35. Methicillin resistant Staphylococcus aureus (MRSA) Antimicrobials for outpatient therapy of uncomplicated skin and soft tissue infections (Clinical guideline for management of suspected CA-MRSA infections,15 March 2007) Agent Potential advantage Precautions Usual adult dose (oral) Cotrimoxazole Oral Not for patient with sulfa allergy / G6PD 960mg bd Doxycycline High skin concentration Not for children <12 yo or pregnant women 200mg once, then 100mg bd Minocycline As above As above 100mg bd Clindamycin Inhibit toxin production Inducible resistance if erythromycin resistant 300-450mg tds Moxifloxacin Oral Resistance may develop during therapy 400mg qd
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48. Emerging and reemerging infectious diseases Antibiotic resistance Novel agents and their clinical uses Part 2 Gram-negative superbugs
Always think about TOCC in Febrile ± Influenza-like illness patients – T ravel History – recent 7 days to farms in endemic area – O ccupation – Lab worker or wild birds, poultry related – C ontact – human case and wild bird, poultry – C lustering – clustering of persons with fever and pneumonia
Respiratory fluoroquinolone (levofloxacin, moxifloxacin) covers both the 3 typical and 3 atypical organisms, but resistance to S pneumoniae may develop quickly, not first line therapy for estabilshed S pneumoniae infection
ICU setting Timentin and ceftazidime are active vs. Gram-negatives and Pseudomonas, but are less active vs. Streptococcus pneumoniae
Respiratory fluoroquinolone (levofloxacin, moxifloxacin) covers both the 3 typical and 3 atypical organisms, but resistance to S pneumoniae may develop quickly, not first line therapy for estabilshed S pneumoniae infection Bronchiectasis is destruction and widening of the large airways
Minimum inhibitory concentration tested for Penicillin G
Telithromycin has activity vs both typical and atypical organisms responsible for most cases of CAP
MDRSP refers to isolates resistant to 2 or more of the following antibiotics: penicillin, second-generation cephalosporins, macrolides, tetracycline, and trimethoprim/sulfamethoxazole.
Well dermarcated: well defined boundary
Cotrimoxazole-DS = cotrimoxazole double strength One septrin tab = 480mg DS = two tabs = 960mg
Staph bacteria are classified as VISA or VRSA based on laboratory tests. Laboratories perform tests to determine if staph bacteria are resistant to antimicrobial agents that might be used for treatment of infections. For vancomycin and other antimicrobial agents, laboratories determine how much of the agent it requires to inhibit the growth of the organism in a test tube. The result of the test is usually expressed as a minimum inhibitory concentration (MIC) or the minimum amount of antimicrobial agent that inhibits bacterial growth in the test tube. Therefore, staph bacteria are classified as VISA if the MIC for vancomycin is 4-8µg/ml, and classified as VRSA if the vancomycin MIC is > 16µg/ml. top
MDRSP refers to isolates resistant to 2 or more of the following antibiotics: penicillin, second-generation cephalosporins, macrolides, tetracycline, and trimethoprim/sulfamethoxazole.
Acute cholecystitis: distension of gallbladder, often with stones
Tazocin + aminoglycoside stated in IMPACT But associated resistance vs. penicillin is a problem
Acinetobacter Acinetobacter species are aerobic gram-negative bacteria that are widely distributed in soil and water and can occasionally be cultured from skin, mucous membranes, secretions, and the hospital environment. Acinetobacter baumannii is the species most commonly isolated. A baumannii has been isolated from blood, sputum, skin, pleural fluid, and urine, usually in device-associated infections. Acinetobacter encountered in nosocomial pneumonia often originates in the water of room humidifiers or vaporizers. In patients with acinetobacter bacteremia, intravenous catheters are almost always the source of infection. In patients with burns or with immune deficiencies, acinetobacter acts as an opportunistic pathogen and can produce sepsis. Acinetobacter strains are often resistant to antimicrobial agents, and therapy of infection can be difficult. Susceptibility testing should be done to help select the best antimicrobial drugs for therapy. Acinetobacter strains respond most commonly to gentamicin, amikacin, or tobramycin and to newer penicillins or cephalosporins.
If resistant to isoniazid but sensitive to rifampin Rifampin, pyrazinamide, ethambutol, fluoroquinolone Duration: 6 months If resistant to rifampin but sensitive to isoniazid Isoniazid, ethambutol, fluoroquinolone, pyrazinamide Duration: 12-18 months If resistant to isoniazid and rifampin Fluoroquinolone, pyrazinamide, ethambutol, injectable agent ± alternative agent Duration: 18-24 months If resistant to isoniazid, rifampin, (pyrazinamide/ethambutol) Fluoroquinolone, (pyrazinamide/ethambutol if active), injectable agent and 2 alternative agents Duration: 18-24 months
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