RESUMEN
Infective endocarditis is a rare condition in humans and is associated with high illness and death rates. We describe a case of infective endocarditis caused by Staphylococcus succinus bacteria in France. We used several techniques for susceptibility testing for this case to determine the oxacillin profile.
Asunto(s)
Endocarditis Bacteriana , Endocarditis , Humanos , Endocarditis Bacteriana/diagnóstico , Endocarditis Bacteriana/tratamiento farmacológico , Staphylococcus , Francia/epidemiologíaRESUMEN
A small peptide called PSM-mec is encoded on the type II, III and VIII SCCmec cassettes present in the genomes of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) strains. This peptide is excreted by agr-positive strains, which represent about 89% of the strains of our collection and can be identified by the presence of delta toxin in mass spectrometry. The presence of the peptide in the MALDI-TOF MS spectra of whole cells was proved by a knock-down experiment employing a clone that expressed antisense RNA to psm-mec. Furthermore, evaluation of a collection of clinical agr-positive MRSA and MSSA isolates and type strains showed that, using a detection window of m/z 2411-2419, the PSM-mec is detected by mass spectrometry of whole cells with a sensitivity of 0.95 and a specificity of 1, thereby enabling rapid identification of a subgroup of MRSA with a method that is used during routine identification procedures.
Asunto(s)
Toxinas Bacterianas/análisis , Staphylococcus aureus Resistente a Meticilina/química , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Proteínas Bacterianas/genética , Humanos , Staphylococcus aureus Resistente a Meticilina/clasificación , Staphylococcus aureus Resistente a Meticilina/genética , Proteínas de Unión a las Penicilinas , Sensibilidad y Especificidad , Transactivadores/genéticaRESUMEN
OBJECTIVES: Differences in virulence genes, including psm-mec, which is a phenol-soluble modulin-mec (PSM-mec) encoding gene, of predominant staphylococcal cassette chromosome mec (SCCmec) types II and IV Methicillin-resistant Staphylococcus aureus (MRSA) may contribute to the virulence and clinical features of MRSA in Japan. We aimed to clarify the clinical characteristics and risk factors of infection among SCCmec types II and IV MRSA isolates from a Japanese secondary acute care hospital. METHODS: We analysed 58 SCCmec type II and 83 SCCmec type IV MRSA isolates collected from blood, central venous catheter tips, deep or superficial tissues, and sputum. RESULTS: SCCmec type II MRSA risk factors for progression to infection were seb, enterotoxin gene cluster, psm-mec mutation, and vancomycin minimum inhibitory concentrations (MIC) of 1 or 2 mg/L as virulence factors (adjusted odds ratio [aOR] = 11.8; 95% confidence interval [CI]: 2.49-77.7; P = 0.004); solid tumour was a host factor (aOR = 25.9; 95% CI: 3.66-300; P = 0.003). SCCmec type IV MRSA risk factors were sea, cna, and vancomycin MIC of 1 or 2 mg/L as virulence factors (aOR = 3.14; 95% CI: 1.06-10.6; P = 0.049) and intravascular indwelling catheter as host factors (aOR = 3.78; 95% CI: 1.03-14.5; P = 0.045). Compared with SCCmec type II, SCCmec type IV MRSA resulted in more frequent bloodstream infections and higher Sequential Organ Failure Assessment scores. CONCLUSION: We found that factors related to virulence genes and bacteriological and host characteristics are associated with SCCmec types II and IV MRSA infection and severity. These risk factors may be useful criteria for designing infection control programs.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Vancomicina/farmacología , Estudios Retrospectivos , Infecciones Estafilocócicas/epidemiología , Atención Secundaria de Salud , Pueblos del Este de Asia , Staphylococcus/genética , Factores de Virulencia/genética , CromosomasRESUMEN
Methicillin-susceptible S. aureus changes to methicillin-resistant S. aureus (MRSA) upon the acquisition of staphylococcal cassette chromosome mec (SCCmec), a genomic island that encodes methicillin resistance. SCCmec elements in S. aureus are classified into different types based on the combination of mec gene complexes and ccr gene complexes, which share variations, five classes in mec and eight in ccr. To date, at least 13 types of SCCmec elements have been identified and each SCCmec type has individual characteristics. It is known that hospital-associated MRSA strains carry SCCmec elements of types, I, II, and III, and the majority of community-acquired MRSA strains carry characteristic SCCmec elements, type IV SCCmec or type V SCCmec. We herein describe multiplex PCR methods to type SCCmec elements by identifying the mec gene complex class and ccr gene complex type.
Asunto(s)
Cromosomas Bacterianos/genética , Técnicas de Genotipaje , Resistencia a la Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/genética , Reacción en Cadena de la Polimerasa MultiplexRESUMEN
Methicillin-resistant coagulase-negative staphylococci (MRCoNS) are major nosocomial pathogens which cause device-related infections. Presence of various virulence factors along with methicillin resistance favor improved CoNS pathogenicity and their dissemination among population. In the present study, mec gene prevalence was analyzed along with SCC mec diversity among 55 human clinical CoNS isolates. PCR screening of insertion sequence (IS256) was also conducted to elucidate their association with methicillin resistance among selected CoNS species. In addition to this, PCR screening and sequence analysis of novel colonization-associated gene sasX was also carried out. High incidences of mec gene, IS256 and their association have been noted among all of the CoNS species tested. Interestingly, eight CoNS isolates were found to harbor sasX gene including S. epidermidis, S. hemolyticus and S. saprophtyicus species. Remarkably they were also found to have the coexistence of mec gene and IS256 in their genome. Increased SCC mec diversity with non-typeable elements was also observed among CoNS isolates. Presence of sasX gene in CoNS with mec gene and insertion sequence 256 and also the identification of non-typeable SCC mec element make the study novel and interesting.
RESUMEN
Methicillin resistant Staphylococcus aureus (MRSA) is highly prevalent, and its typing plays a crucial role in epidemiology and evolution in both health and community settings. Multiplex PCR and staphylococcal cassette chromosome mec (SCCmec) typing based on mec complexes and cassette chromosome recombinase (ccr) allotypes have been developed for MRSA identification. The first of these procedures can identify 4 mec classes (A, B, C1, and E) and 2 ccr allotypes (B2 and B4) in one tube, and the second can identify mecA, mec class C2, and 3 allotypes (A1, A3, and C). Our method offers a novel means to further differentiate between the main SCCmec types I through XI and is both highly sensitive (detectable up to 0.3ηg DNA) and specific (100%). Several SCCmec types (I, III, IV, V and a non-typeable group) were found in 66 MRSA isolates obtained from Ho Chi Minh City, Vietnam and Nakhon Pathom, Thailand. SCCmec type III was highly predominant in both regions. The designed assay is rapid, convenient, flexible, and reliable. Therefore, this assay is suitable for the high-throughput screening of the main SCCmec types of MRSA isolates.
Asunto(s)
Proteínas Bacterianas/genética , Resistencia a la Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/clasificación , Staphylococcus aureus Resistente a Meticilina/genética , Reacción en Cadena de la Polimerasa Multiplex/métodos , Infecciones Estafilocócicas/microbiología , Antibacterianos/farmacología , Humanos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Reacción en Cadena de la Polimerasa Multiplex/normas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Infecciones Estafilocócicas/epidemiología , Tailandia , VietnamRESUMEN
Objective To investigate the genetic location of SCCmec-associated psm-mec in Staphylococcus hominis isolated from blood culture,and to lay a foundation for further functional studies of psm-mec in Staphylococcus hominis.Methods 25 strains of Staphylococcus hominis isolated from positive blood culture were collected.mecA and psm-mec gene were amplified by PCR,and the SCCmec types were determined by the results of multiplex PCR assay.For analyzing the genetic location characteristic of psm-mec in SCCmec,three pair special PCR primers were used to measure mecR1/psm-mec,psm-mec/xylR and fudoh respectively.Results There were 21 strains of methicillin-resistant Staphylococcus hominis and 4 strains of methicillin-sensitive Staphylococcus hominis. The positive rate of psm-mec gene in methicillin-resistant Staphylococcus hominis was 47.6%,and no psm-mec gene was found in methicillin-sensitive Staphylococcus hominis.Among psm-mec positive strains,2 strains belonged to SCCmecⅢ,5 strains belonged to SCCmecⅢ-like,and 3 strains belonged to new SCCmec types.All of the 10 psm-mec positive strains were mecR1/psm-mec,psm-mec/xylR and fudoh gene positive.Conclusion SCCmec-associated psm-mec extensively exists in methicillin-resistant Staphylococ-cus hominis isolated from positive blood culture,which distributes mainly in typical SCCmecⅢ,SCCmecⅢ-like and new SCCmec types and locates between mecR1 and xylR gene.