Association between Type A blaZ Gene Polymorphism and Cefazolin Inoculum Effect in Methicillin-Susceptible Staphylococcus aureus.

Prevalence of blaZ gene types and the inoculum effect with cefazolin among bloodstream isolates of methicillin-susceptible Staphylococcus aureus.

We sought to define the prevalence of blaZ gene types and the inoculum effect to cefazolin among methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. The blaZ gene was present in 142/185 (77%) isolates. A total of 50 (27%) isolates had a ≥4-fold increase in the cefazolin MIC from a standard to a high inoculum, and 8 (4%) demonstrated a nonsusceptible cefazolin MIC, all t...

Cefazolin plus Clavulanic Acid Overcomes the Inoculum Effect in a Methicillin-Susceptible Staphylococcus aureus (MSSA) Rat Endocarditis Model

In Vivo Effects of Cefazolin, Daptomycin, and Nafcillin in Experimental Endocarditis with a Methicillin-Susceptible Staphylococcus aureus Strain Showing an Inoculum Effect against Cefazolin.

Several reports have implicated the inoculum effect that some strains of type A beta-lactamase (Bla)-producing, methicillin-susceptible Staphylococcus aureus (MSSA) show against cefazolin as the cause for clinical failures in certain serious deep-seated infections. Here, using a previously reported MSSA strain displaying this phenotype (TX0117), we obtained a Bla-cured derivative (TX0117c) with...

Antibiotic Resistance Pattern and Frequency of mecA Gene in Staphylococcus aureus Isolated from Shohada Hospital, Tabriz

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious and life-threatening hospital- and community-acquired infections. Colonized and infected patients represent the most important reservoir of MRSA in health care facilities. Therefore, in this study, MRSA isolates collected from Shohada Hospital in Tabriz were evaluated for the frequency of mecA gene and their anti...

Association of borderline oxacillin-susceptible strains of Staphylococcus aureus with surgical wound infections.

Staphylococcus aureus isolates which produce type A staphylococcal beta-lactamase have been associated with wound infections complicating the use of cefazolin prophylaxis in surgery. To further evaluate this finding, 215 wound isolates from 14 cities in the United States were characterized by antimicrobial susceptibility and beta-lactamase type and correlated with the preoperative prophylactic ...