Module 7: Antimicrobial Selection & Respiratory Infections Flashcards by Mr. Bobbits

Cu____e (24 hours)

Most definitive method for diagnosis and treatment of an infection
Sites tested determined by suspected site of infection (urine, blood, CSF, sputum, etc.)
Provides initial identification of organism by gram stain, growth on selective media, presence or absences of enzymes, and chemical characteristics.

Culture

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A G___ s____ is used to classify bacteria into Gram + or Gram - based on the organisms ability to retain stain (either purple/blue or red), indicating the makeup of it’s cell wall. The staining also allows for visualization of the organism and morphology (cocci, rods, etc). This is usually the first test performed on a culture of a potentially infectious site. It allows practitioners to streamline antibiotic therapy initially.

Gram stain

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Regarding Gr__ st___s:

It is essential to know organism morphology and what organism are “typically” associated with infections at a given site. With this information, antibiotic selection can be made based on susceptibility, location (can we achieve appropriate concentrations?) and patient factors.
Eg. (see discussions) S. pneumoniae [Gm+ diplococci] and H. influenza [gm - coccobacilli] are pathogens typically associated with CAP.

Gram stain

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Coloni______:

organisms do not invade the host but are part of the normal flora (Microorganisms that normally reside at a given site).

Colonization

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Examples of col________n:

The small and large intestine normal flora includes many organisms such as: lactobacillus, streptococcus, enterococcus, Enterobacteriaceae, Peptostreptococcus, Bacteroides and anaerobes.
Staphylococcus species are common skin flora and are not found in the normal flora of the GI tract (so it’s presence there would be pathogenic)
The presence of large numbers of epithelial cells (from the skin) would indicate contamination

Colonization

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I________:

organisms invade the host and patient has s/Sx’s of infectious process

Infection

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Cont_______:

the isolated organisms came from the patient’s skin or the environment.

Contamination

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V________:

The ability of an agent of infection to produce disease. The v________ of a microorganism is a measure of the severity of the disease it causes.

virulence

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Pathog_______ refers to the ability of an organism to cause disease (ie, harm the host). This ability represents a genetic component of the pathogen and the overt damage done to the host is a property of the host-pathogen interactions. Commensals and opportunistic pathogens lack this inherent ability to cause disease. However, disease is not an inevitable outcome of the host-pathogen interaction and, furthermore, pathogens can express a wide range of virulence.

Pathogenicity

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V________, a term often used interchangeably with pathogenicity, refers to the degree of pathology caused by the organism. The extent of the this is usually correlated with the ability of the pathogen to multiply within the host and may be affected by other factors (ie, conditional). In summary, an organism (species or strain) is defined as being pathogenic (or not), and depending upon conditions, may exhibit different levels of this.

Virulence

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Sensitivity of organism to antimicrobial agent

M__: Lowest concentration of drug that will inhibit visible growth
M__: Lowest concentration of drug that fails to show growth or results in 99.9% reduction of the initial inoculum

MIC

MBC

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Antibacterial combinations:

S______: Greater activity than the sum of activity of either agent alone
A_________: Activity that is worse than either agent alone
A______e/I_________t: Activity that is neither synergistic or antagonistic

Synergy

Antagonism

Additive/Indifferent

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Post-antibiotic effect

Persistent suppression of bacterial growth after brief exposure to the antibiotic

Post-antibiotic effect

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“Time dependent killers”

killing is dependent on the time an organism is in contact with the drug

“Time dependent killers”

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“Concentration dependent killers”

killing is dependent on the concentration of the drug that the organism is exposed to

“Concentration dependent killers”

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Steps of bacterial infection:

Bind: to electrochemically complementary tissue
Colonize: exponential growth
Produce: toxins and enzymes

Steps of bacterial infection

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Mechanisms of bacterial res_______ (the ability of a microbe to resist the effects of medication previously used to treat them) causing antibiotics to be ineffective:

Porin channels adapt to prevent drug entry
Drug-metabolizing enzymes, e.g., beta-lactamases
ATP driven P-glycoprotein efflux pumps
Changes in drug binding proteins, e.g., for β-lactams

resistance

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(Type of antibiotic treatment)

E______:

Initial broad antimicrobial spectrum before identification of the organisms directed against the organisms know to cause the infection in question based on patient’s presentation

Empiric

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(Type of antibiotic treatment)

Def_______:

Antimicrobials selected based on clear identification of the organism(s) and proven sensitivity of the organism(s)

Definitive

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(Type of antibiotic treatment)

Proph_______:

Antimicrobial directed against a single pathogen or multiple pathogens to prevent an infection from occurring. Usually short-term (before surgery, dental procedures) but can be long-term (AIDS).

Prophylactic:

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Please be very familiar with the respiratory infections that were emphasized in the threads, readings and study guide [CAP, Aspiration pneumonia, AOM, and ABRS] as well as familiarity with symptom management (Table72-6).

Things to consider are causative organism, risk factors for infection, risk factors for MDR, treatment, consideration of the “whole” patient when selecting among the possible alternative possibilities, drug interactions, adverse effects and patient education

Just a reminder. Start digging into these things soon.

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Most pneumonia arises following the a_________ of microorganisms from the oral cavity or nasopharynx. The term aspiration pneumonia should be reserved for pneumonitis resulting from the altered clearances. The pathogens that commonly produce pneumonia, such as Streptococcus pneumoniae, Haemophilus influenzae, gram-negative bacilli, and Staphylococcus aureus, are relatively virulent bacteria so that only a small inoculum is required and the a_________ is usually subtle. A true a_________ pneumonia, by convention, usually refers to an infection caused by less virulent bacteria, primarily anaerobes, which are common constituents of the normal flora in a susceptible host prone to aspiration [Am J Med. 2013 Nov;126(11):995-1001]

aspiration

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Use of medications such as H2-receptor antagonists or proton-pump inhibitors may alter gastric pH allowing growth of potentially pathogenic organisms within gastric aspirations such that if aspiration occurs, it will more than likely be infectious in nature.

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A number of interventions (eg, positioning, dietary changes, drugs, oral hygiene, tube feeding) have been proposed to prevent aspiration, especially in older adult patients and stroke patients

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Treatment For community acquired aspiration pneumonia consider treatment for both streptococci and anaerobes options include (dosing for adults with normal renal function) - clindamycin 300 mg orally 4 times daily or 600 mg IV every 8 hours - a beta-lactam/beta-lactamase inhibitor such as amoxicillin-clavulanate 875 mg orally twice daily or ampicillin-sulbactam 1.5-3 g IV every 6 hours

For hospital-acquired aspiration pneumonia treatment should be based on suspected pathogens options, with anaerobic coverage, include (dosing for adults with normal renal function) - piperacillin-tazobactam 4.5 g every 6 hours or ampicillin-sulbactam 1.5 g (1 g ampicillin/0.5 g sulbactam) to 3 g (2 g ampicillin/1 g sulbactam) every 6 hours - an antipseudomonal carbapenem, such as meropenem 1 g every 8 hours - an antipseudomonal cephalosporin, such as cefepime 1-2 g every 8-12 hours or ceftazidime 1 g every 8-12 hours PLUS metronidazole 500 mg IV every 8 hours or clindamycin 600 mg-2.7 g IV daily (in 2-4 equally divided doses) - PLUS consideration of vancomycin 15 mg/kg every 12 hours (adjusted to troughs of 15-20 mcg/mL) or linezolid if MRSA is suspect

HAP/VAP/HCAP Hospital-acquired (or nosocomial) pneumonia (HAP) is pneumonia that occurs 48 hours or more after admission and did not appear to be incubating at the time of admission.

Ventilator-associated pneumonia (VAP) is a type of HAP that develops more than 48 to 72 hours after endotrachael intubation.

Healthcare-associated pneumonia (HCAP) is defined as pneumonia that occurs in a non hospitalized patient with extensive healthcare contact, as defined by one or more of the following: - Intravenous therapy, wound care, or intravenous chemotherapy within the prior 30 days - Residence in a nursing home or other long-term care facility - Hospitalization in an acute care hospital for two or more days within the prior 90 days - Attendance at a hospital or hemodialysis clinic within the prior 30 days

Multi-drug resistance (MDR) becomes important concern: In critically ill patients, in those receiving antibiotics prior to the onset of pneumonia and in institutions where these pathogens are frequent .. coverage of methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, and antibiotic-resistant gram-negative bacilli such as Acinetobacter spp and Legionella should be considered.

Treatment of HCAP: Early onset ≤ 5 days - S pneumonia, H influenzae MSSA, Gm- bacilli: 3rd generation cephalosporin, respiratory quinolone, amp/sulb OR ertapenem - Late onset or risk of MDR organisms - P aeruginosa, ESBL k pneumonia, Acinobacter spp and MRSA: 4th gen cephalosporin, carbapenem,blactam/blactam inhibitor, respiratory quinolones +/- AMGs. - Table 71-4 - If MRSA is concern- add vanco or linezolid to above

CAP (community acquired pneumonia) - An acute infection of the pulmonary parenchyma in a patient who has acquired the infection in the community - The predominant pathogen is Streptococcus pneumoniae (See Key Concept pp1091). Other common pathogens include Haemophilus influenzae, Moraxella catarrhalis, the atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella spp) and respiratory viruses.

Antibiotic therapy is typically begun on an empiric basis, since the causative organism is not identified in an appreciable proportion of patients. NOTE SITUATIONS WHERE DOUBLE COVERAGE (+) IS WARRANTED Adult outpatient w/ comorbidities OR AB use in past 3 months - respiratory quinolone (eg. levofloxacin, moxifloxacin) OR high dose amoxicillin or amox.tr-clv PLUS macrolide (eg azithromycin, clarithromycin) OR high dose amoxicillin or amox.tr-clv PLUS doxycycline Comorbidities of concern: - Alcoholism: Strep. pneumoniae, H. influenzae - COPD: H. influenzae, M. catarrhalis, Strep. pneumoniae - Post CVA-aspiration: Oral flora, Strep. pneumoniae - Post-obstruction of bronchi: Strep. pneumoniae, anaerobes - Post-influenza: Strep. pneumoniae, Staph. aureus - Neutropenia, immunocompromised host: Pseudomonas aeruginosa - Injection drug use: Staph. aureus (MRSA and MSSA)

Adult inpatient (not ICU)- respiratory quinolone (eg. levofloxacin, moxifloxacin) OR 3rd gen cephalosporin or ertapenem PLUS macrolide or doxy.

Adult inpatient (ICU, no pseudomonas) - 3rd gen cephalosporin PLUS azithromycin or respiratory quinolone

Adult inpatient (ICU, pseudomonas) - cefepime or ceftazidime, or piperac/tazob, or imipenem, or meropenem + quinolone or AMG. If AMG add azithromycin or quinolone.

If CA-MRSA is a concern: add vanco or linezolid or (if susceptible) clindamycin to above.

Vaccinations CDC recommendations on pneumococcal vaccination13-valent pneumococcal conjugate vaccine (PCV13) recommended for: - all children aged 2-59 months - persons aged > 5 years with medical conditions associated with increased risk of pneumococcal disease or complications - recommended dosing schedule varies with patient age and immune status

Vaccinations 23-valent pneumococcal vaccine (Pneumovax, PPSV23) recommended for - all persons aged ≥ 65 years - persons aged 19-64 years with chronic illness, asplenia, immunocompromised, or persons who smoke - children ≥ 2 years old with underlying medical conditions (administration varies with previous vaccination status and medical status)

Vaccinations CDC recommends annual influenza vaccination for everyone 6 months and older with any licensed, age-appropriate flu vaccine (IIV, RIV4, or LAIV4) with no preference expressed for any one vaccine over another.

URI For most people colds are viral and symptoms are self-limited Options: Table 72-6 - - OTCs?? (analgesics/antipyretics, saline nasal irrigation, nasal glucocorticoids, oral/ nasal decongestants, mucolytic, antihistamines, etc - Precautions? - Limitations?

AOM (Acute Otitis Media) Presence of middle ear fluid and inflammation of the mucosa that lines the middle ear space - S. pneumoniae is the most important bacterial cause of AOM, but can include others such as H influenza, M catarrhalis - Risk factors - Table 72-1

It is important to make an accurate diagnosis of AOM to avoid the inappropriate use of antibiotics and the associated increase in antibiotic-resistance rates.

The choice of strategy for treating AOM depends upon the age of the child, the severity of illness, and parental preference - If observation option is used, mechanism must be in place to ensure follow-up and begin antibiotic therapy if child worsens or fails to improve within 48-72 hours of onset of symptoms - When decision to treat AOM with antibiotics has been made, reassess patient if caregiver reports symptoms have worsened or failed to respond to initial antibiotic therapy within 48-72 hours

Amo________ is the drug of choice in most patients for AOM (Acute Otitis Media).

Amoxicillin

Treatment for AOM (Acute Otitis Media): High dose amoxicillin - amoxicillin recommended if child has not received amoxicillin in past 30 days, does not have concurrent purulent conjunctivitis, and is not allergic to penicillin.

Treatment for AOM (Acute Otitis Media): Amox/tr-clv - antibiotic with additional beta-lactamase coverage (amoxicillin-clavulanate) is recommended if child has received amoxicillin in past 30 days, has concurrent purulent conjunctivitis, or has history of recurrent AOM unresponsive to amoxicillin.

Treatment for AOM (Acute Otitis Media): Cefuroxime, cefpodoxime or cefdinir (14mg/kg/d child) - Reasonable with Mild hypersensitivity reactions. - Mild delayed hypersensitivity reactions (Type II, II, Iv) to penicillin appear after more than one dose, typically after days of treatment. They lack features of immunoglobulin E (IgE)-mediated reaction (e.g., anaphylaxis, angioedema, bronchospasm, urticaria) and serious/life-threatening delayed drug reactions.

Treatment for AOM (Acute Otitis Media): ALT - macrolide, clindamycin OR smz/tmp - Reasonable alternatives with anaphylaxis or IgE mediated reaction to penicillin / cephalosporin - Immediate reactions (Type I) to penicillin classically begin within one hour of the initial or last-administered dose and have features of IgE-mediated reaction (e.g., anaphylaxis, angioedema, bronchospasm, urticaria) or Serious delayed reactions.

Treatment for AOM (Acute Otitis Media): Adjunctive therapies / Pain management - - Pain is a common feature of AOM and may be severe. Treatment to reduce ear pain in children with AOM whether or not they are treated with antibiotics is recommended - oral analgesics such as acetaminophen or ibuprofen - topical anesthetics - Most, if not all have been withdrawn from the market in the United States because they have not been evaluated by the US Food and Drug Administration for safety, effectiveness, and quality - Decongestants and antihistamines - Studies suggest lack of benefit and a potential for delayed resolution of middle ear fluid - external application of heat or cold, instillation of olive oil or herbal extracts - clinical conclusions regarding use is limited due to lack of supporting evidence

AOM (URI) Caused by: H influenzae, s pneumoniae, m catarrhalis. Treated with: - High dose amoxicillin (90mg/kg/d child)[i] --- - Amox/tr-clv if coverage for  lactamase producing bacteria is necessary [ii] - Cefuroxime, cefpodoxime or cefdinir(14mg/kg/d) - ALT - macrolide, clindamycin or smz/tmp[iii]

Sinusitis - Acute rhinosinusitis (ARS) is defined as symptomatic inflammation of the nasal cavity and paranasal sinuses lasting less than four weeks. The term "rhinosinusitis" is preferred to "sinusitis" since inflammation of the sinuses rarely occurs without concurrent inflammation of the nasal mucosa - Risk factors for ARBS - table72-3

In addition to supportive care, options for the outpatient management of uncomplicated acute bacterial rhinosinusitis (ABRS) are observation or antibiotics depending on patient follow-up.

ABRS (acute bacterial rhinosinusitis) may be a self-limited disease and patients may improve without antibiotic therapy.

acute bacterial rhinosinusitis (ABRS) Pathogens: - H influenzae, s pneumoniae, m catarrhalis - Other less frequent causes

Macrolides, smz-tmp, and second- or third-generation cephalosporins are not recommended for empiric therapy because of high rates of resistance of S. pneumoniae (and of H. influenzae for trimethoprim-sulfamethoxazole) Note that the alternative in a child does not include doxycycline.

- Preferred, no risk of resistance[i] or children mild/mod Dx[ii]- Std dose amox +/- tr-clv - Preferred, risk of resistance[iii]or children severe Dx[iv] - High dose amox +/- tr-clv - Alt Adult - respiratory quinolone, doxy, OR clindamycin ( + )cefixime or cefpodoxime - Alt Child - cefpodoxime ,cefdinir, levofloxacin[v]

Pharyngitis - Clinical features of GAS (group A streptococcus) include the sudden onset of sore throat, tonsillar exudate, tender cervical adenitis, and fever. Cough and significant rhinorrhea are usually absent. - The most important treatable agent is group A streptococcus (GAS) - For adults at higher risk for severe infections (eg, poorly-controlled diabetes mellitus, immunocompromised, on chronic corticosteroids), throat culture can be obtained at the initial visit even if the rapid antigen detection test is negative for GAS.

Streptococcal pharyngitis (URI) Caused by: Group a streptococcus S pyogenes Treated by: - Pen V (or amox in children) - 1st generation cephalosporin (if allergic to PCN, but not type I) - Azithromycin or clindamycin (if allergic to PCN, type I)

Common Cold Often viral and self limiting with use of antibiotics.

Amoxicillin Coverage: - Gm+ - - Streptococcus - - non beta-lactamase producing Staphylococcus aureus, Listeria, Enterococcus - Fair Gm- - - Shigella (ampicillin), E. Coli, H. flu (non beta-lactamase), proteus mirabilis, N. gonorrhea, Pasteurella multocida -Rash, diarrhea - DIs: ¬ [MTX] , OCs??

beta lactam / beta lactamase inhibitor - Coverage - against b lactamase producing bugs and B. fragilis, Haemophilus influenza, Proteus, Klebsiella, E. Coli, Moraxella catarrhalis, N. gonnorrhea. Staphylococcus aureus - Bacteroides frag. (anaerobic)

Clindamycin Coverage - Gm+ Streptococcus sp, Staphylococcus sp (MSSA only), acnes , Anaerobes, Atypicals - Rash, Diarrhea , Pseudomembranous colitis, ↑ AST/ALT; thrombocytopenia granulocytopenia - [US Boxed Warning]: Can cause severe and possibly fatal colitis. Should be reserved for serious infections where less toxic antimicrobial agents are inappropriate. It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections. Hypertoxin-producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. C. difficile-associated diarrhea (CDAD) must be considered in all patients who present with diarrhea following antibiotic use. CDAD has been observed >2 months postantibiotic treatment. - If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Institute appropriate fluid and electrolyte management, protein supplementation and surgical evaluation as clinically indicated. - Antibiotic treatment of C. difficile

* Tetracyclines (including doxycycline) Coverage: Wide range of Gm + (CA-MRSA) and Gm - coverage with high degree of resistance, Anaerobic coverage, Atypical coverage -Side Effects: GI, Photosensitivity, Tooth discoloration (peds), Dizziness DIs: related mostly to binding (chelation) with multi-valent cations Separate administration (2 hours before or after)

Quinolones - Coverage: Available agents have varying degrees of Gm +, Gm - and anaerobic coverage depending on the generation Side Effects: GI, Rash, Photosensitivity, QT prolongation (levo / gemi / moxi-floxacin), Arthropathy, Tendon rupture (peds / elderly) DIs: Chelation with multi-valent cations , ¬alter [theophylline, digoxin], + warfarin =Increased bleeding

Macrolides - can be thought of as alternative to PCNs. Coverage: - Gm + coverage : S. pneumoniae; S. pyogenes; staphylococci (S. aureus) [NOT MRSA], Clostridium perfringens - Gm - coverage: generally poor - some H. influenzae - some misc. coverage: mycoplasma, legionella, chlamydia Side Effects: GI, Cholestasis, QT prolongation

sulfonamides - Gm+ streptococci, staphylococci – including MRSA, CA-MRSA); Gm - E. coli, Haemophilus, Klebsiella, Proteus, Shigella - Others - Nocardia, Chlamydia trachomatis, Pneumocystis carinii Side Effects: Rash, Fever, n/v, Diarrhea , Hemolytic disturbances, Crystalluria, Bone marrow suppression - Caution in late pregnancy and newborns

Antimicrobial agents that may induce C.diff diarrhea and colitis: Frequently Associated: - Fluroquinolones - Clindamycin - Cephalosporins (broad spectrum) - Penicillins (broad spectrum)

Antimicrobial agents that may induce C.diff diarrhea and colitis: Occasionally Associated: - Macrolides - Trimethoprim-sulfamethoxazole

Antimicrobial agents that may induce C.diff diarrhea and colitis: Rarely Associated: - Aminoglycosides - Tetracyclines - Metronidazole - Vancomycin

Resistance: The capacity of a species or strain of microorganism to survive exposure to a toxic agent (as a drug) formerly effective against it due to genetic mutation and selection for and accumulation of genes conferring protection from the agent especially as a result of overuse of the agent which selectively destroys individual microorganisms lacking the protective genes.

Susceptibility: Lack of ability to resist some extraneous agent (such as a pathogen or drug).

Pathogenicity: Causing disease.

Virulence: Severity of disease.

MIC (minimum inhibitory concentration): lowest concentration of a chemical that prevents visible growth of a bacterium.

Empiric therapy: prescribing medication before identifying cause.

Definitive therapy: treating the cause; best choice for treatment.

De-escalation: decrease of dose.

Preventative strategies for LRTIs: - vaccination against influenza, pneumonia, and Covid - smoking cessation

Risk factors for LRTIs: Risk factors for multidrug-resistant (MDR) bacteria. These factors include: - IV ABT use within the past 90 days - septic shock at the time of HAP or VAP - ARDs preceding VAP - five or more days of hospitalization - acute renal replacement therapy

Risk factors for aspiration include dysphagia, change in oropharyngeal colonization, GER, and decreased host defenses.

Risk factors for LRTIs: - COPD patients and those with cystic fibrosis

Can't treat an infection if you don't know what is causing it.

Common pathogens for community pneumonia: Aerobic bacteria: - S. pneumoniae - H. influenzae - M. catarrhalis Atypical: - M. pneumoniae - C. pneumoniae - L. pneumophila Viruses: rhinoviruses and influenza most common, coronaviruses may be increasing in prevalence

Common pathogens for aspiration pneumonia: Oral contents: - anaerobes - V. streptococci GI contents with pH increase enteric gram-negative bacilli

Common pathogens for hospital pneumonia: S. pneumoniae, MSSA, Escherichia coli, Klebsiella pneumoniae (M. pneumoniae, C. pneumoniae are rare) (MDR pathogen risk factors present; MRSA, Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing Gram-negative bacilli, carbapenemase-producing Gram-negative bacilli)

Common pathogens for ventilator pneumonia: MRSA, extended-spectrum β-lactamase-producing Gram-negative bacilli, P. aeruginosa, Acinetobacter spp., carbapenemase-producing Gram-negative bacilli

Treatment (adults only, non-ICU) based on patient specific characteristics such as co-morbidities (eg diabetes, COPD), allergies (eg, PCN, macrolides, sulfa), drug interactions (quinolones + antacids/dairy, macrolides inhibit P450), CIs (tetracyclines in children), ADRs (clindamycin causing C. diff, quinolones causing tendon rupture and QT prolongation, tetracyclines causing photosensitivity), etc.

True ABT allergy: hives and cannot breathe.

Tetracyclines turn the inside and outside of teeth yellow in people under age 18.

Clindamycin is the most common cause of C. diff. The worst offender.

Put on sunscreen when taking tetracyclines due to photosensitivity.

Adult outpatient otherwise healthy Empirical coverage against Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, (Mycoplasma pneumoniae, Chlamydophila pneumoniae much less common) Monotherapy Amoxicillin 1 g three times daily, or doxycycline 100 mg twice daily (or azithromycin 500 mg × 1 then 250 mg once daily, clarithromycin 500 mg twice daily or clarithromycin ER 1000 mg once daily, only if local pneumococcal resistance rates are < 25%)

Adult outpatient comorbidities Empirical coverage against S. pneumoniae, H. influenzae, S. aureus, (M. pneumoniae, C. pneumoniae much less common) Combination therapy Amoxicillin-clavulanate 500/125 mg three times daily or 875/125 mg twice daily or 2000/125 mg twice daily or cefpodoxime 200 mg twice daily, or cefuroxime 500 mg twice daily, plus azithromycin, or clarithromycin or, doxycycline (see dosing above) Monotherapy Gemifloxacin 320 mg once daily, levofloxacin 750 mg once daily, moxifloxacin 400 mg once daily

1 person = monotherapy 1 person with multiple problems = combination therapy.

Preventative strategies for ABRS (Acute Bacterial Rhinosinusitis): Bacteria that cause sinusitis are similar to those in AOM (acute otitis media). S. pneumoniae and H. influenzae cause more than half of ABRS cases, with an additional 8% to 16% of cases caused by M catarrhalis. Similar to AOM, an increased prevalence of H. influenzae has been reported in ABRS, and certain factors predict the presence of drug-resistant pathogens.

Preventative strategies for AOM (Acute Otitis Media): AOM: Influenza vaccines and pneumococcal conjugate vaccines may prevent AOM in certain patients, but their benefits are small and they should not be administered solely for this purpose. Antibiotic prophylaxis is not recommended because of selection pressure on microbial resistance. Exclusive breast-feeding for the first six months of life and avoidance of tobacco smoke are advised, but the effects of these interventions remain unproven.

Risk factors for otitis media: Atopy craniofacial defects, daycare attendance (cesspool), GER, immunodeficiency, lack of breastfeeding, male sex, non-Hispanic white race, pacifier use, positive family history/genetic predisposition, siblings, tobacco smoke exposure, viral respiratory tract infection, winter season, young age at first diagnosis.

Risk factors for ABRS (acute bacterial rhinosinusitis): Allergic or nonallergic rhinitis, anatomic defects (eg., septal deviation), aspirin allergy, nasal polyps, asthma, cystic fibrosis, ciliary dyskinesia, dental infections or procedures, immunodeficiency, intranasal medications or illicit drugs (cocaine), mechanical ventilation, nasogastric tubes, swimming or diving, tobacco smoke exposure, trauma or barotrauma, viral respiratory tract infection, winter season.

Colds: Many viruses cause the common cold, including rhinoviruses (most common), coronaviruses, parainfluenza viruses, respiratory syncytial virus, and adenovirus.

Pharyngitis: a common manifestation of viral URIs. Streptococcus pyogenes (Group A streptococci) is the most common bacterial cause, responsible for 20% to 30% of cases in children and 5%-15% of adult infections.

Rhinosinusitis: affects 12% of adults annually in the United States. It is caused mainly by respiratory viruses but can also be triggered by allergies or environmental irritants. Viral rhinosinusitis is complicated by secondary bacterial infection in 0.2% to 2% of adults and 5-7% of children.

ABRS: Bacteria that cause sinusitis are similar to those in AOM. S. pneu and H. infl cause more than half of ABRS cases, with an additional 8-16% of cases caused by M. cata.

AOM: Although AOM occurs frequently with viral URIs, bacteria are isolated from middle ear fluid in 70-90% of children with AOM. Historically, S. pneu was the most common organism, responsible for up to half of bacterial cases, respectively. Routine childhood pneumococcal vaccination has altered the microbiology such that H. infl is now responsible for up to 60% of bacterial cases. Viruses are isolated from middle ear fluid with or without concomitant bacteria in up to 70% of cases. Lack of improvement with ABTs is usually a result of viral infection and subsequent inflammation rather than ABT resistance.

Treatment algorithm for uncomplicated AOM in children 6 months to 12 years of age. Receipt of amoxicillin in past 30 days, concurrent purulent conjunctivitis, or history of recurrent AOM unresponsive to amoxicillin? - If no (and not allergic to penicillins), use amoxicillin - if yes, (and not allergic to penicillins), use amoxicillin-clavulanate - if yes/no AND allergic to penicillins: Do they get anaphylaxis or other severe IgE mediated responses? - if not, use cefdinir, cefuroxime, cefpodoxime, or ceftriaxone - if so, consider cephalosporins; alternatives are macrolides or clindamycin.

study this thoroughly.

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Amoxicillin Lacks coverage against β-lactamase producers

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Amoxicillin– clavulanate Broad coverage particularly with high doses; Augmentin XR (2 g every 12 hours) targeted toward PRSP (penicillin-resistant streptococcus pneumoniae).

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Cefdinir Preferred oral liquid cephalosporin owing to good palatability

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Cefixime IDSA recommends use only in combination with clindamycin

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Cefpodoxime proxetil IDSA recommends use only in combination with clindamycin

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Cefuroxime axetil Only included as an option in AAP guideline; suspension no longer available in the United States

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Ceftriaxone Experts recommend a 5-day treatment course; useful for patients who are vomiting and cannot tolerate oral therapy

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Doxycycline Can cause photosensitivity and GI effects (abdominal pain, esophagitis, or esophageal ulcers); tooth staining in children younger than 8 years is unlikely with durations of therapy that are 21 days or less; many drug–drug interactions (antacids, iron, calcium)

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Levofloxacin Common fluoroquinolone side effects are nausea, vaginitis, diarrhea, dizziness, photosensitivity; many drug–drug interactions (antacids, iron, calcium); serious side effects (tendon rupture, muscle or joint pain, confusion, hallucinations, neuropathies, hypoglycemia, QT prolongation, aortic ruptures or tears) limit their broad utility for ABRS

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Moxifloxacin Common fluoroquinolone side effects are nausea, vaginitis, diarrhea, dizziness, photosensitivity; many drug–drug interactions (antacids, iron, calcium); serious side effects (tendon rupture, muscle or joint pain, confusion, hallucinations, neuropathies, hypoglycemia, QT prolongation, aortic ruptures or tears) limit their broad utility for ABRS

Antibiotics for the Treatment of Acute Bacterial Rhinosinusitis (Comments Section) Table 75-4: Clindamycin No Gram-negative coverage; use only in combination with cephalosporin

Antibiotics for the Treatment of Acute Otitis Media (Comments) Table 75-2): Amoxicillin Drug of choice for AOM; experts recommend high dose to overcome penicillin resistance

Antibiotics for the Treatment of Acute Otitis Media (Comments) Table 75-2): Amoxicillin– clavulanate More diarrhea than amoxicillin; amoxicillin:clavulanate ratio of 14:1 preferred because of lower daily clavulanate component

Antibiotics for the Treatment of Acute Otitis Media (Comments) Table 75-2): Cefdinir Preferred oral cephalosporin (pleasant taste); separate from Fe supplements by 3 hours

Antibiotics for the Treatment of Acute Otitis Media (Comments) Table 75-2): Cefpodoxime proxetil Suspension is bitter tasting

Antibiotics for the Treatment of Acute Otitis Media (Comments) Table 75-2): Ceftriaxone 3-day regimen preferred for PRSP

Antibiotics for the Treatment of Acute Otitis Media (Comments) Table 75-2): Cefuroxime axetil Suspension is no longer available in the United States

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Acetaminophen (Analgesics/Antipyretics) Use with caution in preexisting liver disease; monitor acetaminophen dose from all sources (prescription, nonprescription, and combination products); some experts recommend a maximum dose of 3 g/day in adults

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Ibuprofen (Analgesics/Antipyretics) Use with caution in cardiovascular disease and those with history of peptic ulcer disease or GI bleeding; avoid use in elderly, renal impairment, and heart failure; avoid in third trimester of pregnancy

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Oxymetazoline 0.05%c (Intranasal Decongestant) Limit use of intranasal decongestants to 3–5 days to minimize risk of rebound congestion; use with caution in patients with cardiovascular disease, diabetes, hyperthyroidism, or prostatic hypertrophy

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Phenylephrine 0.25%, 0.5%, 1% (Intranasal Decongestant) Limit use of intranasal decongestants to 3–5 days to minimize risk of rebound congestion; use with caution in patients with cardiovascular disease, diabetes, hyperthyroidism, or prostatic hypertrophy

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Pseudoephedrine (Systemic Decongestant) Avoid use in patients with cardiovascular disease; children and elderly have increased risk of adverse effects (cardiovascular or CNS stimulation); use with caution in patients with diabetes, hyperthyroidism, prostatic hypertrophy; avoid in first trimester of pregnancy

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Phenylephrine (Systemic Decongestant) Avoid use in patients with cardiovascular disease; children and elderly have increased risk of adverse effects (cardiovascular or CNS stimulation); use with caution in patients with diabetes, hyperthyroidism, prostatic hypertrophy; avoid in first trimester of pregnancy

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Dextromethorphan (Cough Suppressant) Increased adverse effects in children and poor metabolizers (5%–10% of Caucasians; 2% in African Americans and Asians); can cause dysphoria and serotonin syndrome; use caution in those taking psychotropic medication.

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Guaifenesin (Expectorant) May cause nausea and abdominal pain, particularly in high doses.

Select Nonprescription Medications for the Common Cold for Patients 6 Years of Age and Older (Comments) 75-6: Intranasal ipratropium 0.06%c (Anticholinergic) Used for rhinorrhea only; does not improve congestion, postnasal drip, or sneezing; can cause epistaxis and nose/ mouth dryness

Elderly can only take 3 grams in 24 hours of APAP. Younger folks can take 4 grams. If they have impaired liver function, then max of 3 grams in 24 hours. KNOW for exam.

Most URIs are caused by viruses, have nonspecific symptoms, and resolve spontaneously.

Treatment for AOM: Amoxicillin is the drug of choice in most patients because of its proven effectiveness, high middle ear concentrations, excellent safety profile, low cost, palatable suspension, and relatively narrow spectrum.

S. pne_______ is the most important bacterial cause of AOM, but can include others such as H influenza, M catarrhalis

S. pneumoniae

Only use cefixime in combination with clin______n for ABRS.

clindamycin

Module 7: Antimicrobial Selection & Respiratory Infections Flashcards

(138 cards)