Study Guide for Infectious Disease

Study Guide for Infectious Disease


  • Bacteria are broadly classified into gram-positive (staphylococci, streptococci, and enterococci) and gram-negative (the rest)
  • Antibiotics can also be specific for gram-negative, gram-positive, or broad spectrum
  • The broad spectrum covers both gram-negative and gram-positive classes of bacteria (Savaris et al., 2020)

Study Guide for Infectious Disease

Antibiotic classes and their indications

Class/example Class of bacteria Common Indications
Penicillins (e.g., amoxicillin) Broad Urinary tract infections (UTIs), sexually transmitted infections (STIs), skin infections

(e.g., Gentamicin)

Gram-negative Gastroenteritis, bacterial colitis, bacteremia
Sulfonamides (e.g., sulfasalazine) Broad spectrum Inflammatory bowel disease, burns, UTIs, keratitis, endophthalmitis, and conjunctivitis
Tetracyclines (e.g., tetracycline and doxycycline)  Broad spectrum Pelvic inflammatory disease (PID), Other Sexually Transmitted Infections, and Lyme disease


Garam positive Methicillin-resistant staph aureus infections (MRSA), endocarditis, dermatitis
Clindamycin (lincosamide) Gram-positive Pneumonia, osteomyelitis, dermatitis, pelvic abscess, endometritis, PID, bacterial vaginosis (Savaris et al., 2020)


Broad spectrum UTIs, abdominal infections, acute pancreatitis, cystic fibrosis, pneumonia, bacterial meningitis
Cephalosporins Broad spectrum Pneumonia, UTI, skin infections
Macrolides (e.g., erythromycins and azithromycin) Gram-positive Sinusitis, pharyngitis, pneumonia, STIs, peptic ulcer disease (PUD), urinary tract infections
Fluoroquinolones Broad spectrum Pneumonia and UTI


  • A substance used to prove an active acquired immunity against infectious agents and diseases
  • Can be classified by method of production live attenuated, killed whole organism, recombinant, toxoid, polysaccharide, and glycoconjugate

Live attenuated

  • Also weakened vaccine
  • From an alive organism whose virulence has been reduced
  • Examples include measles, smallpox, BCG for TB, rubella, influenza, oral polio, rotavirus, rabies, typhoid, and yellow fever (Pollard & Bijker, 2021)
  • Risk of reverting to virulence
  • Sometimes, multiple doses may be given to induce a strong immune response
  • Measle, Mumps, and rubella (MMR) vaccine is commonly used type internationally
  • MMR is given to the pediatric population older than 12 months
  • Rash and fever are common adverse effects that disappear with time
  • Need to reassure the patient about these adverse events
  • Used cautiously among immunocompromised individuals

Killed Orgasm Vaccine

  • Also inactivated vaccines (Shocking Journals, 2019)
  • Inactivated by health or chemicals
  • Require an adjuvant to enhance their immunogenicity (Centers for Disease Control and Prevention (U S), 2021)
  • The main examples are inactivated polio vaccine (IPV), whole cell pertussis vaccine, hepatitis A, Rabies, cholera, influenzas, tick-borne encephalitis, and rabies (Woo, 2022).

Subunit vaccine

  • Made from an antigenic portion of a bacteria or virus
  • These units can be polysaccharides or proteins in compositions
  • Examples are conjugate vaccines such as pneumococcal conjugate vaccines, Hemophilus influenza type B, meningococcus C, and typhoid (Vi)
  • Polysaccharide subunit vaccines are not effective in children under age 2

Toxoid Vaccines

  • Made from inactivated toxins from bacteria
  • Examples include tetanus toxoid, diphtheria, acellular pertussis, anthrax, influenza subunit
  • The Novavax COVID-19 vaccine is one novel example under this class (Mayo Clinic, 2022)
  • Tetanus and diphtheria toxoid vaccines are purified from the pathogen itself

Recombinant vaccines

  • Also called genetic vaccines
  • Made through recombinant technology
  • Are produced from recombinant DNA technology
  • Examples include the hepatitis B vaccine (HBV), human papillomavirus (HPV), cholera toxin B, hepatitis E vaccine, and meningococcus B
  • Most Covid-19 vaccines are made from recombinant RNA technology (British Society for Immunology, 2021)
  • The recombinant RNA leads to translational production of antigenic SARS Cov2 to invoke an immune response, thus, immune memory

Vaccine considerations

  • All children in the US should receive MMR – at least 2 doses
  • First MMR dose after 12 months of age
  • A second MMR dose must come at least 28 days after the previous dose – recommended after 4 years of age
  • Flu vaccine can start at 6 months of age
  • Children younger than 12 months do not receive live vaccines
  • Allergies to eggs are an important consideration before vaccination
  • Injection site swelling, redness, and pain are common adverse events.
  • Severe immunosuppression is an absolute contraindication of vaccines
  • Encephalopathy within a week after pertussis vaccination warrants stoppage of subsequent doses (Centers for Disease Control and Prevention (U S), 2021)

Vaccine Precautions

  • Guillain Barre Syndrome in less than 6 weeks after the previous dose
  • Guillain Barre Syndrome in less than 6 weeks after the previous dose – of influenza vaccines
  • Thrombocytopenia or purpura – MMR
  • Chronic gastrointestinal disease – rotavirus
  • History of Arthus type reaction – tetanus toxoid, diphtheria
  • Progressive neurologic disorder – diphtheria

Vaccines in Pregnancy and Breastfeeding

  • A pregnant mother should receive inactivated influenza and Tdap vaccines
  • No live attenuated vaccines are recommended during pregnancy
  • Only if indicated, HBV vaccine, hepatitis A vaccine, and meningococcal can be given
  • Yellow fever vaccine can be given with caution to lactating mothers
  • Breastfeeding is not a contraindication to any vaccination
  • A hygienic strategus is recommended for the mother and close family members

Kawasaki disease

  • Was initially referred to as mucocutaneous lymph node syndrome
  • Vasculitis of the medium vessels
  • Rarer before 5 but common after 2 years
  • In most cases in the east, especially in Japan
  • More males were affected than females
  • Common in winter and spring

What is presentation? What do you find in physical exam?

  • Acute and self-limiting disease in most cases
  • Persistent hotness of body that can last more than 5 days
  • Rash and conjunctivitis
  • Strawberry tongue
  • The convalescent phase is marked by sole and palm desquamations
  • Arthritis can also ensue

What are the diagnostic criteria?

  • The patient must meet at least five of the following six criteria
  • Fever lasting more than 5 days
  • Nonexudative bilateral conjunctivitis
  • Oral changes – strawberry tongue, pharyngitis, fissured lips, or oral erythema
  • In the extremities – edema, desquamation, erythema, or peeling around the nails
  • Polymorphous rash
  • At least more than 1.5 cm cervical lymphadenopathy

Are any diagnostics needed?

  • Echocardiogram to rule out cardiac complications
  • Complete blood count for leukocytosis and thrombocytosis
  • Liver function tests – marked liver enzymes elevations
  • Erythrocyte sedimentation rates

How are these patients managed?

  • Acute phase – aspirin and intravenous immunoglobulin
  • In the long term – aspirin can prevent coronary artery aneurysms
  • Coronary artery bypass grafting (CABG) may be required in cases of coronary artery aneurysm

Do they need a referral? What type?

  • Cardiologist for suspected carditis
  • Cardiothoracic surgeon for suspected coronary artery aneurysms


  • Caused by influenza viruses types A and B
  • Airborne transmission

What is the presentation of the illness? What is found on physical examination

  • Fever, anorexia, fatigue, rigors, headache, nausea, vomiting,
  • Photophobia, conjunctivitis
  • Cough, coryza

Who should receive immunization?

  • Pregnant mothers (Centers for Disease Control and Prevention (U S), 2021)
  • Adults aged 65 years
  • Toddlers above 12 months of age
  • Chronic obstructive pulmonary disease and asthma
  • Chronic kidney, liver, or heart failure
  • Immunosuppressed (mild and moderate)

Who should not receive immunization?

  • Those receiving live injected vaccines
  • Those who developed GBS within 6 weeks after the previous Flu Mist dose
  • Patients allergic to egg or egg-containing products who showed symptoms other than hives

What are the complications?

  • Bacterial pneumonia
  • Viral pneumonia
  • Sepsis, sinusitis, otitis media, bronchitis
  • Severe acute respiratory syndrome (SARS) (McCance & Huether, 2018)

What diagnostic tests are used for diagnosis?

  • Compete, blood count,
  • C-reactive protein levels
  • Chest x-ray to rule out pneumonia
  • Sputum culture and examination

How is the disease managed pharmacologically?

  • Neuraminidase inhibitors such as oseltamivir and zanamivir
  • Acetaminophen for headaches and pyrexia
  • Vaccination for the population at risk
  • Antibiotics within four hours at presentation to prevent pneumonia

How is the disease managed non-pharmacologically?

  • Rest
  • Hydration
  • Oral and endotracheal tube hygiene to reduce the risk of ventilator-associated pneumonia (VAP)
  • Prevention aspiration to prevent pneumonia
  • Isolation of immunopurified individuals

Fifth Disease

  • Also called erythema infectiosum
  • What is the causative pathogen and mode of transmission?
  • Caused by parvovirus B19, also called retrovirus
  • The mode of transmission is through the air in aerosol droplets, saliva, sneezing, and nasal mucous
  • Blood and blood products can also transmit this virus from an infected person.
  • What is the NP’s role if a pregnant patient is exposed?
  • Establish contact and exposure
  • Educate patient on hygiene such as handwashing
  • Educate patient about possible outcomes through rare such as miscarriage and fetal anemia
  • Closely monitor the mother through obstetric ultrasounds
  • Referral to an obstetrician
  • Rash with a prodrome. Know the type of rash (lacelike appearance). How long does the rash last?
  • Signature rash “slapped cheek” – malar rash, laced network appearance, common in limbs and trunk, disappears within two weeks (CDC, 2022b)
  • Prodromal headache, malaise, fever, and myalgia

What typical age of patients that are infected? This can help confirm the diagnosis.

  • Common among children between 2 and 5 years (2-10%)
  • Prevalence increases in adults older than 20 years – 40-60%
  • Commoner in adults above 70 years more than 80% (Macri & Crane, 2022)

What are complications in adults and their management

  • Polyarthritis – symmetrical, small joints affected (CDC, 2022b)
  • Anemia – rare
  • Management usually symptomatic in regular patients
  • Polyarthritis among managed by NSAIDs
  • Transfusion might be required in immunocompromised patients with anemia
  • Papular Purpuric Gloves and Socks Syndrome can occur among young adults

Rocky Mountain spotted fever and lyme disease

  • Rocky Mountain spotted fever is caused by the strict intracellular parasite Rickettsia rickettsii from a tick bite (McCance & Huether, 2018)
  • Lyme disease caused by Borrelia burgdorferi from

What is presenting S&S of each? How do they differ?

  • RMSF – fever, rash (2-4 days later), headache, nausea, vomiting, myalgia, poor appetite, abdominal pain
  • Lyme disease – fever, headache, erythema migrans, and fatigue (CDC, 2022a)
  • The splotchy or spotty rash is specific to RMSF
  • Bull’s eye rash specific to Lyme disease
  • In some cases, Lyme disease can cause neck stiffness, arthralgia, dizziness, and facial palsy

What diagnostic tests are used to confirm if any?

  • ELISA test or western blot for Lyme disease
  • For RMSF, serology becomes positive after convalescence – immunofluorescent antibody, latex agglutination, and ELISA
  • Basic tests such as CBC and liver function are also important but nonspecific

What are differential diagnoses?

  • Ehrlichiosis
  • Typhus
  • Tularemia
  • Bacterial meningitis
  • Q-fever
  • Typhoid fever

What are the non-pharmacological and pharm management for adults and children?

  • Doxycycline for all ages for RMSF
  • Doxycycline is also available for Lyme disease treatment but only from 8 years of age and above
  • Patients younger than 8 years can use amoxicillin or cefuroxime
  • Avoiding tick contacts
  • Showering immediately after coming from tick-infested areas
  • Tick removal involves the use of tweezers to steadily and evenly pull out the tick and cleaning the area thoroughly using alcohol or soap and water (CDC, 2022a)

 When do you refer?

  • In cases of complications such as carditis, reactive arthritis, or Post-Treatment Lyme Disease Syndrome
  • Meningitis symptoms, fever, petechial rash
  • Recurrence of acute symptoms after treatment after 2-4 weeks
  • Know that no child under 8 should get doxycycline unless it is for RMSF.


  • Also known as the kissing disease
  • EBV is the main causative agent
  • CMV has also been implicated in some cases

What is the disease presentation? What is found in a physical exam?

  • Symptoms – Fever, Arthralgia, malaise
  • Signs – lymphadenopathy, fever, pharyngitis; sometimes splenomegaly and hepatomegaly

How do you differentiate between mono and group A strep?

  • IM has a triad of lymphadenopathy, fever, and pharyngitis
  • Streptococcal pharyngitis is caused by bacterial infection and may present with exudative tonsillitis and pharyngitis
  • Additionally, IM has fatigue and myalgia that I rare in streptococcal pharyngitis
  • Lack of response to antibiotics highly suggests IM than streptococcal pharyngitis owing to the difference in etiology

What diagnostic testing is done?

  • Monospot testing – can cause false positives due to other infections – toxoplasmosis
  • Heterophile antibody test – quantitative antibody test – the test may not yield positive results for up to 2 weeks due to a lack of antibody
  • Peripheral blood film – atypical lymphocytes + leukocytosis
  • Antistreptolysin O (ASO) titer is an antigen test that quantifies group A anti-streptococcal antibodies
  • IgG against the EBV nuclear antigen [EBNA]) used where Monospot is inappropriate or unreliable (McCance & Huether, 2018)

How is the disease managed pharmacologically?

  • Usually, self-limiting
  • Medical interventions are required in a few cases
  • Amoxicillin or erythromycin can be used empirically or in isolated streptococcal pharyngitis cases
  • Ampicillin is contraindicated due to the risk of rash in most patients with IM
  • Analgesics and antipyretics remain the mainstay of treatment
  • Aspirin is not used among children due to the risk of Reyes syndrome
  • Ibuprofen is indicated instead
  • Steroids can be used when there is a risk or impending airway occlusion due to edema from inflammation

How is the disease managed non-pharmacologically?

  • Bedrest and retreat from strenuous activities are advised due to the risk of splenic rupture
  • When does a patient need to refrain from sports? When can they resume?
  • Splenic removal in cases of high risk of splenic rupture
  • Splenectomy must be followed by vaccinations against encapsulated bacteria Streptococcus, Meningococcus, and Hemophilus influenzae

What are POTENTIALLY fatal complications

  • Carditis
  • Thrombocytopenic purpura
  • Splenic rupture and overwhelming post-splenectomy infection (OPSI)
  • Airway obstruction
  • CNS involvement

Measles (Rubeola)

  • Also called the red measles
  • Caused by the morbillivirus virus, an RNA virus that is airborne
  • Different from the German measles/rubella

How is this disease transmitted?

  • Sneezing
  • Coughing
  • Aerosol droplets
  • Highly infectious four days before and four days after the onset of the rash

What are the 3c’s?

  • Coryza
  • Conjunctivitis
  • Cough
  • Koplik spots

What is the presentation?

  • The incubation period is up to 3 weeks (McCance & Huether, 2018)
  • Start with a fever of up to 40.5°C followed by the three C’s above
  • The cough is a barking type
  • Marked by a maculopapular rash that starts from behind the ears and spreads to the whole body
  • The rash extends to palms and soles
  • Additionally, there is malaise, runny nose, and lymphadenopathy

What are Koplik’s spots?

  • White spots on the buccal mucosa
  • Are pinpointed and surrounded by an erythematous ring
  • Appear one to two days before the rash

What diagnostic tests are needed?

  • A throat swab for polymerase chain reaction (PCR)
  • Serum IgM against rubeola virus

What are differential diagnoses?

  • Kawasaki disease
  • Systemic lupus erythematosus
  • Rubella
  • Serum sickness
  • Infectious mononucleosis
  • Roseola

What is the best prevention?

  • Vaccination is the best prevention (McCance & Huether, 2018)
  • What is given to susceptible contacts?
  • Postexposure prophylaxis with antivirals is given to susceptible individuals

Other treatments

  • Antibiotic therapy is in cases of secondary bacterial infection
  • Rest
  • Hydration
  • Vaporization of the airway


  • Also called the Exanthema Subitum or 6th Disease

What is a causative agent?

  • The causative agent is human herpesviruses 6 (HHV6) or human herpesviruses 7 (HHV7)

What is the mode of transmission?

  • Airborne transmission through droplets in the air

What age group does this typically occur in?

  • Usually between 6 and 24 months
  • Can be seen in children of up to 4 years (McCance & Huether, 2018)

How does the disease present?

  • Symptoms follow a 5-15 day incubation period
  • Fever followed by a maculopapular rash
  • The rash is seen in the trunk, arms, and neck and lasts up to 48 hours

What are differentials?

  • Rubella
  • Rubeola
  • Infectious mononucleosis
  • Lyme disease
  • Rocky Mountain spotted fever
  • Varicella zoster
  • Chickenpox

How is this disease managed?

  • Self-limiting and no treatments are usually indicated
  • Supportive care through adequate water intake

Can they return to daycare or school?

  • No time of school is required

German Measles (Rubella)

  • Also called 3-Day Measles
  • Caused by the rubella virus, an RNA virus

What is disease presentation?

  • Starts with fever, malaise, runny nose, headache, cough, lymphadenopathy
  • Followed by a pink-reddish maculopapular rash on the face, trunk, and extremities
  • What are the complications that can occur with this disease?
  • The rash can resolve spontaneously within three days

What are the differential diagnoses?

  • Rubeola
  • Roseola
  • Infectious mononucleosis
  • Lyme disease
  • Rocky Mountain spotted fever
  • Varicella zoster
  • Chickenpox
  • Hand, foot, and mouth disease

What diagnostic tests need to be done?

  • CBC to rule out thrombocytopenia
  • Rubella IgM test
  • Viral culture

Common complications

  • Encephalitis
  • Thrombocytopenia
  • Severe arthritis
  • Congenital rubella syndrome (CRS)

 How is this disease managed?

  • Mainly supportive and no definitive treatment
  • Starch baths (McCance & Huether, 2018)
  • Antihistamines
  • NSAIDs for joint involvement and pain
  • Adequate fluid intake in those at risk of encephalitis
  • Ophthalmology for CRS


  • Caused by human herpes 3/ varicella-zoster virus
  • How is this spread?
  • Spread by contact

What is the incubation period?

  • The average incubation period is two weeks but can go up to a month

What is the presentation?

  • Skin rash that starts as papules and evolves into vesicles, pustules, and crusts
  • Rah appears on the trunk, face, head, and back
  • Vesicles are sometimes itching
  • Short-course fever, usually 2 – 3 days

Management: both pharmacologic and nonpharmacologic

  • Usually, conservative
  • Analgesia – NSAIDs are discouraged due to the risk of skin and soft tissue reactions
  • Acetaminophen thus recommended
  • Neonates/immunosuppressed/cardiovascular disease risk patients – anti-varicella zoster immunoglobulin + acyclovir (McCance & Huether, 2018)
  • Antihistamines to help with itching
  • Antibiotics if the secondary bacterial infection
  • Supportive – Patient to avoid school for about 5 days from the rash onset day, bath, wet dressing

Potential complications

  • Encephalitis
  • Varicella pneumonia and laryngeal edema
  • Epistaxis
  • Congenital varicella syndrome
  • Transecting hematuria
  • Can breakthrough chickenpox occur with a vaccine?

Cellulitis and erysipelas

  • Both dermal infections

How do you differentiate the two?

  • Cellulitis involves the lower dermis
  • Erysipelas involves the upper dermis; Therefore, erysipelas is superficial cellulitis
  • Erysipelas is well-defined, but cellulitis has poorly defined margins

What are the primary causative agents of each?

  • Cellulitis – group B streptococci, MRSA, staph aureus
  • Erysipelas – group A streptococci

What is the pharmacologic treatment of each?

  • Cellulitis – antibiotics flucloxacillin; in cases of MRSA use vancomycin; per oral analgesia (McCance & Huether, 2018)
  • Erysipelas – Systematic antibiotics, analgesia

When do these need to be referred?

  • Signs of necrotizing fasciitis – rapidly spreading infection
  • Suspected DVT, lymphangitis,
  • Suspected osteomyelitis
  • Poor response to treatment
  • Cellulitis of the face


  • Know that petechiae and fever are always emergent.

What are the primary causative agents for bacterial, viral, and fungal?

  • Bacterial – strep pneumoniae, Neisseria meningitidis, Hemophilus influenza type b, Group B Streptococcus
  • Viral – Human immunodeficiency virus, mumps virus, herpes simplex
  • Fungal – cryptococcal neoformans, Histoplasma

What are Kernig and Brudzinski signs?

  • Kernig sign – positive when the patient lies in a supine position and hip is flexed, and extension at the knee causes pain (McCance & Huether, 2018)
  • Brudzinski sign – is positive when the patient flexes both knees and hip when the neck is flexed

What are the assessment findings?

  • Bulging fontanels in children
  • Opisthotonos position in children
  • Purpuric in septic meningococcal etiologies

What diagnostic testing is done?

  • CSF analysis to suggest the etiology
  • CSF culture to identify the etiological agent
  • Blood culture to rule out the septic cause
  • Complete blood count

What are the best prevention strategies?

  • Isolation in highly contagious causes
  • Public awareness
  • Early case detection
  • Vaccination
  • Prophylactic antibiotics

How is this managed?

  • Fluid therapy
  • Oxygen administration in acute settings
  • Broad-spectrum antibiotics while awaiting culture results
  • Dexamethasone if older than 3 months (McCance & Huether, 2018)


  • Caused by Bordetella pertussis (gram-negative)

What are the stages?

  • Catarrhal – fever, coryza, mod cough  – up to 10 days
  • Paroxysmal – prolonged hacking cough, whoop, more at night – can last up to 6 weeks (weeks #2 – 8)
  • Convalescent – gradual discovery, fewer coughs, – lasts up to 3 weeks  (week 8 – week 12) (CDC, 2022c)

What is the presentation?

  • Cough, vomiting, inspiratory whoop, fever, and coryza.


  • Mainly through vaccination
  • Tdap is recommended for pregnant women with every pregnancy in the third trimester.
  • Confers protection on the unborn infant as well


British Society for Immunology. (2021, April). Types of vaccines for COVID-19.

CDC. (2021, May 27). Prevention. Centers for Disease Control and Prevention.

CDC. (2022a, January 19). Lyme Disease. Centers for Disease Control and Prevention.

CDC. (2022b, February 16). Fifth Disease.

CDC. (2022c, February 23). Clinical Features.

Centers for Disease Control and Prevention (US). (2021). Epidemiology and prevention of vaccine-preventable diseases: The pink book (14th ed.). Rittenhouse Book Distributors.

Macri, A., & Crane, J. S. (2022). Parvoviruses. In Parvoviruses. [Updated ]. In: StatPearls [Internet]. Treasure Island (FL). StatPearls Publishing.

Mayo Clinic. (2022, August 25). Different types of COVID-19 vaccines: How they work. Mayo Clinic.

McCance, K. L., & Huether, S. E. (2018). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Mosby.

Pollard, A. J., & Bijker, E. M. (2021). A guide to vaccinology: from basic principles to new developments. Nature Reviews. Immunology21(2), 83–100.

Savaris, R. F., Fuhrich, D. G., Maissiat, J., Duarte, R. V., & Ross, J. (2020). Antibiotic therapy for pelvic inflammatory disease. Cochrane Database of Systematic Reviews8(8), CD010285.

Shocking Journals. (2019). Vaccine queen: Nurse notebook medical nursing school journal (6×9). Independently Published.

Woo, J. (2022). Vaccination. The American Journal of Nursing122(2), 10.