The potential usage of Caatinga natural products against multi-drug-resistant bacteria.

New sources of antibacterial drugs have become urgent with increasing bacterial resistance. Medicinal plants are attractive sources for antimicrobial compounds with fewer side effects and cheaper obtention. Brazil contains six biomes, including Caatinga, a semi-arid tropical vegetation exclusively from Brazil that contains over thousand vascular plant species. This review presents the potential of using Caatinga plant products to treat multidrug-resistant bacteria. This review used the keywords of antimicrobial resistance, resistance profile, multidrug resistance, Caatinga biome, and pathogenic bacteria to search in Scientific Electronic Library Online, the U.S. National Library of Medicine, and Google Scholar. Plant species as Schinopsis brasiliensis Engl., Annona vepretorum Mart., Croton pulegioides Baill., Myracrondruon urundeuva Allemo, Cereus jamacaru DC., Opuntia ficus-indica L., Bauhinia forficata L., Eucalyptus globulus, Croton sonderianus Muell. Arg., Campomanesia pubescens, and Abarema cochliacarpos showed bacteriostatic activity. Encholirium spectabile Mart., Hymenaea courbaril L., Neoglaziovia variegata Mez, Selaginella convoluta Spring, Encholirium spectabile Mart., Bromelia laciniosa Mart., Hymenaea martiana, Commiphora leptophloeos, and Mimosa tenuiflora presented bactericidal activity. Those extracts inhibited clinical-importance bacteria, such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Therefore, Caatinga biome plants are a valuable source of active biomolecules against pathogenic bacteria, and their therapeutic potential must be further explored.

Treating Multi-Drug-Resistant Bacterial Infections by Functionalized Nano-Bismuth Sulfide through the Synergy of Immunotherapy and Bacteria-Sensitive Phototherapy.

Owing to its flexibility and high treatment efficiency, phototherapy is rapidly emerging for treating bacteria-induced diseases, but how to improve the sensitivity of bacteria to reactive oxygen species (ROS) and heat simultaneously to kill bacteria under mild conditions is still a challenge. Herein, we designed a NIR light catalyst (Bi2S3-S-nitrosothiol-acetylcholine (BSNA)) by transforming •O2- into peroxynitrite in situ, which can enhance the bacterial sensibility to ROS and heat and kill bacteria under a mild temperature. The transformed peroxynitrite in situ possessed a stronger ability to penetrate cell membranes and antioxidant capacity. The BSNA nanoparticles (NPs) inhibited the bacterial glucose metabolic process through down-regulated xerC/xerD expression and disrupted the HSP70/HSP90 secondary structure through nitrifying TYR179. Additionally, the synergistic effect of the designed BSNA and clinical antibiotics increased the antibacterial activity. In the case of tetracycline-class antibiotics, BSNA NPs induced phenolic hydroxyl group structure changes and inhibited the interaction between tetracycline and targeted t-RNA recombinant protein. Besides, BSNA stimulated production of more CD8+ T cells and reduced common complications in peritonitis, which provided immunotherapy activity. The targeted and anti-infective effect of BSNA suggested that we propose a nanotherapeutic strategy to achieve more efficient synergistic therapy under mild temperatures.

Chemical Composition and Synergistic Potential of Mentha pulegium L. and Artemisia herba alba Asso. Essential Oils and Antibiotic against Multi-Drug Resistant Bacteria.

The essential oils were obtained by hydrodistillation from aerial parts of Mentha pulegium L. (M. pulegium L.) and Artemisia herba alba (A. herba alba) Asso. and analyzed by gas chromatography-flame ionization detector chromatograpy (GC-FID) and gaz chromatography-mass spectrometry (GC-MS). The antibacterial activities of the oils were determined by the disk diffusion method and a microdilution broth assay against six bacteria stains. The combinations of these essential oils with antibiotics were evaluated against two multi-drug-resistant bacteria strains: imipenem-resistant Acinetobacter baumannii (IRAB S3310) and methicillin-resistant Staphylococcus aureus (MRSA S19). The chemical analysis of M. pulegium essential oil revealed the presence of pulegone (74.8%) and neoisomenthol (10.0%). A. herba alba essential oil was characterized by camphor (32.0%), α-thujone (13.7%), 1,8-cineole (9.8%), ß-thujone (5.0%), bornéol (3.8%), camphene (3.6%), and p-cymene (2.1%). All strains tested except Pseudomonas aeruginosa were susceptible to these oils. The combinations of essential oils with antibiotics exerted synergism, antagonism, or indifferent effects. The best effect was observed with A. herba alba essential oil in association with cefoxitin (CX) against MRSA S19. However, for IRAB S3310, the strongest synergistic effect was observed with M. pulegium in association with amikacin (AK). This study demonstrated that M. pulegium and A. herba alba essential oils have antibacterial activities which could be potentiated by antibiotics especially in the case of IRAB S3310.

Clinical Efficacy of Tanreqing Injection Combined with Western Medicine in Treatment of Pneumonia Caused by Multi-drug Resistant Bacteria in Elderly Patients / 中国实验方剂学杂志

Objective:To observe the clinical effect of Tanreqing injection combined with western medicine on pneumonia caused by multi-drug resistant bacteria （MDRB） in elderly patients. Method:A total of 140 MDRB-induced pneumonia inpatients with the syndrome of phlegm-heat obstructing lung in the intensive care unit （ICU） of Dalian Hospital of Traditional Chinese Medicine from December 2018 to December 2020 were divided into an observation group （70 cases） and a control group （70 cases）） according to the random number table method. The patients in the control group received conventional treatment by western medicine， and those in the observation group received conventional treatment by western medicine combined with Tanreqing injection. The course of treatment was 7 days. The main efficacy indexes of the two groups before and after treatment were recorded，including the total clinical efficacy of traditional Chinese medicine （TCM） syndrome，total TCM syndrome score，clinical pulmonary infection score （CPIS）， and the clearance rate of MDRB. Secondary efficacy indexes included temperature recovery and cough remission time，procalcitonin （PCT），C-reactive protein （CRP），white blood cell count （WBC），interleukin-6 （IL-6），interleukin-8 （IL-8）， and oxygen partial pressure （PO₂）. Result:The total effective rates of the observation group and the control group were 90.00% （63/70） and 75.70% （53/70），respectively，and the observation group had superior curative efficacy （<italic>Z</italic>=-2.147，<italic>P</italic><0.05）. After treatment，CPIS and total TCM syndrome scores in both groups decreased compared with those before treatment，and the decrease was more significant in the observation group （<italic>P</italic><0.01）. The clearance rate of MDRB in the observation group was 67.1% （47/70），superior to 48.6% （34/70） in the control group （<italic>χ</italic>²=4.951，<italic>P</italic><0.05）. The temperature recovery and cough remission time in the observation group was shorter than that in the control group （<italic>P</italic><0.01）. After treatment，the levels of PCT，CRP，WBC，IL-6， and IL-8 in both groups were reduced compared with those before treatment，while the levels of PO₂ increased （<italic>P</italic><0.01）. The improvement of various inflammatory indexes and the PO₂ level in the observation group was better than that in the control group （<italic>P</italic><0.01）. Conclusion:The clinical efficacy of Tanreqing injection combined with western medicine in the treatment of MDRB-induced pneumonia in elderly patients is significant，which can control infection，reduce inflammatory damage，improve the clearance rate of MDRB and PO₂，and alleviate clinical symptoms. It is worthy of clinical application.

Anti-bacterial activity of chitosan loaded plant essential oil against multi drug resistant K. pneumoniae.

The development of antibiotic resistant in K. pneumoniae is an emerging thread worldwide due to the poor antimicrobial drugs. To overcome this issue, researchers are focused on plant material and their essential oils to fight against multi drug resistant bacteria. In this context, the current study was concentrated in medicinal plant of guva leaves and their essential oils to combat multi drug resistant bacterial infections. The essential oils were successfully screened and confirmed by HRLC-MS analysis. The anti-bacterial ability of the compounds were loaded into the chitosan nanoparticles and proved by FT-IR analysis. In addition, the chitosan loaded essential oils morphology was compared with chitosan alone in SEM analysis and suggested that the material was loaded successfully. Further, the anti-bacterial ability of the chitosan loaded essential oils were primarily confirmed by agar well diffusion method. At the 100 µg/mL of lowest concentration of chitosan loaded essential oils, the multi-drug resistant K. pneumoniae was inhibited with 96% and confirmed by minimum inhibition concentration experiment. Hence, all the experiments were proved that the essential oils were successfully loaded into the chitosan nanoparticles, and it has more anti-bacterial activity against multi-drug resistant K. pneumoniae.

Novel Silver-Platinum Nanoparticles for Anticancer and Antimicrobial Applications.

BACKGROUND: Cancer is a disease with an enormous worldwide impact. One of the fatal complications in cancer patients are bacterial opportunistic infections. The use of chemotherapeutic drugs made cancer remission more frequent and prolonged patient survival, but, increased the risk of infections. PURPOSE: Address the current problem with growing pandemic cancer and considering high risks of complications with bacterial infections, the present study synthesized novel dendritic assembly of silver (Ag)-platinum (Pt) nanoparticles. METHODS: Nanoparticles were characterized by TEM analysis, and the composition was confirmed by EDX. Bacterial studies were performed for Gram-positive Staphylococcus aureus, Gram-negative Pseudomonas aeruginosa and Gram-negative multi-drug resistant Escherichia coli. Cell experiments were performed with two different cancer cell lines, glioblastoma and melanoma to determine anticancer activity. Finally, cytotoxicity with fibroblast was tested. RESULTS: The TEM analysis of silver-platinum (AgPt) nanoparticles showed dendrimer shape nanoparticles with a mean size of 42 ± 11nm. Elemental composition was analyzed by EDX, confirming the presence of both Ag and Pt metals. The synthesized nanoparticles significantly inhibited the growth of medically important pathogenic, Gram-positive Staphylococcus aureus, Gram-negative Pseudomonas aeruginosa and Gram-negative multi-drug resistant Escherichia coli. Bactericidal effect of AgPt nanoparticles had greater effectiveness than silver nanoparticles. MTS assay revealed a selective and dose-dependent anticancer activity of AgPt nanoparticles over cancer cell lines glioblastoma and melanoma in the 10-250 µg/mL concentration range. Cytotoxicity experiments with fibroblast cells showed no side effects of nanoparticles against healthy cells at a range of concentrations from 10-50 µg/mL. CONCLUSION: The newly synthesized AgPt nanoparticles have a promising future as a potent anticancer agent with antibacterial properties.

Light-Activatable Synergistic Therapy of Drug-Resistant Bacteria-Infected Cutaneous Chronic Wounds and Nonhealing Keratitis by Cupriferous Hollow Nanoshells.

Due to the inability to spontaneously heal and vulnerability to bacterial infection, diabetic patients are frustrated by unexpected epithelium injuries in daily life. Notably, a drug-resistant bacterial infection may result in a long-term impact to the natural function of damaged organs. It is imperative to develop strategies that promote injury recovery and eradicate drug-resistant infection simultaneously. Here, we present a composite structured cupriferous hollow nanoshell (AuAgCu2O NS) that consists of a hollow gold-silver (AuAg) core and Cu2O shell as a photothermal therapeutic agent for a cutaneous chronic wound and nonhealing keratitis with drug-resistant bacterial infection. The controllable photothermal therapeutic effect and released silver ion from the hollow AuAg core possess a synergistic effect to eradicate multi-drug-resistant bacteria, including extended-spectrum ß-lactamase Escherichia coli (ESBL E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). Meanwhile, the released copper ion from the Cu2O shell could expedite endothelial cell angiogenesis and fibroblast cell migration, thus boosting wound-healing effects. In both infection-complicated disease models, the ophthalmic clinical score, wound closure rates, and histopathology analysis demonstrate that the AuAgCu2O NSs could facilitate the re-epithelialization at the wound area and eliminate the complicated bacterial infection from diabetic mice. A primary signal path involved in the promoted healing effect was further illustrated by comprehensive assays of immunohistochemical evaluation, Western blot, and quantitative polymerase chain reaction. Taken together, our AuAgCu2O NSs are shown to be potent candidates for clinical utilization in the treatment of diabetic epithelium injuries.

The Effect of Ten Essential Oils on Several Cutaneous Drug-Resistant Microorganisms and Their Cyto/Genotoxic and Antioxidant Properties.

In this study, we determined the antimicrobial activity of ten essential oils (EOs)-oregano, thyme, clove, arborvitae, cassia, lemongrass, melaleuca, eucalyptus, lavender, and clary sage-against drug-resistant microorganisms previously isolated from patients with skin infections. The essential oil compositions were determined using gas chromatography coupled to mass spectrometry (GC/MS). The assayed bacteria included Pseudomonas aeruginosa, Proteus vulgaris, Citrobacter koseri, and Klebsiella pneumoniae. Two drug-resistant yeasts (Candida albicans and Candida parapsilosis) were also involved in our survey. Oregano, thyme, cassia, lemongrass and arborvitae showed very strong antibacterial and antifungal activity against all tested strains. These results show that these essential oils may be effective in preventing the growth of the drug-resistant microorganisms responsible for wound infections. In this study, the genotoxic effects of tested essential oils on healthy human keratinocytes HaCaT were evaluated using the comet assay for the first time. These results revealed that none of the essential oils induced significant DNA damage in vitro after 24 h. Moreover, the treatment of HaCaT cells with essential oils increased the total antioxidant status (TAS) level. The obtained results indicate that EOs could be used as a potential source of safe and potent natural antimicrobial and antioxidant agents in the pharmaceutical and food industries.

Prevalence of infectious multi-drug resistant bacteria isolated from immunocompromised patients in Tunisia.

OBJECTIVES: A retrospective study was conducted in the Bone Marrow Transplant Center of Tunisia during a period of 10 years (from 2002 to 2011) in order to report the prevalence of infectious multi-drug resistant bacteria. METHODS: Bacterial identification was carried on the basis of biochemical characteristics and API identification systems. Antibiotic susceptibility was tested by disc diffusion method on Muller-Hinton agar. RESULTS: During the study period, 34.5% of 142 Klebsiella pneumoniae strains and 11.46% of 218 Escherichia coli strains were extended-spectrum beta-lactamase (ESBL) producers. Also, 32.8% of 210 strains of Pseudomonas aeruginosa were imipenem and/or ceftazidime resistant and 20.75% of 106 strains of Staphylococcus aureus were methicillin resistant. A rising trend was observed for the prevalence of the selected multidrug resistant bacteria. CONCLUSION: These findings may have important clinical implications in prophylaxis and selection of antibiotic treatment. Continuous surveillance is needed, especially for onco-hematological patients.

Platelet-rich plasma as an additional therapeutic option for infected wounds with multi-drug resistant bacteria: in vitro antibacterial activity study.

PURPOSE: Infected wounds, such as diabetic foot infections, are mostly polymicrobial and microorganisms have high resistance rates to antimicrobials. Infected wounds in diabetic patients have high cost, morbidity, and mortality rates. Based on these facts, there is a need for supportive localized treatment options such as platelet-rich plasma (PRP) implementations. Demonstrating the in vitro antimicrobial effect, our aim was to lead up to clinical trials of localized PRP implementations in infected wounds such as diabetic foot infections. In this study, we aimed to demonstrate the in vitro antibacterial activity of PRP against methicilin-resistant Staphylococcus aureus (MRSA) and three more multi-drug resistant bacteria species that are important and hard-to-treat in wound infections. MATERIALS AND METHODS: In vitro antimicrobial activity of autologous PRP, platelet-poor plasma (PPP), and phosphate-buffered saline (PBS) on methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., extended spectrum beta lactamase producing Klebsiella pneumoniae, and carbapenem-resistant Pseudomonas aeruginosa was compared by assessment of bacterial growth on agar plates and antimicrobial susceptibility test results. RESULTS: When compared to control group, PRP and PPP significantly suppressed bacterial growth of MRSA, K. pneumoniae, and P. aeruginosa at 1st, 2nd, 5th, and 10th hours of incubation (p < 0.05). VRE was the only bacteria that PRP and PPP showed limited activity against. When compared to PPP, PRP showed higher activity against MRSA, K. pneumoniae, and P. aeruginosa. However, the differences between PRP and PPP were statistically significant only against MRSA and P. aeruginosa at the first hour of incubation. CONCLUSIONS: Emerging PRP and other platelet-derived products seem to be promising alternative tools besides antibiotic treatment, debridement, negative pressure wound therapy, hyperbaric oxygen therapy, and other treatment options for treating diabetic foot infections.

High Potency of Melaleuca alternifolia Essential Oil against Multi-Drug Resistant Gram-Negative Bacteria and Methicillin-Resistant Staphylococcus aureus.

PURPOSE: Herein, an extended investigation of Tea tree oil (TTO) against a number of multi-drug resistant (MDR) microorganisms in liquid and vapor phases is reported. METHODS: The activity of TTO was tested against methicillin-sensitive Staphylococcus aureus (MSSA), Escherichia coli, and clinical strains of methicillin-resistant S. aureus (MRSA), extended-spectrum beta lactamases producer carbapenem-sensitive Klebsiella pneumoniae (ESBL-CS-Kp), carbapenem-resistant K. pneumoniae (CR-Kp), Acinetobacter baumannii (CR-Ab), and Pseudomonas aeruginosa (CR-Pa). Minimal inhibitory/bactericidal concentrations (MIC/MBCs) and synergistic activity between TTO and different antimicrobials were determined. In the vapor assay (VP), TTO-impregnated discs were placed on the lid of a petri dish and incubated for 24 h at 37 °C. RESULTS: TTO showed a potent bactericidal activity against all the tested microorganisms. TTO in combination with each reference antimicrobial showed a high level of synergism at sub-inhibitory concentrations, particularly with oxacillin (OXA) against MRSA. The VP assay showed high activity of TTO against CR-Ab. CONCLUSION: Evaluation of in-vitro activity clearly indicated TTO as a potential effective antimicrobial treatment either alone or in association with known drugs against MDR. Therefore, TTO could represent the basis for a possible role in non-conventional regimens against S. aureus and Gram-negative MDR. TTO in VP might represent a promising option for local therapy of pneumonia caused by CR-Ab.

Antimicrobial activity and drug-resistant reverse of 6 traditional Chinese medicines against multidrug resistant bacteria in vitro / 国际检验医学杂志

Objective To filter the traditional Chinese medicine with strong antibacterial activity and effects of reversing drug resistance of bacteria for providing new ideas for the treatment of multi-drug resistant bacteria infection.Methods Six kinds of antibacterial Chinese traditional medicines commonly used in clinic treatment as Radix Paeoniae Rubra,Indigo Naturalis,Galla Chinensis,Flos Chrysanthemi Indici,Herba Hout-tuyniae,and Berberine were used in this study.After preparation of the extract using decocting method,bacte-riostatic effects of these six kinds of Chinese medicine on multiple resistant bacteria were detected by double dilution method.To evaluate the effects of Chinese medicines on reversing drug resistance of multi-drug resist-ant bacteria,minimum inhibitory concentrations for multi-drug resistant bacteria and the original strain were detected by K-B method and calculated the difference of the bacterial inhibition rings.Results T he six kinds of traditional Chinese medicines had different degrees of inhibitory effects on MDR-AB and MDR-PA,and the bacteriostatic effect sequence were Galla Chinensis,Herba Houttuyniae,Flos Chrysanthemi Indici,Radix Pae-oniae Rubra,Indigo Naturalis,and Berberine.The bacteriostatic titer of Galla Chinensis on MDR-AB and MDR-PA was 512-1 024,whose antibacterial activity was the strongest in the six antibacterial Chinese tradi-tional medicines.Galla chinensis and Berberine had significant effects on reversing drug resistance of MDR-AB MDR-PA(P<0.05),but the difference value of inhibition zone diameters before and after reversing were less than 3 mm.Conclusion Radix Paeoniae Rubra,Indigo Naturalis,Galla Chinensis,Flos Chrysanthemi Indici, Herba Houttuyniae,and Berberine could inhibit MDR-AB and MDR-PA in different degrees,in which Galla Chinensis was the most effective antibacterial Chinese Medicine.Ggalla chinensis and Berberine could reverse drug resistance of MDR-AB and MDR-PA to some extent.

Reversal of resistance in bacteria underlies synergistic effect of essential oils with conventional antibiotics.

The pervasive of bacterial resistance earnestly threaten the prevention and the treatment of infectious diseases. Therefore, scientific communities take precedence over development of new antimicrobial agents. The aim of the study was to determine antimicrobial potency of three North-African essential oils Pituranthos chloranthus, Teucruim ramosissimum and Pistacia lentiscus individually, and in combination with antibiotics, to inhibit the growth of highly resistant clinical pathogen. Bacteria clinically isolated from patients, subsequently, challenged to a panel of drugs to determine the antibiotic-resistance profiles. Drugs displaying clinically irrelevant CMI were subjected to further studies in order to rescue antibiotic actions. Singular activity of essential oils and activity when combined with an antibiotic was hence elucidated. The results obtained highlighted the occurrence of strong antibacterial potential of essential oils when administrated alone. In the interactive experiment essential oils were found highly effective in reducing the resistance of Methicillin-resistant Staphylococcus aureus to amoxicillin, tetracycline, piperacillin, ofloxacin and oxacillin and resistance of Acinetobacter baumannii to amoxicillin and to ofloxacin in interactive manner. Furthermore, the results proved synergism among essential oils and both antibiotics ofloxacin and novobiocin against the Extended-Spectrum Beta-Lactamase producing E. coli (ESBL). Time kill kinetics was performed with a combination of sub-inhibitory concentrations to confirm the efficiency and killing rate of the combination over time. Further, the hypothetical toxicity of essential oils against human keratinocytes HaCat and murine spleenocytes were examined. The chemical composition of essential oils was assessed by GC/MS analysis and the major constituents found were sabinene, limonene, terpinen-4-ol, and ß-eudesmol.

Current research status of non-antibiotic antibacterial therapies / 临床儿科杂志

With the inappropriate use of antibiotics, the situation of bacterial resistance is more and more severe. The emergence of multidrug-resistant (MDR) bacteria has made it difficult to cure the infections in clinical. For treatment the infections caused by MDR and reducucton of the generation of resistant bacteria, researchers are actively studying on the non-antibiotic substances for antibacterial activity. In this paper, the advances in those with conifrmed effects such as phage therapy, metal/chelation therapy, immunization therapy, photodynamic therapy, and nitric oxide (NO)-based therapies, small molecule inhibitors, antimicrobial peptides and Chinese herb were reviewed.

Surface plasmon resonance-induced photoactivation of gold nanoparticles as bactericidal agents against methicillin-resistant Staphylococcus aureus.

Systemic infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and other bacteria are responsible for millions of deaths worldwide, and much of this mortality is due to the rise of antibiotic-resistant organisms as a result of natural selection. Gold nanoparticles synthesized using the standard wet chemical procedure were photoexcited using an 808 nm 2 W laser diode and further administered to MRSA bacteria. Flow cytometry, transmission electron microscopy, contrast phase microscopy, and fluorescence microscopy combined with immunochemical staining were used to examine the interaction of the photoexcited gold nano-particles with MRSA bacteria. We show here that phonon-phonon interactions following laser photoexcitation of gold nanoparticles exhibit increased MRSA necrotic rates at low concentrations and short incubation times compared with MRSA treated with gold nanoparticles alone. These unique data may represent a step forward in the study of bactericidal effects of various nanomaterials, with applications in biology and medicine.

Antimicrobial activity of green tea extract against isolates of methicillin-resistant Staphylococcus aureus and multi-drug resistant Pseudomonas aeruginosa.

OBJECTIVE: To evaluate antibacterial activity of the Indonesian water soluble green tea extract, Camellia sinensis, against clinical isolates of methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) and multi-drug resistant Pseudomonas aeruginosa (MDR-P. aeruginosa). METHODS: Antimicrobial activity of green tea extract was determined by the disc diffusion method and the minimum inhibitory concentration (MIC) was determined by the twofold serial broth dilutions method. The tested bacteria using in this study were the standard strains and multi-drug resistant clinical isolates of S. aureus and P. aeruginosa, obtained from Laboratory of Clinical Microbiology, Faculty of Medicine, University of Indonesia. RESULTS: The results showed that the inhibition zone diameter of green tea extracts for S. aureus ATCC 25923 and MRSA were (18.970 ± 0.287) mm, and (19.130 ± 0.250) mm respectively. While the inhibition zone diameter for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were (17.550 ± 0.393) mm and (17.670 ± 0.398) mm respectively. The MIC of green tea extracts against S. aureus ATCC 25923 and MRSA were 400 µg/mL and 400 µg/mL, respectively, whereas the MIC for P. aeruginosa ATCC 27853 and MDR-P. aeruginosa were 800 µg/mL, and 800 µg/mL, respectively. CONCLUSIONS: Camellia sinensis leaves extract could be useful in combating emerging drug-resistance caused by MRSA and P. aeruginosa.