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Legionella-related disease is caused by an intracellular bacteria mainly living in water. Contamination results from inhalation of Legionella sp containing aerosolized water. Main risk factors are tobacco, immunodeficiency, and advanced age. Antigenuria is the cornerstone of the diagnosis. Immunocompromised patients, more commonly infected with non pneumophilaLegionella, present negative antigenuria, and culture and PCR are essential for the diagnosis. Legionnaires' disease may be severe, especially in elderly and/or immunocompromised patients. Mortality rate varies from 10 % in the general population to 50 % in intensive care. Treatment is based on macrolides or fluoroquinolones. Antibiotic resistance is very rare., (Copyright © 2019. Published by Elsevier Masson SAS.)

This study is the first one that describes the situation of Legionnaires' disease (LD) in Tunisia, with its clinical and epidemiological characteristics and investigates the risk factors associated with Legionella infections in our country. We conducted a retrospective multicentric study during 5 years (2008-2012) concerning all confirmed LD cases in Tunisia and we investigated risk factors for infection. The total of confirmed LD cases was 14. Incidence was 0.03. Mean age: 53.1, sex ratio (M/F): 2.6. Summer-autumnal peak was noted. Risk factors for infection were: the great humidity at home (n=4), living in community (n=3) and practice ablutions (before prayer) in public places (n=4). Community acquired legionellosis (n=9) and nosocomial (n=2). Pulmonary symptoms (n=11)+/-gastrointestinal (n=6) and/or neurological signs (n=4). Beta lactams therapy failed (n=11). CXR showed bilateral lesions (n=6). Abnormalities in laboratory values were noted: hyponatremia (n=9), high CPK levels (n=9). Diagnosis was confirmed by positive urinary Legionella antigens test (n=10) and by direct immunofluorescence (n=1). Treatment was based on bitherapy (n=10). Five patients died. The incidence of LD appears lower than other countries. Some risk factors, as ablutions, are different from that reported in Western countries and seem to be specific to our society. Given the seriousness of its consequences, it is strongly recommended to improve the national surveillance system up and register LD as notifiable disease.

Legionella is the causative agent of Legionnaires' disease, a severe form of pneumonia. Detection of Legionella pneumophila serogroup 1 antigen in urine samples has shortened the delay of diagnosis and subsequent treatment initiation resulting in decreased mortality. Improved surveillance of potable water system reinforces the community prevention. In France, the National Reference Center for Legionella collects the strains responsible for sporadic or epidemic cases and crosslinks the data including epidemiological pattern, clinical presentation, and genetic analysis of the strains. Regarding host-pathogen interactions, major advances have been made recently in the understanding of L. pneumophila ability to subvert the host intracellular trafficking and the innate immune response leading to infection control., (© 2012 médecine/sciences – Inserm / SRMS.)

Unlabelled: We performed urinary antigen tests for pneumococcus and Legionella for patients with community-acquired pneumonia (CAP), to prescribe a documented antibiotic therapy. We report the efficiency of low-spectrum antibiotic treatment, illustrating the inappropriateness of bacteriological respiratory sampling., Patients and Methods: Patients with CAP were enrolled from three different units; the pneumonia severity index was used to assess the disease. Respiratory samples were also listed. Low-spectrum antibiotic therapy was amoxicillin for pneumococcal infection, and macrolides or non-anti-pneumococcal fluoroquinolone for legionellosis., Results: Six hundred and seventy-five CAP were diagnosed during the study period,, 150 with positive urinary antigen tests (23%), among which 108 pneumococcal infections (73%), 40 legionellosis (26%), and two mixed infections. The pneumonia severity index was 106+/-38. Amoxicillin was prescribed in 108 cases, fluoroquinolone in 24 cases, macrolide in 18 cases. The outcome was favourable for 138 patients (92%). Eighty three respiratory samples allowed identification of a bacterium for 58 patients (39%), among which 24 strains were not in the antibiotic spectrum: Haemophilus influenzae and Pseudmomonas aeruginosa in six cases, Staphylococcus aureus in five cases, Klebsiella pneumoniae in two cases, and another Gram negative bacillus in five cases. These strains were resistant in vitro to the prescribed treatment in 19/24 cases (79%). One out of 12 patients who died had a respiratory sample positive for Enterobacter spp strain resistant to the ongoing antibiotic treatment., Conclusion: The low-spectrum antibiotic therapy based on urinary antigen tests is efficient, and demonstrates respiratory tract colonisation with bacteriological strains usually considered as pathogenic.

To reduce the Legionella-linked risk in the several sites of Sud-Francilien Hospital, following a hospital-acquired legionellosis case, a multidisciplinary working group performed an action plan monitored through Legionella pneumophila counts in hot water supply. From 2003 to the first half year 2009, positive points for Legionella pneumophila in the main sites of the hospital decreased from 85.71 to 28.00%, representing a significant reduction of 67.33%. Similar results were observed for three of the four establishments, whereas the last did not describe a pronounced reduction of Legionella pneumophila counts and showed constantly serogroup 1 strains. During this period, investigations of additional cases of legionellosis demonstrated a nosocomial transmission in one case in this last site. Multidisciplinary mobilization in management of Legionella-linked risk contributed to these results., (Copyright 2009 Elsevier Masson SAS. All rights reserved.)

Legionella pneumophila is a common cause of hospital and community-acquired pneumonia, being transmitted by inhalation of aqueous aerosols. Most outbreaks are linked to contaminated hot water systems and cooling towers. Our study was about the molecular typing of 35 strains of L. pneumophila including four clinical isolates and 31 environmental strains isolated from the distribution systems of 14 hotels. Among the clinical strains, two have the same pattern, however, all were different from the studied environmental strains. For the 31 environmental strains, ten patterns were obtained. Among which, a same pulsotype was found for four strains isolated from four different establishments. In addition, two different pulsotypes were found for strains isolated from the same establishment. The pulsed-field gel electrophoresis showed the existence of various patterns. Although cases of legionellosis were declared in these hotels, there are no epidemiological links between the clinical and environmental strains.

Legionnaire's disease is a recently described infection and surveillance in France was implemented in 1987. In 2005, 1,527 cases were notified corresponding to a population incidence rate of 2.5 per 100,000. The median age of cases was 61 years [5-100] and the male to female sex ratio was 3.0. The case fatality rate was 11%. One or more risk factors were identified for 1,084 (71%) cases. The majority of cases (91%) was diagnosed by urinary antigen detection and a strain was identified in 276 cases (18%). Legionella pneumophila serogroup 1 infection was confirmed in 95% of cases. A specific exposure during the incubation period was reported for 39% of cases. Travel exposure was reported for 17% and hospital exposure for 7%. Multiple clusters and outbreaks were investigated. The largest one reported was identified in the north Lyon with 34 cases. Since 1997 the incidence of LD has steadily increased. This probably suggests a better detection of cases and an improvement in the surveillance system. In recent years, several new measures concerning prevention and control were implemented. However these efforts must continue particularly in the research domain to improve knowledge of the disease, in order to limit its impact on exposed populations.

Unlabelled: Risk factors for Legionnaires' disease are well known (older age, smoking, or immunosuppression), however, the factors associated with mortality are less documented. A retrospective analysis based on cases notified between 2002 and 2004 was conducted in France to identify these factors., Method: Cases were identified through mandatory notifications sent to the Institut de veille sanitaire, France. Factors associated with mortality were identified using a logistic regression analysis., Results: Three thousand two hundred sixty-seven cases of Legionnaire's disease were notified during the study period and the evolution was documented for 85% of the cases (2.791). Three hundred seventy-seven deaths (13.5%) were notified. 72.5% of the patients were men and the median age was 61. The multivariate analysis applied to patients under 60 years revealed that cancer or hemopathy (OR=6.4 CI95% 3.6-11.2), underlying renal disease (OR=3.2 CI95% 1.0-9.9), or alcohol abuse (OR=2.2 CI95% 1.1-4.4) were associated with mortality. For older patients (>60 years) factors linked to mortality were: cancer/hemopathy (OR=1.8 CI95% 1.2-2.6), underlying renal disease (OR=3 CI95% 1.4-6.4), underlying cardiac disease (OR=2.4 CI95% 1.4-4), alcohol abuse (OR=2.4 CI95% 1.2-5.2), immunosuppression (OR=1.7 CI95% 1.1-2.6), nosocomial acquisition of the disease (OR=2.0 CI95% 1.3-3), or infection acquired in nursing home residents (OR=2.4 IC 95% 1.6-3.6)., Conclusion: These preliminary results further describe Legionnaires' disease and its mortality. However, they should be confirmed by carefully conducted prospective analysis. The description of LD patients at high risk of death will contribute to better prevention measures.

Legionnaires disease, more formally known as legionellosis, is a relatively common form of severe pneumonia caused by Legionella, a genus of waterborne bacteria. Legionellosis is acquired by inhalation of legionellae from contaminated environmental sources. Legionella pneumophila serogroup 1 is responsible for more than 80% of cases in most countries. More than 1500 cases were reported in France in 2005. Initial diagnosis is based on tests for urinary antigens. The mortality rate for legionellosis depends on the promptness of appropriate antibiotic therapy. Macrolides (erythromycin or intravenous azithromycin, which is preferred to erythromycin for its better pharmacodynamic properties) and fluoroquinolones (levofloxacin) are the antibiotics of choice for severe legionellosis.

The diagnosis of community-acquired pneumonia is usually based on clinical and radiological criteria. The identification of a causative organism is not required for the diagnosis. Although numerous microbiological techniques are available, their sensitivity and specificity are not high enough to guide first-line antimicrobial therapy. Consequently, this treatment remains most often empiric. If the causative organism is identified, the antimicrobial treatment is adapted. Sputum analysis may be proposed as a diagnostic tool for patients with an acute exacerbation of chronic obstructive pulmonary disease, in specific cases (prior antibiotherapy, hospitalization, failure of the empiric antimicrobial treatment).

Legionella pneumophila is a microorganism present in water and able to develop pneumoniae through inhalation of contaminated aerosols. Legionnaires'disease is rare (1000 cases per year in France) concerning particularly people with risk factors, but potentially with severe prognosis (lethality 15-20%). The diagnosis was recently facilitated by the introduction of urinary antigen test. Hospital is the most frequent place where L. pneumophila were acquired; however the proportion of nosocomial cases is decreasing since 2001. The associated mortality is higher for hospital acquired cases than for community acquired cases. Several official guidelines were written about prevention of legionnaires' disease. Primary prevention is essentially based on control and maintaining of water-distribution system. Secondary prevention should be a prompt response to identification of a case in order to find the source of Legionella and to protect immunocompromised persons.

Patients and Method: To describe epidemiological, clinical, biological, radiological data and therapeutic features of legionnaire's disease during an outbreak occurring in Meurthe-et-Moselle between July-August 2004., Results: 12 cases were recorded including 11 men, 6 smokers, 4 alcoholo-nicotinic, 3 diabetics, 3 with hemopathy, 1 with corticotherapy; in one case no risks factors were found; mean age was 68.5 years [minimum=48; maximum=96]. Nine cases had sudden symptoms. Nine cases had a fever up to 40 degrees C, 9 with dyspnoea, 7 with cough, 7 with a relative bradycardia, 3 with diarrhoea, 3 felt faint, 3 with confusion. Radiology: unilateral unilobe localisation in 10 cases. Biological data: cytolysis in 8 cases, CRP >300 mg/l in 8. The diagnosis confirmed with urinary antigen of Legionella pneumophila serogroup 1 (UrAgLp1) in 12 cases. In 2 cases, UrAgLp1 appeared negative between 3rd and 10th day after the beginning of a treatment although UrAgLp1 was positive before the treatment. In all cases, the first serology realised during first days following occurrence the first symptoms remained negative. Two serology of control in four were positive. One search of L. pneumophila serogroup 1 in sputum was positive in 7. Bitherapy was used in 7 cases with preferential association: fluoroquinolone+rifampicin. Two patients died. Origin of the contamination remains unknown., Conclusion: Culture of Legionella is essential, in epidemic context, to compare clinical and environmental Legionella and to locate the origin of contamination.

Since 1987, in France, Legionella infection is a notifiable disease. Notification should be transmitted by the clinician to the referent public health physician in the Direction départementale des Affaires sanitaires et sociales. Criteria for certain and probable cases have been defined. From this level, nationwide information is centralised in the institut de veille sanitaire. The public health physician is responsible for the inquiry in the health care facility or community setting and for action taking as appropriate. After isolation, Legionella strains are further studied in the Centre national de référence in Lyon. This center is also responsible for typing of environmental strains. In 2002, the incidence of notified legionellosis was 1,7 per 100,000 inhabitants and the mortality rate of 13%. Median age was 61 years and the sex-ratio M/F of 2.9. Only 39 cases were nosocomial. Very few cases have been observed in children, almost all in immunocompromised patients. Legionellosis is of exceptional occurrence in neonates, but the lethality is high. Treatment guidelines have been published in France only for adult patients.

The majority of legionellosis are caused by Legionella pneumophila, especially serogroup 1, the only diagnosed by Legionella urinary antigen test. The diagnosis of other serogroups and other Legionella species is based on culture and seroconversion. Sever cases are more frequently observed in immunocompromised patients and in nosocomial pneumonias. Each case must lead to look for the source of contamination, to detect other potential patients and permit environmental measures. Clinically and radiographically, the pneumonia is non specific except if suggestive gastro-enteric or neurologic symptoms are present. The diagnosis could be suspected in case of relative bradypnia or beta-lactamin resistance.

Purpose: Legionnaires' disease is due to the inhalation of contaminated aerosols. The identification of the source of contamination in the aquatic environment is necessary to prevent the occurrence of new cases. A comparative study of clinical and environmental isolates is the basis of epidemiological investigations., Current Knowledge and Key Points: Genotypic methods are now mainly used to compare bacterial strains. Some of these methods are based on the electrophoretic separation of DNA restriction fragments. When electrophoretic profile are complex, some fragments can be visualized after hybridization (ribotyping). Large-sized fragments can be separated by pulsed-field gel electrophoresis. Other techniques are based on gene amplification, such as AP-PCR. This technique is easy to perform but its discriminatory power and reproducibility are lower. Some procedures are combining enzymatic cleavage and gene amplification. Finally methods based on the nucleotide sequence analysis of some genes are being evaluated., Future Prospects and Projects: Techniques enabling the rapid comparison of various Legionella isolates will permit a quick detection of outbreaks and contribute to the identification of the source of contamination.

Construction and renovation projects in health care facilities are a risk for certain patients, particularly those who are immunocompromised. A proactive approach must be taken to limit construction-related nosocomial infections. This requires having a multidisciplinary team, supported by administration, to plan and implement preventive measures throughout the duration of the construction project. The ICP should be an active team member in all phases of the project. The ICP plays a major role by providing education to personnel; ensuring that preventive measures are identified, initiated, and maintained; and carrying out surveillance for infections in patients. By ensuring that the appropriate preventive measures are in place and clear lines of communication exist among the personnel, patient safety will be enhanced.

Legionelosis is an environment-related disease with particular pulmonary tropism. Reporting is mandatory in France. Legionellosis may result from nosocomial or community-acquired infection. In both cases, humans are contaminated from a humid environmental reservoir that must be identified. Cellular immunity is the main mechanism of defense and transplant recipients, particularly those on an immunosuppressor regimen, are at risk. There is no clinical, biological or radiographic sign specific of nosocomial legionellosis. Culture provides the diagnosis. Treatment is based on prevention and curative antibiotic treatment using compounds with an intracellular activity. Preventive measures have been reinforced by legislation regulating the steps required in case of nosocomial legionellosis.

The outbreak of pneumonia involving delegates to the 1976 American Legion convention at a Philadelphia hotel was the first example of travel-associated legionnaires' disease. Travel is now well known as a common risk factor for legionnaires' disease. This travel-associated disease is a preoccupation among European countries because of morbidity among citizens of the European Union. The definition of the case of legionellosis is a patient who presents an acute lower respiratory tract infection with focal signs of pneumonia and/or radiological features, and microbiological evidence of Legionella infection. A case is considered to be travel associated if the patient has spent one or more nights away from home during the ten days before becoming ill. An European Surveillance Scheme for Travel-Associated Legionnaires' Disease was established in 1987 to identify clusters and outbreaks of cases of the disease. This group centralizes the case reports of twenty-nine collaborating centres in twenty-five countries. Outbreaks of legionnaires' disease were described in hotels, camps or cruise ships. In 1996, the number of travel-associated cases of legionnaires' disease represented 16% of the total number cases. The increase of the number of reported cases may reflect improved surveillance and increased ascertainment. In Europe in 1996, the diagnosis of legionellosis was confirmed by detection of Legionella pneumophila sero-group 1 antigen in urine (36%), seroconversion (fourfold rise in antibody titre, 33%) and culture of the organism (16%). Fifteen per cent of legionellosis was diagnosed by the identification of a single high antibody titre. In France a coordination between Public Health Institutions (Réseau National de Santé Public and DDASS), clinicians, laboratories and National Reference Center was established to improve prevention and control of legionnaires' disease outbreaks. Legislation obliges to report each case. When more two cases in the same area are notified an epidemiological investigation must be done. The knowing of the source of the contamination and its eradication allows to prevent new cases and outbreaks. Outbreaks of Legionnaires' disease are even now mediatic and this fact leads to maintain attention for the quality of diagnosis and epidemiology investigation due to touristic and economic consequences for the implicated countries.

Objectives: Evaluate etiological circumstances and prognosis in Legionnaires' disease., Methods: A series of 81 culture-proven cases of Legionnaires' disease was collected in the Paris area between 1989 and 1994., Results: Direct immunofluorescence assay was positive for Legionella pneumophilia in 48% of the cases. Serogroup 1 was isolated in 88% of the cases. The median age of the patients was 51 years and 74% were males. Infection was nosocomial in 28% of the cases. Immunosuppression was present in 45% of the patients (transplantation, cancer, leukemia). Among the immunosuppressed patients, 7 were HIV-infected. Mortality due to legionellosis reached 27%. This high mortality was probably related to patient selection criteria., Conclusion: Mortality from Legionnaires' disease remains high as confirmed in this series.

Pneumonias occupy a prominent situation among lower respiratory tract infections where they are remarkable for their potential mortality and for our relative knowledge of the responsible micro-organisms. Analysis and synthesis of each series published must answer several questions, such as: what are the lung diseases considered? which investigations have been performed? which criteria of imputability have been used? in which patients has the study been carried out? in which place, which period and which structure? In spite of methodological lacunae and of the inhomogeneous answers to the questions asked, there is some concordance between the series found in the literature. Thus, more than 90% of community-acquired pneumonias with microbiological identification are caused by Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia psittaci (or pneumoniae), or Influenza A virus.

Legionella disease is among the leading causes of acute pulmonary infections. Nevertheless, the precise frequency remains difficult to assess because of its clinical aspects, the empirical treatment and the diagnostic requirements. According to the existing literature, the frequency of Legionella infections varies from 1 to 15% of documented pulmonary infections. In a survey carried out in 1990 in the Lyon area, the precise incidence of infections due to Legionella in daily medical practice has been estimated according to various types of practice. In general practice, only one case of Legionella infection was proved among 88 pulmonary infections. This weak incidence is also found in hospital practice: 10 cases among 398 hospitalized pulmonary infections in pneumology; none of 158 cases of severe pulmonary infections hospitalized in intensive care units. On the other hand, of 162 cases of hospitalized AIDS patients in a unit specialized in infections, two cases of Legionella infections were diagnosed. In a multidisciplinary 876 bed hospital, 16 cases of pulmonary infections due to Legionella were seen in 1990 by comparison with 32 cases in 1989 (chlorination of water since 1988). The data of Centre national de référence (Fleurette) report figures of 400 cases per year since 1985, without any change from one year to the other. These data are nevertheless underestimated. Global mortality is of 10%. No acquired resistance during the treatment is observed and infections caused by Legionella are consistently sensitive to macrolides, rifampicin and fluoroquinolones.(ABSTRACT TRUNCATED AT 250 WORDS)

The authors discuss the epidemiological problems of legionnaire's disease. Although Legionella is known to proliferate in watery environments, the origin and extension of sporadic cases and the factors responsible for bacterial spread remain unclear. The problem of prevention has also to be resolved.

A 71-year-old patient living in a street where major road works were taking place developed diffuse bronchopneumonia with changes in hepatic and renal biochemical tests. Since neutrophilia was moderate and all bacteriological investigations were negative, the patient was given erythromycin and was tested for antibodies directed against Legionella pneumophila. The titers of these antibodies rose from 32 to 2048 after one month. The patient was cured.

To asses the efficacy and the safety of ofloxacin as therapy of pneumonia caused by intracellular pathogens, 35 patients were studied (26 male, 9 female, mean age: 52.5 +/- 16.6 years). Causative pathogens were Chlamydia psittaci (n = 13), Legionella pneumophila (n = 10), Mycoplasma pneumoniae (n = 7) and Coxiella burnetii (n = 5). Ofloxacin was administered orally in 32 cases (200 mg b.i.d. in 80% of cases) and by I.V. route in 3 cases. All patients were cured without any side effects. In conclusion, ofloxacin appears, in our study, as an efficient therapy for these pneumonias. It could be considered as a valuable alternative to other antimicrobial agents with intra-cellular activity.

Two patients with severe forms of legionnaires' disease presented similar manifestations of a confusional syndrome, a major infectious syndrome resistant to cyclines, beta-lactams, and aminoglycosides, altered hepatic and renal functions, and a fulminating course with the need for assisted ventilation in one case. Indirect immunofluorescence serology gave very positive results in both patients and changes in serum levels were reported 6 and 8 months after the onset of the disease. A serotype I strain of Legionella pneumophila was isolated by direct immunofluorescence from bronchial aspiration products in the second case. These cases are discussed in relation to reports in the published literature.