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Biomedical subjects

J C Lucet

Publications and source records attributed to J C Lucet.

40 records · Page 3Linked to original sources
PubMed1991

Resistance of Staphylococcus aureus recovered from infected foreign body in vivo to killing by antimicrobials.

Because persistence of infections associated with prosthetic material despite the use of appropriate antibiotics is a major clinical problem, the antimicrobial susceptibility of bacteria responsible for a chronic subcutaneous tissue cage infection in rat was investigated ex vivo. Three to 6 weeks after the initiation of infection, suspensions of two strains of Staphylococcus aureus recovered from the foreign body surface and surrounding fluid were exposed to either oxacillin, vancomycin, fleroxacin, gentamicin, or rifampin. The MBCs of these bacteria were markedly elevated, in most cases 128 to greater than 256 times higher than the MBC of batch culture S. aureus in either logarithmic or stationary phase. Kinetic studies showed the bacteria did not grow when incubated for 2 h in Mueller-Hinton broth, possibly reflecting dormancy. Their killing was slow and incomplete by all antibiotics at greater than 8 times their MIC. These data provide direct evidence of a decreased susceptibility of S. aureus to the killing effect of antimicrobials during chronic foreign body infections in vivo.

Animals↗
PubMed1990

Treatment of experimental foreign body infection caused by methicillin-resistant Staphylococcus aureus.

A novel model of experimental foreign body infection was developed in rats: four perforated Teflon tissue cages per animal were implanted subcutaneously and 3 to 4 weeks later were infected with 0.5 x 10(5) to 2 x 10(5) CFU of methicillin-resistant Staphylococcus aureus. After 2 weeks, the number of CFU in the cage fluid was determined [day 1 mean, (7.25 +/- 0.79) log10 CFU/ml], and treatment with vancomycin (50 mg/kg twice a day [BID]), fleroxacin (50 mg/kg BID), or fifampin (25 mg/kg BID), alone and in combination, was initiated for a duration of 6 days. Concentrations of antibiotics in cage fluids were in the range of those encountered in clinical conditions. Eighteen hours after the last injection (day 7), the number of CFU in the cage fluid was determined and the difference between day 1 and day 7 values was calculated. Rifampin, alone and in combination with fleroxacin or vancomycin, was the most effective regimen in reducing the bacterial counts in the tissue cage fluids [(1.87 +/- 1.44, 2.18 +/- 1.02, and 2.55 +/- 1.09 log10) CFU/ml, P less than 0.001, respectively]. After treatment, cage fluids and cages were analyzed for resistant bacteria. Resistance to rifampin occurred in 15 of 19 cages in animals treated with rifampin alone and in 4 of 25 in animals treated with rifampin plus vancomycin. We detected no development of resistance to rifampin in animals treated with rifampin plus fleroxacin or to fleroxacin in animals treated with this antimicrobial agent. In conclusion, regimens including rifampin alone or in combination with vancomycin or fleroxacin were an effective treatment of foreign body infection due to methicillin-resistant S. aureus in reducing bacteria counts, but rifampin monotherapy was compromised by significant emergence of resistance. The combined therapy of fleroxacin with rifampin prevent development of resistance to rifampin.

Animals↗