Pongpun SawatwongPatranuch SapchookulToni WhistlerChristopher J. GregoryOrnuma SangwichianSirirat MakprasertPossawat JorakatePrasong SrisaengchaiSomsak ThamthitiwatChidchanok PromkongPongnapat NanvatthanachodMuthita VanapornJulia RhodesCenters for Disease Control and PreventionThailand Ministry of Public HealthMahidol UniversityNakhon Phanom Provincial HospitalSa Kaeo Crown Prince Hospital2020-01-272020-01-272019-01-01American Journal of Tropical Medicine and Hygiene. Vol.100, No.4 (2019), 943-951000296372-s2.0-85064239509https://repository.li.mahidol.ac.th/handle/123456789/51152© 2019 by The American Society of Tropical Medicine and Hygiene. Bloodstream infection surveillance conducted from 2008 to 2014 in all 20 hospitals in Sa Kaeo and Nakhon Phanom provinces, Thailand, allowed us to look at disease burden, antibiotic susceptibilities, and recurrent infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae. Of 97,832 blood specimens, 3,338 were positive for E. coli and 1,086 for K. pneumoniae. The proportion of E. coli isolates producing ESBLsignificantly increased from19%to22%in 2008-2010 to approximately30%from 2011 to 2014 (P-value for trend = 0.02), whereas ESBL production among K. pneumoniae cases was 27.4% with no significant trend over time. Incidence of community-onset ESBL-producing E. coli increased from 5.4 per 100,000 population in 2008 to 12.8 in 2014, with the highest rates among persons aged ≥ 70 years at 79 cases per 100,000 persons in 2014. From 2008 to 2014, communityonset ESBL-producing K. pneumoniae incidence was 2.7 per 100,000, with a rate of 12.9 among those aged ≥ 70 years. Although most (93.6% of E. coli and 87.6% of K. pneumoniae) infections were community-onset, hospital-onset infections were twice as likely to be ESBL. Population-based surveillance, as described, is vital to accurately monitor emergence and trends in antimicrobial resistance, and in guiding the development of rational antimicrobial therapy recommendations.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.4269/ajtmh.18-0394