Incidence Of Bacterial Pneumonia Research Articles

COMPREENDENDO A INTERSEÇÃO ENTRE HIV/AIDS E PNEUMONIA: UMA ANÁLISE ABRANGENTE DA LITERATURA

INTRODUCTION: The relationship between HIV/AIDS and pneumonia is complex and multifaceted. Individuals infected with HIV have a significantly higher risk of developing pneumonia, caused by both bacterial and viral agents, due to immune suppression from the virus. OBJECTIVE: To identify in the literature the relationship between HIV/AIDS and pneumonia in the context of nursing care. MATERIALS AND METHODS: This is an integrative literature review conducted in the MEDLINE, LILACS, and BDENF databases, using the descriptors: “HIV seropositivity,” “Pneumonia,” and “nursing care.” The descriptors were combined using the boolean operator AND, covering the period from 2018 to 2024. RESULTS: The study found that HIV-positive patients tend to experience a subacute progression of Pneumocystis jirovecii pneumonia (PCP), while immunocompromised patients without HIV face rapid progression, with a higher risk of respiratory failure and mortality. CT scans showed ground-glass opacities and elevated lactate dehydrogenase levels. Non-HIV patients had longer treatment delays and higher hospitalization and mortality rates. Lymphopenia, steroid use, and pneumothorax were associated with 60-day mortality. The incidence of bacterial pneumonia in people living with HIV decreased, linked to improved CD4 counts. Children with HIV showed higher mortality from coronavirus-related pneumonia. CONCLUSIONS: Future research should expand epidemiological surveillance, explore new therapies, and investigate co-infections in at-risk groups, particularly children. Additionally, strengthening public health policies and promoting prevention education are essential to improve clinical outcomes in vulnerable populations.

Epidemiology and surveillance implications of community-acquired pneumonia in children.

Community-acquired pneumonia (CAP) is the single largest infectious cause of hospitalization and death in children worldwide. With improved immunizations, the incidence of bacterial pneumonia and the number of colonized bacteria have decreased. However, respiratory viruses are still an important cause of CAP, especially as new infectious agents such severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerge. The SARS-CoV-2 virus emerged in 2019 and caused the current coronavirus disease 2019 pandemic. Therefore, it is necessary to elucidate the epidemiology and causative pathogens of CAP. Recently, the Pneumonia and Respiratory Disease Study Group, affiliated with the Korean Academy of Pediatric Allergy and Respiratory Disease, investigated the causative pathogens of respiratory infections in children hospitalized with CAP, the serotype of Streptococcus pneumoniae, and the prevalence of Mycoplasma pneumoniae with gene mutations. Antibiotic resistance and serotype test results can determine the use of empirical antibiotics. Moreover, it is possible to help develop future vaccines by comparing bacterial culture results with vaccine serotype and identifying the changes and prevalence of each serotype. Therefore, we will perform continuous national surveillance and monitor the epidemiology of respiratory pathogens in Korea and worldwide. The surveillance of these respiratory infections can play a role in monitoring the emergence of new infectious diseases such as SARS-CoV-2.

P29 A retrospective multi-centre review of antimicrobial usage in patients diagnosed with aspiration pneumonia

BackgroundOver-diagnosis of infective aspiration pneumonia is common in healthcare settings and represents a potential for misuse of antimicrobial therapy.MethodsA retrospective analysis was undertaken of all hospitalized patients treated for aspiration pneumonia within a multicentre Acute NHS Trust (April–May 2021, London, UK). Data collected included: age, initial antibiotics prescribed, duration of therapy, relevant microbiology (sputum samples or blood cultures) and chest X-ray. Treatment response was analysed including body temperature after 24 h of antimicrobials, use of oxygen support after 48 h, any escalation of antimicrobial therapy and 30 day in-hospital mortality. The study was registered as service evaluation project.ResultsIn total, 94 patients treated for aspiration pneumonia were included; median age 82 years (IQR 67–89). Co-amoxiclav monotherapy was the most frequently prescribed treatment (67/94); cephalosporins (8/94) and ciprofloxacin (4/94) were also commonly used. Duration (median) of treatment was 4.4 days (IQR 1–6.7); 32/94 patients received <48 h. Radiological evidence of consolidation, O2 support at 48 h and fever at 24 h was present in 32/94, 25/94 and 12/94 patients, respectively. A microbiological diagnosis to confirm infection was present in 12/94. Consolidation [OR 2.36 (95% CI 1.04–10.25); P = 0.037] and O2 support at 48 h [OR 3.22 (95% CI 1.02–10.25); P = 0.044], but not fever at 24 h [OR 0.94 (95% CI 0.18–4.80)], were associated with treatment escalation. No association between O2 support/fever and total duration was evident. The 30 day in-hospital mortality was 17% (16/94).ConclusionsAspiration pneumonia has high in-hospital mortality and often necessitates antibacterial treatment. The true incidence of bacterial pneumonia is unclear, and many patients may benefit from early cessation of antibacterial treatment.

Association between Hydroxychloroquine and bacterial pneumonia in rheumatic patients: A population-based propensity score matching cohort study.

Whether hydroxychloroquine (HCQ) use could reduce lesser risk of bacterial infections is unknown. We aimed to conduct a retrospective cohort propensity-matching study to investigate the association between HCQ use and the incidence of bacterial pneumonia in rheumatic patients. The Longitudinal Health Insurance Database (LHID) from Taiwan National Health Insurance Research Database (NHIRD) of 23million Taiwanese populations was used. We included patients who were newly diagnosed with rheumatic and immune disease (ICD-9-CM codes 696.0, 710, 714) within 2000-2012. HCQ users and non-users were then matched according to age, sex, urbanisation level, monthly income, comorbidities and medications in the ratio of 1:1 by the propensity score matching. Cox proportional hazard model was used to evaluate the risk of bacterial pneumonia in rheumatic patients who used HCQ and who did not use HCQ. There were total 3285 patients with rheumatic and immune disease enrolled. The cumulative incidence curve of patients with the use of HCQ sulphate had no difference to that of patient without the use of HCQ sulphate in propensity score-matched cohort, (Log-rank test: P=.5). However, patients who used HCQ sulphate for more than 1400 average use days had a lesser risk of bacterial pneumonia (adjusted HR=0.55, 95% CI=0.35, 0.89) in the cohort matched, with regarding HCQ non-users as a reference. Rheumatic patients taking HCQ had no overall significant differences of bacterial pneumonia incidences compared with rheumatic patients not taking HCQ. HCQ used more than >1400days or lupus patients using HCQ was associated with lower risk of bacterial pneumonia.

Association between Hydroxychloroquine and Bacterial Pneumonia in Rheumatic Patients: A Population-Based Propensity Score Matching Cohort Study

Background: Association between hydroxychloroquine (HCQ) and bacterial infections required to be determined. Whether hydroxychloroquinehad use could reduce lesser risk of bacterial infections are unknown. We aimed to conduct a retrospective cohort propensity-matching study to investigate the association between HCQ use and the incidence of bacterial pneumonia in rheumatic patients. Methods: The Longitudinal Health Insurance Database (LHID), a one million extract from Taiwan National Health Insurance Research Database (NHIRD) of 23 million Taiwanese populations was used. We included patients who newly diagnosed rheumatic and immune disease (ICD-9-CM codes 696.0, 710, 714) within 2000-2012.HCQ users and nonusers were then matched according to age, sex, urbanization level, monthly income, comorbidities and medications in the ratio of 1:1 by the propensity score matching. Cox proportional hazard model was used to evaluate the risk of bacterial pneumonia in rheumatic patients who used HCQ and who did not use HCQ. Results: There were total 3285 patients with rheumatic and immune disease enrolled. The cumulative incidence curve of patients with the use of HCQ sulfate had no difference to that of patient without the use of HCQ sulfate in propensity score matched cohort, (Log-rank test: p-value=0.5). However, patients used HCQ sulfate for more than 1400 average use days had a lesser risk of bacterial pneumonia (adjusted HR=0.55, 95% CI=0.35, 0.89) in the cohort matched, with regarding HCQ nonusers as a reference. Conclusion: Rheumatic patients taking HCQ had no overall significant differences of bacterial pneumonia incidences compared with rheumatic patients not taking HCQ. HCQ used more than >1400 days was associated with lower risk of bacteria pneumonia. Funding Statement: This study is supported in part by Taiwan Ministry of Health and Welfare Clinical Trial Center (MOHW109-TDU-B-212-114004), China Medical University Hospital (CMU107-ASIA-19, DMR-109-231); MOST Clinical Trial Consortium for Stroke (MOST 108-2321-B-039-003-), Tseng-Lien Lin Foundation, Taichung, Taiwan. No additional external funding was received for this study. Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: This study was approved by the Institutional Review Board of the China Medical University Hospital (CMUH104-REC2-115(AR-4)).

Vaccines from the Spanish Influenza as a firm foundation for new developments

ABSTRACT In 1914, the concept of a prophylactic vaccine, administered to a person before the disease had been contracted, was still controversial. Nevertheless, Almroth Wright tested new pneumococcus vaccines in South Africa, where the incidence of bacterial pneumonia was high amongst workers in the gold mines. He established the use of clinical trials, using around ten thousand workers, both in vaccinated and unvaccinated groups. The two groups were not matched to modern standards. Also, of course, those workers in the control unvaccinated group could not be protected: but some considered a prophylactic vaccine would exacerbate the disease. The vaccines were manufactured to contain a range of pneumococci from different clinical samples, in a serious attempt to match the microbes in the vaccine to the field bacteria. Deaths were averted by the vaccine; and side effects were noted to be minimal. Reexamination of pathology samples from the Spanish Influenza Pandemic showed quite clearly the contribution of pneumococci and streptococci to the mortality of over fifty million people in 1918–1919. The microbe causing this Pandemic was isolated in 1933, and was shown to be a true virus; this finding initiated a huge expanse and interest in influenza virus vaccines, both killed and live. A chance discovery allowed the purification of Influenza M and NP proteins then permitted the production of experimental vaccines. These vaccines were formulated to induce and B and/or T cell responses to the internal proteins. Several of these Universal Influenza Vaccines have been tested in quarantine, and have now reached Phase III trials in the community.

A Comparison of Aerobic Bacterial Culture between BAL and Induced Sputum Method on HIV-AIDS Patient with Bacterial Pneumonia CO-Infection

Background: Bacterial pneumonia is the main cause of morbidity and mortality in immunocompromised individuals. The incidence of bacterial pneumonia on HIV patients is 2,3 cases per 100 people per year. On several cases, obtaining sputum sample for cultivation to confirm bacterial pneumonia diagnosis is difficult, thus further work to gain representative sample is necessary. This can be acquired through sputum induction and bronchoscopy. This study aims to compare aerobic bacteria culture result between BAL and induced sputum NaCl 3% method.&#x0D; Method: This is a comparative analytical study which was done in UPIPI dr. Soetomo Hospital Surabaya on HIV-positive patients between 21 – 60 years old with suspected bacterial pneumonia through clinical and radiology findings. All patients went through sputum induction and BAL procedure. The sputum obtained was cultured aerobically to confirm the diagnosis of bacterial pneumonia.&#x0D; Results: There were 26 subjects with average age 40 years old and male majority (73,1%). All patients were present with coughing and breahtlessness as their chief complaint, while the general complaint was coughing with difficulty in excreting sputum. The dominant risk factor is a history of free sex. The radiologic findings were dominated with unilateral infiltrate (73,1%). Most of the FOB imaging results were normal (88,5%). The results of aerobic bacterial culture from sputum induction are: Streptococcus pneumoniae (20%), Pseudomonas aeroginosa (20%), Acinetobacter spp. (20%), while from BAL method: Klebsiella pneumoniae (25%). The different specimen-obtaining method between induced sputum and BAL method has significant result with p= 0,001 (p

The Use of Procalcitonin for Prediction of Pulmonary Bacterial Coinfection in Children With Respiratory Failure Associated With Viral Bronchiolitis.

Objectives. Viral bronchiolitis is a frequent cause of pediatric hospitalization and respiratory failure. Procalcitonin (PCT) is a biomarker used to identify serious bacterial infection and can distinguish bacterial and viral infections. Concomitant bacterial pneumonia is not rare in viral bronchiolitis and can lead to a worse clinical course. This study examined the use of PCT in pediatric patients with respiratory failure attributed to viral bronchiolitis to predict concomitant bacterial pneumonia. Methods. This prospective descriptive study evaluated children less than 4 years of age who underwent endotracheal intubation for respiratory failure due to viral bronchiolitis. PCT levels and endotracheal aspirate cultures were obtained at admission. Bacterial pneumonia was defined as at least moderate growth of a single pathogenic organism from endotracheal culture. PCT levels were evaluated in groups with and without concomitant bacterial pneumonia. Results. Thirty-five patients were enrolled between February 2013 and May 2015. All subjects tested positive for at least 1 viral pathogen by nasal wash polymerase chain reaction or enzyme immunoassay. The top viruses obtained were respiratory syncytial virus (n = 15, 42.8%) and rhinovirus (n = 8, 22.9%). The incidence of bacterial pneumonia was 60% (21/35). The PCT median was 0.93 ng/mL (interquartile range = 0.25-6.64) in the bacterial pneumonia group and 1.85 ng/mL (interquartile range = 0.28-7.94) in the nonbacterial pneumonia group. No correlation was found between PCT and bronchiolitis with bacterial coinfection (P = .74). Conclusion. Incidence of bacterial coinfection in patients with respiratory failure and viral bronchiolitis was high. PCT did not predict concomitant bacterial pneumonia in children with viral bronchiolitis.

Pulmonary Complications of HIV

Pulmonary Complications of HIV summarizes current practices for diagnosing and treating common HIV-related pulmonary complications. It is a well-written, educational work that will interest anyone managing the care of HIV-infected persons. The content and amount of information packed into this easy-to-read textbook is impressive. Each chapter is well organized and well referenced, and important concepts and definitions are laid out clearly. Since HIV/AIDS was first described, clinicians have found that the lung is the site most frequently affected and that pulmonary complications are a major cause of illness and death for HIV-infected persons. However, over the years, the discovery and use of antiretroviral therapy has increased life expectancy for HIV-infected persons, and the spectrum of infectious and noninfectious pulmonary complications has changed. For example, the incidence of opportunistic pneumoniashas declined dramatically, whereas the incidence of bacterial pneumonia has not decreased proportionately. Furthermore, noninfectious complications, such as chronic obstructive pulmonary disease and lung cancer, are increasing. It is critical for anyone managing the care of HIV-infected persons to be aware of these lung complications and understand their diagnoses, possible treatments, and prevention. Pulmonary Complications of HIV does an excellent job discussing these aspects. The authors are well-respected researchers and clinicians from throughout the world who work in the fields of pulmonary medicine and HIV-related lung diseases. The literature on HIV-related pulmonary complications is still lacking in certain areas, which most likely led to some chapters (e.g., Bronchiectasis)to be shorter and less comprehensive than others. Of the book’s 19 chapters, the first 2 discuss the global epidemiology of HIV and current antiretroviral therapy guidelines, which will be useful for clinicians who might not regularly manage the care of HIV-infected patients. The third chapter discusses pulmonary immunity, a complicated topic but one the authors explain simply by emphasizing essential concepts. The next several chapters highlight various diseases and strategies for preventing them in the field, including vaccine guidelines. In addition, the authors cover a number of other key aspects to HIV care, such as pregnancy, pediatrics, and infectious and noninfectious complications, completing a thorough review of the literature. Although infectious disease specialists and others who care for HIV-infected patients might consider the first few chapters too simplistic, the latter chapters on pulmonary complications will be relevant and instructive. Pulmonologists will find that the first few chapters discuss aspects of HIV care to which they are not readily exposed and the latter chapters provide information on the epidemiology, clinical manifestations, diagnosis, and management of common complications seen in HIV-infected persons. Pulmonary Complications of HIV does an exceptional job summarizing the major pulmonary manifestations of HIV/AIDS and discussing the progress in overall HIV treatment. Because the book itself is fairly short (265 pages), it appears to be more of a simple paperback rather than a reference textbook. Regardless, it is worthy of a spot on your bookshelf. As a clinician, educator, and researcher in the field of HIV-related lung disease, I found the book to be informative, easy to read, and a quick and simple reference to have on hand. It would be valuable to any medical trainee or clinician who manages the care of HIV-infected patients.

Invasive pneumococcal disease among HIV-1 seropositive individuals in the era of highly active antiretroviral therapy: does HIV-1 impair the macrophage host response to pneumococci?

BackgroundIn the era of highly active antiretroviral therapy, incidence of bacterial pneumonia and invasive pneumococcal disease among HIV-1 seropositive individuals is still more than 30 times higher than for seronegative individuals. Risk remains elevated in those with CD4 cell counts in the normal range. A programme of host-mediated macrophage (Mϕ) apoptosis ensures killing of Streptococcus pneumoniae when canonical phagolysosomal killing capacity is exhausted. HIV-1 infection is associated with resistance of Mϕ to apoptosis. We hypothesised that HIV-1-mediated Mϕ apoptotic resistance impairs S pneumoniae killing. MethodsThe following Mϕ models were used: healthy donor monocyte derived Mϕ (MDM) infected with HIV-1BaL (HMDM) or sham infected (SMDM), with infection confirmed with anti-p24 immunohistochemistry; and MDM treated with gp120 10–100 ng/mL (gpMDM) or vehicle (cMDM). Mϕ were challenged with opsonised type 2 S pneumonia multiplicity of infection=10 or mock-infected and apoptosis up to 20 h by observing morphological changes (counting condensed or fragmented nuclei), counting rates of positivity with the TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labelling) assay, measuring cells with hypodiploid DNA, and measuring caspase-3/7 activity. Bacterial internalisation and killing were measured by gentamicin protection assay. Data are mean and SD, and analysed by paired t test, or are median and IQR with Wilcoxon matched pairs signed rank test or Kruskal-Wallis test if non parametric. FindingsAfter S pneumoniae challenge, rates of initial S pneumoniae internalisation were similar for all MDM conditions. HMDM showed fewer apoptotic nuclei than did SMDM (19% [IQR 18–21] vs 33% [26–43], n=7, p<0·05), and smaller increases in caspase-3/7 activity and higher Mcl-1 expression on western blot after S pneumoniae challenge. Compared with cMDM, fewer gpMDM developed apoptotic nuclei after S pneumoniae challenge, which was dose dependent (cMDM 36% [IQR 30–48] vs gpMDM 20% [12–28] at 10 ng/mL and 18% [14–22] at 100 ng/mL, n=12, p<0·01, confirmed with TUNEL), and gpMDM exhibited significantly less caspase 3/7 activity (p<0·05). In gpMDM, reduced apoptosis was associated with bacterial survival. InterpretationHIV-1 infection reduces Mϕ apoptosis in response to S pneumoniae, and gp120 may be sufficient to mediate this. Apoptosis resistance may impair killing of S pneumoniae after phagocytosis and increase susceptibility to invasive pneumococcal disease in HIV-1 seropositive individuals. FundingUK Medical Research Council.

Risk factors for pneumonia caused by multidrug‐resistant Gram‐negative bacilli among liver recipients

Pneumonia caused by multidrug-resistant (MDR) Gram-negative bacilli is associated with a higher mortality rate. The appropriate empiric therapy is based on the understanding of local etiology and MDR pattern. This study was to evaluate the spectrum of Gram-negative bacilli, MDR rate, risk factors and mortality in 475 liver transplantation (LT) recipients. In the first six months after LT, the incidence of bacterial pneumonia was 21.3% (101/475). The overall infectious incidence during the first post-transplant month was 80.2%. The most frequent pneumonia isolates were Enterobacteriaceae, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus. Gram-negative bacilli accounted for 69.6% of all pneumonia pathogens. Of the main 124 Gram-negative bacilli isolates, MDR rate was 58.9%. Four risk factors for post-LT pneumonia caused by MDR Gram-negative bacilli were LT candidates with grade II-IV encephalopathy (OR 2.275, 95%CI 1.249-4.124, p = 0.006), prolonged duration of endotracheal intubation (OR 8.224, 95%CI 4.276-15.815, p = 0.013), tracheostomy (OR 4.929, 95%CI 1.099-18.308, p = 0.027) and post-LT episode(s) of reoperations (OR 10.597, 95%CI 3.726-30.134, p < 0.001). MDR Gram-negative bacterial pneumonia-related mortality was significantly higher than that because of antibiotic-susceptible bacilli (45.6% vs. 11.4%, p = 0.010). Our data suggest that pneumonia caused by MDR Gram-negative bacilli after LT is common, and associated with the severity of underlying disease, prolonged mechanical ventilation and upper abdominal surgery.

PRECLINICAL STUDY: Differential effects of ethanol on IFN‐γ‐ and TNF‐α‐producing splenic T lymphocytes in a murine model of gram‐negative pneumonia

The incidence of bacterial pneumonia is increased in alcoholic patients. Alcohol consumption has been shown to impair cytokine production. Tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) are critical for host defense against Klebsiella pneumoniae (K. pneumoniae). In order to examine the influence of alcohol on the immune response to infection, we investigated the frequency of TNF-alpha and IFN-gamma produced by splenic T-lymphocytes in a murine model of gram-negative pneumonia initiated after 8 days of alcohol treatment. Thirty-two Balb/c mice were pretreated with ethanol (3 mg/g body weight) or saline intraperitoneally over 8 days. On day 7 half of each group was administered K. pneumoniae. Mice were sacrificed 24 hours later to excise lungs and liver for histological assessment and spleens for cell isolation. IFN-gamma- and TNF-alpha-producing CD4(+) and CD8(+) lymphocytes were determined by FACS analysis. In mice with Klebsiella infection, the percentages of IFN-gamma-producing CD4(+) (P < 0.01) and CD8(+) (P < 0.01) were significantly decreased, the percentages of TNF-alpha-producing CD4(+) (P = 0.01) and CD8(+) (P < 0.01) T cells were significantly elevated after alcohol treatment compared with mice with saline treatment. The histological assessment showed an aggravation of K. pneumoniae-induced pneumonia in alcohol-treated mice. Alcohol differentially affects IFN-gamma and TNF-alpha production in Klebsiella-infected mice. Both effects obviously led to a weakened immune response as seen by increased histological damage. This suggests a role of T cells in the increased susceptibility of the alcoholic host to nosocomial infection due to inadequate cytokine response.

Antiretroviral Therapy for Children

ACCORDING TO THE UNITED NATIONS PROGRAMME on HIV/AIDS (UNAIDS) global report on human immunodeficiency virus (HIV), in 2005 more than 2.3 million children were living with HIV infection, and 380 000 children with HIV had died. Most of the children who die from HIV have severe manifestations of common childhood illnesses, such as diarrhea, malnutrition, acute respiratory tract infection, and tuberculosis. These children often die before the diagnosis of HIV infection can be made, and mortality is often attributed to a background high rate of early childhood mortality. The United States is home for a diminishing proportion of HIV-infected children, with an estimated 11 000 cases in 2005. There are 2 reasons for this decreasing population of HIV-infected children in the developed world. First, pregnant women are increasingly being offered HIV testing, and HIV-infected women are receiving antiretroviral medications sufficient to reduce transmission to a rate of approximately 1% to 2%. Second, the population of HIV-infected children is diminishing because those children who had been infected are now growing up and becoming adults, following the introduction of potent new drugs in 1996. According to a longitudinal study by the Pediatric AIDS Clinical Trials Group (PACTG 219), the mortality rate for HIVinfected children and adolescents decreased from more than 5% in 1996 to less than 1% in 1998. Similar survival benefits have been observed among adults. The impact of highly active antiretroviral therapy (HAART) on survival and quality of life among patients affected by HIV is hardly disputable, but concise objective evidence of the benefit of treatment on infectious complications in children has been lacking in the medical literature. Before the availability of HAART, opportunistic infections such as Pneumocystis jiroveci pneumonia, bacteremia, bacterial pneumonia, and fungal sepsis were significant fatal diseases in patients infected with HIV and remain so among patients not receiving therapy. In this issue of JAMA, Gona and colleagues provide objective evidence to substantiate the benefit of HAART or, more correctly, the association of HAART and opportunistic infection prophylaxis with incidence of opportunistic infections before and after the advent of HAART. In a retrospective cohort study, Gona et al compared the incidence of 29 opportunistic infections in HIV-infected children who were treated in the HAART era with the incidence among those who were treated before the availability of HAART. They found that the incidence of P jiroveci pneumonia had decreased by 14-fold, disseminated Mycobacterium avium complex by 12-fold, bacteremia by 10-fold, and bacterial pneumonia by 5-fold. These reductions in opportunistic infections occurred despite a concomitant reduction in the use of specific prophylaxis medications, suggesting that immune reconstitution rather than improved prophylaxis was primarily responsible for better outcomes. The size and diversity of the population studied allows for generalizability of the results to the US population of children with HIV infection. There were approximately 3000 children in the cohort, which constitutes about 22% of children and adolescents living with HIV in the United States. Given the diminishing population of HIV-infected children, it is unlikely that additional data will become available in this country. There were limitations with the retrospective cohort study design, which evaluated available data from a database. Some events and clinical practices changed over time and could have affected case ascertainment and overall disease incidence. Although the incidence of bacterial pneumonia was reported, the diagnosis of this problem in children is difficult, because no consistent clinical or radiographic features reliably distinguish different etiologies of pneumonia. Radiographic pneumonia may or may not be associated with bacteremia. When such an association occurs, the relationship is not always a causal one. Specific etiologic diagnosis of bacterial pneumonia can be determined by diagnostic techniques, such as lung aspirates or bronchoalveolar lavage. These procedures are highly sensitive but are seldom used because they are considered too invasive.

AIDS and the lung

More than 50% of HIV-infected patients suffer at least one respiratory episode during the course of their disease. In early HIV infection, when immune responses are relatively preserved, respiratory infections are similar to those found in the general population, though they occur more commonly. With progressive HIV-induced immunosuppression, the risk of opportunistic infections and tumours increases. Use of highly active antiretroviral therapy (HAART) has led to marked reductions in the incidence of HIV-associated opportunistic infections (including Pneumocystis jirovecii pneumonia, cytomegalovirus disease and Mycobacterium avium complex) and tumours (including Kaposi’s sarcoma). HAART has had comparatively less impact on the incidence of bacterial pneumonia, tuberculosis and non-Hodgkin’s lymphoma. Despite the development of HAART, respiratory problems continue to be a major burden of disease in those infected with HIV. Reasons for this include the limited availability of HAART worldwide (particularly in resource-poor countries), failure of prophylaxis for specific opportunistic infections, and an increasing number of patients presenting with previously undiagnosed HIV infection.

AIDS and the lung

More than 50% of HIV-infected patients suffer at least one respiratory episode during the course of their disease. In early HIV infection, when immune responses are relatively preserved, respiratory infections are similar to those found in the general population, though they occur more commonly. With progressive HIV-induced immunosuppression, the risk of opportunistic infections and tumours (Figure 1) increases. Use of highly active antiretroviral therapy (HAART) has led to marked reductions in the incidence of HIV-associated opportunistic infections (including Pneumocystis jiroveci pneumonia, cytomegalovirus disease and Mycobacteruim avium complex) and tumours (including Kaposi's sarcoma). HAART has had comparatively less impact on the incidence of bacterial pneumonia, tuberculosis (TB) and non-Hodgkin's lymphoma. Despite the development of HAART, respiratory problems continue to be a major burden of disease in those infected with HIV. Reasons for this include the limited availability of HAART worldwide (particularly in resource-poor countries), failure of sustained viral suppression in up to 50% of patients taking HAART, failure of prophylaxis for specific opportunistic infections, and an increasing number of patients presenting with previously undiagnosed HIV infection.

Impact of antiretroviral therapy on decreasing hospitalization rates of HIV-infected patients in 2001.

Effective antiretroviral therapy initially resulted in large decreases in hospitalization rates of HIV-infected patients. The goal of this study was to determine whether these gains were being maintained in 2001. A cross-sectional study of hospital admission characteristics during four time periods was performed. All patients receiving care at the HIV clinics of New York Presbyterian Hospital-Cornell Medical Center (NYPH) in New York City were included. In 1995, 883 outpatients were receiving care for HIV infection at NYPH; this increased to 1990 outpatients by 2001. Demographic and laboratory information was obtained for these outpatients, and diagnoses were recorded for all patients requiring hospitalization on at NYPH during the time periods January 1 through June 30, in 1995, 1997, 1999, and 2001. The incidence of hospital admission declined in all four time periods: 1995 (95 per 100 patient-years [pt-yr]), 1997 (48 per 100 pt-yr), 1999 (38 per 100 pt-yr, p < 0.05), and 2001 (25 per 100 pt-yr). The incidence of bacterial pneumonia and opportunistic infections (OIs) decreased in all four time periods. The median hospitalization were CD4(+) cell count for outpatients increased from 231 (1995) to 364 (2001). Important predictors of hospitalization were CD4(+) < 200, and IVDU as an HIV risk factor. Since 1995 and the introduction of highly active antiretroviral therapy, continuing increases in CD4(+) cell counts of outpatients has been reflected in persistent declines in hospitalization rates. Large decreases in OIs and pneumonia have been minimally offset by stable rates of hospital admissions for diagnoses such as hepatitis, cirrhosis, and cellulitis.

Effect of highly active antiretroviral therapy on the incidence of bacterial pneumonia in HIV-infected subjects

The aim of the study was to assess the incidence of hospital and community acquired bacterial pneumonia in HIV-infected subjects prior to and after the introduction of highly active antiretroviral therapy (HAART). We studied 266 patients with bacterial pneumonia over two separate periods, 154 in the first period and 112 in the second period. A statistically significant difference in the incidence of bacterial pneumonia in the two study periods was observed ranging from 13.1 to 8.5 episodes per 100 persons. The incidence of community-acquired bacterial pneumonia decreased from 10.7 to 7.7 ( P=0.01), while that of nosocomial episodes decreased from 2.4 to 0.8 episodes ( P=0.003). Low levels of peripheral CD 4+ cells (<100/mm 3) and intravenous drug abuse (IVDA) were significantly associated with the development of community-acquired bacterial pneumonia, while an increasing value of APACHE III score and prolonged hospitalisation increased the risk of nosocomial bacterial pneumonia in both study periods.

Protected Bronchoalveolar Lavage for the Diagnosis of HIV-Associated Pneumonia

Abstract: The aim of protected bronchoalveolar lavage (PBAL) is to improve the diagnostic yield in bacterial pneumonia by combining the high sensitivity of bronchoalveolar lavage (BAL) with the specificity of the protected specimen brush (PSB). We evaluated PBAL and PSB in patients infected with human immunodeficiency virus (HIV) known to have a high incidence of bacterial pneumonia and colonization of the tracheohronchial tree. Sixty-three consecutive episodes with symptoms suggestive of pneumonia were investigated prospeetively. A comprehensive microbiologic workup was performed, including quantitative cultures for bacterial agents. Each episode was classified as “pneumonia,” “control,” or “non-infectious infiltrates.” Fifty-one episodes were identified as pneumonia. A definite microbial etiology could be established in 34/51 (67% cases, including a bacterial etiology in 15/51 (29%). The sensitivity for definite and probable bacterial pneumonia was 13/22 (59%) for PSB and 15/22 (68%) for PBAL (p value not significant). Specificity was 8/8 (100%), but there were 4 false-positive results in cultures of PSB and in cultures of PBAL effluent in patients with infiltrates on chest radio-graphs. PBAL effluent had a significantly higher mean bacterial index and specific bacterial index than PSB (5.4 ± 4.9 vs. 3.3 ± 3.2, p < 0.01, and 5.6 ± 0.8 vs. 3.8 ± 2.1. p < 0.001). The yield for Pneumocystis carinii was 13/15 (87%). PBAL, as compared to PSB, had a similar diagnostic yield for bacterial pneumonia. Both techniques were highly specific, but the specificity may be lower in patients with abnormal chest radiographs. PBAL most accurately reflected the bacterial load of the area investigated, and also conserved the yield of BAL reported for P. carinii. PBAL is a rational technique for the diagnosis of pneumonia in patients with HIV.

Diagnostic Value of Telescoping Plugged Catheters in HIV-Infected Patients with Pulmonary Infiltrates

To assess the diagnostic value of telescoping plugged catheters (TPC) in human immunodeficiency virus (HIV)-infected patients with pulmonary infiltrates (PI), we performed a prospective clinical study in 71 episodes of fever and PI in 66 HIV-infected patients (five patients had two different episodes of fever and PI). A control group of 12 HIV-infected patients with fever and normal chest roentgenogram was also studied. In all patients and prior to antibiotic treatment (except in mechanically ventilated patients), a TPC using quantitative cultures (cutoff point established at 10(3) CFU/ml) and a bronchoalveolar lavage (BAL) sampling were performed via fiberoptic bronchoscope. The overall incidence of bacterial pneumonia in the study group was 21 percent. The TPC cultures resulted in a microbiologic diagnosis of bacterial pneumonia in eight patients (11 percent) from the study group and in one patient (8 percent) from the control group. The TPC sensitivity in diagnosing bacterial infections was 53 percent and specificity was 76 percent. Negative predictive value was 85 percent and positive predictive value was 38 percent. By means of BAL, 35 episodes from the study group and two from the control group were diagnosed as nonbacterial or mycobacterial pulmonary infections. Considering TPC and BAL together, diagnosis was performed in 42 cases of PI (59 percent). Twenty percent (17/83) of HIV-infected patients suffered from bacterial colonization of their lower airways (a TPC culture greater than or equal to 10(3) CFU/ml without clinical evidence of bacterial infection). We conclude that the combined use of TPC and BAL may be useful in HIV-infected patients with PI, since this combined use allows the proper diagnosis of bacterial and nonbacterial infections, thereby increasing the overall diagnostic accuracy. To distinguish bacterial colonization from pulmonary infection in HIV-infected patients with PI, the cutoff point of quantitative cultures of TPC may be 10(4) CFU/ml.

Bacterial Pneumonia in the HIV-Infected Patient

The incidence of bacterial pneumonia is increased in human immunodeficiency virus (HIV) infection, and bacteremia and recurrences occur frequently. Streptococcus pneumoniae and Haemophilus influenzae are the most common pathogens, but several other organisms have now been identified as etiologies. Several abnormalities in B-cells and humoral immunity, and possibly neutropenia and white blood cell dysfunction, predispose to bacterial pneumonia. Despite the severity of pneumonia in HIV infection, most patients respond well to specific antimicrobial chemotherapy. Potential preventive measures include vaccines, immunoglobulin therapy, and antimicrobial prophylaxis.