The comparison of nanopore sequencing and antimicrobial susceptibility standard test in diagnosis of carbapenem-resistant enterobacteriaceae in urinary tract infection in King Chulalongkorn Memorial hospital
Abstract:
Objective To evaluate the sensitivity and the specificity of Nanopore sequencing against the standard (culture) method in bacterial identification and antibiotic resistance profiling from direct urine specimens. Methods Bacterial cells were enriched from direct urine specimens by differential centrifugation to decrease the number of human cells. DNA was extracted from bacterial pellets and the purified DNA was then sequenced by Nanopore sequencing (MinION) to identify the organisms and drug resistance genes in comparison to the results of routine urine cultures and standard antibiotic susceptibility tests. Results 60 specimens of Enterobacteriaceae were identified from routine urine, including the phenotypes of 28 carbapenem-resistant Enterobacteriaceae (CRE), 16 extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae, and 16 non-CRE/non-ESBL/non-Amp-C. Excluding 7 specimens with low DNA amount (< 1 ng/mcl), sensitivity for carbapenemase genes and ESBL/AmpC genes detection by Nanopore sequencing are 86.9% (66.4-97.2%; 95%CI) and 92.1% (78.6-98.3%; 95%CI), respectively. Specificity for carbapenemase genes and ESBL/AmpC genes detection by Nanopore sequencing are 93.3% (77.9-99.1%; 95%CI) and 60% (32.3-83.4%; 95%CI),respectively. Conclusion Nanopore sequencing identified pathogens and their resistance genes from urine in timeframe similar to polymerase chain reaction (median time 3.5 (2.2-8.2) hours from samples to results). More samples are needed for protocol and bioinformatic pipeline optimization to detect the resistances better and faster. Metagenomic sequencing based diagnosis will enable clinicians to adjust antimicrobial therapy before the second-third dose of most antibiotics (every 8-12 hours).