# Meropenem-Responsive Pandoraea apista Pneumonia Despite High-Level In Vitro Resistance: A Rare Case in an Older Non-cystic Fibrosis Patient

## TL;DR

A rare case of Pandoraea apista pneumonia in a non-cystic fibrosis patient showed improvement with meropenem despite in vitro resistance.

## Contribution

Demonstrates successful treatment of P. apista with meropenem despite high-level resistance through optimized dosing.

## Key findings

- P. apista was isolated from a non-CF patient with hospital-acquired pneumonia.
- Meropenem improved the patient's condition despite in vitro resistance.
- Optimized dosing achieved favorable drug exposure above the minimum inhibitory concentration.

## Abstract

Pandoraea apista is a rare, non-fermenting, gram-negative bacillus mainly seen in cystic fibrosis (CF) patients. It is now increasingly being isolated in non-CF patients, mostly those who are critically ill or have multiple comorbidities. We describe a patient with no history of CF who was admitted with hospital-acquired pneumonia. The sputum culture grew P. apista, which was resistant to many antibiotics, including meropenem. Despite the in vitro resistance, the patient improved when kept on meropenem after the culture result was available. This was mostly due to optimized dosing and favorable exposure above the minimum inhibitory concentration. Our case highlights these diagnostic challenges and variable resistance patterns. It also emphasizes the important role of personalized therapy tailored to each patient and their condition.