Co-occurrence of aminoglycoside and β-lactam resistance mechanisms in aminoglycoside- non-susceptible Escherichia coli isolated in the Zurich area, Switzerland

• Published in: International journal of antimicrobial agents Vol. 56; no. 1; p. 106019
• Main Authors: Bodendoerfer, Elias, Marchesi, Martina, Imkamp, Frank, Courvalin, Patrice, Böttger, Erik C., Mancini, Stefano
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.07.2020
• Subjects: Aminoglycosides; Aminoglycosides - pharmacology; Anti-Bacterial Agents - pharmacology; anti-infective agents; area; beta-Lactamases - biosynthesis; beta-Lactamases - genetics; Beta-lactams; beta-Lactams - pharmacology; Co-occurrence of antibiotic resistance; Co-resistance; Drug Resistance, Bacterial - genetics; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - drug therapy; Escherichia coli Infections - epidemiology; Genome, Bacterial - genetics; genotype; Humans; Infectious Disease; Microbial Sensitivity Tests; resistance genes; resistance mechanisms; strains; Switzerland; Switzerland - epidemiology; therapeutics; Whole Genome Sequencing; Switzerland; Aminoglycosides; Beta-lactams; Whole genome sequencing; Escherichia coli; Co-occurrence of antibiotic resistance; Co-resistance
• ISSN: 0924-8579; 1872-7913; 1872-7913
• DOI: 10.1016/j.ijantimicag.2020.106019

•Aminoglycoside resistance in Escherichia coli is due to a broad variety of mechanisms•Aminoglycoside and β-lactam resistance frequently co-occur in Escherichia coli•Combination therapy for severe infections with Enterobacteriaceae requires careful consideration The co-occurrence of aminoglycoside and β-lactam resistance was assessed in 3358 consecutive Escherichia coli clinical isolates collected in 2014 in the greater Zurich area, Switzerland. Non-susceptibility to at least one of the tested aminoglycosides was observed in 470/3358 E. coli strains (14%). In strains categorized as broad-spectrum β-lactamase (BSBL)-producers (1241/3358 isolates), extended-spectrum β-lactamase (ESBL)-producers (262/3358) and AmpC-producers (66/3358), resistance to aminoglycoside was found in 23%, 52% and 20% of the isolates, respectively. In contrast, aminoglycoside-susceptible strains were rarely resistant to β-lactams (33/1777, 1.9%). The genomes of 439 aminoglycoside-resistant E. coli were sequenced and aminoglycoside and β-lactam genotypes were analysed. The most prevalent aminoglycoside resistance genes were aph(3’)-Ia (133 strains, 30.3%), aac(3)-IId (100 strains, 22.8%), and aac(6’)-Ib-cr (52 strains, 11.8%). The most frequent associations with β-lactam resistance genes were aph(3’)-Ia or aac(3)-IId with blaTEM-1 (94 and 72 strains, respectively), and aac(3)-IIa/aac(6’)-Ib-cr with blaCTX-M-15/blaOXA-1 (23 strains). These results indicate a frequent association of aac(3) and aph(3’) genotypes with BSBL production, and a frequent co-occurrence of aac(6’) genes with ESBL production. The high rate of co-occurrence of aminoglycoside resistance and β-lactamase production must be considered in combination therapy.