miR-16在金黄色葡萄球菌脓毒症中的表达及意义探讨

目的探讨miR-16表达水平与金黄色葡萄球菌脓毒症严重程度的关联性,进一步探讨其潜在的临床意义。方法收集金黄色葡萄球菌脓毒症血液标本共计32例,脓毒性休克、严重脓毒症和一般脓毒症各8例,不同年龄段的健康对照24例;另外,收集革兰氏阴性菌脓毒症血液标本8例。用Trizol液裂解全血后提取microRNA,采用荧光定量PCR测定miR-16在不同组的表达水平(2-△△Ct法),用SPSS 13.0软件分析各组之间的统计学差异。采用SPSS 13.0软件将miR-16定量值与相应CRP和PCT值进行相关性分析。结果 miR-16表达水平与金黄色葡萄球菌脓毒症严重程度呈明显的负关联,各实验组与对照组相比均有统计学差异(P0.001),实验组之间也有统计学差异(P0.01)。miR-16表达水平与CRP和PCT值呈负相关性,相关系数分别为-0.561和-0.769。结论 miR-16表达与金黄色葡萄球菌脓毒症有明显的负关联性,提示其可能作为该菌脓毒症严重程度的标记物。     

Tracing Staphylococcus aureus in small and medium-sized food-processing factories on the basis of molecular sub-species typing

Contamination by Staphylococcus aureus of the production environment of three small or medium-sized food-processing factories in Slovakia was investigated on the basis of sub-species molecular identification by multiple locus variable number of tandem repeats analysis (MLVA). On the basis of MLVA profiling, bacterial isolates were assigned to 31 groups. Data from repeated samplings over a period of 3 years facilitated to draw spatial and temporal maps of the contamination routes for individual factories, as well as identification of potential persistent strains. Information obtained by MLVA typing allowed to identify sources and routes of contamination and, subsequently, will allow to optimize the technical and sanitation measures to ensure hygiene.     

Genetic diversity and antimicrobial resistance of Staphylococcus aureus from recurrent tonsillitis in children

The aim of this study was to analyze the prevalence of Staphylococcus aureus in the tonsils of children subjected tonsillectomy due to recurrent tonsilitis and to determine the spa types of the pathogens, carriage of virulence genes and antimicrobial resistance profiles. The study included 73 tonsillectomized children. Bacteria, including S. aureus were isolated from tonsillar surface prior to tonsillectomy, recovered from tonsillar core at the time of the surgery, and from posterior pharynx 2–4 weeks after the procedure. Staphylococcus aureus isolates were compared by spa typing, tested for antimicrobial susceptibility and for the presence of superantigenic toxin genes (sea-seu, eta, etb, tst, lukS/lukF-PV) by multiplex polymerase chain reaction. Seventy-three patients (mean 7.1 ± 4.1 years, 61.6% male) were assessed. The most commonly isolated bacteria were S. aureus. The largest proportion of staphylococcal isolates originated from tonsillar core (63%), followed by tonsillar surface (45.1%) and posterior pharynx in tonsillectomized children (18.2%, p = 0.007). Five (6.3%) isolates were identified as MRSA (mecA-positive). Up to 67.5% of the isolates synthesized penicillinases (blaZ-positive isolates), and 8.8% displayed MLS_B resistance. The superantigenic toxin genes were detected in more than half of examined isolates (56.3%). spa types t091, t084, and t002, and clonal complexes (CCs) CC7, CC45, and CC30 turned out to be most common. Staphylococcus aureus associated with RT in children showed pathogenicity potential and considerable genetic diversity, and no clones were found to be specific for this condition although further studies are needed.     

儿童皮肤软组织金黄色葡萄球菌感染的耐药分析

目的对儿童皮肤软组织感染中金黄色葡萄球菌的耐药性进行分析,有效预防与控制多药耐药医院感染的发生,指导临床抗菌药物的合理使用。方法随机选取2012年1月-2014年1月医院收治的200例皮肤组织感染患儿,通过鼻拭子或感染部位标本进行培养,对分离出的金黄色葡萄球菌进行药敏试验,并对病原菌耐药性进行统计分析。结果 200例皮肤组织感染患儿中共分离出金黄色葡萄球菌137株,阳性率为68.5%;137例金黄色葡萄球菌致皮肤组织感染患儿中,儿科病房占72.3%、儿童内科占19.7%、新生儿科占8.0%;感染部位分布以脐部、手指甲沟、颈部、脚趾甲沟、上肢为主,分别占20.44%、14.60%、13.87%、12.41%、10.95%;金黄色葡萄球菌对青霉素、磺胺甲噁唑/甲氧苄啶、氯霉素、红霉素的耐药率较高,均>50.00%,对氨苄西林/舒巴坦、苯唑西林、头孢唑林、万古霉素较敏感,耐药率<14.00%。结论针对皮肤软组织感染患儿临床应结合金黄色葡萄球菌耐药分析结果选取耐药率较低的抗菌药物进行治疗,同时严格开展日常护理,有效改善患儿临床感染症状。     

Modulation of ENaC,CFTR, and iNOS expression in bronchial epithelial cells after stimulation with Staphylococcus epidermidis (94B080) and Staphylococcus aureus (90B083)

Bacteria affect the respiratory epithelium, which is covered by airway surface liquid (ASL) and mucus. Ion concentrations in the ASL are determined by the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na⁺ channel (ENaC). Neonatal sepsis is a major risk factor for subsequent pulmonary disease in preterm newborns. Predominating are coagulase‐negative staphylococci (e.g., Staphylococccus epidermidis and Staphylococccus aureus). The aim of this study was to investigate modulation of CFTR, ENaC, mucins, proinflammatory cytokines, and inducible nitric oxide synthase (iNOS) in respiratory epithelial cells after S. epidermidis 94B080 and S. aureus 90B083 exposure. Bronchial epithelial cells were incubated with S. epidermidis 94B080 and S. aureus 90B083 (neonatal blood isolates) for 1–36 h. Expression of CFTR, ENaC, iNOS, and mucins was analyzed by real‐time PCR and Western blotting. Release of cytokines was analyzed by ELISA, and production of NO by the Griess assay. Expression of CFTR significantly decreased after 36 h incubation with S. epidermidis and more prominently with S. aureus, whereas S. epidermidis caused a significant increase in the expression of β‐ and γ‐ENaC. Expression of iNOS increased, but NO was not detected. Both staphylococci caused a decrease in the intracellular Ca²⁺ concentration. S. aureus induced increased secretion of IL‐6, IL‐8, and transforming nuclear factor (TNF)‐α in a time‐dependent manner as compared with S. epidermidis. In conclusion, expression of ENaC, CFTR, and iNOS is modulated by exposure to S. aureus 90B083 and S. epidermidis 94B080. S. aureus is more potent in causing release of IL‐6, IL‐8, and TNF‐α by bronchial epithelial cells as compared with S. epidermidis. The mRNA expression for the mucus proteins MUC2, MUC5AC, and MUC5B could not be measured, neither in the presence nor in the absence of bacteria.     

Facing Antibiotic Resistance: Staphylococcus aureus Phages as a Medical Tool

Staphylococcus aureus is a common and often virulent pathogen in humans. This bacterium is widespread, being present on the skin and in the nose of healthy people. Staphylococcus aureus can cause infections with severe outcomes ranging from pustules to sepsis and death. The introduction of antibiotics led to a general belief that the problem of bacterial infections would be solved. Nonetheless, pathogens including staphylococci have evolved mechanisms of drug resistance. Among current attempts to address this problem, phage therapy offers a promising alternative to combat staphylococcal infections. Here, we present an overview of current knowledge on staphylococcal infections and bacteriophages able to kill Staphylococcus, including experimental studies and available data on their clinical use.