These patients almost never need a change in antimicrobial therapy, but need more time—and elevation. I was taught by one of my mentors of the importance of elevating an extremity when treating cellulitis. My clinical experience has borne out this wisdom.
In addition, patients with lower-extremity edema or venous insufficiency or venous stasis who present with cellulitis must have edema and stasis aggressively treated for the cellulitis to respond to antimicrobial therapy. Five years ago in Ohio, if a patient presented with pyelonephritis or a complicated UTI as a community-acquired infection, it was unusual for the causative pathogen to be quinolone resistant. Quinolones such as ciprofloxacin could be used as empiric therapy for serious gram-negative infections with a great deal of confidence that the causative agent would be sensitive.
In the last 5 years we have seen a steady, progressive increase in resistance to quinolones in both community acquired and nosocomial infections 7,8.
Seriously ill patients with infections that are likely due to gram-negative rods should not be treated empirically with quinolone monotherapy in most settings.
Oral quinolones, due to their excellent oral bioavailability, continue to have in important role in treating gram-negative infections, but their use should be based on the results of a culture with antimicrobial susceptibility. Patients who are colonized with VRE in the stool will clear colonization over several weeks or months if there is no antimicrobial pressure to select for VRE. Infectious disease clinicians spend a lot of time trying to allay the fear of patients and families who become extremely nervous due to isolation procedures for VRE.
My usual approach is to tell the patients that the only reason they are in isolation is to prevent VRE from spreading to the very, very small group of patients who actually are susceptible to infection with VRE, such as liver transplant patients. I tell the family there is almost no chance that healthy family members will develop a VRE infection and that the VRE bacteria is normally found as a natural part of the human intestinal flora.
VRE is simply 1 strain that has particular resistance to antibiotics, making it difficult to treat when infection occurs, but it is not more pathogenic. Infection with VRE is relatively rare and with the possible exception of cystitis or bladder colonization there is an extremely low risk of any actual infection despite VRE colonization.
Uncomplicated cystitis due to VRE can usually be treated with nitrofurantoin. In the last 5 years in the United States, there has been a steady increase in MRSA infections in patients without traditional risk factors 9, Historically, clinicians have been concerned about MRSA in nursing home patients, patients in other long-term care facilities, injection drug users, and hospitalized patients.
In the last 5 years there have been increasing numbers of patients with MRSA with none of these risk factors. Often these patients present with a serious life-threatening S. It is now appropriate to give vancomycin empirically for patients who have serious illnesses due to suspected S. As ID practitioners, we do not want to encourage overuse of vancomycin, and clinicians should quickly switch to other agents if the patient proves not to be infected with MRSA.
While vancomycin is a useful drug, it is considered inferior to the beta-lactams for many infections, such as bone or joint infections, and should only be used in patients with documented or suspected MRSA, or patients intolerant of beta-lactams. Several new drugs provide alternatives to vancomycin for MRSA, including linezolid and daptomycin.
Both of these agents are more expensive and have not proven in clinical trials to be superior with the possible exception of linezolid for MRSA pneumonia. Linezolid offers the advantage of having excellent oral availability; however, oral linezolid use is complicated by its high cost. Insurance companies will almost always approve oral linezolid if the only alternative is continued hospitalization, skilled nursing home placement, or home IV antibiotic therapy. So these are 10 things ID physicians wish all hospitalists knew.
The 11th is that we enjoy working with our hospitalist colleagues, so please call when you think you need us. For cefepime and ceftriaxone, beware CNS toxicity of encephalopathy, altered mental status, and seizures in the elderly and those with renal failure.
Ceftazidime and Cefepime sometimes have activity against certain ESBL producing organisms, but reports of failure in this setting so use with caution. Great penetration virtually everywhere, including CSF. Other differences of Ertapenem vs other carbapenems is lack of activity vs Acinetobacter and Enterococci. Main advantages:1 No cross-reactivity with PCN allergy except with Ceftazidime — cross-reactivity due to identical side chain and 2 Does not cause renal failure almost no significant toxicity Beware significant rate of resistance of Pseudomonas in most institutions, so empiric double coverage often required.
No ESBL coverage. Most are bacteriostatic, except for Aminoglycosides generally considered cidal due to irreversible binding and disruption of outer cell membrane 1. Azithromycin is the drug of choice for most atypical infections. Erythromycin now used mostly as GI motility agent — prior to endoscopy, or to advance feeding tubes. Clarithromycin also used for MAC treatment in combination with other drugs. Azithromycin has better H. Side Effects: photosensitivity, GI discomfort, teeth discoloration, inhibits bone growth in children, teratogenic, steatosis and hepatotoxicity.
Doxycycline is the preferred tetracycline in most cases due to convenient BID dosing, and lack of food-drug interactions. Often part of empiric therapy in toxic-appearing patients with fever and rash mainly for Rocky Mountain Spotted Fever.
Doxycycline has excellent bioavailability. Also has activity vs PCP combine with primaquine and toxoplasmosis combine with pyrimethamine Beware increasing resistance among Bacteroides — not a good choice for severe intraabdominal infections. If D-test positive, do not use Clindamycin. Does not penetrate CSF — cannot use for brain abscesses. Traditionally causes highest rate of C. For synergy, best evidence and utility for Enterococcal endocarditis if susceptible.
For Staph prosthetic valve endocarditis, aminoglycoside recommended for 2 weeks with Rifampin. Poor urine and CSF penetration. Aminoglycosides exhibit concentration-dependent killing — more effective with higher peak concentration relative to MIC vs time-dependent killing of beta lactams — more important to maintain levels above MIC Three ways to dose aminoglycosides doses listed for Gentamicin.
Check peak after 3rd dose, trough before 4th dose. Bone marrow suppression — direct, dose-related effect that is reversible. Usually occurs several weeks after drug is stopped. Gray baby syndrome in infants — presents with hypotension, shock, and cyanosis. All fluoroquinolones have excellent bioavailability except Norfloxacin , so use PO whenever possible.
This is false — it is not used in community-acquired PNA due to lack of Strep pneumo coverage. Both Moxifloxacin and Levofloxacin are not typically used for Staph aureus infections due to rapid emergence of resistance. Both Moxifloxacin and Levofloxacin have excellent Pneumococcal activity, but are 2nd-line at best for most other streptococcal infections beta-lactams preferred. Norfloxacin PO — unlike the other Fluoroquinolones, poorly absorbed.
Main use is for spontaneous bacterial peritonitis SBP prophylaxis. Shortage of IV formulation in the U. Dosing varies on indication. The typical 1 g q12 dosing is inadequate for most patients. Check trough prior to 4th dose for severe infections or those with unstable renal function. Some experts will not even check troughs in non-severe, non-MRSA infections in patients with stable renal function. In general, Linezolid is well tolerated for short-term, but not so much long-term.
Since mechanism is static, in general prefer other agents for severe bacteremia, endocarditis. Beware overall increased risk of death when used for severe infections metanalysis — FDA black box warning! Double coverage involves a beta-lactam plus either Fluoroquinolone or Aminoglycoside. Use Aztreonam if PCN-allergic. Avoid double beta-lactam therapy.
May be better tolerated than older literature suggests. Drug of choice for most anaerobes , but with notable lack of activity against Propionibacterium acnes , Actinomyces, and Lactobacillus.
For this reason, should never use as monotherapy against above-the-diaphragm infections like lung abscesses, etc. Side effects: nausea, diarrhea, metallic taste, dose-dependent and possibly cumulative peripheral neuropathy avoid multiple courses for recurrent C. Peripheral neuropathy is usually reversible. Not well tolerated long-term. Tigecycline — excellent anaerobic activity.
Like nitrofurantoin, cannot use for pyelonephritis due to poor kidney tissue penetration. Resistance develops rapidly — not suitable for sustained therapy for severe infections. Minimal side effects and very well tolerated. Actual efficacy is controversial but some evidence to support use for short-term prophylaxis. Long-term efficacy is unclear. Contraindicated in renal failure — decreased excretion into urine leads to systemic accumulation and toxicity.
Also consider vancomycin enemas and surgical consult in those situations. Minimal absorption and thus minimal side effects. Noninferior and likely superior to oral vancomycin for initial treatment of C. Main advantage is reduced rates of relapse, but this benefit not seen so far for NAP-1 strain.
Also has higher cure rate when used in patients with C. Resistance develops rapidly, so two important caveats: 1. Never use as monotherapy. Do not use for Staphylococcal infections until low burden of disease i. Side effects: Orange discoloration of body fluids urine, tears, sweat , hepatotoxicity, rare bone marrow toxicity, rash. Multiple drug interactions potent CYP inducer. Only Fluconazole has adequate urinary penetration. Morbid obesity: use actual body weight.
Higher-dose daptomycin may reduce the likelihood of treatment-emergent resistance, is generally well tolerated, and is not associated with excess toxicities IDSA endocarditis guidelines. Emergence of daptomycin resistance may occur while treating Staph aureus especially if previously treated with vancomycin or large burden of bacteria. Resistance can emerge during therapy, which might be avoided somewhat by co-administration of a beta-lactam daptomycin plus ceftaroline might be ideal.
Urinary vancomycin-resistant enterococcus infection daptomycin secreted in urine, might be 1st line here. Note: Inactivated by surfactant in lung, so cannot be used for pulmonary infection. Monitor creatinine kinase. False elevation of INR lab artifact.
This may be sorted out by repeating INR before an infusion when daptomycin is at trough levels. LFT abnormality Acute eosinophilic pneumonia Peripheral neuropathy Medscape monograph: Daptomycin doxycycline back to contents doxycycline dosing Start with mg loading dose in severe infection otherwise steady-state drug levels won't be reached for a few days. For moderate to severe legionella: mg q12 hours for 72 hours, followed by mg q Mostly eliminated by the liver.
Mechanism: Inhibition of protein synthesis through 30s ribosomal binding blocking aminoacyl-tRNA same as tigecycline. Gram-negatives Some E. Zoonotic organisms Coxiella burnetii, Yersinia pestis, Chlamydia psittaci, Bacillus anthracis, leptospirosis, Pasteurella multocida use Coverage for atypical organisms in patients with pneumonia, especially in the following situations: 1 Patients who are at some risk for community-acquired MRSA pneumonia, but not enough risk to justify addition of linezolid or vancomycin doxycycline has fair activity against community-acquired MRSA, but lacks evidence for efficacy in MRSA pneumonia.
Coverage of almost all tick borne illnesses e. Unfortunately, doxycycline will miss babesiosis, so if your tick-exposed patient has hemolysis then babesiosis may require further investigation and specific treatment. Staph aureus skin and soft tissue infections. Vascular irritant: Can cause phlebitis when given IV.
Pancreatitis reported in a few case reports. Medscape monograph: Doxycycline fluoroquinolones back to contents Fluoroquinolones have little role in a modern ICU for the following reasons : 1 Increasing antibiotic resistance e. Removal of fluoroquinolones from the ICU may help control pathogens such as C. Fluoroquinolones can also cause connective tissue problems involving tendinopathy and possibly aortic aneurysm.
Consequently, the FDA has recommended avoidance of fluoroquinolones when possible in a black box warning. The concept of double-coverage of pseudomonas just isn't supported by evidence more on this here.
If you are going to double-cover for pseudomonas, the only antibiotic that adds substantially to a beta-lactam is an aminoglycoside. Adding a fluoroquinolone to an antipseudomonal beta-lactam is like adding a pistol to a cannon — it just doesn't add much explained further here. Listeria advantages of linezolid over vancomycin Better tissue penetration of lung and brain. No nephrotoxicity. Linezolid suppresses toxin production beneficial in toxic shock syndrome and community-acquired MRSA.
Superior spectrum of activity against enterococci including coverage of vancomycin-resistant enterococci. Vancomycin is cleared by the kidneys, which makes therapeutic levels hard to achieve in patients with augmented renal clearance. In contrast, linezolid is cleared by the liver, making dosing and achievement of therapeutic levels easier.
This is forcing us to target higher vancomycin levels, leading to greater vancomycin nephrotoxicity. Over time this will become a more obvious problem our evidentiary base of studies regarding linezolid vs. MSSA, Streptococcus pneumoniae. Bacteremia : In , the FDA released a warning regarding the use of linezolid for catheter-related bloodstream infections below.
However, linezolid is FDA-approved and potentially front-line therapy for treatment of bacteremia due to vancomycin-resistant enterococcus. Linezolid may be used for definite or suspected infection with vancomycin-resistant enterococci. Skin and soft-tissue infections. Linezolid appears to be more effective than vancomycin. Linezolid has excellent CSF penetration and some limited evidence suggests that it may be used in meningitis.
Ideally, serotonergic medications would be stopped and allowed to wash out prior to initiation of linezolid especially fluoxetine, which has a half-life of several days. Note: protective against Clostridioides difficile.
Alternative regimen: mg IV x1, then mg IV daily x4 days. Legionella pneumonia: mg IV daily for days. Morbid obesity or severe illness: May consider mg IV daily. Clarithromycin mg PO twice daily immediate-release formulation. No dose adjustment in hepatic dysfunction kidneys pick up slack in drug excretion. Penetrates most tissues, but not urine or meninges. Excretion: Mostly excreted in the liver. Mechanism: blocks the protein from exiting the 50S ribosomal unit same mechanism as clindamycin.
Clarithromycin may be superior for gram-positives. Atypical organisms e. Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila, pertussis, Coxiella burnetii. Evidence suggests mortality benefit in severe community-acquired pneumonia, possibly due to anti-inflammatory effects. COPD exacerbation although doxycycline may be preferable for patients recently on azithromycin.
Relatively low rate of Clostridioides difficile, compared to most other antibiotics. Contraindicated in myasthenia gravis. May cause transaminitis; cholestasis azithromycin.
Clarithromycin: May increase QTc and risk of torsade de pointes not seen clinically with azithromycin. Mechanism: Trojan horse which is converted into bactericidal metabolites by the electron transport chain of anaerobic bacteria. Only covers anaerobes. Can be used in broad range of infections e. Clostridioides difficile inferior to oral vancomycin; may be used as add-on agent in severe cases or in patients unable to take oral medications.
Generally avoid adding it to piperacillin-tazobactam or meropenem these agents have great anaerobic coverage; the only thing that metronidazole adds is Clostridioides difficile coverage. Medscape monograph: Metronidazole nafcillin back to contents nafcillin dosing Serious infections e. No adjustments for renal dysfunction. Monitor liver function tests every week pharmacology Excretion: Mostly cleared by the liver and biliary tract. Mechanism: Inhibits cell wall synthesis by binding to penicillin-binding proteins primarily 1a, 1b, and 2.
Recent evidence suggests that cefazolin might be superior for many MSSA infections more on this debate in the cefazolin section above.
Nafcillin penetrates the CSF unlike cefazolin. Sensitive strains of coagulase-negative staph Staph epidermidis, Staph haemolyticus, Staph lugdunensis Synergistic en vitro with either vancomycin or daptomycin against staph aureus clinical relevance to be determined. Nitrofurantoin macrocrystals Furadantin suspension, Macrodantin , mg q6hr. Relatively little drugs enters the gastrointestinal tract, so there is minimal effect on fecal flora and low risk of C.
Alkalotic urine may reduce its efficacy. Drug levels in the blood are not high enough to be effective against bacteremia. Mechanism of action: Nitrofurantoin is converted by bacterial flavoproteins into highly reactive electrophilic metabolites that have numerous activities, ultimately with bactericidal effect. Gram negatives: Covers most E. Misses: Morganella spp. Catheter-associated bacteriuria in the absence of pyelonephritis, sepsis, or bacteremia.
Prolonged prophylactic use may cause chronic hepatitis or peripheral neuropathy. Pneumonitis can occur over a shorter time frame, although pneumonitis is more likely among patients taking nitrofurantoin for weeks. Rare complications include pancreatitis and lactic acidosis.
Morbid obesity: higher doses may be required. Penetration is excellent, including some entry into inflamed meninges. Extremely high penetration of the bile may make this a good choice for biliary tract infections.
Mechanism: inhibits synthesis of bacterial cell wall. Misses: MRSA, vancomycin-resistant enterococci, coagulase-negative staph. Gram-negative coverage: Excellent coverage of most Enterobacteriaceae and Pseudomonas.
Intra-abdominal infections, biliary sepsis, urosepsis. Nosocomial pneumonia. Leukopenia, thrombocytopenia. Associated with lower rate of C. Prolonged prothrombin time specifically in renal failure. Mechanism: Inhibits bacterial RNA polymerase spectrum Staph aureus including MRSA , coagulase-negative staph Streptococcus pneumoniae, Group A streptococcus Acinetobacter baumannii Legionella, listeria Mycobacteria including tuberculosis use Note : Rifampin is generally used as an adjunctive agent to avoid emergence of resistance.
Prosthetic valve endocarditis Prosthetic joint infections Meningitis Community-acquired: targeted especially at treatment of PCN-resistant Streptococcus pneumoniae. High-dose tigecycline serious systemic infections : Loading dose of mg IV, then mg IV q No dose adjustment for renal dysfunction.
Low levels in blood and urine not good for bacteremia; maybe OK for urinary tract infection Mechanism: Inhibition of protein synthesis through 30s ribosomal binding blocking aminoacyl-tRNA same as doxycycline. Good gram-negative coverage but misses Pseudomonas, most Proteus and Providencia, and some Morganella.
Can be used against a range of multi-drug resistant gram negatives e. Covers listeria, Mycoplasma pneumoniae, Chlamydia pneumoniae. However, they are generally not front-line, given concerns about potential of increased mortality see FDA communication here. Home Pharmacy Mnemonics Resources. Table of Contents.
Piperacillin-tazobactam 3. Levofloxacin plus or mg IV once daily Metronidazole mg IV every eight hours Monotherapy with a carbapenem: Imipenem-cilastatin mg IV every six hours Meropenem 1 g IV every eight hours Doripenem mg IV every eight hours Ertapenem 1 g IV once daily Antibiotic doses should be adjusted appropriately for patients with renal insufficiency or other dose-related consideration.
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