EPIDEMIOLOGY OF ANTIMICROBIAL RESISTANCE
2. EPIDEMIOLOGY OF ANTIMICROBIAL RESISTANCE
The epidemiology of AR is complex and influenced by many factors. Understanding the problem requires that the rates of changes in the suscepti- bility to specific antibiotics of organisms isolated from both man and animals
be available. This enables a scientific risk assessment to be made and baselines for intervention to be established (Vose et al., 2001). In a bacterial population,
AR and its Containment in DCs 619 the three conditions responsible for the rapid spread of AR are the presence of
resistance determinants, vertical or horizontal spread of these resistance determinants, and selection pressure (Edelstein, 2002; Franklin et al., 2002; O’Brien, 2002).
The genetic basis and the phenotypic expression of resistance is extremely complex. This is because there are different classes of antimicrobials each with
a different molecular target and a single bacterial species may exhibit more than one resistance mechanism against a single class of antimicrobes (Smith and Lewin, 1993). Some bacterial species develop (or acquire) resistance more readily than others when exposed to apparently similar selective pressures (Ellner et al., 1987). Whether particular organisms become resistant to a par- ticular antimicrobial agent may depend on many factors including the basic physiology of the bacteria, the characteristics of genetic mutations that occur, the prevalence of resistance genes that might be acquired, or the quantity and quality of exposure to the antimicrobial agent (Parry, 1989). For example Escherichia coli and enterococci (Enterococcus faecium and Enterococcus faecalis) are used internationally as Gram-negative and positive indicator bacteria, respectively, because of their ability to harbour several resistance determinants (Aarestrup, 1999; Caprioli et al., 2000; Catry et al., 2003).
Rapid spread of genes resistant to antimicrobial agents can occur in a bacterial population and from one ecosystem to another. Particular antibiotic resistance genes first described in human specific bacteria have been found in animal specific species of microorganisms and vice versa, suggesting those bacterial populations can share and exchange these genes (Aarestrup, 2000). The development of resistance in one bacterial population can, and does, spread to other populations over time.
The selection pressure determines the rate and extent of the emergence of AR. The prevalence and persistence of AR is the result of the complex interac- tion between antimicrobial drugs, microorganisms, the host, and the environ- ment (O’Brien, 2002). It alters the populations through the elimination of susceptible organisms and the survival of resistant ones. The use of antimicro- bials is the main cause of selection pressure(Aarestrup, 2000; Drlica, 2003; Sexton, 2000). Pathogenic organisms are clearly the target population of antimicrobial drugs, on which, by consequence a selection pressure can be exerted. Antimicrobial drugs also exert selection pressure on commensal bac- teria (Blake et al., 2003). Commensal bacteria are present on the skin, in the upper respiratory tract, and especially in the digestive tract. The levels of AR in faecal commensal bacteria can reflect the selection pressure exerted by the use of antimicrobial agents in a certain environment (van den, 2001).
Monitoring AR gives very useful data. However, in pathogenic bacteria, it may be less accurate because the resistance patterns of pathogenic strains isolated from autopsy or following therapy failure can be altered by the
620 Denis K. Byarugaba preceding antimicrobial treatment (Caprioli et al., 2000). Susceptibility
patterns of indicator bacteria derived from healthy individuals are suggested as
a good predictor of the resistance situation in the bacterial population as a whole (van den, 2001). The difference in the epidemiology of AR between the developed nations and DCs is the environmental factors especially to do with hygiene and disease control and management.
Parts
» Antibiotic Policies: Theory and Practice
» THEORIES OF FACILITATING CHANGE
» OTHER APPROACHES TO GUIDELINE DEVELOPMENT
» QUALITY ASSURANCE AND DEVELOPMENT OF STANDARDS
» DEVELOPMENT OF CLINICAL STANDARDS IN SCOTLAND
» WHICH QI INTERVENTIONS HAVE BEEN STUDIED IN CAP?
» LINKING PROCESS OF CARE TO OUTCOMES IN QI
» WHAT IS THE EVIDENCE THAT QI INITIATIVES IMPROVE PROCESS OF CARE IN CAP?
» WHAT IS THE EVIDENCE THAT QI INITIATIVES IMPROVE OUTCOMES IN CAP?
» Designing and implementing a CAP intervention
» LEVEL OF AGGREGATION OF ANTIMICROBIALS
» ANTIMICROBIAL USAGE MEASURES
» Relationships based on patient-specific data
» Relationships based on aggregate usage
» ANTIBIOTIC CONSUMPTION; ALTERNATIVE UNITS OF MEASUREMENT
» ANTIBIOTIC CONSUMPTION CALCULATOR
» BENCHMARKING FOR REDUCING VANCOMYCIN USE AND VANCOMYCIN- RESISTANT ENTEROCOCCI IN US ICU S
» THE HARVARD EMERGENCY DEPARTMENT QUALITY STUDY
» ANALYSIS BY INDIVIDUAL ANTIMICROBIAL AGENT
» BENCHMARKING WITH OTHER ANTIMICROBIAL UTILISATION DATA
» STATE OF THE ART OF ANTIBIOTIC PROPHYLAXIS IN SURGERY
» AUDITING AND IMPROVING THE QUALITY OF ANTIBIOTIC PROPHYLAXIS IN SURGERY
» TYPES OF STUDIES TO OBTAIN QUALITY DATA ON A PATIENT LEVEL
» MULTIDISCIPLINARY ANTIMICROBIAL MANAGEMENT TEAMS
» THE ROLE OF THE PHARMACIST IN INFECTION MANAGEMENT
» TRAINING AND SUPPORT IN INFECTION MANAGEMENT FOR PHARMACISTS
» ANTIBIOTIC POLICY IN THE TERTIARY CARE CENTRE
» ANTIBIOTIC CONSUMPTION IN ICU S
» ANTIBIOTIC RESISTANCE IN ICU
» The impact of antibiotic policies and antibiotic consumption on antibiotic resistance
» IT and benchmarking to improve antibiotic prescribing
» COST OF HOSPITAL-ACQUIRED INFECTION
» THE COST OF ANTIMICROBIAL RESISTANCE
» Costs of screening/surveillance cultures
» Isolation, cohorting, and contact isolation
» EPIDEMIOLOGY OF INVASIVE FUNGAL INFECTIONS
» Antifungal resistance in Candida species
» Antifungal resistance cannot be transmitted by extrachromosomal DNA
» RATIONAL USE OF ANTIFUNGAL AGENTS
» THE CHANGING FACE OF VIRAL INFECTIONS AND THEIR MANAGEMENT
» PROBLEMS ASSOCIATED WITH ANTIVIRAL THERAPY
» ANTIVIRAL TREATMENT STRATEGIES
» ANTIVIRAL PROPHYLAXIS STRATEGIES
» ANTIBIOTIC CONCENTRATIONS AT TARGET SITES
» An infant with aplastic anaemia
» A long-standing E. coli infection of liver cysts
» BREAKPOINTS: A SHORT HISTORY AND OVERVIEW
» PHARMACODYNAMIC RELATIONSHIPS AND EMERGENCE OF RESISTANCE
» EVALUATION OF THE ANTIMICROBIAL RESISTANCE SURVEILLANCE DATA PUBLISHED IN THE MEDICAL LITERATURE
» PRACTICAL ASPECTS OF THE IMPLEMENTATION OF THE SURVEILLANCE PROGRAM
» Multivariate analysis methods
» Evolutionary genetic approaches
» Study of the relationship between bacterial resistance and antimicrobial consumption
» To predict the short-term evolution of resistance
» To evaluate interventions to control antibiotic resistance
» DISINFECTANTS: TYPES, ACTIONS, AND USAGES
» Evidence of bacterial resistance to biocides
» Mechanisms of bacterial resistance to biocides
» EVIDENCE OF CROSS-RESISTANCE BETWEEN BIOCIDES AND ANTIBIOTICS
» DISINFECTANT USAGE AND ANTIBIOTIC RESISTANCE
» METHODS OF LITERATURE REVIEW
» PROBLEMS WITH INTERPRETATION OF PUBLISHED STUDIES
» Distribution of educational materials
» Audit and feedback with or without other educational materials
» Educational group meetings or seminars
» Educational outreach/academic detailing
» Financial/healthcare system changes
» EFFECT OF INTERVENTIONS ON ANTIBIOTIC RESISTANCE
» DDD/1,000 INHABITANTS AND DAY (DID)
» PRESCRIPTIONS/1,000 INHABITANTS AND YEAR
» INDICATIONS FOR ANTIBIOTIC PRESCRIPTIONS
» POSSIBLE CAUSES FOR OBSERVED VARIATIONS IN ANTIBIOTIC USE
» DETERMINANTS OF ANTIBIOTIC CONSUMPTION
» COLLECTIVE AWAKENING AND PROGRESSIVE MOBILIZATION OF FRENCH PUBLIC HEALTH AUTHORITIES
» ANTIBIOTIC USE AND COST TRENDS
» IMPACT ON HEALTH BUDGETS OF ANTIBIOTIC USE
» ACCESS TO ESSENTIAL ANTIBIOTICS AT ALL LEVELS OF CARE
» EPIDEMIOLOGY OF ANTIMICROBIAL RESISTANCE
» THREAT OF ANTIMICROBIAL RESISTANCE
» ECONOMIC IMPLICATIONS OF ANTIMICROBIAL RESISTANCE
» FACTORS CONTRIBUTING TO DEVELOPMENT AND SPREAD OF RESISTANCE
» STRATEGIES FOR CONTAINMENT OF RESISTANCE IN DEVELOPING COUNTRIES
» Antibacterial resistance and policies
» Policies, guidelines, and education on antibacterial use
» Discovery, development, and commercialization in the face of policies
» Antibacterial development, labelling, and benefits
» WHAT CAN BE DONE NOW ABOUT ANTIBIOTIC RESISTANCE?
» HOW CAN THE DIAGNOSTIC LABORATORY HELP?
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