Netilmicin (NTM) is one of the first-line drugs for lower respiratory tract infections (LRTI) therapy, but its nephrotoxicity and ototoxicity caused by intravenous injection restrict its clinical application. Dry powder inhalation (DPI) is a popular local drug delivery system that is introduced as a solution. Due to the nature of NTM hygroscopicity that hinders its direct use through DPI, in this study, L-leucine (LL) was added into NTM dry powder to reduce its moisture absorption rate and improve its aerosolization performance. NTM DPIs were prepared using spray-drying with different LL proportions. The particle size, density, morphology, crystallinity, water content, hygroscopicity, antibacterial activity, in vitro aerosolization performance, and stability of each formulation were characterized. NTM DPIs were suitable for inhalation and amorphous with a corrugated surface. The analysis indicated that the water content and hygroscopicity were decreased with the addition of LL, whilst the antibacterial activity of NTM was maintained. The optimal formulation ND₂ (NTM:LL = 30:1) showed high fine particle fraction values (85.14 ± 8.97%), which was 2.78-fold those of ND₀ (100% NTM). It was stable after storage at 40 ± 2 °C, 75 ± 5% relative humidity (RH). The additional LL in NTM DPI successfully reduced the hygroscopicity and improved the aerosolization performance. NTM DPIs were proved to be a feasible and desirable approach for the treatment of LRTI.

Hemoplasmas belong to Mycoplasmataceae (Mollicutes: Mycoplasmatales) and are able to infect a broad range of mammalian species. We investigated prevalence of hemotropic mycoplasma species in pig farms in the region of Zhejiang by a PCR scheme using universal primers targeting 16S rRNA and RNase P RNA gene (rnpB). Representative positive samples from different farms were selected for sequencing of 16S rRNA and the 219bp rnpB gene fragments for phylogenetic analysis. Sequencing analysis of PCR products from first samples identified a novel hemoplasma species present in several pig farms in the region with highest nucleotide identity of 92% to Candidatus Mycoplasma turicensis. A duplex PCR assay was then designed for differential detection of the novel hemoplasma from Mycoplasma parvum/M. suis in field samples. Of 324 blood samples from clinically healthy pigs, 26.5% was positive for this novel hemoplasma species and 50% positive for M. suis/M. parvum, indicating that the novel hemotropic mycoplasma species were of considerably high prevalence in Zhejiang province, China.

The delayed healing of infected post-operative wounds has turned into a worldwide medical problem. In the clinical treatment, effective bacterial clearance and promoted wound healing were considered as two crucial aspects. However, the effect of current dressings with antibacterial activity was limited due to the declined efficacy against antibiotic-resistant bacteria, and poor mechanical property during skin extension and compression movement. In this project, a lyotropic liquid crystal (LLC)-based bacteria-resistant and self-healing spray dressing loaded with ε-polylysine (PLL) was designed. Owing to the unique antibacterial mechanism, PLL was expected to kill antibiotic-resistant bacteria efficiently, even the “superbug” methicillin-resistant Staphylococcus aureus (MRSA). The cubic cells of LLC were applied to encapsulate PLL to improve its stability and induce a sustained release, further realizing a long-term antibacterial effect. Meanwhile, the LLC precursor (LLCP) could extend to the irregular edges of the wound, and spontaneously transited to a cubic phase gel once exposed to physiological fluid. This 3D structure was also endowed with mechanically responsive viscoelasticity that formed a robust and flexible defense for wounds. An excellent antibacterial activity with more than 99% MRSA killed in 3 h was demonstrated by a killing kinetics study. The long-term effect was also proved by measuring the bacteriostatic circle test within 48 h. In addition, the unique sol–gel phase transition behavior and superior self-healing capacity of PLL-LLCP was verified with the rheological study and self-recoverable conformal deformation test in vivo. In the infected post-operative wound model, satisfactory bacterial clearance and prominent wound healing promotion were realized by PLL-LLCP, with the survival of the bacteria at lower than 0.1% and the wound closure at higher than 90%. Thus, PLL-LLCP was believed to be an excellent candidate for the therapy of infected post-operative wounds.