Antimicrobial resistance remains, more than ever, a key issue for medical microbiology. The development of antibiotic resistance by bacteria is an evolutionary inevitability, a convincing demonstration of their ability to adapt to adverse environmental conditions. Some Gram-positive organisms are extremely adaptable and rapidly develop resistance, whereas others have not developed good strategies to overcome antibiotics. Staphylococci and enterococci, in particular are associated with clinically relevant resistance. The epithet of superbugs, if one can define these as bacterial pathogens resistant to almost all clinically available agents, can be truly applied to resistant strains of Gram-positive species, especially to methicillin-resistant Staphylococcus aureus (MRSA) and to glycopeptide- or vancomycinresistant enterococci (GRE or VRE).
Table of Contents
Chapter One Gram-Positive Organisms as Human Pathogens
Chapter Two Antibiotics against Gram positive cocci: Mechanism of action
Chapter Three Mechanisms of Antibiotic Resistance
Chapter Four Antimicrobial Susceptibility Testing
Research Objectives and Topics
The primary objective of this work is to provide a comprehensive review of the modes of action and mechanisms of antibiotic resistance in Gram-positive cocci, as well as the methodologies for their laboratory identification. The research explores the evolutionary adaptation of bacterial pathogens and the clinical implications of antimicrobial resistance in modern medical practice.
- Clinical significance of Gram-positive organisms as human pathogens.
- Mechanisms of action for common antibiotic classes and their respective resistance pathways.
- Genetic basis of antibiotic resistance, including mobile genetic elements like plasmids, transposons, and integrons.
- Standard and advanced phenotypic and genotypic methods for antimicrobial susceptibility testing.
- Clinical challenges posed by multidrug-resistant pathogens such as MRSA and VRE.
Excerpt from the Book
I)1. Staphylococci
Staphylococci are responsible for a plethora of medical problems, including skin and soft-tissue infections (SSTIs), surgical site infections (SSIs), endocarditis and bacteraemia. An increasing number of infections are related to medical developments, including the use of joint prostheses, immunosuppressants and catheters (Casey et al., 2007).
Staphylococcus aureus was first documented as a human pathogen in the 19th century. Today, it is the most common single pathogen in human medicine causing serious, invasive infections such as soft tissue infections, endocarditis, osteomyelitis, bacteremia, septic arthritis, and nosocomial pneumonia (Drew, 2007, Metzger et al., 2009).
S.aureus is a major cause of many serious hospital- and community-acquired infections. It is also the most common cause of hospital-acquired bacteraemia and is associated with significant morbidity and mortality rates of up to 64%, varying with the infection site and the susceptibility of the particular strain. This pathogenicity reflects its ability to produce a variety of toxins, to attach firmly to prosthetic material by production of a glycocalyx and to an extraordinary ability to develop antimicrobial resistance (Casey et al., 2007).
Summary of Chapters
Chapter One Gram-Positive Organisms as Human Pathogens: Discusses the role of common Gram-positive bacteria in human disease, highlighting the clinical impact of staphylococci, enterococci, and streptococci.
Chapter Two Antibiotics against Gram positive cocci: Mechanism of action: Reviews the mechanisms of action and bacterial resistance strategies for various antibiotic classes, including beta-lactams, glycopeptides, and newer agents.
Chapter Three Mechanisms of Antibiotic Resistance: Explores the genetic foundations of resistance, detailing the roles of mutation, gene exchange, and mobile genetic elements in the development of multidrug-resistant bacterial strains.
Chapter Four Antimicrobial Susceptibility Testing: Details the clinical laboratory procedures for identifying phenotypic and genotypic antibiotic susceptibility to guide appropriate therapeutic interventions.
Keywords
Antibiotic resistance, Gram-positive cocci, Staphylococcus aureus, MRSA, VRE, antimicrobial susceptibility testing, beta-lactams, glycopeptides, horizontal gene transfer, mobile genetic elements, integrons, MIC, phenotypic assays, genotypic assays, bacteremia.
Frequently Asked Questions
What is the core focus of this publication?
The book focuses on the interplay between Gram-positive bacterial pathogens, the antibiotics used to treat them, the underlying mechanisms of bacterial resistance, and the diagnostic methods used to detect susceptibility.
What are the primary themes discussed?
The primary themes include bacterial pathogenesis, antibiotic mechanisms of action, the genetics of antibiotic resistance, and modern laboratory diagnostics for clinical decision-making.
What is the main research question or objective?
The objective is to synthesize current clinical and microbiological knowledge regarding how Gram-positive cocci develop resistance to standard treatments and how laboratories can effectively identify these resistance patterns to improve patient outcomes.
Which scientific methods are primarily addressed?
The work addresses both phenotypic assays like disk diffusion and MIC testing, as well as genotypic methods including PCR, sequencing, and microarray analysis.
What topics are covered in the main section of the book?
The main sections cover individual classes of antibiotics, their specific molecular targets, the evolution of resistance via plasmids and transposons, and the clinical limitations of current therapeutic approaches.
Which keywords characterize this work?
Key terms include antimicrobial resistance, MRSA, VRE, mobile genetic elements, and susceptibility testing techniques.
How does the book address the emergence of multidrug-resistant bacteria?
It explains the emergence of "superbugs" through mechanisms like horizontal gene transfer, the acquisition of mobile genetic elements, and selective evolutionary pressure in hospital environments.
What specific role do integrons play in antibiotic resistance?
Integrons act as gene capture systems that allow bacteria to accumulate multiple resistance cassettes, facilitating the development of high-level multidrug resistance.
Why is the "D-zone test" important in clinical practice?
The D-zone test is essential for detecting inducible clindamycin resistance in erythromycin-resistant isolates, preventing treatment failure in clinical staphylococcal infections.
- Quote paper
- maysaa el sayed zaki (Author), 2013, Antibiotics toward Gram Positive Cocci: Mode of Action, Resistance and Laboratory Diagnosis, Munich, GRIN Verlag, https://www.grin.com/document/231361
