In vitro Activities of Oral Cephem and Telithromycin Against Clinical Isolates of Major Respiratory Pathogens in Japan

Abstract

The in vitro antibacterial activities of oral cephem antibiotics and ketolide telithromycin against major respiratory pathogens possessing β-lactam-resistant mutations (within the pbp gene) and/or macrolide-resistant genes (erm and mef) were examined in clinical isolates collected at 66 institutes in all over the Japan between 2002 and 2003. Telithromycin showed the strongest antibacterial activity against methicillin-susceptible Staphylococcus aureus strains with and without macrolide-resistant genes, such as ermA or ermC gene. All the cephem antibiotics showed potent antibacterial activity against Streptococcus pyogenes, with minimum inhibitory concentrations (MICs) of 0.015 mg/L or lower. Cefdinir had a much higher MIC90 against genotypic penicillin-resistant Streptococcus pneumoniae (gPRSP) than cefditoren and cefcapene (8 mg/L cefdinir vs. 1 mg/L cefditoren and cefcapene). The majority of gPRSP harbored either ermB or mefA, and the antibacterial activity of telithromycin against these strains was decreased however some susceptibility was still sustained. Cefditoren exerted the strongest antibacterial activity against β-lactamase-negative ampicillin-resistant Haemophilus influenzae, with an MIC90 of 0.5 mg/L. These results underline the importance of checking the susceptibility and selecting an appropriate antibiotic against target pathogens.

Molecular docking and molecular dynamics studies on β-lactamases and penicillin binding proteins

“…Cephalosporins have a broad spectrum of activity against Gram negative and Gram positive organisms such as Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, Klebsiella pneumoniae and Staphylococcus aureus. [16][17][18][19][20][21] S. aureus and S. pneumoniae are leading causes of hospital and community acquired bacterial infection and they are a global health threat. 22,23 However, many community based infections are becoming more difficult to treat owing to the emergence of resistant organisms such as multidrug-resistant S. pneumoniae (MDRSP) and methicillin-resistant S. aureus (MRSA).…”