Treatment failure with penicillin in early syphilis

[Syphilis treatment. German and international guidelines--a comparison]

Guidelines are an important instrument for improving the quality of medical care. In 2001, the German STD Society (DSTDG) published guidelines for syphilis diagnostics and treatment. For two reasons, these guidelines had to be reviewed urgently: Firstly, there is an obvious "renaissance" of syphilis among men having sex with men, which is complicated by a frequent comorbidity with HIV infection. Secondly, the standard drug for syphilis treatment in Germany, clemizole penicillin, has no longer been available since July 2003. In this article, the new German guidelines for syphilis treatment 2004, published by the DSTDG, are compared with other syphilis guidelines, which are valid for the European countries, i.e., the CDC, UK, Russian, and European guidelines 2002.

Antibiotics for syphilis diagnosed during pregnancy

BACKGROUND

Congenital syphilis is an increasing problem in many developing countries and in the transitional economies of Eastern Europe and the former Soviet Union. In several countries this increase has been aggravated by HIV/AIDS. While the effectiveness of penicillin in the treatment of syphilis in pregnant women and the prevention of congenital syphilis was established shortly after the introduction of penicillin in the 1940s, there is uncertainty about the optimal treatment regimens.

OBJECTIVES

To identify the most effective antibiotic treatment regimen (in terms of dose, length of course and mode of administration) of syphilis with and without concomitant infection with HIV for pregnant women infected with syphilis.

SEARCH STRATEGY

MEDLINE 1966 to March 2000; EMBASE 1974 to March 2000, the Cochrane Controlled Trials Register (last searched March 2001), the Cochrane Pregnancy and Childbirth group trials register (last searched March 2001) and the references of traditional reviews were searched. Experts in specialist units were contacted.

SELECTION CRITERIA

It was planned that any trial in which an attempt is made to allocate treatment for syphilis during pregnancy by a random or quasi-random method would be included in this review.

DATA COLLECTION AND ANALYSIS

Information was extracted using a data extraction sheet and this included entry criteria, the source of controls, and whether the authors stratified by the stage of pregnancy when the diagnosis of syphilis was made.

MAIN RESULTS

Twenty six studies met the criteria for detailed scrutiny. However, none of these met the pre-determined criteria for comparative groups and none included comparisons between randomly allocated groups of pregnant women.

REVIEWER'S CONCLUSIONS

While there is no doubt that penicillin is effective in the treatment of syphilis in pregnancy and the prevention of congenital syphilis, uncertainty remains about what are the optimal treatment regimens. Further studies are needed to evaluate treatment failure cases with currently recommended regimens and this should include an assessment of the role of HIV infection in cases of prenatal syphilis treatment failure. The effectiveness of various antibiotic regimens for the treatment of primary and secondary syphilis in pregnant women need to be assessed using randomised controlled trials which compare them with existing recommendations.

In vitro culture system to determine MICs and MBCs of antimicrobial agents against Treponema pallidum subsp. pallidum (Nichols strain)

A new procedure for determining the susceptibility of Treponema pallidum subsp. pallidum to antimicrobial agents was developed, utilizing a tissue culture system which promotes the in vitro multiplication of this organism. In the absence of antibiotics, T. pallidum (Nichols virulent strain) multiplied an average of 10-fold when incubated for 7 days in the presence of Sf1Ep cottontail rabbit epithelial cell cultures. Varied concentrations of penicillin G, tetracycline, erythromycin, and spectinomycin were added to triplicate cultures to determine their effects on treponemal multiplication, motility, and virulence. The MIC of each antibiotic was defined as the lowest concentration which prevented treponemal multiplication, whereas the MBC was defined as the lowest concentration which abrogated the ability of the cultured treponemes to multiply and cause lesions in rabbits. The in vitro culture technique provided highly reproducible MICs and (in parentheses) MBCs of each of the antibiotics tested: aqueous penicillin G, 0.0005 (0.0025) microgram/ml; tetracycline, 0.2 (0.5) microgram/ml; erythromycin, 0.005 (0.005) microgram/ml; and spectinomycin, 0.5 (0.5) microgram/ml. The significance of these results in light of the in vivo activities and the previous in vitro evaluations of these antibiotics is discussed. The T. pallidum in vitro cultivation system shows promise as a method for studying the interaction between T. pallidum and antimicrobial agents and for screening new antibiotics for syphilis therapy.

Kinetic study of serum penicillin concentrations after single doses of benzathine and benethamine penicillins in young and old people

In a comparative kinetic study of the serum concentrations of two penicillin complexes--medium-long-acting (benethamine penicillin) and long-acting (benzathine bipenicillin)--after a single injection in young adults and elderly people, the following results were confirmed statistically: (a) age was a major factor in the variations in serum penicillin concentrations and in their persistence in the serum; (b) the penicillin was absorbed faster in young than in elderly subjects even when a long-acting complex was used; (c) serum concentrations below the level regarded as lethal for treponemes appeared much earlier and more frequently in young than in old people; and (d) the bioequivalence between penicillin preparations could not be estimated solely for the number of units of the agent used but from the bioavailability of the chosen formulation. Thus a uniform and standard penicillin dosage allowing no safety margin may help in the superficial healing of a syphilitic chancre or the resolution of a roseola but it will certainly be insufficient to kill Treponema pallidum. It seems essential therefore to provide an antibiotic cover at high dosage over a long period of time.