Lipopolysaccharide (LPS), the important component of the outer membrane of Gram-negative bacteria, contributes to the integrity of the outer membrane, and protects the cell against bactericidal agents. LPS, also called endotoxin synonymously, is well known as a potent inducer of the innate immune system that often causes septic shock in the intensive cares. Chemically, the amphiphilic LPS is made up of three parts, i.e., hydrophobic lipid A, hydrophilic core oligosaccharide chain, and hydrophilic O-antigenic polysaccharide side chain. Specially, the lipid A is known to be responsible for a variety of biological effects during Gram-negative sepsis. LPS can elicit a strong response from innate immune system and result in local or systemic adverse reactions. LPS can trigger massive inflammatory responses and may result in immunopathology, for which the molecular basis is mediated by the signal path- way of LPS. In recent years, a tremendous progress has been made in determining the associated proteins and receptors in the LPS signaling that leads to the disease. This review gives a summary of recent progresses of research on LPS and LPS receptors.
Anti-Bacterial Agents ; chemistry ; Drug Design ; Gram-Negative Bacteria ; drug effects ; Lipopolysaccharides ; chemistry

OBJECTIVETo investigate the epidemiological features of the pathogens responsible for prostatitis in the Changshu area, and offer some evidence for the clinical treatment of prostatitis.

METHODSThis study included 2 306 cases of prostatitis that were all clinically confirmed and subjected to pathogenic examinations in 3 hospitals of Changshu area from 2008 to 2012. Neisseria gonorrhoeae, mycoplasma urealyticum and chlamydia trachomatis were detected by nucleic acid amplification ABI 7500, the bacterial data analyzed by VITEK-2 Compact, the drug-resistance to antibacterial agents determined using the WHONET 5.6 software, and the enumeration data processed by chi-square test and curvilinear regression analysis using SPSS 19.0.

RESULTSThe main pathogens responsible for prostatitis were found to be Staphylococcus haemolyticus (30%), Staphylococcus epidermidis (12%), Enterococcus faecalis (9%), Escherichia coli (6%), Staphylococcus warneri and Staphylococcus aureus (3%), Mycoplasma urealyticum (8%), chlamydia trachomatis (5%) and Neisseria gonorrhoeae (6%). Statistically significant increases were observed in the detection rates of Escherichia coli (chi2 = 17.56, P<0.05), Mycoplasma urealyticum (chi2 = 8.73, P<0.05), Chlamydia trachomatis (chi2 = 8.73, P<0.05) and Enterococcus (chi2 = 8.22, P<0.05), but not in other pathogens. The resistance rates of Gram-positive bacteria to erythromycin and benzylpenicillin G were both above 45%, but with no significant difference between the two, those of Oxacillin (chi2 = 10.06, P<0.05) and Cefoxitin (chi2 = 9.89, P<0.05) were markedly increased, but those of quinolones, gentamycin and clindamycin remained low, except rifampicin (chi2 = 11.09, P<0.05). The resistance rates of Gram-negative bacteria to cefazolin and ampicillin were relatively high (mean 57.3%), and those to ceftriaxone (chi2 = 11.26, P<0.05) and trimethoprim sulfamethoxazole (chi2 =11.00, P< 0.05) significantly high; those to amikacin, cefepime, piperacillin/tazobactam and imipenem remained at low levels with no significant changes. However, the resistance rates of mycoplasma urealyticum to ciprofloxacin (chi2 = 11.18, P<0.05) and azithromycin (chi2 = 9.89, P<0.05) were remarkably increased.

CONCLUSIONGram-positive bacteria are the major pathogens responsible for prostatitis, but Escherichia coli, enterococcus and sexually transmitted disease pathogens are found to be involved in recent years. Quinolones and aminoglycosides are generally accepted as the main agents for the treatment of Gram-positive bacterial infection. However, rational medication for prostatitis should be based on the results of pathogen isolation and drug sensitivity tests in a specific area.

Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Bacterial ; Gram-Negative Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; Humans ; Male ; Prostatitis ; epidemiology ; microbiology

OBJECTIVE: To study the distribution and drug sensitivity test of bacteria of patients on chronic rhinosinusitis with or without nasal polyps. METHOD: The purulent discharges were collected from sinus of 175 patients with chronic rhinosinusitis with or without nasal polyps during endoscopic sinus surgery. The results of germiculture and drug sensitivity test were analyzed. RESULT: From 175 specimens, 118 (67%) showed positive results in germiculture. Among them, 79 strains of gram positive bacteria and 39 strains of gram negative bacteria were detected. Staphylococcus epidermidis, Staphylococcus aureus and Staphylococcus haemolyticus were the most common pathogens in gram positive bacteria. The most common pathogens of gram negative bacteria were P. Aeruginosa, Enterobacter aerogenes, Enterobacter cloacae. The sensitive antibiotic on gram positive bacteria were amikacin, Daptomycin, Linezolid, vancomycin, teicoplanin, amoxicillin and clavulanate potassium, cefuroxime, respectively. The sensitive antibiotics on Gram negative bacteria were amikacin, Cefoperazone/sulbactam and imipenem, ceftazidime ceftazidime, aztreonam, levofloxacin, respectively. CONCLUSION Bacterial infection was common happened in the sinus cavity of patients with chronic rhinosinusitis with or without nasal polyps. Gram positive bacteria were the main pathogenic bacteria and gram positive bacteria and gram negative bacteria have great differences in the sensitivity of antibiotics. For patients with chronic rhinosinusitis, the using of antibiotics should depend on the drug sensitivity test.
Bacterial Infections ; complications ; drug therapy ; Gram-Negative Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; Humans ; Microbial Sensitivity Tests ; Nasal Polyps ; microbiology ; Rhinitis ; microbiology ; Sinusitis ; microbiology

To explore new agents of quinolone derivatives with high antibacterial activity, 7-(4-alkoxyimino-3-methyl-3-methylaminopiperidin-1-yl)quinolones were designed and synthesized, and their activity against gram-positive and gram-negative strains was tested in vitro. Sixteen target compounds were obtained. Their structures were established by 1H NMR, HRMS and X-ray crystallographic analysis. Compounds 14k and 14m-14o show good antibacterial activity against the tested five gram-positive strains and five gram-negative strains (MIC: 0.25-16 micromg x mL(-1)), of which the most active compound 14o is 8-fold more potent than levofloxacin against S. pneumoniae (MIC: 4 microg x mL(-1)), and comparable to levofloxacin against S. aureus, S. epidermidis, E. faecalis and E. coli (MIC: 0.25-1 microg x mL(-1)), but generally less potent than gemifloxacin.
Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Gram-Negative Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; Molecular Structure ; Quinolones ; chemical synthesis ; chemistry ; pharmacology

BACKGROUNDPrevious researches about necrotic pancreatic tissue infections are numerous, but the study on systemic infection related to the severe acute pancreatitis (SAP) treatment period is limited. This study aimed to investigate the distribution and drug resistance of pathogenic bacteria in patients who had hepatobiliary surgery for SAP during the past three years.

METHODSA retrospective study was conducted on the distribution, category and drug resistance of pathogenic bacteria in patients who had hepatobiliary surgery for SAP from 2008 to 2011.

RESULTSA total of 594 pathogenic bacteria samples were isolated. Among them 418 isolates (70.4%) were Gram bacteria negative, 142 isolates (23.9%) were Gram bacteria positive, and 34 isolates (5.7%) were found fungi. The most common Gram negative bacteria were Escherichia coli (19.8%), and the dominant Gram positive pathogenic bacteria were Enterococcus faecium. The distribution of SAP-related infectious pathogens was mainly in peritoneal drainage fluid, sputum, bile, and wound secretions. Almost all the Gram negative pathogenic bacteria were sensitive to carbapenum. Extended-spectrum β-lactamases (ESBLs) producing strains were more resistant to penicillins and cephalosprins than the ESBLs non-producing strains. Staphylococcus was sensitive to vancomycin and linezolid. The drug resistance of meticillin-resistant staphylococcus (MRS) to commonly used antibiotics was higher than meticillin-sensitive streptococcus (MSS). Enterococcus sp. exhibited lower drug-resistance rates to vancomycin and linezolid.

CONCLUSIONSGram negative bacteria were the dominant SAP-related infection after hepatobiliary surgery. A high number of fungal infections were reported. Drug resistant rates were high. Rational use of antibiotics according to the site of infection, bacterial species and drug sensitivity, correctly executing the course of treatment and enhancing hand washing will contribute to therapy and prevention of SAP-related infection and decrease its mortality.

Anti-Bacterial Agents ; pharmacology ; Gram-Negative Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; pathogenicity ; Humans ; Microbial Sensitivity Tests ; Pancreatitis ; microbiology

BACKGROUNDThe Study for Monitoring Antimicrobial Resistance Trends program monitors the activity of antibiotics against aerobic and facultative Gram-negative bacilli (GNBs) from intra-abdominal infections (IAIs) in patients worldwide.

METHODSIn 2011, 1 929 aerobic and facultative GNBs from 21 hospitals in 16 cities in China were collected. All isolates were tested using a panel of 12 antimicrobial agents, and susceptibility was determined following the Clinical Laboratory Standards Institute guidelines.

RESULTSAmong the Gram-negative pathogens causing IAIs, Escherichia coli (47.3%) was the most commonly isolated, followed by Klebsiella pneumoniae (17.2%), Pseudomonas aeruginosa (10.1%), and Acinetobacter baumannii (8.3%). Enterobacteriaceae comprised 78.8% (1521/1929) of the total isolates. Among the antimicrobial agents tested, ertapenem and imipenem were the most active agents against Enterobacteriaceae, with susceptibility rates of 95.1% and 94.4%, followed by amikacin (93.9%) and piperacillin/tazobactam (87.7%). Susceptibility rates of ceftriaxone, cefotaxime, ceftazidime, and cefepime against Enterobacteriaceae were 38.3%, 38.3%, 61.1%, and 50.8%, respectively. The leastactive agent against Enterobacteriaceae was ampicillin/sulbactam (25.9%). The extended-spectrum β-lactamase (ESBL) rates among E. coli, K. pneumoniae, Klebsiella oxytoca, and Proteus mirabilis were 68.8%, 38.1%, 41.2%, and 57.7%, respectively.

CONCLUSIONSEnterobacteriaceae were the major pathogens causing IAIs, and the most active agents against the study isolates (including those producing ESBLs) were ertapenem, imipenem, and amikacin. Including the carbapenems, most agents exhibited reduced susceptibility against ESBL-positive and multidrug-resistant isolates.

Anti-Bacterial Agents ; pharmacology ; China ; Enterobacteriaceae ; classification ; drug effects ; genetics ; pathogenicity ; Gram-Negative Bacteria ; classification ; genetics ; Gram-Negative Bacterial Infections ; microbiology ; Humans ; Intraabdominal Infections ; microbiology ; Microbial Sensitivity Tests

A major barrier to the use of antimicrobial peptides as antibiotics is the toxicity or ability to lyse eukaryotic cells. In this study, a 26-residue amphipathic α-helical antimicrobial peptide A12L/A20L (Ac-KWKSFLKTFKSLKKTVLHTLLKAISS-amide) was used as the framework to design a series of D- and L-diastereomeric peptides and study the relationships of helicity and biological activities of α-helical antimicrobial peptides. Peptide helicity was measured by circular dichroism spectroscopy and demonstrated to correlate with the hydrophobicity of peptides and the numbers of D-amino acid substitutions. Therapeutic index was used to evaluate the selectivity of peptides against prokaryotic cells. By introducing D-amino acids to replace the original L-amino acids on the non-polar face or the polar face of the helix, the hemolytic activity of peptide analogs have been significantly reduced. Compared to the parent peptide, the therapeutic indices were improved of 44-fold and 22-fold against Gram-negative and Gram-positive bacteria, respectively. In addition, D- and L-diastereomeric peptides exhibited lower interaction with zwitterionic eukaryotic membrane and showed the significant membrane damaging effect to bacterial cells. Helicity was proved to play a crucial role on peptide specificity and biological activities. By simply replacing the hydrophobic or the hydrophilic amino acid residues on the non-polar or the polar face of these amphipathic derivatives of the parent peptide with D-amino acids, we demonstrated that this method could have excellent potential for the rational design of antimicrobial peptides with enhanced specificity.
Anti-Infective Agents ; chemistry ; pharmacology ; Circular Dichroism ; Drug Design ; Erythrocytes ; drug effects ; Gram-Negative Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; Hemolysis ; drug effects ; Humans ; Peptide Fragments ; chemistry ; pharmacology ; Protein Structure, Secondary ; Structure-Activity Relationship ; Substrate Specificity

OBJECTIVETo investigate the therapeutic effect and side effects of colistin in treating infections caused by multidrug-resistant (MDR) gram-negative bacillus in patients with severe burn in order to provide the basis for reasonable application of this antibiotic in clinic.

METHODSNine burn patients suffered from infections caused by MDR gram-negative bacillus admitted to our institute from August 2005 to January 2009 were involved in this study. On the premises that isolated bacteria were only sensitive to colistin or not sensitive to other antibiotics, patients were treated with intravenous drip of colistin (100 x 10(4) - 150 x 10(4) U/d), or intravenous drip combined with administration of the drug into respiratory tract by atomization or instillation (50 x 10(4) - 100 x 10(4) U/d). The bacteriologic and therapeutic effects and side effects (including neurotoxicity and nephrotoxicity, rise in serum levels of creatinine, urea nitrogen and cystatin C were detected and compared before and after administration) of colistin were observed.

RESULTSOut of 9 patients, 7 patients were with bloodstream and pulmonary infections, 1 patient was with bloodstream, pulmonary, and invasive wound infections, and 1 patient was with bloodstream and urinary tract infections. The pathogenic bacteria were proved to be Pseudomonas aeruginosa, Acinetobacter baumannii and Pseudomonas maltophilia. After the administration of colistin, bacteria clearance rate of blood reached 92.3% in 9 patients; isolation rate of MDR gram-negative bacillus of sputum was significantly decreased in 7 patients with pulmonary infection (before treatment 58.2% v.s. after treatment 14.6%, P < 0.01); a complete MDR gram-negative bacillus clearance of urine was observed in 1 patient with urinary tract infection. Colistin was clinically effective in 8 patients but ineffective in 1 patient (effective rate 88.9%). Compared with those before administration, serum levels of creatinine and urea nitrogen were decreased after administration in all patients; no significant difference in serum level of cystatin C among 8 patients was detected, except an obvious elevation in serum level of cystatin C in 1 patient after colistin therapy, and it lowered 1 month after discontinuation. No neurotoxicity or other side effect was observed during medication and 5 days after discontinuation in all patients.

CONCLUSIONSReasonable application of colistin is a good option for treating infections caused by MDR gram-negative bacillus in patients with severe burn, as no other more effective drug is found.

Adult ; Anti-Bacterial Agents ; adverse effects ; therapeutic use ; Burns ; drug therapy ; microbiology ; Colistin ; adverse effects ; therapeutic use ; Drug Resistance, Multiple, Bacterial ; Gram-Negative Bacteria ; drug effects ; Gram-Negative Bacterial Infections ; drug therapy ; Humans ; Male ; Middle Aged ; Treatment Outcome

AIMTo explore new agents of quinolone derivatives with high activity against Gram-positive organisms.

METHODSdl-7-(4,4-Dimethyl-3- aminomethylpyrrolidinyl)-quinolones were designed and synthesized, and their activity against Gram-positive organisms was tested in vitro.

RESULTSTen target compounds were obtained. The structures of these compounds were confirmed by 1H NMR, MS. The target compounds with dl-4,4-dimethyl-3-( methyl) aminomethylpyrrolidine side chains had high activity against Gram-positive organisms. Especially the MIC values of compound 22 for 4 strains of Gram-positive resistant bacteria (two strains of MRSA and two of MRSE) were 0.015 -0.5 mg x L(-), which exhibited more potent activities than gatifloxacin (4 - 128 times). Its MIC value for Pseudomonas aeruginosa 03-5 (0.008 mg x L(-1)) was 4 times as that of gatifloxacin (0.03 mg x L(-1)).

CONCLUSIONThe compound 22 showed high activity against Gram-positive organisms in vitro and it is worth of more investigation.

Anti-Bacterial Agents ; chemical synthesis ; pharmacology ; Gram-Negative Aerobic Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; Microbial Sensitivity Tests ; Molecular Structure ; Pseudomonas aeruginosa ; drug effects ; Quinolones ; chemical synthesis ; pharmacology ; Staphylococcus epidermidis ; drug effects

In order to find new cephalosporin with more and more potent antibacterial activity, nine new fourth-generation cephalosporins (N1-N9) were synthesized from ethyl 2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetate (1) via acylation, substitution, hydrolysis, active esterification, condensation and salt formation. The structures of compounds (N1-N9) were confirmed by IR, MS, 1H NMR and elemental analysis. The target compounds possess different antimicrobial activities against Gram-positive and Gram-negative bacteria. The preliminary results of antibacterial activities revealed that they showed better antibacterial activities against Gram-positive bacteria than cefpirome sulfate. In particular, their activities against Staphylococcus aureus and Streptococcus albus are better.
Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Cephalosporins ; chemical synthesis ; chemistry ; pharmacology ; Gram-Negative Bacteria ; drug effects ; Gram-Positive Bacteria ; drug effects ; Molecular Structure ; Staphylococcus aureus ; drug effects ; Streptomyces ; drug effects