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The aim of this paper is to describe a new variant of Janthinobacterium lividum - ROICE173, isolated from Antarctic snow, and to investigate the antimicrobial effect of the crude bacterial extract against 200 multi-drug resistant (MDR) bacteria of both clinical and environmental origin, displaying various antibiotic resistance patterns. ROICE173 is extremotolerant, grows at high pH (5.5–9.5), in high salinity (3%) and in the presence of different xenobiotic compounds and various antibiotics. The best violacein yield (4.59 ± 0.78 mg·g−1 wet biomass) was obtained at 22 °C, on R2 broth supplemented with 1% glycerol. When the crude extract was tested for antimicrobial activity, a clear bactericidal effect was observed on 79 strains (40%), a bacteriostatic effect on 25 strains (12%) and no effect in the case of 96 strains (48%). A very good inhibitory effect was noticed against numerous MRSA, MSSA, Enterococci, and Enterobacteriaceae isolates. For several environmental E. coli strains, the bactericidal effect was encountered at a violacein concentration below of what was previously reported. A different effect (bacteriostatic vs. bactericidal) was observed in the case of Enterobacteriaceae isolated from raw vs. treated wastewater, suggesting that the wastewater treatment process may influence the susceptibility of MDR bacteria to violacein containing bacterial extracts.

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Biofouling occurs without exception in all water systems, with undesirable effects such as biocorrosion and deterioration of water quality. Drinking water associated biofilms represent a potential risk to human health by harbouring pathogenic or toxin-releasing microorganisms. This is the first study investigating the attached microbiota, with potential threat to human health, in a public water system in Romania. The presence and the seasonal variation of viable faecal indicators and opportunistic pathogens were investigated within naturally developed biofilms in a drinking water treatment plant. Bacterial frequencies were correlated with microbial loads in biofilms as well as with physical and chemical characteristics of biofilms and raw water. The biofilms assessed in the current study proved to be extremely active microbial consortia. High bacterial numbers were recovered by cultivation, including Pseudomonas aeruginosa, Escherichia coli, Aeromonas hydrophila, intestinal enterococci and Clostridium perfringens. There were no Legionella spp. detected in any biofilm sample. Emergence of opportunistic pathogens in biofilms was not significantly affected by the surface material, but by the treatment process. Implementation of a water safety plan encompassing measures to prevent microbial contamination and to control biofouling would be appropriate.

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Introduction Members of the family Enterobacteriaceae are commonly identified in the clinical laboratory, being responsible for a substantial range of infections. This study aimed to investigate phenotypic and genotypic resistance traits in pathogenic Enterobacteriaceae isolated from outpatients in Cluj-Napoca, Romania. Methods Pathogenic Enterobacteriaceae were isolated from urinary tract infections, wound infections and persistent diarrhea in a private laboratory from Cluj-Napoca, Romania. Bacterial strains were biochemically identified and subjected to antimicrobial susceptibility testing by disk diffusion. The carriage of antibiotic resistance genes and of class 1 integron were assessed by PCR. Results E. coli and Enterobacter spp. were the most prevalent pathogens. High levels of resistance were observed against folate pathway inhibitors (74%), fluoroquinolones (49%) and penicillins (44%). The incidence of carbapenem resistance was 3%. The strains displaying phenotypic resistance were able to produce β-lactamase enzymes encoded by bla TEM , bla TEM-1 , bla SHV-1 and bla CTX-M , aminoglycoside modifying enzymes due to the carriage of aac(3)-IIIa, aac(6')-II and aac(6')-Ie-aph(2"), to possess fluoroquinolones resistance due to qnrS DNA gyrase protection proteins and resistance to folate pathway inhibitors due to dihydropteroate synthases encoded by sul1, sul2 and sul3 genes. The high frequency of intI1 integrase was associated to sulphonamide resistance (r=0.48; p<0.001) and also to fluoroquinolone resistance (r=0.27; p=0.011), but no significant associations in the co-occurrence of specific antibiotic resistance genes and intI1 were found in pathogenic Enterobacteriaceae. Conclusions An important proportion of pathogenic Enterobacteriaceae were multidrug resistant, due to a wide diversity of mechanisms encoding genetic resistance.