The rapid development of nanotechnology and its applications in medicine has provided the perfect solution against a wide range of different microbes, especially antibiotic-resistant ones. In this study, a one-step approach was used in preparing silver nanoparticles (AgNPs) by mixing silver nitrate with hot Hypericum perforatum (St. John’s wort) aqueous extract under high stirring to prevent agglomeration. The formation of silver nanoparticles was monitored by continuous measurement of the surface plasma resonance spectra (UV-VIS). The effect of St. John’s wort aqueous extract on the formation of silver nanoparticles was evaluated and fully characterized by using different physicochemical techniques. The obtained silver nanoparticles were spherical, monodisperse, face-centered cubic (fcc) crystal structures, and the size ranges between 20 to 40 nm. They were covered with a capping layer of organic compounds considered as a nano dimension protective layer that prevents agglomeration and sedimentation. AgNPs revealed antibacterial activity against both tested Gram-positive and Gram-negative bacterial strains causing the formation of 13–32 mm inhibition zones with MIC 6.25–12.5 µg/mL; Escherichia coli strains were resistant to tested AgNPs. The specific growth rate of S. aureus was significantly reduced due to tested AgNPs at concentrations ≥½ MIC. AgNPs did not affect wound migration in fibroblast cell lines compared to control. Our results highlighted the potential use of AgNPs capped with plant extracts in the pharmaceutical and food industries to control bacterial pathogens’ growth; however, further studies are required to confirm their wound healing capability and their health impact must be critically evaluated.

Nineteen aromatic nitro compounds were isolated from the culture broth of an Artic sea ice bacterium. Four of these compounds are new and six compounds are reported from a natural source for the first time. The new natural products showed weak antimicrobial and cytotoxic activities. 2-Nitro-4-(2′-nitroethenyl)-phenol was the most potent antimicrobial and cytotoxic substance. Some of the compounds exhibit plant growth modulating activities. Based on its biochemical properties and the 16S rRNA gene sequence, the producing strain can be described as a distinct species within the genus Salegentibacter.

Introduction: A high rate of infections with methicillin-resistant Staphylococcus aureus (MRSA) has been documented, in both hospital- (HA-MRSA) and community-acquired (CA-MRSA) diseases in Jordan. Erythromycin and clindamycin are considered treatments of choice. However, resistance to erythromycin with false susceptibility to clindamycin in vitro may lead to therapeutic failure. Hence, it is mandatory to study the prevalence of inducible resistance to macrolide-lincosamide-streptogramin B (iMLS_B) antibiotics conferred by erm genes in those bacteria. Methodology: S. aureus isolates were identified morphologically and biochemically, and MRSA were appraised using standard procedures. Induction in resistance to MLS_B antibiotics among MRSA isolates was detected phenotypically using the D-test, and the presence of erm genes was revealed by polymerase chain reaction (PCR). Results: Of 126 collected Staphylococcus isolates, 71 (56.3%) isolates were S. aureus, of which 55 (77.5%) were MRSA. A total of 43 (78.2%) MRSA-discordant isolates were resistant to erythromycin, of which 33 (76.7%) exhibited the iMLS_B (D-test positive), 2 (4.7%) the MS_B (D-test negative), and 8 (18.6%) the constitutive resistant (cMLS_B) phenotypes. Induction of clindamycin resistance was 1.6 times greater in CA-MRSA than in HA-MRSA. Furthermore, ermA and ermC were significantly prevalent in HA-MRSA and CA-MRSA, respectively. Conclusions: Continuous surveillance of the MLS_B resistance is important and required before the prescription of clindamycin to treat MRSA infections.

Context: Elettaria cardamomum (L.) Maton grains and Cinnamomum verum J. Presl barks are immensely consumed by Jordanian population as food flavoring and remedies in treating different disorders without awareness of their effect or dose toxicity. Aims: To evaluate the antibacterial, antioxidant and cytotoxic effects of essential oils (EOs) hydro-distilled from E. cardamomum grains and C. verum barks. Methods: Hydro-distillation was carried out using Clevenger apparatus; the EOs were analyzed using GC/MS, and their constituents were quantified using GC/FID. The antibacterial activity was determined by agar diffusion test and micro-broth dilution assay, while the antioxidant activity was evaluated by DPPH and ABTS scavenging assays. The cytotoxic activity was evaluated against the MDA-MB-231 breast cancer cell line. Results: E. cardamomum EO was most effective against Bacillus subtilis with MIC 3.75 µL/mL and exhibited antioxidant activity in DPPH assay with IC50 0.057 ±0.013 µL/mL (0.076 ±0.017 µL EO/µg Trolox®) but was ineffective in the ABTS test up to 5 µL/mL; 86.22% of its EO constituent are oxygenated monoterpenes with α-terpinyl acetate as the major component. Whilst C. verum EO was active against both tested Gram-positive and negative bacterial strains with MIC 1.25-5.00 µL/mL but was devoid of significant antioxidant activity up to 5 µL/mL; phenylpropanoids constituted 69.48% of its EO with E-cinnamaldehyde as the major component. Both EOs showed cytotoxic activity against the breast cancer cell line withIC50 0.14-0.46 µL/mL. Conclusions: The current results unveil the potential application of C. verum and E. cardamomum in complementary and alternative medicine as biosafe remedies besides their usage as flavoring and seasoning sources.