CTX-M-producing Escherichia coli in pigs from a Czech farm during production cycle.

We evaluated the prevalence and epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates in pigs during production cycle on a Czech farm with the history of previous use of ceftiofur. ESBL-producing E. coli isolates were obtained from rectal swabs from pigs of different age groups (suckling piglets, weaned piglets, growers and sows). Collected samples were directly cultivated on MacConkey agar with cefotaxime (2 mg l-1 ), whereas intestinal swabs of slaughtered pigs and surface swabs from pig carcasses were also pre-enriched in buffered peptone water without antimicrobials before the cultivation. Clonal relationship of selected isolates was determined by XbaI pulse-field gel electrophoresis and multi-locus sequence typing. The transferability of plasmids carrying blaCTX-M genes was tested by conjugation experiments. From all examined samples, 141 (43·7%, n = 323) were positive for ESBL-producing E. coli. All ESBL-producing isolates showed resistance to multiple antimicrobials and were positive for blaCTX-M genes. The blaCTX-M-1 was carried by conjugative IncN/ST1 plasmids (c. 40-45 kb) while the blaCTX-M-15 was located on conjugative F plasmids with F:18:A5:B1 formula (c. 165 kb). This study demonstrated the persistence of CTX-M-positive E. coli isolates 2 months after banner of ceftiofur usage and indicated possible risk of transmission of these isolates to humans via the food chain.

Antibiotic resistance and virulence factors in mesophilic Aeromonas spp. from Czech carp fisheries.

AIMS: The aim of this study was to determine phenotypic and genotypic resistance, virulence and clonal relationship of aeromonads and related species isolated from Czech carp fisheries. METHODS AND RESULTS: Forty-nine isolates obtained from a total of 154 fish from three breeding facilities were species identified using matrix-assisted laser desorption/ionization time of flight and the sequencing of the rpoB housekeeping gene. Most Aeromonas isolates were identified as Aeromonas veronii (94%, n = 34). Susceptibility to six antibiotics (oxytetracycline, flumequine, florfenicol, sulphamethoxazole/trimethoprim, enrofloxacin and oxolinic acid) was tested using the disc diffusion method. The presence of resistance genes and virulence factors was verified by PCR and sequencing, and the clonal relationship was analysed using pulsed-field gel electrophoresis (PFGE). Phenotypic resistance to one or more antimicrobials was found in 32 isolates (65%, n = 49). Resistance to oxytetracycline was the most common (41%) and associated mainly with the presence of tet(E) gene, while the percentage of isolates resistant to florfenicol was low (2%). Isolates carried one to five of the tested virulence factors and showed high diversity of PFGE profiles. CONCLUSIONS: Since the highest percentage of antimicrobial resistance in aeromonads was found for oxytetracycline and the lowest percentage for florfenicol, it is suggested that florfenicol could be an adequate treatment alternative in carp fisheries. SIGNIFICANCE AND IMPACT OF THE STUDY: Increasing resistance of aeromonads to commonly used antimicrobials has become an emerging problem in fisheries. This study was conducted in relation to the practical needs to identify a suitable antibiotic as an alternative to oxytetracycline.

Evaluation of the use of recombinant Bhlp29.7 in immunoblotting with pig serum as a means to identify herds infected with Brachyspira hyodysenteriae.

AIMS: Aim of the study is to evaluate the use of recombinant Bhlp29.7 in immunoblotting with sera as a means to detect pig herds infected with Brachyspira hyodysenteriae. METHODS AND RESULTS: Sera samples from 789 sows and rectal swabs from 838 pigs of various categories on 22 farms of different size (median 450 animals), production type and history of swine dysentery (SD) were examined. Sera from 378 sows from farms with previous SD history were examined via immunoblotting. Specific antibodies were detected in 79 of these (20.9%). Examination of 411 serum samples from sows and gilts taken on 11 farms without previous history of SD detected specific antibodies in 13 sows and gilts (3.2%). These 13, however, had come from farms where the presence of B. hyodysenteriae was confirmed or SD status was not known. Seroprevalence in herds with previous SD history ranged from 2.5 to 35.7%. B. hyodysenteriae was confirmed on six (27.3%) of 22 monitored farms. CONCLUSIONS: Immunoblotting using recombinant antigen Bhlp29.7 in conjunction with culturing B. hyodysenteriae proved to be a valuable tool for detecting swine herds latently infected with B. hyodysenteriae. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of immunoblotting with recombinant Bhlp29.7 should prove to be a useful adjunct to detecting herds with SD, and hence, it will assist in controlling this important disease.

Extended-spectrum beta-lactamase-producing Escherichia coli in turkey meat production farms in the Czech Republic: national survey reveals widespread isolates with bla(SHV-12) genes on IncFII plasmids.

AIM: The occurrence and epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in the environment of turkey farms in the Czech Republic were studied. METHODS AND RESULTS: Extended-spectrum beta-lactamase-producing E. coli isolates were found on 8 (20%) of 40 turkey farms surveyed. A total of 200 environmental smears were examined, and a total of 25 ESBL-producing E. coli were isolated. These isolates were analysed using XbaI pulsed-field gel electrophoresis and divided into nine pulsotypes. Most of the isolates harboured the gene bla(SHV-12) on a 40-kb plasmid of the IncFII group with an identical EcoRV restriction profile. Indistinguishable or clonally related SHV-12-producing isolates belonging to the same pulsotypes were found at some unrelated farms. CONCLUSIONS: Widespread occurrence of ESBL-producing E. coli isolates with bla(SHV-12) carried on IncFII plasmids in meat production flocks in the Czech Republic was demonstrated. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate vertical transmission of ESBL-producing E. coli within the turkey production pyramid. The study shows the risk of multiresistant ESBL-producing bacteria and antibiotic-resistance genes being transmitted to humans via the food chain.

Antimicrobial-resistant faecal Escherichia coli in wild mammals in central Europe: multiresistant Escherichia coli producing extended-spectrum beta-lactamases in wild boars.

AIMS: To determine the presence of antibiotic-resistant faecal Escherichia coli in populations of wild mammals in the Czech Republic and Slovakia. METHODS AND RESULTS: Rectal swabs or faeces collected during 2006-2008 from wild mammals were spread on MacConkey agar and MacConkey agar containing 2 mg l(-1) of cefotaxime. From plates with positive growth, one isolate was recovered and identified as E. coli. Susceptibility to 12 antibiotics was tested using the disk diffusion method. Resistance genes, class 1 and 2 integrons and gene cassettes were detected in resistant isolates by polymerase chain reaction (PCR). Extended-spectrum beta-lactamases (ESBL) were further characterized by DNA sequencing, macrorestriction profiling and determination of plasmid sizes. Plasmid DNA was subjected to EcoRV digestion, transferability by conjugation and incompatibility grouping by multiplex PCR. The prevalence of resistant isolates was 2% in small terrestrial mammals (rodents and insectivores, n(E. coli) = 242), 12% in wild ruminants and foxes (n(E. coli) = 42), while no resistant isolates were detected in brown bears (n(E. coli) = 16). In wild boars (Sus scrofa) (n(E. coli) = 290), the prevalence of resistant isolates was 6%. Class 1 and 2 integrons with various gene cassettes were recorded in resistant isolates. From wild boars, five (2%, n(rectal smears) = 293) multiresistant isolates producing ESBL were recovered: one isolate with bla(CTX-M-1) + bla(TEM-1), three with bla(CTX-M-1) and one with bla(TEM-52b). The bla(CTX-M-1) genes were carried on approx. 90 kb IncI1 conjugative plasmids. CONCLUSIONS: Antibiotic-resistant E. coli occurred in populations of wild mammals in various prevalences. SIGNIFICANCE AND IMPACT OF THE STUDY: Wild mammals are reservoirs of antibiotic-resistant E. coli including ESBL-producing strains which were found in wild boars.

Antibiotic resistance in faecal bacteria (Escherichia coli, Enterococcus spp.) in feral pigeons.

AIMS: To determine the presence of antibiotic-resistant faecal Escherichia coli and Enterococcus spp. in feral pigeons (Columba livia forma domestica) in the Czech Republic. METHODS AND RESULTS: Cloacal swabs of feral pigeons collected in the city of Brno in 2006 were cultivated for antibiotic-resistant E. coli. Resistance genes, class 1 and 2 integrons, and gene cassettes were detected in resistant isolates by polymerase chain reaction (PCR). The samples were also cultivated for enterococci. Species status of enterococci isolates was determined using repetitive extragenic palindromic-PCR. Resistance genes were detected in resistant enterococci by PCR. E. coli isolates were found in 203 of 247 pigeon samples. Antibiotic resistance was recorded in three (1·5%, n(E. coli) =203) isolates. Using agar containing ciprofloxacin, 12 (5%, n(samples) =247) E. coli strains resistant to ciprofloxacin were isolated. No ESBL-producing E. coli isolates were detected. A total of 143 enterococci were isolated: Ent. faecalis (36 isolates), Ent. faecium (27), Ent. durans (19), Ent. hirae (17), Ent. mundtii (17), Ent. gallinarum (12), Ent. casseliflavus (12) and Ent. columbae (3). Resistance to one to four antibiotics was detected in 45 (31%) isolates. Resistances were determined by tetK, tetL, tetM, tetO, aac(6')aph(2''), ant(4')-Ia, aph(3')-IIIa, ermB, pbp5, vanA and vanC1 genes. CONCLUSIONS: Antibiotic-resistant E. coli and Enterococcus spp. occurred in feral pigeons in various prevalences. SIGNIFICANCE AND IMPACT OF THE STUDY: Feral pigeon should be considered a risk species for spreading in the environment antimicrobial resistant E. coli and enterococci.

Antibiotic-resistant Salmonella and Escherichia coli isolates with integrons and extended-spectrum beta-lactamases in surface water and sympatric black-headed gulls.

AIM: To examine surface water from a pond in the northeastern part of the Czech Republic and young black-headed gulls (Larus ridibundus) nesting on the same pond for the presence of antibiotic-resistant Salmonella and Escherichia coli. METHODS AND RESULTS: A total of 16% (n = 87) of water and 24% (n = 216) of gull samples yielded Salmonella. Salmonella Enteritidis PT8 and PT4 were the most prevalent. Antibiotic resistance was found in 12% (n = 14) of water and 28% (n = 51) of gull salmonellae. Escherichia coli were found in 83 (95%) and 213 (99%) of pond water and gull samples, respectively. Totals of 18% (n = 83) of water and 28% (n = 213) of gull E. coli isolates were resistant to antimicrobial agents tested. Class 1 integrons were found in 21% (n = 14) of water and 15% (n = 60) of gull antibiotic-resistant E. coli isolates. Class 2 integrons and extended-spectrum beta-lactamase-producing E. coli isolates (with bla(CTX-M-1), bla(CTX-M-15)-like, bla(SHV-2) and bla(SHV-12)) were found in 13% (eight positive, n = 60 gull-resistant E. coli isolates) and 3% (seven positive, n = 216 gull E. coli isolates) of gull isolates, respectively. Antibiotic-resistant E. coli isolates with identical pulsed field gel electrophoresis (PFGE) patterns were found in either gulls or water, but not both. Salmonellae of the same serotype and PFGE profile were found in both gulls and water. CONCLUSION: A high prevalence of antibiotic-resistant salmonellae and E. coli were found in both pond water and in sympatric black-headed gulls. SIGNIFICANCE AND IMPACT OF THE STUDY: Intensive contamination of pond surface water by antibiotic-resistant E. coli and salmonellae was documented. Black-headed gulls were identified as important reservoirs of antibiotic-resistant salmonellae and E. coli, including extended-spectrum beta-lactamase-producing isolates.

Survey of Shiga toxigenic Escherichia coli O157 and drug-resistant coliform bacteria from in-line milk filters on dairy farms in the Czech Republic.

AIMS: To determine the occurrence of Shiga toxin-producing Escherichia coli (STEC) O157 and coliform bacteria isolates resistant to antimicrobial agents in dairy herds by examining milk filters and to analyse the influence of management factors and antibiotic use on antimicrobial resistance. METHODS AND RESULTS: A total of 192 in-line milk filters were sampled on 192 dairy farms in the Czech Republic. Information on feeding, husbandry, production, and antibiotic therapy were obtained by questionnaire. The milk filters were cultured for STEC O157 and coliform bacteria. All recovered isolates were examined for antimicrobial susceptibility and presence of antimicrobial-resistance genes. STEC O157 was detected in four (2%) of the filters. Resistant nonpathogenic E. coli and coliform bacteria isolates with specific genes were detected in 44 (23%) of the filters. CONCLUSIONS: The study demonstrated a high prevalence of resistant coliform bacteria in milk filters obtained on Czech dairy farms. SIGNIFICANCE AND IMPACT OF THE STUDY: The occurrence of resistant coliform bacteria in milk filters was significantly higher among isolates from farms where antibiotic therapy against mastitis was employed during the dry period (P < 0.05).

Antimicrobial resistant Escherichia coli isolates in cattle and house sparrows on two Czech dairy farms.

Rectal smears of calves, cows and young bulls, as well as cloacal smears of house sparrows (Passer domesticus), from farms at the villages of Sumice and Troskotovice, Czech Republic, were examined for E. coli resistant to 12 antimicrobials. The resistant isolates were tested for antimicrobial-resistance genes and integrons. Totals of 40% (n=183), 3% (n=95), 0% (n=33), and 9% (n=54) of Escherichia coli isolates from calves, cows, young bulls and house sparrows, respectively, were antimicrobial resistant. The following genes were identified in cattle E. coli isolates: tetA, tetB (isolates resistant to tetracycline), bla(TEM) (beta-lactams), strA, aadA (streptomycin), sul1, sul2 (sulphonamides), and cat, floR (chloramphenicol). Seven of 16 antimicrobial-resistant calf isolates from the Sumice farm possessed class 1 integrons with the aadA1 gene cassette integrated, 1 kb in size. On the Troskotovice farm, eight of 57 antimicrobial-resistant calf isolates possessed class 1 integrons. Integrons of 1.5kb with the dhfr1- aadA1 gene cassette were found in four isolates, followed by a 1kb integron with the aadA1 gene found in three isolates, and a 1.7kb integron with the dhfr17-aadA5 gene cassette and the phenotype ASSuTSxtNaCipCCfG. The prevalence of resistant E. coli in calves compared to adult cattle was much higher and probably was influenced by oral antimicrobial usage in calves, feeding with milk and colostrum from treated cows, as well as mechanisms unrelated to antimicrobial drug selection. Although house sparrows lived together with the cattle and came into contact with cattle waste on the farm, they were not infected by resistant E. coli isolates with the same characteristics as those found in cattle.

Prevalence of selected enteropathogenic bacteria in Hungarian finishing pigs.

The aim of this study was to obtain prevalence estimates about the most important enteropathogenic bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Brachyspira pilosicoli, Salmonella enterica and Clostridium perfringens A and C in Hungarian farrow-to-finish pig herds. A total of 31 herds were selected, from where six pooled faecal samples, each containing three individual rectal faecal samples were collected from fattening pigs of 5-6 months of age. All 186 samples were examined by polymerase chain reaction (PCR) for the presence of the pathogens mentioned above. Lawsonia intracellularis was found in 29 herds (93.55%) and in 108 samples (58.06%); B. hyodysenteriae in 14 herds (45.16%) and in 23 samples (12.37%); B. pilosicoli in 19 herds (61.29%) and in 53 samples (28.49%); S. enterica in 17 herds (54.83%) and in 40 samples (21.50%). We detected the presence of C. perfringens A in 19 herds (61.29%) and in 46 samples (24.73%), while C. perfringens C was found in 8 herds (25.81%) and in 11 samples (5.91%). All examined herds were infected with one or more of these agents. Herds with diarrhoea in the mid- to late finishing phase had almost 10 times higher prevalence of B. hyodysenteriae than herds without such a history.

Assessment of diagnostics and antimicrobial susceptibility testing of Brachyspira species using a ring test.

There is no ring test for quality assessment available in Europe for diagnostics and antimicrobial susceptibility testing of the fastidious, anaerobic bacteria of the genus Brachyspira. Therefore, an international ring test for Brachyspira spp. was performed once a year during 2002-2004. Two sets of coded samples were prepared and distributed on each occasion. One set comprised six swabs dipped in pig faeces spiked with Brachyspira spp. intended for diagnostics. The other set comprised two pure strains intended only for susceptibility testing. All methods used were in-house methods. The species used were Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira innocens, Brachyspira murdochii and Brachyspira intermedia. In most cases, the correct Brachyspira spp. were detected. However, the results showed that Brachyspira spp. could be difficult to identify, especially if two Brachyspira spp. were mixed or if the concentration of Brachyspira in faeces was low. Additionally, some laboratories reported Brachyspira growth in control samples that were not seeded with any spirochaetes. The lowest detection level was 10(2) bacteria/ml faeces for both B. hyodysenteriae and B. pilosicoli. The susceptibility tests performed showed that disc diffusion was not recommendable for Brachyspira spp. Extended antimicrobial dilution series gave most congruent results. The diversity of the results highlights the importance of ring tests for a high quality of diagnostics and antimicrobial susceptibility tests for Brachyspira spp. This is the first ring test described for Brachyspira spp.

Prevalence, characterization and antibiotic resistance of Salmonella isolates in large corvid species of europe and north America between 2010 and 2013.

It is well understood that Salmonella is carried by animals and in majority of cases as asymptomatic hosts. Surveillance efforts have focused on the role of agriculture and contamination points along the food chain as the main source of human infection; however, very little attention has been paid to the contribution of wildlife in the dissemination of Salmonella and what effect anthropogenic sources have on the circulation of antibiotic resistant Salmonella serovars in wildlife species. A purposive survey was taken of large corvids roosting yearly between November and March in Europe and North America. Two thousand and seven hundred and seventy-eight corvid faecal specimens from 11 countries were submitted for Salmonella spp. culture testing. Presumptive positive isolates were further serotyped, susceptibility tested and analysed for antibiotic resistance genes. Overall, 1.40% (39/2778) (CI = 1.01, 1.90) of samples were positive for Salmonella spp. Salmonella Enteritidis was the most prevalent serovar followed by S. Infantis, S. Montevideo and S. Typhimurium. No significant difference (P > 0.05) was found in the proportion of Salmonella recovered in Europe versus North America. The most variability of serovars within a site was in Kansas, USA with five different serovars recovered. European sites were significantly more likely to yield Salmonella resistant to more than one antibiotic (OR 71.5, P < 0.001, CI = 3.77, 1358) than North American sites, where no resistance was found. Resistance to nalidixic acid, a quinolone, was recovered in nine isolates from four serovars in four different sites across Europe. Large corvids contribute to the transmission and dissemination of Salmonella and resistance genes between human and animal populations and across great distances. This information adds to the knowledge base of zoonotic pathogen prevalence and antibiotic resistance ecology in wild birds.

[Occurrence of Salmonellae in the laughing gull (Larus ridibundus)]. / Výskyt salmonel u racka chechtavého (Larus ridibundus).

In 1984-1994 black-headed gulls (Larus ridibundus) from various localities in the Czech Republic were examined to assess the incidence of salmonellae. A total of 99 eggs from two nest colonies were examined. No salmonellae were detected. In examinations of 740 young birds from three colonies the total prevalence was 19.3%. In full grown gulls (number of examined birds 189) from five localities the total prevalence of salmonellae was 4.2%. In water specimens near the nest colonies, other habitats of the gulls and from soil specimens from one nest colony (throughout the year) salmonellae of the same serotypes as in gulls were isolated. The young birds contaminate surface waters with salmonellae. The importance of adult birds as a source of infection is much smaller. Only for the young of aquatic birds (fowl or free living) gulls could be an important source of salmonella infections. The presence of salmonellae in gulls is due to contamination of surface waters and the surroundings of nest colonies with salmonellae.

[Antibiotic resistance in strains of Salmonella typhimurium and S. enteritidis isolated from poultry in the Czech Republic 1991-1992]. / Antibiotická rezistence u kmenu Salmonella typhimurium a S. enteritidis izolovaných z hrabavé drubeze v Ceské republice v letech 1991-1992.

Antibiotic resistance has been monitored in 293 strains of S. typhimurium and 260 strains of S. enteritidis isolated from poultry in Czech Republic in the years 1991 and 1992. Ninety per cent of all salmonella isolations examined by disc diffusion method (Bauer et al., 1966) were sensitive to all 8 antimicrobials (chloramphenicol, neomycin, tetracycline, streptomycin, colistin, ampicillin, kanamycin, sulfisoxazol) used for testing. The strains of S. typhimurium were more resistant than S. enteritidis strains, as seen from the percentage of resistant strains, 17.4% and 1.2% respectively. Thirty-two (62.7%) out of 51 resistant strains were multiresistant. The percentage of resistance in S. typhimurium strains was as follows: sulfisoxazol (12.3%), streptomycin (11.3%), tetracycline (4.4%) and chloramphenicol (1.7%).

The isolation of salmonellae from poultry carcasses and equipment in the poultry processing plant by means of two procedures.

A total of 235 samples (swabs, rinse and organs) from freshly dressed broiler carcasses and from equipment of poultry processing plant were examined for the presence of salmonellae by means of motility enrichment on modified semisolid Rappaport medium (SAM) and of a conventional cultural procedure using Rappaport-Vassiliadis broth (R-VB) as selective enrichment. In 61 samples (26%), Salmonella was isolated by means of one or both procedures. The highest contamination with Salmonella was found in the rinse of broiler carcasses (35.5%), followed by swabs of equipment (32.0%), tissues of organs (31.0%) and swabs of carcasses (19.7%). Twelve different serotypes and 65 strains of salmonellae were detected. S. saint paul and S. enteritidis were the most frequent serotypes. Statistical analysis showed that there was no significant difference between the procedures.

[Characteristics of the plasmid profile of inositol- and rhamnose- negative strains of Salmonella typhimurium]. / Charakteristika plazmidového profilu inozitol a rhamnóza negativních kmenu Salmonella typhimurium.

S. typhimurium isolates obtained during a large outbreak of human salmonellosis associated with smoked mackerels in the Czech Republic as well as strains of S. typhimurium isolated from black headed gull (Larus ridibundus) were examined following biotyping, phage typing, plasmid profiling and restriction endonuclease analysis (Eco RI, Hind III and Bam HI) of plasmid DNA. The epidemic strain of S. typhimurium and two isolates from environment of nesting colony black-headed gull were meso-inositol and L-rhamnose negative, phage type 141. The isolates from human and environment of nesting colony were found to share the same plasmid profile and REA.

[Findings of Yersinia in slaughter pigs, synantropic animals and workers in meat products in a defined region]. / Prubezné nálezy yersinií u jatecných prasat, synantropních zvírat a zamestnancu zivocisné výroby v definovaném územním okrsku.

In 15 selected stocks in the Strakonice district, 507 slaughter pigs, 708 small terrestric mammals and 110 free-living birds were examined in a two-year period (1986-1987) to study the occurrence of carriers of yersiniae and their elimination. Rectal smears from 243 persons working in livestock production were examined in the same way. Standard bacteriological methods, recent examination procedures (Aulisio et al., 1980; Aldová, 1981) and a diagnostic antiserum (03 IMUNA Sarisské Michalany) were used for the examination. The following results were obtained: In pigs: 1. yersiniae were detected in 65 cases (12.8%); of this, in 31 cases they occurred in the tonsils, in 35 cases in ileum, and twice in the ileocaecal lymph nodes. 2. Epidemiologically significant Y. enterocolitica 4;03 was detected in 28 cases (5.5%); of this, 22 times in the tonsils, 7 times in ileum, and once in the ileocaecal lymph nodes. 3. The seasonal nature of the occurrence of yersiniae was confirmed in 1986, with maxima in winter-spring, but in 1987 their occurrence declined substantially to less than a quarter. In the small mammals, yersiniae were detected 28 times (4%); of this, 7 times in common field mouse, 11 times in common vole, 5 times in house mouse, twice in shrew, once in Apodemus flavicollis, and once in Apodemus sp. 2. Y. enterocolitica 4;03 was detected twice (0.26%), both cases in the house mouse. Other results: 1. In all the 110 free-living birds the examination for yersiniae had a negative result; 2. in the rectal smears of 243 persons employed in livestock production, yersiniae were identified twice (0.8%)--in one case Y. enterocolitica 1, in the other Y. enterocolitica biovars 1 and 2.

Characterisation of multiresistant Brachyspira hyodysenteriae isolates from Czech pig farms.

The aim of the present study was to evaluate the importance of clonal spread of Brachyspira hyodysenteriae resistant to pleuromutilins (tiamulin, valnemulin) on farms in the Czech Republic. Agar dilution method and macrorestriction fragment profile analysis by pulsed field gel electrophoresis were used to characterise 35 B hyodysenteriae isolates that were obtained from clinical cases of swine dysentery on 32 farms between 2000 and 2005. Most isolates showed multiple resistances to tiamulin, valnemulin, tylosin and lincomycin. A total of six pulsotypes were detected in these multiresistant isolates. An analysis of epidemiological data showed that multiresistant B hyodysenteriae isolates were more often detected on fattening farms (59 per cent), compared with farms with other types of production. Furthermore, it was found that multiresistant B hyodysenteriae clones were most frequently selected on farms with endemic incidence of swine dysentery. This finding was confirmed by the characterisation of 21 B hyodysenteriae isolates obtained from three large-scale operations in seven consecutive years.

The selection of single-chain Fv antibody fragments specific to Bhlp 29.7 protein of Brachyspira hyodysenteriae.

Single-chain antibodies (scFv) specific to Brachyspira hyodysenteriae were isolated from a phagemid library. Recombinant Bhlp 29.7 protein was used for scFv selection and individual clones were tested by ELISA and immunofluorescent test; four unique clones were isolated. One of selected clones was able to bind specifically B. hyodysenteriae in ELISA and immunofluorescence test. This is the first report of species-specific recombinant antibodies against B. hyodysenteriae.