Biomedical subjects
Publications and source records attributed to J Sirot.
Two cases of documented osteoarticular infections caused by Kingella kingae in children are reported. The main bacteriological characteristics and antibiotic susceptibilities of these two isolates are described. The pathology of K. kingae, particularly in bones and joints, is reviewed.
The hundred and ninety-two combinations were tested against 17 strains chosen from the results of MIC determination (disc method): 5 enterococci exhibiting low level resistance (r) or high level resistance (R) to streptomycin (S) and gentamicin (G): 2 strains Sr Gr, 2 strains SR Gr and 1 strain Sr GR; 12 enterobacteria chosen for their resistance phenotypes to beta-lactams and aminoglycosides and because they are the most frequent clinical isolates: 2 strains Amos Tics Ctns (group 1), 4 strains AmoR Tics CtnR (gr. II), 4 strains AmoR TicR Ctns (gr. III) and 2 strains AmoR TicR CtnR (gr. IV). MIC and MBC were assessed for the 17 strains (Mueller Hinton broth). Combinations were carried out by a checkerboard micromethod. FBC index was calculated for each combination. Against enterococci the 50 combinations were: piperacillin versus ampicillin + aminoglycosides (streptomycin, tobramycin, amikacin, gentamicin, netilmicin). Against enterobacteria piperacillin was combined with different aminoglycosides depending on their resistance phenotypes. These combinations were compared with ticarcillin or mezlocillin or cefotaxime + aminoglycosides (total number 142). The species studied produced different results: with the enterococci Gr synergistic effects (FBC = 0.62-0.75) were rare; additive and indifferent effects were predominant. With the GR strain some antagonistic effects were observed. With the enterobacteria, in groups I and II synergistic effects were frequent and almost equivalent regardless of the beta-lactam chosen. In groups III and IV (TicR) piperacillin MICs were greater than or equal to 128 mg/l and mezlocillin MICs greater than 512 mg/l; the synergistic effects were significant (FBC from 0.25 to 0.62). beta-lactam + amikacin or netilmicin, and especially piperacillin + amikacin, were found to have the most frequent synergistic effects upon the strains tested. Mezlocillin combinations cannot be used clinically; the use of piperacillin combinations requires further discussion. On the other hand, cefotaxime + aminoglycosides combinations are active against those TicR strains.
The in-vitro antibacterial activity of Timentin has been evaluated with a view to proposing valid criteria for sensitivity and resistance. Minimal inhibitory concentrations (MIC) were determined for 284 strains including Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter spp., staphylococci and enterococci. The same strains were also used for the determination of inhibition zones around discs containing 75 micrograms ticarcillin and 10 micrograms clavulanic acid, and a straight regression line was drawn correlating MIC with inhibition zones. The bacterial population was subsequently grouped according to the diameters of inhibition zones of the antibiogram for 2427 strains of Enterobacteriaceae classified by phenotypes. The comparison of MICs of Timentin and ticarcillin for these strains shows that for penicillinase-producing strains, the Timentin MIC is lower than for ticarcillin whereas cephalosporinase-producing strains have equal MICs for the two. Finally strains that produce many different beta-lactamases are not affected by the presence of clavulanic acid. These results should make it possible to propose provisional zone diameters for determining sensitivity and resistance to Timentin.
Phenotypes of susceptibility to amoxycillin (Amo), ticarcillin (Tic), cephalothin (Ctn) were determined in 1366 isolates of Enterobacteriaceae by disk method and beta-lactamases were identified in 243 strains belonging to different phenotypes of amoxycillin-resistant strains. AmoR TicR CtnS strains (25%) were penicillinase producers and all of them were susceptible to the combination amoxycillin/clavulanic acid (Amo/CA) and ticarcillin/clavulanic acid (Tic/CA). Amo1/R TicS CtnR strains (12%) were cephalosporinase producers and resistance to Amo/CA was observed, except for Proteus vulgaris. AmoR TicR CtnR strains (18%) often produced two beta-lactamases (penicillinase and cephalosporinase) and they were resistant to Amo/CA; in this group, susceptibility to Tic/CA depends on the nature and the amount of the beta-lactamase produced, except for Serratia marcescens for which antibiotic resistance is probably due to other mechanisms. Tic/CA resistance was mainly found in Serratia marcescens (41%) and Enterobacter cloacae (36%).
Antimicrobial activity of cefonicid, a new second generation cephalosporin, against 315 hospital isolates (4th trimester 1984) was investigated. E. coli and Proteus mirabilis were the most susceptible species. All E. coli strains except one were inhibited at 8 mg/l (modal MIC: 0.5); MICs of all indole + Proteus were 8 mg/l (modal MIC: 0.06). Another group was moderately susceptible: MICs of Klebsiella and Citrobacter ranged from 0.12 to 128 mg/l, but MICs of 50% of these strains were less than or equal to 4 mg/l; MIC was less than or equal to 8 mg/l for 75% of indole + Proteus and Providencia strains; tested Proteus vulgaris were especially resistant (MICs greater than 128 mg/l). Most Enterobacter and Serratia strains showed little susceptibility (modal MIC for both species greater than or equal to 128 mg/l). MICs of all tested Pseudomonas aeruginosa strains were greater than 128 mg/l. 20 of the 24 tested Acinetobacter strains had a MIC of greater than or equal to 128 mg/l. For Staphylococcus aureus, 88% of methicillin-sensitive strains were inhibited by concentrations of 2 to 4 mg/l whereas methicillin-resistant strains were resistant to cefonicid (75%: MIC greater than 64 mg/l). Enterococci were resistant to cefonicid. A correlation curve was established (Enterobacteria and Staphylococci). On the basis of cefonicid's pharmacokinetic characteristics, critical concentrations are proposed.
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Ceftriaxone diffusion into spongious and cortical bone after single 2 g dose by intravenous injection was studied in 40 patients undergoing total hip replacement. Serum and tissue assays were performed by HPLC and microbiological method 2, 4, 12 and 24 hours after administration. Both methods produced similar results. Antibiotic levels (HPLC) were 19.3 +/- 7.3; 16.9 +/- 9.2; 11.2 +/- 4.7 and 5.6 +/- 2.7 micrograms/g in spongious bone at hours 2, 4, 12 and 24, and 6.5 +/- 1.6; 3.1 +/- 0.7; 3.3 +/- 1.1 and 2.2 +/- 0.4 micrograms/g in cortical bone at the same times. The tissue/serum ratios were 14% for spongious bone and 5% for cortical bone after 2 hours. At hour 24 these ratios were 21% and 8% in spongious and cortical bone respectively. These tissue levels remain higher than ceftriaxone MIC for most Enterobacteriaceae strains until hour 24.
Apart from the rarity of the causal agent, this case is of interest because of the absence of cervico-facial involvement and the presence of multiple cutaneous nodules at a distance from the visceral localisation.
We report the result of the bacteriological samples performed for 5 years (1980-1984) in neonates, referred to the neonate unit of the hospital of Clermont-Ferrand, for infection (2,894 infants). The CSF tests show aseptic meningitis in 4% of the cases and in 0.4% meningitis with bacteria on the direct examination and in culture. We emphasize the interest of carrying out the soluble bacterial antigen assay (Strepto B, Coli K1) to find out the bacteria involved in the meningitis. 13.7% of the infants have one or several positive blood culture. The germ is a E. Coli in 30% of the cases, and less frequently a streptococcus D. They are few listeria. In 1984, the frequency of streptococcus B is increasing. Septicemia due to anaerobic germs or Candida Albicans emerge during the stay in the unit. Among 12,704 bacteriological urine analysis, we compare the real urinary infections (in which the enterobacteria are the main strain: 75.3%) and the significant bacteriuria.
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The authors report three observations of osseous and/or articular actinomycosis. Osseous localizations, always in contact with abscessed foci of the soft tissues, included the spine and one or several limbs. In one case there was an arthritis of the knee. Culture and typing of the responsible germ: Actinomyces meyeri, were obtained from infectious foci in the three cases. The authors insist on the rare occurrence, at the moment, of osteo-articular actinomycoses outside the maxillo-facial area. Actinomyces meyeri has exceptionally been implicated. The prognosis of osteo-arthritis is similar to that of other localizations. It is usually favorable due to the great sensitivity of the germs to antibiotics, especially penicillin.
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Sperm examination, quantitative sperm culture, citric acid, acid phosphatase, and fructose were assayed in three groups of men: fertile controls without significant bacteriospermia (group I), infertile men with significant bacteriospermia; idiopathic infertile men (group II), and infertile men with varicocele (group III). Level of significance of bacteriospermia was greater than or equal to 10(4) germs/ml of ejaculate. In group II, motility and typical morphology percentages were lower, independently of the degree and the nature of bacteriospermia. Incidence of pathogenic bacteria was higher than in group III and linked to the degree of bacteriospermia. Fructose was unaltered in the two groups of infected men. No modification of prostatic markers was observed in any groups, except in group II, where they decreased when bacteriospermia was lower than 10(5) germs/ml and when biological pattern of semen evoked chronic prostatitis. Thus, the presence of germs in ejaculate alters the motility and the typical morphology percentages but does not result in any obvious modifications of biochemical markers of prostate and seminal vesicles. For idiopathic infertile men, it is suggested that the quantitative criterion of pathogenic bacteriospermia is a germ count greater than or equal to 10(5)/ml.
Antimicrobial activity of ceftriaxone, a new third generation cephalosporin, against hospital isolates was investigated. 312 strains belonging to the most commonly recovered species were studied using the following methods: agar diffusion (disk antibiotic testing), agar dilution (determination of MIC) and dilution in a liquid medium with subculture to agar plates (determination of MBC). Except for a few Citrobacter strains and rare Serratia strains, all Enterobacteriaceae tested proved highly susceptible, with MICs less than or equal to 1 mg/l and mode MICs ranging from 0.003 mg/l (Proteus) to 0.25 mg/l (Enterobacter). MICs ranged from 16 to 32 mg/l for Acinetobacter (mode MICs: 16 mg/l) and 16 to greater than or equal to 128 for Pseudomonas (mode MIC greater than or equal to 128 mg/l). Methicillin-susceptible staphylococci were moderately susceptible to ceftriaxone (MIC: 2 to 8 mg/l) whereas methicillin-resistant staphylococci and enterococci were resistant (MIC greater than or equal to 64 mg/l). Bactericidal activity was excellent: MBC/MIC less than or equal to 2 (except for a few Serratia strains). A correlation curve was established. Given the high serum concentrations of ceftriaxone (achieved with the usual maximal dosage) and its unusually extended half-life (7 to 8 h), the following cutoff concentrations can be proposed: C less than or equal to 4 mg/l, corresponding to greater than or equal to 20 mm: susceptible bacteria C greater than 32 mg/l, corresponding to less than 15 mm: resistant bacteria.
Rifampicin is a suitable drug for treating staphylococcal bone and articular infections, because high levels are obtained in the human tissues. The best oral dose is 600 mg 12 hourly. The serum levels range from 10 to 15 mg/l at the peak concentration and from 0.2 to 0.6 mg/l 8 h after oral administration of 600 mg. The ratio for cancellous bone/serum is 0.41 at 3 h and 0.39 at 12 h, and for cortical bone/serum is 0.20 at 3 h after a dose of 600 mg. In every case, tissue levels paralleled serum levels; cancellous bone levels are greater than the MIC of Staphylococcus aureus strains until 12 h after a dose of 600 mg. Rifampicin is always used in combination with another antibacterial substance. Results are excellent in most cases. The average duration of antibiotic treatment is 3 months for osteo-arthritis, 6 months for spondylitis and osteitis.
Different high performance liquid chromatography (HPLC) methods for determination of cefotaxime (Ctx) and desacetyl cefotaxime (D-Ctx) are used. The method described presents the following advantages: a fast extraction and efficient deproteinization of serum samples are achieved with Sep-Pak cartridges; the mobile phase is a mixture of methanol - bidistilled water - acetic acid which permits the simultaneous dosage of Ctx and D-Ctx under the same chromatographic process. The retention times are respectively 7 mn 05 s and 10 mn 40 s for D-Ctx and Ctx. The results of 92 assays were compared with microbiological procedures.
Urinary tract infections in the elderly are severe and intractable, often justifying the use of aminoglycosides. We studied the effects of dibekacin in 28 patients, with no vesical catheter, whose average age was 78 +/- 6.1 years. The drug was given for ten days, in an average dose of 2.1 mg/kg/day divided into two injections. Serum concentration was measured after one hour on day 1 and after eight hours on days 1 and 10. Causative pathogens, all susceptible to dibekacin, were: 18 E. coli, 3 Proteus mirabilis, 3 Klebsiella, 1 Enterobacter cloacae, 1 Citrobacter and 2 Staphylococci. MIC and MBC of dibekacin were determined for each microorganism. Dibekacin was discontinued in four cases on day three because of persistent bacteriuria. Ten days after treatment end, 19 patients were cured, 4 had a relapse and 1 was reinfected. Average serum concentration of dibekacin, measured after eight hours, increased from 0.77 +/- 0.48 micrograms/ml on day 1 to 1.78 +/- 1.22 microgram/ml on day 10 (t = 4.42; p less than 0.0005), while, over the same period, there was no significant change in serum creatinine.
The importance of the part played by Chlamydia trachomatis in male genital infections has only become apparent in recent years. In man, this bacteria is the main agent responsible for non-gonococcal urethritis and for at least 30% of the cases of acute epididymitis in adults. Although bacteriologically difficult, its identification is of great practical use, because of the hypersensitiveness of Chlamydia to tetracyclines.