scholarly journals Study of genetic diversity of Salmonella typhi using pulsed-field gel electrophoresis

2001 ◽  
pp. 158 ◽  
Author(s):  
Lucky H. Moehario ◽  
Retno K. Soemanto
2011 ◽  
Vol 5 (S1) ◽  
Author(s):  
Mohsen Ghafari ◽  
Bita Bakhshi ◽  
Mohamad Reza Pour Shafi ◽  
Nour Amir Mozafari ◽  
Mona Salimi ◽  
...  

2008 ◽  
Vol 76 (11) ◽  
pp. 5221-5227 ◽  
Author(s):  
Sarah W. Satola ◽  
Brooke Napier ◽  
Monica M. Farley

ABSTRACT A subset of invasive nontypeable Haemophilus influenzae (NTHI) strains has evidence of IS1016, an insertion element associated with division I H. influenzae capsule serotypes. We examined IS1016-positive invasive NTHI isolates collected as part of Active Bacterial Core Surveillance within the Georgia Emerging Infections Program for the presence or absence of hmw1 and hmw2 (two related adhesin genes that are common in NTHI but absent in encapsulated H. influenzae) and hia (homologue of hsf, an encapsulated H. influenzae adhesin gene). Isolates were serotyped using slide agglutination, confirmed as NTHI strains using PCR capsule typing, and biotyped. Two hundred twenty-nine invasive NTHI isolates collected between August 1998 and December 2006 were screened for IS1016; 22/229 (9.6%) were positive. Nineteen of 201 previously identified IS1016-positive invasive NTHI isolates collected between January 1989 and July 1998 were also examined. Forty-one IS1016-positive and 56 randomly selected IS1016-negative invasive NTHI strains were examined. The hia adhesin was present in 39 of 41 (95%) IS1016-positive NTHI strains and 1 of 56 (1.8%) IS1016-negative NTHI strains tested; hmw (hmw1, hmw2, or both) was present in 50 of 56 (89%) IS1016-negative NTHI isolates but in only 5 of 41 (12%; all hmw2) IS1016-positive NTHI isolates. IS1016-positive NTHI strains were more often biotype V (P < 0.001) or biotype I (P = 0.04) than IS1016-negative NTHI strains, which were most often biotype II. Pulsed-field gel electrophoresis revealed the expected genetic diversity of NTHI with some clustering based on IS1016, hmw or hia, and biotypes. A significant association of IS1016 with biotypes V and I and the presence of hia adhesins was found among invasive NTHI. IS1016-positive NTHI strains may represent a unique subset of NTHI strains, with characteristics more closely resembling those of encapsulated H. influenzae.


2015 ◽  
Vol 78 (12) ◽  
pp. 2170-2176 ◽  
Author(s):  
J. J. PADILLA-FRAUSTO ◽  
L. G. CEPEDA-MARQUEZ ◽  
L. M. SALGADO ◽  
M. H. ITURRIAGA ◽  
S. M. ARVIZU-MEDRANO

Some Leuconostoc spp. have the ability to produce slime and undesirable compounds in cooked sausage. The objectives of this research were to identify Leuconostoc sources in a Vienna-type sausage processing plant and to evaluate the genetic diversity of the isolated strains. Three hundred and two samples of sausage batter, sausages during processing, spoiled sausage, equipment surfaces, chilling brine, workers' gloves and aprons, and used casings were collected (March to November 2008 and February to April 2010) from a sausage processing plant. Lactic acid bacteria (LAB) were quantified, and Leuconostoc were detected using PCR. Strains were isolated and identified in Leuconostoc-positive samples. Leuconostoc strains were genotyped using randomly amplified polymorphic DNA and pulsed-field gel electrophoresis. LAB content of nonspoiled and spoiled sausage ranged from &lt;0.8 to 4.4 log CFU/g and from 4.9 to 8.3 log CFU/g, respectively. LAB levels on equipment surfaces ranged from &lt;1.3 to 4.8 log CFU/100 cm2. Leuconostoc was detected in 35% of the samples, and 88 Leuconostoc spp. strains were isolated and genotyped. The main Leuconostoc spp. isolated were L. mesenteroides (37 genotypes), L. fallax (29 genotypes), and L. lactis (6 genotypes). Some strains of Leuconostoc isolated from equipment surfaces and sausages showed the same genotype. One L. lactis genotype included strains isolated from spoiled sausages analyzed in April 2008 and March to April 2010. Equipment and conveyor belts constitute Leuconostoc contamination sources. Leuconostoc persistence in the sausage processing environment and in the final product suggests the existence of microbial reservoirs, possibly on equipment surfaces.


1999 ◽  
Vol 37 (6) ◽  
pp. 1927-1931 ◽  
Author(s):  
Samir P. Singh ◽  
Hugh Salamon ◽  
Carol J. Lahti ◽  
Mehran Farid-Moyer ◽  
Peter M. Small

Pulsed-field gel electrophoresis (PFGE) is a powerful molecular biology technique which has provided important insights into the epidemiology and population biology of many pathogens. However, few studies have used PFGE for the molecular epidemiology ofMycobacterium tuberculosis. A laboratory protocol was developed to determine the typeability, stability, and reproducibility of PFGE typing of M. tuberculosis. Formal data-analytical techniques were used to assess the genetic diversity elucidated by PFGE analyses using four separate restriction enzymes and by IS6110 RFLP analyses, as well as to assess the concordance among these typing methods. One hundred epidemiologically characterized clinical isolates of M. tuberculosis were genotyped with four different PFGE enzymes (AseI, DraI,SpeI, and XbaI), as well as by RFLP analysis with IS6110. Identical patterns were found among 34 isolates known to be genetically related, suggesting that the PFGE protocol is robust and reproducible. Among 66 isolates representing population-sampled cases, heterozygosity and information content dependency estimates indicate that all five genotyping systems capture quantitatively similar levels of genetic diversity. Nevertheless, comparisons between PFGE analyses and IS6110 typing reveals that PFGE provided more discrimination among isolates with fewer than five copies of IS6110 and less clustering in isolates with five or more copies. The comparisons confirm the hypothesis that the resolution of IS6110 RFLP genotyping is dependent upon the number of IS6110 elements in the genome of isolates. The general concordance among the results obtained with four independent enzymes suggests that M. tuberculosis is a clonal organism. The availability of a robust genotyping technique largely independent of repetitive elements has implications for the molecular epidemiology of M. tuberculosis.


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