Y. Ueno

In vitro Activity of Quinupristin/ Dalfopristin, RP59500, against Gram-Positive Clinical Isolates

Synercid (quinupristin/dalfopristin, RP59500) is a new water-soluble streptogramin which offers some advantages over the commercially available antimicrobials against drug-resistant gram-positive bacteria. Its in vitro activity was compared with ampicillin, augmentin, penicillin, erythromycin, oxacillin and vancomycin against gram-positive bacteria isolated from clinical specimens. Of the 837 gram-positive bacteria tested 834 (99.6%) were inhibited by < 0.6-4.0 mg/l of Synercid. It had excellent activity against both staphylococci and streptococci, including methicillin-resistant staphylococci and vancomycin-resistant enterococci.

In vitro Activity of Sparfloxacin (CI-978), a New Broad-Spectrum Fluoroquinolone

The in vitro activity of sparfloxacin (CI-978, AT-4140), a new fluoroquinolone, was compared with ciprofloxacin, norfloxacin and other commonly used antimicrobial agents against 650 strains of Enterobacteriaceae, 237 isolates of other gram-negative bacilli and 318 strains of gram-positive cocci. The MICs of sparfloxacin against 90% of the members of Enterobacteriaceae were between 0.12 and 0.5 microgram/ml. All the 48 isolates of notoriously drug-resistant Serratia marcescens were inhibited by less than 0.03-4.0 micrograms/ml of sparfloxacin. All the 90 isolates of Acinetobacter, 80 of the 88 strains of Pseudomonas aeruginosa and all the 28 isolates of Xanthomonas maltophilia were susceptible to sparfloxacin. The MIC90 for all the cocci tested ranged between 0.5 and 4.0 micrograms/ml of sparfloxacin. It inhibited 92% of enterococci as compared with 27% for ciprofloxacin and 22% for norfloxacin. It was better or comparable in activity to other fluoroquinolones and superior to penicillins, cephalosporins and aminoglycosides tested. There was cross-resistance between ciprofloxacin, norfloxacin and sparfloxacin.

Comparative activity of the new fluoroquinolone rufloxacin (MF 934) against clinical isolates of gram-negative and gram-positive bacteria

The antibacterial activity of the new fluoroquinolone rufloxacin (MF 934) was evaluated against 1095 clinical isolates and compared with that of other quinolones and various commonly used antibiotics. Rufloxacin was highly effective against members of theEnterobacteriaceae, inhibiting 98 % of the isolates at a concentration of 1 mg/l. Ninety-two percent ofAeromonas hydrophila and 65 %Acinetobacter strains tested were inhibited by 1 mg/l of rufloxacin, whereas 98 % of methicillin-susceptible and 87 % of methicillin-resistantStaphylococcus aureus strains and 76 % of coagulase-negative staphylococci strains required 4 mg/l for growth inhibition. The MIC values of rufloxacin for most bacteria were 4–16 times higher than those of ciprofloxacin and norfloxacin. Rufloxacin had little activity against xanthomonads, pseudomonads and enterococci. Approximately 95–96 % of isolates ofPseudomonas aeruginosa were inhibited by 2 mg/l of ciprofloxacin and norfloxacin as compared to 29 % inhibited by rufloxacin at this concentration.

Antibacterial Activity of the New Quinolone CI-960 (PD 127391) against Clinical Isolates at a Major Tertiary Care Center in Saudi Arabia

The antibacterial activity of the new fluoroquinolone CI-960 (PD 127391) was evaluated against 1,162 clinical isolates and compared with other quinolones and various commonly used antibiotics. CI-960 was highly effective against members of Enterobacteriaceae inhibiting 626 of the 629 isolates at a less than or equal to 0.03 to 0.12 microgram/ml concentration. All the 305 isolates of Pseudomonas aeruginosa, Xanthomona maltophilia, and Acinetobacter were susceptible to CI-960. It was the only effective drug against 10 multi-resistant isolates of pseudomonads and Acinetobacter. All staphylococci, including methicillin-resistant Staphylococcus aureus, were inhibited by less than or equal to 0.03-0.5 microgram/ml of CI-960. Like other drugs of its class, it had little activity against enterococci.

In vitro Activity of LY281389 and Comparison with Erythromycin and Oral Beta-Lactams

LY281389 is a new 14-member ring macrolide which is presently being developed for possible clinical use against bacterial infections. We compared the in vitro activity of LY281389 with erythromycin, ampicillin, augmentin and cephalexin against 610 clinical isolates. The new drug inhibited 97 and 11% of methicillin-sensitive and methicillin-resistant Staphylococcus aureus isolates, respectively, 59% of coagulase-negative staphylococci, 63% of enterococci and 74% of Haemophilus influenzae. All the 171 isolates of Streptococcus Lancefield group A, group B and Streptococcus pneumoniae were susceptible to LY281389 at MIC values ranging between 0.03 and 0.24 micrograms/ml. In vitro activity of LY281389 against the bacteria tested was comparable to that of erythromycin.

Antistaphylococcal and Antienterococcal Activity of the New Teicoplanin Amide Derivative MDL 62873

In vitro response of 469 clinical isolates of gram-positive cocci was tested against MDL 62873 by the agar dilution method. The bacteria consisted of 407 isolates of staphylococci and 62 strains of enterococci. In vitro activity of MDL 62873 was compared with that of ampicillin, augmentin, erythromycin and vancomycin. All the isolates were completely inhibited by MDL 62873 at an MIC ranging between 0.25 and 8.0 micrograms/ml. In vitro activity of this new amide derivative of teicoplanin was far superior to that of ampicillin, augmentin and erythromycin and equal to or slightly better than that of vancomycin.

In vitro Activity of Sparfloxacin against Salmonella typhi

Comparative in vitro activity of sparfloxacin was determined by the broth dilution method against 104 clinical isolates of Salmonella typhi. All of the isolates were inhibited by < or = 0.12 mg/l of this fluoroquinolone. Its inhibitory activity was slightly superior or comparable to that of other fluoroquinolones tested, namely ciprofloxain and norfloxain, and significantly greater than the conventional drugs, such as amikacin, ampicillin, Augmentin, ceftazidime, clindamycin, tetracycline and trimethoprim-sulfamethoxazole, used in the treatment of typhoid fever.

Anti-Salmonella activity of CP-99,219, a novel azabicyclo-naphthridone fluoroquinolone.

The antimicrobial activity of CP-99,219 was determined by the broth dilution method against 67 clinical isolates of Salmonella typhi. Ninety-one percent of the isolates were inhibited by < or = 0.12 mg/l of this quinolone, and all the 67 by 2.0 mg/l. Its inhibitory activity was slightly superior to ciprofloxacin and norfloxacin and significantly greater than ampicillin, augmentin, chloramphenicol and trimethoprim-sulphamethoxazole.

In vitro Activity of Isepamicin (Sch 21420), a New Aminoglycoside

The narrow therapeutic/toxic ratio of existing aminoglycosides has led to a search for safer drugs of this class. Isepamicin is a semi-synthetic aminoglycoside with a significantly low nephro as well as ototoxicity in animals and which is expected to have a clinical efficacy comparable to that of amikacin. We therefore compared its antibacterial activity with amikacin against 817 recent clinical isolates of gram-positive and gram-negative bacteria. The in vitro activity of isepamicin was comparable or slightly greater than amikacin against Staphylococcus aureus and most Enterobacteriaceae. However, it was significantly more inhibitory towards Serratia marcescens, Enterobacter and Klebsiella pneumoniae.

Antibacterial Activity of FCE 22101 against Relatively Resistant Blood Culture Isolates

In vitro antibacterial activity of the new penem FCE 22101 was tested against blood culture isolates from 1,374 consecutive patients in a major tertiary care referral center in Saudi Arabia. Many of the isolates were significantly more resistant to commonly used beta lactams. Of the 809 members of Enterobacteriaceae tested all but 14 isolates of Enterobacter were susceptible to FCE 22101 with an MIC range of 0.12-8.0 micrograms/ml. It inhibited all the 183 isolates of Staphylococcus aureus, both methicillin-sensitive and methicillin-resistant. Ninety percent of coagulase-negative staphylococci and enterococci were susceptible to this new penem. All isolates of Acinetobacter, CDC group VE-2 and Brucella melitensis from blood were inhibited by FCE 22101. However, it was ineffective against pseudomonads. Of the nine other beta lactam drugs tested for comparison, only imipenem was found to be more inhibitory, at lower MIC values, than FCE 22101.