Special Precautions/Comments:

N.B. Collect specimens before antimicrobial therapy where possible.

Interferences:  Antibiotics may affect growth of certain bacteria.

Method:  Blood culture bottles are continuously monitored for predefined number of days by the  BacT/ALERT 3D automated blood culture system. Any positive culture bottles are subjected to microscopic examination, subculture and appropriate susceptibility testing. Calibration: BacT/ALERT 3D automated blood culture system calibrators supplied by bioMérieux. EQA scheme: UKNEQAS General Bacteriology scheme (culture and identification). Lab Quality (gram stains). BMS MICRO EQA (whole workflow process). IQC: In-house preparations (gram stains).

Interpretation: All positive results will be interpreted by the Consultant Microbiologist. This includes gram stain, isolate(s) and sensitivity test results. Clinical comments will be provided based on patient history.

Neisseria meningitidis, Streptococcus pyogenes, Streptococcus pneumoniae and Haemophilus influenzae isolates are routinely sent for typing to PHE. Other isolates may be sent for typing at discretion of Microbiologist, e.g Staph aureus for WGS and HG3 isolates for confirmation of identification.

Additional Information:

Background information: Blood culture is considered to be the “gold standard” investigation for the detection of micro-organisms in blood. The culture of micro-organisms from blood is essential for microbiological diagnosis of bacteraemia, fungaemia, infective endocarditis and conditions associated with a clinical presentation of pyrexia of unknown origin (PUO).  Blood culture is also important for the diagnosis of prosthetic device infections (eg joints and vascular grafts) and intravascular line-associated sepsis. Blood cultures may also detect bloodstream infections associated with other conditions such as pneumonia, septic arthritis and osteomyelitis. Antibiotic resistance amongst pathogens (particularly Gram negative bacteria) is the most frequent cause of ineffective empirical treatment in bloodstream infection. Early identification and antibiotic susceptibility results for blood culture isolates provide valuable diagnostic information on which appropriate antimicrobial therapy can be based, so helping to reduce morbidity and mortality, improve patient care and reduce healthcare costs. Decreasing turnaround times (TAT) at each stage of the process from transportation of samples to reporting of results is therefore recommended.