Abstract
This study determined the antibiotic susceptibility profile and genetic mechanisms of β-lactam resistance in 27 clinical strains of Acinetobacter baumannii isolated at the University Hospitals of Geneva, Switzerland. The antimicrobial susceptibility testing was performed using Etest and the disc diffusion method in accordance with CLSI guidelines. All of the strains were defined as multi-drug resistant (MDR) and were susceptible to colistin and moderately susceptible to tigecycline. Uniplex PCR assays were used to detect the following β-lactamase genes: four class D carbapenem-hydrolysing oxacillinases (blaOXA-51, blaOXA-23, blaOXA-24 and blaOXA-58), four class B metallo-β-lactamases genes (blaIMP, blaVIM, blaSPM and blaNDM) and two class A carbapenemases (blaKPC and blaGES). All of the strains were positive for blaOXA-51 (intrinsic resistance), 14/27 strains carried blaOXA-23, 2/27 strains carried a blaOXA-24-like gene, and 4/27 strains had a blaOXA-58 gene. blaGES-11 was found in three strains, and NDM-1-harbouring strains were identified in three patients. All of the A. baumannii isolates were typed by rep-PCR (DiversiLab) and excluded any clonality. Altogether, this analysis suggests a very high genetic diversity of imported MDR A. baumannii.
Highlights
Acinetobacter baumannii, a Gram-negative opportunistic coccobacilli, has emerged globally in healthcare institutions because it is hard to eradicate, most likely because it is resistant to desiccation and to ultraviolet and chemical sanitizers [1]
Cherkaoui et al Ann Clin Microbiol Antimicrob (2015) 14:42 date, infections associated with A. baumannii New Delhi metallo-β-lactamase-1 (NDM-1)-positive strains have been reported in several countries, including Switzerland [13, 14]
Antimicrobial susceptibility All of the isolates analysed in this study were resistant to amikacin, ciprofloxacin, ceftazidime, and piperacillintazobactam
Summary
Acinetobacter baumannii, a Gram-negative opportunistic coccobacilli, has emerged globally in healthcare institutions because it is hard to eradicate, most likely because it is resistant to desiccation and to ultraviolet and chemical sanitizers [1]. Of the multidrug-resistant organisms, the highly resistant Acinetobacter spp. isolates deserve special mention. Acinetobacter spp. may develop resistance to Cherkaoui et al Ann Clin Microbiol Antimicrob (2015) 14:42 date, infections associated with A. baumannii New Delhi metallo-β-lactamase-1 (NDM-1)-positive strains have been reported in several countries, including Switzerland [13, 14]. An NDM-2 variant (Pro-to-Ala substitution at position 28) was recently described [17]. This allele was first found in a multidrug-resistant A. baumannii strain isolated from a German patient previously hospitalised in Egypt and subsequently isolated in Israel [12, 17, 18]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call