Sulfa use, dihydropteroate synthase mutations, and Pneumocystis jirovecii pneumonia

Clinical significance of mutations in dihydropteroate synthase in Pneumocystis jirovecii pneumonia among non-HIV-infected patients

BACKGROUND

Dihydropteroate synthase (DHPS) mutations may be associated with trimethoprim-sulfamethoxazole resistance in Pneumocystis jirovecii pneumonia (PCP) and worse clinical outcomes. However, the clinical significance of DHPS mutations in PCP among non-human immunodeficiency virus (HIV)-infected patients remains unclear.

METHODS

Patients with PCP in three tertiary referral hospitals in Taiwan between 2016 and 2020 were retrospectively enrolled. Two point mutations, Thr55Ala and Pro57Ser, in the DHPS protein were analysed. Patients with invalid DHPS mutations in the respiratory specimen, chronic respiratory failure, receiving endotracheal intubation for surgical intervention, HIV infection, Pneumocystis jirovecii colonisation, and no lactate dehydrogenase (LDH) data were excluded. The primary outcome was 30-day survival.

RESULTS

A total of 215 patients were analysed. Mutants inside DHPS were found in 78 patients (36.3%) and 68 patients (31.6%) died within 30 days. A total of 214 patients (99.5%) received trimethoprim-sulfamethoxazole as the first-line treatment. The rates of mechanical ventilation, 30-day, and in-hospital mortality were similar between wild-type and mutant DHPS PCP. After adjusting for important confounders, LDH > 500 µ/L (adjusted hazard ratio [aHR] = 2.448, P = 0.001), pneumonia severity index > 135 mg/dL (aHR = 1.689, P = 0.049), and having solid tumours (aHR = 1.832, P = 0.034) were independently associated with higher mortality. In subgroup analysis, mutant DHPS PCP patients had less 30-day mortality among patients aged > 65 years (P = 0.049), with lymphopenia (P = 0.040), and those without solid tumour (P = 0.045).

CONCLUSIONS

In non-HIV-infected PCP, point mutants inside DHPS may not be associated with trimethoprim-sulfamethoxazole treatment outcomes. Further prospective large-scale studies are warranted.

OUP accepted manuscript

The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.

Update on Dihydropteroate Synthase (DHPS) Mutations in Pneumocystis jirovecii

A Pneumocystis jirovecii is one of the most important microorganisms that cause pneumonia in immunosupressed individuals. The guideline for treatment and prophylaxis of Pneumocystis pneumonia (PcP) is the use of a combination of sulfa drug-containing trimethroprim and sulfamethoxazole. In the absence of a reliable method to culture Pneumocystis, molecular techniques have been developed to detect mutations in the dihydropteroate synthase gene, the target of sulfa drugs, where mutations are related to sulfa resistance in other microorganisms. The presence of dihydropteroate synthase (DHPS) mutations has been described at codon 55 and 57 and found almost around the world. In the current work, we analyzed the most common methods to identify these mutations, their geographical distribution around the world, and their clinical implications. In addition, we describe new emerging DHPS mutations. Other aspects, such as the possibility of transmitting Pneumocystis mutated organisms between susceptible patients is also described, as well as a brief summary of approaches to study these mutations in a heterologous expression system.

Drug-Resistant Fungi: An Emerging Challenge Threatening Our Limited Antifungal Armamentarium

The high clinical mortality and economic burden posed by invasive fungal infections (IFIs), along with significant agricultural crop loss caused by various fungal species, has resulted in the widespread use of antifungal agents. Selective drug pressure, fungal attributes, and host- and drug-related factors have counteracted the efficacy of the limited systemic antifungal drugs and changed the epidemiological landscape of IFIs. Species belonging to Candida, Aspergillus, Cryptococcus, and Pneumocystis are among the fungal pathogens showing notable rates of antifungal resistance. Drug-resistant fungi from the environment are increasingly identified in clinical settings. Furthermore, we have a limited understanding of drug class-specific resistance mechanisms in emerging Candida species. The establishment of antifungal stewardship programs in both clinical and agricultural fields and the inclusion of species identification, antifungal susceptibility testing, and therapeutic drug monitoring practices in the clinic can minimize the emergence of drug-resistant fungi. New antifungal drugs featuring promising therapeutic profiles have great promise to treat drug-resistant fungi in the clinical setting. Mitigating antifungal tolerance, a prelude to the emergence of resistance, also requires the development of effective and fungal-specific adjuvants to be used in combination with systemic antifungals.

Pneumocystis pneumonia in the twenty-first century: HIV-infected versus HIV-uninfected patients

Introduction: Pneumocystis pneumonia (PcP) has classically been described as a serious complication in patients infected with the human immunodeficiency virus (HIV). However, the emerging number of conditions associated with immunosuppression has led to its appearance in other patient populations. Areas covered: This article reviews the most recent publications on PcP in the HIV-infected and HIV-uninfected population, focusing on epidemiology, diagnostic, therapy and prevention. The data discussed here were mainly obtained from a non-systematic review using Medline and references from relevant articles including randomized clinical trials, meta-analyses, observational studies and clinical reviews. Expert opinion: The growing incidence of Pneumocystis infection in the HIV-uninfected population suggests the need for new global epidemiological studies in order to identify the true scale of the disease in this population. These data would allow us to improve diagnosis, therapeutic strategies, and clinical management. It is very important that both patients and physicians realize that HIV-uninfected patients are at risk of PcP and that rapid diagnosis and early initiation of treatment are associated with better prognosis. Currently, in-hospital mortality rates are very high: 15% for HIV-infected patients and 50% in some HIV-uninfected patients. Therefore, adequate preventive measures should be implemented to avoid the high mortality rates seen in recent decades.

Combination therapy with trimethoprim-sulfamethoxazole and caspofungin in a case of severe pneumocystis pneumonia

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Bactrim failure adverse effects.

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Alternative echinocandin target.

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Combination echinocandin therapy.

Trimethoprim-sulfamethoxazole (TMP-SMX, co-trimoxazole, or bactrim) has been the standard first-line treatment against Pneumocystis jirovecii pneumonia (PCP) for decades. However, adverse effects and cases of treatment failure have led to a search for alternative agents. We present a case of a 50 year old immune compromised female whose course of PCP did not improve until Caspofungin was added to TMP-SMX.

A Molecular Window into the Biology and Epidemiology of Pneumocystis spp

Pneumocystis, a unique atypical fungus with an elusive lifestyle, has had an important medical history. It came to prominence as an opportunistic pathogen that not only can cause life-threatening pneumonia in patients with HIV infection and other immunodeficiencies but also can colonize the lungs of healthy individuals from a very early age. The genus Pneumocystis includes a group of closely related but heterogeneous organisms that have a worldwide distribution, have been detected in multiple mammalian species, are highly host species specific, inhabit the lungs almost exclusively, and have never convincingly been cultured in vitro, making Pneumocystis a fascinating but difficult-to-study organism. Improved molecular biologic methodologies have opened a new window into the biology and epidemiology of Pneumocystis. Advances include an improved taxonomic classification, identification of an extremely reduced genome and concomitant inability to metabolize and grow independent of the host lungs, insights into its transmission mode, recognition of its widespread colonization in both immunocompetent and immunodeficient hosts, and utilization of strain variation to study drug resistance, epidemiology, and outbreaks of infection among transplant patients. This review summarizes these advances and also identifies some major questions and challenges that need to be addressed to better understand Pneumocystis biology and its relevance to clinical care.

High Prevalence of Pneumocystis jirovecii Dihydropteroate Synthase Gene Mutations in Patients with a First Episode of Pneumocystis Pneumonia in Santiago, Chile, and Clinical Response to Trimethoprim-Sulfamethoxazole Therapy

Mutations in the dihydropteroate synthase (DHPS) gene of Pneumocystis jirovecii are associated with the failure of sulfa prophylaxis. They can develop by selection in patients receiving sulfa drugs or be acquired via person-to-person transmission. DHPS mutations raise concern about the decreasing efficacy of sulfa drugs, the main available therapeutic tool for Pneumocystis pneumonia (PCP). The prevalence of Pneumocystis DHPS mutations was examined in Pneumocystis isolates from 56 sulfa-prophylaxis-naive adults with a first episode of PCP from 2002 to 2010 in Santiago, Chile. Their clinical history was reviewed to analyze the effect of these mutations on response to trimethoprim-sulfamethoxazole (TMP-SMX) therapy and outcome. Mutant genotypes occurred in 22 (48%) of 46 HIV-infected patients and in 5 (50%) of 10 HIV-uninfected patients. Compared to patients with a wild-type genotype, those with mutant genotypes were more likely to experience sulfa treatment-limiting adverse reactions and to have a twice-longer duration of mechanical ventilation if mechanically ventilated. Specific genotypes did not associate with death, which occurred in none of the HIV-infected patients and in 50% of the non-HIV-infected patients. Chile has a high prevalence of DHPS mutations, which were presumably acquired through interhuman transmission because patients were not on sulfa prophylaxis. These results contrast with the low prevalence observed in other Latin American countries with similar usage of sulfa drugs, suggesting that additional sources of resistant genotypes may be possible. The twice-longer duration of mechanical ventilation in patients with mutant DHPS genotypes suggests a decreased efficacy of TMP-SMX and warrants collaborative studies to assess the relevance of DHPS mutations and further research to increase therapeutic options for PCP.

Evaluation of a new commercial real-time PCR assay for diagnosis of Pneumocystis jirovecii pneumonia and identification of dihydropteroate synthase (DHPS) mutations

The PneumoGenius® real-time PCR assay is a new commercial multiplex real-time PCR method, which detects the Pneumocystis mitochondrial ribosomal large subunit (mtLSU) and two dihydropteroate synthase (DHPS) point mutations. To evaluate the clinical performance of this new real-time PCR assay we tested 120 extracted DNA samples from bronchoalveolar lavage specimens. These set of extracted DNA samples had already tested positive for Pneumocystis and patients had been classified in probable and unlikely PCP in a previous study. To evaluate de accuracy of the DHPS mutant's identification, an "in house" PCR and sequencing was performed. The sensitivity and specificity of PneumoGenius® PCR in discriminating between probable and unlikely Pneumocystis pneumonia (PCP) were 70% and 82% respectively. PneumoGenius® PCR was able to genotype more samples than "in house" DHPS PCR and sequencing. The same DHPS mutations were observed by both methods in four patients: two patients with a single mutation in position 171 (Pro57Ser) and two patients with a double mutation in position 165 (Thr55Ala) and in position 171 (Pro57Ser). A low rate of P. jirovecii (4.5%) harboring DHPS mutations was found, comparable to rates observed in other European countries. The PneumoGenius® real-time PCR is a suitable real-time PCR for PCP diagnosis and detection of DHPS mutants. The added value of DHPS mutation identification can assist in understanding the role of these mutations in prophylaxis failure or treatment outcome.

Prophylaxis for Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients

BACKGROUND

Pneumocystis pneumonia (PCP) is a disease affecting immunocompromised patients. PCP among these patients is associated with significant morbidity and mortality.

OBJECTIVES

To assess the effectiveness of PCP prophylaxis among non-HIV immunocompromised patients; and to define the type of immunocompromised patient for whom evidence suggests a benefit for PCP prophylaxis.

SEARCH METHODS

Electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 1), MEDLINE and EMBASE (to March 2014), LILACS (to March 2014), relevant conference proceedings; and references of identified trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing prophylaxis with an antibiotic effective against PCP versus placebo, no intervention, or antibiotic(s) with no activity against PCP; and trials comparing different antibiotics effective against PCP among immunocompromised non-HIV patients. We only included trials in which Pneumocystis infections were available as an outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias in each trial and extracted data from the included trials. We contacted authors of the included trials to obtain missing data. The primary outcome was documented PCP infections. Risk ratios (RR) with 95% confidence intervals (CI) were estimated and pooled using the random-effects model.

MAIN RESULTS

Thirteen trials performed between the years 1974 and 2008 were included, involving 1412 patients. Four trials included 520 children with acute lymphoblastic leukemia and the remaining trials included adults with acute leukemia, solid organ transplantation or autologous bone marrow transplantation. Compared to no treatment or treatment with fluoroquinolones (inactive against Pneumocystis), there was an 85% reduction in the occurrence of PCP in patients receiving prophylaxis with trimethoprim/sulfamethoxazole, RR of 0.15 (95% CI 0.04 to 0.62; 10 trials, 1000 patients). The evidence was graded as moderate due to possible risk of bias. PCP-related mortality was also significantly reduced, RR of 0.17 (95% CI 0.03 to 0.94; nine trials, 886 patients) (low quality of evidence due to possible risk of bias and imprecision), but in trials comparing PCP prophylaxis against placebo or no treatment there was no significant effect on all-cause mortality (low quality of evidence due to imprecision). Occurrence of leukopenia or neutropenia and their duration were not reported consistently. No significant differences in overall adverse events or events requiring discontinuation were seen comparing trimethoprim/sulfamethoxazole to no treatment or placebo (four trials, 470 patients, moderate quality evidence). No differences between once daily versus thrice weekly trimethoprim/sulfamethoxazole were seen (two trials, 207 patients).

AUTHORS' CONCLUSIONS

Given an event rate of 6.2% in the control groups of the included trials, prophylaxis for PCP using trimethoprim/sulfamethoxazole is highly effective among non-HIV immunocompromised patients, with a number needed to treat to prevent PCP of 19 patients (95% CI 17 to 42). Prophylaxis should be considered for patients with a similar baseline risk of PCP.

Update on pulmonary Pneumocystis jirovecii infection in non-HIV patients

Pneumocystis jirovecii is the only fungus of its kind to be pathogenic in humans. It is primarily responsible for pneumonia (PJP). The key to understanding immune defences has focused on T-cells, mainly because of the HIV infection epidemic. Patients presenting with PJP all have a CD4 count below 200/mm(3). The introduction of systematic primary prophylaxis and the use of new anti-retroviral drugs have significantly reduced the incidence of this disease in the HIV-infected population, mainly in developed countries. The increasingly frequent use of corticosteroids, chemotherapy, and other immunosuppressive drugs has led to an outbreak of PJP in patients not infected by HIV. These patients presenting with PJP have more rapid and severe symptoms, sometimes atypical, leading to delay the initiation of a specific anti-infective therapy, sometimes a cause of death. However, the contribution of new diagnostic tools and a better understanding of patients at risk should improve their survival.

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.

Low prevalence of Pneumocystis pneumonia (PCP) but high prevalence of pneumocystis dihydropteroate synthase (dhps) gene mutations in HIV-infected persons in Uganda

Pneumocystis jirovecii pneumonia (PCP) is an important opportunistic infection in patients infected with HIV, but its burden is incompletely characterized in those areas of sub-Saharan Africa where HIV is prevalent. We explored the prevalence of both PCP in HIV-infected adults admitted with pneumonia to a tertiary-care hospital in Uganda and of putative P. jirovecii drug resistance by mutations in fungal dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr). In 129 consecutive patients with sputum smears negative for mycobacteria, 5 (3.9%) were diagnosed with PCP by microscopic examination of Giemsa-stained bronchoalveolar lavage fluid. Concordance was 100% between Giemsa stain and PCR (dhps and dhfr). PCP was more prevalent in patients newly-diagnosed with HIV (11.4%) than in patients with known HIV (1.1%; p = 0.007). Mortality at 2 months after discharge was 29% overall: 28% among PCP-negative patients, and 60% (3 of 5) among PCP-positive patients. In these 5 fungal isolates and an additional 8 from consecutive cases of PCP, all strains harbored mutant dhps haplotypes; all 13 isolates harbored the P57S mutation in dhps, and 3 (23%) also harbored the T55A mutation. No non-synonymous dhfr mutations were detected. PCP is an important cause of pneumonia in patients newly-diagnosed with HIV in Uganda, is associated with high mortality, and putative molecular evidence of drug resistance is prevalent. Given the reliability of field diagnosis in our cohort, future studies in sub-Saharan Africa can investigate the clinical impact of these genotypes.

Outcomes and duration of Pneumocystis jiroveci pneumonia therapy in infants with severe combined immunodeficiency

This retrospective review of patients with severe combined immunodeficiency and Pneumocystis jiroveci pneumonia (PCP) evaluated the relationship between duration of therapy to treat PCP and overall survival. We found that 80% of patients receiving only 21 days of antibiotics survived to 12 months beyond hematopoietic cell transplant, whereas only 25% of patients who required longer treatment for PCP survived to stem cell engraftment.

Pneumocystis jirovecii colonization in chronic pulmonary disease

Pneumocystis jirovecii causes pneumonia in immunosuppressed individuals. However, it has been reported the detection of low levels of Pneumocystis DNA in patients without signs and symptoms of pneumonia, which likely represents colonization. Several studies performed in animals models and in humans have demonstrated that Pneumocystis induces a local and a systemic response in the host. Since P. jirovecii colonization has been found in patients with chronic pulmonary diseases it has been suggested that P. jirovecii may play a role in the physiopathology and progression of those diseases. In this report we revise P. jirovecii colonization in different chronic pulmonary diseases such us, chronic obstructive pulmonary disease, interstitial lung diseases, cystic fibrosis and lung cancer.

High prevalence of Pneumocystis jiroveci colonization among young HIV-infected patients

BACKGROUND

Pneumocystis colonization in young HIV-infected patients has been poorly studied. The aim of this study was to analyze the prevalence of P jiroveci colonization in a cohort of young HIV-infected patients.

MATERIAL AND METHODS

We designed a basal cross-sectional study in 20 young HIV-infected patients to determine the prevalence of P jiroveci colonization in oropharyngeal wash samples studied by nested polymerase chain reaction (PCR). Subsequently, patients were followed up during 50 weeks to observe the development of Pneumocystis pneumonia (PCP).

RESULTS

P jiroveci colonization was detected in eight (40%) of the 20 oropharyngeal wash samples. Genotype 85C/248C was the most frequent. After 50 weeks of follow-up, one colonized patient with advanced immunodepression developed PCP.

CONCLUSIONS

We have found a high prevalence of P jiroveci colonization in young HIV-infected patients with a major prevalence of genotype 1 (85C/248C). Further studies are necessary to clarify if Pneumocystis colonization could be a potential risk factor of developing PCP in young HIV infected patients.

High prevalence of dihydropteroate synthase mutations in Pneumocystis jirovecii isolated from patients with Pneumocystis pneumonia in South Africa

Pneumocystis jirovecii pneumonia (PCP) is an important cause of morbidity and mortality in immunocompromised patients. Sulfa-containing drugs are used for the treatment and prophylaxis of PCP. Mutations in the P. jirovecii fas gene, which encodes dihydropteroate synthase (DHPS), are associated with prior exposure to sulfa drugs, and their appearance suggests the emergence of variants with reduced sulfa susceptibility. The present study examined the prevalence of DHPS mutations in P. jirovecii strains isolated from South African patients with PCP. P. jirovecii infection was investigated by immunofluorescence microscopy and quantitative real-time PCR with respiratory specimens from 712 patients (93% of whom were >15 years of age) with suspected PCP consecutively received for the detection of P. jirovecii over 1 year. PCR amplification and sequencing of the DHPS fas gene was attempted with DNA from the P. jirovecii-positive samples. P. jirovecii infection was confirmed by immunofluorescence microscopy in 168/712 (24%) of the patients. Carriage of the fungus was revealed by real-time PCR in 17% of the patients with negative microscopy results. The P. jirovecii fas gene was successfully amplified from specimens from 151 patients and sequenced. Mutations resulting in the Thr55Ala and/or Pro57Ser amino acid substitution were detected in P. jirovecii strains from 85/151 (56%) patients. The high frequency of PCP episodes with P. jirovecii harboring DHPS mutations in South Africa indicates that populations of this fungus are evolving under the considerable selective pressure exerted by sulfa-containing antibiotics. These results, similar to previous observations of sulfa drug resistance in bacterial populations, underscore the importance of the rational use of sulfa medications either prophylactically against PCP or for the treatment of other infections.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

Pneumocystis pneumonia in children

Pneumocystis pneumonia (PCP) is a life-threatening infection in immunocompromised children with quantitative and qualitative defects in T lymphocytes. At risk are children with lymphoid malignancies, HIV infection, corticosteroid therapy, transplantation and primary immunodeficiency states. Diagnosis is established through direct examination or polymerase chain reaction (PCR) from respiratory secretions. Trimethoprim-sulphamethoxazole is used for initial therapy in most patients, while pentamidine, atovaquone, clindamycin plus primaquine, and dapsone plus trimethoprim are alternatives. Prophylaxis of high-risk patients reduces but does not eliminate the risk of PCP. Improved understanding of the pathogenesis of PCP is important for future advances against this life-threatening infection.

Pneumocystis mediates overexpression of antizyme inhibitor resulting in increased polyamine levels and apoptosis in alveolar macrophages

Pneumocystis pneumonia (PcP) is the most common opportunistic disease in immunocompromised patients. Alveolar macrophages are responsible for the clearance of Pneumocystis organisms; however, they undergo a high rate of apoptosis during PcP due to increased intracellular polyamine levels. In this study, the sources of polyamines and mechanisms of polyamine increase and polyamine-induced apoptosis were investigated. The level of ornithine decarboxylase (ODC) was elevated in alveolar macrophages, and the number of alveolar macrophages that took up exogenous polyamines was increased 20-fold during PcP. Monocytes, B lymphocytes, and CD8+ T lymphocytes that were recruited into the lung during PcP expressed high levels of ornithine decarboxylase, suggesting that these cells are sources of polyamines. Both protein and mRNA levels of antizyme inhibitor (AZI) were increased in alveolar macrophages during PcP. This AZI overexpression correlated with increased polyamine uptake by alveolar macrophages, because AZI expression knockdown decreased the polyamine uptake ability of these cells. AZI expression knockdown also decreased the apoptosis rate of alveolar macrophages. Pneumocystis organisms and zymosan A were found to induce AZI overexpression in alveolar macrophages, suggesting that beta-glucan, which is the major component of the Pneumocystis cell wall, induces AZI overexpression. The levels of mRNA, protein, and activity of polyamine oxidase were increased in alveolar macrophages during PcP, indicating that the H(2)O(2) generated during polyamine catabolism caused alveolar macrophages to undergo apoptosis. Taken together, results of this study indicate that Pneumocystis organisms induce AZI overexpression in alveolar macrophages, leading to increased polyamine synthesis and uptake and apoptosis rate of these cells.

[Pneumocystis jiroveci pneumonia during prolonged corticosteroid therapy in an immunocompetent infant]

INTRODUCTION

Pneumocystis jiroveci (PJ) infection is rare in infants and is suggestive of primary or secondary immunodeficiency. We report on a case of severe PJ pneumonia in an immunocompetent infant after prolonged corticosteroid treatment.

CASE REPORT

A 5 1/2 month-old girl presented with hypoxemic respiratory distress. Her medical record was remarkable only for a bulky parotid haemangioma, which was treated with prolonged oral corticosteroid therapy. The chest X-ray showed a mixed alveolar-interstitial pattern, and bronchoalveolar lavage revealed the presence of PJ. A favourable outcome was obtained after three weeks of intravenous trimethoprim-sulfamethoxazole treatment.

CONCLUSION

PJ infection should be suspected in infants presenting with progressive respiratory distress associated with a mixed alveolar-interstitial pattern. Its potential seriousness justifies prophylactic therapy during prolonged immunosuppressive treatment (chemotherapy, corticosteroid treatment).

Prophylaxis for Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients

BACKGROUND

Pneumocystis pneumonia (PCP) is a disease affecting immunocompromised patients. PCP among these patients is associated with significant morbidity and mortality.

OBJECTIVES

To assess the effectiveness of PCP prophylaxis among non-HIV immunocompromised patients. To define the type of immunocompromised patients for whom evidence suggests a benefit for PCP prophylaxis.

SEARCH STRATEGY

Electronic searches of The Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 1, 2007), PubMed (March 2007), LILACS (March 2007), relevant conference proceedings; references of identified trials; the first author of each included trial was contacted.

SELECTION CRITERIA

RCTs or quasi- RCTs comparing prophylaxis with an antibiotic effective against Pneumocystis versus placebo, no intervention, an antibiotic/s with no activity against Pneumocystis or another antibiotic effective against Pneumocystis for immune-compromised non-HIV patients. Only trials pre-defining Pneumocystis infections as an outcome were included.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from included trials. Relative risks (RR), with 95% confidence intervals (CI) were estimated and pooled using the random effects model.

MAIN RESULTS

Eleven trials including 1155 patients (520 children), performed between the years 1974 and 1997, were included. Compared to no treatment or treatment with fluoroquinolones (inactive against Pneumocystis), there was a 91% reduction in the occurrence of PCP in patients receiving prophylaxis with trimethoprim/sulfamethoxazole, RR 0.09 (95% CI 0.02 to 0.32), eight trials, 821 patients. No significant difference was encountered in all cause mortality, RR 0.81 (95% CI 0.27 to 2.37), five trials, 509 patients, while PCP-related mortality was significantly reduced, RR 0.17 (95% CI 0.03 to 0.94), seven trials, 701 patients. Occurrence of leukopenia, neutropenia and their duration were not reported consistently. No significant difference in any adverse event was seen comparing trimethoprim/sulfamethoxazole to no treatment/ placebo (four trials, 470 patients). No differences between once daily versus thrice weekly trimethoprim/sulfamethoxazole were seen (two trials, 207 patients).

AUTHORS' CONCLUSIONS

Given an event rate of 7.5% as in included trials' control group, prophylaxis for PCP using TMP/SMX is highly effective among non-HIV patients, with a number needed to treat of 15 patients (95% CI 13 to 20). Prophylaxis should be considered for the types of patients with hematological malignancies, bone marrow transplantation and solid organ transplantation included in these trials.

Management of patients with HIV in the intensive care unit

Because there are more than one million Americans with HIV, intensive care units continue to see frequent patients with HIV infection. In the era of highly active antiretroviral therapy, clinicians must be aware of drug toxicities and drug interactions. They must also recognize traditional opportunistic infections, as well as newer syndromes such as immune reconstitution syndrome, multicentric Castleman's disease, and primary pleural cell lymphoma.