Immunocompromised Patients and Disease

Paediatric Infections (Neonatal)

• Neonatal deaths: Worldwide, more than 40% of deaths occur within the neonatal period. That is, 3.1 million newborn deaths each year. The majority of these deaths occur in low-income countries.
• Listeria monocytogenes: This bacterium is a significant cause of neonatal infections. It's a foodborne zoonosis that can pass from pregnant women to their fetuses and newborns, potentially causing septicemia, meningitis, and other severe complications. Risky foods include raw sprouts, soft cheese, smoked fish, and raw milk.
• Whooping cough (Pertussis): Caused by Bordetella pertussis, this highly contagious respiratory infection can be fatal, particularly in infants under 4 months old. It is spread through respiratory droplets and is characterized by distinctive paroxysmal coughing episodes. Vaccination is a crucial preventative measure. Pregnant women should get vaccinated. Babies, people with a weak immune system and those with waning immunity are at risk.
• Neonatal Infections: Common causes include E. coli, Staphylococcus aureus, Streptococcus agalactiae (Group B Strep), Listeria monocytogenes, and Haemophilus influenzae.
• Risk factors in the mother for early-onset infections include: invasive group B strep infection, prelabour rupture of membranes, preterm birth, intrapartum fever.
• Clinical indicators in the baby for possible early-onset infections include: altered behavior, feeding difficulties, abnormal heart rate, signs of respiratory distress, jaundice, need for mechanical ventilation, persistent fetal circulation, temperature abnormalities, signs of shock & unexplained bleeding, oliguria, altered glucose (hypo/hyperglycemia).
• Treatment of possible infections: Antibiotics such as penicillin or gentamicin should be administered rapidly - ideally within one hour of making the decision to treat.

Geriatric Infectious Diseases

 - Geriatric population demographics: The elderly population (defined in this context as individuals >65 years old) is rapidly increasing globally. This trend has significant implications for healthcare systems and infectious disease management.

• Increased risk factors: Factors like lifestyle, pre-existing health conditions (e.g., diabetes, heart disease and organ dysfunction) and diminished immunity contribute to higher susceptibility of the elderly to infections.
• Healthcare-associated infections (HCAIs): These infections are a significant public health concern particularly amongst older adults who are often in long-term care facilities (LTCFs). Relocation between nursing homes is a crucial factor in the transfer and spread of antimicrobial resistance (AMR).
• Common infections: Common infections include respiratory and gastrointestinal infections. Nosocomial infections (occur within hospital setting), UTIs, hospital acquired pneumonia and bacteremia are frequent.
• Pneumococcal diseases: This highly contagious bacterial disease is a significant risk factor for the elderly, frequently leading to hospitalization and increased morbidity and mortality, in part, due to the consequences of complications from bacteraemia and meningitis. A vaccine is available.
• Influenza: Influenza (flu), especially strains A and B, are seasonal illnesses that pose a significant health risk for the elderly, due to their increased susceptibility to complications such as pneumonia, cardiac respiratory failure, and exacerbation of pre-existing conditions.Vaccination is recommended.
• Infections relating to chronic diseases associated with compromised immunity in the elderly, such as diabetes, is an important consideration—the physiological dysfunctions can affect susceptibility to infections.
• Mucormycosis (Zygomycosis): A potentially serious fungal infection is a risk for the elderly. Infections often related to compromised immunity.

Infections in Individuals with Primary Immunodeficiencies

• Primary immunodeficiencies: Hereditary or congenital deficiencies in the immune system.
• Defects in phagocyte function: Severe infections due to common pathogens and frequent granulomas (collections of immune cells).
• Complement deficiencies: Rheumatoid disorders, lupus and scleroderma,
• B-cell immunodeficiencies: Recurrent respiratory tract infections and chronic gastrointestinal infections. 
• T-cell immunodeficiencies (Combined immunodeficiencies): T-cell immunodeficiencies (typically combined with B dysfunctions) can also cause failure to thrive and oral thrush. 
• Chronic granulomatous disease (CGD): A hereditary disease in which neutrophil granulocytes are unable to destroy certain types of ingested pathogens. Consequently it leads to potentially life-threatening infections by a wide range of microbes such as Staphylococcus aureus, Burkholderia cepacia complex, Serratia marcescens, Nocardia sp., and Aspergillus.