VraSR has an important role in immune evasion of Staphylococcus aureus with low level vancomycin resistance.

Vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) are increasingly being reported as associated with treatment failure. Previous studies indicated that VISA/hVISA resists clearance by the host immune system, thereby allowing persistence within the host. VraSR is a vancomycin-resistance-associated sensor/regulator that is highly expressed in VISA/hVISA strains. Whether VraSR plays an important role in immune escape by VISA/hVISA strains is unclear. Here, we constructed a vraSR deletion mutant strain (ΔvraSR) and complementary strain (CΔvraSR) in Mu3 to investigate the effect of VraSR on S. aureus viability in polymorphonuclear leukocytes (PMNs). The ΔvraSR strain was more susceptible to phagocytosis by PMNs and reduced the ability of S. aureus to survive within PMNs. ΔvraSR showed phenotypic changes, including a thinner cell wall, reduced adhesion, and decreased biofilm-forming ability. Real-time quantitative PCR revealed that the transcript levels of cell wall synthesis-related genes (cap5K, cap5N, nanA, tagA, murD) and adhesion-associated genes (fnbA, fnbB, clfA, ebps, sbi) were significantly decreased in the ΔvraSR strain compared with Mu3. In summary, VraSR promotes the survival of S. aureus in the host, which may be associated with an increase in the thickness of the cell wall, adhesion, and biofilm formation.

Persistencia de un clon ST6 de Enterococcus faecalis con genotipo vanB2 en dos hospitales de Aragón / Persistence of a ST6 clone of Enterococcus faecalis genotype vanB2 in two Hospitals in Aragon (Spain)

Introducción: Con el objetivo de estudiar la evolución del brote por Enterococcus faecalis ST6 genotipo vanB2 descrito en 2009-2010 en 3 hospitales de Zaragoza, se caracterizaron todos los aislados clínicos E.faecalis resistentes a vancomicina obtenidos entre 2011 y 2013 en dichos hospitales. Métodos: Caracterización molecular de los aislados y estudio de su relación clonal por electroforesis en campos pulsados. Revisión de las historias clínicas de los pacientes. Resultados: Se detectaron 79 aislados E.faecalis genotipo vanB2 de 73 pacientes de 2 de los 3 hospitales analizados, la mayoría de origen urinario. El 46,5% de los casos fueron nosocomiales. La distribución según servicios hospitalarios mostró gran variabilidad, no pudiéndose identificar una fuente de infección común. Todas las cepas fueron multirresistentes (vancomicina, eritromicina, tetraciclina, ciprofloxacino, estreptomicina, gentamicina, kanamicina) y pertenecieron al clon ST6. El 93,7% eran indistinguibles al clon del inicio del brote o subtipos estrechamente relacionados. Conclusión: El brote se mantiene constante en los 3 años posteriores a su descripción, lo que señala la necesidad de mantener un control activo que limite la emergencia y diseminación de clones resistentes a vancomicina (AU)

Introduction: In order to study the evolution of the outbreak that occurred between 2009 and 2010 in 3 hospitals in Zaragoza, all vancomycin-resistant clinical Enterococcus faecalis isolates identified between 2011 and 2013 at these hospitals were characterised. Methods: Molecular characterisation of the isolates and analysis of their clonal relationships was performed using pulsed field electrophoresis, along with a retrospective review of the patient records. Results: A total of 79 vancomycin-resistant E.faecalis isolates with genotype vanB2 of 73 patients were recovered in 2 of the 3 hospitals, most of them from urine specimens. About 46% of the cases were nosocomial. Distribution of the isolates among hospital services demonstrated high variability, making it difficult to predict a common source of infection. All the strains were multiresistant (vancomycin, erythromycin, tetracycline, ciprofloxacin, streptomycin, gentamicin, kanamycin) and belonged to lineage ST6. Seventy-four isolates (93.7%) were identical or closely related to the dominant one in the origin of the outbreak. Conclusion: The outbreak remains constant over three years after being initially described, indicating the need to implement an active control in order to limit the emergence and spread of vancomycin-resistant clones (AU)

Vancomycin heteroresistant community associated methicillin-resistant Staphylococcus aureus ST72-SCCmecIVa strain colonizing the nostrils of a five-year-old Spanish girl / Cepa de Staphylococcus aureus ST72-SCCmecIVa comunitaria, resistente a meticilina y heterorresistente a vancomicina, colonizadora de las fosas nasales de una niña española de 5 años de edad

BACKGROUND AND OBJECTIVES: During a community methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization study, an MRSA strain with vancomycin hetero-resistance (h-VISA) was isolated from a five year-old girl with tetralogy of Fallot without previous exposure to vancomycin. An extended nasal colonization study was performed on all her close relatives. RESULTS: Only the patient and her sister were colonized by an h-VISA MRSA strain (clone USA 700, ST72, t148, agr 1 and SCCmec IVa). Mupirocin decolonisation was effective in the elder sister. A new nasal decolonisation in the younger girl using fusidic acid was also successful. However, after decolonisation both sisters were colonized by a methicillin-susceptible S. aureus (ST30, t012 and agr 3) previously isolated from their mother's nostrils. CONCLUSION: As S. aureus have a great capacity to spread among people in close contact, knowledge of a patients' colonization status, tracing contacts, and a correct management are critical issues for the successful containment of multiresistant staphylococcio

FUNDAMENTO Y OBJETIVO: Durante un estudio comunitario de colonización nasal, hemos aislado Staphylococcus aureus resistente a la meticilina (SARM) con heterorresistencia a vancomicina (hVISA) en una niña de 5 años, que padecía una tetralogía de Fallot, que no había sido tratada previamente con vancomicina. RESULTADOS: Este hallazgo nos llevó a extender el estudio de colonización a sus familiares más cercanos. De estos, solo su hermana mayor fue colonizada por esta cepa SARM hVISA (clon USA 700, ST72, t148, agr 1 y SCCmecIVa). La descolonización con mupirocina fue eficaz en el caso de la hermana, pero un tratamiento con ácido fusídico fue necesario para eliminar la colonización nasal de la paciente. Sin embargo, después de la descolonización, ambas hermanas fueron colonizadas por una cepa de S. aureus sensible a meticilina (ST30, t012 y agr 3), que previamente había sido aislada de las fosas nasales de su madre. CONCLUSIÓN: S. aureus tiene una gran capacidad de diseminación entre personas en estrecho contacto, por lo que el conocimiento del estado de colonización de los pacientes, la evaluación de la colonización nasal de los contactos y una aproximación terapéutica correcta son esenciales para la contención de la diseminación de cepas de estafilococos multirresistentes

Methicillin-Susceptible, Vancomycin-Resistant Staphylococcus aureus, Brazil.

We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate of Staphylococcus aureus recovered from a patient in Brazil. Emergence of vancomycin resistance in methicillin-susceptible S. aureus would indicate that this resistance trait might be poised to disseminate more rapidly among S. aureus and represents a major public health threat.

Absence of intestinal colonization by vancomycin-resistant enterococci in nonhuman primate / Ausência de enterococos resistentes à vancomicina na microbiota intestinal de primatas não-humanos

The animal reservoirs of vancomycin-resistant enterococci (VRE) have important role in the epidemiology of the bacteria and resistant genes. The present work searched fecal samples taken off nonhuman primates for the presence of VRE. Resistance profiles, virulence traits, and genetic variability among enterococci isolates were also analyzed. The samples included Capuchin monkeys (Cebus apella, n=28) and Common marmoset (Callithrix penicillata, n=37) housed in the Primate Center of the University of Brasília, Brazil. Most individuals were captive monkeys from the Central-West and South-East regions of Brazil (n=48). We collected rectal swabs and carried out selective isolation followed by multiplex Polymerase Chain Reaction (PCR) to identify species and resistance genes. No vanA or vanB-containing enterococci were found. The carriage rates ranged from 1.5 percent for the VanC-type E. casseliflavus and E. gallinarum until 12.3 percent (n=8) for Enterococcus faecalis. All E. faecalis isolates showed susceptibility to vancomycin, teicoplanin, ampicillin, gentamicin, and streptomycin. The virulence genes ace and esp were prevalent (100.0 percent, 87.5 percent). Multilocus variable number of tandem repeats (MLVA) revealed diversity in the number of repeats among E. faecalis isolates and targets, which was higher for espC, efa5, and efa6. We identified six different MLVA genotypes that were divergent from those described in human beings. Also, they were clustered into two genogroups that showed host-specificity for the species Cebus apella or Callithrix penicillata. In conclusion, no vanA- or vanB-containing enterococci were found colonizing those primate individuals. This finding suggested that the primate individuals investigated in our study are not directly involved in the epidemiological chain of high-level vancomycin-resistant genes vanA or vanB in Brazil. Our study also showed that E. faecalis isolated from nonhuman primates carry virulence...

Os reservatórios animais de Enterococos Resistentes à Vancomicina (VRE) têm um importante papel na epidemiologia destas bactérias e dos respectivos genes de resistência. O presente estudo examinou a presença de VRE em amostras fecais obtidas de primatas não-humanos. Foram analisados os perfis de resistência, as características de virulência e a variabilidade genética dos isolados. A amostragem incluiu macacos Prego (Cebus apella, n=28) e Sagüis do cerrado (Callithrix penicillata, n=37) alojados no Centro de Primatologia da Universidade de Brasília, Brasil. A maioria dos indivíduos amostrados foram macacos apreendidos na região Centro-Oeste e Sudeste do Brasil (n=48). Assim, foram coletados swabs retais e realizado o isolamento seletivo, seguido da Reação de Polimerização em Cadeia (PCR) multiplex para identificar espécies e genes de resistência. Não foram isolados enterococos contendo os genes vanA ou vanB. A porcentagem de enterococos variou de 1,5 por cento para E. casseliflavus e E. gallinarum VanC até 12,3 por cento (n=8) para Enterococcus faecalis. A totalidade dos isolados da espécie E. faecalis demonstrou sensibilidade aos antimicrobianos vancomicina, teicoplanina, ampicilina, gentamicina e estreptomicina. Os genes de virulência ace e esp foram prevalentes (100 por cento, 87.5 por cento). A análise em multilocus de repetições em tandem de número variável (MLVA) revelou diversidade no número de repetições entre os isolados de E. faecalis, que foi mais alta para espC, efa5 e efa6. Foram identificados seis diferentes genotipos de MVLA, divergindo daqueles já descritos em humanos. Os genotipos foram ainda agrupados em dois genogrupos, demonstrando especificidade de hospedeiro para as espécies Cebus apella ou Callithrix penicillata. Concluindo, não foram isoladas linhagens de enterococos contendo os genes vanA ou vanB colonizando as espécies de primatas analisadas. O presente estudo demonstrou que os isolados de E. faecalis obtidos...

Bacterial flagellin stimulates Toll-like receptor 5-dependent defense against vancomycin-resistant Enterococcus infection.

Treatment of vancomycin-resistant Enterococcus (VRE) infections is limited by the paucity of effective antibiotics. Administration of broad-spectrum antibiotics promotes VRE colonization by down-regulating homeostatic innate immune defenses. Intestinal epithelial cells and Paneth cells express antimicrobial factors on direct or indirect stimulation of the Toll-like receptor (TLR)-myeloid differentiation factor 88-mediated pathway by microbe-derived molecules. Here, we demonstrate that the TLR5 agonist flagellin restores antibiotic-impaired innate immune defenses and restricts colonization with VRE. Flagellin stimulates the expression of RegIIIgamma, a secreted C-type lectin that kills gram-positive bacteria, including VRE. Systemic administration of flagellin induces RegIIIgamma expression in intestinal epithelial cells and Paneth cells along the entire length of the small intestine. Induction of RegIIIgamma requires TLR5 expression in hematopoietic cells and is dependent on interleukin 22 expression. Systemic administration of flagellin to antibiotic-treated mice dramatically reduces VRE colonization. By enhancing mucosal resistance to multidrug-resistant organisms, flagellin administration may provide a clinically useful approach to prevent infections in patients treated with broad-spectrum antibiotics.

Osteomyelitis attributable to vancomycin-resistant enterococci.

Vancomycin-resistant enterococcus first was described in 1988, and has become a major problem in nosocomial infections. This is a retrospective review of 10 patients, seen at the authors' hospital during a 2-year period, with confirmed vancomycin-resistant enterococcal osteomyelitis: four patients had total joint arthroplasty infections, one patient had an infected tibial nail, three patients had infections associated with external fixators, and two patients had osteomyelitis of the femur. Four of the 10 patients had underlying medical illnesses (diabetes mellitus, systemic lupus erythematosus, human immunodeficiency virus infection); four of the 10 patients were intravenous drug users. Two patients had vancomycin-resistant enterococci on admission, and the other eight patients were admitted to the hospital for a mean of 21.3 days (range, 3-73 days) before vancomycin-resistant enterococci were identified in the bone. Eight of the 10 patients had monomicrobial infections with vancomycin-resistant enterococci. Patients were treated by surgical debridement, removal of hardware, and antibiotics (chloramphenicol in eight patients, quinupristin and dalfopristin (Synercid) in two patients). All patients initially improved with therapy, but one patient had a recurrence of vancomycin-resistant enterococcal osteomyelitis and died of bacteremia. Bone infections with vancomycin-resistant enterococcus still may be uncommon, but with time and selective antibiotic pressures, vancomycin-resistant enterococci may become a more prominent entity in orthopaedic infections.

Caracterização de cepas de Staphylococcus aureus resistentes à vancomicina isoladas no Brasil / Staphylococcus aureus strains resistant to vancomycin characterization isolated in Brazil

O isolamento de cepas de Staphylococcus aureus resistente à vancomicina (VRSA) de amostras clínicas foi rekatado no Japão, França, Estados Unidos e Coréia, mas ainda não havia sido relatado no Brasil. O objetivo deste estudo foi avaliar a possível presença de cepas hetero-VRSA ou VRSA em 05 hospitais públicos da cidade de São Paulo. No total, foram triadas 469 cepas de S aureus resistentes à oxacilina (ORSA), das quais 198 foram isoladas no Hospital Geral de Vila Penteado (HGVP), 137 no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), 50 no Hospital AC Camargo, 48 no Hospital Emílio Ribas e 36 no Hospital Universitário da USP. A triagem das cepas hetero-VRSA e VRSA foi realizada...

Prophylactic and therapeutic efficacy of antibodies to a capsular polysaccharide shared among vancomycin-sensitive and -resistant enterococci.

Enterococci are important nosocomial pathogens that are increasingly difficult to treat due to intrinsic and acquired resistance to antibiotics, including vancomycin. A recently described capsular polysaccharide (CP) isolated from Enterococcus faecalis 12030 was used to evaluate the potential efficacy of active or passive immunotherapy regimens as adjunctive treatments. Evaluation of protective efficacy was carried out in immunocompetent mice challenged intravenously (i.v.) with live enterococci. In nonimmune mice, i.v. inoculations resulted in high levels of bacteria in kidneys, spleens, and livers 5 days after challenge. Mice immunized with four 10-microg doses of CP antigen/mouse were protected against challenge with the homologous E. faecalis strain. High-titer opsonic immunoglobulin G was also induced by immunizing rabbits with the purified CP, and passive transfer of this antiserum to mice produced significantly lower bacterial counts in organs than did normal rabbit serum or sterile saline. Antibodies to the polysaccharide isolated from E. faecalis 12030 were protective against Enterococcus faecalis OG1RF and against two serologically related, vancomycin-resistant Enterococcus faecium clinical isolates. Antibodies to this CP antigen were also effective as a therapeutic reagent in mice when passive therapy was initiated 48 h after live bacterial challenge. These data indicate that CP antigens from enterococci are potential targets of protective antibodies and that these antibodies may be useful for prophylaxis and treatment of enterococcal infections.

Comparación de cuatro métodos para la detección de la resistencia a la vancomicina por el enterococo / Comparison of four methods for detection of resistance to vancomycin by enterococcus

Se evaluaron en forma prospectiva 108 cepas de enterococos (83 E. faecalis, 16 E. faecium, 5 E. avium y 4 E. gallinarum) aisladas de diversas muestras clínicas en la sección de Bacteriología del Laboratorio Metropolitano en el período comprendido entre enero y julio de 1999 con la finalidad de comparar cuatro de los métodos descritos para la detección de resistencia a vancomicina in vitro en este grupo de gérmenes: difusión en disco (DD), E test (AB Biodisk, Solina, Sweden), el sistema automatizado Vitek a través de la tarjeta GPS-102 (bioMérieux, Inc., Hazelwood, Mo.), tomando como referencia el agar cerebro-corazón con 6 µ/ml de vancomicina (VSA), observándose una correlación del 93,56 por ciento, 100 por ciento y 97,52 por ciento respectivamente. Se recomienda el uso en paralelo de cualquiera de los métodos en conjunto de la VSA para la segura detección de cepas de enterococcos con sensibilidad disminuida a la vancomicina.