Modifying empirical therapy for bloodstream infections when the pathogen is identified
Modify antimicrobial therapy for bloodstream infections, including sepsis or septic shock, as soon as additional information is available (eg source of infection, Gram stain, results of culture and susceptibility testing). If a pathogen has been identified and is consistent with the source of infection, de-escalate treatment according to the following pathogen-specific recommendations. However, in some cases (eg intra-abdominal sepsis associated with a perforated viscus) it is appropriate to continue empirical therapy targeted to the source of infection. Occasionally, an organism identified by culture (eg a coagulase-negative staphylococcus) is a contaminant. A clinical microbiologist or infectious diseases physician can assist with modifying therapy based on microbiological results and clinical progress.
Advice on directed therapy for bloodstream infections, including sepsis and septic shock, is included in these guidelines for the following pathogens:
- Candidaemia (including Candida and related species sepsis)
- Enterobacterales (including E. coli and K. pneumoniae) bloodstream infections, including sepsis and septic shock
- Pseudomonas aeruginosa bloodstream infections, including sepsis and septic shock
- Staphylococcus aureus bacteraemia, including sepsis and septic shock
- Streptococcus agalactiae (group B streptococcus) bloodstream infections, including sepsis and septic shock
- Streptococcus pneumoniae (pneumococcal) bloodstream infections, including sepsis and septic shock
- Streptococcus pyogenes (group A streptococcus) bloodstream infections, including sepsis, septic shock and toxic shock syndrome
- Typhoid and paratyphoid fevers (Salmonella Typhi and Paratyphi A, B and C infection).
Regimens for bacteraemia, including sepsis and septic shock, caused by enterococci, Clostridium species, Listeria monocytogenes and Neisseria meningitidis are not included in these guidelines. For drug choice, see:
- Enterococcal endocarditis for bacteraemia caused by enterococci
- Clostridial necrotising skin and soft tissue infection for bacteraemia caused by Clostridium species
- Listeria monocytogenes meningoencephalitis for bacteraemia caused by L. monocytogenes
- Neisseria meningitidis (meningococcal) sepsis for bacteraemia caused by N. meningitidis.
In neonates, the choice of antimicrobials for directed therapy of bloodstream infections, including sepsis and septic shock is complex – seek expert advice. A regimen based on local protocols, or advice from a clinical microbiologist or infectious diseases physician improves outcomes. This is particularly important for neonates in the intensive care unit. Mortality is decreased when appropriate antibiotics are given early. Pathogen-specific regimens are included in these guidelines for: