Penicillinase pneumoniae

Class A Serine p-lactamases SHV-1 penicillinase in K. pneumoniae, and Koxy with activity against certain third generation cephalosporins in K. oxytoca BlaZ staphylococcal penicillinase TEM, SHV, VEB, PER and CTX-M penicillinases and ESBLs (P-lactamases with activity against third generation cephalosporins and aztreo-nam) KPC, IMI/NMC and SME carbapenemases... 

Like other semisynthetic penicillins, methicillin exhibits an antibacterial effect similar to that of benzylpenicillin. The main difference between methicillin and benzylpenicillin is that it is not inactivated by the enzyme penicillinase, and therefore it is effective with respect to agents producing this enzyme (staphylococci). It is used for infections caused by benzylpenicillin-resistant staphylococci (septicemia, pneumonia, empyemia, osteomyelitis, abscesses, infected wounds, and others). Synonyms of this drug are cinopenil, celbenin, staphcillin, and others. 

Skin and skin structure infections- Skin and skin structure infections, including abscesses, cellulitis, infected skin ulcers, and wound infections caused by S. aureus (including penicillinase-producing strains) Streptococcus pyogenes, group D streptococcus including . faecalis, Acinetobacter sp. including iA. calcoaceticus] Citrobactersp.] E. coli] Enterobacter cloacae, K. pneumoniae]... 

It is clinically important to understand the nature of the mechanism of resistance to an antibiotic drug. For example, the -lactam resistance of Streptococcus pneumoniae is due to the appearance of altered penicillinbinding proteins. Thus, the use of a combination of a 3-lactam and a penicillinase inhibitor, such as clavulanate, wUl not overcome streptococcal -lactam resistance, because the mechanism of resistance is not due to the production of a penicillinase. 

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. 

Rx of pneumonia, skin, soft tissue Infxns, osteomyelitis caused by penicillinase-producing staphylococci Action Bactericidal X cell wall synth Dose Adults. 250-500 mg qid Feds <40 kg, 12.5-100 mg/kg/d - qid take on empty stomach Caution [B, ] Contra Component orPCN sensitivity Disp Caps 125, 250, 500 mg soln 62.5 mg/5 mL SE N/D, abd pain Interactions T Effects W/ disulfiram, probenecid T effects OF MRX, X effects W/ macrolides, tetracyclines, food X effects OF OCPs, warfarin EMS Monitor for signs of electrolyte disturbances and hypovolemia d/t D OD May cause N/V/D, behavior changes, urinary retention, skin rash and Szs symptomatic and supportive... 

Staphylococcus aureus Abscesses bacteremia cellulitis endocarditis osteomyelitis pneumonia others If methicillin-sensitive nafcillin or oxacillin If methicillin-resistant vancomycin gentamicin or rifampin 1 st-generation cephalosporin clindamycin erythromycin trimethoprim-sulfamethoxazole a penicillin + a penicillinase inhibitor... 

First generation Cephalosporins designated first generation (Figure 30.8) act as penicillin G substitutes that are resistant to the staphylococcal penicillinase. They also have activity against Proteus mirabilis. Escherichia coli, and Klebsiella pneumoniae (the acronym PEcK has been suggested). 

K. pneumoniae, P. aeruginosa, Enterobacter sp., Serratia sp., P. mirabilis, Proteus sp., and S. aureus (penicillinase- and nonpenicillinase-producing strains)... 

Soluble in water. Dextrorotatory. Inactivated by penicillinase as is penicillin G, but differs from the coihmon penicillin by its antibacterial activity and hydrophilic character. When an aq soln is kept at pH 2.7 and 3T for 2 hrs. there is a loss of antibacterial activity and an increase in dextrorotation. Active against Sarcina lutea, Proteus vulgaris. Salmonella typhimurium, Diplococcus pneumoniae. Shows practically no activity against B. subfilis and Staph, aureus. The toxicity is somewhat less than that of penicillin G. although penicillin N is excreted more slowly. 

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