Chapter 6 Micro-organisms - PowerPoint Presentation

Chapter 6 Micro-organisms and Their Control

Pathogenic Bacteria Gram Positive Cocci Staphylococcus aureus Superficial infections of the skin such as boils, abscesses and impetigo; Can cause serious infections such as osteomyelitis, septicemia, endocarditis, and pneumonia Important cause of health care associated infections Depending on site attacked signs and symptoms will vary Able to adapt to antimicrobials and become resistant; MRSA-is resistant to most antibiotics; can spread easily between patients; staff can become colonized and may become a reservoir

Pathogenic Bacteria Gram Positive Cocci Staphylococcus epidermidis Associated with infections caused by invasive plastic or metal devices, including peritoneal dialysis, catheters, arterial grafts, cardiac prosthetic valves or prosthetic orthopedic joints. Responsible for bloodstream infections and or particular vulnerability are the immunocompromised patients.

STREPTOCOCCI Puerperal Sepsis Frequent complication after childbirth It is not as common nowadays but still can be serious infection if does happens Acute rheumatic fever or glomerulonephritis occur after a group A streptococcal infection-because hypersensitivity reaction and end up destroying muscles in the heart, or the valves, or kidneys

Pathogenic Bacteria Gram Positive Cocci Streptococcus pneumonia ( pneumonococci ) Arranged by pairs Increase risks for the very young and old Transmission by aerosol/droplets and by contact with secretions Cross infection can present a problem among the elderly or immunocompromised Pneumonia vaccination is recommended for infants, adults over 65, and those with chronic system illnesses such as cardiac or pulmonary diseases Penicillin, an antibiotic, is drug of choice

Pathogenic Bacteria Gram Positive Bacilli Bacillus Aerobic forms spores Found in soil, water, and dust Bacillus anthracis causes anthrax Bacillus cereus causes food poisoning in milk, rice, and pasta Clostridium tetani Tetanus likely to occur in wounds contaminated with soil or foreign body in deep puncture Tetanus vaccination available not spread from person to person

Pathogenic Bacteria Gram Positive Bacilli Clostridium difficile Symptoms will include mild diarrhea to severe diarrhea Stool sample will identify the toxin Will occur at times when given antibiotic therapy, especially clindamycin, cephlasporins, and quinolones Other risk factors in chemotherapy, GI interventions such as surgery or tube feedings and reduction of gastric pH Infection control measures will include Contact precautions

Pathogenic Bacteria Gram Positive Bacilli Listeria-found in soil and feces of a variety of animals Causes mild influenze like illness Infection during pregnancy can cause premature delivery, septicemia, meningitis in neonate Immunocompromised patients also at risk Most infections acquired by consumption of contaminated food Soft cheeses, coleslaw, salads, prepared sandwiches, fruit, cooked meats Found in a variety of chilled foods Destroyed by pasteurization

Pathogenic Bacteria Mycobacterium tuberculosis Usual site of infection is lungs-known as pulmonary tuberculosis A chronic, progressive infection Are unusual in that ingested by phagocytic cells but instead is able to reproduce within the cell and multiply Will leave a calcified lesion in lungs visible in CXR Remain dormant in lesions and eventually start to multiple and the disease reactivates Classic signs fever, night sweats, loss of appetite, weight loss and lethargy

Pathogenic Bacteria Mycobacterium tuberculosis Lesions enlarge and form cavities filled with pus that spread to cavities and coughed up in sputum Spread through droplets and infects lungs most often May spread to other areas in the body Secondary cases occur in close contacts who spend hours together Treatment is complex; inadequate or incomplete treatment is the cause of relapse and can facilitate emergence of multidrug resistant strains; Mantoux testing is done to determine exposure

Pathogenic Bacteria Neisseria Neisseria gonorrhea-sexually transmitted; affects genitourinary tract, may also occur in anal canal, throat, and eyes; newborns may become infected during birth from vaginal canal; there are now penicillin resistant strains are becoming prevalent

Pathogenic Bacteria Escherichia coli (E coli)-normal in the gut flora; foodborne; can be transmitted via contaminated food, baby milk and water, or hands Symptoms can be from mild diarrhea to hemorrhagic colitis with bloody diarrhea and severe abdominal pain Usually resolves within a few days Outbreaks have been linked to ingestion of undercooked meat, bathing in contaminated water, and handling of animals

Pathogenic Bacteria Salmonella Can cause food poisoning Cause enteric fever; can colonize in the gallbladder Outbreaks have been associated with shellfish grown in polluted areas Infections are usually derived from poultry; can be contaminated raw food cross contamination

Pathogenic Bacteria Shigella-cause dysentery, a gastrointestinal infection, characterized bloody mucopurulent stools Direct physical contact where hands have not been washed after using bathroom and having a bowel movement; also has been spread indirectly by contamination of food

Pathogenic Bacteria Helicobacter Spiral shaped micro-organisms that can cause gastritis and ulcers; duodenal ulcers are many times infected with Helicobacter pylori Can be cured by antimicrobial therapy

Pathogenic Bacteria Chlamydia Microorganisms cannot live outside the cells of the host Different strains can cause sexually transmitted diseases Can cause urethritis in males and pelvic inflammatory disease in females Infants when born that contract the microorganisms can have pneumonia

Fungal Infections Candida-caused by Candida albicans-found in normal flora of the mouth, intestinal tract, and vagina It is a superficial infection of mucous membranes or skin Can be found in neonates and debilitated adults or those that have received broad spectrum antibiotic therapy; immunocompromised or seriously ill can cause systemic infections such as bloodstream infections, endocarditis, and abscesses Can be established in invasive devices such as IV and urinary catheters

Fungal Infections Dermatophytes (Ringworm or Tinea) Cause superficial infection of the skin, hair, and nails Include athlete’s foot and ringworm of the body or scalp Pneumocystis-colonizes in the lungs of healthy people but in inmmunocompromised causes a severe pneumonia

Viral Infections Herpes Viruses-include Herpes Simplex types 1 and 2, Epstein-Barr virus, varicella zoster virus, and cytomegalovirus-all strains can lie latent, causing repeated episodes of infection when reactivated Herpes Simplex Virus 1-HSV 1 occurs in infancy and early childhood; remains dormant in local nerve cells periodically can come back as vesicles on the lip and recurrent eye infections Herpes Simplex Virus 2-HSV 2-occurs mostly in adults causing genital herpes lesions affecting the penis in the male and the vulva, labia, and cervix in females Transmitted by direct contact with lesions

Viral Infections Varicella Zoster Virus-causes chickenpox; mild in children, but in adults may be complicated by pneumonia can cause serious disease; immunocompromised people may also develop a severe disseminated infection; virus is secreted in the characteristic vesicles on the skin, but is primarily a respiratory tract and is in the respiratory secretions The virus travels along the sensory nerves and remains dormant in the ganglion for prolonge periods; if reactivated can travel the nerve pathways and erupt as vesicles known as shingles

Viral Infections Viral Hepatitis-inflammation of the liver, some infectious and non-infectious Hepatitis A and E are transmitted by fecal-oral route Hepatitis B and C are bloodborne Hepatitis D is not really a true virus but can cause a severe, acute hepatitis if it infects and individual already infected with or carrying Hepatitis B virus Can cause malaise, nausea, and after a few days also jaundice

Viral Infections Hepatitis B-most infections mild but some can result in extensive liver damage and liver failure that could be fatal. , common symptoms that may occur are jaundice, nausea, vomiting, joint pains, rashes, and marked elevations of liver function tests. Incubation is between 2 to 3 months or could be as long as 6 months; groups are at increased risk prisoners, IV drug users who share needles Surface antigen HBsAg is found on the outer protein coat of the virus and its presence in blood indicates an active infection Presence of anti- Hbe in the blood indicates a low infection HBV is transmitted by sexual intercourse and mother to baby Also transmitted by blood, body fluids, and semen and vaginal fluids

Viral Infections Healthcare workers are more likely to be infected by HBV than others because of the close contact with body fluids Hepatitis B Immunization Vaccine is effective method of protecting against infection It is a course of three injections can provide protection for a period of years. Specific immunoglobulin HBIg can be used to provide immediate temporary protection but needs to be administered within 48 hours of exposure

Viral Infections Hepatitis C-primary infection is mild and often asymptomatic and rarely associated with jaundice. Those infected can become chronic carriers; those with chronic infection can develop liver disease, liver cancer, or cirrhosis of the liver without treatment with antiviral drugs Healthcare workers are at risk from needlesticks, risk is lower than HBV There is not a vaccination for Heptitis C Hepatitis D can only replicate with HBV Hepatitis G is most recently identified also known to be transmitted by blood transfusions, needlesticks

Viral Infections HIV-is a retrovirus; diagnosed by detecting antibodies to the virus in the blood; usually not detectable until 3 months after exposure at which point they have seroconverted Virus attacks the CD4 that is on T lymphocytes and other immune cells Immune system is deficient allowing other opportunistic infections to be able to flourish such as pneumocystis jiroveci Remember healthcare workers are always at risk of being exposed to any BBV and any other disease process.