Susceptibility to Bacteriocins of Multiresistant, mecA Gene Possessing Staphylococcus pseudintermedius Strains from Lesions on Dogs in Vojvodina (Serbia).

Aims: Staphylococci are considered commensal organisms; however, they can also cause diseases in animals. The species Staphylococcus pseudintermedius was originally isolated from the nares and anal mucosa of healthy dogs; nowadays, the incidence of methicillin-resistant S. pseudintermedius strains in dogs has increased, and this species has also become the most common cause of canine skin lesions. S. pseudintermedius were tested for their susceptibility to bacteriocins to show the potential of bacteriocins to eliminate/reduce S. pseudintermedius as a causative agent. Material and Methods: In this study, S. pseudintermedius were isolated from skin lesions on dogs of various breeds and ages in the Vojvodina region (Serbia) in the framework of our international co-operation. Results: S. pseudintermedius strains were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and the species allocation was confirmed by genotypization and corroborated using phenotyping tests. The strains were multiresistant, involving methicillin-resistance. In addition, the mecA gene was detected in S. pseudintermedius strains, confirming the presence of a genetic feature for methicillin resistance. S. pseudintermedius strains produced large amounts of the enzymes alkaline phosphatase and acid phosphatase; they were low-grade biofilm forming (0.1 ≤ A570 < 1.0), except S. pseudintermedius SPs1. All strains were susceptible to gallidermin (inhibition activity up to 204,800 arbitrary unit [AU]/mL); however, they were mostly resistant to enterocins. However, biofilm-forming S. pseudintermedius SPs1 was susceptible to enterocins (200 AU/mL). Conclusion: Establishing the susceptibility of multiresistant and mecA gene-possessing S. pseudintermedius strains to gallidermin is an innovative, original result; it provides a new opportunity for preventing/eliminating infection caused by those agents.

Fluoroquinolone-resistant and extended-spectrum beta-lactamase producing Escherichia coli isolates from free-living wild animals.

During the hunting season 2013-2014, fecal samples collected from hare, roe deer, deer and wild boars were sent to the bacteriology laboratory for the isolation of Escherichia coli and multidrug resistant isolates were characterized phenotypically and genotypically. Out of 106 fecal samples, E. coli was isolated from 101 samples. Although the majority of isolates belonged to phylogenetic groups A and B1, 14 out of 101 isolates were affiliated to group B2. A multidrug resistance phenotype was determined in 7 isolates, all of which had distinguishable genomic macrorestriction profiles. PCR analysis and sequencing revealed a variety of resistance genes, gene cassettes and cassette arrays in these multidrug resistant isolates. Resistance to fluoroquinolones was found in five E. coli isolates (two from a roe deer, one from a deer and two from a wild boar) and multiple mutations in the chromosomal topoisomerase genes were identified. In an E.coli isolate from a hare, the qnrB19 gene was detected. The same isolate carried an aadA23 gene cassette in class 1 integron. In addition, an extended- spectrum beta-lactamase blaCTX-M-1 gene was detected in an E. coli isolate from a roe deer. The gene was located on a conjugative multi resistance plasmid, which was transferable to a plasmid free E. coli recipient. In conclusion, a number of resistance genes and mobile genetic elements were detected in E. coli isolates from wildlife in Vojvodina, emphasizing the role of environmental pollution in spreading resistant bacteria.

OPTIMIZATION AND VALIDATION OF HPLC METHOD FOR TETRAMETHRIN DETERMINATION IN HUMAN SHAMPOO FORMULATION.

High-performance liquid chromatography (HPLC) method with diode array detection (DAD) were optimized and validated for separation and determination of tetramethrin in an antiparasitic human shampoo. In order to optimize separation conditions, two different columns, different column oven temperatures, as well as mobile phase composition and ratio, were tested. Best separation was achieved on the Supelcosil TM LC-18- DB column (4.6 x 250 mm), particle size 5 jim, with mobile phase methanol : water (78 : 22, v/v) at a flow rate of 0.8 mL/min and at temperature of 30°C. The detection wavelength of the detector was set at 220 nm. Under the optimum chromatographic conditions, standard calibration curve was measured with good linearity [r2 = 0.9997]. Accuracy of the method defined as a mean recovery of tetramethrin from shampoo matrix was 100.09%. The advantages of this method are that it can easily be used for the routine analysis of drug tetramethrin in pharmaceutical formulas and in all pharmaceutical researches involving tetramethrin.