Biofilm-Forming Ability and Clonality in Acinetobacter baumannii Strains Isolated from Urine Samples and Urinary Catheters in Different European Hospitals
Biofilm formation has been associated with the persistence of Acinetobacter baumannii in hospital settings and its propensity to cause infection. We investigated the adhesion ability and clonality of 128 A. baumannii isolates recovered from urine and urinary catheters of patients admitted to 5 European hospitals during 1991–2013.
Isolates identification was confirmed by rpoB sequencing and by the presence of blaOXA-51. The presence of carbapenemases was detected by PCR. Clonality was determined by Sequence Group (SG) identification, Pulsed field gel electrophoresis (PFGE) and Multilocus sequence typing. Adhesion ability was defined by quantitative biofilm production assay and biofilms were characterized by Confocal Laser Microscopy and Scanning Electron Microscopy.
The 128 isolates, either resistant (85.9%) or susceptible (14.1%) to carbapenems, and belonging to 50 different PFGE types and 24 different STs, were distributed among SG1 (67.2%), SG2 (10.2%) and other allelic profiles (22.7%). ST218 was the most frequent ST, corresponding to 54,5% of the isolates collected between 2011 and 2013. Among the 109 isolates showing resistance to at least 1 carbapenem, 55% revealed the presence of an acquired carbapenem-hydrolyzing class D - lactamases (CHDL): blaOXA-23 were the most frequent gene detected from 2008 onwards (75%). Among all the clinical isolates, 42.2% were strong biofilm producers, with the older isolates having the highest adhesion ability. Most isolates recovered later, belonging to ST218 and harbouring blaOXA-23, were homogeneously less adhesive.
An evolution towards a decrease in adhesion ability and a CHDL content change was observed along the years in several European countries.
KeywordsAcinetobacter baumannii Clonality Biofilm Urinary infection Carbapenem resistance
We thank (in alphabetical order) Edoardo Carretto (Clinical Microbiology Laboratory, IRCCS - Arcispedale Santa Maria Nuova, Reggio Emilia, Italy), Anna Giammanco (Department of Sciences for Health Promotion and Mother-Child Care “G.D’Alessandro”, Palermo, Italy), Ivana Goic-Barisic (Clinical Department of Microbiology and Parasitology, Split University Hospital and School of Medicine, Split, Croatia), Veronica Hola (Institute for Microbiology Masaryk, University Pekarska, Brno, Czech Republic), Piero Marone (Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy), Maria Teresa Mascellino (Dip. Sanita’ Pubblica E Malattie Infettive, Sapienza University, Rome, Italy), Harald Seifert (Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany), Sonja Swidsinski (Department of Microbiology, Vivantes Hospital, Berlin, Germany) for kindly providing us with Acinetobacter baumannii clinical isolates. Italian authors are also indebted to Antonino Salvia, Director of Medical Services of the Fondazione Santa Lucia in Rome, for the useful information and advice on the clinical issues of this research.
The authors declare no conflicts of interest.
This study was partially funded by the ESCMID Study Group for Biofilms with the Research Grant 5833 assigned to Gianfranco Donelli and Luisa Peixe.
- CLSI. Performance standards for antimicrobial susceptibility testing; twentieth informational supplement (2011) CLSI document M100-S21. Clinical and Laboratory Standards Institute, WayneGoogle Scholar
- Mosqueda N, Gato E, Roca I, López M, de Alegría CR, Fernández Cuenca F, Martínez-Martínez L, Pachón J, Cisneros JM et al (2014) Characterization of plasmids carrying the blaOXA-24/40 carbapenemase gene and the genes encoding the AbkA/AbkB proteins of a toxin/antitoxin system. J Antimicrob Chemother 69:2629–2633CrossRefGoogle Scholar
- Principe L, Piazza A, Giani T, Bracco S, Caltagirone MS, Arena F, Nucleo E, Tammaro F, Rossolini GM, et al; AMCLI-CRAb Survey Participants (2014) Epidemic diffusion of OXA-23-producing Acinetobacter baumannii isolates in Italy: results of the first cross-sectional countrywide survey. J Clin Microbiol 52:3004–3010CrossRefGoogle Scholar
- Rodríguez-Baño J, Martí S, Soto S, Fernández-Cuenca F, Cisneros JM, Pachón J, Pascual A, Martínez-Martínez L, McQueary C, et al; Spanish Group for the Study of Nosocomial Infections (GEIH) (2008) Biofilm formation in Acinetobacter baumannii: associated features and clinical implications. Clin Microbiol Infect 14:276–278CrossRefGoogle Scholar
- Seifert H, Dolzani L, Bressan R, van der Reijden T, van Strijen B, Stefanik D, Heersma H, Dijkshoorn L (2005) Standardization and interlaboratory reproducibility assessment of pulsed-field gel electrophoresis-generated fingerprints of Acinetobacter baumannii. J Clin Microbiol 43:4328–4335CrossRefGoogle Scholar