title: Increased therapeutic efficacy of combination of azithromycin and ceftazidime on Pseudomonas aeruginosa biofilm in an animal model of ureteral stent infection.
abstract: Infection caused by ureteral stent indwelling is one of the most difficult medical problems, since once bacteria reside in biofilms they are extremely resistant to antibiotics as well as to the host immune defences. In this study we assessed the in vitro and in vivo efficacy of azithromycin and ceftazidime in preventing ureteral stent infection by Pseudomonas aeruginosa.
  
  
  
  The susceptibility testing with adherent bacteria showed that the biofilm was strongly inhibited by azithromycin treatment, ceftazidime against adherent bacteria in the presence of azithromycin showed the minimum inhibitory concentrations (MICs) and minimum bacteriocidal concentrations (MBCs) dramatically lower than those obtained in the absence of azithromycin. Moreover, ceftazidime plus azithromycin reduced twitching motility and production of rhamnolipid. For the single-treatment groups, in vivo intravenous injection of ceftazidime showed the highest inhibitory effect on bacterial load. Azithromycin prophylactic injection combined with ceftazidime showed increased inhibitory effect on bacterial load than that of each single antibiotic.
  
  
  
  Combination of azithromycin and ceftazidime effectively prevent the formation of biofilm and reduced bacteria load of Pseudomonas aeruginosa compared to separate treatment of either of these two antibiotics. This combined treatment option have the potential to contribute to the success of Pseudomonas biofilm elimination in the clinical environment.
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Xing
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Guanying
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Pharmacy, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042, China. chenjh-110@263.net.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D017963:Azithromycin / Q000008:administration & dosage*; D018441:Biofilms / Q000187:drug effects*; D002442:Ceftazidime / Q000008:administration & dosage*; D004195:Disease Models, Animal; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008826:Microbial Sensitivity Tests; D016459:Prosthesis-Related Infections / Q000188:drug therapy* / Q000382:microbiology; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D015607:Stents / Q000009:adverse effects*
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin; D002442:Ceftazidime
keywords: Azithromycin; Bacterial biofilm; Ceftazidime; Ureteral stent infection