The current NICE guidelines for hospital-acquired pneumonia are as follow:- First-choice oral antibiotic if non‑severe symptoms or signs, and not at higher risk of resistance (guided by microbiological results when available): co-amoxiclav- Alternative oral antibiotics if non‑severe symptoms or signs, and not at higher risk of resistance, for penicillin allergy or if co‑amoxiclav unsuitable (based on specialist microbiological advice and local resistance data): doxycycline, cefalexin, co-trimoxazole, levofloxacin- First-choice intravenous antibiotics if severe symptoms or signs (for example, symptoms or signs of sepsis) or at higher risk of resistance (based on specialist microbiological advice and local resistance data): piperacillin with tazobactam, ceftazidime, ceftriaxone, cefuroxime, meropenem, ceftazidime with avibactam, levofloxacin- Antibiotics to be added if suspected or confirmed methicillin-resistant Staphylococcus aureus infection (dual therapy with a first-choice intravenous antibiotic): vancomycin, teicoplanin, linezolid

Nosocomial infections are defined as those occurring within 48 hours of hospital admission, 3 days of discharge or 30 days of an operation. They affect 1 in 10 patients admitted to hospital. Annually, this results in 5000 deaths with a cost to the National Health Service of a billion pounds. On average, a patient with hospital acquired infection spent 2.5-times longer in hospital, incurring additional costs of £3000 more than an uninfected patient. Intensive care units (ICU) have the highest prevalence of hospital-acquired infections in the hospital setting.The current recommendations by NICE and the BNF on the treatment of hospital acquired pneumonia are:Early onset infection(less than 5 days after admission to hospital): co-amoxiclav or cefuroxime for 7 daysLate-onset infection(more than 5 days after admission to hospital): an antipseudomonal penicillin (e.g. piperacillin with tazobactam), a broad-spectrum cephalosporin (e.g. ceftazidime), or a quinolone (e.g. ciprofloxacin)If the patient developed a hospital-acquired pneumonia within 5 days of admission – co-amoxiclav would be the most appropriate choice.If the patient has developed a hospital-acquired pneumonia > 5 days after admission – ciprofloxacin would be the most appropriate choice from the list of options available.

Hepatitis B vaccine should be stored at 35°-46° F (2°-8° C) and should not be frozen.There is no association between hepatitis B vaccination and Guillain-Barre syndrome. Infection with the bacterium Campylobacter jejuni is one of the most common risk factors for GBS. People can also develop GBS after having the flu or other infections (such as cytomegalovirus and Epstein Barr virus).Hepatitis B vaccine is prepared from initial concentration of surface antigen.To ensure adequate immunity, anti-HBs (HBsAb) titres may be checked 4-8 weeks following the last shot of the hepatitis B vaccine series.

The options listed in this question are not true contraindications to vaccination. Therefore, the correct answer is ‘none of the other options’.The contraindications to vaccination are:Confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.A confirmed anaphylactic reaction to another component in the vaccine.

The following is the list of all the health and age factors that are known to increase a person’s risk of getting serious complications from flu:- Adults 65 years and older- Children younger than 2 years old- Asthma- Neurological and neurodevelopmental conditions- Blood disorders (such as sickle cell disease)- Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)- Endocrine disorders (such as diabetes mellitus)- Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)- Kidney diseases- Liver disorders- Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)- People who are obese with a body mass index [BMI] of 40 or higher- People younger than 19 years old on long-term aspirin- or salicylate-containing medications.- People with a weakened immune system due to disease (such as people with HIV or AIDS, or some cancers such as leukaemia) or medications (such as those receiving chemotherapy or radiation treatment for cancer, or persons with chronic conditions requiring chronic corticosteroids or other drugs that suppress the immune system)- People who have had a stroke- Pregnant people and people up to 2 weeks after the end of pregnancy- People who live in nursing homes and other long-term care facilities

Facultative anaerobic bacteria make energy in the form of ATP by aerobic respiration in an oxygen rich environment and can switch to fermentation in an oxygen poor environment.Examples of facultative anaerobes are:Staphylococcus spp.Listeria spp.Streptococcus spp.Escherichia coliMycobacterium tuberculosis, and Pseudomonas aeruginosa are obligate aerobe. They require oxygen to growCampylobacter jejuni and Clostridium spp are obligate anaerobes.They live and grow in the absence of oxygen.

Droplets are airborne particles greater than 5 µm in size. Droplet transmission occurs during talking, coughing and sneezing where respiratory droplets are generated.Examples of organisms transmitted by the droplet route include:Neisseria meningitidisRespiratory syncytial virusParainfluenza virusBordetella pertussisInfluenza virusPoliovirus and Rotavirus are transmitted by the faeco-oral routeHepatitis B is transmitted by Sexual routeStaphylococcus aureus is transmitted by direct contact

Impetigo is a common pyoderma that is most often seen in children. Historically, most cases were caused by group A streptococci (GAS; Streptococcus pyogenes), although S. aureus has become the predominant pathogen over the last 15 years.A bullous form of impetigo accounts for approximately 10% of cases. It is caused by strains of S. aureus that produce exfoliative toxins leading to the formation of bullae, which quickly rupture and form a transparent, light brown crust.Impetigo is spread mainly by person-to-person contact; it is rapidly spread through direct transmission. The diagnosis of impetigo can be made from a Gram stain and culture of the vesicular contents.

The current recommendation by NICE and the BNF is to use vancomycin as first-line in treatment of septicaemia related to vascular catheter. A broad-spectrum antipseudomonal beta-lactam antibiotic should be added to vancomycin if a Gram-negative sepsis is suspected especially in an immunocompromised patient.In any patient that has had a central venous catheter in situ for a period longer than a week, it should be suspected as the source of sepsis.The features suggesting the vascular catheter as the source of infection include:Presence of the catheter before onset of fever.The absence of another identifiable source of infection.Presence of inflammation or purulent material at the insertion site or along the tunnel.An immunocompetent patient without any underlying disease developing bacteraemia (or fungaemia).

Aerosols are airborne particles less than 5 µm in size, containing infective organisms that usually cause infection of the upper or lower respiratory tract.Examples of organisms commonly spread by aerosol transmission are:Measles virusVaricella zoster virusMycobacterium tuberculosisThe following table summarises the various routes of transmission with example organisms:Route of transmissionExample organismsAerosol (airborne particle < 5 µm)Mycobacterium tuberculosisVaricella zoster virusMeasles virusHepatitis A and Rotavirus are spread by the faeco-oral route.Neisseria gonorrhoea is spread by sexual route.Staphylococcus aureus is spread by direct contact.

Treponema pallidum is an obligate pathogen. Obligate pathogens are almost always associated with disease and usually cannot survive outside of the body for long periods of time. Examples include and HIV.Staphylococcus aureus and Bacteroides fragilis are conditional pathogens. These are pathogens that usually cause disease only if certain conditions are met.Pneumocystis jiroveci and Pseudomonas aeruginosa, are opportunistic pathogens. These are pathogens that can only cause disease in an immunocompromised host or under unusual circumstances.

Cholera is caused by Vibrio cholerae, a motile, Gram-negative, curved bacillus. It is transmitted through water and food (especially seafood) and is primarily a disease seen in developing countries where there is poor sanitation and lack of safe water supplies.The cholera toxin leads to stimulation of adenyl cyclase, ADP-ribosylation of the G regulatory protein, inactivation of GTPase leading to active outpouring of NaCl. The cholera toxin consists of an A (the toxin) and B subunit. The B subunit attaches to the gut mucosa and presents the A subunit to the cell. The toxin stimulates adenyl cyclase by irreversible ADP-ribosylation of the GTP binding domain of adenyl cyclase leading to the opening of chloride channels resulting in an outpouring of NaCl and water into the lumen of the gut and causing secretory diarrhoea.Incubation period is between 2 and 5 days, but can be as short as just a few hours.

Patients with hypertension are only eligible for the seasonal influenza vaccination if they have co-existent cardiac complications.The UK national policy is that the seasonal influenza vaccine should be offered to the following groups:All those aged 65 years and olderChildren aged 2 to 15 yearsResidents of nursing and residential homes for the elderly (and other long-stay facilities)Carers of persons whose welfare may be at risk if the carer falls illAll those aged 6 months or older in a clinical risk groupThe following table outlines the clinical risk groups that are considered eligible for the vaccine:CategoryExamples of eligible groupsRespiratory diseaseCOPDInterstitial lung diseaseCystic fibrosisAsthma (requiring oral or inhaled steroids)Heart diseaseCongenital heart diseaseChronic heart failureCoronary heart disease (requiring medication and/or follow-up)Hypertension with cardiac complicationsKidney diseaseChronic kidney diseaseNephrotic syndromeRenal transplant patientsLiver diseaseLiver cirrhosisChronic hepatitisBiliary atresiaNeurological diseaseCerebrovascular accidentTransient ischaemic attackEndocrine diseaseType 1 and 2 diabetesImmunosuppressionPatients undergoing chemotherapyPatients taking immunosuppressive drug therapy (including systemic steroids)Asplenia or splenic dysfunctionHIV infectionPregnancyAll pregnant women

The commonest implicated organisms in hospital-acquired bacteraemia following cannulation are Staphylococcus aureus and Staphylococcus epidermidis. The risk is directly proportional to the length of time in-situ. Peripheral cannula should be replaced after 48 hours.

Staphylococcus aureus = Gram-positive coccusBacillus cereus = Gram-positive bacillusCampylobacter jejuni = Gram-negative bacillusEscherichia coli = Gram-negative bacillusIn Gram staining, crystal violet is a purple stain that is used to stain the bacteria first. The stained bacteria are decolorized and then stained with a red stain, which is safranin. Bacteria with thick cell walls keep the purple stain and are called Gram-positive. Thin-walled bacteria are easily decolorized so when safranin, the red stain, is placed on the organisms, they become red or Gram-negative. Neisseria species appear as Gram-negative diplococci because they form pairs and their adjacent ends are flattened that is why they are also described to have a coffee-bean or kidney-bean shape.

Borrelia burgdorferiis, primarily spread by ticks and lice, is a zoonotic, vector-borne organism that causes Lyme disease.Neisseria meningitidis and Bordetella pertussis are droplet borne infections (airborne particle > 5 µm)Vibrio cholerae and Ascaris lumbricoides are spread by the faeco-oral route

Plasmodium falciparum is a parasite that is vector-borne which is transmitted by the female Anopheles mosquito.Bordetella pertussis is transmitted through the respiratory tract, via respiratory droplets or direct contact with infectious secretions.Mycobacterium tuberculosis is transmitted via inhalation of infected respiratory droplets.HIV may be transmitted via sexual contact, vertical transmission from mothers to infants, and among injection drug users sharing infected needles, as well as through transfusion of infected blood products.Treponema pallidum transmission normally occurs during direct sexual contact with an individual who has an active primary or secondary syphilitic lesion.

All vaccines are contraindicated in individuals with:A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinLive attenuated vaccines are contraindicated in pregnancy except in cases where risk of infection is more than the risks of vaccination.During times of acute febrile illness, vaccination should be avoided.12 weeks should elapse after a dose of human immunoglobulin before a live vaccine is administered.The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should NOT be implemented.

Aerosols are airborne particles less than 5 µm in size containing infective organisms. They usually cause infection of both the upper and/or lower respiratory tract.The organisms can remain suspended in the air for long periods and also survive outside the body. They can be transmitted through the ventilation systems and can spread over great distances. Some examples of organisms transmitted by the aerosol route include: Varicella zoster virus, Mycobacterium tuberculosis and measles virus

Rodents and domestic animals are the primary reservoirs for the Leptospira spp, although other animals, including cows, horses, mongooses, and frogs, can also harbour the leptospires. Humans may be directly infected from animal urine or indirectly by contact with soil or water that is contaminated with urine from infected animals. Infected humans can shed leptospires in urine for up to 11 months, infected cows for 3.5 months, infected dogs for 4 years, and infected rodents possibly for their entire lifetime.The organisms enter the host through mucous membranes or abraded skin. The incubation period ranges from 5 to 14 days.

Bacillus cereus = Gram-positive bacillusNeisseria meningitidis = Gram-negative coccusSalmonella enterica & Escherichia coli = Gram-negative bacilliIn Gram staining, crystal violet is a purple stain that is used to stain the bacteria first. The stained bacteria are decolorized and then stained with a red stain, which is safranin. Bacteria with thick cell walls keep the purple stain and are called Gram-positive. Thin-walled bacteria are easily decolorized so when safranin, the red stain, is placed on the organisms, they become red or Gram-negative. The Staphylococci that are associated with infections in humans are colonizers of various skin and mucosal surfaces. Because the carrier state is common among the human population, infections are frequently acquired when the colonizing strain gains entrance to a normally sterile site as a result of trauma or abrasion to the skin or mucosal surface.

Cysts are resistant forms and are responsible for transmission of giardiasis. Both cysts and trophozoites can be found in the faeces (diagnostic stages). The cysts are hardy and can survive several months in cold water. Infection occurs by the ingestion of cysts in contaminated water, food, or by the faecal-oral route (hands or fomites). In the small intestine, excystation releases trophozoites (each cyst produces two trophozoites).Trophozoites multiply by longitudinal binary fission, remaining in the lumen of the proximal small bowel where they can be free or attached to the mucosa by a ventral sucking disk.Encystation occurs as the parasites transit toward the colon. The cyst is the stage found most commonly in non diarrheal faeces.Because the cysts are infectious when passed in the stool or shortly afterward, person-to-person transmission is possible. While animals are infected with Giardia, their importance as a reservoir is unclear.

All vaccines are contraindicated in individuals with: A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinThere is no evidence that vaccinating pregnant women with inactivated vaccine or toxoids harms the woman or foetus. The current protocol is that a child with history of egg allergy can be safely vaccinated with Fluenz tetra. However, if they had a previous severe anaphylaxis to egg requiring intensive care, then Flenz tetra is contraindicated. BCG, yellow fever or oral typhoid vaccinations are not safe in HIV positive patients.The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should not be implemented.Concurrent antibiotic therapy is not a contraindication to vaccination.