Degradable antimicrobial polycarbonates with unexpected activity and selectivity for treating multidrug-resistant Klebsiella pneumoniae lung infection in mice.

Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections around the world, with attendant high rates of morbidity and mortality. Progressive reduction in potency of antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance provides the motivation to develop drug candidates targeting MDR K. pneumoniae. We recently reported degradable broad-spectrum antimicrobial guanidinium-functionalized polycarbonates with unique antimicrobial mechanism - membrane translocation followed by precipitation of cytosolic materials. These polymers exhibited high potency against bacteria with negligible toxicity. The polymer with ethyl spacer between the quanidinium group and the polymer backbone (pEt_20) showed excellent in vivo efficacy for treating MDR K. pneumoniae-caused peritonitis in mice. In this study, the structures of the polymers were optimized for the treatment of MDR Klebsiella pneumoniae lung infection. Specifically, in vitro antimicrobial activity and selectivity of guanidinium-functionalized polycarbonates containing the same number of guanidinium groups but of a shorter chain length and a structural analogue containing a thiouronium moiety as the pendent cationic group were evaluated. The polymers with optimal compositions and varying hydrophobicity were assessed against 25 clinically isolated K. pneumonia strains for antimicrobial activity and killing kinetics. The results showed that the polymers killed the bacteria more efficiently than clinically used antibiotics, and repeated use of the polymers did not cause drug resistance in K. pneumonia. Particularly, the polymer with butyl spacer (pBut_20) self-assembled into micelles at high concentrations, where the hydrophobic component was shielded in the micellar core, preventing interacting with mammalian cells. A subtle change in the hydrophobicity increased the antimicrobial activity while reducing in vivo toxicity. The in vivo efficacy studies showed that pBut_20 alleviated K. pneumonia lung infection without inducing damage to major organs. Taken together, pBut_20 is promising for treating MDR Klebsiella pneumoniae lung infection in vivo. STATEMENT OF SIGNIFICANCE: Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections, with attendant high rates of morbidity and mortality. The progressive reduction in antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance rates provides the motivation to develop drug candidates. In this study, we report a degradable guanidinium-functionalized polycarbonate with unexpected antimicrobial activity and selectivity towards MDR Klebsiella pneumoniae. A subtle change in polymer hydrophobicity increases antimicrobial activity while reducing in vivo toxicity due to self-assembly at high concentrations. The polymer with optimal composition alleviates Klebsiella pneumonia lung infection without inducing damage to major organs. The polymer is promising for treating MDR Klebsiella pneumoniae lung infection in vivo.

Mechanistic research holds promise for bacterial vaccines and phage therapies for Pseudomonas aeruginosa.

Vaccines for Pseudomonas aeruginosa have been of longstanding interest to immunologists, bacteriologists, and clinicians, due to the widespread prevalence of hospital-acquired infection. As P. aeruginosa becomes increasingly antibiotic resistant, there is a dire need for novel treatments and preventive vaccines. Despite intense efforts, there currently remains no vaccine on the market to combat this dangerous pathogen. This article summarizes current and past vaccines under development that target various constituents of P. aeruginosa. Targeting lipopolysaccharides and O-antigens have shown some promise in preventing infection. Recombinant flagella and pili that target TLR5 have been utilized to combat P. aeruginosa by blocking its motility and adhesion. The type 3 secretion system components, such as needle-like structure PcrV or exotoxin PopB, are also potential vaccine targets. Outer membrane proteins including OprF and OprI are newer representatives of vaccine candidates. Live attenuated vaccines are a focal point in this review, and are also considered for novel vaccines. In addition, phage therapy is revived as an effective option for treating refractory infections after failure with antibiotic treatment. Many of the aforementioned vaccines act on a single target, thus lacking a broad range of protection. Recent studies have shown that mixtures of vaccines and combination approaches may significantly augment immunogenicity, thereby increasing their preventive and therapeutic potential.

A macromolecular approach to eradicate multidrug resistant bacterial infections while mitigating drug resistance onset.

Polymyxins remain the last line treatment for multidrug-resistant (MDR) infections. As polymyxins resistance emerges, there is an urgent need to develop effective antimicrobial agents capable of mitigating MDR. Here, we report biodegradable guanidinium-functionalized polycarbonates with a distinctive mechanism that does not induce drug resistance. Unlike conventional antibiotics, repeated use of the polymers does not lead to drug resistance. Transcriptomic analysis of bacteria further supports development of resistance to antibiotics but not to the macromolecules after 30 treatments. Importantly, high in vivo treatment efficacy of the macromolecules is achieved in MDR A. baumannii-, E. coli-, K. pneumoniae-, methicillin-resistant S. aureus-, cecal ligation and puncture-induced polymicrobial peritonitis, and P. aeruginosa lung infection mouse models while remaining non-toxic (e.g., therapeutic index-ED50/LD50: 1473 for A. baumannii infection). These biodegradable synthetic macromolecules have been demonstrated to have broad spectrum in vivo antimicrobial activity, and have excellent potential as systemic antimicrobials against MDR infections.

Graphene oxide as an efficient antimicrobial nanomaterial for eradicating multi-drug resistant bacteria in vitro and in vivo.

Graphene is a novel two-dimensional nanomaterial with a growing number of practical applications across numerous fields. In this work, we explored potential biomedical applications of graphene oxide (GO) by systematically studying antibacterial capacity of GO in both macrophages and animal models. Three types of bacteria, including Klebsiella pneumoniae (Kp), Escherichia coli (E. coli) and P. aeruginosa (Pa) were used for in vitro study. Kp was also selected as a representative multidrug resistant (MDR) bacterium for in vivo study. In in vitro study, GO effectively eradicated Kp in agar dishes and thus protected alveolar macrophages (AM) from Kp infection in the culture. In the in vivo evaluation, GO were introduced intranasally into mouse lungs followed by testing organ tissue damage including lung, liver, spleen, and kidneys, polymorphonuclear neutrophil (PMN) penetration, bacterial dissemination, and mortality in Kp-infected mice. We found that GO can prohibit the growth and spread of Kp both in vitro and in vivo, resulting in significantly increased cell survival rate, less tissue injury, subdued inflammatory response, and prolonged mice survival. These findings indicate that GO could be a promising biomaterial for effectively controlling MDR pathogens.

Early sitting, standing, and walking in conjunction with contemporary Bobath approach for stroke patients with severe motor deficit.

BACKGROUND: The commonly used therapeutic approach, the contemporary Bobath approach (CBA), is not sufficient to restore independent locomotion for individuals with severe motor deficit (SMD) after stroke. Therefore, we propose that the early sitting, standing, and walking in conjunction with the CBA (ECBA) be used to treat individuals with SMD after stroke. OBJECTIVE: To investigate whether ECBA may enhance mobility and balance in subjects with SMD after stroke. METHODS: Thirty-three men and 15 women, aged 60 to 74 years, with SMD after stroke were recruited for the study. CBA or ECBA was performed with the subjects 5 times per week in 50-minute sessions for 8 weeks. The Stroke Rehabilitation Assessment of Movement (STREAM) and the Berg Balance Scale were implemented before treatment and at 4 and 8 weeks after treatment, respectively. RESULTS: The STREAM scores indicated that ECBA was more efficient than the CBA intervention for lower extremity mobility, F(1, 46) = 24.0, P < .001, and basic mobility, F(1, 46) = 102.6, P < .001. Overall STREAM scores were higher in the ECBA group, F(1, 46) =24.1, P < .001, after 8 weeks of therapy. Balance scores of the ECBA subjects were higher than those of the CBA subjects after 8 weeks of therapy, F(1, 46) = 73.1, P < .001. However, there was no difference in upper extremity mobility between the 2 groups. CONCLUSION: ECBA is a valuable intervention to improve lower extremity mobility, basic mobility, and balance ability for individuals with SMD after stroke.

[Efficacy comparison of different stimulation therapies for periarthritis of shoulder].

OBJECTIVE: To compare clinical efficacy differences among electroacupuncture (EA), transcutaneous electrical nerve stimulation (TENS) therapy and acupoint massage (AM) on periarthritis of shoulder. METHODS: One hundred and twenty cases were randomly divided into an EA group, a TENS group and an AM group, 40 cases in each one. The selection of acupoints in the three groups were all the same, which were Jianqian (Extra), Xiabai (LU 4), Jianyu (LI 15), Binao (LI 14), Jianliao (TE 14), Naohui (TE 13), Xiaohai (SI 8) and Houxi (SI 3). EA was applied in the EA group with dense-disperse wave for 30 min, TENS therapy with dense-disperse wave for 30 min in the TENS group and AM combined with mobilization manipulation of Tuina on the shoulder in the AM group. All of the treatment was given once a day, six times a week and totally 4 weeks were required. The score of visual analogue scale (VAS) and improvement of shoulder joint activities in the three groups before and after the treatment were observed. RESULTS: After the treatment, the VAS score and activities of shoulder joint were all improved in the three groups (all P < 0.001) and AM group had more obvious improvement than TENS group and EA group (all P < 0.05). The effective and curative rate was 61.50 (24/39) in the AM group, which was superior to 42.9% (15/35) in the EA group and 44.4% (16/36) in the TENS group (both P < 0.05). The effective and curative rate of shoulder joint activities in the AM group was 61.5% (24/39), which was superior to 48.6% (17/35) in the EA group and 44.4% (16/36) in the TENS group (both P < 0.05). CONCLUSION: The acupoint massage has obvious clinical efficacy on periarthritis of shoulder, which could effectively relieve the pain and improve activities of shoulder joint, and it is superior to EA and TENS therapy.