Gastrointestinal Dynamics of Non-Encapsulated and Microencapsulated Salmonella Bacteriophages in Broiler Production

Bacteriophage therapy is being considered as a promising tool to control Salmonella in poultry. Nevertheless, changes in gastrointestinal tract environmental conditions throughout the production cycle could compromise the efficacy of phages administered orally. The main objectives of this study were to assess the optimal timing of the phage administration over a 42-day production cycle and to compare microencapsulated and non-encapsulated phages and the spatial and temporal dynamics of the phage delivery along the gastrointestinal tract. Phage FGS011 was encapsulated in the pH-responsive polymer Eudragit® L100 using the process of spray drying. At different weeks of the chicken rearing period, 15 broilers were divided into three groups. Over a period of 24 h, group 1 received non-encapsulated phages (delivered through drinking water), group 2 received microencapsulated phages (incorporated in animal feed), and group 3 did not receive any phages. Microencapsulation was shown to enable efficient delivery of the bacteriophages to the animal gut and cecum throughout the animal rearing period. During the six weeks of application, the crop displayed the highest phage concentration for both phage delivery methods. The L100 based encapsulation offered significant protection to the phages from the harsh environmental conditions in the PV-Gizzard (not seen with phages administered in drinking water) which may help in the delivery of high phage doses to the cecum. Future Salmonella challenge studies are necessary to demonstrate the benefits of microencapsulation of phages using L100 formulation on phage therapy in field studies during the rearing period.

The characteristic and potential therapeutic effect of isolated multidrug-resistant Acinetobacter baumannii lytic phage

Background Widespread misuse of antibiotics caused bacterial resistance increasingly become a serious threat. Bacteriophage therapy promises alternative treatment strategies for combatting drug-resistant bacterial infections. In this study, we isolated and characterized a novel, potent lytic bacteriophage against multi-drug resistant (MDR) Acinetobacter baumannii and described the lytic capability and endolysin activity of the phage to evaluate the potential in phage therapy. Methods A novel phage, pIsf-AB02, was isolated from hospital sewage. The morphological analysis, its host range, growth characteristics, stability under various conditions, genomic restriction pattern were systematically investigated. The protein pattern of the phage was analyzed, and the endolysin activity of the phage was determined under the non-denaturing condition on SDS-PAGE. The optimal lytic titer of phage was assessed by co-culture of the phage with clinical MDR A. baumannii isolates. Finally, HeLa cells were used to examine the safety of the phage. Results The morphological analysis revealed that the pIsf-AB02 phage displays morphology resembling the Myoviridae family. It can quickly destroy 56.3% (27/48) of clinical MDR A. baumannii isolates. This virulent phage could decrease the bacterial host cells (from 108 CFU/ml to 103 CFU/ml) in 30 min. The optimum stability of the phage was observed at 37 °C. pH 7 is the most suitable condition to maintain phage stability. The 15 kDa protein encoded by pIsf-AB02 was detected to have endolysin activity. pIsf-AB02 did not show cytotoxicity to HeLa cells, and it can save HeLa cells from A. baumannii infection. Conclusion In this study, we isolated a novel lytic MDR A. baumannii bacteriophage, pIsf-AB02. This phage showed suitable stability at different temperatures and pHs, and demonstrated potent in vitro endolysin activity. pIsf-AB02 may be a good candidate as a therapeutic agent to control nosocomial infections caused by MDR A. baumannii.

Biological Therapy on Infected Traumatic Wounds: A Case-Control Study

Background:Traumatic wound is a great challenging issue to surgeons, because of large in size, heavily contaminated, infected and unscenic. Infection proceeded to progressive tissue necrosis, septicemia, organ failure or even death. Majority has polymicrobial infections. Bacteriohage therapy will have revolutionized in the treatment of wound. The present study was planned to evaluate the efficacy of topical bacteriophage therapy on large traumatic wounds in comparison with conventional therapy. Methods:The Study conducted from Sept. 2018 to July 2020. Samples between 12- 60 years was taken into study. Customized bacteriophage applied over the wound after serial debridement in case and conventional dressing in control. Fifty four wounded person met the clinical inclusion criteria; 27 in each group. Wound swab and tissue biopsy was taken for bacterial isolation. Isolated specific phage was applied over the wound on alternate day till the wound become sterile and fit for further definitive management. Results: A significant and rapid improvement was observed in wound healing in cases then control group. Average number of day required for complete granulation of wound and attaining sterility was half in cases then control. The hospital stay of the patients on BT was half (20days) than those on CT (40 days). The financial analysis also favours the BT over CT as only 1/third expenditure incurred in BT group as compared to CT Conclusion:Topical Bacteriophage therapy is efficient, effective to clearing the infection in shorter length of time and cost effective for infected traumatic wounds as compared to conventional dressing.

Preclinical Assessment of Bacteriophage Therapy against Experimental Acinetobacter baumannii Lung Infection

Respiratory infections caused by multidrug-resistant Acinetobacter baumannii are difficult to treat and associated with high mortality among critically ill hospitalized patients. Bacteriophages (phages) eliminate pathogens with high host specificity and efficacy. However, the lack of appropriate preclinical experimental models hampers the progress of clinical development of phages as therapeutic agents. Therefore, we tested the efficacy of a purified lytic phage, vB_AbaM_Acibel004, against multidrug-resistant A. baumannii clinical isolate RUH 2037 infection in immunocompetent mice and a human lung tissue model. Sham- and A. baumannii-infected mice received a single-dose of phage or buffer via intratracheal aerosolization. Group-specific differences in bacterial burden, immune and clinical responses were compared. Phage-treated mice not only recovered faster from infection-associated hypothermia but also had lower pulmonary bacterial burden, lower lung permeability, and cytokine release. Histopathological examination revealed less inflammation with unaffected inflammatory cellular recruitment. No phage-specific adverse events were noted. Additionally, the bactericidal effect of the purified phage on A. baumannii was confirmed after single-dose treatment in an ex vivo human lung infection model. Taken together, our data suggest that the investigated phage has significant potential to treat multidrug-resistant A. baumannii infections and further support the development of appropriate methods for preclinical evaluation of antibacterial efficacy of phages.

Classic vs. Novel Antibacterial Approaches for Eradicating Dental Biofilm as Adjunct to Periodontal Debridement: An Evidence-Based Overview

Periodontitis is a multifactorial chronic inflammatory disease that affects tooth-supporting soft/hard tissues of the dentition. The dental plaque biofilm is considered as a primary etiological factor in susceptible patients; however, other factors contribute to progression, such as diabetes and smoking. Current management utilizes mechanical biofilm removal as the gold standard of treatment. Antibacterial agents might be indicated in certain conditions as an adjunct to this mechanical approach. However, in view of the growing concern about bacterial resistance, alternative approaches have been investigated. Currently, a range of antimicrobial agents and protocols have been used in clinical management, but these remain largely non-validated. This review aimed to evaluate the efficacy of adjunctive antibiotic use in periodontal management and to compare them to recently suggested alternatives. Evidence from in vitro, observational and clinical trial studies suggests efficacy in the use of adjunctive antimicrobials in patients with grade C periodontitis of young age or where the associated risk factors are inconsistent with the amount of bone loss present. Meanwhile, alternative approaches such as photodynamic therapy, bacteriophage therapy and probiotics showed limited supportive evidence, and more studies are warranted to validate their efficiency.

Evaluation of Three Isolation Experiments for Campylobacter Bacteriophages from Chicken Skin: A Comparative Study

Background: Campylobacter strains are of the leading pathogens causing bacterial gastroenteritis, whose infections are generally considered to be one of the most common foodborne illnesses of animal origin. The etiology of this infection often goes back to eating contaminated raw meat or infected poultry. The bacteria are present in abundance in chicken skin. The use of appropriate bacteriophages is one of the most effective experiments in eliminating Campylobacter strains. Phage therapy refers to the use of bacteriophages to treat bacterial infections. Aim: Accordingly, the present study aimed to compare three experiments of bacteriophage isolation in chicken skin. Experiments: Thus, 15 samples of chicken skin were collected from five different fresh chicken suppliers in Ghaemshahr, Iran. The samples were transported to the laboratory aseptically in the vicinity of ice, and then cultured in blood agar medium, and the isolates were identified by various tests including gram staining, catalase and oxidase tests. Results: The results were compared before and after three bacteriophage isolation experiments. Out of 15 chicken skin samples tested in all three experiments, 6 (40%) strains were identified in the first experiment, 8 (53.4%) strains in the second experiment and 12 (20%) strains in the third experiment after bacteriophage therapy. Conclusion: The bacteriophage isolation experiments alone or in combination with other intervention strategies are recommended as promising tools for greater food safety. These experiments can be useful to increase food safety and reduce the risk of infection in humans through the consumption of potentially infected edible parts of chicken. According to the results of this study, among the three proposed experiments, the experiment of chicken skin enrichment in Bolton selective media containing target isolates was the most efficient approach, which showed a high limit of detection at low concentrations and the highest rate of phage recovery. This can be a more reliable way to isolate the Campylobacter bacteriophages and eliminate the Campylobacter strains.

Bacteriophage Therapy for the Prevention and Treatment of Fracture-Related Infection Caused by Staphylococcus aureus: a Preclinical Study

Because of the growing spread of antimicrobial resistance, the use of alternative prevention and treatment strategies is gaining interest. Although the therapeutic potential of bacteriophages has been demonstrated in a number of case reports and series over the past decade, many unanswered questions remain regarding the optimal application protocol.

Bacteriophages for the Treatment of Graft Infections in Cardiovascular Medicine

Bacterial infections of vascular grafts represent a major burden in cardiovascular medicine, which is related to an increase in morbidity and mortality. Different factors that are associated with this medical field such as patient frailty, biofilm formation, or immunosuppression negatively influence antibiotic treatment, inhibiting therapy success. Thus, further treatment strategies are required. Bacteriophage antibacterial properties were discovered 100 years ago, but the focus on antibiotics in Western medicine since the mid-20th century slowed the further development of bacteriophage therapy. Therefore, the experience and knowledge gained until then in bacteriophage mechanisms of action, handling, clinical uses, and limitations were largely lost. However, the parallel emergence of antimicrobial resistance and individualized medicine has provoked a radical reassessment of this approach and cardiovascular surgery is one area in which phages may play an important role to cope with this new scenario. In this context, bacteriophages might be applicable for both prophylactic and therapeutic use, serving as a stand-alone therapy or in combination with antibiotics. From another perspective, standardization of phage application is also required. The ideal surgical bacteriophage application method should be less invasive, enabling highly localized concentrations, and limiting bacteriophage distribution to the infection site during a prolonged time lapse. This review describes the latest reports of phage therapy in cardiovascular surgery and discusses options for their use in implant and vascular graft infections.

Evaluation of a pre-harvest bacteriophage therapy for control of Salmonella within bovine peripheral lymph nodes

A series of proof of concept studies were developed to determine if a commercial bacteriophage (phage) cocktail could be utilized for the mitigation of Salmonella in bovine peripheral lymph nodes (LN). The first objective sought to determine if exogenous phage could be isolated from the LN following administration. If successful, the second objective sought to determine if once in the LN, could the phage effectively reduce Salmonella . Salmonella Montevideo was inoculated intradermally in multiple sites and administrations, later followed by delivery of the phage cocktail subcutaneously in two injections around each of the right and left prescapular and subiliac LN. At the conclusion of each study, animals were euthanized and the popliteal and above LN examined. The first study was successful, in that transmission electron microscopy revealed the presence of phage in the LN of the treated cattle, that were identical to the strains in the cocktail. Concentrations of phage were increased ( P < 0.01) in the pre-scapular and subiliac LN in the phage-treated versus control cattle. Subsequent studies modified the protocols to increase Salmonella and phage concentrations within the LN. Overall concentrations of Salmonella were increased in the LN compared to the first study and phage treatment decreased ( P < 0.01) Salmonella in the some of the LN. Phage concentrations were numerically ( P = 0.12), but not statistically, increased in the treated cattle. The final study was modified, hypothesizing that a 48h post-mortem period prior to LN removal would facilitate phage/ Salmonella interaction, however, there were no differences ( P > 0.10) in Salmonella concentrations among treatments. Results demonstrated that Salmonella- specific phages administered to live cattle can translocate to the LN, however once in the LN they had limited to no effect on Salmonella within these nodes.