title: A retrospective analysis of carbapenem-resistant Acinetobacter baumannii-mediated nosocomial pneumonia and the in vitro therapeutic benefit of cefoperazone/sulbactam.
abstract: BACKGROUND
  Acinetobacter baumannii has been reported increasingly as a significant causative organism of various nosocomial infections, including hospital-acquired pneumonia (HAP). The aim of this study was to investigate the clinical characteristics of HAP induced by carbapenem-resistant A. baumannii (CRAB) in elderly patients and the in vitro antimicrobial effects of cefoperazone/sulbactam combination therapy.
  
  
  METHODS
  Seventy-one elderly patients in the geriatric ward of the General Hospital of the People's Liberation Army (PLAGH) with CRAB-induced HAP were analyzed retrospectively. The checkerboard method was used to determine the in vitro drug sensitivity of 60 CRAB strains to antimicrobial combinations (cefoperazone/sulbactam with meropenem, minocycline, or levofloxacin). The occurrence of carbapenemase genes was detected by PCR.
  
  
  RESULTS
  CRAB-induced HAP occurred mostly in patients with underlying diseases. Prior to onset, most patients had received antimicrobial therapies including broad-spectrum β-lactams, invasive mechanical ventilation, and catheterization. The 30-day survival rate was 95.1% in patients using cefoperazone/sulbactam, with or without combination with antimicrobial drugs, and 73.3% in patients not using cefoperazone/sulbactam (p<0.05). When cefoperazone/sulbactam was used in combination with minocycline, levofloxacin, and meropenem, minimum inhibitory concentrations MIC50 and MIC90 were reduced for each drug. The genes OXA-23 and OXA-51 were amplified in 96.7% of the strains, but the genes OXA-24, OXA-58, SIM, VIM, and IMP were not amplified.
  
  
  CONCLUSIONS
  CRAB-induced HAP occurred mostly in patients with anemia or decreased levels of serum albumin, but with elevated levels of C-reactive protein and creatinine. Cefoperazone/sulbactam in combination with minocycline, meropenem, and levofloxacin had a synergistic and additive in vitro bacteriostatic action on CRAB.
authors.affiliation: Nanlou Respiratory Diseases Department, Chinese PLA General Hospital, 28 Fuxing Rd, Beijing 100853, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Xia
authors.affiliation: Nanlou Respiratory Diseases Department, Chinese PLA General Hospital, 28 Fuxing Rd, Beijing 100853, China.
authors.forename: Duchao
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Nanlou Clinical Laboratory Department, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Nanlou Clinical Laboratory Department, Chinese PLA General Hospital, Beijing, China.
authors.forename: Meiliang
authors.initials: M
authors.lastname: Gong
authors.affiliation: Nanlou Clinical Laboratory Department, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Nanlou Respiratory Diseases Department, Chinese PLA General Hospital, 28 Fuxing Rd, Beijing 100853, China. Electronic address: fangxq301@126.com.
authors.forename: Xiangqun
authors.initials: X
authors.lastname: Fang
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002097:C-Reactive Protein / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology*; D002438:Cefoperazone / Q000627:therapeutic use*; D003428:Cross Infection / Q000188:drug therapy*; D004338:Drug Combinations; D024901:Drug Resistance, Multiple, Bacterial; D004357:Drug Synergism; D005260:Female; D006801:Humans; D064704:Levofloxacin / Q000627:therapeutic use; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008911:Minocycline / Q000627:therapeutic use; D018410:Pneumonia, Bacterial / Q000188:drug therapy*; D012189:Retrospective Studies; D013407:Sulbactam / Q000627:therapeutic use*; D013845:Thienamycins / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D004338:Drug Combinations; D013845:Thienamycins; D064704:Levofloxacin; D002438:Cefoperazone; D002097:C-Reactive Protein; D000077731:Meropenem; D008911:Minocycline; D013407:Sulbactam
keywords: Acinetobacter baumannii; Carbapenem; Combined drug sensitivity test; Hospital-acquired pneumonia