A more virulent strain of the disease is emerging.

BackgroundIn many countries, the reported pertussis has increased despite high vaccination coverage. However, accurate determination of the burden of disease is hampered by reporting artifacts. The infection frequency is more reliably estimated on the basis of the prevalence of high IgG concentrations against pertussis toxin (IgG-Ptx). We determined whether the increase in reported pertussis in the last decade is associated with an increase in the number of infections.Methodology/Principal FindingsIn a cross-sectional population-based serosurveillance study conducted in 2006-07, from a randomly selected age-stratified sample of 7,903 persons, serum IgG-Ptx concentrations were analyzed using a fluorescent bead-based multiplex immuno assay. In 2006-07, 9.3% (95%CI 8.5-10.1) of the population above 9 years of age had an IgG-Ptx concentration above 62.5 EU/ml (suggestive for pertussis infection in the past year), which was more than double compared to 1995-96 (4.0%; 95%CI 3.3-4.7). The reported incidence showed a similar increase as the seroprevalence between both periods.ConclusionsAlthough changes in the vaccination program have reduced pertussis morbidity in childhood, they have not affected the increased infection rate in adolescent and adult pertussis. Indeed, the high circulation of B. pertussis in the latter age-categories may limit the effectiveness of pediatric vaccination.

If immunity to pertussis in parents is maintained or boosted, 35%-55% of infant cases could be prevented. Furthermore, we found that, 1-3 years after vaccination with whole-cell or acellular vaccine, a significant percentage of children are again susceptible for typical pertussis. In the long term, pertussis vaccines and vaccination strategies should be improved to provide longer protection and prevent transmission.

The PAR approach, or the way PAR was applied in the study, was not effective in improving antibiotic prescribing behaviour. The study findings suggest that drawing prescribers' attention to prescribing behaviour and monitoring activities, and increasing use of diagnostic resources may be promising interventions to improve antibiotic prescribing in NHs.

No abstract

Vaccine-serotype disease decreased, but non–vaccine-serotype disease increased.

Extended-spectrum b-lactamases b-lactam resistance Livestock farming Prevalence Risk factors a b s t r a c tObjectives: In the Netherlands there is an ongoing debate regarding environmental health risks of livestock farming for neighbouring residents. This explorative study aims to determine the prevalence of carriage of extended-spectrum b-lactamase and/or plasmid-mediated AmpC-producing Enterobacteriaceae (ESBL/pAmpC-E) in the general population living in a livestock-dense area, and to study associations between determinants, including exposure through contact with animals and the environment, and human carriage of ESBL/pAmpC-E. Methods: A cross-sectional study was performed among 2432 adults (aged 20e72 years) in 12 temporary research centres in the south of the Netherlands, consisting of a questionnaire and analysis of a faecal sample to assess carriage of ESBL/pAmpC-E. Risk factors were analysed using logistic regression. Results: The prevalence for carriage of ESBL/pAmpC-E was 4.5% (109/2432; 95% CI 3.7e5.4) ranging from 1.4% to 10.9% among the research centres. ESBL/pAmpC resistance genes were detected in Escherichia coli and Klebsiella pneumoniae isolates obtained from these 109 persons and the most common ESBLresistance genes were bla CTX-M-15 , bla CTX-M-14/17 and bla CTX-M-1 , originating from 76 participants. Travel in the previous 12 months to Africa, Asia or Latin America (OR 2.82; 95% CI 1.71e4.63), having kept cows for a hobby in the previous 5 years (OR 3.77; 95% CI 1.22e11.64), usage of proton-pump inhibitors (OR 1.84; 95% CI 1.05e3.23), and living within 1000 m of a mink farm (OR 2.26; 95% CI 1.28e3.98) were identified as risk factors. Exposure to poultry was not identified as a risk factor. Conclusions: Overall, living in close proximity to livestock animals and farms does not seem to be a risk factor for carriage of ESBL/pAmpC-E. C.C.H. Wielders, CMI 2017;23:120.e1e120.e8

BackgroundThe epidemiology of carriage of extended-spectrum beta-lactamase-producing (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) in the general population is unknown.AimIn this observational study, the prevalence and risk factors for intestinal ESBL-E and CPE carriage in the Dutch general population were determined. ESBL-E were characterised.MethodsFrom 2014 to 2016, ca 2,000 residents were invited monthly to complete a questionnaire and provide a faecal sample, which was tested for ESBL-E. The first 1,758 samples were also tested for CPE. Risk factors for ESBL-E carriage were identified by multivariable logistic regression analysis. ESBL-E isolates underwent whole genome sequencing.ResultsOf 47,957 individuals invited, 4,177 (8.7%) completed the questionnaire and provided a faecal sample. ESBL-E were detected in 186 (4.5%) individuals, resulting in an adjusted prevalence of 5.0% (95% confidence interval (CI):3.4–6.6%). Risk factors were: born outside the Netherlands (odds ratio (OR): 1.99; 95% CI: 1.16−4.54), eating in restaurants > 20 times/year (OR: 1.70; 95% CI: 1.04−2.76), antibiotic use < 6 months ago (OR: 2.05; 95% CI: 1.05−4.03), swimming in sea/ocean < 12 months ago (OR: 1.63; 95% CI: 1.11−2.39), travelling to Africa (OR: 3.03; 95% CI: 1.23−7.46) or Asia (OR: 2.00; 95% CI: 1.02−3.90) < 12 months ago, and not changing kitchen towels daily (OR: 2.19; 95% CI: 1.24−3.87). The last had the largest population attributable risk (PAR) (47.5%). Eighty-four of 189 (44.4%) ESBL-E isolates carried bla CTX-M-15. Escherichia coli isolates belonged to 70 different sequence types (ST)s, of which ST131 (42/178 isolates; 23.6%) was most prevalent. Associations were observed between IncFIA plasmids and ST131 and bla CTX-M-27, and between IncI1 and ST88 and bla CTX-M-1. No CPE were detected.ConclusionsThe prevalence of ESBL-E carriage in the Netherlands’ community-dwelling population is 5.0%. Identified risk factors were mostly travelling (particularly to Asia and Africa) and kitchen hygiene. CPE were not detected.