Introduction To Antibiotic Use
Antimicrobial resistance (AMR) is a global threat today and has overshadowed the potential gain in reducing deaths due to infections. It is estimated that by the year 2050, Asia will have 4.7 million deaths that could be directly attributed to AMR. Antimicrobial resistance is rampant in India with up to 12-59 % of E. coli being extended beta lactamase (ESBL) producers and up to 30% being carbapenemase producers (CP).
Klebsiella pneumoniae has emerged over the last few years as a highly resistant pathogen with up to 50% resistance to carbapenems and rapidly increasing resistance to polymyxins. In addition, methicillin resistance in Staphylococcus aureus is seen in up to 30% of S. aureus isolates nationally. It is well documented that antibiotic abuse is one of the major drivers of antibiotic resistance and thus optimising usage of antibiotics is the need of the hour. India is the largest consumer of antibiotics in the world i.e., 13 billion standard units in 2010 and from 2000 to 2010 the per capita consumption increased by 66%. In May 2015, the World Health Assembly adopted a resolution to endorse a global action plan on antimicrobial resistance.
Principles of rational antibiotic use
Human antimicrobial misuse or overuse is one of the main drivers of AMR and in the presence of a dry antibiotic pipeline, it becomes imperative that we learn to use antibiotics judiciously and responsibly. In 2010, India was adjudicated to be the world’s largest consumer of antibiotics and hence curbing injudicious use of antibiotics is a must.
Antibiotic abuse happens due to common fallacies such as a belief that broad spectrum antibiotics are “safer” and failure to distinguish between bacterial infections and nonbacterial infections and non-infectious syndromes. In addition, antibiotics for durations longer than necessary, redundant cover (like double gram negative or double anaerobic over) or treatment of colonizers or contaminants also constitute inappropriate antibiotic use. A stewardship program implementing rational antibiotic use is mandatory to curb irrational antibiotic use.
Antimicrobial stewardship is defined as a set of coordinated interventions designed to measure and improve the appropriate use of antibiotics by promoting the selection of the optimal choice, dose, duration and route of the antibiotic which in turn lead to improved patient outcomes and decreased adverse effects.
Management of Acute Fever
Antibiotic use will need to be classified with respect to type (high- and low-risk) and the patient’s place in the treatment pathway (untreated, treated, and posttreatment).
The choice of medication may vary depending on differences in the case mix of patients, various drugs (of same or different class) listed in the formulary or clinical practice guidelines already in place at different institutions in similar patient care locations.
Timely use of diagnostic tests or documentation of symptoms supporting the presence of infection would be best. Cultures (two sets of blood cultures and other appropriate samples as clinically indicated e.g. normally sterile body fluids, deep pus etc.) should be taken before starting empiric antibiotic treatment.
Empiric antibiotic treatment for common infections should be limited to conditions where early initiation of antibiotics has been shown to be beneficial, e.g. severe sepsis and septic shock, acute bacterial meningitis, community acquired pneumonia, necrotizing fasciitis, etc.
Re-assessment of the situation within 48 hours based on the test results and examination of the patient is required. If needed, the drug’s dosage and duration can be adjusted or the antibiotic regimen should be de-escalated (to the narrowest spectrum, least toxic and least expensive antibiotic) based upon patient response and culture and susceptibility reports.
Common pathogens causing “tropical fevers”, “seasonal fevers” “endemic /epidemic /outbreak fever”, “monsoon fever”:
Suspect malaria in all cases of acute undifferentiated fever (there are no key differentiating features between this and other causes (see below). Despite historical claims, fever patterns are not especially helpful in establishing a specific diagnosis.
Malaria is especially to be suspected after a visit to high malaria endemic zone.
Viruses cause febrile illness or specific viral “influenza-like- illness” (with mild sore throat and cough).
If rash or exanthem is present without drug exposure (rule out drug allergy), consider mononucleosis syndrome (EBV, CMV, HIV) or an exanthematous viral illness (measles, rubella, etc). Primary or secondary dengue may be accompanied by maculo-papular rash or polyarthralgia. Tourniquet test may be inappropriate as a general discriminating test without hemorrhagic manifestations or the shock syndrome. Consider hemorrhagic fever with two or more hemorrhagic symptoms – hemorrhagic or purpuric rash, epistaxis, conjunctival haemorrhage, bleeding gums, bleeding at puncture sites, hematuria, hematemesis, hemoptysis, blood in the stool.
Scrub typhus or murine typhus may present with skin eschar, regional lymphadenopathy, and maculopapular rash.
Leptospirosis can present with conjunctival suffusion, muscle tenderness and jaundice (ask for flood water or sewage exposure).
Typhoid should be suspected in the presence of continuous fever, gastro intestinal symptoms and splenomegaly.
Community acquired secondary bacteremia: Primary source may be occult. In most instances, it is either from underlying pneumonia, intra-abdominal infection or urosepsis. Symptoms related to these systems may not be manifest, especially in the elderly.
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