THU0281 EXPLORING THE GENETIC DIVERSITY OF STAPHYLOCOCCUS AUREUS IN PATIENTS AFFECTED BY SYSTEMIC LUPUS ERYTHEMATOSUS: ASSOCIATION WITH DISEASE-RELATED FEATURES AND ACTIVITY

Background:

Infective factors play a central role in autoimmune diseases pathogenesis. It is possible to speculate that the host genotype could interact with genetic background of infective agents. We previously evaluated a large SLE cohort, observing the association between theS. Aureus(SA) carriage status and presence of a more active disease in terms of autoantibodies positivity.

Objectives:

We evaluated epidemiological, molecular characterization, genetic diversity and evolution of SA isolated from SLE patients by means of phylogenetic analysis.

Methods:

Consecutive SLE patients (ACR 1997 criteria) were enrolled: clinical/laboratory data were collected and nasal swab for SA identification was performed. On the basis of translation elongation factor (tuf) gene, a phylogenetic analysis was performed to investigate phylogenetic relationships and to assess significant clades in patients with persistent carriage status (nasal swab positive in two consecutive evaluation, performed 1 week apart). The first dataset was composed by seven SA tuf gene isolated from non-SLE individuals from different countries (downloaded from the GenBank database,https://www.ncbi.nlm.nih.gov/nucleotide/) and tuf gene SA collected from SLE patients enrolled in the present study.

Results:

We enrolled 118 patients (M/F 10/198; median age 45.5 years, IQR 13,2; median disease duration 120 months, IQR 144). Skin involvement is the most frequent disease manifestation (86 patients, 72.9%), followed by joint involvement (78 patients, 66.1%). Twenty-four patients (20.3%) were SA carriers (SA+), three of them resulted MRSA. SA+ patients showed a significantly higher prevalence of joint involvement (79.2%versus62.7%, P=0.01) and anti-dsDNA positivity (75.0%versus55.3%, P=0.004). Moreover, SA+ SLE showed a more active disease, in terms of SLEDAI-2k values [SA+: median 2 (IQR 3.75)versusSA-: median 0 (IQR 2), P=0.04). The phylogenetic analysis has been restricted on the 21 non-MRSA SA+ patients. The maximum likelihood phylogenetic tree of the first dataset revealed a statistically supported larger clade (A, N=17) and a smaller one (B, N=4; figure 1A). SLE patients located in the clade A showed a significantly higher prevalence of joint involvement (88.2%) in comparison with clade B (50.0%, P<0.0001) and SA- (62.7%, P<0.0001, figure 2B). Moreover, haematological manifestations were significantly more frequent in clade A patients (64.7%) compared with B (50.0%, P=0.004, figure 2C).

Conclusion:

The results of the present study confirmed the association between SA carriage status and disease activity, in terms of SLEDAI-2k values and anti-dsDNA positivity. The phylogenetic analysis ontufgene show a clustering ofSA+patients in two major clade (A and B). Interestingly thetufgenotype of clade A is significantly associated with a specific disease phenotype, characterized by joint involvement and positivity for anti-dsDNA. These findings support the hypothesis that bacterial genetic variants may be associated with specific disease features.

References:

[1]Rigante et al. Int J Mol Sci. 2015;

[2]Wertheim et al Lancet Infect Dis. 2005;

[3]Conti et al Arthritis Res Ther 2016;

[4]Tong et al Clin Microbiol Rev. 2015;

[5]Rhee et al Infect Control Hosp Epidemiol. 2015

Disclosure of Interests:

Giulio Olivieri: None declared, Fulvia Ceccarelli: None declared, Alessandra Lo Presti: None declared, silvia angeletti: None declared, Carlo Perricone: None declared, Giancarlo Iaiani: None declared, Lucia De Florio: None declared, francesca antonelli: None declared, Luigino Amori: None declared, Cristina Garufi: None declared, Francesca Romana Spinelli Grant/research support from: Pfizer, Speakers bureau: Lilly, BMS, Celgene, cristiano Alessandri: None declared, Guido Valesini: None declared, Massimo Cicozzi: None declared, Fabrizio Conti Speakers bureau: BMS, Lilly, Abbvie, Pfizer, Sanofi

Effect of risedronate in osteoporotic HIV males, according to gonadal status: a pilot study

The aim of the study was to evaluate the effect of risedronate on bone mineral density (BMD) and bone turnover markers in HIV-infected osteoporotic males, according to their gonadal status. HIV patients were followed up for 24 months and divided into two groups: patients with osteoporosis or osteopenia with fractures (group A, n = 20) and those without (group B, n = 21). Group A and B were further divided according to the presence of reduced androgenizations. Both groups were treated with cholecalciferol 800 I.U. and calcium (Ca) 1,000 mg orally every day for the first 12 months. Risedronate 75 mg for two consecutive days a month orally was then added in group A, for another 12 months. Group B continued treatment with Ca and vitamin D. Every 6 months each patient underwent biochemical evaluation, and BMD measurement. A significant increase in lumbar BMD was observed in HIV males with adequate androgenization after 12 months of risedronate treatment in group A together with a reduction of bone turnover markers. BMD remained stable with a concomitant significant slight reduction of bone turnover markers in group B. Risedronate increased BMD and reduced bone turnover markers to a greater extent in patients with adequate androgenization compared to osteoporotic HIV males with symptomatic hypoandrogenization.