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E M Veringa

Publications and source records attributed to E M Veringa.

12 recordsLinked to original sources
PubMed1993

[Typing of methicillin-resistant Staphylococcus aureus strains for epidemiological studies using the polymerase chain reaction].

OBJECTIVE: To determine whether polymerase chain reaction (PCR) fingerprinting can be used to gain insight into the epidemiology of methicillin resistant Staphylococcus aureus (MRSA). DESIGN: Retrospective DNA analysis of MRSA strains. BACTERIAL STRAINS: MRSA strains were collected in two Dutch and one Belgian hospital (Reinier de Graaf Gasthuis, Delft; St. Antonius Ziekenhuis, Nieuwegein; St. Jan Ziekenhuis, Brugge). METHODOLOGY: MRSA DNA was isolated by standard procedures. Differences in genomic organisation were detected with the aid of exponential enzymatic synthesis of intrinsically variable DNA domains. This so-called PCR fingerprinting, a relatively new technique, was performed in direct comparison with phage typing. The latter is the current golden standard for S. aureus typing. RESULTS: The results of both PCR fingerprinting and phage typing appeared to be useful for strain identification. All results were consistent with other epidemiological data. CONCLUSION: Genotyping MRSA with PCR fingerprinting is complementary to phage typing. In some instances PCR fingerprinting is even to be preferred to the other technique. PCR fingerprinting is well suited for the analysis of MRSA spreading.

Aged↗
PubMed1992

Bacteroides and Staphylococcus glycocalyx: chemical analysis, and the effects on chemiluminescence and chemotaxis of human polymorphonuclear leucocytes.

Glycocalyx (or slime), which is an important virulence factor of many pathogenic bacteria, was isolated from Bacteroides fragilis, Bacteroides thetaiotaomicron and Staphylococcus epidermidis. Organisms were grown for 24 h in a chemically defined, dialysable liquid medium. Bacteria were centrifuged and the supernatant was concentrated and dialysed against distilled water. Total carbohydrate and protein were estimated using standard methods. Thin layer and gas-liquid chromatography of trifluoro acetic acid hydrolysed and non-hydrolysed samples provided evidence for the presence of polysaccharide, the absence of nucleic acids and lipopolysaccharide and for the identification of the individual sugar residues. Glucose, mannose and galactose (B. fragilis), glucose (B. thetaiotaomicron), and glucose and heptose (S. epidermidis) were the sugar residues detected. Uronic acid and hexosamine were detected in all species. Glycocalyx preparations (1 mg/ml) from Bacteroides and Staphylococcus significantly inhibited the chemiluminescence and chemotactic responses of viable human polymorphonuclear leucocytes (PMNL), but were not toxic for PMNL.

Bacteroides↗
PubMed1991

[2 newborn infants with septicemia caused by multiresistant Streptococcus mitis].

Multiresistant viridans streptococci had not yet been encountered in the Netherlands. In the spring of 1990 we isolated multiresistant S. mitis from blood of two Dutch neonates (minimal inhibitory concentration of penicillin 64 mg/l). In both patients septicaemia developed while they were being treated with beta-lactam antibiotics. Although viridans streptococci usually are extremely sensitive to penicillin and other beta-lactams, the possibility of development of (multi-)resistance in these microorganisms during antibiotic treatment should be kept in mind.

Drug Resistance, Microbial↗
PubMed1989

Trospectomycin enhances surface phagocytosis of Bacteroides and Staphylococcus by altering the bacterial glycocalyx.

The influence of trospectomycin on phagocytosis of Bacteriodes thetaiotaomicron, Bacteroides fragilis and Staphylococcus epidermidis was studied in the presence or absence of glycocalyx isolated from these microorganisms. Bacteria were grown with or without 0.25 or 0.5 of the minimal inhibitory concentration (MIC) of trospectomycin, a new chemically synthesized analog of spectinomycin. Surface phagocytosis by human polymorphonuclear leukocytes (PMNL) was determined using a modified fluorochrome assay. Subinhibitory concentrations of trospectomycin significantly enhanced surface phagocytosis of Bacteroides and Staphylococcus. When homologous or heterologous isolated glycocalyx was added to trospectomycin treated bacteria prior to incubation with PMNL, phagocytosis was reduced to levels observed in the untreated bacteria. Addition of glycocalyx to untreated strains produced no significant reduction of phagocytosis. The glycocalyx preparations were free of lipopolysaccharide and did not affect PMNL viability.

Anti-Bacterial Agents↗
PubMed1989

Enhancement of opsonophagocytosis of Bacteroides spp. by clindamycin in subinhibitory concentrations.

Radioactively labelled bacteria were incubated overnight in the presence or absence of one-half the MIC of clindamycin, then preopsonized with normal human serum or homologous rabbit antiserum and incubated with human polymorphonuclear leucocytes. Clindamycin in subinhibitory concentrations significantly enhanced the phagocytosis of all four Bacteroides strains. Complement-dependent as well as antibody-dependent phagocytosis was enhanced by clindamycin in one Bacteroides strain. In the other three strains, only antibody dependent phagocytosis was enhanced by clindamycin. Transmission electron microscopy confirmed phagocytosis of the bacteroides.

Antibodies, Bacterial↗
PubMed1989

The role of glycocalyx in surface phagocytosis of Bacteroides spp., in the presence and absence of clindamycin.

The influence of isolated glycocalyx from Bacteroides thetaiotaomicron and B. fragilis on surface phagocytosis of clindamycin-treated and -untreated homologous and heterologous species was studied. When homologous or heterologous isolated glycocalyx was added to clindamycin-treated B. thetaiotaomicron or B. fragilis before incubation with PMNL, phagocytosis was reduced to levels observed in the untreated control bacteria, but addition of glycocalyx to untreated control strains showed no reduction of phagocytosis. When isolated bacteroides-glycocalyx was added to Staphylococcus aureus or S. epidermidis, phagocytosis of both clindamycin-treated and -untreated bacteria was significantly reduced. The isolated glycocalyx preparations were analysed by thin layer and gas-liquid chromatography; these preparations were free of lipopolysaccharides. The isolated glycocalyx did not affect PMNL viability. Our findings suggest that the glycocalyx is an important virulence factor because it impairs phagocytosis of Bacteroides spp. by PMNL. Clindamycin may enhance opsonophagocytosis of bacteroides by altering the glycocalyx.

Bacteroides↗
PubMed1987

Clindamycin at subinhibitory concentrations enhances antibody- and complement-dependent phagocytosis by human polymorphonuclear leukocytes of Staphylococcus aureus.

The influence of subinhibitory concentrations of clindamycin on opsonization and phagocytosis of Staphylococcus aureus was studied. S. aureus was grown overnight in the presence or absence of one half or one quarter of the minimal inhibitory concentration (MIC) of clindamycin. Radioactively labeled S. aureus was opsonized for various periods of time in different concentrations of normal serum, heated antiserum and serum of patients with agammaglobulinaemia or C3 deficiency. Complement- as well as antibody-dependent phagocytosis of the antibiotic treated S. aureus was significantly enhanced, compared to phagocytosis of the untreated control. Killing experiments showed that clindamycin-treated S. aureus was also better killed by the granulocytes than untreated S. aureus. The mechanism of action is likely to be an increased susceptibility of clindamycin-treated bacteria to antibody- and complement-dependent phagocytosis.

Agammaglobulinemia↗
PubMed1984

Biological inactivation by faeces of antimicrobial drugs applicable in selective decontamination of the digestive tract.

The in-vitro inactivation of seven antimicrobial drugs by human faecal substance has been investigated. Nalidixic acid, colistin, neomycin, tobramycin, temocillin, trimethoprim, and aztreonam were separately mixed in graded concentrations with faecal suspensions prepared from faeces of eight healthy volunteers. Each was mixed separately with a sample of each of the eight suspensions. All seven antimicrobial drugs appeared to be rapidly biologically inactivated by intestinal contents in a dose-dependent fashion, although not all to the same extent. The results may explain why with some unabsorbed or minimally absorbed drugs higher oral doses are required to achieve eradication of Gram-negative bacilli from the digestive tract than others, when selective decontamination (SD) is attempted in clinical practice.

Adult↗
PubMedDate not supplied

Role of antibodies and antibiotics in aerobic gram-negative septicemia: possible synergism between antimicrobial treatment and immunotherapy.

Recovery from gram-negative septicemia depends on the successful joint action of antibiotics and host defense mechanisms. The possible enhancement of host defense with either immunotherapy or antibiotic treatment has been the subject of numerous investigations. Because of the great similarity of core epitopes within different species of Enterobacteriaceae, most studies have focused on the development of cross-reactive and/or cross-protective antibodies to these common epitopes. The majority of strains that cause severe gram-negative septicemia, however, possess a complete O antigen (and often a K antigen) that may camouflage the common antigenic determinants. Antibodies to these common antigens therefore may be unable to recognize their targets. Subinhibitory concentrations of certain antibiotics have been shown to alter surface structures of Enterobacteriaceae to such an extent that the structures no longer camouflage underlying epitopes, allowing binding of cross-reactive or cross-protective antibodies to these epitopes. Thus antibiotics and antibodies may synergistically fight infection.

Animals↗