A high incidence of antimicrobial resistance in Group B Streptococcus (GBS) clinical isolates with poor biofilm forming capacity

Background: Group B Streptococcus (GBS) or commonly known as Streptococcus agalactiae are the leading cause of bacterial meningitis and bacterial sepsis in newborns. One of the virulence factors is the biofilm forming capacity of the isolates which may promote adherence and survivability leading to invasion of GBS at the infected sites. In a previous study conducted by Kaur et al., (2009), biofilm formation has been associated with virulence level among the GBS clinical isolates. We had previously characterized a collection of GBS clinical isolates from invasive and colonizing site for serotypes and antimicrobial susceptibility pattern (Emir et al., 2014). In this study, we extended the study by looking into biofilm formation capability of the GBS isolates and analysed the phenotypic pattern in relation to isolation site, serotypes and antibiotics susceptibility pattern for a potential association. Materials and Methods: A total of 51 viable GBS isolates were available in our collection with pre-determined data for serotypes (by multiplex PCR) and antimicrobial susceptibility pattern (by disk diffusion) for erythromycin, clindamycin, trimethoprim sulfamethoxazole, tetracycline, chloramphenicol and penicillin (Emir et al., 2014). The isolates were previous collected from three different hospitals in Klang Valley (n=51). A total of 29 isolates were from colonizing site and another 23 isolates from invasive sites. In this study, the capacity of biofilm formation of GBS was determined by OD-based biofilm assay as described by Kaur et al., (2009). The GBS isolates were considered as good biofilm former based on ODA550 reading >1.0, moderate biofilm former at ODA550 value between 0.5-1.0 and poor biofilm former of ODA550 value <0.5. The tabulation of the categories was compared in relation to the isolation site and previously determined phenotypic and genotypic properties. Results and Conclusion: Based on the OD-based criteria, none of the 51 isolates had good biofilm formation while 11 had moderate and the rest were poor biofilm forming isolates. The proportions of colonizing and invasive isolated were about equal among the moderate and poor biofilm former (45-55%). In relation to antibiotic susceptibility pattern, a majority of those resistant to all tested antibiotics were poor biofilms formers. That in relation to penicillin was not known as there was only one isolates with penicillin intermediate. Six isolates of poor biofilm former and one isolates of moderate biofilm former were identified as multidrug resistant strains (MDR) which are resistant to at least three antibiotics of different classes. Nonetheless, chi square analysis showed none of the categorical tabulation had a significant association. This could be due to the limited number of representative isolates in the categories although obvious differences based on percentage (%) were observed for some of the antibiotics. This limitation also applied in relation to serotype due to its variability which resulted in low representative for some of the serotypes include (serotype II, type III, type V, type VI and type VIII) among the 51 isolates. Serotype Ia had the highest prevalence (n=22) but interestingly 20 of them were poor biofilm formers. For the other respective serotypes, the distribution rate in relation to moderate and poor biofilm were about equal. As far as this study is concerned, there is no specific preference for colonizing and invasive GBS isolates to have certain advantage in term of biofilm capacity. In a study conducted by Talat et al., (2012), serotype Ia and IV were associated with tendency to form biofilm which was in contrast with this study. The tendency of antibiotic resistance to present more among poor biofilm formers in this study are also of the interest to be further elucidated. Further studies also required to define more precisely the effect of antibiotic resistance in biofilm forming GBS isolates

Zika Virus Encoding Nonglycosylated Envelope Protein Is Attenuated and Defective in Neuroinvasion

ABSTRACT Zika virus (ZIKV), a mosquito-transmitted flavivirus responsible for sporadic outbreaks of mild and febrile illness in Africa and Asia, reemerged in the last decade causing serious human diseases, including microcephaly, congenital malformations, and Guillain-Barré syndrome. Although genomic and phylogenetic analyses suggest that genetic evolution may have led to the enhanced virulence of ZIKV, experimental evidence supporting the role of specific genetic changes in virulence is currently lacking. One sequence motif, VNDT, containing an N-linked glycosylation site in the envelope (E) protein, is polymorphic; it is absent in many of the African isolates but present in all isolates from the recent outbreaks. In the present study, we investigated the roles of this sequence motif and glycosylation of the E protein in the pathogenicity of ZIKV. We first constructed a stable full-length cDNA clone of ZIKV in a novel linear vector from which infectious virus was recovered. The recombinant ZIKV generated from the infectious clone, which contains the VNDT motif, is highly pathogenic and causes lethality in a mouse model. In contrast, recombinant viruses from which the VNDT motif is deleted or in which the N-linked glycosylation site is mutated by single-amino-acid substitution are highly attenuated and nonlethal. The mutant viruses replicate poorly in the brains of infected mice when inoculated subcutaneously but replicate well following intracranial inoculation. Our findings provide the first evidence that N-linked glycosylation of the E protein is an important determinant of ZIKV virulence and neuroinvasion. IMPORTANCE The recent emergence of Zika virus (ZIKV) in the Americas has caused major worldwide public health concern. The virus appears to have gained significant pathogenicity, causing serious human diseases, including microcephaly and Guillain-Barré syndrome. The factors responsible for the emergence of pathogenic ZIKV are not understood at this time, although genetic changes have been shown to facilitate virus transmission. All isolates from the recent outbreaks contain an N-linked glycosylation site within the viral envelope (E) protein, whereas many isolates of the African lineage virus lack this site. To elucidate the functional significance of glycosylation in ZIKV pathogenicity, recombinant ZIKVs from infectious clones with or without the glycan on the E protein were generated. ZIKVs lacking the glycan were highly attenuated for the ability to cause mortality in a mouse model and were severely compromised for neuroinvasion. Our studies suggest glycosylation of the E protein is an important factor contributing to ZIKV pathogenicity

Everolimus-eluting bioresorbable vascular scaffolds for treatment of complex chronic total occlusions

AIMS: Bioresorbable vascular scaffolds (BVS) represent a novel therapeutic option for the treatment of coronary artery diseases. The objective of this study was to evaluate the feasibility of BVS implantation in complex chronic total occlusions (CTO). METHODS AND RESULTS: The present report is a multicentre registry evaluating results after BVS deployment in challenging CTO lesions, defined as J-CTO score >/=2 (difficult or very difficult). A total of 105 patients were included in the present analysis. The mean J-CTO score was 2.61 (difficult 52.4%, very difficult 47.6%). Device success and procedural success rates were 98.1% and 97.1%, respectively. The retrograde approach was used in 25.7% of cases. After wire crossing, predilatation was performed in all cases with a mean predilatation balloon diameter of 2.73+/-0.43 mm. The mean scaffold length was 59.75+/-25.85 mm, with post-dilatation performed in 89.5% of the cases and a mean post-dilatation balloon diameter of 3.35+/-0.44 mm. Post-PCI minimal lumen diameter was 2.50+/-0.51 mm and percentage diameter stenosis 14.53+/-10.31%. At six-month follow-up, a total of three events were reported: one periprocedural myocardial infarction, one late scaffold thrombosis and one additional target lesion revascularisation. CONCLUSIONS: The present report suggests the feasibility of BVS implantation in complex CTO lesions, given adequate lesion preparation and post-dilatation, with good acute angiographic results and midterm clinical outcomes