Bacterial spores development

Response to a biocide depends upon the cellular stage of development. Sporulation, a process in which a bacterial spore develops from a vegetative cell, involves seven stages (I—VII Chapter 3) of these, stages IV-VII (cortex and coat development) are the most important in relation to the development of biocide resistance. Resistance to biocidal agents develops during sporulation and may be an early, intermediate or late/very late event. For example, resistance to chlorhexidine occurs at an intermediate stage, at about the same time as heat... 

When considering how the evolution of life could have come about, the seeding of terrestrial life by extraterrestrial bacterial spores traveling through space (panspermia) deserves mention. Much is said about the possibility of some form of life on other planets, including Mars or more distant celestial bodies. Is it possible for some remnants of bacterial life, enclosed in a protective coat of rock dust, to have traveled enormous distances, staying dormant at the extremely low temperature of space and even surviving deadly radiation The spore may be neither alive nor completely dead, and even after billions of years it could have an infinitesimal chance to reach a planet where liquid water could restart its life. Is this science fiction or a real possibility We don t know. Around the turn of the twentieth century Svante Arrhenius (Nobel Prize in chemistry 1903) developed this theory in more detail. There was much recent excitement about claimed fossil bacterial remains in a Martian meteorite recovered from Antarctica (not since... 

A sterilization process may thus be developed without a full microbiological background to the product, instead being based on the ability to deal with a worst case condition. This is indeed the situation for official sterilization methods which must be capable of general application, and modem pharmacopoeial recommendations are derived firm a careful analysis of experimental data on bacterial spore survival following treatments with heat, ionizing radiation or gas. 

For heat treatment, a D-value only refers to the resistance of a microorganism at a particular temperature. In order to assess the influence of temperature changes on thermal resistance a relationship between temperature and log D-value can be developed leading to the expression of a z-value, which represents the increase in temperature needed to reduce the D-value of an organism by 90% (i.e. 1 log cycle reduction Fig. 20.2B). For bacterial spores used as biological indicators for moist heat (B. stearothermophilus)... 

The effectiveness of a disinfectant also depends upon the age of the microorganism. For example, young bacteria can easily be killed, while old bacteria are resistant. As the bacterium ages, a polysaccharide sheath is developed around the cell wall this contributes to the resistance against disinfectants. For example, when using 2.0 mg/L of applied chlorine dosage, for bacterial cultures of about 10 days old, it takes 30 min of contact time to produce the same reduction as for young cultures of about one day old dosed with one minute of contact time. In the extreme case are the bacterial spores they are, indeed, very resistant and many of the chemical disinfectants normally nsed have little or no effect on them. 

Inhaled pathogens behave similarly to solid particulates in a physical sense. Many pathogens (such as soil fungus spores, viruses, bacteria, and bacterial spores) are in the appropriate size range to be able to penetrate to the alveoli, where they encounter warm, moist, nutrient-rich conditions that can promote pathogen development and absorption into the blood stream. 

New reagentless, E-Field based samphng approaches have been developed and integrated with conventional ATR-FTIR flow cells for the detection and identification of bacterial spores in water. Our results show how E-field concentration of spores onto the surface of an ATR crystal surface can enable low concentrations of spores to be measured. The collection cells are designed for easy interface with virtually any IR spectrometer or detection system, and can prove usefirl in a variety of military, homeland defense, and technological apphcations. 

The urea ferments are widely distributed in nature, being found in the air, in the dunghill, in sewage and in dty mud. To cultivate these ferments, a solution of peptone with addition of 0.2-0.3 per cent of urea is used. According to Machida, the addition of magnesium sulphate to the culture medium greatly favors the development of bacteria. The fermentation of urea takes place especially well at a temperature of 30 at 5° almost no anunonia is formed at 60-70 , the cells of Uro-coccus succumb, though bacterial spores can be kept alive up to 80 . 

Although a knowledge of the microbiological origin and history of the product is useful, sterilisation processes can be developed on a worst case scenario. Bacterial spores are more resistant than vegetative cells and can be used as... 

NASA s Jet Propulsion Laboratory (JPL) developed a bacterial spore-detection system for Mars-bound spacecraft that can also recognize anthrax and other harmful, spore-forming bacteria on Earth and alert people of the impending danger. 

In order to prevent the development of tolerances or resistances of the pathogens to the disinfectants, a regular change of the disinfectants is highly desirable. The aetive ingredients of surface disinfeetants are aldehydes (II, 2.), quaternary ammonium compounds (II, 18.1.), and phenolics (II, 7.). Alcohols can only be used for the disinfection of small areas due to the risk of explosions. The bacterial spores ought to be destroyed by peroxygen compounds, such as the peracetic add (El, 21.1.). 

A number of laboratories have developed TOF mass spectrometers for the analysis of aerosol particles and aerosolized bacterial spores. In these instruments, aerosol particles are brought from the atmosphere directly into the vacuum region by means of an aerodynamic lens, skimmers, and differentially pumped regions. They are then ionized directly in flight by a pulsed laser beam. While most of these studies have involved laser desorption, the addition of matrix coatings to aerosol particles in flight has been reported in a MALDI bioaerosol mass spectrometer. 

The anthrax bioterrorist attacks that followed the events of September 11th 2001 resulted in a renewed interest BadUus anthracis, the causative agent of this disease. Research has focused on the development of better vaccines than the one currently available. It has been estimated that the aerosolized release of 100 kg of anthrax spores upwind of Washington DC would cause mortalities of 130,000-3,000,000 [63]. Nonetheless, wild-type Bacillus anthracis is susceptible to conventional antibiotics, including penicillin, oxyfloxacin and ciprofloxacin. The problem lies not with the bacterial infection itself, but with three proteins released by the bacteria - protective antigen (PA, 83 kDa), lethal factor (LF, 90 kDa) and edema factor (EF, 89 kDa) -known as anthrax toxins [63]. 

---