Proteus sp. – an opportunistic bacterial pathogen – classification, swarming growth, clinical significance and virulence factors

The genus Proteus belongs to the Enterobacteriaceae family, where it is placed in the tribe Proteeae, together with the genera Morganella and Providencia. Currently, the genus Proteus consists of five species: P. mirabilis, P. vulgaris, P. penneri, P. hauseri and P. myxofaciens, as well as three unnamed Proteus genomospecies. The most defining characteristic of Proteus bacteria is a swarming phenomenon, a multicellular differentiation process of short rods to elongated swarmer cells. It allows population of bacteria to migrate on solid surface. Proteus bacteria inhabit the environment and are also present in the intestines of humans and animals. These microorganisms under favorable conditions cause a number of infections including urinary tract infections (UTIs), wound infections, meningitis in neonates or infants and rheumatoid arthritis. Therefore, Proteus is known as a bacterial opportunistic pathogen. It causes complicated UTIs with a higher frequency, compared to other uropathogens. Proteus infections are accompanied by a formation of urinary stones, containing struvite and carbonate apatite. The virulence of Proteus rods has been related to several factors including fimbriae, flagella, enzymes (urease - hydrolyzing urea to CO2 and NH3, proteases degrading antibodies, tissue matrix proteins and proteins of the complement system), iron acqusition systems and toxins: hemolysins, Proteus toxin agglutinin (Pta), as well as an endotoxin - lipopolysaccharide (LPS). Proteus rods form biofilm, particularly on the surface of urinary catheters, which can lead to serious consequences for patients. In this review we present factors involved in the regulation of swarming phenomenon, discuss the role of particular pathogenic features of Proteus spp., and characterize biofilm formation by these bacteria

Effect of nutrient and stress factors on polysaccharides synthesis in Proteus mirabilis biofilm

The extracellular matrix in biofilm consists of water, proteins, polysaccharides, nucleic acids and phospholipids. Synthesis of these components is influenced by many factors, e.g. environment conditions or carbon source. The aim of the study was to analyse polysaccharides levels in Proteus mirabilis biofilms after exposure to stress and nutritional conditions. Biofilms of 22 P. mirabilis strains were cultivated for 24, 48, 72 hours, 1 and 2 weeks in tryptone soya broth or in modified media containing an additional amount of nutrients (glucose, albumin) or stress factors (cefotaxime, pH 4, nutrient depletion). Proteins and total polysaccharides levels were studied by Lowry and the phenol-sulphuric acid methods, respectively. Glycoproteins levels were calculated by ELLA with the use of selected lectins (WGA and HPA). For CLSM analysis dual fluorescent staining was applied with SYTO 13 and WGA-TRITC. In optimal conditions the levels of polysaccharides were from 0 to 442 μg/mg of protein and differed depending on the strains and cultivation time. The agents used in this study had a significant impact on the polysaccharides synthesis in the P. mirabilis biofilm. Among all studied components (depending on tested methods), glucose and cefotaxime stimulated the greatest production of polysaccharides by P. mirabilis strains (more than a twofold increase). For most tested strains the highest amounts of sugars were detected after one week of incubation. CLSM analysis confirmed the overproduction of N-acetyloglucosamine in biofilms after cultivation in nutrient and stress conditions, with the level 111-1134%, which varied depending on the P. mirabilis strain and the test factor

Antimicrobial, antiadhesive and antibiofilm potential of lipopeptides synthesised by Bacillus subtilis, on uropathogenic bacteria

The aim of this study was to investigate the antimicrobial effect of lipopeptide biosurfactants from surfactin, iturin and fengycin families, synthesised by the Bacillus subtilis I'1a strain, on uropathogenic bacteria, including the effects on planktonic growth, processes of biofilm formation and dislodging. Antimicrobial activity was tested against 32 uropathogenic strains belonging to 12 different species of Gram-negative and Gram-positive bacteria. The sensitivity of 25 tested bacterial strains to the B. subtilis I'1a filtrate was confirmed by an agar diffusion assay. None of the strains seemed to be sensitive to pure surfactin at concentrations ranging from 0.1 mg × ml-1 to 0.4 mg ml-1. After the treatment of uropathogens with B. subtilis lipopeptides, the metabolic activity of planktonic cells was inhibited by 88.05±3.96% in the case of 21 studied uropathogens, the process of biofilm formation was reduced by 88.15±4.77% in the case of 24 uropathogens and mature biofilms of 18 strains were dislodged by about 81.20±4.72%. Ten strains of uropathogenic bacteria were selected to study the antimicrobial activity of surfactin (concentrations 0.1, 0.2 and 0.4 mg × ml-1). Surfactin had no influence on the metabolic activity of planktonic forms of uropathogens, however, biofilms of 5 tested strains were reduced by 64.77±9.05% in the presence of this biosurfactant at the concentration 0.1 mg × ml-1. The negative effect of the compound on the biofilm formation process was observed at all concentrations used. The above-described results were fully confirmed by CLSM. It could suggest that synergistic application of biosurfactants could be efficient in uropathogen eradication

Proteus sp. – an opportunistic bacterial pathogen – classification, swarming growth, clinical significance and virulence factors

The genus Proteus belongs to the Enterobacteriaceae family, where it is placed in the tribe Proteeae, together with the genera Morganella and Providencia. Currently, the genus Proteus consists of five species: P. mirabilis, P. vulgaris, P. penneri, P. hauseri and P. myxofaciens, as well as three unnamed Proteus genomospecies. The most defining characteristic of Proteus bacteria is a swarming phenomenon, a multicellular differentiation process of short rods to elongated swarmer cells. It allows population of bacteria to migrate on solid surface. Proteus bacteria inhabit the environment and are also present in the intestines of humans and animals. These microorganisms under favorable conditions cause a number of infections including urinary tract infections (UTIs), wound infections, meningitis in neonates or infants and rheumatoid arthritis. Therefore, Proteus is known as a bacterial opportunistic pathogen. It causes complicated UTIs with a higher frequency, compared to other uropathogens. Proteus infections are accompanied by a formation of urinary stones, containing struvite and carbonate apatite. The virulence of Proteus rods has been related to several factors including fimbriae, flagella, enzymes (urease - hydrolyzing urea to CO2 and NH3, proteases degrading antibodies, tissue matrix proteins and proteins of the complement system), iron acqusition systems and toxins: hemolysins, Proteus toxin agglutinin (Pta), as well as an endotoxin - lipopolysaccharide (LPS). Proteus rods form biofilm, particularly on the surface of urinary catheters, which can lead to serious consequences for patients. In this review we present factors involved in the regulation of swarming phenomenon, discuss the role of particular pathogenic features of Proteus spp., and characterize biofilm formation by these bacteria

Benefits and Challenges of the Use of Two Novel vB_Efa29212_2e and vB_Efa29212_3e Bacteriophages in Biocontrol of the Root Canal Enterococcus faecalis Infections

Bacteriophage therapy has emerged as a strategy supplementing traditional disinfection protocols to fight biofilms. The aim of the study was to isolate the phages against E. faecalis and to characterize its biological features, morphology, and lytic activity in a formed biofilm model. Methods: E. faecalis ATCC 29212 strain was used for the trial. Two novel vB_Efa29212_2e and vB_Efa29212_3e virulent phages were isolated from urban wastewater and characterized. The E. faecalis biofilm was established in 15 bovine teeth for 21 days. Transmission (TEM) and scanning electron (SEM) microscopes with the colony-forming unit (CFU) counting were used for assessment. Results: Isolated phages differed in morphology. Taxonomy for vB_Efa29212_2e (Siphoviridae, Efquatovirus) and for vB_Efa29212_3e (Herelleviridae, Kochikohdavirus) was confirmed. Both phages were stable at a temperature range of 4–50 °C and showed a different tolerance to chemicals: 15% EDTA, 1–3% sodium hypochlorite, and chlorhexidine. SEM analysis showed distortion of bacteria cells after phage inoculation, which proved the lytic activity against E. faecalis. A 54.6% reduction in the E. faecalis biofilm confirmed bacteriophage efficacy against isolates in the ex vivo model. Conclusions: Results strongly support the concept that phage therapy has a real therapeutic potential for the prevention and treatment of E. faecalis-associated infections