and strains belonging to pattern L1 frequently carried sea (88.9%) or see gene (44.4%). The rate of the pattern L5 in MRSA strains increased over the past few years and was higher in intensive care unit than in other wards. CONCLUSIONS: We typed S. aureus strains isolated from blood on the basis of coa gene RFLP and toxin genes. The strains belonging to coa gene RFLP pattern L5 and L1 appeared to be the major types of MRSA isolasted from bacteremia and revealed specific toxin gene profiles according to the coa gene RFLP patterns.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Bacterial Proteins/genetics ; Bacterial Typing Techniques ; Child ; Child, Preschool ; Coagulase/*genetics ; Female ; Humans ; Infant ; Male ; Methicillin Resistance/genetics ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Staphylococcal Infections/*diagnosis/genetics/microbiology ; Staphylococcus aureus/*classification/genetics/isolation & purification ; Toxins, Biological/*genetics ; Young Adult

Severe congenital neutropenia (SCN) is a heterogeneous group of disorders with a defect in granulopoiesis causing marked neutropenia and severe bacterial infections. A 17-month-old girl (patient 1) was admitted due to cervical lymphadenitis caused by methicillin-resistant Staphylococcus aureus, with neutropenia. She had Pseudomonas aeruginosa sepsis and peritonitis with perforated appendicitis at 8-month of age. Her sister, a 37-month-old girl (patient 2), had recurrent stomatitis with profound neutropenia, and her mother, a 32-yr-old woman (patient 3), had had recurrent stomatitis until her early 20s with neutropenia. We found an ELANE gene mutation (c.597+1G > A) from them in direct DNA sequencing analysis. Patients 1 and 2 did not respond to granulocyte colony stimulating factor and patient 1 was treated with prolonged antibiotics and excision. We demonstrated inherited SCN cases showing different severity even with the same mutation of the ELANE gene in a family.
Adult ; Child, Preschool ; DNA Mutational Analysis ; Female ; Granulocyte Colony-Stimulating Factor/therapeutic use ; Humans ; Infant ; Leukocyte Elastase/*genetics ; Methicillin-Resistant Staphylococcus aureus/isolation & purification ; Mutation/genetics ; Neutropenia/*congenital/diagnosis/drug therapy/genetics ; Pedigree ; *Phenotype ; Polymorphism, Single Nucleotide ; Recurrence ; Staphylococcal Infections/diagnosis/microbiology ; Stomatitis/diagnosis ; Tomography, X-Ray Computed

BACKGROUND: We evaluated the performance of three chromogenic media (Brilliance agar I [Oxoid, UK], Brilliance agar II [Oxoid], and ChromID MRSA [Biomerieux, France]) combined with broth enrichment and the Xpert MRSA assay for screening of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: We obtained 401 pairs of duplicate nasal swabs from 321 patients. One swab was suspended overnight in tryptic soy broth; 50-microL aliquots of suspension were inoculated on the three chromogenic media. Brilliance agar I and II were examined after 24 hr, and ChromID MRSA, after 24 and 48 hr. The paired swab was processed directly using real-time PCR-based Xpert MRSA assay. RESULTS: True positives, designated as MRSA growth in any of the culture media, were detected with the prevalence of 17% in our institution. We report the sensitivity, specificity, positive predictive value, and negative predictive value of MRSA growth as follows: 92.3%, 94.0%, 75.9%, and 98.4% in Brilliance agar I (24 hr); 92.7%, 97.9%, 90.0%, and 98.5% in Brilliance agar II (24 hr); 95.6%, 95.8%, 82.3%, and 99.1% in ChromID MRSA (24 hr); 100%, 92.5%, 73.1%, and 100% in ChromID MRSA (48 hr); 92.6%, 96.7%, 85.1%, and 98.5% in Xpert MRSA assay. The agreement between the enriched culture and Xpert MRSA assay was 96.0%. CONCLUSIONS: Three chromogenic culture media combined with enrichment and Xpert MRSA assay demonstrated similar capabilities in MRSA detection. The Xpert MRSA assay yielded results comparable to those of culture methods, saving 48-72 hr, thus facilitating earlier detection of MRSA in healthcare settings.
Bacterial Proteins/genetics ; Bacterial Typing Techniques/*methods ; Chromogenic Compounds/chemistry/*metabolism ; Culture Media/chemistry ; DNA, Bacterial/analysis ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/growth & development/*isolation & purification/metabolism ; Nasal Cavity/*microbiology ; Reagent Kits, Diagnostic ; *Real-Time Polymerase Chain Reaction ; *Staphylococcal Infections/diagnosis/microbiology