The Untargeted Phytochemical Profile of Three Meliaceae Species Related to In Vitro Cytotoxicity and Anti-Virulence Activity against MRSA Isolates

Background: A high mortality rate is associated with about 80% of all infections worldwide, mainly due to antimicrobial resistance. Various antimicrobial and cytotoxic activities have been proposed for Meliaceae species. This study aimed to evaluate the in vitro anti-virulence and cytotoxic effect of the leaf extracts of Aphanamixis polystachya, Toona ciliata and Melia azedarach against five MRSA strains and on three cancer cell lines, followed by biological correlation to their encompassed phytoconstituents. Material and Methods: We explored three plants of this family against a panel of Methicillin-resistant Staphylococcus aureus (MRSA) strains and several cancer cell lines to select the most promising candidates for further in vivo and preclinical studies. The phytochemical composition was evaluated by UHPLC–QTOF–MS untargeted profiling. Cell viability was assessed by SRB assay. Minimum Inhibitory Concentration was carried out by using the agar micro-dilution technique. Inhibition of biofilm formation and preformed biofilm disruption were assessed spectrophotomertically, according to the Sultan and Nabil method (2019). Results: A total of 279 compounds were putatively annotated to include different phytochemical classes, such as flavonoids (108), limonoids/terpenoids (59), phenolic acids (49) and lower-molecular-weight phenolics (39). A. polystachya extract showed the most potent cytotoxic activity against Huh-7, DU-145 and MCF-7 cell lines (IC50 = 3, 3.5 and 13.4 µg mL−1, respectively), followed by M. azedarach, with no effect recorded for T. ciliata extract. Furthermore, both A. polystachya and M. azedarach extracts showed promising anti-virulence and antimicrobial activities, with A. polystachya being particularly active against MRSA. These two latter extracts could inhibit and disrupt the biofilm, formed by MRSA, at sub-lethal concentrations. Interestingly, the extracts inhibited hemolysin-α enzyme, thus protecting rabbit RBCs from lysis. A. polystachya extract reduced the pigmentation and catalase enzyme activity of tested pigmented strains better than M. azedarach at both tested sub-MICs. Consequently, susceptibility of the extract-treated cells to oxidant killing by 200 mM H2O2 increased, leading to faster killing of the cells within 120 min as compared to the extract-non-treated cells, likely due to the lower antioxidant-scavenging activity of cells exhibiting less staphyloxanthin production. Conclusion: These findings suggested that both A. polystachya and M. azedarach natural extracts are rich in bioactive compounds, mainly limonoids, phenolics and oxygenated triterpenoids, which can combat MRSA biofilm infections and could be considered as promising sources of therapeutic cytotoxic, antibiofilm and anti-virulence agents.

Antibiotic resistance rate of the Methicillin Resistant Staphylococcus aureus isolated from a university affiliated hospital in North Cyprus

Background: Over the past 20 years, studies have indicated that the increasing spread of methicillinresistant Staphylococcus aureus (MRSA) demonstrates the need for adequate information about their epidemiology. This study was conducted in order to investigate the resistance rate of MRSA which were isolated from the Near East University (NEU) Hospital, North Cyprus. Methods: MRSA was isolated and identified by using selective media and the Phoenix BD 100 system (software version 6.01A) was used for antimicrobial susceptibility testing and identification. The antimicrobial susceptibility results were determined according to the Clinical and Laboratory Standarts Institute (CLSI) and the resistance rates of MRSA isolates to antibiotics were examined retrospectively. Results: The highest number of samples were from the departments of chest disease (24%) followed by dermatology (21.3%) and cardiology (18.7%). Out of 75 MRSA strains,; 29.7% from blood, 25.3% from wound, 14.7% from nasal swabs, 10.7% from aspiration fluids, 9.3% from sputum, 6.7% were from urine, 4.0% from IV catheters culture samples. All strains of MRSA were 94.7% sensitive to vancomycin and teicoplanin. Conclusions: The obtained results revealed that preventative measures should be implemented in order to minimize the bacterial resistance to antibiotics. Bangladesh Journal of Medical Science Vol. 21(1) 2022 Page : 101-104

Comparative Study of Two-Dimensional (2D) vs. Three-Dimensional (3D) Organotypic Kertatinocyte-Fibroblast Skin Models for Staphylococcus aureus (MRSA) Infection

The invasion of skin tissue by Staphylococcus aureus is mediated by mechanisms that involve sequential breaching of the different stratified layers of the epidermis. Induction of cell death in keratinocytes is a measure of virulence and plays a crucial role in the infection progression. We established a 3D-organotypic keratinocyte-fibroblast co-culture model to evaluate whether a 3D-skin model is more effective in elucidating the differences in the induction of cell death by Methicillin-resistant Staphylococcus aureus (MRSA) than in comparison to 2D-HaCaT monolayers. We investigated the difference in adhesion, internalization, and the apoptotic index in HaCaT monolayers and our 3D-skin model using six strains of MRSA representing different clonal types, namely, ST8, ST30, ST59, ST22, ST45 and ST239. All the six strains exhibited internalization in HaCaT cells. Due to cell detachment, the invasion study was limited up to two and a half hours. TUNEL assay showed no significant difference in the cell death induced by the six MRSA strains in the HaCaT cells. Our 3D-skin model provided a better insight into the interactions between the MRSA strains and the human skin during the infection establishment as we could study the infection of MRSA in our skin model up to 48 h. Immunohistochemical staining together with TUNEL assay in the 3D-skin model showed co-localization of the bacteria with the apoptotic cells demonstrating the induction of apoptosis by the bacteria and revealed the variation in bacterial transmigration among the MRSA strains. The strain representing ST59 showed maximum internalization in HaCaT cells and the maximum cell death as measured by Apoptotic index in the 3D-skin model. Our results show that 3D-skin model might be more likely to imitate the physiological response of skin to MRSA infection than 2D-HaCaT monolayer keratinocyte cultures and will enhance our understanding of the difference in pathogenesis among different MRSA strains.

Clinical characteristics and outcome of neonates with neonatal mastitis: a hospital based study

Background: Neonatal mastitis is not an uncommon condition, mostly occurs due to Staphylococcus aureus (S. aureus), sometimes leading to breast abscess with detrimental effects.Methods: Our study was retrospective, hospital based observational study carried out at Government Medical College, Baramulla from August 2017 to August 2019, all cases with features of neonatal mastitis were included in the study and also admitted in hospital. Clinical and laboratory data along with demographic data was recorded and analysed.Results: 23 cases were included with age of presentation 8 to 28 days. Babies particularly male babies received breast massage (N=10), besides this pain (15) and redness (N=23) was most common clinical characteristics purulent discharge seen in 2 cases and 7 cases were febrile. Laboratory findings include decreased total leucocyte count (TLC) and positive C-reactive protein (CRP), pus culture from samples revealed S. aureus in 11 cases, coagulase-negative staphylococci (CONS) in 3 cases, E. coli in 2 cases and sterile in 7 cases. Most of cases were sensitive to penicillin (N=14) and in two cases were methicillin resistant S. aureus (MRSA) strains resistant to methicillin. All patients responded well to intravenous (IV) antibiotics while as 8 cases required (I and D), blood cultured showed growth in 19 cases while cerebrospinal fluid (CSF) analysis was sterile in all patients. Above all babies were discharged successfully without any complications.Conclusions: We concluded from our study that neonatal mastitis if treated early has better outcome rather than practicing misbeliefs like breast massage to express so called witch’s milk, in addition we conclude that neonatal mastitis is not an uncommon problem.

Novel Small-Molecule Hybrid-Antibacterial Agents against S. aureus and MRSA Strains

Ongoing resistance developments against antibiotics that also affect last-resort antibiotics require novel antibacterial compounds. Strategies to discover such novel structures have been dimerization or hybridization of known antibacterial agents. We found novel antibacterial agents by dimerization of indols and hybridization with carbazoles. They were obtained in a simple one-pot reaction as bisindole tetrahydrocarbazoles. Further oxidation led to bisindole carbazoles with varied substitutions of both the indole and the carbazole scaffold. Both the tetrahydrocarbazoles and the carbazoles have been evaluated in various S. aureus strains, including MRSA strains. Those 5-cyano substituted derivatives showed best activities as determined by MIC values. The tetrahydrocarbazoles partly exceed the activity of the carbazole compounds and thus the activity of the used standard antibiotics. Thus, promising lead compounds could be identified for further studies.

Staphylococcus aureus in poultry, with special emphasis on methicillin-resistant strain infection: A comprehensive review from one health perspective

Staphylococcus aureus is a Gram-positive coccus normally present on the skin and internal organs of animals, birds, and humans. Under certain conditions, S. aureus could produce septicemia and affection of the skin, joints, and heart, as well as sepsis and death. The pathogenicity of S. aureus is associated with the presence of some virulent surface proteins and the production of some virulent toxins and enzymes. This pathogen is considered one of the most important and worldwide foodborne causes as it is incriminated in most cases of food poisoning. The hazardous use of antibiotics in the veterinary field leads to the development of multidrug-resistant S. aureus strains that can be transmitted to humans. The incidence of methicillin-resistant S. aureus (MRSA) strains has increased globally. These resistant strains have been detected in live animals, poultry, and humans. In addition, retail animal products, especially those of avian origin, are considered the main source of MRSA strains that can be easily transmitted to humans. MRSA infection is regarded as nosocomial or occupational. Humans get infected with MRSA strains through improper handling or preparation of contaminated animals or poultry carcasses or improper cooking with contaminated meat. Live birds also can transmit MRSA to close-contact workers in poultry farms. Transmission of MRSA infection in hospitals is from an infected individual to a healthy one. Prevention and control of MRSA are based on the application of hygienic measures in farms as well as proper processing, handling, and cooking of retail poultry products. The cooperation between veterinary and human practitioners is a must to avoid the possibility of zoonotic transmission. Accordingly, this review focused on the sources and transmission of MRSA infection, virulence and resistance factors, incidence and prevalence in poultry and different products, antibiotic resistance, and prevention and control strategies.

Prevalence of MRSA and Antimicrobial Susceptibility Staphylococcus aureus in Clinical Samples in National Capital Region, India

Background: Infections caused by Staphylococci are frequently linked to indwelling medical equipment. These are extremely difficult to treat with antibiotics. In India, the prevalence of Methicillin-Resistant Staphylococcus aureus (MRSA) varies from 30 to 70%, resulting in high mortality, increased economic burden, and high treatment failure in tertiary care hospitals. Rapid and reliable identification of MRSA is critical for infection management and avoiding the needless use of antibiotics. Materials and Methods: This prospective study was carried out in the Department of Microbiology, Santosh Medical College, Ghaziabad, from the 1st of August 2020 to the 31st of January 2021. MRSA isolates were screened and confirmed using standard methods recommended by the Clinical and Laboratory Standards Institute (CLSI). Methicillin resistance, in Staphylococcus aureus strains, was evaluated using oxacillin/cefoxitin. The Kirby-Bauer disc diffusion technique was used to assess the antibiotic susceptibility pattern of all MRSA strains. Results: In this investigation, MRSA was identified in 29.4% of the 384 Staphylococcus aureus strains. When compared to females, men outnumbered females. Cefoxitin detects a greater amount of MRSA than oxacillin. In this investigation, the majority of MRSA was found in pus samples. Conclusion: MRSA prevalence is known to vary depending on geographical region, hospital type, investigated population, and technique of detection used. Given the clinical implications of MRSA infection and its fast transmission capability, MRSA strains must be monitored on a regular basis.

Antimicrobial Resistance Leading to Develop Livestock-Associated Methicillin-Resistant S. aureus, and Its Impact on Human, Animal, and Environment

The most important microbe in humans is Staphylococcus aureus, which has caused worldwide dispersion in both nosocomial and community settings. The impact of Gram-positive Staphylococcus Aureuson the host is extremely detrimental to illness development. The life form is noteworthy for its ability to receive anti-toxin protection from a variety of anti-toxin classes. The development and distribution of methicillin-resistant Staphylococcus Aureus (MRSA) strains, which are generally multi-drug resistant in clinics and, as a result, in the population, cause severe mortality and bleakness. The research of MRSA illness transmission has advanced since its underlying event, which necessitates a complete clinical approach to dealing with take on this microorganism. For long term use drug of choice is vancomycine nevertheless its efficacy has been put to the test by rise in opposition. More modern anti-MRSA anti-infection medicines have been approved for clinical usage in the last 10 years or so. The aim of this chapter is to offer related data on the genus Staphylococcus and the evolution of antibiotic resistance in addition a discussion of the most important antibiotic resistance mechanisms. Although they are notorious for causing anti-infection blockage, there is a constant need for exploring innovative MRSA antagonists from various sources, including plants, and assessing non-anti-toxin draws close.

Systematic Review: A Comparison between Vancomycin and Daptomycin for Sepsis Infection Antibiotic Therapy

BACKGROUND: Sepsis is a dangerous condition that threatens life because of immune system dysregulation caused by an infection resulting in organ failure. One of the most common resistant strain bacteria that can cause sepsis is Methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is the first-line therapy for treating sepsis infection caused by MRSA, but recently there have been some MRSA strains that are resistant to vancomycin therapy. AIM: This study aimed to review comparison between vancomycin and daptomycin for sepsis infection antibiotics therapy. MATERIALS AND METHODS: This research was a systematic review using three databases such as PubMed, ProQuest, and ScienceDirect. The journal articles included in this study were about randomized controlled trial (RCT) studies published from 2011 to 2020. RESULTS: This research included seven RCT studies, but none of them discuss the usage of daptomycin for sepsis treatment caused by MRSA. They discuss more the effect of dose, method of administration, and side effects of vancomycin therapy in relation to the outcome of the patient. CONCLUSIONS: Because of the lack of RCT articles that conducted experiments of daptomycin usage for sepsis treatment caused by MRSA infection, this research could not compare the effectiveness between vancomycin and daptomycin. However, from some case reports included in this research, there was evidence that the usage of daptomycin base after vancomycin treatment failure will cause another treatment failure.

Disinfectant and Antimicrobial Susceptibility Studies of Staphylococcus aureus Strains and ST398-MRSA and ST5-MRSA Strains from Swine Mandibular Lymph Node Tissue, Commercial Pork Sausage Meat and Swine Feces

Staphylococcus aureus (S. aureus) causes gastrointestinal illness worldwide. Disinfectants are used throughout the food chain for pathogenic bacteria control. We investigated S. aureus bioavailability in swine Mandibular lymph node tissue (MLT) and pork sausage meat (PSM), established susceptibility values for S. aureus to disinfectants, and determined the multilocus sequence type of MRSA strains. Antimicrobial and disinfectant susceptibility profiles were determined for 164 S. aureus strains isolated from swine feces (n = 63), MLT (n = 49) and PSM (n = 52). No antimicrobial resistance (AMR) was detected to daptomycin, nitrofurantoin, linezolid, and tigecycline, while high AMR prevalence was determined to erythromycin (50.6%), tylosin tartrate (42.7%), penicillin (72%), and tetracycline (68.9%). Methicillin-resistant S. aureus (MRSA) strains, ST398 (n = 6) and ST5 (n = 1), were found in the MLT and PSM, 4 MRSA in MLT and 3 MRSA strains in the PSM. About 17.5% of feces strains and 41.6% of MLT and PSM strains were resistant to chlorhexidine. All strains were susceptible to triclosan and benzalkonium chloride, with no cross-resistance between antimicrobials and disinfectants. Six MRSA strains had elevated susceptibilities to 18 disinfectants. The use of formaldehyde and tris(hydroxylmethyl)nitromethane in DC&R was not effective, which can add chemicals to the environment. Didecyldimethylammonium chloride and benzyldimethylhexadecylammonium chloride were equally effective disinfectants. ST398 and ST5 MRSA strains had elevated susceptibilities to 75% of the disinfectants tested. This study establishes susceptibility values for S. aureus strains from swine feces, mandibular lymph node tissue, and commercial pork sausage against 24 disinfectants. Since it was demonstrated that S. aureus and MRSA strains can be found deep within swine lymph node tissue, it may be beneficial for the consumer if raw swine lymph node tissue is not used in uncooked food products and pork sausage.