Cause 

 Septicemia refers to a serious bloodstream infection, bacteria in the blood causing a body-wide inflammatory response (sepsis). In advanced HIV, almost any severe infection can progress to sepsis. Common sources include pneumonia, abdominal infections, urinary tract infections, or central line infections. Certain bacteria are particularly noted in AIDS sepsis: for example, Salmonella species can cause recurrent sepsis (see NTS below), and Staphylococcus aureus from skin infections can invade the blood. Essentially, septicemia occurs when bacteria from a local infection enter the bloodstream and spread throughout the body. The immune system in AHD may not contain infections well, making sepsis more likely. 

Symptoms 

Sepsis symptoms can escalate quickly and are life-threatening. Hallmark signs include high fever, often with chills and shaking (rigors), low blood pressure (which can cause dizziness or fainting), rapid heartbeat, and rapid breathing. The person may become confused, disoriented, or very lethargic as sepsis worsens. In septic shock, organs start to malfunction due to poor blood flow – urine output drops, the skin may become cool and clammy, and the patient can lose consciousness. Sometimes there is an obvious focus (e.g., coughing and lung findings if from pneumonia, or abdominal pain if from an abdominal infection), but in other cases the source isn’t immediately clear. 

Diagnosis  

Diagnosis of septicemia is based on clinical signs of sepsis plus evidence of infection. Blood cultures are critical – samples of blood are taken and incubated to see if bacteria grow, which confirms bacteria in the bloodstream and identifies the type. Multiple cultures are drawn (from different sites) before starting antibiotics. Other lab findings in sepsis include very high or very low white blood cell count, elevated lactate, and organ function tests showing abnormalities (like kidney or liver tests if those organs are affected). Doctors will also search for the infection source (chest X-ray, urine test, CT scans, etc., depending on symptoms). In HIV patients, Salmonella septicemia is an AIDS-defining illness if recurrent, so stool cultures might be done too to check for Salmonella in the gut. 

Treatment 

Septicemia is a medical emergency. Treatment involves prompt IV broad-spectrum antibiotics (covering likely bacteria until specific cultures guide therapy) and supportive care in a hospital (often ICU). For example, if no source is known, doctors might give a combination like a broad-spectrum beta-lactam with coverage for Gram-negatives and staph. Once blood culture results identify the organism, antibiotics can be tailored to that bug. IV fluids are given in large amounts to raise blood pressure and improve circulation. If fluids aren’t enough, medications called vasopressors (to constrict blood vessels) are used. Supportive care may include oxygen or mechanical ventilation if breathing is failing, dialysis if kidneys fail, etc. Treating the source is equally important – e.g., draining an abscess or removing an infected catheter. With aggressive treatment, sepsis can be reversible, but it is often fatal if not rapidly controlled. 

Prevention

Preventing sepsis means preventing and promptly treating the infections that lead to it. For people with AHD, this includes prophylactic antibiotics as indicated (for example, cotrimoxazole prophylaxis reduces incidence of certain bacterial infections that could lead to sepsis). Safe food and water practices help prevent Salmonella and other gut infections that can cause sepsis. Vaccinations (pneumococcal, etc.) prevent severe infections at the source. Good hygiene and wound care prevent skin infections from becoming bloodstream infections. In healthcare settings, meticulous care of IV lines and catheters lowers risk of bloodstream infection. Most importantly, ART and improved nutrition strengthen the immune system so that infections are less frequent and less likely to become disseminated. Recognising early infection signs and seeking prompt medical care can stop a serious infection before it progresses to full septicemia. 

Cause 

 Non-typhoidal Salmonella are bacteria that typically cause food poisoning. Common species are Salmonella enteritidis and S. typhimurium. Infection is usually acquired by eating contaminated food or water, especially undercooked poultry, eggs, or produce contaminated with animal faeces. In healthy people, NTS usually causes a self-limited diarrheal illness. In people with advanced HIV, Salmonella can invade beyond the gut, entering the bloodstream. In fact, recurrent Salmonella septicemia is an AIDS-defining condition. People with HIV have at least a 20-times greater risk of invasive salmonellosis than HIV-negative individuals.

Symptoms  

Intestinal salmonellosis starts with sudden fever, diarrhoea, abdominal cramps, nausea, and sometimes vomiting. The diarrhoea can be watery or even bloody in some cases. In advanced HIV, the infection often becomes salmonella septicemia: symptoms then include high fever, chills, and signs of sepsis (as described above). The patient may or may not have ongoing diarrhea by that point – the infection can spread to the blood, joints (causing septic arthritis), or other organs (like causing liver or spleen abscesses). Recurrent episodes of fever and bacteremia are common if proper treatment and secondary prophylaxis are not given. 

Diagnosis  

A stool culture will confirm Salmonella in cases of diarrhea. In disseminated cases, blood cultures will grow the Salmonella (and this is diagnostic of Salmonella septicemia). Cultures from other sterile sites (bone marrow, joint fluid, etc., if involved) can also yield the organism. Once identified, the lab will perform sensitivity testing to guide antibiotic choice. Clinicians should test for NTS in any HIV patient with unexplained fever and GI symptoms. It’s also important to test for co-infections like other intestinal pathogens, since multiple infections can coexist in AHD. 

Treatment  

Salmonella infections in HIV require antibiotic treatment (unlike mild cases in healthy people that might recover without it). First-line treatment often includes a fluoroquinolone (like ciprofloxacin) or a third-generation cephalosporin (like ceftriaxone) for bloodstream infection, given for 10-14 days or longer depending on response. In severe cases, IV therapy is used until improvement, then one may switch to oral antibiotics. After an initial invasive Salmonella infection, patients with AHD may be kept on secondary prophylaxis with a low-dose antibiotic (such as TMP-SMX or ciprofloxacin) to prevent recurrence, until their CD4 count improves. Rehydration and electrolyte replacement are important if diarrhoea is significant. With treatment, fever usually resolves in 4-7 days and diarrhea in a few days. Without treatment, salmonellosis in HIV can be fatal. 

Prevention  

Preventing Salmonella involves food and water safety. This means avoid eating raw or undercooked eggs, poultry, or meat; wash fruits and vegetables thoroughly; drink boiled or treated water in regions where water may be contaminated. Handwashing after handling raw foods or using the bathroom is critical to stop the spread. People with HIV should be extra cautious with food hygiene and may even avoid high-risk foods like raw eggs or unpasteurized dairy. There is no vaccine for NTS (unlike typhoid fever which has a vaccine for Salmonella typhi). However, cotrimoxazole prophylaxis given to many AHD patients for PCP also offers protection against Salmonella infections. Maintaining ART and a better immune status reduces the risk of severe salmonellosis. If someone with HIV does get a Salmonella GI infection, treating it early may prevent it from spreading to the bloodstream. 

Cause  

MAC refers to infections caused by Mycobacterium avium and Mycobacterium intracellulare, environmental bacteria found in water, soil, and dust. These are atypical mycobacteria (different from TB) that rarely cause disease in people with normal immunity. In advanced HIV (especially CD4 counts <50), MAC can spread throughout the body, causing disseminated MAC disease. People can ingest or inhale these bacteria from the environment; person-to-person transmission is not a concern. 

Symptoms  

MAC in AIDS usually causes a disseminated infection (bacteria multiplying in many organs). Key symptoms are persistent fever, night sweats, weight loss, and often digestive issues like chronic diarrhoea or abdominal pain (Opportunistic Infections in HIV). Many patients have anaemia and feel extremely fatigued (because MAC often invades the bone marrow). There can be enlargement of the liver, spleen, and lymph nodes. Sometimes, MAC can also cause localised infections like lymph node infections or lung infections, but in AHD disseminated disease is more common. The symptoms develop gradually and can be mistaken for TB or other infections. 

Diagnosis  

Diagnosis is made by isolating the organism. A blood culture for mycobacteria (using special techniques) is often positive in disseminated MAC. Cultures from bone marrow or lymph nodes can also identify MAC. It takes 1-2 weeks (sometimes more) to grow in the lab. There is also an acid-fast bacilli (AFB) stain that can sometimes show the organisms in samples (like a bone marrow biopsy or lymph node biopsy). High clinical suspicion in a patient with CD4 <50 and typical symptoms often prompts empiric therapy while awaiting confirmation. 

Treatment  

Treating MAC requires a combination of antibiotics for a long duration. The standard regimen is at least two or more drugs to prevent resistance. Typically this includes a macrolide antibiotic (either azithromycin or clarithromycin) plus ethambutol. A third agent is often added; rifabutin is commonly used, or sometimes a fluoroquinolone or injectable agent in severe cases. Therapy is given for at least 12 months and until the patient’s CD4 count is above 100 on ART. Symptoms improve slowly over weeks as the bacterial load reduces. If anemia or other organ issues were present, those also recover with treatment. It’s crucial for patients to also start ART; immune recovery helps clear MAC. However, ART is usually started after a couple weeks of MAC therapy to reduce the risk of immune reconstitution inflammatory syndrome (IRIS). 

Prevention 

For patients with CD4 <50, primary prophylaxis for MAC is recommended in many guidelines. This usually involves taking azithromycin (1200 mg once weekly) or clarithromycin (500 mg twice daily) as a preventive antibiotic. Studies showed this significantly lowers the risk of MAC disease. If a patient initiates effective ART and maintains an undetectable viral load, some clinicians may defer MAC prophylaxis, but in resource-limited settings prophylaxis is often used routinely until immune recovery. Besides medication, general avoidance of potential sources like untreated water or soil dust might be advised, though MAC is ubiquitous so it’s hard to avoid completely. Staying on ART and keeping the CD4 count up is the best long-term prevention. There is no vaccine for MAC. Note that treating other opportunistic infections and maintaining nutrition also indirectly help by improving overall immunity. 

Cause 

Skin and soft tissue infections (SSTIs) in AHD are often caused by common bacteria entering through breaks in the skin. Staphylococcus aureus (including MRSA, the methicillin-resistant strain) is a frequent culprit, causing boils, abscesses, and cellulitis. Streptococcus pyogenes (Group A strep) can cause cellulitis and rarely necrotizing fasciitis (flesh-eating infection). People with HIV, especially with low CD4 counts, have a higher risk of MRSA skin infections and often get more severe or recurrent SSTIs. Other bacteria (like Pseudomonas or atypical mycobacteria) can cause skin ulcers in immunocompromised hosts, but staph and strep are most common. 

Symptoms  

SSTIs can range from localized to systemic. Cellulitis presents as a red, warm, tender area of skin that spreads – often on the legs. The skin may be swollen and the person can have fever and chills if it’s severe. Abscesses (boils) are painful, pus-filled lumps under the skin; the skin is red and the center may be soft or draining pus. Folliculitis (infection of hair follicles) causes small pus bumps. In MRSA infections, abscesses are especially common. If an infection becomes deep or spreads, one might see necrosis (dead tissue) or blisters. Advanced HIV patients can get unusually extensive lesions or multiple sites at once. If bacteria enter the bloodstream from a skin infection, symptoms of sepsis (see above) can occur. 

Diagnosis 

Diagnosis is usually clinical by examining the skin. The doctor may mark the edges of redness to track if cellulitis is spreading. Pus culture: If there is an abscess, incision and drainage is done and the pus is cultured to identify the bacteria and check antibiotic sensitivity (especially to detect MRSA). Blood cultures are taken if there is fever or concern the infection has spread. In chronic or non-healing ulcers, a biopsy might be done to rule out other organisms (e.g., fungi or mycobacteria). 

Treatment 

The first step for any abscess is drainage – releasing the pus. Small abscesses may drain with a warm compress, larger ones need incision by a healthcare provider. Antibiotic choice depends on the organism; often treatment is started empirically for staph and strep. For community MRSA, antibiotics like trimethoprim-sulfamethoxazole, doxycycline, or clindamycin are often used. For non-resistant staph or strep, dicloxacillin or cephalexin (oral) might be sufficient. Severe cellulitis may require IV antibiotics (like vancomycin for MRSA or cefazolin for MSSA). Duration is typically 7-14 days, depending on response. Wound care is important: keeping the area clean, possibly using antiseptic dressings. Patients with very low CD4 who get recurrent SSTIs might be given suppressive antibiotics, but this is not routine due to resistance risk. With proper treatment, most skin infections improve within a week (redness and pain subside). Extensive necrotic or gangrenous infections may require surgical removal of dead tissue. 

Prevention  

Good hygiene is the cornerstone. Regular bathing and handwashing, especially if one has cuts or scrapes. Any small cut or wound should be cleaned promptly and kept clean; using an antiseptic and a clean bandage can prevent infection. People with HIV should avoid sharing personal items like razors or towels that can carry staph. Because HIV increases MRSA risk, some clinics promote nasal mupirocin or antibacterial washes for those with recurrent MRSA. Avoiding injection drug use (or using sterile needles) prevents deep skin infections and abscesses from injections. Proper management of athlete’s foot or other skin conditions is important, as these can provide entry points for bacteria. Nutrition and ART also play a role – a healthier immune system means the skin can fend off minor invaders better. Finally, in healthcare settings, standard precautions (gloves, disinfecting skin before IVs or injections) reduce risk of introducing bacteria into the skin. By staying generally healthy and addressing skin issues early, many SSTIs can be prevented or caught before they become severe.