scholarly journals Colonization of healthy children by Moraxella catarrhalis is characterized by genotype heterogeneity, virulence gene diversity and co-colonization with Haemophilus influenzae

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 169-178 ◽  
Author(s):  
Suzanne J. C. Verhaegh ◽  
Martine L. Snippe ◽  
Foster Levy ◽  
Henri A. Verbrugh ◽  
Vincent W. V. Jaddoe ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Moraxella Catarrhalis ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Bacterial Species ◽  
Genotypic Variation ◽  
Virulence Gene ◽  
Single Species ◽  
Healthy Children ◽  
Genotypic Analysis

The colonization dynamics of Moraxella catarrhalis were studied in a population comprising 1079 healthy children living in Rotterdam, The Netherlands (the Generation R Focus cohort). A total of 2751 nasal swabs were obtained during four clinic visits timed to take place at 1.5, 6, 14 and 24 months of age, yielding a total of 709 M. catarrhalis and 621 Haemophilus influenzae isolates. Between January 2004 and December 2006, approximate but regular 6-monthly cycles of colonization were observed, with peak colonization incidences occurring in the autumn/winter for M. catarrhalis, and winter/spring for H. influenzae. Co-colonization was significantly more likely than single-species colonization with either M. catarrhalis or H. influenzae, with genotypic analysis revealing no clonality for co-colonizing or single colonizers of either bacterial species. This finding is especially relevant considering the recent discovery of the importance of H. influenzae–M. catarrhalis quorum sensing in biofilm formation and host clearance. Bacterial genotype heterogeneity was maintained over the 3-year period of the study, even within this relatively localized geographical region, and there was no association of genotypes with either season or year of isolation. Furthermore, chronological and genotypic diversity in three immunologically important M. catarrhalis virulence genes (uspA1, uspA2 and hag/mid) was also observed. This study indicates that genotypic variation is a key factor contributing to the success of M. catarrhalis colonization of healthy children in the first years of life. Furthermore, variation in immunologically relevant virulence genes within colonizing populations, and even within genotypically identical M. catarrhalis isolates, may be a result of immune evasion by this pathogen. Finally, the factors facilitating M. catarrhalis and H. influenzae co-colonization need to be further investigated.

scholarly journals Increased recovery of Moraxella catarrhalis and Haemophilus influenzae in association with group A β-haemolytic streptococci in healthy children and those with pharyngo-tonsillitis

2006 ◽  
Vol 55 (8) ◽  
pp. 989-992 ◽  
Author(s):  
Itzhak Brook ◽  
Alan E. Gober
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Haemophilus Influenzae ◽  
Moraxella Catarrhalis ◽  
Inflammatory Process ◽  
Bacterial Species ◽  
Healthy Children ◽  
Staph Aureus ◽  
Penicillin Therapy ◽  
Group A

The inflamed tonsils harbour numerous types of bacteria, alone or in combination with group A β-haemolytic streptococci (GABHS). The cohabitation of the tonsils by GABHS and certain other bacterial species may contribute to the inflammatory process and the failure of penicillin therapy. This study evaluated the recovery of Moraxella catarrhalis, Haemophilus influenzae, Staphylococcus aureus and Streptococcus pneumoniae in association with GABHS in healthy children and those with acute pharyngo-tonsillitis (APT). Pharyngo-tonsillar cultures were obtained from 548 children with APT and 866 healthy children. GABHS was recovered from 112 (20.4 %) children with APT. Of the 114 H. influenzae isolates, 32 were recovered in association with GABHS (29 % of all patients who had GABHS) and 82 were isolated without GABHS (19 %) (P=0.0267). Of the 69 M. catarrhalis isolates, 25 were recovered in association with GABHS (22 % of all patients who had GABHS) and 44 were isolated without GABHS (10 %) (P=0.0012). In contrast, there was no association between the isolation of GABHS and the recovery of Staph. aureus or Strep. pneumoniae. GABHS was recovered from 104 (12 %) healthy children. Of the 69 M. catarrhalis isolates, 24 were recovered in association with GABHS (23 % of all patients who had GABHS) and 80 were isolated without GABHS (10 %) (P=0.006). There was no association between the isolation of GABHS and the recovery of H. influenzae, Staph. aureus or Strep. pneumoniae. This study demonstrates an association between the recovery of GABHS and H. influenzae and M. catarrhalis from pharyngo-tonsillar cultures of patients with APT and M. catarrhalis from pharyngo-tonsillar cultures of healthy children.

scholarly journals Characteristics of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus isolated from the nasopharynx of healthy children attending day-care centres in the Czech Republic

2006 ◽  
Vol 134 (6) ◽  
pp. 1179-1187 ◽  
Author(s):  
H. ŽEMLIČKOVÁ ◽  
P. URBÁšKOVÁ ◽  
V. ADÁMKOVÁ ◽  
J. MOTLOVÁ ◽  
V. LEBEDOVÁ ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Haemophilus Influenzae ◽  
Moraxella Catarrhalis ◽  
Day Care ◽  
Respiratory Pathogens ◽  
Healthy Children ◽  
Older Children ◽  
Age Related ◽  
Day Care Centres

Nasopharyngeal carriage of potential pathogens was studied in 425 healthy 3- to 6-year-old children attending 16 day-care centres (DCCs) in nine Czech cities during the winter 2004–2005. The overall carriage of pathogens was 62·8% (Streptococcus pneumoniae, 38·1%; Haemophilus influenzae, 24·9%; Moraxella catarrhalis, 22·1%; Staphylococcus aureus, 16%). An age-related downward trend was observed for colonization with respiratory pathogens in contrast to Staph. aureus whose carriage was significantly higher among older children. The following serotypes of colonizing S. pneumoniae were the most predominant: 23F (20·6%), 6A (15·1%), 6B (12·7%), 18C (7·8%), 15B and 19F (6% each). The majority (94·3%) of H. influenzae isolates were non-typable; among capsulated isolates, serotype b was not found. Decreased susceptibility to penicillin was determined in 3% of pneumococci; 4·6% of H. influenzae strains and 85·1% of M. catarrhalis strains produced β-lactamase. As for non-β-lactam antibiotics, pneumococci resistant to trimethoprim–sulphamethoxazole were the most common (15·7%) among the attendees.

scholarly journals Sputum sample positivity for Haemophilus influenzae or Moraxella catarrhalis in acute exacerbations of chronic obstructive pulmonary disease: evaluation of association with positivity at earlier stable disease timepoints

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lucio Malvisi ◽  
◽  
Laura Taddei ◽  
Aparna Yarraguntla ◽  
Tom M. A. Wilkinson ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Haemophilus Influenzae ◽  
Pulmonary Disease ◽  
Moraxella Catarrhalis ◽  
Bacterial Species ◽  
Sputum Sample ◽  
Stable State ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Post Hoc

Abstract Background Infection with Haemophilus influenzae (Hi) or Moraxella catarrhalis (Mcat) is a risk factor for exacerbation in chronic obstructive pulmonary disease (COPD). The ability to predict Hi- or Mcat-associated exacerbations may be useful for interventions developed to reduce exacerbation frequency. Methods In a COPD observational study, sputum samples were collected at monthly stable-state visits and at exacerbation during two years of follow-up. Bacterial species (Hi, Mcat) were identified by culture and quantitative PCR assay. Post-hoc analyses were conducted to assess: (1) first Hi- or Mcat-positive exacerbations given presence or absence of Hi or Mcat at the screening visit (stable-state timepoint); (2) first Hi- or Mcat-positive exacerbations given presence or absence of Hi or Mcat at stable timepoints within previous 90 days; (3) second Hi- or Mcat-positive exacerbations given presence or absence of Hi or Mcat at stable timepoints within previous 90 days. Percentages and risk ratios (RRs) with 95% confidence intervals were calculated. Results PCR results for analyses 1, 2 and 3 (samples from 84, 88 and 83 subjects, respectively) showed that the risk of an Hi- or Mcat-positive exacerbation is significantly higher if sputum sample was Hi- or Mcat-positive than if Hi- or Mcat-negative at previous stable timepoints (apart from Mcat in analysis 3); RRs ranged from 2.1 to 3.2 for Hi and 1.9 to 2.6 for Mcat.For all analyses, the percentage of Hi- or Mcat-positive exacerbations given previous Hi- or Mcat-positive stable timepoints was higher than the percentage of Hi- or Mcat-positive exacerbations if Hi- or Mcat-negative at previous stable timepoints. Percentage of Hi- or Mcat-positive exacerbations given previous Hi- or Mcat-negative stable timepoints was 26.3%–37.0% for Hi and 17.6%–19.7% for Mcat. Conclusions Presence of Hi or Mcat at a stable timepoint was associated with a higher risk of a subsequent Hi- or Mcat-associated exacerbation compared with earlier absence. However, a large percentage of Hi- or Mcat-associated exacerbations was not associated with Hi/Mcat detection at an earlier timepoint. This suggests that administration of an intervention to reduce these exacerbations should be independent of bacterial presence at baseline. Trial Registrationhttps://clinicaltrials.gov/; NCT01360398, registered May 25, 2011

scholarly journals High degree of virulence gene diversity in Streptococcus pyogenes isolated in Central Italy

2017 ◽  
Author(s):  
Daniela Bencardino ◽  
Maria Chiara Di Luca ◽  
Dezemona Petrelli ◽  
Manuela Prenna ◽  
Luca Agostino Vitali
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Central Italy ◽  
Virulence Gene ◽  
T Antigen ◽  
Gene Profiling ◽  
Important Species ◽  
Multiple Loci ◽  
Genetic Features

AbstractGlobally, Streptococcus pyogenes poses a continuous burden on human health, causing both self-limiting and life-threatening diseases. Therefore, studying the profile of virulence genes and their combinations is essential to monitor the epidemiology and pathogenetic potential of this important species. Thus, the aim of this study was to analyze some genetic features of clinical strains collected in Italy in 2012.We conducted fibronectin-collagen-T antigen (FCT) region typing and emm typing in 122 S. pyogenes strains. Furthermore, several additional virulence genes were screened by polymerase chain reaction.We found correlations between emm types and FCT region profiles. emm1 strains were mainly associated with FCT2 and FCT6, while emm89 and emm12 strains were associated with FCT4. FCT5 was mainly represented in emm4, emm6, and emm75 strains. Noteworthy, we defined subtypes for each FCT type based on the differences in single and multiple loci compared to the reference scheme used for the classification of the FCT region. In addition, new FCT types were identified. Cluster analysis based on virulence gene profiling showed a non-random distribution within each emm type.This study showed the high variability of S. pyogenes strains and the great diversification that this pathogen has undergone during its evolution in the human host.

scholarly journals High virulence gene diversity in Streptococcus pyogenes isolated in Central Italy

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6613 ◽  
Author(s):  
Daniela Bencardino ◽  
Maria Chiara Di Luca ◽  
Dezemona Petrelli ◽  
Manuela Prenna ◽  
Luca Agostino Vitali
Keyword(s):  
Streptococcus Pyogenes ◽  
Virulence Genes ◽  
Gene Diversity ◽  
Central Italy ◽  
Virulence Gene ◽  
T Antigen ◽  
Gene Profiling ◽  
Pathogenic Potential ◽  
Important Species ◽  
Multiple Loci

Globally, Streptococcus pyogenes poses a continuous burden on human health, causing both self-limiting and life-threatening diseases. Therefore, studying the profile of virulence genes and their combinations is essential to monitor the epidemiology and pathogenic potential of this important species. Thus, the aim of this study was to analyze related genetic features of clinical strains collected in Italy in 2012 in order to obtain a valid picture of their virulence profile that could be compared to similar studies made in other countries approximately in the same period. We conducted emm typing and fibronectin-collagen-T antigen (FCT) region typing in 122 Streptococcus pyogenes strains. Furthermore, several additional virulence genes were screened by polymerase chain reaction. We found correlations between emm types and FCT region profiles. emm1 strains were mainly associated with FCT2 and FCT6, while emm89 and emm12 strains were associated with FCT4. FCT5 was mainly represented in emm4, emm6, and emm75 strains. Significantly, we defined subtypes for each FCT type based on the differences in single and double loci compared to the reference scheme used for the classification of the FCT region. In addition, new FCT-region variants with differences in multiple loci were also recorded. Cluster analysis based on virulence gene profiling showed a non-random distribution within each emm type. This study added new data to existing studies conducted worldwide and revealed new variability scores in circulating Streptococcus pyogenes strains and new assortments in well-established virulence gene signatures.

scholarly journals Indirect Pathogenicity of Haemophilus influenzae and Moraxella catarrhalis in Polymicrobial Otitis Media Occurs via Interspecies Quorum Signaling

mBio ◽  
2010 ◽  
Vol 1 (3) ◽  
Author(s):  
Chelsie E. Armbruster ◽  
Wenzhou Hong ◽  
Bing Pang ◽  
Kristin E. D. Weimer ◽  
Richard A. Juneau ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Otitis Media ◽  
Moraxella Catarrhalis ◽  
Bacterial Species ◽  
Polymicrobial Infection ◽  
Infection Model ◽  
Resistance To Antibiotics ◽  
Autoinducer 2 ◽  
Airway Infections ◽  
The Impact

ABSTRACTOtitis media (OM) is among the leading diseases of childhood and is caused by opportunists that reside within the nasopharynx, such asHaemophilus influenzaeandMoraxella catarrhalis. As with most airway infections, it is now clear that OM infections involve multiple organisms. This study addresses the hypothesis that polymicrobial infection alters the course, severity, and/or treatability of OM disease. The results clearly show that coinfection withH. influenzaeandM. catarrhalispromotes the increased resistance of biofilms to antibiotics and host clearance. UsingH. influenzaemutants with known biofilm defects, these phenotypes were shown to relate to biofilm maturation and autoinducer-2 (AI-2) quorum signaling. In support of the latter mechanism, chemically synthesized AI-2 (dihydroxypentanedione [DPD]) promoted increasedM. catarrhalisbiofilm formation and resistance to antibiotics. In the chinchilla infection model of OM, polymicrobial infection promotedM. catarrhalispersistence beyond the levels seen in animals infected withM. catarrhalisalone. Notably, no such enhancement ofM. catarrhalispersistence was observed in animals infected withM. catarrhalisand a quorum signaling-deficientH. influenzae luxSmutant strain. We thus conclude thatH. influenzaepromotesM. catarrhalispersistence within polymicrobial biofilms via interspecies quorum signaling. AI-2 may therefore represent an ideal target for disruption of chronic polymicrobial infections. Moreover, these results strongly imply that successful vaccination against the unencapsulatedH. influenzaestrains that cause airway infections may also significantly impact chronicM. catarrhalisdisease by removing a reservoir of the AI-2 signal that promotesM. catarrhalispersistence within biofilm.IMPORTANCEOtitis media (OM) is one of the most common childhood infections and is a leading reason for antibiotic prescriptions to children. Chronic and recurrent OM involves persistence of bacteria within biofilm communities, a state in which they are highly resistant to immune clearance and antibiotic treatment. While it is clear that most of these infections involve multiple species, the vast majority of knowledge about OM infections has been derived from work involving single bacterial species. There is a pressing need for better understanding of the impact of polymicrobial infection on the course, severity, and treatability of OM disease. In this study, we show that communication between bacterial species promotes bacterial persistence and resistance to antibiotics, which are important considerations in the diagnosis, prevention, and treatment of OM. Moreover, the results of this study indicate that successful preventive measures againstH. influenzaecould reduce the levels of disease caused byM. catarrhalis.

scholarly journals Selection, Recombination, and Virulence Gene Diversity among Group B Streptococcal Genotypes

2009 ◽  
Vol 191 (17) ◽  
pp. 5419-5427 ◽  
Author(s):  
A. Cody Springman ◽  
David W. Lacher ◽  
Guangxi Wu ◽  
Nicole Milton ◽  
Thomas S. Whittam ◽  
...  
Keyword(s):  
Virulence Genes ◽  
Fragment Length Polymorphism ◽  
Gene Diversity ◽  
Virulence Gene ◽  
Polymorphism Analysis ◽  
Neonatal Disease ◽  
Gene Profiles ◽  
Phylogenetic Lineages ◽  
Group B ◽  
Sequence Types

ABSTRACT Transmission of group B Streptococcus (GBS) from mothers to neonates during childbirth is a leading cause of neonatal sepsis and meningitis. Although subtyping tools have identified specific GBS phylogenetic lineages that are important in neonatal disease, little is known about the genetic diversity of these lineages or the roles that recombination and selection play in the generation of emergent genotypes. Here, we examined genetic variation, selection, and recombination in seven multilocus sequence typing (MLST) loci from 94 invasive, colonizing, and bovine strains representing 38 GBS sequence types and performed DNA sequencing and PCR-based restriction fragment length polymorphism analysis of several putative virulence genes to identify gene content differences between genotypes. Despite the low level of diversity in the MLST loci, a neighbor net analysis revealed a variable range of genetic exchange among the seven clonal complexes (CCs) identified, suggesting that recombination is partly responsible for the diversity observed between genotypes. Recombination is also important for several virulence genes, as some gene alleles had evidence for lateral gene exchange across divergent genotypes. The CC-17 lineage, which is associated with neonatal disease, is relatively homogeneous and therefore appears to have diverged independently with an exclusive set of virulence characteristics. These data suggest that different GBS genetic backgrounds have distinct virulence gene profiles that may be important for disease pathogenesis. Such profiles could be used as markers for the rapid detection of strains with an increased propensity to cause neonatal disease and may be considered useful vaccine targets.

Moraxella catarrhalis-Infektion-– prognostische Bedeutung im Vergleich zu Haemophilus influenzae-Infektion

Pneumologie ◽  
2005 ◽  
Vol 59 (S 1) ◽  
Author(s):  
E Kramme ◽  
J Rupp ◽  
B Schaaf ◽  
M Maaß ◽  
P Zabel ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Moraxella Catarrhalis

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Penaeus Monodon ◽  
Challenge Test ◽  
Virulence Gene ◽  
Economic Losses ◽  
Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

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