Penicillins antistaphylococcal

S. aureus MSSA Antistaphylococcal penicillin P-Lactam allergy ... 

Cefazolin penetrates well into most tissues. It is a drug of choice for surgical prophylaxis. Cefazolin may be a choice in infections for which it is the least toxic drug (eg, penicillinase-producing E coli or pneumoniae) and in persons with staphylococcal or streptococcal infections who have a history of penicillin allergy other than immediate hypersensitivity. Cefazolin does not penetrate the central nervous system and cannot be used to treat meningitis. Cefazolin is an alternative to an antistaphylococcal penicillin for patients who are allergic to penicillin. 

Except antistaphylococcal penicillins (eg, nafcillin and dicloxacillin). 4Except trovafloxacin and moxifloxacin. 

The use of an antagonistic antimicrobial combination does not preclude other potential beneficial interactions. For example, rifampin may antagonize the action of antistaphylococcal penicillins or vancomycin against staphylococci. However, the aforementioned antimicrobials may prevent the emergence of resistance to rifampin. 

Antistaphylococcal penicillins Methicillin [meth i SILL in], naf-cillin [naf SILL in], oxacillin [ox a SILL in], cloxacillin [klox a SILL in], and dicloxacillin [dye klox a SILL in] are penicillinase-resistant penicillins. Their use is restricted to the treatment of infections caused by penicillinase-producing staphylococci. Because of its toxicity, methicillin is rarely used. Methicillin-resistarft strains of Staphylococcus aureus (MRSA), currently a serious source of nosocomial (hospital-acquired) infections, are usually susceptible to vancomycin, and rarely to ciprofloxacin or rifampin. 

Correct answer a D. Amoxicillin plus clavulanic acid is an extended spectrum formulation that is penicillinase resistant because of the presence of a p-lactamase inhibitor, and is stable in acid. Methicillin, an antistaphylococcal penicillin, is penicillinase resistant but is not stable in acid. Carbeniciliin and piperacillin, antipseudomonai penicillins, are neither penicillinase resistant nor stable in acid. Penicillin V is a narrow spectrum antibiotic that is not penicillinase resistant but is stable in acid. 

The authors concluded that short-term therapy with piperacillin, imipenem + cilastatin, or the combination could cause the same type of liver damage as described with co-amoxiclav and antistaphylococcal penicillins. 

Nafcillin, an antistaphylococcal penicillin, is an appropriate IV antibiotic for the treatment of cellulitis requiring hospitalization. Appropriate alternatives include cefazolin or clindamycin. Second- and third-generation cephalosporins offer no advantage over the listed regimens since they are broader in spectrum and more expensive. While gramnegative organisms such as Escherichia coli, Pseudomonas... 

All bite wounds (either animal or human) should be irrigated thoroughly with large volumes of sterile normal saline, and the injured area should be immobilized and elevated. Infections developing within the first 24 hours after a dog or cat bite are caused most often by Pasteurella multocida and should be treated with penicillin or amoxicillin for 10 to 14 days. Infections developing more than 36 to 48 hours after an animal bite are most likely caused by staphylococci or streptococci and should be treated with an antistaphylococcal penicillin or cephalosporin. 

Antistaphylococcal penicillins have been associated with drug-induced acute interstitial nephritis (AIN). A55-year-old man developed AIN after receiving nafcillin for 7 days for the treatment of mefhicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia. Due to the difficult diagnosis and recognition of AIN, clinicians should be aware of the ability of this agent to cause this disorder [41 ]. 

Three patients experienced decreased INR after the administration of cloxacillin in combination with warfarin. Antistaphylococcal penicillins have been associated with decreased INR. Potential mechanisms for this include competition for protein binding and induction of CYP450 enz3unes. This is the first case series with this interaction of warfarin with cloxacillin specifically. In this case series, the INR effect was seen in 4 days, but INR remained sub-therapeutic for 3-4 weeks after cloxacillin was discontinued. Clinicians should be aware of this effect and consider choosing alternate antibiotic therapy when possible [50 ]. 

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