Use this URL to cite or link to this record in EThOS:
Title: Molecular typing and analysis of antimicrobial resistance in clinical isolates of Streptococcus pneumoniae and Haemophilus influenzae
Author: Bamarouf, Abdulaziz Omar
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2000
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
b-Lactams are widely used to treat S. pneumoniae and H. influenzae respiratory infections. However, resistance to b-lactams is increasing in the UK. To establish if this results from spread of a small number of resistant strains or from a wider emergence of resistance, the molecular type and mechanisms of resistance in S. pneumoniae and H. influenzae isolates, from throughout the UK, were determined. Resistance of S. pneumoniae to penicillin is due entirely to the development of altered forms of the high molecular weight penicillin binding proteins (PBPs) and decreased affinity of PBP 2x, 2b and 1a together give high-level penicillin resistance. Between 1995 and 1996, 80 isolates of s. pneumoniae were obtained from centres throughout the UK. Eighteen isolates were penicillin-resistant and these were typed by pulsed-field gel electrophoresis (PFGE). In addition, changes in penicillin binding proteins (PBPs) 2x, 2b and 1a were examined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Cluster analysis of patterns produced by PFGE of chromosomal DNA digested with Sma1 revealed that penicillin resistance was not simply the result of clonal spread. Screening for changes in PBPs and RFLP of the amplified pbp2x, 2b and 1a genes by HinfI showed that there was a correlation between resistance and alteration in PBPs. The results indicate that penicillin resistance in S. pneumoniae in the UK is evolving in a variety of different strains and this raises cause for concern. b-Lactams resistance in H. influenzae is mainly mediated by the production of b-lactamases. b-lactamase-mediated resistance is associated with the production of TEM-1, ROB-1 and VAT-1 b-lactamase enzymes. Impermeability and alterations in PBPs are further mechanisms that mediate resistance to b-lactams. The epidemiology and mechanisms of resistance to amoxycillin and amoxycillin/clavulanic acid (co-amoxiclav) in H. influenzae isolates from the UK was examined. Between 1995 and 1996, 231 isolates of H. influenzae were obtained from centres throughout the UK. Twenty percent of isolates were amoxycillin-resistant and, of these, 19% were also resistant to co-amoxiclav.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available