Colistin resistance among blood culture isolates at a tertiary care centre in Hungary. (December 2017)

• Record Type: Journal Article
• Authors: Juhász, Emese; Iván, Miklós; Pintér, Eszter; Pongrácz, Júlia; Kristóf, Katalin
• Is Part Of: Journal of global antimicrobial resistance. Volume 11(2017)
• Page Start: 167
• Page End: 170
• Publication Date: 2017-12
• Subjects: Colistin -- Antimicrobial resistance -- Heteroresistance -- mcr-1; Drug resistance -- Periodicals; Drug resistance -- Periodicals; Drug resistance; Periodicals; 616.9041
• DOI: 10.1016/j.jgar.2017.08.002
• Languages: English
• ISSNs: 2213-7165

Abstract

Highlights: First mcr-1 -positive Escherichia coli strain found in Hungary. Prevalence of colistin resistance among enterobacterial blood culture isolates was 0.6%. Colistin-resistant subpopulations were found in 17% of enterobacterial isolates. Prevalence of colistin resistance among P. aeruginosa and A. baumannii was 1.3% and 2.6%, respectively. All Stenotrophomonas maltophilia isolates were resistant to colistin (MIC50 = 64 mg/L). Abstract: Objectives: The emergence of colistin resistance has been detected worldwide in recent years. Whilst colistin susceptibility has been tested in carbapenem resistant Enterobacteriaceae as well as multidrug-resistant Pseudomonas spp. and Acinetobacter spp. during routine laboratory practice, the overall rate of colistin resistance was unknown in our centre. The aim of this retrospective study was to reveal the prevalence of colistin resistance among clinically significant blood culture isolates in two different periods (2010–2011 and 2016) in our laboratory. Methods: Consecutive non-duplicate strains ( n = 776) were screened for colistin resistance using agar plates containing 4 mg/L colistin. Strains cultured on colistin-containing plates were further examined. Minimum inhibitory concentrations (MICs) of colistin-tolerant subcultures and original cultures were determined in parallel by the broth microdilution method. Screening for mcr-1 -mediated colistin resistance was performed by PCR. Results: The rate of colistin resistance was 0.6%, 1.3% and 2.6% in Enterobacteriaceae, Pseudomonas spp. and Acinetobacter spp., respectively; colistin-resistant subpopulations were found in 17%, 27% and 20% of isolates, respectively, with low frequency. Seven colistin-resistant strains were found, among which was an mcr-1 -positive Escherichia coli isolated from a blood sample of a haemato-oncology patient in 2011. All Stenotrophomonas maltophilia isolates were resistant to colistin. Conclusions: The low prevalence of colistin resistance was in accordance with European data. The prevalence of heteroresistance was significantly higher, but the clinical significance of the phenomenon is unclear. We have identified the first mcr-1 -positive E. coli strain in Hungary. mcr-1 has been in Hungary since 2011 but has not yet expanded.