# Historical Overview of the Evolution of Multidrug-Resistant Gram-Negative Infections in Tunisia from 1999 to 2019

## TL;DR

This study tracks the rise of antibiotic resistance in Gram-negative bacteria in Tunisia from 1999 to 2019, highlighting growing threats from multidrug-resistant strains.

## Contribution

The paper provides a 20-year longitudinal analysis of antimicrobial resistance trends in four key Gram-negative pathogens in Tunisia.

## Key findings

- E. coli resistance to third-generation cephalosporins increased from 5.4% in 2004 to 16.5% in 2019.
- A. baumannii resistance to imipenem rose from 34.5% in 2008 to 84.2% in 2019, showing alarming multidrug resistance.
- K. pneumoniae resistance to imipenem increased from 1% in 2005 to 18.6% in 2019, though amikacin remained effective.

## Abstract

Background/Objectives: As antimicrobial resistance patterns of Gram-negative bacteria change over time, this study aimed to analyze the antimicrobial susceptibility trends of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii isolates in Tunisia. Methods: From 1999 to 2019, non-duplicate isolates of Gram-negative bacteria were collected from 11 Tunisian hospitals as part of an antimicrobial resistance surveillance program. Antimicrobial susceptibility testing was performed using the disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing guidelines. Results: Out of 213,434 isolates collected during the study period, 58.8% were E. coli, 22% were K. pneumoniae, 14.4% were A. baumannii, and 4.8% were P. aeruginosa, with 67% of the isolates sourced from urine samples. E. coli showed a significant increase in resistance to third-generation cephalosporins (3GC), from 5.4% in 2004 to 16.5% in 2019, but K. pneumoniae displayed a rising trend of resistance to imipenem, from 1% in 2005 to 18.6% in 2019; meanwhile, amikacin remained effective against K. pneumoniae isolates. P. aeruginosa did not exhibit a significant change in resistance to imipenem. A. baumannii had a high resistance rate to imipenem that increased from 34.5% in 2008 to 84.2% in 2019 and had low susceptibility rates to all other antibiotics tested. Conclusions: This study reveals high carbapenem resistance among K. pneumoniae and A. baumannii in Tunisia. A. baumannii shows alarming multidrug resistance that requires urgent control measures.