[Show abstract][Hide abstract] ABSTRACT: sec> Objectives In this pilot study within the Pretest 2 phase of the German National Cohort, we aimed to (1) test the hypothesis that distance and duration of travel to a study centre may affect participation rates and participants’ satisfaction and (2) to obtain data that would help to select recruitment areas around the study centre Hannover with the greatest projected participation rate for the main study. Setting Mixed urban/suburban environment in Northern Germany with approximately 600 000 inhabitants. 4 recruitment areas with divergent estimated mean distances (range, 7–40 km) and duration of travel to the study centre Hannover were selected. Participants 1050 men and women (ratio, 1:1), aged 20–69 years, were randomly selected from the population registries of the 4 recruitment areas and invited by mail to participate in the Pretest 2 study programme at the study centre Hannover, covering a variety of questionnaire-based and physical assessments. 166 individuals participated (16%). Interventions All 166 participants completed a travel questionnaire containing 5 items relating to travel duration and satisfaction, amounting to a participation rate of 100% in the questionnaire-based part of the study. Results Participation rates in the Pretest 2 programme at the study centre Hannover by area ranged from 11% (area farthest from the study centre, estimated median distance 38 km) to 18% (nearest area, 2 km). The odds of non-participation were highest in the area farthest from the study centre (adjusted OR 2.06; p=0.01; CI 1.28 to 3.32). Nonetheless, 97% of participants were satisfied with travel duration. Conclusions Increasing distance was associated with a lower participation rate. However, acceptance of duration of travel was high, irrespective of distance or duration. Thus, recruiting in farther away locations may select individuals with a greater frustration tolerance for travel to the study centre, perhaps due to a greater interest in participating in health-oriented studies and thus different health-related behaviour. </sec
BMJ Open 08/2015; 5(8). DOI:10.1136/bmjopen-2014-007461 · 2.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) have recently emerged in livestock and humans. Therefore, this study assessed the carriage of Enterobacteriaceae in the anterior nares and associated antimicrobial resistance in pig-exposed persons. Nasal swabs were enriched in non-selective broth and then plated on MacConkey and ESBL-selective agars. Species was confirmed by matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry (MALDI-ToF MS). Antimicrobial susceptibility testing was performed according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Of 114 pig-exposed persons tested, Enterobacteriaceae were detected in the nares of 76 (66·7%) participants. The predominant species were Proteus mirabilis (n = 17, 14·9%), Pantoea agglomerans (n = 13, 11·4%), Morganella morganii (n = 9, 7·9%), Citrobacter koseri (n = 9, 7·9%), Klebsiella pneumoniae, Escherichia coli and Proteus vulgaris (each n = 8, 7·0%). ESBL-E were not detected. Of all isolates tested, 3·4% were resistant against ciprofloxacin, 2·3% against gentamicin, 23·9% against trimethoprim-sulfamethoxazole and 44·3% against tigecycline. Despite the high prevalence of ESBL-E in livestock, pig-exposed persons did not carry ESBL-E in their nares. This finding is important, because colonization of the nasal reservoir might cause endogenous infections or facilitate transmission of ESBL-E in the general population.
Epidemiology and Infection 07/2015; -1:1-5. DOI:10.1017/S0950268815001776 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective was to establish and standardise a broth microdilution susceptibility testing method for porcine Bordetella (B.) bronchiseptica. B. bronchiseptica isolates from different geographical regions and farms were genotyped by macrorestriction analysis and subsequent pulsed-field gel electrophoresis. One reference and one type strain plus two field isolates of B. bronchiseptica were chosen to analyse growth curves in four different media: cation-adjusted Mueller-Hinton broth (CAMHB) with and without 2% lysed horse blood, Brain-Heart-Infusion (BHI), and Caso broth. The growth rate of each test strain in each medium was determined by culture enumeration and the suitability of CAMHB was confirmed by comparative statistical analysis. Thereafter, reference and type strain and eight epidemiologically unrelated field isolates of B. bronchiseptica were used to test the suitability of a broth microdilution susceptibility testing method following CLSI-approved performance standards given in document VET01-A4. Susceptibility tests, using 20 antimicrobial agents, were performed in five replicates, and data were collected after 20 and 24 hours incubation and statistically analysed. Due to the low growth rate of B. bronchiseptica, an incubation time of 24 hours resulted in significantly more homogeneous minimum inhibitory concentrations after five replications compared to a 20-hour incubation. An interlaboratory comparison trial including susceptibility testing of 24 antimicrobial agents revealed a high mean level of reproducibility (97.9%) of the modified method. Hence, in a harmonization for broth microdilution susceptibility testing of B. bronchiseptica, an incubation time of 24 hours in CAMHB medium with an incubation temperature of 35°C and an inoculum concentration of approximately 5 x 10(5) cfu/ml was proposed.
PLoS ONE 04/2015; 10(4):e0123883. DOI:10.1371/journal.pone.0123883 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To be able to analyze the relationship between the level of resistance and the use of antimicrobials, it is necessary to collect detailed data on antimicrobial usage. For this reason, data on antimicrobial use on 495 pig farms from entire Germany were collected and analyzed. In Germany, each application and dispensing of medicines to food-producing animals is documented in detail obligatorily by the veterinarian. This information was collected retrospectively for the year 2011. The analyses undertook separate examinations on the age groups sow, piglet, weaner and fattening pig; both the route of administration and indication per active ingredient, and active ingredient class, were evaluated. In total, 20,374 kg of antimicrobial substances were used in the study population. Tetracyclines were used in highest amounts, followed by beta-lactams, trimethoprim-sulfonamides and macrolides. Concerning the frequency of using an active substance per animal, polypeptides were most commonly administered. In all age groups, respiratory infections were the main indication for using antimicrobials, followed by intestinal diseases in piglets, weaners and fattening pigs and diseases of reproductive organs in sows. Over a period of 100 days, the median number of treatment days with one antimicrobial substance for piglets was 15 days, for weaners about 6 days, for fattening pigs about 4 days and for sows about 1 day. A multifactorial ANOVA was conducted to investigate which factors are associated with the treatment frequency. The factors "veterinarian" and "age group" were related to the treatment frequency, just as the interaction between "veterinarian" and "farm size" as well as the interaction between "veterinarian" and "age group".
PLoS ONE 03/2015; 10(3):e0119114. DOI:10.1371/journal.pone.0119114 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: SUMMARY To investigate risk factors for sporadic salmonellosis, for each notified case four randomly selected population controls matched for age, sex and geographical region were interviewed via self-administered questionnaire. Conditional logistic regression analysis of 285 matched pairs revealed significant associations for raw ground pork consumption [odds ratio (OR) 6·0, 95% confidence interval (CI) 1·8-20·1], taking antacids (OR 5·8, 95% CI 1·4-24·5), eating meat outside the home (OR 5·7, 95% CI 2·2-14·6) and daily changing or cleaning of dishcloth (OR 2·1, 95% CI 1·2-3·9). Animal contact and ice cream consumption were negatively associated with salmonellosis (OR 0·5, 95% CI 0·2-1 and OR 0·3, 95% CI 0·1-0·6, respectively). S. Typhimurium infections were significantly associated with raw ground pork consumption (OR 16·7, 95% CI 1·4-194·4) and S. Enteritidis infections with having travelled abroad (OR 9·7, 95% CI 2·0-47·3). Raw egg consumption was not a risk factor, substantiating the success of recently implemented national control programmes in the poultry industry. Unexpectedly, hygienic behaviour was more frequently reported by cases, probably because they overestimated their hygiene precautions retrospectively. Although animal contact might enhance human immunocompetence, underreporting of salmonellosis by pet owners could have occurred. Eating raw pork products is the major risk factor for sporadic human S. Typhimurium infections in Lower Saxony.
Epidemiology and Infection 01/2015; -1(13):1-9. DOI:10.1017/S0950268814003768 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Given veterinary students' varying mathematical knowledge and interest in statistics, teaching statistical concepts to them is often seen as a challenge. Consequently, there is an ongoing debate among lecturers about the best time to introduce the material into the curriculum, and the best thematic content and conceptual approach to teaching in basic biostatistics classes. During a workshop meeting of epidemiology and biostatistics lecturers of Austrian, German, and Swiss veterinary schools, the question was raised as to whether the topics taught in epidemiology and statistics classes are of sufficient relevance to our lecturing colleagues in other fields of veterinary education (i.e., whether our colleagues have certain expectations as to what the students should know about biostatistics before taking their classes). In 2012 an online survey was compiled and carried out at all eight German-speaking veterinary schools to address this issue. There were 266 respondents out of approximately 800 contacted lecturers from all schools and disciplines. Almost 50% responded that the basic biostatistics class should be taught early on (in the second or third year) while only 26% indicated that basic epidemiology should commence before the third year of the veterinary curriculum. There were clear differences in perceived relevance of the 44 epidemiological and biostatistical topics presented in the survey, assessed on a Likert scale from 0 (no relevance) to 4 (very high relevance). The results provide important information about how to revise the content of epidemiology and biostatistics classes, and the approach could also be used for other courses within the veterinary curriculum with a natural science focus.
Journal of Veterinary Medical Education 01/2015; 1(-1):1-13. DOI:10.3138/jvme.0314-029R2 · 0.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An exploratory study in five conventional pig production clusters was carried out to investigate the dynamic and diversity of Salmonella spp. within different production stages and sample site categories (pooled feces, direct and non-direct environment). Observing two production cycles per production cluster, a total of 1,276 samples were collected along the pig production chain. Following a microbiological examination via culture, 2,246 subcultures were generated out of 285 Salmonella positive samples and analysed by pheno- and genotyping methods. Based on a combination of serotyping, MLVA (multiple-locus variable-number tandem repeat (VNTR) analysis), PFGE (pulse-field gel electrophoresis) and MLST (multilocus sequence typing), an amount of 22.3% Salmonella positive samples were characterized in clonal lineages and its variants.
[Show abstract][Hide abstract] ABSTRACT: We examined (a) the fraction of and extent to which vaccinations were administered earlier than recommended (age-invalid) or with too short intervals between vaccine doses (interval-invalid) in countries of the World Health Organisation (WHO) African Region and (b) individual- and community-level factors associated with invalid vaccinations using multilevel techniques. Data from the Demographic and Health Surveys conducted in the last 10 years in 31 countries were used. Information about childhood vaccinations was based on vaccination records (n = 134,442). Invalid vaccinations (diphtheria, tetanus, pertussis [DTP1, DTP3] and measles-containing vaccine (MCV)) were defined using the WHO criteria. The median percentages of invalid DTP1, DTP3 and MCV vaccinations across all countries were 12.1% (interquartile range, 9.4–15.2%), 5.7% (5.0–7.6%), and 15.5% (10.0–18.1%), respectively. Of the invalid DTP1 vaccinations, 7.4% and 5.5% were administered at child's age of less than one and two weeks, respectively. In 12 countries, the proportion of invalid DTP3 vaccinations administered with an interval of less than two weeks before the preceding dose varied between 30% and 50%. In 13 countries, the proportion of MCV doses administered at child's age of less than six months varied between 20% and 45%. Community-level variables explained part of the variation in invalid vaccinations. Invalid vaccinations are common in African countries. Timing of childhood vaccinations should be improved to ensure an optimal protection against vaccine-preventable infections and to avoid unnecessary wastage in these economically deprived countries.
[Show abstract][Hide abstract] ABSTRACT: Campylobacter species belong to the most important foodborne bacteria which cause gastroenteritis in humans in both developed and developing countries. With increasing reporting rates, the public awareness towards Campylobacter infections is growing continuously. This strengthens the necessity to establish intervention measures for prevention and control of thermophilic Campylobacter spp. along the food chain, as in particular poultry and poultry meat represent a major source of human infections.
An interdisciplinary One Health approach and a combined effort of all stakeholders are necessary to ultimately reduce the burden of campylobacteriosis cases in humans. Numerous studies point out, however, that at present a complete elimination of Campylobacter in the food chain is not feasible. The present aim should therefore be to establish control measures and intervention strategies to minimize the occurrence of Campylobacter spp. in livestock (e.g. poultry flocks) and to reduce the quantitative Campylobacter burden in animals and foods. To this end, a combination of intervention methods at different stages of the food chain appears most promising. That has to be accompanied by targeted consumer advice and education campaigns to raise the awareness towards Campylobacter infections.
International Journal of Medical Microbiology 11/2014; DOI:10.1016/j.ijmm.2014.08.015 · 3.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background/objectives
The risk to die from an infectious disease in Germany has been continuously decreasing over the last century. Since infections are, however, not only causes of death but risk factors for diseases like cardiovascular diseases, it is essential to monitor and analyze their prevalence and frequency, especially in consideration of the increased life expectancy. To gain more knowledge about infectious diseases as risk factors and their implications on the condition and change of the immune status, the German National Cohort (GNC), a population-based prospective cohort study, will recruit 200,000 subjects between 2014 and 2017. In Pretest 1, a feasibility study for the GNC, we evaluated a self-administered and self-report questionnaire on infectious diseases and on the use of health care facilities (hereinafter called “ID Screen”) for feasibility and validity.
From August–November 2011, 435 participants between the ages of 20–69 completed the ID Screen. All subjects had been recruited via a random sample from the local residents’ registration offices by 4 of the 18 participating study centers. The questionnaire encompasses 77 variables in six sections assessing items such as 12-month prevalence of infections, cumulative prevalence of infectious diseases, visit of health care facilities and vaccination. The feasibility was amongst others evaluated by assessing the completeness and comprehensiveness of the questionnaire. To assess the questionnaires ability to measure “immune status” and “susceptibility to infections”, multivariate analysis was used.
The overall practicability was good and most items were well understood, demonstrated by 5 % of missing values. However, direct comparison of the items 12-month prevalence and lifetime prevalence of nephritis/pyelitis showed poor agreement and thereby poor understanding by 80 % of the participants, illustrating the necessity for a clear, lay person appropriate description of rare diseases to increase comprehensibility. The questionnaire will be used to support the assessment of immune dysfunction and frequency of infection. An analysis of these constructs in an exploratory factor analysis revealed limited applicability due to low interitem correlation (Cronbach’s α
[Show abstract][Hide abstract] ABSTRACT: Cats and dogs live in more than 20 % of German households and the contact between these pets and their owners can be very close. Therefore, a transmission of zoonotic pathogens may occur. To investigate whether zoonotic research questions can be examined in the context of population-based studies like the German National Cohort (GNC), two studies on different study populations were conducted as part of the feasibility tests of the GNC. The aim of the first study was to quantify the actual exposure of participants of the GNC to cats and dogs. In the second study summarised here the feasibility of the sampling of cats and dogs by their owners was tested. To quantify the exposure of participants of the GNC to cats and dogs 744 study participants of the Pretests of the GNC were asked whether they had contact with animals. Currently 10 % have a dog and 14 % have a cat in their household. These figures confirm that a large proportion of the German population has contact with pets and that there is a need for further zoonoses research. To establish the collection of biological samples from cats and dogs in the context of large-scale population-based studies feasible methods are needed. Therefore, a study was conducted to test whether pet owners can take samples from their cats and dogs and whether the quality of these samples is comparable to samples taken by a qualified veterinarian. A total of 82 dog and 18 cat owners were recruited in two veterinary practices in Hannover and the Clinic for Small Animals at the University of Veterinary Medicine in Hannover. Sampling instructions and sample material for nasal and buccal swabs, faecal samples and, in the case of cat owners, a brush for fur samples, were given to the pet owners. The pet owners were asked to take the samples from their pets at home and to send the samples by surface mail. Swab samples were cultured and bacterial growth was quantified independent of bacterial species. The growth of Gram-positive and Gram-negative bacteria from samples taken by the veterinarian and the pet owners were compared. For Gram-positive bacteria the agreement of laboratory results was 71 % for nasal swabs and 78 % for oral swabs while for Gram-negative bacteria the agreement of laboratory results was 55 % for nasal swabs and 87 % for oral swabs. In conclusion it has been shown that participants of the GNC are exposed to cats and dogs and that the sampling of cats and dogs by their owners is a feasible method which can be a useful tool for zoonoses research in population-based studies.
[Show abstract][Hide abstract] ABSTRACT: Extended-spectrum-beta-lactamase (ESBL) and plasmid-encoded cephamycinase (pAmpC) producing Escherichia (E.) coli in livestock farms have recently been matter of growing scientific and public concern. This article summarises selected European studies which focus on the prevalence and risk factors associated with the presence of such resistant E. coli isolates in livestock farms. Due to the different methodologies used in these studies, they cannot be compared directly; nonetheless, the overall prevalence found is very high. The prevalence found in broiler farms was higher than 40% and the individual animal prevalence was ca. 30%. The prevalence was more variable in pigs, with reports of pig farms showing prevalence of 1 to 80% and reports of individual animal prevalence of 15 to 100% In studies on cattle farms the production type as well as the age of animals had an influence on the number of positive samples. The highest prevalence was found with calves after birth and in the first weeks, whereas with older cattle the numbers of positive samples were considerably lower. Samples taken from dairy cows were positive more often after calving than before calving. According to the livestock species different risk factors may be assessed for the occurrence of ESBL/pAmpC-producing E. coli isolates. In some studies an association between the occurrence of ESBL-producing E. coli and factors like the use of antimicrobial agents or management factors, as the duration of the fattening period and the acquisition of animals from different origins, were identified. At the moment, there is a lack of systematic and standardised transnational epidemiological investigations on the occurrence of ESBL/pAmpC-producing E. coli in livestock. To control the further spread of ESBL/pAmpC-producing E. coli and the effectiveness of preventive measures, comprehensive monitoring and surveillance systems with harmonised methods are essential. Modern typing methods, in particular the sequence-based methods, can provide more information to clarify transmission pathways.
Berliner und Münchener tierärztliche Wochenschrift 09/2014; 127(9-10):403-11. DOI:10.2376/0005-9366-127-403 · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A cross-sectional study concerning farm prevalence and risk factors for the count of cefotaxime resistant Escherichia coli (E. coli) (CREC) positive samples per sampling group on German fattening pig farms was performed in 2011 and 2012. Altogether 48 farms in four agricultural regions in the whole of Germany were investigated. Faecal samples, boot swabs and dust samples from two sampling groups per farm were taken and supplemental data were collected using a questionnaire. On 85% of the farms, at least one sample contained cefotaxime resistant E. coli colonies. Positive samples were more frequent in faeces (61%) and boot swabs (54%) than in dust (11%). Relevant variables from the questionnaire were analysed in a univariable mixed effect Poisson regression model. Variables that were related to the number (risk) of positive samples per sampling group with a p-value < 0.2 were entered in a multivariable mixed effect Poisson regression model via backward selection. Factors that increased the risk for positive samples involved farm management and hygienic aspects. Farms that had a separate pen for diseased pigs had a 2.8 higher mean count of positive samples (95%-CI [1.71; 4.58], p = 0.001) than farms without an extra pen. The mean count was increased on farms with under-floor exhaust ventilation compared to farms with over-floor ventilation (2.22 [1.43; 3.46], p = 0.001) and more positive samples were observed on farms that controlled flies with toxin compared to farms that did not (1.86 [1.24; 2.78], p = 0.003). It can be concluded, that CREC are wide spread on German fattening pig farms. In addition the explorative approach of the present study suggests an influence of management strategies on the occurrence of cefotaxime resistant E. coli.
Preventive Veterinary Medicine 09/2014; 116(1-2). DOI:10.1016/j.prevetmed.2014.06.014 · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The presence of ESBL/AmpC-producing Enterobacteriaceae in healthy livestock, such as pigs, was frequently reported worldwide in the last years. The development and potential spread of these resistant microorganisms in farm animals is discussed critically. Therefore, the main objectives of this longitudinal study were to determine potential sources and prevalence dynamics of ESBL/AmpC-producing Escherichia coli in seven German ESBL/AmpC-positive conventional fattening pig farms in the course of the fattening period. Samples tested were taken at three different times within one finishing fattening period and included 20 individual faeces samples as well as various samples of the animals' housing environment such as pooled faeces, boot swabs, dust and environmental swabs. In individual faeces average carriage levels of 45%, 29% and 36% at the three sampling times were accompanied by decreasing faecal counts from 2.97 x 10(4) cfu/g at the first to 2.17 x 10(3) cfu/g at the third visit. In the animals' housing environment 47.6% of pooled faeces and boot swab samples respectively and 5.9% of environmental swabs but none of the dust samples were tested positive. Altogether 228 E. coli isolates were analysed by combination disc tests, PCR and partly via sequencing.Thereby, a novel gene bla(TEM-206) was detected. This study shows different detection levels of ESBL/AmpC-producing E. coli amongst the different farms and in the course of the fattening period. Pooled faeces and boot swab samples but not dust samples seem to be appropriate to assess the herd status of pigs with respect to ESBL/AmpC-producing Escherichia coli.
Berliner und Münchener tierärztliche Wochenschrift 09/2014; 127(9-10):412-9. DOI:10.2376/0005-9366-127-412 · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To appreciate the significance of sales data of antibiotics, data on antibiotic consumption (which were collected for selected food-producing animals within the representative VetCAb pilot study in Germany in 2011) were extrapolated for the total German animal population, and subsequently compared to the antibiotic sales data, which were collected throughout Germany in 2011 for the first time and which were published by the Federal Office of Consumer Protection and Food Safety (BVL). The extrapolation was realized based on the average dosage and the number of treatment units determined in the VetCAb pilot project for each active ingredient and animal species. It was extrapolated that 1302 tons of antimicrobial substances were consumed for treating cattle, pigs and broilers--this amount is accompanied by the amount of 1706 tons sold for all animal species. In Germany, tetracyclines and beta-lactams are the most commonly used and sold antimicrobial drugs. In third place are the potentiated sulfonamide, in fourth and fifth place, macrolides and polypeptides. To describe and evaluate the antibiotic usage for the several food-producing animals, detailed information is needed. Therefore, the number of treatments per active ingredient per animal and per day (treatment unit), and the number of treatment days per active ingredient per animal (treatment frequency) were calculated in the VetCAb project. These values represent scientifically collected orientation values for the treatment frequency of food-producing animal with antimicrobial substances in Germany. For example, a fattening pig is treated at 4.2 days (median) with one active ingredient within its 115-day fattening period. A dairy cow is treated at 3.5 days with one active ingredient within one year. A broiler is treated at 10 days with one active ingredient within its 39-day production period.
Berliner und Münchener tierärztliche Wochenschrift 09/2014; 127(9-10):366-74. DOI:10.2376/0005-9366-127-366 · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper summarizes statistical methods to describe susceptibility data. A frequent data basis in resistance studies are minimum inhibitory concentrations (MICs), measured for different antimicrobial agents. In the statistical context these (semi) quantitative MIC values are ordinal scaled. Therefore, they should be analysed with statistical tools appropriate for ordinal data. The resistance situation for each antimicrobial agent is often described using frequency distributions of MIC values. Resistance patterns can be described by frequencies of resistance profiles. More detailed insights into appearance and changes of simultaneous resistance against different agents are provided by a systematic analysis of dependency structure in susceptibility data. Furthermore, the calculation of differences between resistance profiles using appropriate distance measures enables the application of common methods of multivariate statistic for description and more complex analysis of susceptibility data. To improve the comparability of study results, it is desirable to present as much information as possible in a uniform way.
Berliner und Münchener tierärztliche Wochenschrift 09/2014; 127(9-10):349-58. DOI:10.2376/0005-9366-127-349 · 0.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Escherichia (E.) coli producing extended-spectrum beta-lactamases (ESBLs) are an increasing problem for public health. The success of ESBLs may be due to spread of ESBL-producing bacterial clones, transfer of ESBL gene-carrying plasmids or exchange of ESBL encoding genes on mobile elements. This makes it difficult to identify transmission routes and sources for ESBL-producing bacteria. The objectives of this study were to compare the distribution of genotypic and phenotypic properties of E. coli isolates from different animal and human sources collected in studies in the scope of the national research project RESET. ESBL-producing E. coli from two longitudinal and four cross-sectional studies in broiler, swine and cattle farms, a cross-sectional and a case–control study in humans and diagnostic isolates from humans and animals were used. In the RESET consortium, all laboratories followed harmonized methodologies for antimicrobial susceptibility testing, confirmation of the ESBL phenotype, specific PCR assays for the detection of blaTEM, blaCTX, and blaSHV genes and sequence analysis of the complete ESBL gene as well as a multiplex PCR for the detection of the four major phylogenetic groups of E. coli. Most ESBL genes were found in both, human and non-human populations but quantitative differences for distinct ESBL-types were detectable. The enzymes CTX-M-1 (63.3% of all animal isolates, 29.3% of all human isolates), CTX-M-15 (17.7% vs. 48.0%) and CTX-M-14 (5.3% vs. 8.7%) were the most common ones. More than 70% of the animal isolates and more than 50% of the human isolates contained the broadly distributed ESBL genes blaCTX-M-1, blaCTX-M-15, or the combinations blaSHV-12 + blaTEM or blaCTX-M-1 + blaTEM. While the majority of animal isolates carried blaCTX-M-1 (37.5%) or the combination blaCTX-M-1 + blaTEM (25.8%), this was the case for only 16.7% and 12.6%, respectively, of the human isolates. In contrast, 28.2% of the human isolates carried blaCTX-M-15 compared to 10.8% of the animal isolates.
When grouping data by ESBL types and phylogroups blaCTX-M-1 genes, mostly combined with phylogroup A or B1, were detected frequently in all settings. In contrast, blaCTX-M-15 genes common in human and animal populations were mainly combined with phylogroup A, but not with the more virulent phylogroup B2 with the exception of companion animals, where a few isolates were detectable.
When E. coli subtype definition included phylogenetic grouping and antimicrobial susceptibility data, the proportion of isolates allocated to common clusters was markedly reduced. Nevertheless, relevant proportions of same subtypes were detected in isolates from the human and livestock and companion animal populations included in this study, suggesting exchange of bacteria or bacterial genes between these populations or a common reservoir. In addition, these results clearly showed that there is some similarity between ESBL genes, and bacterial properties in isolates from the different populations. Finally, our current approach provides good insight into common and population-specific clusters, which can be used as a basis for the selection of ESBL-producing isolates from interesting clusters for further detailed characterizations, e.g. by whole genome sequencing.
International Journal of Medical Microbiology 08/2014; 304(7). DOI:10.1016/j.ijmm.2014.07.015 · 3.61 Impact Factor