Extent of antimicrobial resistance in Acinetobacter species in a Tertiary Care Teaching Hospital

Abstract

Acinetobacter, gram negative coccobacillus, has become a frequent pathogen in hospitals and other health care settings. Acinetobacter species cause a wide variety of illness in debilitated and hospitalized patients especially in intensive care units (ICU). Carbapenems constitute the backbone of treatment of complicated Acinetobacter infections. However, resistance to Carbapenem is established and observed globally, leading to limited therapeutic options. The study was designed to understand the extent of resistance in Acinetobacter species in our hospital which is located in an island separated from mainland India.Isolates showing resistance to either Imipenem (IMP) and/or Meropenem by disc diffusion method was considered as Carbapenamase producing and further subjected to identification by phenotypic methods. Of the 160 isolates, 111 were resistant to either Imipenem and/or Meropenem. The susceptibility patterns of antibiotics tested suggests high resistance to 3rd/4th generation Cephalosporins (CTR 93.7%, CAZ 88.29%, CPM 85.59%) and least resistance to Colistin and Polymyxin B. MHT alone was positive in 66.98% isolates suggesting production of OXA type class D β-lactamase and DDST alone was positive in 7.55% isolates suggesting production of Metallo-β-lactamase /Group B β-lactamase. The present study adds to the literature available in respect to increasing instances of Carbapenem resistance and their presumptively mechanism of resistance.