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In vitro activity of HR 756, a new cephalosporin compound
Abstract:
The in vitro activity of HR 756, a new cephalosporin, has been determined against recent clinical isolates and compared with that of other beta-lactam antibiotics. The geometric means of the minimum inhibitory concentrations (MIC) for different isolates of Escherichia coli (100 isolates), Klebsiella pneumoniae (84), Pseudomonas aeruginosa (121), Proteus mirabilis (52), indole-positive Proteus species (9), Salmonella species (19), Staphylococcus aureus penicillin-sensitive (29) and penicillin-resistant (39) were: 0.095, 0.124, 11.1, 0.095, 0.0107, 0.078, 1 and 0.95 mcg/ml, respectively. Its activity was affected by rise in inoculum against S. aureus and P. aeruginosa but not against K. pneumoniae and E. coli. Bactericidal activity was determined by membrane filtration method. HR 756 was found to be bactericidal to E. coli, K. pneumoniae, P. aeruginosa and Proteus species. Although the MICs of the tested S. aureus strains were 1 mcg/ml, 5 mcg/ml of HR 756 failed to kill 99% of the inoculum within 24 hours.
Insights
HR 756, a novel cephalosporin, demonstrates potent in vitro antibacterial activity against key Gram-negative pathogens like Escherichia coli and Klebsiella pneumoniae, showing bactericidal effects. Its efficacy against Staphylococcus aureus warrants further investigation.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Antibiotic resistance necessitates the development of new antimicrobial agents.
- Cephalosporins are a critical class of beta-lactam antibiotics used to treat bacterial infections.
Purpose of the Study:
- To evaluate the in vitro antibacterial activity of HR 756 against recent clinical isolates.
- To compare the efficacy of HR 756 with other beta-lactam antibiotics.
- To determine the bactericidal activity of HR 756.
Main Methods:
- Minimum Inhibitory Concentrations (MICs) were determined for various bacterial species.
- Inoculum effect on HR 756 activity was assessed.
- Bactericidal activity was evaluated using the membrane filtration method.
Main Results:
- HR 756 exhibited potent activity against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, indole-positive Proteus, and Salmonella species.
- Geometric mean MICs ranged from 0.0107 to 0.124 mcg/ml for susceptible Gram-negative bacteria.
- HR 756 demonstrated bactericidal activity against E. coli, K. pneumoniae, P. aeruginosa, and Proteus species, but failed to eradicate S. aureus at 5 mcg/ml.
Conclusions:
- HR 756 shows promising in vitro activity against a range of Gram-negative bacteria.
- The new cephalosporin is bactericidal to several key pathogens.
- Further studies are needed to clarify the activity of HR 756 against Staphylococcus aureus.