The cassette chromosome mec (SCCmec) present in methicillin-resistant Staphylococcus aureus (MRSA) has two essential components, the ccr gene complex and the mec gene complex. Additionally, SCCmec has non-essential components called J regions which are used for MRSA subtyping. This study was performed to determine subtypes MRSA strains carrying SCCmec type I based on polymorphism of regions located downstream of the mecA gene. A total of 98 MRSA strains carrying SCCmec type I isolated from patients hospitalized at the County Hospital of Valdivia (Chile) between May 2007 and May 2008, were analyzed by multiplex PCR designed to amplify the mecA gene and 7 DNA hypervariable regions located around the mecA gene. MRSA strains were classified into seventeen genotypes accordingly to amplification patterns of DNA hypervariable regions. Five genotypes showed amplification patterns previously described. The remaining twelve genotypes showed new amplification patterns. Genotypes 18 and Genotype 19 were the most frequently detected. Regions HVR, Ins117 and pI258 stand out as being present in more than 60% of tested isolates. The acquisition of hypervariable regions by MRSA is a continuous horizontal transfer process through which the SCCmec have been preserved intact, or even may give rise to new types and subtypes of SCCmec. Therefore it is possible to infer that most MRSA strains isolated at the County Hospital of Valdivia (Chile) were originated from two local clones which correspond to Genotype 18 and Genotype 19.

In the present study, we determined the frequency of superficial and cutaneous mycoses and their etiologic agents during a 7-year period (2002-2008) in Natal, Brazil. A total of 1,717 specimens of skin, nail, and hair were collected from 1,382 patients with suspected mycoses lesions and were then subjected to direct microscopy and culture.

Background: Methicillin resistant strains of Staphylococcus aureus (MRSA) are an important cause of nosocomial infections. Aim: To determine the genotypes of MRSA strains. Material and methods: Fifty five strains of MRSA, isolated from patients hospitalized in Hospital Base Valdivia, were studied. The phenotype was determined through MicroScan® in all strains and by minimum inhibitory concentration (MIC) in 41. The genotype of the strains was analyzed by a duplex polymerase chain reaction (PCR) of the mecA gene, amplifying eight hypervariable DNA regions associated to such gene. Results: According to MIC, 88% of strains had a pattern of resistance against multiple antimicrobial (penicillin, ampicillin, cephradine, gentamycin, ciprofloxacin, ¡incomycin and erythromycin). Vancomicin resistan strains were not detected. Only 53 strains (96%) had at least one of the eight hypervariable regions and were classified as MRSA. Genotypic patterns types 15 were the most commonly detected in 38% and 34% of strains, respectively. MicroScan® erroneously classified five strains in an incorrect phenotype, according to results obtained with duplex PCR. MIC results did not differ from those of duplex PCR. Conclusions: Duplex- PCR is a useful tool to detect hyper variable regions associated to mecA gene

Ventilator associated pneumonia (NAVM) is one of the most frequent nosocomial infections (NI) and of more impact in morbidity and mortality in Chile. In spite of the habitual measures of prevention of NI applied in our hospital during the year 2002, an increase was observed in the rate of NAVM, next to the isolation of a larger percentage of Acinetobacter baumannii, an endemic strain. In order to identify possible niches of NI microorganisms, a study was planned which involved the patient (tracheal secretion) and the ventilation systems; humidifier, endotracheal tube, Y tube, and ventilator-tubing. The ventilator tubing was studied by sweeping microscopy to specify characteristics of the material. After seven days, time of replacement settled down by the National Committee of NI, colonization was observed for A. baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae, agents associated to NI in two patients. In pre-sterilization like in post-sterilization the circuit of mechanic ventilation belonging to a patient with nosocomial pneumonia was studied and in both cultures, multi-resistant microorganisms were isolated. When analyzing by sweeping microscopy portions of the circuit, a wearing of the tubing was observed with multiple cracks with coccoidal and bacilar forms included in the structure. When studying different circuits, both pre and post-sterilization, in two of them positive cultures were obtained after the sterilization in ethylene oxide. Our data emphasizes the necessity of incorporating routinely in the guidelines of infection control, those related to reusable material.

La neumonía asociada a ventilación mecánica (NAVM) en Chile, es una de las infecciones intrahospitalarias (IIH) más frecuentes y de mayor impacto en morbimortalidad. A pesar de las medidas habituales de prevención de IIH aplicadas en nuestro hospital, se presentó en el año 2002 un aumento en la tasa de NAVM, junto al aislamiento de un mayor porcentaje de Acinetobacter baumannii, cepa endémica en nuestro hospital. Con el fin de identificar posibles nichos de microorganismos nosocomiales, se realizó un plan de estudio, que involucró al paciente (secreción traqueal) y los sistemas de ventilación, humidificadores, tubo endotraqueal, tubo en Y, mangueras del sistema de ventilación. Se estudió por microscopia de barrido las mangueras de ventilación para precisar características del material. Se observó, al cabo de 7 días, tiempo de recambio establecido por el Comité Nacional de IIH, colonización por A. baumannii, Pseudomonas aeruginosa y Klebsiella pneumoniae, agentes asociados a NAVH en 2 pacientes. Se estudió el circuito de ventilación mecánica perteneciente a un paciente con NAVM tanto preesterilización como postesterilización, aislándose en ambos cultivos microorganismos multiresistentes. Al analizar porciones del circuito por microscopia de barrido se observó un desgaste de las mangueras con múltiples grietas con formas cocoides y bacilares incluidas en la trama. Al estudiar diferentes circuitos pre y posesterilización, se observó en 2 circuitos cultivos positivos con posterioridad a la esterilización en oxido de etileno. Nuestros datos dan énfasis a la necesidad de incorporar en forma rutinaria dentro de las normas de control de IIH las relacionadas a material reutilizable.