Characterization of cutaneous lesions caused by natural tick infestation in cattle.

Although tick infestation is a significant health problem in livestock, there are limited studies on the dermatopathological aspects of natural tick infestation in cattle. This study aimed to describe the gross and histologic aspects of cutaneous lesions caused by tick infestation in cattle. Thirteen cases were selected based on necropsy data from a 10-year retrospective study. Predispositions were observed in beef cattle (P = .049) and the Angus breed (P = .012), and lesions occurred mainly in the fall (P = .007). Gross lesions included hypotrichosis (13/13; 100%), scales (12/13; 92%), alopecia (11/13; 85%), ulcers (7/13; 54%), crusts (7/13; 54%), and erosions (2/13; 15%). These gross lesions were mainly located in the thorax (12/13; 92%), head (11/13; 85%), abdomen (10/13; 77%), neck (9/13; 69%), limbs (9/13; 69%), and perineum (9/13; 69%). Histologically, all cases had ticks adhered to the epidermis with erosions (13/13; 100%), ulcers (11/13; 85%), orthokeratotic hyperkeratosis (13/13; 100%), irregular acanthosis (13/13; 100%), intraepidermal pustules (13/13; 100%), crusts (10/13; 77%), and ballooning degeneration (4/13; 31%). In the dermis, just below the tick insertion site, there was coagulation necrosis, fibrin deposition, and inflammatory infiltrate composed of mixed cells (neutrophils, lymphocytes, plasma cells, macrophages, and few eosinophils) (9/13; 69%), neutrophils (3/13; 23%), or eosinophils (1/13; 8%). This study reinforces the different patterns of cutaneous lesions caused by tick infestation in cattle, which should be considered as a potential cause of dermatitis in this species.

α-Clustering in atomic nuclei from first principles with statistical learning and the Hoyle state character.

A long-standing crucial question with atomic nuclei is whether or not α clustering occurs there. An α particle (helium-4 nucleus) comprises two protons and two neutrons, and may be the building block of some nuclei. This is a very beautiful and fascinating idea, and is indeed plausible because the α particle is particularly stable with a large binding energy. However, direct experimental evidence has never been provided. Here, we show whether and how α(-like) objects emerge in atomic nuclei, by means of state-of-the-art quantum many-body simulations formulated from first principles, utilizing supercomputers including K/Fugaku. The obtained physical quantities exhibit agreement with experimental data. The appearance and variation of the α clustering are shown by utilizing density profiles for the nuclei beryllium-8, -10 and carbon-12. With additional insight by statistical learning, an unexpected crossover picture is presented for the Hoyle state, a critical gateway to the birth of life.

Clinical-epidemiological, anatomic-pathological, histochemical and immunohistochemical characterization of renal cystadenocarcinoma-nodular dermatofibrosis syndrome in 11 German Shepherd dogs / Caracterização clínico-epidemiológica, anátomo-patológica, histoquímica e imuno-histoquímica da síndrome cistadenocarcinoma-dermatofibrose nodular em 11 cães Pastor Alemão

Eleven cases of renal cystadenoma/cystadenocarcinoma-nodular dermatofibrosis syndrome (RCND) are described in German Shepherd dogs diagnosed from January 1994 to January 2018 at the Veterinary Pathology Laboratory of the "Universidade Federal de Santa Maria" (LPV-UFSM). The study sample was composed of eight male and three female dogs at a ratio of 2.67:1. Age ranged from six to 12 years (mean=8.7 years). The main clinical signs reported in descending order of frequency were multiple cutaneous nodules (nodular dermatofibrosis), dyspnea, anorexia, weight loss, recurrent hematuria, vomiting, and polydipsia. Results demonstrated that it is not always easy to clinically recognize this syndrome, but its peculiar anatomical-pathological characteristics allow safe diagnosis. Histologically, it was possible to detect all phases (cysts, papillary intratubular hyperplasia, and cystadenomas or cystadenocarcinomas) of a possible pathological continuum of the renal lesions. Uterine leiomyomas were observed in only one of the cases. Through histochemical techniques, it was possible to identify the presence of type I collagen in both cutaneous and renal lesions and consider its possible involvement in the pathogenesis of renal cystadenocarcinoma. Immunohistochemistry (IHC) showed partially satisfactory results in the staining of epithelial cells of renal cysts and neoplasms for pan-cytokeratin.(AU)

São descritos 11 casos da síndrome cistadenoma/cistadenocarcinoma-dermatofibrose nodular (CR-DN) em cães Pastor Alemão, diagnosticados entre janeiro de 1994 e janeiro de 2018 no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria (LPV-UFSM). Os cães afetados foram oito machos e três fêmeas, estabelecendo-se uma relação de 2,67:1. A idade variou de seis a 12 anos, sendo a média de idade de 8,7 anos. Os principais sinais clínicos relatados foram, em ordem decrescente de frequência, múltiplos nódulos cutâneos (dermatofibrose nodular), dispneia, anorexia, emagrecimento, hematúria recorrente, vômito e polidipsia. Este estudo permitiu estabelecer que o reconhecimento clínico da síndrome nem sempre é fácil, porém suas características anátomo-patológicas peculiares permitem um diagnóstico com segurança. Histologicamente, foi possível detectar todas as fases (cistos, hiperplasia intratubular papilífera, cistadenomas ou cistadenocarcinomas) de um possível continuum patológico das lesões renais. Leiomiomas uterinos foram observados somente em um caso. Através das técnicas histoquímicas foi possível estabelecer que o colágeno tipo I está presente em ambas as lesões, cutâneas e renais, e cogitar seu possível envolvimento na patogênese dos cistadenocarcinomas renais. A técnica de IHQ mostrou resultados parcialmente satisfatórios na imunomarcação das células epiteliais dos cistos e dos neoplasmas renais para pancitoceratina.(AU)

Monotropic polymorphism in a glass-forming metallic alloy.

This study investigates the crystallization and phase transition behavior of the amorphous metallic alloy Au70Cu5.5Ag7.5Si17. This alloy has been recently shown to exhibit a transition of a metastable to a more stable crystalline state, occurring via metastable melting under strong non-equilibrium conditions. Such behavior had so far not been observed in other metallic alloys. In this investigation fast differential scanning calorimetry (FDSC) is used to explore crystallization and the solid-liquid-solid transition upon linear heating and during isothermal annealing, as a function of the conditions under which the metastable phase is formed. It is shown that the occurrence of the solid-liquid-solid transformation in FDSC depends on the initial conditions; this is explained by a history-dependent nucleation of the stable crystalline phase. The microstructure was investigated by scanning and transmission electron microscopy and x-ray diffraction. Chemical mapping was performed by energy dispersive x-ray spectrometry. The relationship between the microstructure and the phase transitions observed in FSDC is discussed with respect to the possible kinetic paths of the solid-liquid-solid transition, which is a typical phenomenon in monotropic polymorphism.

Reduced susceptibilities to biocides and resistance to antibiotics in food-associated bacteria following exposure to quaternary ammonium compounds.

AIMS: Our aim was to assess the effects of step-wise exposure to didecyl dimethyl ammonium chloride (DDAC) on the antimicrobial (antibiotics and biocides) susceptibilities of food-associated bacterial strains. METHODS AND RESULTS: Adaptive responses of bacterial strains were investigated by exposing the strains daily to increasing subinhibitory concentrations of DDAC for 7 days. Following adaptation to DDAC, a threefold increase in the minimum inhibitory concentration (MIC) values for this biocide was observed in 48% of the Escherichia coli and Listeria monocytogenes strains, and 3% of the Salmonella strains. Reduced susceptibility to other biocides was found with the most important increase in MIC for benzalkonium chloride (BC) and a commercial biocide formulation (Galox Horizon) containing DDAC and glutaraldehyde, for all species except Salmonella. Increase in antibiotic MIC values was more pronounced in E. coli in terms of antibiotic numbers and of magnitude (from 4- to 32-fold increase) and, to a lesser extent, in Salmonella strains. Most of these strains had acquired resistance to ampicillin, cefotaxime, ceftazidime, chloramphenicol and ciprofloxacin. CONCLUSIONS: The effects of exposure to DDAC on biocides and antibiotics susceptibilities depend upon the bacteria species. SIGNIFICANCE AND IMPACT OF THE STUDY: Extensive use of DDAC at subinhibitory concentrations may lead to the development of antibiotic-resistant bacteria and may represent a public health issue.

Características clínico-epidemiológicas, histomorfológicas e histoquímicas da esporotricose felina / Clinical, epidemiological, histomorphological and histochemical characteristics of the feline sporotrichosis

Esporotricose é uma infecção fúngica causada por espécies do complexo Sporothrix, vista com maior frequência em gatos, equinos e cães. Os principais objetivos deste estudo retrospectivo foram caracterizar os aspectos histomorfológicos e histoquímicos da esporotricose em 10 gatos, além de avaliar os aspectos epidemiológicos, clínicos e os achados macroscópicos desses 10 casos, obtidos dos protocolos de biópsias e necropsias dos arquivos do Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria. A doença acometeu predominantemente gatos machos, sem raça definida e apresentou-se principalmente na forma cutânea disseminada...

Sporotrichosis is a mycotic infection caused by the Sporothrix complex species, affecting mostly cats, horses, and dogs. The main objectives of this retrospective study were to characterize the histomorphological and histochemical aspects of sporotrichosis in 10 cats, and also to evaluate epidemiological and clinical aspects, and gross findings obtained from the biopsy and necropsy protocols of these ten cases, obtained from the archives of the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria. The disease affected mostly male mongrel cats, and was mostly observed in the cutaneous disseminated form...

HDAC7 inhibition resets STAT3 tumorigenic activity in human glioblastoma independently of EGFR and PTEN: new opportunities for selected targeted therapies.

To date, the mutational status of EGFR and PTEN has been shown as relevant for favoring pro- or anti-tumor functions of STAT3 in human glioblastoma multiforme (GBM). We have screened genomic data from 154 patients and have identified a strong positive correlation between STAT3 and HDAC7 expression. In the current work we show the existence of a subpopulation of patients overexpressing HDAC7 and STAT3 that has particularly poor clinical outcome. Surprisingly, the somatic mutation rate of both STAT3 and HDAC7 was insignificant in GBM comparing with EGFR, PTEN or TP53. Depletion of HDAC7 in a range of GBM cells induced the expression of tyrosine kinase JAK1 and the tumor suppressor AKAP12. Both proteins synergistically sustained the activity of STAT3 by inducing its phosphorylation (JAK1) and protein expression (AKAP12). In absence of HDAC7, activated STAT3 was responsible for significant imbalance of secreted pro-/anti-angiogenic factors. This inhibited the migration and sprouting of endothelial cells in paracrine fashion in vitro as well as angiogenesis in vivo. In a murine model of GBM, induced HDAC7-silencing decreased the tumor burden by threefold. The current data show for the first time that silencing HDAC7 can reset the tumor suppressor activity of STAT3, independently of the EGFR/PTEN/TP53 background of the GBM. This effect could be exploited to overcome tumor heterogeneity and provide a new rationale behind the development of specific HDAC7 inhibitors for clinical use.

Comparison of the virucidal efficacy of peracetic acid, potassium monopersulphate and sodium hypochlorite on bacteriophages P001 and MS2.

AIMS: The phagicidal activity of peroxy products against the virulent bacteriophage P001 infecting lactic acid bacteria and bacteriophage MS2 used as a surrogate of enteric viruses (EVs) was evaluated and compared to sodium hypochlorite using the EN 13610 European suspension test and a surface test developed in our laboratories. METHODS AND RESULTS: Infectivity tests were adapted and/or developed to determine the activity of disinfectants against reference P001 phage of Lactoccocus lactis and F-specific RNA phage MS2 of Escherichia coli in conditions simulating practical use. Similar concentrations of sodium hypochlorite were phagicidal against both bacteriophages, either at 0·05-0·125% of active chlorine using the suspension test or at 0·12-0·5% using the surface test. For Potassium monopersulphate (MPS), phagicidal concentrations varied from 0·006 to 0·012% whatever the type of test and phages. However, for peracetic acid products (PAP) used in suspension, concentrations 55 times higher were necessary against MS2 (0·271%) than against P001 (0·005%). With the surface test, 0·089-0·178% concentrations of PAP were effective against MS2, but these concentrations were 16-32 times greater than needed against P001. CONCLUSIONS: Sodium hypochlorite and MPS had similar phagicidal activities against P001 and MS2, but PAP did not. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first comparative study to investigate through suspension and surface tests the difference in resistance to peroxy compounds between a reference bacteriophage (P001) used to evaluate phagicidal concentrations in European standards and a surrogate of EVs (MS2). Results underline the importance of validation tests on pertinent surrogates of viruses or bacteriophages to adjust the concentration of disinfectants for use in the food and water industries.

Comparison of the virucidal efficiency of peracetic acid, potassium monopersulfate and sodium hypochlorite on hepatitis A and enteric cytopathogenic bovine orphan virus.

AIMS: The virucidal activity of peroxy-products was evaluated and compared with sodium hypochlorite using the EN 14675 European suspension test and a surface test developed in our laboratory. The classical approach on infectivity of viruses was complemented with a prospective approach on virus genomes. METHODS AND RESULTS: Both infectivity tests were adapted and/or developed to determine the activity of disinfectants against reference bovine enterovirus type 1 [enteric cytopathogenic bovine orphan virus (ECBO)] and resistant hepatitis A virus (HAV) in conditions simulating practical use. Similar concentrations of active chlorine were virucidal against both viruses, either at 0·062% using the suspension test or at 0·50-1% using the surface test. However, for potassium monopersulfate and peracetic acid products, concentrations of approximately three times (3%) to 72 times (9%) higher were necessary against HAV than ECBO when determined with the suspension test. With the surface test, 4-8% peroxy-products were virucidal against HAV, either 16 times more peroxy-products concentrations than against ECBO. No significant impact on the targeted area of the viral genome measured by real-time RT-PCRs was obtained for ECBO and HAV suspensions treated with disinfectants, even with doses higher than the minimal virucidal concentrations. CONCLUSIONS: Sodium hypochlorite, but not peroxy-products, had similar activity against ECBO and HAV. No relation could be established between infectivity tests and genome destruction. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first comparative study that investigates with novel suspension and surface tests the reduction of infectivity and genome destruction of two resistant viruses by peroxy-compounds. The results and conclusions collected with European standards are discussed.

DAX-1, as an androgen-target gene, inhibits aromatase expression: a novel mechanism blocking estrogen-dependent breast cancer cell proliferation.

Sexual hormones, estrogens and androgens, determine biological response in a tissue- and gender-specific manner and have a pivotal role in endocrine-mediated tumorigenesis. In situ estrogen production by aromatase is a critical determinant for breast cancer growth and progression. On the contrary, clinical and in vitro studies indicate that androgens have a protective role in mammary carcinogenesis. Here, we demonstrated, in hormone-dependent breast cancer cells, the existence of a functional interplay between the androgen receptor (AR), the orphan nuclear receptor DAX-1 and the aromatase enzyme involved in the inhibition of the estrogen-dependent breast cancer cell proliferation exerted by androgen signaling. Indeed, our results revealed, in MCF-7 cells, that ligand-activated AR induces the expression of the orphan nuclear receptor DAX-1 by direct binding to a newly identified androgen-response-element within the DAX-1 proximal promoter. In turn, androgen-induced DAX-1 is recruited, in association with the corepressor N-CoR, within the SF-1/LRH-1 containing region of the aromatase promoter, thereby repressing aromatase expression and activity. In elucidating a novel mechanism by which androgens, through DAX-1, inhibit aromatase expression in breast cancer cell lines, these findings reinforce the theory of androgen- opposing estrogen-action, opening new avenues for therapeutic intervention in estrogen-dependent breast tumors.

Collective modes in light nuclei from first principles.

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.

Synergism between hydrogen peroxide and seventeen acids against five agri-food-borne fungi and one yeast strain.

AIMS: The objective of this study was to evaluate fungicidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. METHODS AND RESULTS: The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains (one yeast and five fungi) were reference strains and strains representative of contaminating fungi found in the food industry. Each synergistic hydrogen peroxide/acid combination found after fifteen minutes contact time at 20 °C in distilled water was then tested in conditions simulating four different use conditions. Twelve combinations were synergistic in distilled water, eleven of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination remained effective against four strains and was never antagonistic against the other two fungi. Combinations with propionic acid and acetic acid stayed synergistic against two strains. Those with oxalic acid and lactic acid kept their synergism only against Candida albicans. No synergism was detected against Penicillium cyclopium. CONCLUSIONS: Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. SIGNIFICANCE AND IMPACT OF THE STUDY: A rapid screening method developed in our laboratory for bacteria was adapted to fungi and used to reveal the synergistic potential of disinfectants and/or sanitizers combinations.

Synergism between hydrogen peroxide and seventeen acids against six bacterial strains.

AIMS: The objective of this study was to evaluate the bactericidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. METHODS AND RESULTS: The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains were reference strains and strains representative of contaminating bacteria in the food industry. Each synergistic hydrogen peroxide/acid combination found after 5-min contact time at 20°C in distilled water was then tested in conditions simulating four different use conditions. Thirty-two combinations were synergistic in distilled water; twenty-five of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination was synergistic for all six bacterial strains in distilled water and remained synergistic with interfering substances. Six other combinations maintained their synergistic effect in the presence of an organic load but only for one or two bacterial strains. CONCLUSIONS: Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. SIGNIFICANCE AND IMPACT OF THE STUDY: A rapid screening method was proposed and used to reveal the synergistic potential of disinfectant and/or sanitizer combinations.

Resistance to phenicol compounds following adaptation to quaternary ammonium compounds in Escherichia coli.

Bacterial adaptation to quaternary ammonium compounds (QACs) is mainly documented for benzalkonium chloride (BC) and few data are available for other QACs. The aim of this study was to assess the effects of repeated exposure to different quaternary ammonium compounds (QACs) on the susceptibility and/or resistance of bacteria to other QACs and antibiotics. Escherichia coli strains (n=10) were adapted by daily exposure to increasingly sub-inhibitory concentrations of a QAC for 7 days. Three QACs were studied. Following adaptation, we found similar levels of reduction in susceptibility to QACs with a mean 3-fold increase in the minimum inhibitory concentration (MIC) compared to initial MIC values, whatever the QAC used during adaptation. No significant differences in antibiotic susceptibility were observed between the tested QACs. Antibiotic susceptibility was reduced from 3.5- to 7.5-fold for phenicol compounds, ß lactams, and quinolones. Increased MIC was associated with a shift in phenotype from susceptible to resistant for phenicol compounds (florfenicol and chloramphenicol) in 90% of E. coli strains. Regardless of the QAC used for adaptation, exposure to gradually increasing concentrations of this type of disinfectant results in reduced susceptibility to QACs and antibiotics as well as cross-resistance to phenicol compounds in E. coli strains. Extensive use of QACs at sub-inhibitory concentrations may lead to the emergence of antibiotic-resistant bacteria and may represent a public health risk.

Origin of the anomalous long lifetime of ¹4C.

We report the microscopic origins of the anomalously suppressed beta decay of ¹4C to ¹4N using the ab initio no-core shell model with the Hamiltonian from the chiral effective field theory including three-nucleon force terms. The three-nucleon force induces unexpectedly large cancellations within the p shell between contributions to beta decay, which reduce the traditionally large contributions from the nucleon-nucleon interactions by an order of magnitude, leading to the long lifetime of ¹4C.

Electron in a transverse harmonic cavity.

Recent experiments with heavy ions and planned experiments with ultraintense lasers require nonperturbative solutions to quantum field theory for predicting and interpreting the results. To propel this theoretical direction, we solve the nonperturbative problem of an electron in a strong transverse confining potential using Hamiltonian light-front quantum field theory. We evaluate both the invariant mass spectra and the anomalous magnetic moment of the lowest state for this two-scale system. The weak external field limit of the anomalous magnetic moment agrees with the result of QED perturbation theory within the anticipated accuracy.

Recovery of Campylobacter jejuni from surfaces of poultry slaughterhouses after cleaning and disinfection procedures: analysis of a potential source of carcass contamination.

Campylobacters are a primary cause of human bacterial enteritis worldwide. They are usually considered susceptible to the disinfectant molecules used in the food industry. The purpose of this study was to see if campylobacters could survive cleaning and disinfection in poultry slaughterhouses and whether the strains recovered could contaminate carcasses during processing. Samples obtained from the environment before and after cleaning and disinfection (transport crates, processing equipment surfaces, scald tank water) and from birds (fresh droppings, neck skins) were collected during 7 investigations in 4 different slaughterhouses. Out of 41 samples collected, 30 Campylobacter jejuni strains were recovered from the surfaces of processing equipment before cleaning and disinfection procedures in three slaughterhouses and 9 C. jejuni out of 51 samples collected were found after cleaning. The study was then focused on one slaughterhouse to trace passage of the pathogen on poultry carcasses. The antimicrobial resistance phenotypes (P) (minimum inhibitory concentration, MIC) of the C. jejuni isolates collected in this slaughterhouse were determined. Nine phenotypes could be distinguished. Three of these were of interest as they were found in isolates recovered after cleaning and disinfection procedures. The genotypes (G) were determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) of isolates with one of the three phenotypes of interest. Clusters constructed by combining the phenotype and genotyping observations (PG type) were compared between isolates obtained after cleaning and disinfection, and isolates from droppings, neck skin and transport crate samples of slaughtered poultry flocks. Only one PG type of strain was recovered from surfaces after cleaning and disinfection and from neck skin samples but was also recovered from transport crates. Our findings indicate that C. jejuni is able to survive overnight on food processing equipment surfaces, after cleaning and disinfection procedures, and that these strains may contaminate carcasses during the slaughter process. These results add to our understanding of poultry carcass contamination and highlight the need to develop ways of reducing the risk of human infection with Campylobacter through the consumption of poultry products.

[Solitary albinotic spot of the retinal pigment epithelium: a functional and imaging study]. / Solitärer, albinotischer "Fleck" des retinalen Pigmentepithels: klinische und funktionelle Befunde.

PURPOSE: The presence or absence of functional changes associated with solitary, congenital, hypopigmented lesions of the retinal pigment epithelium (RPE) have been a matter of controversy. This case report describes retinal and functional findings in a young patient with such a lesion. METHODS: A 10-year-old Hispanic female with a solitary congential hypopigmented spot of the RPE was examined using fundus photography, fluorescein angiography, autofluorescence imaging (AF) and optical coherence tomography (OCT). Functional analyses were performed using the Humphrey 24 - 2 visual field, Goldmann perimetry and the multifocal ERG (mfERG). RESULTS: A small visual field defect was demonstrated on both Goldmann perimetry (I/ 2e test object) and on Humphrey 24 - 2 visual field testing (significant at the 0.5 % level for pattern deviation). The multifocal ERG response amplitudes were decreased in the corresponding area and increased in implicit time. Autofluorescence imaging showed an absence of fluorescence corresponding to the area of the lesion. OCT findings were indicative of a small amount of subretinal fluid or schisis-like changes overlying the RPE anomaly. CONCLUSION: The results indicate that solitary, albinotic spots of the RPE can be associated with visual field defects and outer retinal deficits; these may be related to impaired RPE function and/or chronic exudative changes.

Phenotypes and genotypes of campylobacter strains isolated after cleaning and disinfection in poultry slaughterhouses.

Campylobacter is responsible for human bacterial enteritis and poultry meat is recognised as a primary source of infection. In slaughterhouses, cleaning and disinfection procedures are performed daily, and it has been suggested that disinfectant molecules might select for antibiotic resistant strains if shared targets or combined resistance mechanisms were involved. The aim of the study was to investigate if cleaning and disinfection procedures in poultry slaughterhouses select for antibiotic resistance in Campylobacter jejuni and C. coli and to determine the genotypes of isolates collected after cleaning and disinfection. Nine sampling visits were made to four French slaughterhouses. Samples were collected from transport crates and equipment surfaces, before and after cleaning and disinfection. Minimal inhibitory concentrations of the recovered C. jejuni and C. coli isolates to six antibiotics and two disinfectants were measured. The C. jejuni isolates collected from equipment surfaces after cleaning and disinfection were subjected to PCR-RFLP typing. Twenty-five C. jejuni isolates and 1 C. coli were recovered from equipment surfaces after cleaning and disinfection during five visits to three different slaughterhouses. Those isolates did not show an increased resistance to the tested antibiotics compared to isolates collected before cleaning and disinfection. Only one or two genotypes were recovered after cleaning and disinfection during single visits to each slaughterhouse. This observation suggests that such genotypes may be particularly adapted to survive cleaning and disinfection stress. Understanding the survival mechanisms of Campylobacter should facilitate the implementation of better-targeted strategies and reduce the public health burden associated with Campylobacter infection.