# P-178. Cost Savings of Carba-R Gene Xpert® Testing for Targeted Treatment Compared to Empiric Ceftazidime-Avibactam/Aztreonam Combination for Carbapenem-Resistant Klebsiella pneumoniae in a Resource-Limited Setting with a High Prevalence of blaNDM

## TL;DR

This study shows that using a molecular test to guide antibiotic treatment for a specific type of antibiotic-resistant bacteria in the Philippines saves money compared to a standard but more expensive treatment.

## Contribution

The study demonstrates cost savings of targeted treatment using Carba-R Gene Xpert® testing over empiric combination therapy for CR-Kp in a resource-limited setting.

## Key findings

- Targeted therapy based on molecular testing saved $11,556.87 per 100 CR-Kp patients compared to empiric combination therapy.
- Most CR-Kp isolates in the Philippines carry the blaNDM gene, which requires combination therapy, while others can be treated with monotherapy.
- Molecular testing costs are offset by reduced antibiotic expenses in patients without the blaNDM gene.

## Abstract

The Philippines has seen a significant increase in carbapenem resistance (CR) in Klebsiella pneumoniae in recent years, with a current nationwide CR rate of nearly 17%. A recent study by our group revealed that 92% of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) isolates harbor at least one carbapenemase gene, with the following distribution: blaNDM (68.8%), blaOXA-48-like (38.5%), and blaKPC (28.6%). Standard treatment of CR-Kp with blaNDM is with combination ceftazidime/avibactam and aztreonam, which is prohibitively expensive in our setting. Most Filipinos have no private insurance and public health insurance pays a small percentage of actual health costs, with the rest being out of pocket. Treatment of blaKPC and blaOXA-48-like can be done with ceftazidime/avibactam monotherapy. We determined whether the significant cost of molecular testing can be offset by targeted monotherapy as opposed to empiric combination therapy for all CR-Kp infections.

We set antibiotic costs based on retail prices of each antibiotic in our pharmacy and set molecular testing costs based on commercial rates. We compared an empiric treatment scenario with targeted testing based on the previous carbapenemase gene distributions. We calculated cost savings for every 100 CR-Kp patients who underwent molecular testing compared to empiric therapy using a standard 7-day course of antibiotics.

ScenarioNumber of patients to be treated (n = 100)Cost of 7-day course (in USD*)#Cost of Carba-R test (in USD)Cost (in USD)Scenario 1: Empiric CZA/ATM for all patients100CZA/ATM396,312.47No testing396,312.47Scenario 2: Directed therapy63 NDMCZA/ATM249,676.859,027.40258,704.2637 non-NDMCZA only120,749.535,301.81126,051.34Total cost of directed therapy384,755.60Cost savings with directed therapy per 100 patients tested11,556.87*1 USD = 55.83 PhP as of April 30, 2025
#CZA cost/individual = 3,263.50 USD, ATM cost/individual = 699.62 USD
&Carba-R cost/individual = 143.29 USD

*1 USD = 55.83 PhP as of April 30, 2025

#CZA cost/individual = 3,263.50 USD, ATM cost/individual = 699.62 USD

&Carba-R cost/individual = 143.29 USD

The cost of testing with Carba-R Gene Xpert® among CR-Kp -infected Filipino inpatients is more than offset by the added costs of empiric treatment, in addition to indirect benefits of improved antimicrobial stewardship and decreased downstream rates of resistance.

All Authors: No reported disclosures