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 blaOXA -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 blaOXA -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 blaOXA -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.

No abstract

Carbapenem resistant Acinetobacter baumannii (CRAb) is an important global pathogen contributing to increased morbidity and mortality in hospitalized patients, due to limited alternative treatment options. Nine international clonal (IC) lineages have been identified in many countries worldwide, however, data still lacks from some parts of the world, particularly in Africa. We hereby present the molecular epidemiology of MDR A. baumannii from four hospitals in Khartoum, Sudan, collected from 2017 to 2018. Forty-two isolates were whole-genome sequenced, and subsequent molecular epidemiology was determined by core genome MLST (cgMLST), and their resistomes identified. All isolates had an array of diverse antibiotic resistance mechanisms conferring resistance to multiple classes of antibiotics. We found a predominance (88%) of IC2 (with the intrinsic OXA-66 and acquired OXA-23), and some with NDM-1. IC2 isolates were sub-divided into 4 STs separated by 5 to 431 allelic differences, and with evidence of seven transmission clusters. Isolates belonging to IC1, IC5, and IC9 were also identified. These data illustrate that MDR IC2 A. baumannii are widely distributed in Khartoum hospitals and are in possession of multiple antibiotic resistance determinants.

Background Acinetobacter baumannii is an increasingly worrying organism in the healthcare setting, due to its multidrug resistance and persistence. Prolonged hospitalisation, immunocompromised patients and excessive antibiotic exposure all contribute to increasing the risk of A. baumannii infections, which makes cancer patients a significant risk group. This study aims to investigate the dissemination of A. baumannii at the National Cancer Institute (NCI) in Cairo – Egypt. Methods All bacterial isolates were typed using Multi-locus Sequence Typing (MLST) to characterise the epidemiology of isolates. The intrinsic OXA-51-like, and the acquired carbapanemases OXA-23, − 24/40, − 58, NDM, IMP, and VIM were also amplified and sequenced to genetically identify mechanisms of carbapenem resistance. Results MLST results show a high degree of multi-clonal dissemination, with 18 different Sequence Types (STs) identified, including 5 novel. The majority of isolates belonged to International Clone (IC) 2, and carbapenem resistance was detected in 93% of isolates and mediated by blaOXA-23, blaOXA-58, blaNDM-1 and blaVIM-1. We also report the presence of a resistant ST732 (OXA-378) which has been previously identified in migratory birds. Conclusions Multiple highly resistant clones were identified in a Cancer hospital in Cairo. It is vital that clinicians and healthcare workers are aware of the population of A. baumannii present in order to have appropriate treatment and infection control practices.

Clin Microbiol Infect 2012; 18: E446–E451 Abstract Four non‐repetitive, clonally related (ST114), carbapenem‐resistant Acinetobacter baumannii strains isolated in the USA were examined to understand the mechanisms of carbapenem resistance including screening for the presence of an insertion sequence upstream of the blaOXA‐51‐like gene, which could be involved in the control and expression of the antibiotic‐resistance gene. We observed that the main mechanisms of carbapenem resistance were the result of the over‐expression of the blaOXA‐58‐like and the blaOXA‐65 gene, both of which had the presence of ISAba825 upstream of the genes. The importance of this element was shown by isolating plasmid‐cured isogenic strains that had lost the plasmid with the ISAba825‐blaOXA‐58‐like genes but during that same process also lost the chromosomal ISAba825 element present upstream of the blaOXA‐65 gene. A 16‐fold decrease in minimum inhibitory concentration of imipenem and an eight‐fold decrease in the minimum inhibitory concentration of meropenem were seen in the isogenic strains that lost the plasmid. The study presents the first report of ISAba825 simultaneously governing the blaOXA‐65 gene and the blaOXA‐58‐like gene expression and also highlights the importance of this element in carbapenem‐sensitive isogenic strains, which were once carbapenem resistant.