Antimicrobial empirical therapy with

Early empirical therapy is the administration of systemic antifungal agents at the onset of fever and neutropenia. Empirical therapy with systemic antifungal agents is administered to granulocytopenic patients with persistent or recurrent fever despite the administration of appropriate antimicrobial therapy. 

Empirical therapy should be based on patient- and antimicrobial-specific factors such as the anatomic location of the infection, the likely pathogens associated with the presentation, the potential for adverse effects, and the antimicrobial spectrum of activity. 

Most initial antimicrobial therapy is empirical because cultures usually have not had sufficient time to identify a pathogen. Empirical therapy should be based on patient- and antimicrobial-specific factors such as the anatomic location of the infection, the likely pathogens associated with the presentation, the potential for adverse effects in a given patient, and the antimicrobial spectrum of activity. Prompt initiation of appropriate therapy is paramount in hospitalized patients who are critically ill. Patients who receive initial antimicrobial therapy that provides coverage against the causative pathogen survive at twice the rate of patients who do not receive adequate therapy initially.8... 

The patient was admitted to the hospital with a presumptive diagnosis of health care-associated pneumonia (based on the recent hospitalization). He received intravenous hydration with normal saline, 5 L oxygen via face mask, an insulin infusion to control his glucose, and empirical antimicrobial therapy with piperacillin-tazobactam 2.25 g intravenously every 6 hours and vancomycin 1 g intravenously every 24 hours. All other medications are continued with the exception of the diabetes medications. 

Empiric therapy for febrile neutropenic patients - As monotherapy for empiric treatment of febrile neutropenic patients. In patients at high risk for severe infection (including patients with a history of recent bone marrow transplantation, with hypotension at presentation, with an underlying hematologic malignancy, or with severe or prolonged neutropenia), antimicrobial monotherapy may not be appropriate. Insufficient data exist to support the efficacy of cefepime monotherapy in such patients. 

Antimicrobial agents are frequently used before the pathogen responsible for a particular illness or the susceptibility to a particular antimicrobial agent is known. This use of antimicrobial agents is called empiric (or presumptive) therapy and is based on experience with a particular clinical entity. The usual justification for empiric therapy is the hope that early intervention will improve the outcome in the best cases, this has been established by placebo-controlled, double-blind prospective clinical trials. For example, treatment of febrile episodes in neutropenic cancer patients with empiric antimicrobial therapy has been demonstrated to have impressive morbidity and mortality benefits even though the specific bacterial agent responsible for fever is determined for only a minority of such episodes. 

Raymond et al. reported on a rotation study in a surgical intensive care unit with a different twist.Patients were stratified as either having sepsis/peritonitis or pneumonia, and empiric therapy was cycled every 3 months by syndrome. Fourteen hundred fifty-six admissions and 540 infections were treated over a 2-year period. With similar severity of illness during the before and after periods (mean APACHE II = 19), the authors demonstrated a reduction of length of stay from a mean of 62 days to 39 days, a reduction of vancomycin-resistant enterococcal and methicillin-resistant staphylococcal infection from 14 per 100 admissions to 8 per 100 admissions and death due to any cause dropped from 25 in the before period to 18 in the rotation period. Antimicrobial susceptibility and several other key parameters needed to evaluate the effectiveness of this program were not reported. 

Recommended empirical therapy differs among outpatients, hospitalized patients, and hospitalized patients admitted to an intensive care unit (Table 106-12). Additionally, antimicrobial therapy should be initiated in hospitalized patients with acute pneumonia within 8 hours of admission because an increase in mortality has been demonstrated when therapy was delayed beyond 8 hours of admission. 

EORTC International Antimicrobial Therapy Cooperative Group. (1987). Ceftazidime combined with short and long course amikacin for empirical therapy of gram-negative bacteraemia in cancer patients with granulocytopenia. New Eng J Med, 317, 1692-1698. 

Many areas of the human body are colonized with bacteria— this is known as normal flora. Infections often arise from one s own normal flora (also called an endogenous infection). Endogenous infection may occur when there are alterations in the normal flora (e.g., recent antimicrobial use may allow for overgrowth of other normal flora) or disruption of host defenses (e.g., a break or entry in the skin). Knowing what organisms reside where can help to guide empirical antimicrobial therapy (Fig. 66-1). In addition, it is beneficial to know what anatomic sites are normally sterile. These include the cerebrospinal fluid, blood, and urine. 

Empirical selection of antimicrobial spectrum of activity should be related to the severity of the illness. Generally, acutely ill patients may require broader-spectrum antimicrobial coverage, whereas less ill patients may be managed initially with narrow-spectrum therapy. While a detailed description of antimicrobial pathogen- specific spectrum of activity is beyond the scope of this chapter, this information can be obtained readily from a number of sources.9,10... 

High-dose penicillin G traditionally has been the drug of choice for the treatment of pneumococcal meningitis. However, due to increases in pneumococcal resistance, the preferred empirical treatment now includes a third-generation cephalosporin in combination with vancomycin.13 All CSF isolates should be tested for penicillin and cephalosporin resistance by methods endorsed by the CLSI. Once in vitro sensitivity results are known, therapy may be tailored (Table 67-3). Patients with a history of type I penicillin allergy or cephalosporin allergy may be treated with vancomycin. Treatment should be continued for 10 to 14 days, after which no further maintenance therapy is required. Antimicrobial prophylaxis is not indicated for close contacts. 

Therefore, despite the 18% and 25% resistance to penicillin and macrolides, the clinical failure rate is less than this. Owing to the empirical treatment of CAP in the outpatient setting, establishing a meaningful clinical failure rate with any therapy is difficult to do. No studies have been performed that established a correlation between clinical failure rates with a particular antimicrobial agent and the percentage of resistant bacterial pathogens. 

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... 

Since remarkable symptomatic improvement can be achieved in most patients, antibiotic therapy is obviously the cornerstone of the treatment of SIBO [136], Ideally, the choice of an antimicrobial agent should be based on in vitro susceptibility testing of the bacteria in the small bowel of the individual patient. However, because it is impractical to obtain this information in most cases, the choice of the antibiotic is largely empiric and based on results of published series involving small intestinal cultures [137], Whereas most patients with SIBO have aero-... 

Antimicrobial agents are frequently used before the pathogen responsible for a particular illness or the susceptibility to a particular antimicrobial agent is known. This use of antimicrobial agents is called empirical (or presumptive) therapy and is based upon experience with a particular clinical... 

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