Colonización por bacterias multirresistentes en unidades de alto riesgo de una institución polivalente / Colonization by multidrug-resistant bacteria in high-risk units of a multipurpose institution

Las infecciones asociadas al cuidado de la salud representan una causa de elevada morbilidad y mortalidad en todos los sistemas sanitarios. Aquellas causadas por microorganismos multirresistentes (MMR) son una realidad generadora de brotes intrahospitalarios difíciles de erradicar. Entre las formas de manejo internacionalmente aceptadas destacan el uso racional de antimicrobianos y el aislamiento de los casos detectados. Los objetivos del presente trabajo fueron evaluar, mediante cultivo nasal y rectal, el estado de colonización por MMR en pacientes con largas estadías hospitalarias, determinar las especies bacterianas predominantes, los perfiles de resistencia prevalentes e identificar aquellos pacientes que adquirieron una infección por MMR. Fue un estudio observacional, descriptivo, prospectivo. Se estudiaron pacientes mayores de 20 años de edad, internados por más de diez días en la institución y aquellos que, proviniendo de otros centros de salud, centros de rehabilitación o geriátricos requirieron internación en la clínica. En el período de agosto de 2013 a agosto 2014 se realizaron cultivos de vigilancia mediante hisopado nasal para búsqueda de Staphylococcus aureus resistente a la meticilina (SARM) e hisopado rectal para Enterococos resistentes a vancomicina (EVR) y enterobacterias productoras de betalactamasas de espectro extendido (EB-BLEE). Se comprobó colonización por alguno de los MMR en el 31% de los pacientes. La distribución por MMR fue la siguiente: SARM, 5%; EVR, 10%, y EB-BLEE, 25%, con predominio de Escherichia coli y Klebsiella pneumoniae. De los pacientes colonizados, el 16% presentó infección. Escherichia coli, Klebsiella pneumoniae y Klebsiella oxytoca fueron los agentes más frecuentes, recuperados principalmente de infecciones urinarias y bacteriemias. En cuanto al comportamiento frente a otros antibióticos, los aislamientos de SARM fueron sensibles a trimetoprima-sulfametoxazol. Todos los EVR pertenecían a la especie E. faecium y presentaron un alto nivel de resistencia a aminoglucósidos sumada a la resistencia a ampicilina, lo cual limita el tratamiento sinérgico en infecciones graves. En las EB-BLEE las resistencias frecuentemente asociadas fueron a trimetoprima-sulfametoxazol. Todos los EVR pertenecían a la especie E. faecium y presentaron un alto nivel de y fluorquinolonas, manteniendo sensibilidad frente a carbapenémicos. Es importante conocer los perfiles de resistencia a otros antimicrobianos que pueden constituir una opción terapéutica. Es notoria y conocida la variación geográfica de los resultados de colonización, por lo que cada institución debería efectuar cultivos de vigilancia para conocer su situación y mejorar el control

Healthcare associated infections (HAI) cause high morbidity and mortality in all healthcare systems. Those caused by multidrug-resistant microorganisms (MDRO) can trigger clinical infections that are difficult to treat. Among the internationally recognized forms of treatment are the rational use of antimicrobials and isolation of detected cases. The objectives were to assess the prevalence of colonization by MDROs in patients with long hospital stays by nasal and rectal cultures, to determine the predominant bacterial species, the prevalent resistance profiles and to identify those patients who acquired MDRO infections. An observational and descriptive study was conducted. Adults over the age of 20 with more than ten days stay in the hospital or patients from other healthcare facilities, rehabilitation centers or long-term care facilities (nursing homes) were studied. In the period August 2013-2014, surveillance cultures were performed using nasal swabs to search for methicillin resistant Staphylococcus aureus (MRSA) and rectal swabs for vancomycin-resistant enterococci (VRE) and extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-EB). Colonization was evidenced by some of the MMR in 31% of patients. MDRO distribution was as follows: 5% MRSA, 10% VRE and 25% ESBL-EB, predominantly Escherichia coli and Klebsiella pneumoniae. Among colonized patients 16% developed an infection. Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca were the most common agents recovered mainly from urinary tract and bloodstream infections. When other antibiotics were used, the MRSA isolations were sensitive to trimethoprim/sulfamethoxazole (TMP-SMZ). All VRE belonged to the species E. faecium and presented a high level of resistance to aminoglycosides; this condition, as well as resistance to ampicillin, restricts synergic treatment in serious infections. In the ESBL-EB the most frequently reported resistance was to TMP-SMZ and to fluorquinolones, while retaining sensitivity to carbapenems. It is important to know the resistance profiles to other antimicrobials as possible therapeutic options. Because of the wide geographic variation in the results of colonization, each institution should carry out surveillance cultures to discover their status and improve control thereof

Risk factors of oropharyngeal carriage of Pseudomonas aeruginosa among patients from a Medical-Surgical Intensive Care Unit

Oropharyngeal carriage of Pseudomonas aeruginosa is associated with increased risk of infection and may provide a source for spread of drug-resistant strains. In order to assess the incidence and risk factors of oropharyngeal carriage, we conducted a retrospective cohort study based on results of surveillance cultures (oropharyngeal swabs) from a medical-surgical intensive care unit, collected from March 2005 through May 2006. Variables investigated included demographic characteristics, comorbid conditions, invasive procedures, use of devices and use of antimicrobials. Thirty case patients with P. aeruginosa carriage were identified. Other 84 patients with surveillance cultures negative to P. aeruginosa were enrolled as control subjects. Case patients were more likely to have a solid malignancy (Odds Ratio [OR] = 12.04, 95 percent Confidence Interval [CI] = 1.93-75.09, p=0.008), Acquired Immunodeficiency Syndrome (AIDS, OR = 7.09, 95 percent CI= 1.11-45.39, p = 0.04), central nervous system disease (OR = 4.51, 95 percent CI = 1.52-13.39, p = 0.007), or to have a central venous catheter placed (OR = 7.76, 95 percent CI = 1.68-35.79, p=0.009). The use of quinolones was a protective factor (OR = 0.13, 95 percent CI = 0.03-0.47, p = 0.002). The predominance of comorbidities as risk factors points out a group of patients to whom preventive measures should be directed.