Invasive infection caused by Klebsiella pneumoniae is a disease affecting patients with high comorbidity and associated with high long-term mortality.

Klebsiella pneumoniae (KP) is after Escherichia coli (EC) the most common gram-negative species causing invasive infections. Herein, we analyzed risk factors and prognosis in invasive infections caused by KP versus EC, in an area with low antimicrobial resistance. Moreover, we compared antimicrobial resistance and relative prevalence of KP and EC (KP/EC-ratio) in different European countries, using EARS-Net data. Adult patients admitted to Karolinska University Hospital 2006-2012 with invasive infection caused by KP (n = 599) were matched regarding sex and age with patients infected by EC. The medical records were retrospectively reviewed. Comorbidity was adjusted for with multivariable analysis. European data were retrieved from the EARS-Net database. No differences were observed in 7- and 30-day mortality between the groups. The 90-day mortality was significantly higher in the KP cohort (26% versus 17%, p<0.001), but not after adjusting for comorbidity. Malignancy was seen in 53% of the patients with KP versus 38% with EC, OR 1.86 (1.34-2.58). A significant increase in the rate of ESBL-production was observed in EC, but not in KP. The KP/EC-ratio remained stable. In contrast, European data showed increasing percentages of isolates non-susceptible to third-generation cephalosporins in EC and KP, and increasing KP/EC-ratio. Invasive infection caused by KP is a disease affecting patients with high comorbidity and associated with high 90-d mortality. The stable KP/EC-ratio and low occurrence of antimicrobial resistance in data from Karolinska University Hospital compared to aggregate data from 20 EARS-Net countries could be related to absence of clonal spread of multidrug-resistant KP.

Frequent acquisition of low-virulence strains of ESBL-producing Escherichia coli in travellers.

OBJECTIVES: International travel is a risk factor for intestinal colonization with ESBL-producing Enterobacteriaceae (EPE). This prospective cohort study focuses on molecular features of and risk factors for travel-acquired EPE. METHODS: Rectal swabs and survey data were collected from 188 Swedes travelling to four regions of high EPE prevalence. Samples were plated onto selective agars. ESBL producers were determined using phenotypic methods. Molecular characterization regarding virulence factors and phylogenetic grouping of ESBL-producing Escherichia coli was done using PCR. Isolates were also screened for the plasmid-mediated colistin resistance gene mcr-1. RESULTS: Among 175 pre-travel EPE-negative participants, 32% were positive upon return. No carbapenemase-producing Enterobacteriaceae were found, but one CTX-M-producing E. coli harboured mcr-1 (travel to Thailand). Most E. coli strains (43.1%) belonged to phylogroup A and were rarely associated with extraintestinal infections and a few (9.2%) expressed uropathogenicity pap genes. During 10-26 months of follow-up, no clinical infections were observed. Colonization rates varied by visited region: the Indian subcontinent, 49.2%; northern Africa, 44.0%; South-East Asia, 19.1%; and Turkey, 9.5%. Travellers' diarrhoea (OR 2.5, P = 0.04) or antimicrobial treatment during the trip (OR 5.9, P = 0.02) were both independent risk factors for EPE colonization. CONCLUSIONS: EPE acquired during travel have seemingly low pathogenicity, possibly indicating a low risk of clinical infection. Pre-travel advice should emphasize avoiding unnecessary antibiotic treatment during travel.

Knowledge and understanding of antibiotic resistance and the risk of becoming a carrier when travelling abroad: a qualitative study of Swedish travellers.

BACKGROUND: Increasing globalisation, with the migration of people, animals and food across national borders increases the risk of the spread of antibiotic-resistant bacteria. To avoid becoming a carrier of antibiotic-resistant bacteria when travelling, knowledge about antibiotic resistance is important. MATERIALS AND METHODS: We aimed to describe the knowledge and understanding of antibiotic-resistant bacteria, and of the risk for becoming a carrier of such bacteria, among Swedish travellers before their travel to high-risk areas. A questionnaire with three open-ended questions was distributed to 100 individuals before departure. RESULTS: The travellers' answers were analysed using content analysis, resulting in the theme 'To be an insecure traveller who takes control over one's own journey'. Our results showed that the travellers were aware of what the term 'antimicrobial resistance' meant, but did not understand its real significance, nor the consequences for the individual nor for society. They also distanced themselves from the problem. Few thought that their travel would entail a risk of becoming a carrier of resistant bacteria. The lack of knowledge caused an uncertainty among the travellers, whom tried to master the situation by using coping strategies. They proposed a number of measures to prevent carriership. The measures were general and primarily aimed at avoiding illness abroad, particularly acute gastro-intestinal infection. CONCLUSIONS: In health care and vaccination clinics, there is a need for improved information for persons intending to travel to high-risk areas, both about the risks of contracting antibiotic-resistant bacteria and about effective preventive measures.

Comparison of disk diffusion, Etest and VITEK2 for detection of carbapenemase-producing Klebsiella pneumoniae with the EUCAST and CLSI breakpoint systems.

The aim of this study was to compare CLSI and EUCAST MIC and disk diffusion carbapenem breakpoints for the detection of carbapenemase-producing Klebsiella pneumoniae. K. pneumoniae strains with known KPC (n = 31) or VIM (n = 20) carbapenemases were characterized by disk diffusion (Oxoid) and Etest (bioMérieux) vs. imipenem, meropenem and ertapenem, and with VITEK2 (bioMérieux, five different cards). Extended-spectrum ß-lactamase (ESBL) testing was performed with VITEK2 (bioMérieux), ESBL combination disks (Becton Dickinson) and the ESBL Etest (bioMérieux). With CLSI and EUCAST MIC breakpoints, respectively, 11 and seven of the strains were susceptible to imipenem, 12 and eight to meropenem, and seven and none to ertapenem. The EUCAST epidemiological cut-off (ECOFF) values for meropenem and ertapenem identified all carbapenemase producers, whereas the imipenem ECOFF failed in five strains. All carbapenemase producers were detected with EUCAST disk diffusion breakpoints for ertapenem and meropenem, and four strains were susceptible to imipenem. CLSI disk diffusion breakpoints characterized 18 (imipenem), 14 (meropenem) and three (ertapenem) isolates as susceptible. When cards with a single carbapenem were used, detection failures with VITEK2 were four for imipenem, none for meropenem and one for ertapenem. Cards containing all three carbapenems had one to two failures. With ESBL combination disks, 21/31 KPC producers and 2/20 VIM producers were positive. With VITEK2, no VIM producers and between none and seven KPC producers were ESBL-positive. All carbapenemase producers were detected with the meropenem MIC ECOFF, or the clinical EUCAST breakpoint for ertapenem. EUCAST disk diffusion breakpoints for meropenem and ertapenem detected all carbapenemase producers. VITEK2 had between none and four failures in detecting carbapenemase producers, depending on the antibiotic card.