The details of all steps involved in the quantification of
biofilm formation in microtiter plates are described. The
presented protocol incorporates information on assessment of
biofilm production by staphylococci, gained both by direct
experience as well as by analysis of methods for assaying
biofilm production. The obtained results should simplify
quantification of biofilm formation in microtiter plates, and
make it more reliable and comparable among different
laboratories.

Quantification of biofilm in microtiter plates: overview oftesting conditions and practical recommendations for assessmentof biofilm production by staphylococci.

Traditional herbal medicine: Therapeutic potential in rheumatoid arthritis.

Plant-microbial interaction: The mechanism and the application of microbial elicitor induced secondary metabolites biosynthesis in medicinal plants.

Andrographolide ameliorates oxidative stress, inflammation and histological outcome in complete Freund's adjuvant-induced arthritis.

Melittin is one of the most studied antimicrobial peptides, and several in vitro experiments have demonstrated its antibacterial efficacy. However, there is evidence showing melittin has non-promising effects such as cytotoxicity and hemolysis. Therefore, concerns about unwanted collateral toxicity of melittin lie ahead in the path toward its clinical development. With these considerations, the present study aimed to fill the gap between in vitro and in vivo studies. In the first step, in vitro toxicity profile of melittin was assessed using cytotoxicity and hemolysis tests. Next, a maximum intraperitoneal (i.p.) sub-lethal dose was determined using BALB/c mice. Besides toxicity, antimicrobial efficacy of melittin against extensively drug-resistant (XDR) Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus (MRSA), and KPC-producing Klebsiella pneumonia (KPC-KP) pathogens were tested using both in vitro and in vivo methods. Melittin showed extensive hemolysis (HD50 = 0.44 µg/mL), and cytotoxicity (IC50 = 6.45 µg/mL) activities with i.p. LD50 value of 4.98 mg/kg in BALB/c mice. In vitro antimicrobial evaluation showed melittin MIC range from 8 to 32 µg/mL for the studied pathogens. Treatment of infected mice with repeated sub-lethal doses of melittin (2.4 mg/kg) displayed no beneficial effect on their survival and peritoneal bacterial loads. These results indicate that melittin at its safe dose could not exhibit antimicrobial activity, which hinders its application in clinical practice.

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In vitro and in vivo toxicity and antibacterial efficacy of melittin against clinical extensively drug-resistant bacteria.

Evaluation of the effect of andrographolide and methotrexate combined therapy in complete Freund's adjuvant induced arthritis with reduced hepatotoxicity.

Therapeutic effects of gentiopicroside on adjuvant-induced arthritis by inhibiting inflammation and oxidative stress in rats

Objectives Limited therapeutic options exist for treating severe infections caused by multidrug-resistant (MDR) and extensively drug-resistant Gram-negative bacteria (GNB). In this study, the activity of colistin (COL) as monotherapy and in combination with other antibiotics against Acinetobacter baumannii in vitro was investigated. In addition, the efficacy of intravenous colistimethate sodium (CMS) was evaluated in a murine model of urinary tract infection (UTI) induced by MDR Escherichia coli. Methods Minimum inhibitory concentration (MIC), Monte Carlo simulation, fractional inhibitory concentration index (FICI), time–kill study and erythrocyte lysis assay were applied to evaluate the effect and cytotoxicity of COL, meropenem, imipenem, doripenem (DOR) and sulbactam alone and in combination. For the in vivo experiment, determination of the bacterial burden and histopathological examination were performed to evaluate the efficacy of CMS against UTI. Results Of 106 A. baumannii isolates, 104 (98.1%) were susceptible to COL. In the chequerboard assay, COL + DOR showed the highest rate of synergism (60%). No antagonism or cytotoxicity was observed. All COL-based combinations were able to inhibit or slow bacterial re-growth in a time–kill assay. In an in vivo activity study, intravenous CMS reduced not only the bacterial load but also inflammation and maintained structural integrity of infected bladders and kidneys. Conclusion The effectiveness of COL alone in vitro and in vivo suggested that intravenous CMS will be an effective and available therapeutic strategy for UTI due to MDR-GNB. In-depth in vitro tests demonstrated that COL + DOR could be an attractive option, especially when the COL MIC is ≥1 μg/mL.

In vitro and in vivo assessment of the antibacterial activity of colistin alone and in combination with other antibiotics against Acinetobacter baumannii and Escherichia coli.

Xiaotian Li

Papers

Andrographolide ameliorates oxidative stress, inflammation and histological outcome in complete Freund's adjuvant-induced arthritis.

Evaluation of the effect of andrographolide and methotrexate combined therapy in complete Freund's adjuvant induced arthritis with reduced hepatotoxicity.

Therapeutic effects of gentiopicroside on adjuvant-induced arthritis by inhibiting inflammation and oxidative stress in rats

In vitro and in vivo assessment of the antibacterial activity of colistin alone and in combination with other antibiotics against Acinetobacter baumannii and Escherichia coli.