Phenotypic and molecular characterization of Staphylococcus aureus isolates conducted in nares of psoriatic patients attending a public hospital in Argentina / Caracterización fenotípica y molecular de aislamientos de Staphylococcus aureus portados en narinas de pacientes con psoriasis que concurren a un hospital público en Argentina

Abstract Although Staphylococcus aureus increases its relative abundance in psoriasis when compared with the microbiome of healthy subjects, it is not the most important microorganism underlying this disease. However, there is scant data on the role and molecular features of S. aureus strains in psoriasis; therefore, the aim of this study was to evaluate nasal carriage of this microorganism, its phenotypic and molecular characteristics as well as the impact of host factors on its carriage in psoriatic patients. The presence of S. aureus was analyzed in nasal swabs from 46 healthy volunteers and 50 psoriatic patients by conventional microbiology techniques. Nasal carriage of S. aureus was higher in psoriatic patients than in the control group (37.24% vs 22.98%, respectively), being associated to sex (male), age (adults) and severity of the disease (more frequent in moderate and severe cases). Determination of antibiotic resistance detected 12% of (-lactam resistant isolates, with variable accompanying resistance to macrolides, aminoglycosides and fluoroquinolones. No resistance to rifampicin, vancomycin, mupirocin or trimethoprim/sulfamethoxazole was found. A preliminary molecular characterization of the isolates was performed by PCR amplification of virulence genes. Molecular characterization of the strains did not reveal a predominant strain in psoriatic patients. Although we established host factors related to increased carriage of S. aureus in psoriatic patients, we could not establish the predominance of one type of strain. Genomic and transcriptomic analysis of the isolated strains would be necessary to address this point.

Resumen A pesar de que Staphylococcus aureus incrementa su abundancia relativa en la psoriasis cuando se compara con el microbioma de personas sanas, no es el microorganismo más importante subyacente a la enfermedad. Sin embargo, existen pocos datos sobre el papel y las características moleculares de las cepas de S. aureus en pacientes con psoriasis. Nuestro objetivo fue evaluar la portación nasal de este microorganismo, sus características fenotípicas y moleculares, y el impacto de factores del hospedador sobre dicha portación en estos pacientes. Se analizó la presencia de S. aureus en hisopados nasales de 46 voluntarios sanos y 50 pacientes con psoriasis mediante técnicas microbiológicas convencionales. Se encontró mayor portación en pacientes con psoriasis que en el grupo control (37,24% vs. 22,98%, respectivamente) y esta estuvo asociada al sexo (masculino), la edad (adultos) y la gravedad de la enfermedad (más frecuente en casos moderados a graves). El 12% de los aislamientos de S. aureus mostraron resistencia a betalactámicos, con resistencia acompañante a macrólidos, aminoglucósidos y fluoroquinolonas en grado variable. No se encontró resistencia a rifampicina, vancomicina, mupirocina o trimetroprima/sulfametoxazol. Se realizó una caracterización molecular preliminar de los aislamientos por amplificación de genes de virulencia mediante PCR. Si bien se identificaron factores relacionados con el hospedador que incrementan la portación nasal de S. aureus en pacientes con psoriasis, la caracterización molecular de las cepas no reveló ninguna característica genotípica predominante asociada a esta afección. Se necesitan más estudios genómicos y transcriptómicos para profundizar en esta caracterización.

Prevalence and Susceptibility of Staphylococcus aureus Nasal Carriage Strains Isolated from Haemodialysis Patients

@#Introduction: Staphylococcus aureus is part of the normal human flora that can commonly be found on the skin and mucous membranes of the nasal area. However, in immunosuppressed patients such as those with kidney failures, colonization can potentially lead to infection. There is a concern of increasing antibiotic resistance in S. aureus. This study aimed to determine the prevalence of S. aureus nasal colonization and its antimicrobial susceptibility among haemodialysis-dependent populations. Methods: A cross-sectional study at the Nephrology Unit, Hospital Canselori Tuanku Mukhriz (HCTM) was conducted among haemodialysis-dependent patients between February 2017 to February 2018. Nasal swabs were obtained and cultured on mannitol salt agar. S. aureus isolates were identified by gram staining, tube coagulase and Deoxyribonuclease (DNase). Cefoxitin disc (30 µg) were used to identified the presence of MRSA (methicillin-resistance S. aureus). The S. aureus colonies were further tested against six antibiotics using Kirby Bauer disc diffusion. Result: A total of 134 patients were recruited. S. aureus isolates were detected from 27 patients (20.1%). All S. aureus were phenotypically identified as methicillin-sensitive S. aureus (MSSA) based on the cefoxitin disc. Teicoplanin and linezolid were the most effective with 100% susceptibility. S. aureus exhibited a high resistance rate towards erythromycin (29.6%). No MRSA was isolated in this study. Conclusion: This study highlighted the high prevalence of S. aureus nasal colonization in haemodialysis patients. Teicoplanin and linezolid were found to be the most effective antibiotics against isolated S. aureus.

Portación nasal de Staphylococcus aureus en el personal de salud de áreas críticas de un Hospital Pediátrico durante julio-setiembre 2018 / Nasal carriage of Staphylococcus aureus in health personnel in critical areas of a Pediatric Hospital during July-September 2018 / Transporte nasal de Staphylococcus aureus em profissionais de saúde em áreas críticas de um Hospital Pediátrico durante julho-setembro de 2018

Las infecciones intrahospitalarias (IIH) son causa de elevada morbimortalidad y representan un problema sanitario importante. El personal de salud es reservorio y potencial transmisor de los agentes etiológicos de las mismas. S. aureus es uno de los microorganismos implicados, por lo tanto es importante conocer la frecuencia de portación en el personal de salud y establecer el perfil de susceptibilidad antimicrobiana para contribuir con la elaboración de medidas de prevención incluyendo actividades educativas. Objetivo: Conocer la frecuencia de portación de S. aureus, distribución y antibiotipos de las cepas presentes en el personal sanitario del Hospital Pediátrico de Referencia (HPR). Materiales y métodos: Se realizó un estudio descriptivo durante el periodo julio-setiembre del año 2018. Se incluyeron muestras de hisopados nasales de trabajadores de la salud de distintas áreas de internación que consintieron participar en el estudio. Se excluyeron aquellos que recibieron antibióticos dentro de los 3 meses previos al estudio. Las muestras fueron sembradas en agar sangre ovina al 5% (ASO) y se incubaron a 35-37ºC en aerobiosis por 24-48 horas. La identificación de las colonias sospechosas de Staphylococcus aureus por métodos convencionales y MALDI-TOF. El patrón de resistencia antimicrobiana de S. aureus se detectó por disco-difusión. En los cultivos resistentes a meticilina (SAMR) se determinó la presencia del gen mecA y se realizó la tipificación del SCCmec por pruebas de reacción en cadena de polimerasa. Resultados: Se obtuvieron 225 hisopados a partir de 225 trabajadores, presentaron desarrollo 212. En 49 se recuperaron cultivos de S. aureus. Correspondieron a SAMR 11 de las 49 cepas, todas portaban el gen mecA. Hubo predominio en el personal de enfermería (7/11), en los servicios de hemato-oncología (3/11) y cuidados intensivos neonatales (4/11). Asociaron resistencia a macrólidos y clindamicina 8 de 11 aislamientos SAMR, a gentamicina 2 y a mupirocina uno. El SCCmec más frecuentemente identificado fue el tipo IV (7/11). Conclusiones: Los resultados muestran la presencia de cepas SAMR entre el personal de salud del CHPR y aportan información complementaria para efectuar prevención y control de las IIH, actuando sobre todo en el personal de salud encargado de la atención de pacientes susceptibles.

Hospital-acquired infections (IIH) are a cause of high morbidity and mortality and represent a major health problem. Health personnel are reservoirs and potential transmitters of their etiological agents. S. aureus is one of the microorganisms involved, therefore it is important to know the frequency of carriage in health personnel and establish the antimicrobial susceptibility profile to contribute to the development of prevention measures, including educational activities. Objective: To know the frequency of carriage of S. aureus, distribution and antibiotypes of the strains present in the health personnel of the Reference Pediatric Hospital (HPR). Materials and methods: A descriptive study was carried out during the period July-September 2018. Nasal swab samples from health workers from different hospitalization areas who agreed to participate in the study were included. Those who received antibiotics within 3 months prior to the study were excluded. The samples were seeded in 5% sheep blood agar (ASO) and incubated at 35-37ºC in aerobiosis for 24-48 hours. Identification of suspicious Staphylococcus aureus colonies by conventional methods and MALDI-TOF. The antimicrobial resistance pattern of S. aureus was detected by disc diffusion. In methicillin-resistant cultures (MRSA), the presence of the mecA gene was determined and SCCmec was typified by polymerase chain reaction tests. Results: 225 swabs were obtained from 225 workers, 212 showed development. S. aureus cultures were recovered from 49. 11 of the 49 strains corresponded to MRSA, all of them carried the mecA gene. There was a predominance in the nursing staff (7/11), in the hematology-oncology services (3/11) and neonatal intensive care (4/11). They associated resistance to macrolides and clindamycin in 8 of 11 MRSA isolates, 2 to gentamicin, and 1 to mupirocin. The most frequently identified SCCmec was type IV (7/11). Conclusions: The results show the presence of MRSA strains among the health personnel of the CHPR and provide complementary information to carry out prevention and control of IIH, acting especially on the health personnel in charge of the care of susceptible patients.

As infecções hospitalares (HII) são causa de alta morbidade e mortalidade e representam um importante problema de saúde. Os profissionais de saúde são reservatórios e potenciais transmissores de seus agentes etiológicos. O S. aureus é um dos micro-organismos envolvidos, por isso é importante conhecer a frequência de portadores em profissionais de saúde e estabelecer o perfil de suscetibilidade antimicrobiana para contribuir no desenvolvimento de medidas de prevenção incluindo atividades educativas. Objetivo: Conhecer a frequência de portadores de S. aureus, distribuição e antibiótipos das cepas presentes no pessoal de saúde do Hospital Pediátrico de Referência (HPR). Materiais e métodos: Foi realizado um estudo descritivo durante o período de julho a setembro de 2018. Foram incluídas amostras de swab nasal de profissionais de saúde de diferentes áreas de internação que concordaram em participar do estudo. Aqueles que receberam antibióticos nos 3 meses anteriores ao estudo foram excluídos. As amostras foram semeadas em 5% de ágar sangue de carneiro (ASO) e incubadas a 35-37ºC em aerobiose por 24-48 horas. Identificação de colônias suspeitas de Staphylococcus aureus por métodos convencionais e MALDI-TOF. O padrão de resistência antimicrobiana de S. aureus foi detectado por difusão em disco. Em culturas resistentes à meticilina (MRSA), a presença do gene mecA foi determinada e SCCmec foi tipificado por testes de reação em cadeia da polimerase. Resultados: 225 swabs foram obtidos de 225 trabalhadores, 212 apresentaram desenvolvimento. Culturas de S. aureus foram recuperadas de 49. 11 das 49 cepas correspondiam a MRSA, todas carregavam o gene mecA. Houve predominância na equipe de enfermagem (7/11), nos serviços de hematologia-oncologia (3/11) e de terapia intensiva neonatal (4/11). Eles associaram resistência a macrolídeos e clindamicina em 8 de 11 isolados de MRSA, 2 à gentamicina e 1 à mupirocina. O SCCmec mais frequentemente identificado foi o tipo IV (7/11). Conclusões: Os resultados mostram a presença de cepas de MRSA entre os profissionais de saúde do CHPR e fornecem informações complementares para realizar a prevenção e controle da HII, atuando principalmente sobre os profissionais de saúde responsáveis ​​pelo atendimento de pacientes suscetíveis.

Portación nasal de Staphylococcus aureus en trabajadores de la salud de dos hospitales de la ciudad de Bahía Blanca, Argentina / Staphylococcus aureus nasal carriage in health care workers at two hospitals in Bahía Blanca city, Argentina / Carreamento nasal de Staphylococcus aureus em profissionais da saúde de dois hospitais da cidade de Bahía Blanca, Argentina

Resumen La portación nasal de Staphylococcus aureus representa un riesgo considerable para infecciones tanto nosocomiales como comunitarias. El objetivo del trabajo fue investigar la prevalencia de portación nasal de S. aureus sensibles (SAMS) y resistentes a meticilina (SAMR) en trabajadores de la salud, determinar su asociación con factores epidemiológicos y sus patrones de resistencia a los antimicrobianos. Se tomaron 152 muestras nasales de personal de dos hospitales de la ciudad de Bahía Blanca (Argentina). Los aislados de S. aureus se identificaron por métodos convencionales y por el sistema automatizado BD PhoenixTM 100. La prevalencia de portación nasal de S. aureus fue de 32,2% y, de SAMR, de 12,2%. La frecuencia de portación en el personal de laboratorio (58,8%) resultó estadísticamente significativa. Los aislados fueron sensibles a trimetoprima-sulfametoxazol, cloranfenicol, rifampicina, fluoroquinolonas y vancomicina. Estos datos alertan sobre la necesidad de identificar portadores de S. aureus e implementar estrategias que controlen una potencial diseminación de estos microorganismos.

Abstract The nasal carriage of Staphylococcus aureus represents a considerable risk for both nosocomial and community infections. The objective of this work was to investigate the prevalence of nasal carriage of both methicilin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) in health workers, to determine their association with epidemiological factors and their patterns of antimicrobial resistance. One hundred and fifty-two nasal samples were taken from personnel from two hospitals in the Bahía Blanca city (Argentina). The S. aureus isolates were identified by conventional methods and by the automated BD PhoenixTM 100 system. The prevalence of S. aureus nasal carriage was 32.2% and that of MRSA, 12.2%. The frequency of carrying deterin laboratory personnel was statistically significant (58.8%). The isolates were susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, rifampin, fluoroquinolones and vancomycin. These data warn of the need to identify S. aureus carriers and implement strategies that control the potential spread of these microorganisms.

Resumo O carreamento nasal de Staphylococcus aureus representa um risco considerável para infecções tanto nosocomiais quanto comunitárias. O objetivo do trabalho foi investigar a prevalência de carreamento nasal de S. aureus sensíveis (SAMS) e resistentes à meticilina (SARM) em profissionais da saúde; determinar sua associação com fatores epidemiológicos e seus padrões de resistência aos antimicrobianos. Foram coletadas 152 amostras nasais de funcionários de dois hospitais da cidade de Bahía Blanca (Argentina). Os isolados de S. aureus foram identificados por métodos convencionais e pelo sistema automatizado BD PhoenixTM 100. A prevalência de carreamento nasal de S. aureus foi de 32,2% e a de SARM, de 12,2%. A frequência de carreamento no pessoal do laboratório foi estatisticamente significativa (58,8%). Os isolados foram sensíveis a trimetoprim-sulfametoxazol, cloranfenicol, rifampicina, fluoroquinolonas e vancomicina. Esses dados alertam para a necessidade de identificar portadores de S. aureus e implementar estratégias que controlem a propagação potencial desses microrganismos.

Assessment of Pathogenicity of Community-Acquired MRSA Isolates in Mice-Induced Peritonitis

@#Introduction: Methicillin-Resistance Staphylococcus aureus (MRSA) is known as a major nosocomial pathogen in healthcare. However, it has now spread in the community known as community-acquired MRSA (CA-MRSA). Thus, the survival and pathogenicity of CA-MRSA isolates were assessed using in vivo peritonitis model with comparison to ATCC-MRSA. Two CA-MRSA isolates; CA-MRSA1 and CA-MRSA2 that were isolated from healthy population, were studied and compared. Methods: Mice were assigned into 4 groups and injected intraperitoneally with ATCC-MRSA, CA-MRSA1 or CA-MRSA2, respectively. Sterile Dulbecco’s Phosphate-Buffered Saline (DPBS) represents negative control. Mice were observed twice daily, 0-72 hours of post-infection. Any signs of distress were recorded for severity score and survival analyses. Mice were euthanised at 72 hours post-inoculation or by referring to the Peritonitis Severity Scoring (PSS) system. Organs of interest, peritoneal lavage and abscess were processed for bacterial counts. Tissue samples were analysed for histopathological scores. Results: All mice inoculated with MRSA showed clear signs of illness with peritonitis symptoms of p<0.001 and comparable PSS scores were recorded in all infected mice groups. Intraperitoneal injection of lethal dose of MRSA resulted in significant death of ATCC-MRSA (p<0.05) and CA-MRSA-infected mice (p<0.01), compared to the un-infected. Bacterial burden was significantly high in all samples harvested from mice challenged with CA-MRSA2 compared to ATCC-MRSA except in abscess and lung. Significant liver necrosis and spleen inflammation were observed in CA-MRSA1, and lung inflammation in ATCC-MRSA-infected mice. Conclusion: Nasal carriage CA-MRSA isolates from a healthy population has the potential to cause peritonitis with comparable severity as ATCC-MRSA.

Resistance pattern of methicillin resistant Staphylococcus aureus among nasal isolates of HIV infected patients in a tertiary care hospital

Background: Patients infected with HIV have an increased risk of nasal Staphylococcus aureus carriage as well as consecutive staphylococcal infections and is a major reservoir for MRSA which is potential risk factors for community acquired MRSA. Knowing the Nasal carriage status of Staphylococcus aureus and their Antibiogram will be beneficial for effective management of these patients.Methods: Nasal swab sample were collected from all the participants and processed for culture and identification of Staphylococcus aureus and their antimicrobial sensitivity. All the Staphylococcus aureus isolates were tested for Methicillin resistance by Oxacillin screen agar test, cefoxitin disc diffusion test and further confirmed by mecA gene PCR.Results: In this study out of 220 HIV seropositive patients, 43.64% isolates were confirmed to be S. aureus, 18.75% MRSA and 81.25% were MSSA. Cefoxitin disc diffusion showed 100% specificity (95% CI; 97.05%-100.00%), 100% sensitivity (95% CI; 83.89-100.00%) and 100% accuracy (95% CI; 97.47% to 100.00%) while comparing with gold standard mecA gene PCR. Among the nasal carriers; males (60%) ware dominant on females (40%). 31-50 years age group was strongly associated with MRSA nasal carriage. None of the isolates were resistant against lenozolid, teicoplanin and vancomycin while ampicillin (75%), ciprofloxacin (62.5%), clindamycin (59.38%) and cotrimoxazole (53.13%) showed increased resistance against S. aureus nasal carriage.Conclusions: Resistance among HIV positive persons for all antibiotics showed statistically significant while compared to control group. Cefoxitin disc diffusion can be used as surrogate agent for mecA gene detection.

Portación Nasal de Staphylococcus aureus y su Asociación con Forunculosis a Repetición

Resumen Staphylococcus aureus es una bacteria que coloniza la piel y/o fosas nasales de las personas sanas y produce una amplia gama de infecciones, desde forúnculos hasta las más graves como neumonía o sepsis. La portación nasal de S.aureus parece ser clave en la epidemiologia y la patogenia de la infección. S. aureus se caracteriza por presentar el gen mecA que confiere resistencia a meticilina pudiendo ser sensible a otros antibióticos no betalactámicos. Su virulencia se asocia principalmente a la toxina Leucocidina de Panton Valentine (PVL) una citotoxina que provoca destrucción de los leucocitos y necrosis tisular, lo que a su vez facilita la producción de abscesos. Los objetivos de este estudio fueron, asociar la portación nasal de S. aureus con la forunculosis a repetición, determinar por el método de reacción en cadena de la polimerasa (PCR) los genes que codifican la meticilino resistencia y la toxina PVL. Se estudiaron 128 cepas de S. aureus provenientes de pacientes que estuvieron con o sin tratamiento con antibióticos, y que concurrieron al laboratorio entre 2016 y 2017 con diagnóstico de forunculosis a repetición, de las cuales 74 cepas se aislaron de las lesiones y 54 de sus hisopados nasales. Del total de cepas, se obtuvieron 66,4% de meticilino resistencia y 78,9% presentaron la toxina PVL. Se obtuvo una alta asociación entre la portación nasal de S. aureus de la comunidad con forunculosis a repetición (OR: 5,3 IC95: 1,9 - 14,2%; p = 0,0004< p=0,02; X2)

Abstract Staphylococcus aureus is a bacterium that colonizes the skin and / or nostrils of healthy people and produces a wide range of infections, from forunculosis to the most serious such as pneumonia or sepsis. The nasal carriage of Staphylococcus aureus appear to be key in the epidemiology and pathogenesis of infection. Staphylococcus aureus characterizes by presenting the mecA gene which confers resistance to methicillin and could be sensitive to other non-beta-lactam antibiotics. Its virulence is mainly associated to the Panton-Valentine Leucocidine (PVL) a cytotoxin that causes destruction of the leukocytes and tissue necrosis, which facilitates the abscess production. The objectives of this study were, to associate the nasal carriage of Staphylococcus aureus with recurrent forunculosis, to determine by the polymerase chain reaction method (PCR) the genes encoding methicillin resistance and the toxin PVL. It was studied 128 strains of Staphylococcus aureus from patients with or without antibiotic treatment and went to the laboratory between 2016 and 2017 with recurrent forunculosis, of which 74 strains were isolated from the lesions and 54 from nasal swabs. Of the total strains, 66.4% were methicillin resistance and 78.9% presented PVL toxin. There obtained a high association between the nasal carriage of Staphylococcus aureus of the community with recurrent forunculosis (OR: 5,3 IC95: 1,9 - 14,2%; p = 0,0004< p=0,02; X2).

Nasal carriage rate of methicillin resistant Staphylococcus aureus among Iranian healthcare workers: a systematic review and meta-analysis

Abstract Globally, methicillin-resistant Staphylococcus aureus (MRSA) remains a major cause of healthcare-associated infections. Healthcare workers (HCWs), patients and the environment may act as reservoirs for the spread of MRSA to patients and other HCWs. Screening and eradication of MRSA colonization is an effective method of reducing the MRSA infection rate. There are limited data on the prevalence of MRSA among Iranian HCWs. We performed a systematic search by using different electronic databases including Medline (via PubMed), Embase, Web of Science, and Iranian Databases (from January 2000 to July 2016). Meta-analysis was performed using the Comprehensive Meta-Analysis (Biostat V2.2) software. The meta-analyses showed that the prevalence of S. aureus and MRSA among HCWs were 22.7% [95% confidence interval (CI): 19.3-26.6] and 32.8% (95% CI: 26.0-40.4) respectively. The high rate of nasal MRSA carriage among Iranian HCWs has been attributed to poor compliance to hand hygiene, injudicious use of antibiotics, and ineffective infection control and prevention measures. The rational use of antibiotics plus strict infection control are the main pillars for controlling multidrug resistant microorganisms such as MRSA in the hospital setting. These measurements should be applied nationally.

Staphylococcus aureus nasal carriage in health care workers: First report from a major public hospital in Argentina / Portación nasal de Staphylococcus aureus en trabajadores de la salud: primer reporte en un hospital público en Argentina

Staphylococcus aureus causes numerous mild to severe infections in humans, both in health facilities and in the community. Patients and health care workers (HCWs) may disseminate strains during regular medical examinations or hospitalization. The aim of this study was to determine the nasal carriage rate of methicillin-susceptible and methicillin-resistant S. aureus among health care workers at Hospital Provincial del Centenario, a public general hospital in Rosario, Argentina. A transversal study was conducted on 320 health care workers. Nasal swabs were taken and presumptive S. aureus colonies were isolated. Bacterial identity and methicillin resistance status were confirmed by amplification of the nuc and mec genes. Chi square test and Fisher exact test were used for statistical analysis. Of 320 HCWs, 96 (30%) were nasal carriers of S. aureus, 20 of whom (6.3%) carried methicillin-resistant S. aureus (MRSA) and 76 (23.7%) methicillin-susceptible S. aureus (MSSA). Carriage was within thepublished values for physicians (30%) and higher for technicians (57%). Accompanying resistance (62/96, 64.6%) was detected, including resistance to fluoroquinolones (23/96, 24%), aminoglucosides (13/96, 13.5%) or to macrolides (33/96, 34.4%). All the strains were susceptible to vancomycin whereas only 3.1% (3/96), all of them on MSSA strains, were resistant to mupirocin. This study is the first one of its kind in Argentina and one of the few performed in South America, to highlight the relevance of nasal carriage of MRSA and MSSA in health care personnel and brings to light the need for consensus recommendations for regular S. aureus carriage screening as well as for decolonization strategies.

Staphylococcus aureus es agente causal de numerosas infecciones en humanos, que pueden ser desde leves hasta graves, y circula tanto en la comunidad como en las instalaciones de los centros de salud. Los pacientes y los trabajadores de la salud pueden diseminar cepas durante los exámenes médicos de rutina o durante la hospitalización. El foco de este estudio fue determinar la tasa de portación nasal de S. aureus sensible o resistente a meticilina en trabajadores de la salud del Hospital Provincial del Centenario, un hospital público de atención primaria en Argentina. Se llevó a cabo un estudio transversal en 320 trabajadores de la salud (TS). Se tomaron hisopados nasales y se aislaron colonias presuntivas de S. aureus. La identidad de las bacterias y su resistencia a meticilina fueron confirmadas por amplificación de los genes nuc y mec. El análisis estadístico comprendió el test de la chi al cuadrado y el test de exactitud de Fisher. De 320 TS, 96 (30%) fueron portadores nasales de S. aureus, de los cuales 20 (6,3% del total) llevaban cepas de S. aureus resistentes a meticilina (SARM) y 76 (23,7% del total) eran portadores de cepas sensibles a meticilina (SASM). La portación entre los médicos fue del 30% y estuvo dentro de los niveles publicados; dentro del subgrupo del personal técnico la portación fue superior: 57%. Se detectaron resistencias acompañantes (64,6%; 62/96) a fluoroquinolonas (24%; 23/96), aminoglucósidos (13,5%; 13/96) o macrólidos (34,4%; 33/96). Todas las cepas fueron sensibles a vancomicina y solo el 3,1% (3/96), las 3 SASM, fueron resistentes a mupirocina. Este estudio, el primero en su tipo en Argentina y uno de los pocos hechos en América del Sur, remarca la relevancia de la portación nasal de SARM y SASM en el personal de atención de la salud y evidencia la necesidad de contar con recomendaciones consensuadas para el tamizaje regular de S. aureus, así como de estrategias de descolonización.

Emergence of staphylococcal cassette chromosome mec type Ⅰ with high-level mupirocin resistance among methicillin-resistant Staphylococcus aureus

Objective: To investigate the molecular epidemiology and antimicrobial resistance patterns of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers and patients. Methods: MRSA isolates were recovered from nasal swabs collected at a tertiary care hospital of Nepal and confirmed on the basis of Gram staining, conventional biochemical tests, and PCR amplification of mecA gene. PCRs were also used for detection of the different resistance genes and staphylococcal cassette chromosome (SCC) mec types. Antibiotic susceptibility patterns of isolates were assessed by disc diffusion method and minimum inhibitory concentrations were determined by E-test. Results: A total of 29 MRSA were isolated from 536 nasal swabs (5.4%) of health care workers and patients at a tertiary care hospital in Nepal. All isolates were susceptible to amikacin, gentamicin, vancomycin (minimal inhibitory concentrations1024μg/mL). Fourteen isolates were found harboring the mupA gene and one isolate was found carrying the novel mupB gene. High prevalence (68%) of SCCmec I type was found, followed by SCCmec V (13%) and SCCmec III (3%) among all the MRSA isolates. Conclusions: We found the emergence of SCCmec type Ⅰ with high-level mupirocin resistance among MRSA in Nepal. Data also suggest that MRSA SCCmec type V strain has spread from the community to the hospital.

Emergence of staphylococcal cassette chromosome mec type I with high-level mupirocin resistance among methicillin-resistant Staphylococcus aureus

Objective To investigate the molecular epidemiology and antimicrobial resistance patterns of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers and patients. Methods MRSA isolates were recovered from nasal swabs collected at a tertiary care hospital of Nepal and confirmed on the basis of Gram staining, conventional biochemical tests, and PCR amplification of mecA gene. PCRs were also used for detection of the different resistance genes and staphylococcal cassette chromosome (SCC) mec types. Antibiotic susceptibility patterns of isolates were assessed by disc diffusion method and minimum inhibitory concentrations were determined by E-test. Results A total of 29 MRSA were isolated from 536 nasal swabs (5.4%) of health care workers and patients at a tertiary care hospital in Nepal. All isolates were susceptible to amikacin, gentamicin, vancomycin (minimal inhibitory concentrations  1 024 μg/mL). Fourteen isolates were found harboring the mupA gene and one isolate was found carrying the novel mupB gene. High prevalence (68%) of SCCmec I type was found, followed by SCCmec V (13%) and SCCmec III (3%) among all the MRSA isolates. Conclusions We found the emergence of SCCmec type I with high-level mupirocin resistance among MRSA in Nepal. Data also suggest that MRSA SCCmec type V strain has spread from the community to the hospital.

Nasal carriage and antimicrobial resistance of bacteria in health care workers in an intensive care unit / 中国感染控制杂志

Objective To evaluate nasal carriage and antimicrobial resistance of bacteria in health care workers (HCWs)in an intensive care unit (ICU),and provide basis for making prevention and control measures of health-care-associated infection(HAI).Methods From April 2014 to March 2015,nasal swabs from HCWs in ICU were collected,carriage and antimicrobial resistance of bacteria were detected.Results A total of 450 nasal swab speci-mens were taken,137 strains were isolated,isolation rate was 30.44%.There were no significant difference in na-sal carriage rates of bacteria in HCWs with different genders,ages,types of work,length of service,and education-al level (P >0.05);nasal carriage rates in HCWs at different seasons were significantly different (P <0.05 ).82 strains (59.85%)were gram-negative bacteria,the major were Klebsiella pneumoniae (21 .16%)and Enterobacter aerogenes (18.98%);55 strains (40.15% )were gram-positive bacteria,the major were Staphylococcus aureus (18.98%)and Staphylococcus epidermidis (15.33%).38 (27.74% )strains were multidrug-resistant strains. 7.69% (2/26)of Staphylococcus aureus were methicillin-resistant strains,3.45%(1/29)of Klebsiella pneumoniae and 3.85%(1/26)of Enterobacter aerogenes were imipenem-resistant strains.Conclusion Nasal carriage rate of bac-teria and detection rate of multidrug-resistant organisms in HCWs in ICU is high.

Antimicrobial Resistance and Molecular Characteristics of Nasal Staphylococcus aureus Isolates From Newly Admitted Inpatients

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.

Portadores nasales de S. aureus en el personal de enfermería de un centro de salud del Estado Carabobo, Venezuela / Nasal carriers of S. aureus in the nursing staff of health center from Carabobo state, Venezuela

Staphylococcus aureus ha resultado ser un problema en el área de la salud, por su comportamiento frente a pacientes inmunosuprimidos y por la resistencia bacteriana que ha desarrollado en las últimas décadas. Es común que la fuente de infección sea el personal de salud, por ende el conocimiento de los factores de riesgo y la presencia de patologías alérgicas podría prevenir la colonización nasal del personal de salud y la posterior transmisión a los pacientes hospitalizados. La investigación fue de tipo descriptiva no experimental y de corte transversal, consistió en evaluar la frecuencia de portadores nasales de Staphylococcus aureus en el personal de enfermería de un centro de salud del Estado Carabobo. La muestra estuvo conformada por 30 enfermeras, donde 50% (15) resultaron no portadoras de dicho microorganismo, 27% (8) portadoras SAMS, y 23% (7) portadoras de SAMR, se detectaron 8 patrones de resistencia antibiótica, de donde destaca la resistencia a oxacilina, cefoxitin, clindamicina, eritromicina y ciprofloxacina, se obtuvo asociación estadísticamente significativa (p=0,0001) entre la portación nasal Staphylococcus aureus y la presencia de antecedentes de patologías alérgicas, por lo tanto puede considerarse que la presencia de estas patologías es un factor de riesgo de colonización nasal.

Staphylococcus aureus has been a problem in the area of health, for their behavior in immunosuppressed patients and bacterial resistance has developed in recent decades. It is common that the source of infection be health personnel, hence the knowledge of risk factors and the presence of allergic diseases could prevent nasal colonization of health personnel and subsequent transmission to hospitalized patients. It was a descriptive, not experimental and cross section research to assess the frequency of nasal carriage of Staphylococcus aureus in nursing staff of health center from Carabobo state. The sample consisted of 30 nurses, where 50% (15) were not carriers of this organism, 27% (8) carriers SAMS, and 23% (7) carriers of MRSA, 8 patterns of antibiotic resistance were detected, of which highlights resistance, to oxacillin, cefoxitin, clindamycin, erythromycin, ciprofloxacin, statistically significant association (p = 0.0001) between Staphylococcus aureus nasal carriage and the presence of a history of allergic diseases is obtained, thus can be considered that the presence of these pathologies is a risk factor of nasal colonization.

Widespread nasal carriage of Mycobacterium lepraeamong a healthy population in a hyperendemic region of northeastern Brazil

A case-control study was conducted to determine the presence ofMycobacterium lepraeDNA in nasal secretions of leprosy cases and nonleprosy individuals in Fortaleza, Brazil. It included 185 cases identified by physicians at the Dona Libânia National Reference Centre for Sanitary Dermatology (CDERM). A control group (Co) (n = 136) was identified among individuals from CDERM not diagnosed as leprosy cases. To augment the spatial analysis of M. leprae specific repetitive element (RLEP) positive prevalence, an external group (EG) (n = 121), a convenience sample of healthy students, were included. Polymerase chain reaction for the RLEP sequence was conducted for all participants. Prevalence of RLEP positivity for cases and Co were 69.2% and 66.9%, respectively, significantly higher than for EG (28.1%), and reported elsewhere. Male sex, belonging to a lower socioeconomic status (D/E), history of a previous contact with a case and being older, were associated with being a leprosy case. Our geographical analysis demonstrated that the bacillus is widespread among the healthy population, with clusters of RLEP positive multibacillary cases concentrated in distinct areas of the city. Our results suggest that in endemic areas, as in Fortaleza, surveillance for both nonhousehold leprosy contacts and members of the general population living in cluster areas should be implemented.

Portación nasal de Staphylococcus aureus en niños seropositivos para VIH/SIDA de la Fundación INNOCENS: Resistencia a meticilina y eritromicina / Nasal Carriage of Staphylococcus aureus in HIV/AIDS Positive Children at the Innocens Foundation: Resistance to Methicillin and Erythromycin

Staphylococcus aureus forma parte de la flora normal de piel y mucosas, siendo las fosas nasales su reservorio primario. Los pacientes con VIH/SIDA portadores de S. aureus son más propensos a desarrollar infecciones por este microorganismo. El objetivo fue determinar la portación nasal de S. aureus en niños que acuden a la consulta externa de la Fundación INNOCENS y su resistencia a meticilina y eritromicina, mediante un estudio descriptivo y prospectivo. Durante los meses febrero-abril de 2013 se analizaron 38 muestras de secreción nasal. Las muestras fueron inoculadas en placas de Agar Sangre y las colonias compatibles con Staphylococcus spp. fueron identificadas hasta su especie. A las cepas de S. aureus se les detectó la resistencia a oxacilina mediante la técnica de difusión del disco, Screening test (Agar suplementado con 6 ug/mL de oxacilina y 4% de Cloruro de sodio) y Concentración Inhibitoria Mínima. De los 38 niños con VIH positivo, 17 (44,7%) fueron portadores de S. aureus en sus fosas nasales. De estos, 3 fueron resistentes a meticilina y 8 (47,1%) mostraron resistencia a eritromicina. La portación nasal de S. aureus en los niños portadores de VIH positivo representa un grave problema ya que puede comprometer aún más su salud.

Staphylococcus aureus is part of the normal flora of the skin and mucous membranes, with the nostrils the primary reservoir. Patients with HIV/AIDS, carriers of S. aureus, are more likely to develop infections due to this organism. The aim was to determine the nasal carriage of S. aureus in children who come for outpatient consultation at the INNOCENS Foundation and its resistance to methicillin and erythromycin, using a prospective descriptive study. During the months February-April 2013, 38 nasal secretion samples were analyzed. The samples were inoculated onto blood agar plates and colonies compatible with Staphylococcus spp. were identified, including their species. In the S. aureus strains, resistance to oxacillin was detected by the disk diffusion method, a screening test (agar supplemented with 6 ug/mL of oxacillin and 4% sodium chloride) and Minimum Inhibitory Concentration. Of the 38 children with HIV, 17 (44.7 %) carried S. aureus in their nostrils. Of these, 3 were resistant to methicillin and 8 (47.1%) were resistant to erythromycin. Nasal carriage of S. aureus in children with HIV is a serious problem because it can further compromise their health.

Portación nasal de staphylococcus aureus meticilino resistentes en poblaciones de la comunidad / Nasal colonization with methicillin-resistant staphylococcus aureus in the community

Staphylococcus aureus (SA) causa infecciones graves. Las debidas a cepas resistentes a meticilina representan undesafío terapéutico. Actualmente hay un aumento de casos de infecciones de piel y tejidos blandos con inusitadagravedad debidas a S. aureus meticilinorresistentes adquiridos en la comunidad (SAMR AC) pero se desconoce latasa de colonización de la población sana en nuestro medio. El propósito de este trabajo fue determinar la portación nasal en grupos de deportistas y personas que habitan en residencias de ancianos. Se tomaron hisopados nasales de 332 personas, 180 alojados en 4 residencias de ancianos y 152 de 7 grupos de deportistas, los cuales fueron extraídos, conservados y cultivados por los métodos convencionales. La caracterización molecular fue efectuada por PCR buscando el tipo de cassette cromosómico estafilocócico con el gen mecA (SCCmecA) y el gen que codifica la leucocidina de Panton-Valentine. Se asiló SA en 83 pacientes (25%), de los cuales 40 fueron SA meticilinosensibles (21,1%) y 13 SAMR (3,9%). Ocho casos fueron clasificados fenotípicamente y genotípicamente como SAMR AC (2,4%). Todos tenían SCCmecA tipo IV. Es necesaria una atenta vigilancia ya que las infecciones de piel y tejidos blandos de la comunidad no deberían ser tratadas con antibióticos betalactámicos

Staphylococcus aureus isolates are common causes of skin and soft tissue infections and other invasive infections. Those due to methicillin resistant strains represent a therapeutic challenge. Currently there is an increase in cases due to community-acquired methicillin-resistant S. aureus (CA-MRSA) but the rate of colonization of the healthy population is unknown in our country. The purpose of this study was to determine nasal carriage in sportsmen and people living in nursing homes in Rosario. Nasal swabs of 101 people staying in 4 nursing homes and of 98 from 7 groups of athletes were obtained. The samples were extracted, preserved, and cultured by conventional methods. PCR was performed in order to study the type of staphylococcal chromosome cassette mecA (SCCmecA) gene and the gene encoding the Panton-Valentine leukocidin. S. aureus was isolated in 48 patients (24.1%), of which 40 were methicillin-sensitive S. Aureus (20.1 %), and 8 methicillin resistant S. aureus (4.0%). Five cases were characterized phenotypically and genotypically as CA-MRSA (2.5%). All of them had type IV SCCmecA. Careful surveillance is required because skin and soft tissue infections in the community should not be treated with beta-lactam antibiotics

Nasal carriage of Methicillin‑resistant Staphylococcus aureus among healthy population of Kashmir, India.

Background: Nasal colonisation with community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is being increasingly reported, especially in places where people are in close contact and where hygiene is compromised. The aim of this study was to find out prevalence of methicillin resistant S.aureus (MRSA) colonising anterior nares of healthy subjects. Materials and Methods: Nasal swabs of healthy subjects were collected aseptically and cultured using standard microbiological protocols. Antibiotic susceptibility was done by Kirby-Bauer disc diffusion method according to CLSI guidelines. Methicillin resistance was detected by cefoxitin disc diffusion method and confirmed by minimum inhibitory concentration (MIC) and amplification of mecA gene by PCR. Strain typing of MRSA strains was done by PFGE. Results: Out of 820 samples, S.aureus was isolated from 229 (27.92%) subjects. Of the 229 isolates, 15 were methicillin resistant. All S. aureus isolates were susceptible to vancomycin. Nasal carriage of MRSA was found to be 1.83% among healthy population. The isolates were found to be polyclonal by PFGE analysis. Conclusion: High prevalence of MRSA is a cause of concern and strategies to interrupt transmission should be implemented.

Portación nasal de Staphylococcus aureus en individuos de la comunidad: factores epidemiológicos / Nasal carriage of Staphylococcus aureus in community individuals: epidemiological factors / Carreamento nasal de Staphylococcus aureus em indivíduos da comunidade: fatores epidemiológicos

La portación nasal de Staphylococcus aureus (SAU) en individuos sanos confirma su diseminación, constituye una fuente potencial de infección y se la relaciona con patologías atópicas. El objetivo del trabajo fue determinar la prevalencia de colonización nasal de SAU en individuos de la comunidad, sus respectivos patrones de resistencia antimicrobiana (PRA) y su asociación con factores epidemiológicos. Se realizó un estudio en 150 hisopados nasales. Se identificaron los aislados de SAU por métodos convencionales, y se evaluó su sensibilidad antimicrobiana por el método de difusión con discos de Kirby-Bauer y en cepas de Staphylococcus aureus resistentes a meticilina (SAMR) se confirmó la presencia del gen mec A y se investigó el gen lpv codificante de la toxina de Panton y Valentine (LPV) por PCR. Se analizó su asociación con factores epidemiológicos (lesiones, rinitis, etc.) con el programa SPSS. Se obtuvieron 119 aislamientos de SAU (79%) con 12 PRA. Las PCR de las cepas SAMR fueron positivas para el gen mec A y negativas para el gen lpv. Estadísticamente se detectó asociación de colonización nasal con sexo masculino y rinitis. Se concluye que la prevalencia de portación nasal de SAU en la comunidad fue elevada y mayor en varones. Los aislamientos multirresistentes y SAMR- LPV (-) sugieren relación hospitalaria y su diseminación a la comunidad. Es importante el hallazgo de la asociación epidemiológica con rinitis, la cual confirma vinculación con patologías atópicas.

Nasal carriage of Staphylococcus aureus (SAU) in healthy individuals confirms its spreading, constitutes a potential infection source and is related to atopic pathologies. The objetive was to determine the prevalence of SAU nasal carriage in community individuals, its antimicrobial resistance patterns (ARP) and its association with epidemiological factors. A total of 150 nasal swabs were studied, where SAU isolates were identified by conventional methods and their antimicrobial sensitivity was evaluated by disk diffusion Kirby Bauer test. In addition, the presence of mec A gene was confirmed and the lpv gene coding for Panton-Valentine toxin (PVL) was investigated by PCR in methicillin resistant Staphylococcus aureus (MRSA) strains. Its association with epidemiological factors (injuries, rhinitis, etc) was analyzed with SPSS program. One hundred and nineteen (79%) SAU isolates with 12 ARP were obtained. PCR assays of MRSA strains were positive for the mec A gene and negative for the lpv gene. Association between nasal colonization and both male sex and rhinitis was detected statistically. It can be concluded that high prevalence of SAU nasal carriage was found in the community, mainly in males. Multiresistant isolates and lpv (-) MRSA suggest a hospital-acquired infection with subsequent dissemination to the community. The epidemiological association with rhinitis, which confirms the link with atopic pathologies, deserves to be highlighted.

O carreamento nasal de Staphylococcus aureus (SAU) em individuos saudáveis confirma sua disseminagao, constitui uma fonte potencial de infecgao e é relacionada com patologias atópicas. O objetivo do trabalho foi determinar a prevalencia de colonizagao nasal de SAU em individuos da comunidade, seus respectivos padróes de resistencia antimicrobiana (PRA) e sua associagao com fatores epidemiológicos. Foi realizado um estudo em 150 esfregagos nasais. Identificaramse os isolados de SA U por métodos convencionais, e foi avaliada sua sensibilidade antimicrobiana pelo método de difusao com discos de Kirby-Bauer e em cepas de Staphylococcus aureus resistentes a meticilina (SAMR) foi confirmada a presenga do gene mec A e se investigou o gene lpv codificante da toxina de Panton - Valentine (LPV) por PCR. Foi analisada sua associagao com fatores epidemiológicos (lesóes, rinite, etc.) com o programa SPSS. Obtiveramse 119 isolamentos de SAU (79%) com 12 PRA. As PCR das cepas SAMR foram positivas para o gene mec A e negativas para o gene lpv. Estatisticamente se detectou associagao de colonizagao nasal com sexo masculino e rinite. Concluise que a prevalencia de carreamento nasal de SAU na comunidade foi elevada e maior em homens. Os isolamentos multirresistentes e SAMR- LPV (-) sugerem relagao hospitalar e sua disseminagao para a comunidade. É importante o achado da associagao epidemiológica com rinite, a qual confirma vinculagao com patologias atópicas.

Staphylococcus aureus Nasal Carriers Among Medical Students in A Medical School

Staphylococcus aureus is usually considered a colonizer but can result in infections under favourable conditions, especially in the healthcare setting. Healthcare workers can be colonized by S. aureus, and may transmit them to patients under their care. We conducted a cross sectional study to determine the prevalence of S. aureus nasal carriers among medical students in Universiti Putra Malaysia (UPM) (from January to June 2011). Our study involved 209 medical students comprising of 111 and 97 preclinical and clinical students respectively. A selfadministered questionnaire was distributed and nasal swabs were collected. Upon identification, the antibiotic susceptibility of the isolates was examined followed by categorical analysis (Chi-square and Fisher’s exact tests) with factors associated with S. aureus nasal carriage. Twenty one (10%) S. aureus strains were isolated from 209 nasal swab samples. 14 isolates were from pre-clinical students while the remaining seven were from clinical students. There was no significant association between gender, ethnicity, health status, skin infection and students’ exposure to hospital environment with S. aureus nasal carriage (p>0.05). Nineteen (90.5%) isolates were resistant to penicillin and there was also no significant association between penicillin resistant and the students’ groups. One (5.3%) isolate was resistant to erythromycin. There was no methicillin-resistant S. aureus isolated in this study.