Magdalena Strus

Visible light inactivation of bacteria and fungi by modified titanium dioxide.

Visible light induced photocatalytic inactivation of bacteria (Escherichia coli, Staphylococcus aureus, Enterococcus faecalis) and fungi (Candida albicans, Aspergillus niger) was tested. Carbon-doped titanium dioxide and TiO2 modified with platinum(IV) chloride complexes were used as suspension or immobilised at the surface of plastic plates. A biocidal effect was observed under visible light irradiation in the case of E. coli in the presence of both photocatalysts. The platinum(IV) modified titania exhibited a higher inactivation effect, also in the absence of light. The mechanism of visible light induced photoinactivation is briefly discussed. The observed detrimental effect of photocatalysts on various microorganism groups decreases in the order: E. coli > S. aureus approximately E. faecalis>>C. albicans approximately A. niger. This sequence results most probably from differences in cell wall or cell membrane structures in these microorganisms and is not related to the ability of catalase production.

The in vitro Activity of Vaginal Lactobacillus With Probiotic Properties Against Candida

Lactobacilli, the predominant vaginal microorganisms in healthy premenopausal women, control other members of the vaginal microflora and thus protect against bacterial vaginosis and urinary tract infections. It has been claimed that some lactobacilli are also protective against Candida vaginitis. Little is known, however, about the mechanisms by which these lactobacilli can control vaginal populations of Candida and prevent vaginitis. To address this question, vaginal Lactobacillus strains with known antagonistic properties against bacteria were tested for their cell surface properties, adhesion to vaginal cell lines in vitro and antagonistic activities against Candida. A small proportion of the lactobacilli tested adhered strongly to cultured vaginal epithelial cells and inhibited growth of Candida albicans but not of C. pseudotropicalis. This anticandidal activity was in some Lactobacillus strains related to hydrogen peroxide (H2O2) production, but catalase treatment did not suppress this activity in other Lactobacillus strains, suggesting alternative mechanism(s). Moreover, tested vaginal Candida strains were resistant to relatively high concentrations of H2O2 that markedly exceeded those produced by even the most active Lactobacillus strains.

Studies on the effects of probiotic Lactobacillus mixture given orally on vaginal and rectal colonization and on parameters of vaginal health in women with intermediate vaginal flora

OBJECTIVES The vaginal microflora is composed of many bacterial species and plays a major role in maintaining the balance of this complex environment. This study was conducted in order to assess the degree and persistence of the colonization of vaginal epithelium by strains from an orally administered mixture of lactobacilli, containing Lactobacillus fermentum 57A, Lactobacillus plantarum 57B and Lactobacillus gasseri 57C. We also monitored its effects on parameters of vaginal health, especially total lactobacilli counts, vaginal pH and Nugent score. STUDY DESIGN The patient group in this open study consisted of clinically healthy women with intermediate vaginal flora. Altogether 37 women were included in the study; 25 finished the full cycle consisting of 8 visits during 70 days. Lactobacillus mixture was administered as 1×10(8) c.f.u. once a day for 60 days. Lactobacillus isolates collected from vaginal and rectal samples from studied women during all visits were typed using molecular methods (PFGE for L. fermentum and L. gasseri and MLST for L. plantarum). Total lactobacilli counts, vaginal pH and Nugent score were also determined during the visits. RESULTS We confirmed that the ingested strains were able to reach and colonize both sites within the third and eighth visits, i.e. between the 20th and 70th days of the study. Maximal colonization was recorded between the fifth and seventh visits (31st-60th days). Moreover, ingestion of the Lactobacillus mixture was related to normalization of vaginal parameters (within 28-60 days after the initiation of the treatment). This was demonstrated by a decrease of vaginal pH and Nugent score together with an increase of total numbers of lactobacilli in the vagina and rectum. No adverse events were noted during the course of the study. CONCLUSIONS Oral application of the combination of the three probiotic strains derived from vaginal microbiota of healthy woman with high adherence abilities to both vaginal and colonic epithelium in vitro shows that both individual strains and their mixture can colonize vagina for some weeks, the effect of which is correlated with significant improvement of such parameters like pH and Nugent score values and total numbers of vaginal lactobacilli. This indicates that the mixture may be a good candidate for the planned double-blind, placebo-controlled randomized studies involving larger numbers of women.

Structural and immunochemical studies of neutral exopolysaccharide produced by Lactobacillus johnsonii 142.

This paper describes the structure of neutral exopolysaccharide (EPS) produced by Lactobacillus johnsonii 142, strain of the lactic acid bacteria isolated from the intestine of mice with experimentally induced inflammatory bowel disease (IBD). Sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including two-dimensional (1)H,(1)H COSY, TOCSY, NOESY, and (1)H,(13)C HSQC experiments revealed that the repeating unit of the EPS is a pentasaccharide: -->3)-alpha-D-Galp-(1-->3)-beta-d-Glcp-(1-->5)-beta-D-Galf-(1-->3)-alpha-D-Galp-(1-->3)-alpha-D-Galp-(1--> The rabbit antiserum raised against whole cells of L. johnsonii 142 reacted with homologous EPS, and cross-reacted with exopolysaccharide from Lactobacillus animalis/murinus 148 isolated also from mice with IBD, but not reacted with EPS of L. johnsonii 151 from healthy mice.

Differential inflammatory mediator response in vitro from murine macrophages to lactobacilli and pathogenic intestinal bacteria

Chronic active colitis (including inflammatory bowel disease – IBD) is maintained by a variety of pro‐inflammatory mediators. Certain intestinal bacterial strains may induce colitis, whereas some strains (e.g. Lactobacillus spp.) show a protective effect in colitis owing to their anti‐inflammatory activity. In this study, we have examined the production of selected inflammatory cytokines, reactive oxygen species (ROS), nitric oxide (NO) and the expression of haeme oxygenase‐1 (HO‐1) by murine peritoneal macrophages stimulated in vitro by the intestinal bacterial strains, isolated from mice with colitis. Lactobacillus strains (Lactobacillus reuteri, L. johnsonii, L. animalis/murinus) and two potentially pathogenic bacteria (Escherichia coli and Enterococcus faecalis) induced the production of substantial amounts of cytokines with a strain specific profile. Despite some interstrain differences, all lactobacilli induced production of anti‐inflammatory cytokines (IL‐10high, IL‐6low, IL‐12p70low). Conversely, E. faecalis and E. coli induced the production of proinflammatory cytokines (TNF‐α, IL‐12p70), the cytokines essential for chronic IBD. Macrophages released comparably substantial amounts of ROS in response to all Lactobacillus strains tested, while E. coli and E. faecalis ability to induce generation of ROS was negligible. In contrast to ROS, the production of NO/NO2− by macrophages activated with all bacterial strains tested was similar. Moreover, for the first time, it has been shown that intestinal bacteria differed in their ability to induce expression of HO‐1, a stress‐inducible enzyme with antioxidant and anti‐inflammatory properties. The beneficial immunoregulatory properties of candidate probiotic bacteria for the treatment of IBD are discussed.

Structural analysis of the Lactobacillus rhamnosus strain KL37C exopolysaccharide.

The exopolysaccharide from the lactic acid bacterium Lactobacillus rhamnosus strain KL37C isolated from human intestinal flora was prepared by sonication of bacterial cell mass suspended in water followed by centrifugation and cold ethanol precipitation of the supernatant. The polysaccharide material was purified by gel permeation chromatography on an TSK HW-50 column and characterised using chemical and enzymatic methods. On the basis of sugar and methylation analysis and 1H, 13C, 1D and 2D NMR spectroscopy the exopolysaccharide was shown to be composed of the following pentasaccharide repeating unit:-->3)-alpha-D-Glcp-(1-->2)-beta-D-Galf-(1-->6)-alpha-D-Galp-(1-->6)-alpha-D-Glcp-(1-->3)-beta-D-Galf-(1-->

Virulence factors of Enterococcus strains isolated from patients with inflammatory bowel disease

AIM To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n = 16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro. RESULTS A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of the asa1 gene and the gelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain of Enterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent among Enterococcus strains isolated from children with IBD than in control strains. CONCLUSION Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.

The structure and immunoreactivity of exopolysaccharide isolated from Lactobacillus johnsonii strain 151

The exopolysaccharide (EPS) structure from Lactobacillus johnsonii strain 151 isolated from the intestinal tract of mice was investigated. Sugar and methylation analyses together with (1)H and (13)C NMR spectroscopy, including two-dimensional (1)H,(1)H COSY, TOCSY, NOESY, and (1)H,(13)C HSQC, HMBC experiments, revealed that the repeating unit of the EPS is the linear pentasaccharide: →6)-α-d-Galp-(1→6)-α-d-Glcp-(1→3)-β-d-Galf-(1→3)-α-d-Glcp-(1→2)-β-d-Galf-(1→ The immunoreactivity of two structurally different exopolysaccharides isolated from L. johnsonii, 151 and 142 (Carbohydr. Res. 2010, 345, 108-114), was compared. Both EPSs differed in their reactivity with antisera. EPS from L. johnsonii 151 reacted with anti-Lactobacillus polyclonal sera against cells of five different strains, while EPS from L. johnsonii 142 was found to react only with its own antiserum. The broader specificity and higher reactivity of EPS from 151 strain than EPS from 142 strain were also observed with human sera. The physiological antibodies recognizing polysaccharide antigens were present in both adults and umbilical cord blood sera. A highly specific EPS 142 bearing strain was isolated from experimentally induced inflammatory bowel disease (IBD) mice, while a strain with EPS 151 isolated from the intestinal tract of healthy mice is characterized by a broad immune reactivity common structure.

Genetic characterization and diversity of Streptococcus agalactiae isolates with macrolide resistance.

Macrolide resistance in 169 Streptococcus agalactiae [group B streptococcus (GBS)] isolates originating from pregnant carriers was investigated. Using multiplex PCR the presence of genes encoding erythromycin resistance and capsular polysaccharides, as well as surface proteins, was determined. Random amplification of polymorphic DNA (RAPD) and PFGE were used to characterize specific clones among the isolates. In the examined population of women, erythromycin-resistant strains were found in 4.5 % of patients, whereas clindamycin-resistant strains were found in 3 % of patients, which was 16 % of strains resistant to erythromycin and 10 % of strains resistant to clindamycin among GBS isolates, respectively. Among the isolates, the largest percentage was represented by the constitutive macrolide-lincosamide-streptogramin B (cMLS(B)) phenotype (63 %), then the inductive macrolide-lincosamide-streptogramin B (iMLS(B)) phenotype (26 %) and the macrolide resistance (M) phenotype (11 %). The ermB gene was indicated in all isolates with the cMLS(B) phenotype and V serotype, whereas mefA/mefE genes were found in isolates with the M phenotype and Ia serotype. Among resistance isolates, serotype V was predominant (67 %), followed by serotypes II (15 %), Ia (11 %) and III (7 %). The most common surface protein encoding genes were alp3 (70 %), then rib (11 %), epsilon (7.5 %), bca (7.5 %) and alp2 (4 %). A statistically significant relationship between macrolide resistance, serotype V and the alp3 gene was demonstrated. PFGE, in comparison to the RAPD method, gave better genetic discrimination of GBS isolates. A relatively high genetic diversity among investigated strains was shown. In addition, the largest genetic homogeneity was found in serotype V.

Group B streptococcus colonization of pregnant women and their children observed on obstetric and neonatal wards of the University Hospital in Krakow, Poland.

The study was arranged to assess the actual rates of colonization of pregnant women and their children with group B streptococcus (GBS) in a Polish university hospital. Resistance of these cocci to macrolides and clindamycin was also tested and routes of transmission of GBS were followed in some cases using molecular typing. Colonization with GBS was checked in 340 pregnant women living in the south-eastern region of Poland (Małopolska) in the years 2004-2006. Women with a complicated pregnancy were more often colonized than those with a normal pregnancy (20.0 % versus 17.2 %). Moreover, women with a complicated pregnancy were twice as often colonized with GBS strains with the MLS(B) phenotype indicating resistance to macrolides and clindamycin. Regarding neonatal colonization by GBS, we found that neonates born from the colonized mothers with a complicated pregnancy were more often colonized with GBS than those from the mothers with a normal pregnancy (35 % versus 26.7 %). By molecular typing of the GBS strains isolated from mothers and their newborns we have been able to suggest the possibility of horizontal transmission of the strains from the hospital environment to newborns. Our results clearly indicate that rates of GBS colonization among pregnant women and neonates in a Polish university hospital have reached levels comparable to those reported in other European clinical centres.