Social network analysis of Staphylococcus aureus carriage in a general youth population

Objectives Staphylococcus aureus carriage increases infection risk. We used social network analysis to evaluate whether contacts have the same S. aureus genotype indicating direct transmission, or whether contagiousness is an indirect effect of contacts sharing the same lifestyle or characteristics. Methods The Fit Futures 1 study collected data on social contact among 1038 high school students. S. aureus carriage was determined from two nasal swab cultures and S. aureus genotype from spa-typing of a positive throat swab. Results S. aureus carriage and spa-type were transmitted in the social network (p<0.001). The probability of carriage increased by 5.0% for each S. aureus positive friend. Male sex was associated with a 15% lower risk of transmission compared to female sex, although the prevalence of carriage was higher for men (36% versus 24%). Students with medium physical activity level, medium/high alcohol-use, or normal-weight had higher number of contacts and increased risk of transmission (p<0.002). Conclusions We demonstrate direct social transmission of S. aureus. Lifestyle factors are associated with risk of transmission suggesting indirect social group effects on S. aureus carriage from friends having more similar environmental exposures. The male predominance in carriage is determined by sex-specific predisposing host characteristics as social transmission is less frequent than in females. Information on social network may add to a better understanding of S. aureus epidemiology. Keywords: Staphylococcus aureus, population-based study, spa-type, network analysi

Infection after primary hip arthroplasty: A comparison of 3 Norwegian health registers

Background and purpose: The aim of the present study was to assess incidence of and risk factors for infection after hip arthroplasty in data from 3 national health registries. We investigated differences in risk patterns between surgical site infection (SSI) and revision due to infection after primary total hip arthroplasty (THA) and hemiarthroplasty (HA). Materials and methods: This observational study was based on prospective data from 2005–2009 on primary THAs and HAs from the Norwegian Arthroplasty Register (NAR), the Norwegian Hip Fracture Register (NHFR), and the Norwegian Surveillance System for Healthcare–Associated Infections (NOIS). The Norwegian Patient Register (NPR) was used for evaluation of case reporting. Cox regression analyses were performed with revision due to infection as endpoint for data from the NAR and the NHFR, and with SSI as the endpoint for data from the NOIS. Results: The 1–year incidence of SSI in the NOIS was 3.0% after THA (167/5,540) and 7.3% after HA (103/1,416). The 1–year incidence of revision due to infection was 0.7% for THAs in the NAR (182/24,512) and 1.5% for HAs in the NHFR (128/8,262). Risk factors for SSI after THA were advanced age, ASA class higher than 2, and short duration of surgery. For THA, the risk factors for revision due to infection were male sex, advanced age, ASA class higher than 1, emergency surgery, uncemented fixation, and a National Nosocomial Infection Surveillance (NNIS) risk index of 2 or more. For HAs inserted after fracture, age less than 60 and short duration of surgery were risk factors of revision due to infection. Interpretation: The incidences of SSI and revision due to infection after primary hip replacements in Norway are similar to those in other countries. There may be differences in risk pattern between SSI and revision due to infection after arthroplasty. The risk patterns for revision due to infection appear to be different for HA and THA

Knowledge, attitudes and practices related to self-medication with antimicrobials in Lilongwe, Malawi

Background - The use of antimicrobials is associated with the emergence of antimicrobial resistance (AMR), and self-medication increases the risk of the inappropriate use of antimicrobials. This study aims to describe the knowledge, attitudes, and practices (KAP) regarding self-medication with antimicrobials among residents in Lilongwe, Malawi. Methodology - This study has a cross-sectional, mixed-methods design. We conducted two focus group discussions (n=15) to describe community attitudes towards self-medication with antimicrobials and used a structured questionnaire to collect data on individual KAP regarding self-medication from 105 respondents. Results - Self-medication was common, and the sources of these medicines were market vendors, pharmacies, drugs shared with friends and family and those leftover from previous treatments. The lack of medical supplies, long distances to health facilities, poor attitudes of medical professionals towards patients, and past experience with the disease and treatment are the main factors that influence self-medication. KAP respondents had little knowledge of antimicrobials, their use, or any awareness of AMR. Seventy-four per cent (n=78) were unable to differentiate antimicrobials from other categories of medicines, and 92.4% wrongly responded that antimicrobials could be used to stop a fever. Concerning attitudes towards self-medication, over 54% wrongly believe that antimicrobials are effective in treating common colds. In regard to practice, 53% reported that they would use antimicrobials to treat upper respiratory infections, and 41% agreed that they must complete antibiotic therapy even if they are improving. Logistic regression analysis found that stocking antimicrobials at home for future use significantly promotes self-medication whereas an awareness of AMR would reduce self-medication. Conclusion - Self-medication is a public health risk that needs to be addressed urgently. Findings from this study point to the need for multifaceted interventions

Prevalence of resistance to ampicillin, gentamicin and vancomycin in Enterococcus faecalis and Enterococcus faecium isolates from clinical specimens and use of antimicrobials in five Nordic hospitals.

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldWe determined the species distribution and prevalence of ampicillin resistance, high-level gentamicin resistance (HLGR) and vancomycin resistance among clinical enterococcal isolates from five Nordic laboratories (Bergen, Tromsø, Uppsala, Aarhus and Reykjavik). Isolates represented three different groups: (i) all blood culture isolates from 1999; (ii) consecutive in-patient isolates (maximum 40); and (iii) consecutive outpatient isolates (maximum 40) collected during March to May 2000. Antimicrobial use data were collected at the national and hospital level. A high proportion (31.4%) of Enterococcus faecium was detected among blood culture isolates, in contrast to only 4.2% among isolates from outpatients. Ampicillin resistance was not found in Enterococcus faecalis, in contrast to 48.8% in E. faecium isolates. HLGR rates varied considerably between laboratories (1.1-27.6%). Acquired vancomycin resistance was not detected. There were no significant differences in the prevalences of HLGR between in-patient and outpatient isolates at individual hospitals. A cluster of clonally related ampicillin-resistant and HLGR E. faecium isolates was demonstrated in one of the hospitals. The lowest level of hospital antimicrobial use, the lowest proportion of E. faecium and the lowest prevalence of resistance were observed in Reykjavik.The study showed a relatively low level of resistance in enterococci, as compared with most European countries and the USA. However, there were large differences between hospitals with regard to the relative proportion of E. faecium isolates, their susceptibility to ampicillin and gentamicin, as well as the prevalence of HLGR in E. faecalis isolates. This indicates a potential for further improvement of antibiotic policies, and possibly hospital infection control, to maintain the low resistance levels observed in these countries

Prevalence of resistance to ampicillin, gentamicin and vancomycin in Enterococcus faecalis and Enterococcus faecium isolates from clinical specimens and use of antimicrobials in five Nordic hospitals.

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldWe determined the species distribution and prevalence of ampicillin resistance, high-level gentamicin resistance (HLGR) and vancomycin resistance among clinical enterococcal isolates from five Nordic laboratories (Bergen, Tromsø, Uppsala, Aarhus and Reykjavik). Isolates represented three different groups: (i) all blood culture isolates from 1999; (ii) consecutive in-patient isolates (maximum 40); and (iii) consecutive outpatient isolates (maximum 40) collected during March to May 2000. Antimicrobial use data were collected at the national and hospital level. A high proportion (31.4%) of Enterococcus faecium was detected among blood culture isolates, in contrast to only 4.2% among isolates from outpatients. Ampicillin resistance was not found in Enterococcus faecalis, in contrast to 48.8% in E. faecium isolates. HLGR rates varied considerably between laboratories (1.1-27.6%). Acquired vancomycin resistance was not detected. There were no significant differences in the prevalences of HLGR between in-patient and outpatient isolates at individual hospitals. A cluster of clonally related ampicillin-resistant and HLGR E. faecium isolates was demonstrated in one of the hospitals. The lowest level of hospital antimicrobial use, the lowest proportion of E. faecium and the lowest prevalence of resistance were observed in Reykjavik.The study showed a relatively low level of resistance in enterococci, as compared with most European countries and the USA. However, there were large differences between hospitals with regard to the relative proportion of E. faecium isolates, their susceptibility to ampicillin and gentamicin, as well as the prevalence of HLGR in E. faecalis isolates. This indicates a potential for further improvement of antibiotic policies, and possibly hospital infection control, to maintain the low resistance levels observed in these countries

Effect of prothrombotic genotypes on the risk of venous thromboembolism in patients with and without ischemic stroke: The Tromso Study

Background Patients with ischemic stroke have a transiently increased risk of subsequent venous thromboembolism (VTE). Prothrombotic genotypes may augment VTE risk under conditions of high thrombosis risk related to stroke. Aims To investigate the effect of prothrombotic genotypes in patients with ischemic stroke on the risk of VTE in a population‐based case–cohort study. Methods Cases with incident VTE (n = 664) and a randomly selected age‐weighted subcohort (n = 1817) were sampled from three surveys of the Tromsø Study (1994–2008). Participants were genotyped for ABO (rs8176719), F5 (rs6025), F2 (rs1799963), FGG (rs2066865) and F11 (rs2036914) single‐nucleotide polymorphisms (SNPs). Cox regression models were used to calculate hazard ratios (HRs) for incident VTE according to individual SNPs and categories of risk alleles (5‐SNP score; 0–1, 2, 3–4 and ≥ 5) in participants with and without ischemic stroke. Results There were 192 patients with incident stroke, of whom 43 developed VTE during a median of 15.2 years of follow‐up. The risk alleles of individual SNPs augmented the elevated VTE risk brought about by ischemic stroke. In stroke patients, a one‐category increase in the genetic risk score was associated with a 50% higher relative risk of overall VTE (HR 1.5, 95% confidence interval [CI] 1.3–1.8) and an 80% higher relative risk of provoked VTE (HR 1.8, 95% CI 1.5–2.1). Stroke patients with ≥ 5 risk alleles had a 12‐fold (HR 11.7, 95% CI 4.1–33.3) higher relative risk of VTE than stroke‐free participants with 0–1 risk alleles. Conclusions Prothrombotic genotypes increased the risk of VTE in stroke patients, and the risk increased with an increasing number of risk alleles