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524500.9624Antimicrobial Resistance in U.S. Retail Ground Beef with and without Label Claims Regarding Antibiotic Use. ABSTRACT: Antibiotics used during food animal production account for approximately 77% of U.S. antimicrobial consumption by mass. Ground beef products labeled as raised without antibiotics (RWA) are perceived to harbor lower levels of antimicrobial-resistant bacteria than conventional (CONV) products with no label claims regarding antimicrobial use. Retail ground beef samples were obtained from six U.S. cities. Samples with an RWA or U.S. Department of Agriculture Organic claim (n = 299) were assigned to the RWA production system. Samples lacking these claims (n = 300) were assigned to the CONV production system. Each sample was cultured for the detection of five antimicrobial-resistant bacteria. Genomic DNA was isolated from each sample, and a quantitative PCR assay was used to determine the abundance of 10 antimicrobial resistance (AMR) genes. Prevalence of tetracycline-resistant Escherichia coli (CONV, 46.3%; RWA, 34.4%; P < 0.01) and erythromycin-resistant Enterococcus (CONV, 48.0%; RWA, 37.5%; P = 0.01) was higher in CONV ground beef. Salmonella was detected in 1.2% of samples. The AMR gene blaCTX-M (CONV, 4.1 log-normalized abundance; RWA, 3.8 log-normalized abundance; P < 0.01) was more abundant in CONV ground beef. The AMR genes mecA (CONV, 4.4 log-normalized abundance; RWA, 4.9 log-normalized abundance; P = 0.05), tet(A) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), tet(B) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), and tet(M) (CONV, 5.4 log-normalized abundance; RWA, 5.8 log-normalized abundance; P < 0.01) were more abundant in RWA ground beef. Although these results suggest that antimicrobial use during U.S. cattle production does not increase human exposure to antimicrobial-resistant bacteria via ground beef, quantitative microbiological risk assessments are required for authoritative determination of the human health impacts of the use of antimicrobial agents during beef production.202133302298
353910.9621Exposure Levels of Airborne Fungi, Bacteria, and Antibiotic Resistance Genes in Cotton Farms during Cotton Harvesting and Evaluations of N95 Respirators against These Bioaerosols. The USA is the third-leading cotton-producing country worldwide and cotton farming is common in the state of Georgia. Cotton harvest can be a significant contributor to airborne microbial exposures to farmers and nearby rural communities. The use of respirators or masks is one of the viable options for reducing organic dust and bioaerosol exposures among farmers. Unfortunately, the OSHA Respiratory Protection Standard (29 CFR Part 1910.134) does not apply to agricultural workplaces and the filtration efficiency of N95 respirators was never field-tested against airborne microorganisms and antibiotic resistance genes (ARGs) during cotton harvesting. This study addressed these two information gaps. Airborne culturable microorganisms were sampled using an SAS Super 100 Air Sampler in three cotton farms during cotton harvesting, and colonies were counted and converted to airborne concentrations. Genomic DNA was extracted from air samples using a PowerSoil(®) DNA Isolation Kit. A series of comparative critical threshold (2(-ΔΔCT)) real-time PCR was used to quantify targeted bacterial (16S rRNA) genes and major ARGs. Two N95 facepiece respirator models (cup-shaped and pleated) were evaluated for their protection against culturable bacteria and fungi, total microbial load in terms of surface ATP levels, and ARGs using a field experimental setup. Overall, culturable microbial exposure levels ranged between 10(3) and 10(4) CFU/m(3) during cotton harvesting, which was lower when compared with bioaerosol loads reported earlier during other types of grain harvesting. The findings suggested that cotton harvesting works can release antibiotic resistance genes in farm air and the highest abundance was observed for phenicol. Field experimental data suggested that tested N95 respirators did not provide desirable >95% protections against culturable microorganisms, the total microbial load, and ARGs during cotton harvesting.202337375063
135220.9619Bacterial Diversity and Antimicrobial Resistance of Microorganisms Isolated from Teat Cup Liners in Dairy Farms in Shandong Province, China. Global milk consumption exceeds 800 million tons a year and is still growing. Milk quality and its products are critical to human health. A teat cup makes direct contact with the cow's teats during milking and its cleanliness is very important for the quality of raw milk. In this study, the microorganism from post-milking teat cup liners were collected from six dairy farms in Shandong Province of China, the bacterial species were identified using microbial mass spectrometry, the minimum inhibitory concentrations of the isolated strains against ten antimicrobial agents were determined using the broth microdilution method, and the antimicrobial resistance genes were detected by PCR. The results indicated that the most frequently isolated bacteria in this study were Bacillus licheniformis (39/276, 14.13%), followed by Bacillus pumilus (20/276, 7.25%), Bacillus cereus (17/276, 6.16%), and Bacillus subtili (16/276, 5.80%). The isolates exhibited the highest average resistance to lincomycin (87.37%), followed by sulfadiazine (61.05%) and streptomycin (42.63%); the highest detection rate of resistance genes was Sul1 (55.43%), followed by ant(4') (51.09%), tet(M) (25.36%), bla(KPC) (3.62%) and qnrS (3.62%). These findings imply the necessity for enhanced measures in disinfecting cow udders and milking equipment, highlighting the persistently challenging issue of antimicrobial resistance in Shandong Province.202439123692
601230.9618Metal resistance-related genes are differently expressed in response to copper and zinc ion in six Acidithiobacillus ferrooxidans strains. Metal resistance of acidophilic bacteria is very significant during bioleaching of copper ores since high concentration of metal is harmful to the growth of microorganisms. The resistance levels of six Acidithiobacillus ferrooxidans strains to 0.15 M copper and 0.2 M zinc were investigated, and eight metal resistance-related genes (afe-0022, afe-0326, afe-0329, afe-1143, afe-0602, afe-0603, afe-0604, and afe-1788) were sequenced and analyzed. The transcriptional expression levels of eight possible metal tolerance genes in six A. ferrooxidans strains exposed to 0.15 M Cu(2+) and 0.2 M Zn(2+) were determined by real-time quantitative PCR (RT-qPCR), respectively. The copper resistance levels of six A. ferrooxidans strains declined followed by DY26, DX5, DY15, GD-B, GD-0, and YTW. The zinc tolerance levels of six A. ferrooxidans strains exposed to 0.2 M Zn(2+) from high to low were YTW > GD-B > DY26 > GD-0 > DX5 > DY15. Seven metal tolerance-related genes all presented in the genome of six strains, except afe-0604. The metal resistance-related genes showed different transcriptional expression patterns in six A. ferrooxidans strains. The expression of gene afe-0326 and afe-0022 in six A. ferrooxidans strains in response to 0.15 M Cu(2+) showed the same trend with the resistance levels. The expression levels of genes afe-0602, afe-0603, afe-0604, and afe-1788 in six strains response to 0.2 M Zn(2+) did not show a clear correlation between the zinc tolerance levels of six strains. According to the results of RT-qPCR and bioinformatics analysis, the proteins encoded by afe-0022, afe-0326, afe-0329, and afe-1143 were related to Cu(2+) transport of A. ferrooxidans strains.201425023638
82840.9616Screening for Resistant Bacteria, Antimicrobial Resistance Genes, Sexually Transmitted Infections and Schistosoma spp. in Tissue Samples from Predominantly Vaginally Delivered Placentae in Ivory Coast and Ghana. Medical complications during pregnancy have been frequently reported from Western Africa with a particular importance of infectious complications. Placental tissue can either become the target of infectious agents itself, such as, e.g., in the case of urogenital schistosomiasis, or be subjected to contamination with colonizing or infection-associated microorganisms of the cervix or the vagina during vaginal delivery. In the retrospective cross-sectional assessment presented here, the quantitative dimension of infection or colonization with selected resistant or pathogenic bacteria and parasites was regionally assessed. To do so, 274 collected placental tissues from Ivory Coastal and Ghanaian women were subjected to selective growth of resistant bacteria, as well as to molecular screening for beta-lactamase genes, Schistosoma spp. and selected bacterial causative agents of sexually transmitted infections (STI). Panton-Valentine-negative methicillin-resistant Staphylococcus aureus (MRSA) was grown from 1.8% of the tissue samples, comprising the spa types t008 and t688, as well as the newly detected ones, t12101 (n = 2) and t12102. While the culture-based recovery of resistant Enterobacterales and nonfermentative rod-shaped Gram-negative bacteria failed, molecular assessments confirmed beta-lactamase genes in 31.0% of the samples with multiple detections of up to four resistance genes per sample and bla(CTX-M), bla(IMP), bla(GES), bla(VIM), bla(OXA-58)-like, bla(NDM), bla(OXA-23)-like, bla(OXA-48)-like and bla(KPC) occurring in descending order of frequency. The beta-lactamase genes bla(OXA-40/24)-like, bla(NMC_A/IMI), bla(BIC), bla(SME), bla(GIM) and bla(DIM) were not detected. DNA of the urogenital schistosomiasis-associated Schistosoma haematobium complex was recorded in 18.6% of the samples, but only a single positive signal for S. mansoni with a high cycle-threshold value in real-time PCR was found. Of note, higher rates of schistosomiasis were observed in Ghana (54.9% vs. 10.3% in Ivory Coast) and Cesarean section was much more frequent in schistosomiasis patients (61.9% vs. 14.8% in women without Schistosoma spp. DNA in the placenta). Nucleic acid sequences of nonlymphogranuloma-venereum-associated Chlamydia trachomatis and of Neisseria gonorrhoeae were recorded in 1.1% and 1.9% of the samples, respectively, while molecular attempts to diagnose Treponema pallidum and Mycoplasma genitalium did not lead to positive results. Molecular detection of Schistosoma spp. or STI-associated pathogens was only exceptionally associated with multiple resistance gene detections in the same sample, suggesting epidemiological distinctness. In conclusion, the assessment confirmed considerable prevalence of urogenital schistosomiasis and resistant bacterial colonization, as well as a regionally expected abundance of STI-associated pathogens. Continuous screening offers seem advisable to minimize the risks for the pregnant women and their newborns.202337623959
125950.9610Tetracycline resistance potential of heterotrophic bacteria isolated from freshwater fin-fish aquaculture system. AIMS: This study investigated the tetracycline resistance potential of heterotrophic bacteria isolated from twenty-four freshwater fin-fish culture ponds in Andhra Pradesh, India. METHODS AND RESULTS: A total of 261 tetracycline resistant bacteria (tetR) were recovered from pond water, pond sediment, fish gills, fish intestine, and fish feed. Bacteria with high tetracycline resistance (tetHR) (n = 30) that were resistant to tetracycline concentrations above 128  μg mL-1 were predominantly Lactococcus garvieae followed by Enterobacter spp., Lactococcus lactis, Enterobacter hormaechei, Staphylococcus arlettae, Streptococcus lutetiensis, Staphylococcus spp., Brevundimonas faecalis, Exiguobacterium profundum, Lysinibacillus spp., Stutzerimonas stutzeri, Enterobacter cloacae, and Lactococcus taiwanensis. Resistance to 1024 μg mL-1 of tetracycline was observed in L. garvieae, S. arlettae, Enterobacter spp., B. faecalis. Tet(A) (67%) was the predominant resistance gene in tetHR followed by tet(L), tet(S), tet(K), and tet(M). At similar concentrations of exposure, tetracycline procured at the farm level (69.5% potency) exhibited lower inhibition against tetHR bacteria compared to pure tetracycline (99% potency). The tetHR bacteria showed higher cross-resistance to furazolidone (100%) followed by co-trimoxazole (47.5%) and enrofloxacin (11%). CONCLUSIONS: The maximum threshold of tetracycline resistance at 1024 μg mL-1 was observed in S. arlettae, Enterobacter spp., B. faecalis, and L. garvieae and tet(A) was the major determinant found in this study.202336958862
524760.9608Similar Levels of Antimicrobial Resistance in U.S. Food Service Ground Beef Products with and without a "Raised without Antibiotics" Claim. U.S. ground beef with "raised without antibiotics" (RWA) label claims are perceived as harboring fewer bacteria with antimicrobial resistance (AMR) than are found in conventional (CONV) ground beef with no such label claim. A total of 370 ground beef samples from CONV ( n = 191) and RWA ( n = 179) production systems were collected over 13 months from three food service suppliers. The following bacteria were cultured: Escherichia coli, tetracycline-resistant (TET(r)) E. coli, third-generation cephalosporin-resistant (3GC(r)) E. coli, Salmonella enterica, TET(r) S. enterica, 3GC(r) S. enterica, nalidixic acid-resistant S. enterica, Enterococcus spp., erythromycin-resistant Enterococcus spp., TET(r) Enterococcus spp., Staphylococcus aureus, and methicillin-resistant S. aureus. TET(r) E. coli was more frequently detected in CONV ground beef (CONV, 54.2%; RWA, 35.2%; P < 0.01), but supplier ( P < 0.01) and production system × suppler interaction ( P < 0.01) effects were also significant. Metagenomic DNA was isolated from each sample, and equal amounts of metagenomic DNA were pooled by supplier, month, and production system for 75 pooled samples (38 CONV, 37 RWA). The abundance of aac(6')-Ie-aph(2″)-Ia, aadA1, bla(CMY-2), bla(CTX-M), bla(KPC-2), erm(B), mecA, tet(A), tet(B), and tet(M) genes was assessed by quantitative PCR. The tet(A) (2.9-log(2)-fold change, P = 0.04) and tet(B) (5.6-log(2)-fold change) ( P = 0.03) genes were significantly more abundant in RWA ground beef. Phylogenetic analyses revealed that ground beef microbiomes differed more by supplier than by production system. These results were consistent with prior research suggesting antimicrobial use in U.S. beef cattle has minimal impact on the AMR of bacteria found in these products. These results should spur a reevaluation of assumptions regarding the impact of antimicrobial use during U.S. beef production on the AMR of bacteria in ground beef.201830476443
872370.9603Unraveling the Basis of Neonicotinoid Resistance in Whitefly Species Complex: Role of Endosymbiotic Bacteria and Insecticide Resistance Genes. Bemisia tabaci (whitefly) is one of the most detrimental agricultural insect pests and vectors of many plant viruses distributed worldwide. Knowledge of the distribution patterns and insecticide resistance of this cryptic species is crucial for its management. In this study, genetic variation of mitochondrial cytochrome oxidase subunit 1 (MtCoI) gene of B. tabaci was analyzed followed by a study of the infection profile of various endosymbionts in 26 whitefly populations collected from West Bengal, India. Phylogenetic analysis revealed Asia I as the major cryptic species (65.38%), followed by Asia II 5, China 3, and Asia II 7, which were diversified into 20 different haplotypes. In addition to the primary endosymbiont (C. poriera), each of the four whitefly species showed a variable population of three secondary endosymbionts, majorly Arsenophonus with the highest infection rate (73.07%), followed by Wolbachia and Rickettsia. Further phylogenetic analyses revealed the presence of two subgroups of Arsenophonus, viz., A1 and A2, and one each in Wolbachia (W1) and Rickettsia (R3). Resistance to thiamethoxam, imidacloprid, and acetamiprid insecticides was analyzed for a clear picture of pesticide resistance status. The highest susceptibility was noted toward thiamethoxam (LC(50) = 5.36 mg/L), followed by imidacloprid and acetamiprid. The whitefly population from Purulia and Hooghly districts bearing Asia II 7 and Asia II 5 cryptic species, respectively, shows maximum resistance. The differences in mean relative titer of four symbiotic bacteria among field populations varied considerably; however, a significant positive linear correlation was observed between the resistance level and relative titer of Arsenophonus and Wolbachia in the case of imidacloprid and thiamethoxam, while only Wolbachia was found in case of acetamiprid. Expression analysis demonstrated differential upregulation of insecticide resistance genes with Purulia and Hooghly populations showing maximally upregulated P450 genes. Moreover, thiamethoxam and imidacloprid resistance ratio (RR) showed a significant correlation with CYP6CM1, CYP6DZ7, and CYP4C64 genes, while acetamiprid RR correlated with CYP6CX1, CYP6DW2, CYP6DZ7, and CYP4C64 genes. Taken together, these findings suggested that P450 mono-oxygenase and symbiotic bacteria together affected whitefly resistance to neonicotinoids. Hence, a symbiont-oriented management programme could be a better alternative to control or delay resistance development in whitefly and can be used for pesticide clean-up in an agricultural field.202235814684
524680.9603Food Service Pork Chops from Three U.S. Regions Harbor Similar Levels of Antimicrobial Resistance Regardless of Antibiotic Use Claims. Pork products from animals "raised without antibiotics" (RWA) are assumed to harbor lower levels of antimicrobial resistance (AMR) than conventional (CONV) pork products with no claims regarding use of antimicrobial agents during production. A total of 372 pork chop samples from CONV (n = 190) and RWA (n = 182) production systems were collected over 13 months from three food service suppliers. The following bacteria were cultured: Escherichia coli, tetracycline-resistant (TET(r)) E. coli, third-generation cephalosporin-resistant (3GC(r)) E. coli, Salmonella enterica, TET(r) Salmonella, 3GC(r) Salmonella, nalidixic acid-resistant Salmonella, Enterococcus spp., TET(r) Enterococcus, erythromycin-resistant Enterococcus, Staphylococcus aureus, and methicillin-resistant S. aureus. Production system did not significantly impact the detection of cultured bacteria (P > 0.05). Metagenomic DNA was isolated from each sample, and equal amounts of metagenomic DNA were pooled by supplier, month, and production system for 75 pooled samples (38 CONV, 37 RWA). Quantitative PCR was used to assess the abundances of the following 10 AMR genes: aac(6')-Ie-aph(2″)-Ia, aadA1, bla(CMY-2), bla(CTX-M), bla(KPC-2), erm(B), mecA, tet(A), tet(B), and tet(M). For all 10 AMR genes, abundances did not differ significantly (P > 0.05) between production systems. These results suggest that use of antimicrobial agents during swine production minimally impacts the AMR of bacteria in pork chops.201931532250
134290.9603Prevalence, Toxin Genes, and Antibiotic Resistance Profiles of Bacillus cereus Isolates from Spices in Antalya and Isparta Provinces in Türkiye. Bacillus cereus is a pathogenic bacterium commonly found in nature and can produce toxins that cause food poisoning. This study aimed to detect the prevalence of B. cereus group bacteria in 50 unpackaged and 20 packaged spice samples frequently used as flavoring in Turkish cuisine, as well as investigate the presence of toxin genes and antibiotic resistance in the isolates. A total of 48 B. cereus group bacteria were isolated from 27 of 70 (38.57%) spice samples. The prevalence of B. cereus group bacteria in packaged (25%, 5/20) and unpackaged (44%, 22/50) spice samples did not differ significantly (P ˃ 0.05). All B. cereus group isolates were identified as B. cereus sensu stricto (B. cereus) using molecular methods. The hemolytic activity tests revealed that the most strains (44/48, 91.67%) are β-hemolytic. The distributions of toxin genes in isolates were investigated by PCR. It was determined that all isolates were identified to have 2-8 toxin genes, except B. cereus SBC3. The three most common toxin genes were found to be nheA (47/48, 97.92%), nheB (46/48, 95.83%), and entFM (46/48, 95.83%). All B. cereus isolates were susceptible to linezolid and vancomycin, while 35.42% (17/48) showed resistance to erythromycin. Multi-drug resistance (MDR) was detected in 8.3% (4/48) of B. cereus isolates, while 33.33% of the isolates showed multiple antibiotic resistance (MAR) index values higher than 0.2. The findings indicate that B. cereus may pose a health risk in packaged and unpackaged spices if present in high quantities. Therefore, the presence of B. cereus strains in both packaged and unpackaged spices should be monitored regarding consumer health and product safety.202338031610
3062100.9603Characterization of organotin-resistant bacteria from boston harbor sediments. Organotins are widely used in agriculture and industry. They are toxic to a variety of organisms including bacteria, although little is known of their physiology and ecology. Bacteria resistant to six organotins-tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT), and monophenyltin (MPT)-were isolated from Boston Harbor sediments, Massachusetts, USA. Bacteria resistant to each of the organotins, except DPT, were isolated directly from estuarine sediments. Viability of the organotin-resistant bacteria on serial transfer in the laboratory ranged from 80 to 91%. Each isolate was screened for resistance to the other organotins. All of 250 isolates were resistant to at least two organotins. No DPT-resistant isolates were found on initial isolation on DPT, although there was DPT resistance among the other organotin-resistant bacteria. Eighty percent of TBT-resistant bacteria were TPT-resistant, suggesting that antifouling paints containing TPT will not be a suitable substitute for TBT in paints designed to inhibit microbial biofilms. Debutylation reduced toxicity in some cases while dephenylation did not. Thus, even though trisubstituted organotins are generally believed to be more toxic than di- or monosubstituted organotins, this may not always be the case, and more than one mechanism of resistance may be involved. All the bacteria were resistant to at least six of eight heavy metals tested, suggesting that resistance to heavy metals may be associated with resistance to organotins.19989732471
3546110.9602Mitigation of tetracycline resistance genes in silage through targeted lactic acid bacteria inoculation. The dissemination of antibiotic resistance genes (ARGs) in silage ecosystems poses a critical challenge to ecological stability and public health security. This investigation focuses on tetracycline resistance genes (TRGs), the most prevalent subtype of ARGs in silage, employing a targeted selection strategy for lactic acid bacteria (LAB) inoculants. From 226 isolated LAB strains, four candidates (LP1-3: Lactiplantibacillus plantarum; LC1: Lacticaseibacillus paracasei) demonstrating superior growth kinetics (OD(600) > 1.6 within 24 h) and rapid acidification capacity (pH < 3.9 within 24 h) were selected. Strains LP3 and LC1 exhibited minimal intrinsic TRGs content. These four strains reduced (p < 0.001) pH, ammonia-N concentration, and coliform bacterial counts of stylo silage. Metagenomic analysis revealed that strains LP1-3 promoted Lactiplantibacillus dominance (0.709-0.975 vs. 0.379-0.509 in the control), while LC1 enhanced Lacticaseibacillus abundance (0.449-0.612 vs. 0.002-0.013 in the control). Ensiling process downregulated 367 and upregulated 227 ARGs. Inoculation with the four LAB strains further enhanced the suppression of ARGs. Among the top 30 TRGs, 22 were reduced by strains LP1-3 and 20 by LC1. Quantitative PCR results showed that strains LP1-3 decreased (p < 0.05) the contents of tetA and tetG during 30 days fermentation. Among the TRGs increased, tetA(60), tetB(58), tet(T) were positively correlated with Lactiplantibacillus spp., tetA(58), tetB(60), tetA(46), tetB(46), tet(43) were significantly correlated with Lacticaseibacillus spp. (R > 0.4, p < 0.001). In conclusion, the fermentation process induced substantial ARGs profile modifications, LAB-mediated microbiome engineering enables TRGs suppression, providing a scientific foundation for precision silage management strategies targeting antimicrobial resistance mitigation.202541038354
6153120.9601Isolation and characterization of aerobic, culturable, arsenic-tolerant bacteria from lead-zinc mine tailing in southern China. Bioremediation of arsenic (As) pollution is an important environmental issue. The present investigation was carried out to isolate As-resistant novel bacteria and characterize their As transformation and tolerance ability. A total of 170 As-resistant bacteria were isolated from As-contaminated soils at the Kangjiawan lead-zinc tailing mine, located in Hunan Province, southern China. Thirteen As-resistant isolates were screened by exposure to 260 mM Na(2)HAsO(4)·7H(2)O, most of which showed a very high level of resistance to As(5+) (MIC ≥ 600 mM) and As(3+) (MIC ≥ 10 mM). Sequence analysis of 16S rRNA genes indicated that the 13 isolates tested belong to the phyla Firmicutes, Proteobacteria and Actinobacteria, and these isolates were assigned to eight genera, Bacillus, Williamsia, Citricoccus, Rhodococcus, Arthrobacter, Ochrobactrum, Pseudomonas and Sphingomonas. Genes involved in As resistance were present in 11 of the isolates. All 13 strains transformed As (1 mM); the oxidation and reduction rates were 5-30% and 10-51.2% within 72 h, respectively. The rates of oxidation by Bacillus sp. Tw1 and Pseudomonas spp. Tw224 peaked at 42.48 and 34.94% at 120 h, respectively. For Pseudomonas spp. Tw224 and Bacillus sp. Tw133, the highest reduction rates were 52.01% at 48 h and 48.66% at 144 h, respectively. Our findings will facilitate further research into As metabolism and bioremediation of As pollution by genome sequencing and genes modification.201830446973
43130.9601Evaluation of transgenic 'Chardonnay' (Vitis vinifera) containing magainin genes for resistance to crown gall and powdery mildew. Magainins, short peptides with broad-spectrum antimicrobial activity in vitro, were assayed for their ability to confer resistance to pathogens in transgenic grapevines. Embryogenic cell suspensions of 'Chardonnay' (Vitis vinifera L.) were co-transformed by microprojectile bombardment with a plasmid carrying the npt-II gene and a second plasmid harboring either a natural magainin-2 (mag2) or a synthetic derivative (MSI99) gene. Magainin genes and the marker gene were driven by Arabidopsis ubiquitin-3 and ubiquitin-11 promoters, respectively. A total of 10 mag2 and 9 MSI99 regenerated lines were studied by Southern blot hybridization, which showed 1-6 transgene integration events into the plant genome. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed a variable range in transcription levels among mag2 and MSI99 lines. A positive correlation between number of integration events and transcription level was observed (p<0.05). Plants were acclimated and challenged in the greenhouse with either Agrobacterium vitis strains (bacterial crown gall pathogen) at 10(8) cfu/ml or Uncinula necator (fungal powdery mildew pathogen) at 10(5) conidia/ml for evaluation of disease resistance. A total of 6 mag2 and 5 MSI99 lines expressing the antimicrobial genes exhibited significant reductions of crown gall symptoms as compared to non-transformed controls. However, only two mag2 lines showed measurable symptom reductions in response to U. necator, but not strong resistance. Our results suggest that the expression of magainin-type genes in grapevines may be more effective against bacteria than fungi. Additional strategies to enhance transgene expression and the spectrum of resistance to grape diseases are suggested.200616475011
2338140.9601Characterization of disinfectant susceptibility profiles among clinical isolates of Acinetobacter baumannii in Ardabil, Iran. Antimicrobial disinfectants have been extensively used to control hospital-acquired infections worldwide. Prolonged exposure to bacteria could promote resistance to antimicrobial disinfectants. This study evaluated the antimicrobial activity of four commonly used disinfectants; triclosan, chlorhexidine digluconate, benzalkonium chloride, and formaldehyde against Acinetobacter baumannii clinical isolates. This study also determined the prevalence and association of efflux pumps encoding genes qacE, qacED1, emrA, and aceI with tolerance to disinfectants. A total of 100 A. baumannii isolates were included in the current study. The antimicrobial disinfectants' minimum inhibitory concentration (MIC) was determined using an agar dilution method. Genes involved in resistance to disinfectants were investigated by PCR method. The benzalkonium chloride MICs ranged between 32 and 128 μg mL-1, chlorhexidine digluconate 8-64 μg mL-1, triclosan 1-32 μg mL-1, and formaldehyde 128 μg mL-1. Overall, the highest MIC90 value was identified for formaldehyde (128 μg mL-1), followed by benzalkonium chloride and chlorhexidine digluconate (64 μg mL-1, each one) and triclosan (4 μg mL-1). In the present study, the qacE, qacED1, emrA, and aceI genes were found in 91%, 55%, 100%, and 88% of isolates, respectively. The qacG gene was not identified in our A. baumannii isolates. The qacED1 gene was associated with higher MICs for all disinfectants tested (P < 0.05), while the qacE and aceI genes were associated with higher MICs for benzalkonium chloride and chlorhexidine. This study indicated that triclosan is the most effective disinfectant against A. baumannii isolates.202338063878
7747150.9600Hydrothermal pre-treatment followed by anaerobic digestion for the removal of tylosin and antibiotic resistance agents from poultry litter. Hydrothermal pretreatment (HPT) followed by anaerobic digestion (AD) is an alternative for harvesting energy and removing organic contaminants from sewage sludge and animal manure. This study investigated the use, in an energetically sustainable way, of HPT and AD, alone or combined, to produce methane and remove tylosin and antimicrobial resistance genes (ARG) from poultry litter (PL). The results showed that HPT at 80 °C (HPT80), followed by single-stage AD (AD-1S), led to the production of 517.9 ± 4.7 NL CH(4) kg VS(-1), resulting in 0.11 kWh kg PL(-1) of electrical energy and 0.75 MJ kg PL(-1) of thermal energy, thus supplying 33.6% of the energy spent on burning firewood at a typical farm. In this best-case scenario, the use of HPT alone reduced tylosin concentration from PL by 23.6%, while the process involving HPT followed by AD-1S led to the removal of 91.6% of such antibiotic. The combined process (HPT80 + AD-1S), in addition to contributing to reduce the absolute and relative abundances of ARG ermB (2.13 logs), intI1 (0.39 logs), sul1 (0.63 logs), and tetA (0.74 logs), led to a significant removal in the relative abundance of tylosin-resistant bacteria present in the poultry litter.202336648713
5387160.9600Assessment of antibiotic susceptibility within lactic acid bacteria strains isolated from wine. Susceptibility to 12 antibiotics was tested in 75 unrelated lactic acid bacteria strains of wine origin of the following species: 38 Lactobacillus plantarum, 3 Lactobacillus hilgardii, 2 Lactobacillus paracasei, 1 Lactobacillus sp, 21 Oenococcus oeni, 4 Pediococcus pentosaceus, 2 Pediococcus parvulus, 1 Pediococcus acidilactici, and 3 Leuconostoc mesenteroides. The Minimal Inhibitory Concentrations of the different antibiotics that inhibited 50% of the strains of the Lactobacillus, Leuconostoc and Pediococcus genera were, respectively, the following ones: penicillin (2, < or =0.5, and < or =0.5 microg/ml), erythromycin (< or =0.5 microg/ml), chloramphenicol (4 microg/ml), ciprofloxacin (64, 8, and 128 microg/ml), vancomycin (> or =128 microg/ml), tetracycline (8, 2, and 8 microg/ml), streptomycin (256, 32, and 512 microg/ml), gentamicin (64, 4, and 128 microg/ml), kanamycin (256, 64, and 512 microg/ml), sulfamethoxazole (> or =1024 microg/ml), and trimethoprim (16 microg/ml). All 21 O. oeni showed susceptibility to erythromycin, tetracycline, rifampicin and chloramphenicol, and exhibited resistance to aminoglycosides, vancomycin, sulfamethoxazole and trimethoprim, that could represent intrinsic resistance. Differences were observed among the O. oeni strains with respect to penicillin or ciprofloxacin susceptibility. Antibiotic resistance genes were studied by PCR and sequencing, and the following genes were detected: erm(B) (one P. acidilactici), tet(M) (one L. plantarum), tet(L) (one P. parvulus), aac(6')-aph(2") (four L. plantarum, one P. parvulus, one P. pentosaceus and two O. oeni), ant(6) (one L. plantarum, and two P. parvulus), and aph(3')-IIIa (one L. plantarum and one O. oeni). This is the first time, to our knowledge, that ant(6), aph(3')-IIIa and tet(L) genes are found in Lactobacillus and Pediococcus strains and antimicrobial resistance genes are reported in O. oeni strains.200616876896
8476170.9600Identification of a Major QTL (qRRs-10.1) That Confers Resistance to Ralstonia solanacearum in Pepper (Capsicum annuum) Using SLAF-BSA and QTL Mapping. The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt (BW), a major disease of pepper (Capsicum annuum). The genetic basis of resistance to this disease in pepper is not well known. This study aimed to identify BW resistance markers in pepper. Analysis of the dynamics of bioluminescent R. solanacearum colonization in reciprocal grafts of a resistant (BVRC 1) line and a susceptible (BVRC 25) line revealed that the resistant rootstock effectively suppressed the spreading of bacteria into the scion. The two clear-cut phenotypic distributions of the disease severity index in 440 F2 plants derived from BVRC 25 × BVRC 1 indicated that a major genetic factor as well as a few minor factors that control BW resistance. By specific-locus amplified fragment sequencing combined with bulked segregant analysis, two adjacent resistance-associated regions on chromosome 10 were identified. Quantitative trait (QTL) mapping revealed that these two regions belong to a single QTL, qRRs-10.1. The marker ID10-194305124, which reached a maximum log-likelihood value at 9.79 and accounted for 19.01% of the phenotypic variation, was located the closest to the QTL peak. A cluster of five predicted R genes and three defense-related genes, which are located in close proximity to the significant markers ID10-194305124 or ID10-196208712, are important candidate genes that may confer BW resistance in pepper.201931771239
7756180.9599Mitigation of antibiotic resistance: the efficiency of a hybrid subsurface flow constructed wetland in the removal of resistant bacteria in wastewater. This research investigates the effectiveness of a lab-scale hybrid subsurface flow constructed wetland (HSSFCW) for removing wastewater contaminants, including antibiotic-resistant bacteria (ARB), genes (ARGs) and antibiotics. The results suggested that HSSFCW demonstrated a high removal efficiency for COD (89%) and BOD (88.9%), while lower efficiencies were observed for salts, TDS, EC, and TKN. Further, various bacteria such as Enterobacter cloacae, Serratia liquefaciens and Serratia odorifera were detected in the plant rhizosphere, while Acinetobacter baumanii and Staphylococcus spp. were identified as biofilm formers on the wetland media. The mean removal efficiency of 70.44, 65.99, 70.66 and 51.49% was observed for total heterotrophic bacteria; Cefixime (Cef)-, Ciprofloxacin (Cip)-, and Linezolid (Lzd)-resistant bacteria. Upon chlorination of effluent samples, Cef-, Cip- and Lzd-resistant bacteria were effectively inactivated at 30, 15 and 7.5 mg Cl(2) min/L, respectively. The wetland achieved a removal efficiency of 83.85% for Cip and 100% for Lzd at week 12 with p = 0.040 and p < 0.001, respectively. Further, a log reduction of 0.66 for 16S, 0.82 for blaTEM, 0.61 for blaCTX, and 0.48 for blaOXA was observed. Thus, HSSFCW was observed to be efficient in removing organic contaminants, ARBs, ARGs and antibiotics from domestic wastewater and can be upgraded under natural environments.202540536145
1487190.9599Potential impact of a microarray-based nucleic acid assay for rapid detection of Gram-negative bacteria and resistance markers in positive blood cultures. We evaluated the Verigene Gram-negative blood culture (BC-GN) test, a microarray that detects Gram-negative bacteria and several resistance genes. A total of 102 positive blood cultures were tested, and the BC-GN test correctly identified 97.9% of the isolates within its panel. Resistance genes (CTX-M, KPC, VIM, and OXA genes) were detected in 29.8% of the isolates, with positive predictive values of 95.8% (95% confidence interval [CI], 87.7% to 98.9%) in Enterobacteriaceae and 100% (95% CI, 75.9% to 100%) in Pseudomonas aeruginosa and negative predictive values of 100% (95% CI, 93.9% to 100%) and 78.6% (95% CI, 51.0% to 93.6%), respectively.201424478405