Capsular types and antibiotic susceptibility of pneumococci isolated from patients in Belgium with serious infections, 1980-1993.

During the 13-year period from 1 November 1980 to 31 January 1993, we received and serotyped a total of 5,619 clinically significant strains of Streptococcus pneumoniae isolated in more than 75 laboratories in Belgium (4,079 [72.6%] were from blood or pleural fluid, 462 [8.2%] were from cerebrospinal fluid, 691 [12.

The effect of clindamycin gel insert in periodontal pockets, as observed on smears and cultures.

This study is aimed at the evaluation of a 1% clindamycin hydrochloride containing gel on the microbial flora of periodontal pockets deeper than 5 mm. In order to achieve that purpose, 20 patients with pocketing in the premolar-molar regions were selected. Active and placebo gel were inserted once during the first 2 weeks of this experimental study.

[Trends in pneumococcal infections in Belgium from 1986 to 1991].

Streptococcus pneumoniae is one of the most frequent causes of pneumonia, meningitis, and otitis media. Persons at high risk are young children, elderly, and individuals with immunodeficiency or with an underlying disease. Thanks to a network ot 111 laboratories spread all over Belgium, the evolution of the number of deep isolates of S.

Susceptibility of anaerobic microorganisms to hypothiocyanite produced by lactoperoxidase.

The susceptibility of Capnocytophaga ochracea, Eikenella corrodens, Eubacterium yurii, Fusobacterium nucleatum, Peptostreptococcus micros, Prevotella intermedia, Selenomonas sputigena, Wolinella recta to hypothiocyanite (OSCN-) produced by the lactoperoxidase system was tested. Results showed a decrease of bacterial survival rate after OSCN- exposure, with an intra- and inter-species variability from 0 to 95% for C. ochracea, 34-100% for E.

Killing rate and growth rate comparison for newer beta-lactamase-stable oral beta-lactams against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis.

A new method of data presentation that takes into account the relationship between growth and killing rate was used to evaluate the comparative in vitro bactericidal activity of cefpodoxime, cefuroxime, cefixime and an amoxicillin/clavulanic acid combination against Streptococcus pneumoniae and beta-lactamase-producing strains of Haemophilus influenzae and Moraxella catarrhalis. For each strain, the viable count decrease (log CFU/ml) after 6 h of exposure to different antibiotic concentrations was plotted against the viable count increase in the control culture, over the same time. Higher killing rates than those predicted by growth rates were defined as a positive balance; lower rates than those predicted by growth rates were defined as a negative balance.

Comparative kill and growth rates determined with cefdinir and cefaclor and with Streptococcus pneumoniae and beta-lactamase-producing Haemophilus influenzae.

The relationship between the growth rate and the kill rate was used to evaluate and to compare the in vitro bactericidal activities of cefdinir, a new oral cephalosporin, and cefaclor against Streptococcus pneumoniae and beta-lactamase-producing strains of Haemophilus influenzae. These frequently encountered pathogens of community-acquired respiratory tract infections are usually susceptible to both drugs. The MIC ranges for cefdinir and cefaclor were, respectively, 0.

[Is there in Belgium an increase in resistance to the combination amoxicillin/clavulanic acid of Escherichia coli as reference bacteria?].

The difficulties encountered in measuring the susceptibility of the association amoxicillin/clavulanate can be a cause for disagreements between laboratories. With an inoculum standardized at 10(4) CFU/spot, the resistance level of E. coli approaches 10%.

Evaluation of the E test for quantitative antimicrobial susceptibility testing of Helicobacter pylori.

The Progressive Diagnostics Manufacturers epsilometer test (E test; AB Biodisk, Solna, Sweden), a quantitative variant of the disk diffusion technique, was evaluated comparatively to an agar dilution method for the antimicrobial susceptibility testing of Helicobacter pylori. A collection of 79 H. pylori clinical strains, including isolates with known resistance to various antimicrobial agents, was tested against 12 different antimicrobial agents.

A sentinel network of microbiological laboratories as a tool for surveillance of infectious diseases in Belgium.

In the development of a surveillance programme for infectious diseases in Belgium, a national network of microbiological laboratories has been responsible, since February 1983, for the weekly registration of certain pathogenic agents. Thus, the main epidemiological features of a selected number of infections in Belgium can be characterized.

Gas-liquid chromatographic analysis of cellular fatty acid methyl esters in Aeromonas species.

The cellular fatty acids of 39 strains belonging to the genus Aeromonas (Aeromonas hydrophila, Aeromonas caviae, Aeromonas sobria, Aeromonas media, Aeromonas schubertii, Aeromonas veronii) were determined by high resolution gas-liquid chromatography. The fatty acid profiles were characterized by major amounts (60% or more) of one saturated (hexadecanoic acid = 16:0) and two unsaturated (hexadecenoic acid = 16:1 and octadecenoic acid = 18:1) acids. While the majority of the strains of the six species exhibited, qualitatively, very similar fatty acid compositions, only minor and inconsistent differences could be observed which would be useful for a distinction of the different taxons.

Cellular fatty acid composition of Acinetobacter strains.

The cellular fatty acids of the different biotypes of Acinetobacter calcoaceticus were determined by high resolution gas-liquid chromatography. While all strains exhibited, qualitatively, similar fatty acid compositions, quantitative differences were observed in strains belonging to defined phenotypic subgroups which can be used for differentiation.

Antibacterial effects of meropenem and imipenem against Haemophilus influenzae.

Phase contrast microscopy, killing curves and turbidimetric growth curves were used in a comparative study of the antibacterial effects of imipenem and meropenem on Haemophilus influenzae. The minimal inhibitory concentrations (MICs) and their ranges of meropenem and imipenem using five beta-lactamase-producing strains of H. influenzae were 0.

Antibacterial effect of meropenem and imipenem on Proteus mirabilis.

Phase-contrast microscopy, killing-curves and turbidimetric growth-curves were used in a comparative study of the antibacterial effects of a new carbapenem, meropenem (SM 7338) and imipenem on five strains of Proteus mirabilis. Despite the low MIC (0.2 mg/l) of imipenem for the five strains included in our study, the MBC remained relatively high (4.

Capsular types and antibiotic sensitivity of pneumococci isolated from patients with serious infections in Belgium 1980 to 1988.

A total of 2,765 strains of Streptococcus pneumoniae isolated in more than 60 Belgian laboratories from blood or normally sterile body fluids between 1 November 1980 and 31 December 1988 were serotyped. From January 1983 onwards susceptibility of the strains to antimicrobial agents was also tested. The 2,765 isolates belonged to 57 of the 84 currently identified serotypes.

Inoculum effect on growth-delay time of oxacillin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis exposed to cefamandole, cefazolin, and cefuroxime.

Cephalosporins have been recommended as prophylactic antibiotics in patients undergoing cardiovascular surgery. The major function of these antibiotics is to protect patients against Staphylococcus aureus and Staphylococcus epidermidis infections. The lowest inoculum amount responsible for infection during surgery is unknown but is probably low.

Turbidimetric and microscopic analysis of Bacteroides fragilis exposed to tazobactam and piperacillin alone and in combination.

Tazobactam, a non-amino penicillanic acid sulfone, is a new beta-lactamase inhibitor and acts synergistically with piperacillin against clinical isolates of beta-lactamase-producing Bacteroides fragilis. The effectiveness of this inhibitor has been demonstrated by reduction of piperacillin MIC values and growth curves in two combinations (ratio 8:1 and 4:1). Tazobactam has an intrinsic activity against B.

One shot of high-dose amikacin: a working hypothesis.

Recent information suggests that single, large daily dosages of amikacin are less nephrotoxic. The killing rate of amikacin for Escherichia coli and Pseudomonas aeruginosa also suggests to put emphasis on a high peak value. A decrease of 3 log10 CFU/ml was observed for E.

Bactericidal activity of meropenem against Pseudomonas aeruginosa.

Ten strains of Pseudomonas aeruginosa that were susceptible to imipenem (MICs 2 mg/l) were exposed to a new parenteral carbapenem, meropenem (MIC 0.25 mg/l). Kinetic turbidometry showed that, as with other beta-lactam antibiotics, there was a prelytic increase in the culture OD following exposure to meropenem.

Growth Curve Patterns of Escherichia coli, Serratia marcescens, and Proteus vulgaris Submitted to Different Tigemonam Concentrations.

Five strains of Escherichia coli, Serratia marcescens, and Proteus vulgaris were exposed to a new monobactam, tigemonam, in comparison with aztreonam. The study, evaluated by kinetic turbidimetry, has shown that tigemonam exerts a prelytic increase in optical density (OD) similar to that of other beta-lactam antibiotics. The maximal value of the prelytic increase in OD was similar for the two study antibiotics at concentrations of 1, 2, 4, and 8 times the minimum inhibitory concentration, corresponding with filament formation.

Growth curve patterns of Escherichia coli, Serratia marcescens, and Proteus vulgaris submitted to different tigemonam concentrations.

Five strains of Escherichia coli, Serratia marcescens, and Proteus vulgaris were exposed to a new monobactam, tigemonam, in comparison with aztreonam. The study, evaluated by kinetic turbidimetry, has shown that tigemonam exerts a prelytic increase in optical density (OD) similar to that of other beta-lactam antibiotics. The maximal value of the prelytic increase in OD was similar for the two study antibiotics at concentrations of 1, 2, 4, and 8 times the minimum inhibitory concentration, corresponding with filament formation.

Correlation between the growth and killing curves of Escherichia coli in the presence of cefotetan or piperacillin.

Escherichia coli strains that were susceptible to multiple antibiotics were exposed to cefotetan and piperacillin. As with the majority of beta-lactam antibiotics, the growth curves showed an increase in optical density (OD) due to an increasing volume of cell-wall-deficient bacteria during the first hours before lysis. This increase in OD depended on the concentration of cefotetan and was less dependent on the concentration of piperacillin.

Correlation between growth curves and killing curves of Escherichia coli in the presence of fleroxacin and ampicillin.

Fleroxacin, a new long-acting quinolone, induces rapid killing and bacterial filamentation as do other quinolones. Ten strains of Escherichia coli were exposed comparatively to fleroxacin and ampicillin in order to determine the effect of sub- and supra-inhibitory concentrations of each of these two compounds on turbidimetric growth curves and viable counts. By comparing the maximal early increase in optical density (OD, PIOD) as colony-forming units per milliliter (CFU/ml) after 2 and 6 h of exposure to antibiotics, we observed a reduced number of CFU/ml in comparison with the control after the 2-hour exposure at 1/4 the minimum inhibition concentration (MIC) and after 6 h at 1/8 MIC, but a high OD value was also seen among the fleroxacin exposed bacteria.

Protective effect of amdinocillin against emergence of resistance to ceftazidime in Enterobacter cloacae.

Enterobacter cloacae infections have been shown clinically to respond less reliably to monotherapy with broad-spectrum cephalosporins than was initially expected. Selection of populations producing high levels of beta-lactamase has been shown to be the most frequent reason for treatment failure, and the use of these agents with another active antibiotic is recommended. In this study, E.