An infectious disease diagnosis for antibiotic or antimicrobial therapy is reached by determining the site of infection, defining the condition of the host, and establishing when possible a microbiological diagnosis.
The initiation of antimicrobial therapy is urgent in patients with serious acute bacterial infections.
Initiation of therapy is often recommended within an hour after presentation, despite the diagnostic uncertainty during the first few days of treatment, especially regarding the identification of the infecting pathogen and its antimicrobial susceptibility.
Initial empirical treatment may be necessary for effective management of an infection.
In serious and life-threatening infections isolating the specific pathogen is essential.
Antibiotic therapy initiation is guided by the urgency of the clinical situation.
Antibiotic therapy should be initiated immediately in critically ill patients such as those with neutropenic fever, septic shock, bacterial meningitis.
Antibiotic therapy in critically ill patients should be initiated immediately after or concurrently with collection of diagnostic specimens.
Antimicrobial therapy can be withheld in stable clinical conditions until appropriate specimens have been collected and submitted for microbiological evaluation.
Prolonged antibiotic exposure provokes resistance and increases the occurrence of adverse effects such as Clostridium difficile infection and other microbiotic disruptions.
Prolonged courses of antibiotics are associated with longer hospitalizations and higher costs, Gram negative bacteremia, particularly due to E. coli, a frequent community acquired and healthcare associated infection.
In patients with suspected subacute bacterial endocarditis or vertebral osteomyelitis/diskitis should have delayed antibiotic treatment until multiple sets of blood cultures or disk space aspirate or bone biopsy specimens have been obtained.
Premature administration of antimicrobials can often suppress bacterial growth and prevent the establishment of a microbiological diagnosis critically needed, in the management of these patients, to achieve cure.
Antibiotics should not be used for apparent viral respiratory illnesses (sinusitis, pharyngitis, bronchitis and bronchiolitis).
Antibiotic use for asthma exacerbation does not improve outcomes.
Antibiotics are frequently used ufor acute bronchitis inappropriately, and 76% of visits to the physician’s office for bronchitis result in an antibiotic prescription.
Cultured specimens should be properly obtained and submitted before institution of antimicrobial therapy.
Exposure history is essential as the most likely microbiological diagnosis can be inferred from clinical presentation.
Approximately half of antibiotic use is inappropriate being generally used for viral conditions that do not respond to antibiotics.
In the outpatient setting at least one third of all antibiotics are prescribed unnecessarily.
Initial therapy for infection is frequently empiric and guided by clinical presentation, as microbiological information does not become available for 24 to 72 hours.
Because inadequate antibiotic therapy for infections in critically ill hospitalized patients is associated with poor outcomes commonly broad spectrum antimicrobial agents are initial empiric therapy.
The intent of empirical antibiotic therapy is to cover multiple possible that the genes commonly associated with the clinical process.
Empiric therapy for a young adult with suspected bacterial meningitis would be a combination of a third-generation cephalosporin, such as ceftriaxone, plus vancomycin since the most likely pathogens are Streptococcus pneumoniae and Neisseria meningitidis.
Empiric antibiotic therapy for hospital acquired infections should be based on the site of infection and the organisms most likely to colonize that site, prior knowledge of bacteria known to colonize a given patient, and local bacterial resistance patterns of the hospital.
Bactericidal agents cause death and disruption of the bacterial cell, including action on cell wall, cell membrane or bacterial DNA.
Bacteriostatic agents include sulfonamides, tetracyclines, and macrolides , act by inhibiting protein synthesis.
Bactericidal agents are preferred in serious infections to achieve rapid cure.
When microbiological identification of a pathogen is made and antimicrobial susceptibility studies are available the spectrum of the antibiotics should be narrowed to reduced cost, toxicity, and the emergence of antimicrobial resistance.
Single agent antibiotic is preferred management in most infections.
Combination of antibiotics with synergistic effect may be used in a variety of gram positive and gram negative infections of serious nature when rapid killing is essential such as Enterococcus endocarditis or streptococci viridans endocarditis.
Combination empirical antibiotics indicated for health care associated infections in critically ill patients when antimicrobial resistance is expected, and microbiological etiology or sensitivity studies are pending.
Empirical combination antibiotics indicated when infections are thought to be caused by more than one organism and the microbiological spectrum needs to be extended.
Overuse of antibiotics leads to the development of bacterial resistance and increases susceptibility to Clostridium difficile another serious infections.
55.7% of patients receive antibiotics in a study of 323 hospitals in the US (Fridkin S et al).
Antibiotics have the potential to harm other individuals by the spread of C. Difficile and the development of antimicrobial resistance.
Prescribing antibiotics requires the weighing of the potential benefit to the patient against the potential harm to society.
The most commonly prescribed antibiotic for adults is azithromycin, despite this drug being recommended as the first line choice for very few conditions.
Antibiotic usage in US hospitals has been stable, but the use of broad-spectrum anabiotics has increased significantly (Baggs J).
Hospitals have 755 days of antibiotic therapy per 1000 patient days.
Antibiotics decrease the diversity of gut bacteria, which, in turn, can cause less efficient nutrient extraction, as well as a vulnerability to enteric infections.
Bacterial gut microbiome can either inhibit or promote diarrheal illnesses such as those caused by C. difficile.
C. difficile infection (CDI) is the most common health care-related infection.
C. difficile infection (CDI) accounts for approximately a half million health care facility infections a year.
CDI extends hospital stays an average of almost 10 days and is estimated to cost the health care system $6.3 billion annually.
Antibiotics can eliminate antibiotic-susceptible organisms, allowing resistant organisms to proliferate.
Promote the transmission of genes for antibiotic resistance between gut bacteria.
Preservation of Lactobacillus populations in the gut is associated with markers predictive of better HIV outcomes, including a higher CD4 count, a lower viral load, and less evidence of gut microbial translocation.
It is important to maintain a healthy gut flora in patients with HIV, using such steps as avoiding unnecessary antibiotics.
Gut microbiome is involved in 2-way communication with the brain and can affect, and be affected by, stress and depression.
A disordered microbiome is associated with depression, anxiety, Crohn’s disease, type 2 diabetes, and obesity.
Repeated use of broad spectrum antibiotics in children <24 months of age increases the risk of developing childhood obesity.
The association of broad-spectrum antibiotics effects on the intestinal flora of young children may alter long-term energy homeostasis resulting in a higher risk for obesity.
Antibiotics over prescribed: patient demand, pharmaceutical company marketing, limited up-to-date information sources, and physician fear of losing their patients are major reasons.