Spread of a methicillin-resistant staphylococcus aureus clone isolated from bacteremia in elderly patients in a Brazilian general hospital

A study of the genomic diversity of MRSA strains isolated from elderly patients with infection/colonization in three repeated prevalence, cross sectional studies was performed in the 1999-2000 period. In this study, 13 MRSA isolates from blood cultures and 5 from rectal and nare cultures were obtained from 18 patients (13 elderly and 5 adults). Most of the patients were being treated with two or more antimicrobials (83.3%), had insertion of invasive devices (88.9%) and were managed in ICU (Intensive Care Unit) and/or surgical units (66.7%). MIC (Minimum Inhibitory Concentration) data showed that 88.9% of the MRSA strains were resistant to high concentrations of oxacillin (MIC > 256 ìg/mL), 94.5% of the MRSA carried the mecA gene in their genome, and most (65.0%) of the isolates were indistinguishable according to their DNA finger­printing generated by PFGE (Pulsed-field gel electrophoresis). Although PFGE typing was performed with a few MRSA isolates, our results demonstrate that one MRSA clone was associated with infection/colonization in patients with an obvious connection among five out of eleven patients who stayed in the same clinic and ICU during the same period. Hospital acquired infection, a major “silent epidemy”, is associated with prolonged hospital stay and high mortality rate and its cause must be better evaluated.

Genotipificación de cepas de enterobacterias procedentes de 4 centros de salud del área de Caracas / Genotyping of enterobacterias strains from 4 healthcare centers in Caracas

Las infecciones nosocomiales pueden ser producidas por microorganismos resistentes a la acción de los antimicrobianos que han sido seleccionados por la mal uso ó el uso indiscriminado de los antibióticos en el ámbito hospitalario. En los últimos años se han desarrollado nuevas técnicas moleculares de tipificación basada en la reacción en cadena de la polimerasa (PCR), que han representado un avance importante en el estudio de las enfermedades infecciosas, siendo muy útiles al permitir diferenciar serotipos estrechamente relacionados y grupos de cepas no relacionadas clonalmente, debido a su gran poder discriminatorio. En Venezuela, son pocos los estudios de eepidemiología molecular de las infecciones intrahospitalarias, y por esta razón nos propusimos genotipificar cepas de Escherichia coli y Klebsiella pneumoniae provenientes de aislados nosocomiales de cuatro centros de salud del área metropolitana (Hospital "Dr. José María Vargas", Hospital "Dr. Domingo Luciani", Centro Médico de Caracas y Policlínica Metropolitana) con la finalidad de determinar la relación clonal existente entre estas cepas. El uso de ERIC-PCR permitió relacionar parcialmente las especies de E. coli aisladas en los cuatro centros de salud, sin embargo la técnica de REP-PCR permitió discriminar entre los patrones de bandas similares, mostrando un poder de resolución mayor. El uso de ERIC-PCR y REP-PCR no permitió tipificar la mayoría de las cepas de K. pneumoniae aisladas en los cuatro centros de salud en estudio. En el Centro Médico de Caracas se identificaron dos aislados clonales provenientes de diferentes áreas del hospital, Unidad de Terapia de Adultos y Hospitalización. En la Policlínica Metropolitana se identificaron tres aislados clonales, dos en la unidad de Terapia y uno en Hospitalización. En el Hospital "Dr. Domingo Luciani" y en el Hospital "Dr. José María Vargas" no se identificaron clones. Estos resultados proporcionan un aporte a los programas de vigilancia...

Nosocomial infections can be produced by microorganisms resistand to antimicrobial agents, and they have been selected by the bad use or abuse of antibiotics in the hospital environment. Recently, new molecular typing techniques have been developed, based on polymerase chain reaction (PCR). These techniques represent an important advantage the study of infectious diseases; they are able to discriminate relate closed serovars and groups of nonrelated isolates due to its great power discriminatory. In Venezuela, there is a small number of molecular epidemiology researches. The goal of the present study is genotyping Escherichia coli and Klebsiella pneumoniae isolated of nosocomial infected patients from four healthcare centers in the metropolitan area (Hospital "Dr. José María Vargas", Hospital "Dr. Domingo Luciani", Centro Médico de Caracas, Policlínica Metropolitana) in order to investigate the clonal relationship between the isolates. ERIC-PCR allowed us to correlate E. coli isolates however REP-PCR shows greater greater resolution. The use of both ERIC-PCR and REP-PCR, did not permit us typing K. pneumoniae isolates. Two clonally related isolates from Centro Médico de Caracas were identified. Three clonally related isolates from the Policlínica Metropolitana ere identified. No clones were identified in samples from Hospital "Dr. Domingo Luciani" and the Hospital "José María Vargas". These results contribute to monitoring programs, to improve the control of the bacterial infections, helping to establish efficient procedures and reduce nosocomials infections.

Characterization of the Brazilian endemic clone of methicillin-resistant staphylococcus aureus (MRSA) from hospitals throughout Brazil

The objective of this study was to characterize patterns of the Brazilian endemic clone of methicillin-resistant staphylococcus aureus (MRSA) from hospitals throughout Brazil. We studied 83 MRSA strains isolated from patients hospitalized in 27 public and private hospitals in 19 cities located in 14 brazilian states from september, 1995, to june, 1997. The MRSA strains were typed using antibiograms, bacteriophage typing and pulsed field gel electrophoresis (PFGE). The analysis of genomic DNA by PFGE showed that 65 isolates presented the same SFGE pattern. This pattern was presente in all of the hospitals studied indicating the presence of an endemic MRSA clone widely disseminated throughout brazilian hospitals (BEC). All isolates belonging to the BEC proved to be resistant to ciprofloxacin, erythromycin, lincomycin, trimethoprim-sulphamethoxazole, and tetracycline. Variable susceptibility to these drugs was found only in isolates belonging to clones other than the BEC. The results show that, among MRSA, the BEC is common in Brazil. The best method for mapping changes in the frequency of this clone among MRSA is pulsed field gel electrophoresis. Use of molecular mapping is an important tool for monitoring the spread of potentially dangerous microbes.

Biological parameters and molecular markers of clone CL brener - the reference organism of the Trypanosoma cruzi genome project

Clone CL Brener is the reference organism used in the Trypanosma cruzi Genome Project. Some biological paramenters of CL Brener were determined: (a) the doubling time of epimastigote forms cultured in liver infusion-tryptose (LIT) medium at 28ºC is 58ñ13 hr; (b) differentiation of epimastigotes to metacyclic trypomastigotes is obtained by incubation in LIT-20 per cent Grace's medium; (c) trypomastigotes infect mammalian cultured cells and perform the complete intracellular cycle at 33 and 37ºC; (c) blood forms are highly infective to mice; (e) blood forms are susceptible to nifurtimox and benznidazole. The molecular typing of CL Brener has been determined: (a) isoenzymatic profiles are characteristic of zymodeme ZB; (b) PCR amplification of a 24 alpha ribosomal RNA sequence indicates it belongs to T. cruzi lineage 1; (c) schizodeme, randomly amplified polymorphic DNA (RAPD) and DNA fingerprinting analyses were performed.

Effect of high temperature on Aedes albopictus cells infected with Mayaro virus

the multiplication of Mayaro virus in Aedes albopictus cells was drastically inhibited after incubation at 37-C. The effect of short-term exposure of infected cells to high temperatures (heat shock) produced a preferential translation of the heat shock messengers when compared to the viral mRNAs. When cells were shifted back to 28-C (the optimum growth temperature for Aedes albopictus cells), preferential translation of viral mRNA occurred. Although the infected cells were programmed for preferential translation of viral messengers, the therminal treatment was able to shif the translational machinery towards synthesis of heat shock proteins