Susceptibilidad antimicrobiana de cepas de Pseudomonas aeruginosa aisladas en el laboratorio del Hospital Regional Dr. Leonardo Guzmán de Antofagasta, Chile / In vitro antimicrobial susceptibility of Pseudomonas aeruginosa strains isolated at Hospital Dr. Leonardo Guzmán, Antofagasta, Chile

Pseudomonas aeruginosa es un patógeno nosocomial frecuente que presenta elevada resistencia a los antimicrobianos y causa infecciones graves cuando hay alteración de los mecanismos defensivos del paciente. Así, conocer los patrones locales de sensibilidad es importante para la elección del tratamiento antimicrobiano adecuado en cada institución. En este trabajo determinamos la susceptibilidad antimicrobiana de cepas de P. aeruginosa aisladas desde pacientes atendidos en el Hospital Regional de Antofagasta. La mayoría de los pacientes tenía alguna condición predisponente a la infección y 48% tenía una infección grave. Las cepas mostraron mayor resistencia a los antimicrobianos que lo reportado en trabajos nacionales previos. Las cepas fueron altamente resistentes a amikacina (36,8%), ceftazidima (36,8%) y ciprofloxacina (68,4%), moderadamente resistentes a imipenem (26,3%), mientras que eran escasamente resistentes a piperacilina/tazobactam (5,3%) y cefoperazona/sulbactam (15,8%), Este es el primer trabajo, realizado en nuestra región, que estudia la susceptibilidad de P. aeruginosa frente a distintos grupos de antimicrobianos utilizados en clínica.

Pseudomonas aeruginosa is a nosocomial pathogen that often displays a high degree of antibiotic resistance. This pathogen causes also serious infections specially in patients with severe diseases or immunodeficiency. To offer the best treatment in every institution it is necessary to know the local pattern of antimicrobial susceptibility, then we studied the antibiotic susceptibility of P. aeruginosa strains isolated from patients attended in the Regional Hospital of Antofagasta. Most of them had an underlying disease that predisposed them to the infection and 48% had a severe infection. The strains showed higher drug resistance than that reported by other chilean researchers. P. aeruginosa displayed high resistance to amikacin (36,8%), ceftazidime (36,8%) and ciprofloxacin (68,4%) intermediate resistance to imipenem (26,3%), but low resistance to piperacillin/tazobactam (5,3%) and cefoperazone/sulbactam (15,8%). This is the first drug susceptibility study conducted in the Second Region of Chile, where P. aeruginosa was assayed against those antibiotics used in the clinical practice.

Relaciones fenotípicas y moleculares entre cepas de vibrio cholerae 01 aisladas en Chile, Perú y Bolivia: comparación con cepas de reservorios ambientales / Phenotypical and molecular relation between vibrio cholerae 01 strains, isolated in Chile, Perú and Bolivia: comparison with strains from environmental reservoirs

The phenotype, biotype and susceptibility to nine antimicrobials was determined for each isolated strain. Also, the genes of cholera and termolabile toxins were determined using DNA probes and a chromosomal restriction profile was done using HindIII, EcoRI and NotI enzymes. Features studied were similar in the 53 strains isolated from patients. Those isolated from environmental reservoirs had different antimicrobial susceptibility, showing ampicillin resistance and the GT gene was detected in one of 20 strains, compared to clinical samples were it was present in all. Strains isolated from patients and envirinment had similar chromosomal restriction profiles. The chromosomal restriction profile gives an image of bacterial genome and it is a useful and reliable tool for the epidemiological surveillance of cholera