2.G8

What is meant by a nosocomial infection? Give its acronym.

An infection acquired as a result of healthcare, occurring due to time in hospitals, clinics, or community care settings: healthcare-associated infection (HCAI)

Give four common examples of nosocomial pathogens.

• MRSA

• Clostridium difficile

• Glycopeptide-resistant enterococci (GRE)

• Acinetobacter spp.

List five key risk factors for acquiring an HCAI.

1. High numbers of susceptible patients being treated (e.g. elderly, chronically ill);

2. Invasive procedures/indwelling devices

3. Immunosuppression (e.g. chemotherapy)

4. Increased patient movement between wards/hospitals (bed management pressure)

5. Wide use of antibiotics with emergence of resistant microorganisms.

Higher rates of HCAIs are often found where?

• Specialist hospitals: orthopaedic centres

• Minor surgery in the community, HCAIs may become more common

Which single prevention activity is considered most important for nosocomial/HCAI control? Give an example of a public campaign.

• Proper hand-washing by staff, patients and visitors.

• ‘Hands. Face. Space’ and singing Happy Birthday - COVID-19

Give 5 control measures to reduce the incidence of HCAIs, including the prevention activity considered most important.

• Hand washing is generally the most impor- tant prevention activity. For example, in the United Kingdom, the ‘clean your hands’ cam- paign raised awareness among staff, patients, and the public.

• Universal precautions.

• Prudent antibiotic prescribing.

• Surveillance (e.g. the UK surveillance sys- tems for MRSA, surgical site infection).

• Isolation

Name the four groups identified as having increased risk of spreading gastrointestinal infection.

• People with doubtful personal hygiene or inadequate toileting facilities

• Children attending preschools or nurseries

• Food preparers or servers of unwrapped foods not reheated

• Clinical/social care staff with highly susceptible patients.

What are the classic clinical signs of diphtheria?

Acute upper-respiratory infection with enlarged lymph nodes and “bull-neck,” possible airway obstruction, paralysis, and cardiac failure.

Which laboratory test rapidly confirms toxigenic Corynebacterium diphtheriae infection?

Polymerase chain reaction (PCR) for the diphtheria toxin gene.

How is pertussis primarily prevented in infants in the UK?

By acellular pertussis vaccine as part of the DTaP/IPV/Hib schedule at 2, 3 and 4 months, plus preschool booster.

Why are pregnant women vaccinated against pertussis from 28 weeks’ gestation?

To transfer maternal antibodies to the newborn and reduce exposure to infectious contacts.

Which organism causes tetanus and where are its spores commonly found?

Clostridium tetani; spores are present in soil contaminated with animal faeces.

What is the routine UK immunisation schedule for tetanus?

Three doses at 2, 3 and 4 months, with boosters at 3–5 years and 13–18 years.

Which poliovirus serogroup is most virulent?

Serogroup type 2.

Why do many countries that have eradicated poliomyelitis switch to inactivated vaccine?

To avoid vaccine-associated paralytic polio that can occur with oral polio vaccine.

What is the most common presentation of invasive Haemophilus influenzae type b infection?

Meningitis in infants and young children.

Which two pneumococcal vaccines are routinely used in the UK and for whom?

PCV (7-valent) for children; PPV (23-valent) for all adults ≥65 years.

Which meningococcal serogroup vaccine was added to the UK infant schedule in 2014?

Meningococcal group B vaccine (Men B).

For whom is BCG vaccination recommended in the UK?

Infants in areas with TB incidence ≥40/100,000, infants with parents/grandparents from high-incidence countries, and previously unvaccinated new immigrants from high-prevalence regions.

Name three classic complications of mumps infection.

Meningitis, orchitis, and pancreatitis.

Which oral sign is pathognomonic for measles?

Koplik’s spots on the buccal mucosa.

What public-health measure should follow exposure of a non-immune pregnant woman to rubella?

Serological testing and, if susceptible, offer postpartum vaccination; immunoglobulin is not protective for the fetus.

Which four HPV types are targeted by the UK’s routine quadrivalent vaccine?

Types 16, 18, 6 and 11.

State two major impacts of HCAIs on patients.

Prolonged hospital stay and increased morbidity or death.

Which two MRSA strains dominate in the UK?

EMRSA-15 and EMRSA-16.

What stool assay confirms Clostridium difficile infection?

Detection of C. difficile toxin in stool.

Why are Campylobacter infections most commonly linked to poultry?

The bacterium colonises the gastrointestinal tract of birds, and under-cooked poultry transmits infection.

Which simple public-health rule is advised to travellers to cholera-endemic areas?

“Boil it, cook it, peel it, or forget it.”

What is the main reservoir of Cryptosporidium parvum?

Gastrointestinal tracts of humans and farm/domestic animals, contaminating water.

Which Shigella species is associated with severe disease and exotoxin production?

Shigella dysenteriae type 1.

Give two serious complications of E. coli O157 infection.

Haemolytic–uraemic syndrome (HUS) and death.

Name two common Salmonella serotypes of public-health concern in the UK and their typical sources.

S. enteritidis PT4 (eggs/poultry) and S. typhimurium DT104 (antibiotic-resistant, various animals).

Which organism causes enteric fever and is most often acquired where by UK travellers?

Salmonella Typhi or Paratyphi, typically acquired in South Asia and Africa.

What is the usual exclusion period from work/school after norovirus symptoms resolve?

At least 48 hours after symptoms have stopped.

How is acute hepatitis A best prevented among household contacts of a case?

Offer immunoglobulin or hepatitis A vaccine promptly.

Which hepatitis virus is most commonly transmitted perinatally in high-prevalence countries?

Hepatitis B virus (HBV).

What do the following HBV markers indicate: HBsAg positive for >6 months?

Chronic carrier; the person remains infectious.

Which HBV serological marker signifies immunity due to past infection or vaccination?

Anti-HBs antibody.

What does IgM anti-HBc positivity suggest?

Acute or recent hepatitis B infection.

What is the most important risk factor for hepatitis C transmission in the UK today?

Sharing needles among intravenous drug users.

Which two drugs form the backbone of treatment for chronic hepatitis C infection?

Interferon and ribavirin.

Which influenza type causes most severe epidemics in humans?

Influenza type A.

What three components underpin the ‘ABC D’ malaria travel advice?

Awareness of risk, Bite prevention, Chemoprophylaxis, early Diagnosis.

How is Legionella pneumophila most commonly transmitted?

Inhalation of contaminated water aerosols from cooling towers, air-conditioning units, or spas.

Which bacterial STI is the commonest in the UK and why is screening important?

Chlamydia trachomatis; many infections are asymptomatic but can cause PID and infertility.

What programme monitors antibiotic resistance in Neisseria gonorrhoeae in England?

GRASP – Gonococcal Resistance to Antimicrobials Surveillance Programme.

Which two serological tests are used for syphilis diagnosis and what do they detect?

Treponemal tests (e.g. TPHA) detect antibodies to T. pallidum; non-treponemal tests (e.g. VDRL) detect reagin antibodies and monitor disease activity.

What main strategy reduces mother-to-child transmission of HIV in the UK?

Routine antenatal HIV screening and antiretroviral therapy for positive mothers.

Which mosquito genus transmits dengue fever?

Aedes mosquitoes, particularly Aedes aegypti.

What characteristic early rash helps diagnose Lyme disease?

Erythema migrans – an expanding “bull’s-eye” rash at the tick bite site.

List four key drivers of emerging infectious diseases.

Global travel, climate change, antimicrobial resistance, and genetic mutation/recombination (other acceptable: urbanisation, deforestation, animal movements, etc.).

Name three infectious agents currently attracting special health-protection attention.

Smallpox (bioterror concern), SARS-CoV, and avian influenza (e.g. H5N1).

Which zoonotic infection, important in Australia/New Zealand, follows exposure to animal urine-contaminated water?

Leptospirosis (Weil’s disease).

What chronic cardiac condition may follow acute rheumatic fever in indigenous populations of NZ and Australia?

Chronic rheumatic heart disease from valvular damage.

Which occupationally acquired infection is prevented by Q-fever vaccination for at-risk Australian farm workers?

Coxiella burnetii infection (Q fever).

Why did variant CJD emerge in the UK in the 1990s?

Consumption of beef from cattle infected with bovine spongiform encephalopathy (BSE).

What treatment is recommended for scabies cases and their close contacts?

Topical permethrin (or malathion) applied to skin, plus washing of clothes and bedding.

Which two epidemics place the greatest communicable-disease burden on South Africa?

HIV infection and tuberculosis (including MDR-TB and XDR-TB).

Which zoonotic disease remains a risk in rural Africa due to low vaccination of dogs?

Rabies.

What laboratory test is most sensitive for early diagnosis of malaria?

Microscopy of a thick/thin blood smear or rapid antigen test (RDT); PCR is highly sensitive but less available.