AIMS & OBJECTIVES: In this study, we synthesized thirteen derivatives of gallic acid and evaluated their antibacterial potential against seven multi-drug resistant bacteria, as well as cytotoxic effects against human embryonic kidney cell line in vitro. Methods: 13 compounds were successfully synthesized with moderate to good yield and evaluated. Synthesized derivatives were characterized by using nuclear magnetic resonance spectroscopy, mass spectrometry, and Fourier transformation infrared spectroscopy. Antibacterial activity was determined using microdilution while cytotoxicyt was assessed using MTT assay.
RESULTS: The results of antibacterial assay showed that seven out of thirteen compounds exhibited antibacterial effects with compound 6 and 13 being most potent against Staphylococcus aureus (MIC 56 μg/mL) and Salmonella enterica (MIC 475 μg/mL) respectively. On the other hand, most of these compounds showed lower cytotoxicity against human embryonic kidney cells (HEK 293), with IC50 values ranging from over 700 μg/mL.
CONCLUSION: Notably, compound 13 was found to be non-toxic at concentrations as high as 5000 μg/mL. These findings suggest that the present synthetic derivatives of gallic acid hold potential for further studies in the development of potent antibacterial agents.
METHODS: A search was conducted in PubMed, Science Direct, and Google Scholar databases to identify eligible studies. Studies that reported the impact of COVID-19 pandemic on carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum beta-lactamase inhibitor (ESBL)-producing Enterobacteriaceae, vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Pseudomonas aeruginosa (CPE) were selected. Studies published in English language from the start of COVID-19 pandemic to July 2022 were considered for inclusion.
RESULTS: Thirty eligible studies were selected and most of them were from Italy (n = 8), Turkey (n = 3) and Brazil (n = 3). The results indicated changes in the rate of multidrug resistant bacteria, and the changes varied between the studies. Most studies (54.5%) reported increase in MRSA infection/colonization during the pandemic, and the increase ranged from 4.6 to 170.6%. Five studies (55.6%) reported a 6.8-65.1% increase in VRE infection/colonization during the pandemic. A 2.4-58.2% decrease in ESBL E. coli and a 1.8-13.3% reduction in ESBL Klebsiella pneumoniae was observed during the pandemic. For CRAB, most studies (58.3%) reported 1.5-621.6% increase in infection/colonization during the pandemic. Overall, studies showed increase in the rate of CRE infection/colonization during the pandemic. There was a reduction in carbapenem-resistant E. coli during COVID-19 pandemic, and an increase in carbapenem-resistant K. pneumoniae. Most studies (55.6%) showed 10.4 - 40.9% reduction in the rate of CRPA infection during the pandemic.
CONCLUSION: There is an increase in the rate of multidrug resistant gram positive and gram negative bacteria during the COVID-19 pandemic. However, the rate of ESBL-producing Enterobacteriaceae and CRPA has decrease during the pandemic. Both infection prevention and control strategies and antimicrobial stewardship should be strengthen to address the increasing rate of multidrug resistant gram positive and gram negative bacteria.
METHOD: Electronic search (PubMed, Scopus and Google scholar) was conducted using the following search terms: "MRSA OR Methicillin Resistant Staphylococcus aureus AND Nigeria." Reference list of selected studies was scanned to identify more studies. Studies published between 2007 and 2017 that tested at least 30 non-duplicate S. aureus isolates were selected. An independent reviewer extracted data from the studies using a standardized form.
RESULTS: Twelve studies were included in this review. Overall, prevalence of MRSA infection increased from 18.3% (2009) to 42.3% (2013). The prevalence of MRSA infection was less than 50% in all the regions during the period under review. There was a decline in the prevalence of MRSA infection in the North-East (from 12.5% to 8.0%) between 2007 and 2012, and an increase in the South-West (from 20.2% to 47.4%) between 2006 and 2010. Wound, blood and urine specimens had the highest proportion of MRSA isolates. Non-susceptibility of MRSA strains to cotrimoxazole and tetracycline was greater than 85%.
CONCLUSION: Prevalence of MRSA infection in Nigeria is rising, albeit regional variations. Non-susceptibility to commonly prescribed, orally available and inexpensive antibiotics was high. Antimicrobial resistance surveillance system, infection control, and antimicrobial stewardship interventions are recommended.
Methods: The in vitro effect of tannins was studied against MRSA reference strain (ATCC 43300) and MRSA clinical strains utilizing antimicrobial assays in conjunction with both scanning and transmission electron microscopy. To reveal the influence of tannins in MRSA protein synthesis disruption, we utilized next-generation sequencing (NGS) to provide further insight into the novel protein synthesis transcriptional response of MRSA exposed to these compounds.
Results: Tannins possessed both bacteriostatic and bactericidal activity with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 0.78 and 1.56 mg/mL, respectively, against all tested MRSA. Scanning and transmission electron microscopy of MRSA treated with tannins showed decrease in cellular volume, indicating disruption of protein synthesis.
Conclusion: Analysis of a genome-wide transcriptional profile of the reference strain ATCC 43300 MRSA in response to tannins has led to the finding that tannins induced significant modulation in essential ribosome pathways, which caused a reduction in the translation processes that lead to inhibition of protein synthesis and obviation of bacterial growth. These findings highlight the potential of tannins as new promising anti-MRSA agents in clinical application such as body wash and topical cream or ointments.
METHODS: Time-kill analysis of one MRSA reference strain (ATCC 43300) and three clinical isolates (WM3, BM1 and KJ7) for both compounds was first performed to provide the bacteriostatic/bactericidal profile. Then, MRSA ATCC 43300 strain treated with both compounds was interrogated by NGS.
RESULTS: Both stigmasterol and lupeol possessed bacteriostatic properties against all MRSA tested; however, lupeol exhibited both bacteriostatic and bactericidal properties within the same minimum inhibitory concentration and minimum bactericidal concentration values against BM1 (12.5mg/mL). Transcriptome profiling of MRSA ATCC 43300 revealed significant modulation of gene expression with multiple desirable targets by both compounds, which caused a reduction in the translation processes leading to inhibition of protein synthesis and prevention of bacterial growth.
CONCLUSIONS: This study highlights the potential of both stigmasterol and lupeol as new promising anti-MRSA agents.