RESUMO
Bacterial infections have become increasingly difficult to treat due to the occurrence of antibiotic-resistant strains. A promising strategy to increase the efficacy of therapy is to combine antibacterials with agents that decrease pathogen virulence via the modulation of the quorum sensing (QS). Lactonases inhibit acylated homoserine lactone (AHL)-mediated QS in Gram-negative bacteria, including the leading nosocomial pathogen Pseudomonas aeruginosa. Here we describe the characteristics of heterologously expressed YtnP lactonase from Bacillus paralicheniformis ZP1 (YtnP-ZP1) isolated from agricultural soil using the culture enrichment method. Purified YtnP-ZP1 hydrolyzed different AHLs with preference to substrates with long acyl residues as evaluated in assays with biosensors and HPLC. The enzyme showed good thermostability and activity in a wide temperature range. YtnP-ZP1 in 50 µg mL-1 concentration reduced the amount of P. aeruginosa-produced long-chain AHLs by 85%, while it hydrolyzed 50% of short-chain AHLs. Incubation of P. aeruginosa PAO1 with YtnP-ZP1 reduced its swarming motility and elastolytic activity without bactericidal effect. YtnP-ZP1 caused the inhibition of biofilm formation and disintegration of mature biofilms in P. aeruginosa PAO1 and multiresistant clinical strain BR5H that was visualized by crystal violet staining. The treatment with YtnP-ZP1 in concentrations higher than 25 µg mL-1 improved the survival of P. aeruginosa PAO1-infected zebrafish (Danio rerio), rescuing 80% of embryos, while in combination with tobramycin or gentamicin survival rate increased to 100%. The treatment of P. aeruginosa PAO1 biofilms on infected zebrafish tail wounds with 50 µg mL-1 YtnP-ZP1 and 2 × MIC tobramycin led to infection clearing in 2 days. The extensive toxicity studies proved YtnP-ZP1 was non-toxic to human cells and zebrafish. In conclusion, novel YtnP-ZP1 lactonase with its effective anti-virulence activity could be used to increase the efficacy of clinically approved antibiotics in clearing both systemic and biofilm-associated P. aeruginosa infections.
RESUMO
AIM: To asses the prevalence and correlates of female sexual problems in a community sample in the Croatian capital of Zagreb. METHOD: The study was based on a self-administered postal survey of 1,170 women 20-60 years old, living in Zagreb. The return rate was 48% (n=547). Participants not sexually active in the last month (n=119), and those who self-identified as homosexual or bisexual (n=31), were excluded from the analyses. The final sample consisted of 384 women. The average age of participants was 38.2 years. Four categories of sexual problems were addressed: inhibited sexual desire, inhibited sexual arousal, inhibited orgasm, and sexual pain disorders. RESULTS: Of the heterosexual women sexually active in the last month, 33.8% experienced sexual problems, with inhibited orgasm being the most frequent problem. Comorbidity was recorded among 10.7% of the participants. Older age was positively related to inhibited desire (beta=0.11, P=0.05) and inhibited arousal (beta=0.25, P=0.002), whereas it was negatively related to inhibited orgasm and sexual pain disorders (beta=-3.73, P=0.001 and beta=-6.98, P=0.01, respectively). Length of relationship was positively related to inhibited desire (beta=1.17, P=0.016). Religious morality was positively related to inhibited desire, inhibited arousal, and sexual pain disorders (beta=0.43, P<0.001, beta=0.52, P=0.001, and beta=0.11, P=0.044, respectively). Intimate communication was negatively related to inhibited desire, inhibited arousal, and inhibited orgasm (beta=-2.18, P<0.001, beta=-2.67, P<0.001, and beta=-0.21, P=0.003, respectively); and body image was negatively related to inhibited arousal and sexual pain disorders (beta=-1.17, P=0.026 and beta=-0.38, P=0.042, respectively). CONCLUSION: Sexual health disturbances among urban Croatian women are frequent. Their prevalence calls for incorporating sexual health issues in the national public health agenda. Multifaceted character of sexual problems is important for adult sexuality education and counseling.