Biochemical and molecular characterization of Campylobacter fetus isolates from bulls subjected to bovine genital campylobacteriosis diagnosis in Spain

BACKGROUND

Bovine genital campylobacteriosis (BGC) is caused by Campylobacter fetus subsp. venerealis (Cfv) including its biovar intermedius (Cfvi). This sexually transmitted disease induces early reproductive failure causing considerable economic losses in the cattle industry. Using a collection of well-characterized isolates (n = 13), C. fetus field isolates (n = 64) and saprophytic isolates resembling Campylobacter (n = 75) obtained from smegma samples of breeding bulls, this study evaluated the concordance of the most used phenotypic (H2S production in cysteine medium and 1% glycine tolerance) and molecular (PCR) methods for the diagnosis of BGC and assessed possible cross-reactions in the molecular diagnostic methods.

RESULTS

Characterization at the subspecies level (fetus vs. venerealis) of C. fetus isolated from bull preputial samples using phenotypic and molecular (PCR targeting nahE and ISCfe1) methods showed moderate concordance (κ = 0.462; CI: 0.256-0.669). No cross-reactions were observed with other saprophytic microaerophilic species or with other Campylobacter species that can be present in preputial samples. Whole genome sequencing (WGS) of discrepant isolates showed 100% agreement with PCR identification. For the differentiation of Cfv biovars, comparison of the H2S test (at 72 h and 5 days of incubation) and a PCR targeting the L-cysteine transporter genes showed higher concordance when H2S production was assessed after 5 days (72 h; κ = 0.553, 0.329-0.778 CI vs. 5 days; κ = 0.881, 0.631-1 CI), evidencing the efficacy of a longer incubation time.

CONCLUSIONS

This study confirmed the limitations of biochemical tests to correctly identify C. fetus subspecies and biovars. However, in the case of biovars, when extended incubation times for the H2S test (5 days) were used, phenotypic identification results were significantly improved, although PCR-based methods produced more accurate results. Perfect agreement of WGS with the PCR results and absence of cross-reactions with non-C. fetus saprophytic bacteria from the smegma demonstrated the usefulness of these methods. Nevertheless, the identification of new C. fetus subspecies-specific genes would help to improve BGC diagnosis.

Coxiella burnetii infection persistence in a goat herd during seven kidding seasons after an outbreak of abortions: the effect of vaccination

Coxiella burnetii infection was monitored during seven kidding seasons (2017-2023) in a dairy goat herd that after an outbreak of Q fever abortions was vaccinated with an inactivated phase I vaccine. Due to the high infection rate just after the outbreak, only the replacement stock was vaccinated during the first three kidding seasons, and when the average herd immunity had decreased (fourth kidding season onwards), the whole herd was vaccinated. Vaginal swabs, feces, and milk were analyzed by PCR to monitor infection, and dust and aerosols were analyzed to measure C. burnetii environmental contamination. One year after the onset of the outbreak, a significant reduction in C. burnetii shedding loads was observed, but the percentage of shedding animals remained high until the third kidding season. By the seventh kidding season, no shedders were detected. The bacterial load excreted was significantly lower in vaccinated compared with unvaccinated animals, and in yearlings compared with multiparous. C. burnetii was detected by PCR in aerosols collected inside the animal premises throughout the study period except in the last season; whereas, aerosols collected outdoors tested negative in the last three kidding seasons. Viable C. burnetii was detectable in environmental dust collected inside the barn until the third kidding season following the outbreak. These results indicate that after an outbreak of Q fever, the risk of infection for humans and susceptible animals can remain high for at least three kidding seasons when the number of C. burnetii animal shedders is still high, even when bacterial excretion is low.

IMPORTANCE

Q fever is a zoonosis distributed worldwide. Ruminants are the main reservoir, and infection can cause high rates of abortion. After entering a farm, Coxiella burnetii infection can persist in the animal population over several lambing/kidding periods. Once infection is established in a herd, vaccination with the inactivated Phase I vaccine significantly reduces bacterial shedding, but although at low levels, excretion may continue to occur for several lambing/kidding seasons. The time that C. burnetii remains viable in the farm environment after an outbreak of Q fever determines the period when risk of infection is high for the people in close contact. This work showed that this period extends at least three kidding seasons after the outbreak. These results provided valuable information on the epidemiology of C. burnetii infection in goat herds and may help to develop guidelines for controlling the disease and reducing infection risk for susceptible people and animals.

Comparative pangenomic analysis of Campylobacter fetus isolated from Spanish bulls and other mammalian species

Campylobacter fetus comprises two closely related mammal-associated subspecies: Campylobacter fetus subsp. fetus (Cff) and Campylobacter fetus subsp. venerealis (Cfv). The latter causes bovine genital campylobacteriosis, a sexually-transmitted disease endemic in Spain that results in significant economic losses in the cattle industry. Here, 33 C. fetus Spanish isolates were whole-genome sequenced and compared with 62 publicly available C. fetus genomes from other countries. Genome-based taxonomic identification revealed high concordance with in silico PCR, confirming Spanish isolates as Cff (n = 4), Cfv (n = 9) and Cfv biovar intermedius (Cfvi, n = 20). MLST analysis assigned the Spanish isolates to 6 STs, including three novel: ST-76 and ST-77 for Cfv and ST-78 for Cff. Core genome SNP phylogenetic analysis of the 95 genomes identified multiple clusters, revealing associations at subspecies and biovar level between genomes with the same ST and separating the Cfvi genomes from Spain and other countries. A genome-wide association study identified pqqL as a Cfv-specific gene and a potential candidate for more accurate identification methods. Functionality analysis revealed variations in the accessory genome of C. fetus subspecies and biovars that deserve further studies. These results provide valuable information about the regional variants of C. fetus present in Spain and the genetic diversity and predicted functionality of the different subspecies.

Whole-genome long-read sequencing to unveil Enterococcus antimicrobial resistance in dairy cattle farms exposed a widespread occurrence of Enterococcus lactis

Enterococcus faecalis (Efs) and Enterococcus faecium (Efm) are major causes of multiresistant healthcare-associated or nosocomial infections. Efm has been traditionally divided into clades A (healthcare associated) and B (community associated) but clade B has been recently reassigned to Enterococcus lactis (Elc). However, identification techniques do not routinely differentiate Elc from Efm. As part of a longitudinal study to investigate the antimicrobial resistance of Enterococcus in dairy cattle, isolates initially identified as Efm were confirmed as Elc after Oxford-Nanopore long-fragment whole-genome sequencing and genome comparisons. An Efm-specific PCR assay was developed and used to identify isolates recovered from animal feces on five farms, resulting in 44 Efs, 23 Efm, and 59 Elc. Resistance, determined by broth microdilution, was more frequent in Efs than in Efm and Elc but all isolates were susceptible to ampicillin, daptomycin, teicoplanin, tigecycline, and vancomycin. Genome sequencing analysis of 32 isolates identified 23 antimicrobial resistance genes (ARGs, mostly plasmid-located) and 2 single nucleotide polymorphisms associated with resistance to 10 antimicrobial classes, showing high concordance with phenotypic resistance. Notably, linezolid resistance in Efm was encoded by the optrA gene, located in plasmids downstream of the fexA gene. Although most Elc lacked virulence factors and genetic determinants of resistance, one isolate carried a plasmid with eight ARGs. This study showed that Elc is more prevalent than Efm in dairy cattle but carries fewer ARGs and virulence genes. However, Elc can carry multi-drug-resistant plasmids like those harbored by Efm and could act as a donor of ARGs for other pathogenic enterococcal species.IMPORTANCEEnterococcus species identification is crucial due to differences in pathogenicity and antibiotic resistance profiles. The failure of traditional methods or whole-genome sequencing-based taxonomic classifiers to distinguish Enterococcus lactis (Elc) from Enterococcus faecium (Efm) results in a biased interpretation of Efm epidemiology. The Efm species-specific real-time PCR assay developed here will help to properly identify Efm (only the formerly known clade A) in future studies. Here, we showed that Elc is prevalent in dairy cattle, and although this species carries fewer genetic determinants of resistance (GDRs) than Enterococcus faecalis (Efs) and Efm, it can carry multi-drug-resistant (MDR) plasmids and could act as a donor of resistance genes for other pathogenic enterococcal species. Although all isolates (Efs, Efm, and Elc) were susceptible to critically or highly important antibiotics like daptomycin, teicoplanin, tigecycline, and vancomycin, the presence of GDRs in MDR-plasmids is a concern since antimicrobials commonly used in livestock could co-select and confer resistance to critically important antimicrobials not used in food-producing animals.

Monitoring within-farm transmission dynamics of antimicrobial-resistant Campylobacter in dairy cattle using broth microdilution and long-read whole genome sequencing

Campylobacter jejuni and Campylobacter coli are important foodborne zoonotic pathogens and cause for concern due to the increasing trend in antimicrobial resistance. A long-run surveillance study was conducted in animals from different age groups in five dairy cattle farms to investigate the within-farm diversity and transmission dynamics of resistant Campylobacter throughout time. The resistance phenotype of the circulating isolates (170 C. jejuni and 37 C. coli) was determined by broth microdilution and a selection of 56 isolates were whole genome sequenced using the Oxford-Nanopore long-fragment sequencing technology resulting in completely resolved and circularized genomes (both chromosomes and plasmids). C. jejuni was isolated from all farms while C. coli was isolated from only two farms, but resistance rates were higher in C. coli than in C. jejuni and in calves than in adult animals. Some genotypes (e.g. ST-48, gyrA_T86I/tet(O)/blaOXA-61 in farm F1; ST-12000, aadE-Cc/tet(O)/blaOXA-489 in F4) persisted throughout the study while others were only sporadically detected. Acquisition of extracellular genes from other isolates and intracellular mutational events were identified as the processes that led to the emergence of the resistant genotypes that spread within the herds. Monitoring with Oxford Nanopore Technologies sequencing helped to decipher the complex molecular epidemiology underlying the within-farm dissemination of resistant Campylobacter.

A Q fever outbreak among visitors to a natural cave, Bizkaia, Spain, December 2020 to October 2021

We describe a large Q fever outbreak reported in Spain, including 108 cases, 53 with pneumonia and 27 requiring hospitalisations. The first cases were detected in February 2021 among rock climbers visiting a cave in Bizkaia, and the last case was detected in October 2021. Most cases were notified after the Easter holiday (April-May 2021). More males (63.9%) than females (36.1%) were infected (median ages: 42 (1-68) and 39 years (6-61), respectively). We detected Coxiella burnetii by PCR in faecal, dust and/or aerosol samples taken inside the cave in March 2021, and in dust and aerosol samples collected between March 2021 and February 2023. Coxiella burnetii from dust samples were cultured on Vero cells, showing viability for 24 months. Based on serological and genotyping data, goats sheltering in the cave were the most likely source of infection. The cave was closed on 29 April 2021, movements of goats and sheep in the area were restricted (March-July 2021), and the animals were vaccinated in October 2021. Investigation of Q fever outbreaks requires a multidisciplinary One Health approach as these outbreaks can occur in unexpected places like natural sites where animals are present.

Long-Term In Vitro Adhesive Properties of Two Universal Adhesives to Dentin

The composition of universal adhesives, as well as the adhesive strategy, may influence bonding effectiveness and durability. This study aimed to evaluate the microtensile bond strength (µTBS) and nanoleakage (NL), immediately and after 6-month aging, and in situ degree of conversion (DC), of two universal adhesives (Scotchbond Universal Adhesive, SBU; Xeno Select, XEN) applied with etch-and-rinse (ER) and self-etch (SE) strategies, in comparison with a two-step SE adhesive (Clearfil SE Bond, CSE). Dentin surfaces of fifty human third molars were randomly assigned to the following adhesives: two universal adhesives, SBU and XEN, applied in ER or SE mode and CSE, used as control. Teeth were sectioned into beams to be tested under µTBS, half of them after 24 h, and the rest after 6 months of water aging. Selected beams from each tooth were used for NL evaluation and in situ DC quantification. SBU and CSE showed significantly higher mean µTBS and lower nanoleakage than XEN, regardless of the evaluation time and adhesion strategy. XEN-SE yielded the lowest degree of conversion. Therefore, adhesive properties of universal adhesives to dentin are material dependent, regardless of the adhesion strategy, exhibiting XEN a significantly worse performance than SBU.

Within-farm dynamics of ESBL-producing Escherichia coli in dairy cattle: Resistance profiles and molecular characterization by long-read whole-genome sequencing

A longitudinal study was designed in five dairy cattle farms to assess the within-farm dynamics of ESBL-/AmpC-/carbapenemase-producing E. coli and their resistance profiles, along with the genes conferring the resistance phenotypes. Twelve samplings were performed over a period of 16 months, collecting rectal feces from apparently healthy animals in three age groups (calves, heifers, and lactating cows) that were subjected to selective isolation in cefotaxime-containing media. Minimum inhibitory concentrations were determined by broth microdilution for 197 cefotaxime-resistant E. coli (1–3 isolates per age group and sampling date), and 41 of them were selected for long-read whole-genome sequencing. Cefotaxime-resistant E. coli were detected in the five farms, but isolation frequency and resistance profiles varied among farms and age groups. The genetic profiling of a selection of isolates recovered in two of the farms was described in full detail, showing the predominance of a few genomic subtypes of E. coli in one farm (F1) and great variability of strains in another one (F4). Two predominant distinct strains carrying the blaCTX-M-1 gene in IncX1 plasmids successively spread and persisted in F1 over a prolonged period. In F4, 13 different MLST types carrying a high diversity of ESBL-encoding genes in 6 different plasmid types were observed, probably as the result of multiple source contamination events. In both farms, the presence of certain plasmid types with the same repertoire of ARGs in different E. coli STs strongly suggested the occurrence of horizontal transfer of such plasmids among strains circulating within the farms. Considering the public health importance of ESBL-producing E. coli both as pathogens and as vectors for resistance mechanisms, the presence of β-lactamase- and other AMR-encoding genes in plasmids that can be readily transferred between bacteria is a concern that highlights the need for One Health surveillance.

Mechanical life support algorithm developed by simulation for inpatient emergency management of recipients of implantable left ventricular assist devices

Background

Published guidance concerning emergency management of left ventricular assist device (LVAD) recipients is both limited and lacking in consensus which increases the risk of delayed and/or inappropriate actions.

Methods

In our specialist tertiary referral centre we developed, by iteration, a novel in-hospital resuscitation algorithm for LVAD emergencies which we validated through simulation and assessment of our multi-disciplinary team. A Mechanical Life Support course was established to provide theoretical and practical education combined with simulation to consolidate knowledge and confidence in algorithm use. We assessed these measures using confidence scoring, a key performance indicator (the time taken to restart LVAD function) and a multiple-choice question (MCQ) examination.

Results

The mean baseline staff confidence score in management of LVAD emergencies was 2.4 ± 1.2 out of a maximum of 5 (n = 29). After training with simulation, mean confidence score increased to 3.5 ± 0.8 (n = 13).

Clinical personnel who were provided with the novel resuscitation algorithm were able to reduce time taken to restart LVAD function from a mean value of 49 ± 8.2 seconds (pre-training) to 20.4 ± 5 seconds (post-training) (n = 42, p < 0.0001).

The Mechanical Life Support course increased mean confidence from 2.5 ± 1.2 to 4 ± 0.6 (n = 44, p < 0.0001) and mean MCQ score from 18.7 ± 3.4 to 22.8 ± 2.6, out of a maximum of 28 (n = 44, p < 0.0001).

Conclusion

We present a simplified LVAD Advanced Life Support algorithm to aid the crucial first minutes of resuscitation where basic interventions are likely to be critical in assuring good patient outcomes.

An international evaluation of biosecurity management capacity in the seaweed aquaculture industry

Seaweeds form the second largest global aquaculture product in volume, and despite rapid growth of the sector over the last 25 years, production and quality in top producing regions is becoming increasingly limited due to disease and pest outbreaks, the spread of non-native cultivars and the degradation of genetic health due to inbreeding. Most notably, the lack of biosecurity measures leading to disease and pest outbreaks are reported to cause the most significant production losses in the seaweed industry. This study uses the Knowledge, Attitude and Practice (KAP) survey tool to quantify and compare biosecurity cross-culturally, in two major red seaweed producing countries, the Philippines and Tanzania. Both countries have significantly different political contexts and the seaweed sector sits within two very different value chains. Seaweed-based commodities from these countries, however, enters the same international market for carrageenan, a thickening agent used for a variety of products globally. This study uses the KAP survey tool to assess currently-adopted biosecurity control measures and understand how potential policy strategies could be developed on an international scale. Farmers from both producing countries have good biosecurity knowledge. In Tanzania 64% farmers scored Fair or Good, and in the Philippines this was 95%. Corresponding scores in practices were lower, 85% Poor for Tanzania, and 88% Fair for the Philippines, indicating there is a lack of resources for farmers to implement additional practices. The information gathered using the KAP tool in the context of the global seaweed industry can be used to facilitate compromise between science, policy and practice whilst taking into consideration smaller-scale regional challenges. Given the results from the seaweed industry were similar to that of smallholder agricultural sectors, it is suggested that governmental programs to incentivise biosecurity in smallholder rural agriculture could be adapted for the seaweed industry. This study also demonstrates the potential use of the KAP survey, as a tool to accurately compare biosecurity challenges faced by farmers in different aquaculture sectors globally, and to encourage alignment in international approaches to aquaculture biosecurity policies.

Analysis of environmental dust in goat and sheep farms to assess Coxiella burnetii infection in a Q fever endemic area: Geographical distribution, relationship with human cases and genotypes

Real-time PCR analysis of environmental samples (dust and aerosols) is an easy tool to investigate the presence of Coxiella burnetii in the farm environment. The aim of this study was to assess the distribution of C. burnetii DNA in dust collected inside animal premises from 272 small ruminant farms in Bizkaia (northern Spain), a region with recent reports of human Q fever cases and outbreaks. Within each farm, 5 samples of dust were collected from difference surfaces, and data on animal census, management procedures, characteristics of the premises and geographic location were collected. Real-time PCR analysis of the dust samples detected presence of C. burnetii DNA in 98 farms (36.0%), flock-prevalence being higher in sheep (38.9%) or mixed ovine-caprine production systems (36.8%), compared to goats (25.0%). Larger bacterial burdens were observed in mixed farms, compared to sheep (p < .05). Single nucleotide polymorphism (SNP) analysis identified 5 different genotypes, with SNP8 being the predominant genotype (73%), followed by SNP6 (11%), SNP2 (9%), SNP4 (5%) and SNP1 (2%). Proportion of farms where C. burnetii DNA was detected differed among the different agricultural counties, and a higher proportion of C. burnetii DNA positive farms was associated with the occurrence of recent human Q fever outbreaks at several geographical locations. Dust sampling in domestic ruminant farms coupled with real-time PCR to screen for the presence of C. burnetii and estimate bacterial load can be a useful tool to identify herds and regions with high prevalence, define priority actions and monitor the effect of control measures. If combined with molecular genotyping and spatial distribution maps, it can help to identify farm contamination sources and trace the origin of human outbreaks.

One Health Approach: An Overview of Q Fever in Livestock, Wildlife and Humans in Asturias (Northwestern Spain)

This study aimed to investigate the seroprevalence of C. burnetii in domestic ruminants, wild ungulates, as well as the current situation of Q fever in humans in a small region in northwestern Spain where a close contact at the wildlife-livestock-human interface exists, and information on C. burnetii infection is scarce. Seroprevalence of C. burnetii was 8.4% in sheep, 18.4% in cattle, and 24.4% in goats. Real-time PCR analysis of environmental samples collected in 25 livestock farms detected Coxiella DNA in dust and/or aerosols collected in 20 of them. Analysis of sera from 327 wild ungulates revealed lower seroprevalence than that found in domestic ruminants, with 8.4% of Iberian red deer, 7.3% chamois, 6.9% fallow deer, 5.5% European wild boar and 3.5% of roe deer harboring antibodies to C. burnetii. Exposure to the pathogen in humans was determined by IFAT analysis of 1312 blood samples collected from patients admitted at healthcare centers with Q fever compatible symptoms, such as fever and/or pneumonia. Results showed that 15.9% of the patients had IFAT titers ≥ 1/128 suggestive of probable acute infection. This study is an example of a One Health approach with medical and veterinary institutions involved in investigating zoonotic diseases.

Whole genome-based characterisation of antimicrobial resistance and genetic diversity in Campylobacter jejuni and Campylobacter coli from ruminants

Campylobacter, a leading cause of gastroenteritis in humans, asymptomatically colonises the intestinal tract of a wide range of animals.Although antimicrobial treatment is restricted to severe cases, the increase of antimicrobial resistance (AMR) is a concern. Considering the significant contribution of ruminants as reservoirs of resistant Campylobacter, Illumina whole-genome sequencing was used to characterise the mechanisms of AMR in Campylobacter jejuni and Campylobacter coli recovered from beef cattle, dairy cattle, and sheep in northern Spain. Genome analysis showed extensive genetic diversity that clearly separated both species. Resistance genotypes were identified by screening assembled sequences with BLASTn and ABRicate, and additional sequence alignments were performed to search for frameshift mutations and gene modifications. A high correlation was observed between phenotypic resistance to a given antimicrobial and the presence of the corresponding known resistance genes. Detailed sequence analysis allowed us to detect the recently described mosaic tet(O/M/O) gene in one C. coli, describe possible new alleles of blaOXA-61-like genes, and decipher the genetic context of aminoglycoside resistance genes, as well as the plasmid/chromosomal location of the different AMR genes and their implication for resistance spread. Updated resistance gene databases and detailed analysis of the matched open reading frames are needed to avoid errors when using WGS-based analysis pipelines for AMR detection in the absence of phenotypic data.

NEUTRON NOISE PATTERNS FROM COUPLED FUEL-ASSEMBLY VIBRATIONS

The neutron flux fluctuation magnitude of KWU-built PWRs shows a hitherto unexplained correlation with the types of loaded fuel assemblies. Also, certain measured long-range neutron flux fluctuation patterns in neighboring core quadrants still lack a closed understanding of their origin. The explanation of these phenomena has recently revived a new interest in neutron noise research.

The contribution at hand investigates the idea that a synchronized coolant-driven vibration of major parts of the fuel-assembly ensemble leads to these phenomena. Starting with an assumed mode of such collective vibration, the resulting effects on the time-dependent neutron-flux distribution are analyzed via a DYN3D simulation. A three-dimensional representation of the time-dependent bow of all fuel assemblies is taken into account as a nodal DYN3D feedback parameter by time-dependent variations of the fuel-assembly pitch. The impact of its variation on the cross sections is quantified using a cross-section library that is generated from the output of corresponding CASMO5 calculations.

The DYN3D simulation qualitatively reproduces the measured neutron-flux fluctuation patterns. The magnitude of the fluctuations and its radial dependence are comparable to the measured details. The results imply that collective fuel-assembly vibrations are a promising candidate for being the key to understand long-known fluctuation patterns in KWU built PWRs. Further research should elaborate on possible excitation mechanisms of the assumed vibration modes.

Monitoring Coxiella burnetii Infection in Naturally Infected Dairy Sheep Flocks Throughout Four Lambing Seasons and Investigation of Viable Bacteria

Progression of Coxiella burnetii infection in four naturally infected sheep flocks, and in their farm environment, was monitored throughout four lambing seasons. Flocks with an active infection were selected based on the presence of C. burnetii DNA in bulk-tank milk (BTM) and a high seroprevalence in yearlings during the previous milking period (Spring 2015). During four consecutive lambing seasons (2015/16–2018/19), samples were collected within 1 week after each lambing period from animals (vaginal swabs, milk and feces from ewes, and yearlings) and the environment (dust indoor sheep premises). BTM samples and aerosols (outdoors and indoors) were monthly collected between lambing and the end of milking. Real-time PCR analyses showed different trends in C. burnetii shedding in the flocks, with a general progressive decrease in bacterial shedding throughout the years, interrupted in three flocks by peaks of reinfection associated with specific management practices. A significant relationship was found between C. burnetii fecal shedding and the bacterial burden detected in dust, whereas shedding by vaginal route affected the detection of C. burnetii in indoor aerosols. Three genotypes were identified: SNP8 (three flocks, 52.9% of the samples), SNP1 (two flocks, 44.8% samples), and SNP5 (one flock, two environmental samples). Coxiella burnetii viability in dust measured by culture in Vero cells was demonstrated in two of the flocks, even during the fourth lambing season. The results showed that infection can remain active for over 5 years if effective control and biosafety measures are not correctly implemented.

Naturally Avian Influenza Virus-Infected Wild Birds Are More Likely to Test Positive for Mycobacterium spp. and Salmonella spp

Wild birds often harbor infectious microorganisms. Some of these infectious microorganisms may present a risk to domestic animals and humans through spillover events. Detections of certain microorganisms have been shown to increase host susceptibility to infections by other microorganisms, leading to coinfections and altered host-to-host transmission patterns. However, little is known about the frequency of coinfections and its impact on wild bird populations. In order to verify whether avian influenza virus (AIV) natural infection in wild waterbirds was related to the excretion of other microorganisms, 73 AIV-positive samples (feces and cloacal swabs) were coupled with 73 AIV-negative samples of the same sampling characteristics and tested by real-time PCR specific for the following microorganisms: West Nile virus, avian avulavirus 1, Salmonella spp., Yersinia enterocolitica, Yersinia pseudotuberculosis, Mycobacterium avium subspecies, Mycobacterium tuberculosis complex, and Mycobacterium spp. Concurrent detections were found in 47.9% (35/73) of the AIV-positive samples and in 23.3% (17/73) of the AIV-negative samples (P = 0.003). Mycobacterium spp. and Salmonella spp. were found to be significantly more prevalent among the AIV-positive samples than among the AIV-negative samples (42.9% vs. 22.8%; P = 0.024 and 15.2% vs. 0.0%; P = 0.0015, respectively). Prevalence of concurrent detections differed significantly among sampling years (P = 0.001), host families (P = 0.002), host species (P = 0.003), AIV subtypes (P = 0.003), and type of sample (P = 0.009). Multiple concurrent detections (more than one of the tested microorganisms excluding AIV) were found in 9.6% (7/73) of all the AIV-positive samples, accounting for 20% (7/35) of the concurrent detection cases. In contrast, in AIV-negative samples we never detected more than one of the selected microorganisms. These results show that AIV detection was associated with the detection of the monitored microorganisms. Further studies of a larger field sample set or under experimental conditions are necessary to infer causality in these trends.

A Q fever outbreak associated to courier transport of pets

On August 3rd, 2017, a Q fever outbreak alert was issued at a courier company that in addition to urgent freight transport offered pet delivery services. The epidemiological investigation set the exposition period between June 1 and August 8. In this period, 180 workers from two operational platforms for parcel distribution located in two provinces of the Basque Country (Bizkaia and Araba) were exposed; 64 filled a questionnaire and provided blood samples for serological testing, resulting in 10 confirmed cases (15.6%) and six (9.4%) probable cases. Nine workers (8 confirmed and 1 probable) showed Q fever symptoms, including pneumonia (five cases), and required medical care services, including one hospital admission. The attack rate was 25% (16/64), being higher among workers that visited the Bizkaia platform. This suggested that the origin of the outbreak was in the Bizkaia platform, where animals in transit waited at a pet holding site until being moved to their destination. Environmental samples consisting on 19 surface dust and two aerosol samples were collected at the Bizkaia platform to investigate the presence of C. burnetti DNA. All dust samples were positive by real time PCR, the lowest Ct values being found in dust collected at the pet holding facilities, and therefore suggesting that contamination originated at the pet holding site. The genotype identified in dust was SNP1/MST13, one of the most commonly identified genotypes in goats and sheep in the Basque Country. During the exposure period, two deliveries of miniature goats were made, of which only one could be investigated and tested negative. Although the contamination source could not be unequivocally identified, transport of ruminants was banned at the company, and Q fever was included among the occupational-associated health risks.

Optimal duration of first-line chemotherapy for advanced gastric cancer: data from the AGAMENON registry

BACKGROUND

The optimal duration of first-line chemotherapy for patients with advanced gastric cancer is unknown. Diverse clinical trials have proposed different strategies including limited treatment, maintenance of some drugs, or treatment until progression.

METHOD

The sample comprises patients from the AGAMENON multicenter registry without progression after second evaluation of response. The objective was to explore the optimal duration of first-line chemotherapy. A frailty multi-state model was conducted.

RESULTS

415 patients were divided into three strata: discontinuation of platinum and maintenance with fluoropyrimidine until progression (30%, n = 123), complete treatment withdrawal prior to progression (52%, n = 216), and full treatment until progression (18%, n = 76). The hazard of tumor progression decreased by 19% per month with the full treatment regimen. However, we found no evidence that fluoropyrimidine maintenance (hazard ratio [HR] 1.07, confidence interval [CI] 95%, 0.69-1.65) worsened progression-free survival (PFS) with respect to treatment until progression. Predictive factors for PFS were ECOG performance status, ≥ 3 metastatic sites, prior tumor response, and bone metastases. Toxicity grade 3/4 was more common in those who continued the full treatment until progression vs fluoropyrimidine maintenance (16% vs 6%).

CONCLUSION

The longer duration of the full initial regimen exerted a protective effect on the patients of this registry. Platinum discontinuation followed by fluoropyrimidine maintenance yields comparable efficacy to treatment up to PD, with a lower rate of serious adverse events.

Occurrence of Campylobacter jejuni and Campylobacter coli in Cattle and Sheep in Northern Spain and Changes in Antimicrobial Resistance in Two Studies 10-years Apart

A cross-sectional survey was conducted in 2014-2016 in 301 ruminant herds to estimate C. jejuni and C. coli prevalence, and investigate their susceptibility to antimicrobials. Risk of shedding C. jejuni was higher in cattle than sheep (81.2% vs. 45.2%; ORadj = 5.22, p < 0.001), whereas risk of shedding C. coli was higher in sheep than in cattle (19.1% vs. 11.3%; ORadj = 1.71, p = 0.128). Susceptibility to six antimicrobials was determined by broth microdilution using European Committee for Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off values. C. coli exhibited higher resistance (94.1%, 32/34) than C. jejuni (65.1%, 71/109), and resistance was more widespread in isolates from dairy cattle than beef cattle or sheep. Compared to results obtained 10-years earlier (2003-2005) in a similar survey, an increase in fluoroquinolone-resistance was observed in C. jejuni from beef cattle (32.0% to 61.9%; OR = 3.45, p = 0.020), and a decrease in tetracycline-resistance in C. jejuni from dairy cattle (75.0% to 43.2%; OR = 0.25, p = 0.026). Resistance to macrolides remained stable at low rates and restricted to C. coli from dairy cattle, with all macrolide-resistant C. coli showing a pattern of pan-resistance. Presence of the single nucleotide polymorphisms (SNPs) associated to quinolone and macrolide resistance was confirmed in all phenotypically resistant isolates. The increase in fluoroquinolone resistance is worrisome but susceptibility to macrolides is reassuring.

Multilayer intraclonal heterogeneity in chronic myelomonocytic leukemia

The functional diversity of cells that compose myeloid malignancies, i.e., the respective roles of genetic and epigenetic heterogeneity in this diversity, remains poorly understood. This question is addressed in chronic myelomonocytic leukemia, a myeloid neoplasm in which clinical diversity contrasts with limited genetic heterogeneity. To generate induced pluripotent stem cell clones, we reprogrammed CD34⁺ cells collected from a patient with a chronic myelomonocytic leukemia in which whole exome sequencing of peripheral blood monocyte DNA had identified 12 gene mutations, including a mutation in KDM6A and two heterozygous mutations in TET2 in the founding clone and a secondary KRAS(G12D) mutation. CD34⁺ cells from an age-matched healthy donor were also reprogrammed. We captured a part of the genetic heterogeneity observed in the patient, i.e. we analyzed five clones with two genetic backgrounds, without and with the KRAS(G12D) mutation. Hematopoietic differentiation of these clones recapitulated the main features of the patient's disease, including overproduction of granulomonocytes and dysmegakaryopoiesis. These analyses also disclosed significant discrepancies in the behavior of hematopoietic cells derived from induced pluripotent stem cell clones with similar genetic background, correlating with limited epigenetic changes. These analyses suggest that, beyond the coding mutations, several levels of intraclonal heterogeneity may participate in the yet unexplained clinical heterogeneity of the disease.

High-frequency dynamics of evanescently-coupled nanowire lasers

We analyse the dynamics and conditions for stability in an array of two laterally-coupled nanowire lasers in terms of their separation, difference in resonant frequencies and pumping rate under conditions of weak coupling. We find that the regions of stability are very small and are found close to zero frequency offset between the lasers. Outside these regions various forms of instability including periodic oscillation, chaos and complex dynamics are predicted. Importantly, the analysis of the frequency of periodic oscillations for realistic laser separations and pumping yields values of order 100 GHz thus underlining the significant potential of nanowire laser arrays for ultra-high frequency on-chip systems with very low foot-print and energy requirements.

16S rRNA amplicon sequencing characterization of caecal microbiome composition of broilers and free-range slow-growing chickens throughout their productive lifespan

Gut microbiota affects health, metabolism and immunity of the host, and in the case of livestock, also food-safety. Here, 16S rRNA gene high-throughput Illumina sequencing was used to describe the microbiome of chicken caeca in two different breeds and management systems throughout their whole productive lifespan. Broilers (Ross-308), as a fast-growing breed reared in an intensive system for 42-days, and a slow-growing breed of chicken (Sasso-T451A) reared in an extensive farming system with outdoor access for 86-days, were compared. The core microbiome and differentially abundant taxa, as well as taxa associated with age were identified. Age was identified as the strongest influencing factor in caecal microbiota composition, and, in general, each age-group showed an age-associated community profile, with a transition period at the middle of their lifespan. However, substantial differences were observed in the composition of caecal microbiota of both chicken breeds, microbiota being richer and more complex in free-range chicken than in broilers. Several taxa positively/negatively correlated with Campylobacter relative abundance were also identified. Especially noteworthy was the identification by microbial community comparison of microbiota profiles suggestive of dysbiosis in several free-range chickens, probably associated to the typhlitis observed in the lumen of their caeca.

Zoonotic approach to Shiga toxin-producing Escherichia coli: integrated analysis of virulence and antimicrobial resistance in ruminants and humans

In 2014-2016, we conducted a cross-sectional survey in 115 sheep, 104 beef and 82 dairy cattle herds to estimate Shiga toxin-producing Escherichia coli (STEC) prevalence, and collected data on human clinical cases of infection. Isolates were characterised (stx1, stx2, eae, ehxA) and serogroups O157 and O111 identified by PCR, and their antimicrobial resistance (AMR) profiles were determined by broth microdilution. STEC were more frequently isolated from beef cattle herds (63.5%) and sheep flocks (56.5%) than from dairy cattle herds (30.5%) (P < 0.001). A similar but non-significant trend was observed for O157:H7 STEC. In humans, mean annual incidence rate was 1.7 cases/100 000 inhabitants for O157 STEC and 4.7 for non-O157 STEC, but cases concentrated among younger patients. Distribution of virulence genes in STEC strains from ruminants differed from those from human clinical cases. Thus, stx2 was significantly associated with animal STEC isolates (O157 and non-O157), ehxA to ruminant O157 STEC (P = 0.004) and eae to human non-O157 STEC isolates (P < 0.001). Resistance was detected in 21.9% of human and 5.2% of animal O157 STEC isolates, whereas all non-O157 isolates were fully susceptible. In conclusion, STEC were widespread in ruminants, but only some carried virulence genes associated with severe disease in humans; AMR in ruminants was low but profiles were similar to those found in human isolates.

Stable levels of Coxiella burnetii prevalence in dairy sheep flocks but changes in genotype distribution after a 10-year period in northern Spain

Bulk tank milk (BTM) samples were collected from 81 sheep flocks in the Basque Country, Spain, in 2015 and were analysed for antibodies against Coxiella burnetii by ELISA and for C. burnetii DNA by real-time PCR. Thirty-two percent of the flocks had BTM antibodies against C. burnetii. Presence of C. burnetii DNA in BTM was detected in 23% of the flocks, suggesting recent C. burnetii infections. Retrospective data of BTM samples obtained from 154 sheep flocks investigated in 2005 in the same geographic area were compiled to assess temporal changes in C. burnetii infection. The overall percentage of infected sheep flocks did not significantly change after the 10-year period. Among the 46 flocks sampled in both periods, 11 flocks that were negative in 2005 were positive in 2015, 18 maintained their initial status (positive or negative), and 17 positive flocks were negative in 2015. These findings indicate that C. burnetii infection is a dynamic process in dairy sheep in northern Spain. Single nucleotide polymorphism (SNP) genotyping of positive samples identified three genotypes, SNP1 being the most prevalent in 2015 and SNP8 in 2005; SNP4 was only detected once in 2005. These results suggest possible changes in the pattern of genotype infection over time.

Abstract P4-03-03: Not presented

This abstract was not presented at the symposium.

Short communication: Signs of host genetic regulation in the microbiome composition in 2 dairy breeds: Holstein and Brown Swiss

This study aimed to evaluate whether the host genotype exerts any genetic control on the microbiome composition of the rumen in cattle. Microbial DNA was extracted from 18 samples of ruminal content from 2 breeds (Holstein and Brown Swiss). Reads were processed using mothur (https://www.mothur.org/) in 16S and 18S rRNA gene-based analyses. Then, reads were classified at the genus clade, resulting in 3,579 operational taxonomic units (OTU) aligned against the 16S database and 184 OTU aligned against the 18S database. After filtering on relative abundance (>0.1%) and penetrance (95%), 25 OTU were selected for the analyses (17 bacteria, 1 archaea, and 7 ciliates). Association with the genetic background of the host animal based on the principal components of a genomic relationship matrix based on single nucleotide polymorphism markers was analyzed using Bayesian methods. Fifty percent of the bacteria and archaea genera were associated with the host genetic background, including Butyrivibrio, Prevotella, Paraprevotella, and Methanobrevibacter as main genera. Forty-three percent of the ciliates analyzed were also associated with the genetic background of the host. In total, 48% of microbes were associated with the host genetic background. The results in this study support the hypothesis and provide some evidence that there exists a host genetic component in cattle that can partially regulate the composition of the microbiome.

Effects of dry whey powder and calcium butyrate supplementation of corn/soybean-based diets on productive performance, duodenal histological integrity, and Campylobacter colonization in broilers

BACKGROUND

Campylobacter is the main cause of gastroenteritis in humans in industrialized countries, and poultry is its principal reservoir and source of human infections. Dietary supplementation of broiler feed with additives could improve productive performance and elicit health benefits that might reduce Campylobacter contamination during primary production. The aim of this study was to assess the effect of dietary supplementation with whey (a prebiotic) and calcium butyrate (a salt of a short-chain fatty acid) on productive traits, duodenal histological integrity, and Campylobacter colonization and dissemination in broiler chickens during the 42-day rearing period.

RESULTS

Six hundred one-day-old Ross-308 chickens were placed into 20 ground pens and assigned to one of 4 corn/soybean-based dietary treatments (5 replicates of 30 chicks per treatment) following a randomized complete block design: 1) basal diet with no supplementation as the control, 2) diet supplemented with 6% dry whey powder, 3) diet containing 0.1% coated calcium butyrate, and 4) diet containing 6% whey and 0.1% calcium butyrate. At age 15 days, 6 chickens per pen were experimentally inoculated with Campylobacter jejuni. The results showed that supplementation of the corn/soybean-based diet with 6% whey alone or, preferably, in combination with 0.1% coated calcium butyrate improved growth and feed efficiency, had a beneficial effect on duodenal villus integrity, and decreased mortality. These favourable effects were particularly significant during the starter period. Six days after oral challenge, Campylobacter was widespread in the flock, and the birds remained positive until the end of the rearing period. Although Campylobacter was not isolated from environmental samples, it was detected by real-time polymerase chain reaction (PCR) in dust, air filters, and drinkers while birds shed culturable C. jejuni cells. No differences (p > 0.050) in colonization or shedding levels that could be attributed to the diet were observed during the assay.

CONCLUSIONS

Beneficial effects on performance and intestinal health were observed, particularly during the starter period, when chickens were fed a diet supplemented with both whey and coated calcium butyrate. However, none of the tested diets provided the chicks any differential degree of protection against Campylobacter infection.

Nomogram-based prediction of survival in patients with advanced oesophagogastric adenocarcinoma receiving first-line chemotherapy: a multicenter prospective study in the era of trastuzumab

Background:

To develop and validate a nomogram and web-based calculator to predict overall survival (OS) in Caucasian-advanced oesophagogastric adenocarcinoma (AOA) patients undergoing first-line combination chemotherapy.

Methods:

Nine hundred twenty-four AOA patients treated at 28 Spanish teaching hospitals from January 2008 to September 2014 were used as derivation cohort. The result of an adjusted-Cox proportional hazards regression was represented as a nomogram and web-based calculator. The model was validated in 502 prospectively recruited patients treated between October 2014 and December 2016. Harrell's c-index was used to evaluate discrimination.

Results:

The nomogram includes seven predictors associated with OS: HER2-positive tumours treated with trastuzumab, Eastern Cooperative Oncology Group performance status, number of metastatic sites, bone metastases, ascites, histological grade, and neutrophil-to-lymphocyte ratio. Median OS was 5.8 (95% confidence interval (CI), 4.5–6.6), 9.4 (95% CI, 8.5–10.6), and 14 months (95% CI, 11.8–16) for high-, intermediate-, and low-risk groups, respectively (P<0.001), in the derivation set and 4.6 (95% CI, 3.3–8.1), 12.7 (95% CI, 11.3–14.3), and 18.3 months (95% CI, 14.6–24.2) for high-, intermediate-, and low-risk groups, respectively (P<0.001), in the validation set. The nomogram is well-calibrated and reveals acceptable discriminatory capacity, with optimism-corrected c-indices of 0.618 (95% CI, 0.591–0.631) and 0.673 (95% CI, 0.636–0.709) in derivation and validation groups, respectively. The AGAMENON nomogram outperformed the Royal Marsden Hospital (c-index=0.583; P=0.00046) and Japan Clinical Oncology Group prognostic indices (c-index=0.611; P=0.03351).

Conclusions:

We developed and validated a straightforward model to predict survival in Caucasian AOA patients initiating first-line polychemotherapy. This model can contribute to inform clinical decision-making and optimise clinical trial design.

High frequency continuous birefringence-induced oscillations in spin-polarized vertical-cavity surface-emitting lasers

Sustained, large amplitude and tunable birefringence-induced oscillations are obtained in a spin-vertical cavity surface-emitting laser (spin-VCSEL). Experimental evidence is provided using a spin-VCSEL operating at 1300 nm, under continuous-wave optical pumping and at room temperature. Numerical and stability analyses are performed to interpret the experiments and to identify the combined effects of pump ellipticity, spin relaxation rate, and cavity birefringence. Importantly, the frequency of the induced oscillations is determined by the device's birefringence rate, which can be tuned to very large values. This opens the path for ultrafast spin-lasers operating at record frequencies exceeding those possible in traditional semiconductor lasers and with ample expected impact in disparate disciplines (e.g., datacomms, spectroscopy).

Factors associated with poor outcomes in patients with lupus nephritis

The objective of this study was to identify the factors associated with important clinical outcomes in a case-control study of 213 patients with lupus nephritis. Included were 47% Hispanics, 44% African Americans and 9% Caucasians with a mean age of 28 years. Fifty-four (25%) patients reached the primary composite outcome of doubling serum creatinine, end-stage renal disease or death during a mean follow-up of 37 months. Thirty-four percent African Americans, 20% Hispanics and 10% Caucasians reached the primary composite outcome ( P < 0.05). Patients reaching the composite outcome had predominantly proliferative lupus nephritis (WHO classes: 30% III, 32% IV, 18% V and 5% II, P < 0.025) with higher activity index score (7 ± 6 versus 5 ± 5, P<0.05), chronicity index (CI) score (4 ± 3 versus 2 ± 2 unit, P<0.025), higher baseline mean arterial pressure (MAP) (111 ± 21 versus 102 ± 14 mmHg, P<0.025) and serum creatinine (1.9 ± 1.3 versus 1.3 ± 1.0 mg/dL, P<0.025), but lower baseline hematocrit (29 ± 6 versus 31 + 5%, P<0.025) and complement C3 (54 ± 26 versus 65 + 33 mg/dL, P<0.025) compared to controls. More patients reaching the composite outcome had nephrotic range proteinuria compared to controls (74% versus 56%, P<0.025). By multivariate analysis, CI (hazard ratio [95% CI] 1.18 [1.07-1.30] per point), MAP (HR 1.02 [1.00-1.03] per mmHg), and baseline serum creatinine (HR 1.26 [1.04-1.54] per mg/dL) were independently associated with the composite outcome. We concluded that hypertension and elevated serum creatinine at the time of the kidney biopsy as well as a high CI are associated with an increased the risk for chronic renal failure or death in patients with lupus nephritis.

Abstract P6-08-05: Protein tyrosine kinase activity and miRNA expression profiling reveals differences according to progesterone-receptor-status in HER-2 negative breast cancer

Background: Kinases are considered as promising source of biomarkers for diagnostic, prognostic and therapeutic purposes in cancer patients. We assessed tyrosine kinase activity in 39 primary breast cancer samples that were all hormone receptor positive (ER+ and/or PR+) with differential HER-2 status, using microarray technology. Methods: Pamchip® peptide microarrays were used to measure the activity of protein tyrosine kinases in 32 breast cancer samples. The breast cancer cell lines MCF-7, BT474 and ZR75-1, was studied for kinase activity, both untreated and treated with estradiol. Results: Results showed differences in phosphorylation amongst breast cancer samples. A total of 37 peptide kinases were highly phosphorylated in a group of breast cancer samples representing 33 protein tyrosine kinases involved in cancer pathways and immunological responses. In vitro studies with breast cancer cell lines exhibited the same phosphorylation profiles, but increased phosphorylation was only observed in one cell line, ZR75-1. Eliminating HER-2 positive samples, we obtained differences in phosphorylation profiles based on PR-status only. Samples lacking PR-expression exhibited higher kinase activity of downstream kinases compared to PR-positive samples. Similar results were obtained with miRNA expression profiles of 31 breast cancer samples. Five miRNAs were identified to be significantly differentially expressed (p &lt; 0.05) between PR-negative and PR-positive samples. This effect was even stronger when eliminating HER-2 positive samples, with 13 miRNAs exhibiting significant differential expression based on PR-status. Conclusion: Although our data are based on a small dataset, the lack of PR expression seems to have a profound effect on tyrosine kinase activity and miRNA expression in HER-2 negative breast cancers without any effect on gene expression. This indicates that regulatory and functional molecules might exhibit phenotypical features of cancer that cannot be explained by gene expression alone.

Citation Format: Tahiri A, Satheesh SV, de Wijn R, Lders T, Aure MR, Quigley DA, Bukholm IR, Hurtado A, Kristensen VN, Geisler J. Protein tyrosine kinase activity and miRNA expression profiling reveals differences according to progesterone-receptor-status in HER-2 negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-08-05.

Considering the uncertainties in empirical correlations for vertical countercurrent flow limitation (CCFL) with TRACE

TRACE is used to calculate the thermal-hydraulic sequence in nuclear power plants for accident analysis. In some postulated accidents, countercurrent flow limitation (CCFL) phenomena can occur. This phenomenon is calculated by means of empirical relationships in TRACE. Usually, not all empirical relationships used in TRACE are accessible to the user who develops the computational model for accident analysis, but in the case of CCFL, the user must specify the parameters of the empirical relationship. Additional preliminary work is needed for fitting the parameters so that experimental data matches the computational calculations and the accident analysis can be performed. Furthermore, uncertainties in measurement errors from experimental data lead to user-based variations in the parameters of the empirical relationship for CCFL. Therefore, an alternative procedure in which accident analysis is performed with consideration of the uncertainties in the empirical relationships is presented. The uncertainty was quantified by means of a stochastic linear regression model for the Wallis correlation and the Bankoff correlation. An uncertainty analysis was subsequently performed to demonstrate the influence of uncertainty in certain cases of CCFL.

Arrest of Domain Coarsening via Antiperiodic Regimes in Delay Systems

Motionless domain walls representing connecting temporal or spatial orbits typically exist only for very specific parameters, around the so-called Maxwell point. This report introduces a novel mechanism for stabilizing temporal domain walls away from this peculiar equilibrium, opening up new possibilities to encode information in dynamical systems. It is based on antiperiodic regimes in a delayed system close to a bistable situation, leading to a cancellation of the average drift velocity. The results are demonstrated in a normal form model and experimentally in a laser with optical injection and delayed feedback.

Q Fever Outbreak among Workers at a Waste-Sorting Plant

An outbreak of Q fever occurred in February-April 2014 among workers at a waste-sorting plant in Bilbao (Spain). The outbreak affected 58.5% of investigated employees, 47.2% as confirmed cases (PCR and/or serology) and 11.3% as probable cases (symptoms without laboratory confirmation). Only employees who had no-access to the waste processing areas of the plant were not affected and incidence of infection was significantly higher among workers not using respiratory protection masks. Detection by qPCR of Coxiella burnetii in dust collected from surfaces of the plant facilities confirmed exposure of workers inside the plant. Animal remains sporadically detected among the residues received for waste-sorting were the most probable source of infection. After cleaning and disinfection, all environmental samples tested negative. Personal protection measures were reinforced and made compulsory for the staff and actions were taken to raise farmers' awareness of the biological risk of discharging animal carcasses as urban waste.

Genetic diversity and variation over time of Coxiella burnetii genotypes in dairy cattle and the farm environment

The genetic diversity of Coxiella burnetii from 36 dairy cattle herds was determined by Multiple-Locus Variable number tandem repeats Analysis (MLVA), and genotypes from different sources (bulk-tank milk - BTM and surface dust) and sampling time (2009/10 and 2011/12) were compared. A total of 15 different genotypes were identified from 60 BTM and seven dust samples, including seven genotypes reported here for the first time (BN, BO, BP, BQ, BR, BS, BT). The two most prevalent genotypes (J and I), detected both in BTM and dust, accounted for 44.5% of the C. burnetii typed and have been reported infecting cattle worldwide. In 52% of herds more than one genotype was found, and mixed infection with two genotypes was observed in seven BTM samples. Comparison of C. burnetii genotypes at different samplings within each herd detected a change in genotype in 32% of herds, while a persistent genotype was identified in the remaining 68%. In addition, the genotype obtained from dust samples was always identical to that present in the BTM sample. Often persistent genotypes were among the most prevalent types. Clustering of the MLVA genotypes from this and other studies using the minimum spanning tree method separated our C. burnetii strains into two clusters, 10 genotypes clustered within genomic group (GG) III, and the remaining five types (AE, BQ, BR, BS and BT) grouped with GG II, which includes strains implicated in human outbreaks. Although presence in cattle of genotypes closely related to those identified in humans does not seem to be common event, it cannot be neglected and surveillance of genotype distribution is needed to fully understand the epidemiology of Q fever.

Reverse line blot hybridization with species-specific oligonucleotide probes: application to piroplasm detection

Reverse line blot (RLB) hybridization has become a well-established and widely used method for the multiplex identification of several Babesia and Theileria species in hosts and tick vectors. The procedure is based on the simultaneous PCR amplification of a polymorphic region of the 18S rRNA gene from different piroplasms followed by identification of the individual species by hybridization to species-specific oligonucleotide probes covalently linked to a nylon membrane in a macroarray format.

Risks of suffering tick-borne diseases in sheep translocated to a tick infested area: a laboratory approach for the investigation of an outbreak

This study was designed to investigate an outbreak of high mortality that occurred in naïve Assaf sheep introduced into a Latxa sheep flock in the Basque Country, a region where piroplasmosis is endemic. To identify the causes of this outbreak, a panel of different methods, including traditional pathological, biopathological and parasitological analyses combined with recently developed molecular methods, was used. These novel molecular methods included a multiplex real-time PCR assay to screen for the presence of the most important tick-borne pathogens (piroplasms and anaplasmas), followed by a second species-specific multiplex real-time PCR assay for the identification of Anaplasma-positive samples. The identification of piroplasm-positive samples was carried out by a multiplexed microsphere-based suspension array using a Luminex(®) xMAP technology-based procedure. Anaplasmas and/or piroplasms were detected in 7/10 lambs and 11/13 ewes, with Babesia ovis being detected in 12 of the 23 animals, Theileria ovis in 6 and Anaplasma ovis in 4, both as single and mixed infections. Most of the animals infected with B. ovis had a marked decrease in the values of the red blood cell parameters. Ticks collected from the animals were identified as Riphicephalus bursa, recognised vector of B. ovis. Other haemolytic pathologies (clostridial disease, copper poisoning and leptospirosis) were ruled out and, considering all clinical, laboratory and epidemiological data, babesiosis by B. ovis was diagnosed. A detailed description of the clinical outcome, with ca. 60% of mortality, laboratory results and epidemiological findings are provided. The implications of the introduction of naïve animals into a piroplasmosis endemic area are discussed.

Progression of Coxiella burnetii infection after implementing a two-year vaccination program in a naturally infected dairy cattle herd

Background

The high prevalence of Coxiella burnetii infection in dairy cattle herds recently reported and the long survival time of the bacterium in the environment pose a risk to human and animal health that calls for the implementation of control measures at herd level. This study presents the results of a 2-year vaccination program with an inactivated phase I vaccine in a Spanish dairy herd naturally infected with C. burnetii. Calves older than 3 months and non-pregnant heifers and cows were vaccinated in April 2011 and the farm was subsequently visited at a monthly basis for vaccination of recently calved cows and calves that reached the age of 3 months. Annual booster doses were given to previous vaccinated animals as well. The effectiveness of the vaccine was assessed in terms of level of C. burnetii shedding through milk and uterine fluids and environmental contamination as determined by polymerase chain reaction (PCR).

Results

The percentage of shedder animals through uterine fluids and milk progressively decreased, and C. burnetii DNA load in bulk-tank milk samples was low at the end of the study. The average seroconversion rate in not yet vaccinated animals, which acted as control group, was 8.6% during the first year and 0% in the second year. DNA of C. burnetii was found in aerosols and dust samples taken in the calving area only at the beginning of the study, whereas slurry samples remained C. burnetii PCR positive for at least 18 months. Multiple Locus Variable number tandem-repeat Analysis identified the same genotype in all C. burnetii DNA positive samples.

Conclusions

In the absence of any changes in biosecurity, the overall reduction of C. burnetii infection in animals to 1.2% milk shedders and the reduced environment contamination found at the end of the study was ascribed to the effects of vaccination together with the culling of milk shedders. Vaccination has to be planned as a medium-long term strategy to suppress risks of re-infection.