Comparing Traditional Culture Methods and New Molecular Testing Techniques to Analyze Biofilm Composition on Uninfected IPPs

Transcription

1 Comparing Traditional Culture Methods and New Molecular Testing Techniques to Analyze Biofilm Composition on Uninfected IPPs Martin S. Gross 1, Gerard D. Henry 2 1: Dartmouth-Hitchcock Medical Center; 2: Regional Urology

2 Biofilm Protective coating formed by bacteria Allows for increased survival Occasional planktonic release Potential source of IPP infection Henry GD et al. J Urol 2004.

3 Biofilm Detection Traditional Microbiological Culture Swab of device and tissue excision Bacterial growth in culture Identification and sensitivity Larsen LH et al. J Med Microbiol 2012.

4 Biofilm Detection Advantages Widespread availability Cost effectiveness Local antibiogram sensitivities Proven historic efficacy Disadvantages Specimen collection requirements Time duration (bacterial growth) Poor delineation of multiple organisms Difficulty culturing anaerobic bacteria

5 Biofilm Detection Molecular analysis PCR amplification of 16S rdna Identification and sequencing Known bacterial taxonomies Lévy PY et al. Clin Microbiol Infect 2012.

6 Biofilm Detection Advantages Increased sensitivity Increased efficacy in biofilm analysis Antibiotic sensitivity data Relative ease of anaerobic culture Disadvantages Specimen collection requirements Time duration (shipment and processing) Clinical relevance of bacteria Increased cost

7 Objectives Compare biofilm analysis from clinically uninfected inflatable penile prostheses at removal and replacement for mechanical failure Traditional culture methods and16s ribosomal DNA testing used

8 Methods Specimens: 11 clinically uninfected AMS IPPs during removal/replacement IPP Duration Mean 39 months Range 4 months to 12 years Patient Age 64 years 51-76

9 Methods All received IV cefazolin and gentamicin Device swabbed at capsule entry Thorough washout performed Pre- and post-washout tissue excised

10 Results Microbiological Culture Ten of 11 prostheses had negative aerobic, anaerobic, acid-fast, and fungal cultures One culture report showed pan-sensitive s. lugdunensis in very small numbers, with negative molecular testing

11 Results 16S rdna Molecular Analysis Two of 11 prostheses had positive results First specimen had 13 separate bacteria, with 4 known prosthetic infectious pathogens present Only 2 of these infectious bacteria were susceptible to our IV antibiotic regimen

12 Results 16S rdna Molecular Analysis Two of 11 prostheses had positive results Second specimen had 9 separate bacteria, with 3 known prosthetic infectious pathogens present None of these infectious bacteria were susceptible to our IV antibiotic regimen

13 Study Limitations Small amount of specimens Inherent patient factors unknown Limited follow-up

14 Conclusions Molecular testing yielded biofilm information that was not reported by conventional culture methods Some bacteria identified by molecular testing were known prosthetic pathogens

15 Conclusions 71% of these pathogens showed poor susceptibility to our typical IV antibiotic regimen Further research on biofilm needed

16 References Henry GD et al. Penile prosthesis cultures during revision surgery: a multicenter study. J Urol 2004; 172: 153. Henry GD et al. Revision washout decreases penile prosthesis infection in revision surgery: A multicenter study. J Urol 2005; 173: 89. Larsen LH, Lange J, Xu Y et al. Optimizing culture methods for diagnosis of prosthetic joint infections: a summary of modifications and improvements reported since J Med Microbiol. 2012; 61: 309. Lévy PY, Fenollar F. The role of molecular diagnostics in implantassociated bone and joint infection. Clin Microbiol Infect 2012; 18: Wilson SK et al. Inflatable penile implant infection: predisposing factors and treatment suggestions. J Urol 1995; 153: 659.