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Aims: To investigate the prevalence of β-lactamase genes in domestic washing machines and dishwashers, and the decontamination efficacy of laundering., Methods and Results: For the first investigation, swab samples from washing machines (n = 29) and dishwashers (n = 24) were analysed by real-time quantitative PCR to detect genes encoding β-lactamases. To test the impact of laundering on resistant bacteria, cotton test swatches were artificially contaminated with susceptible and resistant strains of Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus within a second investigation. They were washed in a domestic washing machine with or without activated oxygen bleach (AOB)-containing detergent at 20-50°C. β-Lactamase genes (most commonly of the AmpC- and OXA-type) were detected in 79% of the washing machines and in 96% of the dishwashers and Pseudomonadaceae dominated the microbiota. The level of bacterial reduction after laundering was ≥80% for all Ps. aeruginosa and Kl. pneumoniae strains, while it was only 37-61% for the methicillin-resistant Staph. aureus outbreak strain. In general, the reduction was tendentially higher for susceptible bacteria than for the resistant outbreak strains, especially for Staph. aureus., Conclusions: β-Lactamase genes seem to be frequently present in domestic appliances and may pose a potential risk for cross-contamination and horizontal transfer of genes encoding resistance against clinically important β-lactams. In general, higher temperatures and the use of AOB can improve the reduction of antibiotic-resistant bacteria, including Staph. aureus which appears to be less susceptible to the decontamination effect of laundering., Significance and Impact of This Study: Data on the presence of antibiotic-resistant bacteria in the domestic environment are limited. This study suggests that β-lactamase genes in washing machines and dishwashers are frequent, and that antibiotic-resistant strains are generally more resistant to the used washing conditions., (© 2017 The Society for Applied Microbiology.)

In a primary care study of urinary tract infections (UTIs) performed 2008 in Uppsala County, Sweden, 43% of the patients were culture negative. In order to investigate the background to the observed overdiagnosis of UTI, study invitations were sent to the previously included patients. A total of 256 patients (88% women) approved to participate. Patient charts and recorded laboratory data were reviewed. Two or more of the cardinal symptoms were reported in 53% of the women and in 19% of the men. A dipstick test was performed in 93% of the consultations. The highest positive predicted values in women had a positive nitrite test (95%, 95% CI 87; 99) and dysuria in combination with urgency (81%, 95% CI 72; 88). Seventy-one percent of the women who fulfilled the symptom criteria received an antibiotic prescription directly, 87% of these had a positive culture. The drug of choice was pivmecillinam for women (51%) and quinolones (50%) for men. The treatment duration was too long for the women; 68% were treated for ≥7 days. In conclusion, the adherence to national guidelines/recommendations was inadequate. To reduce the selection of multiresistant bacteria, an improvement of the use of diagnostic criteria/tools and antibiotic drugs in primary care is necessary., (© 2017 APMIS. Published by John Wiley & Sons Ltd.)