Antimicrobial agents/therapy infection

Figure 66-4 provides an overview of patient- and antimicrobial agent-specific factors to consider when selecting an antimicrobial regimen. It further delineates monitoring of therapy and actions to take depending on the patients response to therapy. The duration of therapy depends on patient response and type of infection being treated. 

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... 

The treatment of intraabdominal infection most often requires the coordinated use of three major modalities (1) prompt drainage, (2) support of vital functions, and (3) appropriate antimicrobial therapy to treat infection not eradicated by surgery. Antimicrobials are an important adjunct to drainage procedures in the treatment of secondary intraabdominal infections however, the use of antimicrobial agents without surgical intervention usually is inadequate. For most cases of primary peritonitis, drainage procedures may not be required, and antimicrobial agents become the mainstay of therapy. 

Table 5. Parenterally administered antimicrobial agents which can be used alone or combined to provide effective coverage of the mixed aerobic-anaerobic infections arising from human colonic bacteria for patients requiring preventive therapy...

May be effective in the treatment of acute urinary tract infections caused by susceptible strains of gram-positive and gram-negative bacteria, especially Enterobacter sp. and Escherichia coii. It usually is less effective than other antimicrobial agents in the treatment of urinary tract infections caused by bacteria other than mycobacteria. Consider using only when the more conventional therapy has failed and when the organism has demonstrated sensitivity. 

Methenamine is primarily used for the long-term prophylactic or suppressive therapy of recurring UTIs. It is not a primary drug for therapy of acute infections. It should be used to maintain sterile urine after appropriate antimicrobial agents have been employed to eradicate the infection. 

Glucocorticoids are also used in the treatment of a number of HIV-related disorders, including Pneumocystis carinii pneumonia, demyelinating peripheral neuropathies, tuberculous meningitis, and nephropathy. Glucocorticoids are used as adjunctive therapy in Pneumo cystitis carinii pneumonia to decrease the inflammatory response and allow time for antimicrobial agents to exert their effects. In patients who are immunocompromised because of HIV infection, adjunctive steroids may be less beneficial in promoting survival. 

F. Role in therapy According to Micro-medex, the primary place in therapy of Actimmune is as prophylaxis against infection in patients with chronic granulomatous disease, and as an adjunct to conventional therapies (i.e., antimicrobial agents, bone marrow transplantation, leukocyte infusions) in these patients. 

Most infections should be treated with a single antimicrobial agent. Although indications for combination therapy exist, antimicrobial combinations are often overused in clinical practice. The unnecessary use of antimicrobial combinations increases toxicity and costs and may occasionally result in reduced efficacy due to antagonism of one drug by another. Antimicrobial combinations should be selected for one or more of the following reasons ... 

Ideally, the antimicrobial agent used to treat an infection is selected after the organism has been identified and its drug sensitivity established. However, in the critically ill patient, such a delay could prove fatal and immediate empiric therapy is indicated. 

When burn victims are receiving antibiotic therapy Pseudomonas can cause infection because of Its resistance to many antimicrobial agents. 

Oral therapy of infections is usually cheaper and avoids the risks associated with maintenance of intravenous access on the other hand, it may expose the gastrointestinal tract to higher local concentrations of antibiotic with consequently greater risks of antibiotic-associated diarrhoea. Some antimicrobial agents are available only for topical use to skin, anterior nares, eye or mouth in general it is better to avoid antibiotics that are also used for systemic therapy because topical use may be especially likely to select for resistant strains. Topical... 

The treatment of endometritis should include antimicrobial therapy based on culture and susceptibility testing (see Ch. 2). The treatments used commonly for bacterial and fungal uterine infections in horses are included in Tables 11.1 and 11.2. Fungal or yeast infections often result from the extensive use of antimicrobial agents in the uterus. These infections are difficult to treat and may cause permanent damage to the endometrium. An intrinsic problem with uterine yeast or fungal infections is the prolonged and potentially expensive therapy required. 

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