Occurrence and genetic diversity of Salmonella in organic and conventional pig productions in France

The objectives of this study were 1) to assess the occurrence of Salmonella in organic pig production, in comparison with conventional pig production, 2) to evaluate the genetic diversity of strains isolated from these two productions and 3) to estimate the cross-contamination on slaughter line between conventional pig and organic pig. In one slaughterhouse, 26 organic herds and 31 conventional herds (2 pigs per herd) were sampled for Salmonella detection. Analyses were realized on colon content and swabs of carcass for each pig. Two isolates by positive samples were serotyped and typed by PFGE using XbaI enzyme. All S. Typhimurim and monophasic variant of serovar Typhimurium were subtyped by MLVA. Prevalence of Salmonella in colon content was higher for organic pigs, 37.9% IC95than for conventional pigs, 32.7% but difference was not significant (p=0.563). Salmonella prevalence was lowest on carcasses and very close between the two productions: 10.7% for organic and 10.3% for conventional. The 104 isolates were distributed in 7 serovars: Derby (46 isolates), Brandenburg (18), Typhimurium (13), monophasic variant of Typhimurium 4,12:i:- (11) and 4,5,12:i:- (10), Infantis (2) and Mbandaka (2). Sixteen PFGE profiles were obtained: 1 per serovar for serovars Mbandaka, Infantis, and Brandenbrug, 3 for Derby, 4 for Typhimurium and 4 for monophasic variant 4,12:i:-. Seven PFGE profiles, representing 84% of the isolates, were common between organic and conventional pigs. A major profile gathered 79% of the S. Derby strains. S. Brandenburg strains were also very clonal, all presented the same PFGE profiles whereas they came from 5 different herds. With 20 isolates from 12 carcasses, it has not been possible to show with certainty Salmonella cross-contamination between organic and conventional pigs during the process. For S. Typhimurium, MLVA gave a better discrimination than PFGE, 8 patterns against 4; particularly for 6 isolates with the same PFGE pattern which was subdivided into 5 MLVA patterns. While on the 21 monophasic isolates, MLVA and PFGE gave similar discrimination (7 patterns with MLVA and 6 with PFGE)

Prevalence and genetic diversity of Salmonella in organic and conventional pig productions in France

The objectives of this study were 1) to assess the occurrence of Salmonella in organic and conventional pig productions, 2) to evaluate the genetic diversity of strains isolated from these two productions, and 3) to estimate the cross-contamination on slaughter line between conventional pigs and organic pigs. 26 organic herds and 31 conventional herds were considered in one slaughterhouse. Two pigs per herds were sampled. For each pig, Salmonella detection was realized on colon content and swabs of carcass. Two isolates per positive samples were serotyped and genotyped by PFGE using XbaI enzyme. Prevalence of Salmonella in colon content was higher for organic pigs, 37,9% IC95%[25.5-51.6] than for conventional pigs, 32.7% IC95%[19.5-44.5] but it was not significantly different. Salmonella prevalence was lowest on carcasses and very close between the two productions; 10.7% IC95%[4.0-21.8] for organic carcasses and 10.3 IC95%[3.9-21.2]) for conventional carcasses. The 104 isolates were distributed in 7 serovars: Derby (46), , Brandenburg (18), Typhimurium (13), 2 types of monophasic variant of serovar Typhimurium 4,12:i:- (11) and 4,5,12:i:- (10), Infantis (2) and Mbandaka (2). Sixteen PFGE profiles were obtained: 1 per serovar for Mbandaka, Infantis, and Brandenbrug, 2 for monophasic variant 4,5,12:i:-, 3 for Derby, 4 for Typhimurium and 4 for monophasic variant 4,12:i:-. Seven PFGE profiles (84% of the strains) were common between organic and conventional pigs. A major profile gathered 79% of the S. Derby strains. S. Brandenburg strains presented only one PFGE profile which was detected in 5 different herds. It has not been possible to show with certainty Salmonella cross-contamination between organic and conventional pigs during the process. Indeed, only one S. Typhimurium PFGE profile was evidenced for organic and conventional carcasses during the same sampling day. This study gives for the first time data on Salmonella in organic pig production in France

Campylobacter in organic and conventional pig productions in France: occurrence, antibiotic resistance and genetic diversity

The objectives of this study were to assess the occurrence of Campylobacter in organic and conventional pig productions, and to evaluate their antimicrobial resistance and genetic diversity in these two productions. Sampling was realized in one slaughterhouse: 31 organic herds and 31 conventional herds were considered. Detection of Campylobacter was done on respectively 56 and 58 organic and conventional pig colon contents, and on 60 carcass swabs for each production. Campylobacter strains were studied for their resistance to 8 antibiotics and for their genetic diversity through PFGE using KpnI enzyme. Occurrence in colon content was not significantly different between organic (76.8%) and conventional pigs (74.0%). Only one conventional carcass was contaminated by Campylobacter. All the Campylobacter were C. coli. A total of 266 C. coli were characterized: 138 and 124 from colon content of organic and conventional pigs, respectively, and 4 from carcass. Only 10 isolates were pansusceptible. The most frequent resistance profile was resistance to streptomycin with tetracycline (24.2% and 33.3% of the isolates from conventional and organic pigs, respectively). Isolates from conventional pigs were significantly more frequently resistant to tetracycline and erythromycin, often in association with other resistances: 53.1% of isolates from conventional pigs were resistant to 3 or more antibiotics families compared to 26.8% from organic pigs. The 240 typable isolates were distributed in 122 KpnI profiles. Only one KpnI profile was common for 1 organic and 1 conventional isolates. Index of diversity was very high (ID>0.98) in both productions. This study showed that occurrence and diversity of Campylobacter in organic and conventional pigs are similar. The lower level of antibiotic resistance for organic pigs may be related to the restricted use of antibiotics in this production and / or colonization of organic pigs with susceptible environmental strains

Comparison of organic and conventional pig productions on prevalence, antibiotic resistance and genetic diversity of Escherichia coli

In this part of a CORE Organic II funded project, the objectives were 1) to assess the occurrence of E. coli in organic pig production, in comparison with conventional production, 2) to estimate the E. coli tetracycline resistance level in pig of the two productions, and 3) to evaluate the genetic diversity of strains isolated from these two productions. 25 organic herds and 25 conventional herds were considered in one slaughterhouse from April to October 2012. Two pigs per herds were considered. For each pig, numeration of Escherichia coli and of tetracycline resistant E. coli (TET+E.coli), were realized from colon content. Level of tetracycline resistance for each sample was then determined by the % of tetracycline resistant E. coli from the total number of E. coli. From colon content, on the 100 sampled pigs, E. coli was detected for all the organic pigs (n=50) and conventional (n=50). TET+E.coli was detected for 49 organic pigs (98%) and 48 conventional pigs (96%). The number of E. coli per gram of colon content were significantly higher (6.81 log10UFC/g) than for organic pigs (6.19 log10UFC/g) (p=0.0033). A significant difference for the number of TET+E.coli per gram of colon content was also observed between organic (5.68 log10UFC/g) and conventional pigs (6.33 log10UFC/g) (p=0.00021). The level of tetracycline resistance is significantly (p=0.0033) higher for conventional pigs (57.4%) than for organic pigs (37.9%). A total of 374 E. coli and TET+E.coli isolates were collected. After typing by PFGE using XbaI enzyme, isolates were distributed in 275 pulsotypes. No pulsotype was common between organic and conventional. The diversity is very high, ID=0.997. Inside each production, only 2 pulsotypes was common between two herds. PFGE profiles didn’t permit to associate strains to their origin

Résistance à la tétracycline et diversité génétique d’Escherichia coli isolés de porcs biologiques et de porcs conventionnels

The objectives of this study were to assess the prevalence, tetracycline resistance level and genetic diversity of Escherichia coli isolated from organic pigs in comparison with conventional pigs. 25 organic and 25 conventional herds were considered in one slaughterhouse from April to October 2012. Colon content of 2 pigs per herd was sampled. For each pig, E. coli and tetracycline resistant E. coli (TET+E. coli) were enumerated. Level of tetracycline resistance was then calculated. Isolates were typed by PFGE using XbaI enzyme. E. coli was detected for all the organic (n=50) and conventional pigs (n=50). TET+E. coli was detected for 49 organic (98%) and 48 conventional pigs (96%). The number of E. coli per gram of colon content was significantly higher for conventional (6.81 log10 UFC/g) than for organic pigs (6.19 log10 UFC/g) as well as the number of TET+E. coli with 6.33 log10 UFC/g for conventional pigs and 5.68 log10 UFC/g for organic pigs. Finally, the level of tetracycline resistance was also significantly higher (p=0.0033) for conventional (57.4%) than for organic pigs (37.9%). PFGE was carried out on 374 E. coli; they were distributed in 275 pulsotypes. The genetic diversity was very high (Dvalue=0.997). No pulsotype was common to both organic and conventional pigs. Results suggest that farm managements may have an impact on the amount of E. coli excreted and on their antibiotic resistance. However, it is difficult to estimate the impact on human health with 0.65 log10 UFC/g difference between the two productions. Diversity of strains is so high that it is difficult to associate strains to a production

Campylobacter chez les porcs biologiques et conventionnels: prévalence et antibiorésistance

Cette étude a pour objectif d’obtenir et comparer des données de prévalence et de résistance aux antibiotiques de Campylobacter isolés de porcs issus de la production biologique porcine et de la production conventionnelle. Des prélèvements de contenus de colon et des chiffonnettes de carcasses ont été réalisés en 2012, dans un abattoir, sur 31 lots de porcs biologiques et 31 lots de porcs conventionnels (1 ou 2 porcs par lot). La détection de Campylobacter a été réalisée par isolement direct sur gélose Karmali. Le genre Campylobacter et l’espèce des isolats collectés ont été confirmés par PCR. La résistance aux antibiotiques des isolats a été recherchée pour 5 familles d’antibiotiques (Gentamicine et streptomycine, Ciprofloxacine et Acide Nalidixique, Tétracycline (TET), Erythromycine (ERY) et chloramphénicol) par détermination des concentrations minimales inhibitrices (CMI) et interprétation selon les cut-offs épidémiologiques EUCAST. 114 contenus fécaux (56 biologiques et 58 conventionnels) et 120 chiffonnettes de carcasses (60 biologiques et 60 conventionnels) ont été analysés. Les Campylobacter isolés sont de l’espèce C. coli. La prévalence dans les contenus de colon n’est pas significativement différente entre les porcs biologiques (76,8%) et conventionnels (74,0%). C. coli n’a été détecté que sur 1 carcasse de porc conventionnel. Parmi les 264 isolats de C. coli isolés de contenus du colon (140 de porcs biologiques et 124 de porcs conventionnels), seuls 10 isolats sont sensibles aux 5 familles d’antibiotiques. 147 isolats sont résistants à 1 ou 2 familles d’antibiotiques et 107 sont multirésistants (≥ à 3 familles d’antibiotiques). Le profil de résistance majoritaire est la résistance couplée STR-TET, observée pour respectivement 21,8% et 32,9% des isolats issus de porcs conventionnels et biologiques. Entre les deux productions, une différence est observée pour TET et ERY. Les isolats provenant de porcs conventionnels sont significativement (p<0,01) plus souvent résistants à ces 2 antibiotiques, souvent en association avec d’autres résistances: 54,8% des isolats de porcs conventionnels sont multirésistants contre 27,9% des isolats de porcs biologiques (p<0,01). Cette étude montre que le portage de Campylobacter par les porcs est identique quel que soit le type de production. Le niveau plus faible de taux de résistance aux antibiotiques pour les Campylobacters issus de porcs biologiques pourrait être lié à l’usage restreint d’antibiotiques en production biologique et/ou à la colonisation des porcs biologiques par des souches sauvages sensibles

First description of Campylobacter lanienae from feces of organic and conventional pigs, in France

In the frame of the CORE Organic II funded European project SafeOrganic, fecal samples of 58 conventional pigs and 56 organic pigs, originated from 31 organic herds and 31 conventional herds, were collected in a slaughterhouse in order to isolate Campylobacter coli. Direct streaking from feces and incubation at 37°C of the Karmali plates allowed the isolation of another Campylobacter species: Campylobacter lanienae. Indeed, among the 381 typical Campylobacter colonies isolated, it was not possible to identify the species for 118 isolates with the Wang’s multiplex-PCR. However, 85 of these isolates were confirmed C. lanienae by Maldi-Tof and by 16S rRNA PCR. With the two species, coli and lanienae, the occurrence of Campylobacter in pig was estimated to 87.9% (51/58) for conventional pigs and 96.5% (52/56) for organic pigs. A total of 55 isolates of C. lanienae were tested for their resistance to 7 antibiotics. Only one was pansusceptible. Natural resistance of this species to Nalidixic acid was confirmed. Resistance to Tetracycline was significantly different between the two productions (p to 0.98). No link between PFGE profile and isolate origin or antibiotic resistance pattern was evidenced. This study allowed us to demonstrate for the first time in France that pigs may also carry in their feces a species rarely highlighted: C. lanienae. The lower level of antibiotic resistance and multiresistance of C. lanienae strains for organic pigs may be related to the restricted use of antibiotics in this production

No Clear Differences between Organic or Conventional Pig Farms in the Genetic Diversity or Virulence of Campylobacter coli Isolates

To evaluate the impact of pig farm management on the genetic diversity and on the virulence of Campylobacter coli, we characterized isolates from 19 organic pig farms (62 isolates) and from 24 conventional pig farms (58 isolates). The 120 C. coli isolates were typed using pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) and the presence of nine virulence genes was screened using real-time PCR. The capacity of adhesion and invasion of 61 isolates (32 from organic and 29 from conventional farms)were then tested on human intestinal Caco-2 cells. A total of 59 PFGE types and of 50 sequence types (STs) were identified. Twelve PFGE types and nine STs, accounting for 34 and 41.6%of the isolates, respectively, were common between the two production systems with ST854 dominating (18.3% of the isolates). Twenty-nine PFGE types and 25 STs were only found in isolates from organic farms, and 18 PFGE types and 16 STs from conventional farms. No significant differences were found in diversity despite the differences in rearing systems, except at the locus level for the glnA, gltA, and uncA genes. All isolates, regardless of their origin, carried the ceuE, iam, ciaB, and flaA genes and more than 95% of the isolates carried the cadF and cdtABC genes. No significant differences were found in pathogenicity between the two farming systems. The pathogenicity of the C. coli isolates was low compared to C. jejuni control strains tested. The plasmid gene virb11 was detected in only 13 isolates from organic farms; these isolates showed greater invasion capacity than those without this gene. Our study indicates that pig farm management does not significantly affect the diversity and the virulence of Campylobacter coli isolated from pigs. The common genotypes between conventional and organic farms may indicate that some genotypes are adapted to pigs

Kinetic reactive transport modelling of column tests for uranium In Situ Recovery (ISR) mining

International audienceNumerical modelling of the interaction between solution and rock is examined in order to improve the management of U In Situ Recovery (ISR) mining. Two ‘classical’ types of leaching experiments were performed: (1) tests in batch reactors; and (2) extraction in flow-through columns. A comprehensive interpretation of the complete leaching test results (mineralogy of the samples and chemical analysis of leachates) led to the development of a conceptual model with reasonable assumptions about dissolution and precipitation reactions during the acid leach of the columns. This conceptual model was tested and validated by numerical modelling of the two types of laboratory experiments. Batch experiments were simulated with the geochemical code CHESS in order to model the leachate solutions and to calibrate the geochemical reaction paths and their kinetic laws. The geochemical models with kinetics successfully simulated the trend of leachate’ chemistry in the two types of experimental tests (batch and column). They resulted in a proposal of a 1D hydrogeochemical transport model of the ISR process at laboratory-scale. Furthermore, a sensitivity analysis conducted on the 1D-calibrated model made it possible (1) to determine factors controlling leaching reactions; and (2) to quantify their respective influence on the uranium recovery in terms of acid consumption and leachate volume to treat in the plant

Evolution of iron speciation during hydration of C4 AF

International audienceIt is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C(4)AF is not well defined. In other systems like in soils or sediments iron phases play a key role in the fixation of pollutant. In cement sorption isotherms, indicated that various metals can be retained by the C(4)AF hydrated products. Therefore the capabilities of those phase to retain heavy metal should not be neglected. Previous investigations have shown that the minerals formed during the hydration of C(4)AF are similar to those formed from C3A (pure tri-calcium aluminate) under comparable conditions. Nevertheless no investigation was conducted at the molecular level and there is still a controversy whether Fe substitutes for Al in the hydrated minerals in whole or in part, or if it forms FeOOH clusters scattered throughout the matrix. In this context we have conducted XAS experiments using synchrotron radiation. It was found that the hydration of C(4)AF forms C(3)AH(6) (hydrogarnet) in which Fe randomly substitutes for Al as well as an amorphous FeOOH phase. Intermediate products like AFm (i.e., an ill organized lamellar phase) are also formed but rapidly evolve to C(3)AH(6); iron does not seem to be incorporated in the AFm structure