Gram-Positive and Acid-Fast Bacteria - Coursework Example

 Gram-Positive and Acid-Fast Bacteria What is the purpose of general growth media, selective media, and differential media? Give examples of each. Growth media is a gel or rather a liquid that is used to support the growth of the microorganism or small plants. Examples include; nutrient broths. Selective medium is a technique used to grow particular microorganism for instance if an organism is resistant to an individual antibody i.e. ampicillin then that antibiotic is added to the growth medium in order to prevent cells that do not have resistance from growing. Example, Hektoen enteric agar. Differential media is a method that is utilized to distinguish one microorganism from the next in situations where both are growing in the same medium. Example; Eosin methylene blue is differential for the fermentation of lactose. 2. What is a pure culture? How do you obtain a pure culture? A pure culture is a population of multicellular or cells growing in the absence of other species. A pure culture can be obtained from a mixed culture by transferring a sample population into a new growth medium in such a manner as to disperse the individual cells across the medium surface. 3. Name and describe the stages of bacterial growth. How would you keep a culture in the stationary phase? Lag phase- at this stage the bacteria gets to adopt them to the growth condition. They undergo maturation, but they are not capable of dividing. Log phase- the phase if characterized by cell multiplication. Normally, the number of new bacteria per unit time is proportional to the current population. The stationary phase is premised on growth inhibiting factors. Stationary phase- It is the stage where growth rate is proportional to the death rate. Death phase- It is the stage where the bacteria finally die due to adverse living conditions that are brought about by the limiting factors. A culture can be kept in the stationary phase by invoking growth inhibiting factors such as high/low temperatures as well as limiting the amount of nutrients available for the bacteria. 4. Describe the different sterilization techniques and know when to use each type. (For example, when would you use an autoclave, gas, etc.?) Steam autoclave- it combines moisture and high temperatures to kill microorganisms. The technique utilizes temperature ranging from 121-148 degrees Celsius at a pressure of 15 P.S.I. Typically, the sterilization period is dependent on the load and temperature but can vary from ten minutes to one hour. It is used for surgical equipment. Chemical sterilization- The method utilized chemical agents that have the ability to kill microorganism for instance ethylene oxide gas. It is a low-temperature sterilization process that requires a direct contact with the equipment for them to be sterilized. It is used for items that are sensitive to moisture and heat. Radiation sterilization- It involves the items being exposed to radiations at temperatures of thirty to forty degrees Celsius with a dose of 2.5 megarads. The technique is standard for sterilizing medical equipment prior to shipment. 5. For the bacterial control methods described, know their mode of action. (For example, how does alcohol monitor the growth of bacteria?) Heat- it kills bacteria by denaturing enzymes Low temperatures- make the bacteria be inactive since they do not reproduce at low temperatures High pressure- destroys bacteria by denaturing proteins in vegetative cells Osmotic pressure- the bacteria are killed through plasmolysis 6. How would you prevent the spread of a pathogen? Pathogens are spread by touching unclean or rather infected surfaces. In order to prevent the spread of pathogen people ought to maintain a proper personal hygiene, observing frequent hand wash after contact with people or surfaces as well as regular disinfection and cleaning. The Prokaryotes 1. What is the Gram Stain used for? What are the differences between a Gram positive and Gram negative cell? The gram stain is a technique used for differentiating between bacterial species that is gram-positive and gram-negative bacteria. The differentiation is achieved by use of the physical and chemical properties of the walls of the bacteria. Gram-positive bacteria have a thick membrane surrounded by peptidoglycan and, as a result, hey are stained purple by crystal violet. On the other hand, Gram-negative bacteria have a relatively thinner membrane with a layer of peptidoglycan. They do not retain the purple stain and, as a result, they are counterstained pink by safranin 2. Describe the characteristics of an Acid Fast bacterium. What can bacteria be identified using the Acid-Fast Staining technique (also known as the Ziehl-Neelson technique)? What diseases do these bacteria cause? Acid fast bacterium normally has a high concentration of mycolic acid and a layer of lipid in their walls a factor that makes them have the rare acid fastness characteristic. Given the high level of mycolic acid in their walls, they are difficult to stain. However, once the stain gets into their wall, it cannot be readily decolorized. Some of the bacteria that can be tested using the Acid Fast technique include; Mycobacterium and nocardia. The bacteria cause tuberculosis and leprosy respectively. 3. What bacterial structures/features increase the pathogenicity of the bacteria? Virulence factors, flagella, fimbriae and surface components. Bacteria Name/Disease Signs and Symptoms Common hosts/reservoirs Portals of entry and exit Mode Transmission How is the disease diagnosed? How is the disease prevented? Mycobacterium tuberculosis Cough that lasts three or more weeks Unintentional weight loss Chest pains Pain while breathing Chills Fatigue fever humans Nose/ respiratory system It is spread through the air from one individual to the next If a person has a positive TB bold or skin test Avoiding crowned areas, ensuring homes and office places are well ventilated. Bacillus anthracis Dry cough, Malaise Fever Chest discomfort Domesticated herbivores i.e. cattle Cut in the skin, gastrointestinal and respiratory Close contact with animals or their products especially wool and animal skin It is diagnosed through the isolation of bacillus anthracis from skin lesson, blood or respiratory secretions Vaccination and controlling of anthrax in animals from spreading to human beings Pseudomonas aeruginosa Fever Chills Increased sputum production Malaise Shortness of breath Increased heart rate Water soils, agricultural plants, animals and human beings Cutaneous It enters the human body of immune compromised people through the skin Diagnosed through the isolation of Pseudomonas aeruginosa from blood, wounds, body fluids, sputum and feaces cultures Consistent overall hygiene Staphylococcus aureus Collection of pus such as furuncle and boils Fever Irritating and painful skin Humans and some domestic animals Cutaneous Spread from person to the next through contaminated hands Isolation of Staphylococcus aureus from the sample taken from the affected area Maintaining proper hand hygiene Escherichia coli Fever, fatigue Vomiting Gas Abdominal cramping Loss of appetite Human beings and animals gastrointestinal Spread when a person gets into contact with feaces and through hand contact from one person to the next Through the isolation of Escherichia coli from a stool sample of the patient Maintaining proper hygiene and good food preparation techniques Mycoplasma Pneumoniae Fever Headache Fatigue Sore throat Worsening cough that lasts for months Humans Respiratory, cutaneous Spread through the contact of respiratory fluids Chest (x-ray), listening to breathing to detect any abnormalities, computerized tomography and serology assay Getting enough sleep, eating and balanced diet and avoiding people with MP symptoms Bordetella pertussis Running nose Low grade fever Apnea Occasional cough Vomiting Fatigue humans respiratory Spread through the contact of respiratory fluids Isolation of Bordetella pertussis from a culture Vaccination, anyone who is diagnosed with Bordetella pertussis should stay away from work or school Salmonella enteric serovar Enteritidis Abdominal cramps Diarrhea fever Humans and animals like rodents, reptiles Gastrointestinal Spread through contaminated food and Isolation of Salmonella enteric serovar Enteritidis from the culture Maintaining food hygiene and hand hygiene Streptococcus Pneumoniae Chest pain High fever Cough Shortness of breath Headache Nausea Fatigue Rapid breathing humans Respiratory, cutaneous Transmitted through contact with people who are ill or rather carry the bacteria in their throat Isolation of Streptococcus Pneumoniae from the sample taken from the patient Avoiding contact with infected persons as well as vaccination corynebacterium diphtheriae Chills Fever Swollen lymph nodes Difficulty in breathing Loud barking breath Bluish skin Sore throat humans respiratory The bacteria is transmitted through respiratory droplets from cough and droplets Isolation of corynebacterium diphtheria from a throat culture as well as checking of swelling in the lymph nodes Prevented through vaccination Legionella pneumophila Cough Fever Chest pain Diarrhea Breathlessness water Respiratory and cutaneous It is spread through natural water sources It is diagnosed using a series of blood tests Proper disinfection and maintenance of water sources Clostridium perfringens Dehydration Diarrhea abdominal cramps gas humans gastrointestinal Its spread through contaminate food It is diagnosed by testing a type of bacteria toxin in feaces Proper hygiene and handling of food Vibrio cholerae Loss of skin elasticity Rapid heart rate Low blood pressure Muscle cramps Thirst Human beings and aquatic sources gastrointestinal The bacteria is transmitted through contaminate food and water Diagnosed by the isolation of Vibrio cholera from a stool culture Vaccination, boiling water before use and maintaining general hygiene Shigellosis Vomiting nausea Watery diarrhea abdominal cramping Presence of blood or mucus in stool Water and human beings Gastrointestinal The bacteria is transmitted through contaminate food and water Isolation of Shigellosis or their toxins in a stool sample of the patient Practicing proper personal hygiene and avoiding contact with infected people Treponema pallidum. Sores in the genitals and around the mouth Skin rash Moist warts in the groin Swollen lymph glands Fever Weight loss Human beings Genital tract It is transmitted from one person to the next through sexual activity with an infected person including anal and oral sex. Diagnosis involved a test isolating Treponema pallidum in a blood culture Having protected sex Chlamydia trachomatis Burning pain while urinating Vaginal discharge Fever Testicular pain Nausea Lower abdominal pain humans Genital tract Typically transmitted through sexual activity Diagnosed by screening tests for instance urine test and swab for the end of the penis or cervix Having protected sex and vaccination Neisseria gonhorrheae Spotting after sex Breeding within periods Greenish-yellow discharge from the vagina Swollen glands in the throat Burning pain when urinating Pelvic pain Humans Genital tract Spread through sexual contact with an infected person Isolation of Neisseria gonorrhea from a fluid sample from the urethra in men and cervix in women Having protected sex Clostridium tetanus Chills Head ache Irritability Sore throat Low fever Legs and arm stiffness Soil and human beings Cutaneous The bacteria is spread by cuts with dirty objects for instance needs, nails, surgical objects etc. Diagnosis is based on the presentation of symptoms caused by the bacteria Immunization by use of tetanus toxoid Neisseria meningitidis Altered mental status Nausea Photophobia Vomiting Headache Stiff neck Fever humans Respiratory tract Gastrointestinal Cutaneous The bacteria is spread from one person to the next through throat and respiratory secretions of an infected person Isolation of Neisseria meningitidis from blood or cerebrospinal fluid Prevention is through vaccination Rickettsia rickettsii Headache Nausea Vomiting Conjuctival injection Muscle pain Fever Abdominal pain animals especially ticks Cutaneous Spread through bite by an infected tick Diagnosis is based on the presentation of symptoms caused by the bacteria Avoid areas where one can encounter the carriers Rickettsia prowazekii Head ache Abdominal pain Chills Muscle pain Vomiting Nausea Delirium Low blood pressure Animals such as ticks, flea, rats, lice Cutaneous Spread through bites of an infected carrier Isolation of Rickettsia prowazekii from a blood sample Avoid areas where one can encounter the carriers and use of insecticide Microbes in the Environment . Describe the stages of the disease. Deviation- it is the stage when the body senses imbalance caused by external and internal stressors. The initial reaction of the body is to revert to balance through detoxification. In case, detoxification does not work the disease moves to the next stage Abnormality- at the stage the body still attempt to regain balance, if it is unsuccessful, a catabolic effect occurs, and the tissues and cells begin to disintegrate. Morphology- Since malfunction has already taken place, the tissues, cells and organs have already been damaged. Dysfunction of the mitochondria causes immune breakdown thus making the inner cellular area susceptible to toxins. Symptoms- At this stage the normal functioning of the body is suppressed by the symptoms. Various conditions develop as a result of the symptoms, and the viability of the organisms is highly tested. Death- the changes that have taken place in the cells, tissues, organs and the system due to the effects of the symptoms causes a cessation of the normal body functions. The point where the body can no longer handle adaptation it dies. 2. What is a carrier? Describe the different types of carriers. A carrier is a person that harbors a particular organism causing disease without presenting any symptoms but he/she can transmit the infection to another person. Active carrier- an individual who has pathogens of a particular disease and he/she is manifesting the symptoms of that disease Convalescent carrier- This is an individual who has recovered from the symptoms of disease but still has the pathogens Inoculator Carrier- A carrier that has the pathogens but does not manifest any symptoms. 3. What is a fomite? Any substance or object that is capable of carrying infected organisms for instance parasites or germs 4. Describe the ways that microorganisms can be transmitted. The microorganism can be transmitted through air, contact with animals, through contaminated food or water. 5. What is a reservoir? What are the major types of reservoirs? A reservoir is a site in which pathogens survive prior to entering the host. There are three common types of reservoirs namely; animal reservoir, human carriers and non-living reservoir. 6. What is a vector? A vector is an organism that does not cause a disease, but aids in the spread of the pathogens causing the disease from one host to another. 7. Know the portals of entry and portals of exit. Portals of entry are the routes that pathogens use to enter their host while the portals of exit are the routes used by pathogens to live their host. 8. What makes a potential host susceptible to a pathogen? A possible host is susceptible to a pathogen if it is infected or has defects in its immune mechanisms. Antimicrobial Therapy 1. What is selective toxicity? Why is it important? What is the therapeutic index? Selective toxicity is a characteristic of antibiotics that implies they have a high effect on the microbes but less or not effect at all on human beings. On the other hand, therapeutic index is the ratio of the toxicity dose of the patient to the therapeutic dose of the eliminating infection. 2. What is the difference between bacteriostatic and bactericidal? What is the difference between broad-spectrum and narrow-spectrum antimicrobials? Bactericidal antibiotics generally kill the bacteria directly while the bacteriostatic antibiotics inhibit the growth of bacteria. On the other hand, narrow-spectrum antibiotics are only effective against a limited range of bacteria while broad-range antibiotics are effective over a broad variety of bacteria. 3. What is a super-infection? How is it caused? A superinfection is a situation whereby a subsequent infection is imposed on an earlier infection by a different microbial agent that is typically resistant to the therapy utilized against the first infection. 4. What are the primary modes of action of the antimicrobials discussed? Give example antibiotics for each mode of action. Inhibiting cell wall synthesis- example vancomycin Inhibiting cell membrane function- example polymixin B Inhibiting protein synthesis- example macrolides Inhibiting nucleic acid synthesis-example rifampin Inhibiting of other metabolic proteins- example sulfonamides 5. What is competitive inhibition? Competitive inhibition is a situation where enzyme inhibitors allow fake substrates to compete with real one for the active areas of the enzyme 6. What is noncompetitive inhibition? (Hint: the nucleoside analogs are an example) Non-competitive inhibition occurs when the inhibitor limits the active sites of the enzyme by binding to the enzyme whether it has bound to the substrate or not. 7. What are methods that bacteria use to resist antibiotics? How does antibiotic resistance occur? Adaptation and evolution are some of the methods that bacteria use to resist antibiotics. Antibiotic resistance occurs when the antibiotic used are not effective on the bacteria since it has adapted and developed enhanced resistance to the antibiotic. Immunity and the Immune System 1. Define active immunity, passive immunity, artificial immunity, natural immunity, innate immunity, and specific immunity. Active immunity is acquired when an individual is exposed to live pathogens and, as a result, develops resistance as a consequence of the primary immune response. Passive immunity is acquired through immunization as involves the introduction of antibodies that are frequently not being produced by the receptor’s cells. Innate immunity is natural resistance that is inborn Natural immunity is acquired through contact with a disease causing agent in deliberately while artificial immunity is developed after a deliberate exposure such as immunization 2. Describe humoral immunity. It is a microbially mediated immunity usually in the extracellular fluids for instance antibodies and antimicrobial peptides 3. Describe cell-mediated immunity. Cell-mediated immunity does not invoke antibodies in the immune process but instead it encompasses the activation of antigen-specific cytotoxic T-lymphocytes, phagocytes and releases different cytokines in response to antigens. 4. List and describe the various types of vaccines. Give examples of each. Live/attenuated vaccines – measles Inactivated vaccines- polio Toxoid vaccines- diphtheria Conjugated vaccines- hepatitis B 5. How do vaccines prevent diseases? Typically, vaccines contain an antigen that is inactivated before it is introduced to the body. The vaccine in conjunction with the antigens stimulates the body’s immune system B-cells to develop antibodies. Once the B-cells have been activated they are capable of staying in the organism’s body for a lifetime and allow the immune system to remember the gems that stimulated its creation thus fight its whenever they come into contact. Viruses 1. How do viruses replicate? How does their replication help viruses spread within an individual? Viruses undergo self-replication whereby they divide into daughter cells. The replication increases them in umber thus allowing the daughter cells to spread to the rest of the body. 2. How are RNA and DNA viruses different? RNA viruses are single strand, have a high rate of mutation as well as their replication takes place in the cytoplasm. On the other hand, DNA viruses are double strand, they have a relatively lower rate of replication and at the same time their replication takes place in the nucleus. 3. What is a prion? How does a prion cause a disease? A prion is a protein in nature that is capable of structurally transforming itself into different forms in which one of the structures is transmissible to another prion. The replication of the prion handles causing diseases just like virus replication. Mould, Yeast, and Fungi 1. What are the characteristics of yeast? They are unicellular They have a wide dispersal of natural habitats They reproduce through budding They have the ability to ferment sugars 2. How does yeast replicate? Yeasts reproduce through budding 3. What are common diseases caused by yeast? (This would be described under Candidiasis on the CDC website.) Candidiasis as well as vaginal yeast and mouth thrush 4. What are the characteristics of a mold-type of fungi? Reproduce utilizing spores Uses specialized hyphae called condia to source food from the surface 5. How do fungi replicate? How does their replication help fungi spread within an individual? Fungi replicate asexually through budding. Since it is asexual, they are bale to increase in number they're enhance their area of reach within their host 6. How are the fungal diseases transmitted? (This would be found under the Risk and Prevention section for each disease on the CDC website.) Fungal diseases are primarily transmitted through spores by the aid of water and the wind that are the primary methods of dispersal in the natural habitats. 7. What are the common hosts or reservoirs for the fungal diseases? (This would be found under the Risk and Prevention section for each disease on the CDC website.) Environmental reservoir such as soil and trees 8. How are the fungal diseases prevented? They can be avoided through proper adherence to hygiene 9. What are the signs and symptoms of the fungal diseases? Commonly they have flu-like presentation that include; fever, cough; headache and chills though the symptoms tend to change depending on specific diseases Protozoa and Parasite 1. Identify characteristics of common protozoa or parasites. They are unicellular Ability to move independently Lack of the capability to undertake photosynthesis Reproduce both sexually and asexually They are heterotrophic organisms 2. Determine the cause of a given protozoa or parasite infection in humans. Malaria is caused by the Plasmodium parasite 3. How do the replication mechanisms of protozoa or parasites promote the spread of infection within an individual? Given the fact that these organisms reproduce both sexually and asexually, it increases their chances of replicating thus increasing their population once they get into a host. 4. What are the common portals of entry and exit for the protozoa and parasite diseases? Cutaneous and gastrointestinal tract 5. What are the common hosts or reservoirs for the protozoa and parasite diseases? Water, soil and some animals 6. What are the signs and symptoms of the protozoa and parasite diseases? Most of the protozoa and parasite disease present flu-like signs that are followed by symptoms such as fever, cough; headache and chills. However, the symptoms tend to change with specific diseases. 7. How are the protozoa and parasite diseases transmitted? Protozoa and parasite diseases are typically spread through the contact of infected people or vectors. 8. How are the protozoa and parasite diseases prevented? They can be prevented by disinfecting water bodies since they form the primary reservoir for the parasites and protozoa as well as maintaining general body hygiene to avoid contracting them. References Anderson, R. P. (2006). Outbreak: Cases in real-world microbiology. Washington, DC: ASM Press. Betsy, T., & Keogh, J. (2005). Microbiology Demystified: A self-teaching guide (1st ed.). New York: McGraw Hill Read More