Bacteria In Pigs Research Articles

Cell migration and proliferation capacity of IPEC-J2 cells after short-chain fatty acid exposure.

Novel antimicrobial strategies are necessary to tackle using antibiotics during the suckling and weaning period of piglets, often characterized by E. coli-induced diarrhea. In the last decades, acetate, propionate, and butyrate, all short-chain fatty acids (SCFAs), have been proposed as an alternative to antibiotics. SCFAs are instrumental in promoting the proliferation of enterocytes, preserving intestinal integrity, and modulating the microbial community by suppressing the growth of pathogenic bacteria in pigs. The effect of individual SCFAs (proprionate, acetate and butyrate) on the regenerative capacity of intestinal cells was investigated via an optimized wound-healing assay in IPEC-J2 cells, a porcine jejunal epithelial cell line. IPEC-J2 cells proved a good model as they express the free fatty acid receptor 2 (FFAR2), an important SCFA receptor with a high affinity for proprionate. Our study demonstrated that propionate (p = 0.005) and acetate (p = 0.037) were more effective in closing the wound than butyrate (p = 0.190). This holds promise in using SCFA's per os as an alternative to antibiotics.

Novel sensitive isothermal-based diagnostic technique for the detection of African swine fever virus.

A rapid, simple, and sensitive diagnostic technique for the detection of African swine fever virus (ASFV) nucleic acid was developed for testing clinical samples in the field or resource-constrained settings. In the current study, the saltatory rolling-circle amplification (SRCA) technique was used for the first time to detect ASFV. The technique was developed using World Organization for Animal Health (WOAH)-approved primers targeting the p72 gene of the ASFV genome. The assay can be performed within 90 minutes at an isothermal temperature of 58°C without a requirement for sophisticated instrumentation. The results can be interpreted by examination with the naked eye with the aid of SYBR Green dye. This assay exhibited 100% specificity, producing amplicons only from ASFV-positive samples, and there was no cross-reactivity with other pathogenic viruses and bacteria of pigs that were tested. The lower limits of detection of SRCA, endpoint PCR, and real-time PCR assays were 48.4 copies/µL, 4.84 × 103 copies/µL, and 4.84 × 103 copies/µL, respectively. Thus, the newly developed SRCA assay was found to be 100 times more sensitive than endpoint and real-time PCR assays. Clinical tissue samples obtained from ASFV-infected domestic pigs and other clinical samples collected during 2020-22 from animals with suspected ASFV infection were tested using the SRCA assay, and a 100% accuracy rate, negative predictive value, and positive predictive value were demonstrated. The results indicate that the SRCA assay is a simple yet sensitive method for the detection of ASFV that may improve the diagnostic capacity of field laboratories, especially during outbreaks. This novel diagnostic technique is completely compliant with the World Health Organization's "ASSURED" criteria advocated for disease diagnosis, as it is affordable, specific, sensitive, user-friendly, rapid and robust, equipment-free, and deliverable. Therefore, this SRCA assay may be preferable to other complex molecular techniques for diagnosing African swine fever.

Presence of antibiotic-resistant bacteria in pigs for consumption - one health challenge - Literature review

Pig farming is an area of livestock that has been developing the most in Brazil and the world, with production increasing every year, generating jobs, and being of great importance for the Brazilian economy. In swine production, great health enables these animals to reach their highest point of development and antimicrobials are used, either prophylactically or through food, as growth promoters. Within swine culture, there is a concern regarding antibiotic-resistant bacteria; however, Staphylococcus spp. do not receive the necessary prominence in research, since the pathologies caused by them do not tend to cause great economic losses. Therefore, this review aimed to highlight the importance of bacterial resistance within breeding stock, its possible origins, the importance of Staphylococcus spp. within this topic, and its evolution in swine farming over the years. For this, studies were selected, with an emphasis on information such as country, number of samples, presence of Staphylococcus spp. resistant to methicillin, breeding phase, and phenotypic and molecular tests. In addition, publications were selected that show the importance of understanding the biological and resistance profiles of Staphylococcus spp. in swine herds in Brazil and around the world.

Age influences the temporal dynamics of microbiome and antimicrobial resistance genes among fecal bacteria in a cohort of production pigs

BackgroundThe pig gastrointestinal tract hosts a diverse microbiome, which can serve to select and maintain a reservoir of antimicrobial resistance genes (ARG). Studies suggest that the types and quantities of antimicrobial resistance (AMR) in fecal bacteria change as the animal host ages, yet the temporal dynamics of AMR within communities of bacteria in pigs during a full production cycle remains largely unstudied.ResultsA longitudinal study was performed to evaluate the dynamics of fecal microbiome and AMR in a cohort of pigs during a production cycle; from birth to market age. Our data showed that piglet fecal microbial communities assemble rapidly after birth and become more diverse with age. Individual piglet fecal microbiomes progressed along similar trajectories with age-specific community types/enterotypes and showed a clear shift from E. coli/Shigella-, Fusobacteria-, Bacteroides-dominant enterotypes to Prevotella-, Megaspheara-, and Lactobacillus-dominated enterotypes with aging. Even when the fecal microbiome was the least diverse, the richness of ARGs, quantities of AMR gene copies, and counts of AMR fecal bacteria were highest in piglets at 2 days of age; subsequently, these declined over time, likely due to age-related competitive changes in the underlying microbiome. ARGs conferring resistance to metals and multi-compound/biocides were detected predominately at the earliest sampled ages.ConclusionsThe fecal microbiome and resistome—along with evaluated descriptors of phenotypic antimicrobial susceptibility of fecal bacteria—among a cohort of pigs, demonstrated opposing trajectories in diversity primarily driven by the aging of pigs.

Survey on Carbapenem-Resistant Bacteria in Pigs at Slaughter and Comparison with Human Clinical Isolates in Italy.

This study is focused on resistance to carbapenems and third-generation cephalosporins in Gram-negative microorganisms isolated from swine, whose transmission to humans via pork consumption cannot be excluded. In addition, the common carriage of carbapenem-resistant (CR) bacteria between humans and pigs was evaluated. Sampling involved 300 faecal samples collected from slaughtered pigs and 300 urine samples collected from 187 hospitalised patients in Parma Province (Italy). In swine, MIC testing confirmed resistance to meropenem for isolates of Pseudomonas aeruginosa and Pseudomonas oryzihabitans and resistance to cefotaxime and ceftazidime for Escherichia coli, Ewingella americana, Enterobacter agglomerans, and Citrobacter freundii. For Acinetobacter lwoffii, Aeromonas hydrofila, Burkolderia cepacia, Corynebacterium indologenes, Flavobacterium odoratum, and Stenotrophomonas maltophilia, no EUCAST MIC breakpoints were available. However, ESBL genes (blaCTXM-1, blaCTX-M-2, blaTEM-1, and blaSHV) and AmpC genes (blaCIT, blaACC, and blaEBC) were found in 38 and 16 isolates, respectively. P. aeruginosa was the only CR species shared by pigs (4/300 pigs; 1.3%) and patients (2/187; 1.1%). P. aeruginosa ST938 carrying blaPAO and blaOXA396 was detected in one pig as well as an 83-year-old patient. Although no direct epidemiological link was demonstrable, SNP calling and cgMLST showed a genetic relationship of the isolates (86 SNPs and 661 allele difference), thus suggesting possible circulation of CR bacteria between swine and humans.

Antibiotic resistant Escherichia coli from diarrheic piglets from pig farms in Thailand that harbor colistin-resistant mcr genes

Antibiotic-resistant Escherichia coli is one of the most serious problems in pig production. This study aimed to determine the antibiotic susceptibility and genotypes profiles of diarrhoeagenic E. coli that causes diarrhea in piglets. Thirty-seven pathogenic E. coli strains were used in this study. These were isolated from rectal swabs of diarrheic piglets from farms in Thailand from 2018 to 2019. Escherichia coli isolates were highly resistant to amoxicillin (100%), followed by oxytetracycline (91.9%), enrofloxacin (89.2%), trimethoprim/sulfamethoxazole (86.5%), amoxicillin: clavulanic acid (81.1%), colistin and gentamicin (75.7%), ceftriaxone and ceftiofur (64.9%), ceftazidime (35.1%) and 97.3% showed multidrug-resistance (MDR). There were 8 (21.6%) mcr-1 carriers, 10 (27.0%) mcr-3 carriers and 10 (27.0%) co-occurrent mcr-1 and mcr-3 isolates. The phenotype-genotype correlation of colistin resistance was statistically significant (performed using Cohen’s kappa coefficient (κ = 0.853; p < 0.001)). In addition, PCR results determined that 28 of 37 (75.7%) isolates carried the int1 gene, and 85.7% int1-positive isolates also carried the mcr gene. Genetic profiling of E. coli isolates performed by ERIC-PCR showed diverse genetics, differentiated into thirteen groups with 65% similarity. Knowledge of the molecular origins of multidrug-resistant E. coli should be helpful for when attempting to utilize antibiotics in the pig industry. In terms of public health awareness, the possibility of transmitting antibiotic-resistant E. coli from diarrheic piglets to other bacteria in pigs and humans should be of concern.

Intestinal microbiota disturbance affects the occurrence of African swine fever

Intestinal microbiota not only participates in the digestion and absorption of nutrients, but also plays an important role in regulating host metabolism and health. The current study aimed to explore the intestinal microbiota characteristics in pigs infected with African swine fever. Below the same term, fresh fecal samples of sick and healthy pigs were collected. Primers were designed and PCR was extracted based on the 16S rDNA gene of bacteria by Illumina NovaSeq sequencing platform. The results showed that the bacterial alpha diversity index of healthy pigs was significantly higher than that of sick pigs (p < 0.05). On the phylum taxa, dominant bacteria more than 98.5% in the two groups are composed of Firmicutes, Spirobacteria, and Bacteroides, of which the abundance of Firmicutes and Bacteroidetes decreased and Spiricobacteria increased extremely significant in sick pigs (p < 0.01). On the genus taxa, the relative abundance of Oscillospira, Streptococcus and Roseburia decreased significantly (p < 0.05). Most notably, Treponema performed excellently in distinguishing pigs infected with African swine fever with the abundance increased extremely significantly (p < 0.01). In conclusion, African swine fever could alter the abundance of dominant bacteria in pigs, and Treponema may be one of the important inducers for swine pathogenicity. Highlights The bacterial population composition in sick pigs and healthy pigs was basically similar, but the relative abundance of dominant bacteria was significantly difference. ASF could alter the abundance of dominant bacteria in pigs, and Treponema may be one of the important inducers for swine pathogenicity. These results will provide further evidence for the ASF infection in local pig farms and provide reference for their microecological control, which has important practical significance and social value for effective control of ASF, stability of pig production and guarantee of market supply.

Efficacy of phage therapy in pigs: systematic review and meta-analysis.

Limits on the use and efficacy of various antibiotics coupled with negative consumer perception of the practice have together spurred substantial research into compounds that could reduce the use antibiotics to control bacterial diseases in pigs. Bacteriophages are often among such potential compounds, and various groups have examined the efficacy of bacteriophages or bacteriophage products in limiting transmission or colonization of targeted bacteria. The study presented here provides a systematic review of such studies followed by a meta-analysis of aggregated data produced by each study. The data set was limited to inputs (n = 19; 576 total observations) from studies where: 1) live pigs were inoculated with a known quantity of challenge bacteria; 2) challenged animals were treated with a known quantity of phages; 3) concentrations of the challenge bacteria were measured in different tissues/fluids following phage treatment; and 4) SD (or SE to allow calculation of SD) was reported. Concentrations of challenge bacteria were significantly lower in phage-treated pigs versus challenged but untreated pigs (P < 0.0001; effect size = −1.06 1log10 colony-forming units [CFU]/g). The effect size of phage treatment was significantly greater (P < 0.05) in samples collected 48 to 96 h following phage treatment versus those collected ≤ 24 h following phage treatment. Likewise, effect size of phage treatment was significantly greater in piglets versus market-weight pigs. Across observations, phage treatment effect sizes were greatest (P < 0.01) in fecal samples versus ileal or cecal samples. Taken together, these data indicate that phage treatment can significantly reduce the concentrations of targeted bacteria in pigs; scenarios exist, however, where phage treatment could predictably be more or less effective.

Detection of Helicobacter suis bacteria in pigs of different age groups

Currently, the pathogenesis of gastric ulcer in pigs remains largely unexplored. The origin of this pathology is most often associated with the type and the technologies of feeding, stresses and disorders of homeostasis of the animal body. The possible involvement of bacteria of the genus Helicobacter in the development of chronic gastritis and gastric ulcer disease in pigs was suggested by the researchers relatively recently. The article comprises the results of investigations aimed at detection of Helicobacter suis bacteria and the contamination degree of porcine gastric mucosa in pigs of different age groups. The stomachs, obtained from suckling pigs, fattening pigs and sows in the slaughterhouse of the Mari El Republic, were examined. The study determined the dependence of pathomorphological changes in the gastric mucosa of pigs on the detection of H. suis in microscopic and biochemical tests as well as in PCR. Thus, no pathomorphological changes in the gastric mucosa of suckling pigs were detected. Severe hyperkeratosis, erosions, and ulcers were found on the stomach mucosa of fattening pigs and sows that were infected with H. suis bacteria. Sows also had ulcerative lesions in the non-glandular region of esophagus. In the biomaterial of suckling piglets the DNA of H. suis bacteria was found only in the pyloric region of the stomach, while in fattening pigs, the DNA of these bacteria was most often isolated from the fundal region, and in sows – from the fundal and cardial regions. This indicates a shift in colonization by helicobacters of the mucous membrane of the stomach from the pyloric to the cardiac sectionincreased with animal age. The obtained research data provide the additional evidence of the etiological role of H. suis in the pathogenesis of gastric ulcer in pigs.

Carbohydrates effects on nutrition and health functions in pigs.

The greatest improvement in carbohydrates studies on pig nutrition and health is that carbohydrates are classified more clearly, which is based not only on their chemical structure but also on their physiological characteristics. Besides its primary energy source, different types and structures of carbohydrates are a benefit for nutrition and health functions in pigs, which are involved in promoting growth performance and intestinal functions, regulating the community of gut microbiota, and modulating the lipids and glucose metabolism. The underlying mechanism of carbohydrates regulates the lipids and glucose metabolism through their metabolites (short-chain fatty acids [SCFAs]) and mainly via the SCFAs-GPR43/41-PYY/GLP1, SCFAs-AMP/ATP-AMPK, and SCFAs-AMPK-G6Pase/PEPCK pathways. Emerging research had evaluated an optimal combination in different types and structures of carbohydrates, which could enhance growth performance and nutrient digestibility, promote intestinal functions, and increase the abundances of butyrate-producing bacteria in pigs. Overall, compelling evidence supports the notion that carbohydrates play important roles in both nutrition and health functions in pigs. Moreover, identifying the carbohydrates combinations will be of both theoretical and practical values for developing the technology of carbohydrates balance in pigs.

18 Impact of in-feed vs. in-water antibiotic administrations on the fecal prevalence and antimicrobial susceptibilities of Campylobacter and Salmonella in piglets

Abstract Campylobacter and Salmonella are common food borne pathogens in the gut of pigs and are shed in the feces. The control of these bacteria in pigs is of importance in reducing the potential for transmission to humans. In swine, oral route, either in-feed or in-water, is by far the most common route of administration of antibiotics. Because the distribution of the antibiotic in the gut and the dosage are different, the impact of in-feed vs. in-water administration of antibiotics on the fecal shedding of food borne pathogens, Campylobacter and Salmonella, and on the development of antimicrobial resistance (AMR) in gut bacteria is a largely unexplored area. Therefore, a study was conducted to compare the effects of in-feed and in-water antibiotic administration on fecal prevalence of Campylobacter and Salmonella and AMR development in nursery piglets. A total of 1,296 weaned piglets were allocated into pens (48 pens; 27 pigs per pen) distributed in a single room. Pens were assigned randomly to six treatment groups; Control (No antibiotic), In-feed chlortetracycline (CTC), In-water CTC, In-feed tiamulin, In-water tiamulin, and a combination of CTC and tiamulin (In-feed). Fresh fecal samples were collected randomly from 5 of 27 piglets from each pen on pre-treatment (days -7, 0), treatment (days 7, 14) and post-treatment (days 21, 28) phases. Bacterial isolations and identifications were done by culture method and PCR, respectively. Overall prevalence of Campylobacter and Salmonella were 18.2% (262/1,440) and 3.9% (56/1,440) respectively. Speciation of Campylobacter isolates indicated C. hyointestinalis (17.9%; 258/1,440) and C. coli (0.3%; 4/1,440). Pigs from control group had a higher prevalence (P&amp;lt; 0.05) of both Campylobacter and Salmonella when compared to other treatment groups. Both treatment and post-treatment phases had a significant effect on the prevalence of Campylobacter and Salmonella (P&amp;lt; 0.05).

Antimicrobial use and detection of cefotaxime-resistant Enterobacteriaceae in the pig production chain, Ogun State, Nigeria

Cefotaxime belongs to the third-generation cephalosporin group of antimicrobials, which are classified as critical for the treatment of infections in humans. The upsurge in the incidence of cefotaxime-resistant (C-R) bacteria from animal sources is of global public health importance. This study investigated the pres- ence of C-R Enterobacteriaceae in the pig production chain in Ogun State, Nigeria, and examined C-R isolates for production of extended-spectrum b-lactamase (ESBL). The knowledge, attitude and practices of pig farmers regarding antimicrobial usage were also investigated. C-R bacteria were detected in 54 (17.8%) out of 303 samples. C-R isolates were identified as Escherichia coli (n = 22), Klebsiella spp. (n = 17), Enterobacter aerogenes (n = 10) and Citrobacter freundii (n = 5). The organisms were present in feces from on-farm pigs (15/109; 13.7%), fresh pork at slaughterhouses (19/40; 47.5%), frozen pork at retail shops (7/28; 25.0%), cutting surfaces of butchers’ tools (7/52; 13.5%), and abattoir effluent water (6/41; 14.6%). No C-R bacteria were detected in ready-to-eat pork. Three isolates of Es. coli and one of K. pneumoniae were ESBL-producers and pos- sessed blaCTX-M-15 ESBL gene variant. ESBL-producing Es. coli belonged to phylo- genetic group A. All C-R isolates were resistant to more than three antimicrobials from different classes of antimicrobials. Tetracycline, ampicillin, amoxicillin, ciprofloxacin and enrofloxacin were among the commonly used antimicrobials in pig production, whereas cephalosporins were rarely used. Farmers knew that pigs could serve as reservoirs of pathogenic bacteria transmissible to humans. However, they were not aware that the use of antimicrobials in pig production could lead to the development and proliferation of antimicrobial-resistant bacteria in pigs. Efforts should be made to improve awareness among farmers on the roles of antimicrobial use in the emergence and dissemination of antimicrobial-resistant bacteria in animal production.

Application of PCR technique in diagnosis of four respiratory pathogenic bacteria in pigs at the slaughterhouse

The polymerase chain reaction (PCR) for Actinobacillus pleuropneumonia (App), Haemophilus parasuis (Hps), Pasteurella multocida (Pm) and Bordetella bronchiseptica (Bb) were performed in pure colonies isolated from 114 lung specimens with lesions collected from the Vissan slaughterhouse in Ho Chi Minh City from July 2018 to May 2019. The aim of the experiment was to identify the four respiratory pathogenic bacteria in pigs at slaughterhouse by using PCR technique. The criteria for evaluating the results included the proportion of positive samples with multiplex PCR and percentage of samples co-infected with 2, 3, and 4 bacteria. Among a total of 114 injured lung samples, 21% of the samples was positive to at least one of the four bacteria, 3 samples (2.63%) were positive for App, 2 samples (1.75%) were positive for Hps, 7 samples (6.14%) were for Pm, and 12 lungs (10.53%) were positive for Bb. One sample (0.88%) was found co-infected with Pm and Hps.

Autochthonous lactic acid bacteria isolated from pig faeces in Thailand show probiotic properties and antibacterial activity against enteric pathogenic bacteria

Lactic acid bacteria (LAB) play an important role in pig health and performance that arises from their beneficial impacts on the balance of gastrointestinal microbes, ability to fight enteric pathogens, and capacity to support the immune system. The aim of this study was to evaluate the functional and safety aspects of five previously isolated autochthonous LAB strains, (Lactobacillus plantarum 22F, 25F and 31F, Pediococcus acidilactici 72N and Pediococcus pentosaceus 77F) from pig faeces as potential probiotics for a pig feed supplement. The functional and safety properties of the strains were assessed by in vitro tests. The functional properties tested were their abilities in tolerating low pH values under simulated gastric conditions, their cell surface properties (hydrophobicity, auto- and co-aggregation), antibacterial activity against the common enteric pathogenic bacteria in pigs (such as pathogenic Escherichia coli, Salmonella Choleraesuis and Streptococcus suis), and diacetyl production. The safety of the strains was analyzed based on the absent of haemolysis on blood and bile salt hydrolase activity. Although all strains demonstrated diacetyl production, good survivability and antibacterial activities, L. plantarum 22F and 25F showed the best performance with the strongest antibacterial actions against the indicator pathogens. Of the strains, only P. pentosaceus 77F exhibited haemolysis or bile salt hydrolase activity. Furthermore, a principal component analysis revealed that L. plantarum 22F possessed superior functional and safety aspects compared to the other four autochthonous strains and to reference strains L. plantarum JCM 1149 and P. acidilactici DSM 20284. Further in vivo studies using oral administration of the strains are justified to assess their effectiveness as feed supplements for pigs.

Activation of Pyruvate Dehydrogenase by Sodium Dichloroacetate Shifts Metabolic Consumption from Amino Acids to Glucose in IPEC-J2 Cells and Intestinal Bacteria in Pigs.

The extensive metabolism of amino acids (AA) as fuel is an important reason for the low use efficiency of protein in pigs. In this study, we investigated whether regulation of the pyruvate dehydrogenase kinase (PDK)/pyruvate dehydrogenase alpha 1 (PDHA1) pathway affected AA consumption by porcine intestinal epithelial (IPEC-J2) cells and intestinal bacteria in pigs. The effects of knockdown of PDHA1 and PDK1 with small interfering RNA (siRNA) on nutrient consumption by IPEC-J2 cells were evaluated. IPEC-J2 cells were then cultured with sodium dichloroacetate (DCA) to quantify AA and glucose consumption and nutrient oxidative metabolism. The results showed that knockdown of PDHA1 using siRNA decreased glucose consumption but increased total AA (TAA) and glutamate (Glu) consumption by IPEC-J2 cells ( P < 0.05). Opposite effects were observed using siRNA targeting PDK1 ( P < 0.05). Additionally, culturing IPEC-J2 cells in the presence of 5 mM DCA markedly increased the phosphorylation of PDHA1 and PDH phosphatase 1, but inhibited PDK1 phosphorylation ( P < 0.05). DCA treatment also reduced TAA and Glu consumption and increased glucose depletion ( P < 0.05). These results indicated that PDH was the regulatory target for shifting from AA metabolism to glucose metabolism and that culturing cells with DCA decreased the consumption of AAs by increasing the depletion of glucose through PDH activation.

Purified natural pig immunoglobulins can substitute dietary zinc in reducing piglet post weaning diarrhoea

Enteric infectious disease in weaner piglets, including postweaning diarrhoea (PWD), are usually treated and/or prevented with antibiotics and/or zinc oxide in the piglet feed. However extensive use of antibiotics and zinc oxide in intensive animal production is unwanted as it may promote microbial antibiotic resistance and pose environmental problems. Recently, in an experimental model of PWD, we observed that oral administration of purified porcine immunoglobulin G (ppIgG) from pooled natural pig plasma could reduce enteric infection. In the present study we were able to reproduce these results as it was observed that oral ppIgG accelerated clearance of faecal haemolytic bacteria in pigs challenged with E. coli in comparison with pigs not receiving ppIgG. This effect was observed upon feeding ppIgG for seven days postweaning suggesting that ppIgG does not have to be used prophylactically for several days preweaning. Furthermore, the effect of oral administration of ppIgG for seven days postweaning was equal to or better than that of dietary zinc oxide in reducing diarrhoea symptoms and in clearing faecal haemolytic bacteria for 14days postweaning. These observations warrant future trials of dietary ppIgG in intensive swine production units to establish its performance as an alternative to dietary antibiotics and zinc oxide for preventing PWD.

A Unique Capsule Locus in the Newly Designated Actinobacillus pleuropneumoniae Serovar 16 and Development of a Diagnostic PCR Assay.

ABSTRACTActinobacillus pleuropneumoniae causes pleuropneumonia, an economically significant lung disease of pigs. Recently, isolates of A. pleuropneumoniae that were serologically distinct from the previously characterized 15 serovars were described, and a proposal was put forward that they comprised a new serovar, serovar 16. Here we used whole-genome sequencing of the proposed serovar 16 reference strain A-85/14 to confirm the presence of a unique capsular polysaccharide biosynthetic locus. For molecular diagnostics, primers were designed from the capsule locus of strain A-85/14, and a PCR was formulated that differentiated serovar 16 isolates from all 15 known serovars and other common respiratory pathogenic/commensal bacteria of pigs. Analysis of the capsule locus of strain A-85/14 combined with the previous serological data show the existence of a sixteenth serovar—designated serovar 16—of A. pleuropneumoniae.

Prevalentie van antimicrobiële resistentie van pathogene en commensale Escherichia coli bij voedselproducerende dieren in België

In dit artikel worden gedetailleerde studies over antimicrobiële resistentie van commensale E. coli bij varkens, runderen, pluimvee en vleeskalveren en pathogene E. coli bij varkens en runderen in België beschreven voor 2011. Bij commensale E. coli-isolaten van pluimvee en vleeskalveren werd een hogere prevalentie van antimicrobiële resistentie vastgesteld dan bij isolaten van varkens en runderen. Vijftig procent van de E. coli-isolaten van vleeskuiken was resistent tegen ten minste vijf antimicrobiële middelen, terwijl 61% van de isolaten van runderen gevoelig was voor alle geteste antibiotica. Daarentegen vertoonden pathogene E. coli-isolaten van runderen een uitgebreid resistentieprofiel, met resistentie tegen tien of meer antimicrobiële middelen bij meer dan de helft van de isolaten. De resultaten zijn niet significant verschillend van de resultaten van eerder gepubliceerde studies over commensale bacteriën bij varkens en vleeskuikens in België, hoewel er verschillende methoden van bemonstering en gevoeligheidstesten werden gebruikt.

High-level recombinant human lysozyme expressed in milk of transgenic pigs can inhibit the growth of Escherichia coli in the duodenum and influence intestinal morphology of sucking pigs.

Lysozyme is often used as a feed additive and acts as an antimicrobial protein that enhances immune function and defends against pathogenic bacteria in pigs. In this study, we genetically added recombinant human lysozyme (rhLZ) to sow milk by somatic cell nuclear transfer and investigated whether the presence of recombinant human lysozyme can influence intestinal microbiota and mophology in sucking pigs. We generated transgenic cloned pigs and the first-generation hybrids (F1) produced high levels of rhLZ in milk. The average concentration of rhLZ was 116.34±24.46 mg/L in the milk of F1 sows, which was 1500-fold higher than that of the native pig lysozyme. In vitro, it was demonstrated that rhLZ in milk of transgenic pigs had enzyme levels at 92,272±26,413 U/mL. In a feeding experiment, a total of 40 newborn piglets were nursed by four transgenic sows and four sibling non-transgenic sows (F1), with five piglets per gilt. The piglets were allowed to nurse for 21 days and the sow milk was the only source of nutrition for the piglets. All piglets were slaughtered on postnatal day 22. Six types of bacteria were cultured and analyzed to detect the impact of rhLZ on gut microbiota. The number of Escherichia coli in the duodenum of piglets reared by transgenic sows was significantly decreased (p<0.001) and their villus height to crypt depth ratio in the intestine were increased due to the significant decrease of crypt depth in the duodenum, jejunum, and ileum (p<0.001). Together, we successfully generated rhLZ transgenic cloned pigs and elevated lysozyme level in nuring piglets. The results of the feeding experiments demonstrated that rhLZ-enhanced milk can inhibit the growth of E. coli in the duodenum and positively influence intestinal morphology without adversely affecting weight gain or piglet growth.

High prevalence and widespread distribution of multi-resistant Escherichia coli isolates in pigs and poultry in China

Escherichia coli play an important ecological role within resistant bacteria populations, and can be used as a bio-indicator of antimicrobial resistance. The aim of the present study was to use this feature of E. coli to investigate the prevalence of antimicrobial resistance and the degree of cross-species transmission of bacteria in pigs and poultry in China. A total of 592 E. coli strains, isolated from pigs and poultry (healthy and diseased animals), were tested for resistance to 22 antimicrobials representing eight antimicrobial drug types. E. coli isolates had high rates of resistance to ampicillin (99.5%), doxycycline (95.6%), tetracycline (93.4%), trimethoprim-sulfamethoxazole (74.3%), amoxicillin (65.1%), streptomycin (54.7%), and chloramphenicol (50.2%). Resistance to cephalosporins, quinolones, and aminoglycosides was also quite prevalent. The majority (81%) of isolates demonstrated multi-antimicrobial resistance, most commonly to 5-6 different antimicrobial types. One isolate was resistant to all 22 antimicrobials. Twenty-two cultures exhibiting multi-antimicrobial resistance were analysed by pulsed-field gel electrophoresis (PFGE) to assess their distribution between farms. Three distinct PFGE types were identified, indicating inter-farm transmission of multi-antimicrobial resistant bacteria. The study confirmed the presence and transmission of multi-antimicrobial-resistant E. coli strains amongst pigs and poultry in China and highlights the urgent need for appropriate monitoring programmes.