Diversity of antibiotic resistance integrative and conjugative elements among haemophili.

The objective of this study was to investigate the sequence diversity in a single country of a family of integrative and conjugative elements (ICEs) that are vectors of antibiotic resistance in Haemophilus influenzae and Haemophilus parainfluenzae, and test the hypothesis that they emerged from a single lineage. Sixty subjects aged 9 months - 13 years were recruited and oropharyngeal samples cultured. Up to 10 morphologically distinct Pasteurellaceae spp. were purified, and then the species were determined and differentiated by partial sequence analysis of 16S rDNA and mdh, respectively. ICEs were detected by PCR directed at five genes distributed evenly across the ICE. These amplicons were sequenced and aligned by the neighbour-joining algorithm. A total of 339 distinguishable isolates were cultured. ICEs with all 5 genes present were found in 9 of 110 (8 %) H. influenzae and 21 of 211 (10 %) H. parainfluenzae, respectively. ICEs were not detected among the other Pasteurellaceae. A total of 20 of 60 (33 %) children carried at least 1 oropharyngeal isolate with an ICE possessing all 5 genes. One of the five genes, integrase, however, consisted of two lineages, one of which was highly associated with H. influenzae. The topology of neighbour-joining trees of the remaining four ICE genes was compared and showed a lack of congruence; though, the genes form a common pool among H. influenzae and H. parainfluenzae. This family of antibiotic resistance ICEs was prevalent among the children studied, was genetically diverse, formed a large gene pool, transferred between H. influenzae and H. parainfluenzae, lacked population structure and possessed features suggestive of panmixia, all indicating it has not recently emerged from a single source

Relationship between nosocomial Acinetobacter species occurring in two geographical areas (Greece and the UK).

Fifty-two isolates of Acinetobacter spp. obtained from three Greek and one UK hospital, were studied using partial 16 S ribosomal DNA sequence analysis, repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR) mediated fingerprinting and DNA macro-restriction analysis. The aim was twofold: first, to discern the major differences in the population of Acinetobacter spp. between the two countries. Second, to compare a simple PCR-based typing scheme with pulsed-field gel electrophoresis (PFGE). The multi-resistant Greek isolates were within DNA groups 2 and TU13, and clustered into three types both by REP-PCR and PFGE. By contrast, the more susceptible Oxford isolates were heterogeneous on 16 S RNA sequence analysis and distinguishable on typing. The need for studies that elucidate the phylogeny of Acinetobacter spp. inside and outside hospitals are important, as this will help clarify the relationship between organisms that are increasingly recognized as causes of severe infections