P59 Serological response to different antibiotic treatments of neurosyphilis

Abstract

<h3>Introduction</h3> Current recommended first-line treatment for neurosyphilis (NS) is penicillin, with doxycycline and ceftriaxone as second-line alternatives. This is an observational study of serological response to treatment for suspected NS with penicillin, compared to alternatives, within a single NHS trust. <h3>Methods</h3> Data were retrospectively collected for individuals with suspected NS who had cerebrospinal fluid (CSF) sampling between 01/2017-01/2022, including demographics and serum rapid plasma reagin (RPR). NS was defined as positive syphilis serology with ≥1 neurological symptom and either a positive CSF RPR, a CSF Treponema pallidum particle agglutination assay (TPPA) titre of &gt;1:320 or a positive CSF TPPA with a high index of clinical suspicion. Serological response was defined as a ≥4-fold decrease in serum RPR titres at six- or 12-months post-treatment. <h3>Results</h3> Of 78 patients investigated for NS, the median age was 42 (IQR 34.5-51) years. 72/78 were male (92%), 57/78 were MSM (73%) and 46/78 (59%) were living with HIV (median CD4 count 563cells/μl (IQR 400-859)). 32/78 met the definition of NS. 19/32 (59%) received penicillin, 6/32 (19%) ceftriaxone, 5/32 (16%) doxycycline and 2/32 (6%) received ceftriaxone+penicillin. 10/32 had no follow-up RPR available. Six- and 12-month serological response rates for penicillin group were 8/12 (67%) and 8/8 (100%) respectively, compared to 2/6 (33%) and 2/3 (66%) for ceftriaxone or doxycycline alone (Table 1). <h3>Conclusion</h3> At 12 months, ceftriaxone has a similar serological response rate compared to penicillin in NS treatment, however, penicillin has favourable rates at six months over alternative treatments, although this was not statistically significant.