Staphylococcal infections, treatment

Employed as a sodium salt, fusidic acid (Fig. 5.14B) is achve against many types of Gram-positive bacteria, especially staphylococci, although streptococci are relatively resistant. It is employed in the treatment of staphylococcal infections, including strains resistant to other antibiotics. However, bacterial resistance may occur in vitro and in vivo. 

T Cells May Contribute to the Defects in Innate Immune Response in Atopic Dermatitis Most patients with atopic dermatitis are colonized with S. aureus and experience exacerbation of their skin disease after infection with this organism [2]. In patients with S. aureus infection, treatment with anti-staphylococcal substances can result in the reduction of skin disease. Binding of S. aureus to the epidermis is enhanced by atopic skin inflammation. This is supported by clinical studies demonstrating that treatment with topical corticosteroids or tacrolimus reduces S. aureus counts in atopic dermatitis. 

Duration - Duration of therapy varies with the type and severity of infection as well as the overall condition of the patient therefore, determine duration by the clinical and bacteriological response of the patient. In severe staphylococcal infections, continue nafcillin therapy for at least 14 days. Continue therapy for at least 48 hours after the patient has become afebrile and asymptomatic and cultures are negative. The treatment of endocarditis and osteomyelitis may require a longer duration of therapy. 

Note Do not use tetracyclines for streptococcal disease unless organism has been shown to be susceptible. Tetracyclines are not the drugs of choice in treatment of any type of staphylococcal infection. 

Fusidic acid is a product of, among others, the fungus Fusidium coccineum. It has a steroidal structure and has mainly bacteriostatic activity. Its mechanism of action is based on inhibition of bacterial protein synthesis. Its indications are limited to the treatment of severe staphylococcal infections, usually in combination with another antistaphylococcal agent to prevent the emergence of resistance. 

Rifampin is a first-line antitubercular drug used in the treatment of all forms of pulmonary and extrapul-monary tuberculosis. Rifampin is an alternative to isoniazid in the treatment of latent tuberculosis infection. Rifampin also may be combined with an antileprosy agent for the treatment of leprosy and to protect those in close contact with patients having H. influenza type b and N. meningitidis infection rifampin is also used in methicillin-resistant staphylococcal infections, such as osteomyelitis and prosthetic valve endocarditis. 

An isoxazolyl penicillin such as oxacillin, cloxacillin, or dicloxacillin, 0.25-0.5 g orally every 4-6 hours (15-25 mg/kg/d for children), is suitable for treatment of mild to moderate localized staphylococcal infections. All are relatively acid-stable and have reasonable bioavailability. However, food interferes with absorption, and the drugs should be administered 1 hour before or after meals. 

Rifampin combined with a second agent is used to eradicate staphylococcal carriage. Rifampin combination therapy is also indicated for treatment of serious staphylococcal infections such as osteomyelitis and prosthetic valve endocarditis. 

Erythromycin is a macrolide antibiotic produced by Streptomyces erythreus. It is considered the most active macrolide for treatment of staphylococcal infections in cases of penicillin resistance. It is used parenterally at a dosage of 3-5 mg/kg bw, in intramammary form at 300 mg/quarter, and orally at 20-50 mg/kg bw. For treatment of mycoplasmal infections in poultry, an oral medication... 

Oleandomycin is a macrolide antibiotic produced by Streptomyces antibi-oticus. Oleandomycin and its triacetylated form, troleandomycin, are less effective than erythromycin against staphylococcal infections. They are usually administered orally or intravenously intramuscular administration is avoided because of the pain and tissue irritation it induces. Oleandomycin is also used in intramammary treatments and as a feed additive for growth promotion purposes. 

Lincomydn is an antibiotic produced by Streptomyces lincolnensis. It is used in monopreparations or in combination with other antibiotics such as spectinomycin, sulfamethazine, and gentamicin, for the initial treatment of mild to moderate staphylococcal infections in a variety of animal species. It can be administered orally to poultry at dosages equivalent to up to 50 mg/kg hw/day for up to 7 days, and to swine at dosages equivalent to up to 10 mg/kg bw/day for up to 21 days. In calves, sheep, goats, and swine, it can be administered intramuscularly at dosages of up to 15 mg/kg bw/day for up to 4-7 days. It is also added in feeds for growth-promoting purposes. 

Novobiocin (Fig. 3.9) is a narrow-spectrum antibiotic with antibacterial activity against many gram-positive pathogens. It is frequently used, in combination with penicillin, for treatment of bovine mastitis by intramammary infusion of 200 mg/ quarter in two quarters, and to control fowl cholera and staphylococcal infections in chickens and turkeys at a level of 200-350 g/ton in feed. 

They have been used prophylactically and therapeutically in the treatment of topical infections due to Staphylococcus aureus and other bacteria and fungi. In clinical trials, the nickel chelate of 3,4,7,8-tetramethyl-l,10-phenanthroline was effective against staphylococcal infection in the newborn, in patients undergoing obstetric surgery and in the treatment of adolescents infected with acne vulgaris139). 

Rifampin is used in a variety of other clinical situations. An oral dosage of 600 mg twice daily for 2 days can eliminate meningococcal carriage. Rifampin, 20 mg/kg/d for 4 days, is used as prophylaxis in contacts of children with Haemophilus influenzae type b disease. Rifampin combined with a second agent is used to eradicate staphylococcal carriage. Rifampin combination therapy is also indicated for treatment of serious staphylococcal infections such as osteomyelitis and prosthetic valve endocarditis. Rifampin has been recommended also for use in combination with ceftriaxone or vancomycin in treatment of meningitis caused by highly penicillin-resistant strains of pneumococci. 

Orbital cellulitis is an infection of the orbital contents posterior to the orbital septum. Streptococci and staphylococci are common bacterial isolates. Many regimens exist for empiric treatment of this disease, but no regimen has been tested in clinical trials. Intravenous nafcillin can be used as initial therapy for orbital cellulitis, especially when a staphylococcal infection is suspected or known (see Table 11-1). 

Schmidt-loanas M, de Roux A, Lode H, New antibiotics for the treatment of severe staphylococcal infection in the critically ill patient, Curr Op Crit Care, 2005,11 481 -86. 

Although cross-resistance to other antibiotics is reported not to develop with novobiocin, resistant S. aureus strains are known. (Consequently, the medical use of novobiocin is reserved for the treatment of staphylococcal infections resistant to other antibiotics and sulfas and for patients aller-... 

Rifampicin possesses significant bactericidal activity at very low concentrations against staphylococci. Unfortunately, resistant mutants may arise very rapidly, both in vitro and in vivo. It has thus been recommended that rifampicin should be combined with another antibiotic, e.g. vancomycin, in the treatment of staphylococcal infections. 

There is one minor condition - stye (hordeolum) - for which pharmacists can offer advice and treatment. It is caused by staphylococcal infection of a hair follicle at the base of an eyelash. 

Dodek P, Phillip P. Questionable history of immediate-type hypersensitivity to penicillin in staphylococcal endocarditis Treatment based on skin test results versus empirical alternative treatment—A decision analysis. Clin Infect Dis 1999 29 1251-1256. 

They chose an Oxford policeman, Albert Alexander, who was desperately ill with advanced streptococcal and staphylococcal infections following a simple sore on his mouth (a further reminder of how precarious life was before the advent of antibiotics ). He had already received extensive treatment with sulfonamides, but to no avail. On February 12, he was given an intravenous injection of 200 mg of penicillin followed by further injections of 100mg every three hours. Within 24hours, he showed a dramatic improvement and within five days he was clearly well on the road to recovery. Sadly, the supplies of penicillin ran out and despite extracting his urine to recover some of the drug for recycling, his treatment could not be continued and he relapsed and died of septicaemia on March 15 - a timely indication that eradication of all bacteria must be achieved if a cure is to be obtained. 

Dicloxacillin is a penicillinase-resistant penicillin that inhibits bacterial cell-wall mucopeptide synthesis. It is indicated in the treatment of infections caused by peniciUinase-producing staphylococcal infection and in initial therapy of suspected staphylococcal infection. 

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