scholarly journals Genetic diversity of Streptococcus suis clinical isolates from pigs and humans in Italy (2003-2007)

2009 ◽  
Vol 14 (33) ◽  
Author(s):  
M S Princivalli ◽  
C Palmieri ◽  
G Magi ◽  
C Vignaroli ◽  
A Manzin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Antibiotic Resistance Genes ◽  
Streptococcus Suis ◽  
Invasive Disease ◽  
Clinical Isolates ◽  
High Genetic Diversity ◽  
Pork Products ◽  
Genotypic Analysis ◽  
Common Clinical Presentation ◽  
Industrialised Countries

Streptococcus suis, a major porcine pathogen, is emerging as a zoonotic agent capable of causing severe invasive disease in humans exposed to pigs or pork products. S. suis infection is rare in industrialised countries and usually arises as sporadic cases, with meningitis the most common clinical presentation in humans. Recent reports of two cases of meningitis in Sardinia and north-eastern Italy prompted this first characterisation of Italian S. suis isolates. Fifty-nine S. suis strains, the two recent human strains and 57 swine clinical isolates collected between 2003 and 2007 from different Italian herds and regions, were tested for antimicrobial susceptibility, PCR-screened for virulence and antibiotic resistance genes, and subjected to molecular typing. Phenotypic and genotypic analysis demonstrated an overall high genetic diversity among isolates, the majority of which were resistant to macrolides (78%) and tetracyclines (90%). The erm(B), tet(O), mosaic tet(O/W/32/O), tet(W), and tet(M) genes were detected. The tet(O/W/32/O) gene, the most frequent tet gene after tet(O), had never been described in the genus Streptococcus before. In addition, a virulent cps2, erm(B) tet(O) clone, belonging to sequence type 1 (ST1) of the ST1 complex, was found to be prevalent and persistent in Italian swine herds. Finally, the two human isolates (both ST1) carrying cps2, erm(B) and tet(W) were seen to be closely related to each other.

scholarly journals Diversity of cwp loci in clinical isolates of Clostridium difficile

2013 ◽  
Vol 62 (9) ◽  
pp. 1444-1452 ◽  
Author(s):  
Manuele Biazzo ◽  
Rossella Cioncada ◽  
Luigi Fiaschi ◽  
Vittorio Tedde ◽  
Patrizia Spigaglia ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Clostridium Difficile ◽  
Total Cell ◽  
The Other ◽  
Clinical Isolates ◽  
Cell Wall Proteins ◽  
High Genetic Diversity ◽  
Cell Extracts ◽  
Number Of Genes ◽  
Genes Encoding

An increased incidence of Clostridium difficile infection (CDI) is associated with the emergence of epidemic strains characterized by high genetic diversity. Among the factors that may have a role in CDI is a family of 29 paralogues, the cell-wall proteins (CWPs), which compose the outer layer of the bacterial cell and are likely to be involved in colonization. Previous studies have shown that 12 of the 29 cwp genes are clustered in the same region, named after slpA (cwp1), the slpA locus, whereas the remaining 17 paralogues are distributed throughout the genome. The variability of 14 of these 17 cwp paralogues was determined in 40 C. difficile clinical isolates belonging to six of the currently prevailing PCR ribotypes. Based on sequence conservation, these cwp genes were divided into two groups, one comprising nine cwp loci having highly conserved sequences in all isolates, and the other five loci showing low genetic conservation among isolates of the same PCR ribotype, as well as between different PCR ribotypes. Three conserved CWPs, Cwp16, Cwp18 and Cwp25, and two variable ones, Cwp26 and Cwp27, were characterized further by Western blot analysis of total cell extracts or surface-layer preparations of the C. difficile clinical isolates. Expression of genetically invariable CWPs was well conserved in all isolates, whilst genetically variable CWPs were not always expressed at comparable levels, even in strains containing identical sequences but belonging to different PCR ribotypes. This is the first report on the distribution and variability of a number of genes encoding CWPs in C. difficile.

scholarly journals Genetic Diversity and Population Structure of Vibrio parahaemolyticus Isolated From Clinical and Food Sources

2021 ◽  
Vol 12 ◽  
Author(s):  
Min He ◽  
Tao Lei ◽  
Fufeng Jiang ◽  
Jumei Zhang ◽  
Haiyan Zeng ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Vibrio Parahaemolyticus ◽  
Large Scale ◽  
Foodborne Pathogen ◽  
Guangdong Province ◽  
Housekeeping Genes ◽  
Clinical Isolates ◽  
Food Sources ◽  
Clinical Samples ◽  
High Genetic Diversity

Vibrio parahaemolyticus is a common foodborne pathogen that causes gastroenteritis worldwide. Determining its prevalence and genetic diversity will minimize the risk of infection and the associated economic burden. Multilocus sequence typing (MLST) is an important tool for molecular epidemiology and population genetic studies of bacteria. Here, we analyzed the genetic and evolutionary relationships of 162 V. parahaemolyticus strains isolated in the Guangdong Province, China, using MLST. In the study, 120 strains were isolated from food samples, and 42 strains were isolated from clinical samples. All strains were categorized into 100 sequence types (STs), of which 58 were novel (48 from the food isolates and 10 from the clinical isolates). ST415 was the most prevalent ST among the food isolates, while ST3 was the most prevalent ST among the clinical isolates. Further, 12 clonal complexes, 14 doublets, and 73 singletons were identified in all ST clusters, indicating high genetic diversity of the analyzed strains. At the concatenated sequence level, non-synonymous sites in both, food and clinical isolates, were associated with purifying selection. Of note, the dN/dS ration was greater than 1 for some housekeeping genes in all isolates. This is the first time that some loci under positive selection were identified. These observations confirm frequent recombination events in V. parahaemolyticus. Recombination was much more important than mutation for genetic heterogeneity of the food isolates, but the probabilities of recombination and mutations were almost equal for the clinical isolates. Based on the phylogenetic analysis, the clinical isolates were concentrated in the maximum-likelihood tree, while the food isolates were heterogeneously distributed. In conclusion, the food and clinical isolates of V. parahaemolyticus from the Guangdong Province are similar, but show different evolutionary trends. This may help prevent large-scale spread of highly virulent strains and provides a genetic basis for the discovery of microevolutionary relationships in V. parahaemolyticus populations.

Prevalence and Genotyping of Commensal Neisseria with Reduced Susceptibility to Penicillin

2015 ◽  
Vol 25 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Arij Mechergui ◽  
Wafa Achour ◽  
Assia Ben Hassen
Keyword(s):  
Genetic Diversity ◽  
Elevated Level ◽  
Clinical Isolates ◽  
Penicillin Resistance ◽  
High Genetic Diversity ◽  
Clonal Relationship ◽  
Neutropenic Patients

We analyzed 85 <i>Neisseria </i>spp. strains collected by swabbing from neutropenic patients to determine the prevalence of reduced susceptibility to penicillin and to ascertain the clonal relationship between these strains. High genetic diversity and an elevated level of penicillin resistance were found among commensal <i>Neisseria </i>clinical isolates.

scholarly journals Non-serotype 2 isolates from healthy pigs are a potential zoonotic reservoir of Streptococcus suis genetic diversity and antimicrobial resistance

2021 ◽  
Author(s):  
Nattinee Kittiwan ◽  
Jessica K Calland ◽  
Evangelos Mourkas ◽  
Matthew D Hitchings ◽  
Susan Murray ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Close Contact ◽  
Streptococcus Suis ◽  
Invasive Disease ◽  
Economic Losses ◽  
Swine Industry ◽  
Integrative And Conjugative Elements ◽  
Antimicrobial Resistance Genes

Streptococcus suis is a leading cause of bacterial meningitis in SE Asia, with frequent zoonotic transfer to humans associated with close contact with pigs. A small number of invasive lineages are responsible for endemic infection in the swine industry causing considerable global economic losses. A lack of surveillance and a rising trend in clinical treatment failure has raised concerns of growing antimicrobial resistance (AMR) among invasive S. suis. The source-sink dynamics between healthy and disease isolates is poorly understood and, in this study, we sample and sequence a collection of isolates predominantly from healthy pigs in Chiang Mai province, Northern Thailand. Pangenome comparisons with a selection of invasive serotype 2 isolates identified increased genetic diversity and more frequent AMR carriage in isolates from healthy pigs. Multiple antimicrobial resistance genes were identified conferring resistance to aminoglycosides, lincosamides, tetracycline and macrolides. All isolates were non-susceptinle to three or more different antimicrobial classes, and 75% of non-serotype 2 isolates were non-susceptible to 6 or more classes (compared to 37.5% of serotype 2 isolates). Antimicrobial resistance genes were found on integrative and conjugative elements (ICE) previously observed in other species, suggesting mobile gene pool which can be accessed by invasive disease isolates.

scholarly journals Genetic diversity and molecular analysis of metallo beta lactamases among imipenem resistant clinical isolates of Pseudomonas aeruginosa from Peshawar, Pakistan

2021 ◽  
Vol 37 (7) ◽  
Author(s):  
Amjad Ali ◽  
Kafeel Ahmad ◽  
Shaista Rahat ◽  
Israr Ahmad
Keyword(s):  
Genetic Diversity ◽  
Pseudomonas Aeruginosa ◽  
Molecular Analysis ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
High Genetic Diversity ◽  
Beta Lactamases ◽  
Creative Commons ◽  
High Prevalence ◽  
Control And Prevention

Objectives: Pseudomonas aeruginosa is an opportunistic pathogen with remarkable adaptation ability to thrive in diverse environmental conditions. This study aimed at phenotypic and molecular analysis of metallo beta lactamases (blaIMP, blaVIM, blaNDM-1 and blaSPM-1) and genetic diversity analysis among imipenem resistant clinical isolates of Pseudomonas aeruginosa. Methods: This study was conducted from May 2017 to June 2018. The study included 187 Pseudomonas aeruginosa isolates collected from different clinical specimens from Peshawar, Pakistan. The isolates were analyzed for resistance to imipenem. Combined disc test (CDT) was then performed for phenotypic detection of metallo beta lactamases among imipenem resistant isolates of Pseudomonas aeruginosa. Molecular detection of metallo beta lactamases genes i.e. blaIMP, blaVIM, blaNDM-1 and blaSPM-1 was analyzed through polymerase chain reaction. Genetic diversity was determined through RAPD-PCR. Results: MBL production was observed in 76% (n=19) isolates. The occurrence of MBL genes blaIMP, blaNDM-1 and blaVIM was 68% (n=17), 48% (n=12), and 4% (n=1) respectively. The blaSPM-1 gene was not detected. High genetic diversity was observed in current study. Out of 182 isolates 171 isolates showed different RAPD profiles (93.95% polymorphism); 160 were unique RAPD strains and based on similarity coefficient ≥ 80%, 22 isolates were clustered into 11 distinct clones. Conclusion: A high prevalence of blaIMP and blaNDM-1 among imipenem resistant isolates of Pseudomonas aeruginosa is alarming that calls for proper control and prevention strategies. RAPD technique was found to be a good genotyping technique when limited resources are available. doi: https://doi.org/10.12669/pjms.37.7.4303 How to cite this:Ali A, Ahmad K, Rahat S, Ahmad I. Genetic diversity and molecular analysis of metallo beta lactamases among imipenem resistant clinical isolates of Pseudomonas aeruginosa from Peshawar, Pakistan. Pak J Med Sci. 2021;37(7):---------.  doi: https://doi.org/10.12669/pjms.37.7.4303 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals Analysis of 44 Vibrio anguillarum genomes reveals high genetic diversity

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10451
Author(s):  
Mie Johanne Hansen ◽  
Egle Kudirkiene ◽  
Inger Dalsgaard
Keyword(s):  
Genetic Diversity ◽  
Rainbow Trout ◽  
De Novo ◽  
Vibrio Anguillarum ◽  
Antibiotic Resistance Genes ◽  
Economic Losses ◽  
Nucleotide Polymorphisms ◽  
High Genetic Diversity ◽  
Pan Genome ◽  
Almost All

Vibriosis, a hemorrhagic septicemic disease caused by the bacterium Vibrio anguillarum, is an important bacterial infection in Danish sea-reared rainbow trout. Despite of vaccination, outbreaks still occur, likely because the vaccine is based on V. anguillarum strains from abroad/other hosts than rainbow trout. Information about the genetic diversity of V. anguillarum specifically in Danish rainbow trout, is required to investigate this claim. Consequently, the aim of the present investigation was to sequence and to characterize a collection of 44 V. anguillarum strains obtained primarily from vibriosis outbreaks in Danish rainbow trout. The strains were sequenced, de novo assembled, and the genomes examined for the presence of plasmids, virulence, and acquired antibiotic resistance genes. To investigate the phylogeny, single nucleotide polymorphisms were identified, and the pan-genome was calculated. All strains carried tet(34) encoding tetracycline resistance, and 36 strains also contained qnrVC6 for increased fluoroquinolone/quinolone resistance. But interestingly, all strains were phenotypic sensitive to both oxytetracycline and oxolinic acid. Almost all serotype O1 strains contained a pJM1-like plasmid and nine serotype O2A strains carried the plasmid p15. The distribution of virulence genes was rather similar across the strains, although evident variance among serotypes was observed. Most significant, almost all serotype O2 and O3 strains, as well as the serotype O1 strain without a pJM1-like plasmid, carried genes encoding piscibactin biosynthesis. Hence supporting the hypothesis, that piscibactin plays a crucial role in virulence for pathogenic strains lacking the anguibactin system. The phylogenetic analysis and pan-genome calculations revealed great diversity within V. anguillarum. Serotype O1 strains were in general very similar, whereas considerable variation was found among serotype O2A strains. The great diversity within the V. anguillarum serotype O2A genomes is most likely the reason why vaccines provide good protection from some strains, but not from others. Hopefully, the new genomic data and knowledge provided in this study might help develop an optimized vaccine against V. anguillarum in the future to reduce the use of antibiotics, minimize economic losses and improve the welfare of the fish.

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