The influence of environmental factors (temperature, aerobiosis-anaerobiosis, static-dynamic conditions, pH) was determined on biofilm formation by 51 S. maltophilia clinical isolates. The strains produced more biofilm at 32 degrees C than at 37 or 18 degrees C. Aerobic and 6% CO2 atmosphere yielded comparable biofilm amounts, higher than under anaerobic conditions. Biofilm production was not affected by static vs. agitated culture conditions. Biofilm production at pH 7.5 and 8.5 was comparable but significantly higher than at pH 5.5. The capacity of individual strains to form biofilm and thus contribute to the severity of some diseases is influenced by host traits and environmental conditions at the site of infection, and play an important role in the pathogenesis of biomaterial-related disease caused by S. maltophilia.

• MeSH
• Aerobiosis MeSH
• Anaerobiosis MeSH
• Biofilms growth & development   MeSH
• Gram-Negative Bacterial Infections microbiology   MeSH
• Hydrogen-Ion Concentration MeSH
• Culture Media MeSH
• Humans MeSH
• Gene Expression Regulation, Bacterial * MeSH
• Stenotrophomonas maltophilia growth & development   isolation & purification   MeSH
• Temperature * MeSH
• Environment * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Culture Media MeSH

Due to high resistance, standard chemotherapy of biofilm-associated staphylococcal infections is ineffective and a number of alternative approaches to antimicrobial treatment have been proposed. Minimum inhibitory concentration (MIC) and biofilm inhibitory concentration (BIC) of oxacillin (Oxa), vancomycin (Van), linezolid (Lzd) and lysostaphin (Lss) as well as the possible synergistic effect of the antibiotics and lysostaphin were determined. The Lss susceptibility of Staphylococcus aureus planktonic and bio-film cultures varied and was strain-dependent. The synergistic effect of sub-BIC(Lss)+Oxa was observed for methicillin-sensitive S. aureus (MSSa) and methicillin-resistant S. aureus (MrSa), but not for heterogeneously vancomycin-resistant S. aureus (V(h)Sa) biofilm. Van with sub-BICL(Lss) was effective against M(s)Sa and MrSa biofilm, when applied in three subsequent doses. Only sub-BICL(Lss)+Lzd combination, given as three cycles therapy, was effective in disruption of all 3 (M(s)Sa, M(r)Sa, V(h)Sa) biofilms.

• MeSH
• Acetamides pharmacology   MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Biofilms drug effects   growth & development   MeSH
• Drug Therapy, Combination MeSH
• Microscopy, Confocal MeSH
• Humans MeSH
• Linezolid MeSH
• Lysostaphin pharmacology   MeSH
• Microbial Sensitivity Tests MeSH
• Oxacillin pharmacology   MeSH
• Oxazolidinones pharmacology   MeSH
• Staphylococcal Infections drug therapy   MeSH
• Staphylococcus aureus drug effects   MeSH
• Vancomycin pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Acetamides MeSH
• Anti-Bacterial Agents MeSH
• Linezolid MeSH
• Lysostaphin MeSH
• Oxacillin MeSH
• Oxazolidinones MeSH
• Vancomycin MeSH

Resistance to 17 antimicrobials, surface hydrophobicity, motility, biofilm, production of N-acylhomoserine lactone signal molecules (N-butyrylhomoserine lactone and N-3-oxolauroylhomoserine lactone) and response to oxidative stress were analyzed in 47 clinical Pseudomonas aeruginosa strains. In addition to natural resistance, the strains demonstrated the greatest level of resistance to cefotaxime (91.5%). Isolates in the range of 44.7-57.4% were resistant to aminoglycosides and ciprofloxacin, of 25.5-36.2% to cephalosporins. On the other hand, 97.9% remained susceptible to meropenem, 93.6% to piperacillin + tazobactam and 87.2% to piperacillin. The majority of the strains (72.3%) manifested their hydrophilic character. Higher zones of motility showed 12 isolates (in average 54.8 mm) as compared to the others (30.2 mm). Approximately 1/3 of the strains (29.8%) produced a higher amount of biofilm quantified by measuring the absorbance of solubilized crystal violet (0.20-0.46) than the rest of isolates (0-0.19). All but two strains produced N-3-oxolauroylhomoserine lactone and in 48.9% of samples N-butyrylhomoserine lactone were detected. Only four isolates with higher biofilm production showed both types of homoserine lactone. Majority of the strains (70.2%) manifested higher resistance to H2O2 than the rest of the strains. The group of strains resistant to aminoglycosides and ciprofloxacin revealed a significantly higher number of hydrophobic strains (compared with the sensitive ones). In contrast, higher number of strains sensitive to aminoglycosides and ciprofloxacin or only to ciprofloxacin produced N-butyrylhomoserine lactone and biofilm (compared to the resistant ones). Such association was not found among the rest of the tested parameters. The results indicate that the resistance to antimicrobials in P. aeruginosa isolates was not generally associated with changes in the production of the pathogenicity factors.

• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Drug Resistance, Bacterial * MeSH
• Biofilms growth & development   MeSH
• Phenotype MeSH
• Adaptation, Physiological MeSH
• 4-Butyrolactone analogs & derivatives   biosynthesis   MeSH
• Gentian Violet metabolism   MeSH
• Hydrophobic and Hydrophilic Interactions MeSH
• Humans MeSH
• Oxidative Stress MeSH
• Oxidants pharmacology   MeSH
• Hydrogen Peroxide pharmacology   MeSH
• Movement MeSH
• Pseudomonas Infections microbiology   MeSH
• Pseudomonas aeruginosa drug effects   isolation & purification   pathogenicity   MeSH
• Virulence MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• 4-Butyrolactone MeSH
• Gentian Violet MeSH
• Oxidants MeSH
• Hydrogen Peroxide MeSH

Effect of pH on production of extracellular virulence factors of Pseudomonas aeruginosa grown on catheter in biofilm was determined. Alginate and proteinase production was higher at pH 8; in contrast, siderophores (pyochelin and pyoverdin) were synthesized more intensively at pH 5.

• MeSH
• Alginates metabolism   MeSH
• Bacterial Proteins metabolism   MeSH
• Biofilms growth & development   MeSH
• Virulence Factors biosynthesis   MeSH
• Hydrogen-Ion Concentration MeSH
• Culture Media, Conditioned chemistry   MeSH
• Glucuronic Acid metabolism   MeSH
• Hexuronic Acids metabolism   MeSH
• Humans MeSH
• Urine microbiology   MeSH
• Peptide Hydrolases metabolism   MeSH
• Pseudomonas Infections microbiology   MeSH
• Pseudomonas aeruginosa growth & development   metabolism   pathogenicity   physiology   MeSH
• Siderophores metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Alginates MeSH
• Bacterial Proteins MeSH
• Virulence Factors MeSH
• Culture Media, Conditioned MeSH
• Glucuronic Acid MeSH
• Hexuronic Acids MeSH
• Peptide Hydrolases MeSH
• Siderophores MeSH