Comparative Outcomes of Meropenem and Imipenem in Multidrug-Resistant Pulmonary Infections: A Prospective Cohort Study

Summary

The present protocol describes that Meropenem and Imipenem show comparable pathogen clearance; however, Meropenem demonstrates faster symptom relief, improved lung function, reduced inflammatory markers, and fewer adverse effects, indicating its potential as a safer and more effective first-line therapy for MDR pulmonary infections.

Abstract

Pulmonary infections due to multidrug-resistant (MDR) organisms (MDRO) pose a significant global public health challenge due to their high mortality rates and complex management. Carbapenem antibiotics, including Meropenem and Imipenem, are cornerstone therapies for MDR Gram-negative bacterial infections, with their efficacy and safety critically influencing patient outcomes. In this prospective cohort study, we compared the day-7 pathogen clearance rates of Meropenem and Imipenem in MDR bacterial pulmonary infections and also evaluated prespecified secondary clinical and safety outcomes. For the primary endpoint, no statistically significant difference was observed between the two groups in day-7 pathogen clearance (P>0.05). However, supportive secondary analyses showed that the meropenem group had shorter observed times to resolution of cough, sputum production, lung rales, and fever (P<0.05). In addition, meropenem-treated patients showed greater improvement in selected lung function parameters, a more pronounced reduction in PaCO₂ (P<0.05), lower post-treatment PCT and hs-CRP levels (P<0.05), and fewer reported adverse events (P<0.05). These observational findings suggest that Meropenem may offer clinical advantages in MDRO-induced pulmonary infections, although the results should be interpreted in the context of the non-randomized study design.

Introduction

Multidrug-resistant (MDR) organism (MDRO)-induced pulmonary infections pose a significant global public health challenge¹. In recent years, the increasing prevalence of MDROs (e.g., carbapenem-resistant Enterobacteriaceae, Acinetobacter baumannii) has been driven by factors such as antibiotic overuse, nosocomial transmission, and bacterial evolution². The World Health Organization reports that infections with MDR strains are associated with higher mortality rates compared to susceptible strains, particularly in intensive care units (ICUs), where treatment complexity and healthcare costs present substantial clini....

Protocol

This study was approved by the Ethics Committee of Nantong Third People’s Hospital (Approval No. 2025NG023). Written informed consent was obtained from all participants prior to enrollment. All procedures were conducted in accordance with the principles of the Declaration of Helsinki and institutional ethical guidelines. The reagents and the equipment used are listed in the Table of Materials.

1. Research subjects
The potential research participants were MDRO-induced pulmonary infection patients hospitalized between March 2024 and January 2025. The required sample size was calculated using G*Pow....

Results

Clinical data comparison
The baseline characteristics, including demographic variables, major clinical features, microbiological profile, and baseline carbapenem susceptibility data, were compared between the groups. The analysis revealed no statistically significant differences (P>0.05), indicating comparable baseline profiles (Table 1).

Primary endpoint: Similar Day-7 pathogen clearance between groups
For the primary endp.......

Discussion

MDRO-induced pulmonary infections pose a significant challenge in critical care medicine worldwide due to their high mortality rates and complex treatment requirements¹². This study is the first to prospectively compare the pathogen clearance efficacy of Meropenem and Imipenem in patients with MDRO lung infections. The findings revealed no statistically significant difference in pathogen eradication between the two groups. However, the meropenem group demonstrated superior outcomes in clinical sym.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Antimicrobial Susceptibility Test Card	bioMérieux, France	Compatible with VITEK 2 Compact	Compatible with automated antimicrobial susceptibility testers, determining the MIC values of strains to drugs such as meropenem and imipenem
Arterial Blood Gas Analyzer	Radiometer, Denmark	ABL800	Used to detect partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2) in patient arterial blood, evaluating pulmonary gas exchange function
Automated Antimicrobial Susceptibility Tester	bioMérieux, France	VITEK 2 Compact	Used for antimicrobial susceptibility testing of bacteria isolated from baseline respiratory specimens; MIC results interpreted according to CLSI standards
Automated Biochemical Analyzer	Hitachi, Japan	Hitachi 7600	Used to detect liver and kidney function indicators (ALT, AST, BUN, Scr) in patient serum, providing data for clinical safety assessment
Blood Agar Medium	Hangzhou Microbial Reagent Co., Ltd., China	CM115	Used for bacterial isolation and pure culture of respiratory specimens, providing strains for MDRO identification and antimicrobial susceptibility testing
Ciprofloxacin Injection	Bayer Healthcare Co., Ltd., China	0.2g Specification	Adjuvant therapeutic medication, used for combined antimicrobial treatment of patients with Pseudomonas aeruginosa co-infection
Clot-Activator Blood Collection Tube	Shandong Weigao Group Medical Polymer Products Co., Ltd., China	3.5mL Specification	Used for collecting fasting venous blood, separating serum for liver and kidney function testing and inflammatory marker detection
ELISA Detection Kit (hs-CRP)	R&D Systems, USA	DY2915	Quantitatively detects high-sensitivity C-reactive protein concentration in patient serum, evaluating the degree of systemic inflammatory response
ELISA Detection Kit (IL-17A)	R&D Systems, USA	DY317	Quantitatively detects interleukin-17A concentration in patient serum, evaluating the level of cytokines related to inflammatory response
ELISA Detection Kit (IL-6)	R&D Systems, USA	DY206	Quantitatively detects interleukin-6 concentration in patient serum, reflecting the degree of cytokine-mediated inflammatory activation
ELISA Detection Kit (PCT)	R&D Systems, USA	DY1758	Quantitatively detects procalcitonin concentration in patient serum, reflecting the burden of bacterial infection
ELISA Detection Kit (SAA)	R&D Systems, USA	DY1827	Quantitatively detects serum amyloid A concentration in patient serum, reflecting systemic inflammatory response of the body
G*Power software	Heinrich Heine University Düsseldorf, Germany	https://www.psychologie.hhu.de/arbeitsgruppen/allgemeine-psychologie-und-arbeitspsychologie/gpower	G*Power is a  statistical software used for a priori and post hoc power analysis and sample size estimation for common parametric and nonparametric tests.
High-Speed Refrigerated Centrifuge	Xiangyi Laboratory Instrument Development Co., Ltd., China	TDZ5-WS	Used to separate fasting venous blood samples, achieving separation of serum and blood cells, and providing samples for subsequent biochemical and ELISA testing
Imipenem Injection	Merck & Co., Inc., USA	0.5g Specification	Control group medication; administered intravenously at a dose of 0.5g every 8 hours, with an initial loading dose of 1g and an infusion time ≥30 minutes
Lithium Heparin Anticoagulant Blood Collection Tube	Shandong Weigao Group Medical Polymer Products Co., Ltd., China	3mL Specification	Used for collecting arterial/venous blood, for arterial blood gas analysis testing, preventing blood coagulation
Liver and Kidney Function Test Kit (ALT/AST)	Sinobiological Beikong Biotechnology Co., Ltd., China	Compatible with Hitachi 7600/20240205	Uses colorimetry to detect alanine transaminase and aspartate transaminase in serum, evaluating liver function status
Liver and Kidney Function Test Kit (BUN/Scr)	Sinobiological Beikong Biotechnology Co., Ltd., China	Compatible with Hitachi 7600	Uses rate method to detect blood urea nitrogen and serum creatinine in serum, evaluating renal function status
MacConkey Agar Medium	Hangzhou Microbial Reagent Co., Ltd., China	CM106	Used for isolation and preliminary identification of Gram-negative bacteria, screening pathogenic bacteria in respiratory specimens
Meropenem Injection	Hengrui Pharmaceutical Co., Ltd., China	0.5g/1.0g Specification	Study group medication; administered intravenously at a dose of 0.5g/1.0g every 8 hours, with an initial loading dose of 1g and an infusion time ≥30 minutes
Microplate Reader	Thermo Fisher Scientific, USA	Multiskan FC	Used with ELISA kits to detect absorbance values of inflammatory markers in serum and quantitatively analyze concentrations of indicators such as SAA and IL-6
Pipette	Eppendorf, Germany	Research plus	Used for precise pipetting in ELISA experiments and sample processing, ensuring the accuracy of experimental operations
Pulmonary Function Tester (Spirometer)	Jaeger, Germany	MasterScreen PFT	Used to detect pulmonary function indicators such as forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) in patients, following ATS/ERS standardized operating procedures
SPSS Statistical Software	IBM Corporation, USA	24	Used for statistical analysis of all data in the study, including chi-square test, t-test, nonparametric test, etc.
Vancomycin Injection	Eli Lilly and Company, USA	0.5 g Specification	Adjuvant therapeutic medication, used for combined antimicrobial treatment of patients with methicillin-resistant Staphylococcus aureus (MRSA) co-infection