Piotr B. Heczko

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.

Treatment of acute infectious diarrhoea in infants and children with a mixture of three Lactobacillus rhamnosus strains: a randomized, double-blind, placebo-controlled trial

Background  Multiple studies document that probiotics are effective in treating infectious diarrhoea in children. Lactobacillus rhamnosus GG is the most extensively studied but effectiveness of other strains has been poorly examined.

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.

Actinomycotic osteomyelitis of the mandible: review of 15 cases

The authors have analysed 15 cases of actinomycotic osteomyelitis of the mandible. Primary actinomycotic inflammation of the mandible was diagnosed in nine patients, secondary in six patients (following fracture or resection of the mandible). The diagnosis was established on the basis of the clinical examination confirmed by bacteriological and/or histopathological tests. The basic method of treatment was antibiotic therapy of long duration. Surgical treatment was performed in all patients. Twelve of fifteen patients who had received the therapy and proved asymptomatic for 1 year to 23 years were recognized to be cured of the disease. In three patients, a single recurrence of the disease was observed after 1.5-2 months.

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.

Are there regional variations in the diagnosis surveillance, and control of methicillin-resistant Staphylococcus aureus?

OBJECTIVE To assess the way healthcare facilities (HCFs) diagnose, survey, and control methicillin-resistant Staphylococcus aureus (MRSA). DESIGN Questionnaire. SETTING Ninety HCFs in 30 countries. RESULTS Evaluation of susceptibility testing methods showed that 8 laboratories (9%) used oxacillin disks with antimicrobial content different from the one recommended, 12 (13%) did not determine MRSA susceptibility to vancomycin, and 4 (4.5%) reported instances of isolation of vancomycin-resistant S. aureus but neither confirmed this resistance nor alerted public health authorities. A MRSA control program was reported by 55 (61.1%) of the HCFs. The following isolation precautions were routinely used: hospitalization in a private room (34.4%), wearing of gloves (62.2%), wearing of gowns (44.4%), hand washing by healthcare workers (53.3%), use of an isolation sign on the patients door (43%), or all four. When the characteristics of HCFs with low incidence rates (< 0.4 per 1,000 patient-days) were compared with those of HCFs with high incidence rates (> or = 0.4 per 1,000 patient-days), having a higher mean number of beds per infection control nurse was the only factor significantly associated with HCFs with high incidence rates (834 vs 318 beds; P = .02). CONCLUSION Our results emphasize the urgent need to strengthen the microbiologic and epidemiologic capacities of HCFs worldwide to prevent MRSA transmission and to prepare them to address the possible emergence of vancomycin-resistant S. aureus.

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-->

Conversion of OXA-66 into OXA-82 in clinical Acinetobacter baumannii isolates and association with altered carbapenem susceptibility

OBJECTIVES Three clinical Acinetobacter baumannii isolates (A-C) were isolated from three separate patients during an outbreak in a hospital in Krakow, Poland. Isolate A was recovered first and was susceptible to carbapenems, whereas isolates B and C were resistant. The aim of this study was to investigate the differences in carbapenem susceptibility in these outbreak-related isolates. METHODS Clonal relatedness was determined using rep-PCR-based DiversiLab. The bla(OXA-51-like) genes and their upstream regions were sequenced. Expression of the genes encoding OXA-51-like and the three major porins CarO, OprD-like and 33-36 kDa Omp were investigated by semi-quantitative RT-PCR. Comparison of outer membrane protein (OMP) profiles was performed using SDS-PAGE. ISAba1-bla(OXA-82) was cloned into the shuttle vector pWH1266 and transferred into A. baumannii ATCC 17978. RESULTS The isolates were identical by rep-PCR and clustered with international clonal lineage 2. Sequencing of bla(OXA-51-like) revealed a conversion of OXA-66 (isolate A) into OXA-82 (isolates B and C). bla(OXA-82) was also associated with ISAba1. Expression analysis revealed overexpression of bla(OXA-82). There was no difference in OMP expression between the isolates. ISAba1-bla(OXA-82) conferred carbapenem resistance in ATCC 17978. CONCLUSIONS Carbapenem resistance in outbreak-related isolates was mediated by conversion of OXA-66 into OXA-82 and its subsequent overexpression. This further highlights the genome plasticity of A. baumannii, leading to carbapenem resistance.

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.