Immunocompromised persons Infections

Listeriosis can cause sepsis and meningitis, particularly in elderly and immunocompromised persons. Infection during pregnancy produces a mild, flu-like illness in the mother but serious intrauterine infection resulting in fetal death, neonatal sepsis, or meningitis. 

The number of immunocompromised persons is continually increasing as advances are made in medicine. The life expectancy for persons with cancer, HIV infection, and solid organ or bone marrow transplantation is increasing. Vaccination provides one tool to prevent infection in the immunocompromised host however, the individual s immuno-suppressed state will alter the response to vaccine. In general all vaccinations should be updated prior to the person becoming immunosuppressed, if possible. Once a person becomes significantly immunosuppressed, live virus vaccines should be avoided. 

Kohl KS, Marcy SM, Blum M, et al. Fever after immunization current concepts and improved future scientific understanding. Clin Infect Dis 2004 39 389-394. MacKay IR, Rosen FS. Vaccines and vaccination. N Engl J Med 2001 345 1042-1053. Moylett EH, Hanson IC. Mechanistic actions of the risks and adverse events associated with vaccine administration. J Allergy Clin Immunol 2004 114 1010-1020. Rhee P, Nunley MK, Demetriades D, et al. Tetanus and trauma a review and recommendations. J Trauma 2005 58 1082-1088. Weber DJ, Rutala WA. Immunization of immunocompromised persons. Immunol Allergy Clin North Am 2003 23 605-634. 

Immunocompromised A condition in which the immune system is not functioning normally. This condition is seen in the very young, the very old, human immunodeficiency virus-infected individuals, and in transplant patients. An immunocompromised person is susceptible to opportunistic infections. 

Progressive multifocal leukoencephalopathy (PML) is historically a rare demyelinating disease that is usually associated with disorders of the reticuloendothelial system, neoplasias and immunosuppressive therapy [1, 2]. However, it has become more important in clinical medicine because it is frequently seen as an opportunistic secondary infection in immunocompromised persons with AIDS. PML is characterized by focal lesions that are noninflammatory and caused by infection of oligodendrocytes with the JC papovavirus. 

B. cants is the species of Brucella species that can infect dogs, This species has occasionally been transmitted to humans, but the vast majority of dog infections do not result in human illness. Although veterinarians exposed to blood of infected animals are at risk, pet owners are not considered to be at risk for infection. This is partly because it is uniikely that they will come in contact with blood, semen, or placenta of the dog. The bacteria may be cleared from the animal within a few days of treatment however re infection is common and some animal body fluids may be infectious for weeks. Immunocompromised persons (cancer patients, HIV-infected individuals, or transplantation patients) should not handle dogs known to be infected with B. cams. 

The list of opportunistic infections and cancers mentioned before only covers the most commonly encountered diseases. Numerous other infections are also seen at lower frequency. These diseases are only a fraction of potential diseases that could affect immunocompromised persons, as HIV destroys only certain parts of the immune system. 

The esters also react readily with aryl hydrazines to give aryl hydrazone derivatives. Examples of the latter were first synthesized (prior to the availability of tetraalkyl carbonylphosphonates) from tetraalkyl methylenebisphosphonates and aryl diazonium salts, analogously to the phosphonoglyoxylate hydrazone synthesis described in a previous section. First made as possible precursors in a ketone synthesis, several of these compounds, converted to free acid salts by treatment with BTMS followed by dicyclohexylamine in methanol, proved to have unexpected inhibitory activity vs the pyrophosphate-dependent phospho-fructokinase of the parasite T. gondii, which causes a potentially lethal opportunistic infection in immunocompromised persons such as AIDS patients [94]. In fact, the 2,4-dinitrophenylhydrazone of carbonylbisphosphonic acid (as the tetrasodium salt) dramatically abated toxoplasmosis lesions in infected human foreskin fibroblasts [94]. Animal toxicity in this compound, probably arising from in vivo hydrolysis to the highly toxic hydrazine, precluded its future development, but the result remains an interesting lead. 

Patients with inactive tuberculosis who have not received adequate therapy should be considered for 1 year of isoniazid treatment. HIV-infected intravenous drug abusers with a positive PPD test have 8% chance per year of developing active tuberculosis. Isoniazid prophylaxis in HIV-infected persons appears to be as effective as in non-immunocompromised persons. The CDC recommends that isoniazid prophylaxis be continued for 12 months. Persons infected with HIV who are exposed to multidrug-resistant tuberculosis should receive prophylaxis with rifampin and pyrazinamide (with close monitoring for hepatic toxicity) or high-dose ethambutol and pyrazinamide, with or without a fluoroquinolone. 

Cytomegalovirus (CMV) is a herpesvirus, which causes an inapparent infection in immunocompetent persons. Worldwide, approximately 40% of people are infected with CMV. In immunocompromised patients, transplant recipients and neonates, CMV can cause serious and potentially lethal disease manifestations like pneumonia, retinitis and blindness, hepatitis, infections of the digestive tract, deafness or mental retardation. 

Antibodies against HCV (anti-HCV) in the blood indicate infection with the HCV. If the infection persists for more than 6 months and viral replication is confirmed by HCV RNA levels, then the person has chronic hepatitis C. Chronic disease may be due to an ineffective host immune system against the HCV. Cytotoxic T lymphocytes are ineffective in eradicating the HCV, thus allowing persistent damage to hepatic cells. Therefore, immunocompromised individuals are less likely to eliminate HCV.12... 

Cellulitis is a bacterial infection of the dermis and subcutaneous tissue. S. aureus and P-hemolytic streptococci are the most common causes of acute cellulitis in otherwise healthy hosts. Persons who are immunocompromised, have vascular insufficiency, or use injection drugs are at risk for polymicrobial cellulitis. 

Once infected with M. tuberculosis, a person s lifetime risk of active TB is about 10%, with about half this risk evident during the first 2 years after infection.2,3,6 Young children, the elderly, and immunocompromised patients have greater risks. HIV-infected patients with M. tuberculosis infection are roughly 100 times more likely to develop active TB than normal hosts owing to the lack of normal cellular immunity.3,9... 

Caseating granulomas, regardless of location, can undergo liquefaction, spread tubercle bacilli and cause symptoms.2,6 Because of muted or altered symptoms, the diagnosis of TB is difficult and often delayed in immunocompromised hosts.2,3,6 HIV-infected patients may present with only extrapulmonary TB, which is very uncommon in HIV-negative persons. A widely disseminated form of the disease called miliary TB can occur, particularly in children and immunocompromised hosts, and it can be rapidly fatal.17 Immediate treatment is required. 

The route of influenza transmission is person-to-person via inhalation of respiratory droplets, which can occur when an infected person coughs or sneezes. The incubation period for influenza ranges between 1 and 4 days, with an average incubation of 2 days. Adults are considered infectious from the day before their symptoms begin through the fifth day after the onset of illness, while children can be infectious for longer than 10 days after the onset of illness. Viral shedding can persist for weeks to months in severely immunocompromised people. 

Immunocompromise is a contraindication to the use of live virus vaccines, such as measles, mumps, rubella, and oral poliomyelitis vaccine. It is recommended that rubella or MMR vaccine should not be given to persons who are immunosuppressed because of AIDS or other clinical manifestations of HIV infection. The vaccine can be given to asymptomatic infected people (139). 

The Immunization Advisory Committees of many developed countries recommend that OPV should not be given to children and young adults who are immunocompromised due to AIDS or other clinical manifestations of HIV infection. OPV can be given to asymptomatic infected persons. However, because family members may be immunocompromised due to AIDS or HIV infection, it seems prudent to use IPV (48). 

The most severe CMV infections are seen in those individuals who acquire their primary infection while immunocompromised. In persons with AIDS, CMV disease rarely occurs when the CD4+ cell count is above 100 cells/mm the most common clinical presentations are retinitis, esophagitis, and colitis. In transplant recipients, the occurrence and severity of CMV disease are related to the CMV serostatus of the organ donor and recipient, the type of organ transplanted, and the overall degree of immunosuppression. For example, CMV disease tends to be more severe in lung transplant recipients than in renal transplant recipients. For aU types of organ recipients, the most severe disease occurs... 

The standard methods for detection of MTb include acid-fast bacilli (AFB) smear and conventional and liquid culture methods. The AFB smear is rapid, but has a poor sensitivity of 20% to 80%. Another challenge with the AFB smear is that it cannot distinguish MTb from nontuberculous mycobacteria (NTM), such as M. avium-complex (MAC). This distinction is important because disseminated MAC and MTb are both common infections in persons with AIDS. Culture methods for the detection of MTb are sensitive, but growth detectable by standard methods may require 6 to 8 weeks in a culture. Growth often occurs more quickly in liquid culture than with conventional methods, but can still require weeks. With these limitations of culture methods, there was great enthusiasm for nucleic acid testing as a rapid, sensitive method for detection of MTb, especially given the needs to rapidly isolate patients with active, untreated disease and to initiate prompt therapy, particularly in immunocompromised hosts. 

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