Surveillance of antimicrobial resistance Liselotte Högberg Swedish Institute for Infectious Disease Control

OVERVIEW Basic principles Why, what, how and who? Antimicrobial surveillance in Sweden Different types of surveillance Validity of surveillance data Sensitivity, specificity

WHY? - Defining/updating treatment guidelines - Identifying needs for infection control measures - Monitoring the impact of interventions to improve antimicrobial use and control spread of infection Basic principles

Should be focused on pathogens of greatest public health importance Should include pathogens that are readily transmissible Should provide information for action at local and national levels WHAT?

Basic principles HOW ? Comprehensive surveillance Sentinel surveillance Point-prevalence studies

Basic principles Comprehensive surveillance - Includes the whole population at risk - Aiming to capture all cases - Involves large number of clinicians and laboratories – only limited set of data

Basic principles Sentinel surveillance - Indicator data for rest of population - Suitable when prolonged and detailed data is required - Target approach (instead of representative sample) might be suitable

Basic principles Point prevalence studies - Useful for validation of representativity of surveillance data - Evaluation of interventions

Basic principles WHO ? General population vs. hospital in-patients Clinical reports Laboratory reports

Basic principles Clinical data Laboratory data + timely information on clinical disease + possibility to get detailed patient information - dependent on accuracy and consistency in diagnosis and timely and complete reporting + objective confirmation of the diagnosis + opportunity for detailed characterisation of the causative organism - less timely - often few clinical details DATA SOURCE

Numerators for surveillance Data should relate to a single episode of illness in a patient Microbiological data: only the first positive culture from the patient from each disease episode should be reported Microbiological data: qualitative or quantitative Basic principles

Examples of antimicrobial surveillance projects ANNUAL REPORTS DANMAP – Denmark FIRE – Finland NORM – Norway SWEDRES – Sweden EARSS ( RESEARCH/INDUSTRY INITATIVES Alexander project Sentry Basic principles

Examples of antimicrobial surveillance systems ANNUAL REPORTS DANMAP – Denmark FIRE – Finland NORM – Norway SWEDRES – Sweden EARSS ( RESEARCH/INDUSTRY INTITATIVES Alexander project Sentry Basic principles

AMR surveillance in Sweden Antimicrobial resistance surveillance in Sweden 1. Mandatory case notification 2. Annual resistance surveillance and quality control programme (RSQC) 3. Sentinel surveillance 4. EARSS

AMR surveillance in Sweden Antimicrobial resistance surveillance in Sweden Mandatory case notification Comprehensive surveillance of all cases of MRSA, VRE and penicillin-resistant pneumococci (PRP) to the Swedish Institute for Infectious Disease Control Mandatory for both the clinician having seen the patient and the laboratory diagnosing the pathogen Basic patient data: age, sex, place of residence Data presented as incidence figures (population denominator)

AMR surveillance in Sweden Antimicrobial resistance surveillance in Sweden Annual resistance surveillance and quality control programme (RSQC) Each laboratory report resistance data for at least 100 consecutive bacteria per year Includes S. pneumoniae, S. aureus, E. coli, S. pyogenes, H. pylori, E. faecalis/faecium No patient data avilable Detailed resistance data Data presented as proportion (% resistant isolates/ all isolates)

AMR surveillance in Sweden Antimicrobial resistance surveillance in Sweden Sentinel surveillance Data mainly derived from special investigations by devoted laboratories At present includes salmonella, shigella, campylobacter, N. gonorrhoeae, N. meningitidis Quality of data varies

AMR surveillance in Sweden Antimicrobial resistance surveillance in Sweden EARSS Funded by DG SANCO of the European Commission Surveillance of antmicrobial susceptibility of invasive infections of S. aureus, S. pneumoniea, E. coli, E. faecalis/faecium 27 countries participates

EARSS: Proportion PRP isolates in year 2000

AMR surveillance in Sweden INFORMATION FEEDBACK ResNet ( Electronic database containing data from RSQC, EARSS and sentinel surveillance SwedRes ( Annual report on Swedish antibiotic utilisation and resistance in human and veterinary medicine

Data validity PRP (penicillin-resistant pneumococci) Streptococcus pneumoniae MIC PcG >= 0,5 mg/L Notifiable in Sweden since 1996 Increasing resistance problem internationally Surveillance data available from mandatory data, RSQC and EARSS

Data validity Incidence/ inh (PRP MIC PcG >= 0,5 mg/L)

Data validity Incidence/ inh (PRP MIC PcG >= 0,5 mg/L) RSQC rate (PRP MIC >= 0,12 mg/L)

Data validity Incidence/ inh (PRP MIC PcG >= 0,5 mg/L) RSQC rate (PRP MIC >= 0,12 mg/L) EARSS rate (Invasive PRP >= 0,12 mg/L)

Data validity Incidence/ inh (PRP MIC PcG >= 0,5 mg/L) RSQC rate (PRP MIC >= 0,12 mg/L) EARSS rate (Invasive PRP >= 0,12 mg/L) PRP rate (PRP MIC PcG >= 0,5 mg/L)

Data validity Nasopharyngeal cultures/1000 inhabitants in Sweden

Changes in culturing propensity Data validity

Ideal surveillance data Maximum specificity –Limit false positives Maximum sensitivity –Captures all true positives –Determination of break-points at laboratories –Transient nasal carriage (MRSA) Data validity

Specificity Methodological problems at the laboratory Reporting bias from laboratories Data validity

Determinants for sensitivity 1.Contact with health care services 2. The pathogen is isolated 3.The case is reported There is a risk for bias in each step! Data validity

Contact with health care services Accessibility –Better access to physicians in large cities Costs –Free health care for children, cost recovery systems Socio - economy, tradition Screening/contact tracing initiatives Data validity

Routines for contact tracing for PRP MIC PcG > 0,5 mg/L Multi-resistance or high MIC-values Individual

Isolation of the pathogen Cultures from all cases/only on therapeutic failures? Tradition in culturing propensity Economical obstacles Fear of time-consuming contact tracing Data validity

Nasopharyngeal culturing propensity in Sweden (Number of nasopharyngeal cultures/1000 inhabitants) Data validity

Who is sampled? Carriage Disease Antibiotic treatment Treatment failure Data validity

PRP incidence/1000 inhabitants (all cases) in area G and M Data validity

PRP incidence (only index cases) in area G and M Data validity

Summary: Basic principles Obtaining appropriate specimens from the infected individual Successful isolation of the causative organisms Accurate determination of antimicrobial resistance Data collection, collation and analysis Dissemination of appropriate information for action Summary