Conclusion: There was active efflux of tetracycline and penicillin in clinical isolated strains of Escherichia coli, but the capability was less than in Mar strains.

• 结论：临床分离的敏感株中亦存在能泵出四环素和青霉素的主动外排系统,但其外排功能显著低于多重耐药株。