Abstract

Potential Virulence of Klebsiella Isolated from Enteral DietsVirulence of Klebsiella and Enteral Diets

Simone Cardoso Lisboa Pereira and Maria Cristina Danta Vanetti

Objective: To evaluate the potential virulence of Klebsiella isolates from enteral diets in hospitals, in order to support nosocomial infection control measures, especially among critical patients.

Methods: Capsular phenotypic expression of the external membrane, production of aerobactin siderophore, quantity of capsular polysaccharide, hemolytic and phospholipase activity and resistance to antibiotics that are used therapeutically were investigated in 15 strains of K. pneumoniae and six of K. oxytoca. These isolates were obtained from enteral diets in two public hospitals in the state of Minas Gerais, Brazil.

Results: The hypermucoviscous phenotype was observed in one of the K. pneumoniae isolates (6.7%). Capsular serotypes of types K1 to K6 were seen to be present, of which four were K5 isolates of K. pneumoniae and one was K4. Under the conditions of this study, no aerobactin production, hemolytic activity or lecithinase activity was observed. All the isolates presented resistance to the antibiotics amoxicillin and ampicillin, but they were sensitive to the antibiotics cefetamet, imipenem, cloranfenicol, gentamicin and sulfamethoxazole/trimethoprim. The K. pneumoniae isolates that originated from hospital B presented higher frequency of resistance to the antibiotics evaluated and multiple resistances to at least four antibiotics. The variations in the profile of resistance to antibiotics among the Klebsiella isolates made it possible to classify them into eight antibiotypes. No production of broad-spectrum β -lactamases was observed among the isolates.

Conclusion: The data obtained through this study favor the hypothesis that Klebsiella isolates from enteral diets are potential pathogens for nosocomial infections.