Participation of the arcRACME protein in self-activation of the arc operon located in the arginine catabolism mobile element in pandemic clone USA300

ABSTRACT Staphylococcus aureus pandemic clone USA300 has, in addition to its constitutive arginine catabolism (arc) gene cluster, an arginine catabolism mobile element (ACME) carrying another such cluster, which gives this clone advantages in colonisation and infection. Gene arcR, which encodes an oxygen-sensitive transcriptional regulator, is inside ACME and downstream of the constitutive arc gene cluster, and this situation may have an impact on its activation. Different relative expression behaviours are proven here for arcRACME and the arcACME operon compared to the constitutive ones. We also show that the artificially expressed recombinant ArcRACME protein binds to the promoter region of the arcACME operon; this mechanism can be related to a positive feedback model, which may be responsible for increased anaerobic survival of the USA300 clone during infection-related processes.

Characterization of biofilm formation, antimicrobial resistance, and staphylococcal cassette chromosome mec analysis of methicillin resistant Staphylococcus hominis from blood cultures of children

Abstract INTRODUCTION: Methicillin resistant Staphylococcus hominis (MRSHo) has been recognized as an important human pathogen, particularly in immunocompromised patients. METHODS: A total of 19 S. hominis isolates were collected from children at the Children's Medical Centre, Tehran, Iran, from March 2012 to February 2013. MRSHo susceptibility against 13 antimicrobial and 3 antiseptic agents was determined using disk diffusion (DAD) and minimum inhibitory concentration (MIC), respectively. All isolates were subjected to polymerase chain reaction (PCR) assay for 15 distinct resistance genes, staphylococcal cassette chromosome mec (SCCmec), and arginine catabolic mobile elements (ACMEs). Biofilm production of the isolates was determined using a colorimetric microtiter plate assay. RESULTS: Of the 19 isolates, 16 were resistant to oxacillin and harbored mecA. High resistance was also observed against trimethoprim/sulfamethoxazole (81.2%). All MRSHo isolates were susceptible to the three disinfectants tested (Septicidine-PC, Septi turbo, and Sayacept-HP). In total, 15 (78.9%) isolates produced biofilms. Three isolates had SCCmec types (V and VIII), 13 were untypable (UT), and 5 had ACME type II. CONCLUSIONS: The results indicate that MRSHo with high antibiotic resistance and unknown SCCmec might become a serious problem in the future for the treatment of patients such as children.

Diagnostic ability of Physical Examination in aortic Valve stenosis / La capacidad diagnóstica del examen físico en la estenosis valvular aórtica

background: Physical examination is essential to detect aortic stenosis but there is scarce information currently available. Objectives: The goal of this study is to evaluate the diagnostic yield of physical examination, the interobserver agreement of clinical signs, and to establish a score to identify severe aortic stenosis. Methods: One-hundred patients were included in the study. Before echocardiographic evaluation, two cardiologists independently evaluated the clinical signs of the physical examination in aortic stenosis. Sensitivity, specificity, and inter-observer agreement were calculated, and the area under the curve was analyzed to develop a score for predicting severe aortic stenosis. results: The decreased intensity of the first heart sound and the crescendo-decrescendo shape of the murmur had sensitivity >90% and specificity <70%. The specificities of an absent second sound, a murmur that peaks later in systole and the presence of a parvus et tardus pulse were >95%, but the sensitivities were <50%. Inter-observer agreement was good for most criteria, except for murmur shape and intensity. The best area under the curve was achieved by the score composed of heart sounds of decreased or absent intensity, duration of the holosystolic murmur, parvus et tardus carotid pulse and a grade 3-4 systolic murmur. Conclusions: Physical examination findings have low sensitivity but good specificity. Inter-observer agreement of clinical signs of severity was moderately good. Correct identification of patients with severe aortic stenosis can be achieved using a simple score.

Comparison of Danhong and Salvia Ligustrazin to adjust abnormal level of coagulation factor Ⅶ caused by ACS / 国际中医中药杂志

Objective To compare the regulatory functions of Danhong and Salvia Ligustrazin on abnormal coagulation factors Ⅶ caused by ACS.Methods All cases were randomly divided into group A and B and a control group.Each group contains 60 patients.The control group was treated with conventional western therapies.On this basis,group A Was treated with Danhong injection and group B was treatedwith Salvia Ligustrazin injection.Compare the regulatory function of its group on abnormal level of coagulation factor Ⅶ caused by ACS.Results Group B showed better effects in its regulating abnormal level of coagulation factor Ⅶ as compaared to group A(χ~2=3.67,P＜0.05).Both groups did better than the control group in adjusting coagulation factors Ⅶ (P＜0.05).Conclusion Salvia ligustrazine has better effect in regulating coagulation factors Ⅶ than Dan Hong injection,which is better than conventional western medical therapy.