The ability to form biofilms is a recognized trait of Stenotrophomonas maltophilia, but the extent of its clinical relevance is still unclear. The present multicenter prospective study (ANSELM) aims at investigating the association between biofilm formation and clinical outcomes of S. maltophilia infections. One hundred and nine isolates were collected from various geographical origins and stratified according to their clinical relevance. Biofilm formation was evaluated by the microtiter plate assay and correlated with microbiological and clinical data from the associated strains. Antibiotic susceptibility of the planktonic cells was tested by the disk diffusion technique, while antibiotic activity against mature biofilms was spectrophotometrically assessed. Most strains (91.7%) were able to form biofilm, although bloodborne strains produced biofilm amounts significantly higher than strains causing hospital- rather than community-acquired infections, and those recognized as "definite" pathogens. Biofilm formation efficiency was positively correlated with mechanical ventilation (p = 0.032), whereas a negative relationship was found with antibiotic resistance (r2 = 0.107; p < 0.001), specifically in the case of the pathogenic strains. Mature S. maltophilia biofilms were markedly more resistant (up to 128 times) to cotrimoxazole and levofloxacin compared with their planktonic counterparts, especially in the case of bloodborne strains. Our findings indicate that biofilm formation by S. maltophilia is obviously a contributing factor in the pathogenesis of infections, especially in deep ones, thus warranting additional studies with larger cohort of patients and isolates.

• Keywords
• Stenotrophomonas maltophilia, antibiotic resistance, biofilm formation, clinical relevance, multicenter study,
• Publication type
• Journal Article MeSH

In this study, 99 Gram-negative rod bacteria were isolated from cooling tower water, and biofilm samples were examined for cell-to-cell signaling systems, N-acyl homoserine lactone (AHL) signal molecule types, and biofilm formation capacity. Four of 39 (10 %) strains isolated from water samples and 14 of 60 (23 %) strains isolated from biofilm samples were found to be producing a variety of AHL signal molecules. It was determined that the AHL signal molecule production ability and the biofilm formation capacity of sessile bacteria is higher than planktonic bacteria, and there was a statistically significant difference between the AHL signal molecule production of these two groups (p < 0.05). In addition, it was found that bacteria belonging to the same species isolated from cooling tower water and biofilm samples produced different types of AHL signal molecules and that there were different types of AHL signal molecules in an AHL extract of bacteria. In the present study, it was observed that different isolates of the same strains did not produce the same AHLs or did not produce AHL molecules, and bacteria known as AHL producers did not produce AHL. These findings suggest that detection of signal molecules in bacteria isolated from cooling towers may contribute to prevention of biofilm formation, elimination of communication among bacteria in water systems, and blockage of quorum-sensing controlled virulence of these bacteria.

• MeSH
• Acyl-Butyrolactones chemistry   isolation & purification   metabolism   MeSH
• Biofilms growth & development   MeSH
• Bacterial Physiological Phenomena * MeSH
• Gram-Negative Bacteria isolation & purification   metabolism   MeSH
• Water Microbiology * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Acyl-Butyrolactones MeSH

The minimum inhibitory concentrations (MICs) of 24 antibiotics were determined for 45 Stenotrophomonas maltophilia strains by the microdilution method at 37 and 30 degrees C (after 24 h and 48 h of incubation). The isolates were obtained from mouth swabs and pus of 116 captive snakes whereas the identical strains (based on PFGE) of the same origin were discarded. At 37 degrees C, the isolates showed a low frequency of resistance to levofloxacin (0 and 8.9 % of resistant strains after 24 and 48 h, MICs(50) 0.5 and 1 mg/L, MICs(90) 1 and 2 mg/L) and cotrimoxazole (2.2 % of resistant strains for 24 and 48 h, MICs(50) 4 mg/L for both time periods, MICs(90) 4 and 8). At 30 degrees C, the most effective drugs were also cotrimoxazole (2.2 and 6.7 %, MICs(50) 4 and 8, MICs(90) 8 and 32) and levofloxacin (8.9 and 46.7 %, MICs(50) 1 and 2, MICs(90) 2 and 4). The isolates were either identically or more susceptible to antibiotics than strains acquired from patients hospitalized at Olomouc University Hospital (the same region) with the exception of ciprofloxacin, cefoperazone, cefoperazone/sulbactam and ceftazidime.

• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Drug Resistance, Bacterial * MeSH
• Gram-Negative Bacterial Infections microbiology   veterinary   MeSH
• Snakes microbiology   MeSH
• Suppuration microbiology   MeSH
• Microbial Sensitivity Tests MeSH
• Carrier State microbiology   veterinary   MeSH
• Stenotrophomonas maltophilia drug effects   isolation & purification   MeSH
• Mouth microbiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH

The effect of different cultivation temperatures (30 and 37 degrees C) and pH of the media (5.5, 7.5, 8.5) on the biofilm production was compared in Pseudomonas aeruginosa, Klebsiella pneumoniae, and Vibrio cholerae non-O1 and O1 using the crystal-violet test for estimation of quantitative production of the biofilm. Decrease (46.4-98.4 %) in the biofilm production was observed at 37 degrees C in 8 of the tested strains (P. aeruginosa three strains, K pneumoniae two, V. cholerae non-O1 two, and V. cholerae O1 one strain) compared with the production at 30 degrees C. On the other hand, five strains (P. aeruginosa 1, K. pneumoniae 3, V. cholerae non-O1 1) exhibited under these conditions a higher biofilm production (103-143 %). However, this difference was not significant (p = 0.196). Increased pH lead to a higher biofilm production using all media tested. In P. aeruginosa the biofilm production at pH 8.5 was 139-244 %, at pH 7.5 136-164 % in comparison with pH 5.5. Similarly, in K. pneumoniae the biofilm production increased to 151-319 % at pH 8.5 while with the drop of pH to 7.5 the biofilm production was 113-177 % compared with pH 5.5. In V. cholerae non-O1 and O1 the biofilm production reached 204-329 % at pH 8.5, and 123-316 % at pH 7.5 (compared with the production at pH 5.5). An increase in biofilm production represented an average of 169 % (p = 0.001) at pH change from 5.5 to 7.5, with the rise of pH from 5.5 to 8.5 caused an average difference of 229 % (p = 0.001).

• MeSH
• Staining and Labeling MeSH
• Coloring Agents pharmacology   MeSH
• Biofilms drug effects   growth & development   radiation effects   MeSH
• Gentian Violet pharmacology   MeSH
• Klebsiella pneumoniae drug effects   growth & development   radiation effects   MeSH
• Hydrogen-Ion Concentration MeSH
• Humans MeSH
• Pseudomonas aeruginosa drug effects   growth & development   radiation effects   MeSH
• Temperature MeSH
• Vibrio cholerae non-O1 drug effects   growth & development   radiation effects   MeSH
• Vibrio cholerae O1 drug effects   growth & development   radiation effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Coloring Agents MeSH
• Gentian Violet MeSH

The possible presence of biofilms was examined in mucosal specimens of 15 patients, undergoing functional endoscopic sinus surgery or a modified Caldwell-Luc approach for chronic rhinosinusitis (CRS). Biofilms were found in 7 of the 15 patients, positive cultures being obtained in most samples, which supports the role of biofilms as an important factor in the pathogenesis of CRS.

• MeSH
• Biofilms growth & development   MeSH
• Chronic Disease MeSH
• Adult MeSH
• Endoscopy MeSH
• Middle Aged MeSH
• Humans MeSH
• Microscopy, Electron, Scanning MeSH
• Adolescent MeSH
• Young Adult MeSH
• Nasal Mucosa microbiology   ultrastructure   MeSH
• Rhinitis microbiology   surgery   MeSH
• Sinusitis microbiology   surgery   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH