(66) Implementation of Standardized Pseudomonas aeruginosa Eradication Protocol

Background: Chronic Pseudomonas aeruginosa (PSA) infection is associated with accelerated lung function decline in patients with cystic fibrosis (CF), resulting in the CF Foundation recommending inhaled tobramycin for 28 days for eradication of PSA to prevent colonization.[1] There is no recommendation for how to proceed if the initial eradication attempt fails, resulting in variability from provider to provider at our center, which was confusing for both patients and staff. Blanchard et al. published a stepwise protocol with high rates of pseudomonas eradication. [2] To standardize our approach, we adopted this protocol in the Michigan State University CF Center and monitored both patient adherence to the protocol and eradication outcomes.

Methods: A PSA eradication protocol (Figure 1) was developed in collaboration with CF providers and a pediatric infectious disease physician at our institution. We started with inhaled tobramycin for 28 days, if this failed a second course of inhaled tobramycin was attempted. If both failed, a two-week course of intravenous antipseudomonal antibiotics was recommended followed by an additional four weeks of inhaled tobramycin. If the patient developed an exacerbation the treatment was shifted to the intravenous antibiotic regimen. We closely monitored respiratory cultures after treatment for eradication which we defined as three negative cultures with at least one negative culture more than six months after the treatment.

Results: The protocol was implemented in April of 2017. As of the time of submission 14 patients met criteria for completion of the protocol on 18 occasions with four patients having grown PSA after prior eradication. Of the 18 protocol completions 12 patients completed the protocol as written. Two patients declined admission for IV therapy after inhaled tobramycin failed and both are still colonized with PSA. One patient received two months of inhaled tobramycin on step two instead of one resulting in eradication. Our eradication rate was 83% (15/18) in all patients and 100% (12/12) in patients who adhered to the protocol. 80% (12/15) of eradications were following step one , 13.3% following step two (2/15), and 6.7% following step three (1/15). Two of those four patients who met criteria for eradication, but subsequently grew PSA again within three years of eradication, were successfully eradicated a second time.

Conclusions: We successfully implemented a multistep protocol for PSA eradication at our center leading to a consistent approach. Our eradication success was consistent with the Blanchard paper, but in a real-world setting. Primary barriers to protocol adherence were inadequate follow-up cultures and refusal of intravenous therapies for eradication. Prospective studies are needed to determine the most effective eradication strategy.

Acknowledgements:

References: [1] Mogayzel PJ Jr, Naureckas ET, Robinson KA, Brady C, Guill M, Lahiri T, Lubsch L, et al.; Cystic Fibrosis Foundation Pulmonary Clinical Practice Guidelines Committee. Cystic Fibrosis Foundation pulmonary guideline. pharmacologic approaches to prevention and eradication of initial Pseudomonas aeruginosa infection. Ann Am Thorac Soc. 2014 Dec;11(10):1640-50. doi: 10.1513/AnnalsATS.201404-166OC.

[2] Blanchard AC, Horton E, Stanojevic S, Taylor L, Waters V, Ratjen F. Effectiveness of a stepwise Pseudomonas aeruginosa eradication protocol in children with cystic fibrosis. J Cyst Fibros. 2017 May;16(3):395-400. doi: 10.1016/j.jcf.2017.01.007.