Identification and resistance characteristics of CAMP-negative Streptococcus agalactiae
10.19405/j.cnki.issn1000-1492.2025.01.020
- Author:
Xiu Wang
1
;
Guiyun Leng
1
;
Wei Tang
1
;
Qiang Zhou
1
Author Information
1. Dept of Clinical Laboratory，The Second Affiliated Hospital of Anhui Medical University，Hefei 230601
- Publication Type:Journal Article
- Keywords:
Streptococcus agalactiae;
MALDI-TOF MS;
CAMP assay;
16S rDNA;
qPCR;
cfb
- From:
Acta Universitatis Medicinalis Anhui
2025;60(1):142-146
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore identification and resistance characteristics of CAMP-negativeStreptococcus agalactiae.
Methods :Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS) and the CAMP assay, 33 presumptive strains ofStreptococcus agalactiaewere identified. The CAMP-negative strains were further validated through 16S rDNA, while the CAMP factor encoding gene(cfb) was detected using real-time fluorescence quantitative polymerase chain reaction(qPCR). Antimicrobial susceptibility testing was conducted using the microbroth dilution method, and the resistance rates of CAMP-negative and CAMP-positive strains were compared.
Results :Based on MALDI-TOF MS identification, all 33 strains were classified asStreptococcus agalactiae. Among them, 7 strains tested negative for CAMP were subsequently confirmed asStreptococcus agalactiaethrough 16S rDNA. The qPCR results indicated that, only 1 strain showedcfbpresence. The CAMP-negative and CAMP-positive strains were sensitive to penicillin G, cefepime, cefotaxime, vancomycin, and linezolid. The resistance rates of the former to chloramphenicol and tetracycline(28.57%, 85.71%) were slightly higher than the latter(15.38%, 57.69%), while the resistance rates to moxifloxacin, levofloxacin, and erythromycin(14.29%, 14.29%, 42.86%) were slightly lower than the latter(34.62%, 34.62%, 57.69%), but was not significant.
Conclusion:Drug risistance of CAMP-negativeStreptococcus agalactiaeis the same as CAMP-positive strains, but traditional CAMP assay andcfb-targeted qPCR can result in missed detections. MALDI-TOF MS offers a quick, simple, and accurate identification method that merits wider adoption.
- Full text:202601211710257424CAMP阴性无乳链球菌的鉴定及耐药特征_王秀.pdf
