Air pollution and health prevention: A document of reflection.

Ambient air quality, pollution and its implication on health is a topic of enormous importance that is normally dealt with by major specialists in their particular areas of interest. In general, it is not discussed from multidisciplinary approaches or with a language that can reach everyone. For this reason, the Health Sciences Foundation, from its prevention area, has formulated a series of questions to people with very varied competences in the area of ambient air quality in order to obtain a global panorama of the problem and its elements of measurement and control. The answers have been produced by specialists in each subject and have been subjected to a general discussion that has allowed conclusions to be reached on each point. The subject was divided into three main blocks: external ambient air, internal ambient air, mainly in the workplace, and hospital ambient air and the consequences of its poor control. Along with the definitions of each area and the indicators of good and bad quality, some necessary solutions have been pointed out. We have tried to know the current legislation on this problem and the competences of the different administrations on it. Despite its enormous importance, ambient air quality and health is not usually a topic of frequent presence in the general media and we have asked about the causes of this. Finally, the paper addresses a series of reflections from the perspective of ethics and very particularly in the light of the events that the present pandemic raises. This work aims to provide objective data and opinions that will enable non-specialists in the field to gain a better understanding of this worrying reality.

The impact of pipeline changes and temperature increase in a hospital historically colonised with Legionella.

Healthcare-related Legionnaires' disease has a devastating impact on high risk patients, with a case fatality rate of 30-50%. Legionella prevention and control in hospitals is therefore crucial. To control Legionella water colonisation in a hospital setting we evaluated the effect of pipeline improvements and temperature increase, analysing 237 samples over a 2-year period (first year: 129, second year: 108). In the first year, 25.58% of samples were positive for Legionella and 16.67% for amoeba. Assessing the distance of the points analysed from the hot water tank, the most distal points presented higher proportion of Legionella colonisation and lower temperatures (nearest points: 6.4% colonised, and temperature 61.4 °C; most distal points: 50% and temperature 59.1 °C). After the first year, the hot water system was repaired and the temperature stabilised. This led to a dramatic reduction in Legionella colonisation, which was negative in all the samples analysed; however, amoeba colonisation remained stable. This study shows the importance of keeping the temperature stable throughout the circuit, at around 60 °C. Special attention should be paid to the most distal points of the circuit; a fall in temperature at these weak points would favour the colonisation and spread of Legionella, because amoeba (the main Legionella reservoir) are not affected by temperature.

[Haemorrhagic exanthema due to dengue virus induced by acetylsalicylic acid]. / Exantema hemorrágico por virus dengue inducido por ácido acetil-salicílico.

Dengue fever, a viral infectious disease characteristic of tropical climates, is considered to be a re-emergent pathology responsible for several serious outbreaks in the last decade. Some factors have been involved in the spread of the virus and its vectorial mosquito carrier: human alteration of the ecosystems, improvement and speed in the transit of goods and people and climate changes. As a reflection of this, an increase in imported cases is probable, especially in tourists coming from endemic areas, considering its short period of incubation (7-10 days). The recognition of personal antecedents of journeys, the main symptoms of the disease and the potential presence of complications (haemorrhagic dengue) should be included in the examination of fever of unknown origin or feverish exanthema. The case of a patient is presented whose clinical picture of classic dengue fever was worsened by self-treatment with acetylsalicylic acid.

A distinctive cytologic pattern for diagnosing tuberculous lymphadenitis in AIDS.

Tuberculous lymphadenitis (TL) is a very common infection in human immunodeficiency virus (HIV)-infected patients. We performed fine-needle aspiration biopsy (FNAB) of enlarged lymph nodes in 57 HIV-infected patients to evaluate its usefulness in this population. We observed three cytologic patterns in 21 patients diagnosed as having TL: granulomatous lymphadenitis (GL) in 4 FNABs, necrotizing granulomatous lymphadenitis (NGL) in 7 FNABs, and necrotizing lymphadenitis (NL) in 12 FNABs. GL and NGL are already well-known and considered to be highly suggestive of TL. Our results support the idea that NL should have the same diagnostic value as GL or NGL. In the group of 12 patients with NL, TL was confirmed in 11 by microbiologic methods (7 by a positive Ziehl-Neelsen stain and 4 by a positive Löwenstein culture) and in the remaining patient by a biopsy that showed NGL with acid-fast bacilli. We conclude that FNAB is a useful, inexpensive, and safe technique for diagnosing TL in HIV-infected patients. The finding of a NL pattern is suggestive enough of TL to start antituberculous treatment.

Comparative study of the clinical presentation of Legionella pneumonia and other community-acquired pneumonias.

The aim of this study was to compare the clinical, biological, and radiologic features of presentation in the emergency ward of community-acquired pneumonia (CAP) by Legionella pneumophila (LP) and other community-acquired bacterial pneumonias to help in early diagnosis of CAP by LP. Three hundred ninety-two patients with CAP were studied prospectively in the emergency department of a 600-bed university hospital. Univariate and multivariate analyses were performed to compare epidemiologic and demographic data and clinical, analytical, and radiologic features of presentation in 48 patients with CAP by LP and 125 patients with CAP by other bacterial etiology (68 by Streptococcus pneumoniae, 41 by Chlamydia pneumoniae, 5 by Mycoplasma pneumoniae, 4 by Coxiella burnetii, 3 by Pseudomonas aeruginosa, 2 by Haemophilus influenzae, and 2 by Nocardia species. Univariate analysis showed that CAP by LP was more frequent in middle-aged, male healthy (but alcohol drinking) patients than CAP by other etiology. Moreover, the lack of response to previous beta-lactamic drugs, headache, diarrhea, severe hyponatremia, and elevation in serum creatine kinase (CK) levels on presentation were more frequent in CAP by LP, while cough, expectoration, and thoracic pain were more frequent in CAP by other bacterial etiology. However, multivariate analysis only confirmed these differences with respect to lack of underlying disease, diarrhea, and elevation in the CK level. We conclude that detailed analysis of features of presentation of CAP allows suspicion of Legionnaire's disease in the emergency department. The initiation of antibiotic treatment, including a macrolide, and the performance of rapid diagnostic techniques are mandatory in these cases.

Presence and chromosomal subtyping of Legionella species in potable water systems in 20 hospitals of Catalonia, Spain.

OBJECTIVE: To investigate the presence and clonal distribution of Legionella species in the water supply of 20 hospitals in Catalonia, Spain. SETTING: 20 hospitals in Catalonia, an area of 32,000 km2, located in northeast Spain. METHODS: Environmental cultures of 186 points of potable water supply and 10 cooling towers were performed for the presence of Legionella species. Following filtration and acid treatment, the samples were seeded in selective MWY (modified Wadowsky Yee)-buffered charcoal yeast extract-alpha agar. All isolates obtained were characterized microbiologically and genotyped by SfiI pulsed-field gel electrophoresis (PFGE). RESULTS: 73 of 196 water samples, representing 17 of the 20 hospitals included in the study, were positive for Legionella pneumophila (serogroups 1, 2-14, or both). The degree of contamination ranged from 200 to 74,250 colony-forming units/L. Twenty-five chromosomal DNA subtypes were detected by PFGE. A single DNA subtype was identified in 10 hospitals, 2 DNA subtypes were observed in 6 hospitals, and 1 hospital exhibited 3 different DNA subtypes. Each hospital had its own Legionella DNA subtype, which was not shared with any other hospitals. CONCLUSIONS: Legionella was present in the water of most of the hospitals studied; each such hospital had a unique, dominant chromosomal DNA subtype. The verification of several genomic DNA restriction profiles in such a small geographic area demonstrates the great genetic diversity of Legionella in the aquatic environment.

[Impact of control measures on the course of an outbreak of methicillin-resistant Staphylococcus aureus]. / Impacto de las medidas de control sobre la evolución de un brote epidémico por Staphylococcus aureus resistente a la meticilina.

BACKGROUND: Outbreaks of nosocomial infection by methicillin resistent Staphylococcus aureus (MRSA) are a problem in many hospitals with the control measures to be adopted being controversial. An outbreak of MRSA in a 550-bed university hospital is herein described and the impact of the adopted control measures on the evolution of the epidemic in the general hospitalization area (GHA) was analyzed. PATIENTS AND METHODS: The adopted control measures in the GHA were: microbiologic surveillance, cutaneous isolation measures, treatment of nasal carrier, and the early discharge of the cases. Hand washing was reinforced and a study of carriers was carried out on detection of sporadic cases (not related to the ICU). A molecular study of 70 strains of MRSA was performed with analysis of total plasmids, plasmid restriction pattern and chromosomic DNA analysis by pulsed field gel electrophoresis (PFGE). RESULTS: From December 1990 to December 1993, 273 cases of MRSA were reported. One hundred seventy-two cases originated in the ICU and 101 cases in the GHA (sporadic cases). The incidence of MRSA in 1991-1993 was 13.6, 14.3, and 6.6% in the ICU and 0.17, 0.36, and 0.15% in the GHA, respectively. Molecular study of MRSA isolates (1991 and 1992) demonstrated two plasmid and two chromosomic patterns. The latter had a similarity coefficient > 0.90, probably belonging to the same "clone". CONCLUSIONS: Despite the control measures adopted in the GHA the outbreak of MRSA originated in the ICU thereafter extending to the GHA. The rates of colonization detected, however, remained stable during the 3 years studied. On the other hand, the observation of a single "clone", responsible for the epidemic, suggest that most of the sporadic cases were autoctonous and due to failure in fulfillment of the established norms.

Cytopathogenicity and molecular subtyping of Legionella pneumophila environmental isolates from 17 hospitals.

The cytopathogenicity of 22 Legionella pneumophila isolates from 17 hospitals was determined by assessing the dose of bacteria necessary to produce 50% cytopathic effect (CPED50) in U937 human-derived macrophages. All isolates were able to infect and grow in macrophage-like cells (range log10 CPED50: 2.67-6.73 c.f.u./ml). Five groups were established and related to the serogroup, the number of PFGE patterns coexisting in the same hospital water distribution system, and the possible reporting of hospital-acquired Legionnaires' disease cases. L. pneumophila serogroup 1 isolates had the highest cytopathogenicity (P=0.003). Moreover, a trend to more cytopathogenic groups (groups 1-3) in hospitals with more than one PFGE pattern of L. pneumophila in the water distribution system (60% vs. 17%) and in hospitals reporting cases of hospital-acquired Legionnaires' disease (36.3% vs. 16.6%) was observed. We conclude that the cytopathogenicty of environmental L. pneumophila should be taken into account in evaluating the risk of a contaminated water reservoir in a hospital and hospital acquisition of Legionnaires' disease.

Sporadic and epidemic community legionellosis: two faces of the same illness.

The present study compares the risk factors, presentation and outcome of community-acquired Legionella pneumophila pneumonia in 138 sporadic-case patients (1994-2004) and 113 outbreak-case patients (2002) treated in two hospitals in Catalonia (Spain) since urinary antigen assays were adopted. Univariate and multivariate analysis were performed to compare epidemiological and clinical features, blood chemistry values, radiological findings and outcome of sporadic and epidemic legionnaires' disease. Univariate analysis showed that male sex, chronic lung disease, HIV infection and immunosuppressive therapy prevailed in sporadic cases. Presentation with respiratory symptoms, confusion and blood chemistry alterations, such as hyponatraemia, aspartate aminotransferase and blood urea nitrogen elevation, and partial pressure of oxygen P(O)(2) <7.98 KPa (60 mmHg) were also more frequent in sporadic cases, while headache prevailed in outbreak cases. Sporadic cases had a greater delay in treatment, were more severe and had a worse outcome than epidemic cases. Multivariate analysis showed significant differences in sex, chronic lung disease, HIV infection and headache. The clinical and outcome differences between the two groups may be explained by the detection of milder forms of legionnaires' disease, the earlier treatment and the lower severity of underlying disease in the outbreak cases.

Appearance of methicillin-resistant Staphylococcus aureus (MRSA) sensitive to gentamicin in a hospital with a previous endemic distinct MRSA.

Since 1990 a clone of gentamicin and methicillin-resistant Staphylococcus aureus (MRSA) has remained endemic in our hospital, but since January 1996 a gentamicin-sensitive strain has progressively replaced the previous clone. We characterized the phenotypic and molecular pattern of the MRSA strains isolated in our hospital in 1996 and compared prospectively the epidemiological, clinical and evolutionary characteristics of ninety patients infected or colonized by gentamicin-sensitive MRSA (GS-MRSA) (49) and by gentamicin-resistant MRSA (GR-MRSA) (41). Finally we studied the variation of aminoglycoside consumption in our hospital from 1989 to 1996. We observed two antibiotypes (GS-MRSA and GR-MRSA) corresponding to two major chromosomal patterns. Patients with GS-MRSA usually acquired the infection 72 hours after hospital admission. No significant differences were observed in epidemiological characteristics, clinical presentation and evolution between patients with GS-MRSA and GR-MRSA. Since 1989 aminoglycoside intake in our hospital has decreased by 46%.

[Bacteremia after fibrobronchoscopy. Prospective study]. / Bacteriemia posfibrobroncoscopia. Estudio prospectivo.

We prospectively evaluated in 88 inpatients the incidence of fever and bacteremia after fiberoptic bronchoscopy and its predisposing variables. Fever was present in 27% of cases and no bacteremia could be demonstrated neither associated nor intercurrent . Chronic Hepatic Disease, endobronchial pathology and bronchial biopsy practice were predisposing factors for fever development in the univariant analysis.

Factors related to persistence of Legionella urinary antigen excretion in patients with legionnaires' disease.

The aim of this prospective study was to compare patient characteristics, clinical data, and evolution of Legionella pneumophila pneumonia according to the duration of Legionella urinary antigen excretion. Urine samples from 61 patients with Legionella pneumonia diagnosed by detection of urinary antigen were obtained periodically until urinary antigen could no longer be detected. Cases were divided into two groups based on the duration of urinary antigen excretion: group I (46 patients, <60 days) and group II (15 patients, >or=60 days). Groups were compared for patient characteristics, clinical data, and evolution of pneumonia. Antigen excretion >or=60 days was observed significantly more frequently in immunosuppressed patients ( P=0.001) in whom the time to apyrexia was >72 h ( P=0.002), although only the time to apyrexia remained significant on multivariate analysis ( P=0.006). In conclusion, the duration of Legionella urinary antigen excretion was <60 days in most patients but was longer in immunosuppressed patients with a longer time to defervescence of fever.

Nosocomial and community-acquired Legionella pneumonia: clinical comparative analysis.

Previous reports have suggested that nosocomial and community Legionella pneumonia cases are similar. However, community and hospital characteristics, such as aquatic environment, antibiotic pressure (usage) and populations, are quite different, leading to the suspicion that Legionella infection may differ in the two settings. Univariate and multivariate analyses were performed to compare demographic data, risk factors, clinical, radiological and outcome data between 125 nosocomial and 33 community-acquired cases of Legionella pneumophila infection. Patients in the nosocomially acquired Legionella pneumonia (NALP) group were older than those in the community-acquired Legionella pneumonia (CALP) group. Univariate analysis showed that smoking habit, cough, thoracic pain, and extrapulmonary manifestations were more prevalent in the CALP group, whilst chronic lung disease and cancer were more prevalent in the NALP group. Moreover, patients in the NALP group were more likely to have received oxygen and corticosteroid therapy and also to have altered creatinine values than patients in the CALP group, whilst more patients in the latter group had altered alanine amino-transferase values. However, multivariate analysis failed to confirm most of these differences. Smoking habit and blood creatinine levels were the only variables remaining significant. In conclusion, demographic, clinical, laboratory, radiological and outcome data in nosocomial and community-acquired Legionella pneumonia are quite similar.