Prevalence of healthcare-associated infections in Dutch long-term care facilities from 2009 to 2019.

OBJECTIVE: We assessed trends in the prevalence of healthcare-associated infections (HCAIs) and associated resident and facility characteristics in a national network of long-term care facilities (LTCFs) in the Netherlands from 2009 to 2019. METHODS: Participating LTCFs registered the prevalence of urinary tract infection (UTI), lower respiratory tract infection (LRTI), gastrointestinal infection (GI), bacterial conjunctivitis, sepsis and skin infection, using standardized definitions, in biannual point-prevalence surveys (PPSs). In addition, resident and LTCF characteristics were collected. Multi-level analyses were performed to study changes in the HCAI prevalence over time and to identify resident and LTCF-related risk factors. Analyses were performed for HCAIs overall and for UTI, LRTI and GI combined as these were recorded throughout the period. RESULTS: Overall, 1353 HCAIs were registered in 44,551 residents with a prevalence of 3.0% (95% confidence interval: 2.8-3.1; range between years 2.3-5.1%). When including only UTI, LRTI and GI the prevalence decreased from 5.0% in 2009 to 2.1% in 2019. Multi-variable regression analyses for UTI, LRTI and GI combined indicated that both prolonged participation and calendar time were independently associated with HCAI prevalence; in LTCFs that participated ≥4 years, the HCAI risk was decreased (OR 0.72 (0.57-0.92)) compared with the first year, and the OR per calendar year was 0.93 (0.88-0.97). CONCLUSIONS: Over 11 years of PPS in LTCFs the HCAI prevalence decreased over time. Prolonged participation further reduced the HCAI prevalence, in particular UTIs, despite the increasing age and associated frailty of the LTCF population, illustrating the potential value of surveillance.

Surveillance of infections in long-term care facilities (LTCFs): The impact of participation during multiple years on health care-associated infection incidence.

We studied trends in the incidence of health care-associated infections (HAIs) in LTCFs between 2009 and 2015 and determined the effect of participation in our network. Elder-care physicians reported weekly the number of cases of influenza-like illness, gastroenteritis, (probable) pneumonia, urinary tract infections (UTIs) and all-cause mortality. Trends in the incidence of infection and mortality in relation to LTCF characteristics were calculated using multilevel univariate and multivariate logistic regression. Thirty LTCF participated for 3 years or more, 16 for 2 years and the remaining 12 LTCF for 1 year. During the study period, the median number of beds decreased from 158 to 139, whereas the percentage of residents with private bedrooms increased from 14% to 87%. UTIs were the most frequently reported infections, followed by (probable) pneumonia and gastroenteritis. Adjusted for calendar year and season, we observed a statistically significant decrease in the incidence of influenza-like illness (odds ratio (OR) = 0.8, P < 0.01) and (probable) pneumonia (OR = 0.8, P < 0.01) for each extra year an LTCF participated. Although there are other likely contributors, such as more private rooms and enhanced infection control measures, the decreasing trend of HAI in LTCFs participating in surveillance implies that surveillance is a valuable addition to current strategies to optimise infection control.

Newly identified risk factors for MRSA carriage in The Netherlands.

OBJECTIVES: To elucidate new risk factors for MRSA carriers without known risk factors (MRSA of unknown origin; MUO). These MUO carriers are neither pre-emptively screened nor isolated as normally dictated by the Dutch Search & Destroy policy, thus resulting in policy failure. METHODS: We performed a prospective case control study to determine risk factors for MUO acquisition/carriage (Dutch Trial Register: NTR2041). Cases were MUO carriers reported by participating medical microbiological laboratories to the RIVM from September 1st 2011 until September 1st 2013. Controls were randomly selected from the community during this period. RESULTS: Significant risk factors for MUO in logistic multivariate analysis were antibiotic use in the last twelve months, aOR 8.1 (5.6-11.7), screened as contact in a contact tracing but not detected as a MRSA carrier at that time, aOR 4.3 (2.1-8.8), having at least one foreign parent, aOR 2.4 (1.4-3.9) and receiving ambulatory care, aOR 2.3 (1.4-3.7). Our found risk factors explained 83% of the MUO carriage. CONCLUSIONS: Identifying new risk factors for MRSA carriers remains crucial for countries that apply a targeted screening approach as a Search and Destroy policy or as vertical infection prevention measure.

Staff exchange within and between nursing homes in The Netherlands and potential implications for MRSA transmission.

A recent countrywide MRSA spa-type 1081 outbreak in The Netherlands predominantly affected nursing homes, generating questions on how infection spreads within and between nursing homes despite a low national prevalence. Since the transfer of residents between nursing homes is uncommon in The Netherlands, we hypothesized that staff exchange plays an important role in transmission. This exploratory study investigated the extent of former (last 2 years) and current staff exchange within and between nursing homes in The Netherlands. We relied on a questionnaire that was targeted towards nursing-home staff members who had contact with residents. We found that 17·9% and 12·4% of the nursing-home staff formerly (last 2 years) or currently worked in other healthcare institutes besides their job in the nursing home through which they were selected to participate in this study. Moreover, 39·7% of study participants worked on more than one ward. Our study shows that, in The Netherlands, nursing-home staff form a substantial number of links between wards within nursing homes and nursing homes are linked to a large network of healthcare institutes through their staff members potentially providing a pathway for MRSA transmission between nursing homes and throughout the country.

Detection and epidemiology of carbapenemase producing Enterobacteriaceae in the Netherlands in 2013-2014.

Laboratory detection of carbapenemase-producing Enterobacteriaceae (CPE) is complicated. Screening with MIC values below clinical breakpoints followed by genotypic confirmation is recommended. We evaluated the application of recommended CPE screening and confirmation methods and provide an overview of CPE epidemiology in E. coli and K. pneumoniae in the Netherlands. Data on E. coli and K. pneumoniae isolates with elevated meropenem (>0.25 mg/L) and/or imipenem (>1 mg/L) MIC values in 2013-2014 were selected from the Infectious Disease Surveillance Information System for Antibiotic Resistance. Laboratories were requested to provide additional results of any confirmatory testing performed. Confirmation of elevated carbapenem MIC values using gradient testing was performed in 59.8 % of eligible isolates. Confirmatory testing showed elevated MIC values in 8 % of E. coli and 32 % of K. pneumoniae isolates. The overall proportion of confirmed non-susceptible E. coli and K. pneumoniae was 0.01 % and 0.16 %, respectively. Genotypic confirmation was performed in 61.0 % of isolates with confirmed elevated carbapenem MIC values. A carbapenemase gene was identified in 47 % of E. coli and 65 % of K. pneumoniae isolates. OXA-48, NDM and KPC were the most frequently found carbapenemase genes. The majority (62 %) of CPE isolates was detected through targeted screening. CPE are a rare finding in the Netherlands. Adherence to the national guideline is suboptimal and differs between laboratories, implying a risk of inadequate CPE detection. Since accurate identification of CPE is the first step in prevention of CPE spread, successful implementation of guidelines for testing and reporting of CPE is essential.

Monitoring the spread of meticillin-resistant Staphylococcus aureus in The Netherlands from a reference laboratory perspective.

BACKGROUND: In The Netherlands, efforts to control meticillin-resistant Staphylococcus aureus (MRSA) in hospitals have been largely successful due to stringent screening of patients on admission and isolation of those that fall into defined risk categories. However, Dutch hospitals are not free of MRSA, and a considerable number of cases are found that do not belong to any of the risk categories. Some of these may be due to undetected nosocomial transmission, whereas others may be introduced from unknown reservoirs. AIM: Identifying multi-institutional clusters of MRSA isolates to estimate the contribution of potential unobserved reservoirs in The Netherlands. METHODS: We applied a clustering algorithm that combines time, place, and genetics to routine data available for all MRSA isolates submitted to the Dutch Staphylococcal Reference Laboratory between 2008 and 2011 in order to map the geo-temporal distribution of MRSA clonal lineages in The Netherlands. FINDINGS: Of the 2966 isolates lacking obvious risk factors, 579 were part of geo-temporal clusters, whereas 2387 were classified as MRSA of unknown origin (MUOs). We also observed marked differences in the proportion of isolates that belonged to geo-temporal clusters between specific multi-locus variable number of tandem repeat analysis (MLVA) clonal complexes, indicating lineage-specific transmissibility. The majority of clustered isolates (74%) were present in multi-institutional clusters. CONCLUSION: The frequency of MRSA of unknown origin among patients lacking obvious risk factors is an indication of a largely undefined extra-institutional but genetically highly diverse reservoir. Efforts to understand the emergence and spread of high-risk clones require the pooling of routine epidemiological information and typing data into central databases.

Transmission of MRSA between humans and animals on duck and turkey farms.

OBJECTIVES: The objectives of this study were to estimate the prevalence of MRSA on duck and turkey farms, identify risk factors for human carriage and study transmission between animals and humans. METHODS: On 10 duck and 10 turkey farms, samples were taken from animals, poultry houses, home residences and humans and cultured using pre-enrichment and selective enrichment. MRSA isolates were typed by spa typing and multiple-locus variable number tandem repeat analysis (MLVA) typing. A subset of isolates from animals and humans was investigated using whole-genome mapping. RESULTS: MRSA was found on one duck farm and three turkey farms. On duck farms, all humans were MRSA negative. On turkey farms, 5 of 11 farmers, 2 of 32 family members and 15 of 49 samples from the home residences were MRSA positive. Individuals with daily contact with turkeys were significantly more often MRSA positive than individuals without daily contact. All MRSA isolates belonged to livestock-associated MLVA complex 398, belonged to spa type t011, were negative for Panton-Valentine leucocidin, were mecC negative and were mecA positive. Whole-genome mapping proved a valuable tool to study the transmission of livestock-associated MRSA and showed that on two turkey farms the isolates from the animals and humans were indistinguishable or closely related, indicating transmission. CONCLUSIONS: MRSA carriage in individuals in daily contact with turkeys was significantly higher than that in individuals only living on the farms or than in the general Dutch population. Therefore, persons with a high degree of contact with turkeys have an increased risk of MRSA carriage, and we propose that they should be screened prior to hospitalization in order to decrease the risk of nosocomial transmission.

Extended-spectrum and AmpC ß-lactamase-producing Escherichia coli in broilers and people living and/or working on broiler farms: prevalence, risk factors and molecular characteristics.

OBJECTIVES: The objectives of this study were to: estimate the prevalence of extended-spectrum ß-lactamase (ESBL)- and AmpC ß-lactamase-producing Escherichia coli carriage among broiler farmers, their family members and employees; identify and quantify risk factors for carriage, with an emphasis on contact with live broilers; and compare isolates from humans and broilers within farms with respect to molecular characteristics to gain insight into transmission routes. METHODS: A cross-sectional prevalence study was conducted on 50 randomly selected Dutch broiler farms. Cloacal swabs were taken from 20 randomly chosen broilers. Faecal swabs were returned by 141 individuals living and/or working on 47 farms. ESBL/AmpC-producing E. coli were isolated and, for selected isolates, phylogenetic groups, plasmids and sequence types were determined. Questionnaires were used for risk factor analysis. RESULTS: All sampled farms were positive, with 96.4% positive pooled broiler samples. The human prevalence was 19.1%, with 14.3% and 27.1% among individuals having a low and a high degree of contact with live broilers, respectively. Five pairs of human-broiler isolates had identical genes, plasmid families and E. coli sequence types, showing clonal transmission. Furthermore, similar ESBL/AmpC genes on the same plasmid families in different E. coli sequence types in humans and broilers hinted at horizontal gene transfer. CONCLUSIONS: The prevalence among people on broiler farms was higher than in previous studies involving patients and the general population. Furthermore, an increased risk of carriage was shown among individuals having a high degree of contact with live broilers. The (relative) contribution of transmission routes that might play a role in the dissemination of ESBL/AmpC-encoding resistance genes to humans on broiler farms should be pursued in future studies.

Prevalence of livestock-associated MRSA on Dutch broiler farms and in people living and/or working on these farms.

This study aimed to determine the prevalence and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) on 50 Dutch broiler farms. Of 145 persons living and/or working on these farms, eight tested positive for MRSA (5.5%). Investigation of 250 pooled throat samples of broilers and 755 dust samples resulted in four farms where MRSA-positive samples were present (8.0%). All isolates belonged to the CC398 complex. Living and/or working on a MRSA-positive farm was a risk for MRSA carriage; 66.7% of people on positive farms were MRSA positive vs. 1.5% on negative farms (P<0.0001). Due to the low number of positive farms and persons, and high similarity in farm management, it was impossible to draw statistically valid conclusions on other risk factors. For broiler farming, both farm and human MRSA prevalence seem much lower than for pig or veal farming. However, MRSA carriage in people living and/or working on broiler farms is higher compared to the general human population in The Netherlands (5.5% vs. <0.1%). As broiler husbandry systems are not unique to The Netherlands, this might imply that people in contact with live broilers are at risk for MRSA carriage worldwide.

Prevalence and determinants associated with healthcare-associated infections in long-term care facilities (HALT) in the Netherlands, May to June 2010.

HAIs (healthcare-associated infections) are likely to become an increasing public health problem. Therefore, a point-prevalence study called HALT (Healthcare-associated infections in long-term-care facilities) was set up by the European Centre for Disease Prevention and Control to determine the prevalence, antibiotic use and determinants associated with HAIs. In the Netherlands, 10 nursing homes (in total 1,429 elderly residents) participated in the study between May and June 2010. Risk and protective factors were determined by calculating relative risks (RRs) and performing multilevel Poisson regression. An overall infection prevalence of 2.8% was found and 3.5% of the residents used antibiotics. Residents' characteristics such as the presence of pressure wounds (RR: 2.58; 95% CI:1.04-6.39) and other wounds (RR: 5.70; 95% CI: 2.99-10.86) were risk factors for an HAI, whereas being male (RR: 0.43; 95% CI: 0.21-0.91) was protective. Nursing home characteristics, such as the percentage of shared rooms ( ≥ 2%) (RR: 0.49; 95% CI: 0.39-0.62) and percentage of incontinent residents (≥ 3%) (RR: 0.72; 95% CI: 0.61-0.85) were protective determinants in a multivariate analysis. Special attention is therefore needed for female residents and residents with pressure and other wounds for the prevention of HAIs in Dutch nursing homes.

Emergence of MRSA of unknown origin in the Netherlands.

The Netherlands is known for its low methicillin-resistant Staphylococcus aureus (MRSA) prevalence. Yet MRSA with no link to established Dutch risk factors for acquisition, MRSA of unknown origin (MUO), has now emerged and hampers early detection and control by active screening upon hospital admittance. We assessed the magnitude of the problem and determined the differences between MUO and MRSA of known origin (MKO) for CC398 and non-CC398. National MRSA Surveillance data (2008-2009) were analysed for epidemiological determinants and genotypic characteristics (Panton-Valentine leukocidin, spa). A quarter (24%) of the 5545 MRSA isolates registered were MUO, i.e. not from defined risk groups. There are two genotypic MUO groups: CC398 MUO (352; 26%) and non-CC398 MUO (998; 74%). CC398 MUO needs further investigation because it could suggest spread, not by direct contact with livestock (pigs, veal calves), but through the community. Non-CC398 MUO is less likely to be from a nursing home than non-CC398 MKO (relative risk 0.55; 95% CI 0.42-0.72) and Panton-Valentine leukocidin positivity was more frequent in non-CC398 MUO than MKO (relative risk 1.19; 95% CI 1.11-1.29). Exact transmission routes and risk factors for non-CC398 as CC398 MUO remain undefined.

Prevalence of methicillin-resistant Staphylococcus aureus and risk factors for carriage in Dutch hospitals.

To evaluate the actual burden of methicillin-resistant Staphylococcus aureus and determine risk factors for carriage and infection, we performed a prevalence survey with a nested case-control study among inpatients in Dutch hospitals. The prevalence of carriage was 0.94 cases per 1,000 inpatients, and the prevalence of infection was 0.21 cases per 1,000 inpatients. Professional contact with livestock and a stay in a foreign hospital were associated with carriage.

Prevalence of livestock-associated MRSA in broiler flocks and risk factors for slaughterhouse personnel in The Netherlands.

To determine methicillin-resistant Staphylococcus aureus (MRSA) carriage in poultry and slaughterhouse personnel, 40 Dutch broiler flocks, in six slaughterhouses and 466 personnel were sampled. Of the employees, 26 were positive (5.6%), indicating a higher risk of exposure when compared to the general Dutch population (0.1%). This risk was significantly higher for personnel having contact with live animals (5.2%) - especially hanging broilers on the slaughterline (20.0%) - than for all other personnel (1.9%). Conventional electric stunning conferred a significantly higher risk of MRSA carriage for employees than CO2 stunning (9.7% vs. 2.0%). A total of 405 broilers were sampled upon their arrival at the slaughterhouse, of which 6.9% were positive. These broilers originated from 40 Dutch slaughter flocks of which 35.0% were positive. MRSA contamination in the different compartments of slaughterhouses increased during the production day, from 8% to 35%. Of the 119 MRSA isolates, predominantly livestock-associated MRSA ST398 was found, although 27.7% belonged to ST9 (spa type t1430). There is an increased risk of MRSA carriage in personnel working at broiler slaughterhouses, particularly those having contact with live animals.

Molecular characterisation of PFGE non-typable methicillin-resistant Staphylococcus aureus in The Netherlands, 2007.

In 2007 in The Netherlands, 30% of all human isolates of methicillin-resistant Staphylococcus aureus (MRSA) sent to the National Institute for Public Health and the Environment could not be typed by pulsed-field gel electrophoresis (non-typable (NT)-MRSA). Molecular characterisation of the NT-MRSA isolates revealed 27 different spa types and two distinct SCCmec types, type IV and V. All NT-MRSA isolates were closely related based on spa and multi-locus sequence typing and belonged to the ST398 lineage. The rapid increase of NT-MRSA (ST398) isolates over the last years shows the importance of this relatively new clonal lineage.

Methicillin-resistant Staphylococcus aureus in people living and working in pig farms.

We compared the prevalence of human and animal methicillin-resistant Staphylococcus aureus (MRSA) at pig farms in The Netherlands, and related this to individual and farm-level characteristics. More than half of the farms investigated (28/50) had MRSA in pigs or stable dust and about one third (15/50) of person(s) were identified as MRSA carriers. Human carriage was found only on farms with MRSA-positive pigs or dust. MRSA strains in human samples were the same spa-type as found in pigs and all were not typable by pulsed-field gel electrophoresis (NT-MRSA). Multivariate analyses showed that risk factors for human MRSA carriage were: working in pig stables (OR 40, 95% CI 8-209) and the presence of sows and finishing pigs (OR 9, 95% CI 3-30). Veterinary sample collectors sampling the pigs showed transient MRSA carriage only during the day of the farm visit. Working in pig stables with MRSA-positive pigs poses a high risk for acquiring MRSA, increasingly so when contact with live pigs is more intensive or long lasting.

Suggestibility in hypochondriacal patients and healthy control subjects. An experimental case-control study.

This study examined suggestibility to bodily sensations in hypochondriacal patients and healthy subjects. Both groups participated in an experiment in which electrical current was announced but not delivered. Suggestibility was measured by the number of responses and by response latencies. The authors hypothesized that the hypochondriacal patients would be more easily influenced by the expectation of a forthcoming stimulus, leading to higher and quicker "stimulus detection" rates than those experienced by the healthy subjects. In contrast to these expectations, the healthy subjects showed higher response frequencies and lower response latencies. Thus, the hypochondriacal patients appeared to be less influenced by the expectation that was raised. The theoretical and clinical implications of the results are discussed.