Integrating MALDI-TOF Mass Spectrometry with Machine Learning Techniques for Rapid Antimicrobial Resistance Screening of Foodborne Bacterial Pathogens.

Although MALDI-TOF mass spectrometry (MS) is considered as the gold standard for rapid and cost-effective identification of microorganisms in routine laboratory practices, its capability for antimicrobial resistance (AMR) detection has received limited focus. Nevertheless, recent studies explored the predictive performance of MALDI-TOF MS for detecting AMR in clinical pathogens when machine learning techniques are applied. This chapter describes a routine MALDI-TOF MS workflow for the rapid screening of AMR in foodborne pathogens, with Campylobacter spp. as a study model.

Genomic Pipeline for Analysis of Mutational Events in Bacteria.

Unveiling the strategies of bacterial adaptation to stress constitute a challenging area of research. The understanding of mechanisms governing emergence of resistance to antimicrobials is of particular importance regarding the increasing threat of antibiotic resistance on public health worldwide. In the last decades, the fast democratization of sequencing technologies along with the development of dedicated bioinformatical tools to process data offered new opportunities to characterize genomic variations underlying bacterial adaptation. Thereby, research teams have now the possibility to dive deeper in the deciphering of bacterial adaptive mechanisms through the identification of specific genetic targets mediating survival to stress. In this chapter, we proposed a step-by-step bioinformatical pipeline enabling the identification of mutational events underlying biocidal stress adaptation associated with antimicrobial resistance development using Escherichia marmotae as an illustrative model.

Bioinformatic Pipeline for Profiling Foodborne Bacterial Ecology and Resistome from Short-Read Metagenomics.

Next-generation sequencing revolutionized food safety management these last years providing access to a huge quantity of valuable data to identify, characterize, and monitor bacterial pathogens on the food chain. Shotgun metagenomics emerged as a particularly promising approach as it enables in-depth taxonomic profiling and functional investigation of food microbial communities. In this chapter, we provide a comprehensive step-by-step bioinformatical workflow to characterize bacterial ecology and resistome composition from metagenomic short-reads obtained by shotgun sequencing.

Development and antimicrobial activity of composite edible films of chitosan and nisin incorporated with perilla essential oil-glycerol monolaurate emulsions.

Aquatic products are highly susceptible to spoilage, and preparing composite edible film with essential oil is an effective solution. In this study, composite edible films were prepared using perilla essential oil (PEO)-glycerol monolaurate emulsions incorporated with chitosan and nisin, and the film formulation was optimized by response surface methodology. These films were applied to ready-to-eat fish balls and evaluated over a period of 12 days. The films with the highest inhibition rate against Staphylococcus aureus were acquired using a polymer composition of 6 µL/mL PEO, 18.4 µg/mL glycerol monolaurate, 14.2 mg/mL chitosan, and 11.0 µg/mL nisin. The fish balls coated with the optimal edible film showed minimal changes in appearance during storage and significantly reduced total bacterial counts and total volatile basic nitrogen compared to the control groups. This work indicated that the composite edible films containing essential oils possess ideal properties as antimicrobial packaging materials for aquatic foods.

Antimicrobial adhesive self-healing hydrogels for efficient dental biofilm removal from periodontal tissue.

OBJECTIVES: Oral biofilms, including pathogens such as Porphyromonas gingivalis, are involved in the initiation and progression of various periodontal diseases. However, the treatment of these diseases is hindered by the limited efficacy of many antimicrobial materials in removing biofilms under the harsh conditions of the oral cavity. Our objective is to develop a gel-type antimicrobial agent with optimal physicochemical properties, strong tissue adhesion, prolonged antimicrobial activity, and biocompatibility to serve as an adjunctive treatment for periodontal diseases. METHODS: Phenylboronic acid-conjugated alginate (Alg-PBA) was synthesized using a carbodiimide coupling agent. Alg-PBA was then combined with tannic acid (TA) to create an Alg-PBA/TA hydrogel. The composition of the hydrogel was optimized to enhance its mechanical strength and tissue adhesiveness. Additionally, the hydrogel's self-healing ability, erosion and release profile, biocompatibility, and antimicrobial activity against P. gingivalis were thoroughly characterized. RESULTS: The Alg-PBA/TA hydrogels, with a final concentration of 5 wt% TA, exhibited both mechanical properties comparable to conventional Minocycline gel and strong tissue adhesiveness. In contrast, the Minocycline gel demonstrated negligible tissue adhesion. The Alg-PBA/TA hydrogel also retained its rheological properties under repeated 5 kPa stress owing to its self-healing capability, whereas the Minocycline gel showed irreversible changes in rheology after just one stress cycle. Additionally, Alg-PBA/TA hydrogels displayed a sustained erosion and TA release profile with minimal impact on the surrounding pH. Additionally, the hydrogels exhibited potent antimicrobial activity against P. gingivalis, effectively eliminating its biofilm without compromising the viability of MG-63 cells. SIGNIFICANCE: The Alg-PBA/TA hydrogel demonstrates an optimal combination of mechanical strength, self-healing ability, tissue adhesiveness, excellent biocompatibility, and sustained antimicrobial activity against P. gingivalis. These attributes make it superior to conventional Minocycline gel. Thus, the Alg-PBA/TA hydrogel is a promising antiseptic candidate for adjunctive treatment of various periodontal diseases.

Application progress of rosin in food packaging: A review.

Foodborne illness caused by Gram bacteria is the most important food safety issue worldwide. Food packaging film is a very important means to extend the shelf life of food. It reduces microbial contamination and provides food safety assurance during the sales process. However, the food packaging material is derived from plastic. Most plastics are not only non-degradable but also harmful to human health. Biodegradable natural polymers are an ideal substitute, but their poor mechanical properties, hydrophilicity and weak antibacterial properties limit their applications. Rosin is an oily pine ester in the pine family, which is a natural renewable resource with a wide range of sources. It is widely used in various fields, such as surfactants, adhesives, drug loading, antibacterial, etc. However, there are only a few reports on the application of rosin in food packaging. It is worth noting that the unique hydrogenated phenanthrene ring structure of rosin can enhance the thermal stability, hydrophobicity and antibacterial properties of food packaging. More importantly, rosin has a wide range of sources, good biocompatibility, and can be degraded in nature. These advantages are conducive to the application of rosin in food packaging. However, previous reviews focused on resins, silicone rubbers and surfactants. In this review we will focus on the application of rosin in food packaging.

Population Structure and Antimicrobial Resistance in Campylobacter jejuni and C. coli Isolated from Humans with Diarrhea and from Poultry, East Africa.

Campylobacteriosis and antimicrobial resistance (AMR) are global public health concerns. Africa is estimated to have the world's highest incidence of campylobacteriosis and a relatively high prevalence of AMR in Campylobacter spp. from humans and animals. Few studies have compared Campylobacter spp. isolated from humans and poultry in Africa using whole-genome sequencing and antimicrobial susceptibility testing. We explored the population structure and AMR of 178 Campylobacter isolates from East Africa, 81 from patients with diarrhea in Kenya and 97 from 56 poultry samples in Tanzania, collected during 2006-2017. Sequence type diversity was high in both poultry and human isolates, with some sequence types in common. The estimated prevalence of multidrug resistance, defined as resistance to >3 antimicrobial classes, was higher in poultry isolates (40.9%, 95% credible interval 23.6%-59.4%) than in human isolates (2.5%, 95% credible interval 0.3%-6.8%), underlining the importance of antimicrobial stewardship in livestock systems.

Infectious Disease Physicians' Knowledge and Practices Regarding Wastewater Surveillance, United States, 2024.

A survey of US infectious disease physicians indicated that few regularly reviewed wastewater surveillance (WWS) data but many reported examples of how WWS has affected or could affect their clinical practice. WWS data can be useful for physicians, but increased communication between public health professionals and physicians regarding WWS could improve its utility.

Chlorine Inactivation of Elizabethkingia spp. in Water.

We performed chlorine inactivation experiments for Elizabethkingia anophelis and E. meningoseptica bacterial strains from clinical and environmental sources. Free chlorine concentration × contact time values <0.04 mg·min/L achieved 99.9% inactivation of Elizabethkingia species, indicating chlorine susceptibility. Measures to control biofilm producing pathogens in plumbing are needed to prevent Elizabethkingia bacterial infections.

Oxacillinase-484-Producing Enterobacterales, France, 2018-2023.

We examined the emergence and characteristics of oxacillinase-484-producing Enterobacterales in France during 2012-2023. Genomic analysis identified 2 predominant sequence types in Escherichia coli: ST410 and ST1722. Plasmid analysis revealed that blaOXA-484 genes were carried mostly on an IncX3-type plasmid associated with genetic elements including insertion sequences IS3000 and ISKpn19.

Chromosomally located blaCMH in Enterobacter cloacae complex across human-bird-environment interfaces: A one-health perspective.

To improve the understanding of antimicrobial resistance (AMR) in migratory birds derived-Enterobacter cloacae (E. cloacae) complex and its spread at the human-bird-environment interface, we isolated 11 strains of third-generation cephalosporin-resistant E. cloacae from 1003 specimens from 29 migratory bird species over two years in Chongming, Shanghai, China. The comprehensive analysis incorporated second- and third-generation sequencing techniques and extensive bioinformatic analysis. Four human-associated E. cloacae sequence types (STs), including ST432, ST412, ST1, and ST639, were found in migratory birds. We confirmed that the blaCMH-4 and blaCMH-6 genes were the major genotypes of the ß-lactamase resistance genes in E. cloacae found in migratory birds. In addition, a thorough genomic analysis was performed on a global collection of 398 E. cloacae isolates carrying the blaCMH gene from 46 different countries. China had the highest proportion with 19.10 % (76/398), followed by Singapore with 18.34 % (73/398), Nigeria with 15.83 % (63/398), and the USA with 14.07 % (56/398). The first transmission of E. cloacae carrying blaCMH-4 and blaCMH-6 was defined around 1894 and 1549, respectively. Time-based phylogenetic analysis revealed that host jumps among humans, birds, and the environment led to the emergence of modern strains with ESBL- and carbapenem-resistant genes from about 2004 to 2016. The detection rate of insertion sequences (IS) of E. cloacae carrying blaCMH from human sources is higher than that from migratory bird sources, which is related to the different genetic environments caused by antibiotic selective pressure. It is crucial to have a comprehensive understanding of the characteristics exhibited by blaCMH producing E. cloacae in different ecological environments. Our results contribute to the effective monitoring and implementation of proactive strategies to reduce the spread of multidrug-resistant E. cloacae.

Antibiotic-Polyphosphate Nanocomplexes: A Promising System for Effective Biofilm Eradication.

Purpose: The eradication of bacterial biofilms poses an enormous challenge owing to the inherently low antibiotic susceptibility of the resident microbiota. The complexation of antibiotics with polyphosphate can substantially improve antimicrobial performance. Methods: Nanoparticular complexes of the model drug colistin and polyphosphate (CP-NPs) were developed and characterized in terms of their particle size and morphology, polydispersity index (PDI), zeta potential, and cytotoxicity. Enzyme-triggered monophosphate and colistin release from the CP-NPs was evaluated in the presence of alkaline phosphatase (AP). Subsequently, antimicrobial efficacy was assessed by inhibition experiments on planktonic cultures, as well as time-kill assays on biofilms formed by the model organism Micrococcus luteus. Results: The CP-NPs exhibited a spherical morphology with particle sizes <200 nm, PDI <0.25, and negative zeta potential. They showed reduced cytotoxicity toward two human cell lines and significantly decreased hemotoxicity compared with native colistin. Release experiments with AP verified the enzymatic cleavage of polyphosphate and subsequent release of monophosphate and colistin from CP-NPs. Although CP-NPs were ineffective against planktonic M. luteus cultures, they showed major activity against bacterial biofilms, outperforming native colistin treatment. Strongly elevated AP levels in the biofilm state were identified as a potential key factor for the observed findings. Conclusion: Accordingly, polyphosphate-based nanocomplexes represent a promising tool to tackle bacterial biofilm.

Trends and geographical variations in outpatient antimicrobial consumption in Ireland in relation to socio-economic deprivation.

Background: Different factors have been associated with changes in antimicrobial consumption rates in Ireland, however the relationship between socio-economic deprivation and antimicrobial consumption has not been explored. The presented ecological analysis explores the temporal and geographical variation in outpatient antimicrobial consumption and socio-economic deprivation in Ireland from January 2015 to March 2022. Method: Deprivation index (DI) was used as a socio-economic proxy. A multilevel mixed model was applied to explore temporal variation and analyse the longitudinal antimicrobial consumption (DID) in relation to DI. Furthermore, maps were generated based on antimicrobial consumption rates, and spatial autocorrelation analyses were carried out to study geographical variation in antimicrobial consumption rates. Results: The antimicrobial consumption rates per month varied from 26.2 DID (January 2015) to 22.1 DID (March 2022) showing an overall reduction of 16 %. Overall, total antimicrobial consumption in the multilevel model showed a consistent correlation with higher DI score (6.6 (95%CI 3.9 to 9.3)), and winter season (3.6 (95%CI 3.2 to 3.9)). In contrast, before COVID-19 showed significant lower antimicrobial consumption rates compared to during COVID-19 (-4.0 (95%CI -4.7 to -3.23)). No consistent trends were observed for geographical variation between areas. Conclusion: Antimicrobial consumption rates decreased from 2015 to 2021 in Ireland. No geographical patterns were observed in antimicrobial consumption rates but associations between deprivation and antimicrobial consumption rates were observed.

Evaluation of a Ureteral Stent Removal Protocol in Adult Kidney Transplant Recipients.

Existing literature on best practices to reduce the risk of infectious complications associated with ureteral stent removal in kidney transplant recipients is limited. Prior to 2021, a formal process surrounding stent removal was not in place at our institution. In June 2021, a stent removal protocol was established. This protocol included the following: obtaining a preprocedure urine culture, prescribing universal culture-directed antimicrobial prophylaxis, earlier stent removal posttransplant, and patient education. We performed a retrospective quasi-experimental study of kidney transplant recipients who had their stents removed between July 2020 and June 2022. The primary outcome was the incidence of infectious complications within 30 days. Infectious complications were defined as urinary tract infection and bacteremia due to urinary source, as well as hospitalization, emergency department visit, or outpatient encounter for possible urinary tract infection. Secondary objectives included infectious and immunologic complications within 30 days to 1 year from transplant. During this study period, 239 adult kidney transplant recipients were included: 88 in the preprotocol group and 151 in the protocol group. The median time to stent removal was shorter in the protocol group (25 vs 36 days, P < .001). More patients in the protocol group received preprocedure antibiotics (99% vs 36%, P < .001). Infectious complications were higher in the preprotocol group (9% vs 3%, P = .035). Overall, the stent removal protocol was associated with fewer infectious complications (odds ratio, 0.18; 95% CI, 0.05-0.73). Further investigation is necessary to determine which individual interventions, if any, drive this benefit.

Comparative Analysis of Antimicrobial Properties and Physical Properties of Mineral Trioxide Aggregate Mixed With Distilled Water, Chlorhexidine, and Sodium Hypochlorite Solutions: An In Vitro Study.

BACKGROUND:  Endodontics widely uses mineral trioxide aggregate (MTA) because of its excellent sealing ability, biocompatibility, and capacity to promote healing. However, the effectiveness of MTA can vary depending on the blending solution used. Endodontics commonly employ chlorhexidine (CHX) and sodium hypochlorite (NaOCl), but their impact on MTA's properties necessitates further investigation. MATERIALS AND METHODS: We blended MTA with the specified solutions and prepared it for testing according to the manufacturer's instructions. The study was divided into four groups: group 1 involved MTA blended with distilled water, group 2 consisted of MTA blended with 0.12% CHX solution (PerioGard, Colgate-Palmolive, Osasco, Brazil), group 3 included MTA blended with 0.2% CHX solution (Corsodyl, GlaxoSmithKline Consumer Healthcare, England, UK), and group 4 comprised MTA blended with 5% NaOCl (Azure Research Lab Pvt. Ltd., New Delhi, India). The antimicrobial activity of each group was assessed using the agar diffusion method against Enterococcus faecalis, Candida albicans, and Streptococcus mutans. We measured the compressive strength at 1, 3, 7, and 21 days using an Instron universal testing machine (Hounsfield Test Equipment, Redhill, UK). Statistical significance was evaluated through one-way ANOVA and Kruskal-Wallis tests, with p values <0.05 considered significant. RESULTS:  Group 3 (MTA blended with 0.2% CHX) exhibited the highest antimicrobial efficacy, with significantly larger inhibition zones against Enterococcus faecalis (25.25 ± 0.21 mm vs. 13.33 ± 0.12 mm, p = 0.011), Candida albicans (29.58 ± 0.24 mm vs. 16.97 ± 0.16 mm, p = 0.004), and S. mutans (26.37 ± 0.15 mm vs. 14.55 ± 0.25 mm, p = 0.027). Group 4 (MTA blended with 5% NaOCl) showed the highest compressive strength at one and three days (p = 0.032 and p = 0.021, respectively), but by 21 days, group 2 demonstrated the greatest compressive strength (p = 0.044). CONCLUSION:  MTA mixed with 0.2% CHX provides superior antimicrobial properties, making it suitable for enhanced microbial control in endodontic treatments. Conversely, MTA mixed with 0.12% CHX offers optimal long-term compressive strength. These findings guide selecting MTA formulations to maximize performance based on clinical needs.

Demographic and Microbiological Profile of Corneal Ulcers in Eastern India.

PURPOSE: To evaluate the microbiological profile of corneal ulcers presenting at a tertiary care eye hospital in eastern Uttar Pradesh (UP), India. METHODS: This retrospective, observational study included patients with corneal ulcers who underwent corneal scraping and microbiological examination of the sample from May 2014 to October 2023. The demographic details, predisposing factors, and clinical examination data of the patients were noted. Microbiology report of staining and culture (blood agar and Sabaraud's dextrose agar) of corneal scraping sample was analyzed in percentage. Reports of antimicrobial susceptibility testing were also noted and analyzed. RESULTS: A total of 695 corneal scraping samples were examined during the study period. The mean age of the patients was 45.95 years. Among the patients, 412 (59.28%) were males and 283 (40.72%) were females. Among the patients, 402 (57.84%) belonged to an agricultural background. Trauma was the most common predisposing factor associated with 350 (50.36%) cases. The corneal scraping samples were stain-positive in 455 (65.47%) cases, of which, 130 (28.57%) were gram-positive and 325 (71.43%) were positive on potassium hydroxide (KOH) mount. Culture was positive in 306 (44.03%) cases, of which, bacterial isolates were found in 78 (25.49%), and fungal isolates were found in 228 (74.51%). Fusarium was the most common fungal isolate in 72 (31.58%) cases followed by Aspergillus in 60 (26.32%) cases. Among the bacterial isolates, Staphylococcus aureus was the most common in 20 (25.64%) cases followed by Pseudomonas and Streptococcus. The antimicrobial susceptibility testing showed that 47 (60.26%) of the bacterial isolates were sensitive to fluoroquinolones while the rest 31 (39.74%) were resistant. All the Staphylococcus aureus strains (including four cases of methicillin-resistant Staphylococcus aureus) were susceptible to vancomycin and linezolid, while 7 (35%) were resistant to moxifloxacin. None of the Pseudomonas strains were multidrug resistant. Among the fungal isolates, 220 (96.49%) were susceptible to voriconazole and 189 (82.89%) were sensitive to amphotericin B. CONCLUSION: Fungal corneal ulcers are more common compared to bacterial ulcers in eastern India, particularly eastern UP and Bihar. This article highlights the importance of microbial testing and provides insight into the prevalent organisms and their antimicrobial susceptibility pattern in this geographic location, the knowledge of which will help clinicians in the appropriate management of these cases.

Secondary Metabolites of Halobacillus sp.: Antimicrobial and Antioxidant Activity, Biological Compatibility, and Gas Chromatography-Mass Spectrometry (GC-MS) Analysis.

Background The rise of infectious diseases and the emergence of resistant pathogens pose significant challenges to human health. In response to this global threat, researchers are exploring novel sources of bioactive compounds for effective antimicrobial therapies. One avenue of investigation is the study of halophilic bacteria and their secondary metabolites. These bacteria thrive under extreme conditions and produce valuable bioactive metabolites, which have the potential for therapeutic applications. Methods In this study, the potent bacterial cultures obtained from the Payanur salt pan, Tamil Nadu, were analyzed for the antimicrobial activity of their metabolites. The secondary metabolites were obtained from the halophilic bacteria by culturing the bacteria in 8% NaCl. The resultant secondary metabolites produced were extracted using ethyl acetate and their antimicrobial property was studied using the well diffusion method. The minimum inhibitory concentration (MIC) of these metabolites against five clinical pathogens, namely, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans was determined. Their antioxidant property was studied using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method and biological compatibility was determined by hemolytic assay of the secondary metabolites. Results The potent halophilic bacteria isolated from salt pan bacteria were phenotypically and genotypically identified as Halobacillus sp. The secondary metabolites extracted from these bacteria yielded 110 mg of crude metabolites. The antimicrobial activity of crude metabolites shows a moderate zone of inhibition of 14 mm for P. aeruginosa, 13 mm for E. coli and C. albicans, and 11 mm for S. aureus. The minimum inhibitory concentration was 128 µg/mL for E. coli, P. aeruginosa, and C. albicans, which was found to be the best growth inhibition concentration. The DPPH scavenging activity shows a higher activity till the concentration of 64 µg/mL. The hemolytic activity of 25% is obtained at 128 µg/mL and below 64 µg/mL, there is no hemolytic activity. The gas chromatography-mass spectrometry (GC-MS) analysis of the secondary metabolites shows the presence of 17 compounds. Among them, there were four major compounds: (i) cyclo(L-prolyl-L-valine) (probability of 95.63%), (ii) pyrrolo[1,2-a]pyrazine- 1,4-dione,hexahydro-3-(2-methylpropl) (probability of 94.45%), (iii) 2,5-piperazinedione,3,6-bis(2-methylpropyl) (probability of 71.94%) and (iv) pyrrolo[1,2-a]pyrazine-1,4-dione,hexahydro-3-(phenylmethyl) (probability of 88.01%). Conclusion In conclusion, the isolated bacterium is confirmed to be Halobacillus sp. and the secondary metabolites produced by this bacterium could be the potential source for the development of novel antimicrobial and antioxidant compounds that are highly biologically compatible. Further research may help to develop novel compounds in the pharmaceutical industry.

Human breast milk isolated lactic acid bacteria: antimicrobial and immunomodulatory activity on the Galleria mellonella burn wound model.

Introduction: Managing burn injuries is a challenge in healthcare. Due to the alarming increase in antibiotic resistance, new prophylactic and therapeutic strategies are being sought. This study aimed to evaluate the potential of live Lactic Acid Bacteria for managing burn infections, using Galleria mellonella larvae as an alternative preclinical animal model and comparing the outcomes with a common antibiotic. Methods: The antimicrobial activity of LAB isolated from human breast milk was assessed in vitro against Pseudomonas aeruginosa ATCC 27853. Additionally, the immunomodulatory effects of LAB were evaluated in vivo using the G. mellonella burn wound infection model. Results and discussion: In vitro results demonstrated the antimicrobial activity of Lactic Acid Bacteria against P. aeruginosa. In vivo results show that their prophylactic treatment improves, statistically significant, larval survival and modulates the expression of immunity-related genes, Gallerimycin and Relish/NF-κB, strain-dependently. These findings lay the foundation and suggest a promising alternative for burn wound prevention and management, reducing the risk of antibiotic resistance, enhancing immune modulation, and validating the potential G. mellonella as a skin burn wound model.

High-resolution 2D solid-state NMR provides insights into nontuberculous mycobacteria.

We present a high-resolution magic-angle spinning (MAS) solid-state NMR (ssNMR) study to characterize nontuberculous mycobacteria (NTM). We studied two different NTM strains, Mycobacterium smegmatis, a model, non-pathogenic strain, and Mycobacterium abscessus, an emerging and important human pathogen. Hydrated NTM samples were studied at natural abundance without isotope-labelling, as whole-cells versus cell envelope isolates, and native versus fixed sample preparations. We utilized 1D13C and 2D 1H-13C ssNMR spectra and peak deconvolution to identify NTM cell-wall chemical sites. More than ∼100 distinct 13C signals were identified in the ssNMR spectra. We provide tentative assignments for ∼30 polysaccharides by using well resolved 1H/13C chemical shifts from the 2D INEPT-based 1H-13C ssNMR spectrum. The signals originating from both the flexible and rigid fractions of the whole-cell bacteria samples were selectively analyzed by utilizing either CP or INEPT based 13C ssNMR spectra. CP buildup curves provide insights into the dynamical similarity of the cell-wall components for NTM strains. Signals from peptidoglycan, arabinogalactan and mycolic acid were identified. The majority of the 13C signals were not affected by fixation of the whole cell samples. The isolated cell envelope NMR spectrum overlap with the whole-cell spectrum to a large extent, where the latter has more signals. As an orthogonal way of characterizing these bacteria, electron microscopy (EM) was used to provide spatial information. ssNMR and EM data suggest that the M. abscessus cell-wall is composed of a smaller peptidoglycan layer which is more flexible compared to M. smegmatis, which may be related to its higher pathogenicity. Here in this work, we used high-resolution 2D ssNMR first time to characterize NTM strains and identify chemical sites. These results will aid the development of structure-based approaches to combat NTM infections.

Investigating the Efficacy of Various Natural Products in Raw Form against Multidrug-Resistant Bacteria.

BACKGROUND: The alarming increase in antibiotic resistance urges alternative and efficacious antimicrobial solutions. Historically, medicinal plants have been used for therapeutic purposes, such as relieving pain and healing wounds. However, the evaluation of the natural therapeutic effects of medicinal plants in a manner that resembles how humans typically consume them is lacking. Therefore, in this study, many medicinal plants known to have some antimicrobial effects, including Frankincense, Garlic, Myrrh, and Ginger, were evaluated for their direct antibacterial activity in raw form. MATERIALS AND METHODS: The direct antimicrobial activity of medicinal plants was evaluated against a variety of Gram-positive and Gram-negative bacterial strains, such as Staphylococcus aureus (S. Aureus), Acinetobacter baumannii and Klebsiella pneumoniae using agar well diffusion method and turbidity measurements in suspension culture. RESULTS: Out of all the tested medicinal plants, only raw garlic (Allium sativum) powder, when dissolved in water or vinegar, offered a straightforward antibacterial activity. A combination of garlic extract and vinegar increased antibacterial activity. Aqueous garlic extracts displayed robust antimicrobial activity against many resistant bacteria. Other medicinal plants used in this study had absent or minimal antibacterial effects. CONCLUSION: Only garlic in its raw form was effective against antibiotic-resistant bacteria. The increase in the antibacterial activity of garlic when combined with vinegar suggests the synergistic activity of garlic. The straightforward antibacterial action of raw garlic may be strategically harnessed to combat the continuous challenge of increasing antibiotic resistance. This work promotes additional testing of more natural products (in raw form) and assesses their therapeutic effects clinically.