Safety and efficacy of multi-target TKI combined with nivolumab in check-point inhibitor-refractory patients with advanced NSCLC: a prospective, single-arm, two-stage study.

BACKGROUND: Resistance to immune checkpoint inhibitors (ICIs) represents a major unmet medical need in non-small cell lung cancer (NSCLC) patients. Vascular endothelial growth factor (VEGF) inhibition may reverse a suppressive microenvironment and recover sensitivity to subsequent ICIs. METHODS: This phase Ib/IIa, single-arm study, comprised dose-finding (Part A) and expansion (Part B) cohorts. Patients with ICIs-refractory NSCLC were enrolled to receive anlotinib (a multi-target tyrosine kinase inhibitor) orally (from days 1 to 14 in a 21-day cycle) and nivolumab (360 mg every 3 weeks, intravenously) on a 21-day treatment cycle. The first 21-day treatment cycle was a safety observation period (phase Ib) followed by a phase II expansion cohort. The primary objectives were recommended phase 2 dose (RP2D, part A), safety (part B), and objective response rate (ORR, part B), respectively. RESULTS: Between November 2020 and March 2022, 34 patients were screened, and 21 eligible patients were enrolled (6 patients in Part A). The RP2D of anlotinib is 12 mg/day orally (14 days on and 7 days off) and nivolumab (360 mg every 3 weeks). Adverse events (AEs) of any cause and treatment-related AEs (TRAEs) were reported in all treated patients. Two patients (9.5%) experienced grade 3 TRAE. No grade 4 or higher AEs were observed. Serious AEs were reported in 4 patients. Six patients experienced anlotinib interruption and 4 patients experienced nivolumab interruption due to TRAEs. ORR and disease control rate (DCR) was 19.0% and 76.2%, respectively. Median PFS and OS were 7.4 months (95% CI, 4.3-NE) and 15.2 months (95% CI, 12.1-NE), respectively. CONCLUSION: Our study suggests that anlotinib combined with nivolumab shows manageable safety and promising efficacy signals. Further studies are warranted. TRIAL REGISTRATION: NCT04507906 August 11, 2020.

Dual-Specificity Phosphatase 4 Promotes Malignant Features in Colorectal Cancer Through Cyclic-AMP Response Element Binding Protein/Protein Kinase CAMP-Activated Catalytic Subunit Beta Activation.

INTRODUCTION: Previous studies have demonstrated that Dual-specificity phosphatase 4 (DUSP4) plays an important role in the progression of different tumor types. However, the role and mechanism of DUSP4 in colorectal cancer (CRC) remain unclear. AIMS: We investigate the role and mechanisms of DUSP4 in CRC. METHODS: Immunohistochemistry was used to investigate DUSP4 expression in CRC tissues. Cell proliferation, apoptosis and migration assays were used to validate DUSP4 function in vitro and in vivo. RNA-sequence assay was used to identify the target genes of DUSP4. Human phosphokinase array and inhibitor assays were used to explore the downstream signaling of DUSP4. RESULTS: DUSP4 expression was upregulated in CRC tissues relative to normal colorectal tissues, and DUSP4 expression showed a significant positive correlation with CRC stage. Consistently, we found that DUSP4 was highly expressed in colorectal cancer cells compared to normal cells. DUSP4 knockdown inhibits CRC cell proliferation, migration and promotes apoptosis. Furthermore, the ectopic expression of DUSP4 enhanced CRC cell proliferation, migration and diminished apoptosis in vitro and in vivo. Human phosphokinase array data showed that ectopic expression of DUSP4 promotes CREB activation. RNA-sequencing data showed that PRKACB acts as a downstream target gene of DUSP4/CREB and enhances CREB activation through PKA/cAMP signaling. In addition, xenograft model results demonstrated that DUSP4 promotes colorectal tumor progression via PRKACB/CREB activation in vivo. CONCLUSION: These findings suggest that DUSP4 promotes CRC progression. Therefore, it may be a promising therapeutic target for CRC.

Rationale and design of a phase II trial of dacomitinib in advanced non-small cell lung cancer patients with uncommon epidermal growth factor receptor mutations: a prospective and single arm study (DANCE study).

BACKGROUND: Dacomitinib is a second-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). ARCHER-1050 showed that this agent can improve progression-free survival and overall survival in advanced non-small cell lung cancer patients with sensitive EGFR mutation compared to gefitinib. However, it is unclear whether dacomitinib is effective in patients with sensitizing uncommon EGFR mutations in exon 18-21. The aim of this study is to investigate the safety and efficacy of dacomitinib in these patients. METHODS: This is a single arm, prospective, open label and phase II trial. Sample size will be calculated by a minimax two-stage design method based on the following parameters: α = 0.075, 1-ß = 0.9, P0 = 0.20, P1 = 0.45 and a dropout rate of 10%. A total of 30 eligible patients will be included. Patients will receive continuous oral therapy with dacomitinib (45 mg/day) until disease progression, withdrawal of consent, or unacceptable toxicity, whichever occurs first. The primary endpoint is objective response rate (ORR) per RECIST version 1.1, as assessed by investigators' review. The second endpoint is disease control rate (DCR), PFS, OS, and safety. DISCUSSION: We conduct a single arm, phase II study to investigate the safety and efficacy of dacomitinib in advanced NSCLC patients with sensitizing uncommon EGFR mutations. The results of the DANCE study will provide new data regarding efficacy and safety of these patients. TRIAL REGISTRATION: NCT04504071.

Two homologous Salmonella serogroup C1-specific genes are required for flagellar motility and cell invasion.

BACKGROUND: Salmonella is a major bacterial pathogen associated with a large number of outbreaks of foodborne diseases. Many highly virulent serovars that cause human illness belong to Salmonella serogroup C1, and Salmonella ser. Choleraesuis is a prominent cause of invasive infections in Asia. Comparative genomic analysis in our previous study showed that two homologous genes, SC0368 and SC0595 in Salmonella ser. Choleraesuis were unique to serogroup C1. In this study, two single-deletion mutants (Δ0368 and Δ0595) and one double-deletion mutant (Δ0368Δ0595) were constructed based on the genome. All these mutants and the wild-type strain were subjected to RNA-Seq analysis to reveal functional relationships of the two serogroup C1-specific genes. RESULTS: Data from RNA-Seq indicated that deletion of SC0368 resulted in defects in motility through repression of σ28 in flagellar regulation Class 3. Consistent with RNA-Seq data, results from transmission electron microcopy (TEM) showed that flagella were not present in △0368 and △0368△0595 mutants resulting in both swimming and swarming defects. Interestingly, the growth rates of two non-motile mutants △0368 and △0368△0595 were significantly greater than the wild-type, which may be associated with up-regulation of genes encoding cytochromes, enhancing bacterial proliferation. Moreover, the △0595 mutant was significantly more invasive in Caco-2 cells as shown by bacterial enumeration assays, and the expression of lipopolysaccharide (LPS) core synthesis-related genes (rfaB, rfaI, rfaQ, rfaY, rfaK, rfaZ) was down-regulated only in the △0368△0595 mutant. In addition, this study also speculated that these two genes might be contributing to serotype conversion for Salmonella C1 serogroup based on their apparent roles in biosynthesis of LPS and the flagella. CONCLUSION: A combination of biological and transcriptomic (RNA-Seq) analyses has shown that the SC0368 and SC0595 genes are involved in biosynthesis of flagella and complete LPS, as well as in bacterial growth and virulence. Such information will aid to revealing the role of these specific genes in bacterial physiology and evolution within the serogroup C1.

Marine Bacterial Secondary Metabolites: A Treasure House for Structurally Unique and Effective Antimicrobial Compounds.

The prevalence of antimicrobial resistance reduces the effectiveness of antimicrobial drugs in preventing and treating infectious diseases caused by pathogenic organisms, such as bacteria, fungi, and viruses. Because of the burgeoning growth of microbes with antimicrobial-resistant traits, there is a dire need to identify and develop novel and effective antimicrobial agents to treat infections from antimicrobial-resistant strains. The marine environment is rich in ecological biodiversity and can be regarded as an untapped resource for prospecting novel bioactive compounds. Therefore, exploring the marine environment for antimicrobial agents plays a significant role in drug development and biomedical research. Several earlier scientific investigations have proven that bacterial diversity in the marine environment represents an emerging source of structurally unique and novel antimicrobial agents. There are several reports on marine bacterial secondary metabolites, and many are pharmacologically significant and have enormous promise for developing effective antimicrobial drugs to combat microbial infections in drug-resistant pathogens. In this review, we attempt to summarize published articles from the last twenty-five years (1996-2020) on antimicrobial secondary metabolites from marine bacteria evolved in marine environments, such as marine sediment, water, fauna, and flora.

Molecular Characterization of Cephalosporin-Resistant Salmonella Enteritidis ST11 Isolates Carrying blaCTX-M from Children with Diarrhea.

Salmonella Enteritidis is an important foodborne pathogen with high prevalence of resistance to cephalosporins, imposing a serious threat to public health. Therefore, a total of 162 Salmonella Enteritidis isolates collected from child patients in China from 2007 to 2017 were characterized for their resistance to cephalosporins and investigated the transmission characteristics of cephalosporin resistance gene. We found that 15 (9.26%) isolates were all resistant to cefalotin (minimum inhibitory concentration [MIC] ≥512 µg/mL), ceftazidime (MIC 16-128 µg/mL), ceftriaxone (MIC 64 to ≥512 µg/mL), ceftiofur (MIC 64-256 µg/mL), and cefotaxime (MIC 64 to ≥512 µg/mL) with the possession of cephalosporin resistance genes blaCTX-M-55 (n = 13), blaCTX-M-101 (n = 1), and blaCTX-M-153 (n = 1). Molecular typing further revealed that these 15 isolates belonged to sequence type ST11 and shared close pulsed-field gel electrophoresis patterns, suggesting the possibility of clonal spread in Salmonella Enteritidis interspecies. Furthermore, conjugation experiments were successfully performed in 13 of 15 isolates, and blaCTX-M-55 was present on conjugative plasmids with sizes ranging from 54.7 to 173.4 kb. Compared with recipient Escherichia coli C600, transconjugants conferred elevated MICs for cephalosporins ranging from 2- to 2048-fold. The genetic structure surrounding of blaCTX-M-55 gene in transconjugants were ΔISEcp1-blaCTX-M-55-orf477 (n = 8) and ISEcp1-blaCTX-M-55-orf477 (n = 3), respectively. Taken together, blaCTX-M on the plasmids might contribute to cephalosporin resistance in Salmonella Enteritidis, and conjugative transfer of blaCTX-M-55 might facilitate the spread of cephalosporin resistance in Salmonella Enteritidis. Hence, effective mitigation measurements are needed to reduce the threat caused by cephalosporin-resistant Salmonella Enteritidis to public health.

Prognostic Value of Pre-Autologous Stem Cell Transplantation PET/CT in Diffuse Large B-Cell Lymphoma: The Deauville Score Is Prognostically Superior to ΔSUVmax.

OBJECTIVE: The predictive value of pre-autologous stem cell transplantation (pre-ASCT) positron emission tomography/computed tomography (PET/CT) scans according to different criteria remains elusive in patients with diffuse large B-cell lymphoma (DLBCL). METHODS: A total of 46 DLBCL patients treated with pre-ASCT were enrolled in the present study, and two methods, Deauville score and maximal standardized uptake value reduction (ΔSUVmax), were used to evaluate the PET/CT scans before transplantation. RESULTS: In patients with Deauville 1-3 and ≥4, the 2-year progression-free survival (PFS) rates were 82.8 and 11.8% (p < 0.001), respectively, while the 2-year overall survival (OS) rates were 89.7 and 41.2%, respectively (p < 0.001). When using the ΔSUVmax cut-off of 66% criterion, in patients with a ΔSUVmax of >66 and ≤66%, the 2-year PFS rates were 78.1 and 7.1%, respectively (p < 0.001), while the 2-year OS rates were 87.5 and 35.7%, respectively (p < 0.001). In the univariate analysis, the ΔSUVmax, Deauville score, NCCN-IPI and serum lactate dehydrogenase levels were significantly correlated with the 2-year PFS/OS. Furthermore, the multivariate analysis revealed that the Deauville score was an independent prognostic factor for 2-year PFS. CONCLUSION: The present results indicate that PET/CT scans at pre-ASCT can predict the survival of DLBCL patients, and the Deauville score is better than ΔSUVmax in prognostic prediction.

Prevalence and Characterization of Antimicrobial Resistance in Salmonella enterica Isolates from Retail Foods in Shanghai, China.

This study characterized the prevalence and antimicrobial resistance characteristics of foodborne Salmonella isolates from March 2016 to February 2017 in Shanghai, China. A total of 147 (14.2%) nonduplicate foodborne Salmonella isolates were obtained from 1035 food samples. The Salmonella isolates were most frequently identified in fresh meat samples (28.0%), followed by ready-to-eat foods (9.0%), frozen convenience foods (7.1%), and fresh produce (4.5%). The top 3 serovars were Salmonella Enteritidis (46.3%; 68/147), Salmonella Typhimurium (32.7%; 48/147), and Salmonella Derby (6.8%; 10/147). The majority of isolates were resistant to sulfisoxazole (93.9%; 138/147) and trimethoprim/sulfamethoxazole (61.2%; 90/147). Interestingly, frozen convenience food isolates exhibited an extremely high multidrug resistance rate (86.7%; resistant to ≥3 classes of antimicrobials). Among 81 quinolone-resistant isolates, aac(6')-Ib-cr (100%), oqxAB (84.0%), qnrS1 (23.5%), D87Y (49.4%), and D87N (33.3%) mutations in GyrA, and T57S in ParC (12.3%) were observed. The ß-lactamase genes blaTEM-1 (100%) were present in 63 ampicillin-resistant isolates. Polymerase chain reaction-based plasmid replicon typing revealed that 147 isolates represented 6 plasmid incompatibility groups (IncFIIs, IncHI2, IncI1, IncP, IncFIC, and IncA/C), among which, IncFIIs (59.2%) and IncHI2 (26.5%) were predominant. The genetic relationship of isolates was elucidated using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). MLST results indicated that ST34 and ST11 were predominate types in Salmonella Typhimurium (56.3%; 27/48) and Salmonella Enteritidis (95.6%; 65/68), respectively. Importantly, 96.3% (26/27) of ST34 Salmonella Typhimurium isolates possessed the ACSSuT resistance pattern (ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline). PFGE analysis of ST34 isolates showed clonal dissemination across all four types of retail foods. Our findings highlight the high prevalence of antimicrobial-resistant Salmonella isolates in retail foods in Shanghai, especially the clonal expansion of ST34 isolates with MDR-ACSSuT resistance, which might pose a public health threat.

Erlotinib as Neoadjuvant Therapy in Stage IIIA (N2) EGFR Mutation-Positive Non-Small Cell Lung Cancer: A Prospective, Single-Arm, Phase II Study.

LESSONS LEARNED: The findings of this prospective, single-arm, phase II study showed that neoadjuvant erlotinib was well tolerated and might improve the radical resection rate in patients with stage IIIA-N2 epidermal growth factor receptor mutation-positive non-small cell lung cancer (NSCLC).Erlotinib shows promise as a neoadjuvant therapy option in this patient population.Next-generation sequencing may be useful for predicting outcomes with preoperative tyrosine kinase inhibitors (TKIs) in patients with NSCLC.Large-scale randomized controlled trials investigating the role of TKIs in perioperative therapy, combining neoadjuvant and adjuvant treatments to enhance personalized therapy for patients in this precision medicine era, are warranted. BACKGROUND: Information on epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) as neoadjuvant therapy in non-small cell lung cancer (NSCLC) is scarce. We evaluated whether neoadjuvant erlotinib improves operability and survival in patients with stage IIIA-N2 EGFR mutation-positive NSCLC. METHODS: We conducted a prospective, single-arm, phase II study. Patients received erlotinib 150 mg per day for 56 days in the neoadjuvant period. The primary endpoint was the radical resection rate. RESULTS: Nineteen patients were included in the final analysis. After erlotinib treatment, 14 patients underwent surgery. The radical resection rate was 68.4% (13/19) with a 21.1% (4/19) rate of pathological downstaging. The objective response rate was 42.1%; 89.5% (17/19) of patients achieved disease control, with a 10.3-month median disease-free survival among patients who underwent surgery. Among all 19 patients who received neoadjuvant therapy, median progression-free survival (PFS) and overall survival were 11.2 and 51.6 months, respectively. Adverse events (AEs) occurred in 36.8% (7/19) of patients, with the most common AE being rash (26.3%); 15.8% experienced grade 3/4 AEs. Quality of life (QoL) improvements were observed after treatment with erlotinib for almost all QoL assessments. Effects of TP53 mutation on prognosis were evaluated in eight patients with adequate tissue samples. Next-generation sequencing revealed that most patients had a TP53 gene mutation (7/8) in addition to an EGFR mutation. No TP53 mutation, or very low abundance, was associated with longer PFS (36 and 38 months, respectively), whereas high abundance was associated with short PFS (8 months). CONCLUSION: Neoadjuvant erlotinib was well tolerated and may improve the radical resection rate in this patient population. Next-generation sequencing may predict outcomes with preoperative TKIs.

Ethanol Adaptation Strategies in Salmonella enterica Serovar Enteritidis Revealed by Global Proteomic and Mutagenic Analyses.

Salmonella enterica subsp. enterica serovar Enteritidis is able to adapt to sublethal concentrations of ethanol, which subsequently induce tolerance of this pathogen to normally lethal ethanol challenges. This work aims to elucidate the underlying ethanol adaptation mechanisms of S Enteritidis by proteomic and mutagenic analyses. The global proteomic response of S Enteritidis to ethanol adaptation (5% ethanol for 1 h) was determined by isobaric tags for relative and absolute quantification (iTRAQ), and it was found that a total of 138 proteins were differentially expressed in ethanol-adapted cells compared to nonadapted cells. A total of 56 upregulated proteins were principally associated with purine metabolism and as transporters for glycine betaine, phosphate, d-alanine, thiamine, and heme, whereas 82 downregulated proteins were mainly involved in enterobactin biosynthesis and uptake, the ribosome, flagellar assembly, and virulence. Moreover, mutagenic analysis further revealed the functions of two highly upregulated proteins belonging to purine metabolism (HiuH, 5-hydroxyisourate hydrolase) and glycine betaine transport (ProX, glycine betaine-binding periplasmic protein) pathways. Deletion of either hiuH or proX resulted in the development of a stronger ethanol tolerance response, suggesting negative regulatory roles in ethanol adaptation. Collectively, this work suggests that S Enteritidis employs multiple strategies to coordinate ethanol adaptation.IMPORTANCE Stress adaptation in foodborne pathogens has been recognized as a food safety concern since it may compromise currently employed microbial intervention strategies. While adaptation to sublethal levels of ethanol is able to induce ethanol tolerance in foodborne pathogens, the molecular mechanism underlying this phenomenon is poorly characterized. Hence, global proteomic analysis and mutagenic analysis were conducted in the current work to understand the strategies employed by Salmonella enterica subsp. enterica serovar Enteritidis to respond to ethanol adaptation. It was revealed that coordinated regulation of multiple pathways involving metabolism, ABC transporters, regulators, enterobactin biosynthesis and uptake, the ribosome, flagellar assembly, and virulence was responsible for the development of ethanol adaptation response in this pathogen. Such knowledge will undoubtedly contribute to the development and implementation of more-effective food safety interventions.

Identification and characterization of two novel superantigens among Staphylococcus aureus complex.

Staphylococcal enterotoxins (SEs), also known as superantigens, play a very important role in infections and food poisoning caused by Staphylococcus aureus. Recently, S. argenteus and S. schweitzeri were recognized as novel species closely related to S. aureus. In this study of these three species, it was found that two putative SE genes were located upstream of some vSaß pathogenicity islands and the deduced amino acid sequences showed < 65.3% identity with those of known SEs. The related proteins, designated staphylococcal enterotoxin-like toxin 26 (SEl26) and 27 (SEl27), were identified and characterized among the three species. The mRNAs encoding SEl26 and SEl27 were expressed during all the growth phases. Recombinant SEl26 and SEl27 exhibited superantigenic activity in human peripheral blood mononuclear cells and mouse splenocytes by examining cell proliferation and cytokine production. Interestingly, these two genes were present universally in S. argenteus sequence type 2250 with clinical importance. Meanwhile, SEl27 variants from different species showed differential sensitivity to human peripheral blood mononuclear cells, which corresponded to the primary bacterial species hosts. It was demonstrated from these results that SEl26 and SEl27 were characterized to be two novel SE toxins and some SEs evolved along with the bacteria when the organisms adapted the hosts' immune systems.

Influence of ethanol adaptation on Salmonella enterica serovar Enteritidis survival in acidic environments and expression of acid tolerance-related genes.

Cross-protection to environmental stresses by ethanol adaptation in Salmonella poses a great threat to food safety because it can undermine food processing interventions. The ability of Salmonella enterica serovar Enteritidis (S. Enteritidis) to develop acid resistance following ethanol adaptation (5% ethanol for 1 h) was evaluated in this study. Ethanol-adapted S. Enteritidis mounted cross-tolerance to malic acid (a two-fold increase in minimum bactericidal concentration), but not to acetic, ascorbic, lactic, citric and hydrochloric acids. The population of S. Enteritidis in orange juice (pH 3.77) over a 48-h period was not significantly (p > 0.05) influenced by ethanol adaptation. However, an increased survival by 0.09-1.02 log CFU/ml was noted with ethanol-adapted cells of S. Enteritidis compared to non-adapted cells in apple juice (pH 3.57) stored at 25 °C (p < 0.05), but not at 4 °C. RT-qPCR revealed upregulation of two acid tolerance-related genes, rpoS (encoding σS) and SEN1564A (encoding an acid shock protein), following ethanol adaptation. The relative expression level of the acid resistance gene hdeB did not change. The resistance phenotypes and transcriptional profiles of S. Enteritidis suggest some involvement of rpoS and SEN1564A in the ethanol-induced acid tolerance mechanism.

Antimicrobial Resistance and Molecular Characterization of Salmonella enterica Serovar Enteritidis from Retail Chicken Products in Shanghai, China.

Salmonella enterica serovar Enteritidis is the leading global cause of salmonellosis. A total of 146 Salmonella Enteritidis isolates obtained from retail chicken products in Shanghai, China were characterized for their antimicrobial susceptibilities, virulence and antibiotic resistance gene profiles, and molecular subtypes using pulsed-field gel electrophoresis (PFGE). Approximately 42% (61/146) of the isolates were susceptible to all 13 antimicrobials tested. More than half of the isolates (50.70%) were resistant to ampicillin, 49.32% to sulfisoxazole, 17.12% to tetracycline, and 15.75% to doxycycline. Thirty (20.55%) isolates were resistant to three or more antimicrobials. The avrA, mgtC, and sopE virulence genes were identified in all isolates, while 97.2% and 92.4% were positive for bcfC and spvC genes, respectively. Genes associated with resistance to streptomycin (aadA), ß-lactams (blaTEM, blaCMY, blaSHV, and blaCTX), tetracycline (tetA and tetB), and sulfonamides (sulI, sulII, and sulIII) were detected among corresponding resistant isolates. A total of 41 PFGE patterns were identified from 77 antimicrobial resistance (AMR) isolates and were primarily grouped into seven clusters (A-G), each with 90% similarity. The majority of Salmonella Enteritidis isolates (63.63%, 49/77) shared the same PFGE cluster, indicating potential cross contamination during processing and cutting or working during retailing and marketing. A significantly (p < 0.05) lower percentage (<25%) of isolates belonging to clusters D and E were resistant to sulfisoxazole compared with those belonging to clusters A, B, C, F, and G (>80%), indicating that sulfisoxazole resistance might be associated with genetic content (PFGE profiles) of Salmonella Enteritidis. This study provides important and updated information about the baseline antimicrobial-resistant data for food safety risk assessment of Salmonella Enteritidis from retailed chicken in Shanghai, which is the first step for the development and implementation of China's AMR National Action Plan, and can be helpful for future surveillance activities to ensure the safety of the chicken supply.

Preliminary comparative genomics revealed pathogenic potential and international spread of Staphylococcus argenteus.

BACKGROUND: Staphylococcus argenteus and S. schweitzeri, were recently proposed as novel species within S. aureus complex (SAC). S. argenteus has been reported in many countries and can threaten human health. S. schweitzeri has not been associated with human infections, but has been isolated from non-human primates. Questions regarding the evolution of pathogenicity of these two species will remain elusive until an exploratory evolutionary framework is established. RESULTS: We present genomic comparison analysis among members of SAC based on a pan-genome definition, which included 15 S. argenteus genomes (five newly sequenced), six S. schweitzeri genomes and 30 divergent S. aureus genomes. The three species had divergent core genomes and rare interspecific recombination was observed among the core genes. However, some subtypes of staphylococcal cassette chromosome mec (SCCmec) elements and prophages were present in different species. Of 111 tested virulence genes of S. aureus, 85 and 86 homologous genes were found in S. argenteus and S. schweitzeri, respectively. There was no difference in virulence gene content among the three species, but the sequence of most core virulence genes was divergent. Analysis of the agr locus and the genes in the capsular polysaccharides biosynthetic operon revealed that they both diverged before the speciation of SAC members. Furthermore, the widespread geographic distribution of S. argenteus, sequence type 2250, showed ambiguous biogeographical structure among geographically isolated populations, demonstrating an international spread of this pathogen. CONCLUSIONS: S. argenteus has spread among several countries, and invasive infections and persistent carriage may be not limited to currently reported regions. S. argenteus probably had undergone a recent host adaption and can cause human infections with a similar pathogenic potential.

Combination of chemotherapy and gefitinib as first-line treatment for patients with advanced lung adenocarcinoma and sensitive EGFR mutations: A randomized controlled trial.

To explore the optimal treatment strategy for patients who harbor sensitive EGFR mutations, a head-to-head study was performed to compare chemotherapy and gefitinib in combination or with either agent alone as first-line therapy, in terms of efficacy and safety. A total of 121 untreated patients with advanced lung adenocarcinoma who harbored sensitive EGFR mutations were randomly assigned to receive gefitinib combined with pemetrexed and carboplatin, pemetrexed plus carboplatin or gefitinib alone. The progression-free survival (PFS) of patients in the combination group (17.5 months, 95% CI, 15.3-19.7) was longer than that of patients in the chemotherapy group (5.7 months, 95% CI, 5.2-6.3) or gefitinib (11.9 months, 95% CI, 9.1-14.6) group. The (hazard ratios) HRs of PFS for the combination group vs. chemotherapy and gefitinib groups were 0.16 (95% CI, 0.09-0.29, p < 0.001) and 0.48 (95% CI, 0.29-0.78, p = 0.003), respectively. The overall response rate (ORR) in the combination therapy group, chemotherapy group and the gefitinib group was 82.5%, 32.5% and 65.9%, respectively. The combinational strategy resulted in longer overall survival (OS) than chemotherapy (HR = 0.46, p = 0.016) or gefitinib (HR = 0.36, p = 0.001) alone. Our finding suggested that treatment with pemetrexed plus carboplatin combined with gefitinib could provide better survival benefits for patients with lung adenocarcinoma harboring sensitive EGFR mutations.

Molecular Typing and Virulence Gene Profiles of Enterotoxin Gene Cluster (egc)-Positive Staphylococcus aureus Isolates Obtained from Various Food and Clinical Specimens.

The enterotoxin gene cluster (egc) has been proposed to contribute to the Staphylococcus aureus colonization, which highlights the need to evaluate genetic diversity and virulence gene profiles of the egc-positive population. Here, a total of 43 egc-positive isolates (16.2%) were identified from 266 S. aureus isolates that were obtained from various food and clinical specimens in Shanghai. Seven different egc profiles were found based on the polymerase chain reaction (PCR) result for egc genes. Then, these 43 egc-positive isolates were further typed by multilocus sequence typing, pulsed-field gel electrophoresis (PFGE), multiple-locus variable-number tandem-repeat analysis (MLVA), and accessory gene regulatory (agr) typing. It showed that the 43 egc-positive isolates displayed 17 sequence types, 28 PFGE patterns, 29 MLVA types, and 4 agr types, respectively. Among them, the dominant clonal lineage was CC5-agr II (48.84%). Thirty toxin and 20 adhesion-associated genes were detected by PCR in egc-positive isolates. Notably, invasive toxin genes showed a high prevalence, such as 76.7% for Panton-Valentine leukocidin encoding genes, 27.9% for sec, and 23.3% for tsst-1. Most of the examined adhesion-associated genes were found to be conserved (76.7-100%), whereas the fnbB gene was only found in 8 (18.6%) isolates. In addition, 33 toxin gene profiles and 13 adhesion gene profiles were identified, respectively. Our results imply that isolates belonging to the same clonal lineage harbored similar adhesion gene profiles but diverse toxin gene profiles. Overall, the high prevalence of invasive virulence genes increases the potential risk of egc-positive isolates in S. aureus infection.

Molecular methods for serovar determination of Salmonella.

Salmonella is a diverse foodborne pathogen, which has more than 2600 recognized serovars. Classification of Salmonella isolates into serovars is essential for surveillance and epidemiological investigations; however, determination of Salmonella serovars, by traditional serotyping, has some important limitations (e.g. labor intensive, time consuming). To overcome these limitations, multiple methods have been investigated to develop molecular serotyping schemes. Currently, molecular methods to predict Salmonella serovars include (i) molecular subtyping methods (e.g. PFGE, MLST), (ii) classification using serovar-specific genomic markers and (iii) direct methods, which identify genes encoding antigens or biosynthesis of antigens used for serotyping. Here, we reviewed reported methodologies for Salmonella molecular serotyping and determined the "serovar-prediction accuracy", as the percentage of isolates for which the serovar was correctly classified by a given method. Serovar-prediction accuracy ranged from 0 to 100%, 51 to 100% and 33 to 100% for molecular subtyping, serovar-specific genomic markers and direct methods, respectively. Major limitations of available schemes are errors in predicting closely related serovars (e.g. Typhimurium and 4,5,12:i:-), and polyphyletic serovars (e.g. Newport, Saintpaul). The high diversity of Salmonella serovars represents a considerable challenge for molecular serotyping approaches. With the recent improvement in sequencing technologies, full genome sequencing could be developed into a promising molecular approach to serotype Salmonella.

Isolation and Analysis of the Cppsy Gene and Promoter from Chlorella protothecoides CS-41.

Phytoene synthase (PSY) catalyzes the condensation of two molecules of geranylgeranyl pyrophosphate to form phytoene, the first colorless carotene in the carotenoid biosynthesis pathway. So it is regarded as the crucial enzyme for carotenoid production, and has unsurprisingly been involved in genetic engineering studies of carotenoid production. In this study, the psy gene from Chlorella protothecoides CS-41, designated Cppsy, was cloned using rapid amplification of cDNA ends. The full-length DNA was 2488 bp, and the corresponding cDNA was 1143 bp, which encoded 380 amino acids. Computational analysis suggested that this protein belongs to the Isoprenoid_Biosyn_C1 superfamily. It contained the consensus sequence, including three predicted substrate-Mg(2+) binding sites. The Cppsy gene promoter was also cloned and characterized. Analysis revealed several candidate motifs for the promoter, which exhibited light- and methyl jasmonate (MeJA)-responsive characteristics, as well as some typical domains universally discovered in promoter sequences, such as the TATA-box and CAAT-box. Light- and MeJA treatment showed that the Cppsy expression level was significantly enhanced by light and MeJA. These results provide a basis for genetically modifying the carotenoid biosynthesis pathway in C. protothecoides.

Phenotypic and Genotypic Characterization of Salmonella enterica Serovar Enteritidis Isolates Associated with a Mousse Cake-Related Outbreak of Gastroenteritis in Ningbo, China.

Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) is a major pathogen responsible for causing the largest number of sporadic cases and outbreaks of human salmonellosis worldwide. In this study, an outbreak of Salmonella Enteritidis involving 112 cases in Ningbo, China was investigated with a combination of genotypic subtyping methods and phenotypic analysis. The pulsed-field gel electrophoresis and multilocus variable-number tandem-repeat analysis profiles showed that most of the outbreak clinical isolates (22/23) were indistinguishable from each other and were identical to the isolates obtained from implicated mousse cakes, demonstrating that this outbreak of gastroenteritis was caused by Salmonella Enteritidis-contaminated mousse cakes. Moreover, all isolates, irrespective of source, had an identical antibiotic susceptibility pattern. Five virulence-associated genes in Salmonella pathogenicity islands and the plasmid-associated virulence genes spvB/C were present in both the food and clinical isolates. Importantly, all of these isolates can survive well under low-temperature treatment, indicating that manufacturers of foodstuffs with raw ingredients (not subjected to thermal processing) should use an effective approach to prevent or eliminate the microbial hazards to public health.

Notch 3 protein, not its gene polymorphism, is associated with the chemotherapy response and prognosis of advanced NSCLC patients.

AIM: To study the relation of NOTCH3 and its gene polymorphisms with the chemotherapy response and the prognosis of patients with Non-small cell lung cancer (NSCLC). METHODS: A total of 594 patients with advanced stage of NSCLC (IIIA, IIIB and IV) NSCLC were enrolled. All patients received Platinum-based chemotherapy. The NOTCH3 expression in tumors and its gene polymorphisms were determined. In vitro, several NSCLC cell lines received the NOTCH3 over-expression vector and small interfering RNA (siRNA) to study the role of NOTCH3 in regulation the cellular biological behaviors. RESULTS: The genotype and the allele frequencies of NOTCH3 gene polymorphisms at 605C>T and 1735T>C were not significantly different between good responders and poor responders to chemotherapy. However, high NOTCH3 expression in tumor represented a significantly higher possibility of being resistant to chemotherapy. Also, patients with high NOTCH3 expression had a poorer prognosis than those with low NOTCH3 expression. In vitro studies showed that NOTCH3 inhibition dramatically suppressed the proliferation, migration, invasiveness abilities and prompted apoptosis in NSCLC cells. CONCLUSION: NOTCH3 regulates the cellular behavior, including, proliferation, marker to predict the chemotherapy response and prognosis of advanced NSCLC. marker to predict the chemotherapy response and prognosis of advanced NSCLC.