Activity Of Cefaclor Research Articles

Comparison of E Test and Agar Dilution Methods for Determining Antibiotic Susceptibilities of Anaerobic Bacteria and Viridans Streptococci Isolated from Blood

The antimicrobial susceptibilities of 311 strains of anaerobic bacteria and 140 strains of aerobic bacteria, isolated from blood after dental extraction, were determined by the E test and compared with the results obtained by the agar dilution method on PDM-ASM 2 agar. E test MICs agreed within ±1 dilution step to the agar dilution MICs in 93%, 52%, 90%, 94% of the tested anaerobes for penicillin V, cefaclor, clindamycin and erythromycin, respectively. For aerobic bacteria the agreement was ≥ 90% for the antibiotics tested.Thein vitroactivities of penicillin V, clindamycin and erythromycin were higher than the activity of cefaclor against the majority of bacteria tested.

Cefaclor: A Contemporary Look at Susceptibility of Key Pathogens from Around the Globe

The orally administered cephalosporin antibiotic, cefaclor, has been available for clinical use in many countries since 1979. Because widespread antibiotic use is often cited as a factor in the emergence of bacterial resistance to antibiotics, we sought to determine the degrees of resistance to cefaclor expressed by key pathogens recently isolated in 10 countries widely distributed around the world. Using the E-test ®, minimal inhibitory concentrations (MIC) were determined for cefaclor and several comparator antibiotics against approximately 700 fresh clinical isolates of each of six bacterial species. The results demonstrated that > 90% of Haemophilus influenzae (β-lactamase producing and non-producing), Haemophilus parainfluenzae (β-lactamase producing and non-producing), Moraxella catarrhalis (> 90% β-lactamase producing), and methicillin-susceptible Staphylococcus aureus, and 85% of Escherichia coli were susceptible to cefaclor at the NCCLS interpretive breakpoints. MIC distributions showed that there has been no change in the activity of cefaclor against penicillin-susceptible strains of Streptococcus pneumoniae since 1977.

Susceptibility of Haemophilus influenzae isolates with known resistance mechanisms to five cephalosporins.

The in vitro activities of cefaclor, cefetamet, cefixime, cefotaxime and cefuroxime were determined against 150 isolates of Haemophilus influenzae. These included 50 ampicillin-susceptible, 50 beta-lactamase-producing and 50 intrinsically ampicillin-resistant isolates. A closer relationship was apparent between the intrinsic resistance to ampicillin and reduced susceptibility to cephalosporins. Both MIC and disc diffusion methods showed that the activities of cephalosporins were reduced against most, though not all, isolates with intrinsic resistance to ampicillin. All intrinsically ampicillin-resistant isolates should be considered resistant to all cephalosporins at the present time since the clinical significance of the reduction in susceptibility is uncertain. Amongst the five cephalosporins tested, cefaclor susceptibility may facilitate the detection of intrinsic ampicillin resistance since it predicts isolates with this type of resistance mechanism.

Comparative antibacterial activity of the new cephalosporin cefcanel against anaerobic bacteria

The activity of cefcanel against anaerobic cocci, Clostridium perfringens, Bacteroides fragilis, Bacteroides spp. and fusobacteria was determined by the agar dilution method and compared with the activity of cefaclor, cephalexin, cefadroxil, phenoxymethylpenicillin and ampicillin. Cefcanel showed good activity against Clostridium perfringens, Bacteroides spp. and fusobacteria (MIC90 = 1-4 mg/l). Against anaerobic cocci its MIC90 value was 16 mg/l, and against Bacteroides fragilis, 32 mg/l. Cefcanel has an antibacterial activity that warrants investigation in clinical trials.

Effect of refrigerated storage on cefaclor in Mueller-Hinton agar.

Cefaclor is less stable than most cephalosporins in media at 35 degrees C. We demonstrated that the activity of cefaclor in Mueller-Hinton agar diminishes continuously at 4 degrees C, resulting in a loss of two-thirds of the activity within 21 days. We recommend that agar dilution plates for this cephalosporin be prepared on the day of their use.

In vitro activity of cefaclor against haemophilus influenzae in comparison to cephalexin, cephradine, cefadroxil, cefatrizine and ampicillin

The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of cefaclor were compared with those of cephalexin, cephradine, cefadroxil, cefatrizine, and ampicillin for 50 strains ofHaemophilus influenzae. The activity of cefaclor and cefatrizine was 8–16 times higher than that of the other cephalosporins and 1/8 that of ampicillin. Cross-resistance between ampicillin and the cephalosporins tested was observed for one strain which did not produce beta-lactamase. No cross-resistance was found for beta-lactamase-producing strains. The killing kinetics of 4 mg/l cefaclor did not differ in two ampicillin-sensitive strains and one beta-lactamase-producing strain which was slightly resistant to ampicillin. The survival rate varied from 10% to 1% after six to seven hours.

Antimicrobial activity in vitro of cefaclor, a new oral cephalosporin.

The antimicrobial activity of cefaclor, a new orally administered cephalosporin derivative, was studied in vitro against a variety of Gram-positive and Gram-negative clinical isolates. Both penicillin-resistant and penicillin-susceptible strains of Staphylococcus aureus were susceptible to cefaclor, with mean MICs of 1.44 and 0.93 microgram/ml, respectively. However, the MBC for penicillin-resistant S. aureus was higher than that for the penicillin-susceptible strains. All strains of Streptococcus pyogenes, Streptococcus viridans, and Streptococcus pneumoniae tested were highly susceptible to cefaclor; all strains of Streptococcus faecalis were highly resistant to cefaclor. Strains of Escherichia coli, Klebsiella sp., Proteus mirabilis, and Hemophilus influenzae were susceptible to cefaclor. Eighty per cent of strains of H. influenzae were inhibited by 5 micrograms/ml of cefaclor. Most strains of Enterobacter sp., indole-positive Proteus, Pseudomonas sp., and Serratia sp. were resistant to cefaclor.