scholarly journals Global population structure of Haemophilus influenzae serotype a (Hia) and emergence of invasive Hia disease: capsule switching or capsule replacement?

2021 ◽  
Author(s):  
Michelle Shuel ◽  
Natalie C Knox ◽  
Raymond S.W. Tsang
Keyword(s):  
Population Structure ◽  
Current Data ◽  
Division I ◽  
Human Respiratory Tract ◽  
Conjugate Vaccines ◽  
Recent Emergence ◽  
Burst Analysis ◽  
Division Ii ◽  
Global Population ◽  
Sequence Types

The population structure of Hia was examined by interrogation of the H. influenzae MLST website. There were 196 entries of Hia with 55 sequence types (STs) identified (as of September 3, 2020). BURST analysis clustered related STs into four complexes with ST-23, ST-4, ST-21 and ST-62 identified as their ancestral STs. The majority of Hia entries (73.4%) and STs (65.5%) were identified as clonal division I (ST-23 and the ST-4 complexes). Only 43 (21.9%) entries and 14 STs (25.5%) were identified as clonal division II (ST-62 and ST-21 complexes). Current data suggested most invasive Hia belonged to clonal division I and the ST-23 complex while most clonal division II Hia were respiratory isolates with the exception of ST-62 which was common among invasive Hia in the U.S. southwest. Comparison of the capsule bexABCD genes from clonal divisions I and II strains showed sequence diversity with variations following the pattern of clonal divisions. Evidence from the literature and the current study suggests recent emergence of invasive Hia might be related to capsule replacement subsequent to the implementation of the Hib conjugate vaccine and possibly exacerbated by other conjugate vaccines that may have altered the microbial flora of the human respiratory tract.

scholarly journals Combined Ribotyping and Random Multiprimer DNA Analysis To Probe the Population Structure of Listeria monocytogenes

2002 ◽  
Vol 68 (6) ◽  
pp. 2849-2857 ◽  
Author(s):  
L. Mereghetti ◽  
P. Lanotte ◽  
V. Savoye-Marczuk ◽  
N. Marquet-Van Der Mee ◽  
A. Audurier ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Listeria Monocytogenes ◽  
Genetic Structure ◽  
Dna Analysis ◽  
Division I ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
Clustering Methods ◽  
Division Ii

ABSTRACT To improve our understanding of the genetic links between strains originating from food and strains responsible for human diseases, we studied the genetic diversity and population structure of 130 epidemiologically unrelated Listeria monocytogenes strains. Strains were isolated from different sources and ecosystems in which the bacterium is commonly found. We used rRNA gene restriction fragment length polymorphism analysis with two endonucleases and random multiprimer DNA analysis with seven oligonucleotide primers to study multiple genetic features of each strain. We used three clustering methods to identify genetic links between individual strains and to determine the precise genetic structure of the population. The combined results confirmed that L. monocytogenes strains can be divided into two major phylogenetic divisions. The method used allowed us to demonstrate that the genetic structure and diversity of the two phylogenetic divisions differ. Division I is the most homogeneous and can easily be divided into subgroups with dissimilarity distances of less than 0.30. Each of these subgroups mainly, or exclusively, contains a single serotype (1/2b, 4b, 3b, or 4a). The serotype 4a lineage appears to form a branch that is highly divergent from the phylogenetic group containing serotypes 1/2b, 4b, and 3b. Division II contains strains of serotypes 1/2a, 1/2c, and 3a. It exhibits more genetic diversity with no peculiar clustering. The fact that division II is more heterogeneous than division I suggests that division II evolved from a common ancestor earlier than division I. A significant association was found between division I and human strains, suggesting that strains from division I are better adapted to human hosts.

scholarly journals Impact of Various Collegiate Settings on Athletic Trainers’ Definition of Professional Commitment

2014 ◽  
Author(s):  
Stephine Mazerolle ◽  
Christianne Eason
Keyword(s):  
Athletic Training ◽  
Student Athletes ◽  
Quality Care ◽  
Division I ◽  
Professional Commitment ◽  
Full Time ◽  
Division Iii ◽  
Division Ii ◽  
Definition Of ◽  
The Impact

Purpose: Professional commitment is an individualized concept that combines commitment to a profession and the organization of employment. Currently there is no distinct definition of professional commitment within the context of athletic training. Therefore, the purpose of our study was to evaluate the impact of collegiate divisional setting on the definition of professional commitment. Methods: Online asynchronous interviews. Inclusion criteria consisted of full-time employment in the collegiate setting with at least 1 year of experience beyond a graduate assistantship. Thirty-three BOC certified ATs employed in the collegiate setting (Division I =11, Division II = 9, Division III = 13) volunteered with an average of 10 ± 8 years of clinical experience. Data saturation guided the total number of participants. Participants journaled their thoughts and experiences via QuestionPro™. Multiple analyst triangulation and peer review were included and data was analyzed utilizing general inductive analysis. Results: The importance of current practices emerged across all three settings. ATs in the Division I setting viewed commitment as advocating for their student athletes, providing the best care possible, and mentoring them as young adults. In the Division II setting, ATs were focused on life-long learning as a reflection of commitment. This was often accomplished by attending seminars, completing CEUs, and continually adding to their skill set in order to provide the best care for their student athletes. Division III focused their definition on being a multifaceted health care provider. Exceeding expectations and being a dedicated professional was an aspect of professional commitment. Conclusions: It is important to understand what keeps ATs motivated in the profession in order to enhance retention strategies. Overall, ATs’ professional commitment is derived from providing quality care to student-athletes, continuously advancing education within the profession, and being a multifaceted healthcare provider.

scholarly journals Differences in Neisseria gonorrhoeae population structure and antimicrobial resistance pattern between men who have sex with men and heterosexuals

2016 ◽  
Vol 145 (2) ◽  
pp. 379-385 ◽  
Author(s):  
J. SERRA-PLADEVALL ◽  
M. J. BARBERÁ ◽  
A. E. CALLARISA ◽  
R. BARTOLOMÉ-COMAS ◽  
A. ANDREU
Keyword(s):  
Population Structure ◽  
Antimicrobial Resistance ◽  
Neisseria Gonorrhoeae ◽  
Antimicrobial Susceptibility ◽  
Sexual Practices ◽  
Resistance Pattern ◽  
High Prevalence ◽  
Sex With Men ◽  
Resistance Rates ◽  
Sequence Types

SUMMARYThis study compared the antimicrobial susceptibility and genotypes of strains of Neisseria gonorrhoeae isolated from men who have sex with men (MSM) and from heterosexuals. One hundred and eleven strains were characterized from 107 patients, comprising 57 strains from 54 heterosexuals and 54 strains from 53 MSM. Antimicrobial resistance rates were higher in strains from heterosexual patients, with resistance to cefixime (P = 0·0159) and ciprofloxacin (P = 0·002) being significantly higher. Typing by N. gonorrhoeae multi-antigen sequence typing (NG-MAST) showed that the most prevalent sequence types (ST) and genogroups (G) respectively were ST2400, ST2992, and ST5793, and G1407, G2992, and G2400. A statistically significant association was observed for MSM and genogroups G2400 (P = 0·0005) and G2992 (P = 0·0488), and G1407 with heterosexuals (P = 0·0002). We conclude that in our region distinct populations of gonococci are circulating among subjects with different sexual practices, with their corresponding transmission patterns. Furthermore, the high prevalence of genotype G2400 in MSM, has not to our knowledge been previously described.

scholarly journals Genomic Characteristics of Invasive Streptococcus pneumoniae Serotype 1 in New Caledonia Prior to the Introduction of PCV13

2020 ◽  
Vol 14 ◽  
pp. 117793222096210 ◽  
Author(s):  
Mariem Hanachi ◽  
Anmol Kiran ◽  
Jennifer Cornick ◽  
Emna Harigua-Souiai ◽  
Dean Everett ◽  
...  
Keyword(s):  
Population Structure ◽  
Streptococcus Pneumoniae ◽  
Virulence Genes ◽  
New Caledonia ◽  
Disease Outbreaks ◽  
Genomic Diversity ◽  
Whole Genome Sequence ◽  
Serotype 1 ◽  
The Impact ◽  
Sequence Types

Streptococcus pneumoniae serotype 1 is a common cause of global invasive pneumococcal disease. In New Caledonia, serotype 1 is the most prevalent serotype and led to two major outbreaks reported in the 2000s. The pneumococcal conjugate vaccine 13 (PCV13) was introduced into the vaccination routine, intending to prevent the expansion of serotype 1 in New Caledonia. Aiming to provide a baseline for monitoring the post-PCV13 changes, we performed a whole-genome sequence analysis on 67 serotype 1 isolates collected prior to the PCV13 introduction. To highlight the S. pneumoniae serotype 1 population structure, we performed a multilocus sequence typing (MLST) analysis revealing that NC serotype 1 consisted of 2 sequence types: ST3717 and the highly dominant ST306. Both sequence types harbored the same resistance genes to beta-lactams, macrolide, streptogramin B, fluoroquinolone, and lincosamide antibiotics. We have also identified 36 virulence genes that were ubiquitous to all the isolates. Among these virulence genes, the pneumolysin sequence presented an allelic profile associated with disease outbreaks and reduced hemolytic activity. Moreover, recombination hotspots were identified in 4 virulence genes and more notably in the cps locus ( cps2L), potentially leading to capsular switching, a major mechanism of the emergence of nonvaccine types. In summary, this study represents the first overview of the genomic characteristics of S. pneumoniae serotype 1 in New Caledonia prior to the introduction of PCV13. This preliminary description represents a baseline to assess the impact of PCV13 on serotype 1 population structure and genomic diversity.

scholarly journals Population Structure and Antimicrobial Resistance of Canine UropathogenicEscherichia coli

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Tessa E. LeCuyer ◽  
Barbara A. Byrne ◽  
Joshua B. Daniels ◽  
Dubraska V. Diaz-Campos ◽  
G. Kenitra Hammac ◽  
...  
Keyword(s):  
Population Structure ◽  
Antimicrobial Resistance ◽  
Companion Animals ◽  
Sequence Type ◽  
Content Type ◽  
E Coli ◽  
Extraintestinal Disease ◽  
Human Infections ◽  
Sequence Types

ABSTRACTEscherichia coliis the most common cause of human and canine urinary tract infection (UTI). Clonal groups, often with high levels of antimicrobial resistance, are a major component of theE. colipopulation that causes human UTI. While little is known about the population structure ofE. colithat causes UTI in dogs, there is evidence that dogs and humans can share fecal strains ofE. coliand that human-associated strains can cause disease in dogs. In order to better characterize theE. colistrains that cause canine UTI, we analyzed 295E. coliisolates obtained from canine urine samples from five veterinary diagnostic laboratories and analyzed their multilocus sequence types, phenotypic and genotypic antimicrobial resistance profiles, and virulence-associated gene repertoires. Sequence type 372 (ST372), an infrequent human pathogen, was the predominant sequence type in dogs at all locations. Extended-spectrum β-lactamase-producing isolates withblaCTX-Mgenes were uncommon in canine isolates but when present were often associated with sequence types that have been described in human infections. This provides support for occasional cross-host-species sharing of strains that cause extraintestinal disease and highlights the importance of understanding the role of companion animals in the overall transmission patterns of extraintestinal pathogenicE. coli.

scholarly journals Population structure of drug-resistant Mycobacterium tuberculosis in Central Asia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Anna Engström ◽  
Uladzimir Antonenka ◽  
Abdylat Kadyrov ◽  
Gulmira Kalmambetova ◽  
Katharina Kranzer ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Population Structure ◽  
Central Asia ◽  
Tandem Repeats ◽  
Relative Size ◽  
Multidrug Resistant ◽  
Variable Number ◽  
Health Concern ◽  
Drug Resistant ◽  
Recent Emergence

Abstract Background Drug-resistant tuberculosis (TB) is a major public health concern threathing the success of TB control efforts, and this is particularily problematic in Central Asia. Here, we present the first analysis of the population structure of Mycobacterium tuberculosis complex isolates in the Central Asian republics Uzbekistan, Tajikistan, and Kyrgyzstan. Methods The study set consisted of 607 isolates with 235 from Uzbekistan, 206 from Tajikistan, and 166 from Kyrgyzstan. 24-loci MIRU-VNTR (Mycobacterial Interspersed Repetitive Units - Variable Number of Tandem Repeats) typing and spoligotyping were combined for genotyping. In addition, phenotypic drug suceptibility was performed. Results The population structure mainly comprises strains of the Beijing lineage (411/607). 349 of the 411 Beijing isolates formed clusters, compared to only 33 of the 196 isolates from other clades. Beijing 94–32 (n = 145) and 100–32 (n = 70) formed the largest clusters. Beijing isolates were more frequently multidrug-resistant, pre-extensively resistant (pre-XDR)- or XDR-TB than other genotypes. Conclusions Beijing clusters 94–32 and 100–32 are the dominant MTB genotypes in Central Asia. The relative size of 100–32 compared to previous studies in Kazakhstan and its unequal geographic distribution support the hypothesis of its more recent emergence in Central Asia. The data also demonstrate that clonal spread of resistant TB strains, particularly of the Beijing lineage, is a root of the so far uncontroled MDR-TB epidemic in Central Asia.

Population structure of group B streptococcus from a low-incidence region for invasive neonatal disease

Microbiology ◽  
2005 ◽  
Vol 151 (6) ◽  
pp. 1875-1881 ◽  
Author(s):  
Naiel Bisharat ◽  
Nicola Jones ◽  
Dror Marchaim ◽  
Colin Block ◽  
Rosalind M. Harding ◽  
...  
Keyword(s):  
Population Structure ◽  
Disease Incidence ◽  
Group B Streptococcus ◽  
Invasive Disease ◽  
Multilocus Genotype ◽  
Neonatal Disease ◽  
Strain Collection ◽  
Low Incidence ◽  
Group B ◽  
Sequence Types

The population structure of group B streptococcus (GBS) from a low-incidence region for invasive neonatal disease (Israel) was investigated using multilocus genotype data. The strain collection consisted of isolates from maternal carriage (n=104) and invasive neonatal disease (n=50), resolving into 46 sequence types. The most prevalent sequence types were ST-1 (17·5 %), ST-19 (10·4 %), ST-17 (9·7 %), ST-22 (8·4 %) and ST-23 (6·5 %). Serotype III was the most common, accounting for 29·2 % of the isolates. None of the serotypes was significantly associated with invasive neonatal disease. burst analysis resolved the 46 sequence types into seven lineages (clonal complexes), from which only lineage ST-17, expressing serotype III only, was significantly associated with invasive neonatal disease. Lineage ST-22 expressed mainly serotype II, and was significantly associated with carriage. The distribution of the various sequence types and lineages, and the association of lineage ST-17 with invasive disease, are consistent with the results of analyses from a global GBS isolate collection. These findings could imply that the global variation in disease incidence is independent of the circulating GBS populations, and may be more affected by other risk factors for invasive GBS disease, or by different prevention strategies.

scholarly journals Global Population Structure and Natural History of the Green Turtle (Chelonia mydas) in Terms of Matriarchal Phylogeny

Evolution ◽  
1992 ◽  
Vol 46 (4) ◽  
pp. 865 ◽  
Author(s):  
Brian W. Bowen ◽  
Anne B. Meylan ◽  
J. Perran Ross ◽  
Colin J. Limpus ◽  
George H. Balazs ◽  
...  
Keyword(s):  
Population Structure ◽  
Natural History ◽  
Green Turtle ◽  
Chelonia Mydas ◽  
History Of ◽  
Global Population

scholarly journals Clonal Population Structure and Specific Genotypes of Multidrug-Resistant Campylobacter coli from Turkeys

2007 ◽  
Vol 73 (7) ◽  
pp. 2156-2164 ◽  
Author(s):  
C. B. D'lima ◽  
W. G. Miller ◽  
R. E. Mandrell ◽  
S. L. Wright ◽  
R. M. Siletzky ◽  
...  
Keyword(s):  
North Carolina ◽  
Population Structure ◽  
Multidrug Resistant ◽  
Source Tracking ◽  
Campylobacter Coli ◽  
Clonal Population ◽  
Antimicrobial Resistance Profile ◽  
Clonal Population Structure ◽  
Commercial Turkey ◽  
Sequence Types

ABSTRACT Commercial turkey flocks in North Carolina have been found to be colonized frequently with Campylobacter coli strains that are resistant to several antimicrobials (tetracycline, streptomycin, erythromycin, kanamycin, and ciprofloxacin/nalidixic acid). Such strains have been designated multidrug resistant (MDR). However, the population structure of MDR C. coli from turkeys remains poorly characterized. In this study, an analysis of multilocus sequence typing (MLST)-based sequence types (STs) of 59 MDR strains from turkeys revealed that the majority of these strains corresponded to one of 14 different STs, with three STs accounting for 41 (69%) of the strains. The major STs were turkey specific, and most (87%) of the strains with these STs were resistant to the entire panel of antibiotics mentioned above. Some (13%) of the strains with these STs were susceptible to just one or two of the antibiotics in this panel. Further subtyping using fla typing and pulsed-field gel electrophoresis with SmaI and KpnI revealed that the major MDR STs corresponded to strains of related but distinct subtypes, providing evidence for genomic diversification within these STs. These findings suggest that MDR strains of C. coli from turkeys have a clonal population structure characterized by the presence of a relatively small number of clonal groups that appear to be disseminated in the turkey production system. In addition, the observed correlation between STs and the MDR profiles of the microbes indicates that MLST-based typing holds potential for source-tracking applications specific to the animal source (turkeys) and the antimicrobial resistance profile (MDR status) of C. coli.

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