A study on different approaches that can be used to combat resistance caused by MDR Acinetobacter baumannii pathogens

Abstract

Antimicrobial resistance is an increasing threat; both mortality and morbidity from infection are greater when caused by antimicrobial-resistant bacteria. Nowadays, resistance to antibiotics has been reaching a critical level, invalidating major antimicrobial drugs that are currently used in the treatment of infections. The growing resistance of pathogenic bacterial strains to traditional antibacterial treatments has encouraged alternate strategies to combat infections. Actually, identification of new antimicrobial agents, particularly those that affect novel targets, is needed to provide effective treatment options. As part of the continued global effort to discover novel antimicrobials, many laboratories are now dedicated to the invention novel antimicrobial compound. The combination therapy has been studied as a possible solution of the resistant A. baumannii challenge with few studies reporting promising results. In this study, antibiotic combinations were evaluated by checkerboard micro-dilution method. The MICs of the antibiotics in the combinations were significantly reduced as compared to the MICs of each drug alone, and thereby gave synergism. In this study, the CT-MEM combination demonstrated a synergistic effect in 77.7% of the isolates. The TGC-MEM combination showed a synergistic and additive effects for 44.4% and 55.6% of the tested isolates, respectively. The CT-TGC combination showed antagonist effect for 100% of the isolates. CNPs were prepared and characterized by DLS (to measure hydrodynamic diameter within the nanometer range) and confirmed by imaging the formed CNPs through TEM. The size of CNPs at selected concentration was 441.7 nm and Zeta potential positive 37.7mV which mean that the formed nanoparticles were stable and of smaller particle size with positive charge on the surface of the CNPs indicating high sorption capacity and good antimicrobial properties. The HR-TEM images have shown the morphological properties and surface appearance of nanoparticles. Morphologically, the CNPs prepared were found to be spherical in shape and of smooth surface indicating good properties of the synthesized CNPs.