Gram-negative bacillary bacteremia in human immunodeficiency virus type 1-infected children

Chronic lung disease in human immunodeficiency virus (HIV) infected children

The development of chronic lung disease is common in HIV-infected children. The spectrum of chronic HIV-associated lung disease includes lymphocytic interstitial pneumonia (LIP), chronic infections, immune reconstitution inflammatory syndrome (IRIS), bronchiectasis, malignancies, and interstitial pneumonitis. Chronic lung disease may result from recurrent or persistent pneumonia due to bacterial, mycobacterial, viral, fungal or mixed infections. In high tuberculosis (TB) prevalence areas, M. tuberculosis is an important cause of chronic respiratory illness. With increasing availability of highly active antiretroviral therapy (HAART) for children in developing countries, a rise in the incidence of IRIS due to mycobacterial or other infections is being reported. Diagnosis of chronic lung disease is based on chronic symptoms and persistent chest X-ray changes but definitive diagnosis can be difficult as clinical and radiological findings may be non-specific. Distinguishing LIP from miliary TB remains a difficult challenge in HIV-infected children living in high TB prevalence areas. Treatment includes therapy for specific infections, pulmonary clearance techniques, corticosteroids for children with LIP who are hypoxic or who have airway compression from tuberculous nodes and HAART. Children who are taking TB therapy and HAART need adjustments in their drug regimes to minimize drug interactions and ensure efficacy. Preventative strategies include immunization, chemoprophylaxis, and micronutrient supplementation. Early use of HAART may prevent the development of chronic lung disease.

Molecular epidemiology of community-acquired invasive non-typhoidal Salmonella among children aged 2–29 months in rural Gambia and discovery of a new serovar, Salmonella enterica Dingiri

Sixty-two invasive non-typhoidal Salmonella (NTS) isolates from children aged 2–29 months in rural Gambia were examined for serovar prevalence and antimicrobial susceptibility, and characterized using multilocus sequence typing (MLST) of seven genes, aroC, dnaN, hemD, hisD, purE, sucA and thrA. Salmonella enterica serovar Enteritidis was the most common serovar (80.6  %), followed by S. enterica serovar Typhimurium (8.0  %). Thirty-three per cent of the isolates were resistant to all eight antimicrobials tested, including ampicillin (74.2  %), cotrimoxazole (64.5  %) and tetracycline (63  %). A total of 40.3  % of the NTS cases had an initial clinical diagnosis of malaria, whilst 27.3  % had a diagnosis of clinical pneumonia and 18  % had a diagnosis of septicaemia. MLST of NTS resulted in ten different sequence types (STs), of which five were novel, representing five different NTS serovars. In general, STs were restricted to the same serovar. One type (ST11) encompassed 80.6  % of the NTSs. A new NTS serovar named S. enterica serovar Dingiri was discovered. S. Dingiri was isolated from a 6-month-old male with an initial clinical diagnosis of malaria but a final clinical diagnosis of anaemia and septicaemia. S. Dingiri, which possesses an antigenic formula of 17:z:1,6, was sensitive to ampicillin, cefotaxime, chloramphenicol, ciprofloxacin, cotrimoxazole and tetracycline but resistant to gentamicin, and was ST338.

Comorbidities and mortality among children hospitalized with diarrheal disease in an area of high prevalence of human immunodeficiency virus infection

PURPOSE

To describe the profile of comorbidities in children admitted with diarrhea to an urban hospital with high human immunodeficiency virus (HIV) prevalence in South Africa and to examine the contribution of comorbidities to inpatient mortality.

METHODS

Data from a retrospective random sample of 319 children were extracted and analyzed from a total of 1145 children hospitalized for diarrhea in 2001. We used multiple logistic regression models to determine the independent effects of HIV infection, malnutrition, pneumonia and bacteremia on inpatient mortality.

RESULTS

Overall 68% of the diarrheal admissions were classified as HIV-infected and 61% were classified as malnourished, with 53% having evidence of both. HIV infection was strongly associated with malnutrition, pneumonia and bacteremia. Inpatient mortality was 14% [95% confidence interval (CI), 11-19%]. Mortality was higher among HIV-infected than among uninfected children [crude odds ratio (OR), 6.0; 95% CI 2.1-17.0]. History of low birth weight, previous admission, malnutrition, HIV infection, pneumonia, bacteremia, low hemoglobin, total white blood cell count and serum albumin were significant predictors of mortality in univariate analyses. After adjustment, severe malnutrition (OR 2.1; 95% CI 1.0-4.9), bacteremia (OR 2.9; 95% CI 1.2-7.2) and pneumonia (OR 3.9; 95% CI 1.3-12.0) remained independent predictors of mortality, whereas the association between HIV infection and mortality was significantly diminished (OR 4.0; 95% CI 0.8-18.1).

CONCLUSION

In a setting of high HIV prevalence, malnutrition, bacteremia and pneumonia contribute independently to death in children hospitalized with diarrheal disease.

Sepsis predisposition in children with human immunodeficiency virus

OBJECTIVE

To review predisposition to sepsis in children infected with human immunodeficiency virus (HIV) in the era of highly active antiretroviral therapy (HAART).

DESIGN

Summary of the literature with review by experts in the field.

RESULTS

In industrialized regions, new diagnoses of vertically acquired HIV infection are falling due to perinatal interventions. Provision of HAART has resulted in an enlarging cohort of clinically stable HIV-infected children, with low viral loads and normal CD4 T-lymphocyte counts. Access to HAART in "developed" countries has markedly decreased the rate of progression to acquired immunodeficiency syndrome, the prevalence of organ-specific complications of HIV, the risk of recurrent sepsis, and the high early childhood mortality from HIV infection. There are currently no data on whether initiation of HAART during acute sepsis reduces short-term morbidity or mortality. Undiagnosed, antiretroviral-naive, HIV-infected infants still present sporadically with opportunistic infections such as Pneumocystis jiroveci and cytomegalovirus pneumonia. HIV-infected children have a greater burden of disease due to viral, bacterial, and fungal sepsis, and the case fatality rate for nonopportunistic infections may be greater than in non-HIV-infected children. In "developing" countries, with limited access to HAART, the natural history of HIV infection has altered very little, with the majority of infected children dying from either opportunistic or nonopportunistic disease before 3 yrs of age.

CONCLUSION

Pediatric HIV infection is not a homogeneous condition in the era of HAART. Susceptibility to sepsis, morbidity, and mortality differ according to stage of disease, access to HAART, and virologic and immunologic response to treatment. These issues should be considered if HIV-infected children are to be enrolled and stratified in clinical trials.

Nontyphoidal salmonella bacteremia and pneumonia as the initial manifestation of human immunodeficiency virus infection in a four-year-old child

This report describes the case of a 4-year-old human immunodeficiency virus (HIV)-infected girl with Salmonella typhimurium bacteremia and pneumonia. The girl presented with a history of fever for 1 month and mild pulmonary symptoms. Subsequent studies revealed previously undiagnosed HIV disease.

Catheter-related bloodstream infections in HIV-infected patients

Bloodstream infections (BSI) constitute a significant public health problem and represent an important cause of morbidity and mortality in hospitalized patients, with an approximate incidence of one episode per hundred hospital admissions. Studies on BSI in HIV+ patients have identified central venous catheters (CVC) as a risk factor, with an attributable mortality rate of 10-20%. The long-term CVC-related infection risk appeared to be 5 to 10-fold higher with respect to the infection rates among HIV- patients. CVC associated infection rate ranges from 1.3 to 12 infections per 1,000 catheter-days. Staphylococcus aureus is the most common etiologic agent causative of CVC-related BSI, likely the result of the high skin and nasal carriage of this organism among HIV+ patients, mostly intravenous drug users. Coagulase-negative staphylococci are also frequently identified as cause of CVC-related BSI, likely the result of breaches in infection control measures and in antiseptic technique during CVC management. Treating bacteremia without catheter removal would be optimal, but the reported efficacy of systemic antibiotic therapy alone is only 25-32%. Conversely, recent studies have shown that, using an antibiotic-lock procedure, up to 90% of HIV-infected and uninfected patients achieved complete eradication of catheter-related BSIs without catheter removal. Clinical trials using new materials such as covalently linked heparin on the CVC surface, electrically charged CVC, novel topical agents that interfere with bacterial colonization, antiadhesin molecules and agents that block the gene expression involved in the biofilm formation, are all needed to reduce the high catheter-related infection risk among HIV+ patients.

Enterobacter spp. infections complicating the course of HIV disease

Through a retrospective review of clinical and laboratory data of 2517 consecutive patients with HIV disease hospitalized since 1991, 13 patients were identified (0.52%), who suffered from a confirmed Enterobacter spp. infection (urinary tract disease in 7 cases, sepsis in 4 patients, and pneumonia in 2 cases). A severe immunodeficiency was recognized in all cases, as expressed by a mean CD4+ lymphocyte count <60 cells/microL, and frequently, a prior diagnosis of AIDS. Bloodstream infection proved linked to a lower mean CD4+ cell count, a more frequent occurrence of leukopenia-neutropenia, and nosocomial origin of the infecting pathogen. Hospital-acquired Enterobacter spp. disease was more frequent than community-acquired, and was significantly associated with leukopenia-neutropenia, and a diagnosis of AIDS. Antibiotic susceptibility assays showed a resistance rate to ampicillin and cephalothin involving >90% of tested strains, and a higher (but varied) sensitivity to other beta-lactams, aminoglycosides, fluoroquinolones, and cotrimoxazole. Adequate chemotherapy provided clinical and bacteriological success in all evaluated patients, in the absence of mortality or relapses. Only 34 episodes of HIV-associated Enterobacter spp. infection have been reported to date in 11 different literature studies. Our data point out that also Enterobacter spp. organisms may have an appreciable pathogenic potential in patients with HIV disease, especially in those with a low CD4+ lymphocyte count, leukopenia-neutropenia, who are hospitalized. Despite the unpredictable antibiotic susceptibility profile of these organisms, HIV-related Enterobacter spp. disease may be properly managed through rapid identification and timely and appropriate antimicrobial treatment.

Antimicrobial resistance in the chronically critically ill patient

Infection caused by organisms resistant to conventional antimicrobial therapy is an emerging problem of global proportions. This article describes the epidemiology of infections caused by resistant organisms in chronically critically ill patients and explores factors and mechanisms that lead to the development of resistance. Specific organisms and strategies for the treatment and control of these resistance organisms are discussed.

Oxygen-dependent anti-Salmonella activity of macrophages

Numerous observations have established a crucial role for phagocytic cells in host resistance to Salmonella. Activated macrophages rely on a complex array of oxygen-dependent antimicrobial molecules to inhibit or kill intracellular Salmonella. An initial oxidative bactericidal phase, which is dependent on the respiratory burst phagocyte oxidase (phox) is succeeded by a prolonged nitrosative bacteriostatic phase, which is dependent on inducible nitric oxide synthase (iNOS). The sequential contribution of phox and iNOS to anti-Salmonella innate immunity has been demonstrated both in vitro and in vivo. The temporal progression from the predominant production of reactive oxygen species to the production of nitrogen oxides could optimize the initial reduction in microbial burden while minimizing the immunopathological consequences of the host inflammatory response.