Evaluation of a new chromogenic media for the isolation and culture of Clostridium difficile
10.13602/j.cnki.jcls.2019.04.15
- VernacularTitle:一种用于艰难梭菌分离培养的新型显色培养基的性能评价
- Author:
Qiao BIAN
1
,
2
;
Yun LUO
3
;
Xingxing XU
4
;
Xiaojun SONG
3
;
Julian YE
3
;
Jianmin JIANG
3
,
5
;
Dazhi JIN
3
,
5
Author Information
1. School of Medicine, Ningbo University
2. Departments of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention
3. Departments of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention
4. Department of Laboratory Medicine, Hangzhou First Hospital affiliated with Zhejiang Chinese Medical University
5. Key Laboratory of Vaccine, Prevention and Control of Infectious Disease of Zhejiang Province
- Publication Type:Journal Article
- Keywords:
Clostridium difficile;
chromogenic medium;
performance evaluation
- From:
Chinese Journal of Clinical Laboratory Science
2019;37(4):301-304
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the performance of a chromogenic agar developed by our laboratory for the isolation and culture of Clostridium difficile (CDCA).
Methods:The chromogenic specificity of CDCA was evaluated by inoculation of C. difficile and other standard strains, and the sensitivities of CDSA (BD), CDIF (BioMérieux) and CDCA were determined by the C. difficile standard strains respectively. A total of 120 clinical stool specimens were cultured for C. difficile by three chromogenic media respectively. The colonies were further identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and tpi gene was also detected. The sample which could be identified as C. difficile in any of the three chromogenic medium was defined as true positive.
Results:Most of standard strains were inhibited by CDCA, however some Clostridium species including C. clostridiiforme, C. bifermentans, C. tertium and Bacteroides fragilis grew lightly with chromogenic reaction. The sensitivities of CDSA, CDIF and CDCA were 2.0×105 CFU/mL, 8.0×101 CFU/mL and 4.0×10 2 CFU/mL, respectively. Among the 120 samples, 31 (25.8%) were defined as true C. difficile positive samples, while the positive rate of CDSA, CDIF and CDCA were 25 (20.8%), 28 (23.3%) and 26 (21.7%), respectively. There was no significant difference for clinical diarrhea specimens among the three chromogenic media (χ 2 =0.418, P=0.811). In comparison to the standard, the sensitivity, specificity, positive predictive value and negative predictive value were 83.8%, 100%, 100% and 94.7% for CDCA; 90.3%, 98.9%, 96.6% and 96.7% for CDIF; and 80.6%, 100%, 100% and 93.7% for CDSA.
Conclusion:The CDCA developed by our laboratory could be used to preliminarily isolate C. difficile with good specificity and sensitivity.
