Molecular characterization of extended-spectrum ß-lactamases-producing Enterobacteriaceae species in ground beef and chicken meat.

The objectives of this study were i) to characterize extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) using pheno- and genotyping methods, ii) to evaluate the antimicrobial resistance pattern against 10 antibiotics, and iii) to investigate class 1 integron (intI1) in 80 Enterobacteriaceae isolates obtained from chicken meat (n = 40; 47 isolates) and ground beef (n = 40; 33 isolates) samples. Through the study, we found that 55 (68.7 %) of 80 Enterobacteriaceae isolates were capable of ß-lactamase activity, and 38 (47.5 %) of them were multi-drug-resistant (MDR). The ground meat-origin isolates are 1.2 times more likely to produce imipenem resistance compared to chicken-meat-origin isolates (z = 2.1, p < 0.05, OR = 1.42). ESBL-E was found in 18 (22.5 %) of the isolates, 16.3 % of chicken meat and 6.3 % of ground beef origin. The bla genes were detected in 14 isolates [bla-TEM (n = 10; 12.5 %); bla-SHV (n = 4; 5.0 %); bla-CTX-M (n = 0)], where the predominant species were Escherichia (E.) coli and Citrobacter braakii. The nine ESBL-E isolates were MDR. Twenty-eight (35.0 %) of 80 isolates were found to be resistant to at least one third-generation cephalosporin, and eight (28.6 %) of them were also ESBL-E. Eleven of 16 (48.5 %) carbapenem-resistant isolates were ESBL-E. The intI1 gene was found in 13 (16.3 %) isolates, five of which were ESBL-E, and four of which were MDR. Co-existing with bla-TEM and the intI1 isolate was ESBL-E. coli, which was resistant to nine antibiotics. In conclusion, chicken meat and ground beef may pose a potential risk of containing ESBL-E, and bla genes which could be spread to the entire food chain.

Substituted naphthoxy-phthalonitrile derivatives: Synthesis, substituent effects, DFT, TD-DFT Calculations, antimicrobial properties and DNA interaction studies.

Herein, substituted-naphthol derivatives 4a-e were synthesized in two steps, namely the Diels Alder cycloaddition and Cu-catalyzed aromatization reactions, respectively. Then, pththalonitrile derivatives 7-12 have been prepared by a nucleophilic displacement reaction of 3-nitrophthalonitrile with the naphthol derivatives 4a-e, 5 and, obtained in excellent yields. Structural characterization of the compounds was identified by different spectroscopic techniques. Antimicrobial properties of the synthesized compounds were determined by the microdilution procedure against Gram-positive, Gram-negative bacteria, and yeast. Furthermore, the DNA interaction of the compounds were determined by gel electrophoresis. One of the most prominent findings is that compounds 9 and 10 have more inhibitory effects on Gram-positive bacteria than Gram-negative bacteria. These compounds especially exhibited the highest antibacterial potency against S. aureus (625 µg/mL) among Gram-positive bacteria. According to the plasmid DNA interaction results, the synthesized compounds caused changes in the structure and mobility of the plasmid DNA. Then, geometry optimizations and frequency calculations were conducted at B3LYP/6-311 G(d,p) level of DFT, and optimized structures were used for further analyses. The NBO results revealed that the π→π * and n→π * interactions were greatly contributed to lowering the stabilization energy of all compounds (7-12). FMO energy analyses showed that compound 9 has the biggest electrodonating power.

Presence of quorum sensing system, virulence genes, biofilm formation and relationship among them and class 1 integron in carbapenem-resistant clinical Pseudomonas aeruginosa isolates.

Carbapenems are the most effective agents for treating clinical P. aeruginosa (PsA) infections. During an infection, a quorum-sensing (QS) system and its regulating virulence genes have a great role. The aim of the study was to detect the presence of a las and rhl QS system and related virulence genes, biofilm formation and a class 1 (Cls1) integron. A total of 52 carbapenem-resistant PsA (CRPsA) isolates obtained from Kastamonu, Turkey was analyzed. For the isolation and identification of CRPsA isolates, a conventional culture method, an automated VITEK-2 compact system, and oprL gene-based molecular technique were applied. The two QS system genes were detected in 51 (98.1%), and co-existed of four two QS system genes (lasI/R and rhIl/R genes) were determined in 41 (78.8%) of the isolates. algD, lasB, toxA and aprA genes were detected in between 46.1 and 88.5%, and co-existence of four two QS system genes with four virulence genes were detected in 40.4% of the isolates. Biofilm formation using microtiter plate assay and slime production using Congo Red Agar and Cls1 integron were determined in 84.6%, 67.3% and 51.9% of the isolates, respectively. According to statistical analyses results, there was a significant positive correlation (p < .10) between the las and the rhl systems and a strongly and positive correlation (p < .01 or p < .05) between the rhl system-three virulence genes and slime production-and among some virulence genes. In conclusion, the CRPsA isolates tested in the study are highly virulent and QS systems have a significant role in pathogenesis.

3-Imino derivative-sulfahydantoins: Synthesis, in vitro antibacterial and cytotoxic activities and their DNA interactions.

Sulfahydantoins are five-membered rings found in the structure of chemicals that exhibit antibacterial, anti-inflammatory, and anticonvulsant properties. They also activate serine protease enzymes that catalyze the hydrolysis of peptide bonds. Five 3-imino sulfahydantoin compounds were synthesized by using Strecker synthesis reaction with minor modifications. We used reflux of various aldehydes with excess sulfamide in 85% methanol in the presence of sodium cyanide. The spectroscopic properties of these compounds were studied in detail. Antibacterial activities of all synthesized new compounds against four Gram-positive (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Streptococcus mutans) and four Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella Enteritidis) bacteria were investigated by disc diffusion and microdilution method. pBR322 plasmid DNA binding abilities of compounds were investigated in vitro by agarose gel electrophoresis. In addition, the cytotoxic activities of the compounds against the human malignant pleural mesothelioma (SPC212) cell line were determined by the MTT method. The remarkable result in this study is that the synthesized compounds, especially 4b, 4d, and 4e, have significant biological activities. It has been demonstrated that these compounds, which cause DNA damage, also have an important antibacterial effect on both Gram-negative and Gram-positive bacteria when results compared with the control group antibiotics. Compound 4e exhibited the highest antibacterial potency against Streptococcus mutans (24.33 ± 0.57) from Gram-positive bacteria and Pseudomonas aeruginosa (24.66 ± 1.15) from Gram-negative bacteria. At the same time, MTT results determined that compounds 4b, 4d, and 4e showed cytotoxic activity against the SPC212 cells. In particular, compound 4b had a high cytotoxic effect, and the IC50 value was determined as 6.25 µM.

Quorum sensing systems and related virulence factors in Pseudomonas aeruginosa isolated from chicken meat and ground beef.

The objective of this study was to evaluate 50 [chicken meat (n = 45) and ground beef (n = 5)] Pseudomonas aeruginosa isolates to determine the expression of the lasI and rhl QS systems, related virulence factors, and the presence of N-3-oxo-dodecanoyl homoserine lactone (AHL: 3-O-C12-HSL). For the isolation and identification of P. aeruginosa, conventional culture and oprL gene-based molecular techniques were used. In relation to QS systems, eight genes consisting of four intact and four internal (lasI/R, rhlI/R) genes were analyzed with PCR assay. The two QS systems genes in P. aeruginosa isolates from ground beef (80.00%) and chicken meat (76.00%) were present at quite high levels. The 3-O-C12-HSL was detected in 14.00% of the isolates. Both biofilm formation and motility were detected in 98.00% of the isolates. Protease activity was determined in 54.00% of the isolates. Pyocyanin production was detected in 48.00% of the isolates. The las system scores strongly and positively correlated with the rhl system (p ˂ .01). PYA moderately and positively correlated with protease (p ˂ .05). In addition, there was statistically significance between lasI and protease activity (p < .10), and rhlI and twitching motility (p < .10). In conclusion, the high number of isolates having QS systems and related virulence factors are critical for public health. Pyocyanin, protease, and biofilm formation can cause spoilage and play essential role in food spoilage and food safety.