Conclusion: The recommended doses of cefazolin are probably insufficient in ARC patients with MSSA respiratory infections with high inoculum effect.
Besides, the risk of treatment failure may be exacerbated when using antibiotics exposed to the inoculum effect [27], as are most beta-lactams.
Firstly, in vitro/in vivo studies [27] suggested that Pip–Taz seems to be less resistant to the inoculum effect comparing to carbapenems.
When colonization pressure with resistant strains is above a certain level, the risk of cross-transmission becomes extremely high and very difficult to overcome (inoculum effect) [8].
The marked inoculum effect observed with tazobactam in ESBL-PE may contribute to explain why in vitro susceptibility does not systematically translate to clinical efficacy [58].
In clinical analysis, the rate of therapeutic failure was 36% (4 11), with a strong association with inoculum effect (p = 0.02).
There was a strong association between therapeutic failure, CrCL > 200 ml min and PK PD target non-attainment adjusted on the inoculum effect (p = 0.04).
Although recommended dosing regimen (100 mg kg day continuously) may be suitable for MSSA infections despite high inoculum effect, evidence in patients with augmented renal clearance (ARC) is still limited.
Introduction: In methicillin-susceptible staphylococcus aureus (MSSA) infections, several studies have previously suggested that a pronounced inoculum effect could significantly increase MIC for cefazolin, potentially leading to higher therapeutic failure rates.
