Immediate joint infection diagnosis using bed-side iPhone live imaging

ABSTRACT

Introduction and Aims:
Joint infections are morbid, costly and most importantly, difficult to diagnose especially in the rural/remote general practice setting. We propose a system of simple optical beads attached to an iPhone to immediately identify live bacteria with a single drop of joint aspirate. 

Hypothesis: 
The iPhone-optical bead system through live-stains will identify live bacteria promptly and of clinically-relevant significance; decision to proceed to theatre/emergency decompression/transfer. 

Measurable Outcomes:
1) Time to treat (locally/transfer)
2) Morbidity
3) Mortality

Study Design: 
A cohort prospective pilot 

Methods: 
To establish sensitivity & specificity & positive/negative predictive values against standard hospital lab procedures (gram stain, cell count and culture), non-harmful bacteria will be used in a university lab. The trial will subsequently use (1) control normal synovial fluid +/- live stains (LIVE BacLight) and (2) known infected synovial fluid to test and benchmark against gold-standard hospital microbiology laboratory protocol. Power calculations (α 0.05, β 0.2) estimate a sample size of 125 (paired controls – comparing lab-based gold-standard to our method) to estimate a sensitivity of 0.97 with a 95% CI of 0.94-1.00, based off Hajian-Tilaki (2014). We have sought Human Research Ethics Committee approval. 

The basis of our methodologies are simple as exemplified below. 

Figure 1 - not reinventing the wheel. Our method uses microscopy to identify bacteria and as seen in figure, bring this to the next level by using fluorescence, much like fluorescein when examining the cornea for uptake/damage.  

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