Diversity and antibiotic resistance profiles of Listeria monocytogenes serogroups in different food products from Transylvania Region, Central Romania

The aim of this study was to assess the presence and antimicrobial susceptibility profile of the molecularly serogrouped Listeria monocytogenes isolates in different animal origin food products, collected from a county situated in the historical region of Transylvania, Central Romania. A total of 7.7% (17/221) of the screened samples were positive for L. monocytogenes , with an isolation frequency of 6.2% (8/130) in the ready-to-eat products (i.e., sausages, ham and smoked specialties), 12.8% (6/47) in raw meat (i.e., minced pork, pork organs and snails), and 6.8% (3/44) in dairy (i.e., assortment of cheeses) samples. The identified L. monocytogenes serogroups were: 1/2a-3a (47.1%), 4b-4d-4e (29.4%), 1/2c-3c (11.8%), and 4a-4c (11.8%), respectively. All isolates were resistant to benzylpenicillin and fusidic acid. Resistance was also detected towards oxacillin (88.2%), fosfomycin (82.4%), clindamycin (76.5%), imipenem (52.9%), ciprofloxacin (41.2%), rifampicin (41.2%), trimethoprim – sulfamethoxazole (29.4%) and tetracycline (29.4%). On the other hand, all isolates proved susceptible to gentamicin, moxifloxacin, teicoplanin, vancomycin, tigecycline, erythromycin and linezolid. All tested strains exhibited multidrug resistance, resulting in the expression of a total of 12 resistance profiles. These findings extend the understanding about the spread of an important pathogen in Romanian food products, highlighting a substantial public health issue and medical concern, especially for consumers with a compromised health status.

Identification and Isolation Pattern of Globisporangium spp. from a Sanionia Moss Colony in Ny-Ålesund, Spitsbergen Is., Norway from 2006 to 2018

Globisporangium spp. are soil-inhabiting oomycetes distributed worldwide, including in polar regions. Some species of the genus are known as important plant pathogens. This study aimed to clarify the species construction of Globisporangium spp. and their long-term isolation pattern in Sanionia moss in Ny-Ålesund, Spitsbergen Is., Norway. Globisporangium spp. were isolated at two-year intervals between 2006 and 2018 at a Sanionia moss colony, Ny-Ålesund, Spitsbergen Is., Norway. The isolates were obtained by using three agar media and were identified based on sequences of the rDNA-ITS region and cultural characteristics. Most of the Globisporangium isolates obtained during the survey were identified into six species. All six species were grown at 0 °C on an agar plate and used to infect Sanionia moss at 4 and/or 10 °C under an in vitro inoculation test. The total isolation frequency of Globisporangium gradually decreased throughout the survey period. The isolation frequency varied among the six species, and four of the species that showed a high frequency in 2006 were rarely isolated after 2016. The results suggested that Globisporangium inhabiting Sanionia moss in Ny-Ålesund has a unique composition of species and that most of the species reduced their population over the recent decade.

Impact of Thermotherapy and Short-Term Storage on Quercus robur L. Acorn Mycobiota and Germination

When natural regeneration of Quercus robur stands is hampered by an insufficient acorn yield, human assisted sowing of acorns collected in non-affected stands and stored for some period of time is performed. To inhibit the development of fungi and acorn deterioration during storage, thermotherapy is usually applied by submerging acorns for 2.5 h in water heated to 41 °C. This research aimed to test the effect of four thermotherapy treatments of different durations and/or applied temperatures as well as short-term storage at −1 °C or 3 °C on acorn internal mycobiota and germination. Fungal presence in cotyledons was analyzed in 450 acorns by isolation of mycelia on artificial media, followed by a DNA-based identification. Germination of 2000 acorns was monitored in an open field trial. Thermotherapy significantly decreased fungal diversity, while storage at 3 °C increased the isolation frequency of several fungi, mainly Penicillium spp. The most frequently isolated fungi did not show a negative impact on acorn germination after short-term storage. The study confirmed the efficiency of thermotherapy in the eradication of a part of acorn internal mycobiota, but also its effect on the proliferation of fast-colonizing fungi during storage. However, the latter showed to be more stimulated by storage conditions, specifically by storage at 3 °C.

Prevalence of the Genes Associated with Biofilm and Toxins Synthesis amongst the Pseudomonas aeruginosa Clinical Strains

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with an increasing isolation frequency in nosocomial outbreaks. The hypothesis tested was whether carbapenem-resistant P. aeruginosa strains display an altered carriage of the virulence factor genes, depending on the type of carbapenem resistance. The aim of the study was to investigate, by PCR, the frequency of 10 chosen virulence factors genes (phzM, phzS, exoT, exoY, exoU, toxA, exoS, algD, pilA and pilB) and the genotype distribution in 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. P. aeruginosa genes involved in phenazine dyes and exoenzyme T synthesis were noted with the highest frequency (100%). Fimbriae-encoding genes were detected with the lowest incidence: 15.9% and 4.7% for pilin A and B, respectively. The differences observed between the exoS gene prevalence amongst the carbapenemase-positive and the carbapenemase-negative strains and the pilA gene prevalence amongst the strains of different origins were statistically significant. Virulence genes’ prevalence and the genotype distribution vary amongst P. aeruginosa strains resistant to carbapenems, especially in terms of their carbapenemase synthesis ability and the strain origin.

Dynamic analysis and experiment of QZS system with nonlinear hysteretic damping

Nonlinear Quasi-zero-stiffness (QZS) vibration isolation systems with linear damping cannot lead to displacement isolation with different excitation levels. In this study, a QZS system with nonlinear hysteretic damping was investigated. The Duffing-Ueda equation with a coupling nonlinear parameter 𝜂 was proposed to describe the dynamic motion of the QZS system. By using the harmonic balance method (HBM), the primary and secondary harmonic responses were obtained and verified by numerical simulations. The results indicated that nonlinear damping can guarantee a bounded response for different excitation levels. The one-third subharmonic response was found to affect the isolation frequency range even when the primary response was stable. To evaluate the performance of the QZS system, the effective isolation frequency Ω𝑒 and maximum transmissibility 𝑇𝑝 were proposed to represent the vibration isolation range and isolation effect, respectively. By discussing the effect of 𝜂 on Ω𝑒 and 𝑇𝑝, the conditions to avoid nonlinear phenomena and improve the isolation performance are provided. A prototype of the QZS system was then constructed for vibration tests, which verified the theoretical analysis.

Monitoring of microscopic fungi community in selected bee products

Honey is a remarkably complex food with a valued place in the human diet. An important indicator of its quality is the presence of microorganisms. This study aimed to monitor the mycological quality of 27 samples of Slovak kinds of honey and honey products with the addition of differently processed blueberries, cranberries, and red currants. Yeast and filamentous microscopic fungi were monitored using the plate dilution method. A total of 21 samples (78%) were positive for the presence of yeasts and 14 samples (52%) were positive for the filamentous microscopic fungi occurrence. In 6 samples (22%) no presence of microscopic fungi was found at all. The highest number of yeasts (3.07 log CFU.g-1) was recorded in one flower honey sample and in other samples, yeast counts did not exceed 3 log CFU.g-1. The highest numbers of filamentous micromycetes (2.39 and 2.44 log CFU.g-1) were recorded in 2 honeydew honey samples. Overall, the following genera have been identified: Alternaria, Arthrinium, Aspergillus (including previously named as Eurotium), Aureobasidium, Cladosporium, Mucor, Penicillium, and Stemphilium. Penicillium spp. were recorded with the highest isolation frequency (41%). Aspergillus species were isolated from 19% of honey samples. In the honey with fruit addition, the yeasts in a range of 1.00 – 3.09 log CFU.g-1 and the filamentous microscopic fungi in a range of 1.00 – 1.39 log CFU.g-1 were found. The study showed that cranberries were the most appropriate addition from a mycological point of view. Dried and lyophilized forms of tested fruits were the most suitable. Except for honey with frozen currants and honey with fresh cranberries, all final products had a water activity below 0.610 and appeared to be stable.

Dark Septate Endophytic Fungi Associated with Sugarcane Plants Cultivated in São Paulo, Brazil

Dark septate endophytes (DSEs) constitute a polyphyletic group within the Ascomycota, with global distribution and a wide range of host plant species. The present study evaluated the diversity of DSE in sugarcane roots of the varieties RB867515, RB966928, and RB92579, and four varieties of not commercialized energy cane. A total of 16 DSE strains were isolated, mostly from the varieties RB966928 and RB867515, with six and five isolates, respectively. Just one of the four energy cane varieties had fungi with DSE appearance. The analyses of the DNA sequences from the internal transcribed spacer (ITS) and the large subunit (LSU), in association with the micromorphology of the isolates, allowed the differentiation of the 16 isolates in at least five species, within the families Periconiaceae, Pleosporaceae, Lentitheciaceae, Vibrisseaceae, and Apiosporaceae and the orders Pleosporales, Helotiales, and Xylariales. The order Pleosporales represented 80% of the isolates, and the species Periconia macrospinosa, with six isolates, accounted for the highest isolation frequency. The results confirm the natural occurrence of the DSE symbiosis in sugarcane varieties and the generalist character of these fungi as some of the detected species have already been reported associated with other host plants, ecosystems, and regions of the world.

Eight-year trends in the relative isolation frequency and antimicrobial susceptibility among bloodstream isolates from Greek hospitals: data from the Greek Electronic System for the Surveillance of Antimicrobial Resistance – WHONET-Greece, 2010 to 2017

Background Antimicrobial resistance (AMR) changes over time and continuous monitoring provides insight on trends to inform both empirical treatment and public health action. Aims To survey trends in relative isolation frequency (RIF) and AMR among key bloodstream pathogens using data from the Greek Electronic System for the Surveillance of AMR (WHONET-Greece). Methods This observational study looked into routine susceptibility data of 50,488 blood culture isolates from hospitalised patients in 25 tertiary hospitals, participating in the WHONET-Greece for trends over time between January 2010 and December 2017. Only the first isolate per species from each patient was included. Hospital wards and intensive care units (ICUs) were analysed separately. Results During the study, the RIF of Acinetobacter baumannii increased in wards, as did the proportion of A. baumannii isolates, which were non-susceptible to most antibiotics in both wards and ICUs. Coincidently, Klebsiella pneumoniae RIF declined while the respective rates of non-susceptible isolates to carbapenems and gentamicin increased. Pseudomonas aeruginosa RIF remained stable but decreasing proportions of non-susceptible isolates to all studied antibiotics, except imipenem were observed. Escherichia coli RIF increased as did the proportion of isolates non-susceptible to third-generation cephalosporins, carbapenems and fluoroquinolones. Concerning Staphylococcus aureus, a decline in the percentage of meticillin resistant isolates in ICUs was found, while the percentages of Enterococcus faecium isolates with non-susceptibility to vancomycin stayed stable. Conclusions Recognising these trends over time is important, since the epidemiology of AMR is complex, involving different ‘bug and drug’ combinations. This should be taken into consideration to control AMR.