Background:Carbapenems are effective against severe Pseudomonas aeruginosa nosocomial infections.Therefore,carbapenem-resistant Pseudomonas aeruginosa is a serious public health threat.An understanding of the risk of inappropriate exposure to different antimicrobials in resistant Pseudomonas aeruginosa infection could help in elucidating the effective approach towards using antimicrobials in vulnerable patients with CRPA infection.Object:To investigate the association between exposure of β-lactam antimicrobials and CRPA infection relative to control patients.Methods:The MEDLINE/PubMed and OVID/Embase databases were used to search case-control and cohort stud-ies in English language which reported antimicrobial exposure as risk factors for CRPA infection.The pooled odds ratios(OR)were calculated using a random-effect and fixed-effect model,and forest plots from a cumula-tive meta-analysis method were used to better show how pooled OR changed as updated evidence accumulated.Results:A total of 24 studies comprising 7 039 participants were included for cumulative meta-analysis.A posi-tive correlation was found between development of CRPA infection and exposure of beta-lactam antimicrobials:carbapenems(OR=7.60,95％CI:3.95 to 14.62,P＜0.0001),imipenem(OR=9.81,95％CI:5.56 to 17.33),ampi-cillin(OR=1.86,95％CI:1.14 to 2.41),piperacillin(OR=2.82,95％CI:1.46 to 2.43),penicillins(OR=1.42,95％CI:0.90 to 2.24),cephalosporins(OR=1.88,95％CI:1.46 to 2.43)and β lactamase inhibitors(OR=1.96,95％CI:1.44 to 2.67).Further,exposure of other antimicrobial agents like quinolone(OR=2.35,95％CI:1.78 to 3.10),ciprofloxacin(OR=2.35,95％CI:1.66 to 3.95),aminoglycoside(OR=2.17,95％CI:1.60 to 2.95),amikacin(OR=3.11,95％CI:2.10 to 4.61),glycopeptides(OR=3.02,95％CI:1.92 to 4.75)and vancomycin(OR=3.26,95％CI:1.48 to 7.18),were also found to be positively associated with development of CRPA infec-tion.Conclusions:Exposure of all kinds of β-lactams is significantly associated with development of carbapenem-resistant Pseudomonas aeruginosa infection.These findings provide an impetus to take a more active approach while using β-lactam antimicrobials in patients with resistant Pseudomonas aeruginosa infections.