Bacterial Genomics for National Antimicrobial Resistance Surveillance in Cambodia.

BACKGROUND: Antimicrobial resistance (AMR) surveillance in low- and middle-income countries (LMICs) often relies on poorly resourced laboratory processes. Centralized sequencing was combined with cloud-based, open-source bioinformatics solutions for national AMR surveillance in Cambodia. METHODS: Blood cultures growing gram-negative bacteria were collected at six Cambodian hospitals (January 2021 - October 2022). Isolates were obtained from pure plate growth and shotgun DNA sequencing performed in-country. Using public nucleotide and protein databases, reads were aligned for pathogen identification and AMR gene characterization. Multilocus sequence typing was performed on whole genome assemblies and haplotype clusters compared against published genomes. FINDINGS: Genes associated with acquired resistance to fluoroquinolones were identified in 59%, TMP/SMX in 45%, and aminoglycosides in 52% of 715 isolates. Extended-spectrum beta-lactamase encoding genes were identified in 34% isolates, most commonly blaCTX-M-15, blaCTX-M-27, and blaCTX-M-55 in E. coli sequence types 131 and 1193. Carbapenemase genes were identified in 12% isolates, most commonly blaOXA-23, blaNDM-1, blaOXA-58 and blaOXA-66 in Acinetobacter species. Phylogenetic analysis revealed clonal strains of A. baumannii, representing suspected nosocomial outbreaks, and genetic clusters of quinolone-resistant typhoidal Salmonella and ESBL E. coli cases suggesting community transmission. INTERPRETATION: With accessible sequencing platforms and bioinformatics solutions, bacterial genomics can supplement AMR surveillance in LMICs. FUNDING: Research was supported by the National Institute of Allergy and Infectious Diseases and the Bill and Melinda Gates Foundation [OPP1211806].

Case Report: Risk Factors Associated with Mortality in Adults with Burkholderia Pseudomallei Bacteremia: A Retrospective Case Series of Melioidosis in Cambodia.

In resource-scarce settings, melioidosis is associated with up to 80% mortality. Studies of melioidosis in Cambodia report primarily on pediatric populations with localized infection; however, literature describing Cambodian adults with severe melioidosis is lacking. We present a case series of 35 adults with sequence-confirmed Burkholderia pseudomallei bacteremia presenting to a provincial referral hospital in rural Cambodia. More than 90% of the patients had diabetes, an important risk factor for developing melioidosis. Inappropriate antimicrobial therapy was significantly associated with lower odds of survival. Improved diagnostic testing and greater access to first-line antibiotics for acute melioidosis treatment present potential targets for intervention to reduce mortality associated with this disease in resource-limited settings.

Neonatal Sepsis Epidemiology in a Rural Province in Southeastern Cambodia, 2015-2017.

Neonatal sepsis is the second most prevalent cause of neonatal deaths in low- and middle-income countries, and many countries lack epidemiologic data on the local causes of neonatal sepsis. During April 2015-November 2016, we prospectively collected 128 blood cultures from neonates admitted with clinical sepsis to the provincial hospital in Takeo, Cambodia, to describe the local epidemiology. Two percent (n = 3) of positive blood cultures identified were Gram-negative bacilli (GNB) and were presumed pathogens, whereas 10% (n = 13) of positive blood cultures identified were likely contaminants, consistent with findings in other published studies. No group B Streptococcus was identified in any positive cultures. The presence of GNB as the primary pathogens could help influence local treatment guidelines.