Scandinavia is considered a region with a low prevalence of antimicrobial resistance. However, the number of multidrug-resistant (MDR) Gram-negative bacteria is increasing, including metallo-␤-lactamase (MBL)-producing Pseudomonas aeruginosa. In this study MBL-producing P. aeruginosa isolates identified in Norway (n ‫؍‬ 4) and Sweden (n ‫؍‬ 9) from 1999 to 2007 were characterized. Two international clonal complexes (CC), CC111 (n ‫؍‬ 8) and CC235 (n ‫؍‬ 2), previously associated with MBL-producing isolates, were dominant. CC111 isolates (ST111/229; serotype O12; bla VIM-2 ) included clonally related isolates identified in Skåne County, Sweden (n ‫؍‬ 6), and two isolates associated with importation from Greece and Denmark. In all CC111 isolates, bla VIM-2 was located in integron In59.2 or In59 variants. The two CC235 isolates (ST235/ST230; serotype O11; bla VIM-4 ) were imported from Greece and Cyprus, were possibly clonally related, and carried bla VIM-4 in two different integron structures. Three isolates imported from Ghana (ST233; serotype O6; bla VIM-2 ), Tunisia (ST654; serotype O11; bla VIM-2 ), and Thailand (ST260; serotype O6; bla IMP-14 ) were clonally unrelated. ST233 was part of a new CC (CC233) that included other MBL-producing isolates, while ST654 could also be part of a new CC associated with MBL producers. In the isolates imported from Ghana and Tunisia, bla VIM-2 was part of unusual integron structures lacking the 3 conserved segment and associated with transposons. The bla VIM gene was found to be located on the chromosome in all isolates. Known risk factors for acquisition of MBL were reported for all patients except one. The findings suggest that both import of successful international clones and local clonal expansion contribute to the emergence of MBL-producing P. aeruginosa in Scandinavia.

A total of 61 strains of Staphylococcus aureus and 177 coagulase-negative staphylococcal strains were isolated from the blood of patients with bloodstream infections and from the skin of both children under cancer treatment and human immunodeficiency virus-positive patients. The MIC analyses revealed that 118 isolates (50%) were resistant to quaternary ammonium compound-based disinfectant benzalkonium chloride (BC). The frequencies of resistance to a range of antibiotics were significantly higher among BC-resistant staphylococci than among BC-sensitive staphylococci. Of 78 BC-resistant staphylococcal isolates, plasmid DNA from 65 (83%), 2 (3%), 43 (55%), and 15 (19%) isolates hybridized to qacA or -B (qacA/B), qacC, blaZ, and tetK probes, respectively. The qacA/B and blaZ probes hybridized to the same plasmid in 19 (24%) staphylococcal strains. The plasmids harboring both qacA/B and blaZ genes varied from approximately 20 to 40 kb. The Staphylococcus epidermidis Fol62 isolate, harboring multiresistance plasmid pMS62, contained qacA/B and blaZ together with tetK. Molecular and genetic studies indicated different structural arrangements of blaZ and qacA/B, including variable intergenic distances and transcriptional directions of the two genes on the same plasmid within the strains. The different organizations may be due to the presence of various genetic elements involved in cointegration, recombination, and rearrangements. These results indicate that qac resistance genes are common and that linkage between resistance to disinfectants and penicillin resistance occurs frequently in clinical isolates in Norway. Moreover, the higher frequency of antibiotic resistance among BC-resistant strains indicates that the presence of either resistance determinant selects for the other during antimicrobial therapy and disinfection in hospitals.

Extended spectrum β-lactamase producing Escherichia coli (ESBL-EC) are excreted via effluents and sewage into the environment where they can re-contaminate humans and animals. The aim of this observational study was to detect and quantify ESBL-EC in recreational water and wastewater, and perform a genetic and phenotypic comparative analysis of the environmental strains with geographically associated human urinary ESBL-EC. Recreational fresh-and saltwater samples from four different beaches and wastewater samples from a nearby sewage plant were filtered and cultured on differential and ESBL-selective media. After antimicrobial susceptibility testing and multi-locus variable number of tandem repeats assay (MLVA), selected ESBL-EC strains from recreational water were characterized by whole genome sequencing (WGS) and compared to wastewater and human urine isolates from people living in the same area. We detected ESBL-EC in recreational water samples on 8/20 occasions (40%), representing all sites. The ratio of ESBL-EC to total number of E. coli colony forming units varied from 0 to 3.8%. ESBL-EC were present in all wastewater samples in ratios of 0.56-0.75%. ST131 was most prevalent in urine and wastewater samples, while ST10 dominated in water samples. Eight STs and identical ESBL-EC MLVAtypes were detected in all compartments. Clinical ESBL-EC isolates were more likely to be multidrug-resistant (p<0.001).This study confirms that ESBL-EC, including those that are capable of causing human infection, are present in recreational waters where there is a potential for human exposure and subsequent gut colonisation and infection in bathers. Multidrug-resistant E. coli strains are present in urban aquatic environments even in countries where antibiotic consumption in both humans and animals is highly restricted.

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