Background Detecting pathogen from the culturing cerebrospinal fluid (CSF) is the golden standard for the diagnosis of intracranial infection. At present, blood culture bottles are commonly used to culture CSF samples, and subculture is adopted for positive ones before pathogen identification and antimicrobial susceptibility testing, which is time-consuming and unavailable for timely diagnosis and treatment. So it is necessary to increase the report efficient by refining the process.
Objective To explore the accuracy and efficiency of the species identification and antimicrobial susceptibility testing of positive samples after rapidly culturing by HB&L (Human biological fluid) microbial culture system.
Methods A total of 37 CSF positive samples were collected in the Sixth Medical Center of Chinese PLA General Hospital from January 2021 to January 2022. These samples were processed with the conventional isolation culture method and HB&L rapid culture method, respectively. Then the species identification and antimicrobial susceptibility test were performed with MALDI-TOF MS and VITEK-2 Compact system. The conventional culture method was defined as golden standard and the accuracy of identification and coincidence rate of antimicrobial susceptibility testing were assessed, as well as the turnaround time of the two methods.
Results Totally 37 strains were isolated and identified, including coagulase-negative Staphylococci (11 strains), S.aureus (1 strains), E.faecali s (1 strains), Corynebacterium striatum (2 strains), Bacillus cereus (1 strains), A.baumannii (6 strains), K.pneumoniae (6 strains), P.aeruginosa (3 strains), E.coli (2 strains), E.cloacae (1 strains), S.maltophilia (1 strains) and fungus (2 strains). The identification accuracy of the HB&L rapid culture method was 100.00%. Compared with the conventional culture method, the antimicrobial susceptibility test coincidence rate of HB&L rapid culture method for Gram-negative bacteria was 100.00%, except for tegacyclin, amikacin and minocycline with the coincidence rate of 94.44%. The antimicrobial susceptibility test coincidence rate of Gram-positive bacteria was 100.00%, except for erythromycin with the coincidence rate of 92.31%. The total coincidence rate of the antimicrobial susceptibility test was 98.90%, with MIE of 0.82%, ME of 0.00% and VME of 0.27%. The turnaround time of species identification and antimicrobial susceptibility test of HB&L rapid culture method were 22.10 h and 24.77 h, which were shorter than those of conventional method (P＜0.001, respectively).
Conclusion The HB&L system, combining with MALDI-TOF MS and VITEK-2 Compact system, can be used in species identification and antimicrobial susceptibility testing of the positive CSF samples, which can provide evidences for clinical timely treatment by shortening the report time.
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