Alexandra Swartzman

Predicting mortality from HIV-associated Pneumocystis pneumonia at illness presentation: an observational cohort study

Background: Although the use of antiretroviral therapy has led to dramatic declines in AIDS-associated mortality, Pneumocystis pneumonia (PCP) remains a leading cause of death in HIV-infected patients. Objectives: To measure mortality, identify predictors of mortality at time of illness presentation and derive a PCP mortality prediction rule that stratifies patients by risk for mortality. Methods: An observational cohort study with case note review of all HIV-infected persons with a laboratory diagnosis of PCP at San Francisco General Hospital from 1997 to 2006. Results: 451 patients were diagnosed with PCP on 524 occasions. In-hospital mortality was 10.3%. Multivariate analysis identified five significant predictors of mortality: age (adjusted odds ratio (AOR) per 10-year increase, 1.69; 95% CI 1.08 to 2.65; p = 0.02); recent injection drug use (AOR 2.86; 95% CI 1.28 to 6.42; p = 0.01); total bilirubin >0.6 mg/dl (AOR 2.59; 95% CI 1.19 to 5.62; p = 0.02); serum albumin <3 g/dl (AOR 3.63; 95% CI 1.72–7.66; p = 0.001); and alveolar–arterial oxygen gradient ⩾50 mm Hg (AOR 3.02; 95% CI 1.41 to 6.47; p = 0.004). Using these five predictors, a six-point PCP mortality prediction rule was derived that stratifies patients according to increasing risk of mortality: score 0–1, 4%; score 2–3, 12%; score 4–5, 48%. Conclusions: The PCP mortality prediction rule stratifies patients by mortality risk at the time of illness presentation and should be validated as a clinical tool.

Pneumocystis colonisation is common among hospitalised HIV infected patients with non-Pneumocystis pneumonia

Background: When Pneumocystis DNA is recovered from respiratory specimens of patients without Pneumocystis pneumonia (PCP), patients are said to be colonised with Pneumocystis, although the significance of this state is unknown. Understanding risk factors for and outcomes of colonisation may provide insights into the life cycle and transmission dynamics of Pneumocystis jirovecii. Methods: We performed a cross sectional study of the prevalence and clinical predictors of Pneumocystis colonisation in 172 HIV infected, PCP negative inpatients undergoing diagnostic evaluation of 183 episodes of pneumonia at either the Medical Center of Louisiana at New Orleans between 2003 and 2005 or San Francisco General Hospital between 2000 and 2005. DNA was extracted from sputum and bronchoalveolar lavage specimens and amplified using a nested PCR assay at the mitochondrial large subunit (18S) ribosomal RNA locus. Colonisation was deemed present if Pneumocystis DNA was identified by both gel electrophoresis and direct DNA sequencing. Results: 68% (117/172) of all patients were colonised with Pneumocystis. No strong associations with colonisation were identified for any demographic factors. Among clinical factors, having a CD4+ T cell count ⩽50 cells/μl (unadjusted OR 2.4, 95% CI 1.09 to 5.48; p = 0.031) and using PCP prophylaxis (unadjusted OR 0.55, 95% CI 0.29 to 1.07; p = 0.077) were associated with Pneumocystis colonisation, although the latter association may have been due to chance. After adjustment for CD4+ T cell count, use of PCP prophylaxis was associated with a decreased odds of colonisation (adjusted OR 0.45, 95% CI 0.21 to 0.98; p = 0.045). 11 patients who were colonised were subsequently readmitted for evaluation of a second episode of pneumonia; three were found to be colonised again, but none had PCP. Conclusions: The majority of hospitalised HIV infected patients with non-PCP pneumonia are colonised with Pneumocystis. Failure to use co-trimoxazole prophylaxis and severe immunosuppression are associated with an increase in the odds of colonisation. Pneumocystis colonisation among hospitalised patients does not commonly lead to PCP.

Healthcare Worker Occupation and Immune Response to Pneumocystis jirovecii

Humans may be a reservoir for this pathogen and transmit it from person to person.

Environmental Risk Factors for Pneumocystis Pneumonia Hospitalizations in HIV Patients

BACKGROUND Pneumocystis pneumonia (PcP) is the second leading cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected patients in the United States. Although the host risk factors for the development of PcP are well established, the environmental (climatological, air pollution) risk factors are poorly understood. The major goal of this study was to determine the environmental risk factors for admissions of HIV-positive patients with PcP to a single medical center. METHODS Between 1997 and 2008, 457 HIV-positive patients with microscopically confirmed PcP were admitted to the San Francisco General Hospital. A case-crossover design was applied to identify environmental risk factors for PcP hospitalizations. Climatological and air pollution data were collected from the Environmental Protection Agency and Weather Warehouse databases. Conditional logistic regression was used to evaluate the association of each environmental factor and PcP hospital admission. RESULTS Hospital admissions were significantly more common in the summer than in the other seasons. Increases in temperature and sulfur dioxide levels were independently associated with hospital admissions for PcP, but the effects of sulfur dioxide were modified by increasing carbon monoxide levels. CONCLUSIONS This study identifies both climatological and air pollution constituents as independent risk factors for hospitalization of HIV-positive patients with PcP in San Francisco. Thus, the environmental effects on PcP are more likely complex than previously thought. Further studies are needed to understand how these factors exert their effects and to determine if these factors are associated with PcP in other geographic locations.

A hydrophilic-interaction chromatography tandem mass spectrometry method for quantitation of serum s-adenosylmethionine in patients infected with human immunodeficiency virus.

BACKGROUND s-Adenosylmethionine (SAM)1 has been suggested as a diagnostic test and surrogate marker for Pneumocystis jirovecii pneumonia (PCP) in HIV-positive patients. In this study, we report a robust hydrophilic-interaction liquid chromatography tandem mass spectrometry (LC-MS/MS) assay that can be used to quantitate serum SAM in clinical laboratories. METHODS Proteins in serum samples were precipitated using trichloroacetic acid. The supernatant was separated after centrifugation. D3d3-SAM was added as the internal standard. SAM and d3-SAM were extracted using a mixed-mode cation exchange column. Extracts were dried under nitrogen and reconstituted in H2O and acetonitrile (1:9, vol:vol). HPLC-tandem mass spectrometry analysis was performed with a silica column and multiple reaction monitoring for SAM and d3-SAM. RESULTS The limit of quantitation (LOQ) for SAM was 10 ng/mL. The assay was linear between 10 and 500 ng/mL. Intra-assay coefficient of variation (CV) was 8% and inter-assay CV was 17% at the LOQ. Turnaround time for each specimen was approximately 1 h. Using this method, we found that serum SAM concentration was correlated with fasting status, especially methionine intake. We also measured acute and convalescent serum SAM levels of 8 HIV-positive patients with PCP and non-PCP pneumonia. SAM concentrations in convalescent samples were significantly increased compared to acute levels only in patients with PCP. CONCLUSIONS The LC-MS/MS method had sufficient analytical sensitivity for detecting low levels of SAM found in HIV-infected patients and can be used for quantitative measurements in a clinical laboratory. This method facilitates research and possible clinical application of SAM as a marker for PCP.

Severity and outcomes of Pneumocystis pneumonia in patients newly diagnosed with HIV infection: An observational cohort study

It is unclear whether patients who are unaware of their HIV infection have different severity or outcomes of Pneumocystis pneumonia (PCP) compared to patients who have been previously diagnosed with HIV. In this retrospective observational cohort study of consecutive HIV-infected patients with microscopically diagnosed PCP at San Francisco General Hospital between 1997 and 2006, 121 of 522 patients (23%) were unaware of their HIV infection prior to their diagnosis of PCP. The proportion of patients with concurrently diagnosed HIV and PCP each year remained unchanged during the study period. Patients with newly diagnosed HIV had a significantly higher alveolar-arterial oxygen gradient at presentation (median 51 vs 45 mm Hg, p =0.03), but there were no differences in mortality, frequency of mechanical ventilation, or admission to intensive care compared to patients with previously diagnosed HIV infection. In multivariate analysis, patients who reported a sexual risk factor for HIV infection were more likely to be newly diagnosed with HIV than patients who reported injection drug use as their only HIV risk factor (odds ratio = 3.14, 95% CI 1.59–6.18, p=0.001). This study demonstrates a continued need for HIV education and earlier HIV testing, particularly in patients with high-risk sexual behavior.

Dihydropteroate synthase mutations in Pneumocystis pneumonia: Impact of applying different definitions of prophylaxis, mortality endpoints and mutant in a single cohort

Pneumocystis jirovecii dihydropteroate synthase (DHPS) gene mutations are well-reported. Although sulfa prophylaxis generally is associated with DHPS mutant infection, whether mutant infection is associated with poorer clinical outcomes is less clear. The differing definitions of sulfa prophylaxis and the different mortality endpoints used in these studies may be one explanation for the conflicting study results. Applying different definitions of prophylaxis, mortality endpoints and DHPS mutant to 301 HIV-infected patients with Pneumocystis pneumonia, we demonstrate that prophylaxis, irrespective of definition, increased the risk of infection with pure mutant (any prophylaxis: AOR 4.00, 95% CI: 1.83-8.76, P < 0.001) but not mixed genotypes (any prophylaxis: AOR 0.78, 95% CI: 0.26-2.36, P = 0.65). However, infection with mutant DHPS, irrespective of definition, was not associated with increased mortality (all-cause or PCP death) at the three time-intervals examined (all P > 0.05). Future studies should standardize key variables associated with DHPS mutant infection as well as examine DHPS mutant subtypes (pure mutant vs. mixed infections) - perhaps even individual DHPS mutant genotypes - so that data can be pooled to better address this issue.

Pneumocystis jirovecii Dihydropteroate Synthase Gene Mutations and Human Immunodeficiency Virus‐Associated Pneumocystis Pneumonia

LAURENCE HUANG, DAVID A. WELSH, ROBERT F. MILLER, C. BEN BEARD, GENA G. LAWRENCE, MELISSA FOX, ALEXANDRA SWARTZMAN, MATTHEW R. BENSLEY, DENISE CARBONNET, J. LUCIAN DAVIS, AMY CHI, BECKY J. YOO and JEFFREY L. JONES HIV/AIDS Division, Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California 94110, and Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California 94110, and Pulmonary and Critical Care Medicine, Medical Center of Louisiana at New Orleans, Louisiana State University Health Sciences Center, New Orleans, Los Angeles, and Department of Population Sciences and Primary Care, Centre for Sexual Health and HIV Research, Royal Free and University College Medical School, University College London, London, United Kingdom, and Division of Vector-Borne Infectious Diseases, Bacterial Diseases Branch, U.S. Centers for Disease Control and Prevention, Fort Collins, Colorado, and Division of Parasitic Diseases, National Center for Infectious Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia

Antibody Responses against Pneumocystis jirovecii in Health Care Workers Over Time

In a previous cross-sectional study, we showed that clinical staff working in a hospital had significantly higher antibody levels than nonclinical staff to Pneumocystis jirovecii. We conducted a longitudinal study, described here, to determine whether occupation and self-reported exposure to a patient with P. jirovecii pneumonia were associated with antibody levels to P. jirovecii over time. Baseline and quarterly serum specimens were collected and analyzed by using an ELISA that targeted different variants of the Pneumocystis major surface glycoprotein (MsgA, MsgB, MsgC1, MsgC3, MsgC8, and MsgC9). Clinical staff had significantly higher estimated geometric mean antibody levels against MsgC1 and MsgC8 than did nonclinical staff over time. Significant differences were observed when we compared the change in antibody levels to the different MsgC variants for staff who were and were not exposed to P. jirovecii pneumonia–infected patients. MsgC variants may serve as indicators of exposure to P. jirovecii in immunocompetent persons.