Emergence and spread of carbapenem-resistant Acinetobacter baumannii international clones II and III in Lima, Peru

Emerg Microbes Infect. 2018 Jul 4;7(1):119. doi: 10.1038/s41426-018-0127-9.

Abstract

Carbapenem-resistant Acinetobacter baumannii is the top-ranked pathogen in the World Health Organization priority list of antibiotic-resistant bacteria. It emerged as a global pathogen due to the successful expansion of a few epidemic lineages, or international clones (ICs), producing acquired class D carbapenemases (OXA-type). During the past decade, however, reports regarding IC-I isolates in Latin America are scarce and are non-existent for IC-II and IC-III isolates. This study evaluates the molecular mechanisms of carbapenem resistance and the epidemiology of 80 non-duplicate clinical samples of A. baumannii collected from February 2014 through April 2016 at two tertiary care hospitals in Lima. Almost all isolates were carbapenem-resistant (97.5%), and susceptibility only remained high for colistin (95%). Pulsed-field gel electrophoresis showed two main clusters spread between both hospitals: cluster D containing 51 isolates (63.8%) associated with sequence type 2 (ST2) and carrying OXA-72, and cluster F containing 13 isolates (16.3%) associated with ST79 and also carrying OXA-72. ST2 and ST79 were endemic in at least one of the hospitals. ST1 and ST3 OXA-23-producing isolates were also identified. They accounted for sporadic hospital isolates. Interestingly, two isolates carried the novel OXA-253 variant of OXA-143 together with an upstream novel insertion sequence (ISAba47). While the predominant A. baumannii lineages in Latin America are linked to ST79, ST25, ST15, and ST1 producing OXA-23 enzymes, we report the emergence of highly resistant ST2 (IC-II) isolates in Peru producing OXA-72 and the first identification of ST3 isolates (IC-III) in Latin America, both considered a serious threat to public health worldwide.

MeSH terms

  • Acinetobacter Infections / epidemiology*
  • Acinetobacter Infections / microbiology*
  • Acinetobacter Infections / transmission
  • Acinetobacter baumannii / classification*
  • Acinetobacter baumannii / drug effects*
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / isolation & purification
  • Carbapenems / pharmacology*
  • Communicable Diseases, Emerging / epidemiology
  • Communicable Diseases, Emerging / microbiology
  • Electrophoresis, Gel, Pulsed-Field
  • Genes, Bacterial
  • Humans
  • Microbial Sensitivity Tests
  • Multilocus Sequence Typing
  • Peru / epidemiology
  • beta-Lactam Resistance*

Substances

  • Carbapenems