Molecular Basis of Increased Serum Resistance among Pulmonary Isolates of Non-typeable Haemophilus influenzae

Non-typeable Haemophilus influenzae (NTHi), a common commensal of the human pharynx, is also an opportunistic pathogen if it becomes established in the lower respiratory tract (LRT). In comparison to colonizing isolates from the upper airway, LRT isolates, especially those associated with exacerbations of chronic obstructive pulmonary disease, have increased resistance to the complement- and antibody-dependent, bactericidal effect of serum. To define the molecular basis of this resistance, mutants constructed in a serum resistant strain using the mariner transposon were screened for loss of survival in normal human serum. The loci required for serum resistance contribute to the structure of the exposed surface of the bacterial outer membrane. These included loci involved in biosynthesis of the oligosaccharide component of lipooligosaccharide (LOS), and vacJ, which functions with an ABC transporter encoded by yrb genes in retrograde trafficking of phospholipids from the outer to inner leaflet of the cell envelope. Mutations in vacJ and yrb genes reduced the stability of the outer membrane and were associated with increased cell surface hyrophobicity and phospholipid content. Loss of serum resistance in vacJ and yrb mutants correlated with increased binding of natural immunoglobulin M in serum as well as anti-oligosaccharide mAbs. Expression of vacJ and the yrb genes was positively correlated with serum resistance among clinical isolates. Our findings suggest that NTHi adapts to inflammation encountered during infection of the LRT by modulation of its outer leaflet through increased expression of vacJ and yrb genes to minimize recognition by bactericidal anti-oligosaccharide antibodies

Shoulda' put a ring on it:Investigating adult attachment, relationship status, anxiety, mindfulness, and resilience in romantic relationships

This study aimed to investigate the predictive ability of relationship status, anxiety, mindfulness, and resilience in relation to the two orthogonal dimensions of adult attachment: attachment anxie-ty and attachment avoidance. 156 participants completed measures assessing relationship status, adult attachment, anxiety, mindfulness and resilience. The results showed that resilience and the relationship status of single significantly predicted attachment anxiety, whereas anxiety and being either single or divorced significantly predicted attachment avoidance. A significant mediating role of resilience in the prediction of attachment anxiety from being single was also observed. The main implications of this study provided preliminary support for the significant predictive value of resilience in attachment anxiety

Escherichia coli of human and avian origin: detection of clonal groups associated with fluoroquinolone and multidrug resistance in Italy

Objectives: Poultry have been suggested as a reservoir for fluoroquinolone-resistant extraintestinal pathogenic Escherichia coli (ExPEC). Our aim was to investigate whether genotypes associated with ciprofloxacin and multidrug resistance were shared among human and avian E. coli. Methods: We compared 277 human ExPEC isolates from urinary tract infection (UTI) and sepsis (142 susceptible and 135 ciprofloxacin resistant) and 101 avian isolates (68 susceptible and 33 ciprofloxacin resistant) by antimicrobial resistance phenotype, phylogenetic group and multilocus sequence type (ST). Results: Most ciprofloxacin-resistant isolates from both human and avian sources were multidrug resistant. Human and avian isolates strongly differed in phylogenetic group assignment (B2 and A predominated among human and avian isolates, respectively), but a shift towards group A associated with ciprofloxacin resistance was observed among human isolates (8/100, 8.0% versus 17/87, 19.5%, P¼0.021 for UTI and 5/42, 11.9% versus 15/48, 31.3%, P¼0.028 for sepsis). Heterogeneity of ST clones was observed, with ST131 strongly predominant in human ciprofloxacin-resistant strains (58/135, 43.0%), but not in avian strains. However, two major ST clonal complexes (CCs; CC10 and CC23, both belonging to group A) associated with ciprofloxacin resistance and multiresistance were shared by human and avian isolates. Conclusions: The major human and avian E. coli ST clones associated with multidrug resistance were identified. A subset of ST clones belonging to CC10 and CC23 poses a potential zoonotic risk

Immunoglobulin enhancer HS1,2 polymorphism: A new powerful anthropogenetic marker

The human HS1,2 enhancer of the immunoglobulin (Ig) heavy chain 3' enhancer complex plays a central role in the regulation of Ig maturation and production. Four common alleles HS1,2-A*1, *2, *3, *4 are directly implicated with the transcription level and at least one of them, HS1, 2-A*2, seems to be related to immune disorders, such as coeliac disease, herpetiform dermatitis and Berger syndrome. Given their clinical significance it is of interest to know the distribution of HS1,2-A variants in populations from different continents, as well as to determine whether the polymorphism is associated to specific evolutionary factors. In this paper we report the distribution of the HS1,2-A polymorphism in 1098 individuals from various African, Asian and European populations. HS1,2-A*3 and HS1,2-A*4 alleles are at their highest frequencies among Africans, and HS1,2-A*2 is significantly lower in Africans in comparison with both Europeans and, to a lesser extent, Asians. Analysis of molecular variance of the allele frequencies indicates that the HS1,2-A polymorphism can be considered as a reliable anthropogenetic marker