Dissemination of VanA-Type Enterococcus faecium Isolates in Hungary.

Although vanA carrying Enterococcus faecium human clinical isolates have been rarely found in Hungary before 2012, they have been detected in continuously increasing numbers since then. To identify factors associated with their dissemination, we investigated the clonal relatedness and plasmids of 30 vanA carrying E. faecium isolates originating from different Hungarian healthcare institutions from 2012 to 2014. Molecular typing of the isolates (n = 30) was performed with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, Tn1546 polymerase chain reaction mapping, plasmid restriction fragment length polymorphism analysis, and sequencing. A single Tn1546 variant was detected in all of the isolates. It harbored IS1251 in the vanS-vanH intergenic region, had an entire deletion of the transposase gene and a partial deletion of the resolvase gene, and was located on a pRUM-like plasmid. Based on PFGE, the isolates could be grouped into 13 pulsotypes. Representative strains of these pulsotypes belonged to ST17, ST18, ST80, ST117, and ST203, which are known to be part of the hospital-adapted clades. The increase in the number of vanA carrying E. faecium clinical isolates in Hungary could be explained by the dissemination of pRUM-like vancomycin resistance plasmids in hospital-adapted clonal lineages.

First description of a rifampicin-resistant Neisseria meningitidis serogroup Y strain causing recurrent invasive meningococcal disease in Hungary.

A Hungarian soldier previously immunized against Neisseria meningitidis by quadrivalent polysaccharide vaccine was twice infected with meningococci within six weeks. The patient was treated with ceftriaxone during both episodes and he successfully recovered. His close contacts received rifampicin prophylaxis. An investigation was performed to characterize the genetic background of the pathogens to ascertain if the recurrent invasive meningococcal disease was caused by the same strain and to find out the reason for reinfection. Both meningococci belonged to the fine type Y:P1.5-2,10-1:F4-1:ST-23. This is the first description of the Europe-wide prevalent N. meningitidis serogroup Y in Hungary. In the first episode, we found wild-type rpoB allele in the non-culturable sample implying the susceptibility to rifampicin. The culturable isolate from the second episode proved resistant to rifampicin and had a point mutation in the rpoB gene. The rifampicin resistance might have evolved during the prophylactic treatment of contacts. Previous immunization of the patient with polysaccharide vaccine was ineffective due to his immunodeficiency, thus immunization with conjugate vaccine was proposed. We have proposed the implementation of centralized rifampicin susceptibility testing of N. meningitidis strains within a defined time frame to intervene and administer appropriate prophylaxis to close contacts.

A simple and novel volumetric method to metre low gas flows from laboratory-scale bioreactors and its application on laboratory sludge digesters.

A novel, cheap and easy to use method has been developed to measure low gas yields in bioreactors, based on the principle of bubble counting via digital imaging techniques and pattern recognition. No external hardware control is required for the measurements, and the device can be turned into a multichannel tool without further detector accessories. The method proved to perform outstandingly according to the testing and calibrating measurements against standard gas flow and revealed a short periodicity in the gas yields of two parallel laboratory-scale mesophilic biogas reactors providing well analysable data about them. For exact characterization of the oscillation, the data were converted into Morell wavelet spectra, which showed that every feeding period had a characteristic and similarly shaped wavelet profile, thereby this rhythm must have had an immanent source in the community metabolism, and it was not an artefact.

DGGE and T-RFLP analysis of bacterial succession during mushroom compost production and sequence-aided T-RFLP profile of mature compost.

The amount of button mushroom (Agaricus bisporus) harvested from compost is largely affected by the microbial processes taking place during composting and the microbes inhabiting the mature compost. In this study, the microbial changes during the stages of this specific composting process were monitored, and the dominant bacteria of the mature compost were identified to reveal the microbiological background of the favorable properties of the heat-treated phase II mushroom compost. 16S ribosomal deoxyribonucleic acid (rDNA)-based denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) molecular fingerprinting methods were used to track the succession of microbial communities in summer and winter composting cycles. DNA from individual DGGE bands were reamplified and subjected to sequence analysis. Principal component analysis of fingerprints of the composting processes showed intensive changes in bacterial community during the 22-day procedure. Peak temperature samples grouped together and were dominated by Thermus thermophilus. Mature compost patterns were almost identical by both methods (DGGE, T-RFLP). To get an in-depth analysis of the mature compost bacterial community, the sequence data from cultivation of the bacteria and cloning of environmental 16S rDNA were uniquely coupled with the output of the environmental T-RFLP fingerprints (sequence-aided T-RFLP). This method revealed the dominance of a supposedly cellulose-degrading consortium composed of phylotypes related to Pseudoxanthomonas, Thermobifida, and Thermomonospora.

Characterisation of community structure of bacteria in parallel mesophilic and thermophilic pilot scale anaerobe sludge digesters.

The aim of the present work was to compare the microbial communities of a mesophilic and a thermophilic pilot scale anaerobe sludge digester. For studying the communities cultivation independent chemotaxonomical methods (RQ and PLFA analyses) and T-RFLP were applied. Microbial communities of the mesophilic and thermophilic pilot digesters showed considerable differences, both concerning the species present, and their abundance. A Methanosarcina sp. dominated the thermophilic, while a Methanosaeta sp. the mesophilic digester among Archaea. Species diversity of Bacteria was reduced in the thermophilic digester. Based on the quinone patterns in both digesters the dominance of sulphate reducing respiratory bacteria could be detected. The PLFA profiles of the digester communities were similar though in minor components characteristic differences were shown. Level of branched chain fatty acids is slightly lower in the thermophilic digester that reports less Gram positive bacteria. The relative ratio of fatty acids characteristic to Enterobacteriaceae, Bacteroidetes and Clostridia shows differences between the two digesters: their importance generally decreased under thermophilic conditions. The sulphate reducer marker (15:1 and 17:1) fatty acids are present in low quantity in both digesters.