Extrinsic risk factors for pneumonia in the patient at high risk of infection

Effect of laminar air flow and building construction on aspergillosis in acute leukemia patients: a retrospective cohort study

Background

The preventive effect of laminar air flow (LAF) on aspergillosis has been observed in patients with hematological malignancies. However, the short follow-up period limits the interpretation of study results.

Methods

To assess the preventive effect of long-term LAF use on aspergillosis in its long-term use, we retrospectively analyzed 124 acute leukemia patients at our hospital between January 2005 and March 2016. We compared the incidence of aspergillosis before (May 2008) and during the construction of a new building (June 2008–January 2010) and in the early (February 2010–March 2014) and late (April 2014–March 2016) periods after moving to a new hematology ward with an LAF system. The 2008 European Organization for Research and Treatment of Cancer and Mycosis Study Group criteria were used for the diagnosis of aspergillosis.

Results

Fourteen patients were diagnosed with possible, probable, or definite aspergillosis. Cumulative incidence rates of aspergillosis at day 180 were 12.4, 24.9, 9.3, and 25.1% before construction, during construction, in the early period after moving to a new ward, and in the late period after moving to a new ward, respectively (p = 0.106). Multivariate analysis showed that the LAF system tended to reduce the risk of aspergillosis in the early period (before construction vs. early period; hazards ratio (HR) = 1.97, p = 0.463 and during construction vs. early period;HR = 3.42, p = 0.184), but the risk increased in the late period (late vs. early period, HR = 5.65, p = 0.035).

Conclusions

Building construction might increase the risk of aspergillosis. Short-term LAF use might reduce aspergillosis risk, but its long-term use is inadequate, although we could not exclude the possibility of increased risks in the recent period due to continued improvements in the different areas of our hospital. Strict maintenance, more effective LAF system, and optimization of aspergillosis prophylaxis may be necessary.

Incidence of Nosocomial Aspergillosis in Patients with Leukemia Over a Twenty-Year Period

The incidence of invasive nosocomial aspergillosis was studied in leukemia patients at an oncology center from 1964 to 1983. A total of 97 cases of aspergillosis occurred in 1,866 patients, yielding an overall case rate of 5.2 cases per 100 patients and an incidence rate of 9.1 per 10,000 patient days. The highest incidence rate was in patients with chronic myelogenous leukemia (13.7 cases per 10,000 patient days), followed by patients with acute myelogenous leukemia (10.6 cases per 10,000 patient days). Subdividing patients after 1978 into those receiving bone marrow transplantation and those who did not demonstrated the predisposition of transplant recipients to aspergillosis. The rates of aspergillosis among those patients who did not receive a bone marrow transplant were highest for patients with acute myelogenous leukemia. Increases in the annual rates of aspergillosis over time coincided with the level of internal renovation activity and major construction projects upwind of patient care facilities.

Failure of the Sterile Air-Flow Component of a Protected Environment Detected by Demonstration of Chaetomium Species Colonization of Four Consecutive Immunosuppressed Occupants

Four bone marrow transplant recipients consecutively occupying the same room on our Oncology-Hematology Special Care Unit (OHSCU) became colonized with Chaetomium species between January and April, 1987. These patients, aged 27 to 43 years, were immunocompromised as a result of intensive chemotherapy, and were consequently at increased risk for development of invasive fungal infection. At the time of Chaetomium colonization, all patients were febrile, two had transient new infiltrates on chest x-ray, and three were receiving amphotericin B therapy. Subsequent environmental cultures revealed Chaetomium contamination of the OHSCU air-handling system, including the HEPA (high-efficiency particulate air) filters in seven of the nine rooms comprising the unit. Because fungal colonization of HEPA filters used to create a “protective environment” for immunocompromised patients can occur and can serve as a source for patient infections, guidelines concerning proper surveillance of these HEPA filters should be established. We suggest that before a new patient enters a “protected” room, the clean side of the HEPA filter should be cultured. If fungi are recovered from that culture, we would recommend changing the filter.

Our recommendations for avoiding exposure to fungi outside the hospital for patients with haematological cancers

Despite several chemotherapeutic and preventative advances, opportunistic fungal infections remain common unintended consequences of cancer treatment. Currently, cancer patients spend most of their time between treatments at home, where they can inadvertently come across potential hazards from environmental and food sources. Therefore, infection prevention measures are of the utmost importance for these patients. Although clinicians closely observe patients throughout their treatment courses in the hospital, the focus of clinical visits is predominantly on cancer care, and clinicians seldom provide recommendations for prevention of such infections. Herein, we provide practical recommendations for busy clinicians to help them educate patients regarding potential sources of fungal infections outside the hospital.

[Quantitative assessment of fungal risk in the case of construction works in healthcare establishments: Proposed indicators for the determination of the impact of management precautions on the risk of fungal infection]

Construction works in healthcare establishments produce airborne fungal spores and considerably increase the risk of exposure of immunosuppressed patients. It is necessary to reinforce protective measures, or even to implement specific precautions, during this critical phase. The aim of these precautions is to protect both those areas, which are susceptible to dust, and patients at risk of a fungal infection particularly invasive aspergillosis. When construction works are planned in healthcare establishments, the first step consists in the characterisation of the environmental fungal risk and the second one in proposing risk management methods. It is then essential to establish impact indicators in order to evaluate the risk management precautions applied. The working group promoted by the French societies of medical mycology and hospital hygiene (SFMM & SF2H) details here both environmental and epidemiological impact indicators that can be used.

Bacterial Infections

In Osier’s time, bacterial pneumonia was a dreaded event, so important that he borrowed John Bunyan’s characterization of tuberculosis and anointed the pneumococcus, as the prime pathogen, “Captain of the men of death.”1 One hundred years later much has changed, but much remains the same. Pneumonia is now the sixth most common cause of death and the most common lethal infection in the United States. Hospital-acquired pneumonia is now the second most common nosocomial infection.2 It was documented as a complication in 0.6% of patients in a national surveillance study,3 and has been reported in as many as 20% of patients in critical care units.4 Furthermore, it is the leading cause of death among nosocomial infections.5 Leu and colleagues6 were able to associate one third of the mortality in patients with nosocomial pneumonia to the infection itself. The increase in hospital stay, which averaged 7 days, was statistically significant. It has been estimated that nosocomial pneumonia produces costs in excess of $500 million each year in the United States, largely related to the increased length of hospital stay.

Clinical implications of environmental sources for Aspergillus

Invasive aspergillosis presents a formidable problem for both diagnosis and therapy. Therefore, prevention is a very important strategy in controlling this disease. Preventing invasive aspergillosis demands a clear understanding of the environmental sources of Aspergillus spp. and how this mould is transmitted to patients. Insight into the sources of exposure, mechanisms of transmission, and host susceptibility to infection are vital to appropriately direct preventive strategies to those settings where the risk of infection is the highest and consequently the impact of prevention the greatest.

The pathogenesis of fatal outcome in murine pulmonary aspergillosis depends on the neutrophil depletion strategy

Aspergillus fumigatus causes invasive disease in severely immunocompromised hosts but is readily cleared when host innate defenses are intact. Animal models for evaluation of therapeutic strategies to combat invasive aspergillosis that closely mimic human disease are desirable. We determined optimal dosing regimens for neutrophil depletion and evaluated the course of infection following aerosol infection in mice by determining survival, organ fungal burden, and histopathology in mice in which neutropenia was induced by three methods, administration of granulocyte-depleting monoclonal antibody RB6-8C5 (MAb RB6), administration of cyclophosphamide, and administration of both agents. Administration of either individual agent resulted in a requirement for relatively high conidial inocula to achieve 100% mortality in both BALB/c and C57BL/6 mice, although the infection appeared to be somewhat more lethal in C57BL/6 mice. Death following induction of neutropenia with MAb RB6 occurred when a relatively low fungal burden was present in the lung and may have been related to the inflammatory response associated with neutrophil recovery. In contrast, administration of both agents reduced the lethal inoculum in each mouse strain by approximately 1 log(10), and C57BL/6 mice that received both agents had a higher fungal burden and less inflammation in the lung at the time of death than BALB/c mice or mice of either strain that received MAb RB6 alone. Our data suggest that the relationship among fungal burden, inflammation, and death is complex and can be influenced by the immunosuppression regimen, the mouse strain, and the inoculum.

A highly effective method for removing suspended poliovirus from water using a positively-charged carbon felt electrode

We developed an effective system to eliminate poliovirus from modified tap water using a positively-charged carbon felt electrode. The zeta potential of polioviruses was measured using laser microscopic electrophoresis. Poliovirus adsorption to the electrode was examined by indirect immunofluorescence. The tissue culture infective dose (TCID) of poliovirus type 2 (Sabin strain) was determined using human rhabdomyosarcoma cells (RD cells). Poliovirus VP2 gene copy numbers were assessed by reverse transcription followed by a quantitative real-time polymerase chain reaction. The mean zeta potential of the viruses was -20 mV. Relatively large numbers of polioviruses (10(3) or 4 x 10(3) TCID(50)/0.1 ml) could be removed by adsorption to the electrode, drastically decreasing TCID and copy numbers of poliovirus genome in the water. Virus elimination was dependent on electric current and time. Thus, the positively-charged carbon felt electrode effectively adsorbed polioviruses. The system may prove applicable to the elimination of certain viruses from water.

Impact of portable air filtration units on exposure of haematology-oncology patients to airborne Aspergillus fumigatus spores under field conditions

We undertook a one-year study to investigate the impact of the NSA model 7100A/B portable air filtration unit on exposure of haematology-oncology patients to airborne Aspergillus fumigatus spores under field conditions. Weekly measurements for airborne A. fumigatus were conducted in indoor and outdoor air, and surveillance for invasive aspergillosis was based on a combination of ward liaison, targeted chart review and consultation with the medical staff. The mean indoor A. fumigatus counts (8.1 cfu/m3; range, <0.8 to 42 cfu/m3) reflected the fungal load of outdoor air (9.4 cfu/m3; range, <0.8 to 50 cfu/m3), and were reduced by only about one third in rooms with portable air filtration units (5.3 cfu/m3; range, <0.8 to 41 cfu/m3). During the study period, a total of five cases (incidence density, 0.8 per 1000 patient-days) of invasive aspergillosis (one proven case, four suspected cases; case fatality rate 40%) were recorded. None of these five patients was allocated to a room with portable air filtration unit, however, the difference between incidence densities in rooms with and without portable air filtration units was non-significant (Fisher's exact test, P=0.33). Due to the noise level and thermal discomfort, patient compliance with the air filtration units was poor. We conclude that under field conditions this air filtration unit cannot be recommended for prevention of invasive aspergillosis in neutropenic haematology-oncology patients.

Summary of the Guidelines for Preventing Opportunistic Infections among Hematopoietic Stem Cell Transplant Recipients

This article contains highlights of "Guidelines for Preventing Opportunistic Infections among Hematopoietic Stem Cell Transplant Recipients: Recommendations of the CDC, the Infectious Diseases Society of America, and the American Society of Blood and Marrow Transplantation," which was published in the Morbidity and Mortality Weekly Report. There are sections on the prevention of bacterial, viral, fungal, protozoal, and helminth infections and on hospital infection control, strategies for safe living following transplantation, immunizations, and hematopoietic stem cell safety. The guidelines are evidence-based, and prevention strategies are rated by both the strength of the recommendation and the quality of evidence that supports it. Recommendations are given for preventing cytomegalovirus disease with prophylactic or preemptive gancyclovir, herpes simplex virus disease with prophylactic acyclovir, candidiasis with fluconazole, and Pneumocystis carinii pneumonia with trimethoprim-sulfamethoxazole. Hopefully, following the recommendations made in the guidelines will reduce morbidity and mortality from opportunistic infections in hematopoietic stem cell transplant recipients.

The epidemiology of invasive pulmonary aspergillosis at a large teaching hospital

OBJECTIVE

To characterize the epidemiology of invasive pulmonary aspergillosis (IPA).

DESIGN

A retrospective case series.

SETTING

An 850-bed, academic, tertiary-care medical center.

PARTICIPANTS

Adult inpatients, between January 1, 1990, and December 31, 1998, with either a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis.

METHODS

We reviewed medical records and categorized case-patients as definitive or probable and acquisition of IPA as nosocomial, indeterminate, or community using standard definitions. To determine the rate of aspergillus respiratory colonization, we identified all inpatients who had a respiratory culture positive for Aspergillus species without a histopathology report consistent with IPA or a discharge diagnosis of aspergillosis. Three study intervals were defined: interval 1, 1990 to 1992; interval 2, 1993 to 1995; and interval 3, 1996 to 1998. Carpeting in rooms for patients following heart-lung and liver transplant was removed and ceiling tiles were replaced during interval 1; a major earthquake occurred during interval 2.

RESULTS

72 case-patients and 433 patients with respiratory colonization were identified. Acquisition was nosocomial for 18 (25.0%), indeterminate for 9 (12.5%), and community-acquired for 45 (62.5%) case-patients. Seventeen (23.6%) of the 72 case-patients had prior transplants, including 15 solid organ and 2 bone marrow. The IPA rate per 100 solid organ transplants (SOTs) decreased from 2.45 during interval 1 to 0.93 during interval 2 and to 0.52 during interval 3 (chi-square for trend, 5.44; P<.05). The hospitalwide IPA rate remained stable at 0.03 per 1,000 patient days.

CONCLUSIONS

The SOT IPA rate decreased after intervals 1 and 2, although the hospitalwide IPA rate remained stable during the study period. Post-earthquake hospital demolition and construction occurring after interval 2 was not associated with an increase in the rate of IPA at our institution.

Recovery of filamentous fungi from water in a paediatric bone marrow transplantation unit

In order to determine whether water or water-related surfaces are a reservoir for opportunistic filamentous fungi, water sampling in the paediatric bone marrow transplantation (BMT) unit of the National Hospital University of Oslo, Norway was performed. During a six-month period 168 water samples and 20 samples from water-related surfaces were taken. The water samples were taken from the taps and showers in the BMT unit and from the main pipe supplying the paediatric department with water. In addition, 20 water samples were taken at the intake reservoir supplying the city of Oslo with drinking water. Filamentous fungi were recovered from 94% of all the water samples taken inside the hospital with a mean colony forming unit (cfu) count of 2.7/500mL of water. Aspergillus fumigatus was recovered from 49% and 5.6% of water samples from the taps and showers, respectively (mean 1.9 and 1.0cfu/500mL). More than one third (38.8%) of water samples from the main pipe revealed A. fumigatus (mean 2.1cfu/500mL). All water samples taken at the intake reservoir were culture positive for filamentous fungi, 85% of the water samples showed A. fumigatus (mean 3.1cfu/500mL). Twenty-five percent of water-related surfaces yielded filamentous fungi, but A. fumigatus was recovered from only two samples. We showed that filamentous fungi are present in the hospital water and to a lesser extent on water-related surfaces. The recovery of filamentous fungi in water samples taken at the intake reservoir suggests that the source of contamination is located outside the hospital.

Hospital infection control in hematopoietic stem cell transplant recipients

Guidelines for Preventing Opportunistic Infections Among Hematopoietic Stem Cell Transplant Recipients contains a section on hospital infection control including evidence-based recommendations regarding ventilation, construction, equipment, plants, play areas and toys, health-care workers, visitors, patient skin and oral care, catheter-related infections, drug-resistant organisms, and specific nosocomial infections. These guidelines are intended to reduce the number and severity of hospital infections in hematopoietic stem cell transplant recipients.

Preventing opportunistic infections after hematopoietic stem cell transplantation: the Centers for Disease Control and Prevention, Infectious Diseases Society of America, and American Society for Blood and Marrow Transplantation Practice Guidelines and beyond

This review presents evidence-based guidelines for the prevention of infection after blood and marrow transplantation. Recommendations apply to all myeloablative transplants regardless of recipient (adult or child), type (allogeneic or autologous) or source (peripheral blood, marrow or cord blood) of transplant. In Section I, Dr. Dykewicz describes the methods used to rate the strength and quality of published evidence supporting these recommendations and details the two dozen scholarly societies and federal agencies involved in the genesis and review of the guidelines. In Section II, Dr. Longworth presents recommendations for hospital infection control. Hand hygiene, room ventilation, health care worker and visitor policies are detailed along with guidelines for control of specific nosocomial and community-acquired pathogens. In Section III, Dr. Boeckh details effective practices to prevent viral diseases. Leukocyte-depleted blood is recommended for cytomegalovirus (CMV) seronegative allografts, while ganciclovir given as prophylaxis or preemptive therapy based on pp65 antigenemia or DNA assays is advised for individuals at risk for CMV. Guidelines for preventing varicella-zoster virus (VZV), herpes simplex virus (HSV) and community respiratory virus infections are also presented. In Section IV, Drs. Baden and Rubin review means to prevent invasive fungal infections. Hospital design and policy can reduce exposure to air contaminated with fungal spores and fluconazole prophylaxis at 400 mg/day reduces invasive yeast infection. In Section V, Dr. Sepkowitz details effective clinical practices to reduce or prevent bacterial or protozoal disease after transplantation. In Section VI, Dr. Sullivan reviews vaccine-preventable infections and guidelines for active and passive immunizations for stem cell transplant recipients, family members and health care workers.

A prospective study on factors influencing aspergillus spore load in the air during renovation works in a neonatal intensive care unit

The relationship between air contamination (cfu/m(3)) with fungal spores, especially Aspergillus spp., in three renovation areas of a neonatal intensive care unit (NICU) and colonization and infection rates in a high care area (HC) equipped with high efficiency particulate air (HEPA) filtration and a high pressure system, was evaluated. Data on the type and site of renovation works, outdoor meteorological conditions, patient crowding and nasopharyngeal colonization rate were collected. Factors not associated with Aspergillus spp. concentration were outdoor temperature, air pressure, wind speed, humidity, rainfall, patient density in the NICU, renovation works in the administrative area and in the isolation rooms. Multivariate analysis revealed that renovation works and air concentration of Aspergillus spp. spores in the medium care area (MC) resulted in a significant increase of the concentration in the HC of the NICU. The use of a mobile HEPA air filtration system (MedicCleanAir(R)Forte, Willebroek, Belgium) caused a significant decrease in the Aspergillus spp. concentration. There was no relationship between Aspergillus spp. air concentration and nasopharyngeal colonization in the neonates. Invasive aspergillosis did not occur during the renovation. This study highlights the importance of optimal physical barriers and air filtration to decrease airborne fungal spores in high-risk units during renovation works. The value of patient surveillance and environmental air sampling is questionable since no relationship was found between air contamination and colonization in patients.

Aspergillosis in bone marrow transplant recipients

Invasive aspergillosis in bone marrow transplant recipient is associated with a high mortality. Diagnosis is often delayed because the inflammatory response is blunted by immunosuppression. The gold standard of tissue biopsy is often considered too in invasive as the procedure is often complicated by bleeding and secondary infection. Recent finding on non-invasive tests such as serial measurement of peripheral blood galactomannan antigen or DNA appears to be promising. However, the limited availability of such tests and requirement for expertise are still hampering their use in routine clinical management. More often than not, initiation of antifungal therapy is empirical and based on suggestive radiological changes. Amphotericin B remains the gold standard of therapy but liposconal preparation may prove to be less nephrotoxic and equally effective. Treatment outcome depends more on the acceleration of the recovery of the immune system and the reduction of anti-GVHD therapy than the antifungal agent followed by surgical resection. The efficacy of many reported anti-aspergillosis prophylactic regimen has not been proved in randomized control trials. Despite the absence of data, such policy should still be considered in transplant units with high incidence of aspergillus or undergoing renovation.

Combined effects of both bacteria and gastric juice on pneumonia in mice

The effects of a combined inoculation of gastric juice and Streptococcus pneumoniae on the lungs of mice was investigated. Survival rates of mice inoculated with bacteria alone, gastric juice alone, and both bacteria and gastric juice were compared over 18 days. Xanthine oxidase (XO) activities in the lung tissues of mice inoculated with bacteria and gastric juice were measured and injected with a free radical scavenger, pyran-superoxide dismutase (pyran-SOD). A high mortality rate was observed in mice inoculated with both gastric juice and Streptococcus pneumoniae (81%). Mice inoculated with either Streptococcus pneumoniae or gastric juice showed a separate mortality rate of up to 10% during 18 days after inoculation. XO activity in the lung tissue of the mice inoculated with both gastric juice and bacteria was higher than in mice inoculated with either of them separately. The high mortality rate in the group inoculated with both two agents was reduced to 25% by the administration of pyran-SOD. XO activity raised by Streptococcus pneumoniae and gastric juice was significantly reduced by pyran-SOD. Thus, we suggest an important role in the combined effects of gastric juice and bacteria on pneumonia.

Epidemiology of nosocomial fungal infections: invasive aspergillosis and the environment

The incidence rates of invasive aspergillosis have increased dramatically during the last two decades, and, despite all diagnostic and therapeutic efforts, outcome is often fatal. Therefore, preventive measures are of major importance in the control of invasive aspergillosis, and require full understanding of the epidemiology of this devastating disease. The environment has been suggested to play a crucial role in the epidemiology of invasive aspergillosis. Aspergillus spores are released in the air and may remain airborne for prolonged periods. As a result, spores are ubiquitously found in air and contaminate anything in contact with air. It has been hypothesized that the inhalation of airborne Aspergillus spores, either directly or through intermediate nasopharyngeal colonization, is a direct cause of pulmonary infection in immunocompromised patients. Recently, water has been suggested as an additional source of "airborne" Aspergillus spp. This review summarizes the current knowledge on the role of the environment in the epidemiology of invasive aspergillosis.

Invasive aspergillosis in neutropenic patients: rapid neutrophil recovery is a risk factor for severe pulmonary complications

BACKGROUND

In invasive aspergillosis, the duration of neutropenia is an accepted risk factor, and recovery from neutropenia is generally associated with a favourable outcome. However, the rapidity of granulocyte recovery may rarely be associated with adverse sequelae. The purpose of this study was to define the relationship between neutrophil (polymorphonuclear, PMN) recovery after chemotherapy-induced bone marrow aplasia and the occurrence of severe pulmonary complications (haemoptysis, pneumothorax and death) in patients with haematological malignancies who developed invasive fungal pneumonias.

METHODS

Twenty consecutive patients were retrospectively studied; eight of them had developed pulmonary events between 5 and 11 days after neutrophil recovery that followed deep neutropenia (PMN < 100 microL-1).

RESULTS

Five patients had haemoptysis (one of these also had pneumothorax) and three had pneumothorax. According to the multiplicative logistic model, the odds of occurrence of a pulmonary event increased significantly with increasing PMN count on the fifth day (P < 0.001). Five of the eight patients who had pulmonary complications died. Also, the risk of death was larger in the presence of rapid neutrophil recovery, although the difference was not statistically significant (P = 0.111). Analysis of clinical and laboratory data showed that the risk of pulmonary complications significantly increased when the neutrophil concentration was > 4500 microL-1 on day 5 after deep granulocyte neutropenia (PMN < 100 microL-1). There was no correlation between pulmonary complications, dosage of amphotericin B and deaths.

CONCLUSION

The occurrence of life-threatening complications in patients with invasive fungal pneumonia is closely related to rapid PMN recovery.

Effects of qing fei tang (TJ-90) on aspiration pneumonia in mice

The effects of Qing Fei Tang (Sei-hai To in Japanese), a Chinese traditional medical mixture, on aspiration pneumonia were studied using mice inoculated with both Streptococcus pneumoniae and gastric juice as aspiration pneumoniae models. Daily (4 weeks) oral usage of Qing Fei Tang before inoculation reduced remarkably the mortality rate of mice. In this aspiration pneumonia model, xanthine oxidase (XO) activity in the lung tissues was elevated, but this elevation was remarkably decreased by use of Qing Fei Tang. These results suggest that Qing Fei Tang pretreatment can reduce oxygen radical production in inflammed lungs and may reduce the mortality for aspiration pneumonia.

Pulmonary Aspergillus colonization in humans and its impact on management of critically ill patients

Samples of lung tissues were obtained and analysed for Aspergillus carriage in 56 patients undergoing thoracic surgical intervention and 18 people who had an unexpected death. Out of 74 samples, 46 (63%) had evidence of pulmonary fungal colonization. The surgery population had a rate of 62% of fungal growth. Aspergillus was present in 39%. The autopsy population had a rate of 61% of fungal colonization. Aspergillus was present in 41%. In these cases eradication of fungal spores residing in the lung prior to aggressive chemotherapy and prevention of further spore uptake during hospitalization is indispensable in preventing pulmonary aspergillosis.

The epidemiology and prevention of invasive aspergillosis

Over the past two decades, the incidence of invasive aspergillosis (IA) has risen inexorably. This is almost certainly the consequence of the more widespread use of aggressive cancer chemotherapy regimens, the expansion of organ transplant programmes and the advent of the acquired immunodeficiency syndrome (AIDS) epidemic. Despite the development of new approaches to therapy, IA still remains a life-threatening infection in immunocompromised patients and is the most important cause of fungal death in cancer patients. It is clear that the prevention of severe fungal infection by the use of effective infection control measure should be the priority of the teams involved in managing at-risk patients. The evidence from clinical and molecular epidemiological studies is reviewed and current thinking on sources and routes of transmission of the organism are discussed. Our increasing understanding of these has led to the development of a variety of environmental and general strategies for the prevention of IA. It is anticipated that these, coupled with the use of prophylactic antifungal agents active against Aspergillus spp., will have a significant impact upon the morbidity and mortality associated with this infection.

Patient transport from intensive care increases the risk of developing ventilator-associated pneumonia

STUDY OBJECTIVE

To determine whether patient transport out of the ICU is associated with an increased risk of developing ventilator-associated pneumonia.

DESIGN

Prospective cohort study.

SETTING

ICUs of Barnes-Jewish Hospital, a university-affiliated teaching hospital.

PATIENTS

Five hundred twenty-one ICU patients requiring mechanical ventilation for > 12 h.

INTERVENTION

Prospective patient surveillance and data collection.

MEASUREMENTS AND RESULTS

The primary outcome measure was the development of ventilator-associated pneumonia. A total of 273 (52.4%) mechanically ventilated patients required at least one transport out of the ICU while 248 (47.6%) patients did not undergo transport. Sixty-six (24.2%) of the transported patients developed ventilator-associated pneumonia compared with 11 (4.4%) patients in the group not undergoing transport (relative risk=5.5; 95% confidence interval [CI]=2.9 to 10.1; p<0.001). Multiple logistic regression analysis demonstrated that a preceding episode of transport out of the ICU was independently associated with the development of ventilator-associated pneumonia (adjusted odds ratio=3.8; 95% CI=2.6 to 5.5; p<0.001). Other variables independently associated with the development of ventilator-associated pneumonia included reintubation, presence of a tracheostomy, administration of aerosols, and male gender.

CONCLUSIONS

We conclude that patient transport out of the ICU is associated with an increased risk for the development of ventilator-associated pneumonia.

Aspergillosis in immunocompromised paediatric patients: associations with building hygiene, design, and indoor air

BACKGROUND

Nosocomial aspergillosis is a well known complication of immunosuppression in cancer patients and those undergoing transplantation and has usually been associated with major building construction or demolition. An observational study is reported of the hospital environment associated with an outbreak of aspergillosis in a paediatric oncology ward.

METHODS

All cases of aspergillosis were identified from the hospital records and categorised as definite or probable according to the extent of supportive clinical and laboratory findings. All relevant aspects of building ventilation, air filtration, and aerosol generation considered relevant were examined and air samples for fungi were taken in triplicate at 25 sites using a slit sampler with appropriate culture media.

RESULTS

Six cases of aspergillosis were identified over one year out of the 148 patients who attended the unit - the only part of the hospital where cases were found. Examination of the building services and function suggested that the cause or source was isolated to this paediatric oncology/haematology ward and may have been attributed to a defective disposal conduit door as well as the dispersal of a contaminated aerosol from the ward vacuum cleaner which had the highest measured concentrations of Aspergillus fumigatus in or around the building (65 colony forming units (cfu)/m3 compared with 0-6 cfu/m3 elsewhere). No further cases were identified in the two years after these hygiene arrangements were changed.

CONCLUSIONS

The investigation of this outbreak of nosocomial aspergillosis identified several possible sources of fungally contaminated aerosol which could have been implicated as the cause. Their modification was followed by a reduction in the incidence of further cases. Each should be incorporated as an issue of importance in hospital building design and hygiene.

The physiologic effects of inhaled amphotericin B

Our institution used an experimental protocol for the use of inhaled amphotericin B as a prophylactic measure to prevent fungal disease in severely immunocompromised patients. We did a prospective study of the physiologic effects of amphotericin B administration. We looked specifically at oxygen saturation levels, peak flow values, and symptoms of patients given amphotericin B. We collected data on a series of 18 patients and of 132 amphotericin B administrations. Four (22%) of the patients stopped treatments because of nausea and vomiting which were believed to be due to the inhaled amphotericin B. For the remaining patients, no treatment was stopped because of symptoms or physiologic changes caused by amphotericin B, although there were 9 instances of clinically significant bronchospasm as defined by a drop in peak flow of 20% or more, 9 clinically relevant increases in cough, and 3 clinically relevant increases in dyspnea. Forty-eight percent of the clinically relevant changes occurred in patient 8. Another 16% occurred in asthmatic subjects who were significantly more likely (p = 0.03) to experience a 20% or more drop in peak flow than were patients without asthma. The physiologic profile of the response to inhaled amphotericin B is acceptable.

Epidemiology of lower respiratory tract infections

The aim of this review is to focus on the epidemiology of lower respiratory tract infections, the etiology, prognosis and risk factors, dividing these problems into the following issues: global impact of these afflictions, community-acquired pneumonia, hospital acquired pneumonia, respiratory infections in surgery, acute bronchitis and exacerbations of chronic bronchitis. Every year about 5 million people die of acute respiratory infections. Among these, pneumonia represents the most frequent cause of mortality, hospitalization and medical consultation. Several factors (age, underlying disease, environment) influence mortality, morbidity and also microbial etiology. The authors also refer to recent data on the most frequently identified antibiotic resistance of respiratory pathogens. The knowledge of such different clinico-epidemiological situations is essential to physicians for an effective approach to treatment of pneumonia and bronchitis.

Airborne nosocomial infection: a contemporary perspective

The history of airborne nosocomial infections is reviewed, and current beliefs about such infections are placed into their historical context. Possible sources, both animate and inanimate, of airborne nosocomial infections in the hospital environment are identified. Viruses, bacteria, and fungi that have been important causes of airborne nosocomial infections in the past are discussed, and examples of key studies that have confirmed an airborne route of transmission are presented. Where relevant, measures that have been used to control airborne transmission of nosocomial pathogens are discussed. Although outbreaks of airborne nosocomial infection have been uncommon, airborne transmission appears to account for about 10% of all endemic nosocomial infections.