Aeromicrobiology

this will put a light on air microbiology, air microbes, airborne diseases and factors that influence the bioaerosols.

1. Aero-microbiology Kainat Abbas: 2016-KIU-1058 Diya Fatima: 2016-KIU-1072 Syyeda Urooj:2016-KIU-1429 Zakia: 2016-KIU-1067 Nelofar Hanif: 2016-KIU- Sania Zahra: 2016-KIU-1057 Perveen Alam: 2016-KIU-1382

2. Introduction Microbiology  is the scientific study of microorganisms. Microorganisms are those organisms that are too small to see with the naked eye and include things like bacteria, fungi, and viruses. Air microbiology : is the study of living microbes which are suspended in the air . It is also called aero microbiology.

3. Cont…. The study of microorganisms and their spores invisible to naked eye suspended in air. Study of aero-spoliation, aerial transmission and biological materials. It also includes the study of diseases transmitted through respiratory routes. The field of aero-microbiology is important as it involves, Formation of aerosols.

4. Cont…… Microbes are called bio-aerosols. Microbes normally found in atmosphere within 300-10000 feet above from the land. There are significantly less atmospheric microorganisms than there are in oceans and in soil. These microbes have a chance to travel long distances with the help of wind and precipitate and increase the rate of infectious diseases caused by these microbes.

5. Cont….. The important gases that effect the microorganisms are hydrogen sulphide, sulphur dioxide, carbon monoxide, chlorine, hydrogen fluoride, ozone , etc. The microbial forms are bacteria, fungi and actinomycetes , algae, spores of pteridophytes, pollen grains, micro insects and viruses.

6. History During 1930s the term Aero-microbiology was used to denote the air borne spores (e.g. fungi and other microorganisms ) Further in 1951 , the term was elaborated to include dispersion of insect population, fungal spores, bacteria and viruses. In 1964 , the term included the research work of air borne materials of biological significance.

7. Indoor air microbiology It deals with microorganisms present in air in indoor environment. They are the microorganisms which are responsible biodeterioraton of storage materials, equipment , library materials and archives. Microbes can survive for extended period in indoors as they have relatively less exposure to radiations.

8. Indoor air microbiology It involves home and work place environments in which air borne microbes create major public health concerns. Microbes found in different sites: Aeromicrospora of pharmacy. Aeromicroflora of hospitals. Houses Aeromicroflora of storage materials.

9. Indoor air microbes Indoor air contains more disease causing agents that has higher chances of infections than outdoor air especially in large gatherings like schools and theaters. The commonest genera of fungi in indoor air are Penicillium, Aspergillus . The commonest genera of bacteria found in indoor air are Staphylococci, Bacillus and Clostridium.

10. Outdoor air microbiology The study of air in the atmosphere, which is found outside the buildings, is referred to as outside air\outdoor aero microbiology. In outdoor or extramural environment, the expanse of space and the presence of air turbulence are the two controlling factors in the movement of bio aerosols.

11. Outdoor air microbes The number and kind of microorganism may vary from place to place, depending upon the human population densities. Some of microbes include; Algae Protozoa Yeasts Molds , Mold spore are predominant, e.g clasdosporium Bacterial species are, Spore forming, Non spore forming.

12. Cont….. The dominant microflora of outside air is fungi. The two common genera of fungi are  cladosporiul  and  sporobolomyces. Aspergillus, Alternaria, Phytophthora  and   Erysiphe are other fungal aerosals.

13. Cont….. Also contains besidispores, ascopres of yeast, and fragments of  mycelium  and  canidia  of molds. The bacterial genera include: Bacillus   and  clostridium, sarcina, mirococcus, corynebacterium  and   Achromobacter.  

14. Sources of air microbes Some of the sources are listed below; Soil Water Wind and tidal actions Human beings

15. Cont….  Soil:  soil microbes disturbed by the wind blow, liberated into the air and remain suspended there for a long period of time. Man made actions like digging or ploughing the soil may also release soil borne microbes into the air.

16. Cont…….. Water: water microorganisms release in the form of water droplets or aerosols. Splashing of water by wind action or tidal action may also produce droplets or aerosols. Wind and tidal actions: Air currents may bring the microorganisms from plant or animal surfaces into air. For example, spores of Puccini a graminis

17. Cont………. Human beings: The main source of airborne microorganisms is human beings. Pathogenic flora of the upper respiratory tract and the mouth are discharged into the air by activities like coughing, sneezing, talking and laughing.

18. Forms of discharge The microorganisms are discharged out in three different forms which are grouped on the basis of their relative size and moisture content. droplets, droplet nuclei and infectious dust.

19. Droplets Droplets are usually formed by sneezing, coughing or talking. Each consists of saliva and mucus. It has been estimated that the number of bacteria in a single sneeze may be between 10,000 and 100,000 The size of the droplet determines the time period during which they can remain suspended. Most droplets are relatively large, and they tend to settle rapidly in still air. the droplets containing pathogenic microorganisms may be a source of infectious disease.

20. Droplet Nuclei  Small droplets in a warm, dry atmosphere tend to evaporate rapidly and become droplet nuclei. The residues of solid material left after drying up of a droplet is known as droplet nuclei. These are small, 1-4µm, and light. can remain suspended in air for hours or days, traveling long distances. may serve as a continuing source of infection if the bacteria remain viable when dry.

21. Cont…… Viability is determined by a set of complex factors including: the atmospheric conditions like humidity, sunlight and temperature, the size of the particles bearing the organisms, the degree of susceptibility or resistance of the particular microbial species to the new physical environment.

22. Infectious Dust Large aerosol droplets settle out rapidly from air on to various surfaces and get dried. Nasal and throat discharges from a patient can also contaminate surfaces and become dry. Disturbance of this dried material by bed making, handling a handkerchief having dried secretions or sweeping floors in the patient's room can generate dust particles which add microorganisms to the circulating air

23. Cont…….. Airborne diseases are transmitted by two types of droplets, depending upon their size. Droplet infection proper applies to, droplets larger than 100 µm in diameter. The other type may be called airborne infection, and applies to dried residues of droplets.

24. Factors Affecting Microbes Microbes are continually in the state of stress. Oxygen stress and ionic stress. Temperature stress. Moisture stress/humidity. UV-radiation stress

25. Oxygen and ionic stress: Higher level of oxygen and its reactive forms causes inactivation of enzymes, damage to DNA, inactivation of nucleic acids and proteins. Naturally occurring ions causes ionic stress, lightening, water shearing and ion displacement.

26. Temperature Temperature is the major factor in the inactivation of microbes. High temperature promotes inactivation, mainly associated with desiccation and protein denaturation lower temperature promotes longer survival times. At freezing environment some organisms lose viability because of formation of ice crystals on their surfaces.

27. Moisture content The relative as well as the absolute humidity content of the air play a major role in the survival of the air borne microorganisms. gram-negative bacteria in air survive for longer periods at relative low humidity by regulating their metabolic activities. While Gram-positive at high moisture content .

28. Cont…….. at 100% relative humidity, longer exposure decreases the viability in relation to survival. Intracellular ionic imbalance and loss of cellular metabolites occur when the cell is exposed to unfavorable humidity level. Viruses with enveloped nucleocapsids tend to have better survival in aerosols than without.

29. Radiation stress Shorter wavelength and X-ray causes damage to DNA by Single strand breaks, Double strand breaks and Alteration in structure of DNA. It also affects Genome replication, Transcription and Translation .

30. Significance of air microbes When compared with the microorganisms of other environments, air micro flora is very low in number, they play a very significant role. Because the air is in contact with almost all animate and inanimate objects.

31. Cont.. The significance of air flora has been studied since 1799, in which year Lazaro Spallanzani attempted to disprove spontaneous generation. In 1837, Theodore Schwann , in his experiment to support the view of Spallanzani. Where he introduced fresh heated air into a sterilized meat broth and demonstrated that microbial growth couldn't occur.

32. Cont…. These two scientists formed the basis of modern day forced aeration fermentations. Pasteur in 1861 , which first showed that microorganisms could occur as airborne contaminants.

33. Significance in Human Health Air acts as a medium for the transmission of infectious agents. An adult man inhales about 5m³ of air per day. Most of the microorganisms present in air are harmless saprophytes and commensals, less than 1% of the airborne bacteria is pathogens.

34. Cont…. Even though the contamination level is very low, the probability of a person becoming infected will be greatest if he is exposed to a high concentration of airborne pathogens.

35. Staphylococcus aureus The number of S. aureus in air may vary between 0-1/m³ and 50/m The purity of outdoor air, however, is an essential part of man's environment. In the case of indoor air chance for the spread of infectious disease is more especially in gatherings.

36. Significance in Hospitals Hospitals are the war fields for combating against diseases, there are certain occasions in which additional new infectious diseases can be acquired during hospitalization. Air within the hospital may act as a reservoir of pathogenic microorganisms which are transmitted by the patients. Infection acquired during the hospitalization is called nosocomial infections and the pathogens involved are called as nosocomial pathogens.

37. Cont.. The common microorganisms associated with hospital infection are Haemophilus influenza, Streptococcus pneumonia, Streptococcus pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, members of Enterobacteriaceae and respiratory viruses.

38. Microorganisms in Industries Food manufacture : Microorganisms that have been transported through the air and have settled on, or in, the material are involved in various fermentation products. Production of alcoholic beverages, vinegar, sauerkraut, ensilage, dairy products, etc., is often due to microbial activity

39. cont,…. Spoilage of foods and fermentation products In industrial processes, where particular organisms are to be grown, to supply sterile air free from contaminating organisms is a considerable problem.

40. Bioaerosals control in laboratory Bioaerosal containing airborne microbes can be controlled at every point by using different mechanism which includes: Ventilation Filtration Biocidal agents Isolation

41. Cont…. Ventilation:  It is the most common method to check build up of airborne particles. This can be achieved by open windows or use of air conditioning and heating units that pump outside air into the room. This is cost effective and this will at least reduce the amount of microbes inside room.

42. Cont……. Filtration: Unidirectional air flow filtration is also simple and effective for bioaerosol control . HEPA is used for this purpose and it removes virtually all infectious particles. Bag house filtration has also become common in building

43. Cont.. Biocidal agents: These are used for super heating, super dehydration, ozonation and UV irradiation to eradicate the microorganisms. The most commonly used method is ultraviolet germicidal radiation (UVGI).

44. Cont…. Isolation: Is the enclosure of an environment through the use of positive or negative pressurized air gradients and air tight seals . Isolation chamber in TB wards in hospitals provide protection to other present inside the air from these rooms is exhausted in to the atmosphere passing through a HEPA filter and biocidal control chamber.

45. Cont.. This system work on negative pressurized air. Positive –pressure isolation chambers, working on the opposite principle force air out of the room thus protects occupants of the room from outside contamination.

46. What Are Airborne Diseases? The diseases that caused by air microbes or catch by breathing, These are called airborne diseases. .

47. Cont…. Airborne disease can spread when an infected person coughs, sneezes, or talks. certain viruses or bacteria take flight and hang in the air or land on other people or surfaces

48. Symptoms Airborne diseases usually result in one or more of the following symptoms: inflammation of nose, throat and lungs coughing Sneezing runny nose sore throat swollen glands Headache loss of appetite fever fatigue

49. Types of airborne diseases Many diseases are spread through the air, including : Influenza Tuberculosis (TB) Measles Mumps etc.

50. Influenza Most of us have some experience with the flu. It spreads so easily because it’s contagious about a day before you notice the first symptoms. It remains contagious for another five to seven days. If you have a weakened immune system for any reason, you can spread it to others for longer than that. There are many strains of the flu, and they are constantly changing. That makes it difficult for your body to develop immunities.

51. Tuberculosis (TB) TB is an airborne disease. but this bacterial infection doesn’t spread easily. You generally have to be in close contact with an infected person for a long time. You can be infected without becoming ill or infecting others .

52. About 2.5 billion people worldwide are infected with TB. Most aren’t sick. About 9.6 million people worldwide have active TB. People with a weakened immune system have the greatest risk of developing the disease.

53. Measles Measles is a very contagious disease, particularly in crowded conditions. The virus can remain active in the air or on surfaces for up to two hours . You’re able to infect others up to four days before and four days after the measles rash appears. Most people get the measles only once .

54. Measles is a leading cause of death among children worldwide It is estimated that the measles vaccine prevented 20.3 million deaths from 2000 to 2015.

55. generally starts on your face and neck, and then spreads over the course of a few days.

56. Serious complications of measles include: ear infections diarrhea dehydration It severe respiratory infection blindness swelling of the brain, or encephalitis

57. Mumps Mumps is another very contagious viral disease. You can spread it before symptoms appear and for up to five days after. Mumps used to be quite common in the United States, but rates have declined due to vaccination .