[Antibacterial activity of norfloxacin, ofloxacin and ciprofloxacin according to resistance phenotypes to nalidixic acid and pefloxacin]. / Activité antibactérienne de norfloxacine, ofloxacine et ciprofloxacine en fonction des phénotypes de résistance à l'acide nalidixique et à la péfloxacine.

In vitro antibacterial activity of 5 quinolones: nalidixic acid (NAL), pefloxacin (PEF), norfloxacin (NOR), ofloxacin (OFL) and ciprofloxacin (CIP) was evaluated by agar diffusion (disks Diagnostics Pasteur) for 1,253 bacterial strains (767 Enterobacteriaceae: E 164 P. aeruginosa: PA, 90 A. baumannii: AB and 232 S. aureus: SA) isolated during the last three months of 1988. Strains were ranged in susceptible (S) intermediate (I) and resistant (R) according to recommendations of Comité Français de l'Antibiogramme; in addition, activity of NOR, OFL and CIP was precised according to susceptibility to NAL and PEF. Frequencies of strains R + I observed for NAL, PEF, NOR, OFL and CIP were (%): E: 14.4; 13.4; 7.3; 7.6; 2.4 - PA: 100; 68.5; 18.4; 36.8; 8.9 - AB: 78.9; 57.8; 75.5; 54.4; 50 - SA: 100; 27.5; 28.9; 28.5; 28.7. For E and AB, analysis according to resistance phenotypes to NAL and PEF showed reduction of activity of NOR, OFL and CIP, on strains RI and particularly RR by comparison with strains SS and RS. Activity of PEF, NOR, OFL and CIP is similar on PA, belonging to RS and RR phenotypes. On RI strains, only CIP showed activity practically identical to that on RS strains. For SA, NOR, OFL and CIP were inactive on PEF R strains. Analysis of populations of strains according to resistance phenotypes to NAL and PEF permitted to show reduction of activity of other compounds on strains with an acquired resistance character to quinolones; currently, only test of PEF is presently sufficient for susceptibility testing of other fluoroquinolones (NOR, OFL and CIP) on E, AB and SA; however for PA, test of CIP is also necessary.

[In vitro antibacterial activity of RU 51746 (sodium salt of cefpodoxime). Results of a multicenter study]. / Activité antibactérienne in vitro du RU 51746 (sel de sodium du cefpodoxime). Résultats d'une étude multicentrique.

Cefpodoxime proxetil, a new oral cephalosporin, is the prodrug ester of cefpodoxime. Minimal inhibitory concentrations (MIC) of RU 51746 (sodium salt of cefpodoxime: CPD) were evaluated by agar dilution for 1 696 bacterial strains isolated in 5 hospitals. For Enterobacteriaceae, MIC 50 and 90% were respectively (micrograms/ml): (1) naturally non bêtalactamase producing species: E. coli, Shigella and Salmonella 0.25-0.5; P. mirabilis 0.06-0.12. (II) chromosomal penicillinase producing species: Klebsiella 0.12-1. (III) chromosomal cephalosporinase producing species: E. cloacae and C. freundii 2-greater than 128; S. marcescens 2-64; indole + Proteus 0.25-64; P. stuartii 0.25-16. Activity of CPD was not modified on plasmid mediated penicillinase producing strains, but CPD was inactive on cephalosporinase hyperproducing strains, and on broad spectrum bêtalactamases producing strains. CPD was inactive on P. aeruginosa (MIC greater than or equal to 64) and on A. baumannii (16-pi 128). Haemophilus, regardless on bêtalactamase production status, were very susceptible to CPD (MIC less than or equal to 0.25) and B. catarrhalis was generally inhibited by 0.12 to 1. CPD was poorly active on methicillin susceptible Staphylococci (MIC 50 and 90%: 2-4) and inactive on methicillin resistant strains. Enterococci and Listeria monocytogenes were generally resistant; Streptococci A, B, C, G and Pneumococci were inhibited by low concentration: 0.002 to 0.25 (MIC 50 and 90%: 0.016-0.032) whereas MIC for other Streptococci were 0.004 to 32 (MIC 50 and 90%: 0.25-4). These antibacterial properties placed CPD in excellent position among oral cephalosporins.

[In vitro antibacterial activity of lomefloxacin, a new fluoroquinolone, against hospital strains. Results of a multicenter study]. / Activité antibactérienne in vitro d'une nouvelle fluoroquinolone, la loméfloxacine, sur les bactéries hospitalières. Résultats d'une étude multicentrique.

Minimal inhibitory concentrations (MICs) of lomefloxacin (LOM) was determined by agar dilution for 2,819 bacterial strains isolated in 1988 in 9 university hospitals. Activity of LOM against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of pefloxacin (PEF) (mode MIC: 0.12-0.25 micrograms/ml); like for PEF, this activity was reduced against NAL resistant (R) Enterobacteriaceae (mode MIC: 4). MICs of LOM against P. aeruginosa were between 0.5 and 16 (mode: 2). LOM had also a good activity against NAL S A. baumannii (mode MIC: 0.5) but this activity is reduced against NAL R Acinetobacter (MICs : 4 to 128). LOM was highly active against Haemophilus (mode MIC: 0.06), Gonococci (mode MIC: 0.008), Meningococci (mode MIC: 0.03), Branhamella (mode MIC: 0.12-0.25). LOM showed activity similar to PEF against methicillin susceptible Staphylococci (mode MIC: 0.5-1); the resistant strains are usually methicillin resistant. Similar to the currently available quinolones, LOM is less effective against L. monocytogenes (mode MIC: 8), Enterococci (mode MIC: 4), Streptococci (mode MIC: 4) and Pneumococci (mode MIC: 8). Finally, for the anaerobic bacteria, LOM is more active against Clostridium perfringens (mode MIC: 1) than against Bacteroides fragilis (mode MIC: 32).

[In vitro antibacterial activity of rokitamycin, a new macrolide antibiotic. Results of a multicenter study]. / Activité antibactérienne in vitro d'un nouveau macrolide, la rokitamycine. Résultats d'une étude multicentrique.

Minimal inhibitory concentrations (MIC) of rokitamycin (R) were evaluated by agar dilution for 914 bacterial strain isolated in 4 hospitals and classed as a function of susceptibility and resistance to Macrolides-Lincosamides-Streptogramines group (MLS). MICs of R ranged from 0.06 to 1 microgram/ml (mode MIC 0.25-0.5) on Staphylococci susceptible to MLS and on MLSB inducible strains; R was inactive on MLSB constitutive strains. MICs of R ranged from 0.008 to 0.5 microgram/ml (mode MIC 0.06 to 0.25) for Streptococci and Pneumococci susceptible to erythromycin (E) and from 0.06 to greater than 128 for strains resistant to E. Enterococci susceptible to E were inhibited by 0.06 to 0.5 microgram/ml (mode MIC 0.5) and strains resistant to E by 0.25 to greater than 128. Haemophilus were inhibited by 0.5 to 0.65 microgram/ml (mode MICs of R ranged generally from 0.016 to 0.5 microgram/ml (mode MIC 0.12) for C. perfringens and from 0.016 to 1 (mode MIC 0.06) for B. fragilis. Thus, R was shown to be among macrolide antibiotics of resistance strains. Its activity was superior to that of other products of this group spiramycin, josamycin, miokamycin, particularly on Gram positive cocci. R had a good activity on Neisseria, Branhamella, anaerobes and, as others macrolides, was poorly active on Haemophilus.

[In vitro antibacterial activity of clarithromycin, a new macrolide antibiotic, and regression curve]. / Activité antibactérienne in vitro d'un nouveau macrolide, la clarithromycine, et courbe de concordance.

This study was set up to establish the regression curve for clarithromycin inhibition zone diameters (disks 15 micrograms) and MIC to create a strain distribution plot, in order to allow accurate interpretation of the disk diffusion method for testing susceptibility to clarithromycin. 430 bacterial strains were studied in three university hospital. Clarithromycin was active against erythromycin sensitive Staphylococcus aureus and coagulase negative Staphylococci at concentrations of 0.12 to 0.25 microgram/ml (mode 0.25). Erythromycin resistant strains were also resistant to clarithromycin. Enterococci could be divided into two populations, one resistant (MIC greater than 128 micrograms/ml) and the other with MIC of 0.06 to 2 (mode 0.25). This was also the case for Streptococci and Pneumococci with MIC lower for susceptible strains (mode 0.03 to 0.06). Clarithromycin was active on Haemophilus at concentrations of 4 to 64 micrograms/ml (mode 16); MICs for beta-lactamase producing strains were comparable to those of strains not producing. MICs for Neisseria were 0.12 to 16 and for B. catarrhalis 0.016 to 0.5. MIC were 0.5 and 1 (mode 1) for Clostridium perfringens; Bacteroides fragilis strains were inhibited by 0.12 to 8 micrograms/ml (mode 0.5-1). So, antibacterial activity of C was similar to that of E; it was sometimes slightly superior, particularly on Gram positive cocci. For MIC breakpoints of 1 and 4 micrograms/ml, zone size breakpoints should be 23 and 17 mm and for 2 and 8 micrograms/ml, 20 and 15 mm.

[Sensitivity to clavulanic acid of Escherichia coli isolated at the Henri Mondor hospital in 1986 according to phenotypes of beta-lactam antibiotic resistance]. / Sensibilité à l'acide clavulanique des Escherichia coli isolés à l'hôpital Henri Mondor en 1986 en fonction des phénotypes de résistance aux bêtalactamines.

Susceptibility to Augmentin (AUG) was studied as a function of resistance phenotypes toward amoxicillin (AMX), carbenicillin (CAR), cephalothin (CFT) and cefotaxime (CTX) for 1817 strains of Escherichia coli isolated at Henri-Mondor hospital during 1986. For strains susceptible to the 4 beta-lactams (phenotype SSSS: 66%), the median zone diameter observed with AUG was 26.4 mm. It was slightly inferior (22.1) for acquired - penicillinase producing strains (phenotype RRSS: 21.5%), but zone diameters were greater than or equal to 21 mm for over than 75% of these strains. Strains of phenotype RRIS (6%), probably high penicillinase-producers, were generally intermediate to AUG (median zone diameter: 17.8), showing partial inhibition of enzyme by clavulanic acid. Cephalosporinase hyperproducers mutants (phenotype RSRS: 4%) and strains with a RRRS phenotype (2.5%), probably penicillinase and cephalosporinase producers, were resistant to AUG (median zone diameters: 15.6 and 12.6 mm). Among rarely observed phenotypes, some were readily integrated to major phenotypes: RSIS, ISRS and ISIS to phenotype RSRS; RIRS to phenotype RRRS; IISS to phenotype RRSS; apparently "aberrants" phenotypes (ISSS, RSSS, SSIS, SSRS) required interpretation of results as a function of observed zone diameters and at time a verification of tests. This study confirms the in vitro activity of AUG on penicillinase producing E. coli; in addition simultaneous reading of zone diameters observed with AMX, CAR, CFT and CTX, permitted to infer the probable mechanism of resistance to beta-lactams and therefore to correct possible discrepancies observed in antibiogram results.

[In vitro antibacterial activity of 2 new quinolones: A 56619 (difloxacin) and A 56620. Comparison with pefloxacin, ofloxacin and ciprofloxacin]. / Activité antibactérienne in vitro de deux nouvelles quinolones: les A 56619 (difloxacine) et A 56620. Comparaison avec péfloxacine, ofloxacine et ciprofloxacine.

Minimal inhibitory concentration (MIC) of two new quinolones, A 56619 (difloxacin) and A 56620 were evaluated by agar dilution for 511 bacterial strains, in comparison with pefloxacin (PEF), ofloxacin (OFL) and ciprofloxacin (CIP). For Enterobacteriaceae, A 56620 (MIC 50 and 90 p. 100: 0,12 and 2 micrograms/ml) was less active than CIP (0,03 and 1) and more active than OFL (0,12 and 4) whereas A 56619 (1 and 16) appeared slightly inferior to PEF (0,25 and 8); the same range of activity was observed for Pseudomonas aeruginosa: CIP: 0,12-0,5; A 56620: 0,5-2; OFL and PEF: 1-4; A 56619: 1-8. For the majority of Acinetobacter (mode MIC: 0,5-1), Haemophilus (0,008-0,016), Meningococci (less than or equal to 0,008), Gonococci (0,06 à 0,25) and Legionella (0,12), activity of the two new compounds appeared very similar to those of the three other quinolones. A 56619 and A 56620 had a good activity (mode MIC: 0,25-0,5 micrograms/ml), similar to those of the three other quinolones, on Staphylococci sensitive strains whereas they were inactive on resistant strains. For Streptococci, A 56620 is about two times superior to A 56619; its activity is similar to that of PEF for Enterococci (mode MIC: 4) and to that of CIP on Streptococci A and Pneumococci (mode MIC: 0,5-1). For anaerobes, the two compounds had about the same activity similar to that of OFL and CIP (C. perfringens: 0,25-0,5 and B. fragilis: 4 micrograms/ml).

[In vitro effect of piperacillin on aerobic bacteria. Variations according to the phenotypes of resistance to beta-lactam antibiotics]. / Activité in vitro de la pipéracilline sur les bactéries aérobies. Variations selon les phénotypes de résistance aux bêta-lactamines.

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.

[In vitro activity of a new 3d-generation cephalosporin, cefodizime, on hospital bacteria]. / Activité in vitro d'une nouvelle céphalosporine de troisième génération, le céfodizime, sur les bactéries hospitalières.

Minimal inhibitory concentrations (MICs) of cefodizime were evaluated by agar dilution for 746 bacterial strains isolated in two hospitals. For enterobacteriaceae MICs ranged from 0.008 micrograms/ml to more than 128 micrograms/ml (mode MIC: 0.25); mode MICs varied across species, ranging from 0.016 micrograms/ml for Proteus mirabilis to 1 microgram/ml for Citrobacter; MICs ranged from 0.12 to 8 for most Enterobacter and from 1 to 64 for Serratia. The rare cefotaxime-resistant strains, most of which were Citrobacter or Enterobacter, also showed resistance to cefodizime. Cefodizime was noticeably less active against Pseudomonas aeruginosa and Acinetobacter, with MICs ranging from 32 to more than 128. Haemophilus sp. and Gonococci, regardless of beta-lactamase-production status, as well as Neisseria meningitidis, were highly susceptible (MIC less than or equal to 0.008-0.016). Cefodizime was moderately active against methicillin-susceptible Staphylococci (MIC: 2 to 16 micrograms/ml) and failed to inhibit methicillin-resistant strains. Enterococci were slightly susceptible or resistant. Whereas the other Streptococci and Pneumococci had low MICs (0.03-0.12). A fairly wide range of MICs was found for anaerobes, with lower values for Clostridium (0.008 to 1) than for Bacteroids (8 to 128 mu g/ml). Our results show that cefodizime has the same properties as other third-generation cephalosporins: cefotaxime-resistant Enterobacteriaceae strains also exhibit resistance to cefodizime.

[In vitro activity of carumonam (RO 17-2301) on hospital bacteria]. / Activité in vitro du carumonam (RO 17-2301) sur les bactéries hospitalières.

Minimal inhibitory concentrations (MICs) of carumonam (RO 17-2301), a new synthetic antibacterial agent of the monobactam group, were evaluated by agar dilution for 399 hospital isolates. RO 17-2301 was inactive against Gram positive and anaerobic bacteria. Most Enterobacteriaceae were inhibited by concentrations less than 1 microgram/ml, with mode MICs approximating 0.03 micrograms/ml except for Providencia (0.016), Citrobacter (0.06), Serratia (0.06) and Enterobacter (0.12). A few strains, most of which were Enterobacter or Citrobacter, had high MICs (greater than 8 micrograms/ml). RO 17-2301 was less active against Pseudomonas aeruginosa (mode MIC 2 micrograms/ml) and Acinetobacter (mode MIC 8-16 micrograms/ml). Haemophilus influenzae sp. were sensitive to RO 17-2301 (mode MIC 0.12-0.25), regardless of beta-lactamase production status; MICs ranged from 0.06 to 0.25 micrograms/ml for Meningococci, and from 0.008 to 0.06 for Gonococci except for a few strains that had higher MICs (0.25 to 0.5 and even 4 micrograms/ml). In vitro activity of RO 17-2301 on Gram negative bacteria proved similar to that of third-generation cephalosporins; cefotaxime-resistant Enterobacteriaceae are resistant to RO 17-2301.

[Multicenter study of ofloxacin activity on bacteria isolated from a hospital environment]. / Etude multicentrique de l'activité de l'ofloxacine sur les bactéries isolées en milieu hospitalier.

Minimal inhibitory concentrations (MICs) of ofloxacin were evaluated by agar dilution for 1508 bacterial strains isolated in five hospitals. For Enterobacteriaceae sensitive to nalidixic acid, MICs ranged from 0.008 to 1 microgram/ml (mode MIC: 0.12); the different species of Enterobacteriaceae exhibited similar mode MICs (0.12) with the exception of E. coli (0.06-0.12), P. mirabilis (0.5) and Providencia (0.25). Among strains intermediate and resistant to nalidixic acid, most of which were Serratia, Providencia and Citrobacter, 41% had a MIC within the susceptibility range, while the others had a MIC of 2 to 8 micrograms/ml, or even 64 micrograms/ml in a few instances. Ofloxacin also exhibited satisfactory activity against P. aeruginosa, with MICs ranging from 0.25 to 16 micrograms/ml (mode MIC: 2) for 87% of strains, and A. calcoaceticus, with MICs from 0.25 to 2 micrograms/ml (mode MIC: 1). Haemophilus sp. (MIC: 0.008 to 0.06 microgram/ml; mode MIC: 0.03), Gonococci (mode MIC: 0.008), and Meningococci (mode MIC: 0.016) were very sensitive to ofloxacin. The spectrum of ofloxacin included Gram positive cocci: MICs of Staphylococci were 0.06 to 2 micrograms/ml (mode MIC: 0.5); Enterococci, other Streptococci and Pneumococci were less sensitive, with MICs of 2 to 4 micrograms/ml for the majority of strains. As for anaerobic bacteria, ofloxacin proved more active against Clostridium (0.5 to 2 micrograms/ml) than Bacteroides (0.5 to 16 micrograms/ml).

[In vitro activity of ceftriaxone on hospital bacteria. Results of a multicenter study]. / Activité in vitro de la ceftriaxone sur les bactéries hospitalières. Résultats d'une étude multicentrique.

Minimal inhibitory concentrations (MICs) of ceftriaxone were determined by agar dilution for 2 099 strains isolated in six teaching hospitals. MICs were less than 1 microgram/ml for the great majority of Enterobacteriaceae, with mode MICs varying across groups from less than 0.008 micrograms/ml for Proteus (mirabilis and indole-positive) to 0.25 for Enterobacter. Only a few resistant strains were found, mainly among Enterobacter and Citrobacter. Ceftriaxone proved noticeably less active against P. aeruginosa and Acinetobacter (mode MICs: 16 micrograms/ml). Haemophilus sp. and Gonococci, regardless of beta-lactamase production status, as well as Neisseria meningitidis, were highly susceptible (MIC less than 0.008-0.032). Ceftriaxone was moderately active against methicillin-susceptible staphylococci (MIC: 2 to 8 micrograms/ml) and failed to inhibit methicillin resistant strains. Enterococci were slightly susceptible or resistant, whereas the other Streptococci and Pneumococci had low MICs (0.03-0.25). A fairly wide range of MICs was found for anaerobes (Clostridium: 0.06-2, Bacteroides: 0.5-32). Our data show that its particularly strong activity against Proteus, Haemophilus and Neisseria sets ceftriaxone apart from the other third-generation cephalosporins.

[Multicenter study of the in vitro effect of imipenem (N-formimidoyl-thienamycin) on hospital bacteria]. / Etude multicentrique de l'activité in vitro de l'imipenem (N. formimidoyl-thiénamycine) sur les bactéries hospitalières.

Minimal inhibitory concentrations (MICs) of imipenem were evaluated by agar dilution for 2 895 bacterial strains isolated in 9 hospitals. Imipenem proved highly active against Enterobacteriaceae, with an MIC less than or equal to 0.25 for 63% of the 1 556 tested strains, less than or equal to 1 for 89.6% and less than or equal to 4 for 99%. The different groups of Enterobacteriaceae exhibited similar mode MICs (0.12 to 0.25), with the exception of Serratia (0.25-0.5), P. mirabilis (0.5), indole-positive Proteus (2), and Providencia (1). MICs of most cefotaxime-resistant strains were within the susceptibility range. Imipenem also exhibited satisfactory activity against P. aeruginosa (mode MIC 1-2) and Acinetobacter sp. (mode MIC: 0.25-0.5). MICs ranged from 0.03 to 4 (mode MIC: 0.5) for Haemophilus sp. and 0.25 to 1 for Gonococci, regardless of beta-lactamase-production status. MICs for Meningococci were less than or equal to 0,06. Methicillin-susceptible Staphylococci had low MICs, ranging from 0.008 to 0.5 (mode MIC : 0.016); MICs for methicillin-resistant strains varied widely, from 0.016 to 64, and were higher after incubation at 30 degrees C. Streptococci, except for Enterococci, and Pneumococci were highly susceptible (usually 0.008-0.03); MICs for Enterococci varied from 0,12 to 32 (mode MIC: 1-2). Except for four C. difficile strains, all tested anaerobic strains were inhibited by concentrations less than or equal to 1 (mode MICs: 0.06 for C. perfringens and 0.03 for B. fragilis).

[Activity of the amoxicillin-clavulanic acid (augmentin) combination on strains of hospital isolates]. / Activité de l'association amoxicilline-acide clavulanique (augmentin) sur les souches d'isolement hospitalier.

All strains of Staphylococcus aureus and Gram negative bacilli (Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter) isolated from 01.01 to 03.31.83 were studied using agar diffusion with augmentin-impregnated discs (amoxicillin 20 micrograms + clavulanic acid 10 micrograms). Augmentin is active against penicillinase-producing Staphylococci susceptible to methicillin, whereas methicillin-resistant strains are also resistant to augmentin. According to the susceptibility of strains to amoxicillin, carbenicillin and cefalotin, Enterobacteriaceae can be divided into five main phenotypes, of which four are resistant. "RSR" and "RRR" phenotypes, which are cephalosporinase producers, are chiefly found among Enterobacter, Serratia, Citrobacter and indole + Proteus; in these groups a change in inhibition diameters indicating activity of augmentin is observed only in a significant number of Proteus vulgaris strains. "RRS" and "RRI" strains are penicillinase producers found mainly among E. coli, Klebsiella pneumoniae and oxytoca, and Proteus mirabilis; they emerge as very susceptible to augmentin. Pseudomonas aeruginosa is never susceptible to augmentin. Augmentin is slightly more active than amoxicillin on some Acinetobacter strains but the difference is too inconsiderable to be of clinical significance.

[In vitro activity of ceftizoxime on hospital bacteria. Results of a multicenter study]. / Activité in vitro du ceftizoxime sur les bactéries hospitalières. Resultats d'une étude multicentrique.

The susceptibility to ceftizoxime of all bacterial strains isolated from seven university-affiliated hospitals over one month was tested with disk-diffusion technique. Additionally, the MIC of 1937 strains selected at random was evaluated by the agar dilution method. The majority of Enterobacteriaceae are inhibited at a concentration of less than 1 microgram/ml with a mode MIC varying from 0.008 to 0.12 among the various groups. A few Enterobacter and Citrobacter strains are resistant. Little activity was demonstrated by ceftizoxime on Pseudomonas aeruginosa and Acinetobacter sp. (mode MIC 32 and 8 micrograms/ml respectively). Haemophilus sp. (MIC 0.01-0.03) and Neisseria (MIC less than 0,008-0,016) are very susceptible to the drug. The MIC of methicillin-sensitive strains of Staphylococcus aureus varies from 1 to 4 micrograms/ml ; Enterococci are less susceptible, whereas other Streptococci and Pneumococci have low MICs (less than 0.008-0.025). The susceptibility of anaerobic pathogens varies widely between species, and within species ; MIC ranges from 0.008 to 32 micrograms/ml for Clostridium sp. and 0.25 to 128 micrograms/ml for Bacteroides sp.

[In vitro activity of azthreonam on hospital Gram-negative bacilli. Results of a multicenter study]. / Activité in vitro de l'azthréonam sur les bacilles Gram négatifs hospitaliers. Résultats d'une étude multicentrique.

This work reports a multicenter study of antibacterial activity of azthreonam, a new antibacterial agent of the monobactam group, on Gram negative rods. Enterobacteriaceae are very sensitive to azthreonam (modal MIC: 0,06 micrograms/ml); some strains have higher MIC greater than or equal to 8 micrograms/ml, particularly among Enterobacter, Serratia and Citrobacter. Azthreonam has a good activity on Pseudomonas aeruginosa: 90% of the strains are inhibited by 8 micrograms/ml or less. Acinetobacter are less sensitive with a modal MIC of 32 micrograms/ml. Haemophilus are inhibited by low concentrations, 0,06 to 0,12 micrograms/ml usually.

[In vitro effect of rosoxacin on hospital bacteria. Results of a multicenter study]. / Activité in vitro de la rosoxacine sur les bactéries hospitalières. Résultats d'une étude multicentrique.

This work reports a multicenter study of antibacterial activity of rosoxacin, a new antibacterial agent of the quinolone group. Enterobacteriaceae are very sensitive to rosoxacin (modal MIC 0,5 micrograms/ml); resistant strains are observed in all species, but more often among Serratia and Citrobacter. Pseudomonas aeruginosa is less sensitive with a maximum number of strains between 2 and 8 micrograms/ml, so it is nearly for Acinetobacter. Haemophilus are very sensitive, having MIC of 0,03 and 0,06 micrograms/ml. The spectrum of rosoxacin includes Gram positive bacteria, since the MIC of Staphylococci are similar to Enterobacteriaceae; Enterococci are less sensitive, the major part of the strains being inhibited by 4 and 8 micrograms/ml.

[In vitro activity of cefatiolene (RP 42,980) against hospital bacteria. Comparison with cefotaxime and lamoxactam. Results of a multicenter study]. / Activité in vitro du céfatiolène (RP 42 980) sur les bactéries hospitalières. Comparaison avec céfotaxime et lamoxactam. Résultats d'une étude multicentrique.

This work reports a multicenter study of antibacterial activity of cefatiolene (RP 42 980), a new third generation cephalosporin, in comparison with cefotaxime and lamoxactam. On the basis of MIC, activity of the three products is similar or Gram negative rods, but cefotaxime is a little more active on Enterobacteriaceae. The activity against Staphylococci requires further studies, indeed the determination of IC 50 of some strains showed a better activity of cefatiolene, but this was not observed by determination of MIC. As cefotaxime and contrary to lamoxactam, cefatiolene is active at low concentrations on other Streptococci than Enterococci, but a little on Bacteroides.

[Multicenter study of the in vitro antibacterial activity of ceftazidime on gram-negative bacilli]. / Etude multicentrique de l'activité antibactérienne in vitro de la ceftazidime sur les bacilles gram négatifs.

This work reports a multicenter study of antibacterial activity of ceftazidime, a new third generation cephalosporin, on hospital Gram negative rods. Enterobacteriaceae are very sensitive to ceftazidime with a maximum number of strains inhibited by 1 microgram/ml or less (modal MIC 0, 125 microgram/ml); some resistant strains are observed, particularly among Enterobacter and Citrobacter. Activity of ceftazidime on Pseudomonas aeruginosa is superior to other third generation cephalosporins; modal MIC is 1 microgram/ml and 88% of the strains are inhibited by 4 microgram/ml or less. Acinetobacter are less sensitive to ceftazidime, with a modal MIC of 8 microgram/ml.

[Human pharmacology of ceftriaxone (author's transl)]. / Pharmacocinétique de la ceftriaxone chez l'homme.

The human pharmacology of ceftriaxone was studied in five healthy adult subjects receiving a 500 mg dose intravenously. Evolution of serum levels represents a two compartment open model; the distribution volumes, central and peripheric, were low (about 3 L); the elimination half-life was particularly long : 7.87 hours; the renal and serum clearances and low. These data are probably related to the high affinity of the drug for serum proteins (95 p. cent bound); they suggest once daily parenteral dosing.