Honey and microbial infections: a review supporting the use of honey for microbial control

Honey has been used as a medicine throughout the ages and has recently been reintroduced to modern medical practice. Much of the research to date has addressed honey's antibacterial properties and its effects on wound healing. Laboratory studies and clinical trials have shown that honey is an effective broad-spectrum antibacterial agent. Honey antimicrobial action explains the external and internal uses of honey. Honey has been used to treat adult and neonatal postoperative infection, burns, necrotizing fasciitis, infected and nonhealing wounds and ulcers, boils, pilonidal sinus, venous ulcers, and diabetic foot ulcers. These effects are ascribed to honey's antibacterial action, which is due to acidity, hydrogen peroxide content, osmotic effect, nutritional and antioxidants content, stimulation of immunity, and to unidentified compounds. When ingested, honey also promotes healing and shows antibacterial action by decreasing prostaglandin levels, elevating nitric oxide levels, and exerting prebiotic effects. These factors play a major role in controlling inflammation and promoting microbial control and healing processes. This article reviews data supporting the effectiveness of natural honey in eradicating human pathogens and discusses the mechanism of actions.     

The index of microbial air contamination

The standard index of microbial air contamination (IMA) for the measurement of microbial air contamination in environments at risk is described. The method quantifies the microbial flow directly related to the contamination of surfaces coming from microbes that reach critical points by falling on to them. The index of microbial air contamination is based on the count of the microbial fallout on to Petri dishes left open to the air according to the 1/1/1 scheme (for 1h, 1m from the floor, at least 1m away from walls or any obstacle). Classes of contamination and maximum acceptable levels have been established. The index of microbial air contamination has been tested in many different places: in hospitals, in food industries, in art galleries, aboard the MIR space station and also in the open air. It has proved to be a reliable and useful tool for monitoring the microbial surface contamination settling from the air in any environment.     

Active microbial decontamination of tilapia fish

Fish grown in contaminated ponds can be exposed to a variety of human pathogenic microorganisms which may accumulate in its tissues. This study was conducted in order to examine the efficiency of changing the water, in the holding tanks, to reduce the level of microorganisms in various fish tissues. Fish contamination was accomplished by seeding 10⁹, 10¹¹ 10¹⁰cfu or pfu ml^‐1 of E.coli, MS2 coliphage and poliovirus 1, respectively, into 1001 of water. These microorganisms were tested in the skin, muscle, liver, spleen and the digestive tract (DT). A single inoculation of the test microorganisms was followed by 3–24 water changes (tank volumes) and compared with self‐purification (control) experiments without changing the water. The highest levels of microorganisms were found in the DT, 6 h after inoculation for E.coli and 12 h after inoculation for MS2 and poliovirus 1. Lower levels of the microorganisms were found in the spleen, liver and on the skin and none were detected in the muscle. In the decontamination experiments, no microorganisms were detected in the DT 5–6 days after inoculation, as compared to 11–21 days in the control experiments. The results of this study indicate that faster decontamination of fish is achieved by repeated changing of the water in the holding tanks and this may lower the risk of disease transmission by fish handling or consumption.     

昆虫抗菌肽研究进展

昆虫是世界上最大的生物种群,大部分人类疾病是以昆虫为媒介而传播的,传播的病原体有病毒、细菌、原虫等,对人类危害极大.随着对昆虫研究的进一步深入,人们发现昆虫体内存在高效的无细胞免疫系统,是一类具有高度适应性和防卫机能的动物.     

Exploring microbial microevolution with microarrays.

Gene arrays are typically employed to monitor gene expression and regulation, but they are finding additional applications in studying patterns of evolution in bacterial genomes. In particular, this approach has been applied to answer questions about the heterogeneity in full gene repertoires among bacterial strains and species without relying on more costly and time-consuming methodologies. In this review, we evaluate some of the evolutionary patterns and processes affecting bacterial genomes as detected with microarrays, and also delineate the limitations and conclusions stemming from such studies.     

Sanitary-hygienic assessment of microbial biofertilizer]

Biological treatment of sewage from pig-breeding complexes allowed to produce microbial biomass and primary sediments. The mixture of these components (1:1) after rendering harmless and drying out become the high effective biofertilizer. The results of chronic experiment on sanitary status of soil (microbial and helminthological indexes) under this biofertilizer usage are discussed, and the harmlessness of it is demonstrated.     

微生物产生消毒剂抗性研究进展

细菌与人类的关系始终处于共生平衡的破坏与恢复之间,随着医学的发展,抗菌药物及化学消毒剂是治愈疾病、消灭细菌的利器,然而也导致细菌产生新的防御机制和侵袭性。感染的预防和控制一直是医院乃至整个医学发展的棘手问题,目前人类对抗菌药物滥用现象已有所重视,各个国家和地区均采取相应的监控措施促使抗菌药物合理的应用。然而细菌的耐药现象不再局限于对抗菌药物,对消毒剂的抗性也不断增加。不同的是,抗菌药物通过具体途径和作用靶点杀灭/抑制病原微生物,而消毒剂则以非特异多靶点机制起作用,使得对其抗性的研究更为复杂^［1］。当细菌产生消毒剂抗性后,呈现出细菌选择性,即那些适应性和抵抗力更强的细菌得以存活,导致更难控制和治疗的感染^［2］。     

Biofilms: microbial life on surfaces

Microorganisms attach to surfaces and develop biofilms. Biofilm-associated cells can be differentiated from their suspended counterparts by generation of an extracellular polymeric substance (EPS) matrix, reduced growth rates, and the up- and down- regulation of specific genes. Attachment is a complex process regulated by diverse characteristics of the growth medium, substratum, and cell surface. An established biofilm structure comprises microbial cells and EPS, has a defined architecture, and provides an optimal environment for the exchange of genetic material between cells. Cells may also communicate via quorum sensing, which may in turn affect biofilm processes such as detachment. Biofilms have great importance for public health because of their role in certain infectious diseases and importance in a variety of device-related infections. A greater understanding of biofilm processes should lead to novel, effective control strategies for biofilm control and a resulting improvement in patient management.     

Adaptive value of sex in microbial pathogens

Explaining the adaptive value of sex is one of the great outstanding problems in biology. The challenge comes from the difficulty in identifying the benefits provided by sex, which must outweigh the substantial costs of sex. Here, we consider the adaptive value of sex in viruses, bacteria and fungi, and particularly the information available on the adaptive role of sex in pathogenic microorganisms. Our general theme is that the varied aspects of sex in pathogens illustrate the varied issues surrounding the evolution of sex generally. These include, the benefits of sex (in the short- and long-term), as well as the costs of sex (both to the host and to the pathogen). For the benefits of sex (that is, its adaptive value), we consider three hypotheses: (i) sex provides for effective and efficient recombinational repair of DNA damages, (ii) sex provides DNA for food, and (iii) sex produces variation and reduces genetic associations among alleles under selection. Although the evolution of sex in microbial pathogens illustrates these general issues, our paper is not a general review of theories for the evolution of sex in all organisms. Rather, we focus on the adaptive value of sex in microbial pathogens and conclude that in terms of short-term benefits, the DNA repair hypothesis has the most support and is the most generally applicable hypothesis in this group. In particular, recombinational repair of DNA damages may substantially benefit pathogens when challenged by the oxidative defenses of the host. However, in the long-term, sex may help get rid of mutations, increase the rate of adaptation of the population, and, in pathogens, may infrequently create new infective strains. An additional general issue about sex illustrated by pathogens is that some of the most interesting consequences of sex are not necessarily the reasons for which sex evolved. For example, antibiotic resistance may be transferred by bacterial sex, but this transfer is probably not the reason sex evolved in bacteria.     

Quantitative microbial monitoring in a dental office

The aim of this study was to evaluate the environmental pollution before and after dental procedures (during one year) in a dental office in which a system of air filtration was effective and suitable procedures of microbial controls were routinely applied for instruments and small surfaces. The air contamination was evaluated during one year by the 'plate' method (Air Microbial Index, AMI) in each room of the dental office following a bimonthly monitoring program. Nutrient agar plates were exposed, in monitored areas for 1 h for each control time and incubated at 37 degrees C for 2 days. The number of viable cells was expressed as colony forming units per plate per hour (CFU/plate/h). During the observation year, the quantitative analysis of the microbiological levels in the operative areas was always within acceptable values. In fact, a range from 4-18 CFU/plate/h was found as the mean of AMI in each controlled room. In particular, the aerosol pollution following dental procedures did not significantly modify AMI values compared with AMI values recorded before dental procedures. Data presented here demonstrate that the combined use of effective infection control procedures and a system of air filtration can be efficacious in reducing airborne environmental contamination in a dental office and emphasise the use of an inexpensive method such as AMI to verify the environmental bacterial pollution.     

Effects of triclosan on soil microbial respiration

The antimicrobial substance triclosan has widespread use in personal care products and can enter the terrestrial environment if sewage sludge is applied to soil. The inhibitory effects of triclosan on basal and substrate-induced respiration (SIR) of three different soils were investigated. Soils were dosed and later redosed with four nominal triclosan concentrations, and respiration rates were measured over time. In each soil, a significant depression in basal respiration was noted after initial dosing, followed by a recovery. The initial extent of respiration inhibition was positively related to the triclosan dose, i.e., respiration was most inhibited at highest triclosan concentration. Differences in respiration inhibition between soils at equivalent dose were inversely correlated with organic matter and clay content, suggesting that the bioavailability of triclosan might have been reduced by sorption to organic carbon or by physical protection in micropores. Substrate-induced respiration was also reduced by the addition of triclosan and subsequently recovered. After redosing with triclosan, basal respiration was enhanced in all soils, suggesting that it was acting as a substrate. However, redosing resulted in SIR inhibition in all treatments above 10 mg triclosan kg(-1) in all three soils, although all soils appeared to be more resistant to perturbation than following initial dosing. The present study suggests that triclosan inhibits soil respiration but that a subsequent acclimation of the microbial community occurs.