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A collection of 250 enterococci isolated from various food-stuffs were used to investigate seven virulence determinants and the microbial susceptibility of eight antibiotics. Species-specific PCR revealed the presence of E. faecalis (127 isolates), E. faecium (77 isolates), E. casseliflavus (21 isolates), E. mundtii (19 isolates) and E. durans (6 isolates). Multiplex PCR for virulence factors showed that out of the 250 isolates tested, 221 carried one or more virulence-encoding genes. Beta-haemolytic activity was also evident in enterococcal species other than E. faecalis and E. faecium. Species other than E. faecalis and E. faecium isolated from food may also be virulent. Antimicrobial susceptibility was tested using the disk diffusion method. It showed that out of 250 isolates, 114 were resistant to cephalothin and 94 to ofloxacin. Lower antibiotic resistance was seen with ampicillin, chloramphenicol, gentamicin and teicoplanin. None of the isolates was found to be resistant to vancomycin. The results of this study show that food can play an important role in the spread of virulent enterococci through the food chain.

We monitored the presence of Listeria monocytogenes in environmental sources and evaluated phenotypic and molecular characteristics of the isolates recovered. L. monocytogenes was isolated in 12 of the 107 samples from wild and farm environments, and from vegetation. Most isolates (83.3%) were of serotype 1/2a and the remainder (2) were of serotype 4b. All 12 isolates were susceptible to the whole range of antimicrobials tested. These 12 strains were carriers of the virulence genes prfA, hlyA, actA, plcA, plcB, inlA, inlB, inlC, and inlJ. The detection of the inlA gene in 4 strains using the PCR-RFLP suggests the potential of some of these strains to penetrate into epithelial cells of the intestinal barrier. Macrorestriction analysis also confirmed clonal identity of some environmental isolates with food and human isolates. These results indicate that the external environment is a source of potentially pathogenic strains of L. monocytogenes.

A total of 116 Escherichia (E.) coli isolates isolated from neonatal diarrhoeic piglets were serogrouped and tested for the presence of virulence genes for fimbrial and non-fimbrial adhesins, intimin, and enterotoxins. Pulsed-field gel electrophoresis (PFGE) pulsotypes were also analyzed within O149 enterotoxigenic E. coli (ETEC) isolates. In total, Sixty eight (58.6%) isolates were serotyped. Among them, forty three (63.2%) belonged to 12 serogroups in the descending order: O149, O8, O157, O101, O60, O9, O117, O127, O138, O167, O27 and O97. The predominant pathotype was ETEC (68, 58.6%) which is closely associated with F4 (37, 31.9%) and LT:STb:EAST1 (23, 19.8%) out of the isolates harbouring at least one gene for toxin and/or fimbria. Among non-fimbrial adhesins, porcine attaching and effacing-associated factor (paa) was closely associated with F4-positive isolates (64.7%) rather than F18-positive isolates (5.9%). Adhesion involved in diffuse adherence (AIDA) was only detected in 3 isolates. No eae-positive isolates were detected. The PFGE pattern of 15 O149 isolates was grouped into 12 pulsotypes at 88% similarity level. The results show a wide variety of distinct restriction patterns though all belonged to the same serogroup O149. It is believed that a broad array of O serogroup and virulence genes are associated with neonatal diarrhoea in Korea.

In Central Asia, stem rust (Puccinia graminis f.sp. tritici) causes considerable damage, especially during growing seasons with high rainfall. Ug99 is a race of stem rust that is virulent to the majority of wheat varieties. To develop disease-free germplasm, wheat material was screened using the predominant stem rust races of Kazakhstan and tested in two nurseries, CIMMYT-Turkey and the Plant Breeding Station at Njoro, Kenya. A total of 11 pathotypes of P. graminis f.sp. tritici were identified in Kazakhstan from the stem rust samples collected in 2008-2009. In particular, pathotypes TDT/H, TPS/H, TTH/K, TKH/R, TKT/C and TFK/R were highly virulent. Of the 170 advanced lines of wheat, 21 CIMMYT lines resistant to 5 aggressive Kazakhstani pathotypes of P. graminis were identified. A high level of resistance was observed in 11 wheat cultivars and advanced lines: Taza, E-19, E-99, E-102, E-572, E-796, E-809 (Kazakhstan), Ekinchi (Azerbaijan), Dostlik, Ulugbek 600 (Uzbekistan) and Umanka (Russia). Based on data obtained from Turkey-CIMMYT and the Plant Breeding Station Njoro, out of 13 tested entries, 6 wheat breeding lines which were resistant to both stem and yellow rust and 10 wheat lines which showed high and moderate levels of resistance to Ug99 were selected. Using the sequence tagged site molecular marker Sr24No.12, associated with Sr24/Lr24, seven wheat entries resistant to stem rust were identified.

Faecal samples from 230 diarrhoeic and healthy calves aged 0-6 weeks, from 100 farms in Austria, were examined between October 2004 and February 2005 for the presence of bacteria, especially Shiga toxin-producing Escherichia coli (STEC), viruses and parasites. Escherichia coli was detected in 17% of all the faecal samples and was more prevalent in healthy calves. However, E. coli F5 was identified only in one calf without diarrhoea. Overall, 35 out of the 230 (15.2%) samples analyzed carried the Shiga toxin gene: stx1, stx2 or both stx1 and stx2 in their faeces. Nevertheless, out of 39 pathogenic E. coli positive samples observed, only two carried the Shiga toxin genes: stx1 in one diarrhoeic calf, and both stx1 and stx2 in one healthy calf; eaeA and Ehly genes were detected more frequently in the strains from diarrhoeic calves (57.1% and 50.0%, respectively). Clostridium perfringens was detected in twenty-one samples, the most prevalent toxin type of C. perfringens was found to be type A (76.2%). Other bacteria such as Klebsiella spp. and Proteus spp. were present in 1.3% and 0.4% of all samples. Salmonella spp. was not detected. The detection rates of other enteropathogens were 25.7% bovine coronavirus, 11.7% Cryptosporidium spp., 10.4% Eimeria spp., 9.1% group A rotavirus and Giardia spp. 6.1%. We demonstrated the presence of the STEC virulence genes in healthy and diarrhoeic Austrian calves but the importance of the virulence factors of STEC (stx1, stx2, eae and Ehly) in calf diarrhoea and systemic disease is not well defined.

The pathogenicity of entomopathogenic fungi, Beauveria bassiana, Metarhizum anisopilae and Lecanicillium lecanii, was evaluated against adults of the olive fly Bactrocera oleae under laboratory conditions by two ways, contact bioassays and oral bioassays. The results showed that oral bioassays caused higher mortality after four treatments than the used contact bioassays. Moreover, the virulence of L. lecanii was higher than the virulence of B. bassiana and M. anisopilae in both ways of experiment. Lethal time (LT50) was shorter in oral bioassays than in contact bioassays in all treatments. It was 14.67, 8.30 and 5.43 days for B. bassiana, M. anisopilae and L. lecanii with oral treatment, while it was 16.6, 26.07 and 12.59 days for B. bassiana, M. anisopilae and L. lecanii, respectively, with contact treatment. The slope values were 2.41, 2.55 and 2.37 for contact bioassays and 1.64, 1.69 and 1.61 for oral bioassays of B. bassiana, M. anisopilae and L. lecanii, respectively. The mortality response to the interaction between B. bassiana and M. anisopilae was synergistic while the interaction between B. bassiana + L. lecanii and M. anisopilae + L. lecanii showed an antagonistic response.

Virulence frequencies to powdery mildew resistances in winter barley cultivars mostly registered in the Czech Republic were studied in 2007 and 2008. Random samples of the air populations originating from winter and spring barley fields were obtained by means of a mobile version of a jet spore sampler. Conidia were sampled by driving across the Czech Republic. In total, 349 isolates were studied and 17 differentials were used. The virulence frequencies to specific resistances of given cultivars showed wide range - from 0% to 100%. Nine differentials were used to distinguish 134 pathotypes, of which 32 representing 63.9% of isolates were detected in both years. Pathotype 773 which broke down the resistance of eight differentials was the most abundant. In 2008, lower virulence frequencies to all differentials, and thus lower population complexity were determined, which may be caused by different regional origins of the isolates examined.

In the growing seasons from 2003 to 2008, 547 isolates of Phytophthora infestans from five regions in the Czech Republic were collected and examined for their sensitivity to the active ingredients (metalaxyl, dimethomorph and propamocarb-HCl) of frequently used fungicides. The response of the isolates to each of these substances was examined using the in vitro amended-agar method; in 352 of these isolates, the sensitivity to metalaxyl was also assessed by the floating leaf-disc assay. The majority of the isolates were sensitive (89.8%) to metalaxyl. Resistant isolates were found only in two of the sample years (2003 and 2008); they represented 58% of the samples in 2003 and only 29% in 2008. Four isolates from 2004 were found to be intermediate for their level of resistance. All the isolates that were tested were sensitive to dimethomorph and propamocarb-HCl; these particular substances completely suppressed mycelial growth at 1 microg a.i. per mL.

Virulences to powdery mildew resistances in barley cultivars mostly carrying unknown resistances were determined in 2009 and 2010. Random spore samples of the airborne pathogen populations originating from winter and spring barley fields were obtained by means of a mobile version of a jet spore sampler by travelling across the Czech Republic. In total 301 isolates were studied, 55 differentials carrying mostly unknown resistances were used and 80 pathotypes were found, of which 26 representing 73.1% of isolates were detected in both years. Virulence frequencies showed a wide range from 0% to 100%. Complexity of the 2010 population slightly increased, mostly due to increasing frequencies of virulence to new resistances, whereas the complexity of virulences to resistances in most other differentials decreased. Pathotype 00027 was the most abundant (10.0%). Diversity of the 2010 population considerably increased due to changes in virulence frequencies.

The resistant reaction to tomato spotted wilt virus (TSWV) was found to be determined by a single dominant gene in three Capsicum chinense Jacq. accessions ('PI 152225', 'PI 159236','7204'). Allelism studies indicated that all C. chinense lines bear the same allele located at the Tsw locus. All the inoculated plants in the allelism tests displayed a resistant hypersensitive phenotype characterized by necrotic local lesions followed by abscission of the inoculated organ. However, a small proportion of them showed late systemic infection. Nine TSWV isolates obtained from these individual plants with systemic symptoms were backinoculated to the three resistant parents. All isolates were able to infect systemically all the resistant accessions without inducing local necrotic lesions. Serological analysis confirmed that these nine viral isolates belong to the TSWV species (serogroup I). Consequently, the susceptible plants in the allelism tests could not be interpreted as possessing a recombinant genotype because of the virulence change in the viral strain. Hobbs et al. (1994) already reported the existence of TSWV pathotypes overcoming the resistance of C. chinense resistant accessions. Practical consequences for pepper breeding associated with the emergence of these resistance-breaking isolates are discussed.