Abstract
BackgroundPulmonary infections caused by non-diphtheriae corynebacteria are increasing. However, rapid identification of Corynebacterium species poses a challenge due to the low genetic variation within the genus.MethodsThree reference strains and 99 clinical isolates were used in this study. A qPCR followed by high-resolution melting (HRM) targeting ssrA was performed to simultaneously identify C. striatum, C. propinquum and C. simulans. To further evaluate this assay’s performance, 88 clinical sputum samples were tested by HRM and the detection results were compared with those of the traditional culture method and multiple cross-displacement amplification (MCDA) assay.ResultsThe melting curve produced by a pair of universal primers generated species-specific HRM curve profiles and could distinguish the three target species from other related bacteria. The limit of detection of HRM assay for DNA from the three purified Corynebacterium species was 100 fg. Compared with the culture method, HRM detected 22 additional positive specimens, representing a 23.9% relative increase in detection rate. The HRM assay had 98.4% (95% confidence interval [CI], 90.5–99.9%) sensitivity and 100% (95% CI, 82.8–100%) specificity. Additionally, 95.5% concordance between HRM and MCDA (κ = 0.89 [95% CI, 0.79–0.99]) was noted.ConclusionsThe HRM assay was a simple, rapid, sensitive, and specific diagnostic tool for detecting C. striatum, C. propinquum, and C. simulans, with the potential to contribute to early diagnosis, epidemiological surveillance, and rapid response to outbreak.
Highlights
Pulmonary infections caused by non-diphtheriae corynebacteria are increasing
We report the development of a quantitative real-time polymerase chain reaction (qPCR)– based highresolution melting (HRM) assay capable of detecting C. striatum, C. propinquum, and C. simulans, as well as distinguishing between them in pure cultures and clinical specimens with increased specificity and sensitivity
HRM analysis for identification of C. striatum, C. propinquum, and C. simulans A pair of universal primers, designed to detect C. striatum, C. propinquum, and C. simulans in HRM analysis, amplified fragments of 233, 240, and 233 bp, respectively, for these species
Summary
Pulmonary infections caused by non-diphtheriae corynebacteria are increasing. Rapid identification of Corynebacterium species poses a challenge due to the low genetic variation within the genus. In recent years, there has been a considerable increase in reports of non-diphtheriae Corynebacterium species, which have been linked to multiple hospital outbreaks and nosocomial infections [2,3,4]. These microorganisms are common components of the skin microbiota and mucous membranes, their clinical significance as emerging respiratory pathogens has been demonstrated by various studies [4,5,6]. Detection and identification of Corynebacterium species are essential to intervention and infection treatment efforts
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