Indications of carbapenem resistance evolution through heteroresistance as an intermediate stage in Acinetobacter baumannii after carbapenem administration.
We describe an in vivo evolution of an antimicrobial profile from susceptibility to full-resistance to carbapenems, with heteroresistance as an intermediate stage, in an Acinetobacter baumannii strain. Heteroresistance was characterized by the growth of sub-populations within the susceptibility halo in both disk-diffusion and Etest. PCRs for the main A. baumannii carbapenemases were negative. The exact resistance mechanism, diagnostic methods and clinical relevance of heteroresistance in A. baumannii warrant further investigations. This is the first description of such phenomenon in vivo and the second report of heteroresistance to carbapenems in A. baumannii.
Superti
Silvana Vargas
SV
Laboratory of Microbiology, Hospital São Lucas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil. silvanas@ufcspa.edu.br
Martins
Daniela de Souza
Dde S
Caierão
Juliana
J
Soares
Fabiana da Silva
Fda S
Prochnow
Taísa
T
Zavascki
Alexandre Prehn
AP
D000151:Acinetobacter Infections / Q000188:drug therapy / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000187:drug effects*; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D052978:Disk Diffusion Antimicrobial Tests; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D015378:Imipenem / Q000494:pharmacology* / Q000627:therapeutic use; D000077731:Meropenem; D010641:Phenotype; D013845:Thienamycins / Q000494:pharmacology* / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D013845:Thienamycins; D015378:Imipenem; D000077731:Meropenem