How to Interpret Microbiology Results - Bacteriology
There are methods to systematically read chest X-rays and a similar approach should be taken to laboratory results. They are multipart results and reading them in isolation means you will misinterpret the significance of the result. In order to correctly interpret a bacteriology report all three parts (if given) need to be considered in this order:
• Appearance
- A description of the appearance of the sample e.g. purulent, blood stained, turbid, clear
- Is there evidence of inflammation or disease e.g. purulent, pus or liquid stool
- Is there evidence of contact with a non-sterile site or absence of disease e.g. salivary sputum, epithelial cells in urine, formed stool
• Microscopy
- A list of the different appearances of microorganism present e.g. the report states a Gram-positive coccus in chains seen on the Gram film
- Is it consistent with the diagnosis e.g. the patient has symptoms of cough, SOB and fever, a possible diagnosis is pneumonia and pneumonia can be caused by a Gram-positive coccus in chains
• Culture and sensitivity
- A list of the microorganisms, which have grown
- Is it consistent with the diagnosis e.g. Streptococcus pneumoniae is cultured from a patient with pneumonia
- A list of antibiotics used to treat the bacteria that was cultured; it is not usually necessary to give every sensitive antibiotic listed
- The list of antibiotics allows choices based around potential allergies to antibiotics
- You may have to use combinations of antibiotics to treat mixed infections e.g. Escherichia coli and Bacteroides sp. with Cefuroxime and Metronidazole
Occasionally other tests are performed and reported separately as they do not fit the usual sequence of Appearance, Microscopy and Culture. They are performed when the clinical details alert the laboratory to the need for further or specific testing.
• Antigen detection
- Clinical details state CAP e.g. the laboratory conducts the tests for urine Pneumococcal and Legionella antigens
- Clinical details state an outbreak of diarrhoea and vomiting e.g. the laboratory conducts the tests for Norovirus and Rotavirus in stool
• Molecular detection of nucleic acid or Polymerase Chain Reaction (PCR)
- Clinical details state meningitis e.g. the laboratory conducts the tests for Neisseria
meningitidis and Streptococcus pneumoniae PCR on EDTA blood
• Toxin detection
- Clinical details state diarrhoea after stating Ciprofloxacin e.g. the laboratory conducts the tests for Clostridium difficile toxin in stool
• Appearance
- A description of the appearance of the sample e.g. purulent, blood stained, turbid, clear
- Is there evidence of inflammation or disease e.g. purulent, pus or liquid stool
- Is there evidence of contact with a non-sterile site or absence of disease e.g. salivary sputum, epithelial cells in urine, formed stool
• Microscopy
- A list of the different appearances of microorganism present e.g. the report states a Gram-positive coccus in chains seen on the Gram film
- Is it consistent with the diagnosis e.g. the patient has symptoms of cough, SOB and fever, a possible diagnosis is pneumonia and pneumonia can be caused by a Gram-positive coccus in chains
• Culture and sensitivity
- A list of the microorganisms, which have grown
- Is it consistent with the diagnosis e.g. Streptococcus pneumoniae is cultured from a patient with pneumonia
- A list of antibiotics used to treat the bacteria that was cultured; it is not usually necessary to give every sensitive antibiotic listed
- The list of antibiotics allows choices based around potential allergies to antibiotics
- You may have to use combinations of antibiotics to treat mixed infections e.g. Escherichia coli and Bacteroides sp. with Cefuroxime and Metronidazole
Occasionally other tests are performed and reported separately as they do not fit the usual sequence of Appearance, Microscopy and Culture. They are performed when the clinical details alert the laboratory to the need for further or specific testing.
• Antigen detection
- Clinical details state CAP e.g. the laboratory conducts the tests for urine Pneumococcal and Legionella antigens
- Clinical details state an outbreak of diarrhoea and vomiting e.g. the laboratory conducts the tests for Norovirus and Rotavirus in stool
• Molecular detection of nucleic acid or Polymerase Chain Reaction (PCR)
- Clinical details state meningitis e.g. the laboratory conducts the tests for Neisseria
meningitidis and Streptococcus pneumoniae PCR on EDTA blood
• Toxin detection
- Clinical details state diarrhoea after stating Ciprofloxacin e.g. the laboratory conducts the tests for Clostridium difficile toxin in stool
Topics in Microbiology:
All these topics are covered in the book...Ready to buy your copy? Click here to buy your copy of "Microbiology Nuts & Bolts" Its updated and amazingly only slightly larger considering its got 1/3 more in it! (11cmx18cmx2.5cm).
- How to Take Microbiology Specimens
- Why Bother Completing Request Forms?
- What is Relevant Information for a Request Form?
- Considerations When Contacting a Microbiologist for Advice
- A to Z of Microbiology Tests by Microorganism or Condition
- A to Z of Microbiology Tests by Specimen Type
- Microbiology Results (by Specimen Type)
- How to Interpret Microbiology Results - Bacteriology
- Examples of Bacteriology Requests, Results and Interpretations
- Why Can’t I Do Every Test?
- Examples of Pre and Post-test Probability Results and Interpretations
- How to Use Pre-test Probability, Likelihood Ratios and Post-test Probabilities in the Clinical Setting
- Basic Bacterial Identification by Microscopy
- Basic Bacterial Identification
- Table of Bacterial Causes of Infection
- How to Interpret Microbiology Results – Serology and Virology
- Examples of Serology / Virology Requests, Results and Interpretations
- Notifiable Infectious Diseases in the UK
All these topics are covered in the book...Ready to buy your copy? Click here to buy your copy of "Microbiology Nuts & Bolts" Its updated and amazingly only slightly larger considering its got 1/3 more in it! (11cmx18cmx2.5cm).
