scholarly journals Development of a Variable Number of Tandem Repeats Typing Scheme for the Bacterial Rice Pathogen Xanthomonas oryzae pv. oryzicola

2012 ◽  
Vol 102 (10) ◽  
pp. 948-956 ◽  
Author(s):  
Shuai Zhao ◽  
Lucie Poulin ◽  
Luis M. Rodriguez-R ◽  
Natalia Forero Serna ◽  
Shu-Yan Liu ◽  
...  

Xanthomonas oryzae pv. oryzicola is an important bacterial pathogen responsible for outbreaks of bacterial leaf streak (BLS) on rice, mostly occurring in Asia and parts of Africa. To better monitor epidemics and assess population structures, efficient tools that allow the precise identification and diagnosis of pathogenic populations are needed. In this study, we explored variable numbers of tandem repeats (VNTR) as a fast, reliable, and cost-effective molecular typing tool. Screening of three X. oryzae pv. oryzicola genome sequences (Philippine strain BLS256, Chinese strain GX01, and Malian strain MAI10) predicted 28 candidate VNTR loci. Primer pairs for polymerase chain reaction (PCR) amplification of all 28 loci were designed and applied to a panel of 20 X. oryzae pv. oryzicola strains originating from Asia and Africa. Sequencing of PCR amplicons revealed 25 robust and polymorphic VNTR loci that are shared among Asian and African X. oryzae pv. oryzicola strains. A dendrogram constructed from 25 VNTR loci indicated that most Asian strains are clearly discriminated from African strains. However, in agreement with previous reports, one strain from Mali is related to Asian strains, pointing to a possible introduction of Asian strains to the African continent. The new VNTR-based tool described here is useful for studies of population structures and epidemiological monitoring of X. oryzae pv. oryzicola.

2010 ◽  
Vol 58 (3) ◽  
pp. 297-308 ◽  
Author(s):  
Bozidar Savic ◽  
Vojin Ivetic ◽  
Vesna Milicevic ◽  
Ivan Pavlovic ◽  
Milenko Zutic ◽  
...  

Mycoplasma hyopneumoniaeis a primary agent associated with mycoplasma pneumonia and the porcine respiratory disease complex (PRDC). Various reports have indicated that different strains ofM. hyopneumoniaeare circulating in the swine population. Lysates from lung swabs from naturally infected pigs of different ages were tested according to a new variable number of tandem repeats (VNTR) genetic typing method based on the polyserine repeat motif of the P146 lipoproteoadhesin, which can be applied directly on clinical material without isolation ofM. hyopneumoniae. The aim was to determine the diversity ofM. hyopneumoniaeisolates from conventional farrow-to-finish pig farms located in different geographical areas of Serbia. PCR amplification was carried out usingM. hyopneumoniae-specific designed, conserved primers (p146MH — L and p146MH — R) flanking the region encoding the repeat motif, followed by sequencing and cluster analysis. Five groups ofM. hyopneumoniaewith thirteen to twenty-four serine repeats were observed. Analysis of three samples from each farm indicated that the specific isolate is ubiquitous in pigs of different ages. Furthermore, seven clusters were observed within 27 tested samples. The results indicated a considerable diversity amongM. hyopneumoniaefield isolates in the swine population from conventional farrow-to-finish farms in Serbia and suggest close genetic relatedness of the corresponding isolates.


Author(s):  
Arístides López ◽  
Fermin Acosta ◽  
Dilcia Sambrano ◽  
Musharaf Tarajia ◽  
Sophia Navajas ◽  
...  

Mycobacterium tuberculosis (MTB) stands out as the main causative agent of pulmonary tuberculosis (TB). However, nontuberculous mycobacteria (NTM) species also have the potential to infect and cause TB in susceptible individuals. The objective of this study was to identify NTM species that cause public health problems in remote areas. The study was carried out using 105 sputum smears obtained from patients from the Guna Yala Region of Panama with clinical signs suggestive of TB. DNA was extracted from sputum smears. Nontuberculous mycobacteria and MTB were characterized using polymerase chain reaction restriction analysis (hsp65, rpob) and an evaluation of 24-mycobacterial interspersed repetitive units–variable number of tandem repeats loci. Twenty-six Mycobacterium species were characterized; 19 (18%) were identified as MTB, and 7 (6.7%) were identified as NTM (four M. avium complex, two M. haemophilum, one M. tusciae). These results suggest that at least one in five cases of pulmonary TB among this population is caused by an NTM. Thus, identifying the bacteria causing pulmonary disease is key even in remote regions of the world where standard diagnosis and culture are not available. Strengthening the laboratory capacity within the Guna Yala Region is needed to identify NTM infections promptly.


2008 ◽  
Vol 35 (12) ◽  
pp. 2325-2328 ◽  
Author(s):  
THAIS B. de SOUZA ◽  
ELISA F. MENTZ ◽  
CLAITON V. BRENOL ◽  
RICARDO M. XAVIER ◽  
JOÃO C.T. BRENOL ◽  
...  

ObjectiveGenetic and environmental factors seem to be involved in the onset of rheumatoid arthritis (RA). We analyzed whether a variable number of tandem repeats (VNTR) polymorphism in the aggrecan gene was associated to RA.MethodsThe study population comprised 170 European-derived Brazilian patients with diagnosis of RA. The control group comprised 148 European-derived Brazilian healthy blood donors. The aggrecan VNTR polymorphism was genotyped by DNA amplification by polymerase chain reaction, followed by electrophoresis in polyacrylamide gel.ResultsThere was a statistically significant higher frequency of alleles of shorter length in the patient group compared to controls (p = 0.001), suggesting that individuals carrying short alleles are more likely to develop RA. There was no association between short alleles and clinical characteristics of RA.ConclusionOur results provide evidence of an association between the aggrecan gene VNTR polymorphism and RA.


2014 ◽  
Vol 143 (5) ◽  
pp. 966-974 ◽  
Author(s):  
S. BARANDIARAN ◽  
A. M. PÉREZ ◽  
A. K. GIOFFRÉ ◽  
M. MARTÍNEZ VIVOT ◽  
A. A. CATALDI ◽  
...  

SUMMARYIn Argentina little is known about the epidemiology of tuberculosis (TB) infection in swine. We characterized the epidemiological dynamics ofMycobacterium aviumcomplex (MAC) infection in a swine population of Argentina using molecular tools and spatial analysis techniques. Isolates (n = 196) obtained from TB-like lesions (n = 200) were characterized by polymerase chain reaction. The isolates were positive to eitherM. bovis(IS6110) (n = 160) orM. avium(IS1245) (n= 16) while the remaining 20 (10·2%) isolates were positive to bothM. bovisandM. avium. The detection of both bacteria together suggests co-infection at the animal level. In addition, MAC-positive isolates (n = 36) were classified asM. aviumsubsp.avium(MAA) (n = 30) andM. aviumsubsp.hominissuis(MAH) (n = 6), which resulted in five genotypes when they were typed using mycobacterial interspersed repetitive unit, variable number of tandem repeats (MIRU-VNTR). One significant (P = 0·017) spatial clustering of genotypes was detected, in which the proportion of MAH isolates was larger than expected under the null hypothesis of even distribution of genotypes. These results show that in Argentina the proportion of TB cases in pigs caused byM. aviumis larger than that reported in earlier studies. The proportion ofM. bovis–MAC co-infections was also higher than in previous reports. These results provide valuable information on the epidemiology of MAC infection in swine in Argentina.


2010 ◽  
Vol 59 (3) ◽  
pp. 285-294 ◽  
Author(s):  
Jian Zhang ◽  
Edgar Abadia ◽  
Guislaine Refregier ◽  
Silva Tafaj ◽  
Maria Laura Boschiroli ◽  
...  

The aims of the present study were to implement a microbead-based ‘spoligotyping’ technique and to evaluate improvements by the addition of a panel of 25 extra spacers that we expected to provide an increased resolution on principal genetic group 1 (PGG 1) strains. We confirmed the high sensitivity and reproducibility of the classical technique using the 43 spacer panel and we obtained perfect agreement between the membrane-based and the microbead-based techniques. We further demonstrated an increase in the discriminative power of an extended 68 spacer format for differentiation of PGG 1 clinical isolates, in particular for the East African–Indian clade. Finally, we define a limited yet highly informative reduced 10 spacer panel set which could offer a more cost-effective option for implementation in resource-limited countries and that could decrease the need for additional VNTR (variable number of tandem repeats) genotyping work in molecular epidemiological studies. We also present an economic analysis comparing membrane-based and microbead-based techniques.


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