Lecture 10. Nosocomial and Community Infections Flashcards
What are nosocomial or healthcare associated infections (HCAI)?
Defined as an infection developing in a patient as a result of healthcare contact, and had no signs of infection within first 48 hrs of admission
What are non-nosocomial or community acquired infections (CAI)
Defined as an infection acquired outside the healthcare setting. When in hospital this includes infections diagnosed within 48 hours of admission
What percentage of hospitalised patients in developed countries acquire a HCAI?
7%
What percentage of hospitalised patients in developing countries acquire a HCAI?
10%
What are the 5 main types of nosocomial infections?
Central line associated bloodstream infections
Catheter associated urinary tract infections (UTI)
Nosocomial pneumonia – inc. ventilator associated pneumonia (VAP) - Covid-19
Surgical site infections (SSI)
Gastrointestinal infection
What are examples of nosocomial bacterial pathogens?
- Pseudomonas aeruginosa
- Staphylococcus aureus (MRSA)
- Klebsiella spp.
- Enterococcus spp.
- Escherichia coli
- Clostridium difficile
What are examples of nosocomial viral pathogens?
Covid-19 and Norovirus
What are the environmental risk factors for nosocomial infections?
Poor hygienic conditions and inadequate waste disposal from health care settings
Covid - Building design, ventilation, overcrowding, short staffed and overwhelmed clinical teams, and a lack of testing and PPE in those early months
What are the risk factors for nosocomial infections associated with susceptibility?
Immunosuppression, underlying health, age, use of medical devices, drug treatment, pain management, length of stay etc
What are the risk factors for nosocomial infections associated with unawareness?
Improper use of injection techniques, poor knowledge of basic infection control measures, inappropriate use of invasive devices (catheters) and lack of control policies
What are the goals of the Health Security Agency (HSA)?
Management of HCAI (preventing and reducing rates of HCAI and infection prevention and control, using evidence-based interventions)
Surveillance programmes are an important part of this, as they provide essential information on what and where the problems are and how well control measures are working
What is clostridium difficile responsible for?
A variety of gastrointestinal manifestations ranging from asymptomatic carriage to mild diarrhoea, pseudomembranous colitis, and, very rarely bowel perforation and death
How is clostridium difficile transmitted?
Faeco-oral
What are the risk factors for clostridium difficile infections (CDI)?
Antibiotics (significant risk: fluoroquinalones & cephalosporins, no associated risk: tetracyclins)
Gastric acid suppressants (proton pump inhibitors (PPIs) appear to be associated and links to disruption of microbiota (dysbiosis))
Co-morbidities (strong link to inflammatory bowel disease (IBD) and other associations with chronic kidney disease, immunodeficiency and solid organ transplants)
How can C. diff be treated and controlled?
Diagnosis
Specific antibiotic treatment
Isolation
Hand hygiene
PPE – gloves and apron
Bleach cleaning
How can C. diff be prevented?
Hygiene
Appropriate use of antibiotics to reduce risk in first place
What are the two common species of Klebsiella spp. associated with the majority of human infections?
Klebsiella pneumoniae and Klebsiella oxytoca
How is Klebsiella spp. transmitted?
Transmission, complex and not fully understood
Person-to-person contact or, less commonly, by contamination of the environment
Patients may be exposed to Klebsiella when they are on ventilators, or have intravenous catheters or wounds (caused by injury or surgery)
What is the mortality rate of Klebsiella pneumoniae?
High mortality rate if invades the blood - 50% even with treatment
What are the clinical features of Klebsiella pneumoniae?
High fever, pleuritic chest pain, ‘currant jelly’ sputum
Leukopenia can occur
What therapies are there to treat Klebsiella pneumoniae?
Antibiotics (some strains are antibiotic resistant) e.g. Carbapenems (where there is no resistance)
What is the epidemiology of Klebsiella pneumoniae?
Ubiquitous in nature: surface water, sewage, and soil
Carriers; in stool samples ranges from 5 to 38%; in nasopharynx 1 to 6%
What are many HCAIs?
AMR
What are community acquired CDIs (CA-CDI)?
Emergence of disease in the community over the last 20 years
Risk factors as before
Routes of transmission, included
human, animal, food and environmental sources
How are CA-CDIs transmitted by human contacts?
Potential in children under 2 years of age and their primary carers
The role of asymptomatic carriers is not well established
How are CA-CDIs transmitted by food?
Undoubtedly exists, but mostly presumptuous
Retail meats
How are CA-CDIs transmitted by animals?
Farmed animals
Some reports of outbreaks in veterinary hospitals
Animal-human or human-animal transmission is biologically plausible
How are CA-CDIs transmitted by the environment?
Soil bacteria, contamination of dwellings
Spores residing in kitchens from raw meat
What are the mortality risk factors of Covid?
Age, obesity, underlying health conditions
What are the infection and mortality risk factors of Streptococcus pneumonia?
Age and gender
How many different strains of Streptococcus pneumoniae are there?
More than 90
What does Streptococcus pneumoniae cause?
Both invasive and non-invasive pneumococcal infections
What are examples of non-invasive pneumococcal infections?
Bronchitis, Otis media, sinusitis
What are examples of invasive pneumococcal infections?
Bacteraemia, septicaemia, osteomyelitis, meningitis & pneumonia
Is multi drug resistant Streptococcus pneumoniae a concern?
It is, but reduced due to recent vaccination programmes
