Human Diseases Caused by Bacteria - Term Paper Example

Chapter 39; Human Diseases Caused By Bacteria

Classifications of Bacterial Diseases

Bacterial infections are among the leading causes of human deaths in the world. Most bacterial infections are curable if detected early but that is mostly not the case. Bacterial diseases are usually classified according to their mode of transmission. These classifications include; those transmitted through the air, those transmitted through arthropods, direct contact bacterial diseases, those transmitted through contaminated food and water, zoonotic disease and opportunistic diseases caused by bacteria.

Air-borne bacterial disease

These infections are those that are transferred from one person to another through the air by inhalation of the infectious particle or by self-inoculation. These diseases mostly affect parts of the respiratory tract including the throat, bronchus and lungs, some in acute cases affect the skin. Air-borne infections may include mycobacterium infections found in soil, water and dust. Some well-known examples of air-bone bacterial diseases are Chlamydial Pneumonia, Diphtheria, Legionnaires’ disease, Meningitis and Mycobacterium tuberculosis. Chlamydial Pneumonia infection is caused by the bacteria Chlamydophila pneumonia is caused by the Gram-negative chlamydiae are intracellular parasites which must grow and reproduce within the cells of the host. The infection mildly affects the sinus, pharynx, bronchus and part of the lower respiratory tract. Its symptoms include fever, coughing, sore throat and pain in swallowing. Most adults have antibodies to this bacterium therefore providing a first line of treatment. Macrolides are also an effective treatment. Diphtheria is a contagious infection caused by the Gram-positive bacterium Corynebacterium diphtheria. The bacterium is transmitted through the air from nasopharyngeal secretions. Unvaccinated people and poor people living in crowded areas are the ones at most risk of contracting Diphtheria. Its signs include a thick yellowish nasal discharge containing mucus and pus. Treatment of the infection is usually through immunization of vulnerable population using Diphtheria vaccines.

Legionnaires’ disease is caused by a bacterium called Legionella pneumophila. It is part of microbial in natural ecosystems such as soil and freshwater and therefore it is found in shower stalls and air conditioning vents. Symptoms include high fever, respiratory secretions, headache and severe bronchopneumonia. Treatment begins with administration of erythromycin or rifampin drugs. Prevention of the disease is through elimination of the environmental sources of the bacterium. Mycoplasmal pneumonia is caused by the bacterium Mycoplasma pneumonia which is transmitted through air-borne droplets or close contact. The disease normally affects the upper respiratory tract gradually infecting the lower part including the lungs. Sighs include fever, headache and a persistent cough. Treatment involves administration of tetracycline or erythromycin drugs. Pertussis also commonly known as whooping cough is caused by a Gram-negative bacterium called Bordetella pertussis. Disease transmission occurs through bacterium droplets in the air. It is characteristically displayed by a prolonged cough which ends with a gasp or whoop. Treatment is with the use of a macrolide or Trimethoprimsulfamethoxasole.

Meningitis is a disease caused by a variety of Gram-positive and Gram-negative bacteria including Streptococcus pneumoniae and Neisseria meningitidis. The disease affects the brain and spinal cord meninges. It is very difficult to identify meningitis because symptoms might be present but test on specimen of cerebral fluid yield negative results. Signs include sore throat, respiratory illness, vomiting, headache, confusion and stiff neck and back. Common treatment is by vaccination and administration of antibiotics. Mycobacterium tuberculosis commonly known as Tuberculosis (TB) is caused by bacteria called mycobacterium tuberculosis. The infection comes about when the bacteria are phagoctyosed by macrophages in the lungs. The infection affects the lungs displaying symptoms such as fever, fatigue, sweeting at night and general body weakness. TB is treated with antimicrobial therapy with drugs such isoniazid, rifampin, ethambutol and pyrazinamide are administered within a period of six to nine months.

Streptococcal diseases (Group A) are a group of Gram-positive bacteria with Streptococcus pyogenes being of the most common. Streptococcal pharyngitis is also a frequently common bacterial infection. It is accompanied by a feeling of discomfort, headache and fever. Streptococcal infections are treated with penicillin or macrolide antibiotics. Poststreptococcal diseases which are common include glomerulonephritis and rheumatic fever. Glomerulonephritis affects the membranes of the kidney thus inhibiting the process of blood purification. The disease exhibits the following signs; edema, fever and hematuria. A kidney transplant or renal dialysis may be required if the disease develops to a chronic stage.

Bacterial diseases transmitted by Arthropods

Bacteria cause arthropod-borne diseases to human beings. Historically (plague, typhus) had emerged and terrorized human beings for many decades. Bacterial Arthropod-borne diseases include Lyme disease, Plague and Rocky Mountain spotted fever. Lyme disease is caused by a bacterium Lyme borrellosis and commonly a transmitted by ticks. Rodents, domestic and wild animals are the host of this disease. Signs and symptoms of this disease are fatigue, headache, neurological abnormalities, heart inflammation and arthritis in major joints such as knees and elbows. Prevention and controls of Lyme disease involves environmental cleanliness so as to clear tick and mite habitat and making sure domestic animals are well treated against parasite infestation. The Plague is caused by Gram-negative bacterium Yersinia pestis. It is transmitted from an infested rodent to human beings through direct contact, bites by an infected flea or breathing in of contaminated air-borne droplets. Symptoms include hemorrhages, fever, chills, exhaustion and swollen lymph nodes. Prevention and control involve flea and rodent containment in addition to vaccination using USP plague vaccine. Rocky Mountain spotted fever is caused by Rickettsia. The disease is common in tick infested areas with the wood tick and dog tick being the primary vectors. The Rocky Mountain spotted fever appears on the wrist and ankles signaled by sudden headaches, chills, very high fever and skin rashes. If the disease is not treated the bacteria destroys the blood vessels in important organs in the body such as the heart, lungs and kidney causing death within one week. The best means of treatment is by avoiding tick infested areas and treating domestic animal against tick infestation.

Direct Contact Bacterial infections

Most of the direct contact infection affect the skin and severe on occasion penetrate the skin affecting the underlying tissue. Some of the well-known examples include Gas Gangrene, Group B Streptococcal disease, Trachoma, Tetanus and Peptic ulcer disease and gastric among others. Gas Gangrene (Clostridial Myonecrosis). Clostridium perfringens are Gram-positive bacterium found in soil worldwide. Transmission is by coming in contact of injured skin tissue with the contaminated soil. Clinical signs include edema, severe pain and muscle necrosis. Treatment is through extended surgical removal of all infected dead tissue and administration of antitoxin and antimicrobials. Further, amputation of the infected limb may be required to prevent the spread of the disease.

Group B Streptococcal disease is caused by Streptococcus agalactiae which is a Gram-positive bacterium that causes sickness to infants and expectant women and the elderly. It is estimated to be the leading cause of meningitis and pneumonia among new born babies. Carriages of this disease are the vagina and the rectum. The infection is usually treated with an intravenous penicillin or ampicillin injection. A vaccine for the disease also exist, although it has been established as problematic due to antigen-shifting serotypes. Mycobacterial skin infections are caused by pathogenic species of nontuberculous which infest the soft tissue of the skin. Leprosy, one of the most common example, is caused by Mycobacterium leprae. It affects the skin of the patient over a long period of time like three to five years resulting in severe disfiguring. The most common symptom is the appearance of a round slightly pigmented skin eruption. Treatment is by administering drugs such as rifampicin with clofazimine which act in prevention of the synthesis of dihydrofolic acid which causes the pigmentations. Leprosy can be easily controlled through fast identification and treatment of patients.

Peptic ulcer disease is caused by a Gram-negative bacterium which is spiral-shaped called bacillus Helicobacter pylori. The bacteria infect the gastric mucus-secreting cells. H. pylori is treated using proton pump inhibitors which decrease the amount of stomach acid and antibiotics called metronidazole and tetracycline, amoxicillin or clarithromycin to kill the bacteria. Staphylococcal disease invades the respiratory tract, skin, intestine and vagina. These bacteria cause pus-forming disease such as boils, carbuncles abscesses and impetigo contagiosa. Due to the wide variety of staphylococcal infection there is no specific means of prevention but can be controlled through cleanliness and good hygiene of the lesions.

Sexually transmitted Diseases

STDs are diseases that are transmitted between individuals through sexual contact. Some microorganisms which cause STDs are also transmitted through non sexual means such injection using contaminated hypodermic needles and syringes. Some of the common bacterial STDs include Chlamydial disease, Gonorrhea and Syphilis. Chlamydial disease is transmitted through anal, oral and vaginal sex. The disease is caused by the bacteria of the species C. trachomatis. In males the signs include urethral discharge, itching and burning sensation when urinating. Further complications such as swelling of the reproductive organs may occur. Some of the symptoms in women include vaginal discharge and burning urination. The disease is severe in females than in males and may spread from the cervix to the fallopian tube and the rectum as well. Chlamydia is usually treated using macrolide or doxycycline drugs.

Gonorrhea is a STD that affects the mucous membranes. Membranes attacked can be of the genitourinary tract, eye, rectum and throat of the infected. It is caused by the Gram-negative bacterium diplococcus Neisseria gonorrhoeae. It is displayed with the onset of urethral discharge of yellow creamy pus and itching painful urination in males. In females the cervix is the main point of infection with vaginal discharge a common occurrence. The bacterium can also affect the womb as well as other surrounding tissue. Gonorrhea can lead to eye infection for newborns which occurs when they pass though the infected birth canal making them blind. To prevent this infection erythromycin or silver nitrate is diluted and placed in the eyes of newborns. In adults gonorrhea is treated using a single injection of cephtriaxone.

Syphilis is caused by Treponema pallidum is transmitted through sexual contact with an infected person. It signs and symptoms include a small painless reddened ulcer on the reproductive organ. Treatment is easily administered using a single dose of long-acting benzathine penicillin or a two week dose of doxycycline for individuals who are allergic to penicillin.

Staphylococcal diseases affect the skin, intestine, vagina, and respiratory tract. Staphylococci belong to the pyogenic cocci Gram-positive bacteria. Staphylococci are classified into pathogenic and nonpathogenic strains with the coagulase-positive species being the most vital in this genus. Staphylococci are also divided into slime and nonslime producers. Neborn infants develop impetigo contagiosa caused by Group A streptococci. Staphylococcal scalded skin syndrome is caused by S. aureus that produce exfoliatin (exfoliative toxin). Toxic shock syndrome is another staphylococcal disease common in women who use tampons. Tampons facilitate the growth S. aureus that are toxin-producing. Methicillin-resistant Staphylococcus aureus (MRSA) are resistant to B-Lactum antibiotics. Healthy people can also acquire the disease.

Streptococcal diseases are primarily transmitted through the air but can also be passed through the skin if it is infected. Some of this type includes cellulitis, impetigo and erysipelas. Cellulitis is a diffuse infection spreading through the skin causing a swelling which is red with fluid accumulated inside. Impetigo is characterized by crusty lesions and vesicles surrounded by a red boarder on the face, commonly seen in small children. It is treated using a topical mupirocin and in severe cases penicillin. Erysipelas causes an inflammation on the skin with red painful and reddish patches that enlarge and thicken. The drug of choice for treatment of this disease is erythromycin and penicillin. Invasive streptococcal infections are at times life-threatening. The danger begins when GAS strains find their way through a mucus membrane to wounds and eventually destroying the skeletal system. Tetanus is caused by the bacterium Clostridium tetani commonly found in soil and dust. It is transmitted through skin wounds. Prevention is done through the use of tetanus toxoids and immunization with administration of penicillin for treatment. Trachoma is a contagious disease caused by Chlamydia trachomatis bacteria that causes blindness. It is transmitted through contact of items such as soap and towels. Treatment may involve surgery if the patient reaches the blinding stage and if while still at infection stage, doxycycline, macrolides or tetracycline drugs are administered.

Bacterial disease caused by contaminated water and food

Food and water can be contaminated by many microorganisms thus causing disease to the digestive tract. These include cholera, Botulism, Campylobacter jejuni Gastoenteritis and Escherichia coli Gastoenteritis. Cholera is a disease caused by a bacterium called Vibrio cholera. It is transmitted by eating food or taking water having feces contaminants from an infected person. The disease is characterized by rapid loss of body fluids through vomiting and diarrhea causing dehydration and shock. Treatment is by oral rehydration therapy with inoculation with stimulate water. Doxycycline or tetracycline antibiotic may also be administer.

Botulism is a type of food poisoning that results from ingesting the preformed botulinum toxin commonly found in home-canned food. Clostridium botulinum is the bacteria responsible for this infection. The infection displays signs such as nausea, difficulty in speaking and swallowing, muscle weakness and vomiting. Treatment relies on polyvalent antitoxins. Campylobacter jejuni gastroenteritis is an infection caused by Campylobacter jejuni. The bacterium invades the small intestines causing swelling and secreting exotoxin in the process. The disease is treated by administration of laboratory fluids and electrolyte replenishing. Escherichia coli gastroenteritis also known as travelers’ diarrhea is caused by the E. coli bacteria. It affects the digestive system with the kidney being its prime target. Treatment is with fluid electrolyte in addition with doxycycline and trimethoprim-sulfamethoxazole. Salmonellosis caused by Salmonella gastroenteritis which arise from intestines of birds. It contaminates food causing intestinal discomfort. Shigellosis is caused by four species of bacteria of genius Shigella. It results in diarrhea and an acute swelling of intestinal tract. Prevented through proper personal hygiene and ensuring clean water supply. Staphylococcal food poisoning is caused by consumption of food that is not cooked or stored properly. Treatment is keeping hydrated while the body gets rid of the toxins.

Zoonotic bacterial diseases

These diseases are passed from animals to human beings through bacteria. Some bacteria begin as normal parasites to animals but they often evolve to cause diseases to human beings. Some of them include Anthrax, Brucellosis, Pssitacosis, Q fever and Tularemia among others. Anthrax is an infectious disease passed from infected animal such as cattle, goats and sheep to human beings directly. It is caused by the bacterium Bacillus anthracis. The bacterium can enter the human body through a cut on the skin, inhaling of spores or if the spores reach the gastrointestinal tract. Treatment of anthrax is effective is detected and begun early. Drugs such as ciprofloxacia or doxycycline are usually issued.

Brucellosis caused by bacteria of the genus Brucella transmitted through consumption of contaminated animal products such as milk and meat. Its symptoms include fever, headache and muscular pain. Usually treated with doxycycline and rifampin drugs with prevention involving consumption of properly sanitized and treated animal products. Psittacosis is a worldwide infection that is transmitted from birds to humans. It is caused by Chlamydophila psittaci whereby humans contact the disease by inhaling or handling waste of infected birds. Doxycycline or tetracycline therapy is a viable means of treatment. Q fever is caused by the y-proteobacterium Coxiella burnetti. In humans it is characterized by severe headache, confusion, sore throat, sweating, nausea and chest pains. Prevention involves vector control and proper public education. Tularemia is caused by the Gram-negative bacterium Fracisella tularensis. It is transmitted through coming in contact with infected animals or ingestion of contaminated food and water. Treatment is by streotimycin, tetracycline or aminoglycoside for three weeks.

Opportunistic bacterial infections

Antibiotic –associated colitis is a broad spectrum infection resulting from the overgrowth of clostridium difficile. Common symptoms include watery diarrhea, fever, nausea abdominal pain and loss of appetite. Treatment is by oral ingestion of metronidazole or vancomycin. Bacterial vaginosis is caused by Gardnerella vaginalis. The bacteria reside in the vagina and rectum of women. It is believed to be transmitted through intimate contact. It is signaled by fish-smelling discharge with a bit of pain and itching. Treatment is by a drug called metronidazole which kills anaerobic streptococci.

Dental diseases

These diseases are usually caused by dental pathogens and are characterized by tooth decay and bleeding gums. Dental plaque is formed by the bacterium Streptococcus gordonii. The bacteria are bound to the tooth forming a plaque further producing lactic acid from sucrose and other sugars. The acid eats up the enamel to produce lesions which induce tooth decay. Dental plaque can only be prevented since there is no cure. Brushing, flossing and rinsing with mouth wash. Periodontal diseases are all the infections that affect the periodontium. The disease is initiated by the formation of plaque resulting in tissue damage. The disease can be controlled by frequent plaque removal accompanied with proper tooth hygiene.

Streptococcal pneumonia is considered an opportunistic infection because it infected out of an individual’s own microbiota. The Gram-positive bacterium called streptococcus pneumoniae affects the upper respiratory tract. The disease is usually vaccinated with pneumococcal conjugate vaccines as a prevention measure.

Reference

Chapter 39; Human Diseases Caused By Bacteria