重症监护病房细菌L型主要菌株耐药性变化及护理

目的监测重症监护病房细菌L型主要菌株耐药性变化情况，以指导临床抗生素应用和采取护理措施。方法对2001年1月-2005年12月于重症监护病房检出的金黄色葡萄球菌L型和铜绿假单胞菌L型逐个进行药物敏感试验，统计其耐药性变化情况。结果金黄色葡萄球菌L型和铜绿假单胞菌L型对各种抗菌药物的耐药性呈上升趋势。金黄色葡萄球菌L型对万古霉素仍敏感，铜绿假单胞菌L型对阿米卡星、第三代头孢菌素较敏感。结论应合理使用抗生素、减少抗生素使用频率，并及时用药敏试验，对细菌L型的耐药性进行监测，以指导临床用药和采取相应的护理措施。     

Improper positioning of the elevator lever of duodenoscopes may lead to sequestered bacteria that survive disinfection by automated endoscope reprocessors

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Proteins from latex of Calotropis procera prevent septic shock due to lethal infection by Salmonella enterica serovar Typhimurium

Aim of the study

The latex of Calotropis procera has been used in traditional medicine to treat different inflammatory diseases. The anti-inflammatory activity of latex proteins (LP) has been well documented using different inflammatory models. In this work the anti-inflammatory protein fraction was evaluated in a true inflammatory process by inducing a lethal experimental infection in the murine model caused by Salmonella enterica Subsp. enterica serovar Typhimurium.

Materials and methods

Experimental Swiss mice were given 0.2 ml of LP (30 or 60 mg/kg) by the intraperitoneal route 24 h before or after lethal challenge (0.2 ml) containing 10⁶ CFU/ml of Salmonella Typhimurium using the same route of administration.

Results

All the control animals succumbed to infection within 6 days. When given before bacterial inoculums LP prevented the death of mice, which remained in observation until day 28. Even, LP-treated animals exhibited only discrete signs of infection which disappeared latter. LP fraction was also protective when given orally or by subcutaneous route. Histopathological examination revealed that necrosis and inflammatory infiltrates were similar in both the experimental and control groups on days 1 and 5 after infection. LP activity did not clear Salmonella Typhimurium, which was still present in the spleen at approximately 10⁴ cells/g of organ 28 days after challenge. However, no bacteria were detected in the liver at this stage. LP did not inhibit bacterial growth in culture medium at all. In the early stages of infection bacteria population was similar in organs and in the peritoneal fluid but drastically reduced in blood. Titration of TNF-α in serum revealed no differences between experimental and control groups on days 1 and 5 days after infection while IL-12 was only discretely diminished in serum of experimental animals on day 5. Moreover, cultured macrophages treated with LP and stimulated by LPS released significantly less IL-1β.

Conclusions

LP-treated mice did not succumb to septic shock when submitted to a lethal infection. LP did not exhibit in vitro bactericidal activity. It is thought that protection of LP-treated mice against Salmonella Typhimurium possibly involves down-regulation of pro-inflammatory cytokines (other than TNF-α). LP inhibited IL-1β release in cultured macrophages and discretely reduced IL-12 in serum of animals given LP. Results reported here support the folk use of latex to treat skin infections by topic application.     

Distinct sources and targets of IL-10 during dendritic cell-driven Th1 and Th2 responses in vivo

Dendritic cells (DC) can both initiate an immune response and dictate its character. Cytokines are critically involved in this process and, although interleukin (IL)-10 is known as a potent immunosuppressant, the impact of its release from DC remains unclear. Here, we transfer pathogen-conditioned murine DC in vivo and show that, while DC-derived IL-10 can act to limit Th1 development, it is not required for Th2 induction. In both Th2 and Th1 settings, however, IL-10 from cells other than the initiating DC dominates the regulation of the emerging effector cell populations. Surprisingly, the critical source of IL-10 in this process is neither T nor B cells. These data illustrate the distinct actions of IL-10 during differently polarised, pathogen-focussed, DC-driven immune responses in vivo.     

Lupus: The microbiome angle

Microbiota consists of more than 10¹⁴ microorganisms that inhabit different areas of the body including the gastrointestinal tract, mainly the mouth and gut. It includes viruses, fungi, protozoa, archaea and bacteria. The microbiota interacts closely with host leading to a dynamic relationship that results in the biological effects observed. Its diverse genetic material (microbiome) interacts closely with the host immune system and cells, and therefore is closely associated with inflammation, immune tolerance, adaptive immunity and autoimmune diseases. Bacterial microbiota, which is the mostly studied lives in harmony with the host and maintains a symbiotic relationship. Therefore it plays an important role in immunological, metabolic, and neurological aspects and thereby the well-being of the host. Alteration of the homeostatic environment or the dynamic balance of microorganisms can result in dysbiosis or disease. However, does dysbiosis cause disease, aggravate disease or is the result of the disease remains to be defined, it could be a bit of all three factors. More recently, a number of studies demonstrate that these microorganisms could contribute to disease. Alteration of the tightly balanced composition of bacterial microbiota (dysbiosis) leads to exacerbation, rapid progression and worsening of disease states. It is important to identify the ‘healthy’ microbes that maintain a healthy environment, the ‘sensitive’ microbes that go awry with disease, the ‘bad’ microbes that cause disease and the ‘therapeutic’ microbes that can help rectify the changes. Increased relative abundance of certain bacterial species has been linked to triggering autoimmune diseases. Despite the burgeoning literature in the field, the molecular mechanisms by which the microbiota impacts the body in health and disease remain largely unknown. In this review, we will discuss recent advancements in our understanding of the gut bacterial microbiota associated with inflammatory and immunological processes and the role they play in the autoimmune disease, systemic lupus erythematosus.     

Contribution of the FilmArray® Gastrointestinal Panel in the laboratory diagnosis of gastroenteritis in a cohort of children: a two-year prospective study

This study represents a 2-year picture of the epidemiology of enteric pathogens in children suffering from gastroenteritis using the FilmArray® Gastrointestinal Panel (FA-GP), a multiplex molecular assay that allows to simultaneously detect a large panel of pathogens independently of the etiological suspicion and to evaluate its potential contribution to the diagnosis compared to the conventional methods.A total of 1716 stool samples, collected from children with clinical suspicion of bacterial and/or viral gastroenteritis attending the University Hospital of Parma, was submitted to the FA-GP and, when an adequate aliquot was available, to electron microscopy (n = 1163) for virus detection and to an enterovirus-targeting real-time PCR (n = 1703). Specimens with positive results for Salmonella, Yersinia enterocolitica, Vibrio, diarrheagenic Escherichia coli/Shigella, Campylobacter, Plesiomonas shigelloides and/or parasites by the FA-GP were also submitted to conventional diagnostic methods.The FA-GP gave positive results in 958 (55.8%) cases, 64.8% from inpatients: 647 (67.5%) contained a single agent and 311 (32.5%) multiple agents, for a total of 1374 pathogens. Enteropathogenic E. coli, rotavirus, norovirus, toxigenic Clostridioides difficile, and sapovirus were the most commonly detected pathogens. A total of 812 additional agents (344 of which as single pathogen) was detected by the FA-GP and not included in the clinical suspicion. The overall recovery rate of the conventional methods from stools that resulted positive by the FA-GP was 38.6% for bacteria, 50% and 84.2% for Giardia intestinalis and Cryptosporidium, respectively, and ranged from 3.7% to 64.6% for viruses, if excluding all electron microscopy-negative astroviruses. Enterovirus, an agent not targeted by the FA-GP, was revealed in 9.6% (164/1703) of the examined samples, and in 52 cases it was the only agent detected.The results of this study allowed to extend the range of detectable pathogens independently of the clinical suspicion, to detect co-infections in almost one third of children positive for at least one agent and to show that conventional methods would have missed more than half of the enteric agents detected by the FA-GP.     

Cloning and characterization of two different ficolins from the giant freshwater prawn Macrobrachium rosenbergii

Ficolins, a kind of lectin containing collagen-like and fibrinogen-related domains (FReDs, also known as FBG or FREP), are involved in the first line of host defense against pathogens. In this study, two ficolins, namely, MrFico1 and MrFico2, from the giant freshwater prawn Macrobrachium rosenbergii were identified. In contrast to other ficolins, these two ficolins have no collagen-like domain, but such ficolins contain a coiled region and a FReD domain. Phylogenetic analysis showed that MrFico1 and MrFico2, together with two ficolin-like proteins from Pacifastacus leniusculus, belonged to one group. Quantitative RT-PCR (qRT-PCR) showed that both MrFico1 and MrFico2 were expressed in hepatopancreas, stomach and intestine, with the highest expression in stomach for MrFico1, compared to the highest expression in hepatopancreas for MrFico2. qRT-PCR analysis also showed that MrFico1 was obviously upregulated upon Vibrio anguillarium challenge, while MrFico2 was upregulated after challenged by V. anguillarium or white spot syndrome virus. Bacterium-binding experiment showed that MrFico1 and MrFico2 could bind to different microbes, and sugar-binding assay revealed that these two ficolins could also bind to lipopolysaccharide and peptidoglycan, the glycoconjugates of bacteria surface. Moreover, these two ficolins could agglutinate bacteria in a calcium-dependent manner, and the results of bacteria clearance experiment showed that both ficolins could facilitate the clearance of injected bacteria in the prawn. Our results suggested that MrFico1 and MrFico2 may function as pattern-recognition receptors in the immune system of M. rosenbergii.     

Bacterial imaging with photostable upconversion fluorescent nanoparticles

Autofluorescence, photodamage and photobleaching are often encountered when using downconverting fluorophores and fluorescent proteins for bacteria labeling. These caveats represent a serious limitation when trying to map bacteria dissemination for prolonged periods. Upconversion nanoparticles (UCNs), which are able to convert low energy near-infrared (NIR) excitation light into higher energy visible or NIR light, can address these limitations. These particles' unique optical properties translate into attractive advantages of minimal autofluorescence, reduced photodamage, deeper tissue penetration and prolonged photostability. Here, we report a UCN-based bacteria labeling strategy using Escherichia coli as prototypic bacteria. A comparative analysis highlighted the superior photostability of UCN-labeled bacteria over green fluorescent protein-expressing bacteria. Infection study of UCN-labeled bacteria in dendritic cells indicated co-localization of the UCN signal with bacterial position for up to 6 h post-infection. Furthermore, long-term monitoring of the same infected cells demonstrated the potential to utilize photostable UCN-based imaging for bacterial trafficking purposes.     

Association of <Emphasis Type="Italic">Escherichia</Emphasis><Emphasis Type="Italic">coli</Emphasis> O157:H7 with necrotizing enterocolitis in a full-term infant

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of the neonate. NEC is predominantly seen in premature infants; however, in rare instances it can affect full-term infants as well. Although the pathogenesis of NEC remains elusive, it is well established that bacterial colonization is required for development of this disease. In this report, we present a case of a full-term infant, who developed a very aggressive form of NEC and was found to have Escherichia coli (E. coli) O157:H7 both in stool and blood cultures. Unfortunately, despite aggressive surgical and intensive care management, this infant suffered pan-intestinal necrosis and expired. We were not able to establish the route of transmission. To our knowledge, this is the first report of the association of E. coli O157:H7 with NEC.     

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目的探讨儿童幽门螺杆菌(H.pylori)感染及抗H.pylori治疗对儿童肠道菌群状态的影响。方法将浙江大学医学院附属儿童医院2004年410月门诊收治的68例慢性胃炎、十二指肠球炎患儿分为H.pylori阳性组36例、H.pylori阴性组32例二组。称取68例患儿新鲜粪便1.0g,分别进行需氧和厌氧培养,分离肠道菌群中最有代表性的三种需氧菌(肠杆菌、肠球菌、酵母菌)和四种厌氧菌(双歧杆菌、乳杆菌、类杆菌、产气荚膜梭菌),菌落记数,同时计算B/E比值来代表定植抗力。对36例H.pylori阳性组中的26例患儿进行“三联”抗H.pylori治疗1周后留取新鲜粪便进行肠道菌群分析,5例患儿在停药1个月后再次进行肠道菌群分析。结果H.pylori阳性组和H.pylori阴性组上述三种需氧菌和四种厌氧菌的菌落检出率比较,差异无统计学意义(P>0.05)。抗H.pylori治疗1周后双歧杆菌、乳杆菌、类杆菌菌落数量较治疗前明显降低(P<0.05),B/E值明显下降(P<0.01),酵母菌的检出率明显增加(P<0.05),产气荚膜梭菌检出率下降(P<0.05)。5例患儿在停药1个月后,乳酸杆菌数量仍继续下降,肠杆菌数量继续增加,双歧杆菌、类杆菌数量有所恢复,但仍低于治疗前。结论儿童H.pylori感染后对肠道菌群影响不大;三联疗法抗H.pylori治疗对儿童肠道菌群产生明显的影响,因此在治疗H.pylori感染时须考虑到大量抗生素治疗后可能对患儿的副作用及潜在的危险。