69 research outputs found

    A longitudinal study on the persistence of Livestock Associated-MRSA in swine herds

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    In recent years, a new type of MRSA, now called livestock-associated MRSA (LA-MRSA), belonging to the clonal complex (CC) 398, has globally emerged in swine world wide. Aim of this study was to gain more insight into the persistence of LA-MRSA in different types of pig farms over a period of two years. To investigate this, 15 MRSA-positive herds from a previous study were selected; an additional pig farm was selected because this one was found to be positive with a human MRSA-strain. Starting in September 2009, five dust samples were collected every two months. Samples were analysed for MRSA and spa-typing was done to confirm that MRSA isolates belonged to CC398 and to gain insight into persistence of strains within a farm. Three herds were positive on all sampling occasions and were consistently contaminated with LA-MRSA. In the remaining herds, occasionally no positive dust samples were found at some sampling moments. The predominating spa -types were t011 and t108. A maximum of 5 different spa-types were found in two herds, with 3 different spa-types present in one sampling, indicating multiple introductions. These results show that LA-MRSA remains present on a pig farm over a long period. Most likely, transmission within the herd occurs after initial introduction, and an endemic situation seems to be the endpoint. The relatively low sensitivity of dust sampling compared to sampling of animals, the small sample size and lack of strict standardization of dust sampling might explain occasional negative samplings in overall positive herds. However, a true change of a positive MRSA-status to a negative status, followed by re-introduction cannot be ruled out in our study design

    Livestock-associated methicillin resistant Staphylococcus aureus in pigs - prevalence, risk factors and transmission dynamics

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    In 2004, an association between human carriage of methicillin resistant Staphylococcus aureus (MRSA) and contact with pigs was found. To assess the implications of this finding for veterinary and public health more insight into the prevalence, risk factors and transmission dynamics of this so-called livestock-associated (LA-)MRSA was needed. Therefore, field and experimental studies were conducted in pig and human populations of which the results are presented in this thesis. First, observational studies on pig farms were performed to estimate the prevalence of MRSA positive herds, and to identify factors associated with LA-MRSA in pig herds. It was shown that LA-MRSA was present in the majority, i.e. ~70%, of Dutch pig herds and that the prevalence increased over time. Larger herds were more often found LA-MRSA positive than smaller herds, and transmission was shown to occur by animal trade. From all this, it was concluded that LA-MRSA has become endemic in the Dutch pig population. Secondly, studies on LA-MRSA in pigs, the environment and personnel in pig slaughterhouses were performed. In pigs, a clear increase in LA-MRSA positive pigs from 0 to 60% was shown in the time period between loading at the farm and stunning at the slaughterhouse. This indicated a very rapid transmission of LA-MRSA between pigs through direct contact or through contact with a contaminated environment. An increase in LA-MRSA positive environmental samples taken in the slaughterhouse was found during the working day. In personnel, LA-MRSA prevalence was 6% and working with live pigs was the single most important factor for being positive; personnel not working with pigs or working only with dead pigs were all LA-MRSA negative. Thirdly, transmission of LA-MRSA within herds was studied longitudinally both in an experimental setting and also in 6 pig herds. Transmission rates and the factors affecting these rates were determined. The results of both studies indicated that LA-MRSA is able to spread easily and persist in pig populations, resulting in an endemic situation. Use of selective antimicrobials has a positive effect on the transmission rate of LA-MRSA, but transmission occurs even without use of antimicrobials. The key to limiting LA-MRSA transmission from pigs to humans is to eliminate the source, i.e. eradicate LA-MRSA from pig herds, and a combination of different intervention strategies controlling both within- and between-herd transmission will be needed to achieve this. </p

    Longitudinal study on transmission of MRSA CC398 within pig herds

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    Background Since the detection of MRSA CC398 in pigs in 2004, it has emerged in livestock worldwide. MRSA CC398 has been found in people in contact with livestock and thus has become a public health issue. Data from a large-scale longitudinal study in two Danish and four Dutch pig herds were used to quantify MRSA CC398 transmission rates within pig herds and to identify factors affecting transmission between pigs. Results Sows and their offspring were sampled at varying intervals during a production cycle. Overall MRSA prevalence of sows increased from 33% before farrowing to 77% before weaning. Overall MRSA prevalence of piglets was > 60% during the entire study period. The recurrent finding of MRSA in the majority of individuals indicates true colonization or might be the result of contamination. Transmission rates were estimated using a Susceptible-Infectious-Susceptible (SIS-)model, which resulted in values of the reproduction ratio (R0) varying from 0.24 to 8.08. Transmission rates were higher in pigs treated with tetracyclins and ß-lactams compared to untreated pigs implying a selective advantage of MRSA CC398 when these antimicrobials are used. Furthermore, transmission rates were higher in pre-weaning pigs compared to post-weaning pigs which might be explained by an age-related susceptibility or the presence of the sow as a primary source of MRSA CC398. Finally, transmission rates increased with the relative increase of the infection pressure within the pen compared to the total infection pressure, implying that within-pen transmission is a more important route compared to between-pen transmission and transmission through environmental exposure. Conclusion Our results indicate that MRSA CC398 is able to spread and persist in pig herds, resulting in an endemic situation. Transmission rates are affected by the use of selective antimicrobials and by the age of pigs

    Seroprevalence of SARS-CoV-2 antibodies among healthcare workers in Dutch hospitals after the 2020 first wave: a multicentre cross-sectional study with prospective follow-up

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    BackgroundWe aimed to estimate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence and describe its determinants and associated symptoms among unvaccinated healthcare workers (HCWs) after the first wave of the pandemic.MethodsHCWs from 13 Dutch hospitals were screened for antibodies against the spike protein of SARS-CoV-2 in June-July 2020 and after three months. Participants completed a retrospective questionnaire on determinants for occupational and community exposure to SARS-CoV-2 and symptoms suggestive of COVID-19 experienced since January 2020. The seroprevalence was calculated per baseline characteristic and symptom at baseline and after follow-up. Adjusted odds ratios (aOR) for seropositivity were determined using logistic regression.ResultsAmong 2328 HCWs, 323 (13.9%) were seropositive at enrolment, 49 of whom (15%) reported no previous symptoms suggestive of COVID-19. During follow-up, only 1% of the tested participants seroconverted. Seroprevalence was higher in younger HCWs compared to the mid-age category (aOR 1.53, 95% CI 1.07–2.18). Nurses (aOR 2.21, 95% CI 1.34–3.64) and administrative staff (aOR 1.87, 95% CI 1.02–3.43) had a higher seroprevalence than physicians. The highest seroprevalence was observed in HCWs in the emergency department (ED) (aOR 1.79, 95% CI 1.10–2.91), the lowest in HCWs in the intensive, high, or medium care units (aOR 0.47, 95% CI 0.31–0.71). Chronic respiratory disease, smoking, and having a dog were independently associated with a lower seroprevalence, while HCWs with diabetes mellitus had a higher seroprevalence. In a multivariable model containing all self-reported symptoms since January 2020, altered smell and taste, fever, general malaise/fatigue, and muscle aches were positively associated with developing antibodies, while sore throat and chills were negatively associated.ConclusionsThe SARS-CoV-2 seroprevalence in unvaccinated HCWs of 13 Dutch hospitals was 14% in June-July 2020 and remained stable after three months. A higher seroprevalence was observed in the ED and among nurses, administrative and young staff, and those with diabetes mellitus, while a lower seroprevalence was found in HCWs in intensive, high, or medium care, and those with self-reported lung disease, smokers, and dog owners. A history of altered smell or taste, fever, muscle aches and fatigue were independently associated with the presence of SARS-CoV-2 antibodies in unvaccinated HCWs.Medical Microbiolog

    Transmission of methicillin-resistant Staphylococcus aureus from food production animals to humans: a review

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    International surveillance of antimicrobial use in food animal production shows that methicillinresistant Staphylococcus aureus (MRSA), traditionally a human pathogen associated with hospitals, has emerged in the community and animals. Since 1961, MRSA has been causing human infections in hospitals worldwide and a vast majority of them were caused by five major epidemic clones. After 1990, other clones have emerged in the community, leading to infections in relatively young and healthy individuals. The origin of these clones is largely unknown, and extensive diversity among isolates exists. Companion animals have been indicated as a reservoir. However, most studies suggest that they are initially infected by humans and subsequently animals re-colonize humans. More recently, a new zoonotic reservoir in food production animals was found. This involves a specific clone, MRSA ST398, which spreads extensively in animals and is also found in retail meat. It poses a potential threat to public health, as people in contact with food production animals are at much higher risk of colonization. The most probable transmission route seems to be by (in)direct contact, as dust in stables was found positive for MRSA ST398. The role of MRSA ST398 as a food pathogen needs more research. To prevent colonization in humans, it is important to investigate transmission routes and transmission dynamics between animals, between animals and humans and between humans. Collaboration of human and veterinary epidemiologists and microbiologists is needed to identify the implications of this strain for public health and to develop cost-effective control strategies

    Transmission of methicillin-resistant Staphylococcus aureus from food production animals to humans: a review

    No full text
    International surveillance of antimicrobial use in food animal production shows that methicillinresistant Staphylococcus aureus (MRSA), traditionally a human pathogen associated with hospitals, has emerged in the community and animals. Since 1961, MRSA has been causing human infections in hospitals worldwide and a vast majority of them were caused by five major epidemic clones. After 1990, other clones have emerged in the community, leading to infections in relatively young and healthy individuals. The origin of these clones is largely unknown, and extensive diversity among isolates exists. Companion animals have been indicated as a reservoir. However, most studies suggest that they are initially infected by humans and subsequently animals re-colonize humans. More recently, a new zoonotic reservoir in food production animals was found. This involves a specific clone, MRSA ST398, which spreads extensively in animals and is also found in retail meat. It poses a potential threat to public health, as people in contact with food production animals are at much higher risk of colonization. The most probable transmission route seems to be by (in)direct contact, as dust in stables was found positive for MRSA ST398. The role of MRSA ST398 as a food pathogen needs more research. To prevent colonization in humans, it is important to investigate transmission routes and transmission dynamics between animals, between animals and humans and between humans. Collaboration of human and veterinary epidemiologists and microbiologists is needed to identify the implications of this strain for public health and to develop cost-effective control strategies

    Septic monoarthritis with isolation of P dagmatis as a monoculture in the stifle joint of a dog

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    A seven-month-old male cane corso was presented to our emergency clinic, with severe left hind lameness. The combination of history, physical examination, radiographs and cytology of the left stifle raised a suspicion of a septic monoarthritis. Bacteriology of the synovia confirmed an infection with Pasteurella dagmatis. Pasteurella species are frequently associated with skin disease and often isolated from dog bite wounds in humans. Isolation of P dagmatis only incidentally occurs and its frequency might be underestimated due to laboratory misidentification. Its pathogenicity remains unknown and is presumed to be equal to other Pasteurella species. However, in humans, this organism is associated with more serious disease, which might potentially also be the case in our patient. To the author’s knowledge, this is the first case report of a monoculture of P dagmatis isolated from the joint of a dog

    Septic monoarthritis with isolation of P dagmatis as a monoculture in the stifle joint of a dog

    No full text
    A seven-month-old male cane corso was presented to our emergency clinic, with severe left hind lameness. The combination of history, physical examination, radiographs and cytology of the left stifle raised a suspicion of a septic monoarthritis. Bacteriology of the synovia confirmed an infection with Pasteurella dagmatis. Pasteurella species are frequently associated with skin disease and often isolated from dog bite wounds in humans. Isolation of P dagmatis only incidentally occurs and its frequency might be underestimated due to laboratory misidentification. Its pathogenicity remains unknown and is presumed to be equal to other Pasteurella species. However, in humans, this organism is associated with more serious disease, which might potentially also be the case in our patient. To the author’s knowledge, this is the first case report of a monoculture of P dagmatis isolated from the joint of a dog
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