Microbiology deals with diseases caused by infectious agents (known as pathogens) such as bacteria, viruses, fungi and parasites. Microbiologists can have roles in both the laboratory and direct patient care.

The specimens examined in microbiology departments are varied and include body fluids such as sputum and urine as well as blood.

Microbiologists play an important part in infection control and public health, for example with epidemics such as influenza. They are also at the forefront of tackling antibiotic resistance and new infectious diseases.

Dr Petra Derrington told us about her role as a microbiologist.

1. What made you decide to specialise in microbiology?
I decided to do microbiology when I was only 14. We did biology of micro-organisms at school and I was fascinated, particularly by their ability to do so much with so little inside their nuclei. I was also fascinated by the association between viruses and cancer.

I was advised that doing medicine and specialising in microbiology was a good career move and I chose this route instead of doing a laboratory degree. I tried to get as wide an experience as possible in medicine for a few years after I qualified, before specialising in microbiology, to ensure I had a good wide overall experience but specialising in microbiology was always going to be the final goal.

2. How many hours do you now work in a typical week?
I generally do about 45 hours at work, but spend many hours a week on my computer at night catching up. I am also on call 24/7 for clinical queries. In addition, I validate and call out significant cultures every weekend and holiday to ensure a smooth continuity of service.

3. What does a typical day involve?
At present, I have a Director of Pathology and a microbiologist role. My microbiologist role is simple, I validate all the positive results, go through my review list and call out all new blood cultures and important positive cultures. I take many calls throughout the day for advice on therapy, interpretation and diagnostics. I also work closely with the Infection Control department and the Infectious Diseases team and we have a combined daily plate round where we discuss interesting and important cultures and antibiotic stewardship. I also do a lot of teaching of students and peers, audits and some low key research in the laboratory.

The director role is a lot more demanding. I need to manage all the quality outputs of the laboratory as well as ensure our relationship with clients is maintained. I am responsible for ensuring our strategic direction is being followed and that we have adequate staffing and resources for this. I am involved in managing any complaints and need to support our staff to improve practice.

4. What makes your job enjoyable and satisfying?
As a microbiologist, I deal with the results of patients from every speciality so I can get calls from paediatrics to orthopaedics and everything in between. When the phone rings, it can be anything at all coming in from any area and I find that challenging. I never stop learning and bacteria and viruses are always changing and doing new and interesting thing to keep me on my toes. The more I learn, the more fascinated I become. This speciality is moving ahead so very quickly in all areas of diagnostics, and keeping ahead of this is very challenging.

As Director of Pathology, I have responsibility to ensure that our laboratory is functioning in the most efficient way, that we have happy and healthy staff who feel supported, empowered and vital, and that our clients get the best service. I need to ensure my leadership is trusted and supported. It is such an honour to have this job.

5. What are the most common conditions that you deal with?
I mostly deal with urosepsis, (an infection in the urinary tract that spreads to the bloodstream) skin and soft tissue infections, chest and gastrointestinal infections from the community, and various hospital acquired infections. We have large intensive care, renal, haematology/oncology, respiratory and orthopaedic services, and I assist with the many complex and chronic infections.

6. What is the rarest or most unusual condition you have come across?
We recently saw a young boy with chronic Q fever* presenting as a multifocal osteomyelitis**. The condition itself is not very common and is not usually seen in children.

*Q fever is a bacterial infection caused by the bacteria Coxiella burnetii and is usually spread from animals such as cattle and sheep. Spread from person to person is rare and the disease usually occurs in people working with the animals who may breathe in dust particles contaminated with the bacteria. If a chronic case develops this can lead to serious complications such as inflammation of the heart valves but the infection can be treated with antibiotics once diagnosed.

**Multifocal osteomyelitis is an infection of the bone in several places in the body.