Efflux Pump AdeABC Assessment in Acinetobacter baumannii Strains Isolated in a Teaching HospitalClaudia Rizzo, Nadia Marascio*, Emilia Zicca, Grazia Pavia, Angela Quirino, Angelo Giuseppe Lamberti, Maria Carla Liberto and Alfredo Focà
Department of Health Sciences, Institute of Microbiology, School of Medicine, University of Magna Graecia, Viale Europa, Germaneto, 88100 Catanzaro, Italy
- Corresponding Author:
- Nadia Marascio
Department of Health Sciences, Institute of Microbiology
School of Medicine, University of Magna Graecia
Viale Europa, Germaneto, 88100 Catanzaro, Italy
E-mail: [email protected]
Received date: June 13, 2016; Accepted date: July 21, 2016; Published date: July 29, 2016
Citation: Rizzo C, Marascio N, Zicca E, Pavia G, Quirino A, etal. (2016) Efflux Pump AdeABC Assessment in Acinetobacter baumannii Strains Isolated in a Teaching Hospital. J Med Microb Diagn 5:237. doi:10.4172/2161-0703.1000237
Copyright: © 2016 Rizzo C, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Over the past twenty years the worldwide clinically impact of Acinetobacter baumannii (A. baumannii) demonstrated its etiopathogenetic relevance. During a previously retrospective study in a teaching hospital, between January 2011 and February 2015, we observed increasingly infections caused by A. baumannii associated with antibiotic multi-resistance. Tigecycline, the first member of the glycylcycline class, is an effective option for the treatment of such infections even if, due to its increased clinical use, tigecycline resistant isolates have recently emerged. In A. baumannii several mechanisms are associated with a tigecycline decrease susceptibility, among these, expression efflux pump AdeABC and the presence of insertion sequence (IS) in the adeRS operon.About that, we decided to analyze adeB and adeS genes in 24 MDR A. baumannii clinical isolates, selected on the different tigecycline phenotype. The study of adeB and adeS genes was performed by an in-housepolymerase chain reaction (PCR) and by Sanger sequencing method. According to literature adeB and adeS genes were detected in all MDR A. baumannii isolates tested. Therefore our attention has focused on two resistant tigecycline clinical strains (ACI 2313 and ACI 1213), with a MIC value >8. In particular the ACI 2313 strains, showed the presence of an IS in the adeS gene. Then, adeS sequence analysis identified ISAba1 insertion. Moreover, adeB gene expression was evaluated by an in-house SYBR Green I-based real-time RT-PCR. We found an over expression of adeB gene in ACI 2313 strain, according to IS presence on adeS gene, while the lack of adeB overexpression in ACI 1213, still resistant to tigecycline, could be due to different resistance mechanisms.