Antibiotic Cycling Regimens
Antibiotic cycling regimens are prescription policies that suspend the use of a particular antibiotic for a period (“cycle”) to allow resistances levels to subside. This should prevent resistance from building up in the microbial ecosystem. Antibiotic cycling regimens are typically employed in intensive care units where resistance is often rampant.
While antibiotic cycling may yet be proven to be a good idea, only some weak evidence shows that it has any effect. Several studies found that the effect of cycling can range from moderately slowing the rate at which resistance builds up to having detrimental effects.1 It becomes obvious that the same policy may not work for all antibiotics, that cycle parameters need further investigation to find effective combinations and that the potential adverse effects of cycling are relatively unknown.
The microbial ecosystems that cycling aims to disrupt, are rarely known or understood and no real-time feedback mechanisms exist for appropriate adjustments to be made to regimens. Antibiotic resistance stems from specific genes that bacteria carry that can travel (“horizontally”) between organisms and between patients in complex ecosystems that are highly localised. To be more effective, cycling policies need to be guided by the real-time monitoring of the genetics of the local bacterial ecosystem.
Simultaneous resistance to multiple antibiotic therapies (as is often observed in intensive care) is proof that the invisible microbial ecosystems are important for the design of effective cycling regimens. It is well established that effective cycling can reduce antibiotic resistance load and improve patient safety and lead to responsible stewardship of antibiotics.
1. Bal A, Kumar A, Gould I. Antibiotic heterogeneity: from concept to practice. Annals of the New York Academy of Sciences 2010;1213:81-91.