JOURNAL OF BACTERIOLOGY AND VIROLOGY ISSN:1598-2467(Print) 2093-0429(Online)

Multidrug-resistant bacteria, including extended-spectrum β-lactamase-producing Enterobacterales and methicillin-resistant Staphylococcus aureus, pose a major therapeutic challenge in Niger. Ceftaroline, a fifth-generation cephalosporin, offers potential activity against these pathogens. This study aimed to evaluate the in vitro activity of ceftaroline against multidrug-resistant bacteria isolated in Niger and to identify factors associated with resistance. A prospective cross-sectional study was conducted from January to August 2025. A total of 212 non-duplicate multidrug-resistant isolates (160 extended-spectrum β-lactamase-producing Enterobacterales, 52 methicillin-resistant Staphylococcus aureus) were tested using the disk diffusion method. Logistic regression was used to identify factors independently associated with ceftaroline resistance. The overall resistance rate to ceftaroline was 69.3% (147/212). extended-spectrum β-lactamase-producing Enterobacterales isolates exhibited a very high resistance rate (80.6%), whereas methicillin-resistant Staphylococcus aureus (MRSA) isolates showed lower resistance (34.6%). In multivariate analysis, extended-spectrum β-lactamase-producing Enterobacterales phenotype (Odds Ratio=5.03; 95% Confidence Interval=2.13-11.83), concurrent resistance to aminoglycosides (Odds Ratio=2.55; 95% Confidence Interval=1.21-5.33), fosfomycin (Odds Ratio=3.42; 95% Confidence Interval=1.01-11.50), and cotrimoxazole (Odds Ratio=3.97; 95% Confidence Interval=1.20-13.02) were significant factors independently associated with ceftaroline resistance. This first study conducted in Niger reveals an alarming rate of in vitro resistance to ceftaroline among multidrug-resistant bacteria, primarily extended-spectrum beta-lactamase-producing Enterobacterales. Ceftaroline should not be used empirically for suspected infections with these pathogens in this context. Its use against methicillin-resistant Staphylococcus aureus must be guided by susceptibility testing. These data call for revisions to therapeutic protocols and reinforcement of antimicrobial stewardship strategies.