Cepas de Pseudomonas aeruginosa de origen hospitalario multirresistentes a 21 antibióticos

The resistance profile to 21 antibiotics in 24 strains of Pseudomonas aeruginosa strains from the Infectology Hospital of the Mexican Institute of Social Security (IMSS) in Mexico was performed. The samples were collected during a period of three months corresponding to two isolations per week. P. aeruginosa identification was achieved by microbiological standard procedures. The susceptibility to 21 antibiotics was investigated by using the disk diffusion method, and the agar dilution method for imipenem according to the recommendations of the Clinical Laboratory and Standards Institute of the United States of America (CLSI). Fourteen of the 24 strains showed a multiresistant phenotype to 21 antibiotics tested; while 6 strains showed resistance only to 2 antibiotics. These results indicate that during a three month period in the hospital under study there was a coexistence of multiresistant and low marker resistance strains sharing the ecological niche. The most effective antibiotic against P. aeruginosa was imipenem. The minimal inhibitory concentration for imipenem was up to 64 µg/mL for most of the multiresistant strains. This study demonstrated the presence of 14/24 multiresistant P. aeruginosa strains over a 3 month period. Our findings emphasize the need to reinforce the measures of infection control related to the use and abuse of antibiotics that favor the selection of P. aeruginosa strains resistant to antibiotics recommended for treatment.