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lsa (E) is a pleuromutilin, lincosamide, and streptogramin A (PLSA phenotype) resistance gene that was first described in S. aureus and was thought to have been transferred from Enterococcus sp. This study aimed to elucidate the prevalence of the lsa (E) gene among E. faecium isolates at a tertiary teaching hospital and to evaluate the transferability of the lsa (E) gene from E. faecium to S. aureus in vitro. A total of 96 E. faecium strains isolated from one hospital in Beijing in 2013 were analysed for quinupristin-dalfopristin (QDA) resistance genes, and multilocus sequence typing (MLST) was performed. The transferability of QDA resistance between ten E. faecium strains and four S. aureus strains was determined by filter mating. Genome sequencing of the transconjugant was performed. A total of 46 E. faecium isolates (46/96, 47.92%) tested positive for lsa (E), while two isolates (2/96, 2.08%) tested positive for lsa (A). Thirty-six lsa (E)-positive strains (36/46, 78.3%) belonged to ST78. Among 40 mating tests, lsa (E) was successfully transferred through one conjugation at a frequency of 1.125 × 10–7 transconjugants per donor. The QDA resistance of the transconjugant N7435-R3645 was expressed at a higher level (MIC = 16 mg/L) than that of the parent S. aureus strain (MIC = 0.38 mg/L). Next-generation sequencing (NGS) analysis of the transconjugant N7435-R3645 showed that the complete sequence of the lsa (E)-carrying plasmid pN7435-R3645 had a size of 92,396 bp and a G + C content of 33% (accession no. MT022086). The genetic map of pN7435-R3645 had high nucleotide similarity and shared the main open reading frame (ORF) features with two plasmids: E. faecium pMG1 (AB206333.1) and E. faecium LS170308 (CP025078.1). The rep gene of pN7435-R3645 showed 100% identity with that of pMG1, although it did not belong to the rep 1-19 family but instead a unique rep family. Multiple antibiotic resistance genes, including lsa (E), aadE and lnu (B), erm (B), ant6 -Ia, and lnu (B), were present on the plasmid. In conclusion, an lsa (E)-carrying plasmid that can be transferred by conjugation from E. faecium to S. aureus in vitro was identified. This multidrug resistance (MDR) pMG1-like plasmid may act as a vector in the dissemination of antimicrobial resistance among species. [ABSTRACT FROM AUTHOR]

Objective To investigate the genotypic diversity of Methicillin-resistant Staphylococcus aureus (MRSA) isolated from pigs and retail foods from different geographical areas in China and further to study the routes and rates of transmission of this pathogen from animals to food. Methods Seventy-one MRSA isolates were obtained from pigs and retail foods and then characterized by multi-locus sequencing typing (MLST), spa typing, multiple-locus variable number of tandem repeat analysis (MLVA), pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. Results All isolated MRSA exhibited multi-drug resistance (MDR). Greater diversity was found in food-associated MRSA (7 STs, 8 spa types, and 10 MLVA patterns) compared to pig-associated MRSA (3 STs, 1 spa type, and 6 MLVA patterns). PFGE patterns were more diverse for pig-associated MRSA than those of food-associated isolates (40 vs. 11 pulse types). Among the pig-associated isolates, CC9-ST9-t899-MC2236 was the most prevalent clone (96.4%), and CC9-ST9-t437-MC621 (20.0%) was the predominant clone among the food-associated isolates. The CC9-ST9 isolates showed significantly higher antimicrobial resistance than other clones. Interestingly, CC398-ST398-t034 clone was identified from both pig- and food-associated isolates. Of note, some community- and hospital-associated MRSA strains (t030, t172, t1244, and t4549) were also identified as food-associated isolates. Conclusion CC9-ST9-t899-MC2236-MDR was the most predominant clone in pigs, but significant genetic diversity was observed in food-associated MRSA. Our results demonstrate the great need for improved surveillance of MRSA in livestock and food and effective prevention strategies to limit MDR-MRSA infections in China. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To investigate molecular characterization of streptococcus pyogenes isolates involved in an outbreak of scarlet fever in China in 2011. Methods: Seventy-four Streptococcal pyogenes involved in an outbreak of scarlet fever were isolated from pediatric patients in the areas with high incidence in China from May to August of 2011. Emm genotyping, pulsed-field gel electrophoresis (PFGE), superantigen (SAg) genes and antimicrobial susceptibility profiling were analyzed for these isolates. Results: A total of 4 different emm types were identified. Emm12 was the most prevalent type which contained four predominating PFGE patterns corresponding to four different virulence and superantigen profiles. Emm12 (79.7%) and emm1 (14.9%) accounted for approximately 94% of all the isolates. The speA gene was all negative in emm12 isolates and positive in emm1 isolates. All strains were resistant to erythromycin, and 89.4% of them were resistant to erythromycin, tracycline, and clindamycin simultaneously. Conclusion: Several highly diversified clones with a high macrolide resistance rate comprise a predominant proportion of circulating strains, though no new emm type was found in this outbreak. The data provide a baseline for further surveillance of scarlet fever, which may contribute to the explanation of the outbreak and development of a GAS vaccine in China. [Copyright &y& Elsevier]

Background: Helicobacter pylori ( H. pylori ) persistently colonizes the human gastric mucosa in more than 50% of the global population, leading to various gastroduodenal diseases ranging from chronic gastritis to gastric carcinoma. Cytotoxin-associated gene A (CagA) protein, an important oncoprotein, has highly polymorphic Glu-Pro-Ile-Tyr-Ala segments at the carboxyl terminus, which play crucial roles in pathogenesis. Our previous study revealed a significant association between amino acid deletions at positions 893 and 894 and gastric cancer., Aim: To investigate the impact of amino acid deletions at positions 893 and 894 on CagA function., Methods: We selected a representative HZT strain from a gastric cancer patient with amino acid deletions at positions 893 and 894. The cagA gene was amplified and mutated into cagA -NT and cagA -NE (sequence characteristics of strains from nongastric cancer patients), cloned and inserted into pAdtrack-CMV, and then transfected into AGS cells. The expression of cagA and its mutants was examined using real-time polymerase chain reaction and Western blotting, cell elongation via cell counting, F-actin cytoskeleton visualization using fluorescence staining, and interleukin-8 (IL-8) secretion via enzyme-linked immunosorbent assay., Results: The results revealed that pAdtrack/ cagA induced a more pronounced hummingbird phenotype than pAdtrack/ cagA -NT and pAdtrack/ cagA -NE (40.88 ± 3.10 vs 32.50 ± 3.17, P < 0.001 and 40.88 ± 3.10 vs 32.17 ± 3.00, P < 0.001) at 12 hours after transfection. At 24 hours, pAdtrack/ cagA- NE induced significantly fewer hummingbird phenotypes than pAdtrack/ cagA and pAdtrack/ cagA- NT (46.02 ± 2.12 vs 53.90 ± 2.10, P < 0.001 and 46.02 ± 2.12 vs 51.15 ± 3.74, P < 0.001). The total amount of F-actin caused by pAdtrack/ cagA was significantly lower than that caused by pAdtrack/ cagA- NT and pAdtrack/ cagA- NE (27.54 ± 17.37 vs 41.51 ± 11.90, P < 0.001 and 27.54 ± 17.37 vs 41.39 ± 14.22, P < 0.001) at 12 hours after transfection. Additionally, pAdtrack/ cagA induced higher IL-8 secretion than pAdtrack/ cagA- NT and pAdtrack/ cagA- NE at different times after transfection., Conclusion: Amino acid deletions at positions 893 and 894 enhance CagA pathogenicity, which is crucial for revealing the pathogenic mechanism of CagA and identifying biomarkers of highly pathogenic H. pylori ., Competing Interests: Conflict-of-interest statement: The authors have no conflicts of interest and financial disclosures., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

The aim of this study was to investigate the transferability of acquired linezolid resistance genes and associated mobile genetic elements in an Enterococcus faecalis isolate QZ076, cocarrying optrA , cfr , cfr (D), and poxtA2 genes. MICs were determined by broth microdilution. Whole-genome sequencing (WGS) was performed using the Illumina and Nanopore platforms. The transfer of linezolid resistance genes was investigated by conjugation, using E. faecalis JH2-2 and clinical methicillin-resistant Staphylococcus aureus (MRSA) 109 as recipients. E. faecalis QZ076 harbors four plasmids, designated pQZ076-1 to pQZ076-4, with optrA located in the chromosomal DNA. The gene cfr was located on a novel pseudocompound transposon, designated Tn 7515 , integrated into the 65,961-bp pCF10-like pheromone-responsive conjugative plasmid pQZ076-1. Tn 7515 generated 8-bp direct target duplications (5'-GATACGTA-3'). The genes cfr (D) and poxtA2 were colocated on the 16,397-bp mobilizable broad-host-range Inc18 plasmid pQZ076-4. The cfr -carrying plasmid pQZ076-1 could transfer from E. faecalis QZ076 to E. faecalis JH2-2, along with the cfr (D)- and poxtA2 -cocarrying plasmid pQZ076-4, conferring the corresponding resistant phenotype to the recipient. Moreover, pQZ076-4 could also transfer to MRSA 109. To the best of our knowledge, this study presented the first report of four acquired linezolid resistance genes [ optrA , cfr , cfr (D), and poxtA2 ] being simultaneously present in the same E. faecalis isolate. The location of the cfr gene on a pseudocompound transposon in a pheromone-responsive conjugative plasmid will accelerate its rapid dissemination. In addition, the cfr -carrying pheromone-responsive conjugative plasmid in E. faecalis was also able to mobilize the interspecies transfer of the cfr (D)- and poxtA2 -cocarrying plasmid between enterococci and staphylococci. IMPORTANCE In this study, the simultaneous occurrence of four acquired oxazolidinone resistance genes [ optrA , cfr , cfr (D), and poxtA2 ] was identified in an E. faecalis isolate of chicken origin. The association of the cfr gene with a novel pseudocompound transposon Tn 7515 integrated into a pCF10-like pheromone-responsive conjugative plasmid will accelerate its dissemination. Moreover, the location of the resistance genes cfr (D) and poxtA2 on a mobilizable broad-host-range Inc18 family plasmid represents the basis for their intra- and interspecies dissemination with the aid of a conjugative plasmid and further accelerates the spreading of acquired oxazolidinone resistance genes, such as cfr , cfr (D), and poxtA2 , among Gram-positive pathogens., Competing Interests: The authors declare no conflict of interest.

The impacts of reactive nitrogen (Nr) on the environment significantly increase with population and rapid urbanization. In order to study gaseous Nr and Nr loads to waterbodies at the provincial scale, we established anthropogenic emission inventories in prefecture-level cities in Fujian Province and analyzed the changes in Nr emissions for the years 2000, 2005, and 2010. The total Nr emissions were calculated as 538.4, 587.0, and 620.0 Gg in those three years, respectively. The emissions of Nr increased in nine prefecture-level cities except in Zhangzhou. Among these nine cities, Putian is the fastest growing one. The largest emitters were Zhangzhou and Quanzhou, while Ningde and Xiamen were the smallest ones. Agricultural ecosystems and livestock were the main sources of Nr emissions, both of them accounting for more than 90% of total anthropogenic Nr emissions. Despite rapid growth, energy activities had a minor contribution to total Nr emissions. The per area Nr emissions of each prefecture-level city were highest in Xiamen in the southeast coastal area and lowest in Sanming located in the northwest inland region in 2010. However, the patterns of GDP, population, and emission intensities showed the opposite trends to per area Nr emissions, lowest in Xiamen and highest in Nanping. We further discussed the significance of Nr emissions reductions in different areas based on the analysis of the characteristics of Nr emission sources in prefecture-level cities. The results provide a scientific basis for reducing Nr emissions in Fujian Province and its prefecture-level cities.

Aim: To extend the knowledge of the dynamic interaction between Helicobacter pylori (H. pylori) and host mucosa., Methods: A time-series cDNA microarray was performed in order to detect the temporal gene expression profiles of human gastric epithelial adenocarcinoma cells infected with H. pylori. Six time points were selected to observe the changes in the model. A differential expression profile at each time point was obtained by comparing the microarray signal value with that of 0 h. Real-time polymerase chain reaction was subsequently performed to evaluate the data quality., Results: We found a diversity of gene expression patterns at different time points and identified a group of genes whose expression levels were significantly correlated with several important immune response and tumor related pathways., Conclusion: Early infection may trigger some important pathways and may impact the outcome of the infection., (2010 Baishideng. All rights reserved.)

Objective: To analyze multilocus sequence typing (MLST) of methicillin-resistant Staphylococcus aureus (MRSA) strains in 2000 and 2005, and get a primary knowledge of MLST Characterization of MRSA., Methods: Sequence analysis was conducted on seven allelic genes of 29 methicillin-resistant Staphylococcus aureus strains and 2 methicillin-sensitive Staphylococcus aureus (MSSA) strains and the allelic profiles were gained from internet database., Results: All 12 MRSA strains in 2000 were sequence type (ST) 239 and 10 MRSA strains in 2005 were ST239, while 7 MRSA strains in 2005 were new types, ST5 (41.18%, 7/17). ST6 and ST630 were allelic profiles of 2 MSSA strains. ST239 was the most prevalent allelic profile (75.86%, 22/29), while ST5 was the second prevalent allelic profile (24.14%, 7/29) among all isolates., Conclusion: ST239 and ST5 are the most prevalent MRSA clones in this research. MRSA strains have different allelic profile from MSSA strains. MLST might provide an unambiguous method for assigning MRSA and MSSA isolates to known clones or assigning them as novel clones via the internet. Further studies need to be taken by increasing strains.

Objective: To analyze the monosaccharide composition in the polysaccharides from Rhaponticum uniforum, determine the content of monosaccharide, and provide some references for further research., Method: The monosaccharide composition was determined by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Phenol-sulfuric acid method was used for the determination of the content of polysaccharide., Result: The monosaccharides composition in polysaccharides from R. uniforum are glucose, arabonose and fructose. Their molar ratios are 1 : 1.61 : 2.21. The content of polysaccharide is 95.78%, taking the mixture of monosaccharide compositions as reference substances., Conclusion: HPAEC-PAD can be used to analyze the monosaccharide composition in the polysaccharide with high precision, and the method of phenol-sulfuric acid is simple, convenient and reliable.

Aim: To investigate whether anti-H pylori antibodies have cross-reaction with antigens of erythrocyte membrane., Methods: Blood samples were collected from 14 volunteers (8 positive and 6 negative for H pylori detected by (13)C-urea breath test) of the general population. Erythrocyte membrane proteins of the subjects were examined by Western blot using anti-H pylori serum. The proteins related to the positive bands were identified by mass spectrum analysis., Results: Anti-H pylori antibodies had cross-reaction with the proteins of about 50 kDa of erythrocyte membranes in all samples independent of H pylori infection. One protein in the positive band was identified as Chain S, the crystal structure of the cytoplasmic domain of human erythrocyte Band-3 protein., Conclusion: Anti-H pylori antibodies cross-react with some antigens of human erythrocyte membrane, which may provide a clue for the relationship between H pylori infection and vascular disorders.

Objective: To Investigate the differences of sorbitol fermentation related genes and optimize molecular analysis method for distinguishing an epidemic with nonepidemic strains of Vibrio cholerae., Methods: Sequence analysis on four genes of sugar fermentation stimulation protein, periplasmic maltose-binding protein, periplasmic phosphate-binding protein and periplasmic amino acid-binding protein., Results: In this study, the following data was noticed: for O1 serogroup El Tor biotype V. cholerae, twenty-four epidemic and eight nonepidemic strains were chosen; For O139 serogroup V. cholerae, five epidemic and four nonepidemic strains were chosen. With those genes of sugar fermentation stimulation protein, there were three point mutations. The 106th, 150th, 378th oligonucleotide in epidemic strains were A, A and T, comparing to the nonepidemic strains which were G, G and C. When comparing the protein sequences, epidemic strains had a Threonine at 36th amino acid, whereas nonepidemic strains had an Alanine. The results in O139 serogroup were consistent with those in O1 serogroup El Tor biotype strains. Another two point mutations were found in the genes of periplasmic maltose-binding protein. The 999th, 1003rd oligonucleotides in epidemic strains were A and C, while in nonepidemic which were G and T. For the gene of periplasmic amino acid-binding protein, two point mutations were noticed. The 504th and 690th oligonucleotides in epidemic strains were T and C, but were C and T in nonepidemic. However, no amino acid differences were found in periplasmic maltose-binding protein and periplasmic amino acid-binding protein. For periplasmic amino acid-binding protein gene, there was no difference on oligonucleotide between epidemic and nonepidemic strains., Conclusion: Results suggested that SNPs in these genes might serve as a useful tool to distinguish the epidemic strains from nonepidemic strains. The 36th amino acid mutation of sugar fermentation stimulation protein in epidemic and nonepidemic strains might change the activity of the protein which might be associated with sorbitol fermentation.

Objective: To investigate the antimicrobial activity of Pariet, Tekpron, Nexium, respectively, against Helicobacter pylori (H. pylori) in vitro., Methods: Antimicrobial effects of these medicines were evaluated through detection of MICs for 3 H. pylori strains isolated from different countries., Results: The MIC(99) contents were 2.25 mg/L, 42.5 mg/L and 360 mg/L, respectively, for the three medicines. The strains under testing exhibited the same susceptibility to each medicine. Nexium did not inhibit the bacteria under the concentration of 3.6 - 36 mg/L with more and bigger H. pylori colonies seen when compared with controls., Conclusions: The growth inhibitory activity appeared to be different among the three PPI medicines under investigation, with Rabeprazole the most potential agent of the three. Data suggested that the action of growth inhibition in vitro was resting on the characteristic of the given PPI as well as the supplements of the medicine.

Objective: To identify specific proteins of Helicobacter pylori (H. pylori) that associated with gastric carcinoma., Methods: The whole-cell proteins of H. pylori were separated by two-dimensional electrophoresis (2-DE). The protein maps of four H. pylori strains associated with gastric carcinoma and nine strains that isolated from patients with non-gastric carcinoma were then compared by ImageMaster 2D v3.1. MALDI-TOF mass spectrometry was performed to identify the proteins of interest. The proteins were searched by software mascot and identified by peptide fingerprint map., Results: Three proteins seemed to be associated with gastric carcinoma including acylneuraminate cytidylyltransferase with Mowse score 79 with the sequence coverage of 32%. The other two had no unambiguous protein to match., Conclusion: Acylneuraminate cytidylyltransferase seemed to be a specific H. pylori protein associated with the presence of gastric carcinoma. Other two were novel proteins that might be associated with gastric carcinoma. However, the mechanism needs to be explored.

The prokaryotic expression plasmid pET-30a(+)/sBLyS was constructed and transformed into E. coli BL21 (lambda DE3). The recombinant protein was found to be highly expressed by the plight of soluble part and inclusion body. For the sake of enhancing the proportion of the soluble part, inducement at 16 degrees C for 12 h was ascertained. The expressing product was then purified by Ni2+ affinity chromatography gel. PI of the recombinant human sBLyS(rhsBLyS) is about 7.1-7.3 and it assembles into a homotrimer. The effect of rhsBLyS on B lymphocytes by MTT method told us the B lymphocytes' proliferating capacity dose depended on concentration and also stimulating time of the rhsBLys. With rhsBLyS(2 micrograms/mL) stimulating 3 days, B lymphocytes can proliferate the most.

The full length cDNA of human B lymphocyte stimulator (hBLyS) was amplified by using PCR method from cDNA library of human placenta. After purifying and sequencing, the DNA fragment of functional domain of hBLyS (hsDNA fragment)was amplified by using nested PCR method from the PCR product. The prokaryotic expression plasmid pET-30a( )/ hBLyS was constructed with recombinant DNA techniques after purifying and identifying the hsDNA fragment. Then the plasmid pET-30a( )/ hBLyS was transformed into lambdaDE3 cells and the recombination protein was found to be highly expressed the expression product was purified by affinity chromatography gel, Ni(2 )-IDA, made in our laboratory. The experimental results showed that the sequence of the PCR product was identical with the published hBLyS cDNA sequence and purity of the recombination protein we obtained was high. The activity of the purified recombination protein was very significant in the proliferation test of B lymphocytes.