Genotyping and clinical characteristics of multidrug and extensively drug-resistant tuberculosis in a tertiary care tuberculosis hospital in China

Abstract

BackgroundThere is a lack of information on the clinical characteristics of multidrug-resistant (MDR) tuberculosis (TB) and extensively drug-resistant (XDR) TB in the Jiangxi Province of China; furthermore, data have not been reported on the utility of mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) analyses in genotyping Mycobacterium tuberculosis strains isolated from this region. The aim of this study was to analyse the clinical features of patients with MDR and XDR TB from Jiangxi Province and to evaluate the discriminatory power of the 15-loci MIRU-VNTR method.MethodsA retrospective study was conducted on patients diagnosed with MDR and XDR TB at the Jiangxi Chest Hospital from July 2010 to June 2011. The RD105 deletion-targeted multiplex PCR (DTM-PCR) and the 15-loci MIRU-VNTR method were used to determine the genetic background of the identified MDR and XDR M. tuberculosis clinical isolates.ResultsOf 804 M. tuberculosis clinical isolates, 159 (159/804, 19.8%) of the isolates were identified as MDR with first-line drug susceptibility testing. Of the 123 available MDR isolates, 13 (13/123, 10.6%) were XDR. The RD105 deletion-targeted multiplex PCR method identified 85 (85/110, 77.3%) MDR and 12 (12/13, 92.3%) XDR isolates as the Beijing genotype. MIRU-VNTR cluster analysis demonstrated that 101 MDR and 13 XDR strains had unique genotype patterns; the remaining 9 MDR strains were in 4 clusters, namely 1 cluster with 3 strains and 3 clusters with 2 strains, resulting in a low clustering rate (4.06%). The Hunter-Gaston discriminatory index (HGDI) of the 15-loci MIRU-VNTR method was as high as 0.992. In addition, clinical surveys showed that 87 (87/110, 79.1%) MDR TB patients and 10 (10/13, 76.9%) XDR TB patients had been previously treated. Diabetes mellitus was the most common comorbidity in both MDR TB (16/110, 14.5%) and XDR TB (2/13, 15.4%) patients.ConclusionsBased on our preliminary data, the MDR and XDR M. tuberculosis clinical isolates identified at the Jiangxi Chest Hospital were genetically diverse and clustered at a low frequency. The 15-loci MIRU-VNTR method showed high discriminatory power and may be used as a first-line genotyping tool in investigating the molecular epidemiology of M. tuberculosis in Jiangxi, China. Decisive measures are urgently needed to effectively prevent and manage MDR and XDR tuberculosis in this province.

Clinical Features and Analysis of Two Patients with Novel Influenza; H7N9 Virus in Taizhou City, China, 2014

“…In previous studies, researchers showed that IFITM3 played a critical role in the response of the immune system to influenza viruses, patients with the rs12252-C/C genotype of IFITM3 had more severe disease symptoms and worse clinical outcomes than the ones with T/T or T/C genotype (4,5,9). In the current study, both of the patients carried the T/C genotype, and their clinical outcomes were mild and 2…”

“…Previous studies showed strong correlation between the IFITM3 and disease severity following influenza virus infection (4,5). For example, the presence of SNP IFITM3-rs12252 has direct correlation with the severity of the diseases associated with H7N9 infection (4).…”

“…To address this issue, the 300-nucleotide-long region of the IFITM3 locus encompassing SNP rs12252 was sequenced in the patient. Genomic DNA was extracted from 500 UL of whole blood using the BloodGen Mini Kit (CW2087, CWbio, China), and the region of IFITM3 containing rs12252 was amplified by polymerase chain reaction (PCR) with primers, as described in previous studies (5). The PCR products were purified and then subsequently subjected to bi-directional DNA sequencing in Invitrogen, Inc. (Shanghai, China).…”

Nontuberculous mycobacterial osteomyelitis

“…Reports of NTM osteomyelitis in DM patients are rare, but given the recent increase in identification of NTM as pathogens, the possibility of NTM osteomyelitis in DM patients is worthy of more attention. DM can affect cytokine levels, chemotaxis and phagocytosis of monocytes and macrophages, and can cause an abnormal delayed-type hypersensitivity response [ 186 ]. These effects are particularly serious in elderly patients with DM, and may increase the risk of intracellular infections with pathogens such as NTM and tuberculosis [ 186 ].…”

“…DM can affect cytokine levels, chemotaxis and phagocytosis of monocytes and macrophages, and can cause an abnormal delayed-type hypersensitivity response [ 186 ]. These effects are particularly serious in elderly patients with DM, and may increase the risk of intracellular infections with pathogens such as NTM and tuberculosis [ 186 ]. Osteomyelitis is a complication of DM, and is associated with increased mortality, as well as increased costs [ 187 ].…”