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Antimicrobial activity of essential oils and five terpenoid compounds against Campylobacter jejuni in pure and mixed culture experiments
(Elsevier B.V., 2013) Kurekci, Cemil; Padmanabha, Jagadish; Bishop-Hurley, Sharon L.; Hassan, Errol; Al Jassim, Rafat A.M.; McSweeney, Christopher S.
The aim of this study was to examine the antimicrobial potential of three essential oils (EOs: tea tree oil, lemon myrtle oil and Leptospermum oil), five terpenoid compounds (?-bisabolol, ?-terpinene, cineole, nerolidol and terpinen-4-ol) and polyphenol against two strains of Campylobacter jejuni (ACM 3393 and the poultry isolate C338), Campylobacter coli and other Gram negative and Gram positive bacteria. Different formulations of neem oil (Azadirachta indica) with these compounds were also tested for synergistic interaction against all organisms. Antimicrobial activity was determined by the use of disc diffusion and broth dilution assays. All EOs tested were found to have strong antimicrobial activity against Campylobacter spp. with inhibitory concentrations in the range 0.001-1% (v/v). Among the single compounds, terpinen-4-ol showed the highest activity against Campylobacter spp. and other reference strains. Based on the antimicrobial activity and potential commerciality of these agents, lemon myrtle oil, ?-tops (?-terpineol. +. cineole. +. terpinen-4-ol) and terpinen-4-ol were also evaluated using an in vitro fermentation technique to test antimicrobial activity towards C. jejuni in the microbiota from the chicken-caecum. EO compounds (terpinen-4-ol and ?-tops) were antimicrobial towards C. jejuni at high doses (0.05%) without altering the fermentation profile. EOs and terpenoid compounds can have strong anti. Campylobacter activity without adversely affecting the fermentation potential of the chicken-caeca microbiota. EOs and their active compounds may have the potential to control C. jejuni colonisation and abundance in poultry. © 2013 Elsevier B.V.
Antimicrobial susceptibility pattern and SCCmec types of methicillin-resistant coagulase-negative staphylococci from subclinical bovine mastitis in Hatay, Turkey
(Natl Veterinary Research Inst, 2014) Aslantas, Ozkan; Yilmaz, Mehmet Ali; Yilmaz, Ebru Sebnem; Kurekci, Cemil
Eighty-nine isolates of coagulase-negative staphylococci (CoNS) of eight species from subclinical bovine mastitis were screened for the phenotypic and genotypic methicilline-resistance. In addition, all methicillin-resistant (MR) isolates indicating the mecA gene were examined by PCR for the antimicrobial susceptibility patterns, and staphylococcal cassette chromosome mec (SCCmec) types were also determined by multiplex PCR. A total of 21 (23.6%) CoNS isolates were found to be resistant to oxacillin in broth microdilution assay. All isolates phenotypically resistant to oxacillin did not have the mecA gene, which was only found in 14.6% (13) of the isolates. Most MR-CoNS isolates were highly resistant to erythromycin (92.3%), fusidic acid (84.6%), penicillin (76.9%), and rifampycin (61.5%), and susceptible to mupirocin (100%), tetracycline (100%), vancomycin (100%), clindamycin (92.3%), and sulfamethoxazole-trimethoprim (69.2%). In conclusion, a high rate of antimicrobial resistance among MR-CoNS isolated from food producing animals emphasises the need for periodic surveillance of their resistance.
Carrying system formula for eugenol encapsulation: glycodendritic polyamine dextran-G2.5, synthesis and in vitro antibacterial activity
(Springer, 2021) Bucak, Celile Demirbilek; Kurekci, Cemil; Dinc, Cemile Ozdemir
A novel 2.5th-generation glycodendritic polyamine dextran with 96 arms (DPADx) was synthesized by the divergent method. 2.5th-generation dendrimer was obtained from the successive triplicate Michael addition with two amidation reactions using 0.5th-generation tris(2-aminoethyl)amine (TAEA-G0.5) as the initiator core. 2.5th-generation polyamine hydrazide (PAH) was obtained from hydrazine monohydrate. Finally, dextran was conjugated with PAH and so DPADx was obtained. FTIR, H-1- and C-13-NMR, elemental analysis, GPC, XRD, SEM, TGA, DSC and dynamic viscosity were used for structural analysis of products. Loading efficiency, capacity and yield (%) of eugenol-encapsulated glycodendrimer were calculated as 70%, 84% and 35%, respectively; by using UV-Vis analysis results, antimicrobial activity against Gram-positive (Staphylococcus aureus, Listeria monocytogenes and Enterococcus cesseliflour) and Gram-negative (Escherichia coli and Salmonella Typhimurium) bacteria was proven. The current study demonstrated the usability of the novel dendritic glycopolymer as an innovative and environmentally friendly way to encapsulate and shuttle of EOs without altering sensory characteristics and the functionality of these molecules. Therefore, its commercial application is possible in a variety of fields, such as pharmaceutic and cosmetic industries.
Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey
(Korean Soc Food Science Animal Resources, 2016) Kurekci, Cemil; Onen, Sevda Pehlivanlar; Yipel, Mustafa; Aslantas, Ozkan; Gundogdu, Aycan
The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3')-Illa, ant(6)-Ia and aac(6')-leaph(2 '')-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey.
Characteristics of ciprofloxacin resistant Campylobacter spp. isolated from chicken meat in Turkey
(Springer, 2017) Kurekci, Cemil; Onen, Sevda Pehlivanlar
The objective of the current study was to investigate mutations in the gyrA and 23S rRNA gene fragments the high level ciprofloxacin resistant (HL-Cip(R)) Campylobacter isolates (C. jejuni n = 6 and and C. coli n = 9) obtained from chicken meat samples, in Turkey. PCR-based restriction fragment length polymorphism (RFLP) was used to characterize these isolates. In addition, the presence of several virulence traits among these isolates was also examined. Of the 15 HL-Cip(R) Campylobacter strains, there were eight unique RFLP banding patterns. All HL-Cip(R) Campylobacter strains had mutations in codon 86 (Thr-86 to Ile) in the gyrA gene. Four C. jejuni isolates had missense mutation of Asp-203 to Ser, whereas one C. jejuni strain also presented a change at Ala-40 to Ser. A2075G substitution in the 23S rRNA gene was identified in five isolates (C. coli n = 3 and C. jejuni n = 2), whereas none of the isolates had A2074G substitution. The tetO gene conferring resistance to tetracycline were observed among five Campylobacter isolates. Of Campylobacter strains, 13 (86.6 %) were found to be positive for one or more virulence factors, the cdt genes being the most detected. The results of the current study extends the current knowledge about molecular mechanisms for erythromycin and ciprofloxacin resistance as well as virulence traits by investigation of HL-Cip(R) Campylobacter isolates from chicken meat sold in Turkey.
Characterization of extended spectrum ?-lactamase ( ESBL)-producing Escherichia coli in Asi (Orontes) River in Turkey
(Iwa Publishing, 2017) Kurekci, Cemil; Aydin, Muhsin; Yipel, Mustafa; Katouli, Mohammad; Gundogdu, Aycan
In this study, the presence of extended spectrum beta-lactamase (ESBL)-producing Escherichia coli in aquatic environments (the Orontes River and an urban wastewater) was investigated. Fifty-four E. coli strains resistant to cefotaxime were isolated from the river waters and nearby waste water treatment plant and screened for ESBL gene variants, different classes of integrons and sulfonamide resistance genes. The ESBL-producing E. coli strains were further characterized by PhP-typing system, phylogenetic grouping and antimicrobial susceptibility testing. Of the 54 ESBL-producing strains, 14 (25.9%) belonged to four common PhP types and the remaining were of single types. CTX-M type ESBL genes were identified in 68% of the isolates. The most predominant specific CTX-M subtype identified was bla(CTX-M-15) (n=36), followed by bla(CTX-M-1) (n = 1). None of the isolates were SHV and OXA positive. Most of the ESBL positive isolates (n = 37; 68.5%) were harboring sul gene. This study indicates a widespread distribution of CTX-M-15 producing E. coli strains in the surface waters in part of Turkey, suggesting an aquatic reservoir for ESBL genes.
Design and modification of frog skin peptide brevinin-1GHa with enhanced antimicrobial activity on Gram-positive bacterial strains
(Springer Wien, 2022) Kara, Seyda; Kurekci, Cemil; Akcan, Muharrem
Naturally occurring frog skin peptides are one of largest sources of antimicrobial peptides that have many advantages including high potency, broad spectrum of targets and low susceptibility to multiple drug-resistance bacteria. However, they also have disadvantages such as hemolytic activity, low stability and high production costs. For these reasons, various strategies have been applied to overcome these drawbacks restricting their use in clinical trials. Previously reported brevinin-1GHa (BR-1GHa) is a 24 amino acid long antimicrobial peptide isolated from Hylarana guentheri with hemolytic activity. To enhance the antimicrobial activity of this peptide and to reduce its hemolytic activity, we designed five new temporin like analogues and examined their bioactivities. Temporins are another class of frog skin peptides without hemolytic activity and shorter than brevinins. When the antimicrobial activities of new analogues were examined against a panel of microorganisms, BR-1GHa-3, in which two alanine residues in the truncated version of BR-1GHa were replaced with leucine, exhibited significantly improved antimicrobial activity against Gram-positive bacterial strains (e.g., S. aureus ATCC 29213 and E. casseliflavus ATCC 700327) with lower hemolytic activity compared to the BR-1GHa peptide. Furthermore, BR-1GHa-4 analogue, in which Gly3 was replaced with Pro, did not show any hemolytic activity except for highest (128 mu M) concentration tested and have a strong antimicrobial effect on Gram-positive bacteria (e.g., E. faecalis ATCC 51299 and B. cereus ATCC 13061).
Determination of selected antibiotics in farmed fish species using LC-MS/MS
(Wiley, 2017) Yipel, Mustafa; Kurekci, Cemil; Tekeli, Ibrahim O.; Metli, Murat; Sakin, Fatih
The aim of the study was to monitor the occurrence of 37 antibiotics from different classes including fluoroquinolone, tetracycline, macrolide, sulphonamide, penicillin, amphenicol and cephalosporin in three different farmed fish species (n=75; rainbow trout, see bass, gilthead see bream) from five cities in Turkey. A method for LC-MS/MS was optimized and validated to assess these antibiotics. As a result, 25 samples showed contamination with at least one antibiotic residue. The most detected antibiotics were norfloxacin (NOR) (18.7%), marbofloxacin (MAR) (12%), tetracycline (TC) (10.7), danofloxacin (DAN) (9.3%), oxytetracycline (OTC) (9.3%), tilmicosin (TLM) (8%) and enrofloxacin (ENR) (6.7%). A total of 17.3% of samples examined were found to be contaminated with residues exceeding the maximum residue limits (MRLs). The results indicate that antibiotics are frequently used in aquaculture production without the lack of knowledge. This study also revealed that the consumption of farmed fish could produce a public health concern as the level of residues for some antibiotics was much higher than MRLs.
Different fosA genes were found on mobile genetic elements in Escherichia coli from wastewaters of hospitals and municipals in Turkey
(Elsevier, 2022) Guneri, Cansu Onlen; Stingl, Kerstin; Grobbel, Mirjam; Hammerl, Jens Andre; Kurekci, Cemil
Aims: The increasing number of globally established fosfomycin-resistant (FosR) Gram-negative bacteria inspired us to investigate the occurrence of FosR Enterobacterales populations (esp. E. coli) in samples of city wastewater treatment plants (WWTPs) and hospital sewage in Hatay, Turkey. FosR target bacteria were further characterized for their clonal relatedness, resistomes and mobile genetic elements (MGEs) to evaluate their impact on fosfomycin resistance dissemination. Methods: A total of 44 samples from raw and treated waters of WWTPs as well as of two hospitals in the Hatay province were subjected to selective cultivation for recovering FosR Enterobacterales. The presence of fosA was verified by PCR and Sanger amplicon sequencing. Detected E. coli were further evaluated against antimicrobial susceptibility-testing, macrorestriction profiling (PFGE) and whole-genome sequencing (WGS). Bioinformatics analysis was performed for genome subtyping (i.e., MLST, serotype), resistome/virulome determination and dissection of the genetic determinants of plasmidic fosA3/4 resistances. Results: Besides ten non-E. coli Enterobacterales, 29 E. coli were collected within this study. In silico-based subtyping revealed that E. coli isolates were assigned to six different serovars and 14 sequence types (ST), while O8:H21 and ST410 represented the major prevalent types, respectively. Fosfomycin resistance in the isolates was found to be mediated by the fosA4 (n = 18), fosA3 (n = 10) and fosA (n = 1), which are frequently associated with transmissible MGEs. Reconstruction of plasmid-associated fosA gene context revealed a linkage between the resistance cassette and IS6 (IS26 family) transposases, which might represent a major driver for the distribution of the genes and the generation of novel fosA-carrying plasmids. Conclusions: The occurrence of plasmid-mediated, transmissible FosR in E. coli from wastewater pose a foreseeable threat to One-Health. To minimize further spread of the resistances in bacterial populations associated with environmental, animal and human health further resistance monitoring and management strategies must be developed.
Disinfectant and heavy metal resistance profiles in extended spectrum ?-lactamase (ESBL) producing Escherichia coli isolates from chicken meat samples
(Elsevier, 2022) Sahin, Seyda; Mogulkoc, Mahmut Niyazi; Kurekci, Cemil
Biocidal compounds are frequently used as disinfectants in poultry industry and their widespread usage has risen concern due to the co-selection and persistence of antimicrobial resistance among bacteria. In this study, extended spectrum beta-lactamase producing (ESBL) Escherichia coli isolates (n = 60) obtained from chicken meat were characterized by Pulsed Field Gel Electrophoresis (PFGE) and further tested for disinfectant and heavy metal resistance phenotypically and genotypically. Plasmid replicon types of these isolates were also determined. ESBL producing E. coli isolates were found to be resistant to ciprofloxacin (48.3 %) and gentamicin (15 %). The majority of these isolates (46.5 %) carried blaCTX-M-55 gene. The isolates showed higher minimal inhibitory concentrations to cetylpyridinium chloride (90 %), cetyltrimethylammonium bromide (50 %), hexadecyl-trimethylammonium bromide (46.7 %), triclosan (38.3 %), benzalkonium chloride (28.3 %), chlorhexidine (21.7 %), acriflavine (3.3 %), benzethonium chloride (1.7 %) and N-alkyl dimethyl benzyl ammonium chloride (1.7 %), but 18.3 % of the isolates were resistant to triclosan. Of the quaternary ammonium compounds (QACs) tolerance genes, mdfA, sugE(c), ydgE and ydgF were most present in all isolates, but the qacE, qacG, oqxA and oqxB genes were not detected. Of genes mediating the heavy metal resistance, the zitB gene was detected in all isolates, whereas the copA and cueO genes were detected in 96.67 % and 95 % of isolates, respectively. The IncFIB plasmid was commonly present (93.3 %) in ESBL producing E. coli isolates. Consequently, given the detection of genes mediating disinfectant and heavy metal resistance commonly in ESBL producing E. coli isolates as well as high rate of MICs against disinfectant compounds, the use of QACs for decontamination of the facilities may not be as effective as expected in poultry sector in Turkey.
Effect of essential oil supplementation to diet on meat quality, fatty acid composition, performance parameters and intestinal microbiota of Japanese quails
(Wiley, 2021) Kurekci, Cemil; Ozsoy, Bulent; Hassan, Errol; Ozkan, Huseyin; Gundogdu, Aycan; Ozsoy, Sule Yurdagul; Yakan, Akin
The effect of essential oil (EO) supplementation on carcass characteristics of Japanese quails and interactions between ingredients and intestinal morphology were investigated in this study. A total of 250 quails were fed different diet: D1, basal diet (BD); D2, BD plus palmarosa oil (PO; 100 mu g/kg diet); D3, BD plus lemon myrtle oil (LMO; 100 mu g/kg diet); D4, BD plus alpha-Tops (mixture of alpha-terpineol, cineole and terpinene-4-ol; 100 mu g/kg diet); and D5, BD plus cyclodextrin. Overall growth performance was determined at multiple time points during 35 days of experiment. Carcass characteristics (fatty acid, pH and colour), intestinal morphology and the expression levels of meat quality-related genes including the insulin-like growth factor (IGF-1), myogenin and avian uncoupling protein (avUCP) were examined at the end of the trial. Additionally, intestinal microbiome of quails was studied by next-generation sequencing-based culture-independent analysis. Although the inclusion of EOs into the diet had no effect on the growth performance of quails and the microbial profile, the significant changes in pH(24)and colour (a*) of the quail's breast muscle (p < .05) in the group receiving PO were observed. Additionally, oleic acid content in the breast muscle was significantly higher in the EOs supplemented groups (p < .01). Quails fed the PO supplemented diet had higher villus and relatively rich in oleic acid. The expression levels of IGF-1 and myogenin genes in quail's muscle were not affected, but the expression of avUCP gene was significantly lower in quails fed with LMO and alpha-Tops (p < .05). The results demonstrated variable effects of these treatments on intestinal morphology. Taken together, dietary inclusion of EOs is found to be beneficial and hence can be recommended for improving the quality of poultry meat.
Effects of feeding plant-derived agents on the colonization of Campylobacter jejuni in broiler chickens
(Elsevier, 2014) Kurekci, Cemil; Al Jassim, Rafat; Hassan, Errol; Bishop-Hurley, Sharon L.; Padmanabha, Jagadish; McSweeney, Christopher S.
The aim of this work was to test the potential use of plant-derived extracts and compounds to control Campylobacter jejuni in broiler chickens. Over a 7-wk feeding period, birds were fed a commercial diet with or without plant extracts (Acacia decurrens, Eremophila glabra), essential oil [lemon myrtle oil (LMO)], plant secondary compounds [terpinene-4-ol and a-tops (including a-terpineol, cineole, and terpinene-4-ol)], and the antibiotic virginiamycin. Traditional culture and real-time quantitative PCR techniques were used to enumerate the numbers of C. jejuni in chicken fecal and cecal samples. In addition, BW and feed intake were recorded weekly for the calculation of BW gain and feed conversion ratio. The mean log(10) counts of C. jejuni were similar (P > 0.05) across treatments. However, significantly lower levels of fecal Campylobacter counts (P < 0.05) were recorded at d 41 for the a-tops treatment by culture methods. No differences (P > 0.05) in BW gain were obtained for dietary supplementation, except for the E. glabra extract, which had a negative impact (P < 0.001) on BW, resulting in sporadic death. Results from this study suggest that supplemental natural compounds used in the current study did not reduce the shedding of C. jejuni to desired levels.
First report of Escherichia coli carrying the mobile colistin resistance gene mcr-1 in Turkey
(Elsevier Sci Ltd, 2018) Kurekci, Cemil; Aydin, Muhsin; Nalbantoglu, Ozkan Ufuk; Gundogdu, Aycan
[Abstract Not Available]
Isolation, molecular characterization and antimicrobial resistance of enterobacteriaceae isolated from fish and seafood
(Elsevier Sci Ltd, 2018) Leila Dib, Amira; Agabou, Amir; Chahed, Amina; Kurekci, Cemil; Moreno, Elena; Espigares, Miguel; Espigares, Elena
This current study attempted to examine the occurrence rates of Enterobacteriaceae in seafood samples collected from different fishmongers in the province of Constantine (Northeast Algeria) over a one-year period. Total and fecal coliforms were enumerated and selected Enterobacteriaceae colonies were identified. Escherichia coil (E. coli) and Salmonella isolates were serotyped, after which their antimicrobial susceptibility patterns were determined. Extended-spectrum beta-lactamases (ESBL) encoding genes, virulence genes (stx1, stx2 and eae) and plasmid-harboring were searched among E. coli isolates and their clonality was also assessed by pulsed-field gel electrophoresis (PFGE). Results showed that fecal coliform contamination levels are beyond the recommended limits. All strains of Salmonella (n = 2) isolated were of serovar infantis. One E. coli isolate from sardines belonged to serotype O127 and two others (one from sardines and one from shrimps) were identified as serotype O125. One E. coli isolate from sardines was characterized as enterohemorrhagic (EHEC) and six others as shiga toxin-producing (STEC) (three from sardines and three from shrimps). All tested strains were multidrug resistant, with five E. coil strains showing an ESBL phenotype and harboring the bla(CTX-M-15) gene (four from sardines and one from shrimps). Plasmids of differents sizes were extracted from seven E. coli isolates (five from sardines and two from shrimps) with many strains carrying more than one plasmid. E. coli isolates belonged to two phylogenetic groups (B1 and, mainly, E) and scattered on eight distinct clones as defined by PFGE. Some strains are grouped within the same cluster regardless of their origin and characteristics, indicating a common source of contamination. These findings demonstrate that, in the study region, sardines and shrimp may play an important role in the dissemination of virulent and multi-drug resistant enterobacteria strains. (C) 2018 Elsevier Ltd. All rights reserved.
Linalool and eugenol exhibit apoptotic potential on hela and caco-2 cells through the modulation of src kinases and ADAMTS proteases while only eugenol displays anti-angiogenic features on HeLa cells
(Springer, 2022) Kisacam, Mehmet Ali; Sakin, Fatih; Irtegun-Kandemir, Sevgi; Pektanc-Sengul, Gulsum; Kurekci, Cemil
The cytotoxic effects of linalool and eugenol on HeLa and Caco-2 cancer cells were investigated. The expression of the Fyn, Hck, and ADAMTS genes and Bcl-2, Bax, VEGF proteins were determined through the real-time-qPCR and Western blot analysis, respectively. IC50 values of linalool on HeLa cell were 799.6, 1228, and 1239 mu g/mL after 24, 48, and 72 h, respectively, whereas those of eugenol were 388, 94.35, and 73.78 mu g/mL. IC50 values in Caco-2 cells were 887.7, 1259, and 1356 mu g/mL for linalool whereas those of eugenol were 452.7, 578.3, and 433.3 mu g/mL after 24, 48, and 72 h, respectively. As a control, Hek-293 IC50 values were 1047 and 556.7 mu g/mL for linalool and eugenol, respectively. Linalool at 1024 mu g/mL concentration increased Bax and Bcl-2 levels significantly in both cell lines (p < 0.001). However, eugenol treatment did not alter Bax levels (p > 0.05), but it decreased Bcl-2 levels significantly (p < 0.001). Additionally, 1024 mu g/mL linalool exposure increased Fyn gene expression in Caco-2 cells, which was not observed for HeLa cells. Unlike linalool, eugenol upregulated ADAMTS1 gene expression and decreased VEGF levels in HeLa cells. On the contrary, in Caco-2 cells, eugenol treatment did not affect ADAMTS1 levels, whilst linalool upregulated ADAMTS1 levels, especially at 1024 mu g/mL concentration. VEGF levels increased in Caco-2 cells following eugenol treatment. ADAMTS3 levels decreased in Caco-2 cells with exception of 1024 mu g/mL linalool treatment. These results indicated the anti-proliferative, apoptotic effects of plant-derived natural compounds. It is also revealed that eugenol might also display antiangiogenic properties on HeLa cells in addition to its apoptotic effects.
Molecular mechanisms and genomic basis of tigecycline-resistant Enterobacterales from swine slaughterhouses
(Elsevier Gmbh, 2022) Peng, Kai; Wang, Qian; Li, Yan; Wang, Mianzhi; Kurekci, Cemil; Li, Ruichao; Wang, Zhiqiang
The continuous emergence of tigecycline-resistant bacteria is undermining the effectiveness of clinical tigecy-cline. Environmental tigecycline-resistant bacteria have the potential to infect humans through human -environment interactions. Furthermore, the mechanisms of tigecycline resistance in Enterobacterales are complicated. In this study, we aimed to investigate the additional pathways of tigecycline resistance in envi-ronmental Enterobacterales besides tet(X) and tmexCD-toprJ. During the years 2019-2020, tigecycline-resistant Enterobacterales (n = 45) negative for tet(X) and tmexCD-toprJ were recovered from 328 different samples from two slaughterhouses. Five distinct bacteria species were identified, of which Klebsiella pneumoniae (n = 37) was the most common, with K. pneumoniae ST45 and ST35 being the predominant clones. Tigecycline resistance determinants analysis showed that tet(A) mutations and ramR inactivation were the most prevalent mechanisms for tigecycline resistance in the 45 strains. Two known tet(A) variants (type 1 and tet(A)-v) and one novel tet(A) variant (type 3) were identified. Cloning experiments confirmed that the novel type 3 tet(A) could enhance the 4 -fold MIC for tigecycline. Inactivation of ramR was induced by either point mutations or indels of sequences, which could result in the overexpression of AcrAB pump genes leading to tigecycline resistance. In addition, all isolates were resistant to a wide range of antimicrobials and carried various resistance genes. These findings enriched the epidemiological and genomic characterizations of tigecycline-resistant Enterobacterales from slaughterhouses and contributed to a better understanding of the complex mechanisms of tigecycline resistance in environmental bacteria.
Occurrence and characterization of ciprofloxacin-resistant Escherichia coli from bovine and ovine bulk tank milk samples in Turkey
(Wiley, 2021) Kurekci, Cemil; Aydin, Muhsin; Tekeli, Ibrahim Ozan; Ambarcioglu, Pinar; Sengul, Seydi Ahmet; Sakin, Fatih
The objective of this study was to examine the occurrence and characteristics of ciprofloxacin-resistant (Cip(R)) Escherichia coli isolates on bulk tank milk (BTM) samples (bovine and ovine origins) in Turkey. A total of 91 BTM samples (41.7%, 95% confidence intervals 35.2-48.6%) out of 218 were found to be positive for Cip(R) E. coli isolates (MIC values of >= 4 mu g/ml). Analysis of PFGE fingerprint profile for E. coli isolates resulted in the 55 different pulsotypes based on >85% homology. All isolates were resistant to enrofloxacin and nalidixic acid and the resistance rates in bovine and ovine origin isolates were 94.9 and 78.1% for norfloxacin (p < .05) and 27.1 and 34.4% for levofloxacin, respectively. Additionally, resistance to non-quinolone antibiotics was commonly observed against tetracycline (resistance rates in bovine and ovine = 91.5 and 87.5%, respectively), trimethoprim-sulfamethoxazole (83.1 and 93.8%, respectively), gentamycin (15.3 and 40.6%, respectively, p < .05) and chloramphenicol (23.7 and 65.6%, respectively, p < .05). The qnrS1 gene (3.1 and 6.8%, respectively) was the most prevalent PMQR genes in isolates from ovine and bovine origins, followed by aac (6 ')-Ib-cr (0 and 5.1%, respectively) and qnrB19 (0 and 1.7%, respectively). The other resistance genes including tetA, tetB, strA/B, aPozhA1, aadA, aadB, bla(CTX-M), and bla(TEM) were also identified in various frequencies. The most frequently observed virulence trait was fimH. The low-level presence of PMQR genes and as well as some virulence traits is an important finding, yet the results of this study are worrisome because quinolone antibiotics are still the drugs of choice for severe infections in humans.
Occurrence and health risk assessment of aflatoxins and ochratoxin a in Surk, a Turkish dairy food, as studied by HPLC
(Elsevier Sci Ltd, 2018) Sakin, Fatih; Tekeli, Ibrahim Ozan; Yipel, Mustafa; Kurekci, Cemil
The concentration of aflatoxins (AFs) and ochratoxin A (OTA) in Surk cheese samples was determined by high-performance liquid chromatography with fluorescence detection (HPLC-FD) system, for which the analytical method was validated according to the guidelines issued by European Commission (EC). Additionally, cancer related health risk via dietary intake of Surk was assessed by calculating estimated daily intake (EDI) and hazard index (HI) for aflatoxin M-1 (AFM(1)), and Margin of Exposure (MoE) for aflatoxin B-1 (AFB(1)) and Provisional tolerable weekly intake (PTWI) for OTA. OTA was the most frequently detected toxin that was presented in 28 samples with concentration ranging from 0.058 to 5.04 mu g kg(-1)53.3% of samples contained AFM(1) at levels > LOQ of 0.07 mu g kg(-1), of which none exceeded the permissible maximum limits (0.5 mu g kg(-1)) established by Turkish legislation. Surk samples were found to contain AFB(1) at mean concentration of 0.610 mu g kg(-1). The range of concentrations of AFs and OTA in Surk observed in the current study was found to be below the official Turkish standard determined for various foodstuffs. However, HI from consuming Surk was found to be 1.02 mu g kg(-1) bw for AFM(1), and MoE value for AFB(1) was found to be 2982 which clearly indicates health risk AFM(1) and AFB(1) to Surk consumers. However. OTA contamination level was found to be low to produce health hazards according to PTWI value. According to health risk assessment of this study presents the first data about occurrence of AFs and OTA in Surk, yet data should be updated based on seasonal monitoring and consumption habits of both adults and infants. (C) 2018 Published by Elsevier Ltd.
Occurrence, genetic characterization and antimicrobial resistance of extended spectrum ?-lactamase producing Escherichia coli isolated from Surk samples, a traditional turkish cheese
(Springer, 2016) Kurekci, Cemil; Arkadas, Muge; Avsar, Yahya Kemal
This study was carried out to provide information regarding the presence of extended spectrum beta-lactamase (ESBL) producing Escherichia coli isolated from Surk cheese samples. For this purpose, ESBL-producing E. coli strains were isolated from 87 Surk samples and isolates were screened for the common ESBL-types, presence of integrons and sul genes via PCR. All ESBL-producing E. coli strains were also allotted to phylogenetic groups and typed by PFGE. Twelve ESBL-producing E. coli (13.8 %) displayed eight distinct PFGE profiles and were exhibited resistance to tetracycline (41.7 %), trimethoprim-sulfamethoxazole (25 %), doxycycline (25 %) and chloramphenicol (16.7 %). Eleven isolates carried the bla (CTX-M-15) gene (n = 7) and bla (CTX-M-15) + bla (TEM-1) genes (n = 4). Eleven isolates carried class1 and 2 integrons (intl1, 9 isolates and intl1 + intl2, two isolates) whereas four isolates carried sul1 (n = 2) and both sul1 + sul2 (n = 2) genes. The current study revealed a high rate of E. coli producing CTX-M-15 enzymes indicating a significant source for this organism in humans.
Prevalence of ?-Lactamase Producing Escherichia coli from Retail Meat in Turkey
(Wiley, 2015) Onen, Sevda Pehlivanlar; Aslantas, Ozkan; Yilmaz, Ebru Sebnem; Kurekci, Cemil
Extended spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC beta-lactamase (pAmpC) producing Escherichia coli have been shown to be present in humans and animals representing a significant problem worldwide. This study aimed to search the presence of ESBL and/or AmpC-producing E. coli in retail meats (chicken and beef) in Turkey. A total of 88 beta-lactamase-producing E. coli were isolated from chicken (n = 81/100) and beef meat (n = 7/100) samples and their susceptibility to several antimicrobials were tested using disc diffusion method. E. coli isolates were further characterized for their phylogenetic groups. beta-Lactamase encoding (bla(TEM), bla(SHV), bla(OXA), bla(CTX-M), and bla(AmpC)) and quinolone resistance genes (qnrA, qnrB, qnrS, qepA, and acc(6')-Ib-cr) were also secreened by polymerase chain reaction (PCR). However, in regard to beta-lactamase genes, 84 of 88 isolates were positive for bla(CTX-M-1) (n = 39), bla(CTX-M-3) (n = 5), bla(CTX-M-15) (n = 4), bla(TEM-1b) (n = 2), bla(SHV-12) (n = 1), bla(CTX-M-1/blaTEM-1b) (n = 10), bla(CTX-M-1)/bla(TEM-1b)/bla(SHV-5) (n = 1), bla(CTX-M-1)/bla(CMY-2) (n = 1) and bla(TEM-1b)/bla(CMY-2) (n = 6), bla(CTX-M-15)/bla(SHV-12) (n = 1), bla(CTX-M-15)/bla(TEM-1b) (n = 1), bla(TEM-1b)/bla(SHV-12) (n = 1), and bla(CMY-2) (n = 12) genes. Resistance to cefuroxime (75.6% and 85.7%), nalidixic acid (89% and 85.7%), tetracycline (91.4% and 100%), streptomycin (40.2% and 100%), and trimethoprim-sulfamethoxazole (36.6% and 85.7%) was observed among strains isolated from chicken and beef, respectively. However, all isolates were found to be susceptible to amikacin, imipenem, and cefepime. Resistance to ampicillin and cefoxitin was significantly linked to bla(CMY-2) gene, while there was a significant correlation between CTX-M type ESBL and antimicrobial resistance to cefuroxime and streptomycin (P < 0.05). The results of this study suggest that raw chicken retail meats are highly contaminated with ESBL-producing E. coli implementing a great risk to human health in Turkey.

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