New Insight into Genotypic and Phenotypic Relatedness of Staphylococcus aureus Strains from Human Infections or Animal Reservoirs

Cilj ovog rada bio je ispitati učinkovitost ekstrakcije bioaktivnih spojeva iz listova koprive (Urtica dioica L.) primjenom ubrzane ekstrakcije otapalima pri povišenom tlaku (ASE). Uz etanol kao ekstrakcijsko otapalo, ispitivani su sljedeći parametri ekstrakcije: (i) statičko vrijeme ekstrakcije (5 i 10 min); (ii) broj ciklusa ekstrakcije (1, 2, 3 i 4 ciklusa); te (iii) temperatura (20 i 50 °C). U dobivenim ekstraktima provedeno je spektrofotometrijsko određivanje ukupnih fenola, karotenoida te klorofila a i b. Rezultati istraživanja su pokazali kako sva tri varirana parametra značano utječu na masene udjele ispitivanih spojeva (p ≤ 0,01). Maseni udjeli ukupnih fenola određeni su u rasponu 106,44 do 739,72 mg 100 g-1, klorofila a od 116,44 do 490,42 mg 100 g-1, klorofila b od 44,88 do 166,85 mg g-1 te karotenoida od 36,62 do 133,99 mg 100 g-1. Najveći prinosi dobiveni su pri sljedećim uvjetima ekstrakcije: ukupni fenoli, karotenoidi i klorofil a pri temperaturi 50 °C i 4 ekstrakcijska ciklusa od 10 min; klorofil b pri temperaturi ekstrakcije od 50 °C, 3 ekstrakcijska ciklusa od 10 min.The aim of this study was to investigate the extraction efficiency of the bioactive compounds from stinging nettle (Urtica dioica L.) leaves by using Accelerated Solvent Extraction (ASE). Ethanol was used as the extraction solvent and the following extraction parameters were investigated: (i) static extraction time (5 and 10 min); (ii) number of extraction cycles (1, 2, 3 and 4 cycles); and (iii) temperature (20 and 50 °C). All extracts were spectrophotometrically evaluated in terms of total phenols, carotenoids and chlorophylls a and b. The results of the research have shown that all extraction parameters significantly affected the concetrations of the investigated compounds (p≤0,01). Mass fractions of total phenols ranged from 106,44 to 739,72 mg GAE 100 g-1, chlorophyll a from 116,44 to 490,42 mg 100 g-1, chlorophyll b from 44,88 to 166,85 mg 100 g-1 and carotenoids from 36,62 to 133,99 mg 100 g-1. The highest yields were obtained under the following extraction conditions: extraction temperature of 50 °C and four 10 minute cycles for total phenols, carotenoids and chlorophyll a and extraction temperature of 50 °C and three 10 minutes cycles for chlorophyll b

Antibiotic resistance and virulence of Escherichia coli strains isolated from animal rendering plant

Abstract Processing of animal carcasses and other animal wastes in rendering plants is a significant source of antibiotic resistant microorganisms. The main goal of this study was to investigate the resistance to 18 antibacterial agents including β-lactams, fluoroquinolones, colistin and virulence factors (iss, tsh, cvaC, iutA, papC, kps and ibeA genes) in 88 Escherichia coli strains isolated from a rendering plant over 1 year period. ESBL (Extended-spectrum beta-lactamases) and plasmid-mediated Amp were screened by interpretative reading of MIC. ESBL phenotype was detected in 20.4% of samples and high level of resistance to fluoroquinolone was found in 27.2% of strains. Cephalosporinase CTX-M1, cephamycinase CMY-2, integrase 1 and transposon 3 genes were detected by PCR. Furthermore, there were found three CMY-2 producing E. coli with O25b-ST131, resistant to the high level of enrofloxacin and containing the gene encoding the ferric aerobactin receptor (iutA). One enrofloxacin resistant E. coli strain possessed iss, ibeA, kps and papC virulence genes also with CMY-2, integrase1 and Tn3. ST131 E. coli with CMY-2 has a zoonotic potential and presents a serious health risk to humans

New Insight on Antibiotic Resistance and Virulence of Escherichia coli from Municipal and Animal Wastewater

Antibiotic resistance of the indicator microorganism Escherichia coli was investigated in isolates from samples collected during the course of one year from two wastewater treatment plants treating municipal and animal wastes in Slovakia, respectively. The genes of antibiotic resistance and virulence factors in selected resistant E. coli isolates were described. A high percentage of the isolates from municipal and animal wastewater were resistant to ampicillin, streptomycin, tetracycline, ceftiofur, ceftriaxone, and enrofloxacin. In the selected E. coli isolates, we detected the following phenotypes: ESBL (20.4% in animal wastewater; 7.7% in municipal wastewater), multidrug-resistant (17% of animal and 32% of municipal isolates), high resistance to quinolones (25% of animal and 48% of municipal samples), and CTX-M (7.9% of animal and 17.3% of municipal isolates). We confirmed an integro-mediated antibiotic resistance in 13 E. coli strains from municipal and animal wastewater samples, of which the Tn3 gene and virulence genes cvaC, iutA, iss, ibeA, kps, and papC were detected in six isolates. One of the strains of pathogenic E. coli from the animal wastewater contained genes ibeA with papC, iss, kpsII, Int1, Tn3, and Cit. In addition, one blaIMP gene was found in the municipal wastewater sample. This emphasises the importance of using the appropriate treatment methods to reduce the counts of antibiotic-resistant microorganisms in wastewater effluent