A search strategy for detecting duodenoscope-associated infections: a retrospective observational study.

BACKGROUND: Duodenoscope-associated infections (DAIs) are exogenous infections resulting from the use of contaminated duodenoscopes. Though numerous outbreaks of DAI have involved multidrug-resistant micro-organisms (MDROs), outbreaks involving non-MDROs are also likely to occur. Detection challenges arise as these infections often resolve before culture or because causative strains are not retained for comparison with duodenoscope strains. AIM: To identify and analyse DAIs spanning a seven-year period in a tertiary care medical centre. METHODS: This was a retrospective observational study. Duodenoscope cultures positive for gastrointestinal flora between March 2015 and September 2022 were paired with duodenoscope usage data to identify patients exposed to contaminated duodenoscopes. Analysis encompassed patients treated after a positive duodenoscope culture and those treated within the interval from a negative to a positive culture. Patient identification numbers were cross-referenced with a clinical culture database to identify patients developing infections with matching micro-organisms within one year of their procedure. A 'pair' was established upon a species-level match between duodenoscope and patient cultures. Pairs were further analysed via antibiogram comparison, and by whole-genome sequencing (WGS) to determine genetic relatedness. FINDINGS: Sixty-eight pairs were identified; of these, 21 exhibited matching antibiograms which underwent WGS, uncovering two genetically closely related pairs categorized as DAIs. Infection onset occurred up to two months post procedure. Both causative agents were non-MDROs. CONCLUSION: This study provides crucial insights into DAIs caused by non-MDROs and it highlights the challenge of DAI recognition in daily practice. Importantly, the delayed manifestation of the described DAIs suggests a current underestimation of DAI risk.

Proposal for a screening protocol for Candida auris colonization.

BACKGROUND: Candida auris is an emerging multidrug-resistant yeast which can cause severe infection in hospitalized patients. Since its first detection in 2009, C. auris has spread globally. The control and elimination of this pathogen in a hospital setting is particularly challenging because of its ability to form biofilms, allowing for long-term patient colonization and persistence in the environment. Identification of C. auris from cultures is difficult due to the morphologic similarities to other yeasts, its slow growth, and the low culture sensitivity when using standard agars and temperatures. AIM: We have developed a screening protocol for C. auris colonization using an in-house-developed polymerase chain reaction (PCR), combined with confirmatory culture in optimized conditions. METHODS: C. auris-specific primers and probe were developed, targeting the internal transcribed spacer (ITS) region, and specificity was confirmed in silico using the BLAST tool. The PCR was validated using a panel of 12 C. auris isolates and 103 isolates from 22 other Candida species and was shown to be 100% accurate. The limit of detection of the assay was determined at approximately four cells per PCR. FINDINGS: C. auris screening was introduced on February 15th, 2023, and was used for patients who had been admitted to a healthcare facility abroad in the two months prior to admission to our hospital. The screening protocol included swabs from nose, throat, rectum, axilla, and groin. In the first eight months, 199 patients were screened and seven were found positive (4%). CONCLUSION: Our proposed screening protocol may contribute to control C. auris in hospitals.

Association of environmental surface contamination with hand hygiene and infections in nursing homes: a prospective cohort study.

BACKGROUND: Little is known about the presence of infections in nursing home residents, the causative micro-organisms, how hand hygiene (HH) influences the presence of infections in residents, and the extent to which environmental contamination is associated with the incidence of infection among residents. AIMS: To establish if environmental contamination can be used as an indicator for HH compliance, and if environmental contamination is associated with the incidence of infection. METHODS: Environmental surface samples (ESS) were collected in an exploratory study as part of a HH intervention in 60 nursing homes. ESS results from three distinct surfaces (nurses' station, communal toilet and residents' shared living area) were compared with nurses' HH compliance and the incidence of infection among residents. Real-time polymerase chain reaction assays were used to detect norovirus genogroup I and II, rhinovirus and Escherichia coli. HH compliance was measured by direct observation. The incidence of infection was registered weekly. FINDINGS: Rhinovirus (nurses' station: 41%; toilet: 14%; living area: 29%), norovirus (nurses' station: 18%; toilet: 12%; living area: 16%) and E. coli (nurses' station: 14%; toilet: 58%; living area: 54%) were detected. No significant (P<0.05) associations were found between HH compliance and the presence of micro-organisms. An association was found between E. coli contamination and the incidence of disease in general (P=0.04). No other associations were found between micro-organisms and the incidence of disease. CONCLUSION: Rhinovirus, norovirus and E. coli were detected on surfaces in nursing homes. No convincing associations were found between environmental contamination and HH compliance or the incidence of disease. This study provides reference data about surface contamination.

Prevalence of and risk factors for extended-spectrum beta-lactamase genes carriership in a population-based cohort of middle-aged and elderly.

INTRODUCTION: Increasing resistance to beta-lactam antibiotics is an alarming development worldwide. Fecal carriership of TEM, SHV, CTX-M and CMY was studied in a community-dwelling population of middle-aged and elderly individuals. PATIENTS AND METHODS: Feces was obtained from individuals of the Rotterdam Study. Carriership of the TEM, SHV, CTX-M and CMY genes was determined using real-time polymerase chain reaction (qPCR). Possible associations were investigated between carriership of these genes and several risk factors, such as the use of antimicrobial drugs, diabetes mellitus, protein pump inhibitor (PPI) use, travelling, the composition of the gut microbiota, and intake of certain foods. RESULTS: The most prevalent gene was TEM (53.0%), followed by SHV (18.4%), CTX-M (5.4%) and CMY (3.6%). Use of penicillins with extended spectrum was associated with TEM carriership, whereas use of macrolides and lincosamides was associated with TEM and SHV carriership. Interestingly, use of PPIs was associated with a higher prevalence of carriership of TEM, SHV and CMY (TEM: odds ratio [OR] 1.34; 95% confidence interval [CI] 1.05-1.77; SHV: OR 2.17; 95%CI 1.55-2.87; CMY: OR 2.26; 95%CI 1.23-4.11). Furthermore, associations were found between the richness and composition of the gut microbiota and TEM and SHV carriership. CONCLUSIONS: The prevalence of carriership of TEM was substantial, but the prevalence of carriership of the extended-spectrum ß-lactamase gene, CTX-M and the AmpC ß-lactamase gene, CMY was relatively low in this community-dwelling, population-based cohort. The composition of the microbiota might play a role in the retention of resistance genes, but future studies are necessary to further elucidate this relationship.

Diagnostic implications of mycetoma derived from Madurella pseudomycetomatis isolates from Mexico.

BACKGROUND: At the dermatology service of the General Hospital of Mexico City, Mexico, two patients, father and son, with black-grain mycetoma were seen. The grains were isolated, and the cultured fungi were identified as Madurella mycetomatis based on morphology. Using the M. mycetomatis specific PCR, amplicons of a different size than that of the M. mycetomatis type strain were obtained. OBJECTIVE: To determine the causative agent of the two black-grain mycetoma cases and develop non-culture-based diagnostic tools to identify them to the species level. METHODS: The M. mycetomatis specific, the internal transcribed spacer (ITS) region, ß-tubulin (BT) and ribosomal binding protein 2 (RBP2) PCRs were used to confirm the identity of the isolates. Genetic variation was established by amplification fragment length polymorphisms. To determine the antifungal susceptibility profile, the Sensititre™ YeastOne™ assay was used. To develop a species-specific PCR primers were designed on the sequenced PCR amplicon from the M. mycetomatis specific PCR. RESULTS: By analyzing the ITS, BT and RBP2 regions the isolates were identified as Madurella pseudomycetomatis. The isolates from father and son were similar but not identical to M. pseudomycetomatis from Venezuela and one from an unknown origin. Madurella pseudomycetomatis isolates were inhibited by itraconazole, posaconazole and voriconazole but showed increased MIC values for amphotericin B and fluconazole. They were not inhibited by the echinocandins and five flucytosine. The two patients were treated with itraconazole resulting in cure for the father while the son was lost to follow-up. The species-specific PCR developed for M. pseudomyceotmatis was discriminative and specific. CONCLUSION: Madurella pseudomycetomatis is genetically diverse with same susceptibility profile as M. mycetomatis and causes eumycetoma in Latin America. The M. pseudomycetomatis specific PCR can be used to identify this causative agent to the species level; however, this needs to be validated in an endemic setting.

Unexpected mechanisms of resistance in Dutch Pseudomonas aeruginosa isolates collected during 14 years of surveillance.

Pseudomonas aeruginosa is one of the most important causes of infection in intensive care units (ICUs). It is intrinsically resistant to many antimicrobials and easily acquires additional resistance genes via horizontal gene transfer of mobile genetic elements. In this study, 1528 P. aeruginosa isolates obtained from a Dutch national surveillance programme between the years 1998-2011 were analysed for the presence of extended-spectrum ß-lactamase (ESBL) genes (blaCTX-M, blaSHV, blaTEM, blaBEL, blaPER, blaVEB and blaOXA-10) and metallo-ß-lactamase (MBL) genes (blaIMP, blaVIM and blaNDM). Of the ceftazidime-resistant isolates, 6.2% tested phenotypically positive for ESBL. Moreover, a Verona integron-encoded MBL (VIM) gene was found in 3.1% of isolates that were phenotypically resistant to imipenem and/or meropenem. Multilocus sequence typing (MLST) of ESBL-positive isolates indicated ST1216, ST111 and ST622, with all blaVIM-positive isolates belonging to the ST111 clone. Although the prevalence of ESBL and MBL phenotypes in this Dutch national surveillance collection of >1500 ICU P. aeruginosa isolates was very low, all VIM-producing isolates belonged to the high risk-associated, international, clonal complex CC111, and most ESBL-producing isolates belonged to clonal complexes known for their successful spread, e.g. CC111 and CC235. These data indicate that high-risk clones of P. aeruginosa were present in the Netherlands between 1998-2011 and probably spread unnoticed throughout Dutch hospitals.

Detection of azole-susceptible and azole-resistant Aspergillus coinfection by cyp51A PCR amplicon melting curve analysis.

BACKGROUND: The AsperGenius® assay is a multiplex real-time PCR test that allows the simultaneous detection of Aspergillus species and identification of the most common mutations in the Aspergillus fumigatus cyp51A gene conferring resistance (TR34/L98H and TR46/T289A/Y121F) by using melting curve analysis. Mixed infections with azole-resistant and susceptible A. fumigatus have rarely been described. METHODS: The AsperGenius® multiplex real-time PCR assay (PathoNostics, Maastricht, the Netherlands) was used on bronchoalveolar lavage (BAL) samples of 91 consecutive patients with a suspected invasive Aspergillus infection at the Erasmus MC University Medical Center, Rotterdam. RESULTS: In three cases the AsperGenius® assay indicated the simultaneous presence of WT and mutant genes (two patients with TR34/L98H mutation and one patient with TR46/T289A/Y121F mutation) and therefore mixed infections with azole-susceptible and -resistant isolates. In one of the three cases, the mixed infection was confirmed by phenotypic antifungal testing of multiple A. fumigatus colonies. CONCLUSIONS: The use of a dedicated A. fumigatus cyp51A resistance PCR allowed the detection of mixed infections with azole-resistant and -susceptible Aspergillus strains. These mixed infections may remain undiagnosed with conventional phenotypic susceptibility testing.

Identification and nomenclature of the genus Penicillium.

Penicillium is a diverse genus occurring worldwide and its species play important roles as decomposers of organic materials and cause destructive rots in the food industry where they produce a wide range of mycotoxins. Other species are considered enzyme factories or are common indoor air allergens. Although DNA sequences are essential for robust identification of Penicillium species, there is currently no comprehensive, verified reference database for the genus. To coincide with the move to one fungus one name in the International Code of Nomenclature for algae, fungi and plants, the generic concept of Penicillium was re-defined to accommodate species from other genera, such as Chromocleista, Eladia, Eupenicillium, Torulomyces and Thysanophora, which together comprise a large monophyletic clade. As a result of this, and the many new species described in recent years, it was necessary to update the list of accepted species in Penicillium. The genus currently contains 354 accepted species, including new combinations for Aspergillus crystallinus, A. malodoratus and A. paradoxus, which belong to Penicillium section Paradoxa. To add to the taxonomic value of the list, we also provide information on each accepted species MycoBank number, living ex-type strains and provide GenBank accession numbers to ITS, ß-tubulin, calmodulin and RPB2 sequences, thereby supplying a verified set of sequences for each species of the genus. In addition to the nomenclatural list, we recommend a standard working method for species descriptions and identifications to be adopted by laboratories working on this genus.

Phylogeny, identification and nomenclature of the genus Aspergillus.

Aspergillus comprises a diverse group of species based on morphological, physiological and phylogenetic characters, which significantly impact biotechnology, food production, indoor environments and human health. Aspergillus was traditionally associated with nine teleomorph genera, but phylogenetic data suggest that together with genera such as Polypaecilum, Phialosimplex, Dichotomomyces and Cristaspora, Aspergillus forms a monophyletic clade closely related to Penicillium. Changes in the International Code of Nomenclature for algae, fungi and plants resulted in the move to one name per species, meaning that a decision had to be made whether to keep Aspergillus as one big genus or to split it into several smaller genera. The International Commission of Penicillium and Aspergillus decided to keep Aspergillus instead of using smaller genera. In this paper, we present the arguments for this decision. We introduce new combinations for accepted species presently lacking an Aspergillus name and provide an updated accepted species list for the genus, now containing 339 species. To add to the scientific value of the list, we include information about living ex-type culture collection numbers and GenBank accession numbers for available representative ITS, calmodulin, ß-tubulin and RPB2 sequences. In addition, we recommend a standard working technique for Aspergillus and propose calmodulin as a secondary identification marker.

Different colonization patterns of Aspergillus terreus in patients with cystic fibrosis.

Aspergillus terreus is a common soil saprophyte. After Aspergillus fumigatus and Scedosporium apiospermum it ranks third amongst the filamentous fungi colonizing the airways of patients with cystic fibrosis. In this context, the clinical presentation of A. terreus infection mainly corresponds to allergic broncho-pulmonary aspergillosis. In the work presented here, we studied colonization patterns of A. terreus in CF patients by genotyping using nine short tandem repeat markers. A total of 115 clinical isolates from respiratory secretions collected from five French CF patients were studied. The number of isolates varied from 15 to 39 per patient, and the duration of the follow-up period ranged from 2 months to 7.5 years. Seventeen genotypes were identified, corresponding to three distinct colonization patterns. The first colonization pattern consisted of a chronic colonization by one dominant genotype associated with few other genotypes found only incidentally. The second colonization pattern consisted of a prolonged colonization by two distinct genotypes detected simultaneously. The last pattern was characterized by multiple different genotypes that were present only transiently. These results demonstrate the importance of genotyping clinical isolates before making conclusions about chronic colonization of the airways in CF patients in the case of repeated isolation of the fungus.

Outbreak of invasive aspergillosis after major heart surgery caused by spores in the air of the intensive care unit.

BACKGROUND: Outbreaks of invasive aspergillosis (IA) are believed to be caused by airborne Aspergillus conidia. Few studies have established a correlation between high levels of Aspergillus fumigatus conidia and the appearance of new cases of IA or have demonstrated matching genotypes between clinical isolates and those from the environment. METHODS: We detected an outbreak of IA (December 2006 through April 2008) in the major heart surgery intensive care unit (MHS-ICU) of our institution. Our local surveillance program consists of monthly environmental air sampling in operating rooms and ICUs for quantitative and qualitative identification of filamentous fungi. During the study period, we obtained 508 environmental samples from 3 different periods: 6 months before the outbreak, during it, and 6 months after it. Available environmental and clinical strains were genotyped according to the short tandem repeats assay. RESULTS: Seven patients developed proven or probable IA (5 with lung infection, 1 with mediastinitis, and 1 with lung infection and mediastinitis). A. fumigatus was involved in 6 cases. The underlying conditions of the patients were heart transplantation (n = 3), corticosteroid-dependent conditions (n = 2), and diabetes mellitus (n = 2). The mortality rate was 85.7%. Before and after the outbreak (±6 months), the median airborne A. fumigatus conidia levels were 0 colony-forming units (CFUs) per cubic meter, and no cases of IA occurred during these periods. However, during the outbreak period, the occurrence of the 6 cases of IA caused by A. fumigatus was linked to peaks of abnormally high A. fumigatus airborne conidia levels (175, 50, 25, 20, 160, and 400 CFUs/m(3)) in the MHS-ICU, whereas counts in the air of both operating rooms remained negative. Matches between A. fumigatus genotypes collected from the air of the MHS-ICU and from representative clinical samples were found in 3 of the 6 patients. The outbreak abated when high-efficiency particulate air filters were installed in the affected areas. CONCLUSIONS: Our study revealed that abnormally high levels of airborne A. fumigatus conidia correlated with new cases of IA, even in patients who were not severely immunocompromised. The demonstration of matches between air and clinical genotypes reinforces the role of environmental air in the acquisition of IA during the period following MHS. Environmental monitoring of Aspergillus spores in the air of postoperative units is mandatory, even when these units receive nonimmunocompromised patients undergoing major surgery.

The Q fever epidemic in The Netherlands: history, onset, response and reflection.

The 2007-2009 human Q fever epidemic in The Netherlands attracted attention due to its magnitude and duration. The current epidemic and the historical background of Q fever in The Netherlands are reviewed according to national and international publications. Seroprevalence studies suggest that Q fever was endemic in The Netherlands several decades before the disease was diagnosed in dairy goats and dairy sheep. This was in 2005 and the increase in humans started in 2007. Q fever abortions were registered on 30 dairy goat and dairy sheep farms between 2005 and 2009. A total of 3523 human cases were notified between 2007 and 2009. Proximity to aborting small ruminants and high numbers of susceptible humans are probably the main causes of the human Q fever outbreak in The Netherlands. In general good monitoring and surveillance systems are necessary to assess the real magnitude of Q fever.

Prevalence and molecular mechanism of macrolide resistance in beta-haemolytic streptococci in The Netherlands.

The prevalence of resistance to erythromycin and clindamycin as well as the presence of the resistance genes mef(A), mef(E), erm(A) and erm(B) were determined in 1076 consecutive isolates of beta-haemolytic streptococci of Lancefield groups A (n=219), B (n=562),C (n=58) and G (n=237) collected during 2005 and 2006. The prevalence of macrolide resistance was highest in group C streptococci (6.9%), followed by group B (5.3%), group G (4.6%) and group A (1.4%). Eighty-eight percent of resistance was mediated by erm(A) and erm(B) genes. Macrolide resistance in beta-haemolytic streptococci in The Netherlands is low, but increasing macrolide resistance was observed in group B streptococci.

Application of multiple-locus variable-number tandem-repeat analysis to determine clonal spread of toxin A-negative Clostridium difficile in a general hospital in Buenos Aires, Argentina.

Isolates from patients with Clostridium difficile infection (CDI) usually produce both toxin A (TcdA) and toxin B (TcdB), but an increasing number of reports from Europe and Asia mention infections with TcdA-negative, TcdB-positive (A-/B+) strains, usually characterized as PCR ribotype 017 (type 017). Incidence rates of CDI per 10 000 admissions in a 200-bed Argentinean general hospital were 37, 84, 67, 43, 48 and 42 for the years 2000 to 2005, respectively. The annual percentages of type 017 CDI were 7.7%, 64.6%, 91.4%, 92.0%, 75.0% and 86.4%, respectively. Comparison of 112 017-CDI patients with 41 non-017-CDI patients revealed that 017-CDI patients were more often male (68.8% vs. 46.3%; odds ratio 2.55, 95% confidence interval 1.23-5.50). All type 017 strains tested belonged to toxinotype VIII and had a 1.8-kb deletion in tcdA. In addition, 90% of tested type 017 isolates had high-level resistance to clindamycin and erythromycin, determined by the presence of the ermB gene. Multiple-locus variable-number tandem-repeat analysis (MLVA) was applied to 56 Argentinean isolates and 15 isolates from seven other countries. Country-specific clonal complexes were found in each country. Among 56 Argentinean isolates, four clonal complexes were recognized, accounting for 61% of all isolates. These clonal complexes did not show correlation over time, but seemed to be restricted to specific wards, mainly internal medicine and pulmonology wards. A total of 56% of recurrent infections were caused by a different isolate, despite identification of an identical PCR-ribotype. We conclude that C. difficile type 017 gradually replaced other circulating PCR ribotypes and that MLVA provides detailed insight into nosocomial spread.

MLST versus microsatellites for typing Aspergillus fumigatus isolates.

In recent years, there has been a clear and growing tendency to use exact typing methods for discrimination between microbial isolates. Exact typing methods that yield an unambiguous typing result offer a number of advantages over conventional methods in the generation of typing data that is reproducible, portable and exchangeable. Two such methods are multi-locus sequence typing (MLST) and microsatellite-based typing. Here I will discuss the basic principles of both methods and compare them from a practical and performance point of view with respect to typing Aspergillus fumigatus isolates. Microsatellites offer the best available typing option by outperforming MLST in terms of speed, throughput, costs and discriminatory power. This latter advantage of microsatellites is a direct consequence of their inherent instability. This (in)stability of individual microsatellite markers and alleles should be taken into account in the interpretation of microsatellite-based typing data.

Interlaboratory reproducibility of a single-locus sequence-based method for strain typing of Aspergillus fumigatus.

Seven international laboratories tested the recently proposed single-locus typing strategy for Aspergillus fumigatus subtyping for interlaboratory reproducibility. Comparative sequence analyses of portions of the locus AFUA_3G08990, encoding a putative cell surface protein (denoted CSP), was performed with a panel of Aspergillus isolates. Each laboratory followed very different protocols for extraction of DNA, PCR, and sequencing. Results revealed that the CSP typing method was a reproducible and portable strain typing method.

Interlaboratory reproducibility of a microsatellite-based typing assay for Aspergillus fumigatus through the use of allelic ladders: proof of concept.

An interlaboratory study was performed with the aim of investigating the reproducibility of a multiplex microbial microsatellite-based typing assay for Aspergillus fumigatus in different settings using a variety of experimental and analytical conditions and with teams having variable prior microsatellite typing experience. In order to circumvent problems with exchange of sizing data, allelic ladders are introduced as a straightforward and universally applicable concept for standardization of such typing assays. Allelic ladders consist of mixtures of well-characterized reference fragments to act as reference points for the position in an electrophoretic trace of fragments with established repeat numbers. Five laboratories independently analysed six microsatellite markers in 18 samples that were provided either as DNA or as A. fumigatus conidia. Allelic data were reported as repeat numbers and as sizes in nucleotides. Without the use of allelic ladders, size differences of up to 6.7 nucleotides were observed, resulting in interpretation errors of up to two repeat units. Difficulties in interpretation were related to non-specific amplification products (which were resolved with explanation) and bleed-through of the different fluorescent labels. In contrast, after resolution of technical or interpretive problems, standardization of sizing data by using allelic ladders enabled all participants to produce identical typing data. The use of allelic ladders as a routine part of molecular typing using microsatellite markers provides robust results suitable for interlaboratory comparisons and for deposition in a global typing database.

[An outbreak of psittacosis at a bird-fanciers fair in the Netherlands]. / Een uitbraak van psittacose na een vogelbeurs.

Within 2 weeks after a bird-fanciers fair in the Netherlands in November 2007 11 patients presented at our hospital with fever, shivers and severe headache. Dyspnea and dry cough were less common, although the chest X-ray showed a consolidation in 9 out of 11 patients. The clinical diagnosis of psittacosis was quickly confirmed using real-time PCR, although the sensitivity of this test was low (20%). In 9 patients the diagnosis was later confirmed by a rise in complement fixing antibodies in paired sera. None of the patients needed intensive care treatment. All patients recovered uneventfully with antibiotic treatment. Psittacosis is an avian zoonosis, caused by Chlamydophila psittaci. Humans are infected by inhalation of the bacterium that is shedded by excreta or dust from feathers of different sites of either sick or asymptomatic, mostly psittacine, birds. The clinical picture ranges from asymptomatic or mild, flue-like symptoms to severe illness. A timely diagnosis is necessary for successful outbreak management. The realtime PCR is an adequate test in that respect.

Molecular typing of Aspergillus species.

Aspergillus species are widely distributed fungi that release large amounts of airborne conidia, which are dispersed in the environment. Several Aspergillus species have been described as human pathogens. Molecular techniques have been developed to investigate the epidemiological relation between environmental and clinical isolates. Several typing methods have been described for Aspergillus species, most of them with reference to Aspergillus fumigatus. Here, we summarise all the different available molecular typing techniques for Aspergillus. The performance of these techniques is evaluated with respect to their practical feasibility, and their interpretation and discriminatory power assessed. For A. fumigatus isolates, a large extent of genetic variability is demonstrated and therefore fingerprinting techniques with high discriminatory power and high reproducibility are required for this species. Afut1-restriction fragment length polymorphism and microsatellite typing showed the highest discriminatory power. In addition, the microsatellites show excellent reproducibility. Other typing techniques are still useful for smaller epidemiological problems and for less well-equipped laboratories.

Prevalence of methicillin-resistant Staphylococcus aureus among veterinarians: an international study.

Pig farmers and veterinarians in contact with livestock in The Netherlands have a higher risk of methicillin-resistant Staphylococcus aureus (MRSA) carriage than the general population. The objective of this study was to investigate whether this is also true for other professionals in contact with pigs in an international setting. A convenience sample of 272 participants at an international conference on pig health in Denmark was screened for MRSA carriage using combined nose/throat swabs and were asked to complete a questionnaire concerning animal contacts, exposure to known MRSA risk-factors, and the protective measures taken when entering pig farms. In total, 34 (12.5%) participants from nine countries carried MRSA. Thirty-one of these isolates were non-typeable by pulsed-field gel electrophoresis following SmaI digestion of chromosomal DNA. All of the non-typeable isolates belonged to spa types (t011, t034, t108, t571, t567 and t899) that correspond to multilocus sequence type 398. All of the above-mentioned spa types, with the exception of t899, have been isolated previously from either Dutch pigs, pig farmers and/or veterinarians. Protective measures, e.g., masks, gowns and gloves, did not protect against MRSA acquisition. Transmission of MRSA from pigs to staff tending to these animals appears to be an international problem, creating a new reservoir for community-acquired MRSA (CA-MRSA) in humans in Europe, and possibly worldwide. The rise of a new zoonotic source of MRSA could have a severe impact on the epidemiology of CA-MRSA, and may have consequences for the control of MRSA, especially in those countries that maintain a low prevalence by means of search-and-destroy policies.