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Clinical Microbiology

The Microbiology service is a comprehensive, clinically-led service provided for Bacteriology, Infectious Serology (including Molecular services), Mycology and Parasitology testing.

We offer clinical advice for Infection Prevention and Control and we have access to a wide range of reference facilities for specialist and confirmatory testing.

Opening times

Monday to Sunday: 8:45am to 9pm

  • Please note – from 5:15pm to 9pm essential work only
  • On weekends there is no Virology service

Out of hours

Urgent work will be processed at any time. There are provisions for Consultant cover out of hours within CMB. Advice from a consultant Microbiologist is available via switchboard. Process of urgent samples can be arranged by contacting the on-call biomedical scientist via switchboard (01872 250000).


This service performs a wide range of testing for infectious diseases, including:

  • Blood cultures
  • Faeces (including Parasitology)
  • Urines
  • CSF
  • Swabs
  • Lower and upper respiratory tract
  • Mycobacteria (TB)
  • Mycology samples for fungal infection
  • Routine screening (MRSA)

Infectious Serology & Molecular

This section provides specialist testing in the following areas:

  • Infectious serology (including HIV, Syphilis, Hepatitis, Helicobacter pylori)
  • Molecular (including Chlamydia, Gonorrhoeae, Norovirus, Respiratory)
  • Routine screening (Antenatal)
  • HPV testing for patients from Cornwall and Plymouth (in conjunction with Cytology)

Antimicrobial Susceptibility Testing

Effective use of antimicrobials (including antibiotics) is vital to help prevent and slow the development of resistance and make sure that antimicrobials remain effective in treating infection. RCHT’s intranet Clinical Shelf (only works if you are connected to the internal network) provides:

  • Recommendation for prescription of empirical antimicrobials for adults for the treatment of infections, based on the likely causative organisms in each specific condition.
  • Recommendation for antimicrobial prophylaxis in surgery.
  • Good practice points with respect to antimicrobial prescribing.

Alerts for previous resistant organisms (such as ESBL/MRSA) should be checked on MAXIMS and empirical antibiotics modified accordingly to cover them until culture results become available. Antimicrobial treatment must be reviewed with positive cultures wherever applicable and must comply with the Trust Antimicrobial Guideline.

Definitions of susceptibility testing categories S, I and R have recently been changed by EUCAST (European Committee on Antimicrobial Susceptibility Testing) as shown below.

S Susceptible, standard dosing regimen: A microorganism is categorised as “Susceptible, standard dosing regimen”, when there is a high likelihood of therapeutic success using a standard dosing regimen of the agent.
I Susceptible, increased exposure*: A microorganism is categorised as “Susceptible, Increased exposure*” when there is a high likelihood of therapeutic success because exposure to the agent is increased by adjusting the dosing regimen or by its concentration at the site of infection.
R Resistant: A microorganism is categorised as “Resistant” when there is a high likelihood of therapeutic failure even when there is increased exposure.

*Exposure is a function of how the mode of administration, dose, dosing interval, infusion time, as well as distribution and excretion of the antimicrobial agent will influence the infecting organism at the site of infection.

Further links and information

Departments in our service