Universal risk assessment upon hospital admission for screening of carriage with multidrug-resistant micro-organisms in a Dutch tertiary care centre.

BACKGROUND: In Dutch hospitals a six-point questionnaire is currently mandatory for risk assessment to identify carriers of multidrug-resistant organisms (MDROs) at the time of hospitalization. Presence of one or more risk factors is followed by pre-emptive isolation and microbiological culturing. AIM: To evaluate the yield of the universal risk assessment in identifying MDRO carriers upon hospitalization. METHODS: A cross-sectional study was performed using routine healthcare data in a Dutch tertiary hospital between January 1st, 2015 and August 1st, 2019. MDRO risk assessment upon hospitalization included assessment of: known MDRO carriage, previous hospitalization in another Dutch hospital during an outbreak or a foreign hospital, living in an asylum centre, exposure to livestock farming, and household membership of a meticillin-resistant Staphylococcus aureus carrier. FINDINGS: In total, 144,051 admissions of 84,485 unique patients were included; 4480 (3.1%) admissions had a positive MDRO risk assessment. In 1516 (34%) admissions microbiological screening was performed, of which 341 (23%) yielded MDRO. Eighty-one patients were categorized as new MDRO carriers, as identified through MDRO risk assessment, reflecting 0.06% (95% confidence interval: 0.04-0.07) of all admissions and 1.8% (1.4-2.2) of those with positive risk assessment. As a result, the number of 'MDRO risk assessments needed to perform' and individual 'MDRO questions needed to ask' to detect one new MDRO carrier upon hospitalization were 1778 and 10,420, respectively. CONCLUSION: The yield of the current strategy of MDRO risk assessment upon hospitalization is limited and it needs thorough reconsideration.

Risk factors for the acquisition of OXA-48-producing Enterobacteriaceae in a hospital outbreak setting: a matched case-control study.

OBJECTIVES: In the context of a large outbreak of OXA-48-producing Enterobacteriaceae (OXA-E) in a Dutch hospital we determined risk factors for acquisition of OXA-E. PATIENTS AND METHODS: A matched case-control study was performed in which cases (culture positive for OXA-E) were matched 1:3 to controls (culture negative for OXA-E) based on hospital ward, index date (±1 week) and time exposed in the hospital (best match). Stratified analyses were performed for patients with OXA-E producing and not producing ESBL. Potential risk factors included age, gender, surgery and ICU admission within 30 days preceding the index date, presence of comorbidities and in-hospital antibiotic treatment within 30 days preceding the index date. Data analysis was performed using multivariable conditional logistic regression with Firth correction. RESULTS: In total, 73 cases were matched to 211 controls. In the multivariable conditional logistic regression model, male gender (OR 2.63, 95% CI 1.25-5.53), age (per year increase, OR 1.03, 95% CI 1.00-1.05) and use of fluoroquinolones within 30 days preceding the index date (OR 2.98, 95% CI 1.06-8.41) were risk factors for acquisition of OXA-E. In the stratified multivariable conditional logistic regression model, quinolone use was a risk factor for the acquisition of ESBL-producing OXA-E and surgery was a risk factor for the acquisition of non-ESBL-producing OXA-E. CONCLUSIONS: During a large, hospital-wide OXA-E outbreak, male gender, age and previous use of fluoroquinolones were risk factors for acquisition of OXA-E. These findings may help in optimizing screening and isolation strategies in future OXA-E outbreaks.

Raman spectroscopy-based identification of nosocomial outbreaks of the clonal bacterium Escherichia coli.

DNA-based techniques are frequently used to confirm the relatedness of putative outbreak isolates. These techniques often lack the discriminatory power when analyzing closely related microbes such as E. coli. Here the value of Raman spectroscopy as a typing tool for E. coli in a clinical setting was retrospectively evaluated.

Successful control of a hospital-wide outbreak of OXA-48 producing Enterobacteriaceae in the Netherlands, 2009 to 2011.

On 31 May 2011, after notification of Klebsiella pneumoniae (KP)(OXA-48;CTX-M-15) in two patients, nosocomial transmission was suspected in a Dutch hospital. Hospital-wide infection control measures and an outbreak investigation were initiated. A total of 72,147 patients were categorised into groups based on risk of OXA-48 colonisation or infection, and 7,527 were screened for Enterobacteriaceae(OXA-48) by polymerase chain reaction (PCR). Stored KP isolates (n=408) were retrospectively tested for OXA-48 and CTX-M-1 group extended-spectrum beta-lactamases (ESBL). 285 KP isolates from retrospective and prospective patient screening were genotyped by amplified fragment length polymorphism (AFLP). 41 isolates harbouring different Enterobacteriaceae species were analysed by plasmid multilocus sequence typing (pMLST). No nosocomial transmission of Enterobacteriaceae(OXA-48) was detected after 18 July 2011. Enterobacteriaceae(OXA-48) were found in 118 patients (KP (n=99), Escherichia coli (n=56), ≥1 Enterobacteriaceae(OXA-48) species (n=52)), of whom 21 had clinical infections. 39/41 (95%) of OXA-48 containing plasmids were identical in pMLST. Minimum inhibitory concentrations (MICs) of KP(OXA-48) and E. coli(OXA-48) for imipenem and meropenem ranged from ≤1 to ≥16 mg/L, and 153/157 (97%) had MIC >0.25 mg/L for ertapenem. AFLP identified a cluster of 203 genetically linked isolates (62 KP(OXA-48;CTX-M15); 107 KP(CTX-M-15); 34 KP(OXA-48)). The 'oldest' KP(CTX-M-15) and KP(OXA-48) clonal types originated from February 2009 and September 2010, respectively. The last presumed outbreak-related KP(OXA-48) was detected in April 2012. Uncontrolled transmission of KP(CTX-M-15) evolved into a nosocomial outbreak of KP(OXA-48;CTX-M15) with large phenotypical heterogeneity. Although the outbreak was successfully controlled, the contribution of individual containment measures and of the hospital relocating into a new building just before outbreak notification was impossible to quantify.

Sustained low prevalence of meticillin-resistant Staphylococcus aureus upon admission to hospital in The Netherlands.

The prevalence of meticillin-resistant Staphylococcus aureus (MRSA) carriage at hospital admission in The Netherlands was 0.03% in 1999-2000. The aim of the present study was to assess whether the prevalence of MRSA carriage in The Netherlands has changed over the last few years. In five Dutch hospitals, 6496 unique patients were screened for nasal S. aureus carriage at hospital admission by microbiological culture between 1 October 2005 and 7 June 2007. In total, 2036 of 6496 (31.3%) patients carried S. aureus in their nose, and seven of 6496 (0.11%) patients were nasal carriers of MRSA. Compared with 1999-2000, the prevalence of MRSA carriage in the Dutch population at hospital admission has increased more than three fold; however, this increase was not significant (P=0.06, Fisher's exact test). This prevalence is still among the lowest in the world, probably as a result of the stringent Dutch infection control policy, and the restrictive use of antibiotics in The Netherlands.

Rapid diagnostic testing of methicillin-resistant Staphylococcus aureus carriage at different anatomical sites: costs and benefits of less extensive screening regimens.

Multiple body site screening and pre-emptive isolation of patients at risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage are considered essential for control of nosocomial spread. The relative importance of extranasal screening when using rapid diagnostic testing (RDT) is unknown. Using data from a multicentre study evaluating BD GeneOhm™ MRSA PCR (IDI), Xpert MRSA (GeneXpert) and chromogenic agar, added to conventional cultures, we determined cost-effectiveness assuming isolation measures would have been based on RDT results of different hypothetical screening regimes. Costs per isolation day avoided were calculated for regimes with single or less extensive multiple site RDT, regimes without conventional back-up cultures and when PCR would have been performed with pooling of swabs. Among 1764 patients at risk, MRSA prevalence was 3.3% (n = 59). In all scenarios the negative predictive value is above 98.4%. With back-up cultures of all sites as a reference, the costs per isolation day avoided were €15.19, €30.83 and €45.37 with 'nares only' screening using chromogenic agar, IDI and GeneXpert, respectively, as compared with €19.95, €95.77 and €125.43 per isolation day avoided when all body sites had been screened. Without back-up cultures costs per isolation day avoided using chromogenic agar would range from €9.24 to €76.18 when costs per false-negative RDT range from €5000 up to €50 000; costs for molecular screening methods would be higher in all scenarios evaluated. In conclusion, in a low endemic setting chromogenic agar screening added to multiple site conventional cultures is the most cost-effective MRSA screening strategy.

Highly resistant gram-negative microorganisms: incidence density and occurrence of nosocomial transmission (TRIANGLe Study).

OBJECTIVES: The objectives of this study were to determine the incidence density and the occurrence of horizontal spread of highly resistant gram-negative rods (HR-GNRs) in Dutch hospitals. The factors that influence these outcome measures were also investigated. METHODS: All patients with HR-GNRs, as determined by sample testing, who were hospitalized in 1 of 18 hospitals during a 6-month period (April through October 2007) were included in this study. For all available isolates, the species was identified, susceptibility was determined (including the presence of extended-spectrum ß-lactamases [ESBLs]), and molecular typing was performed. On the basis of a combination of species identification, molecular typing, and epidemiological data, the occurrence of nosocomial transmission was determined. RESULTS: The mean incidence density of patients with HR-GNRs was 55 per 100,000 patient-days (cumulative incidence, 39 per 10,000 patients admitted). A facility being a university hospital was a statistically significant (P = .03) independent determinant of a higher incidence of patients with HR-GNRs. The majority of HR-GNR isolates were ESBL producers. The adjusted transmission index-the ratio between secondary and primary cases-in the participating hospitals ranged from 0.0 to 0.2. The overall adjusted transmission index of HR-GNRs was 0.07. No determinants for a higher transmission index were identified. DISCUSSION: The nosocomial transmission rate of HR-GNRs was relatively low in all hospitals where well-established transmission-based precautions were used. The incidence density of patients with HR-GNRs was higher in university hospitals, probably due to the patient population and the complexity of the care provided.

Transmissibility of livestock-associated methicillin-resistant Staphylococcus aureus (ST398) in Dutch hospitals.

We quantified nosocomial transmission rates of sequence type (ST) 398 methicillin-resistant Staphylococcus aureus (MRSA) (an emerging livestock-associated MRSA clone) and non-ST398 MRSA isolates in patients hospitalized without infection control measures in 51 Dutch hospitals. Identification of 174 index patients initiated 139 post-exposure screenings of 9925 persons. There were 65 genotype-confirmed secondary cases (three and 62 for ST398 and non-ST398 MRSA, respectively), yielding a relative transmission risk for ST398 MRSA of 0.28 (95% CI 0.09-0.90), which was not sensitive to adjustment for duration of hospitalization at time of detection. Nosocomial transmission of ST398 MRSA is 72% less likely than that of non-ST398 MRSA strains.

Rapid screening of methicillin-resistant Staphylococcus aureus using PCR and chromogenic agar: a prospective study to evaluate costs and effects.

Pre-emptive isolation of suspected methicillin-resistant Staphylococcus aureus (MRSA) carriers is considered essential for controlling the spread of MRSA, but noncolonized patients will be isolated unnecessarily as a result of a delay in diagnosis of 3-5 days with conventional cultures. We determined costs per isolation day avoided, and incremental costs of rapid MRSA screening tests when added to conventional screening, but with decisions on isolation measures based on PCR results. A prospective multicentre study evaluating BD GeneOhm MRSA PCR (`IDI') (BD Diagnostics, San Diego, CA, USA), Xpert MRSA (`GeneXpert') (Cepheid, Sunnyvale, CA, USA) and chromogenic agar (MRSA-ID) (bioMérieux, Marcy-l'Etoile, France) was performed in 14 Dutch hospitals. Among 1764 patients at risk, MRSA prevalence was 3.3% (n=59). Duration of isolation was 19.7 and 16.1 h with IDI and GeneXpert, respectively, and would have been 30.0 and 76.2 h when based on chromogenic agar and conventional cultures, respectively. Negative predictive values (at a patient level) were 99.5%, 99.1% and 99.5% for IDI, GeneXpert and chromogenic agar, respectively. Numbers of isolation days were reduced by 60% and 47% with PCR-based and chromogenic agar-based screening, respectively. The cost per test was €56.22 for IDI, €69.62 for GeneXpert and €2.08 for chromogenic agar, and additional costs per extra isolation day were €26.34. Costs per isolation day avoided were €95.77 (IDI) and €125.43 (GeneXpert). PCR-based decision-making added €153.64 (IDI) and €193.84 (GeneXpert) per patient to overall costs and chromogenic testing would have saved €30.79 per patient. Rapid diagnostic testing safely reduces the number of unnecessary isolation days, but only chromogenic screening, and not PCR-based screening, can be considered as cost saving.

Methicillin-resistant Staphylococcus aureus in horses and horse personnel: an investigation of several outbreaks.

At the Veterinary Microbiological Diagnostic Center, the Netherlands, the percentage of methicillin-resistant Staphylococcus aureus (MRSA) isolates found in equine clinical samples increased from 0% in 2002 to 37% in 2008. MRSA of spa-type t064, belonging to MLST ST8 and spa-types t011 and t2123, both belonging to the livestock-associated MLST ST398, predominated. During an outbreak of post-surgical MRSA infections in horses at a veterinary teaching hospital in 2006/2007, MRSA isolates of spa-type t2123 were cultured from 7 horses and 4/61 personnel which indicated zoonotic transmission. After intervention the outbreak stopped. However, another outbreak occurred in 2008, where 17 equine MRSA isolates of spa-type t011 (n=12), t2123 (n=4), and t064 (n=1) were found. This time, 16/170 personnel were positive for MRSA with spa-type t011 (n=11) and t2123 (n=5). Personnel in close contact with horses were more often MRSA-positive (15/106) than those without (1/64). Screening of horses upon admission showed that 9.3% were MRSA-positive predominantly with spa-type t011. Weekly cross-sectional sampling of all hospitalized horses for 5 weeks showed that 42% of the horses were MRSA-positive at least once, again predominantly with spa-type t011, which suggests that nosocomial transmission took place. Fifty-three percent of the environmental samples were MRSA-positive, including samples from students' and staff members' rooms, and all were spa-type t011. This indicates that humans contribute to spreading the organism. Culturing of samples employing high-salt pre-enrichment performed better than a comparable method without pre-enrichment. Our results show that nosocomial transmission occurs in equine clinics and suggests that personnel play a role in the transmission.

[Optimisation of the antibiotic policy in the Netherlands. XII. The SWAB guideline for antimicrobial eradication of MRSA in carriers]. / Optimaliseren van het antibioticabeleid in Nederland. XII. SWAB-richtlijn voor de behandeling van MRSA-dragerschap.

The 'Stichting Werkgroep Antibioticabeleid' (SWAB; Dutch Working Party on Antibiotics Policy) has developed evidence-based guidelines for the antimicrobial treatment of methicillin-resistant Staphylococcus aureus (MRSA) carriers for the eradication of MRSA. A distinction was made between uncomplicated and complicated carriage depending on the presence or absence of an active MRSA infection, skin lesions, foreign body material, mupirocin resistance and/or extranasal carriage. The indication for treatment is determined by the consequences of carriage for the carrier and his/her environment, the adverse events of treatment, and the likelihood of a successful treatment. The first choice of treatment in uncomplicated carriers is a combination of mupirocin nasal ointment and disinfectant soap for 5 days, along with hygiene advice. If treatment fails, sources in the vicinity of the patient must be sought. Complicated carriers receive a combination of 2 oral antibiotics, in addition to mupirocin nasal ointment and disinfectant soap, for at least 7 days.

[Methicillin-resistant Staphylococcus aureus of livestock origin in Dutch hospitals: high-risk patients need only to be investigated if admitted to hospital]. / Meticillineresistente Staphylococcus aureus afkomstig uit de veestapel in Nederlandse ziekenhuizen: risicopatiënten alleen controleren bij eventuele ziekenhuisopname.

OBJECTIVE: To determine the incidence and prevalence of carriage of methicillin-resistent Staphylococcus aureus (MRSA) in patients and hospital personnel, and to examine the consequences of the revised Dutch MRSA guideline with respect to patients who have frequent contact with pigs or calves (in the course of their work). DESIGN: Retrospective and prospective observational study using questionnaires. METHOD: Since July 2006 patients who have contact with living pigs or calves have been regarded as a high-risk group for MRSA carriage, after it was established that this occupational group had an increased chance of carriage of the so-called non-typable MRSA (NT-MRSA). An inventory was made of incidence and prevalence of MRSA carriage in patients and hospital personnel, and of the consequences of the new MRSA policy, for the period July-December 2006. RESULTS: Information was obtained from 58 Dutch hospitals. On January 1 2007, 37 (64%) hospitals had changed their MRSA policy; 22% of the hospitals it was applied in accordance with the MRSA guideline. The new guideline resulted in an increase of MRSA screenings by 15% and of detected MRSA carriers by 44%. 73% of all MRSA screenings took place in the out-patients department. In regions with high pig-density the incidence of NT-MRSA was 12% in patients with risk factors for carriage. In 49% of the hospitals one or more NT-MRSA carriers were detected (range 1-19 carriers). Possible transmission of NT-MRSA in hospital was shown in 3 of 1,007 (0.3%) hospital personnel, but in none of the 183 fellow-patients, examined. In the same period transmission of typable MRSA was demonstrated in 41 of 2,019 (2.0%) patients and 33 of 5,190 (0.6%) of hospital personnel examined. Prevalence of NT-MRSA carriage in 6,197 screened hospital personnel was 0.05% (n = 3). CONCLUSION: The revised Dutch MRSA guideline lead to an increase in the number of MRSA screenings by 15%, particularly in the out-patients department, and to an increase in the number of detected MRSA carriers by 44%. During 306 months of observation no patient-to-patient transmission ofNT-MRSA was demonstrated.

Hospital infection control in the Netherlands.

In this paper, the organization of infection control in Dutch hospitals will be described generally. Local organization of infection control departments can of course differ due to special needs, special expertise or interests of the members of a department.

Ecological replacement of Enterococcus faecalis by multiresistant clonal complex 17 Enterococcus faecium.

The proportion of enterococcal infections caused by ampicillin-resistant Enterococcus faecium (AREfm) in a European hospital increased from 2% in 1994 to 32% in 2005, with prevalence rates of AREfm endemicity of up to 35% in at least six hospital wards. Diabetes mellitus, three or more admissions in the preceding year, and use of beta-lactams and fluoroquinolones, were all associated with AREfm colonisation. Of 217 AREfm isolates that were genotyped, 97% belonged to clonal complex 17 (CC17). This ecological change mimics events preceding the emergence of vancomycin-resistant E. faecium (VREF) in the USA and may presage the emergence of CC17 VREF in European hospitals.

Prevalence of hospital-acquired infections during successive surveillance surveys conducted at a university hospital in the Netherlands.

OBJECTIVE: To monitor hospital-wide trends in the prevalence of hospital-acquired infections (HAIs) in order to identify areas where the risk of infection is increasing. METHODS: Successive surveillance surveys were conducted twice yearly, from November 2001 until May 2004, to determine the prevalence of HAIs at 2 Dutch hospitals, using Centers for Disease Control and Prevention criteria. RESULTS: In all, 340 HAIs were observed in 295 (11.1%) of 2,661 patients surveyed. The overall prevalence per survey varied from 10.2% to 15.6%, with no significant differences between successive surveys. In the surgical department, the prevalence of HAIs increased from 10.8 cases per 100 surgeries in November 2001 to 20.4 cases per 100 surgeries in May 2002. Further analysis revealed a high prevalence of surgical site infection among patients who had an orthopedic procedure performed. In the neurology-neurosurgery department, the prevalence increased from 13.0 cases per 100 patients in May 2002 to 26.6 cases per 100 patients in May 2003 and involved several types of infection. Further analysis retrieved exceptionally high incidences of infections associated with cerebrospinal fluid drainage. Specific infection control interventions were developed and implemented in both departments. The total cost of the surveys was estimated to be euro9,100 per year. CONCLUSION: Successive performance of surveillance surveys is a simple and cheap method to monitor the prevalence of infection throughout the hospital and appeared instrumental in identifying 2 departments with increased infection rates.

[Endocarditis due to meticillin-resistant Staphylococcus aureus originating from pigs]. / Endocarditis door meticillineresistente Staphylococcus aureus afkomstig van varkens.

A 63-year-old woman with a kidney transplant was admitted with endocarditis caused by meticillin-resistant Staphylococcus aureus (MRSA). Once her antibiotic therapy had been adjusted to the sensitivity-pattern of the bacterial strain she recovered, without the need for surgical intervention. The isolated S. aureus was typed by multi-locus sequence typing as sequence type 398, a MRSA-strain that has recently been isolated from a high percentage of Dutch pigs. This is the first report of a life-threatening infection with this pig MRSA. This strain is genetically different from the globally dispersed nosocomial MRSA-strains, and also from the strains that have been epidemic for several years in the USA as the causative agent ofcommunity-acquired skin infections. The Dutch Working Group on Infection Prevention (WIP) has recently adjusted its guidelines to halt further spread of this strain, and advises that the population at risk (pig breeders, slaughterhouse personnel and veterinarians) be held in isolation when hospitalised until MRSA colonisation has been excluded. The patient described here, however, did not belong to this population at risk.

[The Dutch MRSA policy should be retained]. / Het Nederlandse MRSA-beleid is succesvol.

The Dutch methicillin-resistant Staphylococcus aureus (MRSA) 'search and destroy' policy is effective. MRSA should be banned from hospitals: MRSA infections are associated with increased mortality and costs. In addition, widespread use of vancomycin for treating MRSA infections encourages the spread and development of vancomycin-resistant micro-organisms.

Trends in fungaemia and antifungal susceptibility in the Netherlands.

We retrospectively evaluated fungaemia over the period 1996 to 2001 in five university hospitals. Over 350,000 blood cultures were collected during more than 7 million days of hospitalisation. The average rate of fungaemia over the six-year period was 0.82 per 10,000 patient days (range 0.65 to 1.21 per 10,000 patient days). The proportion of bloodstream infections caused by Candida albicans remained stable throughout the study period with a mean of 53% (range 48 to 62%). This is a change from trends described in previous studies, including a survey performed in the Netherlands. This study shows a new, stable rate of fungaemia and no further signs of increasing rate of infections due to non-albicans Candida species. Susceptibility to all tested antifungal agents remained stable throughout the study period.

Genotyping and preemptive isolation to control an outbreak of vancomycin-resistant Enterococcus faecium.

BACKGROUND: Control of vancomycin-resistant Enterococcus faecium (VRE) in European hospitals is hampered because of widespread asymptomatic carriage of VRE by healthy Europeans. In 2000, our hospital (The University Medical Center Utrecht, Utrecht, The Netherlands) was confronted with a large outbreak of VRE. INTERVENTION: On the basis of genotyping (by pulsed-field gel electrophoresis), epidemic and nonepidemic VRE strains were distinguished, and infection-control measures were exclusively targeted toward epidemic VRE. The outbreak was retrospectively divided into 3 periods of different infection-control measures. Compliance with use of alcohol-based hand rubs was enforced during all periods. Period I involved active surveillance, isolation of carriers, and cohorting (duration, 4 months); preemptive isolation of high-risk patients for VRE colonization was added in period II (7 months); and cohorting and preemptive isolation were abandoned in period III (18 months). METHODS: When the outbreak was identified, 27 patients in 6 wards were colonized; 93% were colonized with an epidemic VRE strain. Detection rates of nonepidemic VRE were 3.5%, 3.0%, and 2.9% among 683, 810, and 977 screened patients in periods I, II, and III, respectively, comparable to a prevalence of 2% (95% confidence interval [CI], 1%-3.5%) among 600 nonhospitalized persons. The relative risks of detecting epidemic VRE in periods II and III, compared with period I, were 0.67 (95% CI, 0.41-1.10) for period II and 0.02 (95% CI, 0.002-0.6) for period III. Infection-control measures were withheld for patients colonized with nonepidemic VRE (76 [54%] of 140 patients with a test result positive for VRE). Use of alcohol-based hand rubs increased by 31%-275% in outbreak wards. CONCLUSION: Genotyping-targeted infection control, isolation of VRE carriers, enhancement of hand-hygiene compliance, and preemptive isolation successfully controlled nosocomial spread of epidemic VRE infection.