Specific Multilocus Variable-Number Tandem-Repeat Analysis Genotypes of Mycoplasma pneumoniae Are Associated with Diseases Severity and Macrolide Susceptibility

Jiuxin Qu,Xiaomin Yu,Yudong Yin,Yingmei Liu,Li Gu,Chen Wang,Bin Cao,Mitchell F Balish

doi:10.1371/journal.pone.0082174

Abstract

Clinical relevance of multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) in patients with community-acquired pneumonia (CAP) by Mycoplasma pneumoniae (M. pneumoniae) is unknown. A multi-center, prospective study was conducted from November 2010 to April 2012. Nine hundred and fifty-four CAP patients were consecutively enrolled. M. pneumoniae clinical isolates were obtained from throat swabs. MLVA typing was applied to all isolates. Comparison of pneumonia severity index (PSI) and clinical features among patients infected with different MLVA types of M. pneumoniae were conducted. One hundred and thirty-six patients were positive with M. pneumoniae culture. The clinical isolates were clustered into 18 MLVA types. One hundred and fourteen (88.3%) isolates were resistant to macrolide, covering major MLVA types. The macrolide non-resistant rate of M. pneumoniae isolates with Mpn13-14-15-16 profile of 3-5-6-2 was significantly higher than that of other types (p≤0.001). Patients infected with types U (5-4-5-7-2) and J (3-4-5-7-2) had significantly higher PSI scores (p<0.001) and longer total duration of cough (p = 0.011). Therefore it seems that there is a correlation between certain MLVA types and clinical severity of disease and the presence of macrolide resistance.

Highlights

Mycoplasma pneumoniae (M. pneumoniae) is a common and important pathogen of community-acquired pneumonia (CAP), accounting for 10%–30% of cases [1,2,3,4]
The variable-number tandem-repeat (VNTR) locus Mpn1 is reported to be unstable in both clinical isolates and in laboratory passages, multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) genotyping of M. pneumoniae still exceeds the discriminatory power of previous typing methods based on P1 gene [8,9]
Cough was more common in M. pneumoniae pneumonia patients

Summary

Introduction

Mycoplasma pneumoniae (M. pneumoniae) is a common and important pathogen of community-acquired pneumonia (CAP), accounting for 10%–30% of cases [1,2,3,4]. Isolates are not well differentiated using the most common typing methods based on the analysis of the gene encoding the P1 protein [5,6]. In 2009, Dégrange et al have established the multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) method based on 5. VNTRs as Mpn, and clustered 265 M. pneumoniae clinical isolates into 26 MLVA types [7]. In 2011, the same group has successfully confirmed a single-clone spread of type J (3-4-5-72) M. pneumoniae among children in a French primary school and their household contacts. The VNTR locus Mpn is reported to be unstable in both clinical isolates and in laboratory passages, MLVA genotyping of M. pneumoniae still exceeds the discriminatory power of previous typing methods based on P1 gene [8,9]. Macrolide-resistant M. pneumoniae have been spreading for 10 years worldwide, with prevalences ranging from below 10% in PLOS ONE | www.plosone.org

Materials and Methods

Results

Discussion

Methods