Legionella Infections Research Articles

Sequence based typing of Legionella pneumophila sg 1 isolated in nosocomial acquired infections in Apulia, Southern Italy.

The present report aims to molecularly characterize seven clinical L. pneumophila (L. pn.) sg 1 isolated from nosocomial acquired infections in Apulia region, using the European Working Group on Legionella Infections (EWGLI), sequence-based typing (SBT) and amplified fragment length polymorphism (AFLP) protocols and to compare the identified sequence types (STs) with those available in the EWGLI database. In the period, January 2000-December 2012, 151 is cases (136 of community and 15 of nosocomial origin) of Legionnaires' disease were notified to the Regional Center for Epidemiology. With regard to nosocomial cases, 8 were confirmed by the isolation of Legionella spp. from respiratory secretions. These clinical isolates were characterized by amplified fragment length polymorphism (AFLP) and sequence-based typing (SBT), using the EWGLI standardized protocol. The clinical isolates belong to ST42, ST23 and ST1. The AFLP confirms the SBT results. Comparing the STs herein detected with those already in the EWGLI SBT database, the 3 STs are frequent in other European countries. The molecular analysis demonstrates that the 3 STs are the most frequent in Italy and in Europe, supporting the hypothesis that some specific L. pn. sg 1 clones have gained widespread dissemination probably due to a common ecological niche. Further researches are required to investigate the potential changing incidence of STs and the fitness of emerging strains or clonal groups in environmental strains.

Presence of Legionella and free-living Amoebae in composts and bioaerosols from composting facilities.

Several species of Legionella cause Legionnaires’ disease (LD). Infection may occur through inhalation of Legionella or amoebal vesicles. The reservoirs of Legionella are water, soil, potting soil and compost. Some species of free-living amoebae (FLA) that are naturally present in water and soil were described as hosts for Legionella. This study aimed to understand whether or not the composting facilities could be sources of community-acquired Legionella infections after development of bioaerosols containing Legionella or FLA. We looked for the presence of Legionella (by co-culture) and FLA (by culture) in composts and bioaerosols collected at four composting facilities located in southern Switzerland. We investigated the association between the presence of Legionella and compost and air parameters and presence of FLA. Legionella spp. (including L. pneumophila) were detected in 69.3% (61/88) of the composts and FLA (mainly Acanthamoeba, Vermamoeba, Naegleria and Stenamoeba) in 92.0% (81/88). L. pneumophila and L. bozemanii were most frequently isolated. FLA as potential host for Legionella spp. were isolated from 40.9% (36/88) of the composts in all facilities. In Legionella-positive samples the temperature of compost was significantly lower (P = 0.012) than in Legionella-negative samples. Of 47 bioaerosol samples, 19.1% (9/47) were positive for FLA and 10.6% (5/47) for L. pneumophila. Composts (62.8%) were positive for Legionella and FLA contemporaneously, but both microorganisms were never detected simultaneously in bioaerosols. Compost can release bioaerosol containing FLA or Legionella and could represent a source of infection of community-acquired Legionella infections for workers and nearby residents.

Legionella pneumophila in healthcare facilities

Legionella pneumophila are gram-negative bacteria found in freshwater environments; they can survive as intracellular parasites of free-living protozoa and within biofilms in building water systems. L. pneumophila multiply at temperatures between 25 and 42 degrees C, with an optimal growth temperature of 35 degrees C. There are 16 serogroups of L. pneumophila. In Europe, approximately 70% of Legionella infections are caused by L. pneumophila serogroup 1 and 20-30% by other serogroups. These bacteria cause respiratory disease (legionellosis) in humans when a susceptible host inhales aerosolized water containing the bacteria or aspirates water containing the bacteria. Legionellosis classically presents as two distinct clinical entities: Legionnaires' disease, a severe multisystem disease involving pneumonia, and Pontiac fever, a self-limited flu-like illness. Urine antigen tests and cultures of sputum or bronchoalveolar lavage are the most suitable clinical laboratory tests for Legionella. The new macrolide antibiotics, such as clarithromycin and azithromycin, show more effective in-vitro activity and a better intracellular and tissue penetration than erythromycin, as do the quinolones. Hospitals represent ideal locations for Legionnaires' disease transmission: at-risk individuals are present in large numbers; plumbing systems are frequently old and complex, favouring multiplication of the organism; and water temperatures are often reduced to prevent scalding of patients. Safe water is vital to ensure patient safety and reduce costs where waterborne infections cause increasing morbidity, mortality, treatment costs, longer hospital stays and compensation claims. The WHO has developed Water Safety Plans for preventing or controlling the risks through system assessment, monitoring, surveillance and management/communication, so that health outcomes can be improved, that is a systematic approach is required to secure microbial safety.

Prevalence of Legionella antibodies in immunocompromised patients

Abstract

Recreational Vehicle Water Tanks as a Possible Source forLegionellaInfections

We investigated recreational vehicle (RV) water reservoirs in response to a case of pneumonia in which Legionella pneumophila was cultured both from the patient and a RV reservoir in which he travelled. Water samples processed and cultured at the CDC according to standard protocol were positive for Legionella spp. in 4/17 (24%) faucets, 1/11 (9%) water tanks from 4/20 (20%) RVs from three different campsites. Legionella spp. that were isolated included L. pneumophila (serogroups 1 and 6), L. anisa, L. feeleii, and L. quateriensis. Environmental controls from the potable water of the three campsites were culture-negative. A survey of maintenance practices by the RV users at the campsites revealed that chlorine disinfection of the water tanks was rarely performed. To prevent the possibility of Legionella infections, RV owners should implement regular chlorine disinfection of their water tanks and follow the recommended maintenance guidelines according to their owner's manuals.

Molecular epidemiology of Legionella pneumophila serogroup 1 isolates identify a prevalent sequence type, ST505, and a distinct clonal group of clinical isolates in Toyama Prefecture, Japan

We performed comparative analyses of Legionella pneumophila serogroup (SG) 1 isolates obtained during 2005-2012 in Toyama Prefecture, Japan, by sequence-based typing (SBT) and pulsed-field gel electrophoresis (PFGE). Seventy-three isolates of L. pneumophila SG 1, including 17 isolates from patients, 51 from public baths, 4 from cooling towers, and 1 from a shower, were analyzed. The isolates were classified into 43 sequence types (STs) by SBT and 52 types by PFGE. Fourteen STs were unique to Toyama Prefecture, as determined from the SBT database of European Working Group for Legionella Infections (EWGLI), as of October 31, 2012. ST505 strain was identified in 4 isolates from patients and 5 isolates from public baths, and these isolates belonged to 2 PFGE types. These, however, were similar because of the difference with only two restriction fragments, indicating that ST505 strain was prevalent among L. pneumophila SG 1 isolates in this area. ST505 strains isolated from patients and public baths were distributed along the river in a western part of Toyama Prefecture. SBT and PFGE profiles of 3 clinical isolates were identical with those of 3 environmental isolates from the suspected origins of the infection in each case, respectively. This finding suggested that SBT and PFGE were useful for epidemiological study. Furthermore, by SBT analysis, we identified a clonal group formed only by 7 clinical isolates that are not associated with bathwater, suggesting that they were derived from unrecognized sources.

Sequence-based typing of Legionella pneumophila serogroup 1 clinical isolates from Belgium between 2000 and 2010

Sequence-based typing (SBT) is a discriminatory method widely used to genotype Legionella pneumophila strains. A total of 86 clinical L. pneumophila serogroup 1 (sg1) isolates, collected between January 2000 and December 2010 in the two Belgian National Reference Centres for Legionella pneumophila, were genotyped using the internationally standardised SBT protocol of the European Working Group for Legionella Infections (EWGLI). The isolates could be classified into 31 different sequence types (ST, index of diversity: 0.879). The obtained STs were submitted to the EWGLI SBT-database for L. pneumophila. In our study, ST47 (27.9%) and ST1 (19.8%) were the most frequently detected STs. The detected profiles were a combination of both frequently isolated and unique STs, and of both worldwide distributed and more local strains. Two STs, ST880 and ST881, were new to the EWGLI database. In conclusion, we characterised L. pneumophila sg1 isolates with the SBT method, and created a Belgian profile database that will be useful for future epidemiological studies.

Epidemiological investigation of a legionellosis outbreak in a Slovenian nursing home, August 2010

August 2010 marked the beginning of the largest outbreak of legionellosis in a Slovenian nursing home. This article presents our experiences with the outbreak investigation. In order to collect the necessary patient epidemiological data, we used individual epidemiological questionnaires. Samples were available from 15 patients and were subject to laboratory investigation. Urine and sputum samples were difficult to obtain due to the underlying diseases of the patients. Serological diagnostics constituted an important part of the epidemiological investigation. Sixty-four environmental samples were taken to identify the sources of infection. By genotyping, we assessed the affinity of the allelic profile of Legionella pneumophila serogroup 1 in environmental samples and in patient samples. Legionnaires' disease was diagnosed in 10 patients based on a combination of various tests. Legionella pneumophila serogroup 1, Legionella pneumophila serogroups 2-14, and Legionella sp., in concentrations of < 10 to 61,000 CFU/l, were isolated from 51 out of 64 environmental samples. The source of the outbreak was confirmed by genotyping the isolates from patients and the isolates from the water supply system. The 2 isolates had identical allelic profiles corresponding to that of L. pneumophila serogroup 1 allelic profile 2,3,9,10,2,1,6, designated sequence type 23 (according to the European Working Group for Legionella Infections). We describe a Legionella pneumophila serogroup 1 outbreak in a Slovenian nursing home. The source of infection was demonstrated using sequence-based typing. Water flow disturbances were determined as the most probable cause of Legionella growth. Overall, the risk of a Legionella outbreak is underestimated in Slovenia.

An Outbreak of Legionnaires Disease Associated with a Decorative Water Wall Fountain in a Hospital

To detect an outbreak-related source of Legionella, control the outbreak, and prevent additional Legionella infections from occurring. Epidemiologic investigation of an acute outbreak of hospital-associated Legionnaires disease among outpatients and visitors to a Wisconsin hospital. Patients with laboratory-confirmed Legionnaires disease who resided in southeastern Wisconsin and had illness onsets during February and March 2010. Patients with Legionnaires disease were interviewed using a hypothesis-generating questionnaire. On-site investigation included sampling of water and other potential environmental sources for Legionella testing. Case-finding measures included extensive notification of individuals potentially exposed at the hospital and alerts to area healthcare and laboratory personnel. Laboratory-confirmed Legionnaires disease was diagnosed in 8 patients, all of whom were present at the same hospital during the 10 days prior to their illness onsets. Six patients had known exposure to a water wall-type decorative fountain near the main hospital entrance. Although the decorative fountain underwent routine cleaning and maintenance, high counts of Legionella pneumophila serogroup 1 were isolated from cultures of a foam material found above the fountain trough. This outbreak of Legionnaires disease was associated with exposure to a decorative fountain located in a hospital public area. Routine cleaning and maintenance of fountains does not eliminate the risk of bacterial contamination. Our findings highlight the need to evaluate the safety of water fountains installed in any area of a healthcare facility.

Wild-type MIC distribution and epidemiological cut-off values in clinical Legionella pneumophila serogroup 1 isolates

ObjectivesThe purpose of this study was to establish wild-type (WT) distributions and determine the epidemiological cut-off values (ECOFF) in clinical L. pneumophila serogroup 1 isolates for 10 antimicrobials commonly used for the treatment of Legionella infections using a method feasible in a routine clinical laboratory. MethodsMICs of 183 clinical L. pneumophila serogroup 1 isolates, collected as part of an outbreak detection program, were tested using E-test methodology on buffered charcoal yeast extract agar supplemented with α-ketoglutarate (BCYE-α). The MICs were read after 2 days of incubation at 35 °C with increased humidity and without CO2. ECOFFs were determined according to EUCAST methodology and expressed as WT ≤ X mg/L. ResultsAll antimicrobials showed a WT distribution, although the width varied from 2 two-fold dilutions to 8 dilutions, depending on antibiotic class. The ECOFFs determined were 1.0 mg/L for ciprofloxacin, 0.50 mg/L for levofloxacin, 1.0 mg/L for moxifloxacin, 1.0 mg/L for erythromycin, 1.0 mg/L for azithromycin, 0.50 mg/L for clarithromycin, 1.0 mg/L for cefotaxime, 0.032 mg/L for rifampicin, 16 mg/L for tigecycline, and 8 mg/L for doxycycline. ConclusionAll isolates were inhibited by low concentrations of the fluoroquinolones and macrolides tested, with somewhat higher MICs for the fluoroquinolones. Rifampicin was found to be the most active against L. pneumophila isolates in vitro. These data can be used as a reference for the detection of resistance in clinical L. pneumophila isolates and as a setting of clinical breakpoints.

Respiratory failure presenting in H1N1 influenza with Legionnaires disease: two case reports

IntroductionMedia sensationalism on the H1N1 outbreak may have influenced decisional processes and clinical diagnosis.Case PresentationWe report two cases of patients who presented in 2009 with coexisting H1N1 virus and Legionella infections: a 69-year-old Caucasian man and a 71-year-old Caucasian woman. In our cases all the signs and symptoms, including vomiting, progressive respiratory disease leading to respiratory failure, refractory hypoxemia, leukopenia, lymphopenia, thrombocytopenia, and elevated levels of creatine kinase and hepatic aminotransferases, were consistent with critical illness due to 2009 H1N1 virus infection. Other infectious disorders may mimic H1N1 viral infection especially Legionnaires' disease. Because the swine flu H1N1 pandemic occurred in Autumn in Italy, Legionnaires disease was to be highly suspected since the peak incidence usually occurs in early fall. We do think that our immediate suspicion of Legionella infection based on clinical history and X-ray abnormalities was fundamental for a successful resolution.ConclusionOur two case reports suggest that patients with H1N1 should be screened for Legionella, which is not currently common practice. This is particularly important since the signs and symptoms of both infections are similar.

Plan for the control of Legionella infections in long-term care facilities: Role of environmental monitoring

In accordance with the international and national guidelines, the Emilia-Romagna Region (Italy) has established regional guidelines for the surveillance and prevention of legionellosis based on the concept of risk assessment, with particular attention to environmental monitoring. The aim of this study was to verify how environmental surveillance in the context of risk assessment plans could help to guide decisions about preventive strategies against Legionella infections in Long Term Care Facilities (LTCF). In six LTCFs in the city of Bologna (Emilia-Romagna Region) a self-control plan was implemented that included the environmental monitoring of Legionella spp. and the surveillance of hospital-acquired Legionnaires' Disease. At baseline, four hot water systems were colonized by Legionella pneumophila (3 LCTFs) and Legionella londiniensis (1 LCTF). In each establishment specific control measures were adopted based on the characteristics of the system, the virulence of the strain and the level of the contamination. The monitoring, carried out for around two years, was also extended to the ways in which the system and the distal water distribution points were used and maintained with respect to the good practices in operation and management. The adopted actions (shock and/or continuous disinfection treatments) and the implementation of the good practice measures reduced the contamination to acceptable and stable levels. No cases of hospital-acquired legionellosis occurred during the period of study. The environmental surveillance was successful in evaluating the risk and identifying the most suitable preventive strategies.

Legionellen im Trinkwasserbereich

Although much is known about Legionella and the illness they cause, the relationship between their concentration in water and the risk of infection remains unclear. A comprehensive body of experience shows that the growth of Legionella in heated water distribution systems can be effectively controlled by following the preventive measures described in the generally acknowledged codes of practice. As orientation to trigger action, a technical action level of 100 colony-forming units in 100 ml water has found wide acceptance as the maximally tolerable concentration of Legionella in drinking water hygiene. However, this value as well as the concept for controlling the growth of Legionella in installations has developed historically. In part, the focus differs between drinking water hygiene and hospital hygiene. Also, there is no harmonized European approach for controlling Legionella. In spite of such differences, there are important international parallels in the assessment of the occurrence of Legionella, in experience with controlling them, and in recommendations for prevention. There is a need particularly for adequate studies to clarify the risk of infection as well as for the publication of existing data and experience showing the efficacy of measures for prevention, disinfection and system upgrading. Such data are necessary to support evidence-based prevention of Legionella infections and to create a better epidemiological data base in Germany. One chance for reaching this target would be to improve practices in diagnosis, reporting and central data evaluation—not only of illness, but including also data on Legionella occurrence. More frequent Legionella testing of pneumonia patients is a prerequisite for this, but particularly also for the rapid identification and removal of the source of infection. Further requirements include better training of planers, plumbers, and operators of drinking water installations about the approach to preventing Legionella contamination of drinking water installations described in standards and guidelines. The further development of practicable concepts for effective Legionella prevention requires good collaboration between public authorities responsible for drinking water and hospital hygiene on the federal and state levels and experts for the prevention of infection, hygiene, and sanitary installations.

Legionella pneumophila

Legionellae are environmental bacteria that can be frequently isolated from technical water supply systems. The most prevalent species is Legionella pneumophila, especially serogroup 1. In the environment, legionellae multiply in amoebae. Since Legionella pneumonias cannot be distinguished from pneumonias caused by other microbial pathogens, special microbiological tests, e.g., urinary antigen assays, are essential to detect Legionella infections. All water supply systems to which the patient is exposed during the incubation time of 2 to 10 days might be the source of the infection. This can be confirmed or excluded by molecular typing of isolates from patients and the environment. The most commonly used techniques are monoclonal antibody typing and sequence-based typing (SBT). Some sequence types (ST) are frequently found among clinical strains but are seldom isolated from the environment, e.g., ST 23, 42, 47, 62, and 146. It is safe to assume that such strains are highly virulent. Conversely, it does not seem to be justified to dedicate the same awareness to all environmental Legionella strains.

Epidemiologie und Erreger bei ambulant erworbener Pneumonie (CAP)

Community-acquired pneumonia is a frequent disease. Case-fatality rate and incidence are increasing with age. The German nation-wide competence network CAPNETZ presents reliable data on aetiology and course of the disease, based on more than 9000 prospectively observed patients. This review discusses current CAPNETZ-publication and their impact on daily clinical practice. The most frequent isolated pathogen isolated was STREPTOCOCCUS PNEUMONIAE. According to CAPNETZ results, the importance of atypical pathogens (i. e. Mycoplasma spp., Chlamydia spp., Legionella spp.) may have been overestimated in older studies: CHLAMYDIA PNEUMONIAE (< 1 %) are rarely found, and the most frequent atypical pathogen, Mycoplasma spp., causes only mild disease in younger patients resulting in a very low case-fatality-rate (0.7 %). Only hospitalized patients with legionella infections are at an increased risk to die. Gram-negative ENTEROBACTERIACEAE and PSEUDOMONAS AERUGINOSA are rare, restricted to high-risk patient groups (e. g. mulitmorbidity, enteral tube feeding), but are associated with an increased case-fatality rate.

Evaluation of a rapid immunochromatographic assay for the detection and identification of Legionella spp. strains isolated from cultures

The Legionnaires’ disease is a major issue in the healthcare because it ranks among the emerging infectious diseases in our country, particularly those caused by Legionella pneumophila serogroup 1. The severity of the infection is related to several factors including the virulence of the bacterium and the immune status of patient. Since the clinical diagnosis of Legionella infections or pneumonia with different etiology is extremely difficult, the use of new diagnostic techniques in rapid identification plays a key role. The aim of our study was to evaluate the performance of a new immunochromatographic assay can detect and identify strains of Legionella spp. from the cultures.

Activities of tigecycline and comparators against Legionella pneumophila and Legionella micdadei extracellularly and in human monocyte-derived macrophages

The activity of tigecycline against Legionellae, which are intracellular pathogens, was evaluated intracellularly in human phagocytes and extracellularly, and compared to the activities of erythromycin and levofloxacin. Clinical isolates of L. pneumophila serogroups 1, 5, and 6 and L. micdadei were tested in time-kill experiments. Extracellular experiments were done using buffered yeast extract broth. For intracellular assays, monolayers of human monocyte-derived macrophages (MDM) were infected with L. pneumophila or L. micdadei. Antibiotics (0.05–2.5 × MIC) were then added. MDM were lysed at 0, 24, 48, and 72 h and viable bacteria in the lysates were enumerated. Based on multiples of the MICs, tigecycline was less active extracellularly than levofloxacin or erythromycin. However, intracellular killing of both L. pneumophila and L. micdadei by tigecycline at 72 h was greater than for erythromycin or levofloxacin. Currently, evidence does not support the use of tigecycline as a first-line drug for treatment of Legionella infections. However, since Legionellae are intracellular pathogens, these results suggest that tigecycline should be effective for treatment of infections caused by these bacteria.

Travel-associated Legionnaires’ disease in Europe in 2009

A total of 818 cases of Legionnaires' disease with onset of illness in 2009 were reported from 22 European and two non-European countries to the European Surveillance Scheme for Travel-Associated Legionnaires' Disease (EWGLINET). This is a decrease of 52 cases compared with 2008 and 129 fewer than in 2007 - the peak year of reporting to date. A total of 794 (97.1%) cases were reported as confirmed and 24 as presumptive cases. Outcome of illness was reported for 561 (68.6%) cases. Of these cases 28 (5%) were reported to have died. More than half, of the cases in 2009 (n=469, 57.3%) were reported within 20 days of symptom onset. Cases visited 53 countries and were infected in all months of the year, with a peak in September (n=146). By country of residence of the cases, the United Kingdom (UK) reported the highest number of cases (n=173). Italy reported the second highest number of cases (n=169) and was also the country associated with the most cases by country of infection (n=209). A total of 88 new clusters (75 in Europe and 13 outside Europe) were detected in 2009 and were associated with 196 cases. The largest cluster occurred in Italy and involved seven cases. Without the scheme's international database, thirty three (37.5%) of the newly detected clusters would not have been identified. In 49 of the accommodation sites with clusters of cases, environmental samples were found to be positive for Legionella spp. Details of 10 sites were published on the European Working Group for Legionella Infections (EWGLI) website for failure to return information on the status of environmental investigations.

Distribution of Legionella species from environmental water sources of public facilities and genetic diversity of L. pneumophila serogroup 1 in South Korea.

A total of 560 Legionella species were isolated from environmental water sources from public facilities from June to September 2008 throughout South Korea. The distribution of Legionella isolates was investigated according to geographical region, facility type, and sample type. The genetic diversity of 104 isolates of Legionella pneumophila serogroup 1 (sg 1) was analyzed by sequence-based typing (SBT). L. pneumophila was distributed broadly throughout Korea, accounting for 85.0% of the isolates, and L. pneumophila sg 1 predominated in all of the public facilities except for the springs. Legionella anisa and Legionella bozemanii predominated among non-L. pneumophila species (48.1% and 21.0%, respectively). The second most dominant strain differed depending on the facility type: L. anisa was the second most dominant strain in the buildings (10.8%), L. pneumophila sg 5 in public baths (21.6%), L. pneumophila sg 6 in factories (12.0%), and L. pneumophila sg 7 in hospitals (13.1%). In the SBT analysis, 104 L. pneumophila sg 1 isolates were differentiated into 26 sequence types (STs) and categorized into 3 clonal groups (CGs) and 10 singleton STs via the eBURST V3 program. ST1, a potential founder of major CG1, was commonly distributed (48.1%). The dominant ST in hot water was ST-K1 (7, 12, 17, 3, 35, 11, 11), which was designated in this study (36.1%). The second most dominant strain differed depending on the type of facility from which the samples were obtained. The unique allelic profile of ST-K1, obtained from hot water, was not found in the European Working Group for Legionella Infections (EWGLI) SBT database.

Legionella infections and travel associated legionellosis

Travel associated Legionnaires' disease represents a significant cause of travel associated respiratory tract infections and impacts disproportionately on otherwise healthy individuals as a consequence of their travel abroad or within their own country. Because of the propensity of these bacteria to colonize man-made water systems, legionellosis are frequently reported in travelers who stayed in accommodations sites such as hotels or cruise ships. Since the discovery of this new pathogen and the creation of surveillance networks, the number of reported travel associated legionellosis cases have increased regularly. Education of physicians about the association of Legionnaires' disease with travel and the use of appropriate diagnostic tests and therapy can result in a reduction in morbidity and mortality due to this important cause of community-acquired pneumonia.