Drugs for Common Bacterial Infections

Respiratory Tract

100

Most cases of acute pharyngitis are caused by this class of pathogens?

What are viruses -Influenza -EBV -Rhinovirus No indication for antibiotics

200

Five to fifteen percent of adult cases of acute pharyngitis are caused by this pathogen?

What is Group A Streptococcus Additional bacterial pathogens: -Group C Streptococcus -Group G Streptococcus -Fusobacterium necrophorum -Neisseria gonorrhea

300

Name the preferred antibiotic and duration of treatment for Group A Streptococcal infection?

-Penicillin -Treatment duration 10 days Bonus: treatment options for those with a severe penicillin allergy include? Common drugs to avoid due to unacceptable levels of resistance?

400

An initial approach to acute sinusitis should involve the following?

Cases often viral and the following can be used: -Analgesics -Nasal steroid -Nasal saline irrigation

500

Name the top three causative bacterial pathogens for acute sinusitis?

What are: -Streptococcus pneumoniae -Haemophilus influenzae -Moraxella catarrhalis Bonus: what can you counsel patients regarding the usual course of untreated acute bacterial sinusitis? Under what circumstances would you consider treatment and with what antibiotic?

Urinary Tract

100

Most episodes of acute uncomplicated cystitis are caused by this bacterial pathogen?

What is: E. coli. Bonus: name three additional common pathogens

200

Name three first line antibiotic regiments for acute uncomplicated cystitis?

What are: -TMX/sulfamethoxazole -Nitrofurantoin monohydrate -Fosfomycin tromethamie Bonus: outline recommended treatment duration for each drug for uncomplicated UTI.

300

What level of local resistance to urinary pathogens (E. coli and others) is generally considered unacceptable

What is 20% Discuss antibiogram use at Essentia East

400

What concern would you consider before prescribing Nitrofurantoin for an elder patient?

What is renal function namely CrCl -Contraindicated in patients with a CrCl ≤60 mL/min according to the manufacturer. Short-term use for cystitis in patients with a CrCl ≥30 mL/min is probably safe. - a primary reason that nitrofurantoin is on the Beers List of medications to avoid in the elderly is inadequate drug concentration in the urine when creatinine clearance falls below 60 mL/min.

500

TMP/SMX is commonly recommended as the preferred drug for UTI in elders. Name three side effects or dosing concerns associated with the use of TMP/SMX in older patients

What are: -TMP-SMX dosing should be altered for patients with renal insufficiency whose creatinine clearance is less than or equal to 30 mL per minute. It is generally recommended to provide 50 percent of the dose for patients with a creatinine clearance between 15 and 30 mL per minute. -Another potentially life-threatening side effect includes hyperkalemia due to blockade of the collecting tubule sodium channel by trimethoprim (an action similar to that induced by the potassium-sparing diuretic amiloride) -Rash and pruritus (SJ syndrome is a risk as well) -Hemolysis in patients who have glucose-6-phosphate dehydrogenase deficiency

Skin & Soft Tissue/Respiratory Contd

100

What is the evidence to support antibiotic use after incision and drainage of small abscesses typically caused by Staph aureus?

-Addition of oral trimethoprim/sulfamethoxazole, clindamycin, or doxycycline can improve abscess cure rates. -Linezolid is an alternative for oral treatment. -Fluoroquinolones (except possibly delafloxacin) should not be used empirically to treat skin and soft tissue infections. -NEJM 2017; 376:2545. -Go to side effects for 200-

200

What is the general difference in resistance patterns between community acquired MRSA and healthcare-associated strains?

-Unlike healthcare-associated strains, which are often resistant, CA-MRSA strains have generally been susceptible to trimethoprim/sulfamethoxazole, tetracyclines, and clindamycin (local clindamycin resistance rates vary). -Both types of MRSA strains are susceptible in vitro to vancomycin, daptomycin, and linezolid. -Resistance to fluoroquinolones is common and is increasing in both healthcare and community settings

300

What two classes of antibiotics would you want to avoid if you made the decision to treat acute bacterial sinusitis?

What are: -Macrolides (namely azithromycin) -TMP/SMX -Not recommended due to increasing resistance among pneumococci (Strep pneumonia)

400

Under what clinical circumstances would you consider treating a patient with an acute exacerbation of chronic bronchitis?

-Acute exacerbations of chronic bronchitis (AECB) are also often viral in origin, but moderate to severe exacerbations in patients with COPD are usually treated with antibacterial drugs. -Like sinusitis, bacterial AECB are often caused by S. pneumoniae, H. influenzae, or M. catarrhalis and treated with amoxicillin/clavulanate. -Doxycycline can be considered for adults who are allergic to penicillin. -Because of the risk of serious adverse effects, fluoroquinolones should be reserved for patients who lack other treatment options

500

Detail the difference between Type 1 and Type 2 necrotizing fasciitis and potential differences in treatment

-Group A Streptococcus, S. aureus, or Clostridium spp., with or without other anaerobes, can cause fulminant soft tissue infections and necrosis, particularly in patients with diabetes. -Type 1 is polymicrobial; more associated with DM2 -Type 2 is usually monomicrobial with GAS or other beta hemolytic Strep species -If such infections are suspected, rapid treatment with clindamycin plus a penicillin is recommended. -In severely ill patients, vancomycin, linezolid, or daptomycin should be added until MRSA is ruled out. -Surgical debridement is essential to the management of necrotizing skin and soft tissue infections and should not be delayed while awaiting blood cultures or skin aspirates.

Side Effects/Miscellany

100

Monday morning you are managing warfarin in your active octogenarian after urgent care placed her on warfarin Friday evening. What changes in her INR and dosing should you expect?

I found this answer on a school of pharmacy website -There is really no more "classic" drug-drug interaction than Bactrim and Warfarin. It just hits on so many levels. They go together like Chinese food and chocolate pudding. Like skateboarding and freeway ramps. Bactrim inhibits CYP 2C9; which you remember is responsible for breaking down the more potent S-isomer of warfarin. Bactrim also inhibits CYP 3A4; which you remember is responsible for breaking down the less potent R-isomer of warfarin. Bactrim can also (somewhat) disrupt the normal flora in the gut; which you remember is responsible for breaking down and getting vitamin K into your body. Finally, Bactrim is very highly protein bound and can displace warfarin from the albumin it's bound to in your patient's blood -Consider reducing the dose by 50% or even holding a dose.

200

Fluoroquinolones (especially ciprofloxacin) have been the most common class of antibiotics prescribed for urinary tract infections. Why, according to the FDA, should they no longer be used for empiric treatment unless no other treatment options exist?

In 2016, the FDA required changes in the labeling of systemic fluoroquinolones to warn that their risk of serious adverse effects, including tendinitis and tendon rupture, peripheral neuropathy and CNS effects, generally outweighs their benefits for treatment of uncomplicated infections such as acute cystitis.

300

Name two age related changes that influence our choice of agent and dosing in elders

-An increased volume of distribution may result from the proportional increase in body fat relative to skeletal muscle with aging. -Decreased drug clearance may result from the natural decline in renal function with age, even in the absence of renal disease. -Larger drug storage reservoirs (body fat) and decreased clearance prolong drug half-lives and lead to increased plasma drug concentrations in older people.

400

CDC reports what percentage of LTC facility residents will antibiotics per year?

What is: -Antibiotics are among the most frequently prescribed medications in nursing homes, with up to 70% of residents in a nursing home receiving one or more courses of systemic antibiotics in a year. -Similar to the findings in acute care hospitals studies have shown that 40%-75% of antibiotics prescribed in nursing homes may be unnecessary or inappropriate. -This high level of exposure to antibiotics can lead to serious adverse events and consequences for the individual and the community, such as Clostridium difficile infections, drug-drug interactions, and colonization or infection with antibiotic-resistant organisms. C diff infection is the most common—and sometimes fatal—cause of antibiotic-related acute diarrhea in nursing homes.[

500

Describe the phenomenon of a prescribing cascade and how that relates to our elder patients at home or in a LTC facility

-Polypharmacy increases the possibility of "prescribing cascades". -A prescribing cascade develops when an ADE (adverse drug event) is misinterpreted as a new medical condition and additional drug therapy is then prescribed to treat this medical condition -In a sample of Medicare beneficiaries discharged from an acute hospitalization to a skilled nursing facility, patients were prescribed an average of 14 medications, including over one-third with side effects that could exacerbate underlying geriatric syndromes

Newer Drugs

100

New fluoroquinolone approved by FDA in June of 2017

-What is delafloxacin -Skin and skin structure infections: Treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by susceptible isolates of Staphylococcus aureus (including MRSA and MSSA isolates) -Same FDA boxed warning as other quinolones

200

Detail the newer 5th generation cephalosporin

What is: ceftaroline -Ceftaroline is a fifth generation cephalosporin whose active metabolite has a spectrum of in vitro activity similar to ceftriaxone but with improved gram-positive activity. In particular, ceftaroline has higher affinity for PBP2a in methicillin-resistant staphylococci, and has activity against MRSA, as well as vancomycin-intermediate Staphylococcus aureus (VISA). -In addition, ceftaroline has activity for Streptococcus pneumoniae that is intermediate or resistant to penicillin or ceftriaxone. -Ceftaroline is not active for enterococci nor against AmpC-overproducing or ESBL-producing Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, or Bacteroides fragilis. -FDA approved for adults 2010 and pediatric patients 2016

300

Why use fosfomycin?

-Current guidelines published by the Infectious Diseases Society of America and the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) recommend fosfomycin, nitrofurantoin, and trimethoprim-sulfamethoxazole (TMP-SMX) as first-line agents to treat acute uncomplicated UTIs in adult females, reserving fluoroquinolones, amoxicillin-clavulanate, and other β-lactams as second-line agents. -Elevated rates of resistance (>10–20%) to TMP-SMX, as well as fluoroquinolones, are now widely reported for uropathogenic isolates of E. coli in Canada and elsewhere. -The most recently published Canadian study, describing antimicrobial resistance rates among E. coli isolated from patients with urinary tract infections, reported on isolates collected from 2010 to 2013 and found susceptibility rates of 74.7% to TMP-SMX, 77.4% to ciprofloxacin, 81.3% to amoxicillin-clavulanate, 96.1% to nitrofurantoin, and 99.4% to fosfomycin.

400

What is the role for aztreonam in our antibiotic pantheon?

What is treatment of gram negative bacilli - Treatment of patients with urinary tract infections, lower respiratory tract infections, septicemia, skin/skin structure infections, intra-abdominal infections, and gynecological infections caused by susceptible gram-negative bacilli -Practically used when a severe beta-lactam allergy is present and gram negative coverage is needed.