Ethnically diverse urban transmission networks of Neisseria gonorrhoeae without evidence of HIV serosorting

Objective We aimed to characterise gonorrhoea transmission patterns in a diverse urban population by linking genomic, epidemiological and antimicrobial susceptibility data. Methods Neisseria gonorrhoeae isolates from patients attending sexual health clinics at Barts Health NHS Trust, London, UK, during an eleven-month period underwent whole-genome sequencing and antimicrobial susceptibility testing. We combined laboratory and patient data to investigate the transmission network structure. Results One hundred and fifty-eight isolates from 158 patients were available with associated descriptive data. One hundred and twenty-nine (82%) patients identified as male and 25 (16%) as female; 4 (3%) records lacked gender information. Self-described ethnicities were: 51 (32%) English/Welsh/Scottish; 33 (21%) White, other; 23 (15%) Black British/Black African/Black, other; 12 (8%) Caribbean; 9 (6%) South Asian; 6 (4%) mixed ethnicity; 10 (6%) other; data were missing for 14 (9%). Self-reported sexual orientations were 82 (52%) men who have sex with men; 49 (31%) heterosexual; 2 (1%) bisexual; data missing for 25 individuals. Twenty-two (14%) patients were HIV-positive. Whole genome sequence data were generated for 151 isolates, which linked 75 (50%) patients to at least one other case. Using sequencing data, we found no evidence of transmission networks related to specific ethnic groups (p=0.64) or of HIV serosorting (p=0.35). Of 82 MSM/bisexual patients with sequencing data, 45 (55%) belonged to clusters of ≥2 cases, compared to 16/44 (36%) heterosexuals with sequencing data (p=0.06). Conclusion We demonstrate links between 50% of patients in transmission networks using a relatively small sample in a large cosmopolitan city. We found no evidence of HIV serosorting. Our results do not support assortative selectivity as an explanation for differences in gonorrhoea incidence between ethnic groups

Prospective Analysis of Factors Influencing the Antibody Response to Hepatitis B Vaccine in Hemodialysis Patients

Abstract Background. Patients on maintenance hemodialysis typically show a suboptimal immune response to hepatitis B (HB) virus vaccination compared to the non-uremic population. The aim or our study was the identification of factors implicated in the vaccine response of our hemodialysis patients. Methods. We studied prospectively 63 hemodialysis patients who were seronegative for HB (37 males, 26 females). Their mean age was 62.2±11.28 years (range 35-80) and hemodialysis. Duration 55.96±50.1 months (range 6-225) fourteen of them (22.2%) were diabetics. Our patients followed a four-dose vaccination schedule (0, 1, 2 and 6 months) with 40 μg of a recombinant DNA HB vaccine. The antibody response was determined 1 month after the fourth dose of vaccination by assessing the titre of antiHBs antibodies (ab). Immune response was defined as sufficient when the antiHBs ab level was ≥ 12 mIU/ml. During the 6-month vaccination period we also monitored monthly and time-averaged Kt/V, residual renal function (RRF), BMI, serum creatinine, albumin, transferrin, ferritin, CRP, iPTH and the dose of erythropoietin and Vitamin D that they received. Results. An optimal immune response was achieved in 34 patients (54%, responders) (antiHBs: 295.95±341.67 mIU/ml), whereas 29 patients (46%, non-responders) showed a suboptimal response (antiHBs: 1.98±2.92 mIU/ml) (p=1.75x10 -5 ). There was a statistically significant negative correlation between the antiHBs ab titre and BMI (r=-0.28, p=0.024). A significant difference was also found between the BMI of responders and non-responders as groups (24.8±5.5 vs. 27.2±4.5, p=0.02). Grouping our patients according to the existence of diabetes, age (cut off 60 years), and hemodialysis efficiency (Kt/V≥1.2) we found a statistically significant difference in the antiHBs ab titre between diabetics and non-diabetics (8.43±12.3 vs. 200.2±317.7 mIU/ml, p=0.03), younger and older patients (262±365.09 vs. 84.36±189.1 mIU/ml, p=0.0145) and patients with efficient and inefficient hemodialysis (234.71±337.1 vs. 79.14±200.99 mIU/ml, p=0.032). Treatment with vitamin D analogues, RRF and hypoalbuminemia were not found to be implicated in the immune response of our patients