Osteomyelitis is a devastating disease caused by microbial infection of bone While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone In contrast, S aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis There have also been major advances in our understanding of the immune proteome against S aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease Here, we review these recent advances and highlight translational opportunities towards a cure

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Evolving concepts in bone infection: redefining "biofilm", "acute vs. chronic osteomyelitis", "the immune proteome" and "local antibiotic therapy".

Hydrodynamics and surface properties influence biofilm proliferation.

Antimicrobial peptides constitute one of the most promising alternatives to antibiotics since they could be used to treat bacterial infections, especially those caused by multidrug-resistant pathogens. Many antimicrobial peptides, with various activity spectra and mechanisms of actions, have been described. This review focuses on their use against ESKAPE bacteria, especially in biofilm treatments, their synergistic activity, and their application as prophylactic agents. Limitations and challenges restricting therapeutic applications are highlighted, and solutions for each challenge are evaluated to analyze whether antimicrobial peptides could replace antibiotics in the near future.

Antimicrobial Peptides: A Potent Alternative to Antibiotics.

It is well established that the gut microbiota plays an important role in host health and is perturbed by several factors including antibiotics. Antibiotic‐induced changes in microbial composition can have a negative impact on host health including reduced microbial diversity, changes in functional attributes of the microbiota, formation, and selection of antibiotic‐resistant strains making hosts more susceptible to infection with pathogens such as Clostridioides difficile. Antibiotic resistance is a global crisis and the increased use of antibiotics over time warrants investigation into its effects on microbiota and health. In this review, we discuss the adverse effects of antibiotics on the gut microbiota and thus host health, and suggest alternative approaches to antibiotic use.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/mbo3.1260

Impact of antibiotics on the human microbiome and consequences for host health

Biofilm-mediated bioremediation is a powerful tool for the removal of environmental pollutants

Bacterial biofilms are complex surface attached communities of bacteria held together by self-produced polymer matrixs mainly composed of polysaccharides, secreted proteins, and extracellular DNAs. Bacterial biofilm formation is a complex process and can be described in five main phases: (i) reversible attachment phase, where bacteria non-specifically attach to surfaces; (ii) irreversible attachment phase, which involves interaction between bacterial cells and a surface using bacterial adhesins such as fimbriae and lipopolysaccharide (LPS); (iii) production of extracellular polymeric substances (EPS) by the resident bacterial cells; (iv) biofilm maturation phase, in which bacterial cells synthesize and release signaling molecules to sense the presence of each other, conducing to the formation of microcolony and maturation of biofilms; and (v) dispersal/detachment phase, where the bacterial cells depart biofilms and comeback to independent planktonic lifestyle. Biofilm formation is detrimental in healthcare, drinking water distribution systems, food, and marine industries, etc. As a result, current studies have been focused toward control and prevention of biofilms. In an effort to get rid of harmful biofilms, various techniques and approaches have been employed that interfere with bacterial attachment, bacterial communication systems (quorum sensing, QS), and biofilm matrixs. Biofilms, however, also offer beneficial roles in a variety of fields including applications in plant protection, bioremediation, wastewater treatment, and corrosion inhibition amongst others. Development of beneficial biofilms can be promoted through manipulation of adhesion surfaces, QS and environmental conditions. This review describes the events involved in bacterial biofilm formation, lists the negative and positive aspects associated with bacterial biofilms, elaborates the main strategies currently used to regulate establishment of harmful bacterial biofilms as well as certain strategies employed to encourage formation of beneficial bacterial biofilms, and highlights the future perspectives of bacterial biofilms.

/pdf/beyond-risk-bacterial-biofilms-and-their-regulating-4xnboj91j5.pdf

Beyond Risk: Bacterial Biofilms and Their Regulating Approaches.

Insect and mite pests are damaging stressors that are threatening the cultivation of tea plants, which result in enormous crop loss. Over the years, the effectiveness of synthetic pesticides has allowed for its prominent application as a control strategy. However, the adverse effects of synthetic pesticides in terms of pesticide residue, environmental contamination and insect pest resistance have necessitated the need for alternative strategies. Meanwhile, microbial pesticides have been applied to tackle the damaging activities of the insect and mite pests of tea plants, and their performances were scientifically adjudged appreciable and environmental friendly. Herein, entomopathogenic microbes that were effective against tea geometrid (Ectropis obliqua Prout), tea green leafhopper (Empoasca onukii Matsuda), paraguay tea ampul (Gyropsylla spegazziniana), tea mosquito bug (Helopeltis theivora Waterhouse) and red spider mite (Oligonychus coffea Nietner) have been reviewed. The current findings revealed that microbial pesticides were effective and showed promising performances against these pests. Overall, this review has provided the basic and integrative information on the integrated pest management (IPM) tool(s) that can be utilized towards successful control of the aforementioned insect and mite pests.

Ecologically controlling insect and mite pests of tea plants with microbial pesticides: a review

Thuricin 4AJ1, produced by Bacillus thuringiensis strain 4AJ1, showed inhibition activity against Bacillus cereus 0938 and ATCC 10987. It began to appear in the stationary phase and reached its maximum activity level of 209.958 U at 18 h against B. cereus 0938 and 285.689 U at 24 h against B. cereus ATCC 10987. Tricine–SDS-PAGE results showed that the partly purified thuricin 4AJ1 was about 6.5 kDa. The molecular weights of the known B. thuringiensis bacteriocins and the ones obtained by the two mainstream websites for predicting bacteriocins were inconsistent with the size of the thuricin 4AJ1, indicating that the bacteriocin obtained in this study may have a novel structure. Based on the biochemical properties, the thuricin 4AJ1 activities increased after treatment with proteinase K and lipase II, and were not affected by a-amylase, catalase, α-chymotrypsin VII and α-chymotrypsin II. It was heat tolerant, being active up to 90o C. In the pH 3–10 range, it maintained most of its activity. Finally, the sensitivity of the strain 4AJ1 to commonly used antibiotics was tested. In view of its stability and antibacterial activity, thuricin 4AJ1 may be applied as a food biopreservative.

Yachong Guo

Papers

Beyond Risk: Bacterial Biofilms and Their Regulating Approaches.

Ecologically controlling insect and mite pests of tea plants with microbial pesticides: a review

Identification and partial purification of thuricin 4AJ1 produced by Bacillus thuringiensis