REVIEWS OF INFECTIOUS DISEASES VOL. 4, SUPPLEMENT SEPTEMBER-OCTOBER 1982 1982 by The University of Chicago. All rights reserved. 0162-0886/82/0405-0015$02.00 Comparative Activity of Cefotaxime and Selected f3-lactam Antibiotics Against Haemophilus Influenzae and Aerobic Gram-Negative Bacilli H. J. Dabernat and C. Delmas From the Laboratories of Bacteriology and Virology, Faculty of Medicine, Centre Hospitalier Regional de Toulouse, Toulouse, France The activity of cefotaxime was compared with that of ampicillin, moxalactam, and cefoperozone against 50 isolates of Haemophilus influenzae and with that ofampicillin, carbenicillin, cephalothin, cefoxitin, cefamandole, cefazolin, and several other established and investigational f3-lactam antibiotics against several hundred isolates of gram-negative aerobic enteric bacilli. Minimal inhibitory concentrations of the drugs were determined by the agar plate dilution technique for H. influenzae and by the microtiter broth dilution technique for the other pathogens. Cefotaxime was the most active agent against H. influenzae; it was 20 times more active than ampicillin. It was also the most active agent against Escherichia coli, Klebsiella pneumoniae, nontyphoid Salmonella species, and Yersinia enterocolitica. Cefotaxime was among the most active agents against Enterobacter cloacae, Citrobacter species, Shigella species, Proteus mirabilis, and Acinetobacter calcoaceticus. None of the new cephalosporins or penicillin inhibited >90070 of the isolates of Pseudomonas aeruginosa at concentrations of 16 tjg/ml; these drugs were, however, more active than carbenicillin. Among the (J-Iactam antibiotics, ampicillin has been the most active against Haemophilus influenzae, carbenicillin and ticarcillin the most active against Pseudomonas aeruginosa, and cefuroxime and cefamandole the most active against the Enterobacteriaceae. Cefotaxime is a semisynthetic cephalosporin with great activity, a broad spectrum of antibiotic activity, and considerable (J-Iactamase stability [1-3]. This paper compares the activity of cefotaxirne with that of ampicillin, moxalactam, and cefoperazone against H. influenzae and with that of ampicillin, carbenicillin, and a wide range of cephalosporins against a variety of aerobic gram-negative enteric bacillary bacterial species. Materials and methods Organisms. Isolates of H.' influenzae capsular type B were cultured from clinical specimens (spinal fluid, blood, and sputum) taken from patients in Paris and Toulouse. Of the 50 strains, 14 were resistant to ampicillin and produced (J-Iactamase, as determined by tests with a chromogenic cephalosporin (nitrocefin, Glaxo, Please address requests for reprints to Dr. Charles E. Cherubin, The Jewish Hospital and Medical Center of Brooklyn, Room 113, 555 P.ospect Place, Brooklyn, New York 11238. Greenford, England). The isolates of Enterobacteriaceae, P. aeruginosa, and Acinetobacter calcoaceticus were cultured from a variety of clinical specimens (i.e., blood, urine, stool, sputum, pus, bile, and skin swabs), and species were determined by means of the API 20 E (API System, La Balme les Grottes, France). Susceptibility tests. The activities of the following antibiotics were tested: ampicillin (Bristol Laboratories, Paris), carbenicillin (Beecham Laboratories, Paris), cefotaxime (Hoechst-Roussel Pharmaceuticals, Paris), cephalothin (Eli Lilly, Paris), cephaloridine (Glaxo, Paris), cefoxitin (Merck Sharp & Dohme, Paris), cefamandole (Lilly), piperacillin (Lederle Laboratories, Paris), moxalactam (Lilly), mezlocillin (Bayer, Paris), cephalexin (Lilly), cefuroxime (Glaxo), ceftriaxone (Hoffmann-La Roche, Paris), and cefoperazone (Pfizer Laboratories Division, Paris). All drugs were tested against the gram-negative bacilli, whereas only ampicillin, cefotaxime, moxalactam, and cefoperazone were tested against H. influenzae. The MICs for H. influenzae were determined by the agar plate dilution method on Mueller-Hinton agar supplemented with 1070 Fildes (Difco Laboratories, Detroit, MI). Inocula of "-110 4 bacteria, grown in brain heart infusion broth with 10/0 Fildes and in a late phase of growth (i.e., after incubation for 18 hr at 37 C), were applied to agar 5401
5402 Dabernat and Delmas plates with a multipoint replicator. The MICs were determined after incubation overnight at 37 C in air. For all other organisms, the MICs were determined in Mueller-Hinton broth by the micromethod with the MIC 2000 inoculator and dilutor (Dynatech Laboratories, Alexandria, VA). Plates were read after incubation for 18 hr at 37 C. Results The MICs of the four fj-iactam drugs tested against H. influenzae are shown in table I. All three of the new fj-iactam agents are more active than ampicillin, even against strains that do not produce fj-lactamase; the MICs of the fj-lactam agents for all isolates are <1 ug/rnl. The most active drug, by a small margin, is cefotaxime, which is about 20 times more active than ampicillin against the non-fj-lactamase-producing strains and is quite potent against enzyme-producing strains. Table 2 shows the susceptibility of the various gram-negative bacilli to the 14 antibiotics tested. Against Escherichia coli and Klebsiella pneumoniae, the newer cephalosporins (cefotaxime, moxalactam, cefoperazone, and ceftriaxone) are considerably more active than the older agents. Cefotaxime is the most active of all agents against K. pneumoniae and the second most active (after ceftriaxone) against E. coli. Some strains of E. coli appear to be resistant to cefoperazone (MIC, 32 ug/ml), and some strains of Klebsiella definitely are resistant to cefoperazone and ceftriaxone (MIC, 64 ug/ml). For the isolates of E. cloacae, the MICs of all antibiotics vary widely, although the newer agents clearly are more active. Cefotaxime, moxalactam, and ceftriaxone appear to be equally active against this organism. Similar results are seen for the isolates of Citrobacter species, with cefoperazone, the least active of the four newer agents. The results are also similar for the isolates of Shigella species, Serratia species, nontyphoid Salmonella species, Yersinia entero- colitica, and Proteus mirabilis. Although some strains of Acinetobacter calcoaceticus are extremely sensitive to the four newer agents (MIC, <0.1 ug/ml), the MIC so (i.e., the lowest concentration inhibiting growth of 50070 of tested strains) of 16 ug/rnl shows that at least half of the isolates are not nearly as sensitive as those of other species. With P. aeruginosa, an entirely different range of MICs is seen. Very wide ranges are noted for the newer agents and for carbenicillin, mezlocillin, and piperacillin. None of the four new fj-lactam agents shows a clear advantage over piperacillin. All agents except moxalactam and cefoperazone fail to inhibit some proportion of strains of P. aeruginosa (with an inoculum of 10 4 ) at a concentration of 128 ug/rnl (table 3). Discussion The results presented here demonstrate the high degree of in vitro activity of cefotaxime against H. influenzae thus confirming the results already published by other workers [4-6]. Cefotaxime not only is more active than other cephalosporins, but is even more active than ampicillin, which until now has been considered the drug of choice for the treatment of diseases caused by H. influenzae [7-9]. Cefotaxime is, in fact, 20 times more active than ampicillin and, according to the literature [6, 10], is 25 times more active than cefamandole, 150 times more active than cefoxitin and cephalothin, and 200 times more active than cefazolin and cephaloridine. Because of the low MIC values (0.3-0.25 ug/ml) for even the fj-iactamaseproducing strains, cefoperazone, moxalactam, and particularly cefotaxime soon may become the preferred antibiotic for the treatment of infections caused by H. influenzae, even those of the central nervous system, for which their extraordinary antimicrobial activity may suit them uniquely. Against E. coli, K. pneumoniae, E. cloacae, Table 1. In vitro susceptibility of 50 isolates of Haemophilus influenzae to four antimicrobial agents. No. of isolates susceptible at indicated MIC (J.tg/ml) Agent 0.OO3 0.007 0.015 0.03 0.06 0.12 0.25 0.50 2 4 8 Ampicillin 0 0 0 3 1 4 27 1 7 3 1 3 Cefotaxime 3 9 26 6 3 1 2 0 0 0 0 0 Moxalactam 3 1 0 12 29 2 3 0 0 0 0 0 Cefoperazone 5 9 17 9 8 1 1 0 0 0 0 0
Table 2. In vitro susceptibility of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Citrobacter species, Shigella species, Serratia species, nontyphoid Salmonella species, Yersinia enterocolitica, Proteus mirabilis, and Acinetobacter calcoaceticus. MIC range/mic,o/mic9o (JAg/ml) for indicated organism" E. coli K. pneumoniae E. cloacae Citrobacter Shigella Agent (n = 104) (n = 1(4) (n = 81) (n = 77) (n = 40) Ampicillin 0.5->128/2/128 4->128/64/>128 1->128/128/>128 1->128/>128/>128 0.5->128/2/4 Carbenicillin 1->128/4/128 1->128/128/>128 1->128/8/>128 1->128/>128/>128 1->128/4/8 Mezlocillin 0.5->128/2/128 0.5->128/8/>128 1->128/4/>128 1->128/>128/>128 0.5->128/2/4 Piperacillin 0.12->128/1/128 0.5->128/8/>128 0.5->128/4/>128 1->128/>128/>128 0.25->128/1/2 Cephalothin 1->128/8/32 0.5->128/4/64 2->128/>128/>128 1->128/>128/>128 1-32/8/8 Cefazolin 1->128/2/32 0.25->128/2/32 8->128/>128/>128 4->128/>128/>128.../.../... Cephalexin 2->128/4/16 4->128/4/8 4->128/128/>128 4->128/64/>128 4-16/8/8 Cefamandole 0.12->128/0.5/4 0.25->128/1/64 0.25->128/8/>128 0.5->128/4/128 0.12-16/0.25/0.5 Cefuroxime 0.5->64/2/4 0.12->128/2/4 1->128/8/32 0.5->128/2/8 1-16/2/4 Cefoxitin 1-128/2/4 0.5-128/2/4 2->128/64/>128 1->128/64/128 1-8/214 Cefotaxime 0.015-4/0.06/0.12 0.015-4/0.06/0.06 0.03-64/0.12/0.5 0.03-32/0.12/0.25 0.015-0.06/0.03/0.06 Moxalactam 0.03-110.06/0.25 0.03-4/0.1210.25 0.03-3210.12/0.5 0.03-64/0.1210.25 0.06-0.25/0.06/0.12 Cefoperazone 0.03-3210.12/1 0.015-64/0.5/32 0.03-64/0.25/64 0.06-64/4/64 0.03-64/0.12/0.25 Ceftriaxone 0.015-4/0.03/0.06 0.015-64/0.03/0.12 0.015-64/0.25/0.5 0.03-64/0.12/0.5 0.015-0.06/0.03/0.06 MIC range/ml'co./ml'cs, (jjg/ml) for indicated organism" Nontyphoid Serratia Salmonella Y. enterocolitica P. mirabilis A. calcoaceticus Agent (n = 80) (n = 50) (n = 22) (n = 76) (n = 65) Ampicillin 4->128/>128/>128 0.5->128/1/2 4-16/8/16 0.05->128/1/>128 0.5->128/128/>128 Carbenicillin 1->128/>128/>128 2->128/4/8 1->128/128/128 0.5->128/1/>128 2->128/32/>128 Mezlocillin 2->128/ 128/>128 1->128/4/4 or 64 0.12-2/0.5/1 0.12->128/1/>128 2->128/64/>128 Piperacillin 1->128/ 128/>128 0.5->128/214 or 64 0.25-2/1/2 0.06->128/0.25/>128 1->128/321>128 Cephalothin 128->128/>128/>128 1->128/2/8 8-64/16/32 0.5-128/4/32 8->128/>128/>128 Cefazolin >128/>128/>128 0.5-4/1/2 2-8/4/4 2-32/4/32 16->128/>128/>128 Cephalexin.../.../... 2-3214/8 4-8/4/8 8->128/16/32 8->128/>128/>128 Cefamandole 2->128/128/>128 0.25->128/0.5/2 0.12-0.5/0.5/0.5 0.25->128/1/16 4->128/128/>128 Cefuroxime 8->128/128/>128 0.25-32/4/4 0.12-1/0.5/1 0.5-32/1/2 2->128/321128 Cefoxitin 4->128/16/32 0.5-8/2/4 0.25-16/2/8 1-8/2/4 2->128/64/>128 Cefotaxime 0.06-64/0.5/4 0.03-1/0.06/0.12 0.015/0.01510.015 0.015-0.06/0.015/0.03 0.12-64/16/32 Moxalactam 0.06-2/0.25/1 0.03-4/0.06/0.12 0.015-0.06/0.03/0.06 0.015-0.5/0.1210.12 0.06-64/32/64 Cefoperazone 0.5-64/16/32 0.12->128/0.25/4 0.06-2/1/1 0.06-64/0.5/16 0.25-64/64/64 Ceftriaxone 0.06-16/0.5/4 0.03-110.06/0.06 0.015-0.06/0.015/0.03 0.015-0.03/0.015/0.015 0.12-64/16/32 The MIC,o and MIC90 are the lowest concentrations inhibiting growth of 50010 and 90% of tested strains, respectively. g I::l (;;.... o :::I : s :::I.. C/) w
S404 Dabernat and Delmas Table 3. In vitro susceptibility of Pseudomonasaeruginosa(n 34). Agent MIC range MIC so MIC 90 Ampicillin >128 >128 >128 Carbenicillin 32->128 64 >128 Mezlocillin 16->128 32 >128 Piperacillin 2->128 8 128 Cephalothin >128 >128 >128 Cefazolin >128 >128 >128 Cephalexin >128 >128 >128 Cefamandole >128 >128 >128 Cefuroxime >128 >128 >128 Cefoxitine 64->128 >128 >128 Cefotaxime 8->128 32 >128 Moxalactam 8->128 16 32 Cefoperazone 2->128 8 16 Ceftriaxone 8->128 32 >128 NOTE. MIC so and MIC 90 = the concentration of drug required to inhibit 50070 and 90010, respectively, of the isolates. Values are given as /Ag/ml. Serratia species, P. mirabilis, nontyphoid Salmonella species, Shigella species, and Yersinia enterocolitica, the four new (J-Iactam agents (moxalactam, cefotaxime, cefoperazone, and ceftriaxone) are much more active than the older cephalosporins already in clinical use. Cefoperazone is the least active of the four; a few isolates of nearly every species have MIC values that may indicate clinical resistance. Cefotaxime is either the most active or equal in activity to ceftriaxone and moxalactam against the strains tested. Against A. calcoaceticus, the four new agents are more active than the older ones, but by a much smaller margin. At least 10070 of the isolates are sensitive only to 32 or 64 ug/rnl. Unless large doses of the agents are used, these isolates probably should be considered clinically resistant. Against P. aeruginosa, the large margin between the activity of older and newer agents does not exist; cefotaxime, moxalactam, cefoperazone, and ceftriaxone appear to be slightly more active than carbenicillin and mezlocillin and slightly less active than piperacillin. Our findings agree with the extensive literature on the antimicrobial activity of the latter agents [11-17]. Since none of these older agents is presently considered appropriate for monotherapy in severe infections due to P. aeruginosa or even for therapy before sensitivity testing in minor infections, the new agents will probably be inappropriate also in such instances. The possible synergy of the new (3-lactam agents must be studied and any synergistic effects confirmed in vivo. References 1. Chabbert, Y. A., Dang Van, A., Labia, R. Comparative antibacterial activity of HR 756, a syn isomer of a methoxy-imino cephalosporin [abstract no. 76]. In Proceedings of the 18th Interscience Conference on Antimicrobial Agents and Chemotherapy, Atlanta, Oct. 1-2, 1978. American Society for Microbiology, Washington, D.C., 1978. 2. Fu, K. P., Neu, H. C. Beta-lactamase stability of HR 756, a novel cephalosporin, compared to that of cefuroxime and cefoxitin. Antimicrob. Agents Chemother. 14:322 326, 1978. 3. Peronnet, J., Bucourt, R., Heymes, R., Bormann, D., Durckheimer, W. Chemical and physicochemical profiles of the new cephalosporin derivative HR 756 [abstract no. 75]. In Proceedings of the 18th Interscience Conference on Antimicrobial Agents and Chemotherapy, Atlanta, Oct. 1-2, 1978. American Society for Microbiology, Washington, D.C., 1978. 4. Drasar, F. A., Farrell, W., Howard, A. J., Hince, c., Leung, T., Williams, J. D. Activity of HR 756 against Haemophilus influenzae, Bacteroides fragilis and gramnegative rods. J. Antimicrob. Chemother. 4:445-450, 1978. 5. Hamilton-Miller, J. M. T., Brumfitt, W., Reynolds, A. V. Cefotaxime (HR 756), a new cephalosporin with exceptional broad-spectrum activity in vitro. J. Antimicrob. Chemother. 4:437-444, 1978. 6. Dabernat, H. J., Buu-Hoi-Dang Van, A., Delmas, c., Bauriaud, R. Comparative activities of cefotaxime, a new cephalosporin derivative, and of selected beta-lactam antibiotics against Haemophilus species. Ann. Microbiol. (Paris) 130A:461-467, 1979. 7. Jorgensen, J. H., Alexander, G. A. Comparative activities of selected beta-iactam antibiotics against Haemophilus influenzae. Antimicrob. Agents Chemother. 13:342 343, 1978. 8. Kattan, S., Cavanagh, P., Williams, J. D. Relationship between f3-lactamase production by Haemophilus influenzae and sensitivities to penicillins and cephalosporins. J. Antimicrob. Chemother. 1:79-84, 1975. 9. Wise, R., Rollason, T., Logan, M., Andrews, J. M., Bedford, K. A. HR 756, a highly active cephalosporin: comparison with cefazolin and carbenicillin. Antimicrob. Agents Chemother. 14:807-811, 1978. 10. Dabernat, H., Bauriaud, R., Delmas, c., Lefevre, J. c., Lemozy, J., Lareng, M. B. Sensibilite d'haemophilus influenzae a huit antibiotiques. Isolement de souches multi-resistantes, Medecine et Maladies Infectieuses 8:244-249, 1978. 11. Fu, K. P., Neu, H. C. Azlocillin and mezlocillin: new ureido penicillins. Antimicrob. Agents Chemother. 13:930-938, 1978. 12. Fu, K. P., Neu, H. C. Piperacillin, a new penicillin active
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