Carriage of ESBL/AmpC-producing or ciprofloxacin non-susceptible Escherichia coli and Klebsiella spp. in healthy people in Norway
Ulstad et al. Antimicrobial Resistance and Infection Control
Carriage of ESBL/AmpC-producing or ciprofloxacin non-susceptible Escherichia coli and Klebsiella spp. in healthy people in Norway
Charlotte R. Ulstad 0
Margrete Solheim 0
Sophie Berg 0
Morten Lindbaek 1
Ulf R. Dahle 0
Astrid L. Wester 0
0 Domain for Infection Control and Environmental Health, Norwegian Institute of Public Health , Oslo , Norway
1 Institute of Health and Society, University of Oslo , Oslo , Norway
Background: Asymptomatic carriage has been recognised as an important risk factor for infection caused by antibiotic resistant bacteria. A 14% global prevalence of Extended-Spectrum Beta-lactamase (ESBL) carriage was recently reported, but large intra-and interregional variations were observed. We investigated the faecal carriage rates of ESBL-, AmpC-producing and ciprofloxacin non-susceptible Escherichia coli and Klebsiella spp. in healthy Norwegians. Methods: Rectal samples were obtained from 284 volunteers, together with demographic data and information on recent travel history. The rectal samples were screened by selective plating and E. coli and Klebsiella spp. identified using MALDI-TOF. Phenotypic and molecular characterization of resistant isolates was also performed. Results: ESBL- or AmpC-producing E. coli and Klebsiella spp. were isolated from 4.9% and 3.2% of the study population, respectively. Carriage of ciprofloxacin non-susceptible isolates was detected in 9.9% of the volunteers. Molecular typing of ESBL/plasmid-mediated AmpC (pAmpC)-producing isolates suggested an allodemic situation rather than the dissemination of a specific clone in the Norwegian community. In concurrence with previous findings, travel to South-East Asia was associated with increased risk of carrying resistant E. coli or Klebsiella spp., highlighting the contribution of factors such as increased global mobility in erasing the boundaries between healthcare and community settings when it comes to spread of resistant bacteria. Conclusions: Overall, our study recognised Norway as a low-incidence country for faecal carriage of resistant bacteria among healthy individuals. Furthermore, our work denoted the importance of healthy humans as a reservoir for transmission of antibiotic resistant E. coli and Klebsiella spp.
Faecal carriage; ESBL; Ciprofloxacin; Norway; Escherichia coli; Klebsiella
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Background
The prevalence of antimicrobial resistance (AMR) is
increasing worldwide, and represents a serious threat to the
global health [1, 2]. Enterobacteriaceae is one of the most
common causes of both nosocomial and community
acquired bacterial infections [3]. Traditionally, betalactam
antibiotics and fluoroquinolones have been the treatment of
choice for infections originating from Gram negative bacilli
[2, 4]. However, the emergence of extended-spectrum
betalactamases (ESBL and plasmid-mediated AmpC; pAmpC)
and different mechanisms of ciprofloxacin resistance have
rendered such infections notoriously challenging to treat
and cure [4, 5].
Faecal carriage of ESBL probably represents the most
important reservoir for infections with ESBL-producing
Enterobacteriaceae [6, 7]. However, differences in the
prevalence of gut colonization with ESBL-producing
bacteria are observed both between and within regions,
and the rates of colonization with ESBL-producing
bacteria are generally increasing [8, 9]. Overall, an annual
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worldwide increase of 5.38% has been suggested [8].
CTX-M is the dominating ESBL-variant in communities
worldwide [9]. Among clinical isolates found in
Scandinavia, the predominant genotype is blaCTX-M-15 [10–12].
Data on community carriage of pAmpC is more limited,
but it represents an important mechanism of resistance
to extended-spectrum cephalosporins [13], although less
common than ESBLs [14].
Reports on faecal colonization of ciprofloxacin-resistant
Enterobacteriaceae are often based on the proportions
of quinolone resistance in ESBL screening isolates,
rather than screening for ciprofloxacin resistance in the
first place. These observations may therefore be biased
due to a significant association between ESBL production
and ciprofloxacin resistance [15]. Prevalence studies in
which ciprofloxacin resistance has been the primary
criterion for selection are less frequent. The most recent data
available corresponds to pre-travel colonization rates (...truncated)