Protective effect of Limosilactobacillus fermentum HFY06 on dextran sulfate sodium-induced colitis in mice.

Ulcerative colitis is one of the main gastrointestinal diseases that threaten human health. This study investigated the effect of Limosilactobacillus fermentum HFY06 (LF-HFY06) on dextran sulfate sodium (DSS)-induced murine colitis. The protective effect of LF-HFY06 was evaluated by examining the length and histopathological sections of colon, related biochemical indicators, and genes related to inflammation. Direct and microscopic observations showed that LF-HFY06 increased the length of the colon and ameliorated the pathological damage induced by DSS. The biochemical indicators showed that LF-HFY06 enhanced the activities of antioxidant enzymes total superoxide dismutase (T-SOD) and catalase (CAT) in serum, while reducing the level of malondialdehyde (MDA). It was also observed that the serum inflammatory cytokines levels of tumor necrosis factor-α (TNF-α), interferon (IFN)-γ, interleukin (IL)-1ß, IL-6, and IL-12 were decreased, and the anti-inflammatory cytokine IL-10 level was increased. The qPCR experiment revealed that LF-HFY06 downregulated the mRNA expression levels of nuclear factor-κB-p65 (Rela), Tnf, Il 1b, Il 6, and prostaglandin-endoperoxide synthase 2 (Ptgs2) in colon tissues, and upregulated the mRNA expression of NF-κB inhibitor-α (Nfkbia) and Il 10. These data indicated that LF-HFY06 inhibited inflammation through the NF-κB signaling pathway to prevent the occurrence and development of colitis. This research demonstrates that probiotics LF-HFY06 have the potential to prevent and treat colitis.

Prophylactic effect of Lactobacillus plantarum KSFY06 on HCl/ethanol-induced gastric injury in mice.

The present study was conducted to determine the prophylactic effect of Lactobacillus plantarum KSFY06 (LP-KSFY06) on HCl/ethanol-induced gastric injury in Kunming mice. The experimental mice were allocated into six groups: the normal group, HCl/ethanol treated group, HCl/ethanol + ranitidine treated group, HCl/ethanol + Lactobacillus delbrueckii subsp. Bulgaricus (LB) treated group, HCl/ethanol + low concentration of Lactobacillus plantans KSFY06 (LP-KSFY06-L) treated group, and HCl/ethanol + high concentration of Lactobacillus plantans KSFY06 (LP-KSFY06-H) treated group. The changes in daily body weight and food intake of the mice in the HCl/ethanol + LP-KSFY06-H treated group were the closest to those of the HCl/ethanol + ranitidine treated and normal groups. LP-KSFY06 significantly inhibited the formation of gastric mucosal lesions, reduced the area of gastric lesions, inhibited gastric-juice secretion, and increased pH compared with the HCl/ethanol treated group. After the treatment, the serum interleukin-6 (IL)-6, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ levels and the gastric-tissue IL-6 and IL-12 levels in the LP-KSFY06 (including LP-KSFY06-L and LP-KSFY06-H) group decreased compared with those in the HCl/ethanol treated group. The level of serum and gastric tissue malondialdehyde was lower and the nitric oxide, total superoxide dismutase, and glutathione activities in the LP-KSFY06 treated mice were higher than those in the HCl/ethanol treated mice. Quantitative polymerase chain reaction analysis and western blot analysis showed that LP-KSFY06 increased the mRNA and protein expression of the epidermal growth factor, epidermal growth factor receptor, vascular endothelial growth factor, inhibitor kappaB-α, neuronal nitric oxide synthase, and endothelial NOS and reduced the mRNA and protein expression of nuclear factor kappaB, inducible NOS, cyclooxygenase-2, TNF-α, and IL-1ß in gastric tissues compared with the HCl/ethanol treated mice. These experimental results showed that a high concentration (1.0 × 109 CFU per kg B.W.) of LP-KSFY06 had a stronger effect on preventing gastric injury than a low concentration (1.0 × 108 CFU per kg B.W.) of LP-KSFY06. These results suggest that LP-KSFY06 has a potential probiotic effect in preventing gastric injury.

Raw Bowl Tea (Tuocha) Polyphenol Prevention of Nonalcoholic Fatty Liver Disease by Regulating Intestinal Function in Mice.

A high-fat diet-induced C57BL/6N mouse model of non-alcoholic fatty liver disease (NAFLD) was established. The effect and mechanism of Raw Bowl Tea polyphenols (RBTP) on preventing NAFLD via regulating intestinal function were observed. The serum, liver, epididymis, small intestine tissues, and feces of mice were examined by biochemical and molecular biological methods, and the composition of RBTP was analyzed by HPLC assay. The results showed that RBTP could effectively reduce the body weight, liver weight, and liver index of NAFLD mice. The serum effects of RBTP were: (1) decreases in alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), D-lactate (D-LA), diamine oxidase (DAO), lipopolysaccharide (LPS), and an increase of high density lipoprotein cholesterol (HDL-C) levels; (2) a decrease of inflammatory cytokines such as interleukin 1 beta (IL-1ß), interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α), and interferon gamma (INF-γ); (3) a decrease the reactive oxygen species (ROS) level in liver tissue; and (4) alleviation of pathological injuries of liver, epididymis, and small intestinal tissues caused by NAFLD and protection of body tissues. qPCR and Western blot results showed that RBTP could up-regulate the mRNA and protein expressions of LPL, PPAR-α, CYP7A1, and CPT1, and down-regulate PPAR-γ and C/EBP-α in the liver of NAFLD mice. In addition, RBTP up-regulated the expression of occludin and ZO-1, and down-regulated the expression of CD36 and TNF-α in the small intestines of NAFLD mice. Studies on mice feces showed that RBTP reduced the level of Firmicutes and increased the minimum levels of Bacteroides and Akkermansia, as well as reduced the proportion of Firmicutes/Bacteroides in the feces of NAFLD mice, which play a role in regulating intestinal microecology. Component analysis showed that RBTP contained seven polyphenolic compounds: Gallic acid, (-)-epigallocatechin, catechin, L-epicatechin, (-)-epigallocatechin gallate, (-)-gallocatechin gallate, and (-)-epicatechin gallate (ECG), and high levels of caffeine, (-)-epigallocatechin (EGC), and ECG. RBTP improved the intestinal environment of NAFLD mice with the contained active ingredients, thus playing a role in preventing NAFLD. The effect was positively correlated with the dose of 100 mg/kg, which was even better than that of the clinical drug bezafibrate.

Effects of Lactobacillus plantarum CQPC01-fermented soybean milk on activated carbon-induced constipation through its antioxidant activity in mice.

A newly found strain, Lactobacillus plantarum CQPC01 (LP-CQPC01), was used for soybean milk fermentation, and its effects against constipation were determined. LP-CQPC01-FSM (LP-CQPC01-fermented soybean milk) was found to have six kinds of soybean isoflavones; the isoflavones of LP-CQPC01-FSM were more than those of Lactobacillus bulgaricus-fermented soybean milk (LB-FSM) and unfermented soybean milk (U-FSM). Animal experiment showed that the MTL, Gas, ET, AchE, SP, VIP, and GSH levels in the constipated mice were increased; however, the SS, MPO, NO, and MDA levels in the constipated mice were reduced by soybean milk treatment. Further, LP-CQPC01-FSM increased the mRNA and protein expression of Cu/Zn-SOD, Mn-SOD, CAT, c-Kit, SCF, and GDNF and reduced the expression of TRPV1 and NOS relative to those of the mice with untreated constipation. LP-CQPC01 could be used as a new starter to produce high-quality soybean milk, which might be used as a functional drink.

Preventive Effect of Small-Leaved Kuding Tea (Ligustrum robustum (Roxb.) Bl.) Polyphenols on D-Galactose-Induced Oxidative Stress and Aging in Mice.

Small-leaved Kuding tea is a traditional Chinese tea that is rich in polyphenols. In the current study, we investigated the preventive effect of small-leaved Kuding tea (SLKDT) on D-galactose-induced oxidative aging in mice. Changes in serum, skin, liver, and spleen of experimental animals were determined using biochemical and molecular biology techniques. Biochemical analysis demonstrated that polyphenol extract of SLKDT (PSLKDT) improved the indices of the thymus, brain, heart, liver, spleen, and kidney function in model mice. PSLKDT prevented a decrease in the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione (GSH) as well as an increase in nitric oxide (NO) and malondialdehyde (MDA) levels in serum, liver, and spleen. Pathological assessment also showed that PSLKDT reduced oxidative damage induced by D-galactose in skin, liver, and spleen. We further found that PSLKDT upregulated neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), Cu/Zn-SOD, Mn-SOD, catalase (CAT), heme oxygenase-1 (HO-1), nuclear factor (nuclear factor-erythroid 2 related factor 2 (Nrf2), γ-glutamylcysteine synthetase (γ-GCS), and NAD(P)H dehydrogenase [quinone] 1 (NQO1) mRNA expression and downregulated inducible nitric oxide synthase (iNOS) mRNA expression. Protein levels of SOD1 (Cu/Zn-SOD), SOD2 (Mn-SOD), CAT, GSH1 (γ-glutamate-cysteine ligase), and GSH2 (glutathione synthetase) in the liver and spleen were also increased by PSLKDT treatment. Collectively, these results indicate that PSLKDT is effective in preventing D-galactose-induced oxidative aging in mice, and its efficacy is significantly higher than antioxidant vitamin C. Because PSLKDT is a potent antioxidant and antiaging polyphenol, Kuding tea rich in PSLKDT should be considered an ideal drink with antioxidative and antiaging effects.

Wu Shan Shen Cha (Malus asiatica Nakai. Leaves)-Derived Flavonoids Alleviate Alcohol-Induced Gastric Injury in Mice via an Anti-Oxidative Mechanism.

Wu Shan Shen Cha is the leaf of Malus asiatica Nakai., a special type of tea that is consumed in the same way as green tea. To study the effect of Wu Shan Shen Cha-derived flavonoids (WSSCF) on lesions in the stomach, a 15% hydrochloric acid-95% ethanol (volume ratio 4:6) solution was used to induce gastric injury in mice. The degree of gastric injury was assessed using tissue specimens, and the effects of WSSCF on the serum levels of antioxidant enzymes were investigated. The results showed that WSSCF could alleviate the damage of the gastric mucosa and gastric wall caused by the hydrochloric acid-ethanol solution, decrease the tissue and serum levels of malondialdehyde (MDA) in mice with gastric injury, and increase the serum levels of superoxide dismutase (SOD) and glutathione (GSH). The results of quantitative polymerase chain reaction (qPCR) showed that WSSCF could increase the mRNA expression of Mn-SOD, Cu/Zn-SOD, catalase (CAT), endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) in tissue specimens from mice with gastric injury and decrease the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). At the same time, the results of the high concentration of WSSCF (WSSCFH) group were closer to those of the drug (ranitidine) treatment group. Wu Shan Shen Cha-derived flavonoids had a good antioxidant effect, so as to play a preventive role in alcoholic gastric injury.

Preventive Effect of Anji White Tea Flavonoids on Alcohol-Induced Gastric Injury through Their Antioxidant Effects in Kunming Mice.

Anji white tea (Camellia sinensis) is a traditional Chinese tea beverage, which is classified as green tea and contains an abundant amount of flavonoids. In this study, the preventive effect of Anji white tea flavonoids (AJWTFs) on ethanol/hydrochloric acid-induced gastric injury in mice was evaluated. The serum and gastric tissues of mice were analyzed using a biochemical kit and by quantitative polymerase chain reaction (qPCR). Observation of the appearance of the stomach indicated that AJWTFs could effectively reduce the area of gastric injury caused by ethanol/hydrochloric acid, and the inhibition rate of AJWTF on gastric injury increased with an increase in AJWTF concentration. The Anji white tea flavonoids could also reduce the volume and pH of gastric juice in mice with gastric injury. Biochemical results showed that AJWTFs could increase the superoxide dismutase (SOD) and glutathione (GSH) activities, as well as decrease the malondialdehyde (MDA) level, in the serum and liver of mice with gastric injury. Pathological observation confirmed that AJWTFs could inhibit the tissue damage caused by ethanol/hydrochloric acid in the stomach of mice. Further qPCR experiments also showed that AJWTFs could inhibit the decreases in neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), copper/zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT), and the increase in inducible nitric oxide synthase (iNOS) expression in the gastric tissue of mice caused by gastric injury. As observed, AJWTFs exerted a good preventive effect on alcohol-induced gastric injury in mice induced by ethanol/hydrochloric acid, and the effect is close to that of ranitidine. Anji white tea flavonoids present good antioxidant effect, which allows them to effectively prevent alcoholic gastric injury and be used as biologically active substances with a broad range of applications.

Preventive Effect of Lactobacillus fermentum CQPC08 on 4-Nitroquineline-1-Oxide Induced Tongue Cancer in C57BL/6 Mice.

Lactobacillus fermentum CQPC08 (LF-CQPC08) is a newly discovered strain of bacteria isolated and identified from traditional pickled vegetables in Sichuan, China. We used 4-nitroquinoline 1-oxide to establish an experimental tongue cancer mouse model to evaluate the preventive effect of LF-CQPC08 on tongue cancer in vivo. Lactobacillus delbruechii subsp. bulgaricus, is a common commercial strain and is used as a positive control to compare the effect with LF-CQPC08. The preventive strength and mechanism of LF-CQPC08 on tongue cancer were determined by measuring the biochemical indicators in mouse serum and tissues. Our results showed LF-CQPC08 inhibits the decline of splenic index, thymus index, percentage of phagocytic macrophages, and phagocytic index effectively. LF-CQPC08 also increased levels of mouse serum granulocyte-colony stimulating factor (G-CSF), granulocyte-macrophage-CSF (GM-CSF), immunoglobulin (Ig)G, IgM levels of serum interleukin (IL)-4, IL-12, tumor necrosis factor-alpha, and interferon-gamma levels, thereby inhibiting the decline in immunity caused by tongue cancer. It also increased the activity levels of superoxide dismutase and glutathione peroxidase and decreased the levels of malondialdehyde in the tissues of the tongue cancer mouse model, thereby suppressing the oxidative stress damage in the tissue caused by tongue cancer. Through quantitative PCR, LF-CQPC08 upregulated the mRNA expression of nuclear factor-erythroid 2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), glutathione-S-transferases-π (GST-π), and Bcl-2-associated X protein (Bax), and downregulated the mRNA expression of p53, p63, p73, phosphatase and tensin homolog (PTEN), B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xL) in the tongue tissues of the tongue cancer mouse. These results indicated that LF-CQPC08 reduced the influence of tongue cancer on the immune system and oxidative balance and improved the immunity and enhanced antioxidant capacity of the mouse model, thereby preventing tongue cancer. LF-CQPC08 could be used as a microbial resource with a preventive effect on tongue cancer.

Protective Effects of Ligustroflavone, an Active Compound from Ligustrum lucidum, on Diabetes-Induced Osteoporosis in Mice: A Potential Candidate as Calcium-Sensing Receptor Antagonist.

Ligustroflavone is one major compound contained in active fraction from Fructus Ligustri Lucidi (the fruit of Ligustrum lucidum), which could regulate parathyroid hormone (PTH) levels and improve calcium balance by acting on calcium-sensing receptors (CaSR). This study aimed to explore the potency of ligustroflavone as a CaSR antagonist and its protective effects against diabetic osteoporosis in mice. LF interacted well with the allosteric site of CaSR shown by molecular docking analysis, increased PTH release of primary parathyroid gland cells and suppressed extracellular calcium influx in HEK-293 cells. The serum level of PTH attained peak value at 2 h and maintained high during the period of 1 h and 3 h than that before treatment in mice after a single dose of LF. Treatment of diabetic mice with LF inhibited the decrease in calcium level of serum and bone and the enhancement in urinary calcium excretion as well as elevated circulating PTH levels. Trabecular bone mineral density and micro-architecture were markedly improved in diabetic mice upon to LF treatment for 8 weeks. LF reduced CaSR mRNA and protein expression in the kidneys of diabetic mice. Taken together, ligustroflavone could transiently increase PTH level and regulate calcium metabolism as well as prevent osteoporosis in diabetic mice, suggesting that ligustroflavone might be an effective antagonist on CaSR.

Preventive Effect of Blueberry Extract on Liver Injury Induced by Carbon Tetrachloride in Mice.

The blueberry is a common fruit that is rich in nutritional value and polyphenol substances. In this study, the blueberry polyphenol content in extract was analysed by spectrophotometry. The results showed that the blueberry polyphenol content in the extract reached 52.7%. A mouse model of liver injury induced by carbon tetrachloride (CCl4) was established to study the preventive effect of blueberry extract (BE) on liver injury in mice and the experimental animals were examined using biochemical and molecular biological methods. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are important clinical liver function indicators; the changes of triglyceride (TG) and total cholesterol (TC) are observed after liver injury; interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) are important inflammatory indexes; superoxide dismutase (SOD) activity and thiobarbituric acid reactive substances (TBARS) are important changes of oxidative stress indexes. The in vivo animal experiment results showed that BE decreased the liver index of mice with liver injury, BE could reduce the AST, ALT, TG and TC levels and also could reduce the serum cytokine IL-6, TNF-α and IFN-γ levels in mice with liver injury. Moreover, BE increased the SOD activity and decreased the TBARS level in the gastric tissues of mice with liver injury. After treatment with the highest concentration of BP in liver injury mice, these levels returned close to those obtained after treatment with the standard drug of silymarin. Detection of messenger RNA (mRNA) in liver tissue showed that BE upregulated the Cu/Zn-SOD, Mn-SOD and chloramphenicol acetyltransferase (CAT) expression levels and downregulated cyclooxygenase (COX)-2 expression. The effect of BE on mice with liver injury was positively correlated with the BE concentration and was similar to that of silymarin, which is a drug for liver injury, suggesting that BE had a good preventive effect on liver injury. Thus, BE rich in polyphenols is a bioactive substance with value for development and utilization.

Preventive Effect of Alkaloids from Lotus plumule on Acute Liver Injury in Mice.

Lotus plumule is a traditional Chinese food that can be used as a beverage. In this study, three kinds of Lotus plumules from different regions of China were selected to observe the preventive effects of extracted alkaloids on CCl4-induced liver injuries. Animal experiments revealed that alkaloids extracted from Lotus plumules decreased the serum AST (aspartate aminotransferase), ALT (alanine aminotransferase), and TBIL (total bilirubin) levels, enhanced SOD (superoxide dismutase) activity, and reduced MDA (malondialdehyde) level in the liver tissues of mice with liver injury. H&E observation confirmed that alkaloids from Lotus plumules could alleviate CCl4-induced injuries of liver tissues and inhibit the inflammatory effect on hepatocytes. Further qPCR experiments also demonstrated that alkaloids from Lotus plumules upregulated the expression of IκB-α (inhibitor of NF-κB alpha), Cu/Zn-SOD (copper/zinc superoxide dismutase), Mn-SOD (manganese superoxide dismutase), and CAT (catalase) mRNA and downregulated TNF-α (tumor necrosis factor alpha) and NF-κB (nuclear factor kappa B) expression in the liver tissues of mice with liver injury. All three kinds of alkaloids from Lotus plumules could prevent CCl4-induced liver injuries by regulating the levels of oxidative stress and inflammation in mice, and the therapeutic effect was comparable to that of silymarin, the medicine commonly used in the treatment of liver diseases. In summary, alkaloids from Lotus plumules contain bioactive substances with hepatic protective efficacy and possess potential application value in the field of functional food.

Co-occurrence of biofilm formation and quinolone resistance in Salmonella enterica serotype typhimurium carrying an IncHI2-type oqxAB-positive plasmid.

The objective of this study was to investigate the co-occurrence of biofilms and quinolone resistance in Salmonella enterica serotype Typhimurium mediated by IncHI2-type oqxAB-positive plasmids. Among the 40 Salmonella strains, we found that 27 isolates formed biofilms and displayed identical multidrug-resistance profiles to ciprofloxacin, doxycycline, sulfamethoxazole-trimethoprim, ampicillin and streptomycin, based on biofilm formation assays and antimicrobial susceptibility testing. In particular, a single S. Typhimurium isolate named SC523 produced the thickest biofilms and exhibited the highest-level resistance (MIC = 8 µg/mL) to ciprofloxacin compared to those of the other isolates. The detection of known plasmid-mediated quinolone resistance (PMQR) genes and point mutations in the quinolone resistance-determining region (QRDR) by PCR assay showed that oqxAB genes were present in 27 biofilm-positive isolates. Conjugation experiments, S1-pulse-field gel electrophoresis and biofilm formation assays demonstrated that the conjugative plasmid that encoded biofilms and quinolone resistance in Salmonella SC523 could be transferred to a recipient with a frequency of 4.7 × 10-3 per recipient cell. The results of PCR-based replicon typing (PBRT) showed that the IncHI2-type plasmids accounted for 100% of the biofilm-oqxAB-positive isolates and transconjugants. The sequence analysis of Salmonella SC523 confirmed that the oqxAB cassette and fourteen DNA transfer genes in the IncHI2-type oqxAB-positive conjugative plasmid were genetically responsible for the phenotypic quinolone resistance and biofilm formation. The conclusion is that the IncHI2-type plasmid in S. Typhimurium isolate from chicken farm was identified and sequenced, which contained oqxAB and tra/trh and encoded quinolone resistance and biofilms, and could be transferred to recipients through conjugation. Notably, the prevalence of IncHI2-type biofilm-oqxAB-positive plasmids in animal-origin Salmonella poses a threat to public health, as these Salmonella from poultry farms show a decreased susceptibility to quinolones and could spread to humans.

Colocation of the Polymyxin Resistance Gene mcr-1 and a Variant of mcr-3 on a Plasmid in an Escherichia coli Isolate from a Chicken Farm.

A colistin-resistant Escherichia coli isolate from a commercial poultry farm in China carried two colistin resistance genes, mcr-1 and variant of mcr-3, in an IncP plasmid. The variant of the mcr-3 gene, named mcr-3.11, encoded two amino acid substitutions compared with the mcr-3 gene. A novel genetic structure, ISKpn40-mcr-3-dgkA-ISKpn40, might be the key element mediating the translocation of mcr-3 through the formation of a circular form. The mcr-1 and mcr-3 genes, which are colocated on a plasmid, might pose a huge threat to public health.

Tn6450, a Novel Multidrug Resistance Transposon Characterized in a Proteus mirabilis Isolate from Chicken in China.

A novel 65.8-kb multidrug resistance transposon, designated Tn6450, was characterized in a Proteus mirabilis isolate from chicken in China. Tn6450 contains 18 different antimicrobial resistance genes, including cephalosporinase gene blaDHA-1 and fluoroquinolone resistance genes qnrA1 and aac(6')-Ib-cr It carries a class 1/2 hybrid integron composed of intI2 and a 3' conserved segment of the class 1 integron. Tn6450 is derived from Tn7 via acquisition of new mobile elements and resistance genes.

Prevalence, Antimicrobial Resistance, and Relatedness of Salmonella Isolated from Chickens and Pigs on Farms, Abattoirs, and Markets in Sichuan Province, China.

This study aims at investigating the distribution, antimicrobial resistance, and genetic relationship of Salmonella isolated from 18 farms, their downstream abattoirs, and markets of chickens and pigs in Sichuan province, China. A total of 193 Salmonella isolates were identified from 693 samples with an isolation rate of 26.27% (88/335) in chickens and 29.33% (105/358) in pigs. Salmonella was isolated more frequently in abattoirs and markets than from farms. Serotypes were determined according to the White-Kauffmann-Le Minor scheme and 16 different serotypes were identified, with Derby being the most common, followed by Typhimurium and Meleagridis. Antimicrobial resistance phenotypes and genotypes were studied by using the disk diffusion method and polymerase chain reaction (PCR) amplification, respectively. Overall, 44.04% (n = 85) of all isolates were multidrug resistant (MDR) and resistance to nalidixic acid (51.30%) was the most frequently observed. blaCTX-M-55 was the most prevalent extended-spectrum ß-lactamases gene, and polymyxin resistance gene mcr-1 was present in strains with various serotypes. Multilocus sequence typing indicated that sequence type (ST) had a close relationship with serotype, and 34.20% of all strains were ST40, which was the most prevalent. The unweighted pair group method with arithmetic means (UPGMA) dendrogram of pulsed-field gel electrophoresis showed that Salmonella isolates belonging to the same serovar from different parts of the production chain were highly genetic related, indicating that Salmonella as well as resistance genes could potentially be transmitted from farms to markets. Our study highlights the fact that Salmonella isolates from chicken and pig production chain were frequently exhibiting MDR profiles, and the dissemination of MDR Salmonella from farm to market could pose significant threats to food safety and public health.

Emergence of Salmonella enterica serovar Indiana and California isolates with concurrent resistance to cefotaxime, amikacin and ciprofloxacin from chickens in China.

The aim of this study was to investigate the prevalence and characterization of Salmonella concerning the poultry industry in China. A total of 170 non-duplicate Salmonella isolates were recovered from the 1540 chicken samples. Among the Salmonella isolates from chickens, the predominant serovars were S. enterica serovar Enteritidis (S. Enteritidis) (49/170, 28.8%), S. enterica serovar Indiana (S. Indiana) (37/170, 21.8%) and S. enterica serovar California (S. California) (34/170, 20.0%). High antimicrobial resistance was observed for ciprofloxacin (68.2%), amikacin (48.2%) and cefotaxime (44.7%). Of particular concerns were the 18 S. Indiana and 17 S. California isolates, which were concurrently resistant to cefotaxime, amikacin and ciprofloxacin. The blaCTX-M genes, 16S rRNA methylase genes (armA, rmtD or rmtC) and five plasmid-mediated quinolone resistance (PMQR) determinants (aac(6')-Ib-cr, oqxAB, qnrB, qepA and qnrD) were identified in 18 S. Indiana and 17 S. California isolates. To clarify their genetic correlation, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were further conducted. PFGE profiles showed that the majority of S. Indiana and S. California isolates were clonally unrelated with a standard cut-off of 85%. The results of MLST demonstrated that ST17 and ST40 were the most common ST types in S. Indiana and S. California isolates, respectively. Our findings indicated that the multiple antibiotic resistant S. Indiana and S. California isolates were widespread in chicken in China and might pose a potential threat to public health.

Colocation of the Multiresistance Gene cfr and the Fosfomycin Resistance Gene fosD on a Novel Plasmid in Staphylococcus arlettae from a Chicken Farm.

The novel 63,558-bp plasmid pSA-01, which harbors nine antibiotic resistance genes, including cfr, erm(C), tet(L), erm(T), aadD, fosD, fexB, aacA-aphD, and erm(B), was characterized in Staphylococcus arlettae strain SA-01, isolated from a chicken farm in China. The colocation of cfr and fosD genes was detected for the first time in an S. arlettae plasmid. The detection of two IS431-mediated circular forms containing resistance genes in SA-01 suggested that IS431 may facilitate dissemination of antibiotic resistance genes.

A novel type 1/2 hybrid IncC plasmid carrying fifteen antimicrobial resistance genes recovered from Proteus mirabilis in China.

IncC plasmids are of great concern as vehicles of broad-spectrum cephalosporins and carbapenems resistance genes blaCMY and blaNDM. The aim of this study was to sequence and characterize a multidrug resistance (MDR) IncC plasmid (pPm14C18) recovered from Proteus mirabilis. pPm14C18 was identified in a CMY-2-producing P. mirabilis isolate from chicken in China in 2014, and could be transferred to Escherichia coli conferring an MDR phenotype. Whole genome sequencing confirmed pPm14C18 was a novel type 1/2 hybrid IncC plasmid 165,992bp in size, containing fifteen antimicrobial resistance genes. It harboured a novel MDR mosaic region comprised of a hybrid Tn21tnp-pDUmer, in which blaCTX-M-65, dfrA32 and ereA were firstly reported in IncC plasmid. Phylogenetic relationship reconstruction based on the nucleotide sequences of the 52 IncC backbones showed all type 1 IncC plasmids were clustered into one clade, and then merged with pPm14C18 and finally with the type 2 IncC plasmids and another type 1/2 hybrid IncC plasmid pYR1. The MDR IncC plasmids in P. mirabilis of animal origin might threaten public health, which should be drawn more attention.

Characterization of pHeBE7, an IncFII-type virulence-resistance plasmid carrying blaCTX-M-98b, blaTEM-1, and rmtB genes, detected in Escherichia coli from a chicken isolate in China.

Recently, a novel variant of the CTX-M enzyme, CTX-M-98, was detected in Escherichia coli isolates from food animals. However, few plasmids carrying blaCTX-M-98 have been fully characterized. In this study, we sequenced the complete pHeBE7 plasmid, an 86,015-bp plasmid that contains the blaCTX-M-98b, blaTEM-1, rmtB, and traT genes, using whole-genome sequencing. The backbone of pHeBE7 shows a high similarity (>99%) to pMC-NDM, which carries the blaNDM-1 gene, however its mosaic regions remain relatively unique among sequenced plasmids. We discovered that a typical ISEcp1-blaCTX-M-IS903 element in the mosaic region harbors the blaCTX-M-98b gene. Conjugation and growth competition assays indicate that pHeBE7 can be easily transmitted and that it confers a limited fitness cost to the recipient cell. The genetic characterization of pHeBE7 may improve our knowledge of how antibiotic resistance disseminates in enterobacteria.

Colistin Resistance Gene mcr-1 and Its Variant in Escherichia coli Isolates from Chickens in China.

The mcr-1 gene was detected in 5.11% (58/1136) of Escherichia coli isolates of chicken origin from 13 provinces in China. A novel mcr-1 variant, named mcr-1.3, encoding an Ile-to-Val functional variant of MCR-1 was identified in a sequence type 155 (ST155) strain. An mcr-1.3-containing IncI2 plasmid, pHeN867 (60,757 bp), was identified. The transfer of pHeN867 led to a 32-fold increase in the MIC of colistin in the recipient, exhibiting an effect on colistin resistance that was similar to that of mcr-1.