INTRODUCTION

Antibiotics are vital drugs in the treatment of bacterial infections, but their misuse and excessive use lead to bacteria developing resistance to these drugs. Unnecessary use of broad-spectrum antibiotics or incorrect doses leads to the emergence of multidrug-resistant Gram-negative and Gram-positive bacteria (1). The high morbidity and mortality rates seen in hospital outbreaks in recent years have led to the search for new treatment options. Studies have directed the development of new antibiotics, and at the same time, compounds with different pharmacological effects have been shown to have significant antibacterial activity. Some in vitro studies have shown that beta-blockers can affect bacterial cell membranes (2). The aim of our study is to investigate the in vitro efficacy of combinations of antihypertensive drugs beta-blockers (esmolol and normolol) and vancomycin and meropenem antibiotics, which are frequently used in hospital infections, on Gram-positive and Gram-negative bacteria.

MATERIAL AND METHODS

The study included standard bacterial strains from the Microbiology Laboratory of Sanko University Faculty of Medicine and clinical isolates of multidrug-resistant Enterobacter cloacae, Klebsiella pneumoniae, Acinetobacter baumannii, Proteus mirabilis and vancomycin-resistant Enterococcus faecalis (VRE), methicillin-resistant Staphylococcus aureus (MRSA). Identification and antibiograms of the isolates were studied in accordance with EUCAST standards using the BD Phoenix100 (Becton Dickinson, USA) automated system and confirmed by the disk diffusion method (3). The relationship between the efficacy of vancomycin and meropenem antibiotics and beta-blockers was tested using the disk diffusion method.

RESULTS

When the antibiotic susceptibility results of vancomycin and beta-blocker combinations (esmolol and normolol) were evaluated in Gram-positive bacteria, it was seen that no change was detected in vancomycin efficacy (Table-1). When the antibiotic susceptibility results of meropenem and beta-blocker combinations (esmolol and normolol) were evaluated in Gram-negative bacteria, it was seen that there was no change in normolol combination. In the combination with esmolol, an increase in meropenem inhibition zone diameters was observed in Enterobacter cloacae, Klebsiella pneumoniae, Proteus mirabilis isolates.

DISCUSSION

Our study is a preliminary study in which we evaluated the in vitro synergistic effect of vancomycin and meropenem antibiotics, which are frequently used in the treatment of hospital infections, with beta-blockers in the antihypertensive group. It was thought that esmolol may have a synergistic effect in combination with meropenem in Enterobacter cloacae, Klebsiella pneumoniae, Proteus mirabilis isolates. Our findings suggest that this could be a potentially effective combination for use in clinical practice. Further pharmacokinetic/pharmacodynamic studies are required to guide the use of these new promising combinations.