Antimicrobial resistance surveillance: can we estimate resistance in bloodstream infections from other types of specimen?
Vihta K-D., Gordon NC., Stoesser N., Quan TP., Tyrrell CSB., Vongsouvath M., Ashley EA., Chansamouth V., Turner P., Ling CL., Eyre D., White NJ., Crook D., Peto T., Walker AS.
SynopsisBackgroundAntimicrobial resistance (AMR) surveillance of bloodstream infections is challenging in low- and middle-income countries (LMICs), limited laboratory capacity preventing routine patient-level susceptibility testing. Other specimen types could provide an effective approach to surveillance.ObjectivesOur study aims to systematically evaluate the relationship between resistance prevalence in non-sterile sites and bloodstream infections.MethodsAssociations between resistance rates in Escherichia coli and Staphylococcus aureus isolates from blood and other specimens were estimated in Oxfordshire, UK, 1998-2018, comparing proportions resistant in each calendar year using time series cross-correlations and across drug-years. We repeated analysis across publicly-available data from four high-income and 12 middle-income countries, and in three hospitals/programmes in LMICs.Results8102 E. coli bloodstream infections, 322087 E. coli urinary tract infections, 6952 S. aureus bloodstream infections and 112074 S. aureus non-sterile site cultures were included from Oxfordshire. Resistance trends over time in blood versus other specimens were strongly correlated (maximum cross-correlation 0.51-0.99, strongest associations in the same year for 18/27 pathogen-drug combinations). Resistance prevalence was broadly congruent across drug-years for each species. 276/312 (88%) species-drug-years had resistance prevalence in other specimen types within ±10% of that blood isolates. Results were similar across multiple countries and hospitals/programmes in high/middle/low income-settings.ConclusionsResistance in bloodstream and less invasive infections are strongly related over time, suggesting the latter could be a surveillance tool for AMR in LMICs. These infection sites are easier to sample and cheaper to obtain the necessary numbers of susceptibility tests, providing more cost-effective evidence for decisions including empiric antibiotic recommendations.