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C H Tremlett

Publications and source records attributed to C H Tremlett.

9 recordsLinked to original sources

Pre-transplantation testing: who, when and why?

An ever-widening range of human organs and tissues is being transplanted, limited currently only by the ingenuity of surgeons and immunologists to overcome the physical and immune barriers. Microbiologists are in danger of being left behind. Although the major infective risks of human organ transplantation are now well understood, many details remain controversial, and the special risks associated with tissue banking have received little attention until recently. What should we do? Are we making mountains out of molehills? Are there any data on which to base a rational decision? Topics covered include: bacteriology of cadaveric heart valve transplantation (why are valves not cultured and only dunked in antibiotic solution for 24h, whereas endocarditis gets treated for 4 weeks?); screening for tissue-born viruses (why does everyone persist with serology when genomic methods are so much better?); screening organ donors for CMV (surely we should use the optimally sensitive combination of methods?); peripheral blood stem cell transplants (should we culture these, and what do the positive results mean if we do?); donor sputum screening before heart-lung transplantation (does this aid the post-operative management of the recipient?). With active participation from the floor some areas of consensus were identified and topics worthy of scientific investigation in the future were highlighted.

Heart Valves↗

Variation in structure and location of VanA glycopeptide resistance elements among enterococci from a single patient.

Forty-six VanA glycopeptide-resistant enterococci (GRE) from a single patient were investigated for variation in structure and location of VanA resistance elements. Together with identification to species level and pulsed-field gel electrophoresis, these data divided the GRE into 10 groups and subgroups. Combining data in this manner appears helpful when investigating the epidemiology of GRE.

Bacterial Proteins↗

Molecular analysis of diverse elements mediating VanA glycopeptide resistance in enterococci.

Differences were examined among 24 distinct elements mediating VanA-type glycopeptide resistance in enterococci isolated from hospital patients and non-human sources in the UK. The methods used included long-PCR restriction fragment length polymorphism (L-PCR RFLP) analysis and DNA hybridization. All elements had conserved vanRSHAX genes, but variation occurred upstream of vanR and downstream of vanX. Twenty-one VanA elements had significant alterations upstream of vanR in the transposition genes orf1 and orf2: either parts of these genes were absent or they were disrupted by IS1216V or IS3-like insertion sequences. Among VanA elements with alterations downstream of vanX, seven lacked vanY, one lacked both vanY and vanZ, and ten had copies of insertion sequence IS1216V between vanX and vanY. All VanA elements of group D (from geographically and temporally diverse enterococci) were characterized by the presence of an IS1216V/IS3-like/orf1 complex and a point mutation in vanX, both of which were absent from the other 23 groups of VanA elements. This finding is consistent with the dissemination of a stable resistance element. We conclude that L-PCR RFLP analysis, combined with DNA hybridization, merits further development for studying the evolution and epidemiology of VanA resistance elements in enterococci.

Animals↗

Capsular serotypes and antibiotic sensitivity of Streptococcus pneumoniae isolated from primary-school children.

A total of 1049 primary-school children in 18 schools were screened for carriage of Streptococcus pneumoniae. Data on family size, antibiotic use, travel and hospital admissions were collected. Pneumococcal serotyping and sensitivity tests were performed. One third of children were found to be pneumococcal carriers. Ten of 344 isolates were penicillin-resistant (2.9%). Apart from resistance to trimethoprim and ciprofloxacin, resistance rates in penicillin-sensitive strains were low. Among penicillin-resistant strains (PRP), co-resistance to trimethoprim, chloramphenicol and tetracycline was common. Cefotaxime-resistance was seen in 90% of PRP. Although 24 serotypes were represented, groups 6, 19 and 23 accounted for 55% of strains. Serogroup 23 strains were significantly more likely to be penicillin-resistant than other groups/types. Clustering of strains by serotype and antibiotic resistance was seen in several schools. No association with foreign travel, family size or age of siblings was seen and penicillin resistance was not associated with prior antibiotic use. However, hospital admission was significantly associated with carriage of PRP. The implications of detecting PRP in the community are discussed.

Anti-Bacterial Agents↗