Antibiotic resistance marker genes as environmental pollutants in GMO-pristine agricultural soils in Austria.

Antibiotic resistance genes may be considered as environmental pollutants if anthropogenic emission and manipulations increase their prevalence above usually occurring background levels. The prevalence of aph(3')-IIa/nptII and aph(3')-IIIa/nptIII - frequent marker genes in plant biotechnology conferring resistance to certain aminoglycosides - was determined in Austrian soils from 100 maize and potato fields not yet exposed to but eligible for GMO crop cultivation. Total soil DNA extracts were analysed by nptII/nptIII-specific TaqMan real time PCR. Of all fields 6% were positive for nptII (median: 150 copies/g soil; range: 31-856) and 85% for nptIII (1190 copies/g soil; 13-61600). The copy-number deduced prevalence of nptIII carriers was 14-fold higher compared to nptII. Of the cultivable kanamycin-resistant soil bacteria 1.8% (95% confidence interval: 0-3.3%) were positive for nptIII, none for nptII (0-0.8%). The nptII-load of the studied soils was low rendering nptII a typical candidate as environmental pollutant upon anthropogenic release into these ecosystems.

Prevalence of the aminoglycoside phosphotransferase genes aph(3')-IIIa and aph(3')-IIa in Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica and Staphylococcus aureus isolates in Austria.

The aminoglycoside phosphotransferase aph(3')-IIa primarily inactivates kanamycin and neomycin, whilst aph(3')-IIIa also inactivates amikacin. The aim of this study was to determine the frequency of both resistance genes in major human pathogens to obtain their baseline prevalence in the gene pool of these bacterial populations in Austria. In total, 10 541 Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica and Staphylococcus aureus isolates were collected representatively without selection bias between 2008 and 2011. Isolates were analysed by aph(3')-IIIa/nptIII- and aph(3')-IIa/nptII-specific TaqMan real-time PCR. For positive strains, MICs using Etests were performed and resistance gene sequences were determined. The overall prevalence of aph(3')-IIIa/nptIII was 1.62 % (95 % confidence interval: 1.38-1.88 %). In Escherichia coli, enterococci, Staphylococcus aureus, P. aeruginosa and Salmonella spp., the aph(3')-IIIa/nptIII prevalence was 0.47 % (0-1.47 %), 37.53 % (32.84-42.40 %), 2.90 % (1.51-5.02 %), 0 % (0-0.32 %) and 0 % (0-0.037 %), respectively. Eleven of a total of 169 carriers showed single-nucleotide polymorphisms in the resistance allele. The overall prevalence of aph(3')-IIa/nptII was 0.0096 % (0-0.046 %). Escherichia coli (0-0.70 %), enterococci (0-0.75 %), Staphylococcus aureus (0-0.73 %) and P. aeruginosa (0-0.32 %) did not carry aph(3')-IIa. A single Salmonella isolate was positive, resulting in an aph(3')-IIa prevalence of 0.013 % (0-0.058 %). aph(3')-IIIa/nptIII carriers were moderately prevalent in the strains tested except for in enterococci, which appeared to be an important reservoir for aph(3')-IIIa. aph(3')-IIa/nptII genes were detected at clinically irrelevant frequencies and played no significant role in the aminoglycoside resistance gene pool during the observation period.

A Two-Years' Survey on the Prevalence of Tuberculosis Caused by Mycobacterium caprae in Red Deer (Cervus elaphus) in the Tyrol, Austria.

A survey of 143 hunter-harvested red deer for tuberculosis was conducted in an Alpine area in Western Austria over two subsequent years. There, single tuberculosis cases caused by Mycobacterium caprae had been detected in cattle and red deer over the preceding decade. The area under investigation covered approximately 500 km(2), divided into five different hunting plots. Lymph nodes of red deer were examined grossly and microscopically for typical tuberculosis-like lesions and additionally by microbiological culturing. Executing a detailed hunting plan, nine M. caprae isolates were obtained. Six out of nine originated from one single hunting plot with the highest estimated prevalence of tuberculosis, that is, 23.1%. All isolates were genotyped by mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) typing of 24 standard loci plus VNTR 1982. All nine isolates belonged to a single cluster termed "Lechtal" which had been found in cattle and red deer in the region, demonstrating a remarkable dominance and stability over ten years. This is the first report on a systematic prospective study investigating the prevalence and strain variability of M. caprae infection in red deer in Austria and in the Alpine countries.

[Evaluation of four commercial RT-qPCR test kits for detection of Bluetongue virus RNA]. / Evaluierung von vier kommerziellen RT-qPCR Testkits zum Nachweis von Bluetongue Virus RNA.

Since 2006, the occurrence of bluetongue in Northwest- and Central Europe has lead to extensive financial losses. For first-line laboratory diagnosis, reverse transcription real-time PCR (RT-qPCR) has been used increasingly, necessitating careful evaluation of all applied methods by the performing laboratory. In the course of an internal validation, four commercially available BTV RT-qPCR kits and two published reference methods were compared. Clear differences regarding reaction kinetics, analytical as well as diagnostic sensitivity and specificity were observed. Furthermore, test kits were not equally suitable for testing samples from a selection of BTV-susceptible host species. Only two commercial kits were in all examined parameters equal to, or superior than, the more demanding reference methods and thus represent a possible alternative to using published methods for BTV RT-qPCR screening.