Caracterización de infecciones por bacterias productoras de BLEE en un hospital de referencia nacional / Characterization of ESBL-producing bacteria infections on a national referral hospital

La resistencia mediante la producción de betalactamasa de espectro extendido (BLEE) es la resistencia microbiana más común y de importancia en salud pública. Objetivos: Describir las características de las infecciones por bacterias productoras de BLEE en un hospital de referencia nacional. Diseño: Estudio transversal descriptivo. Lugar: Hospital Nacional Daniel Alcides Carrión, Callao, Perú. Materiales: Registros de los cultivos de secreciones realizados en el Laboratorio de Microbiología del HNDAC en el año 2012. Métodos: Se analizó datos del paciente (edad, sexo y servicio del cual se recibió la muestra) y datos de la muestra (fecha de obtención, el tipo de muestra, el microrganismo encontrado, el antibiograma detallado y su calificación como bacteria productora de BLEE). Principales medidas de resultados: Características de las infecciones por bacterias productoras de BLEE. Resultados: Se recolectó 3 149 muestras, 70,9 por ciento (2 235) fueron de mujeres; 29,4 por ciento fueron cultivos positivos para bacterias productoras de BLEE. Los servicios críticos obtuvieron la mayor prevalencia, y los meses donde se encontró mayor presencia fueron abril (34,7 por ciento) y julio (34,7 por ciento). Tanto E. coli (72,4 por ciento) como Klebsiella sp. (20 por ciento) fueron las prevalentes. No se encontró resistencia para imipinem, tanto para E. coli como para Klebsiella sp. Conclusiones: La prevalencia fue similar a la de América Latina (34,6 por ciento). Se presenta más evidencias de una alta presencia en consulta externa y en mayores de 46 años; siendo así un problema de salud pública...

Resistance by extended-spectrum beta-lactamase (ESBL) is the most common antimicrobial resistance and of public health importance. Objectives: To describe ESBL producing bacteria characteristics in a national reference hospital. Design: Cross sectional, descriptive study. Setting: Hospital Nacional Daniel Alcides Carrión, Callao, Peru. Materials: Records of secretion cultures done in the hospital Laboratory of Microbiology during 2012. Methods: Patient data (age, sex and service from which the sample was received) and sample data (date of collection, sample type, microorganism found, sensitivity and detailed classification as ESBLproducing bacteria) were analyzed. Main outcome measures: Characteristics of infections by ESBL-producing bacterias. Results: Study included 3 149 samples, 70.9 per cent (2 235) from female patients; 29.4 per cent were cultures positive for ESBL-producing bacteria. Critical services had the highest prevalence, and months with highest occurrence were April (34.7 per cent) and July (34.7 per cent). Both, E. coli (72.4 per cent) and Klebsiella sp. (20.0 per cent) were the most prevalent. No imipinem resistance was found for E. coli or Klebsiella sp. Conclusions: The prevalence was similar to that of Latin America (34.6 per cent). More evidence of high prevalence in outpatients and patients over 46 year-old is presented, considering it a public health problem...

Antimicrobial susceptibility of Brucella melitensis isolates in Peru.

Brucellosis is an important public health problem in Peru. We evaluated 48 human Brucella melitensis biotype 1 strains from Peru between 2000 and 2006. MICs of isolates to doxycycline, azithromycin, gentamicin, rifampin, ciprofloxacin, and trimethoprim-sulfamethoxazole were determined by the Etest method. All isolates were sensitive to tested drugs during the periods of testing. Relapses did not appear to be related to drug resistance.

Molecular epidemiology of Brucella genotypes in patients at a major hospital in central Peru.

The multiple-locus variable-number repeat analysis of 90 human Brucella melitensis isolates from a large urban area in central Peru revealed variations at 4 (Bruce07, Bruce09, Bruce18, and Bruce42) out of 16 loci investigated, of which 1 (Bruce42) also is used for species identification. Ten genotypes were identified, separated by the number of Bruce42 repeats into two groups that may have distinct phenotypic characteristics. Whereas genotypes with five or six Bruce42 repeats were cultured mainly from adult patients, genotypes with three Bruce42 repeats were isolated from children and young adolescents as well as from adults. In addition, the isolates with three Bruce42 repeats were obtained more often from patients with splenomegaly (P = 0.02) or hepatomegaly (P = 0.006). An annual variation in the diversity of genotypes was observed, possibly reflecting changes in sources of fresh dairy products, supply routes to city shops and markets, and the movement of infected dairy goat herds.

Comparison of culture techniques at different stages of brucellosis.

The lysis centrifugation technique is preferred for culturing Brucella spp. at all stages of brucellosis because it yields 25% more positive results and on average provides results 10 days earlier than the Ruiz-Castaneda method. This lysis method is inexpensive and easier to use and may be used in laboratories with limited expertise or equipment if all safety precautions are taken.

Brucellosis in household members of Brucella patients residing in a large urban setting in Peru.

During home visits and using a point-of-care test for brucellosis, we screened the household members of adult patients found to have brucellosis by investigation at the Hospital Nacional Daniel Alcides Carrión in Callao, Peru. A total of 206 household members of 43 patients were screened, and 15 (7.3%) household members in 10 (23.3%) households tested seropositive. Brucellosis was diagnosed in 14 of them, all but 4 presenting with acute or subacute uncomplicated disease. Regardless of attempts to control brucellosis in Peru, the disease continues to be reasonably common among household members of brucellosis patients. Household members presumably remain the single most important identifiable risk group in an urban setting, and screening them provides an effective means for their early diagnosis. Although contact with livestock was rare, the consumption of unpasteurized dairy products was reported by almost all patients with brucellosis, their household members, and hospitalized non-brucellosis patients.

Evaluation of brucellosis by PCR and persistence after treatment in patients returning to the hospital for follow-up.

Polymerase chain reaction (PCR) was applied to confirm the diagnosis of brucellosis and to study its clearance in response to the standard treatment regimen with doxycycline and rifampin at hospitals in Callao and Lima, Peru. The PCR confirmed the diagnosis in 23 (91.7%) patients with brucellosis including 12 culture-confirmed cases. For patients treated at the hospital in Callao, PCR was positive for all samples collected during and at the conclusion of treatment and for 76.9% of follow-up samples collected on average 15.9 weeks after completion of treatment. For patients treated at the hospital in Lima, PCR tests were positive for 81.8% of samples collected during treatment, for 33.3% of samples collected at the conclusion of treatment, and for > or = 50% of samples collected at first, second, and third post-treatment follow-up. Thus, Brucella DNA may persist in the serum weeks to months after completion of the standard treatment regimen.

Natural ventilation for the prevention of airborne contagion.

BACKGROUND: Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. METHODS AND FINDINGS: The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p < 0.001). Facilities built more than 50 years ago, characterised by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p < 0.001). Even within the lowest quartile of wind speeds, natural ventilation exceeded mechanical (p < 0.001). The Wells-Riley airborne infection model predicted that in mechanically ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. CONCLUSIONS: Opening windows and doors maximises natural ventilation so that the risk of airborne contagion is much lower than with costly, maintenance-requiring mechanical ventilation systems. Old-fashioned clinical areas with high ceilings and large windows provide greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion.