Micrococcus-associated central venous catheter infection in patients with pulmonary arterial hypertension

Acute cholangitis due to Micrococcus lylae: First case report

Micrococcus lylae, a Gram-positive bacterium of the Micrococcaceae family, is considered an opportunistic microorganism with only a few reported cases of infection. In this report, we present a case of cholangitis caused by Micrococcus lylae in a 69-year-old woman with a medical history of type 2 diabetes and a cholecystectomy performed a decade ago. She was admitted to the gastroenterology department with symptoms indicative of acute cholangitis. Abdominal computed tomography and endoscopic ultrasound showed a consistent and symmetrical dilatation and thickening of the main bile duct, containing micro stones and a macro stone in the cystic duct stump. The patient received empirical antibiotic therapy based on ceftriaxone and metronidazole. She underwent ERCP with biliary endoscopic sphincterotomy and marginal biopsy, followed by balloon-assisted manipulation to facilitate bile release and collection of an intraoperative bile fluid sample for microbiological examination to identify the pathogen and guide the treatment adjustments. The microbiological examination demonstrated the exclusive presence of Micrococcus lylae. The patient's condition notably improved, marked by the normalization of inflammatory indicators. After three days, the patient was discharged in a stable condition, continuing the antibiotic regimen with the oral administration of ciprofloxacin and metronidazole. Jaundice resolved after one week, and liver function tests were completely normalized on follow-up at one month.

Medical Emergencies in Pulmonary Hypertension

The management of acute medical emergencies in patients with pulmonary hypertension (PH) can be challenging. Patients with preexisting PH can rapidly deteriorate due to right ventricular decompensation when faced with acute physiological challenges that would usually be considered low-risk scenarios. This review considers the assessment and management of acute medical emergencies in patients with PH, encompassing both pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), acknowledging these comprise the more severe groups of PH. Management protocols are described in a systems-based approach. Respiratory emergencies include pulmonary embolism, airways disease, and pneumonia; cardiac emergencies including arrhythmia and chest pain with acute myocardial infarction are discussed, alongside PH-specific emergencies such as pulmonary artery dissection and extrinsic coronary artery compression by a dilated proximal pulmonary artery. Other emergencies including sepsis, severe gastroenteritis with dehydration, syncope, and liver failure are also considered. We propose management recommendations for medical emergencies based on available evidence, international guidelines, and expert consensus. We aim to provide advice to the specialist alongside the generalist, and emergency doctors, nurses, and acute physicians in nonspecialist centers. A multidisciplinary team approach is essential in the management of patients with PH, and communication with local and specialist PH centers is paramount. Close hemodynamic monitoring during medical emergencies in patients with preexisting PH is vital, with early referral to critical care recommended given the frequent deterioration and high mortality in this setting.

Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience

Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.

Patient perspectives on pulmonary hypertension in the United States: Burdens, expectations, and goals

Pulmonary hypertension (PH) is a life-threatening, debilitating disease caused by increased blood pressure in the pulmonary arteries. As patients living in the United States, we have unique insights into the journey from diagnosis and treatment within the US healthcare system and the significant impact that PH has on our quality of life. While there have recently been advances in PH management, there are several areas of PH care which we feel should be reassessed and improved. Commonly, diagnosis is lengthy and convoluted due to the rarity of the disease and limited knowledge of PH in primary care. There are also barriers to obtaining the right treatment and we feel that a more holistic approach to care is needed. Mental health is commonly overlooked and should be an integral part of patient care, as should elements such as nutritional advice, cardiopulmonary rehabilitation, and sexual health. PH patient associations play a key role in providing social, educational, and financial support to patients and caregivers alongside PH research and advocacy. As patients, we feel that we need to advocate for correct diagnosis, timely referral, and optimal treatment, in addition to overcoming the financial and/or administrative hurdles to obtain these. We propose several future goals to help empower patients to play an active, central role in their care and to improve all aspects of PH management. We advocate for further use of the patient voice in research and clinical development programs, including the use of patient-reported outcomes that have been developed with patient input.

Incidence of Bloodstream Infection in Patients with Pulmonary Hypertension under Intravenous Epoprostenol or Iloprost—A Multicentre, Retrospective Study

Intravenous synthetic prostacyclin analogs (iPCAs), such as epoprostenol, treprostinil and iloprost have been widely used for the treatment of pulmonary arterial hypertension (PAH). Despite having good outcomes, continuous infusion of iPCAs has been associated with some adverse effects. Bloodstream infection (BSI) is one of the most severe complications, although poorly recognized, especially under iloprost administration, which few studies have addressed. This study aimed to compare the BSI incidence rates between intravenous iloprost and epoprostenol administration. Patients with pulmonary hypertension (PH) functional class III or IV receiving intravenous iloprost or epoprostenol through Hickman catheter, between 2004 and 2019, were retrospectively selected from two PH treatment centers. From a total of 36 patients (13 for iloprost and 23 for epoprostenol), 75% (n = 27) fulfilled the PAH criteria, mainly belonging to the idiopathic group. Overall BSI rate was 1.5/1000 days of treatment (3.38 and 0.09/1000 days for iloprost and epoprostenol, respectively). Patients receiving iloprost were at a higher risk of developing BSI than those receiving epoprostenol (HR: 12.5; 95% CI: 1.569–99.092). A higher mortality rate from BSI was also identified in the iloprost group (p = 0.04). Twenty-seven patients developed BSI, with 92% of them requiring hospitalization. A total of 29 agents were found, 10 Gram-positive (mainly Staphylococcus aureus; n = 5) and 19 Gram-negative (mainly Pseudomonas aeruginosa; n = 6) bacteria. Iloprost administration was linked to a significantly higher incidence of BSI, worse prognosis, and more BSI-related deaths than epoprostenol. BSI due to Gram-negative, commensal, low-virulence bacteria was also higher in the iloprost group. In short, physicians should be aware when prescribing iPCA to guarantee their patients’ safety and best medical care.

Artemisinin and Its Derivate Alleviate Pulmonary Hypertension and Vasoconstriction in Rodent Models

Background

Pulmonary arterial hypertension (PAH) is a complex pulmonary vasculature disease characterized by progressive obliteration of small pulmonary arteries and persistent increase in pulmonary vascular resistance, resulting in right heart failure and death if left untreated. Artemisinin (ARS) and its derivatives, which are common antimalarial drugs, have been found to possess a broad range of biological effects. Here, we sought to determine the therapeutic benefit and mechanism of ARS and its derivatives treatment in experimental pulmonary hypertension (PH) models.

Methods

Isolated perfused/ventilated lung and isometric tension measurements in arteries were performed to test pulmonary vasoconstriction and relaxation. Monocrotaline (MCT) and hypoxia+Su5416 (SuHx) were administered to rats to induce severe PH. Evaluation methods of ARS treatment and its derivatives in animal models include echocardiography, hemodynamics measurement, and histological staining. In vitro, the effect of these drugs on proliferation, viability, and hypoxia-inducible factor 1α (HIF1α) was examined in human pulmonary arterial smooth muscle cells (hPASMCs).

Results

ARS treatment attenuated pulmonary vasoconstriction induced by high K⁺ solution or alveolar hypoxia, decreased pulmonary artery (PA) basal vascular tension, improved acetylcholine- (ACh-) induced endothelial-dependent relaxation, increased endothelial nitric oxide (NO) synthase (eNOS) activity and NO levels, and decreased levels of NAD(P)H oxidase subunits (NOX2 and NOX4) expression, NAD(P)H oxidase activity, and reactive oxygen species (ROS) levels of pulmonary arteries (PAs) in MCT-PH rats. NOS inhibitor, L-NAME, abrogated the effects of ARS on PA constriction and relaxation. Furthermore, chronic application of both ARS and its derivative dihydroartemisinin (DHA) attenuated right ventricular systolic pressure (RVSP), Fulton index (right ventricular hypertrophy), and vascular remodeling of PAs in the two rat PH models. In addition, DHA inhibited proliferation and migration of hypoxia-induced PASMCs.

Conclusions

In conclusion, these results indicate that treatment with ARS or DHA can inhibit PA vasoconstriction, PASMC proliferation and migration, and vascular remodeling, as well as improve PA endothelium-dependent relaxation, and eventually attenuate the development and progression of PH. These effects might be achieved by decreasing NAD(P)H oxidase generated ROS production and increasing eNOS activation to release NO in PAs. ARS and its derivatives might have the potential to be novel drugs for the treatment of PH.

Microbial contamination of the hands of healthcare providers in the operating theatre of a central hospital

Background

Effort is invested in maintaining the sterility of the operating field, but less attention is paid to potential healthcare associated infection (HAI) sources through patient contact with non-scrubbed healthcare providers (HCPs). A single microbiological assessment of hands can provide a good assessment of the potential dynamic transmission of microorganisms. The aim of this study was to identify and quantify the microbial growth on the hands of HCPs in the operating theatres of Chris Hani Baragwanath Academic Hospital.

Methods

A prospective, contextual and descriptive study design was followed. Seventy-five samples were collected using convenience sampling from an equal number of surgeons, anaesthetists and nurses. Specimens were taken using agar plates and underwent semi-quantitative analysis.

Results

All the hands of the HCPs displayed growth; 95% grew commensals and 64% grew pathogens. Eighteen commensal microorganisms and 21 pathological microorganisms were noted. Comparisons of commensal, pathological and combined levels of contamination among the three groups were not statistically significant (p = 0.061, p = 0.481, p = 0.236). No significant difference between the growth of combined microorganisms (p = 0.634) and pathological microorganisms (p = 0.499) among the groups. Surgeons had significantly more commensal growth (p = 0.041). There was no statistically significant difference between sexes (p = 0.290).

Conclusion

It was concerning that 100% of the hands of HCPs who were about to commence with the surgical list had microbial growth. These HCPs could have already been in contact with patients and equipment in the theatre environment.

Fetal meconium does not have a detectable microbiota before birth

Microbial colonization of the human intestine impacts host metabolism and immunity; however, exactly when colonization occurs is unclear. Although many studies have reported bacterial DNA in first-pass meconium samples, these samples are typically collected hours to days after birth. Here, we investigated whether bacteria could be detected in meconium before birth. Fetal meconium (n = 20) was collected by rectal swab during elective breech caesarean deliveries without labour and before antibiotics and compared to technical and procedural controls (n = 5), first-pass meconium (neonatal meconium; n = 14) and infant stool (n = 25). Unlike first-pass meconium, no microbial signal distinct from negative controls was detected in fetal meconium by 16S ribosomal RNA gene sequencing. Additionally, positive aerobic (n = 10 of 20) and anaerobic (n = 12 of 20) clinical cultures of fetal meconium (13 of 20 samples positive in at least one culture) were identified as likely skin contaminants, most frequently Staphylococcus epidermidis, and not detected by sequencing in most samples (same genera detected by culture and sequencing in 2 of 13 samples with positive culture). We conclude that fetal gut colonization of healthy term infants does not occur before birth and that microbial profiles of neonatal meconium reflect populations acquired during and after birth.

Synergistic In Vitro Antimicrobial Activity of Pomegranate Rind Extract and Zinc (II) against Micrococcus luteus under Planktonic and Biofilm Conditions

Infectious diseases caused by microbial biofilms are a major clinical problem, and new antimicrobial agents that can inhibit biofilm formation and eradicate pre-formed biofilms are urgently needed. Pomegranate extracts are a well-established folkloric medicine and have been used in the treatment of infectious diseases since ancient times, whilst the addition of metal ions, including zinc (II), has enhanced the antimicrobial activity of pomegranate. Micrococcus luteus is generally a non-pathogenic skin commensal bacterium, although it can act as an opportunistic pathogen and cause serious infections, particularly involving catheterization and comorbidities. The aims of this study were to evaluate the holistic activity of pomegranate rind extract (PRE), Zn (II), and PRE/Zn (II) individually and in combination against M. luteus under both planktonic and biofilm conditions. Antimicrobial activity was detected in vitro using the broth dilution method, and synergistic activity was determined using checkerboard and time-kill assays. Effects on biofilm formation and eradication were determined by crystal violet and BacLight^TM Live/Dead staining. PRE and Zn (II) exerted antimicrobial activity against M. luteus under both planktonic and biofilm conditions. After 4 h, potent synergistic bactericidal activity was also found when PRE and Zn (II) were co-administered under planktonic conditions (log reductions: PRE 1.83 ± 0.24, Zn (II) 3.4 ± 0.08, and PRE/Zn (II) 6.88 ± 1.02; p < 0.0001). In addition, greater heterogeneity was induced in the structure of M. luteus biofilm using the PRE/Zn (II) combination compared to when PRE and Zn (II) were applied individually. The activity of PRE and the PRE/Zn (II) combination could offer a novel antimicrobial therapy for the treatment of disease-associated infections caused by M. luteus and potentially other bacteria.

Every breath you take: Impacts of environmental dust exposure on intestinal barrier function-from the gut-lung axis to COVID-19

As countries continue to industrialize, major cities experience diminished air quality, whereas rural populations also experience poor air quality from sources such as agricultural operations. These exposures to environmental pollution from both rural and populated/industrialized sources have adverse effects on human health. Although respiratory diseases (e.g., asthma and chronic obstructive pulmonary disease) are the most commonly reported following long-term exposure to particulate matter and hazardous chemicals, gastrointestinal complications have also been associated with the increased risk of lung disease from inhalation of polluted air. The interconnectedness of these organ systems has offered valuable insights into the roles of the immune system and the micro/mycobiota as mediators of communication between the lung and the gut during disease states. A topical example of this relationship is provided by reports of multiple gastrointestinal symptoms in patients with coronavirus disease 2019 (COVID-19), whereas the rapid transmission and increased risk of COVID-19 has been linked to poor air quality and high levels of particulate matter. In this review, we focus on the mechanistic effects of environmental pollution on disease progression with special emphasis on the gut-lung axis.

Bioburden in sleeping environments from Portuguese dwellings

A wider characterization of indoor air quality during sleep is still lacking in the literature. This study intends to assess bioburden before and after sleeping periods in Portuguese dwellings through active methods (air sampling) coupled with passive methods, such as electrostatic dust cloths (EDC); and investigate associations between before and after sleeping and bioburden. In addition, and driven by the lack of information regarding fungi azole-resistance in Portuguese dwellings, a screening with supplemented media was also performed. The most prevalent genera of airborne bacteria identified in the indoor air of the bedrooms were Micrococcus (41%), Staphylococcus (15%) and Neisseria (9%). The major indoor bacterial species isolated in all ten studied bedrooms were Micrococcus luteus (30%), Staphylococcus aureus (13%) and Micrococcus varians (11%). Our results highlight that our bodies are the source of the majority of the bacteria found in the indoor air of our homes. Regarding air fungal contamination, Chrysosporium spp. presented the highest prevalence both in after the sleeping period (40.8%) and before the sleeping period (28.8%) followed by Penicillium spp. (23.47% morning; 23.6% night) and Chrysonilia spp. (12.4% morning; 20.3% night). Several Aspergillus sections were identified in air and EDC samples. However, none of the fungal species/strains (Aspergillus sections Fumigati, Flavi, Nidulantes and Circumdati) were amplified by qPCR in the analyzed EDC. The correlations observed suggest reduced susceptibility to antifungal drugs of some fungal species found in sleeping environments. Toxigenic fungal species and indicators of harmful fungal contamination were observed in sleeping environments.

Long-term experience with implantable infusion pumps for intravenous treprostinil in pulmonary arterial hypertension-procedural safety and system-related complications

Implantable pumps for intravenous treprostinil provide a promising option to overcome drawbacks of parenteral prostanoid administration with external pumps in pulmonary hypertension. We retrospectively analyzed 85 patients undergoing implantation in a single center since 2010. In our cohort, serious complications were rare, and flow rate increase over time warrants careful monitoring.

Pulmonary Arterial Hypertension: A Palliative Medicine Review of the Disease, Its Therapies, and Drug Interactions

Pulmonary arterial hypertension (PAH) is often a progressive and ultimately fatal disease. It is characterized by an elevated mean pulmonary arterial pressure because of disease of the small pulmonary arterioles. PAH leads to a constellation of symptoms, including dyspnea, fatigue, syncope, chest discomfort, and peripheral edema. Disease-targeted therapies for PAH produce symptomatic and functional improvement, but long-term survival remains uncommon without lung transplantation. Palliative care is appropriate to support patients with advanced PAH who typically have a high symptom burden. However, palliative care has historically focused on supporting patients with malignant disease, rather than progressive chronic disease such as PAH. Our aim is to provide palliative care clinicians with a background in the classification, pathophysiology, and modern treatment of PAH. This review describes disease-targeted therapies and their effects on symptoms, physical functioning, and health-related quality of life. We also review the unique physiology of PAH and its implication for palliative interventions. Pharmacological interactions with, and precautions related to commonly used palliative care medications, are discussed.

Sildenafil for Pulmonary Arterial Hypertension

Pulmonary hypertension is a life-threatening illness with debilitating physical and emotional consequences. The progression of this devastating disease is characterized by a continuous increase in pulmonary vascular resistance, which results in elevated pulmonary artery pressure and leads to right heart failure. Treatment is focused on targeting the underlying complex etiology via the endothelin, prostacyclin, and nitric oxide (NO) pathways. Emergence of new treatments over the past 2 decades has led to improvement in the functional status and time to clinical worsening. Even with recent advances, outcomes remain suboptimal. Phosphodiesterase-5 (PDE-5) inhibitors, such as sildenafil, were approved for treatment of pulmonary arterial hypertension (PAH) by the Food and Drug Administration (FDA) in 2005, which holds promise in improving quality of life and therefore making this class of medications effective palliative therapy agents. In this review, we summarize the emergence of sildenafil as a treatment for PAH and its role as palliative therapy.

lloprost delivered via the BREELIBTM nebulizer: a review of the clinical evidence for efficacy and safety

Inhaled iloprost is a well-established medication to treat pulmonary arterial hypertension (PAH), a serious and potentially fatal disease of the pulmonary resistance vessels. The therapeutic administration of iloprost requires six to nine inhalations per day, due to the short biological half-life of this prostacyclin analogue. The I-Neb^TM AAD^TM, introduced in 2006, is the most commonly used nebulizer for delivering iloprost, requiring at least 6.5 min for an inhaled dose of 5 µg. In order to reduce inhalation time, a portable nebulizer based on modern-device technology was developed. The acute safety and tolerability of rapid iloprost inhalation via the BREELIB^TM nebulizer was assessed in a four-part clinical trial. In this review, I describe the rationale and features of the new nebulizer, with particular emphasis on the safety and tolerability profile of iloprost inhalation via BREELIB^TM observed in the first clinical studies. Meanwhile, the BREELIB^TM nebulizer is approved and available for inhaled iloprost therapy combining significantly reduced inhalation time with good tolerability. This new approach will certainly improve patient convenience and compliance, possibly resulting in broader acceptance and improved efficacy of iloprost aerosol therapy in PAH.

Pulmonary Arterial Hypertension Emergency Complications and Evaluation: Practical Guide for the Advanced Practice Registered Nurses in the Emergency Department

Pulmonary hypertension (PH) complicates common diseases and can lead to worsening symptoms and increased mortality. A specific group of PH, pulmonary arterial hypertension (PAH), World Health Organization Group 1, may present to the emergency department (ED). We review common ED presentations of patients with PAH such as cardiac arrest/sudden death, right ventricular failure, syncope, hypoxemic respiratory failure, arrhythmias, hemoptysis, pulmonary embolism, chest pain/left main compression syndrome, infection, and considerations for PAH medication administration. We include a case study to illustrate a real example with a positive outcome, and an algorithm for evaluating and triaging patients with PAH in the ED. The ability to recognize, triage, and communicate changes in PAH disease status in a multidisciplinary team approach between the patient, family, specialty pharmacy, and specialized health care providers such as the PH team, is essential for ED providers who are evaluating and treating patients with PAH.

Treatment of pulmonary arterial hypertension: A review of drugs available for advanced therapy

Pulmonary hypertension (PH) has traditionally been considered a rare disease with a uniformly poor prognosis. However, this was prior to the introduction of advanced therapies for this condition, and more recent registries in the treatment era have shown 5-year survival rates of up to 65%. Prior to 2000, there was only one licensed therapy for pulmonary arterial hypertension (PAH); less than 20 years later, the US Food and Drug Administration has approved 14 different medications for PAH. This review aims to summarise for the general pulmonologist the evidence for the current internationally available advanced therapies for PAH (World Health Organization Group I disease), which is characterised haemodynamically by the presence of precapillary PH in the absence of another cause. The benefit of these agents, either alone or in combinations, is now undisputed and their use is advocated in all current international guidelines for PAH. The improvement in survival of patients with PAH over the concurrent timeline emphasises the importance both of the availability and usage of effective therapies and of patients being seen in specialist centres, where physicians are familiar with using these therapies.

Inhalation of repurposed drugs to treat pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a rare, but severe and life-threatening disease characterized by vasoconstriction and remodeling of the pulmonary arterioles, leading to progressive increase in pulmonary vascular resistance and ultimately to right-heart failure. In the last two decades, significant progress in treatment of PAH has been made, with currently 12 drugs approved for targeted therapy. Among these, the stable prostacyclin analogues iloprost and treprostinil have been repurposed for inhalation. The paper highlights the development of the two drugs emphasizing the rationale and advantages of the inhalative approach. Despite substantial advances in the specific, mainly vasodilatory PAH therapy, disease progression is mostly inevitable and mortality remains unacceptably high. Thus, introduction of new drugs targeting the cancer-like remodeling of the diseased pulmonary arteries is urgently needed. Inhalation offers pulmonary selectivity and will hopefully pioneer the repurposing of novel highly potent drugs for effective aerosol therapy of PAH.

Intravenous treprostinil via an implantable pump in pediatric pulmonary arterial hypertension

Intravenous prostacyclin-based therapy improves survival in children with pulmonary arterial hypertension (PAH), but is typically administered via an external infusion pump, which places a considerable burden on the patient. Implanted pumps may overcome some of the limitations of external pumps. We describe the first long-term use of an implanted pump for intravenous treprostinil delivery in a pediatric patient with PAH. Our patient was experiencing marked dyspnea on exertion despite triple combination therapy with bosentan, sildenafil, and inhaled iloprost. Parenteral prostacyclin-based therapy was discussed and the patient rejected options involving external pumps; she finally chose intravenous treprostinil delivery via an implanted pump (LENUS Pro®; fixed flow rate; 20 ml reservoir). The patient underwent pump implantation in July 2012 (aged 14 years) under general anesthesia with no peri- or postoperative complications. She showed marked improvements in fatigue and dyspnea over the subsequent weeks, and her inhaled iloprost regimen was slowly decreased and stopped after six months. During follow-up, the pump showed an unexpected, progressive increase in flow rate that allowed a treprostinil dose of 170 ng/kg/min to be achieved, but at the cost of shortened intervals between refills. The pump was therefore replaced in August 2017 with a newer model with an adjustable flow rate (Siromedes®). A catheter dislocation was corrected under local anesthesia one week after the replacement surgery. The patient is currently receiving treprostinil 170 ng/kg/min with percutaneous refills every 12–13 days. Thus, implantable pumps might be a valuable alternative to external pumps for treprostinil infusion in pediatric PAH.

[Tunnelled central venous catheter infection during treatment with epoprostenol]

INTRODUCTION

Pulmonary arterial hypertension is a pulmonary vascular disease with a poor prognosis. Continuous intravenous treatment with prostacyclin analogues requires the placement of a tunnelled catheter. The occurrence of catheter-related infections in this context is unusual due to the alkaline pH of the prostacyclin analogue solutions.

OBSERVATION

A 50-year-old patient with inherited pulmonary artery hypertension, treated with bosentan, sildenafil and epoprostenol, experienced generalized malaise associated with a weight loss of 9kg over a 12-month period without evidence of a source of infection or malignancy. There was no evidence of hemodynamic disturbance. The diagnosis was made after 1 year of follow-up, when the patient presented with a 38° fever and a biological inflammatory syndrome. Repeated peripheral blood cultures were positive for Dietzia, an alkalophilic coryneform bacillus. The patient's condition responded favourably to antibiotic therapy.

CONCLUSION

Infection of a tunneled intravenous catheter should be considered in the case of non-specific symptoms or where there is evidence of sepsis, in patients treated with intravenous prostacyclin analogues administered intravenously. In this context, the laboratory should be warned to search for slow-growing organisms.

Central line replacement following infection does not improve reinfection rates in pediatric pulmonary hypertension patients receiving intravenous prostanoid therapy

Treatment of pediatric pulmonary hypertension (PH) with IV prostanoids has greatly improved outcomes but requires a central line, posing inherent infection risk. This study examines the types of infections, infection rates, and importantly the effect of line management strategies on reinfection in children receiving IV prostanoids for PH. This study is a retrospective review of all pediatric PH patients receiving intravenous epoprostenol (EPO) or treprostinil (TRE) at one academic tertiary care center between 2000 and 2014. No patients declined participation in the study or were otherwise excluded. Infectious complications were characterized by organism(s), infection rates, time to next infection, and line management decisions (salvage vs. replace). Of the 40 patients followed, 13 sustained 38 infections involving 49 pathogens, with a predominance of gram-positive (GP) organisms (n = 35). The pooled infection rate was 1.06 per 1000 prostanoid days with no difference between EPO and TRE. No significant difference in reinfection rate was observed when comparing line salvage to replacement, regardless of organism type. Both overall and organism-type comparisons suggest longer time between line infections following line salvage compared with line replacement (732 vs. 410 days overall; 793 vs. 363 days for GP; 611 vs. 581 days for gram-negative [GN]; P > 0.05 for all comparisons). Central line replacement following blood stream infections in pediatric PH patients does not improve subsequent infection rates or time to next infection, and may lead to unnecessary risks associated with line replacement, including potential loss of vascular access. A revised approach to central line infections in pediatric PH is proposed.

Totally Implantable IV Treprostinil Therapy in Pulmonary Hypertension Assessment of the Implantation Procedure

BACKGROUND

Prostacyclins improve symptoms and survival in pulmonary arterial hypertension (PAH). In response to risks associated with external delivery systems, an implantable IV infusion system was developed. A multicenter, prospective, single-arm, clinical trial (DelIVery for PAH) was conducted to evaluate this system for treprostinil in PAH. This analysis describes the findings related to the implant procedure.

METHODS

Patients (N = 64) with PAH (World Health Organization group 1) receiving stable IV treprostinil were enrolled. Patients were transitioned to a temporary peripheral IV infusion catheter prior to the procedure. System implantation was performed at 10 centers under general anesthesia or deep IV sedation by clinicians from various specialties. Central venous access was via the cephalic, subclavian, jugular, or axillary vein. Using an introducer and fluoroscopic guidance, the distal tip of the infusion catheter was placed at the superior caval-atrial junction. The catheter was tunneled from the venous access site to an abdominal subcutaneous pocket, where the pump was placed.

RESULTS

Of the 64 patients enrolled, four exited prior to implantation. All 60 implant procedures were successful. At baseline, all patients were receiving treprostinil via an external pump at a mean dose of 71.4 ± 27.8 ng/kg/min (range: 22-142 ng/kg/min). The implant averaged 102 ± 32 min (range: 47-184 min). Clinically significant implant procedure-related complications included one pneumothorax, two infections, and one episode of atrial fibrillation. There were three postimplantation catheter dislocations in two patients. Common implant-related events that were not complications included implant site pain (83%) and bruising (17%).

CONCLUSIONS

The procedure for inserting a fully implantable system for treprostinil was successfully performed, with few complications.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01321073; URL: www.clinicaltrials.gov.

Nanoparticle-Mediated Drug Delivery System for Pulmonary Arterial Hypertension

Nanoparticles have been used as a novel drug delivery system. Drug-incorporated nanoparticles for local delivery might optimize the efficacy and minimize the side effects of drugs. The efficacy and safety of intratracheal administration of prostacyclin analog (beraprost) -incorporated nanoparticles and imatinib (a PDGF-receptor tyrosine kinase inhibitor) -incorporated nanoparticles in Sugen-hypoxia-normoxia or monocrotaline rat models of pulmonary arterial hypertension (PAH) and in human PAH-pulmonary arterial smooth muscle cells have been reported. The use of inhaled drug-incorporated nanoparticles might be a novel approach for the treatment of PAH.

Intravenous treprostinil infusion via a fully implantable pump for pulmonary arterial hypertension

OBJECTIVES

Parenteral prostanoids infused via external pumps are well-established pulmonary arterial hypertension (PAH) treatments. However, local side-effects and systemic infections restrict their use. The purpose of this study was to investigate the safety of a fully implantable treprostinil infusion pump (LENUS Pro^®) in patients with PAH.

METHODS

Thirty patients with PAH undergoing pump implantation (with stable PAH therapy for ≥3 weeks pre-implantation) were included in this prospective, multicenter, observational study (NCT01979822). Primary endpoints were predefined adverse events (AEs) during implantation, in-hospital and/or during 6-month follow-up. Refill-related AEs were a secondary endpoint.

RESULTS

Twenty-nine patients completed 6-month follow-up (one underwent lung transplantation). During implantation, one pneumothorax (not requiring drainage) occurred. Four patients had an in-hospital AE (including one catheter revision). During 6-month follow-up, AEs were most frequent at the first refill (10); the most common AE was seroma around the pump. No infections occurred. One pump required replacement because of a defective septum caused by use of a non-approved refill needle (associated with extravasation). Apart from the extravasation, no refill-related AEs were recorded. Post hoc efficacy analyses showed significant improvements in functional class [number in functional class I/II/III/IV: 0/5/21/2 (baseline) versus 3/8/17/0 (6 months); p = 0.012] and 6-min walk distance (mean ± standard deviation: 407 ± 122 m versus 445 ± 127 m; n = 17; p = 0.014).

CONCLUSIONS

This study supports use of a fully implantable treprostinil infusion pump in patients with PAH requiring parenteral prostanoids. Refills should be performed by specialized healthcare professionals at patients' homes or at experienced centers using approved equipment.

Subcutaneous treprostinil was effective and tolerable in a patient with severe pulmonary hypertension associated with chronic kidney disease on hemodialysis

BACKGROUND

Pulmonary hypertension (PH) is a life-threatening complication in patients with chronic kidney disease on hemodialysis (CKD-HD).

OBJECTIVES

To determine whether subcutaneous infusion of treprostinil was effective and tolerable CKD-PH.

METHODS AND RESULTS

A 57-year-old man was admitted to our hospital due to presyncope and dyspnea during exercise with a history of CKD-HD. Cardiac catheterization revealed high pulmonary arterial pressure (PAP) of 53/24/32 mmHg and pulmonary vascular resistance (PVR) of 11.2 w.u. Upfront combination therapy with bosentan and sildenafil was started. However, 6-month therapy did not attenuate his symptoms, probably due to the high PAP and PVR (60/19/30 mmHg and 5.9 w.u.). We added subcutaneous treprostinil. Surprisingly, 9-month treprostinil (50 ng/kg/min) normalized hemodynamics (PAP: 25/4/13 mmHg and PVR: 1.9 w.u.). His symptoms during excise disappeared without any adverse effects.

CONCLUSION

This is the first report that subcutaneous treprostinil was very effective and tolerable in a PH patient with CKD-HD.

An advanced protocol-driven transition from parenteral prostanoids to inhaled trepostinil in pulmonary arterial hypertension

Patients with pulmonary arterial hypertension (PAH) often require parenteral prostanoids to improve symptoms and signs of PAH. Complications of parenteral prostanoids-such as catheter-related infections and intolerable adverse effects-may develop, prompting transition to inhaled prostanoids. We report a prospective, protocol-driven transition from parenteral prostanoids to inhaled prostanoids with monitoring of exercise gas exchange and acute hemodynamics. Three PAH centers recruited patients transitioning from parenteral prostanoids to inhaled trepostinil. Rigid inclusion criteria were used, including parenteral prostanoid dose < 30 ng/kg/min, New York Heart Association functional class (FC) < 3, and pulmonary vascular resistance (PVR) < 6 Wood units. Of the 9 patients meeting initial inclusion criteria, 3 were excluded. In the remaining patients, the parenteral prostanoid was reduced and the inhaled prostanoid was increased over 24-36 hours with continuous hemodynamic monitoring. Exercise capacity and FC were measured at baseline and weeks 1, 4, and 12. All patients were successfully weaned from parenteral prostanoids. An acute PVR decrease was seen with most inhaled prostanoid doses, but PVR varied throughout the transition. Patients tolerated inhaled prostanoids for 9-12 breaths 4 times a day with no treatment-limiting adverse events. At week 12, FC was unchanged, and all patients continued to receive inhaled prostanoids without serious adverse events or additional PAH therapy. In 5 of 6 patients, 6-minute walk distance and peak [Formula: see text] were within 10% of baseline. Using a strict transition protocol and rigid patient selection criteria, the parenteral prostanoid to inhaled prostanoid transition appeared safe and well tolerated and did not result in clinical deterioration over 12 weeks. Hemodynamic variability noted acutely during transition in our study did not adversely affect successful transition. (Trial registration: ClinicalTrials.gov identifier: NCT01268553).

Treprostinil Administered to Treat Pulmonary Arterial Hypertension Using a Fully Implantable Programmable Intravascular Delivery System: Results of the DelIVery for PAH Trial

BACKGROUND

The use of systemic prostanoids in severe pulmonary arterial hypertension (PAH) is often limited by patient/physician dissatisfaction with the delivery methods. Complications associated with external pump-delivered continuous therapy include IV catheter-related bloodstream infections and subcutaneous infusion site pain. We therefore investigated a fully implantable intravascular delivery system for treprostinil infusion.

METHODS

A multicenter, prospective, single-arm, clinical trial (DelIVery for Pulmonary Arterial Hypertension) was conducted by using an implantable intravascular delivery system. The implanted pumps were refilled percutaneously at least every 12 weeks. The primary end point was the rate of catheter-related complications using the new model 10642 catheter compared with a predefined objective performance criterion of 2.5 per 1,000 patient-days based on the literature.

RESULTS

Patients (n = 60) with severe PAH (World Health Organization group 1) receiving a stable dose of IV treprostinil for at least 4 weeks received an implant device and were followed up for 12.1 ± 4.4 months. Six catheter-related complications occurred, corresponding to a complication rate of 0.27 per 1,000 patient-days. The 97.5% upper one-sided confidence bound of 0.59 was less than the predefined criterion of 2.5 per 1,000 patient-days (P < .0001). Plasma treprostinil levels at 1 week postimplantation were highly correlated with baseline levels (r = 0.91; P < .0001). The delivery system management time as reported by the patients was 2.5 ± 1.7 hours per week preimplantation, and this time decreased to 0.6 ± 0.8 hour per week at 6 months' postimplantation (P < .0001). All patients rated overall satisfaction with the implantable system as good, very good, or excellent at 6 weeks and 6 months. There were no catheter-related bloodstream infections or catheter occlusions.

CONCLUSIONS

The implantable intravascular delivery system delivered treprostinil to patients with PAH with a low rate of catheter-related complications and a high rate of patient satisfaction.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01321073; URL: www.clinicaltrials.gov.

Challenges in pulmonary hypertension: managing the unexpected

The diverse challenges associated with diagnosis and management of patients with pulmonary hypertension are illustrated in this case-based review. Case 1 describes a patient diagnosed with pulmonary arterial hypertension (PAH) with right heart failure and active systemic lupus erythematosus who was effectively treated with an up-front triple combination of PAH therapies and immunosuppressive therapy. In case 2, a diagnosis of pulmonary veno-occlusive disease was reached after a combined approach of clinical suspicion, physical examination, and invasive and noninvasive tests. Cautious PAH therapy and high-dose diuretics provided clinical benefit in this patient and served as a bridge to lung transplantation. These cases highlight the need for ongoing follow-up of patients with PAH, comprising frequent assessment of treatment success and continued diagnostic evaluation.

Central venous line complications with chronic ambulatory infusion of prostacyclin analogues in pediatric patients with pulmonary arterial hypertension

Chronic infusion of prostacyclin (PGI2) via a Broviac central venous line (CVL) is attended by risk of CVL-related complications, but we know of only one report regarding CVL-associated bloodstream infection (BSI) with PGI2 in children and none regarding other complications. We conducted a retrospective cohort study involving pediatric patients with pulmonary hypertension treated with chronic intravenous infusion of PGI2 at Boston Children's Hospital and determined the rate (per 1,000 line-days) of various CVL-related complications. We also determined how often complications necessitated line replacement and hospitalization, time to replacement of CVLs, and interpatient variability in the incidence of complications. From 1999 until 2014, 26 patients meeting follow-up criteria had PGI2 infusion, representing 43,855 line-days; mean follow-up was 56 months (range, 1.4-161 months). The CVL complication rates (per 1,000 line-days) were as follows: CVL-BSI, 0.25; superficial line infection, 0.48; impaired integrity, 0.59; occlusion, 0.09; and malposition, 0.32. The total complication rate was 1.73 cases per 1,000 line-days. All CVL-BSI and malposition cases were treated with CVL removal and replacement. Of CVLs with impaired integrity, 23 could be repaired and 3 required replacement. Six of 21 superficial CVL infections required replacement of the CVL. Three of 4 occluded CVLs were replaced. CVL complications occasioned 65 hospitalizations. There was marked interpatient variability in the rate of complications, much but not all of which appeared to be related to duration of CVL placement. We conclude that non-BSI complications are very significant and that efforts to teach and emphasize other aspects of line care are therefore very important.

Bloodstream Infections in Patients Given Treatment With Intravenous Prostanoids

Objective.

In September 2006, the Centers for Disease Control and Prevention was notified of cases of gram-negative bloodstream infection (BSI) occurring among outpatients who received an intravenous formulation of the prostanoid treprostinil. An investigation was conducted to determine rates of prostanoid-associated BSI in this patient population and possible risk factors for infection.

Methods.

We performed a retrospective cohort study of patients who had received intravenous formulations of at least 1 of the 2 approved prostanoids (epoprostenol and treprostinil) from January 1, 2004, through late 2006. Chart reviews were conducted at 2 large centers for pulmonary arterial hypertension, and a survey of infection control practices was conducted at 1 center.

Results.

A total of 224 patients were given intravenous prostanoid treatment, corresponding to 146,093 treatment-days during the study period. Overall, there were 0.55 cases of BSI and 0.18 cases of BSI due to gram-negative organisms per 1,000 treatment-days. BSI rates were higher for patients who received intravenous treprostinil than for patients who received intravenous epoprostenol (1.13 vs. 0.42 BSIs per 1,000 treatment-days; P < .001), as were rates of BSI due to gram-negative organisms (0.81 vs. 0.04 BSIs per 1,000 treatment-days; P < .001). Adjusted hazard ratios for all BSIs and for BSIs due to gram-negative organisms were higher among patients given treatment with intravenous treprostinil. The survey identified no significant differences in medication-related infection control practices.

Conclusion.

At 2 centers, BSI due to gram-negative pathogens was more common than previously reported and was more frequent among patients given treatment with intravenous treprostinil than among patients given treatment with intravenous epoprostenol. Whether similar results would be found at other centers for pulmonary arterial hypertension warrants further investigation. This investigation underscores the importance of surveillance and evaluation of healthcare-related adverse events in patients given treatment primarily as outpatients.

Pharmacologic therapy for pulmonary arterial hypertension in adults: CHEST guideline and expert panel report

OBJECTIVE

Choices of pharmacologic therapies for pulmonary arterial hypertension (PAH) are ideally guided by high-level evidence. The objective of this guideline is to provide clinicians advice regarding pharmacologic therapy for adult patients with PAH as informed by available evidence.

METHODS

This guideline was based on systematic reviews of English language evidence published between 1990 and November 2013, identified using the MEDLINE and Cochrane Library databases. The strength of available evidence was graded using the Grades of Recommendations, Assessment, Development, and Evaluation methodology. Guideline recommendations, or consensus statements when available evidence was insufficient to support recommendations, were developed using a modified Delphi technique to achieve consensus.

RESULTS

Available evidence is limited in its ability to support high-level recommendations. Therefore, we drafted consensus statements to address many clinical questions regarding pharmacotherapy for patients with PAH. A total of 79 recommendations or consensus statements were adopted and graded.

CONCLUSIONS

Clinical decisions regarding pharmacotherapy for PAH should be guided by high-level recommendations when sufficient evidence is available. Absent higher level evidence, consensus statements based upon available information must be used. Further studies are needed to address the gaps in available knowledge regarding optimal pharmacotherapy for PAH.

Transition from intravenous or subcutaneous prostacyclin therapy to inhaled treprostinil in patients with pulmonary arterial hypertension: a retrospective case series

WHAT IS KNOWN AND OBJECTIVE

Inhaled treprostinil represents an attractive alternative to the other available prostacyclin formulations by obviating the use of continuous infusions and its associated risks. Published evidence describing the process of transition from infusion prostacyclin therapy to inhaled treprostinil is limited. The purpose of this report is to describe an inpatient protocol for transitioning patients with pulmonary arterial hypertension (PAH) from intravenous (IV) or subcutaneous (SQ) prostacyclin therapy to inhaled treprostinil.

METHODS

A retrospective case cohort study was performed evaluating medical records of three patients undergoing transition from IV/SQ continuous infusion prostacyclin therapy to inhaled treprostinil. The transition protocol and clinical data were collected prospectively.

RESULTS AND DISCUSSION

Haemodynamics, six-min walk distance (6MWD), World Health Organization (WHO) functional class, modified Borg Dyspnea Score and brain natriuretic peptide prior to and after transition remained similar. All patients were receiving concomitant oral PAH medications prior to and after conversion. Adverse effects during the change were mild. No patients discontinued inhaled treprostinil following transition. At long-term follow-up, functional class remained stable at WHO functional class II or better. Patient 1 and Patient 3 demonstrated stable to modest improvement in 6MWD, whereas Patient 2 had a slight decrease in 6MWD. The transition to inhaled treprostinil from IV/SQ infusion prostacyclin therapy appears to be safe in carefully selected patients.

WHAT IS NEW AND CONCLUSION

Our report describes a standard method used to transition patients from IV/SQ infusion prostacyclin to inhaled treprostinil.

Two formulations of epoprostenol sodium in the treatment of pulmonary arterial hypertension: EPITOME-1 (epoprostenol for injection in pulmonary arterial hypertension), a phase IV, open-label, randomized study

BACKGROUND

Epoprostenol sodium with arginine-mannitol excipients (epoprostenol AM; Veletri [Actelion Pharmaceuticals Ltd, Allschwil, Switzerland]) and epoprostenol sodium with glycine-mannitol excipients (epoprostenol GM; Flolan [GlaxoSmithKline, Triangle Park, NC]) are intravenous treatments for pulmonary arterial hypertension (PAH). Epoprostenol AM contains different inactive excipients, resulting in greater stability at room temperature compared with epoprostenol GM.

METHODS

In this prospective, multicenter, open-label, randomized, phase IV exploratory study, epoprostenol-naïve patients in need of injectable prostanoid therapy were randomized 2:1 to open-label epoprostenol AM or epoprostenol GM. The study period was 28 days, followed by a 30-day safety follow-up. Study aims were to descriptively compare the safety, tolerability, drug metabolite levels, and treatment effects of epoprostenol AM and epoprostenol GM in PAH. Statistical analysis was descriptive only because of the exploratory nature of the study.

RESULTS

Thirty patients with PAH (18-70 years, 24 women, 20 idiopathic PAH) were randomized to epoprostenol AM (n = 20) or epoprostenol GM (n = 10). Most frequently reported adverse events included jaw pain, headache, nausea, and flushing. Two deaths occurred during the study period, and 1 death occurred during the 30-day safety follow-up period, all in patients receiving epoprostenol AM. All deaths were classified by the treating physician as unrelated to epoprostenol AM. The median (range) change from baseline to day 28 in 6-minute walk distance was 36 m (-127 to 210 m) and 49 m (-44 to 110 m) for the epoprostenol AM and epoprostenol GM groups, respectively.

CONCLUSIONS

In this randomized clinical study of epoprostenol AM in PAH, use of this novel preparation with greater room temperature stability was well tolerated.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry: a fundamental shift in the routine practice of clinical microbiology

Within the past decade, clinical microbiology laboratories experienced revolutionary changes in the way in which microorganisms are identified, moving away from slow, traditional microbial identification algorithms toward rapid molecular methods and mass spectrometry (MS). Historically, MS was clinically utilized as a high-complexity method adapted for protein-centered analysis of samples in chemistry and hematology laboratories. Today, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS is adapted for use in microbiology laboratories, where it serves as a paradigm-shifting, rapid, and robust method for accurate microbial identification. Multiple instrument platforms, marketed by well-established manufacturers, are beginning to displace automated phenotypic identification instruments and in some cases genetic sequence-based identification practices. This review summarizes the current position of MALDI-TOF MS in clinical research and in diagnostic clinical microbiology laboratories and serves as a primer to examine the "nuts and bolts" of MALDI-TOF MS, highlighting research associated with sample preparation, spectral analysis, and accuracy. Currently available MALDI-TOF MS hardware and software platforms that support the use of MALDI-TOF with direct and precultured specimens and integration of the technology into the laboratory workflow are also discussed. Finally, this review closes with a prospective view of the future of MALDI-TOF MS in the clinical microbiology laboratory to accelerate diagnosis and microbial identification to improve patient care.

From short-term benefits to long-term outcomes: the evolution of clinical trials in pulmonary arterial hypertension

Abstract Over the past 2 decades, major advances in our understanding of pulmonary arterial hypertension (PAH) have led to the development of new targeted therapeutics and management strategies that have provided benefits to patients with this devastating disease. Despite such improvements, no therapies are curative, and PAH remains a progressive disease associated with high morbidity and suboptimal survival in many patients. Clinical research in PAH is currently at a crossroads. To move forward, not only are new therapies needed, but novel approaches to clinical trial design are also required. Trials should be designed to assess the longer-term benefits of investigational therapies in what has become a chronic disease. Moreover, there is a need to consider moving away from short-term trials that use markers such as the 6-minute walk distance as a measure of exercise capacity as primary end points to longer-term, event-driven trials with composite end points made up of clinically relevant measures that better reflect the ultimate goals of reducing morbidity and mortality. A shift in trial design may also be useful in overcoming some of the muted results from recent pivotal phase III studies of combination therapy by allowing the potential of these regimens to be more comprehensively assessed.

An evaluation of the pharmacokinetics of treprostinil diolamine in subjects with hepatic impairment

WHAT IS KNOWN AND OBJECTIVE

Treprostinil diolamine (oral treprostinil) is a prostacyclin analogue under evaluation for the treatment for pulmonary arterial hypertension (PAH). This study assessed the pharmacokinetics (PK) and safety of treprostinil following oral administration of a single sustained-release 1 mg dose in subjects with hepatic impairment.

METHODS

Four cohorts, including healthy volunteers, and subjects with mild, moderate and severe hepatic impairment were enrolled. Thirty subjects completed the study. Mean treprostinil clearance values (CL/F) decreased with the severity of hepatic impairment. The decrease in CL/F resulted in a marked increase in exposure levels of treprostinil. Relative to healthy subjects, mean area under the curve from time zero to 24 h after dosing interval (AUC0-24) values in subjects with mild, moderate and severe hepatic impairment increased by approximately 2·2-, 4·9- and 7·6-fold, respectively. The most frequent adverse events (AEs) exhibited in this study were similar to those seen with prostacyclin and its analogues and with AEs seen in other clinical studies with oral treprostinil (e.g. headache, diarrhoea and nausea). The overall incidence of all AEs and the specific events of headache and nausea increased with severity of hepatic impairment.

WHAT IS NEW AND CONCLUSION

Based on these results, dosage adjustments should be performed in subjects with hepatic impairment.

Opportunistic bacteria in dental unit waterlines: assessment and characteristics

AIM

The study aimed to determine qualitative and quantitative contamination of dental unit reservoir water with aerobic and facultative anaerobic bacteria, with regards to health risk to dental staff and patients.

MATERIALS & METHODS

The study material included water samples from 107 unit reservoirs. Conventional microbiological methods were used. The isolated bacteria were divided into three groups according to pathogenic mechanisms.

RESULTS

Dental unit water contamination was widespread. The isolated bacteria average concentration was 1.1 × 10(5) CFU/ml, with Ralstonia pickettii as the prevailing species (49.33%). The total potentially pathogenic bacteria were 54.54% of all the isolated bacteria. Bacteria causing infectious and invasive diseases constituted over one-half of this group, while allergizing and immunotoxic bacteria occurred in smaller quantities.

CONCLUSION

The presence of over 50% potentially pathogenic microorganisms among the isolated bacteria and their very high concentrations call for the daily use of effective methods to reduce dental unit water contamination and health risk.

Pulmonary arterial hypertension: classification and therapy with a focus on prostaglandin analogs

Pulmonary arterial hypertension, part of the larger spectrum of disorders causing pulmonary hypertension, is a complex and progressive disease of multiple etiologies that ultimately leads to vascular remodeling, right-sided heart failure, and death. Advances in treatment over the past 15 to 20 years have dramatically reduced the morbidity and mortality of the disease, but often have significant drawbacks. Of the more recently approved therapies, the prostaglandin analogs have been shown to have the greatest therapeutic benefit but are also the most difficult to administer, many being given as continuous intravenous infusions in the ambulatory setting. After a case presentation highlighting some of the challenges that accompany treatment with these agents, this article reviews the diagnosis and classification of pulmonary hypertension and pulmonary arterial hypertension and gives a brief overview of the various other pharmacologic agents used in its treatment. A more comprehensive review of the biochemistry of prostaglandins and the pharmacology and clinical use of this class of drugs follows. Recommended treatment guidelines are also discussed.

Bloodstream infections in patients with pulmonary arterial hypertension treated with intravenous prostanoids: insights from the REVEAL REGISTRY®

OBJECTIVE

To evaluate the rate of and potential risk factors for bloodstream infections (BSIs) using data from the REVEAL (Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension [PAH] Disease Management) REGISTRY(®), which provides current information about patients with PAH.

PATIENTS AND METHODS

Patients were enrolled from March 30, 2006, through December 8, 2009, and data on reported BSIs were collected through the third quarter of 2010. Bloodstream infection rates were calculated per 1000 patient-days of risk.

RESULTS

Of 3518 patients enrolled, 1146 patients received intravenous (IV) prostanoid therapy for more than 1 day (no BSI, n=1023; ≥1 BSI, n=123; total BSI episodes, n=166). Bloodstream infections rates were significantly increased in patients receiving IV treprostinil vs IV epoprostenol (0.36 vs 0.12 per 1000 treatment days; P<.001), primarily due to gram-negative organisms (0.20 vs 0.03 per 1000 treatment days; P<.001). Multivariate analysis adjusting for age, causes of PAH, and year of BSI found that treatment with IV treprostinil was associated with a 3.08-fold increase (95% confidence interval, 2.05-4.62; P<.001) in BSIs of any type and a 6.86-fold increase (95% confidence interval, 3.60-13.07; P<.001) in gram-negative BSIs compared with treatment with IV epoprostenol.

CONCLUSION

Compared with IV epoprostenol therapy, treatment with IV treprostinil is associated with a significantly higher rate of gram-negative BSIs; observed differences in BSI rate did not seem to be due to any other analyzed factors.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00370214.

Assessment of microbial diversity in biofilms recovered from endotracheal tubes using culture dependent and independent approaches

Ventilator-associated pneumonia (VAP) is a common nosocomial infection in mechanically ventilated patients. Biofilm formation is one of the mechanisms through which the endotracheal tube (ET) facilitates bacterial contamination of the lower airways. In the present study, we analyzed the composition of the ET biofilm flora by means of culture dependent and culture independent (16 S rRNA gene clone libraries and pyrosequencing) approaches. Overall, the microbial diversity was high and members of different phylogenetic lineages were detected (Actinobacteria, beta-Proteobacteria, Candida spp., Clostridia, epsilon-Proteobacteria, Firmicutes, Fusobacteria and gamma-Proteobacteria). Culture dependent analysis, based on the use of selective growth media and conventional microbiological tests, resulted in the identification of typical aerobic nosocomial pathogens which are known to play a role in the development of VAP, e.g. Staphylococcus aureus and Pseudomonas aeruginosa. Other opportunistic pathogens were also identified, including Staphylococcus epidermidis and Kocuria varians. In general, there was little correlation between the results obtained by sequencing 16 S rRNA gene clone libraries and by cultivation. Pyrosequencing of PCR amplified 16 S rRNA genes of four selected samples resulted in the identification of a much wider variety of bacteria. The results from the pyrosequencing analysis suggest that these four samples were dominated by members of the normal oral flora such as Prevotella spp., Peptostreptococcus spp. and lactic acid bacteria. A combination of methods is recommended to obtain a complete picture of the microbial diversity of the ET biofilm.