Surfactin variants mediate species-specific biofilm formation and root colonization in Bacillus.

Cyclic lipopeptides (cLP) and especially surfactins produced by Bacillus spp. trigger biofilm formation and root colonization and are crucial for biocontrol activity and systemic resistance in plants. Bacillus atrophaeus 176s isolated from the moss Tortella tortuosa produces the cLP fengycins, iturins and surfactins, possesses antifungal activities and can protect tomato, lettuce and sugar beet against Rhizoctonia solani infection. In B. atrophaeus we identified for the first time the variant surfactin C, which differs from surfactin A produced by B. subtilis and B. amyloliquefaciens by an isoleucine instead of a leucine at position 7 of the lipopeptide backbone. The analysis of the complete surfactin gene clusters revealed that the dissimilarity is encoded in the adenylation domain of srfC and show that surfactin variations are distributed in a species-specific manner in bacilli. We demonstrate that the surfactin A and C with subtle structural differences have varying signal strengths on biofilm formation and root colonization and act specifically on the respective producing strain. This became evident as biofilm formation and root colonization but not swarming motility in surfactin biosynthesis mutants was restored differentially in the presence of exogenously supplemented cognate and non-cognate surfactin variants.

Pre-exposure prophylaxis for HIV with oral tenofovir disoproxil fumarate/emtricitabine in men who have sex with men: Slovenian national demonstration project.

Prevalence of HIV in Slovenia is low, and men who have sex with men (MSM) have the highest risk for infection. Rates of enrolment into HIV care, initiation of antiretroviral therapy and reaching an undetectable viral load in HIV-infected patients are very high. Prevention of HIV infection for MSM with PrEP is not formally available in Slovenia. The aim of this study was to demonstrate possible implementation of PrEP in Slovenia. Sixty-nine (n = 69) MSM with increased risk for HIV received PrEP with oral tenofovir disproxil fumarate /emtricitabine and acquisition were followed for a mean of 566.6 days. They had 71 episodes of STIs (incidence 61.7 per 100 person-years). No one got acquired HIV infection. Estimated glomerular filtration rate (EGFR) was significantly lower 4 (p = 0.014) and 19 (p = 0.021) months after inclusion; however, there was no clinically significant renal failure (mean EGFR 110-115 mL/min). Self-reported body weight significantly increased after 7 months (p < 0.05). Overall EGFR and self-reported body weight did not change significantly. No significant change in adherence (overall mean 81.0%; 95% CI 77.5%-84.6%; p = 0.728), condom use (p = 0.077) and number of sexual partners (overall mean 2.36 per 30 days; 95% CI 2.06 to 2.65; p = 0.235) was found throughout the study. Participants reported 110 graded adverse effects (AE), 104 (94.5%) grade 1-2 and 6 (5.5%) grade 3-4. No participant discontinued PrEP due to AE. The study showed successful implementation of PrEP among MSM at high risk for HIV infection in Slovenia. Based on the results of our study, PrEP should be formally available in Slovenia.