Medical Microbiology: Discovery of New Antimicrobial Drugs to Treat Clinically Relevant Antibiotic Resistant Pathogenic Bacteria

Edited version embargoed until 09.09.2022 Full version: Access restricted permanently due to 3rd party copyright restrictions. Restriction set on 11.09.2019 by SE, Doctoral CollegeAntimicrobial resistance (AMR) is one of the greatest world-wide threats to human health and urgent action is needed to reduce the potentially devastating social and economic impacts that may result from continued spread of drug resistant infections. These actions include discovery of new antibiotics and community engagement in AMR. Natural product screening methods are arguably the most efficient way to identify novel antibiotics, but can be frustrated by the repeated discovery of known compounds, wasting valuable resources, effort and time. Thus, exploiting obscure, hard to reach environments and implementing combined bioinformatic and proteomic screening approaches may short-cut the process of discovery of unique agents. In addition, educating and engaging the public will raise their awareness about AMR, which could reduce misuse of antibiotics. In this project, a total of 633 bacterial isolates were obtained from various clinical and environmental samples, including those provided by members of the general public. These isolates were screened for antimicrobial production using various antagonism assays. Draft genomes of 26 selected antagonistic strains were determined and mined in-silico using BAGEL-3 and antiSMASH-4.0 tools. Based on the findings, six isolates were further analysed using various proteomic strategies. The spectrum of activity, physicochemical properties and/or toxicity of purified compounds were investigated. This has led to the discovery of multiple novel compounds, including nisin-P, EU4-B synthetic peptide and EU4-natural product, which displayed diverse activity spectra towards pathogenic microorganisms. Aside from these results, the engagement of the general public, many of whom had limited prior awareness of AMR, is another important outcome. The optimized proteogenomic analysis has provided a means to shortcut some of the more laborious dereplication methods and has facilitated rapid identification of novel antimicrobial agents. In addition, this work has provided further evidence indicating that bacteria from the deep sea could be a rich source of novel compounds. Further investigation of all of the compounds discovered here may provide evidence justifying pre-clinical progression for future use against clinically relevant, drug resistant bacteria.Taif University, Saudi Arabi

Effectiveness of Oil-based Nanoemulsions with Molecular Docking of its Antimicrobial Potential

The biological properties of plant oils are improved by their conversion to nanoemulsions (NEs). This study evaluated the antimicrobial, antioxidant, and anti-hemolytic efficacy of coconut and salad rocket oils and their NEs. The result of the gas chromatography-mass spectroscopy analysis of the oils showed varied constituents such as palmitic acid, trimethylsilyl ester; 2,3-bis(acetyloxy)propyl laurate in salad rocket oil, 2-lauro-1,3-didecoin, n-butyl laurate; laurin, tri-; laurin in coconut oil. NEs diameter of salad rocket and coconut oils was 24.6 and 29.2 nm, respectively. More inhibitory activity of NEs compared with non-NEs form against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus flavus was detected. Coconut oil and its NEs caused 14.3% (anti-hemolysis 85.7%) and 22% hemolysis (anti-hemolysis 78%), respectively. Salad rocket oil and its NEs caused hemolysis 3.4% and 20.9%, respectively at 1000 µg/mL. Antioxidant activity of salad rocket and coconut oil reflected more IC50 (39.3 and 109.4 µg/mL) than its NEs (35.8 and 80.5 µg/mL), respectively. Molecular docking of trimethylsilyl ester and 2-lauro-1,3-didecoin against S. aureus (PDB=7BGE) and C. albicans protein (PDB=3DRA) revealed optimal binding mode that had the most energy interaction with the binding sites

Antibiofilm, Antimicrobial, Anti-Quorum Sensing, and Antioxidant Activities of Saudi Sidr Honey: In Vitro and Molecular Docking Studies

Sidr honey is a valuable source of bioactive compounds with promising biological properties. In the present study, antimicrobial, antioxidant, and anti-quorum sensing properties of Saudi Sidr honey were assessed, along with phytochemical analysis, via gas chromatography–mass spectrometry (GC-MS). In silico study was also carried out to study the drug-likeness properties of the identified compounds and to study their affinity with known target proteins assessed using molecular docking approach. The results showed that Saudi Sidr honey exhibited promising antibacterial activity, with MIC values ranging from 50 to 400 mg/mL and MBC values from 50 to >450 mg/mL. Interestingly, the Saudi Sidr honey was active against Candida auris and Candida neoformans, with an MIC value of about 500 mg/mL. Moreover, the Sidr honey showed important antioxidant activities (ABTS assay: IC50 5.41 ± 0.045 mg/mL; DPPH assay: IC50 7.70 ± 0.065 mg/mL) and β-carotene bleaching test results (IC50 ≥ 20 mg/mL). In addition, the Saudi Sidr honey was able to inhibit biofilm formation on glass slides at 1/2 MIC by 77.11% for Bacillus subtilis, 70.88% for Staphylococcus aureus, 61.79% for Escherichia coli, and 56.64% for Pseudomonas aeruginosa. Similarly, violacein production by Chromobacterium violaceum was reduced by about 56.63%, while the production of pyocyanin by P. aeruginosa was decreased to 46.27% at a low concentration of Saudi Sidr honey. ADMET properties showed that five identified compounds, namely, 1-cyclohexylimidazolidin-2-one, 3-Butyl-3-methylcyclohexanone, 4-butyl-3-methoxy-2-cyclo penten-1-one, 2,2,3,3-Tetramethyl cyclopropane carboxylic acid, and 3,5-dihydroxy-2-(3-methylbut-2-en-1-yl showed promising drug-likeness properties. The compound 3,5-dihydroxy-2-(3-methylbut-2-en-1-yl exhibited the highest binding energy against antimicrobial and antioxidant target proteins (1JIJ, 2VAM, 6B8A, 6F86, 2CDU, and 1OG5). Overall, the obtained results highlighted the promising potential of Saudi Sidr honey as a rich source of bioactive compounds that can be used as food preservatives and antimicrobial, antioxidant, and anti-quorum sensing molecules

Effectiveness of Oil-based Nanoemulsions with Molecular Docking of its Antimicrobial Potential

The biological properties of plant oils are improved by their conversion to nanoemulsions (NEs). This study evaluated the antimicrobial, antioxidant, and anti-hemolytic efficacy of coconut and salad rocket oils and their NEs. The result of the gas chromatography-mass spectroscopy analysis of the oils showed varied constituents such as palmitic acid, trimethylsilyl ester; 2,3-bis(acetyloxy)propyl laurate in salad rocket oil, 2-lauro-1,3-didecoin, n-butyl laurate; laurin, tri-; laurin in coconut oil. NEs diameter of salad rocket and coconut oils was 24.6 and 29.2 nm, respectively. More inhibitory activity of NEs compared with non-NEs form against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus flavus was detected. Coconut oil and its NEs caused 14.3% (anti-hemolysis 85.7%) and 22% hemolysis (anti-hemolysis 78%), respectively. Salad rocket oil and its NEs caused hemolysis 3.4% and 20.9%, respectively at 1000 µg/mL. Antioxidant activity of salad rocket and coconut oil reflected more IC50 (39.3 and 109.4 µg/mL) than its NEs (35.8 and 80.5 µg/mL), respectively. Molecular docking of trimethylsilyl ester and 2-lauro-1,3-didecoin against S. aureus (PDB=7BGE) and C. albicans protein (PDB=3DRA) revealed optimal binding mode that had the most energy interaction with the binding sites

Phytochemical Characterization and Efficacy of <i>Artemisia judaica</i> Extract Loaded Chitosan Nanoparticles as Inhibitors of Cancer Proliferation and Microbial Growth

Despite the advanced development in the field of drug discovery and design, fighting infectious and non-infectious diseases remains a major worldwide heath challenge due to the limited activity of currently used drugs. Nevertheless, in recent years, the approach of designing nanoparticles for therapeutic applications has gained more interest and promise for future use. Thus, the current study is focused on the evaluation of A. judaica extract and chitosan nanoparticles loaded extract (CNPsLE) for potential antimicrobial and anticancer activities. The HPLC analysis of the extract has shown the presence of various phenolic and flavonoid compounds, including kaempferol (3916.34 µg/mL), apigenin (3794.32 µg/mL), chlorogenic acid (1089.58 µg/mL), quercetin (714.97 µg/mL), vanillin (691.55 µg/mL), naringenin (202.14 µg/mL), and rutin (55.64 µg/mL). The extract alone showed higher MIC values against B. subtilis, E. coli, S. aureus, K. pneumonia, and C. albicans (62.5, 15.65, 15.62, 31.25, and 31.25 µg/mL, respectively), whereas lower MIC values were observed when the extract was combined with CNPsLE (0.97, 1.95, 3.9, 4.1, and 15.62 µg/mL, respectively). The extract exhibited low cytotoxicity against normal Vero cells with IC50 173.74 µg/mL in comparison with the cytotoxicity of the CNPsLE (IC50, 73.89 µg/mL). However, CNPsLE showed more selective toxicity against the human prostate cancer cell line (PC3) with IC50 of 20.8 µg/mL than the extract alone with 76.09 µg/mL. In the docking experiments, kaempferol and apigenin were revealed to be suitable inhibitors for prostate cancer (2Q7L). Overall, the obtained data highlighted the promising potential therapeutic use of CNPsLE as an anticancer and antimicrobial agent

Antibiogram of Urinary Tract Infections and Sepsis among Infants in Neonatal Intensive Care Unit

Neonatal infections including sepsis and urinary tract infections are considered among the leading causes of mortality in neonatal intensive care units (NICU). Thus, use of empiric antibiotics is very important in infected neonates and the success of this practice is mainly reliant on the availability of an up-to-date antibiogram for currently used antibiotic drugs. In this study, we aim to determine the bacteriological profile and antibiotic susceptibility pattern of bacteria isolated from blood or/and urine cultures belonging to patients at the NICU. A total of 54 urine samples were collected in the period between January 2015 and December 2019. Data of infants with positive urine and blood bacterial isolates were gathered retrospectively. The most commonly isolated bacteria from urine observed were K. pneumoniae (44%) and E. coli (39%), while Acinetobacter baumannii (33%) and K. pneumoniae (22%) predominated in neonatal blood samples. The majority of uropathogens and blood isolates exhibited low resistance to imipenem and tigecycline, respectively. These antibiotics would be recommended for future use as empirical treatment in neonates with urinary tract infections and/or sepsis. This investigation highlights the importance of surveillance studies to manage and ensure the effectiveness of treatment plan for critically ill infants

Antioxidant, Anticancer, Antibacterial, Antibiofilm Properties and Gas Chromatography and Mass Spectrometry Analysis of Manuka Honey: A Nature’s Bioactive Honey

Honey has a history of medical use and is known as bio-alternative therapy. This research assessed the phytochemical and biological activity of the medical grade manuka honey (MH). Gas chromatography–mass spectrometry (GC–MS) was chosen to investigate bioactive compounds of the MH. The DPPH and ABTS free radical scavenging and beta-carotene antioxidant activities as well as the antibacterial and antibiofilm effects against S. aureus, B. subtilis, E. coli and P. aeruginosa were all determined. Furthermore, to gauge anticancer properties of MH, a MTT assay was opted towards three cell lines, including HCT-116 (colon), A549 (lung) and MCF-7 (breast) cancer cells. The GC–MS analysis of the tested MH revealed the identification of various chemical constituents belonging to the fatty acids, phenols, and esters. The MH was found to have higher reducing power activity (DPPH IC50: 7.36; ABTS IC50: 4.49 mg/mL) than the beta-carotene bleaching power (IC50: 37.51 mg/mL). Similarly, the MH was noted to be more active against the planktonic and biofilm of Gram-positive bacteria. Furthermore, a dose-dependent anticancer potential was observed, although a significant anticancer potential was pointed out against the MCF-7 and A549 cell conforming to the IC50 values of 9.05 and 9.37 mg/mL, respectively. This study’s results have highlighted the MH’s chemical composition with significant bioactivities

Nanoencapsulation of natural products and their role in the preservation and control of contaminations in the food industry

Microbial resistance is a problem of high notoriety and importance, being investigated in several scientific areas. Directly correlated to the abuse of macrolides in the pandemic context, the difficulty in eliminating resistant microorganisms and the control of bacterial contamination in an industrial food environment have been increasingly worrying nowadays. The present study demonstrates hypotheses of microbial control using the encapsulation of essential oils and products of natural origin through the technology used in nanocomposites. The aid in the prevention and control of microorganisms with high antimicrobial resistance factors in food industry environments can be seen. Furthermore, new approaches and themes applied in the denaturation of pathogenic biofilms and nanoencapsulation and the use of common metals and transition metals are highlighted.info:eu-repo/semantics/publishedVersio

Bacterial Infections among Patients with Chronic Diseases at a Tertiary Care Hospital in Saudi Arabia

Infections caused by multi-drug-resistant bacteria in patients with chronic diseases have been associated with high mortality and morbidity. While few reports have evaluated bacterial infections in multiple chronic disease patients, the focus of the current study was to investigate the prevalence of bacterial infections and the susceptibility profiles of causative strains among various groups of patients suffering from chronic diseases. Microbiological reports of patients suffering from cancer, diabetes mellitus, cardiovascular diseases, kidney diseases, and skin burns were retrospectively collected from a tertiary hospital in Saudi Arabia. Approximately 54.2% of recruited patients were males, and positive urine was the most prevalent specimen associated with kidney disease patients (25%). Escherichia coli isolates were predominant among cardiovascular, kidney, and cancer patients. Staphylococcus aureus was commonly detected in diabetics and those with burns. Although resistance patterns varied based on the type of specimens and underlying diseases, Escherichia coli showed limited resistance to colistin, carbapenems, and tigecycline, while S. aureus demonstrated susceptibility to ciprofloxacin, gentamicin, and rifampin. These observations are crucial for clinicians and policymakers to ensure effective treatment plans and improve outcomes in these patients with comorbidity

Bacterial Coinfection and Antibiotic Resistance Profiles among Hospitalised COVID-19 Patients

While it is reported that COVID-19 patients are more prone to secondary bacterial infections, which are strongly linked to the severity of complications of the disease, bacterial coinfections associated with COVID-19 are not widely studied. This work aimed to investigate the prevalence of bacterial coinfections and associated antibiotic resistance profiles among hospitalised COVID-19 patients. Age, gender, weight, bacterial identities, and antibiotic sensitivity profiles were collected retrospectively for 108 patients admitted to the intensive care unit (ICU) and non-ICU ward of a single center in Saudi Arabia. ICU patients (60%) showed a significantly higher percentage of bacterial coinfections in sputum (74%) and blood (38%) samples, compared to non-ICU. Acinetobacter baumannii (56%) and Klebsiella pneumoniae (56%) were the most prevalent bacterial species from ICU patients, presenting with full resistance to all tested antibiotics except colistin. By contrast, samples of non-ICU patients exhibited infections with Escherichia coli (31%) and Pseudomonas aeruginosa (15%) predominantly, with elevated resistance of E. coli to piperacillin/tazobactam and trimethoprim/sulfamethoxazole. This alarming correlation between multi-drug resistant bacterial coinfection and admission to the ICU requires more attention and precaution with prescribed antibiotics to limit the spread of resistant bacteria and improve therapeutic management