Bacterial Profile and Antibiotic Resistance in Patients with Diabetic Foot Ulcer in Guangzhou, Southern China: Focus on the Differences among Different Wagner’s Grades, IDSA/IWGDF Grades, and Ulcer Types

Objective. To understand the bacterial profile and antibiotic resistance patterns in diabetic foot infection (DFI) in different Wagner’s grades, IDSA/IWGDF grades, and different ulcer types in Guangzhou, in order to provide more detailed suggestion to the clinician about the empirical antibiotic choice. Methods. 207 bacteria were collected from 117 DFIs in Sun Yat-sen Memorial Hospital from Jan.1, 2010, to Dec.31, 2015. The clinical data and microbial information were analyzed. Results. The proportion of Gram-negative bacteria (GNB) was higher than Gram-positive bacteria (GPB) (54.1% versus 45.9%), in which Enterobacteriaceae (73.2%) and Staphylococcus (65.2%) were predominant, respectively. With an increasing of Wagner’s grades and IDSA/IWGDF grades, the proportion of GNB bacterial infection, especially Pseudomonas, was increased. Neuro-ischemic ulcer (N-IFU) was more susceptible to GNB infection. Furthermore, with the aggravation of the wound and infection, the antibiotic resistance rates were obviously increased. GPB isolated in ischemic foot ulcer (IFU) showed more resistance than the N-IFU, while GNB isolates were on the opposite. Conclusions. Different bacterial profiles and antibiotic sensitivity were found in different DFU grades and types. Clinician should try to stay updated in antibiotic resistance pattern of common pathogens in their area. This paper provided them the detailed information in this region

HGF-Induced PKCζ Activation Increases Functional CXCR4 Expression in Human Breast Cancer Cells

The chemokine receptor CXCR4 and its ligand CXCL12 have been shown to mediate the metastasis of many malignant tumors including breast carcinoma. Interaction between hepatocyte growth factor (HGF) and the Met receptor tyrosine kinase mediates development and progression of cancers. HGF is able to induce CXCR4 expression and contributes to tumor cell invasiveness in breast carcinoma. However, the mechanism of the CXCR4 expression modulated by c-Met-HGF axis to enhance the metastatic behavior of breast cancer cells is still unclear. In this study, we found that HGF induced functional CXCR4 receptor expression in breast cancer cells. The effect of HGF was specifically mediated by PKCζ activity. After transfection with PKCζ-siRNA, the phosphorylation of PKCζ and CXCR4 was abrogated in breast cancer cells. Interference with the activation of Rac1, a downstream target of HGF, prevented the HGF-induced increase in PKCζ activity and CXCR4 levels. The HGF-induced, LY294002-sensitive translocation of PKCζ from cytosol to plasma membrane indicated that HGF was capable of activating PKCζ, probably via phosphoinositide (PI) 3-kinases. HGF treatment also increased MT1-MMP secretion. Inhibition of PKCζ, Rac-1 and phosphatidylinositol 3-kinase may attenuate MT1-MMP expression in cells exposed to HGF. Functional manifestation of the effects of HGF revealed an increased ability for migration, chemotaxis and metastasis in MDA-MB-436 cells in vitro and in vivo. Our findings thus provided evidence that the process of HGF-induced functional CXCR4 expression may involve PI 3-kinase and atypical PKCζ. Moreover, HGF may promote the invasiveness and metastasis of breast tumor xenografts in BALB/c-nu mice via the PKCζ-mediated pathway, while suppression of PKCζ by RNA interference may abrogate cancer cell spreading

Molecular epidemiology and virulence characteristics of Staphylococcus aureus nasal colonization in medical laboratory staff: comparison between microbiological and non-microbiological laboratories

Abstract Background Medical laboratory staff are a high-risk population for colonization of Staphylococcus aureus (S. aureus) due to direct and dense contact with the pathogens; however, there is limited information about this colonization. This study sought to determine the prevalence and molecular characteristics of nasal colonization by S. aureus in medical laboratory staff in Guangzhou, southern China, and to compare the differences between microbiological laboratory (MLS) and non-microbiological laboratory (NMLS) staff. Methods S. aureus colonization was assessed by nasal swab cultures from 434 subjects, including 130 MLSs and 304 NMLSs from 33 hospitals in Guangzhou. All S. aureus isolates underwent the antimicrobial susceptibility test, virulence gene detection and molecular typing. Results The overall prevalence of S. aureus carriage was 20.1% (87/434), which was higher in MLSs than in NMLSs (26.2% vs. 17.4%, P < 0.05), while the prevalence of Methicillin-resistant S. aureus (MRSA) was similar. Living with hospital staff was associated with S. aureus carriage. The majority of the isolates harboured various virulence genes, and those in MLSs appeared less resistant to antibiotics and more virulent than their counterparts. A total of 37 different spa types were detected; among these, t338, t437, t189 and t701 were the most frequently encountered types. T338 was the main spa type contributing to nasal colonization Methicillin-sensitive S. aureus (MSSA) (13.0%), and t437-SCCmec IV was predominant in MRSA isolates (40%). Conclusions These findings provide insight into the risk factors, molecular epidemiology and virulence gene profiles of S. aureus nasal carriage among the medical laboratory staff in Guangzhou

Akt pathway activation reduces platelet apoptosis and contributes to the increase of platelet counts in solid tumor patients

Platelets counts increase in various cancer patients, which is associated with poor prognosis. However, the cause of high platelet counts in cancer patients is still not fully understood. Here we demonstrated that compared with healthy controls, there were significant differences in platelet parameters, mean platelet volume (MPV), platelet distribution width (PDW), platelet larger cell ratio (P-LCR), and platelet crit (PCT), reflecting platelet volume in breast cancer patients by clinical retrospective analysis. The mitochondrial transmembrane potential (ΔΨm) depolarization and phosphatidylserine (PS) externalization declined, accompanied by reduced expression of pro-apoptotic factors Bak, Bax and apoptotic executor caspase-3, and elevated of anti-apoptotic factor Bcl-xl in various cancer patients’ platelets. Notably, the phosphorylation level of Akt and its downstream target Bad increased in platelets from cancer patients. MK2206, the inhibitor of Akt, reduced the phosphorylation level of Akt and Bad, and induced apoptosis of platelets. When platelets from healthy controls cocultured with the cultural supernatant of cancer cells, the phosphorylation level of Akt and Bad in the platelets was elevated and the cultural supernatant of cancer cells could rescue the apoptosis of platelet induced by MK2206. Therefore, in our study the apoptosis of platelets in cancer patients was declined, which exerted an influence on the rise of platelet counts in breast cancer patients. The cross-talking between tumor and platelets could affect platelet apoptosis by regulating Akt signaling pathway in platelets

Disinfection Strategies for Carbapenem-Resistant Klebsiella pneumoniae in a Healthcare Facility

Disinfectant resistance is evolving into a serious problem due to the long-term and extensive use of disinfectants, which brings great challenges to hospital infection control. As a notorious multidrug-resistant bacterium, carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the most common and difficult pathogens of nosocomial infection. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests of seven kinds of disinfectants (0.1% benzalkonium bromide, 4% aqueous chlorhexidine, 75% alcohol, entoiodine II, 2% glutaraldehyde, 2000 mg/L chlorine-containing disinfectants, and 3% hydrogen peroxide) were detected by the broth dilution method. Three efflux pump genes (oqxA, oqxB, and qacE&#8710;1-sul1) were detected by PCR. The mean MIC value of aqueous chlorhexidine from the intensive care unit (ICU) (0.0034%) was significantly higher than that from non-ICUs (0.0019%) (p &lt; 0.05). The positive rates of three efflux pump genes oqxA, oqxB and qacE&#8710;1-sul1 were 60.9% (39/64), 17.2% (11/64) and 71.9% (46/64) in the detected CRKP isolates, respectively. This study discovered that CRKP strains demonstrated extensive resistance to clinical disinfectants and suggest that it is necessary to perform corresponding increases in the concentration of aqueous chlorhexidine and chlorine-containing disinfectants on the basis of current standards in the healthcare industry

A case of Cardiobacterium valvarum endocarditis with cerebral hemorrhage after MVR, TVP and vegetation removal operation

Abstract Background Cardiobacterium is a fastidious Gram-negative bacillus, and is a rare human pathogen in clinical settings. Herein, we describe a case of Cardiobacterium valvarum (C. valvarum) endocarditis with a rare complication of cerebral hemorrhage after mitral valve replacement (MVR), tricuspid valve prosthesis (TVP) and vegetation removal operation. Case presentation A 41-year-old woman who had a history of gingivitis developed into infective endocarditis due to the infection of C. valvarum. Then, she was hospitalized to receive MVR, TVP and vegetation removal operation. The indicators of patient tended to be normal until the abrupt cerebral hemorrhage occurred on day 15 after operation. This is the first well-described case of C. valvarum infection in China, and the first report of C. valvarum endocarditis with cerebral hemorrhage after MVR, TVP and vegetation removal operation worldwide. Conclusions We reported the first case of C. valvarum infection in China clinically, with a rare complication of cerebral hemorrhage after MVR, TVP and vegetation removal operation

HGF results in PI3K/Akt pathway phosphorylation and activates CXCR4 phosphorylation via PKCζ.

<p>(A). Detection of phosphorylated Akt or of the respective total Akt protein expression and Rac1-GTP or total Rac1 expression by western blot analysis. MDA-MB-436 cells were added with PBS or were exposed to HGF/SF (for 10 minutes at 50 ng/ml) after preincubation with the PI3-kinase inhibitors wortmannin (at 100 nM, for 60 min) or LY 294002 (at 10 µM, for 60 min) as indicated. The experiment was repeated twice with similar results. A representative study is shown. (B) Membrane CXCR4 expression in MDA-MB-436 cells cultured in the absence or presence of wortmannin (100 nM) or LY 294002 (50 µM, starting 1 hour prior to HGF/SF treatment) with or without HGF/SF treatment (for 16 hour at 50 ng/ml) as indicated. The flow cytometry analysis data are shown in arbitrary units (AU) as the mean ± SD of three independent experiments. # P<0.01 as compared to PBS. (C) MDA-MB-436 cells were exposed to HGF with or without PI 3-kinase inhibitor LY294002 (30 µM) or Akt inhibitor III (50 µM) for various amounts of time, which resulted in the phosphorylation of PKCζ. Western blotting of total protein were performed in triplicate. A representative study is shown. (D). Cellular distribution of PKCζ and CXCR4 before and after 30 minutes of HGF stimulation. HGF, 50 ng/ml, for 10 minutes; LY294002, 30 µM, for 60 min. The experiment was repeated three times with similar results. A representative study is shown.</p

HGF upregulates CXCR4 expression and membrane presentation in human breast cancer cells.

<p>(A). qRT-PCR analysis of the total CXCR4 mRNA extracted from HGF- or SDF-1-treated MDA-MB-436 and MCF-7 cells. Results are presented as the mean ± SD of three independent experiments. # P<0.01 as compared to PBS. (B). Western blot analysis of the total protein expression and phosphorylation levels of Met or CXCR4 in MDA-MB-436 and MCF-7 cells cultured for 24 hours with and without the presence of 50 ng/ml HGF or 20 ng/ml SDF-1. The experiment was repeated twice with similar results. A representative study is shown. (C). Time course of the relative extracted CXCR4 mRNA expression in MDA-MB-436 and MCF-7 cells following stimulation with 50 ng/ml HGF. Results are presented as the mean ± SD of three independent experiments. # P<0.01,* P<0.05 as compared to PBS. (D). Western blot analyses of CXCR4 protein expression in HGF-treated MDA-MB-436 and MCF-7 cells. The experiment was repeated three times with similar results. A representative study is shown. (E). Flow cytometric analysis of MDA-MB-436 cells stained for the expression of CXCR4 using a CXCR4 monoclonal antibody and isotype controls. The experiment was repeated three times with similar results. A representative study is shown. (F). Increased membrane and intracellular CXCR4 labeling in MDA-MB-436 cells incubated for 24 hours in the presence of 50 ng/ml HGF compared with untreated cells (PBS) taken as 1. Flow cytometry analysis data (mean±SD of three independent experiments) are shown. # P<0.01,* P<0.05 as compared to PBS. (G). Decreased internalization rate of anti-CXCR4-PE mAb in MDA-MB-436 cells treated for 24 hours with HGF compared with PBS. Results are presented as the mean ± SD of three independent experiments. * P<0.05 as compared to PBS at each time point.</p

Overexpressed CXCR4 in HGF-stimulated MDA-MB-436 cells is functional.

<p>(A–B). Confluent cells were grown in 0.5% FBS medium for 24 hours and were then wounded with a tip. The cells were washed, and the medium was replaced with or without addition of HGF, PSζ peptides or AMD3100. Representative micrographs of the wounds are shown together with the results of the migration quantification. Results are presented as the mean ± SD of 3 independent experiments. # P<0.01 as compared to PBS. Original magnification, 200×. (C).Dose and time-dependent response of HGF-induced MDA-MB-436 cell migration. (D).Dose-dependent response of HGF-induced MDA-MB-436 cell chemotaxis. (E).PKC and CXCR4 regulate HGF-mediated chemotaxis. MDA-MB-436 cells were incubated for 30 minutes with 10 µM chelerythrine chloride, an inhibitor of all PKC, or for 1 hour with 10 µM of PS-α/β, PS-ε, or PSζ peptide. (F). Boyden chamber assays were performed using the SDF-1 ligand for CXCR4 as a chemotactic attractive agent in the lower chamber. AMD3100, PSζ, PSα/β, PSε and NSC23766 (upper) or PKCζ-siRNA (lower) was added to the cell culture for the blocking assay. Data are shown as the mean ± SD of three experiments. A representative study is shown. (G). qRT-PCR analysis of the MT1-MMP mRNA extracted from MDA-MB-436 cells cultured for 24 hours with the indicated agents. Results are presented as the mean ± SD of three independent experiments. # P<0.01 as compared to PBS. (H). Western blot analysis of the total protein expression levels of MT1-MMP in MDA-MB-436 cells cultured for 24 hours with the indicated agents. The experiment was repeated three with similar results. A representative study is shown.</p

Immunohistochemical staining of HGF, c-Met and CXCR4 in breast cancer specimens.

<p>Original magnification, 400×. (A) Representative micrographs of immunohistochemical results for negative HGF, c-Met or CXCR4 staining in breast benign diseases (an atypical hyperplasia or carcinoma in situ) and for positive HGF, c-Met or CXCR4 staining in an invasive breast carcinoma; (B) Representative micrographs of immunohistochemical results for positive HGF, c-Met and CXCR4 staining cell counts, where the intensity of immunohistochemical staining correlates with the histopathological grading of invasive breast carcinomas.</p