Impact of Lycium barbarum polysaccharide on the expression of glucagon-like peptide 1 in vitro and in vivo.

Several studies showed the efficacy of Lycium barbarum polysaccharide (LBP) in diabetic animals and patients with type 2 diabetes mellitus (T2DM). However, the mechanism of LBP in alleviating T2DM based on glucagon-like peptide 1 (GLP1) has not been suitably elucidated. GLP1 is an important peptide that plays a role in blood glucose homeostasis. Inhibition of sodium/glucose cotransporter 1 (SGLT1) can result in a net increase in GLP1 release. We found that LBP could reduce SGLT1 expression. Thus, the effects of LBP on the first- and second-phase secretion of GLP1 were systematically assessed in vitro using STC1 cells and in vivo using diabetic KKAy mice. LBP could induce the first-phase secretion of GLP1 by stimulating calcium ion influx in vitro and by inhibiting alpha-glucosidase activity in vivo. Regulation of Gcg gene expression by modulating the Wnt/ß-catenin and cAMP/Epac pathways, as well as inhibition of alpha-glucosidase activity, was responsible for the second-phase secretion of GLP1. LBP could stimulate GLP1 secretion; however, dipeptidyl peptidase 4 (DPP4) activated by LBP might offset the second-phase secretion of GLP1. Thus, we suggest considering the simultaneous use of LBP and a DPP4 inhibitor to stimulate slow, continuous GLP1 secretion. Further studies are warranted for in-depth mechanistic information.

Integrated Metabolomics and Proteomics Analysis Reveals Plasma Lipid Metabolic Disturbance in Patients With Parkinson's Disease.

Parkinson's disease (PD) is a common neurodegenerative disease in the elderly with a pathogenesis that remains unclear. We aimed to explore its pathogenesis through plasma integrated metabolomics and proteomics analysis. The clinical data of consecutively recruited PD patients and healthy controls were assessed. Fasting plasma samples were obtained and analyzed using metabolomics and proteomics methods. After that, differentially expressed metabolites and proteins were identified for further bioinformatics analysis. No significant difference was found in the clinical data between these two groups. Eighty-three metabolites were differentially expressed in PD patients identified by metabolomics analysis. These metabolites were predominately lipid and lipid-like molecules (63%), among which 25% were sphingolipids. The sphingolipid metabolism pathway was enriched and tended to be activated in the following KEGG pathway analysis. According to the proteomics analysis, forty proteins were identified to be differentially expressed, seven of which were apolipoproteins. Furthermore, five of the six top ranking Gene Ontology terms from cellular components and eleven of the other fourteen Gene Ontology terms from biological processes were directly associated with lipid metabolism. In KEGG pathway analysis, the five enriched pathways were also significantly related with lipid metabolism (p < 0.05). Overall, Parkinson's disease is associated with plasma lipid metabolic disturbance, including an activated sphingolipid metabolism and decreased apolipoproteins.

In Vitro Antimicrobial Activity of Various Cefoperazone/Sulbactam Products.

: This study aims to assess the in vitro activity of different samples of cefoperazone/sulbactam (CFP/SUL) against multidrug-resistant organisms (MDROs). Clinical isolates of extended-spectrum ß-lactamase (ESBL)-Escherichia coli, ESBL-Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii (CR-AB), and carbapenem-resistant Pseudomonas aeruginosa (CR-PA) were collected. The minimum inhibitory concentration (MIC) and time-killing methods were used to assess and compare the in vitro activities of different samples of cefoperazone/sulbactam (CFP/SUL) against these MDROs. For ESBL-E. coli, ESBL-K. pneumoniae, and CR-PA, product C had smaller variations than product A and B (p < 0.05). For CR-AB, product B had the largest variation compared to the other two products (p < 0.05). In the time-killing studies, significant differences among the products when used at 16/16 µg/mL were noted for ESBL-E. coli, ESBL-K. pneumoniae, and CR-AB isolates. In conclusion, this study demonstrated the significantly different activity of different products of CFP/SUL against MDROs.

Colistin-sparing regimens against Klebsiella pneumoniae carbapenemase-producing K. pneumoniae isolates: Combination of tigecycline or doxycycline and gentamicin or amikacin.

BACKGROUND/PURPOSE: In vitro studies of the combination of an aminoglycoside with tigecycline or doxycycline against Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae isolates are rarely published. The goal of this study was to evaluate the antibacterial activity of the combination regimens. METHODS: Thirteen genetically different KPC-producing K. pneumoniae isolates were randomly selected. Drug concentrations of amikacin, gentamicin, tigecycline, and doxycycline were adjusted to 1-, 1/2-, and 1/4-fold of respective minimum inhibitory concentrations (MICs). Each drug alone or the combinations of amikacin or gentamicin with tigecycline or doxycycline were tested by combination studies. RESULTS: Treatment with the 1× MIC concentration in combinations of amikacin or gentamicin and tigecycline or doxycycline for 24 hours resulted in bactericidal activity of 84-100% in the isolates. Treatment with 1/2× MIC combinations resulted in synergism of 69-100% in the isolates. Notably, doxycycline plus gentamicin or amikacin was synergistic for all tested isolates. However, bactericidal or synergistic effect was barely evident following 1/4× MIC combinations. There was no antagonism in any of the combination regimens. CONCLUSION: Enhanced activity was noted following treatment with doxycycline combined with gentamicin or amikacin against KPC-producing K. pneumoniae isolates, warranting further in vitro and animal investigations before clinical application.

Simultaneous three Enterobacteriaceae with different bla NDM-1-encoding plasmids in a patient transferred from mainland China to Taiwan.

New-Delhi metallo-ß-lactamase1 (NDM-1) Enterobacteriaceae are increasing worldwide. Herein, we describe a single patient who carried three unusual NDM-1 carbapenem-resistant Enterobacteriaceae - Enterobacter cloacae (E. cloacae) yielded from a urine specimen and Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) from stool specimens. For E. cloacae, its bla NDM-1-encoding plasmid was pKP04NDM with a size of ~54 kb replicons with an IncN backbone. For K. pneumoniae, its bla NDM-1-encoding plasmid was pNDM-BTR with a size of ~59.6 kb and belonged to IncN. For E. coli, its main bla NDM-1-encoding plasmid was pIMP-HK1500, and the NDM-1 gene was obtained from a part of pNDM-BTR (8439 bp). These three clinical strains are reported for the first time and are assumed to be imported from mainland China to Taiwan. The three different plasmids were never reported in K. pneumoniae, E. coli, and Citrobacter spp before. Owing to their associated multidrug resistance, appropriate measures of periodic, targeted surveillance, and development of new antimicrobial agents are urgently needed.

In vitro and in vivo antibacterial activity of tigecycline against Vibrio vulnificus.

BACKGROUND/PURPOSE: The aim of this study is to investigate the role of tigecycline in Vibrio vulnificus infection. METHODS: Eight randomly selected clinical V. vulnificus isolates were studied to obtain the minimal inhibitory concentrations (MICs) of minocycline, cefotaxime, and tigecycline, and the time-kill curves of tigecycline alone or in combination with other drugs. A peritonitis mouse model was used for the evaluation of the therapeutic efficacy of tigecycline alone or cefotaxime in combination with minocycline or tigecycline. RESULTS: The MIC of minocycline, cefotaxime, and tigecycline for eight clinical V. vulnificus isolates was 0.06-0.12 µg/mL, 0.03-0.06 µg/mL, and 0.03-0.06 µg/mL, respectively. In time-killing studies, at the concentration of 1 × MIC, the inhibitory effect of tigecycline persisted for 24 hours in five of eight isolates. With 2 × MIC and trough level, the inhibitory effect was noted in all isolates for 24 hours. With the combination of minocycline plus cefotaxime and tigecycline plus cefotaxime at 1/2 × MIC, the bactericidal effect was noted in 25% and 62.5% of eight isolates and synergism in 50% and 75% of isolates. With a low (1.25 × 105 CFU/mL) inoculum, all infected mice survived with tigecycline alone, tigecycline plus cefotaxime, or minocycline plus cefotaxime on the 14th day. At the inoculum of 1.25 × 106 CFU, the survival rate was 33.3% on the 14th day in the tigecycline plus cefotaxime-treated group, but none of the mice treated by tigecycline alone or minocycline plus cefotaxime survived (33.3% vs. 0%, p = 0.01 by Fisher's exact test). CONCLUSION: Our in vitro combination and animal studies indicate that tigecycline could be an option for the treatment of invasive V. vulnificus infections.

Cephalosporin-Glycopeptide Combinations for Use against Clinical Methicillin-Resistant Staphylococcus aureus Isolates: Enhanced In vitro Antibacterial Activity.

The empirical combination of both a beta-lactam and glycopeptide to counter potential staphylococcal pathogens may improve the clinical outcomes for cases of Staphylococcus aureus bacteremia. We reported comparative in vitro studies of combination effects of different cephalosporins (i.e., cefazolin, cefmetazole, cefotaxime, and cefepime) combined with glycopeptides for 34 randomly selected methicillin-resistant S. aureus (MRSA) isolates by three methods, including the checkerboard, time-killing, and combination MIC measurement methods. Thirteen SCCmec type III isolates with a cefazolin MIC of ≥ 128 µg/mL were classified as the high-cefazolin MIC (HCM) group, whereas 13 SCCmec type IV and 8 SCCmec type V isolates were classified as the low-cefazolin MIC (LCM) group. With the checkerboard method, synergism was present for vancomycin-based combinations at 30.8-69.2 and 13.6-66.7%, as well as teicoplanin-based combinations of 38.5-84.6 and 0-47.6%, of the HCM and LCM isolates, respectively. No antagonism was noted. The in vitro inhibitory activity was evident even at a low concentration of 1/512x MIC of cephalosporin combined with sub-inhibitory concentrations (1/2x MIC) of a glycopeptide. With time-killing assays, synergism was noted at 1/2x or 1x susceptible breakpoint concentrations (SBCs) of a cephalosporin combined with 1/4 or 1/2 MIC of a glycopeptide. In the presence of 1/2 SBC of a cephalosporin, vancomycin or teicoplanin MICs decreased an average of 2.0- to 6.6- or 1.6- to 5.5-fold, respectively. With 8 µg/mL cephalosporin, the decline of glycopeptide MICs was most obvious in the presence of cefmetazole. In conclusion, cephalosporin-glycopeptide combinations at clinically achievable concentrations can exhibit in vitro synergistic antibacterial activity against clinical MRSA isolates. Such combinations require more clinical data to support their application for use in human MRSA infections.

Fenretinide inhibits macrophage inflammatory mediators and controls hypertension in spontaneously hypertensive rats via the peroxisome proliferator-activated receptor gamma pathway.

Fenretinide is a novel anticancer agent reported to exhibit anti-invasive and antimetastatic activities. It has also been shown to improve obesity and diabetes, although the effects of fenretinide on hypertension are still unknown, and the detailed mechanisms remain unclear. In this study, we have shown that treatment with lipopolysaccharide (LPS) decreased the expression of peroxisome proliferator-activated receptor γ (PPARγ) in RAW264.7 macrophages, and pretreatment with fenretinide reversed the effect of LPS on PPARγ expression. In addition, LPS-induced pro-inflammatory cytokine production, including tumor necrosis factor-α, interleukin 6, and monocyte chemoattractant protein 1 were dose-dependently reversed by fenretinide, and the effects of fenretinide on LPS-induced pro-inflammatory cytokine production were blocked by treatment with PPARγ antagonist. Moreover, fenretinide decreased LPS-induced inducible nitric oxide synthase expression and nitrogen oxide production. These effects were blocked by the pretreatment with PPARγ antagonist in a dose-dependent manner, indicating fenretinide activated PPARγ to exert anti-inflammation activity. In view of the role of inflammation in hypertension and the anti-inflammatory action of fenretinide, we found that administration of fenretinide in spontaneously hypertensive rats significantly decreased blood pressure. Taken together, these results indicate that fenretinide might be a potent antihypertensive agent that works by suppressing inflammation via activating PPARγ.

RNA polymerase B subunit gene mutations in biofilm-embedded methicillin-resistant Staphylococcus aureus following rifampin treatment.

BACKGROUND/PURPOSE: This study was conducted to compare the mutation rates of different rpoB sites and rifampin minimum inhibitory concentration (MIC) changes prior to and after rifampin therapy for biofilm-embedded methicillin-resistant Staphylococcus aureus (MRSA) isolates. METHODS: The screening of rifampin-resistant MRSA isolates, from the biofilm at Day 5 with or without exposure to the susceptible breakpoint concentration of rifampin recommended by the Clinical and Laboratory Standards Institute (1 mg/L), was conducted using agar plates containing rifampin. A partial fragment of RNA polymerase B subunit gene (rpoB), including clusters I and II, was amplified and sequenced. The rifampin MIC values and mutation frequencies at different sites of rpoB were measured and evaluated in rifampicin-resistant isolates. RESULTS: Rifampin-resistant mutants could be selected from all of 39 randomly selected rifampin-susceptible MRSA isolates in the biofilm model. The spontaneous mutation frequency ranged from 1.00 × 10(-4) to 3.85 × 10(-7). Mutation at codon 481 was most commonly found at 35 (89.7%) of 39 MRSA isolates. Without rifampin induction, the MIC ranged between 0.125 mg/L and1024 mg/L and mutation sites included cluster I 464, 466, 468, 471, 474, 477, 481, 484, 486 and cluster II 519, 527, 529 with the percentage of 471 (35.9%), 477 (33.3%), 481 (53.8%), and 484 (35.9%). Conversely, with the induction of rifampin, the MIC value ranged ∼256-1024 mg/L. The mutation sites that were more concentrated included 468 (17.9%), 477 (30.8%), 481 (89.7%), 484 (17.9%), and 486 (33.3%). CONCLUSION: We documented high rifampin resistance induction activity when MRSA was engaged in biofilm with rifampin exposure. Monotherapy seems to be inadequate for MRSA in biofilm. There is an urgent need for developing effective combination therapies with less rifampin resistance-inducing activities for treating MRSA in biofilms.

Prototheca algaemia: a rare but fatal opportunistic infection among immunocompromised individuals.

Infections due to Prototheca spp. are ubiquitous in nature, occurring in both immunocompetent and immunocompromised patients. The study cohort consisted of 14 cases of Prototheca algaemia reported over the past 5 decades and 2 recent cases from study hospitals. Prototheca wickerhamii was the most common species. The overall mortality rate was 62.5%. Prototheca algaemia, a healthcare-associated infection, was observed in immunocompromised patients and was associated with a poor prognosis.

In vitro efficacy of fosfomycin-based combinations against clinical vancomycin-resistant Enterococcus isolates.

Vancomycin-resistant (VR) enterococci (VRE) are increasingly important nosocomial pathogens, commonly causing catheter-related urinary tract infections or vascular catheter-related bloodstream infections. In this study, 10 Enterococcus faecium and 9 Enterococcus faecalis different pulsed-field gel electrophoresis genome-type VR clinical isolates were detected. The potential role of fosfomycin-based combination regimens for biofilm-related VRE infection is in vitro evaluated. Anti-VRE activities of fosfomycin, ampicillin, linezolid, minocycline, rifampicin, tigecycline, teicoplanin, vancomycin alone, or fosfomycin-based combinations were studied by time-kill method and a biofilm model. Of the fosfomycin-based combinations, a synergistic effect was particularly noted for teicoplanin against 89% of the VR E. faecalis isolates. In a biofilm model, only linezolid alone was able to reduce the bacterial loads, and the use of fosfomycin-based combinations, excluding rifampicin (40%), failed to enhance antibacterial activity against VR E. faecium. For E. faecalis, an inhibitory effect was evident using ampicillin alone or fosfomycin plus rifampicin (100%), tigecycline (56%), or teicoplanin (44%). However, an antagonistic effect was found for ampicillin plus fosfomycin against 2 of 3 of the VR E. faecalis isolates. The antibacterial activities of the drugs tested against VRE in vitro varied by species. Ampicillin exhibited potential activity against planktonic- and biofilm-embedded VR E. faecalis. Fosfomycin-based combinations may have enhanced antibacterial effects against VRE even in the biofilm model, and this observation warrants further clinical studies.

In vitro efficacies and resistance profiles of rifampin-based combination regimens for biofilm-embedded methicillin-resistant Staphylococcus aureus.

To compare the in vitro antibacterial efficacies and resistance profiles of rifampin-based combinations against methicillin-resistant Staphylococcus aureus (MRSA) in a biofilm model, the antibacterial activities of vancomycin, teicoplanin, daptomycin, minocycline, linezolid, fusidic acid, fosfomycin, and tigecycline alone or in combination with rifampin against biofilm-embedded MRSA were measured. The rifampin-resistant mutation frequencies were evaluated. Of the rifampin-based combinations, rifampin enhances the antibacterial activities of and even synergizes with fusidic acid, tigecycline, and, to a lesser extent, linezolid, fosfomycin, and minocycline against biofilm-embedded MRSA. Such combinations with weaker rifampin resistance induction activities may provide a therapeutic advantage in MRSA biofilm-related infections.

Use of Carbapenems against clinical, nontyphoid Salmonella isolates: results from in vitro and in vivo animal studies.

The emergence of multidrug-resistant Salmonella isolates has created the need for new therapeutic agents. We evaluated the intracellular activity of four carbapenem compounds against clinical nontyphoid Salmonella (NTS) isolates in vitro and ex vivo. Subsequently, the efficacy of carbapenem treatment against selected Salmonella isolates in vivo was assessed using a murine peritonitis model. The MIC(50) and MIC(90) for doripenem, ertapenem, imipenem, and meropenem against 126 NTS isolates were found to be 0.062 and 0.062, 0.015 and 0.015, 0.5 and 1, and 0.031 and 0.031 µg/ml, respectively. The intracellular killing effect of ertapenem was sustained for 24 h and was superior to that of imipenem, meropenem, and doripenem; its effect was comparable to that of ceftriaxone. Ertapenem demonstrated an excellent pharmacokinetic profile with a percent time above the MIC of 75.5% and an area under the concentration-time curve/MIC ratio of 20,733. When peritoneal exudate cells were examined directly ex vivo from mice with Salmonella-induced peritonitis, cells from mice treated with ertapenem and ceftriaxone had intracellular and extracellular bacterial counts reduced 10(2)- to 10(4)-fold and exhibited killing effects similar to each other. The survival rates of mice inoculated with 1 × 10(5) and 10(6) CFU of a ceftriaxone-susceptible Salmonella isolate that were subsequently treated with ertapenem or ceftriaxone were 100% and 90%, respectively. When mice were inoculated with 5 × 10(4) and 10(5) CFU of a ceftriaxone-resistant and ciprofloxacin-resistant Salmonella isolate, mice treated with ertapenem had a higher survival rate than mice treated with ceftriaxone (70% versus 0% and 50% versus 0%, respectively; P < 0.001). Our results suggest that ertapenem is at least as effective as ceftriaxone in treating murine Salmonella infections and show that further clinical investigations on the potential use of ertapenem in treatment of human Salmonella infections are warranted.

Brevundimonas vesicularis bacteremia resistant to trimethoprim-sulfamethoxazole and ceftazidime in a tertiary hospital in southern Taiwan.

BACKGROUND: Over the past 20 years, Brevundimonas vesicularis has rarely been reported as a pathogen causing human infection. The clinical manifestations of B. vesicularis bacteremia and its susceptibility to antibiotics has not been characterized. METHODS: A retrospective study was conducted between 2006 and 2009 in a tertiary-care hospital in southern Taiwan. RESULTS: A total of 22 cases of B. vesicularis bacteremia were identified during the study with 86% being community-acquired primary bloodstream infections. Of the 22 patients, 15 (68%) presented with fever, fewer comorbidities, shorter hospital stays, lower mean creatinine levels (1.10 mg/dL vs. 1.74 mg/dL), lower aspartate aminotransferase levels (29.1 IU/L vs. 79.0 IU/L), and lower alanine aminotransferase levels (16.4 IU/L vs. 67.0 IU/L) when compared to afebrile patients. Among the bacterial isolates, 90.9% were susceptible to cefpirome, imipenem and piperacillin/tazobactam while 86.4% were susceptible to gentamicin, amikacin and ciprofloxacin. However, 63.6% of the bacterial isolates were susceptible to ceftazidime, and only 59.1% were susceptible to trimethoprim-sulfamethoxazole (TMP-SMX). The 30-day mortality rate from all causes was 4.5%. CONCLUSION: B. vesicularis is able to cause community-acquired and low-mortality primary bloodstream infections. The resistance of B. vesicularis to trimethoprim-sulfamethoxazole and ceftazidime limits the choice of available antibiotics for treatment.