Antibiotics Antimicrobial therapy

Brain abscesses are localized collections of pus within the cranium. These infections are difficult to treat due to the presence of walled-off infections in the brain tissue that are hard for some antibiotics to reach. In addition to appropriate antimicrobial therapy (a discussion of which is beyond the scope of this chapter), surgical debridement is often required as an adjunctive measure. Surgical debridement also may be required in the management of neurosurgical postoperative infections. 

Every patient receiving antimicrobial therapy for skin and soft tissue infections must be monitored for efficacy and safety. Efficacy typically is manifested by reductions in temperature, white blood cell count, erythema, edema, and pain that begin within 48 to 72 hours. To ensure safety, dose antibiotics according to renal and hepatic function as appropriate, and monitor for and minimize adverse drug reactions, allergic reactions, and drug interactions. 

If GAS is identified as the sole causative organism from deep tissue culture, antimicrobial therapy can be narrowed to high-dose IV penicillin G plus clindamycin. Antibiotic therapy should be continued until further operative debridements are unnecessary, the patient displays substantial clinical improvement, and fevers have abated for at least 48 to 72 hours.3... 

The severity of a patient s infection, based on the PEDIS scale, guides the selection of empirical antimicrobial therapy. While most patients with grade 2 diabetic foot infections can be treated as outpatients with oral antimicrobial agents, all grade 4 and many grade 3 infections require hospitalization, stabilization of the patient, and broad-spectrum IV antibiotic therapy.31... 

Patients with complicated typhoid fever (i.e., metastatic foci, ileal perforation, etc.) should receive parenteral therapy with ciprofloxacin 400 mg twice daily or ceftriaxone 2000 mg once daily. Antimicrobial therapy can be completed with an oral agent after initial control of the symptoms of typhoid fever. In persons with AIDS and a first episode of Salmonella bacteremia, a longer duration of antibiotic therapy (1-2 weeks of parenteral therapy followed by 4 weeks of oral fluoroquinolone) is recommended to prevent relapse of bacteremia. 

Symptoms can start as early as the first day of antimicrobial therapy or several weeks after antibiotic therapy is completed. 

Antimicrobial therapy is the cornerstone of treatment in UTIs. This therapy should ideally be well tolerated, narrow in antimicrobial spectrum, lend itself to patient compliance (taken as infrequently as possible), have adequate concentrations at the site of the infection, and have good oral bioavailability. Table 76-2 reviews antibiotics frequently used to treat UTIs with comments on their use, and Table 76-3 reviews frequency, duration, and doses of those antibiotics. 

The patient received 4 weeks of intravenous antimicrobial therapy following debridement. Due to clinical improvement, the physician contacts you for a recommendation for an oral antibiotic to complete a total of 6 weeks of therapy. 

Integration of both pharmacokinetic and pharmacodynamic properties of an agent is important when choosing antimicrobial therapy to ensure efficacy and prevent resistance. Antibiotics may demonstrate concentration-dependent (aminoglycosides and fluoroquinolones) or time-depen-dent (/l-1 acta ms) bactericidal effects. 

Empiric antimicrobial therapy should be instituted as soon as possible to eradicate the causative organism (Table 36-2). Antimicrobial therapy should last at least 48 to 72 hours or until the diagnosis of bacterial meningitis can be ruled out. Continued therapy should be based on the assessment of clinical improvement, cultures, and susceptibility testing results. Once a pathogen is identified, antibiotic therapy should be tailored to the specific pathogen. 

Antimicrobial therapy is used to treat otitis media however, a high percentage of children will be cured with symptomatic treatment alone. Antibiotic use reduces the duration of symptoms by about 1 day. 

Aggressive, early antimicrobial therapy is critical in the management of septic patients. The regimen selected should be based on the suspected site of infection, likely pathogens, and the local antibiotic susceptibility patterns, whether the organism was acquired from the community or a hospital, and the patient s immune status. 

Nowadays, one stated objective of much of the more imaginative mastitis research is the reduction in our dependence on antibiotics and other exogenous chemicals to control bovine mastitis. Achievement of this goal is nowhere in sight. And so, we are left dependent upon antimicrobial therapy, despite its many limitations, as a major element in control strategy for bovine mastitis. 

When considering antimicrobial therapy in a patient with fever, one should answer the following questions. First, is the fever caused by an infection If affirmative, data are needed to determine the severity of the infection, the site of infection, and the causal micro-organism(s). Second, when the cause of the fever is infectious, one should ask is treatment with antimicrobial drugs needed Many soft tissue infections including impetigo and decubital ulcers are best treated with local antiseptics and/or wound debridement without the use of antibiotics. If the chance to cure the infection with antimicrobial... 

Most infections are caused by gram-negative bacteria, mostly Escherichia coli. In recurrent UTI, after repeated courses of antimicrobial therapy, other organisms and antibiotic resistance can be expected. 

Is treatment with an antibiotic necessary Symptomatic patients always need treatment. Asymptomatic bacteriuria (=10 bacteria/ml in two separate urine cultures) only needs treatment in pregnancy, in children and in obstructions of the urinary tract. Obstmctions in urinary flow must be treated before an antibiotic is started. There is no clear evidence that hydration or acidification of urine improves the results of antimicrobial therapy. 

Antiseptics and antibiotics are the two hallmarks of antimicrobial therapy. Although there are several reports about local and systemic antimicrobials for therapy of eczematous skin diseases, there is only little data about prevention. 

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