Seven years of teenage pregnancy in an inner London genitourinary medicine service - a retrospective cohort study.

Young people attending genitourinary medicine services are at high risk of unplanned pregnancy. We performed a retrospective cohort study to identify characteristics of pregnant teenagers accessing an inner London genitourinary medicine service. There were 481 pregnancies in 458 teenagers with 54 previous pregnancies and 46 previous terminations of pregnancy. The under-18 and under-16 teenage pregnancy rates were 92.1 and 85.8 per 1000 age-matched clinic attendees, respectively. Median age was 17.1 years. 'Black Other' teenagers ('Black British', 'Mixed White-Black Caribbean' and 'Mixed White-Black African') were over-represented, compared to our clinic population, while those of White ethnicity were under-represented. Few pregnancies (1.5%) were planned with the majority (64%) intending terminations of pregnancy. Most teenagers did not use consistent contraception. Two-thirds of patients had attended genitourinary medicine services in the past and sexually transmitted infection prevalence at presentation was high. Effectively targeting the sexual and reproductive health needs of teenage genitourinary medicine clinic attendees may have a significant impact on reducing sexually transmitted infections, unplanned pregnancy and terminations of pregnancy in this group.

Penicillin facilitates the entry of antisense constructs into Streptococcus mutans.

Antisense oligonucleotides (AS-ODN) target genes in a sequence-specific manner inhibit gene function and have potential use as antimicrobial agents. Cell barriers, such as peptidoglycan, cell surface proteins and lipopolysaccharide membranes, prevent delivery of AS-ODN into the bacterial cell, limiting their use as an effective treatment option. The ß-lactam antibiotic penicillin was examined for its ability to deliver phosphorothioate oligodeoxyribonucleotides (PS-ODNs) and γ(32) P-ODN into Streptococcus mutans OMZ175. Treatment of lag-phase S. mutans OMZ175 cells with penicillin and FBA (PS-ODN targeting the fructose-biphosphate aldolase gene), resulted in prolonged suppression of growth (> 24 h) and fba expression (656.9 ± 194.4-fold decrease at 5 h). Suppression of both cell growth and fba expression corresponded with a greater amount of γ(32) P-ODN becoming cell associated, with a maximum γ(32) P-ODN concentration per cell achieved 5 h after penicillin treatment (6.50 ± 1.39 × 10(8) molecules per CFU). This study confirms that for S. mutans OMZ175, the peptidoglycan layer acts as a major barrier preventing AS-ODN penetration and suggests that the use of agents such as penicillin that interfere with peptidoglycan integrity can significantly increase the uptake of PS-ODN by these cells.

Zoocin A facilitates the entry of antisense constructs into Streptococcus mutans.

The use of antisense oligodeoxyribonucleotides (asODNs) to inhibit gene function has proven to be an extremely powerful tool for establishing gene-function relationships. Diffusion limitations imposed by the thick peptidoglycan layer of Gram-positive bacteria have proven difficult to overcome for permeability of asODNs. Typically, introduction of the asODN is achieved by cloning the antisense sequence into a vector downstream of an inducible promoter and transforming this construct into the cell of interest. In this study, we report that the use of the streptococcolytic enzyme zoocin A facilitated entry of phosphorothioate oligodeoxyribonucleotides (PS-ODNs) into Streptococcus mutans, such that the degree of phenotypic response (cell growth inhibition) observed was sequence specific and correlated with the amount of zoocin A (R(2) =0.9919) or PS-ODN (R(2) =0.9928) used. Quantitative reverse transcriptase PCR was used to demonstrate that only the expression of the target gene against which the PS-ODN was designed was affected. We believe that the use of an appropriate bacteriolytic enzyme to facilitate entry of asODNs into bacterial cells provides a method that will be generally useful in the study of gene regulation in Gram-positive bacteria.