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R Bismuth

Publications and source records attributed to R Bismuth.

At least 19 recordsLinked to original sources
PubMed2005

Risk factors for neurosurgical site infections after craniotomy: a critical reappraisal of antibiotic prophylaxis on 4,578 patients.

The objective of this study was to evaluate incidence and risk factors of postoperative infections, with emphasis on antibiotic prophylaxis, in a series of 4578 craniotomies. A prospective database was implemented for surveillance of postcraniotomy infections. During period A, no antibiotic prophylaxis was prescribed for scheduled, clean craniotomies, lasting less than 4 h, whereas emergency, clean-contaminated or long-lasting craniotomies received cloxacillin or amoxicillin-clavulanate. During period B, prophylaxis was given to every craniotomy. The effect of prophylaxis on craniotomy infections, independently of other risk factors, was studied by multivariate analysis. The overall infection rate was 6.6%. CSF leak, male gender, surgical diagnosis, surgeon, early re-operation, surgical duration and absence of prophylaxis were independent risk factors. CSF leak had the highest odds ratio. Antibiotic prophylaxis decreased infection rate from 9.7% down to 5.8% in the entire population (p<0.0001) mainly by decreasing rates in low risk patients from 10.0% down to 4.6% (p<0.0001). Antibiotic prophylaxis in craniotomy is effective in preventing surgical site infections even in low-risk patients.

Adult↗
PubMed2002

Empirical treatment of adult postsurgical nosocomial meningitis.

BACKGROUND: The combination of cefotaxime and fosfomycin (CTX-FOS) has been proposed in France for the empirical treatment of postoperative nosocomial meningitis since the late 1980s. The purpose of this work was to evaluate this strategy today, as well as other possible treatments. METHODS: Each patient undergoing a neurosurgical procedure was prospectively included in a database designed for the surveillance of surgical site infection (SSI). For each meningitis detected, we analysed the in vitro susceptibility of the causative micro-organisms to cefotaxime alone (CTX), cefotaxime-fosfomycin (CTX-FOS), vancomycin (VAN) and cefotaxime-vancomycin (CTX-VAN) combinations. The patient population was divided into two groups according to the presence or absence of CSF shunting material. FINDINGS: 116 patients had had a postoperative meningitis/ventriculitis during the last 36 months, among 6447 patients undergoing neurosurgery in our department (1.8%). Ten patients had aseptic meningitis (8.6%). Overall sensitivity to CTX was 69.8%, as compared to 77.3% with CTX-FOS combination (NS). This result was due to a large proportion of fosfomycin resistant cocci in our population. The CTX-VAN combination increased the overall in vitro susceptibility up to 91.5%, but the benefit of this combination was only significant in CSF shunting material patients. In these latter patients, VAN was as effective as CTX-FOS combination. INTERPRETATION: CTX-FOS combination is no longer the best choice for empirical treatment of post neurosurgical meningitis. CTX alone can be safely used in patients without a CSF shunt; in those with either a ventriculostomy or a CSF shunt associated ventriculitis, a CTX-VAN combination could improve treatment efficacy, provided that high doses of vancomycin are used to ensure correct CSF diffusion.

Adult↗
PubMed2002

Different aminoglycoside-resistant phenotypes in a rabbit Staphylococcus aureus endocarditis infection model.

The impact of different types of enzymatic resistance on the in vivo antibacterial activity of aminoglycosides (amikacin, gentamicin, and netilmicin) was studied in the rabbit endocarditis model with four strains of Staphylococcus aureus. Animals were treated in a manner simulating the administration of a single daily human dose. Amikacin had no effect on the three kanamycin-resistant strains despite apparent susceptibility in the disk diffusion test. Gentamicin appears to be the preferable aminoglycoside for treatment of staphylococcal infections.

Aminoglycosides↗
PubMed2000

In vitro activity of fusidic acid against streptococci isolated from skin and soft tissue infections.

The in vitro activity of fusidic acid was evaluated against 242 strains of streptococci isolated from skin and soft tissue infections during a prospective multicentre study. Nearly 90% of strains were isolated from dermatology, emergency and medicine units. Groups A, B, C and G streptococci represented, respectively, 41.9, 20.6, 4.4 and 27.8% of the strains. The activity of fusidic acid was dependent on the media used. MICs were generally one dilution lower with heart infusion agar than with Mueller-Hinton agar supplemented with 5% horse blood (MIC(90) for the whole streptococcal population = 8 mg/L and 16 mg/L, respectively). The distribution of MICs was unimodal and only two strains displayed MICs of fusidic acid >/= 64 mg/L. In both media, fusidic acid was moderately active against streptococci. However, antibiotic concentrations obtained in the skin exceed the MIC(90) of fusidic acid for streptococci, possibly explaining its clinical efficacy in the treatment of common cutaneous infections.

Anti-Bacterial Agents↗
PubMed1999

[Comparison of different techniques for the detection of heterogeneous resistance to methicillin in Staphylococcus aureus].

The methods for detection of methicillin resistant S. aureus (MRSA) can fail to detect resistance because phenotypic expression is often heterogeneous (40% of strains). Seventy four strains of S. aureus [4 methicillin susceptible strains, 10 homogeneous MRSA (Ro) and 60 heterogeneous MRSA (Rh)] were isolated from different french hospitals in Paris. These strains were tested by different methods: oxacillin screen plate with 6 micrograms/ml oxacillin and 4% NaCl, agar diffusion method with 5 micrograms oxacillin disk tested either at 30 degrees C on Mueller-Hinton medium or at 37 degrees C on Mueller-Hinton plus 5% NaCl, BBL Crystal MRSA ID system tested with two inocula (0.5 and 1 McFarland equivalent bacterial suspension) at 37 degrees C for 4 h and 5 h. Dot-blot hybridization was performed under stringent condition with the mecA probe. The accuracy of the different methods for the detection of methicillin resistance is equivalent, except for the BBL crystal system with a 0.5 McFarland inoculum wich detects the resistance with an accuracy of 86% for Ro strains and 69% for Rh strains. In other respects, there was a close correlation with the detection of the phenotypic resistance and the presence of mecA gene. So this study demonstrates that these various methods can be used for the detection of methicillin resistant S. aureus. For a rapid detection (below 5 h) the BBL crystal system with a 1 McFarland inoculum can be used; the agar diffusion method remains a good method provided some conditions (inoculum, incubation temperature, addition of salt, incubation period); the oxicillin screnn plate is a very attractive method for it is easy and reliable.

Anti-Bacterial Agents↗
PubMed1998

Characterization of gentamicin-susceptible strains of methicillin-resistant Staphylococcus aureus involved in nosocomial spread.

We report an outbreak of epidemic Staphylococcus aureus strains characterized by an unusual heterogeneous resistance to methicillin and resistance to tobramycin but susceptibility to gentamicin (gentamicin-susceptible methicillin-resistant S. aureus [GS-MRSA]), contrasting with gentamicin-resistant homogeneous MRSA (GR-MRSA) that have been endemic in our hospital since the 1970s. A total of 97 GS-MRSA strains, which were shown by DNA hybridization to carry the mecA and ant(4')-Ia genes, were studied. The 40 GS-MRSA strains isolated at the beginning of the outbreak (January 1992 to June 1993) were typed by using resistance patterns, phage typing, serotyping, and pulsed-field gel electrophoresis and were compared with GR-MRSA and methicillin-susceptible S. aureus (MSSA) strains isolated during the same period. Two dominant clones, A::1 and B::3, and one minor clone, C::5, were identified among the 40 GS-MRSA strains, according to pulsotypes (A to C) and their resistance patterns (1, 3, and 5), which were distinguishable from those of GR-MRSA and MSSA strains. A selection of 57 GS-MRSA strains, isolated from 1994 to 1996, were clustered in the same three clones. However, their distribution had changed in comparison with that in the 1992 to 1993 period: clone A::1 remained dominant (47 versus 42.5%), whereas clone B::3 progressively declined (5 versus 35%) and clone C::5, the most susceptible to antibiotics, spread (44 versus 2.5%). Epidemiological investigations revealed that some clones had been introduced via patients transferred from other hospitals and that cross-infection occurred within and between wards. Major changes in the use of antibiotics, especially aminoglycosides, cyclines, and macrolides, likely played a role in the emergence and spread of GS-MRSA strains.

Anti-Bacterial Agents↗
PubMed1992

New high-content disks for determination of high-level aminoglycoside resistance in clinical isolates of Enterococcus faecalis.

Disks impregnated with 500 and 1000 micrograms of streptomycin, 1000 micrograms of kanamycin and 250 and 500 micrograms of gentamicin were used for detection of high-level resistance to aminoglycosides in 120 clinical isolates of Enterococcus faecalis. Fifty-seven strains were highly resistant to streptomycin, 80 to kanamycin and 41 to gentamicin. Using disks containing 500 micrograms of streptomycin, 1000 micrograms of kanamycin and 500 micrograms of gentamicin strains resistant to high levels of these drugs (97.9%, 100% and 100%, respectively) were accurately detected. Better discrimination between high-level and low-level resistance was achieved with a 500 micrograms streptomycin or gentamicin disk. Zone-size breakpoints are proposed for detection of high-level resistance by disk diffusion.

Drug Resistance, Microbial↗
PubMed1990

Gene heterogeneity for tetracycline resistance in Staphylococcus spp.

Nucleotide sequences related to four tet genes were studied by hybridization in 183 clinical Staphylococcus isolates. tet(K) predominated in strains resistant only to tetracycline, while tet(M) was responsible for combined tetracycline and minocycline resistance. In strains harboring both genes, they contributed additively. tet(L) was detected in only five strains, and no hybridization was observed with tet(O).

DNA, Bacterial↗
PubMed1989

[In vitro antibacterial activity of a new macrolide, miokamycin. Results of a multicenter study].

Minimal inhibitory concentration (MIC) of miokamycin (M) were evaluated by agar dilution for 1,024 bacterial strains isolated in 6 hospitals and classed as a function of susceptibility and resistance to macrolides, lincosamides, streptogramins group (MLS). MIC of M ranged from 0.25 to 4 micrograms/ml (mode MIC 1-2) on Staphylococcus susceptible to MLS and on MLSB inducible strains; M was inactive on MLSB constitutive strains. MIC of M ranged from 0.016 to 4 micrograms/ml (mode MIC 0.12 to 0.5) for Streptococci and Pneumococci susceptible to erythromycin (E) and from 0.12 to greater than 128 for strains resistant to E. Enterococci susceptible to E were inhibited by 0.5 to 2 micrograms/ml (mode MIC 1) and strains resistant to E by 4 to greater than 128. Haemophilus were inhibited by 2 to 64 micrograms/ml (mode MIC 32), Neisseria by 0.12 to 4 (mode MIC 0.5-1) and B. catarrhalis by 0.12 to 8 (mode MIC 1). L. pneumophila was very susceptible to M: MIC 0.016 to 0.12 (mode MIC 0.06). MIC of M ranged generally from 0.5 to 2 micrograms/ml (mode MIC 1) for C. perfringens and from 0.03 to 2 (mode MIC 1) for B. fragilis. Thus, M was shown to be among macrolide antibiotics of resistance non-inducing type on MLSB inducible resistance strains. Its activity was similar to that of spiramycin slightly superior on Staphylococci, slightly inferior on Streptococci and Enterococci, similar on Pneumococci, very superior on Neisseria, Legionella and anaerobes. M had a good activity on Branhamella and, as others macrolides, was poorly active on Haemophilus.

Bacteria↗
PubMed1988

Non-radioactive gene probes for the detection of tetracycline and/or minocycline resistance in staphylococci.

This report describes the development of a non-radioactive gene probe for the characterization of tetracycline and/or minocycline resistant staphylococci. Both radio-labelled and non-radioactive gene probes yielded a better characterization of the strains than the determination of minimal inhibitory concentration (MIC). A 100% correlation was found between radioactive and non-radioactive hybridization tests. The latter technique detected genes present in a single copy per bacterial genome, could be performed in 8 h, avoided radioactive hazards and autoradiography delay, and appeared therefore to be a useful tool for clinical and epidemiological studies.

Animals↗
PubMed1986

[In vitro effect of piperacillin on aerobic bacteria. Variations according to the phenotypes of resistance to beta-lactam antibiotics].

In a first study the MICs of piperacillin (PIP), mezlocillin (MEZ), azlocillin (AZL), carbenicillin (CARB) and ticarcillin (TIC) against 563 strains of aerobic bacteria were compared. The MIC50 of PIP against E. coli and P. mirabilis was 0.5 to 1 mg/l, that is equal to those of MEZ and TIC but 2 or 3 times lower than those of AZL and CAR. The MIC50 of PIP and MEZ against Klebsiella, a species that is naturally resistant to TIC and CAR, was 4 mg/l. Enterobacter, Serratia and Citrobacter showed two populations of strains: the first was sensitive to the five penicillins tested (MIC50 of PIP: 1 to 2 mg/l); the second was resistant to all of them. PIP and AZL were more active (MIC50 8 mg/l) against Ps. aeruginosa than MEZ, TIC and CAR. All five penicillins had limited activity against Acinetobacter (MIC50 less than 16 mg/l). PIP, MEZ and AZL were more active than TIC and CAR against enterococci. In a second study, the activity of PIP was evaluated by standard sensitivity tests on 4993 strains of enterobacteria, Ps. aeruginosa and Acinetobacter classified according to their phenotype of resistance to beta-lactam antibiotics. PIP was regularly active against enterobacteria and Ps. aeruginosa strains devoid of acquired resistance. The activity of PIP was significantly reduced against enterobacteria strains with a phenotype suggesting induced penicillinase production. However, the inhibition zone diameters, although reduced, remained within what is now considered the sensitivity range (notably with E. coli and Proteus spp), which raises the problem of in vitro tests interpretation. PIP was active against E. coli strains with a "cephalosporinase" phenotype, but inactive against cefotaxime resistant strains of: Enterobacter, Citrobacter and Serratia. The activity of PIP on CAR-resistant Ps. aeruginosa strains was significantly reduced, but the inhibition zone diameter in one quarter of them was still within limits of sensitivity.

Azlocillin↗
PubMed1986

Conjugative transfer of staphylococcal antibiotic resistance markers in the absence of detectable plasmid DNA.

Eleven Staphylococcus aureus clinical isolates were tested for transfer of resistance markers by transduction and filter mating. The resistance markers of six of the strains could be transferred only by transduction; however, the five remaining strains transferred their resistance both by transduction and filter mating. The resistance markers that were cotransferred in filter matings (transfer of resistance to penicillin and streptogramin A was accompanied, in each case, by the transfer of one or more markers, i.e., resistance to aminoglycosides, cadmium, or tetracycline, depending on the donor) were not cotransduced. The filter mating transfers were recA independent and were observed with both Staphylococcus aureus and Staphylococcus epidermidis recipients. Experiments to elucidate the mechanism of transfer by filter mating suggested that conjugation requiring cell-to-cell contact may have been involved. These transfers occurred in the absence of detectable plasmid DNA.

Anti-Bacterial Agents↗
PubMed1984

Survey of the phenotypes of susceptibility to beta-lactams in Enterobacteriaceae at the Pitie-Salpetriere Hospital.

The phenotypes of susceptibility to ampicillin, carbenicillin, cephalothin, cefamandole, cefoxitin and cefotaxime were determined by the disc-diffusion method in 10,994 Enterobacteriaceae consecutively isolated from in-patients during 18 months. The susceptible phenotypes were much more frequent among Escherichia coli, Proteus mirabilis and Klebsiella (67.4 to 84.8%) than among Serratia, Enterobacter and Citrobacter (8.8 to 35.5%). In all species the most common resistance phenotypes were to ampicillin and carbenicillin: E. coli (28%), Pr. mirabilis (15.2%), Klebsiella (23.8%), indole-positive Proteus (33.3%), Serratia (74.4%), Enterobacter (61.4%) and Citrobacter (74.8%). Among E. coli 4.6% of the strains were resistant to ampicillin and cephalothin but susceptible to carbenicillin. Among E. coli, Pr. mirabilis and Klebsiella the strains susceptible only to cefotaxime represented 0.3 to 5% and no cefotaxime-resistant strain was isolated; whereas among Serratia, Enterobacter and Citrobacter the former represented 28.3 to 58.3% and the latter 7.5 to 18.5%. Some important differences in the distribution of the phenotypes according to the type of ward were observed.

Anti-Bacterial Agents↗
PubMed1984

[Comparison of serum and prostatic levels of tobramycin].

In 19 patients with various prostatic diseases, serum and prostatic tissue levels of tobramycin were determined by bioassay and enzyme immunoassay after 1, 3 or 4 intramuscular injections of 75 mg tobramycin. The last injection was given ninety minutes prior to prostatectomy. Mean serum and prostatic tissue levels were respectively 3.55 micrograms/ml and 1.70 micrograms/g by bioassay, and 3.55 micrograms/ml and 2.37 micrograms/g by enzyme immunoassay. There was no significant difference in prostatic tissue levels between patients who received 3 or 4 drug doses and those who received one dose. Prostatic tissue levels were not significantly different in adenoma and chronic prostatitis.

Biological Assay↗
PubMed1984

[Antibiotic sensitivity test. Comparative multicenter study of the gel diffusion and ATB methods].

The ATB method is a new method for antibiotic susceptibility testing. In a collaborative study, it was compared to a standard disc diffusion method. 23 strains were tested to determine reproducibility and 969 strains were used in the comparative study. Reproducibility of both methods is equivalent; differences due to strains were observed. Agreement between both methods is 87,9%, minor discrepancies are 8,7% and major discrepancies are 3,3%. Significant differences were found for carbenicillin and cefalotin and confirmed by MIC determination using the agar dilution method. Overall results show that the ATB method is reliable and comparable to disc diffusion for routine susceptibility testing.

Automation↗
PubMed1984

[Resistance to pristinamycin (or virginiamycin) of strains of Staphylococcus aureus].

Resistance to pristinamycin (or virginiamycin) was first encountered in Staphylococcus aureus strains in 1975. These strains are usually multiresistant, in particular to streptogramin A components (SgA), macrolides, lincosamides and streptogramin B components (ML SgB ). Results of molecular analysis of 16 such strains, recently isolated, suggests that SgA resistance is not encoded by plasmid genes. Curing and mixed culture experiments allowed us to dissociate SgA from SgB resistance genes. Conversely, in a previous study on other strains, the same two resistance genes were shown to be carried by a single plasmid and could not be dissociated. Since 1981, a new type of pristinamycin -resistant S. aureus strains has been isolated. These strains are resistant to SgA and lincosamides but susceptible to macrolides and SgB . Eight such strains from 3 parisian hospitals have been studied. In mixed culture experiments, SgA resistance and penicillinase genes always transferred jointly. In some instances, these two determinants also cotransferred with genes encoding lincomycin, lincomycin and clindamycin, and/or aminoglycosides resistance.

DNA, Bacterial↗
PubMed1984

[Sensitivity to fosfomycin of bacteria isolated at the Pitié-Salpétrière Hospital in 1982 and 1983].

Susceptibility of 16 056 strains isolated in 1982 and 1983 to fosfomycin (FOS) was tested with Mueller-Hinton medium and discs 50 micrograms FOS + 25 micrograms glucose-6-phosphate (G6P) (cutoff diameter 14 mm). For 3 411 strains, inhibition zone diameters were recorded. Almost all E. coli, Citrobacter, Salmonella and S. aureus were susceptible to FOS as well as 70% of Serratia, E. cloacae, P. mirabilis and 50% of Klebsiella and Enterobacter sp. Only 27% of P. aeruginosa, 20% of indole positive Proteus and 8% of Acinetobacter were sensitive to FOS. E. coli, Citrobacter and S. aureus seem to exhibit the highest susceptibilities to FOS. Sensitivity rates of E. cloacae, Serratia, P. aeruginosa, and especially Klebsiella seemed slightly underestimated by the disk diffusion method, but differentiation between susceptible and resistant strains was facilitated by rating as susceptible those strains with inhibition zone diameters between 12 and 14 mm. This method also seemed to underrate the sensitivity of susceptible Enterobacteriaceae, probably because of inadequate G6P concentrations at this point of the disk.

Acinetobacter↗