Diversity in Acinetobacter baumannii isolates from paediatric cancer patients in Egypt

Acinetobacter baumannii is an important nosocomial pathogen, commonly causing infections in immunocompromised patients. It is increasingly reported as a multidrug-resistant organism, which is alarming because of its capability to resist all available classes of antibiotics including carbapenems. The aim of this study was to examine the genetic and epidemiological diversity of A.baumannii isolates from paediatric cancer patients in Egypt, by sequencing the intrinsic bla(OXA-51-like) gene, genotyping by pulsed-field gel electrophoresis and multi-locus sequence typing in addition to identifying the carbapenem-resistance mechanism. Results showed a large diversity within the isolates, with eight different bla(OXA-51-like) genes, seven novel sequence types and only 28% similarity by pulsed-field gel electrophoresis. All three acquired class-D carbapenemases (OXA-23, OXA-40 and OXA-58) were also identified among these strains correlating with resistance to carbapenems. In addition, we report the first identification of ISAba2 upstream of bla(OXA-51-like) contributing to high-level carbapenem resistance. This indicates the presence of several clones of A.baumannii in the hospitals and illustrates the large genetic and epidemiological diversity found in Egyptian strains.