Aspectos epidemiológicos e microbiológicos relacionados à colonização de pacientes por micro-organismos multirresistentes em unidade de terapia intensiva

Abstract

The bacterial resistance is a global public health concern. The colonization and/or infection with resistant bacteria are highligthed in Intensive Care Unit (ICU). These microorganisms generally are carried by patient for different times. It was aimed to determine the epidemiological and microbiological characteristics of patient colonization with multidrug-resistant bacteria in Intensive Care Unit (ICU) and after hospital discharge. It was a prospective cohort of patients colonized and/or infected with multidrug-resistant bacteria at two adult ICUs from hospitals in Brazil and after discharge with evaluation of familiar contacts (April 2012- February 2013). Data were collected from chart review. Nasal cavity, groin and perineum swab were performed and cultured in selective media for 48 h at 37ºC. Tests were performed for identification (Vitek - BioMérieux), antibiogram - Bauer-Kirby method ( Vancomycin, imipenem, cefoxitin, ciprofloxacin and third generation cefalosporins) or Minimum Inhibitory Concentration was used for Staphylococcus aureus. For samples characterization were performed Polymerase Chain Reaction (PCR), sequencing and rep-PCR (Diversilab). Statistical analysis was performed. There were 53 cases of colonization, and 26 of these resulted in infection. The cocolonization with Gram-negative and Gram-positive microorganisms were verified with patients (74%). In colonization were identified imipenem-resistant Acinetobacter baumannii (51%), Pseudomonas aeruginosa (32%), Klebsiella pneumoniae ESBL (38%) or imipenem resistant (5.6%), vancomycin-resistant Enterococcus faecalis (43%), and oxacillin-resistant Staphylococcus aureus (7.5%). In infection Acinetobacter baumannii (34,6%) and Pseudomonas aeruginosa (11,5%) resistant to carbapenems, Klebsiella pneumoniae ESBL (27,0%) or carbapenemases producing (7,7%) and VRE (19,0%). For ORSA were not registered infections. The antimicrobial (p = 0,01) and medical devices (p = 0,03) were important in infection occurrence by carbapenem resistant Acinetobacter baumannii with similar phenotype of those registered in colonization. The mean time of microbial load decreasing ranged from 27 to 41 days (7,0 to 1,0 log10 CFU/ml). Among colonized patients 45,0% (24/53) showed microbial load reduction and 8 died until hospital discharge. However, 39,0% (21/53) of patients were colonized until hospital discharge. In the community 20 patients were followed with persistance of one colonization case by Klebsiella pneumoniae producing carbapenemases and one colonization case by VRE with hospital readmission. The use of polimixin E in ICU related to microbial load decreasing of Gram-negative bacteria (p = 0,0001). For four familiar contacts were verified only normal microbiota. Among colonized patients was verified important microbial load decreasing in low level with possibility of reducing microorganisms spread.