Health Surveillance and Disease Prevention and Control / Communicable Diseases / Antimicrobial Resistance
Model for a Clinical Handbook for the Treatment of Infectious Diseases | ||||||||||
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Full Text in Spanish (PDF, 102 pp, 1014 Kb; chapter heading translated for user orientation) Annexes PAHO Antimicrobial Resistance Page - WHO Drug Resistance Page |
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This handbook in Spanish was prepared for use in Latin American countries. Antimicrobial substances are those either produced by microorganisms (antibiotics produced by bacteria, fungi or actinomicetos) or chemically synthesized (sulfa drugs, quinolones) that have the capacity to destroy, impede, or delay the multiplication of others microorganisms. In medical practice, both are called "antibiotics." Antibiotic therapy is used to treat patients showing symptoms and clinical signs of infection. Its adequate use requires collecting data both on the patient and on the context (Table 1). Antibiotic therapy can be used empirically when the causative agent is unknown, or etiologically when the agent has already been identified. In both circumstances, the antibiotic selected should be both effective and safe (Table 2).
Although the isolation of the etiologic agent is beneficial, in that it facilitates specifically choosing the most adequate treatment, it is not always possible. However, it should the rule in cases of hospital-acquired infections and in those with serious community infection. In any case, any interpretation of laboratory data should involve the consideration of clinical symptoms, since findings can stem from a colonization and not from just one infection. The identification of the etiologic agent can be obviated when evidence exists that the infection is the result of a given microorganism and when experience indicates that the latter is susceptible to a given antibiotic: for example, with sexually transmitted infections (STIs), pneumonia and community cystitis. Furthermore, not all infections justify treatment with antibiotics. Examples occur with asymptomatic bacteriuria (except in pregnant women or in immuno-deficient patients), superficial abscesses that can be drained, diarrhea without blood, and secondary fever following the introduction for a brief period of a deep intravenous catheter.
The presumed diagnosis of an infection is based on clinical and epidemiological data. If both justify treatment with antibiotics, the selection of the antimicrobial drug for treatment will depend as much on the information that health workers have at their disposal as on the general state of the host, the site of the infection, the epidemiological data on and characteristics of the antimicrobial drug used and on the potential causative agent. Whenever it becomes necessary to administer treatment based on medical evidence, any suspicion of a causative agent will depend on the possibility of determining the microorganism that has greatest statistical probability to cause the infection in that particular clinical-epidemiological situation. Empirical treatment is justified when diagnosis of the causative agent is not available or when the urgency of the case thus requires it. However, before initiating treatment, material should be obtained not only on the microscopic examination facilitating treatment definition but also so that the microbiological laboratory can attempt to isolate and identify the etiologic agent and carry out tests to establish its susceptibility to antibiotics. The sooner treatment with the proper antimicrobial drug starts, the better the chances for it to benefit both the patient and his/her community. With regard to the patient, the evaluation of the therapeutic action of selected antibiotic is based on clinical and laboratory parameters (Table 3).
When laboratory findings indicate the existence of more than one antimicrobial drug capable of acting against the causative agent, the one will be selected that
Treatment with more than one antibiotic at the same time is only justified in cases of serious infections under evidence-based treatment or when a diagnosis of the causative agent exists but where preventing resistance is a concern (for example, in the case of infection by Pseudomonas aeruginosa, Mycobacterium tuberculosis, and endocarditis via Enterococcus faecalis); mixed infections (for example, cases of abdominal or pelvic infection), or when the patient has two diseases with different causative agents (for example, tuberculosis or leprosy with infections from another etiology). Regulating the Use of Antimicrobial Drugs The rational use of antimicrobial drugs in institutions requires the existence of an institutional Committee to Control Hospital Infections and a Drug Therapy Committee. Both will be responsible for standardizing the use of antimicrobial drugs in the institution, in accordance with established criteria and based on existing experience with drugs. In addition, the committees will enforce prescription control, especially of third-and fourth-generation cephalosporins, aminoglycosides, quinolones and new betalactamica. At times, those responsibilities might be handled by a single committee. However, there are also institutional conditions that facilitate the rational use of antibiotics (Table 4). The use of antimicrobial drugs and their control will depend on the type of institution in question and will be different for those housing chronic cases, those offering pediatric or adult primary care, and facilities with intensive care units. Furthermore, it will also depend on the existence of sufficient institutional resources to ensure that control can be effectively carried out.
Two types of control situations can be considered, with and without therapeutic reserve:
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