Molecular epidemiology of Acinetobacter baumannii during COVID-19 at a hospital in northern China.

BACKGROUND: The wide spread of carbapenem-resistance clones of Acinetobacter baumannii has made it a global public problem. Some studies have shown that the prevalence of Acinetobacter baumannii clones can change over time. However, few studies with respect to the change of epidemiological clones in Acinetobacter baumannii during Corona Virus Disease 2019 (COVID-19) were reported. This study aims to investigate the molecular epidemiology and resistance mechanisms of Acinetobacter baumannii during COVID-19. RESULTS: A total of 95 non-replicated Acinetobacter baumannii isolates were enrolled in this study, of which 60.0% (n = 57) were identified as carbapenem-resistant Acinetobacter baumannii (CRAB). The positive rate of the blaOXA-23 gene in CRAB isolates was 100%. A total of 28 Oxford sequence types (STs) were identified, of which the most prevalent STs were ST540 (n = 13, 13.7%), ST469 (n = 13, 13.7%), ST373 (n = 8, 8.4%), ST938 (n = 7, 7.4%) and ST208 (n = 6, 6.3%). Differently, the most widespread clone of Acinetobacter baumannii in China during COVID-19 was ST208 (22.1%). Further study of multidrug-resistant ST540 showed that all of them were carrying blaOXA-23, blaOXA-66, blaADC-25 and blaTEM-1D, simultaneously, and first detected Tn2009 in ST540. The blaOXA-23 gene was located on transposons Tn2006 or Tn2009. In addition, the ST540 strain also contains a drug-resistant plasmid with msr(E), armA, sul1 and mph(E) genes. CONCLUSION: The prevalent clones of Acinetobacter baumannii in our organization have changed during COVID-19, which was different from that of China. ST540 strains which carried multiple drug-resistant mobile elements was spreading, indicating that it is essential to strengthen the molecular epidemiology of Acinetobacter baumannii.

Replicon-Based Typing About IncG Plasmids and Molecular Characterization of Five IncG Plasmids Carrying Carbapenem Resistance Gene bla KPC-2.

Purpose: To investigate the genetic diversity of IncG plasmids, we have proposed a typing scheme based on replicon repA and performed comparative genomic analysis of five IncG plasmids from China. Methods: p30860-KPC, p116965-KPC, pA1705-KPC, pA1706-KPC and pNY5520-KPC total in five IncG plasmids from clinical isolates of Pseudomonas and Enterobacteriaceae, respectively, were fully sequenced and were compared with the previously collected reference plasmid p10265-KPC. Results: Based on phylogeny, IncG-type plasmids are divided into IncG-I to IncG-VIII, the five plasmids belong to IncG-VIII. A detailed sequence comparison was then presented that the IncG plasmid involved accessory region I (Tn5563a/b/c/d/e), accessory region II (ISpa19), and accessory region III (bla KPC-2-region). Expect for the pNY5520-KPC, the rest of the plasmids had the same backbone structure as the reference one. Within the plasmids, insertion sequences Tn5563d and Tn5563e were identified, a novel unknown insertion region was found in Tn5563b/c/d/e. In addition, Tn6376b and Tn6376c were newly designated in the study. Conclusion: The data presented here including a typing scheme and detailed genetic comparison which provide an insight into the diversification and evolution history of IncG plasmids.

Omicron neutralization character in patients with breast cancer and liver cancer after the nationwide omicron outbreak.

BACKGROUND: The surge in omicron variants has caused nationwide breakthrough infections in mainland China since the December 2022. In this study, we report the neutralization profiles of serum samples from the patients with breast cancer and the patients with liver cancer who had contracted subvariant breakthrough infections. METHODS: In this real-world study, we enrolled 143 COVID-19-vaccinated (81 and 62 patients with breast and liver cancers) and 105 unvaccinated patients with cancer (58 and 47 patients with breast and liver cancers) after omicron infection. Anti-spike receptor binding domain (RBD) IgGs and 50% pseudovirus neutralization titer (pVNT50) for the preceding (wild type), circulating omicron (BA.4-BA.5, and BF.7), and new subvariants (XBB.1.5) were comprehensively analyzed. RESULTS: Patients with liver cancer receiving booster doses had higher levels of anti-spike RBD IgG against circulating omicron (BA.4-BA.5, and BF.7) and a novel subvariant (XBB.1.5) compared to patients with breast cancer after breakthrough infection. Additionally, all vaccinated patients produced higher neutralizing antibody titers against circulating omicron (BA.4-BA.5, and BF.7) compared to unvaccinated patients. However, the unvaccinated patients produced higher neutralizing antibody against XBB.1.5 than vaccinated patients after Omicron infection, with this trend being more pronounced in breast cancer than in liver cancer patients. Moreover, we found that there was no correlation between anti-spike RBD IgG against wildtype virus and the neutralizing antibody titer, but a positive correlation between anti-spike RBD IgG and the neutralizing antibody against XBB.1.5 was found in unvaccinated patients. CONCLUSION: Our study found that there may be differences in vaccine response and protective effect against COVID-19 infection in patients with liver and breast cancer. Therefore, we recommend that COVID-19 vaccine strategies should be optimized based on vaccine components and immunology profiles of different patients with cancer.

HBeAg induces neutrophils activation impairing NK cells function in patients with chronic hepatitis B.

BACKGROUND: The role of neutrophils in hepatitis B virus (HBV) infection has been a subject of debate due to their involvement in antiviral responses and immune regulation. This study aimed to elucidate the neutrophil characteristics in patients with chronic hepatitis B (CHB). METHODS: Through flow cytometry and ribonucleic acid-sequencing analysis, the phenotypes and counts of neutrophils were analyzed in patients with CHB. Moreover, the effects of HBeAg on neutrophils and the corresponding pattern recognition receptors were identified. Simultaneously, the cross-talk between neutrophils and natural killer (NK) cells was investigated. RESULTS: Neutrophils were activated in patients with CHB, characterized by higher expression levels of programmed death-ligand 1 (PD-L1), cluster of differentiation 86, and interleukin-8, and lower levels of CXC motif chemokine receptor (CXCR) 1 and CXCR2. Hepatitis B e antigen (HBeAg) partially induces neutrophil activation through the Toll-like receptor 2 (TLR2). A consistent upregulation of the TLR2 and HBeAg expression was observed in patients with CHB. Notably, the genes encoding molecules pivotal for NK-cell function upon NK receptor engagement enriched in neutrophils after HBeAg activation. The HBeAg-activated neutrophils demonstrated the ability to decrease the production of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) in NK cells, while the PD-1 and PD-L1 pathways partially mediated the immunosuppression. CONCLUSIONS: The immunosuppression of neutrophils induced by HBeAg suggests a novel pathogenic mechanism contributing to immune tolerance in patients with CHB.

Clinical features, microbial spectrum, and antibiotic susceptibility patterns of spontaneous bacterial peritonitis in cirrhotic patients.

BACKGROUND AND AIMS: The microbial spectrum and antimicrobial resistance patterns change over time and vary across regions in patients with spontaneous bacterial peritonitis (SBP). There is an urgent need to clarify the factors associated with in-hospital mortality in these patients. METHODS: In this study, 377 patients with SBP and 794 patients with bacterascites were analyzed for the microbial spectrum, antimicrobial resistance profiles, and laboratory findings. RESULTS: The most common pathogens were Escherichia coli (96, 25.5%), Staphylococcus epidermidis (55, 14.6%), and Enterococcus faecium (42, 11.1%). Multidrug-resistant (MDR) bacteria comprised 49.7% of gram-positive bacteria (GPB) and 48.8% of gram-negative bacteria (GNB). The most sensitive antibiotics were amikacin (91.5%), meropenem (89.8%) and piperacillin/tazobactam (87.6%). Extensively drug-resistant (XDR) (OR=51.457, p < 0.001), neutrophil count (OR=1.088, p < 0.001), and the model for end-stage liver disease (MELD) score (OR=1.124, p < 0.001) were independent predictive factors of in-hospital mortality in patients with SBP. CONCLUSION: MDR represented nearly half of the bacteria isolated from patients with SBP, of which the high prevalence of extended-spectrum ß-lactamase-producing and Carbapenem-resistant bacteria is concerning. The presence of XDR, higher MELD score, and neutrophil count were independent predictive factors associated with higher in-hospital mortality in patients with SBP, indicating that intensive care should be provided to these patients.

Acinetobacter baumannii adaptation to the host pH microenvironment is mediated by allelic variation in a single residue of BauA protein.

Acinetobacter baumannii has been listed as one of the most critical pathogens in nosocomial infections; however, the key genes and mechanisms to adapt to the host microenvironment lack in-depth understanding. In this study, a total of 76 isolates (from 8 to 12 isolates per patient, spanning 128 to 188 days) were longitudinally collected from eight patients to investigate the within-host evolution of A. baumannii. A total of 70 within-host mutations were identified, 80% of which were nonsynonymous, indicating the important role of positive selection. Several evolutionary strategies of A. baumannii to increase its potential to adapt to the host microenvironment were identified, including hypermutation and recombination. Six genes were mutated in isolates from two or more patients, including two TonB-dependent receptor genes (bauA and BJAB07104_RS00665). In particular, the siderophore receptor gene bauA was mutated in multiple isolates from four patients with three MLST types, and all mutations were at amino acid 391 in ligand-binding sites. With 391T or 391A, BauA was more strongly bound to siderophores, which promoted the iron-absorption activity of A. baumannii at acidic or neutral pH, respectively. Through the A/T mutation at site 391 of BauA, A. baumannii displayed two reversible phases to adapt to distinct pH microenvironments. In conclusion, we demonstrated the comprehensive within-host evolutionary dynamics of A. baumannii, and discovered a key mutation of BauA site 391 as a genetic switch to adapt to different pH values, which may represent a model in the pathogen evolutionary adaption of the host microenvironment.

[Construction and application of lentivirus overexpression vector with two labeling genes fused with CopGFP and PuroR].

Objective: To construct the lentivirus overexpression vector with two label genes fused with CopGFP and PuroR and to detect the emission of green fluorescence as well as resistance to puromycin in liver cancer cells infected with lentivirus packaged with the above vector. Methods: Firstly, two fragments containing copGFP and PuroR coding sequences were amplified from pCDH-CMV-MCS-copGFP and pLKO.1 respectively; secondly, the two amplified regions were fused with each other by recombinant PCR; thirdly, the fusion DNA fragment was cut and inserted into pCDH-CMV-MCS-copGFP vector, which was linearized with the same restriction endonuclease as used to digest fusion DNA fragment: BamH Ⅰ and Sal Ⅰ. The fusion region in the constructed vector was confirmed by DNA sequencing. The checked vector was co-transfected with package assistant plasmids, namely PLP1, PLP2 and VSVG into in 293T cells and the culture supernatant was subjected to centrifuge and infect liver cancer MHCC97H cells, which were then used to detect their resistance to puromycin (infected cells were treated with 1 mg/ml puromycin for 7 days after infection) and to observe green fluorescence emission in microscope. To determine its efficiency in expressing foreign target protein, the Sp1 coding region was inserted into the MCS sites of the vector, and Sp1 mRNA and protein expression levels were compared with the vehicle vector by RT-qPCR and Western blot. Results: The lentivirus overexpression vector with two label genes fused with CopGFP and PuroR was successfully constructed, and the liver cancer cells infected with lentivirus packaged with the vector expressing two labeling genes fused with CopGFP and PuroRshowed both emission of green fluorescence and resistance to puromycin simultaneously, while cells containing with the vector inserted with Sp1 coding region improved Sp1 mRNA level with 3.3 fold and protein level with 2.2 fold higher in comparison with cells containing the vehicle vector (P＜0.01). Conclusion: The fused label genes consisting of copGFP and PuroR are correctly cloned into the lentivirus vector and confer cells with the ability to emission of green fluorescence and resistance to puromycin, besides, the vector may promote the expression of the target gene with long coding sequence.

Genetic Characterization of Four Groups of Chromosome-Borne Accessory Genetic Elements Carrying Drug Resistance Genes in Providencia.

Purpose: The aim of this study was to gain a deeper genomics and bioinformatics understanding of diversification of accessory genetic elements (AGEs) in Providencia. Methods: Herein, the complete genome sequences of five Providencia isolates from China were determined, and seven AGEs were identified from the chromosomes. Detailed genetic dissection and sequence comparison were applied to these seven AGEs, together with additional 10 chromosomal ones from GenBank (nine of them came from Providencia). Results: These 17 AGEs were divided into four groups: Tn6512 and its six derivatives, Tn6872 and its two derivatives, Tn6875 and its one derivative, and Tn7 and its four derivatives. These AGEs display high-level diversification in modular structures that had complex mosaic natures, and particularly different multidrug resistance (MDR) regions were presented in these AGEs. At least 52 drug resistance genes, involved in resistance to 15 different categories of antimicrobials and heavy metal, were found in 15 of these 17 AGEs. Conclusion: Integration of these AGEs into the Providencia chromosomes would contribute to the accumulation and distribution of drug resistance genes and enhance the ability of Providencia isolates to survive under drug selection pressure.

Listeriosis Cases and Genetic Diversity of Their L. monocytogenes Isolates in China, 2008-2019.

Listeriosis, caused by Listeria monocytogenes, is a severe food-borne infection. The nationwide surveillance in China concerning listeriosis is urgently needed. In the present study, 144 L. monocytogenes isolates were collected from the samples of blood, cerebrospinal fluid (CSF), and fetal membrane/placenta in China for 12 years from 2008 to 2019. We summarized these listeriosis patients' demographical and clinical features and outcomes. The susceptibility profile for 12 antibiotics was also determined by the broth microdilution method. Multilocus sequence typing (MLST) and serogroups of these listeria isolates were analyzed to designate epidemiological types. We enrolled 144 cases from 29 healthcare centers, including 96 maternal-neonatal infections, 33 cases of bacteremia, 13 cases of neurolisteriosis, and two cutaneous listeriosis. There were 31 (59.6%) fetal loss in 52 pregnant women and four (9.8%) neonatal death in 41 newborns. Among the 48 nonmaternal-neonatal cases, 12.5% (6/48) died, 41.7% (20/48) were female, and 64.6% (31/48) occurred in those with significant comorbidities. By MLST, the strains were distinguished into 23 individual sequence types (STs). The most prevalent ST was ST87 (49 isolates, 34.0%), followed by ST1 (18, 12.5%), ST8 (10, 6.9%), ST619 (9, 6.3%), ST7 (7, 4.9%) and ST3 (7, 4.9%). Furthermore, all L. monocytogenes isolates were uniformly susceptible to penicillin, ampicillin, and meropenem. In summary, our study highlights a high genotypic diversity of L. monocytogenes strains causing clinical listeriosis in China. Furthermore, a high prevalence of ST87 and ST1 in the listeriosis should be noted.

UPLC-Q-TOF/MS-Based Serum and Urine Metabonomics Study on the Ameliorative Effects of Palmatine on Helicobacter pylori-Induced Chronic Atrophic Gastritis.

OBJECTIVE: The main objective of this study was to investigate the ameliorative effects of Palmatine (Pal) on Helicobacter pylori (H. pylori) induced chronic atrophic gastritis (CAG). METHOD: Body function, serum biochemical indicators and histopathology were used to evaluate the pharmacodynamics of Pal on CAG rats. The target genes expression levels were verified and assessed by RT-PCR and immunohistochemistry (IHC). Moreover, UPLC-Q-TOF/MS analysis based on urine and serum was performed to identify the potential metabolites in the pathological process of CAG induced by H. pylori. Metabolic pathway analysis was performed to elucidate the metabolic network associated with Pal treatment of CAG. RESULTS: Pal (10, 20, 40 mg/kg/day) significantly restored the body function of CAG rats, reduced the serum biochemical indicators, and maintained the integrity of the gastric mucosal epithelial barrier while alleviated gastric histological damage. Metabolomics analysis shows that the therapeutic effect of Pal on CAG involves 10 metabolites and 10 metabolic pathways, of which the Taurine and hypotaurine metabolism, Glycerophospholipid metabolism and Pentose and glucuronate interconversions are closely related to the gastrointestinal protection of Pal, and these metabolic pathways crosstalk with each other due to the internet hub of citric acid cycle. CONCLUSIONS: Metabolomics was used for the first time to identify potential biomarkers of CAG and to illuminate the therapeutic mechanism of Pal on CAG induced by H. pylori. The results provided a new insight for further research on CAG treatment.

Species Distribution and Antifungal Susceptibility of Invasive Candidiasis: A 2016-2017 Multicenter Surveillance Study in Beijing, China.

OBJECTIVE: Invasive candidiasis (IC), a life-threatening fungal infection prevalent among hospitalized patients, has highly variable regional epidemiology. We conducted a multicenter surveillance study to investigate recent trends in species distribution and antifungal susceptibility patterns among IC-associated Candida spp. in Beijing, China, from 2016 to 2017. MATERIALS AND METHODS: A total of 1496 non-duplicate Candida isolates, recovered from blood and other sterile body fluids of IC patients, were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry combined with ribosomal DNA internal transcribed spacer (ITS) region sequencing. Broth microdilution-based susceptibility testing using six antifungal agents was also conducted. RESULTS: Candida albicans was the most frequently isolated species (49.9%), followed by Candida tropicalis (15.5%), Candida glabrata (14.7%) and Candida parapsilosis (14.2%). No significant differences in species distribution were observed when compared with a 2012-2013 dataset. Overall, the rates of susceptibility to fluconazole and voriconazole were high among C. albicans (98% and 97.2%, respectively) and C. parapsilosis species complex (91.1% and 92%, respectively) isolates but low among C. tropicalis (81.5% and 81.1%, respectively) isolates. In addition, the rate of azole resistance among C. tropicalis isolates increased significantly (1.8-fold, P<0.05) compared with that observed in 2012-2013, while micafungin resistance rates were <5% for all tested Candida species. CONCLUSION: Our results suggest that species distribution has remained stable among IC-associated Candida isolates in Beijing. Resistance to micafungin was rare, but increased azole resistance among C. tropicalis isolates was noted. Our study provides information on local epidemiology that will be important for the selection of empirical antifungal agents and contributes to global assessments of antifungal resistance.

Palmatine ameliorates Helicobacter pylori-induced chronic atrophic gastritis by inhibiting MMP-10 through ADAM17/EGFR.

Palmatine (Pal), a plant-based isoquinoline alkaloid, was initially isolated from Coptidis Rhizoma (CR, Huanglian in Chinese) and considered to be a potential non-antibiotic therapeutic agent that can safely and effectively improve Helicobacter pylori (H. pylori) induced chronic atrophic gastritis (CAG). However, underlying mechanisms are unclear. In this study, we explored the protective effect of Pal on H. pylori induced CAG in vivo and in vitro. As a result, Pal alleviated the histological damage of gastric mucosa and the morphological changes of gastric epithelial cell (GES-1) caused by H. pylori. Furthermore, Pal significantly inhibited the expression of EGFR-activated ligand genes, including a disintegrin and metalloproteinase 17 (ADAM17) and heparin-binding epidermal growth factor-like growth factor (HB-EGF), and the proinflammatory factors, such as chemokine 16 (CXCL-16) and interleukin 8 (IL-8), were suppressed. In addition, Pal attenuated inflammatory infiltration of CD8+ T cells while promoted Reg3a expression to enhance host defense. Taken together, we concluded that Pal attenuated the MMP-10 dependent inflammatory response in the gastric mucosa by blocking ADAM17/EGFR signaling, which contributed to its gastrointestinal protective effect.

Mechanism of berberine in treating Helicobacter pylori induced chronic atrophic gastritis through IRF8-IFN-γ signaling axis suppressing.

AIMS: In this study, we will investigate the therapeutic effects of berberine (BBR) in Helicobacter pylori (H. pylori) induced chronic atrophic gastritis (CAG). Furthermore, potential mechanisms of BBR in regulating IRF8-IFN-γ signaling axis will also be investigated. MATERIALS AND METHODS: H. pylori were utilized to establish CAG model of rats. Therapeutic effects of BBR on serum supernatant indices, and histopathology of stomach were analyzed in vivo. Moreover, GES-1 cells were infected by H. pylori, and intervened with BBR in vitro. Cell viability, morphology, proliferation, and quantitative analysis were detected by high-content screening (HCS) imaging assay. To further investigate the potential mechanisms of BBR, relative mRNA, immunohistochemistry and protein expression in IRF8-IFN-γ signaling axis were measured. KEY FINDINGS: Results showed serum supernatant indices including IL-17, CXCL1, and CXCL9 were downregulated by BBR intervention, while, G-17 increased significantly. Histological injuries of gastric mucosa induced by H. pylori also were alleviated. Moreover, cell viability and morphology changes of GES-1 cells were improved by BBR intervention. In addition, proinflammatory genes and IRF8-IFN-γ signaling axis related genes, including Ifit3, Upp1, USP18, Nlrc5, were suppressed by BBR administration in vitro and in vivo. The proteins expression related to IRF8-IFN-γ signaling axis, including Ifit3, IRF1 and Ifit1 were downregulated by BBR intervention.

Clinical and bacteriological features and prognosis of ascitic fluid infection in Chinese patients with cirrhosis.

BACKGROUND: Spontaneous bacterial peritonitis (SBP) and bacterascites (BA) represent frequent and serious complications in cirrhosis patients with ascites. However, few detailed data are available regarding the clinical and bacteriological feature of SBP or BA patients in China. METHODS: We retrospectively analyzed bacteriological and clinical characteristics of patients with SBP and BA at Beijing 302 Hospital in China from January 2012 to December 2015. RESULTS: A total of 600 patients with SBP (n = 408) or BA (n = 192) were enrolled. Patients with BA appeared to have a less severe clinical manifestation and lower mortality rate than patients with SBP. Gram-negative bacteria formed the majority of pathogens in SBP (73.9%) and BA (55.8%) cases. Higher ascitic fluid polymorphonuclear leucocytes (PMN) count and hepatocellular carcinoma were independent risk factors for BA episode progressing to SBP. The concentration of blood urea nitrogen (BUN) was independent risk factor for 30-day mortality of BA patients. For patients with SBP, the independent risk factors for 30-day mortality were age, Model for End-Stage Liver Disease (MELD) score, septic shock and hepatocellular carcinoma. Patients with third-generation cephalosporin or carbapenems resistant infection had a significantly lower survival probability. There were significant differences in clinical characteristics and outcome among the major bacteria. Multivariate analysis showed that patients infected with Klebsiella spp. had higher hazard ratio of 30-day mortality. CONCLUSION: Our study reported the bacteriological and clinical characteristics of patients with SBP and BA. Higher ascitic fluid PMN count and hepatocellular carcinoma were found to be independent risk factors for BA episode progressed to SBP. Outcome of ascitic fluid infection in patients with cirrhosis was influenced by the type of bacteria and antimicrobial susceptibility.

Microbiological characterisation of Klebsiella pneumoniae isolates causing bloodstream infections from five tertiary hospitals in Beijing, China.

OBJECTIVES: Klebsiella pneumoniae is prevalent in China. Little is known about the microbiological characteristics of clinical K. pneumoniae isolates causing bloodstream infections (BSIs). METHODS: BSI-causing K. pneumoniae (BSI-Kpn) were collected from five tertiary-care hospitals in Beijing. Genetic relatedness was analysed by PFGE, antimicrobial susceptibility was determined by agar dilution, and sequence types (STs) were evaluated by MLST. Hypermucoviscosity (HV) phenotype was identified by positive string test. Carbapenemase, capsular serotype and HV-associated genes were detected by PCR. RESULTS: A total of 219 non-duplicate BSI-Kpn were collected from December 2013 to December 2014 and were categorised into 203 types (strains) with unique PFGE patterns. Among 203 BSI-Kpn, 105 STs were identified. Overall, ST11 and ST23 were the predominant clones (14 strains each; 6.9%), followed by ST412 (n=13), ST37 (n=9), ST65 (n=7), ST15 (n=6), ST86 (n=6), ST592 (n=5) and ST29 (n=4). There were 74 STs containing only a single strain. Approximately 8.4% (17/203) of the strains exhibited carbapenem resistance, most producing KPC carbapenemase. The majority (75.9%; 154/203) of isolates were associated with non-K1/K2/K5/K20/K54/K57 serotypes. Only 16.3% (33/203) of the strains had K1/K2 serotypes. A total of 66 (32.5%) of the BSI-Kpn strains exhibited a HV phenotype. rmpA was a predominant factor in determining a HV phenotype. CONCLUSIONS: The majority of BSI-Kpn strains exhibited high genetic diversity and low resistance to commonly used antimicrobials. The specific capsular serotype and HV phenotype were not major features of BSI-Kpn strains in China.

Bacterial distributions and prognosis of bloodstream infections in patients with liver cirrhosis.

Bloodstream infections (BSIs) are a frequently observed complication in liver cirrhosis patients. This study aimed to investigate the microbiological characteristics and outcomes of BSIs in patients with liver cirrhosis. We retrospectively studied 852 patients with liver cirrhosis who developed a BSI. Patient outcome was evaluated using 30-day mortality and assessed using multivariate stepwise logistic regression analysis. Antibiotic sensitivity of the pathogens was tested. Gram-negative bacteria were responsible for 59.6% of BSIs, and Gram-positive bacteria caused 40.4% of the episodes among liver cirrhosis patients. The bacterial distribution significantly differed between hospital-acquired and community-acquired infections, especially in cases caused by Gram-negative pathogens. The results of the drug sensitivity test suggested that amikacin, cefoperazone/sulbactam, and piperacillin/tazobactam highly suppressed Gram-negative infections, while vancomycin and teicoplanin strongly inhibited Gram-positive BSIs. Liver failure, liver cancer, complications, Child-Pugh grade, septic shock, administration of appropriate antibiotics within 24 h, ICU admission, nosocomial infection, and Gram nature of the bacteria were independent risk factors for 30-day mortality (P < 0.05). The choice of initial empirical antibiotics should be based on the type, severity and origin of infection and on the local epidemiological data on antibiotic resistance. Accurate evaluation of risk factors for mortality may improve appropriate therapeutic choice.

Periploca forrestii saponin ameliorates CIA via suppressing proinflammatory cytokines and nuclear factor kappa-B pathways.

OBJECTIVE: Periploca forrestii Schltr has been used as a Chinese folk medicine for the treatment of rheumatism, arthralgia and fractures. However, the anti-arthritic activity of Periploca forrestii saponin (PFS) and the active compound has still not been revealed. This study aimed to investigate the protective effects and mechanisms of PFS on collagen type II (CII) collagen-induced arthritis (CIA) mice. We sought to investigate whether PFS and Periplocin could regulate osteoclastogenesis, and if so, further investigation on its mechanism of action. METHODS: Arthritis was induced in female BALB/c mice by CIA method. PFS was administered at a dose of 50 mg/kg body weight once daily for five weeks. The effects of treatment in mice were assessed by histological and biochemical evaluation in sera and paws. Anti-osteoclastogenic action of PFS and Periplocin was identified using an osteoclast formation model induced by RANKL. RESULTS: PFS ameliorated paw erythema and swelling, inhibited bone erosion in ankle joint histopathological examination. PFS treatment resulted in decreased IgG2a, and increased IgG1 levels in the serum of CIA mice. Decreased TNF-α, and increased interleukin (IL)-4 and IL-22 levels were also found in PFS-treated mice. PFS inhibited the I-κBα phosphorylation, blocked nuclear factor (NF)-κB/p65 phosphorylation and abrogated AP-1/c-Fos activity. PFS downregulated toll-like receptor (TLR) 4, STAT3 and MMP-9 expression in CIA mice and RANKL-induced osteoclastogenesis. PFS and Periplocin inhibited RANKL-induced osteoclast formation in a dose dependent manner within nongrowth inhibitory concentration, and PFS decreased osteoclastogenesis-related marker expression, including cathepsin K and MMP-9. CONCLUSION: This study revealed that the protective mechanism of PFS on CIA was associated with regulatory effects on proinflammatory factors and further on the crosstalk between NF-κB and c-Fos/AP-1 in vivo and in vitro. Therefore, PFS is a promising therapeutic alternative for the treatment of RA, evidencing the need to conduct further studies that can identify their active components in treating and preventing RA.

Molecular epidemiology of bla OXA-23 -producing carbapenem-resistant Acinetobacter baumannii in a single institution over a 65-month period in north China.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii poses a significant threat to hospitalized patients, as few therapeutic options remain. Thus, we investigated the molecular epidemiology and mechanism of resistance of carbapenem-resistant A.baumannii isolates in Beijing, China. METHODS: Carbapenem-resistant A.baumannii isolates (n = 101) obtained between June 2009 and November 2014 were used. Multilocus sequence typing (MLST) and PCR assays for class C and D ß-lactamase were performed on all isolates. S1 nuclease pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization were performed to identify the resistance gene location. RESULTS: All 101 A.baumannii isolates were highly resistant to frequently used antimicrobials, and were considered multidrug resistant. A total of 12 sequence types (STs) were identified, including 10 reported STs and 2 novel STs. Eighty-seven isolates were classified to clonal complex 92 (CC92), among which ST191 and ST195 were the most common STs. The bla OXA-23 gene was positive in most (n = 95) of the A.baumannii isolates. Using S1-nuclease digestion PFGE and Southern blot hybridization, 3 patterns of plasmids carrying bla OXA-23 were confirmed. ST191 and ST195 (both harboring bla OXA-23 ) caused outbreaks during the study period, and this is the first report of outbreaks caused by ST191 and ST195 in north China. CONCLUSION: bla OXA-23 -producing A.baumannii ST191 and ST 195 isolates can disseminate in a hospital and are potential nosocomial outbreak strains. Surveillance of imipenem-resistant A.baumannii and antimicrobial stewardship should be strengthened.

Low expression of CXCR1/2 on neutrophils predicts poor survival in patients with hepatitis B virus-related acute-on-chronic liver failure.

Polymorphonuclear neutrophils (PMNs) and proinflammatory cytokines have been implicated in the pathogenesis of acute-on-chronic liver failure (ACLF). But the utility of CXC chemokine receptor expression on PMNs as a biomarker for prediction of disease severity is still uncertain. In this study, we investigated the dynamic expression of CXCR1 and CXCR2 on neutrophils, and found that patients with hepatitis B virus-related ACLF displayed low expression of CXCR1 and CXCR2 on peripheral neutrophils compared with healthy subjects and patients with chronic hepatitis B. This expression pattern was correlated with disease severity. Additionally, increased production of IL-8 in peripheral blood was significantly associated with reduced CXCR1 and CXCR2 expression, as shown by the decreased CXCR1 and CXCR2 expression on neutrophils after treating neutrophils with plasma from ACLF patients. This effect could be overcomed through IL-8 blockage with an anti-IL-8 antibody. We also found that IL-8 production and neutrophil infiltration were coordinately increased in the liver tissue of HBV-ACLF patients, and this increase was associated with liver inflammation. Overall, increased production of IL-8 associated with neutrophils infiltration into the liver and decreased CXCR1/2 expression on peripheral neutrophils. CXCR1 and CXCR2 expression levels could be served as early markers to predict the severity of ACLF.