Detection of mecA Genes in Hospital-Acquired MRSA and SOSA Strains Associated with Biofilm Formation.

Methicillin-resistant (MR) Staphylococcus aureus (SA) and others, except for Staphylococcus aureus (SOSA), are common in healthcare-associated infections. SOSA encompass largely coagulase-negative staphylococci, including coagulase-positive staphylococcal species. Biofilm formation is encoded by the icaADBC operon and is involved in virulence. mecA encodes an additional penicillin-binding protein (PBP), PBP2a, that avoids the arrival of ß-lactams at the target, found in the staphylococcal cassette chromosome mec (SCCmec). This work aims to detect mecA, the bap gene, the icaADBC operon, and types of SCCmec associated to biofilm in MRSA and SOSA strains. A total of 46% (37/80) of the strains were S. aureus, 44% (35/80) S. epidermidis, 5% (4/80) S. haemolyticus, 2.5% (2/80) S. hominis, 1.25% (1/80) S. intermedius, and 1.25% (1/80) S. saprophyticus. A total of 85% were MR, of which 95.5% showed mecA and 86.7% ß-lactamase producers; thus, Staphylococcus may have more than one resistance mechanism. Healthcare-associated infection strains codified type I-III genes of SCCmec; types IV and V were associated to community-acquired strains (CA). Type II prevailed in MRSA mecA strains and type II and III in MRSOSA (methicillin-resistant staphylococci other than Staphylococcus aureus). The operon icaADBC was found in 24% of SA and 14% of SOSA; probably the arrangement of the operon, fork formation, and mutations influenced the variation. Methicillin resistance was mainly mediated by the mecA gene; however, there may be other mechanisms that also participate, since biofilm production is related to genes of the icaADBC operon and methicillin resistance was not associated with biofilm production. Therefore, it is necessary to strengthen surveillance to prevent the spread of these outbreaks both in the nosocomial environment and in the community.

Aptamers: A Cutting-Edge Approach for Gram-Negative Bacterial Pathogen Identification.

Early and accurate diagnoses of pathogenic microorganisms is essential to correctly identify diseases, treating infections, and tracking disease outbreaks associated with microbial infections, to develop precautionary measures that allow a fast and effective response in epidemics and pandemics, thus improving public health. Aptamers are a class of synthetic nucleic acid molecules with the potential to be used for medical purposes, since they can be directed towards any target molecule. Currently, the use of aptamers has increased because they are a useful tool in the detection of specific targets. We present a brief review of the use of aptamers to detect and identify bacteria or even some toxins with clinical importance. This work describes the advances in the technology of aptamers, with the purpose of providing knowledge to develop new aptamers for diagnoses and treatment of different diseases caused by infectious microorganisms.

Mesenchymal stem cells attenuate the proinflammatory cytokine pattern in a guinea pig model of chronic cigarette smoke exposure.

AIMS: Cigarette smoke often induces pulmonary and systemic inflammation. In animal models, mesenchymal stem cells (MSC) tend to ameliorate these effects. We aimed to explore the local and systemic expression of cytokines in guinea pigs chronically exposed to cigarette smoke, and their modifications by MSC. MAIN METHODS: Concentrations of IL-1ß, IL-6, IL-8, IL-12, TNF-α, INF-É£, TSG-6, MMP-9, TIMP-1, and/or TIMP-2 in serum and bronchoalveolar lavage (BALF) from animals exposed to tobacco smoke (20 cigarettes/day, 5 days/week for 10 weeks) were determined, and mRNA expression of some of them was measured in lung tissue. Intratracheal instillation of allogeneic bone marrow MSC (5x106 cells in 1 ml) was done at week 2. KEY FINDINGS: After cigarette smoke, IL-6 and IFN-γ increased in serum and BALF, while IL-1ß and IL-12 decreased in serum, and TSG-6 and TIMP-2 increased in BALF. IL-1ß had a paradoxical increase in BALF. MSC had an almost null effect in unexposed animals. The intratracheal administration of MSC in guinea pigs exposed to cigarette smoke was associated with a statistically significant decrease of IL-12 and TSG-6 in serum, as well as a decrease of IL-1ß and IFN-γ and an increase in TIMP-1 in BALF. Concerning mRNA expression in lung tissue, cigarette smoke did not modify the relative amount of the studied transcripts, but even so, MSC decreased the IL-12 mRNA and increased the TIMP-1 mRNA. SIGNIFICANCE: A single intratracheal instillation of MSC reduces the pulmonary and systemic proinflammatory pattern induced by chronic exposure to cigarette smoke in guinea pigs. TRIAL REGISTRATION: Not applicable.

Anti-Inflammatory Activity of Piquerol Isolated from Piqueria trinervia Cav.

BACKGROUND: Inflammation is a complex process as a response to several stimuli, such as infection, a chemical irritant, and the attack of a foreign body. Piquerol was isolated from Piqueria trinervia, and its anti-inflammatory activity was evaluated using in vivo and in vitro models. METHODS: Piquerol is a monoterpene that was identified using NMR, FT-IR spectroscopy, and mass spectrometry analysis. The anti-inflammatory activity was tested in vivo in ear edema induced with TPA in mice. Piquerol was also tested on J774A.1 macrophages stimulated with lipopolysaccharide (LPS), and the levels of NO, NF-κB, TNF-α, IL-1ß, IL-6, and IL-10 were determined using ELISA. RESULTS: The results show that piquerol diminished ear edema (66.19%). At 150.51 µM, it also inhibited the levels of NO (31.7%), TNF-α (49.8%), IL-1ß (69.9%), IL-6 (47.5%), and NF-κB (26.7%), and increased the production of IL-10 (62.3%). Piquerol has a membrane stabilization property in erythrocyte, and at 100 µg/mL, the membrane protection was of 86.17%. CONCLUSIONS: Piquerol has anti-inflammatory activity, and its possible mechanism of action is through the inhibition of pro-inflammatory mediators. This compound could be a candidate in the development of new drugs to treat inflammatory problems.

Anti-inflammatory activity of Jefea gnaphalioides (a. gray), Astereaceae.

BACKGROUND: Inflammation is a symptom associated with many diseases. This symptom is treated with steroidal and non-steroidal anti-inflammatory drugs, which can cause severe side effects when used as long-term treatments. Natural products are an alternative source of new compounds with anti-inflammatory activity. Jefea gnaphalioides (Astereaceae) (A. Gray) is a plant species used to treat inflammatory problems, in Mexico. This study determined the anti-inflammatory activity and the composition of the methanol extract of Jefea gnaphalioides (MEJG). METHODS: The extract was obtained by heating the plant in methanol at boiling point for 4 h, and then the solvent was evaporated under vacuum (MEJG). The derivatization of the extract was performed using Bis-(trimethylsilyl) trifluoroacetamide, and the composition was determined by GC-MS. Total Phenols and flavonoids were determined by Folin-Ciocalteu AlCl3 reaction respectively. The antioxidant activity of MEJG was determined by DPPH method. The acute and chronic anti-inflammatory effects were evaluated on a mouse ear edema induced with 12-O-Tetradecanoylphorbol-13-acetate (TPA). Acute oral toxicity was tested in mice at doses of MEJG of 5000, 2500 and 1250 mg/kg. The levels of NO, TNF-α, IL-1ß and IL-6 were determinate in J774A.1 macrophages stimulated by Lipopolysaccharide. The production of inflammatory interleukins was measured using commercial kits, and nitric oxide was measured by the Griess reaction. RESULTS: The anti-inflammatory activity of MEJG in acute TPA-induced ear edema was 80.7 ± 2.8%. This result was similar to the value obtained with indomethacin (IND) at the same dose (74.3 ± 2.8%). In chronic TPA-induced edema at doses of 200 mg/kg, the inhibition was 45.7%, which was similar to that obtained with IND (47.4%). MEJG have not toxic effects even at a dose of 5000 mg/kg. MEJG at 25, 50, 100 and 200 µg/mL decreased NO, TNF-α, IL-1ß and IL-6 production in macrophages stimulated with LPS. The major compounds in MEJG were α-D-Glucopyranose (6.71%), Palmitic acid (5.59%), D-(+)-Trehalose (11.91%), Quininic acid (4.29%) and Aucubin (1.17%). Total phenolic content was 57.01 mg GAE/g and total flavonoid content was 35.26 mg QE/g MEJG had antioxidant activity. CONCLUSIONS: MEJG has anti-inflammatory activity.