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Laboratory Standards Institute guidelines ( CLSI, 2018 ). The antimicrobial agents (Rosco, Taastrup, Denmark) used in this study included ampicillin (10 µg), cefepime (30 µg), trimethoprim/sulfamethoxazole (1.25 µg + 23.75 µg), amoxicillin/clavulanic acid (20
) (Oxoid, CTO412B, 30 µg), amoxicillin-clavulanic acid (AMC; Oxoid, CT0223B, 30 µg), meropenem (MEM) (Oxoid, CT0774B, 10 µg), and ampicillin (AMP; Oxoid, CTOOO3B, 10 µg) antibiotic discs were used. The plates were incubated at 35 ± 2 °C for 18 ± 2 h. The
In this study, two bacilli strains, namely TN51 and TN69, previously isolated from Thua Nao, a Thai traditional fermented soybean, were studied in terms of their phenotypic and biochemical properties. Initially, both strains were subjected to morphological determination and a series of biochemical tests. Both were Gram-positive, endosporeforming bacilli. Based on 16S rRNA gene sequence analysis, the identities of strains TN51 and TN69 were confirmed as Bacillus subtilis and B. cereus, respectively. In addition, these two strains were also assessed for their antibiogram profiles. It was found that both strains were susceptible to chloramphenicol, erythromycin, kanamycin, tetracycline, and vancomycin and resistant to ampicillin and intermediately susceptible to bacitracin.
The objective of this study was to examine antibacterial, antifungal and antiviral properties of selected Phlomis species (Lamiaceae) growing in Turkey. The petroleum ether and methanol extracts of the seven species, namely P. armeniaca Willd., P. bourgaei Boiss., P. leucophracta P.H. Davis & Hub.-Mor., P. lunariifolia Sibth. & Sm., P. lycia D. Don, P. pungens Willd. var. pungens , and P. pungens var. hirta Velen. were tested against Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus, Bacillus subtilis , and Enterococcus faecalis for their antibacterial activity using ampicillin and oflaxocin as references. Antifungal activity of the same extracts was determined against Candida albicans using microdilution method with ketocanazole as reference. Both DNA virus Herpes simplex type-1 (HSV-1) and RNA virus Parainfluenza (PI-3) were employed for antiviral assessment of the Phlomis extracts using Madin-Darby Bovine Kidney and Vero cell lines in which acyclovir for HSV-1 and oseltamivir for PI-3 were employed as reference drugs. Although both the petroleum ether and methanol extracts seemed to exert similar antibacterial activity, the methanolic extracts were observed to be more active against S. aureus and E. faecalis . On the other hand, methanolic extract of P. pungens var. pungens possessed notable antiviral activity against both type of viruses.
L. monocytogenes poses a serious threat to public health, since most cases of listeriosis are connected with eating contaminated food. L. monocytogenes is often detected both in fresh and frozen vegetables.
The aim of this study was to evaluate the antibiotic susceptibility and ability to form biofilm of L. monocytogenes strains isolated from frozen vegetable mixtures in Poland.
Ninetynine genetically different strains were found among 100 isolates of L. monocytogenes. Among the 99 strains, 80 (80.8%) were susceptible to all tested antibiotics. Nineteen (19.2%) strains were resistant to one or more antibiotics. From this group of L. monocytogenes strains, most strains were resistant to erythromycin (16; 16,1%), penicillin (15; 15.1%), meropenem (12; 12.1%), cotrimoxazole (12; 12.1%), and ampicillin (3; 3.1%). According to the obtained results, differences in intensity of biofilm, both between those isolated in successive years and in the particular year, were observed. Performed analysis showed statistically insignificant faint negative correlation (r=–0.088) between the number of antibiotics to which strains were resistant and the intensity of biofilm formation by them.
Food contamination with L. monocytogenes poses a threat to consumers, therefore it is necessary to monitor their antibiotic susceptibility, ability to form biofilm, and genetic similarity, in order to evaluate the strains persistence time in plant.
Honey is the most important bee product. There are many secondary metabolites, carbohydrates, enzymes, and vitamins in honey, thus, honey has antimicrobial activity. In this study, in vitro antimicrobial activity of forty-two honey and eight propolis ethanolic extracts (PEE) were investigated against 16 microorganisms. Total phenolic content ranged between 20.00–124.10 mg GAE/100 g and 103–232 mg GAE/g for honey and raw propolis samples, respectively. Pine and oak honeydew honeys had higher antimicrobial activity than four different grades of Manuka Honeys up to 18 mm minimum inhibition zone diameters. The ethanolic propolis extracts showed much higher antimicrobial activity than the honey samples. Fungi species were inhibited by the propolis samples. Helicobacter pylorii (H. pylorii) was the most sensitive, whereas Streptococcus agalactiae was the most resistant bacteria among the studied microorganisms. Brazilian and Zonguldak propolis had the closest antimicrobial activity to ampicillin, streptomycin, and fluconazole. It can be concluded that both honey and propolis could be used in preservative and complementary medicine.
The aims of this study were to isolate LAB from Thai plant-derived foods and beverages and to examine in vitro probiotic properties including b-glucosidase enzyme activity. Lactobacillus plantarum SC 359 selected from Thai pickled soybean was significantly (P<0.05) the best to perform β-glucosidase enzyme activity (0.396 U ml−1 at 18 h of incubation) out of the 227 tested strains. The strain survived in 0.30% (w/v) bile salt and had high tolerance to acidic pH with survival rates at a 2 h period of 72.24%, 85.52%, 92.64%, and 93.38% at pH 2.0, 3.0, 4.0, and 5.0, respectively. The SC 359 strain showed proteolytic and lipolytic activities. Moreover, the selected strain displayed strong antagonistic activities against Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Salmonella Typhi, Shigella sonnei and Candida albicans ATCC 90028. The strain was susceptible to ampicillin, chloramphenicol, erythromycin, gentamicin, kanamycin, rifampicin, streptomycin, tetracycline, and vancomycin. In addition, the selected strain significantly inhibited the adherence to Caco-2 cells of E. coli, S. Typhi and Sh. sonnei (P<0.05) by 33.50 to 73.37%. The strain could obstruct the adherences of pathogens by elimination, competition, and displacement with pathogen adherences 33.62–53.92%, 26.63–59.23%, and 49.41–66.50%, respectively. Based on the results, the selected strain could be applied as functional starter for Thai fermented plant-derived foods and beverages.
were used in the study. Erythromycin, ampicillin/sulbactam, rifampicin, amikacin, and fluconazole antibiotic discs were used to compare the antimicrobial effects of the extracts used. 2.4 Antioxidant assays The free radical scavenging activities of the
), clindamycin (2 µg), vancomycin (30 µg), ampicillin (30 µg), chloramphenicol (30 µg), tetracycline (30 µg), cefotixin (30 µg), rifampicin (5 µg), and oxacillin (1 µg) were used. The breakpoints of Staphylococcus and Enterococcus species resistance were used
using distilled water at concentrations 800–12.5 μg mL −1 and tested against microorganisms. Fluconazole, Amphotericin B (yeasts), Amikacin, Ampicillin, and Ciprofloxacin (bacteria) were used as reference drugs ( Sevindik, 2020 ). 2.4 Antiproliferative