Experience with the new genetic variant of Chlamydia trachomatis in Orebro county, Sweden - proportion, characteristics and effective diagnostic solution in an emergent situation.

A Chlamydia trachomatis variant that contains a 377 bp deletion in the cryptic plasmid was recently reported in Sweden. This deletion includes the targets for Cobas Amplicor, Cobas TaqMan48, and Abbott m2000. We examined the proportion and characteristics of this variant in Örebro county, Sweden and developed an effective diagnostic solution. In total, 2,401 consecutive C. trachomatis culture samples and 536 PCR samples from symptomatic and asymptomatic patients and screened females were included. Culture, Cobas Amplicor, and LightMix 480HT were used for diagnosis. A mutant-specific PCR, plasmid sequencing, omp1 sequencing and multilocus sequence typing (MLST) were used to identify and characterise mutants. In total, 162 (6.7%) of the cultured samples were positive for C. trachomatis. However, 61 (38%) of those were negative when using Cobas Amplicor, and 60 of these were subsequently confirmed as the new variant. 13 of these mutant isolates were further characterised genetically, and all were of identical genotype E and the unique MLST sequence type: 21, 19, 1, 2, 1. Of all culture-positive samples, 161 of 162 were positive in the LightMix 480HT assay. The single negative sample was only weakly positive in culture, and negative in all PCRs. Of the 536 PCR samples, 37 were positive in both Cobas Amplicor and LightMix 480HT, 13 were only positive in LightMix 480HT (mutants), and two were only positive in Cobas Amplicor. Mutated C. trachomatis were prevalent in Örebro county in the period from October 2006 to February 2007, and it appeared to be a single clone. LightMix 480HT seemed sensitive, specific, and enabled high throughput diagnostics. However, rare low positive samples may be false-negative. Frequent surveillance and evaluations of diagnostic methods worldwide are crucial

Molecular typing methods for outbreak detection and surveillance of invasive disease caused by Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae, a review.

Invasive disease caused by the encapsulated bacteria Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae remains an important cause of morbidity and mortality worldwide, despite the introduction of successful conjugate polysaccharide vaccines that target disease-associated strains. In addition, resistance, or more accurately reduced susceptibility, to therapeutic antibiotics is spreading in populations of these organisms. There is therefore a continuing requirement for the surveillance of vaccine and non-vaccine antigens and antibiotic susceptibilities among isolates from invasive disease, which is only partially met by conventional methods. This need can be met with molecular and especially nucleotide sequence-based typing methods, which are fully developed in the case of N. meningitidis and which could be more widely deployed in clinical laboratories for S. pneumoniae and H. influenzae

Varicella vaccination in Europe: are we ready for a universal childhood program?

Safe and effective vaccines against varicella zoster virus (VZV), the aetiological agent of varicella and shingles, have been available in Europe for the last 5-10 years. The USA has had a universal childhood vaccination policy since 1995 and this has resulted in a dramatic decrease in the incidence, morbidity and mortality related to varicella. The economic and medical burden of VZV has led to discussions regarding both the desirability and feasability of a similar routine immunisation policy for all European children. This article examines the epidemiology of varicella in Europe and how the data emerging from the USA can be used to achieve adequate prevention of the disease. It looks into the current evidence of the health economic evaluation of universal varicella vaccination and explores the concerns surrounding such a policy, including the postulated impact on the incidence of zoster. In conclusion, the Society of Independent European Vaccination Experts (SIEVE) recommends that the immunisation of susceptible adolescents needs to be urgently implemented, in addition to the current recommendations targeting high-risk patients, their close contacts with a negative history of varicella and seronegative health-care workers. A universal policy, optimally incorporating a two-dose schedule, will be needed to finally reduce the burden of disease of varicella from a societal point of view. The SIEVE recommends the implementation of such a policy as soon as financially and practically possible