Antimicrobial Resistance and Infection Control for Gram-positive Bacteria

Abstract

Antimicrobial resistance (AMR) is a serious problem worldwide. We searched for the AMR determinants of various bacteria isolated from clinical settings and studied their resistance mechanisms and molecular epidemiology. This review focuses on the AMR of Staphylococcus aureus, a major gram-positive pathogen, which has the ability to acquire resistance to antimicrobials. The resistance factors of S. aureus are frequently found on mobile elements, including plasmids and transposons. We determined the complete DNA sequence of the tetracycline-resistance plasmid and found that the inducible expression of tetK in S. aureus was regulated by a post-transcriptional attenuation mechanism. Furthermore, outbreaks of methicillin-resistant S. aureus (MRSA) in hospitals and communities have led us to study infection controls, including the antiseptic susceptibility evaluation and molecular epidemiology of MRSA. Various antiseptic resistance determinants, such as qacA/B and smr, were identiˆed on plasmids and characterized. We demonstrated that the plasmid-mediated eOEux pump QacB variant QacIII confers ‰uoroquinolone eOEux ability to S. aureus. Studies on MRSA epidemiology had shown that community-acquired MRSA (CA-MRSA) was disseminated into hospitals and that an increased use of alcohol-based rubs could reduce the incidence of MRSA infections in such institutions. Additionally, the study of CA-MRSA collected from communities and hospitals showed an increase in Panton-Valentine leucocidin (PVL)-positive CA-MRSA, causing severe skin and soft tissue infections. Moreover, various PVL-positive CA-MRSA clones have disseminated in Japan, whereas the USA300 LV/J clone evolved in that country. Our study provides important information regarding MRSA infection control.

Electroacoustic Biosensor Systems for Evaluating Antibiotic Action on Microbial Cells

“…Methicillin-resistant strains of S. aureus are resistant to all β-lactams and cephalosporins and are responsible for 13–74% of all S. aureus infections [ 11 ]. Cases of resistance to vancomycin, daptomycin, linezolid, and teicoplanin have been described in [ 12 , 13 ].…”

Heparinoid enhances the efficacy of a bactericidal agent by preventing <i>Cutibacterium acnes</i> biofilm formation via quorum sensing inhibition

“…Cutibacterium acnes is an opportunistic pathogen associated with acne vulgaris, especially inflammatory acne. C. acnes proliferation within comedones is among the main causes of inflammation (Noguchi 2021) . On the skin, C. acnes would proliferate until reaching a high population density then it would form a biofilm (Alexeyev et al 2012;Bayston et al 2007;Ramage et al 2003;Sardana et al 2015) through extracellular matrix excretion, thereby increasing its resistance against bactericidal agents (Cañellas-Santos et al 2023) .…”