RESUMO
Colistin heteroresistance in Acinetobacter baumannii (Ab) has been reported, but the clinical impact and the antimicrobial treatment have not been established yet. We observed the selection intratreatment with colistin of Ab colistin-resistant strains from a colistin-heteroresistant isolate in one patient with postneurosurgical meningitis. The presence and the genetic relationship of heteroresistant Ab isolates from intensive care units (ICUs) obtained in the same period of the case report were analyzed. Twenty-eight isolates from patients admitted to the ICUs of an Argentinian university hospital during June to December 2004 were evaluated. Genomoespecie was determined by amplified ribosomal DNA restriction analysis, and genetic similarity among the strains was determined by pulsed-field electrophoresis. Colistin heteroresistance was observed in 46, 4% of these isolates. The majority belonged to clones previously identified as I and III.
Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/uso terapêutico , Colistina/uso terapêutico , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana , Meningites Bacterianas/microbiologia , Seleção Genética , Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Argentina , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Colistina/farmacologia , Infecção Hospitalar/tratamento farmacológico , Impressões Digitais de DNA , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Hospitais Universitários , Humanos , Unidades de Terapia Intensiva , Masculino , Meningites Bacterianas/tratamento farmacológico , Ribotipagem , Adulto JovemRESUMO
Non-enterococcal Gram-positive bacteria that are intrinsically vancomycin-resistant have been infrequently isolated in association with serious infections. However, well-documented infections have lately been reported with increasing frequency. Because these organisms may be pathogens, we tested the MICs of 19 antimicrobial agents by the agar dilution method for predicting susceptibility. The activity of these antimicrobial agents was assessed against 28 strains (Lactobacillus rhamnosus, 6; Lactobacillus acidophilus, 1; Lactobacillus casei, 1; Lactobacillus fermentum, 2; Lactobacillus brevis, 1; Lactobacillus plantarum, 1; Weissella confusa, 2; Leuconostoc mesenteroides, 7; Leuconostoc lactis, 4; Pediococcus acidilactici, 2; Pediococcus pentosaceus, 1), isolated from clinical specimens in an Argentinian university hospital from 1997 to 2003. The MICs of penicillin for 67% of the Lactobacillus strains and 100% of the Leuconostoc spp. and Pediococcus spp. strains tested were in the 0.25-2 microg/mL range. Erythromycin was the most active antimicrobial overall. Multiresistance was observed in 2 strains (Lactobacillus rhamnosus, 1; Lactobacillus plantarum, 1).