BACKGROUNDThe catheter related infection caused by Staphylococcus epidermidis biofilm is increasing and difficult to treat by antimicrobial chemotherapy. The properties of biofilms that give rise to antibiotic resistance are only partially understood. This study aimed to elucidate the penetration of erythromycin through Staphylococcus epidermidis biofilm.

METHODSThe penetration ratio of erythromycin through Staphylococcus epidermidis biofilms of 1457, 1457-msrA, and wild isolate S68 was detected by biofilm penetration model at different time points according to the standard regression curve. The RNA/DNA ratio and the cell density within the biofilms were observed by confocal laser microscope and transmission electromicroscope, respectively.

RESULTSThe penetration ratios of erythromycin through the biofilms of 1457, 1457-msrA, and S68 after cultivation for 36 hours were 0.93, 0.55 and 0.4, respectively. The erythromycin penetration ratio through 1457 biofilm (0.58 after 8 hours) was higher than that through the other two (0.499 and 0.31 after 24 hours). Lower growth rate of the cells in biofilm was shown, with reduction of RNA/DNA proportion observed by confocal laser microscope through acridine orange stain. Compared with the control group observed by transmission electrmicroscope, the cell density of biofilm air face was lower than that of agar face, with more cell debris.

CONCLUSIONSErythromycin could penetrate to the Staphylococcus epidermidis biofilm, but could not kill the cells thoroughly. The lower growth rate of the cells within biofilm could help decreasing the erythromycin susceptibility.

Acridine Orange ; Anti-Bacterial Agents ; pharmacokinetics ; Biofilms ; DNA, Bacterial ; analysis ; Erythromycin ; pharmacokinetics ; pharmacology ; Microscopy, Electron, Transmission ; RNA, Bacterial ; analysis ; Staphylococcus epidermidis ; drug effects ; metabolism

BACKGROUNDThe duration of viral shedding and the transmission of 2009 H1N1 influenza among individuals, especially among the younger population with mild illness, are not well understood now. The aim of this study was to determine the viral shedding of the young adult patients with mild 2009 H1N1 influenza in China.

METHODSFrom September 2009 to January 2010, the clinical data and serial nasopharyngeal swabs of 67 patients with 2009 H1N1 influenza and 37 patients with seasonal influenza aged from 18 years to 35 years were collected. The nasopharyngeal swab samples were detected by real time RT-PCR to determine the viral shedding. All the patients did not receive the antiviral therapy but Chinese medicine for detoxicating.

RESULTSAmong the patients with H1N1 virus infection, 82.1% (55/67) patients presented with fever symptom, while more patients with high fever (≥ 39°C) were found in seasonal influenza patients (P < 0.05). For the H1N1 patients, the median interval between the symptom onset and the undetectable RNA was six days (4 - 10 days). But viral shedding was still found in 31.3% patients after 7 days following illness onset. The median interval between disappearance of fever and an undetectable viral RNA level was three days (2 - 8 days), and 17.9% patients were found to be viral shedding 6 days later after normalization of body temperature. For the seasonal influenza patients, 94.6% patients were detected out viral RNA within 7 days. The median interval of seasonal influenza between the symptom onset and the undetectable RNA was four days (3 - 8 days). The median interval between disappearance of fever and an undetectable viral RNA level was three days (2 - 6 days).

CONCLUSIONIt suggests that 7 days isolation period from the illness onset or 24 hours after the resolution of fever and respiratory symptoms are not long enough to cut off the transmission among Chinese young adults with mild illness.

Adult ; Female ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; pathogenicity ; Influenza, Human ; epidemiology ; virology ; Male ; Real-Time Polymerase Chain Reaction ; Virus Shedding ; genetics ; physiology ; Young Adult

OBJECTIVETo evaluate the diagnostic efficiency of colloidal gold and dot ELISA rapid tests in clinical screening of influenza A virus.

METHODSThe pharyngeal swabs were collected from 297 outpatients suspected of influenza between June and October, 2009 for detection with colloid gold and dot ELISA rapid test, with real-time PCR as the golden methods. The discrepant results of colloid gold and dot ELISA methods were confirmed by sequencing, and the diagnostic efficiency of the two methods was evaluated.

RESULTSAmong the 166 samples with influenza A virus infection as confirmed by real-time PCR and sequencing, the diagnostic sensitivity of dot ELISA and colloid gold methods was 54.82% (91/166) and 4.22% (7/166), respectively. The total concordance rate with PCR was 66.67% (Kappa value of 0.35). Among the 133 samples negative for influenza A virus, the specificity of dot ELISA and colloid gold methods was 81.68% (107/131) and 98.47% (129/131), respectively, with a total concordance rate with PCR of 45.79% (Kappa value 0.02). Of the 99 H1N1 influenza samples confirmed by real-time PCR, the detection rate of dot ELISA was 67.3%, whereas that of colloid gold was 5.1%. Out of the 107 dot ELISA-positive but colloid gold-negative samples, 84 were confirmed to be influenza A virus-positive by real-time PCR and sequencing. One sample negative for dot ELISA but positive for colloid gold test was confirmed to be influenza A virus-negative. The detection rate and diagnostic concordance rate for influenza A virus by dot ELISA were significantly higher than those of colloid gold (P<0.05).

CONCLUSIONDot ELISA is better than colloid gold in influenza A virus detection and shows great prospect in clinical screening.

Enzyme-Linked Immunosorbent Assay ; Gold Colloid ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza, Human ; diagnosis ; virology ; Real-Time Polymerase Chain Reaction ; Sensitivity and Specificity

China ; Female ; Health Services Needs and Demand ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza Vaccines ; therapeutic use ; Influenza, Human ; prevention & control ; Intention ; Male ; Medical Staff ; Pregnancy ; Students ; Vaccination ; statistics & numerical data

This study was aimed to establish the method of quantitative PCR (q-PCR) of fungi in peripheral blood for diagnosis of invasive fungal infections in patients with hematologic malignancies, and to preliminarily assess the diagnostic value of this method. The 18S rDNA-ITS1 area of high consensus sequence of fungi was selected to design primer and probe, the DNA of fungal species was extracted and q-PCR was performed to evaluate the sensitivity and specificity of the primer and probe. The standard product of fungal DNA was prepared by using pGEM-T plasmid and the fungal DNA in blood of patients was quantitatively detected. The results showed that the positive was found in 12 Aspergillus and 14 Candida species according to q-PCR detection, while there was no significant difference of fungal distribution between plasma, mononuclear cells and leukocytes (p<0.05). Receiver-operating characteristic analysis of q-PCR showed that the cut-off value for clinical diagnosis of invasive fungal infection was 8 copies/ml whole blood, its sensitivity, specificity, positive and negative predictive value and kappa were 0.84, 0.9, 0.955, 0.692 and 0.679 respectively. It is concluded that the fungal q-PCR assay may be used as an early diagnostic method for invasive fungal infections in patients with hematologic malignancies.
Aspergillus ; isolation & purification ; Candida ; isolation & purification ; Female ; Hematologic Neoplasms ; complications ; microbiology ; Humans ; Male ; Mycoses ; complications ; diagnosis ; Polymerase Chain Reaction ; methods ; Sensitivity and Specificity

Objective To evaluate the safety and epidemiological effects on the first mass vaccination program, using the China-made A (H1N1) influenza vaccine. Methods Descriptive epidemiology and cohort study design were used to assess the influenza A H1N1 vaccine on its safety and epidemiological effects. Results 95 244 subjects were immunized with A (H1N1) influenza vaccine. 193 adverse events were reported through AEFI Management System, with the Reported rates after immunization was carried out. Of 81 adverse reactions confirmed to be related to immunization,reported through the AEFI Management System. The epidemiological protection rate of A (H1N1)influenza vaccine showed a similar safety profile to seasonal flu vaccine. The vaccine demonstrated a good epidemiological effects against A (H1N1) influenza virus infection.

OBJECTIVETo explore the apoptosis resistance induced by Leptin and its mechanism in breast cancer cells in vitro.

METHODSThe leptin-mediated reduction of docetaxel-induced apoptosis in human breast cancer T47D cells was evaluated by TransAM ELISA, MTT and caspase-9 assay. The leptin-promoted survivin expression was analyzed by Western-blot and RT-PCR. The reversing effect of STAT3 knockdown on leptin-induced survivin upregulation was measured by Western-blot and RT-PCR.

RESULTSLeptin promoted T47D cells proliferation and the inhibitory rate was -63.6%. It reduced docetaxel-induced apoptosis in T47D cells by 31.9%. Leptin at different concentrations promoted survivin protein and mRNA expression in T47D cells. The expression of survivin mRNA was 4.6 fold compared with the T47D cells not treated with leptin(10 nmol/L). The expression of survivin mRNA in T47D cells was 0.55 +/- 0.15 fold after transfected with small interfering RNA (siRNA) of STAT3. The expression of survivin mRNA in STAT3 siRNA group and mock transfected group were 0.56 +/- 0.18 fold and 1.61 +/- 0.22 fold after treated by leptin, respectively. The survivin protein level of T47D mock transfected cells was increased after treated by leptin, but the protein level of T47D transfected with STAT3 siRNA cells were not changed significantly.

CONCLUSIONLeptin/STAT3 signaling is a novel pathway for up-regulation of survivin expression in breast cancer cells.

Apoptosis ; drug effects ; Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Female ; Humans ; Inhibitor of Apoptosis Proteins ; Leptin ; pharmacology ; Microtubule-Associated Proteins ; genetics ; metabolism ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; STAT3 Transcription Factor ; genetics ; metabolism ; Signal Transduction ; Transfection ; Up-Regulation

OBJECTIVEScrub typhus is an infectious disease due to Orientia tsutsugamushi transmitted by infected chigger mites. Scrub typhus has long been recognized to occur in southern areas of China, but has recently been increasingly often reported from the north since the first case was reported in Mengyin County, Shandong Province in 1986. The key objectives of the present study were to investigate the clinical manifestations and epidemic factors of scrub typhus in children from the northern new natural foci.

METHODSThe case records of 56 children with scrub typhus who were admitted to the 5 hospitals of Fei County from September 1993 to January 2004 were reviewed. Orientia tsutsugamushi (Ot) was isolated from the cases. Based on ecological observations on the composition, seasonal fluctuation of animal hosts and chigger mites, Ot was isolated from rodents and chiggers. IgG antibodies to Ot was detected by IFA. Genotypes of the Ot isolates were also identified by nested PCR.

RESULTSAmong 56 children scrub typhus cases, 46 were male, 10 were female; 96% exhibited typical eschars or ulcers, 100% cases had high fever, skin rashes were observed in 55 cases (98%), and regional lymphadenopathy occurred in 48 cases (86%). All cases came from countryside, and all had histories of exposure to the crop field. fifty-one serum samples of suspected patients with scrub typhus were collected, 48 were positive for antibodies to Ot. The serotypes were Gilliam types. The cases only appeared in September to December with the peak at mid and late October. Leptotrombidium (L.) scutellare was the most important vector causing scrub typhus in the foci. Apodemus (A.) agrarius was the main host animals of Ot in the crop field. Totally 26 strains were isolated from patients, rodents, and chigger mites. The serotypes of 24 out of the 26 isolates were Gilliam types, while the genotypes of these isolates were Kawasaki types. The serotypes of the other 2 isolates were identical and both were Karp types.

CONCLUSIONChildren scrub typhus patients were frequently seen in the new natural foci of Shandong province. Exposure history, typical eschars or ulcers, and presence of IgG antibody were the important indexes to diagnose the disease.

Adolescent ; Animals ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mice ; parasitology ; Orientia tsutsugamushi ; isolation & purification ; Scrub Typhus ; epidemiology ; Seasons ; Trombiculidae ; microbiology

OBJECTIVETo analyze the genetic differences of Orientia tsutsugamushi (Ot) Sta56 gene between Shandong isolates and other strains deposited in GenBank.

METHODSPCR and restriction fragment length polymorphism (RFLP) were used to amplify the complete sequence of Ot-Sta56 gene. RFLP profiles of Ot were predicted by a computer program according to their complete sequences of Ot-Sta56 gene. PCR amplicon from XDM2 strain was sequenced and analyzed by Clustal X (1.8) and PHYLIP software.

RESULTSThe complete sequences (about 1.6 kbp) of Ot-Sta56 gene were amplified from B16 strain (isolated from patients), FXS2 strain (isolated from A. agrarius) and XDM2 strain. Four species of restriction endonucleases (Hha I, Hinf I, Hae III, Pst I) were used to digest the PCR amplicons from the 3 isolates. When comparing with the RFLP profiles of prototype Ot, the RFLP profiles of PCR amplicons from the 3 isolates were similar to those of Japan Kawasaki strain, but were quite different from the international reference strains Gilliam, Karp, Kato. Results from DNA sequence analysis showed that the complete sequence of Ot-Sta56 gene homology to Japan Kawasaki strain of XDM2 strain was 97%, and deduced amino acid sequence was 92%.

CONCLUSIONData from the complete sequence of Sta56 gene indicated that the genotypes of Ot isolates in Shandong province were similar, but with distinction from the Kawasaki strain.

Amplified Fragment Length Polymorphism Analysis ; Antigens, Bacterial ; genetics ; Bacterial Proteins ; genetics ; Bacterial Typing Techniques ; classification ; DNA, Bacterial ; genetics ; Genes, Bacterial ; Membrane Proteins ; genetics ; Orientia tsutsugamushi ; genetics ; isolation & purification ; Polymorphism, Restriction Fragment Length ; Sequence Analysis, DNA

OBJECTIVEBy measuring airflow and ventilation distribution of ward building, to explore and verify the hypothesis of airborne transmission and risk factor of severe acute respiratory syndrome (SARS) nosocomial infection.

METHODSTracer gas (perfume of plant oil) was emitted to the bathroom of wards when SARS index patient lived. Six different experimental situations were designed to control the status of exhaust fan in bathrooms, exhaust fan in the top of building and fresh air exchange system. The concentration of perfume was separately measured by 4 groups of lab workers and recorded blindly by the scores of "tenth degree".

RESULTSTracer gas was detected from the wards of 8th to 13th floor.

CONCLUSIONArchitecture and ventilation system of the inpatient building in the hospital contributed to the aerodynamic condition of SARS nosocomial infection through airborne transmission. The distribution of tracer gas in the wards was associated with SARS patients in this building. It was possible that SARS could have been transmitted to for distance by aerosol or other carriers.

Air Microbiology ; China ; Cross Infection ; etiology ; Hospitals ; Humans ; SARS Virus ; isolation & purification ; Severe Acute Respiratory Syndrome ; transmission ; Ventilation