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Single-minded homolog 2 (SIM2) has been identified as a potential contributor to the development of solid tumors. Despite this, there is a lack of comprehensive research regarding its biological role and underlying mechanism within pancreatic cancer (PC), as well as its prognostic impact. This study systematically evaluated the expression level and clinical significance of SIM2 in patients with PC using various databases, including The Cancer Genome Atlas, KM Plotter, and gene expression profiling interactive analysis. To investigate the relationship between SIM2 expression and immune cell infiltration, we conducted ESTIMATE and single-sample gene set enrichment analysis (ssGSEA) analyses. Single-minded homolog 2 was up-regulated in patients with PC. Pancreatic cancer patients with higher SIM2 expression had poorer overall survival rates. Gene set enrichment analysis results suggested that SIM2 may have a significant impact on the progression of PC and the regulation of immune responses. According to the ssGSEA algorithm, SIM2 has a negative correlation with the levels of infiltrating TFH, mast cells, and pDC. Our study demonstrated that SIM2 serves as a biomarker, and is associated with both prognosis and immune infiltration in PC. This provides a solid foundation for future investigations into the precise role of SIM2 in the carcinogenesis and progression of PC.

ABSTRACT Campylobacter jejuni is a bacterium that is commonly present in the intestinal tracts of animals. It is also a major foodborne pathogen that causes gastroenteritis in humans. The most predominant and clinically important multidrug efflux system in C. jejuni is the CmeABC (Campylobacter multidrug efflux) pump, a tripartite system that includes an inner membrane transporter (CmeB), a periplasmic fusion protein (CmeA), and an outer membrane channel protein (CmeC). This efflux protein machinery mediates resistance to a number of structurally diverse antimicrobial agents. A recently identified CmeB variant, termed resistance enhancing CmeB (RE-CmeB), can increase its multidrug efflux pump activity, likely by influencing antimicrobial recognition and extrusion. Here, we report structures of RE-CmeB in its apo form as well as in the presence of four different drugs by using single-particle cryo-electron microscopy (cryo-EM). Coupled with mutagenesis and functional studies, this structural information allows us to identify critical amino acids that are important for drug resistance. We also report that RE-CmeB utilizes a somewhat unique subset of residues to bind different drugs, thereby optimizing its ability to accommodate different compounds with distinct scaffolds. These findings provide insights into the structure-function relationship of this newly emerged antibiotic efflux transporter variant in Campylobacter. IMPORTANCE Campylobacter jejuni has emerged as one of the most problematic and highly antibiotic-resistant pathogens, worldwide. The Centers for Disease Control and Prevention have designated antibiotic-resistant C. jejuni as a serious antibiotic resistance threat in the United States. We recently identified a C. jejuni resistance enhancing CmeB (RE-CmeB) variant that can increase its multidrug efflux pump activity and confers an exceedingly high-level of resistance to fluoroquinolones. Here, we report the cryo-EM structures of this prevalent and clinically important C. jejuni RE-CmeB multidrug efflux pump in both the absence and presence of four antibiotics. These structures allow us to understand the action mechanism for multidrug recognition in this pump. Our studies will ultimately inform an era in structure-guided drug design to combat multidrug resistance in these Gram-negative pathogens.

Background: ACSMs play critical roles in lipid metabolism; however, their immunological function within the tumor microenvironment (TME) remains unclear, especially that of ACSM6. In this study, we investigate the latent effect of ACSM6 on bladder cancer (BLCA).Methods: Several real-world cohorts, including the Xiangya (in-house), The Cancer Genome Atlas (TCGA-BLCA), and IMvigor210 cohorts, with TCGA-BLCA cohort serving as the discovery cohort were compared. We investigated the potential immunological effects of ACSM6 in regulating the BLCA tumor microenvironment by analyzing its correlation with immunomodulators, anti-cancer immune cycles, immune checkpoints, tumor-infiltrating immune cells, and the T-cell inflamed score (TIS). Additionally, we assessed the precision of ACSM6 in predicting BLCA molecular subtypes and responses to several treatments using ROC analysis. To ensure the robustness of our findings, all results were confirmed in two independent external cohorts: the IMvigor210 and Xiangya cohorts.Results: ACSM6 expression was markedly upregulated in BLCA. Our analysis suggests that ACSM6 might have significant impact to promote the formation of a non-inflamed tumor microenvironment because of its negative correlation with immunomodulators, anticancer immune cycles, immune checkpoints, tumor-infiltrating immune cells, and the T-cell inflamed score (TIS). Additionally, high ACSM6 expression levels in BLCA may predict the luminal subtype, which is typically associated with resistance to chemotherapy, neoadjuvant chemotherapy, and radiotherapy. These findings were consistent across both the IMvigor210 and Xiangya cohorts.Conclusion: ACSM6 has the potential to serve as a valuable predictor of the tumor microenvironment phenotypes and treatment outcomes in BLCA, thereby contributing to more precise treatment.

AIMS: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus belonging to the Coronaviridae family that causes coronavirus disease (COVID-19). This disease rapidly reached pandemic status, presenting a serious threat to global health. However, the detailed molecular mechanism contributing to COVID-19 has not yet been elucidated. METHODS: The expression profiles, including the mRNA levels, of samples from patients infected with SARS-CoV-2 along with clinical data were obtained from the GSE152075 dataset in the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was used to identify co-expression modules, which were then implemented to evaluate the relationships between fundamental modules and clinical traits. The differentially expressed genes (DEGs), gene ontology (GO) functional enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were evaluated using R software packages. RESULTS: A total of 377 SARS-CoV-2-infected samples and 54 normal samples with available clinical and genetic data were obtained from the GEO database. There were 1444 DEGs identified between the sample types, which were used to screen out 11 co-expression modules in the WGCNA. Six co-expression modules were significantly associated with three clinical traits (SARS-CoV-2 positivity, age, and sex). Among the DEGs in two modules significantly correlated with SARS-CoV-2 positivity, enrichment was observed in the biological process of viral infection strategies (viral translation) in the GO analysis. The KEGG signalling pathway analysis demonstrated that the DEGs in the two modules were commonly enriched in oxidative phosphorylation, ribosome, and thermogenesis pathways. Moreover, a five-core gene set (RPL35A, RPL7A, RPS15, RPS20, and RPL17) with top connectivity with other genes was identified in the SARS-CoV-2 infection modules, suggesting that these genes may be indispensable in viral transcription after infection. CONCLUSION: The identified core genes and signalling pathways associated with SARS-CoV-2 infection can significantly supplement the current understanding of COVID-19. The five core genes encoding ribosomal proteins may be indispensable in viral protein biosynthesis after SARS-CoV-2 infection and serve as therapeutic targets for COVID-19 treatment. These findings can be used as a basis for creating a hypothetical model for future experimental studies regarding associations of SARS-CoV-2 infection with ribosomal protein function.

Stephanie Peters, Ben Pascoe, et al. use whole-genome sequencing and phenotypic analysis of clinical strains from patients to identify potential genetic factors involved in irritable bowel syndrome resulting from Campylobacter jejuni infection. Their data suggest that genes involved in the bacterial stress response and biosynthetic pathways may contribute toward irritable bowel syndrome, providing further insight into links between Campylobacter genotypes and risk of disease.

BackgroundThe prognostic nutrition index (PNI), which has been evaluated in various kinds of cancers, offered a simple yet effective approach to predict the prognosis. The aim of this meta-analysis is to reveal the correlation between preoperative PNI and the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) who underwent curative resection.MethodsWe searched the PubMed, Embase, Web of Science and Cochrane Library databases, and extracted the hazard ratio (HR) with 95% confidential interval (CI) from eligible studies. The pooled HR with 95% CI was applied to evaluate the association between PNI and overall survival (OS), recurrence-free survival (RFS).ResultsA total of fourteen studies with 3,385 patients were included for meta-analysis. The results (the pooled HR: 1.664, 95% CI: 1.424–1.994, I² = 42.6%, p value = 0.046) indicated that low preoperative PNI was closely related to poor OS. In addition, the results suggested that PNI was negatively correlated with RFS (the pooled HR: 1.369, 95%CI: 1.080–1.734). The robustness of these pooled results was verified by our subgroup analysis and sensitivity analysis. Moreover, different cutoff values among studies are responsible for the heterogeneity of pooled HR of OS through meta-regression analysis (p value = 0.042). Funnel plots, Begg's test (p value = 0.228) and Egger’s test (p value = 0.702) indicated no significant publication bias in OS.ConclusionPreoperative PNI might be a promising marker to predict the prognosis of PDAC patients who underwent curative resection.

BackgroundBladder carcinoma (BLCA) is a heterogeneous disease that makes it difficult to achieve proper individual treatment and predict prognosis. This study aimed to develop a risk score from a new perspective of pyroptosis and guide accurate treatment and prognosis prediction for BLCA.MethodsThe TCGA-BLCA cohort data were downloaded from The Cancer Genome Atlas database. Two external validation cohorts were collected from the Gene Expression Omnibus. Another independent validation cohort (the Xiangya cohort) was recruited from our hospital. The least absolute shrinkage and selector operation (LASSO) algorithm and Cox regression models were used to establish the pyroptosis risk score. Thereafter, we correlated the pyroptosis risk score with prognosis, tumor microenvironment (TME) immune hallmarks, and multiple treatments, including anticancer immunotherapy, chemotherapy, radiotherapy, and targeted therapy.ResultsThe pyroptosis risk score was an independent prognostic predictor of BLCA. We found that the activities of multiple steps of the anticancer immune response cycle, such as the release of cancer cell antigens, CD8 T cell recruitment, and NK cell recruitment, were significantly higher in the high-risk score group than in the low-risk score group. In addition, the infiltration levels of the corresponding tumor-infiltrating immune cells (TIICs), such as CD8 T cells and NK cells, were positively correlated with the pyroptosis risk score. Thus, BLCA with a high-risk score may be associated with inflamed phenotypes. Simultaneously, the expression of multiple immune checkpoints (such as PD-L1, CTLA-4, and PD-1) and enrichment scores of gene signatures positively correlated with immunotherapy response were positively correlated with the pyroptosis risk score. Therefore, patients with a high pyroptosis risk score may be more sensitive to immunotherapy. In addition, patients with high pyroptosis risk scores may be more sensitive to chemotherapeutic drugs, such as cisplatin, docetaxel, and paclitaxel. In addition, the pyroptosis risk score accurately predicted the molecular subtypes of BLCA, which were cross-validated in several independent systems.ConclusionsThis study developed and validated a robust pyroptosis risk score that can predict the clinical outcomes and TME immune phenotypes of BLCA. In summary, the pyroptosis risk score helps drive precision therapy in patients with BLCA.

BackgroundPancreatic cancer mortality is growing every year, and radical resection is the most essential therapy strategy. It is critical to evaluate the long-term prognosis of individuals receiving radical surgery. CA19-9 is a biomarker for patient recurrence and survival, however obstructive jaundice has a significant impact on this index. Researchers have attempted to modify the index using various modification methods, but the results have been unsatisfactory. In this study, we adjusted CA19-9 values based on clinical stage and bilirubin and found that it provided better prediction than CA19-9 alone in assessing patients.MethodsWe analyzed over 5 years follow-up records of patients who underwent radical pancreatic cancer surgery between August 2009 and May 2017 in a single center. We investigated the association of risk factors with overall survival (OS) as well as disease-free survival (DFS) after surgery. Threshold values for high-risk features associated with poor prognosis in resectable pancreatic cancer were determined. The hazard ratios of the indicators were eventually examined under the stratification of patients’ clinical stages.ResultsA total of 202 patients were involved in the study. The optimum cut-off values for CA19-9 and CA19-9/TB for predicting overall survival were 219.4 (p = 0.0075) and 18.8 (p = 0.0353), respectively. CA19-9>219.4 increased the risk of patient mortality by 1.70 times (95% CI 1.217-2.377, p = 0.002), and tumor poor differentiation raised the risk by 1.66 times (95% CI 1.083-2.553, P = 0.02). Based on clinical stage stratification, we found discrepancies in the predictive efficacy of CA19-9 and CA19-9/TB. CA19-9 was a better predictor in clinical stage 1 (HR = 2.056[CI 95%1.169-3.616], P = 0.012), whereas CA19-9/TB indications were better in stages 2 (HR = 1.650[CI 95%1.023-2.662], P = 0.040) and 3 (HR = 3.989[CI95%1.145-13.896], P = 0.030).ConclusionsCA19-9, CEA, and tumor differentiation are predictors for patients with resectable PDAC. CA19-9 values can be adjusted based on clinical stage and bilirubin levels to better predict overall survival in patients with resectable PDAC. CA19-9>219.4 predicted poor survival in individuals in clinical stage 1, whereas CA19-9/TB>18.8 predicted poor survival for individuals in stages 2 and 3.

Abstract Background Radical pancreaticoduodenectomy is the most common treatment strategy for patients diagnosed with adenocarcinoma of the pancreatic head. Few studies have reported the clinical characteristics and treatment efficacies of patients undergoing radical pancreaticoduodenectomy for adenocarcinoma of the pancreatic head. Methods A total of 177 pancreatic head cancer patients who underwent radical pancreaticoduodenectomy and were pathologically confirmed as having pancreatic ductal adenocarcinoma were screened in the West China Hospital of Sichuan University. The multivariate analysis results were implemented to construct a nomogram. The concordance index (c-index), the area under the curve (AUC) and calibration were utilized to evaluate the predictive performance of the nomogram. Results The prognostic nutritional index (PNI), the lymph node ratio (LNR) and the American Joint Committee on Cancer (AJCC) staging served as independent prognostic factors and were used to construct the nomogram. The c-indexes of the nomogram were 0.799 (confidence interval (CI), 0.741–0.858) and 0.732 (0.657–0.807) in the primary set and validation set, respectively. The AUCs of the nomogram at 1 and 3 years were 0.832 and 0.783, which were superior to the AJCC staging values of 0.759 and 0.705, respectively. Conclusions The nomogram may be used to predict the prognosis of radical resection for adenocarcinoma of the pancreatic head. These findings may represent an effective model for the developing an optimal therapeutic schedule for malnourished patients who need early effective nutritional intervention and may promote the treatment efficacy of resectable adenocarcinoma of the pancreatic head.

Abstract Background Although genes have been previously detected in pancreatic cancer (PC), aberrant genes that play roles in resectable pancreatic cancer should be further assessed. Methods Messenger RNA samples and clinicopathological data corrected with PC were downloaded from The Cancer Genome Atlas (TCGA). Resectable PC patients were randomly divided into a primary set and a validation set. Univariable Cox regression analysis, lasso-penalized Cox regression analysis, and multivariable Cox analysis were implemented to distinguish survival-related genes (SRGs). A risk score based on the SRGs was calculated by univariable Cox regression analysis. A genomic-clinical nomogram was established by integrating the risk score and clinicopathological data to predict overall survival (OS) in resectable PC. Results Five survival-related genes (AADAC, DEF8, HIST1H1C, MET, and CHFR) were significantly correlated with OS in resectable PC. The resectable PC patients, based on risk score, were sorted into a high-risk group that showed considerably unfavorable OS (p

Fluoroquinolone (FQ) resistance in a major foodborne bacterial pathogen, Campylobacter jejuni, derived from cattle has recently become prevalent and poses a significant public health concern. However, the underlying factors for this increase are not entirely clear. To evaluate the effect of enrofloxacin treatment on FQ-resistance development in C. jejuni, 35 commercial calves were equally divided into five groups (Groups 1–5) and were orally inoculated with FQ-susceptible (FQ-S) C. jejuni. Eight days later, Groups 4 and 5 were challenged with Mannheimia haemolytica via a transtracheal route to induce a respiratory disease; after 8 days, Groups 2, 3, 4, and 5 were injected subcutaneously with enrofloxacin (7.5 mg/kg for Groups 2 and 4, and 12.5 mg/kg for Groups 3 and 5). Colonization levels by FQ-resistant (FQ-R) and FQ-S Campylobacter in rectal feces were determined via differential culture throughout the experiment. Before oral inoculation with C. jejuni, only five calves were naturally colonized by Campylobacter, four of which were also colonized by FQ-R C. jejuni (three in Group 1 and one in Group 3). Soon after the oral inoculation, almost all calves in the groups became stably colonized by FQ-S C. jejuni (~3–6 log10 CFU/g), except that the four calves that were pre-colonized before inoculation remained positive with both FQ-R and FQ-S C. jejuni. Following enrofloxacin administration, C. jejuni colonization declined sharply and rapidly in all treated groups to undetectable levels; however, the vast majority of the animals were recolonized by C. jejuni at comparable levels 72 h after the treatment. Notably, no FQ-R C. jejuni was detected in any of the calves that received enrofloxacin, regardless of the drug dose used or disease status of the animals. The lack of detection of FQ-R C. jejuni was likely due to the localized high concentration of the antibiotic in the intestine, which may have prevented the emergence of the FQ-R mutant. These findings indicate that single-dose enrofloxacin use in cattle poses a low risk for selection of de novo FQ-R mutants in C. jejuni.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a public health concern worldwide, but comprehensive analysis of risk factors for CRPA remains limited in China. We conducted a retrospective observational study of carbapenem resistance in 71,880 P. aeruginosa isolates collected in Zhejiang Province during 2015–2017. We analyzed risk factors for CRPA, including the type of clinical specimen; the year, season, and region in which it was collected; patient information, including age, whether they were an outpatient or inpatient, and whether inpatients were in the intensive care unit or general ward; and the level of hospital submitting isolates. We found CRPA was more prevalent among isolates from patients >60 years of age and in inpatients, especially in intensive care units. In addition, specimen types and seasons in which they were collected were associated with higher rates of CRPA. Our findings can help hospitals reduce the spread of P. aeruginosa and optimize antimicrobial drug use.

Health care-associated infections, also known as nosocomial infections, are the most frequent adverse events in health care delivery worldwide, causing high rates of morbidity and mortality and high health care costs. Pseudomonas aeruginosa

Consumption of contaminated poultry products is one of the main sources of human campylobacteriosis, of which Campylobacter jejuni subsp. jejuni (C. jejuni) and C. coli are responsible for ~98% of the cases. In turkeys, the ceca are an important anatomical site where Campylobacter asymptomatically colonizes. We previously demonstrated that commercial turkey poults colonized by C. jejuni showed acute changes in cytokine gene expression profiles, and histological intestinal lesions at 2 days post-inoculation (dpi). Cecal tonsils (CT) are an important part of the gastrointestinal-associated lymphoid tissue that surveil material passing in and out of the ceca, and generate immune responses against intestinal pathogens. The CT immune response toward Campylobacter remains unknown. In this study, we generated a kanamycin-resistant C. coli construct (CcK) to facilitate its enumeration from cecal contents after experimental challenge. In vitro analysis of CcK demonstrated no changes in motility when compared to the parent isolate. Poults were inoculated by oral gavage with CcK (5 × 107 colony forming units) or sterile-media (mock-colonized), and euthanized at 1 and 3 dpi. At both time points, CcK was recovered from cecal contents, but not from the mock-colonized group. As a marker of acute inflammation, serum alpha-1 acid glycoprotein was significantly elevated at 3 dpi in CcK inoculated poults compared to mock-infected samples. Significant histological lesions were detected in cecal and CT tissues of CcK colonized poults at 1 and 3 dpi, respectively. RNAseq analysis identified 250 differentially expressed genes (DEG) in CT from CcK colonized poults at 3 dpi, of which 194 were upregulated and 56 were downregulated. From the DEG, 9 significantly enriched biological pathways were identified, including platelet aggregation, response to oxidative stress and negative regulation of oxidative stress-induced intrinsic apoptotic signaling pathway. These data suggest that C. coli induced an acute inflammatory response in the intestinal tract of poults, and that platelet aggregation and oxidative stress in the CT may affect the turkey's ability to resist Campylobacter colonization. These findings will help to develop and test Campylobacter mitigation strategies to promote food safety in commercial turkeys.

The purpose of this study was to evaluate the pharmacokinetics of tulathromycin in the plasma and maternal and fetal tissues of pregnant ewes when administered within 24 hours of a single, IV Campylobacter jejuni (C. jejuni) challenge. Twelve, pregnant ewes between 72-92 days of gestation were challenged IV with C. jejuni IA3902 and then treated with 1.1 ml/45.36 kg of tulathromycin subcutaneously 18 hours post-challenge. Ewes were bled at predetermined time points and euthanized either at a predetermined time point or following the observation of vaginal bleeding or abortion. Following euthanasia, tissues were collected for bacterial culture, pharmacokinetics and histologic examination. The maximum (geometric) mean tulathromycin plasma concentration was estimated at 0.302 μg/mL, with a peak level observed at around 1.2 hours. The apparent systemic clearance of tulathromycin was estimated at 16.6 L/h (or 0.28 L/kg/h) with an elimination half-life estimated at approximately 22 hours. The mean tissue concentrations were highest in the uterus (2.464 μg/g) and placentome (0.484 μg/g), and were lowest in fetal liver (0.11 μg/g) and fetal lung (0.03 μg/g). Compared to previous reports, results of this study demonstrate that prior IV administration of C. jejuni appeared to substantially alter the pharmacokinetics of tulathromycin, reducing both the peak plasma concentrations and elimination half-life. However, additional controlled trials are required to confirm those observations.

Campylobacter is a leading cause of foodborne gastroenteritis. Recent studies have indicated a rise in fluoroquinolone-resistant (FQ-R) Campylobacter in cattle, where FQ is used to control bovine respiratory disease (BRD). To assess the effect of danofloxacin treatment on the development of FQ-resistance in C. jejuni, 30 commercial calves were divided into Group 1, Group 2, and Group 3 (n = 10), and were all inoculated orally with FQ-susceptible (FQ-S) C. jejuni; seven days later, Group 3 was challenged with transtracheal Mannheimia haemolytica, and one week later, Group 2 and Group 3 were injected subcutaneously with danofloxacin. Rectal feces were collected to determine relative percentages of FQ-R Campylobacter via culture. Before oral inoculation with C. jejuni, 87% of calves were naturally colonized by FQ-R C. jejuni. Two days after the inoculation, FQ-R C. jejuni decreased substantially in the majority of calves. Within 24 h of danofloxacin injection, almost all C. jejuni populations shifted to an FQ-R phenotype in both FQ-treated groups, which was only transitory, as FQ-S strains became predominant during later periods. Genotyping indicated that the spike seen in FQ-R C. jejuni populations following the injection was due mainly to enrichment of preexisting FQ-R C. jejuni, rather than development of de novo FQ resistance in susceptible strains. These results provide important insights into the dynamic changes of FQ-resistant Campylobacter in cattle in response to FQ treatment.

Previous studies have identified oral administration of antibiotics and gut-impacting drugs as critical drivers for fecal antibiotic resistance (AR) and microbiome disruption in lab mice, but the practical implications of these findings have yet to be validated in hosts nurtured in conventional environment. Using ampicillin (Amp) as a way to extrapolate the general effect of antibiotics, this project examined the impact of drug administration routes on fecal microbiota and resistome using poultry raised in a teaching farm. AR genes were found to be abundant in the feces of young Leghorn chicks without previous antibiotic treatment. In chickens seeded with blaCMY–2+Escherichia coli, 300 mg/kg body weight of Amp was orally administered for 5 days. This led to the fecal microbiota switching from Firmicutes occupied (95.60 ± 2.62%) and Lactobacillus rich, to being dominated by Proteobacteria (70.91 ± 28.93%), especially Escherichia/Shigella. However, when Amp was given via muscle injection, Firmicutes was mostly retained (i.e., from 83.6 ± 24.4% pre- to 90.4 ± 15.2% post-treatment). In control chickens without seeding with blaCMY–2+E. coli, oral Amp also led to the increase of Proteobacteria, dominated by Klebsiella and Escherichia/Shigella, and a reduction of Firmicutes. Specifically within Firmicutes, Enterococcus, Clostridium, etc. were enriched but Lactobacillus was diminished. The fecal resistome including Ampr genes was more abundant in chickens receiving oral Amp than those treated with muscle injection, but the difference was primarily within 1 log. The data illustrated that both drug administration routes and pre-existing gut microbiota have profound impacts on gut microbiome disruption when antibiotic treatment is given. In hosts nurtured in a conventional environment, drug administration route has the most evident impact on gut microbiota rather than the size of the targeted blaCMY–2+ gene pool, likely due to the pre-existing bacteria that are (i) less susceptible to Amp, and/or (ii) with Ampr- or multidrug resistance-encoding genes other than blaCMY–2+. These results demonstrated the critical interplay among drug administration routes, microbiota seeded through the gastrointestinal tract, AR, gut microbiota disruption, and the rise of common opportunistic pathogens in hosts. The potential implications in human and animal health are discussed.

Abstract IncX4 plasmids are associated with the dissemination of the mcr-1 genes in Enterobacteriaceae. We screened IncX4 plasmids among 2,470 isolates of Enterobacteriaceae and determined the mcr-1 positive isolates. Forty-three isolates were observed to carry IncX4 type plasmid, among which 13 were identified to carry mcr-1 gene. Three representative mcr-1-positive IncX4 plasmids were selected for high-throughput sequencing. Comparative genomics showed that the mcr-1-carrying IncX4 plasmids exhibit remarkable similarity in the backbone, and the major distinction lies in the region containing mcr-1. The major variable regions of all the IncX4 plasmids were fully characterized by PCR-RFLP. The results revealed that the mcr-1 was located on the Variable Region I of IncX4 plasmids in 11 E. coli isolates. Among them, nine E. coli strains possess an epidemic pCSZ4-like IncX4 plasmid containing mcr-1. ISApl1 was presumably involved in the transposition of the mcr-1 cassette and then was lost. Similar genetic contexts were found in different plasmids, even the E. coli chromosome, implying the acquisition of mcr-1 by a unique common mechanism.

Abstract Antibiotic resistance, particularly to fluoroquinolones and macrolides, in the major foodborne pathogen Campylobacter is considered a serious threat to public health. Although ruminant animals serve as a significant reservoir for Campylobacter, limited information is available on antibiotic-resistant Campylobacter of bovine origin. Here, we analyzed the antimicrobial susceptibilities of 320 C. jejuni and 115 C. coli isolates obtained from feedlot cattle farms in multiple states in the U.S. The results indicate that fluoroquinolone resistance reached to 35.4% in C. jejuni and 74.4% in C. coli, which are significantly higher than those previously reported in the U.S. While all fluoroquinolone resistant (FQR) C. coli isolates examined in this study harbored the single Thr-86-Ile mutation in GyrA, FQR C. jejuni isolates had other mutations in GyrA in addition to the Thr-86-Ile change. Notably, most of the analyzed FQR C. coli isolates had similar PFGE (pulsed field gel electrophoresis) patterns and the same MLST (multilocus sequence typing) sequence type (ST-1068) regardless of their geographic sources and time of isolation, while the analyzed C. jejuni isolates were genetically diverse, suggesting that clonal expansion is involved in dissemination of FQR C. coli but not C. jejuni. These findings reveal the rising prevalence of FQR Campylobacter in the U.S. and provide novel information on the epidemiology of antibiotic-resistant Campylobacter in the ruminant reservoir.

To aid development of phage therapy against Campylobacter, we investigated the distribution of the clustered regularly interspaced short palindromic repeats (CRISPR) systems in fluoroquinolone (FQ)-resistant Campylobacter jejuni. A total of 100 FQ-resistant C. jejuni strains from different sources were analyzed by PCR and DNA sequencing to determine resistance-conferring mutation in the gyrA gene and the presence of various CRISPR systems. All but one isolate harbored 1–5 point mutations in gyrA, and the most common mutation was the Thr86Ile change. Ninety-five isolates were positive with the CRISPR PCR, and spacer sequences were found in 86 of them. Among the 292 spacer sequences identified in this study, 204 shared 93–100% nucleotide homology to Campylobacter phage D10, 44 showed 100% homology to Campylobacter phage CP39, and 3 had 100% homology with Campylobacter phage CJIE4-5. The remaining 41 spacer sequences did not match with any phages in the database. Based on the results, it was inferred that the FQ-resistant C. jejuni isolates analyzed in this study were potentially resistant to Campylobacter phages D10, CP39, and CJIE4-5 as well as some unidentified phages. These phages should be excluded from cocktails of phages that may be utilized to treat FQ-resistant Campylobacter.

Single-minded homolog 2 (SIM2) has been identified as a potential contributor to the development of solid tumors. Despite this, there is a lack of comprehensive research regarding its biological role and underlying mechanism within pancreatic cancer (PC), as well as its prognostic impact. This study systematically evaluated the expression level and clinical significance of SIM2 in patients with PC using various databases, including The Cancer Genome Atlas, KM Plotter, and gene expression profiling interactive analysis. To investigate the relationship between SIM2 expression and immune cell infiltration, we conducted ESTIMATE and single-sample gene set enrichment analysis (ssGSEA) analyses. Single-minded homolog 2 was up-regulated in patients with PC. Pancreatic cancer patients with higher SIM2 expression had poorer overall survival rates. Gene set enrichment analysis results suggested that SIM2 may have a significant impact on the progression of PC and the regulation of immune responses. According to the ssGSEA algorithm, SIM2 has a negative correlation with the levels of infiltrating TFH, mast cells, and pDC. Our study demonstrated that SIM2 serves as a biomarker, and is associated with both prognosis and immune infiltration in PC. This provides a solid foundation for future investigations into the precise role of SIM2 in the carcinogenesis and progression of PC. [ABSTRACT FROM AUTHOR]

Campylobacter jejuni clone SA has emerged as the predominant cause of ovine abortion outbreaks in the United States (US). Despite the fact that commercial Campylobacter vaccines are available, their efficacy in protecting abortion induced by C. jejuni clone SA is uncertain, and a protective vaccine is needed to control the disease. In this study, an experimental homologous bacterin (made of a clone SA isolate) and two commercial Campylobacter vaccines were evaluated for their protection against C. jejuni clone SA-induced sheep abortion. All vaccines induced high levels of antibodies against C. jejuni clone SA in pregnant ewes, but only the experimental homologous bacterin produced significant protection (80%). Immunoblotting showed that the experimental vaccine elicited more specific antibodies against C. jejuni clone SA. These findings strongly suggest the necessity of developing a homologous vaccine for the control C. jejuni clone SA induced abortion on sheep farms.

ABSTRACT The recent emergence of a transferable colistin resistance mechanism, MCR-1, has gained global attention because of its threat to clinical treatment of infections caused by multidrug-resistant Gram-negative bacteria. However, the possible transmission route of mcr-1 among Enterobacteriaceae species in clinical settings is largely unknown. Here, we present a comprehensive genomic analysis of Escherichia coli isolates collected in a hospital in Hangzhou, China. We found that mcr-1-carrying isolates from clinical infections and feces of inpatients and healthy volunteers were genetically diverse and were not closely related phylogenetically, suggesting that clonal expansion is not involved in the spread of mcr-1. The mcr-1 gene was found on either chromosomes or plasmids, but in most of the E. coli isolates, mcr-1 was carried on plasmids. The genetic context of the plasmids showed considerable diversity as evidenced by the different functional insertion sequence (IS) elements, toxin-antitoxin (TA) systems, heavy metal resistance determinants, and Rep proteins of broad-host-range plasmids. Additionally, the genomic analysis revealed nosocomial transmission of mcr-1 and the coexistence of mcr-1 with other genes encoding β-lactamases and fluoroquinolone resistance in the E. coli isolates. These findings indicate that mcr-1 is heterogeneously disseminated in both commensal and pathogenic strains of E. coli, suggest the high flexibility of this gene in its association with diverse genetic backgrounds of the hosts, and provide new insights into the genome epidemiology of mcr-1 among hospital-associated E. coli strains. IMPORTANCE Colistin represents one of the very few available drugs for treating infections caused by extensively multidrug-resistant Gram-negative bacteria. The recently emergent mcr-1 colistin resistance gene threatens the clinical utility of colistin and has gained global attention. How mcr-1 spreads in hospital settings remains unknown and was investigated by whole-genome sequencing of mcr-1-carrying Escherichia coli in this study. The findings revealed extraordinary flexibility of mcr-1 in its spread among genetically diverse E. coli hosts and plasmids, nosocomial transmission of mcr-1-carrying E. coli, and the continuous emergence of novel Inc types of plasmids carrying mcr-1 and new mcr-1 variants. Additionally, mcr-1 was found to be frequently associated with other genes encoding β-lactams and fluoroquinolone resistance. These findings provide important information on the transmission and epidemiology of mcr-1 and are of significant public health importance as the information is expected to facilitate the control of this significant antibiotic resistance threat.

Weaning is one of the most stressful challenges in the pig’s life, which contributes to dysfunctions of intestinal and immune system, disrupts the gut microbial ecosystem, and therefore compromises the growth performance and health of piglets. To mitigate the negative impact of the stress on early-weaned piglets, effective measures are needed to promote gut health. Toward this end, we tamed a Saccharomyces cerevisiae strain and developed a probiotic Duan-Nai-An, which is a yeast culture of the tamed S. cerevisiae on egg white. In this study, we tested the performance of Duan-Nai-An on growth and health of early-weaned piglets and analyzed its impact on fecal microbiota. The results showed that Duan-Nai-An significantly improved weight gain and feed intake, and reduced diarrhea and death of early-weaned piglets. Analysis of the gut microbiota showed that the bacterial community was shaped by Duan-Nai-An and maintained as a relatively stable structure, represented by a higher core OTU number and lower unweighted UniFrac distances across the early weaned period. However, fungal community was not significantly shaped by the yeast probiotics. Notably, 13 bacterial genera were found to be associated with Duan-Nai-An feeding, including Enterococcus, Succinivibrio, Ruminococcus, Sharpea, Desulfovibrio, RFN20, Sphaerochaeta, Peptococcus, Anaeroplasma, and four other undefined genera. These findings suggest that Duan-Nai-An has the potential to be used as a feed supplement in swine production.

Streptococcus suis is a previously neglected, newly emerging multidrug-resistant zoonotic pathogen. Mobile genetic elements (MGEs) play a key role in intra- and interspecies horizontal transfer of antimicrobial resistance (AMR) determinants. Although previous studies showed the presence of several MGEs, a comprehensive analysis of AMR-associated mobilome as well as their interaction and evolution has not been performed. In this study, we presented the AMR-associated mobilome and their insertion hotspots in S. suis. Integrative conjugative elements (ICEs), prophages and tandem MGEs were located at different insertion sites, while 86% of the AMR-associated MGEs were inserted at rplL and rum loci. Comprehensive analysis of insertions at rplL and rum loci among four pathogenic Streptococcus species (Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes, and S. suis) revealed the existence of different groups of MGEs, including Tn5252, ICESp1108, and TnGBS2 groups ICEs, Φm46.1 group prophage, ICE_ICE and ICE_prophage tandem MGEs. Comparative ICE genomics of ICESa2603 family revealed that module exchange and acquisition/deletion were the main mechanisms in MGEs’ expansion and evolution. Furthermore, the observation of tandem MGEs reflected a novel mechanism for MGE diversity. Moreover, an in vitro competition assay showed no visible fitness cost was observed between different MGE-carrying isolates and a conjugation assay revealed the transferability of ICESa2603 family of ICEs. Our statistics further indicated that the prevalence and diversity of MGEs in S. suis is much greater than in other three species which prompted our hypothesis that S. suis is probably a MGEs reservoir for other streptococci. In conclusion, our results showed that acquisition of MGEs confers S. suis not only its capability as a multidrug resistance pathogen, but also represents a paradigm to study the modular evolution and matryoshkas of MGEs.

The aim of the study was to investigate the mode of action of (-)-α-pinene in terms of its modulation of antibiotic resistance in Campylobacter jejuni. Broth microdilution and ethidium bromide accumulation assays were used to evaluate the (-)-α-pinene antimicrobial activity, modulation of antimicrobial resistance, and inhibition of antimicrobial efflux. The target antimicrobial efflux systems were identified using an insertion mutagenesis approach, and C. jejuni adaptation to (-)-α-pinene was evaluated using DNA microarrays. Knock-out mutants of the key up-regulated transcriptional regulators hspR and hrcA were constructed to investigate their roles in C. jejuni adaptation to several stress factors, including osmolytes, and pH, using Biolog phenotypical microarrays. Our data demonstrate that (-)-α-pinene efficiently modulates antibiotic resistance in C. jejuni by decreasing the minimum inhibitory concentrations of ciprofloxacin, erythromycin and triclosan by up to 512-fold. Furthermore, (-)-α-pinene promotes increased expression of cmeABC and another putative antimicrobial efflux gene, Cj1687. The ethidium bromide accumulation was greater in the wild-type strain than in the antimicrobial efflux mutant strains, which indicates that these antimicrobial efflux systems are a target of action of (-)-α-pinene. Additionally, (-)-α-pinene decreases membrane integrity, which suggests that enhanced microbial influx is a secondary mode of action of (-)-α-pinene. Transcriptomic analysis indicated that (-)-α-pinene disrupts multiple metabolic pathways, and particularly those involved in heat-shock responses. Thus, (-)-α-pinene has significant activity in the modulation of antibiotic resistance in C. jejuni, which appears to be mediated by multiple mechanisms that include inhibition of microbial efflux, decreased membrane integrity, and metabolic disruption. These data warrant further studies on (-)-α-pinene to develop its use in the control of antibiotic resistance in Campylobacter.