Escherichia coli Strains Responsible for Cystitis in Female Pediatric Patients with Normal and Abnormal Urinary Tracts Have Different Virulence Profiles.

The role of uropathogenic Escherichia coli (UPEC) in colonization and infection of female patients with anatomical and functional abnormalities of the urinary system is elusive. In this study, the phenotype, genotype and the phylogeny of UPEC strains isolated from the urine of pediatric female patients with cystitis of normal and abnormal urinary tract were determined. Multiplex PCR results demonstrated that 86% of the strains isolated from female patients with normal urinary tract (NUT), belonged to the phylo-groups B2 and D. Their prevalence decreased to 23% in strains isolated from patients with abnormal urinary tract (AUT). More of the isolates from AUT patients produced a biofilm on polystyrene and polyvinyl chloride (PVC), adhered to epithelial cells, and encoded pap and sfa genes than strains isolated from female patients with NUT. In contrast, a higher number of hemolysin-producing strains with serogroups associated with UPEC were isolated from patients with NUT. In summary, the results suggest that cystitis in female patients with NUT is associated with ExPEC, whereas cystitis in female patients with AUT is associated with pathogenic intestinal E. coli strains that have acquired the ability to colonize the bladder.

A new class of antimicrobial molecules derived from kefir, effective against Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus (MRSA) strains.

Many studies have linked the antimicrobial properties of kefir with the presence of bacteriocins and organic acids. In the present work, results obtained from bacteriostatic and bactericidal studies, and from RP-HPLC, Mass Spectrometry and proton NMR analysis, show that a sample of milk kefir grains is able to produce an antimicrobial fraction, denoted FK-1000, composed of sugars and amino acids, predominantly polymers of alanine, doublets of tyrosine and phenylalanine. Since this fraction is a lyophilized product whose molecular profile is different from bacteriocins and simple carboxylic acids, its antimicrobial effect cannot be attributed to these molecules, or to alcohols or hydrogen peroxide. The fraction is bactericidal against weak-acid-resistant MRSA and weak-acid resistant P. aeruginosa at pH 5, and is bacteriostatic against both pathogens at pH 7. In combination formulation, the FK-1000 fraction is able to increase fivefold the effect of streptomycin against P. aeruginosa and it is not toxic to human epithelial cells at antimicrobial concentrations. 16 S rRNA microbiota analysis of antimicrobial-producing and non-producing kefir grains demonstrated that they are distinct. In summary, the results indicate that milk kefir grains can produce different classes of molecules with potent antibiotic activity against resistant bacteria.

A new class of antimicrobial molecules derived from kefir, effective against Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus (MRSA) strains

Many studies have linked the antimicrobial properties of kefir with the presence of bacteriocins and organic acids. In the present work, results obtained from bacteriostatic and bactericidal studies, and from RP-HPLC, Mass Spectrometry and proton NMR analysis, show that a sample of milk kefir grains is able to produce an antimicrobial fraction, denoted FK-1000, composed of sugars and amino acids, predominantly polymers of alanine, doublets of tyrosine and phenylalanine. Since this fraction is a lyophilized product whose molecular profile is different from bacteriocins and simple carboxylic acids, its antimicrobial effect cannot be attributed to these molecules, or to alcohols or hydrogen peroxide. The fraction is bactericidal against weak-acid-resistant MRSA and weak-acid resistant P. aeruginosa at pH 5, and is bacteriostatic against both pathogens at pH 7. In combination formulation, the FK-1000 fraction is able to increase fivefold the effect of streptomycin against P. aeruginosa and it is not toxic to human epithelial cells at antimicrobial concentrations. 16 S rRNA microbiota analysis of antimicrobial-producing and non-producing kefir grains demonstrated that they are distinct. In summary, the results indicate that milk kefir grains can produce different classes of molecules with potent antibiotic activity against resistant bacteria.

The potential of Loxosceles gaucho spider venom to regulate Pseudomonas aeruginosa mechanisms of virulence.

Loxosceles venom is a potential source of bioactive molecules which may be transformed into antimicrobial products against multi-resistant bacteria. Here, it was investigated whether Loxosceles gaucho spider had any influence on the proliferation, enzyme release and biofilm formation of a Pseudomonas aeruginosa strain resistant to two different classes of antibiotic. The results demonstrated that L. gaucho whole venom has no influence on P. aeruginosa proliferation. However, it increases P. aeruginosa production of gelatinase, caseinase and biofilm formation. The same effects were noted when P. aeruginosa was exposed to a L. gaucho venom molecular fraction with mass lower than 1 kDa. Separation of this molecular fraction into different subsets by RP-HPLC demonstrated that, among the molecules with the ability to increase the production of enzymes and biofilm formation, there are some with antimicrobial activities whose effects are not observed in the whole venom. In summary, the results obtained herein indicate that L. gaucho venom has a variety of low molecular mass bioactive components that influence the mechanisms of virulence of P. aeruginosa in different ways.

The potential of Loxosceles gaucho spider venom to regulate Pseudomonas aeruginosa mechanisms of virulence

Loxosceles venom is a potential source of bioactive molecules which may be transformed into antimicrobial products against multi-resistant bacteria. Here, it was investigated whether Loxosceles gaucho spider had any influence on the proliferation, enzyme release and biofilm formation of a Pseudomonas aeruginosa strain resistant to two different classes of antibiotic. The results demonstrated that L. gaucho whole venom has no influence on P. aeruginosa proliferation. However, it increases P. aeruginosa production of gelatinase, caseinase and biofilm formation. The same effects were noted when P. aeruginosa was exposed to a L. gaucho venom molecular fraction with mass lower than 1 kDa. Separation of this molecular fraction into different subsets by RP-HPLC demonstrated that, among the molecules with the ability to increase the production of enzymes and biofilm formation, there are some with antimicrobial activities whose effects are not observed in the whole venom. In summary, the results obtained herein indicate that L. gaucho venom has a variety of low molecular mass bioactive components that influence the mechanisms of virulence of P. aeruginosa in different ways.

The potential of Loxosceles gaucho spider venom to regulate Pseudomonas aeruginosa mechanisms of virulence

Loxosceles venom is a potential source of bioactive molecules which may be transformed into antimicrobial products against multi-resistant bacteria. Here, it was investigated whether Loxosceles gaucho spider had any influence on the proliferation, enzyme release and biofilm formation of a Pseudomonas aeruginosa strain resistant to two different classes of antibiotic. The results demonstrated that L. gaucho whole venom has no influence on P. aeruginosa proliferation. However, it increases P. aeruginosa production of gelatinase, caseinase and biofilm formation. The same effects were noted when P. aeruginosa was exposed to a L. gaucho venom molecular fraction with mass lower than 1 kDa. Separation of this molecular fraction into different subsets by RP-HPLC demonstrated that, among the molecules with the ability to increase the production of enzymes and biofilm formation, there are some with antimicrobial activities whose effects are not observed in the whole venom. In summary, the results obtained herein indicate that L. gaucho venom has a variety of low molecular mass bioactive components that influence the mechanisms of virulence of P. aeruginosa in different ways.