Objective: To investigate the antibacterial effect of selected lactic acid bacteria(LAB)biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus(MRSA)(S547).Methods: In this stu...Objective: To investigate the antibacterial effect of selected lactic acid bacteria(LAB)biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus(MRSA)(S547).Methods: In this study, biofilm-forming LAB were isolated from tairu and kefir. Isolate Y1 and isolate KF were selected based on their prominent inhibition against test pathogens(using spot-on-agar method and agar-well-diffusion assay) and efficient biofilm production(using tissue culture plate method). They were then identified as Lactobacillus casei(L. casei) Y1 and Lactobacillus plantarum(L. plantarum) KF, respectively using16 S r DNA gene sequencing. The influence of incubation time, temperature and aeration on the biofilm production of L. casei Y1 and L. plantarum KF was also investigated using tissue culture plate method. The inhibitory activity of both the selected LAB biofilms was evaluated against MRSA(Institute for Medical Research code: S547) using L. plantarum ATCC 8014 as the reference strain.Results: L. casei Y1 showed the highest reduction of MRSA biofilms, by 3.53 log at48 h while L. plantarum KF records the highest reduction of 2.64 log at 36 h. In inhibiting planktonic population of MRSA(S547), both L. casei Y1 and L. plantarum KF biofilms recorded their maximum reduction of 4.13 log and 3.41 log at 24 h, respectively. Despite their inhibitory effects being time-dependent, both LAB biofilms exhibited good potential in controlling the biofilm and planktonic population of MRSA(S547).Conclusions: The results from this study could highlight the importance of analysing biofilms of LAB to enhance their antibacterial efficacy. Preferably, these protective biofilms of LAB could also be a better alternative to control the formation of biofilms by pathogens such as MRSA.展开更多
This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine...This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to confirm the conjugation of the targeting ligand via the formation of amide bonds. Approximately 45% of VAN could be loaded into the aqueous cores, whereas 90% DAPT was detected using UV–vis spectrophotometry. In comparison to free drugs, the formulations controlled the release of drugs for > 72 h. Additionally, as demonstrated using CLSM and flow cytometry, the resulting formulation was capable of evading detection by macrophage cells. In comparison to free drugs, red blood cell membrane–DAPT–VAN liposomes, DAPT liposomes, and VAN liposomes reduced the MIC and significantly increased bacterial permeability, resulting in > 80% bacterial death within 4 h. Cytotoxicity tests were performed in vitro and in vivo on mammalian cells,in addition to hemolytic activity tests in human erythrocytes, wherein drugs loaded into the liposomes and RBCDVL exhibited low toxicity. Thus, the findings of this study provide insight about a dual antibiotic targeting strategy that utilizes liposomes and red blood cell membranes to deliver targeted drugs against MRSA.展开更多
Objective:To synthesize zinc oxide nanoparticles(ZnONPs)and evaluate their antibacterial and wound healing effects against wounds infected with methicillin-resistant Staphylococcus aureus(MRSA).Methods:ZnONPs were pre...Objective:To synthesize zinc oxide nanoparticles(ZnONPs)and evaluate their antibacterial and wound healing effects against wounds infected with methicillin-resistant Staphylococcus aureus(MRSA).Methods:ZnONPs were prepared by sol-gel method and characterized by X-ray diffraction(XRD)analysis and scanning electron microscopy(SEM).A total of 18 rabbits were divided into three groups:the ZnONPs group,the gentamicin group and the control group.A wound of 3 cm^(2) was inflicted on each rabbit and contaminated with MRSA inoculum.Treatment was started from the fourth day post-surgery.Wound healing,microbiological analysis,and histopathological analysis were performed to assess the efficacy of ZnONPs ointment.Results:XRD analysis confirmed the hexagonal wurtzite structure of the ZnONPs with an average crystallite size of 29.23 nm.SEM revealed discoid-shaped ZnONPs with a rough surface and an average size of 48.36 nm.Energy-dispersive X-ray analysis confirmed the purity of ZnONPs.Moreover,the particle size ranged from 100-700 nm with a high agglomeration trend.Treatment with ZnONPs promoted MRSA-infected wound healing.In addition,ZnONPs showed a good antibacterial effect as evidenced by a dose-dependent increase in the zone of inhibition.Conclusions:ZnONPs accelerate the healing of MRSA-infected wounds.Therefore,it can be explored for the treatment of MRSA infection.展开更多
Nasal colonization with pathogenic bacteria continues to present challenges for patients undergoing surgical procedures, and for the physicians that treat them. Even as molecular medicine produces ever faster and impr...Nasal colonization with pathogenic bacteria continues to present challenges for patients undergoing surgical procedures, and for the physicians that treat them. Even as molecular medicine produces ever faster and improved data sets for clinicians, it would benefit all medical personnel attempting to decolonize the nose to better understand the historical nasal decolonization data with specific reference to the ecological niche for these bacteria, as it has been recorded for more than a century. Much of the historical data points to the largest ecological niche for nasal Staphylococcus aureus as the vibrissae of the vestibulum nasi. A careful study shows that any topical antimicrobial preparation needs to successfully penetrate the deepest recesses of these specialized nasal hair follicles, if decolonization is to be adequately accomplished. This review highlights the most relevant data of the last 140 years concerning the staphylococcal ecological niche of the vibrissae. Also to be discussed will be a historical review of topical Mupirocin. Almost thirty years after its FDA approval, Mupirocin is still the most widely used topical antibiotic for decolonization therapy around the world. Correspondingly, new experimental in vitro data will be presented showing the differing efficacy of Mupirocin against multiple strains of HA-MRSA and CA- MRSA, based solely on the commercial topical formulation (non Mupirocin ingredients) that acts synergistically with the Mupirocin. Finally, the review will discuss why an understanding of these historical data is a vital component to integrate into any new or augmented nasal decolonization therapy.展开更多
Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean ...Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean are not well understood. This is a review of the limited studies in the Caribbean describing the prevalence, epidemiology, and molecular characteristics of MRSA in hospitalized and non-hospitalized patients. Relevant articles were searched and extracted from PubMed and Mendeley and a narrative review of the findings was constructed. An aggregate of 24 articles, from 1999 to 2020, was found from 10 of 27 countries. Majority of the studies were from Trinidad and Tobago (29%) and Jamaica (21%) while 50% were from Barbados, Dominican Republic, Martinique, Haiti, Cuba, St. Kits & Nevis, Guadeloupe, and Guyana. Approximately 75% of investigations were conducted on hospitalized patients versus 20% on outpatients. The data revealed geographical differences in the prevalence of MRSA within the Caribbean;20% - 100% of Staphylococcus aureus clinical isolates from hospitalized patients and outpatients were resistant to methicillin, macrolides, and fluoroquinolones, but susceptible to several non-beta lactam antibiotics, due to the widespread occurrence of CA-MRSA clone ST8 SCCmec IV, PVL positive. There was moderate prevalence of ST72 SCCmec V (14% - 25%) in both hospital and community settings in a few of the countries while ST30 SCCmec IV, PVL positive, was moderately prevalent (27%) only in Dominican Republic. Also, there was moderate prevalence of HA-MRSA ST5 SCCmec II (18%) in community settings in the Dominican Republic and Martinique, but high prevalence of HA-MRSA ST239 SCCmec III (60%) in hospitalized patients in Cuba and Trinidad & Tobago. The epidemiologic profile of MRSA in both hospital and community settings is changing in the Caribbean. Epidemiological studies on outpatient settings and the implementation of stringent hospital infection control measures are needed in the region.展开更多
Background: Colonization with methicillin-resistant Staphylococcus aureus(MRSA) poses a hygiene risk that does not spare field hospitals or military medical field camps during military deployments. Diagnostic options ...Background: Colonization with methicillin-resistant Staphylococcus aureus(MRSA) poses a hygiene risk that does not spare field hospitals or military medical field camps during military deployments. Diagnostic options for unambiguously identifying MRSA isolates are usually scarce in military environments. In this study, we assessed the stepwise application of two different selective agars for the specific identification of MRSA in screening analyses.Methods: Nasal swabs from 1,541 volunteers were subjected to thioglycollate broth enrichment and subsequently screened on CHROMagar MRSA selective agar for the identification of MRSA. The MRSA identity of suspiciouslooking colonies was confirmed afterwards or excluded by another selective agar, chrom ID MRSA. All isolates from the selective agars with MRSA-specific colony morphology were identified by biochemical methods and mass spectrometry.Results: The initial CHROMagar MRSA screening identified suspicious colonies in 36 out of 1541 samples. A total of 25 of these 36 isolates showed MRSA-like growth on chrom ID agar. Out of these 25 isolates, 24 were confirmed as MRSA, while one isolate was identified as Staphylococcus kloosii. From the 11 strains that did not show suspicious growth on chrom ID agar, 3 were methicillin-sensitive Staphylococcus aureus(MSSA, with one instance of cocolonization with Corynebacterium spp.), 2 were confirmed as MRSA(with 1 instance of co-colonization with MSSA), 2 were lost during passaging and could not be re-cultured, one could not be identified by the applied approaches, and the remaining 3 strains were identified as Staphylococcus saprophyticus, Staphylococcus hominis(co-colonized with Macrococcus caseolyticus) and Staphylococcus cohnii, respectively.Conclusion: The application of the selective agar CHROMagar MRSA alone proved to be too non-specific to allow for a reliable diagnosis of the presence of MRSA. The combined use of two selective agars in a stepwise approach reduced this non-specificity with an acceptably low loss of sensitivity. Accordingly, such a stepwise screening approach might be an option for resource-restricted military medical field camps.展开更多
基金Funding for this project was provided by Fundamental Research Grant Scheme(FRGS)of the Ministry of Higher Education,Malaysia(zuhainis@upm.edu.my)(Grant number:5524488)
文摘Objective: To investigate the antibacterial effect of selected lactic acid bacteria(LAB)biofilms on the planktonic and biofilm population of methicillin-resistant Staphylococcus aureus(MRSA)(S547).Methods: In this study, biofilm-forming LAB were isolated from tairu and kefir. Isolate Y1 and isolate KF were selected based on their prominent inhibition against test pathogens(using spot-on-agar method and agar-well-diffusion assay) and efficient biofilm production(using tissue culture plate method). They were then identified as Lactobacillus casei(L. casei) Y1 and Lactobacillus plantarum(L. plantarum) KF, respectively using16 S r DNA gene sequencing. The influence of incubation time, temperature and aeration on the biofilm production of L. casei Y1 and L. plantarum KF was also investigated using tissue culture plate method. The inhibitory activity of both the selected LAB biofilms was evaluated against MRSA(Institute for Medical Research code: S547) using L. plantarum ATCC 8014 as the reference strain.Results: L. casei Y1 showed the highest reduction of MRSA biofilms, by 3.53 log at48 h while L. plantarum KF records the highest reduction of 2.64 log at 36 h. In inhibiting planktonic population of MRSA(S547), both L. casei Y1 and L. plantarum KF biofilms recorded their maximum reduction of 4.13 log and 3.41 log at 24 h, respectively. Despite their inhibitory effects being time-dependent, both LAB biofilms exhibited good potential in controlling the biofilm and planktonic population of MRSA(S547).Conclusions: The results from this study could highlight the importance of analysing biofilms of LAB to enhance their antibacterial efficacy. Preferably, these protective biofilms of LAB could also be a better alternative to control the formation of biofilms by pathogens such as MRSA.
基金Universiti Kebangsaan Malaysia’s research university grant scheme (DCP-2017- 003/4)。
文摘This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to confirm the conjugation of the targeting ligand via the formation of amide bonds. Approximately 45% of VAN could be loaded into the aqueous cores, whereas 90% DAPT was detected using UV–vis spectrophotometry. In comparison to free drugs, the formulations controlled the release of drugs for > 72 h. Additionally, as demonstrated using CLSM and flow cytometry, the resulting formulation was capable of evading detection by macrophage cells. In comparison to free drugs, red blood cell membrane–DAPT–VAN liposomes, DAPT liposomes, and VAN liposomes reduced the MIC and significantly increased bacterial permeability, resulting in > 80% bacterial death within 4 h. Cytotoxicity tests were performed in vitro and in vivo on mammalian cells,in addition to hemolytic activity tests in human erythrocytes, wherein drugs loaded into the liposomes and RBCDVL exhibited low toxicity. Thus, the findings of this study provide insight about a dual antibiotic targeting strategy that utilizes liposomes and red blood cell membranes to deliver targeted drugs against MRSA.
文摘Objective:To synthesize zinc oxide nanoparticles(ZnONPs)and evaluate their antibacterial and wound healing effects against wounds infected with methicillin-resistant Staphylococcus aureus(MRSA).Methods:ZnONPs were prepared by sol-gel method and characterized by X-ray diffraction(XRD)analysis and scanning electron microscopy(SEM).A total of 18 rabbits were divided into three groups:the ZnONPs group,the gentamicin group and the control group.A wound of 3 cm^(2) was inflicted on each rabbit and contaminated with MRSA inoculum.Treatment was started from the fourth day post-surgery.Wound healing,microbiological analysis,and histopathological analysis were performed to assess the efficacy of ZnONPs ointment.Results:XRD analysis confirmed the hexagonal wurtzite structure of the ZnONPs with an average crystallite size of 29.23 nm.SEM revealed discoid-shaped ZnONPs with a rough surface and an average size of 48.36 nm.Energy-dispersive X-ray analysis confirmed the purity of ZnONPs.Moreover,the particle size ranged from 100-700 nm with a high agglomeration trend.Treatment with ZnONPs promoted MRSA-infected wound healing.In addition,ZnONPs showed a good antibacterial effect as evidenced by a dose-dependent increase in the zone of inhibition.Conclusions:ZnONPs accelerate the healing of MRSA-infected wounds.Therefore,it can be explored for the treatment of MRSA infection.
文摘Nasal colonization with pathogenic bacteria continues to present challenges for patients undergoing surgical procedures, and for the physicians that treat them. Even as molecular medicine produces ever faster and improved data sets for clinicians, it would benefit all medical personnel attempting to decolonize the nose to better understand the historical nasal decolonization data with specific reference to the ecological niche for these bacteria, as it has been recorded for more than a century. Much of the historical data points to the largest ecological niche for nasal Staphylococcus aureus as the vibrissae of the vestibulum nasi. A careful study shows that any topical antimicrobial preparation needs to successfully penetrate the deepest recesses of these specialized nasal hair follicles, if decolonization is to be adequately accomplished. This review highlights the most relevant data of the last 140 years concerning the staphylococcal ecological niche of the vibrissae. Also to be discussed will be a historical review of topical Mupirocin. Almost thirty years after its FDA approval, Mupirocin is still the most widely used topical antibiotic for decolonization therapy around the world. Correspondingly, new experimental in vitro data will be presented showing the differing efficacy of Mupirocin against multiple strains of HA-MRSA and CA- MRSA, based solely on the commercial topical formulation (non Mupirocin ingredients) that acts synergistically with the Mupirocin. Finally, the review will discuss why an understanding of these historical data is a vital component to integrate into any new or augmented nasal decolonization therapy.
文摘Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean are not well understood. This is a review of the limited studies in the Caribbean describing the prevalence, epidemiology, and molecular characteristics of MRSA in hospitalized and non-hospitalized patients. Relevant articles were searched and extracted from PubMed and Mendeley and a narrative review of the findings was constructed. An aggregate of 24 articles, from 1999 to 2020, was found from 10 of 27 countries. Majority of the studies were from Trinidad and Tobago (29%) and Jamaica (21%) while 50% were from Barbados, Dominican Republic, Martinique, Haiti, Cuba, St. Kits & Nevis, Guadeloupe, and Guyana. Approximately 75% of investigations were conducted on hospitalized patients versus 20% on outpatients. The data revealed geographical differences in the prevalence of MRSA within the Caribbean;20% - 100% of Staphylococcus aureus clinical isolates from hospitalized patients and outpatients were resistant to methicillin, macrolides, and fluoroquinolones, but susceptible to several non-beta lactam antibiotics, due to the widespread occurrence of CA-MRSA clone ST8 SCCmec IV, PVL positive. There was moderate prevalence of ST72 SCCmec V (14% - 25%) in both hospital and community settings in a few of the countries while ST30 SCCmec IV, PVL positive, was moderately prevalent (27%) only in Dominican Republic. Also, there was moderate prevalence of HA-MRSA ST5 SCCmec II (18%) in community settings in the Dominican Republic and Martinique, but high prevalence of HA-MRSA ST239 SCCmec III (60%) in hospitalized patients in Cuba and Trinidad & Tobago. The epidemiologic profile of MRSA in both hospital and community settings is changing in the Caribbean. Epidemiological studies on outpatient settings and the implementation of stringent hospital infection control measures are needed in the region.
文摘Background: Colonization with methicillin-resistant Staphylococcus aureus(MRSA) poses a hygiene risk that does not spare field hospitals or military medical field camps during military deployments. Diagnostic options for unambiguously identifying MRSA isolates are usually scarce in military environments. In this study, we assessed the stepwise application of two different selective agars for the specific identification of MRSA in screening analyses.Methods: Nasal swabs from 1,541 volunteers were subjected to thioglycollate broth enrichment and subsequently screened on CHROMagar MRSA selective agar for the identification of MRSA. The MRSA identity of suspiciouslooking colonies was confirmed afterwards or excluded by another selective agar, chrom ID MRSA. All isolates from the selective agars with MRSA-specific colony morphology were identified by biochemical methods and mass spectrometry.Results: The initial CHROMagar MRSA screening identified suspicious colonies in 36 out of 1541 samples. A total of 25 of these 36 isolates showed MRSA-like growth on chrom ID agar. Out of these 25 isolates, 24 were confirmed as MRSA, while one isolate was identified as Staphylococcus kloosii. From the 11 strains that did not show suspicious growth on chrom ID agar, 3 were methicillin-sensitive Staphylococcus aureus(MSSA, with one instance of cocolonization with Corynebacterium spp.), 2 were confirmed as MRSA(with 1 instance of co-colonization with MSSA), 2 were lost during passaging and could not be re-cultured, one could not be identified by the applied approaches, and the remaining 3 strains were identified as Staphylococcus saprophyticus, Staphylococcus hominis(co-colonized with Macrococcus caseolyticus) and Staphylococcus cohnii, respectively.Conclusion: The application of the selective agar CHROMagar MRSA alone proved to be too non-specific to allow for a reliable diagnosis of the presence of MRSA. The combined use of two selective agars in a stepwise approach reduced this non-specificity with an acceptably low loss of sensitivity. Accordingly, such a stepwise screening approach might be an option for resource-restricted military medical field camps.
