Week 4_Microbiology and anti-inflammatory Drugs (Student Copy) PDF

Nursing 2700: Integrated Nursing Sciences I Infection An infection is an invasion of the body by a pathogen/microorganism and the resulting signs and symptoms that develop in response to the invasion Microorganisms are everywhere! Most common causes of infection are bacteria, fungi,...

Nursing 2700: Integrated Nursing Sciences I Infection An infection is an invasion of the body by a pathogen/microorganism and the resulting signs and symptoms that develop in response to the invasion Microorganisms are everywhere! Most common causes of infection are bacteria, fungi, protozoa, viruses Many can grow in artificial culture medium Infections are classified as localized (limited to a small area) or systemic (widespread throughout the body, often spread via the blood) Bacteria Bacteria are one-celled microorganisms that are found virtually everywhere on earth and are involved in fermentation, putrefaction, infectious diseases, and nitrogen fixation Can be harmful or beneficial Non-pathogenic – usually do not cause disease unless conditions change, part of normal flora, often beneficial Pathogens – disease-causing microbes Bacteria Individuals are able to Bacteria cause disease in two remain healthy and ways: resistant to infectious They can enter the body and grow microorganisms because of inside human cells (e.g., tuberculosis certain host defenses [TB]) Physical barriers – intact skin They can secrete toxins that or ciliated respiratory mucosa damage cells Physiological defenses – Exotoxins – usually produced by gastric acid in stomach or gram-positive bacteria immune factors (antibodies) Endotoxins – present in the cell Phagocytic cells wall of gram-negative bacteria; (macrophages and released on death of bacterium; polymorphonuclear vasoactive compounds that can neutrophils) cause septic shock Enzymes – damage tissues and promote spread of infection Bacteria Bacteria may take a number of different shapes (known as morphology) Grouped based on their shape Bacilli Rod-shaped organisms Spirochetes Include spiral forms and vibrio Cocci Spherical forms Diplococci Streptococci Bacteria Classified as prokaryotes No nuclear membrane – no nucleus Function metabolically and reproduce Divide by binary fission Complex cell wall structure Do not require living tissues to survive Vary in size and shape Bacteria Most important way to categorize bacteria is on the basis of their response to the Gram stain procedure Significant as it guides the choice of antibiotic therapy Gram-positive bacteria: purple Thick cell wall Thick outer capsule Gram-negative bacteria More complex cell wall structure Makes it more difficult to treat Drug molecules have a hard time penetrating cell wall Bacterial Infection Host defenses compromised  susceptible to infection Microorganism invades and multiplies in body tissues Infectious process can overwhelm the body’s defense system  infection becomes clinically apparent Classic signs and symptoms Fever Chills Sweating Redness Local vs. systemic S&S Pain and swelling Increased WBC Formation of pus  Common Disease-Causing Bacteria Type Diseases Caused Proteus organisms Clostridium organisms Pseudomonas aeruginosa Urinary tract infections, meningitis C. botulinum Food poisoning with progressive muscle Salmonella organisms paralysis S. typhi Typhoid fever C. difficile Diarrhea, colitis C. perfringens Food poisoning, gangrene Other Salmonella organisms Food poisoning, gastroenteritis C. tetani Tetanus (lockjaw) Shigella organisms Corynebacterium Diphtheria Staphylococcus aureus Shigellosis, diarrhea with abdominal pain and diphtheriae fever (dysentery) Escherichia coli Urinary tract infections, cystitis, peritonitis, Skin infections, pneumonia, urinary tract inflammatory gastrointestinal infections infections, acute osteomyelitis, toxic shock Haemophilus organisms syndrome H. aegyptius Pink eye Streptococcus organisms H. influenzae Nasopharyngitis, meningitis, pneumonia, otitis S. epidermidis Nosocomial sepsis media, upper respiratory tract infections S. faecalis Genitourinary infection, infection of surgical H. pertussis Pertussis (whooping cough) wounds Helicobacter pylori Peptic ulcers, gastritis S. pneumoniae Pneumococcal pneumonia, otitis media Klebsiella and Urinary tract infections, peritonitis, pneumonia S. pyogenes (group A β- Pharyngitis, scarlet fever, rheumatic fever, Enterobacter organisms hemolytic streptococci) acute glomerulonephritis, erysipelas, Legionella pneumophila Pneumonia (Legionnaires’ disease) pneumonia, upper respiratory tract Mycobacterium organisms infections M. leprae Hansen’s disease (leprosy) S. pyogenes (group B β- Urinary tract infections M. tuberculosis Tuberculosis hemolytic streptococci) Neisseria organisms S. viridans Bacterial endocarditis N. gonorrhoeae Gonorrhea, pelvic inflammatory disease Treponema pallidum Syphilis N. meningitidis Meningococcemia, meningitis Vibrio cholerae Cholera Antibiotic Therapy Antibiotics are most effective when their actions are combined with functioning bodily defense mechanisms Overall goal of antibiotic therapy is to interfere with metabolism or structure of the organism so that it cannot survive or reproduce Microbicidal – kills microbes and normal floral (potential for superinfection) Microbiostatic – reversibly inhibits growth of bacteria Patients can become colonized with bacteria Colonization – bacteria present in open wounds, secretions, mucous membranes, and skin but patient does not have signs of infection Does not require antibiotic treatment If treated with antibiotics, can be one way in which drug-resistant organisms emerge Health Care-Associated Infection Community-acquired infection – An infection that is acquired by a person who has not been hospitalized (within the past year) or had a medical procedure (e.g., dialysis, surgery, catheterization) within the past year Health care–associated infections Contracted in a health care facility Were not present or incubating in the patient on admission to the facility Occurs more than 48 hours after admission One of the top 10 causes of death in Canada More difficult to treat because causative microorganisms are often drug resistant and the most virulent Previously known as nosocomial infection Health Care-Associated Infection More common types of health care- associated infections are Central-line associated bloodstream infections Catheter-associated urinary tract infections Surgical site infections Antimicrobial-resistant organisms (C. Difficile, MRSA, VRE) Community-acquired infections Other sources of infection Mechanical ventilators Intravenous infusion lines Dialysis equipment Multidrug-Resistant Organisms Organisms that are resistant to one or more classes of antimicrobial drugs Methicillin-resistant Staphylococcus aureus (MRSA) Vancomycin-resistant Enterococcus (VRE) Organisms producing extended-spectrum ß- lactamases (ESBLs) Organisms producing Klebsiella pneumoniae carbapenemase (KPC) Active surveillance testing by swabbing nares and/or rectal/perirectal area, depending on what organism you are testing Purpose is to appropriately place colonized patients into contact precautions to effectively provide a barrier between affected patients and healthcare workers Multidrug-Resistant Organisms MRSA Threat of MRSA becoming resistant to all antibiotics currently available No longer seen just in hospitals. It has spread to the community setting, and approximately 50% of staphylococcal infections contracted in the community involve MRSA VRE: usually seen in urinary tract infections (UTIs) Newer antibiotics have been developed to successfully treat VRE and MRSA Multidrug-Resistant Organisms Classes of Antibiotics Extended-spectrum ß-lactamases (ESBL) Organisms that produce ESBL are resistant to all ß-lactam antibiotics and aztreonam Can be treated only with carbapenems or sometimes quinolones However, some bacteria have become resistant to carbapenems too. These bacteria, like Klebsiella pneumoniae, have developed a new way to resist the drugs, which is called Klebsiella pneumoniae carbapenemase (KPC). In difficult cases where bacteria are resistant to carbapenems, we may use other antibiotics like tigecycline or colistimethate sodium. Health Care-Associated Infection Over 70% of health care-associated infections are preventable Most commonly transmitted by direct contact Handwashing: single most important prevention Disinfectant method! Antiseptic Generally only inhibits the growth of Kills organisms microorganisms; does not Used only on necessarily kill them Applied exclusively to living nonliving objects tissue Cidal agent Static agents General Principles of Antibiotic Therapy Antibiotics have three general uses Patient assessed for signs and symptoms of infection Patient assessed during and after antibiotic to evaluate effectiveness monitor for adverse drug effects, and make sure infection not recurring Empiric therapy: treatment of an infection before specific culture information has been reported or obtained Definitive therapy: antibiotic therapy tailored to treat organism identified with cultures Prophylactic therapy: treatment with antibiotics to prevent an infection, as in intra-abdominal surgery or after trauma Culture specimens BEFORE therapy initiated, whenever possible General Principles of Antibiotic Therapy Culture and Sensitivity Sample sent to lab for testing (C&S) Blood, sputum, wound, urine, stool Sample analyzed for microorganism (culture) Sample tested for susceptibility to various antibiotics (sensitivity) Helps determine if correct antibiotic was selected or if it requires adjustment to be most effective Use most narrow-spectrum, least toxic drug based on results Typically takes 48-72 hours General Principles of Antibiotic Therapy Empiric Therapy Broad spectrum antibiotics – those that are effective against numerous organisms (gram-positive, gram- negative, anaerobic) Narrow spectrum antibiotics – effective against only a few organisms and avoids damage to normal flora Best to use an antibiotic that targets the specific organism identified Overuse of broad-spectrum antibiotics contributes to resistance General Principles of Antibiotic Therapy Prophylactic Therapy Prophylactic antibiotics should be given before a procedure 60 minutes before the incision Ensures adequate tissue penetration Type and length of antibiotics selected for prophylactic therapy depends on Risk of infection (GI surgery is higher risk) Patient factors (prosthetic heart valve + dental surgery) General Principles of Antibiotic Therapy Patient monitored continuously for therapeutic efficacy and adverse drug effects Therapeutic response – decrease in specific signs and symptoms of infection are noted (fever, elevated white blood cell count, redness, inflammation, drainage, pain) Subtherapeutic response – signs and symptoms of infection do not improve Incorrect route of drug administration, inadequate drainage of an abscess, poor drug penetration to infected area, insufficient serum levels of the drug, bacterial resistance Adverse effects can include itching, rash, fever, hives, chills, joint pain, difficulty breathing, wheezing, nausea*, General Principles of Antibiotic Therapy Superinfection Superinfection – occurs when antibiotics reduce or completely eliminate the normal bacterial and fungal flora that are needed to maintain the normal function in various organs When these microorganisms are killed, other bacteria or fungi are permitted to take over and cause infection Example – antibiotic use is strongly associated with the potential for diarrhea Antibiotic-acquired diarrhea is a serious superinfection when it causes antibiotic-acquired colitis (C. Difficile infection) toxic mega colin (so much inflammation that it burst, patient can die!!) Antibiotics disrupt the normal gut flora and cause an overgrowth of C. Difficile Odorous watery diarrhea, abdominal pain, fever Requires treatment for the superinfection General Principles of Antibiotic Therapy Antibiotic Resistance Many easily treatable bacterial infections have become increasingly resistant to antibiotic therapy Antibiotic resistance is a concerning public health problem Attributable to Overprescribing of antibiotics Non-adherence to antibiotic regimen (e.g., not completing the prescribed regimen because they are feeling better) Antimicrobial stewardship – institutional activity that includes ensuring appropriate selection, dosing, choice of route, and duration of antimicrobial therapy Therapy Food-Drug and Drug-Drug Interactions Common problem when antibiotics are taken Tetracyclines and quinolone antibiotics have common drug interactions with substances that chelate Calcium-containing substances – milk, cheese, antacids Vitamin/mineral supplements - iron, magnesium Important to assess  if antibiotics are not absorbed, treatment failure is likely A chemical compound that binds tightly to metal ions General Principles of Antibiotic Therapy Host Factors Age Allergy history Penicillin's and sulfonamides are two broad classes of antibiotic to which many people have allergic anaphylactic reactions Most common severe reactions: difficulty breathing; significant rash, hives, or other skin reaction; and severe gastrointestinal (GI) intolerance Kidney and liver function Pregnancy status Genetic characteristics Site of infection Viruses Small obligate intercellular parasites Protein coat or capsid- dictates how difficult they are. Protein coat comes in various shapes and sizes Can change (mutate) quickly Nucleic acid DNA or RNA (never both) Classification dependent on nucleic acid present Some RNA-containing viruses contain reverse transcriptase enzyme to convert RNA to DNA Can infect all types of cells Some viruses do not cause disease Virus Replication Viral replication A virus cannot replicate on its own It must attach to and enter a host cell It then uses the host cell’s energy to synthesize protein, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) Viruses are difficult to kill because they live inside the cells Any drug that kills viruses may also kill cells Life Cycle of Viruses Latent Viral Infection Viruses that are capable of remaining hidden or dormant inside the cell in a process called latency- latent viral infection!! Virus enters cell as with active infection Viral proteins are produced and inserted into membrane of host cell This may stimulate an immune response and destruction of host cell Example: the varicella-zoster virus infects many cells throughout the body and causes chickenpox, characterized by a rash of blisters covering the skin About 10 to 12 days postinfection, the disease resolves, and the virus goes dormant, living within nerve-cell ganglia for years During this time, the virus does not kill the nerve cells or continue replicating It is not clear why the virus stops replicating within the nerve cells and expresses few viral proteins but, in some cases, typically after many years of dormancy, the virus is reactivated and causes a new disease called shingles Examples of Viral Illnesses Type Diseases Caused Adenoviruses Upper respiratory tract infection, HIV HIV infection, AIDS pneumonia Influenza A and B Upper respiratory tract infection Arbovirus Syndrome of fever, malaise, headache, Mumps Parotitis, orchitis in postpubertal myalgia; aseptic meningitis; encephalitis males Coronavirus Upper respiratory tract infection Papovaviral Warts Coxsackieviruses Upper respiratory tract infection, Parainfluenza types Upper respiratory tract infection A and B gastroenteritis, acute myocarditis, aseptic 1–4 meningitis Parvovirus Gastroenteritis Ebola virus Viral hemorrhagic fever Poliovirus Poliomyelitis Echoviruses Upper respiratory tract infection, Poxviruses Smallpox gastroenteritis, aseptic meningitis Reoviruses 1, 2, 3 Upper respiratory tract infection Flaviviruses Yellow fever, Dengue, West Nile Respiratory Gastroenteritis, respiratory tract Hepatitis A, B, C, Viral hepatitis syncytial virus infection D, E Rhabdovirus Rabies Human herpes viruses Rhinovirus Upper respiratory tract infection, Cytomegalovirus Gastroenteritis; pneumonia and retinal pneumonia (CMV) damage in immunosuppressed individuals; Rotaviruses Gastroenteritis infectious mononucleosis-like syndrome Rubella German measles Epstein-Barr Mononucleosis, Burkitt’s lymphoma Rubeola Measles virus (possibly) West Nile virus Flulike symptoms, meningitis, Herpes simplex, Herpes labialis (“fever blisters”), genital encephalitis type 1 herpes infection Herpes simplex, Genital herpes infection Viral Illnesses Most viral illnesses are bothersome but survivable Effective vaccines have prevented some illnesses Effective drug therapy is available for a small number of viral infections- the antiviral drug attacks the cell as well Typically, viral illness requires symptomatic treatment/management Treat the symptoms the virus is causing Fever  antipyretic Sore throat  analgesic Headache  analgesic Malaise  rest Hydrate Fungi Very large and diverse group of microorganisms Includes yeasts and moulds Fungal infections are also known as mycoses Some fungi are part of the normal flora of the skin, mouth, intestines, and vagina Systemic, cutaneous, subcutaneous, and superficial Cutaneous, subcutaneous, and superficial: infections of various layers of the integumentary system (skin, hair, or nails) Fungi that cause integumentary infections are known as dermatophytes Systemic infections can be life threatening and usually occur in immunocompromised host Fungi Yeasts Moulds Single-cell fungi Multicellular Reproduce by budding Characterized by long, Can be used for: branching filaments Baking breads called hyphae Brewing alcoholic Can cause allergies beverages Produce disease-causing Can cause diseases like metabolites called vaginal yeast infection mycotoxins and oral thrush Used to make pharmaceuticals (e.g., penicillin) Mycotic Infections – Most common Candida albicans May follow antibiotic therapy, antineoplastics, or immunosuppressants (corticosteroids) May result in overgrowth and systemic infections Growth in the mouth is called thrush or oral candidiasis Common in newborn infants and immunocompromised patients Vaginal candidiasis Yeast infection Pregnant women, women with diabetes, women taking oral contraceptives Common Disease-Causing Fungi Organism Diseases Caused Organs Affected Aspergillus fumigatus Aspergillosis Otomycosis Lungs, ears Blastomyces dermatitidis Blastomycosis Lungs, various organs Candida albicans Candidiasis Vaginitis Thrush Intestines, vagina, skin, mouth Coccidioides immitis Coccidioidomycosis Lungs Pneumocystis jiroveci Pneumocystis pneumonia Lungs Sporothrix schenckii Sporotrichosis Skin, lymph, vessels Trichophyton species Tinea pedis Skin Microsporum species Tinea capitis Skin Epidermophyton species Tinea corporis Skin  Inflammation Localized protective response stimulated by injury to tissues, which serves to destroy, dilute, or wall off (sequester) both the injurious agent and the injured tissue Pain, fever, loss of function, redness, and swelling Endogenous compounds, including proteins of the complement system, histamine, serotonin, bradykinin, leukotrienes, and prostaglandins Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) A large and chemically diverse group of drugs that Indications have: Analgesic activities Relief of mild to moderate Anti-inflammatory activities headaches Relief of myalgia Antipyretic activities Relief of neuralgia aspirin-platelet inhibition Relief of arthralgia Relief of postoperative pain Properties all NSAIDs share: Relief of pain associated with Antipyretic properties arthritic disorders such as Analgesic properties rheumatoid arthritis, juvenile Anti-inflammatory properties arthritis, ankylosing spondylitis, and osteoarthritis Treatment of gout and hyperuricemia NSAID Classifications NSAIDs Mechanism of Action NSAIDs act through inhibition of the leukotriene pathway, the prostaglandin pathway, or both NSAIDs relieve pain, headache, and inflammation by blocking the chemical activity of the cyclooxygenase (COX) enzymes There are at least two types of cyclooxygenase Cyclooxygenase-1 (COX-1) is the isoform of the enzyme that promotes the synthesis of prostaglandins, which have primarily beneficial effects on various body functions Cyclooxygenase-2 (COX-2) isoform promotes the synthesis of prostaglandins that are involved in inflammatory processes NSAID Classifications and Examples Cyclo- Acetic acid oxygenase Enolic acid Propionic acid Salicylates derivatives (COX)-2 derivatives derivatives inhibitors aspirin diclofenac celecoxib nabumetone flurbiprofen diflunisal sodium (Celebrex®) meloxicam ibuprofen (Voltaren®) (Mobicox®) (Motrin®, indomethacin piroxicam Advil®) sulindac ketoprofen etodolac (Apo-Keto-E®) ketorolac naproxen (Toradol®) (Naprolen®, mefenamic Naprosyn®, acid Aleve®) (Ponstan®) oxaprozin tiaprofenic acid Simple Nursing – NSAIDs for NURSES Aspirin* Aspirin promotes bleeding by inhibiting platelet aggregation Platelets are unable to replace aspirin-inactivated COX, and hence bleeding time is prolonged for the life of the platelet Taking two 325-mg aspirin tablets can double bleeding time for about 1 week Aspirin is contraindicated for patients with bleeding disorders There is no need to stop using aspirin before procedures with a low risk for bleeding (e.g., dental, dermatologic, or cataract surgery) 81-mg of Aspirin daily is used for primary prevention of MI or stroke NSAIDs and Kidney Function Kidney function depends partly on prostaglandins Disruption of prostaglandin function by NSAIDs is sometimes strong enough to precipitate acute or chronic kidney injury or failure Use of NSAIDs can compromise existing kidney function Kidney toxicity can occur in patients with dehydration, heart failure, or liver dysfunction, or with the use of diuretics or angiotensin-converting enzyme inhibitors NSAIDs Health Canada Warning All NSAIDs (except aspirin) share a Health Canada warning regarding an increased risk of adverse cardiovascular thrombotic events, including fatal MI and stroke NSAIDs cause an increased risk of serious GI adverse events Older adults are at greater risk NSAIDs Interactions Serious interactions can occur when given with: Alcohol Anticoagulants acetylsalicylic acid (ASA) Biphosphonates Corticosteroids and other ulcerogenic medications Protein-bound drugs Diuretics and angiotensin-converting enzyme inhibitors Other drugs Examples of NSAIDs ibuprofen (Motrin, Advil) Most commonly used NSAID Uses: analgesic effects in the management of RA, OA, primary dysmenorrhea, dental pain, musculoskeletal disorders; antipyretic actions naproxen Second most commonly used NSAID Somewhat better adverse effect profile than ibuprofen Fewer drug interactions with angiotensin-converting enzyme inhibitors given for hypertension Higher risk for misuse due to overconsumption Examples of NSAIDs indomethacin Analgesic, anti-inflammatory, antirheumatic, and antipyretic properties Uses: therapy for rheumatoid arthritis (RA), osteoarthritis (OA), acute bursitis or tendonitis, ankylosing spondylitis, acute gouty arthritis Oral and rectal routes ketorolac tromethamine (Toradol) Some anti-inflammatory activity Used primarily for its powerful analgesic effects, which are comparable to those of narcotic drugs such as morphine sulphate Indication: short-term use (up to 5 to 7 days) to manage moderate to severe acute pain Adverse effects: kidney impairment, edema, GI pain, dyspepsia, and nausea Examples of NSAIDs celecoxib (Celebrex®)- only cox 2 inhibitor on the market First and only remaining COX-2 inhibitor Indicated for OA, RA, acute pain symptoms, ankylosing spondylitis, and primary dysmenorrhea Adverse effects include headache, sinus irritation, diarrhea, fatigue, dizziness, lower-extremity edema, and hypertension Little effect on platelet function Not to be used in patients with known sulpha allergy Drug Study Activity Let’s break up into groups Each group will be assigned a NSAID Indomethacin Ketorolac Ibuprofen Naproxen Celecoxib Complete a drug study on your assigned drug Upload your drug study to the discussion board on D2L Nursing Implications Before beginning therapy, observe for and assess conditions that may be contraindications to therapy, especially, GI lesions or peptic ulcer disease Bleeding disorders Observe for and assess conditions that require cautious use Perform laboratory studies as indicated (cardiac, kidney, and liver function studies; complete blood count; platelet count) Perform a medication history to assess potential drug interactions  Acute and potentially life-threatening condition involving Nursing progressive neurological deficits that can lead to coma and may also involve liver damage Triggered by viral illnesses such as influenza, as well as by salicylate Implications therapy itself in the presence of a viral illness Survivors of this condition may or may not have permanent neurological damage Do not give salicylates to children and teenagers because of the risk of Reye’s syndrome Because these medications generally cause GI distress, they are often better tolerated if taken with food, milk, or an antacid to avoid irritation Explain to patients that therapeutic effects may not be seen for 1 week or more Educate patients about the various adverse effects of NSAIDs, and instruct them to notify their prescribers if these effects become severe or if bleeding or GI pain occurs Instruct patients to watch closely for the occurrence of any unusual bleeding, such as in the stool Nursing Implications Advise patients that enteric-coated tablets should not be crushed or chewed Monitor therapeutic effects, which vary according to the condition being treated Decrease in swelling, pain, stiffness, and tenderness of a joint or muscle area