C. Roy

Activity of ciprofloxacin (BAYo 9867) against Pseudomonas aeruginosa and ampicillin-resistant enterobacteriaceae

SummaryWe studied thein vitro activity of ciprofloxacin against 570 strains of ampicillin-resistantEnterobacteriaceae and 286Pseudomonas aeruginosa strains. 95.26% of theEnterobacteriaceae and 53.45% of theP. aeruginosa were inhibited by 0.1 mg/l of ciprofloxacin. 2 mg/l of ciprofloxacin inhibited all of theEnterobacteriaceae strains and 4 mg/l all of theP. aeruginosa. We compared the activity of ciprofloxacin with that of temocillin in theEnterobacteriaceae strains. In theP. aeruginosa strains, classified according to their susceptibility to carbenicillin and gentamicin, we compared the activity of ciprofloxacin with that of ceftazidime. In the strains studied, thein vitro activity of ciprofloxacin is superior to that of temocillin against theEnterobacteriaceae and to that of ceftazidime against theP. aeruginosa strains.ZusammenfassungEs wurde die Wirksamkeitin vitro von Ciprofloxacin bei 570 Ampicillin-resistentenEnterobacteriaceae- und 286Pseudomonas aeruginosa-Stämmen untersucht. 95,26% derEnterobacteriaceae- und 53,45% derP. aeruginosa-Stämme wurden mit 0,1 mg/l Ciprofloxacin gehemmt. 2 mg/l von Ciprofloxacin hemmten alleEnterobacteriaceae-Stämme und 4 mg/l alleP. aeruginosa-Stämme. Bei denEnterobacteriaceae-Stämmen wurde die Wirksamkeit von Ciprofloxacin mit der von Temocillin verglichen. Bei den nach Carbenicillin- und Gentamicin-resistenten Isolaten klassifiziertenP. aeruginosa-Stämmen verglichen wir die Aktivität von Ciprofloxacin und Ceftazidim. Bei den den untersuchtenEnterobacteriaceae-Stämmen ist die Wirksamkeit von Ciprofloxacinin vitro höher als die von Temocillin und bei denP. aeruginosa-Stämmen höher als die von Ceftazidim.

FREQUENCY OF PLASMID-MEDIATED BETA-LACTAMASES IN ENTEROBACTERIACEAE ISOLATED IN SPAIN

1. Akalin HE, Laleli Y, Telatar H: Bactericidal and opsonic activity of ascitic fluid from cirrhotic and noncirrhotic patients. Journal of Infectious Diseases 1983, 147: 1011-1017. 2. AkaUn HE, Laleli Y, Telatar H: Serum bactericidal and opsonic activities in patients with non-alcoholic cirrhosis. Quarterly Journal of Medicine 1985, 56: 431437. 3. Wyke R J: Problems of bacterial infection in patients with liver disease. Gut 1987, 28: 623-641. 4. Rivera JM, Garcia-Bragado F, Gomez FA, Grilo A, Lozano-Gutierrez IF: Brucella pericarditis. Infection 1988, 16: 254. 5. AI-Awadhi NZ, Ashkenanl F, Khalafo ES: Acute pancreatitis associated with brucellosis. American Journal of Gastroenterology 1989, 84: 1570-1574. 6. Vandercam B, Zech F, Cooman S, Bughin C, Gigi J, Wauters G: Isolatiofi of Brucella rnelitensis from human sperm. European Journal of Clinical Microbiology & Infectious Diseases 1990, 9: 303-304. 7. Diab SM, Araj GF, AI-Asfour A J, AI-Yusuf AR: Brucellosis: atypical presentation with peritonitis and meningitis. Tropical and Geographical Medicine 1989, 41: 160--163. 8. AI-Mudailal DS, Mousa ARM, Marafie AA: Apyrexic Brucella rnelitensis aortic valve endocarditis. Tropical and Geographical Medicine 1989, 41: 372-375. 9. Runyon BA, Umland ET, Merlin T: Inoculation of blood culture bottles with ascitic fluid: improved detection of spontaneous bacterial peritonitis. Archives of Internal Medicine 1987, 147: 73-75. 10. Bobadilla M, Sifuentes J, Garcia-Tsao G: Improved method for bacteriological diagnosis of spontaneous bacterial peritonitis. Journal of Clinical Microbiology 1989, 27: 2145-2147. 11. Baykal M, Akalin HE, Firat M, Serin A: In vitro activity and clinical efficacy of ofloxacin in infections due to Brucella melitensis. Reviews of Infectious Diseases 1989, 11, Supplement 5: 993-994. 12. Rubinstein E, Lang R, Shasha B, Hagar B, Diamanstein L, Joseph G, Anderson M, Harrison K: In vitro susceptibility of Brucella melitensis to antibiotics. Antimicrobial Agents and Chemotherapy 1991, 35: 19251927. 13. Akalin HE, ~nal S, Giir D, Baykal M: Ofloxacin in the treatment of brucellosis. European Journal of Clinical Microbiology & Infectious Diseases 1991, 10, Special Issue: 326-328. 14. AI-Sibai MB, Halim MA, El-Shaker MM, Khan BA, Qadri SMH: Efficacy of ciprofloxacin for treatment of Brucella melitensis infections. Antimicrobial Agents and Chemotherapy 1992, 36: 150-152. 15. Siivian C, Bouquet S, Breux JP, Beek.Giraudian B, Beauchont M: Oral pharmacokinetics and ascitic fluid penetration of ofloxacin in cirrhosis. European Journal of Clinical Pharmacology 1989, 37: 261-265. Frequency of Plasmid-Mediated Beta-Lactamases in Enterobacteriaceae Isolated in Spain

Characterization of penicillinase-producing strains of Neisseria gonorrhoeae.

Twenty-three penicillinase-producing strains ofNeisseria gonorrhoeae were characterized. All strains showed hybridization with a TEM-1 probe and production of a TEM-1 type beta-lactamase (pI 5.4) on isoelectric focusing. Eight strains also showed a beta-lactamase band of pI 5.5. The penicillin MICs for the strains producing only TEM-1 were in the range 4–16 µg/ml; MICs of the strains with the additional pI 5.5 band were≥128 µg/ml for seven strains and 4 µg/ml for an arginine-hypoxanthine dependent strain. The association of the high MICs with the presence of the pI 5.5 band was statistically significant. The pI 5.5 band could represent a new beta-lactamase type or a TEM-1 mutant.

Activity of carumonam and aztreonam againstKlebsiella species

combination with 0.1 or 1.0/ag gentamicin/ml were studied. Piperacillin, mezlocillin, cefotaxime, ceftizoxime, cefoperazone and ceftriaxone were themost active antibiotics, with a bactericidal concentration < 0.02 mr/1 (Table). Penicillin G, ampicillin, impenem, cefamandole and moxalactam were approximately ten-fold less active, with a bactericidal concentration ~< 0.2 rag/1. Penicillin V, methicillin, cephalothin, cefoxitin, chloramphenicol and rifampin had a bactericidal concentration ~ 1.0 rag/1. Gentamicin had a median MBC of 1.6 mg/1, whereas amikacin had a median MBC of 12.6 mg/1. Tetracycline had a median MBC of 6.25 rag/1. Clindamycin and vancomycin were the least active antibiotics, with bactericidal concentrations >/50 rag/1. A 15-800 fold diminution in activity was observed when inoculum size was increased from 103 to 10 6 CFU/ml in tests against piperacillin, ceftizoxime and methicillin. No such effect was observed with penicillin or gentamicin. Growth of the organisms in the presence of gentamicin parallelled growth in the absence of antibiotic. Growth of the organism in the presence of ceftizoxime and piperaciltin at the MIC showed a 1 log reduction in viable colony count after 6 h and a 2 3 log reduction after 24 h. Penicillin alone resulted in a 1 log reduction after 6 h, but a marked reduction to ~< 10 organisms/ml after 24 h. There was 1.5 log difference between the viable count for penicillin alone and for penicillin in combination with gentamicin after 6 h. The overall pattern of susceptibility of Pasteurella multocida to conventional antibiotics was similar to that described previously (4). Penicillin G was found to be the most active antibiotic, with a median MBC of ~< 0.2 mg/l. Ampicillin, penicillin V, carbenicillin, cephalothin and chloramphenicol also showed good bactericidal activity. Tetracycline appeared to be bacteriostatic, and antistaphylococcal antibiotics generally exhibited poor activity. Piperacillin, mezlocillin, cefotaxime, ceftizoxime, cefoperazone and ceftriaxone were ten-fold more active than penicillin G while the activity of impenem, moxalactam and cefamandole was equivalent to that of penicillin G. Inoculum size may be an important factor in antibiotic susceptibility tests with broad-spectrum peniciUins and cephalosporins. Growth kinetic studies suggest that gentamicin alone may be suboptimal in the treatment of Pasteuretlamultocida infections despite apparent in vitro susceptibility; an additive effect was demonstrated when penicillin G was combined with gentamicin.

Complementary activity of mezlocillin and the combination of amoxicillin with clavulanic acid on Enterobacteriaceae

SummaryThe MICs of amoxicillin, mezlocillin and BRL 25,000, a combination of two parts amoxicillin and one part clavulanic acid (2AM + 1CA), were measured for 331Enterobacteriaceae strains which produced beta-lactamases as demonstrated by nitrocefin. The MIC values for mezlocillin and the combination 2AM + 1CA were very similar for the total number of the strains investigated. When investigated separately according to the bacterial species, three different sensitivity groups were established for the above-mentioned preparations: 1) species with the same or similar sensitivity to mezlocillin and 2AM + 1CA (Escherichia coli andShigella spp., amoxicillin-resistant strains); 2) species which were more sensitive to mezlocillin than to the combination 2AM + 1CA (Citrobacter spp.,Enterobacter cloacae, Serratia spp. and indole-positiveProteus as well as strains ofE. coli andShigella spp. which produce a cephalosporinase and are sensitive to amoxicillin); 3) species which are more sensitive to 2AM + 1CA than to mezlocillin (amoxicillin-resistantSalmonella spp.,Proteus mirabilis andKlebsiella pneumoniae). This complementary activity of mezlocillin and 2AM + 1CA againstEnterobacteriaceae depended on the beta-lactamases produced.ZusammenfassungDie MHK für Amoxicillin, Mezlocillin und BRL 25000 sowie eine Kombination von zwei Teilen Amoxicillin plus einem Teil Clavulansäure (2AM + 1CA) wurde für 331Enterobacteriaceae-Stämme getestet; alle diese Stämme produzierten β-Laktamasen, die mit Nitrocefin nachgewiesen worden waren. Die MHK-Werte für Mezlocillin und die Kombination 2AM + 1CA waren bei den untersuchten Stämmen insgesamt sehr ähnlich. Bei der getrennten Auswertung nach Stämmen und Keimarten ergeben sich für die überprüften Wirkstoffe drei Empfindlichkeitsgruppen: 1) Keimarten mit der gleichen oder einer ähnlichen Empfindlichkeit für Mezlocillin und 2AM + 1CA (Escherichia coli, Shigella spp., Amoxicillin-resistente Stämme), 2) Keimarten, die für Mezlocillin empfindlicher waren als für die Kombination 2AM + 1CA (Citrobacter spp.,Enterobacter cloacae, Serratia spp., indolpositiveProteus spp. sowie solche Stämme vonE. coli undShigella spp., die eine Cephalosporinase produzieren und auf Amoxicillin ansprechen), 3) Keimarten, die für 2AM + 1CA empfindlicher sind als für Mezlocillin (Amoxicillin-resistenteSalmonella spp.,Proteus mirabilis undKlebsiella pneumoniae). Diese deutliche komplementäre Wirkung von Mezlocillin und 2AM + 1CA aufEnterobacteriaceae hängt von den Stammeigenschaften und der gebildeten β-Laktamase ab.