Clinical Outcomes Associated with Biofilm-Related Bacterial Infections
Methods: A convenience sample of 187 unique clinical isolates from 144 patients collected from 2005 to 2012 was studied. 48h static biofilms were assessed by the microtiter plate method with crystal violet staining. Clinical information including demographics, comorbidities, antibiotic usage and clinical outcomes was determined retrospectively, and associations with BFI were determined by univariate analysis (SPSS v19.0).
Results: Patients were primarily male (82%) military members (65%) with combat trauma (56%). Of the 113 (60%) BFI, 5 were MSSA, 14 MRSA, 32 Klebsiella pneumoniae (KP), 5 Escherichia coli (EC), 29 Acinetobacter baumannii complex (ABC), and 28 Pseudomonas aeruginosa (PA). There were 1 MSSA, 2 MRSA, 12 KP, 29 EC, 24 ABC, and 6 PA among 74 non-BFI. BFI were more frequent among MRSA (p = 0.021) and PA (p = 0.004), and less common among EC (p < 0.001). 80 BFI and 34 non-BFI were recovered from wounds (71% vs. 46%, p<0.01), 10 BFI and 1 non-BFI were recovered from respiratory cultures (9% vs. 1%, p=0.03), 3 BFI and 18 non-BFI were recovered from urine (3% vs. 24%, p <0.01), 20 BFI and 21 non-BFI were recovered from blood (18% vs. 28%, p = 0.08). BFI were not associated with Foley, orthopedic devices or venous catheters. Diabetes was more common in the non-BFI group (p = 0.026). Non-significant variables included CAD, CKD/ESRD, burn/%TBSA, infection vs. colonization, polymicrobial infection, antibiotic exposure, number of surgeries, proportion cured, persistent infection and mortality. 30 of 131 infecting isolates, (19 BFI), were associated with persistent infection, and compared to cured infections, had more MSSA (17% vs 1%, p = 0.002) and PA (23% vs 9%, p = 0.034), and higher median %TBSA burned (77% vs 53.5%, p <0.01). Wound isolates were more often cured than became persistent (68% vs 27%, p <0.01).
Conclusion: BFI were more commonly MRSA and PA, and observed in wound and respiratory cultures. BFI and non-BFI had similar infectious outcomes.
C. J. Sanchez Jr., None
M. L. Beckius, None
J. Wenke, None
C. K. Murray, None
K. S. Akers, None