Reference	Objective	Design	Evidence
Allewelt et al. [447]	Ampicillin/sulbactam vs. clindamycin + cephalosporin	RCT	2B−
Bartlett and Gorbach [448]	Penicillin G vs. clindamycin in anaerobic infection	RCT	3B+
El Solh et al. [6]	BAL study of microbiology of NH patients	PCS	4A+
Fernandez Sabe et al. [449]	Co‐amoxiclav in anerobic infection	PCS	3B+
Gudiol et al. [450]	Clindamycin vs. penicillin	RCT	2B+
Kadowaki et al. [442]	Ampiciilin/sulbactam vs. clindamycin vs. panipenem/betamiprom	RCT	2B−
Leroy et al. [44]	Study of ICU admissions	PCS	4B+
Mier et al. [443]	PSB study of ICU admissions	PCS	3B+
Ott et al. [452]	Comparison of moxifloxacin vs. ampicillin/sulbactam	RCT	2C−
Perlino [451]	Clindamycin vs. metronidazole	RCT	3B−