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C Chanal

Publications and source records attributed to C Chanal.

47 records · Page 3Linked to original sources
PubMed1990

[Piperacillin-amikacin combinations: killing curves].

Bactericidal activity as a function of time of piperacillin (PIP) and amikacin (AKN) alone and in combination was evaluated by killing curves technique on 23 clinical isolates: E. coli (6), K. pneumoniae (5), E. cloacae (6) and P. aeruginosa (6), for which the minimal inhibitory concentrations ranges of piperacillin were 0.25 to 64 mg/l and of amikacin 1 to 8 mg/l. For each species, the strains were chosen according to the most frequent phenotypes: beta-lactams susceptible, penicillinase (Pase), cephalosporinase (Case) and Pase + Case producers. Killing curves were carried out with the following concentrations (mg/l): piperacillin (2, 16, 64); amikacin (4, 8, 16); piperacillin (2) + amikacin (4); piperacillin (16) + amikacin (8); piperacillin (64) + amikacin (16). Antibiotic concentrations corresponded to pharmacokinetics and/or to critical values of piperacillin and amikacin. Bactericidal activity was defined as a 4 log 10 decrease in CFU/ml between 2 and 24 hours. When piperacillin (64) was combined with amikacin (16), the bactericidal effects were nearly the same as those with amikacin alone. But piperacillin (16) + amikacin (8) combination had bactericidal effect for the majority of strains (21/23) and it prevented for some of them the bacterial regrowth observed with amikacin alone at the same concentration. A bactericidal activity without regrowth (until the 24th hour) was obtained for 9 strains; 2 susceptible E. coli, 3 K. pneumoniae (chromosomal Pase producer) and 4 cefotaxime susceptible E. cloacae, with low dose combination piperacillin (2) + amikacin (4). Finally, only combinations piperacillin (64) + amikacin (16) or piperacillin (16) + amikacin (8) had bactericidal activity on 2 Ticarcillin-resistant P. aeruginosa, the two antibiotics being separatedly bacteriostatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Amikacin↗
PubMed1990

[In vitro antibacterial activity of RU 51746 (sodium salt of cefpodoxime). Results of a multicenter study].

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.

Anti-Bacterial Agents↗
PubMed1989

Comparative study of five plasmid-mediated ceftazidimases isolated in Klebsiella pneumoniae.

Five plasmid-mediated beta-lactamases conferring a high level of resistance to ceftazidime were isolated from Klebsiella pneumoniae strains. These ceftazidimases (CAZ) differed in their isoelectric point (from 5.3 to 8.2) and were encoded by large self-transferable plasmids of 85 kb (CAZ-2, CAZ-3) or greater than or equal to 150 kb (CAZ-1, CAZ-4, CAZ-5). The 85 kb plasmids seemed closely related to pCFF04 encoding CTX-1 enzyme and belonged to the same incompatibility group 7 or M. These beta-lactamases hydrolysed all beta-lactams with the exception of cephamycins and carbapenems. For CAZ-1, CAZ-2 and CAZ-3 producers, MICs of ceftazidime (32-256 mg/l) were higher than MICs of cefotaxime (0.12-2 mg/l) and aztreonam (1-16 mg/l). For the strains producing the beta-lactamases CAZ-4 and CAZ-5, MICs of aztreonam were the highest (greater than or equal to 256 mg/l). The impaired activities of cephalosporins and monobactams were restored equally well by 2 mg/l of clavulanate, sulbactam and CL-298741 for CAZ-2 producing strains (wild type and transconjugant). Sulbactam (2 mg/l) had a lower protective effect than other inhibitors on ceftazidime for CAZ-1 and CAZ-3 producing K. pneumoniae. The protective effect of sulbactam (2 mg/l) was lower than that of the other inhibitors on all beta-lactams for CAZ-4 and CAZ-5 producers. The enzymes CAZ-1, CAZ-2 and CAZ-3 derived from TEM beta-lactamase whereas CAZ-4 and CAZ-5 derived from SHV-1 enzyme.

Autoradiography↗
PubMed1989

Comparative in-vitro activity of meropenem against clinical isolates including Enterobacteriaceae with expanded-spectrum beta-lactamases.

Meropenem, a new parenteral carbapenem, was tested in vitro by an agar-dilution method against 373 standard strains (aerobes and anaerobes) and against nine expanded-spectrum beta-lactamase-producing strains and their transconjugants (5 CTX-1, 2 CAZ-1, 2 CAZ-2). Meropenem was compared with methicillin, imipenem, piperacillin, cefoxitin, cefotaxime, ceftazidime, gentamicin, chloramphenicol, clindamycin, ciprofloxacin, vancomycin and metronidazole. Meropenem and imipenem exhibited an extended spectrum of activity, with low MICs. Only methicillin-resistant staphylococci, and Pseudomonas (Xanthomonas) maltophilia were resistant. Of the carbapenems, imipenem was more active against methicillin-susceptible staphylococci, streptococci and Enterococcus faecalis, but meropenem was markedly more active against all the Enterobacteriaceae and some pseudomonads. Both had similar activity against Ps. aeruginosa, Acinetobacter spp. and anaerobes. The carbapenem MICs were very low for Enterol acteriaceae producing the expanded-spectrum beta-lactamases. Against CTX-1-producing strains resistant to cefotaxime and ceftazidime and against CAZ-1 or CAZ-2-producers highly resistant to ceftazidime meropenem was the most active, with MICs lower (0.03-0.12 mg/l) than those of imipenem (0.06-0.5 mg/l), for wild type producers and their transconjugants.

Bacteria↗
PubMed1989

Interactions of meropenem, with beta-lactamases, including enzymes with extended-spectrum activity against third-generation cephalosporins.

The interactions of a meropenem were studied with a set of beta-lactamases including the new TEM- and SHV-related plasmid-mediated enzymes that have extended-spectrum activity against third-generation cephalosporins ('cefotaximases' and 'ceftazidimases'). Meropenem and imipenem were highly resistant to the hydrolytic activity of all the TEM and SHV related beta-lactamases, and to the OXA enzymes, as were the cephamycins: cefoxitin and cefotetan. The two carbapenems were also highly stable to Class C beta-lactamases (chromosomal cephalosporinases) whereas third-generation cephalosporins and cephamycins were slowly hydrolyzed. Both carbapenems demonstrated quite similar affinities for all the enzymes studied. In some instances, and particularly with Class A (TEM- and SHV-derived) enzymes, meropenem inactivated the beta-lactamase activity. Imipenem appeared less reactive in this respect.

Acylation↗
PubMed1989

Prospective survey of colonization and infection caused by expanded-spectrum-beta-lactamase-producing members of the family Enterobacteriaceae in an intensive care unit.

The occurrence of expanded-spectrum-beta-lactamase-producing strains was prospectively studied in 56 patients in an intensive care unit. Ten patients were infected or colonized; some of these patients had asymptomatic intestinal colonization. Four different expanded-spectrum beta-lactamases were identified and used as epidemiological markers to survey nosocomial infections.

Acute Kidney Injury↗
PubMed1987

Spondylitis and osteomyelitis caused by Kingella kingae in children.

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.

Bacterial Infections↗
PubMedDate not supplied

Susceptibility of new beta-lactams to the expanded-spectrum beta-lactamase CTX-1.

Forty-three clinical isolates of enterobacteria were selected for the production of the new plasmid-mediated expanded-spectrum beta-lactamase CTX-1. The geometric means of MICs were ranged as follows: ticarcillin, greater than 4096 mg/l; ticarcillin + clavulanic acid (2 mg/l), 64-87 mg/l; LY 163892, 8.0-69.1 mg/l; cefotaxime, 5.7-26.4 mg/l; temocillin, 8.0-21.8 mg/l; Ro 158074, 4.0-18.7 mg/l aztreonam, 1.0-14.4 mg/l and BMY 28142, 1.4-2.8 mg/l. Moxalactam, imipenem and CM 40876 were resistant to hydrolysis and MICs were lower than 2.0 mg/l. A high protective effect on cefotaxime (MIC less than or equal to 0.5 mg/l) was obtained by sulbactam (4 mg/l). Escherichia coli transconjugants from each species showed similar levels of MICs.

Anti-Bacterial Agents↗
PubMedDate not supplied

Klebsiella pneumoniae and other Enterobacteriaceae producing novel plasmid-mediated beta-lactamases markedly active against third-generation cephalosporins: epidemiologic studies.

Analysis of the enzymes produced by clinical isolates of multiresistant Klebsiella pneumoniae from hospitals in France revealed two novel broad-spectrum beta-lactamases. The first, characterized by an isoelectric point of 6.3 and a high hydrolytic activity on cefotaxime, is designated CTX-1. This beta-lactamase was encoded by a 95-kilobase plasmid (incompatibility group 7M) and cotransferred with resistance to tetracyclines, sulfonamides, and aminoglycosides (AAC [6']-IV). From 1984 to June 1987, 490 CTX-1-producing strains of Enterobacteriaceae were isolated. The second plasmid-mediated beta-lactamase (CAZ-1) was isolated in 1987 from three K. pneumoniae strains more resistant to ceftazidime than to other third-generation cephalosporins. This broad-spectrum beta-lactamase differed from CTX-1 by its isoelectric point--close to 5.6--and its high hydrolytic activity on ceftazidime and was encoded by a 150-kilobase plasmid. It was demonstrated that these expanded-spectrum beta-lactamases are TEM derivatives.

Cephalosporins↗