Table 2

PEx characteristics and treatments received

fT>MIC sufficient (n=14)fT>MIC not sufficient (n=13)P value
Pulmonary function at exacerbation,* predicted mean (SE)(n=12 with PFTs)(n=11 with PFTs)
 % predicted FEV176.7 (6.29)87.2 (6.74)0.296
 % predicted FVC82.2 (7.00)93.7 (7.50)0.368
 % predicted FEF25–7577.9 (11.43)67.3 (10.68)0.588
Bacterial and viral pathogens
 MRSA positive,‡ n (% yes)1 (7)2 (15)0.496
 MSSA positive,‡ n (% yes)3 (21)1 (8)0.315
Pseudomonas aeruginosa positive,‡ n (% yes)4 (29)5 (38)0.586
Achromobacter xylosoxidans positive,‡ n (% yes)1 (7)0 (0)0.326
Stenotrophomonas maltophilia positive,‡ n (% yes)1 (7)0 (0)0.326
Haemophilus influenzae positive,‡ n (% yes)1 (7)0 (0)0.290
 No pathogen present,‡ n, (% yes)7 (50)5 (38)0.547
Respiratory pathogen panel‡(n=6 tested)(n=5 tested)
 Rhino/enterovirus (n)210.999
 Negative (n)44
PEx treatments
 Primary beta-lactam antibiotic,‡ n (%)0.124
  Ceftriaxone2 (14)0 (0)
  Ceftazidime8 (57)4 (31)
  Cefepime1 (7)4 (31)
  Piperacillin–tazobactam1 (7)4 (31)
  Meropenem2 (14)1 (8)
Narrow spectrum,‡ n (% yes)11 (79)8 (62)0.333
Concurrent aminoglycosides,‡ n (% yes)8 (57)9 (69)0.516
Concurrent MRSA-directed therapy,‡ n (% yes)3 (21)2 (15)0.686
Total days of antibiotic therapy,* predicted mean (SE)18.2 (1.57)13.4 (1.66)0.086
Steroids given,‡ n (% yes)5 (36)8 (62)0.180
fT>MIC,* mean (SE)87.5 (6.4)28.2 (6.8)<0.001
Creatinine clearance,§* mean (SE)148.1 (15.8)224.9 (16.7)0.002
  • *General linear model with Gaussian family and identity link, controlling for demographic characteristics.

  • †Square transform.

  • ‡χ2.

  • §Log transform.

  • FEF25–75, forced expiratory flow 25–75; FEV1, forced expiratory volume in one second; fT>MIC, time above the minimum inhibitory concentration; FVC, forced vital capacity; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-sensitive Staphylococcus aureus; PEx, pulmonary exacerbation; PFT, pulmonary function test.