Antibacterial Screening of Bacterial Isolates Associated with Mangrove Soil from the Ngurah Rai Mangrove Forest Bali

In this study we reported cultivation of bacteria associated with mangrove soil from the Ngurah Rai Mangrove Forest, Bali. Mangrove soil samples were serially diluted using sterile artificial seawater, spread onto Starch Casein M agar and incubated at 28oC for 28 days. Cultivation of mangrove soil samples yielded 165 bacterial colonies with 68 isolates were selected and purified based on different morphology. Of these 68 isolates, 22 isolates displayed antibacterial activities ranging from weak to strong inhibition against at least one of four bacterial indicators namely Staphyloccocus aureus, Streptococus mutans, Escherichia coli and Klebsiella pneumoniae using perpendicular streak method. Overall, 19 out of 22 bacteria isolates displayed weak antibacterial potential and two isolates exhibited moderate antibacterial activity. The isolate SA4 was the only bacterium with strong antibacterial potential with measured clear distance ≥ 10 mm against the four bacterial isolates. Sequence analysis based on 16S rRNA gene fragment assigned the isolate SA4 as Bacillus subtilis strain BIL/BS-168. Overall, this study confirmed the untapped potential of antibacterial activities from bacteria associated with mangrove soil.

429. Infection Prevention During Use of a Warm Zone Model in Cohort Patient Care Locations during the COVID-19 Pandemic

Background The COVID-19 pandemic required hospitals to care for influxes of patients in cohort locations during critical shortages of personal protective equipment (PPE). Safety zones can be used to protect healthcare workers caring for patients with infectious pathogens. During the COVID-19 pandemic, our hospital developed a Warm Zone model (WZM) to streamline the care of patients with COVID. We established specific areas in our COVID cohort units where staff were permitted to bridge between rooms without doffing gowns, but still doffing gloves and performing hand hygiene between patients. We recognized that a WZM could inadvertently increase risk of nosocomial transmission of pathogens if gowns acted as fomites. For this reason, patients with known infectious pathogens were excluded from the WZM. To measure for unintended harmful consequences of the WZM, our Infection Prevention (IP) department performed surveillance for hospital onset (HO) Clostridioides difficile (CDI), Carbapenem-resistant enterobacteriaceae (CRE) and Methicillin-resistant Staphyloccocus aureus (MRSA) bloodstream infections on units that implemented the WZM. Methods Two intensive care units and 3 wards where COVID positive patients were cohorted were included in surveillance. The timeframe for this analysis was 7/1/2020 - 3/31/2021. An electronic surveillance system was used to measure HO infections. The National Healthcare Surveillance Network (NHSN) LabID definitions were used when determining HO CDI and MRSA bloodstream infections (BSI). Results During the study period, there were no HO CRE, 1 HO CDI, and 2 HO MRSA BSI in cohort units. There was no evidence to suggest that the HO CDI or HO MRSA BSI were associated with use of a WZM. During this time period, there were 14 cases of community onset (CO) CDI, 2 cases of CO MRSA BSI, and one CO CRE. Conclusion During use of a WZM in COVID cohort units, IP did not identify significant increase in HO CDI, CRE, or MRSA BSI compared to non-cohort units. We were limited in our ability to measure acquisition of pathogens because active surveillance screening for colonization was not performed. However, we were able to safely employ a WZM to streamline patient care in COVID cohort areas without evidence of causing nosocomial infections via patient-to-patient transmission. Disclosures All Authors: No reported disclosures

Comparative study on the phytochemical composition and antibacterial activity of the essential oil of Diphasia klaineana stems at pre-flowering and fruit set

The phytochemical composition and antibacterial activity of the essential oils of Diphasia klaineana at different developmental stages (pre-flowering and fruit set) were reported. The essential oils were extracted by continuous hydro distillation and their antibacterial activities were tested against Staphyloccocus aureus ATCC 25923. The yield of oil (w/w %) of stems in different stages was in the order: pre-flowering (0.21 %) > fruit set (0.07 %). GC and GC/MS were analyzed the essential oils composition. In total, 35 and 34 constituents were identified and quantified in the mentioned samples, respectively. Monoterpene hydrocarbons were the main group of compounds in the stems during preflowering (42.40 %) and fruit set (56.15 %). Major compounds at pre-flowering were β-elemol, sabinene, guaiol and terpinen-4-ol. The antibacterial effect of essential oils was estimated by the disk diffusion method using Müller–Hinton agar and the measurement of diameters of inhibition zones. The bioassay results showed some variations between the two tested oils in their inhibitory activity against the tested bacteria at 10 µL. The essential oils from Diphasia klaineana stems at pre-flowering exhibited potent antibacterial activity against Staphyloccocus aureus ATCC 25923, with a minimum inhibitory concentration (MIC) value of 25 mg/mL, while the stems essential oil at fruit set had no activity

Action of methicillin on the "in vitro" growth of bacteria Staphyloccocus aureus methicillin-resistance previously treated with homeopathic dilutions

Background: Methicillin-resistant Staphylococcus aureus (MRSA) causes nosocomial infections, and it has been considered as a worldwide epidemic. The medical system seeks new strategies to fight against MRSA that do not generate resistant strains to antibiotics. Homeopathy has been explored as one of these new strategies, which may play a pivotal role. In this context, we conducted studies on the action of homeopathy on growth of MRSA bacteria in vitro. The results showed a decrease in growth of bacterial strains with homeopathic dilutions of Belladonna and the S. aureus nosode. Now we have proposed to evaluate the minimum inhibitory concentration (MIC) of the antibiotic methicillin or oxacillin on S. aureus MRSA, previously incubated with the homeopathic dilutions of Belladonna or S. aureus nosode. Methods: The Clinical and Laboratory Standards Institute (CLSI 2014) standards were followed according to the determination of the minimum inhibitory concentration (MIC). In 5 mL of cation adjusted Mueller Hinton (CAMH) broth, it was added 420 µl of 30% alcohol or Belladonna and S. aureus’ nosode in the dilutions 6cH, 12cH and 30cH. Then a 20µl of bacterial suspension of MRSA was added to 0.5 McFarland range and diluted to 1/10. The tubes were incubated in an oven at 37⁰C for three hours. The plates were previously prepared with 50µl per well of serial dilutions of the antibiotic oxacillin in concentrations of 128 µg/mL to 0.5 µg/mL in CAMH broth. Then it was added 50 µl per well of bacterial cultures. The plate was incubated in an oven at 37⁰C for 24 hours and the bacterial growth measured in a spectrophotometer 600nm. The point of the MIC of oxacillin for S. aureus is 4 µg/mL, according to CLSI 2014 criteria. Results: We did not observe the total inhibition of bacterial growth when incubated with the homeopathic medicine and oxacillin. In evaluation of the spectrophotometer culture, we observed significant changes in the growth, compared to the control (30% alcohol). Cultures treated with Belladonna 6cH and the antibiotic in the dilution 4 µg/mL showed a decrease of 40% of the growth, while in the 30cH the drop was of 75%. Cultures treated with the S. aureus nosode 30cH and the antibiotic at 4 µg/mL dilution, showed a decrease of 60% in bacterial growth in vitro. Conclusion: The results suggest that bacterial cultures the S. aureus (MRSA) incubated with the homeopathic medicines would be more susceptible to oxacillin’s antimicrobial action.

Quantitative Phytochemical Analysis Reveals Significant Antibiofilm Activity in Pleione maculata, an Endangered Medicinal Orchid

Pleione maculata has no scientific reports on quantitative phytochemical and antibiofilm activity till date. The objective of the study was to quantify and determine medicinally important bioactivity in P. maculata and analyse its anti-biofilm activity against clinical isolates Staphyloccocus aureus, Klebsiella pneumoniae and Proteus mirabilis. P. maculata exhibited the highest Total Antioxidant Capacity (TAC) about 193.98 ± 0.1 mg, highest Total Phenolic Content (TPC) at 552± 0.0 mg and Total Flavonoid Content (TFC) were observed highest at 879.5 ± 0.2 mg. The acetone and ethyl acetate extracts of P. maculata pseudobulb showed distinct and significant zone of inhibition (ZOI) against drug-resistant S.aureus about 16 ± 0.00 mm (MIC 0.875 mg/mL), ZOI of acetonitrile pseudobulb extract against P. mirabilis was 15.33 ± 0.4mm (MIC 1 mg/mL), ZOI of acetonitrile extracts of leaves and stem, ethyl acetate extract of pseudobulb was 12 ± 0.0mm, 12 ± 01.4mm, 12 ± 2.8mm against K. pneumoniae (MIC 1.8 mg/mL, 0.68 mg/mL and 3 mg/mL). Acetonitrile extract of pseudobulbs exhibited the highest Minimum Biofilm Inhibition concentration (MBIC) at 0.25 mg/mL against S. aureus, water root extract inhibited attachment of K. pneumoniae with lowest MBIC value 0.093 mg/mL, water and acetone extract of leaves inhibited cell attachment of P. mirabilis at lowest MBIC 0.117 and 0.171 mg/mL. The UV-VIS absorption band of P. maculata extracts ranges from 204-665 nm indicating the presence of phenolic and flavonoid compounds. The study indicates the potentiality of P. maculata as a rich source of medicinal active compounds as an antibiofilm agent against antibiotic-resistant clinical isolates.

AKTIVITAS ANTIBAKTERI EKSTRAK ETANOL DAUN PANDAN WANGI (Pandanus amaryfolius) TERHADAP Staphylococcus aureus

Pandan wangi (Pandanus amaryllifolius ) yang lazim digunakan sebagai pewangi dan pewarna makanan ternyata berpotensi memiliki aktivitas antibakteri. Bakteri Staphylococcus aureus merupakan bakteri yang dapat menyebabkan infeksi.Tujuan penelitian ini adalah untuk mengetahui aktivitas daun pandan wangi sebagai antibakteri Staphylococcus aureus, dengan mengetahui Konsentrasi Hambat Minimum (KHM) dan Konsentrasi Bunuh Minimum (KBM) serta untuk mengetahui senyawa kimia apa saja yang terkandung dalam daun pandan wangi. Ekstrak etanol daun pandan wangi diperoleh melalui metode maserasi menggunakan pelarut alkohol 70%. Penelitian ini merupakan penelitian ekperimental dengan menggunakan post test only control group design,dengan menggunakan metode dilusi. Hasil penelitian menujukan bahwa nilai KHM pada konsentrasi 40% sudah mampu menghambat pertumbuhan bakteri staphylococcus aureus. Konsentrasi Bunuh Minimum (KBM) ekstrak daun pandan wangi pada bakteri staphyloccocus aureus wangi belum dapat ditentukan nilainya karena pada konsentrasi tertinggi 60% masih terdapat pertumbuhan koloni rata-rata sebanyak 27 koloni.

Investigations on Corrosion Inhibitory Effect of Newly Quinoline Derivative on Mild Steel in HCl Solution Complemented with Antibacterial Studies

This study analyzed the corrosion inhibitory effects and the antibacterial action of the quinoline derivative, namely N'-(2-hydroxybenzylidene)-2-(quinolin-8-yloxy)acetohydrazide (NHQA). NHQA prevention of corrosion behavior was investigated using weight loss experiments on mild steel coupons in hydrochloric acid. Weight loss tests achieved improved inhibition performance for NHQA, and the high inhibitor efficiency was reached at 303 K, of 93.4 percent at 500 ppm NHQA. Moreover, the effect of immersion time on carbon steel corrosion was investigated using strategies for weight loss. The NHQA mechanism for corrosion inhibition was also examined. These findings confirm that the NHQA molecules can be used in industrial applications as a possible corrosion inhibitor. In an aqueous solution, the synthesized compound (NHQA) can also be used as an antimicrobial agent. The microbial inhibitive efficacy of NHQA against Gram-positive (Staphyloccocus aureus) and Gram-negative bacteria (Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae, and Pseudomonas aeruginosa) was evaluated employee a disc diffusion technique. NHQA has considerable inhibition efficacy toward all investigated bacteria.

Actividad antimicrobiana del extracto hidroalcohólico de Calendula officinalis L.

La búsqueda de productos naturales, con determinadas funciones como aditivos alimentarios, son de gran interés investigativo por su proyección industrial. Por esta razón, el presente documento muestra los resultados de un estudio exploratorio sobre la actividad antibacteriana de un extracto hidroalcohólico de Calendula officinalis L., el cual se caracterizó mediante análisis fitoquímico, espectroscopía Infrarroja-Attenuated Total Reflection (IR-ATR), y cromatografía de gases acoplada a masas (CG-MS). El poder antimicrobiano se determinó sobre Pseudomona aeruginosa, Staphyloccocus aureus, y Candida albicans. Finalmente, se realizó una aplicación sobre fresa (Fragaria chiloensis L.), con el fin de observar el efecto sobre la vida útil del fruto, esto en las condiciones ambientales de temperatura 20 °C y humedad relativa 70%. Los resultados muestran que el extracto hidroalcohólico es una mezcla de diversos compuestos químicos, con buenas propiedades como biocompuestos activos. Finalmente se evidencia la presencia de taninos, carotenoides y compuestos fenólicos, entre otros, los cuales, de acuerdo con el estudio de actividad antimicrobiana, mejoraron la vida útil de la F. chiloensis.

A Chimeric Cationic Peptide Composed of Human β-Defensin 3 and Human β-Defensin 4 Exhibits Improved Antibacterial Activity and Salt Resistance

Human beta-defensins (hBDs) play an important role in the host defense against various microbes, showing different levels of antibacterial activity and salt resistance in vitro. It is of interest to investigate whether can chimeric hBD analogs enhanced antibacterial activity and salt resistance. In this study, we designed a chimeric human defensin, named H4, by combining sequences of human beta-defensin-3 (hBD-3) and human beta-defensin-4 (hBD-4), then evaluated its antibacterial activity, salt resistance, and cytotoxic effects. The result showed that the antibacterial activity of H4 against most tested strains, including Klebsiella pneumonia, Enterococcus faecalis, Staphyloccocus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, and Acinetobacter baumannii was significantly improved compared to that of hBD-3 and hBD-4. Notably, H4 exhibited significantly better antibacterial activity against multidrug resistant isolate A. baumannii MDR-ZJ06 than commonly used antibiotics. Chimeric H4 still showed more than 80% antibacterial activity at high salt concentration (150 μM), which proves its good salt tolerance. The cytotoxic effect assay showed that the toxicity of H4 to Hela, Vero, A549 cells and erythrocytes at a low dose (<10 μg/ml) was similar to that of hBD-3 and hBD-4. In conclusion, given its broad spectrum of antibacterial activity and high salt resistance, chimeric H4 could serve as a promising template for new therapeutic antimicrobial agents.