Biofilms are communities of surface-associated bacteria or fungi embedded in a self-produced extracellular polymeric matrix that are notoriously difficult to be eradicated and are sources of many recalcitrant infections. Treatment for biofilm infection with any individual drug is always less effective, while the combinations of different types of drugs are superior to monotherapy concerning the removing of biofilms. This paper focus on research progress in recent years for synergistic effect of drugs in combination against biofilms formed by Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Candida albicans.
Anti-Bacterial Agents ; pharmacology ; Antifungal Agents ; pharmacology ; Bacteria ; drug effects ; Biofilms ; drug effects ; growth & development ; Candida albicans ; drug effects ; Escherichia coli ; drug effects ; Pseudomonas aeruginosa ; drug effects ; Staphylococcus aureus ; drug effects ; Staphylococcus epidermidis ; drug effects

OBJECTIVETo provide a new therapeutic approach for Staphylococcus epidermidis biofilm-associated infections by the study of inhibitory effect of andrographolide (AG) on S. epidermidis biofilm.

METHODS. epidermidis biofilms were set up in vitro, erythromycin was acted as the positive control agent, XTT reduction assay was used to evaluate AG on the initial adhesion of S. epidermidis and bacterial metabolism within biofilm, microscope was applied to observe biofilm morphology, and Congo red assay was used to detect polysacchatide interc-ellular adhesion (PIA)formation when exposed to AG.

RESULTAG showed inhibitory effects against the initial adhesion of S. epidermidis at concentrations of 1 000,100, 10 mg x L(-1), respectively,and inhibited metabolism of biofilm bacteria at the concentration of 31.25 mg x L(-1), and exhibited significantly inhibition against the biofilm morphology at the concentration of 250 mg x L(-1), while did not display inhibition against PIA formation at the concentration of 10 mg x L(-1).

CONCLUSIONAG could remarkably inhibit biofilm formation of S. epidermidis, although it was less potent than erythromycin.

Bacterial Adhesion ; drug effects ; Biofilms ; drug effects ; Diterpenes ; pharmacology ; Dose-Response Relationship, Drug ; Erythromycin ; pharmacology ; Staphylococcus epidermidis ; drug effects ; physiology

AIMTo investigate the mechanism of the interaction between montmorillonite and bacteria by studying the reactions of different charges of montmorillonites with bacteria.

METHODSBacteriostatic test: one loop of E. coli and Staphylococcus aureus at the concentration of 1 x 10(6).mL-1 was incubated to the plate culture medium containing different concentrations of montmorillonite, and incubated 24 h to observe the growth of bacteria. Bacterial adsorptive test: different amounts of montmorillonite were added into the artificially simulated intestinal solution (containing bacteria 1 x 10(7).mL-1). After the culture, the bacterial colonies were counted.

RESULTSThe results showed that montmorillonite per se showed no bacteriostatic or bactericidal effect, but after exchange with metal ion and functional groups which inhibits bacteria, then it showed these activities. Adsorption was the main way between montmorillonite and bacteria. The special way of fixing bacteria into the "carriage" of montmorillonite gel which carry this structure was its pharmacological basis of curing diarrhea. The adsorption effect was related to layer charge density of the montmorillonites.

CONCLUSIONMontmorillonite showed adsorption ability of bacteria with minus related to its layer charge, but has no bacteriostatic and bactericidal effect.

Adsorption ; Anti-Ulcer Agents ; pharmacology ; Bentonite ; pharmacology ; Escherichia coli ; drug effects ; Staphylococcus aureus ; drug effects

OBJECTIVETo prepare and evaluate novel chlorine dioxide-based disinfectant powder in single-pack that is more convenient for use and transportation.

METHODSOrthogonal experiment was performed to determine the recipe of the disinfectant powder. Stability test, suspension quantitative bactericidal test, simulation field trial, and animal toxicity test were carried out to observe its bactericidal and toxicological effects.

RESULTSThe orthogonal experiment showed that the type of water solution had no effect on the disinfectant powder and the best ratio of sodium chlorite to solid acid was 1:3. Ten grams of the disinfectant powder was fully dissolved in 20 mL water for 2 min, and diluted to 500 mL in water. After 5-10 min, the concentration of chlorine dioxide (ClO2) solution was 266 mg/L to 276 mg/L. After stored at 54 degrees C for 14 d, the average concentration of ClO2 was decreased by 5.03%. Suspension quantitative bactericidal test showed that the average killing logarithm (KL) value for both Staphylococcus aureus and Escherichia coli in 100 mg/L ClO2 solution for 2 min was over 5.00. in simulation field trial, the average descending KL value for Escherichia coli in the solution containing 100 mg/L ClO2 for 5 min was over 3.00. The mouse acute LD50 in the solution 5 times exceeded 5000 mg/kg. The disinfectant powder was not toxic and irritative to rabbit skin and had no mutagenic effect on mouse marrow polychromatic erythrocytes (PCE).

CONCLUSIONThe stability and bactericidal efficacy of solid chlorine dioxide-based disinfectant powder in single-pack are good. The solution containing 100 mg/L ClO2 can kill vegetative forms of bacteria. The concentration of ClO2 on the disinfecting surface of objects is 100 mg/L. The disinfectant powder is not toxic and irritative.

Chlorine Compounds ; pharmacology ; Disinfectants ; pharmacology ; Escherichia coli ; drug effects ; Oxides ; pharmacology ; Staphylococcus aureus ; drug effects

OBJECTIVETo study the differences of theantimicrobial-resistant profiles between the isolates of Staphylococci aureu from children and from adults.

METHODSStaphylococci was identified by the plasma coagulase test, Staphylococci monoclonal antibody and VITEK-32 fully automated microbiology analyzer.Antimicrobial susceptibility testing was done by the K-B disk diffusion for 84 Staphylococci isolates from children and 74 Staphylococci isolates from adults. Cefoxitin was used for detecting methillicin-resistant Staphylococcus aureus (MRSA) by the disk diffusion test.

RESULTSSeven (8%) MRSA isolates were found in Staphylococci isolates from children compared with 35 MRSA isolates (47%) in those from adults (p<0.01). All strains were susceptible to vancomycin. All strains from children were susceptible to fusidic acid. The resistant rates of the isolates from children to cefazolin, cefuroxime, gentamicin, cefoxitin, and levofloxacin were significantly lower than those from adults (p<0.01).

CONCLUSIONSThe antimicrobial resistance of the Staphylococcus aureus isolates from adults is more prevalent than that in the isolates from children.

Adult ; Child ; Drug Resistance, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus ; isolation & purification ; Microbial Sensitivity Tests ; Staphylococcus aureus ; drug effects

The emergence of multi-drug resistant gram-positive cocci such as methicillin-resistant (MR) staphylococci, vancomycin-resistant (VR) enterococci, and vancomycin-intermediate resistant S. aureus (VISA) has given new urgency to the development of new antimicrobial agents. One of these is quinupristin/dalfopristin (Q/D). We decided to determine the susceptibility of gram-positive cocci isolated at two university hospitals in Seoul to Q/D and compare the results with eight other antimicrobial agents. We investigated 120 isolates of S. aureus including 49 MRSAs and one VISA, 120 isolates of coagulase negative staphylococci (CNS), 64 E. faecalis and 56 E. faecium, including seven strains of VR E. faecium. Minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) for several antimicrobials, including vancomycin and Q/D, were determined by broth microdilution. All S. aureus including VISA were susceptible to Q/D. Q/D MIC90 for both methicillin-susceptible S. aureus (MSSA) and MRSA was 0.25 g/mL. 49 (87.5%) of 56 E. faecium including six of seven VR E. faecium were susceptible to Q/D. E. faecalis were not susceptible to Q/D (only 1.5% susceptible), but were inhibited by ampicillin (94% susceptible) or vancomycin (95%). CNS was susceptible to Q/D (96% susceptible) and vancomycin (100% susceptible). One of 38 staphylococci and two of 17 E. faecium were tolerant to Q/D. In conclusion, Q/D showed excellent activity against all species of gram-positive cocci including MRSA, VISA, and VR E. faecium except E. faecalis, and may provide a valuable option for the treatment of infections caused by these emerging nosocomial pathogens of gram-positive cocci.
Antibiotics/pharmacology* ; Antibiotics, Peptide/pharmacology* ; Coagulase/analysis ; Enterococcus faecalis/drug effects ; Enterococcus faecium/drug effects ; Human ; Korea ; Microbial Sensitivity Tests* ; Staphylococcus/enzymology ; Staphylococcus/drug effects ; Staphylococcus aureus/drug effects ; Support, Non-U.S. Gov'tn ; Virginiamycin/pharmacology* ; Virginiamycin/analogs & derivatives*

OBJECTIVETo analyze the change in drug resistance of Staphylococcus aureus (SAU) in the PLA general hospital from January 2008 to December 2012, and to provide solid evidence to support the rational use of antibiotics for clinical applications.

METHODSThe SAU strains isolated from clinical samples in the hospital were collected and subjected to the Kirby-Bauer disk diffusion test. The results were assessed based on the 2002 American National Committee for Clinical Laboratory Standards (NCCLS) guidelines.

RESULTSSAU strains were mainly isolated from sputum, urine, blood and wound excreta and distributed in penology, neurology wards, orthopedics and surgery ICU wards. Except for glycopeptide drugs, methicillin-resistant Staphylococcus aureus (MRSA) had a higher drug resistance rate than those of the other drugs and had significantly more resistance than methicillin-sensitive Staphylococcus aureus (MSSA) (P < 0.05). In the dynamic observation of drug resistance, we discovered a gradual increase in drug resistance to fourteen test drugs during the last five years.

CONCLUSIONDrug resistance rate of SAU stayed at a higher level over the last five years; moreover, the detection ratio of MRSA keeps rising year by year. It is crucial for physicians to use antibiotics rationally and monitor the change in drug resistance in a dynamic way.

Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Multiple, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; Staphylococcal Infections ; drug therapy ; Staphylococcus aureus ; drug effects

Staphylococcus aureus and Staphylococcus epidermidis strains isolated at eight large medical centers in Korea were examined for methicillin resistance and resistance to eight other antibiotics; cefazolin, cefamandole, cefuroxime, cefoxitin, cefotaxime, moxalactam, penicillin G and vancomycin. Methicillin resistance was found in 296 of 1225 strains (24.2%) of S. aureus and 126 of 348 strains (36.2%) of S. epidermidis. Methicillinresistant strains were isolated from all sources with the frequency of isolation ranging from 11% to 60%. From pleural effusion, throat swab and blood, methicillin-resistant strains of S. aureus were more frequently isolated with statistical significance (Chi-squared test, 95% confidence). Almost all of Methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE) strains were multiply resistant to one or more tested eight antibiotics. However only 7(2.4%) of 296 MRSA strains and 2(1.6%) of 126 MRSE strains were resistant to vancomycin. Vancomycin was the most effective antibiotic against staphylococcal isolates as well as MRSA and MRSE.
Anti-Bacterial Agents/*pharmacology ; Cross Infection/microbiology ; Drug Resistance, Microbial ; Humans ; Korea ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/isolation & purification ; Staphylococcus epidermidis/*drug effects/isolation & purification

OBJECTIVETo discuss the possible mechanism of drug resistance transmission between Staphylococcus and Escherichia coli.

METHODSThe chloramphenicol resistance plasmid of Staphylococcus aureus was extracted to transform the sensitive Escherichia coli, and the drug-resistant Escherichia coli were screened by drug sensitivity test.

RESULTSThe drug-resistant Escherichia coli were successfully obtained.

CONCLUSIONStaphylococcus may have a natural shuttle plasmid of drug resistance, which can transform Escherichia coli under specific conditions.

Drug Resistance, Bacterial ; genetics ; Escherichia coli ; drug effects ; genetics ; Plasmids ; Staphylococcus ; genetics ; Transformation, Bacterial

OBJECTIVETo study the distribution and drug resistance of methicillin resistant Staphylococcus strains in various specimens of inpatients in burn wards, and to provide reference for clinical treatment.

METHODSBacteria were isolated from specimens of wound exudate, blood, sputum, and bronchoalveolar lavage fluid etc., which were collected from patients hospitalized in our burn wards from January 2008 to December 2010. The bacteria were routinely cultured and identified. Drug resistance of the Staphylococci to 15 antibiotics commonly used in clinic was identified by K-B disk diffusion method. Data were processed with statistical software WHONET 5.5. The homology of 40 strains of methicillin resistant Staphylococcus aureus (MRSA) was analyzed by pulsed-field gel electrophoresis (PFGE).

RESULTSAltogether 386 strains of Staphylococcus were isolated, including 196 strains of Staphylococcus aureus and 190 strains of coagulase negative Staphylococcus. The mean annual isolation rates of MRSA and methicillin resistant coagulase negative Staphylococcus (MRCoNS) were respectively 73.00% (143/196) and 74.20% (141/190). The resistance rates of MRSA and MRCoNS to β-lactams drugs, such as penicillin, oxacillin, cefazolin, and cefuroxime were 100.00% in every year. No Staphylococcus strains resistant to vancomycin, teicoplanin, or linezolid were found. Three different PFGE patterns A, B, and C were identified among 40 MRSA strains, including 33 strains of type A (30 strains in sub-type A1 and 3 strains in sub-type A2), 6 strains of type B (respectively 3 strains in sub-types B1 and B2), and 1 strain of type C.

CONCLUSIONSThe isolation rates of MRSA and MRCoNS were high in our burn wards from January 2008 to December 2010. All of them showed strong drug resistance property, and they were multidrug resistant. The most prevalent strain was PFGE type A.

Burns ; microbiology ; Drug Resistance, Multiple, Bacterial ; Humans ; Methicillin-Resistant Staphylococcus aureus ; drug effects