In Vitro and Intracellular Activities of Omadacycline against Legionella pneumophila.

Omadacycline is an aminomethylcycline antibiotic with in vitro activity against pathogens causing community-acquired bacterial pneumonia (CABP). This study investigated the activity of omadacycline against Legionella pneumophila strains isolated between 1995 and 2014 from nosocomial or community-acquired respiratory infections. Omadacycline exhibited extracellular activity similar to comparator antibiotics; intracellular penetrance was found by day 3 of omadacycline exposure. These results support the utility of omadacycline as an effective antibiotic for the treatment of CABP caused by L. pneumophila.

Heated birthing pools as a source of Legionnaires' disease.

In June 2014 Public Health England confirmed a case of Legionnaires' disease (LD) in a neonate following birth at home in a hired birthing pool incorporating a heater and a recirculation pump which had been filled in advance of labour. The case triggered a public health investigation and a microbiological survey of an additional ten heated birthing pools hired or recently hired to the general public across England. The birthing pool used by the parent of the confirmed case was identified as the source of the neonate's infection following detection of Legionella pneumophila ST48 in both patient and environmental samples. Legionella species were detected by quantitative polymerase chain reaction but not culture in a further three pools together with other opportunistic pathogens identified by culture and matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry. A Patient Safety Alert from NHS England and Public Health England was issued stating that heated birthing pools filled in advance of labour should not be used for home births. This recommendation remains in place. This investigation in conjunction with other recent reports has highlighted a lack of awareness regarding the microbiological safety of heated birthing pools and their potential to be a source of LD and other opportunistic infections. Furthermore, the investigation raised important considerations with regards to microbiological sampling and testing in such incidents. Public health authorities and clinicians should consider LD in the differential diagnosis of severe respiratory infection in neonates within 14 days of a water birth.

Necessity and effect of combating Legionella pneumophila in municipal shower systems.

The objective was to obtain research-based, holistic knowledge about necessity and effect of practiced measures against L. pneumophila in municipal shower systems in Stavanger, Norway. The effects of hot water treatment and membrane-filtering were investigated and compared to no intervention at all. The studies were done under real-world conditions. Additionally, a surveillance pilot study of municipal showers in Stavanger was performed. The validity of high total plate count (TPC) as an indication of L. pneumophila was evaluated. A simplified method, named "dripping method", for detection and quantification of L. pneumophila was developed. The sensitivity of the dripping method is 5 colony-forming units of L. pneumophila/ml. The transference of L. pneumophila from shower water to aerosols was studied. Interviews and observational studies among the stakeholders were done in order to identify patterns of communication and behavior in a Legionella risk perspective. No substantial effects of the measures against L. pneumophila were demonstrated, except for a distally placed membrane filter. No significant positive correlation between TPC and L. pneumophila concentrations were found. L. pneumophila serogroup 2-14 was demonstrated in 21% of the 29 buildings tested in the surveillance pilot. Relatively few cells of L. pneumophila were transferred from shower water to aerosols. Anxiety appeared as the major driving force in the risk governance of Legionella. In conclusion, the risk of acquiring Legionnaires' disease from municipal shower systems is evaluated as low and uncertain. By eliminating ineffective approaches, targeted Legionella risk governance can be practiced. Risk management by surveillance is evaluated as appropriate.

Case of Legionnaires disease in a neonate following a home birth in a heated birthing pool, England, June 2014.

Public Health England was notified of Legionnaires' disease in a neonate following a home birth in a heated birthing pool filled from the domestic hot water supply two weeks earlier. We describe the incident, sampling results, and public health actions. It is recommended that heated birthing pools should not be used for home births. Neonates developing pneumonia within 14 days of labour or birth in any birthing pool should be tested for Legionnaires' disease.

Legionella pneumophilla bacteria in thermal saline bath.

OBJECTIVE: The study was aimed at determining whether Legionella pneumophila bacteria can be found in thermal saline waters used in balneotherapy. METHODS: Water samples were collected from three thermal saline baths, supplied by thermal saline waters (type Cl - Na). The total number of bacteria was determined in the direct microscopic count under a fluorescence microscope The numbers of bacteria belonging to different phylogenetic groups (Eubacteria, Legionella sp. and Legionella pneumophila) were determined with the use of a molecular FISH method. RESULTS: The highest average total number of bacteria as well as the highest average number of Eubacteria in the entire research cycle was recorded in bath 1. Bacteria belonging to the Legionella genus along with Legionella pneumophila were identified in all water samples collected from each bath. Moreover, biofilm containing cells of L. pneumophilla was identified in the collected water samples. CONCLUSION: The number of bacteria in water increases with the bath's age. The Legionella pneumophila can successfully develop not only in fresh water bodies but in thermal saline baths as well. Still, it is uncertain whether the commonly applied culture method, developed for freshwater bodies, is also suitable for thermal saline baths.

Distribution of Legionella pneumophila bacteria and Naegleria and Hartmannella amoebae in thermal saline baths used in balneotherapy.

The present study was aimed at investigating the coexistence and interactions between free living amoebae of Naegleria and Hartmannella genera and pathogenic Legionella pneumophila bacteria in thermal saline baths used in balneotherapy in central Poland. Water samples were collected from November 2010 to May 2011 at intervals longer than 1 month. The microorganisms were detected with the use of a very sensitive fluorescence in situ hybridisation method. In addition, the morphology of the amoebae was studied. Despite relatively high salinity level, ranging from 1.5 to 5.0 %, L. pneumophila were found in all investigated baths, although their number never exceeded 10(6) cells dm(-3). Hartmannella were not detected, while Naegleria fowleri were found in one bath. The observation that N. fowleri and L. pneumophila may coexist in thermal saline baths is the first observation emphasising potential threat from these microorganisms in balneotherapy.

Comparison of the plating efficiencies and shelf lives of three different commercial buffered charcoal yeast extract media supplemented with alpha-ketoglutaric acid.

The plating efficiencies and shelf lives of locally made buffered charcoal yeast extract medium supplemented with alpha-ketoglutaric acid (BCYEalpha) were compared to those of media made by BD, Hardy, and Remel. Lung homogenates from guinea pigs infected with Legionella pneumophila were plated monthly onto different medium lots. All media performed equally well and had shelf lives of at least 12 months.

Baja mortalidad en un brote de enfermedad del legionario: correlación con el estudio de citopatogenicidad / Low mortality rate in an outbreak of Legionnaires’ disease: Correlation with the cytopathogenity study

Fundamento y objetivo: En el año 2001 tuvo lugar en Murcia un brote de enfermedad del legionario (EL) con una de las tasas de mortalidad más bajas conocidas. Los objetivos de este estudio fueron describir la presentación clínica y los resultados de los estudios molecular y de virulencia de los aislamientos clínicos de Legionella para correlacionar la baja mortalidad de la serie con la virulencia de la cepa. Pacientes y método: Estudio prospectivo y descriptivo de un brote de EL en un subgrupo de 86 pacientes. Se analizan datos demográficos, factores de riesgo y evolución clínica. Se ha practicado subtipificación molecular mediante electroforesis en campo pulsátil y estudio de citopatogenicidad de los aislamientos clínicos y se han comparado con los de aislamientos procedentes de otros brotes. Resultados: La edad media fue de 58,2 años, con predominio del sexo masculino (77,9%). El tabaquismo fue el factor de riesgo más frecuente (71,7%). El 70,2% de los pacientes presentaba enfermedades de base. Las manifestaciones clínicas, los datos de laboratorio y la radiología fueron compatibles con un cuadro de neumonía atípica. La mortalidad fue del 3,2%. Todos los aislamientos clínicos de Legionella pneumophila mostraron el mismo subtipo molecular. En el estudio de citopatogenicidad, las cepas de Legionella procedentes del brote se incluyeron dentro del grupo de menor virulencia. Conclusiones: En este subgrupo de pacientes predominaron el sexo masculino, el tabaquismo, la presentación clínica compatible con neumonía atípica y la baja mortalidad. La baja virulencia de este genotipo molecular de L. pneumophila podría ser causante, en parte, de la baja mortalidad observada en el brote de Murcia (AU)

Background: In 2001 an outbreak of Legionnaires’ diseases occurred in Murcia, Spain, with one of the lowest known rates of associated mortality. We describe the clinical data of a subgroup of patients, and present the results from molecular and virulence studies to correlate the lower mortality of the overall series with the strain virulence. Patients and methods: A subgroup of 86 patients from the outbreak of Legionnaires’disease was prospectively included. Demographic, risk factors and clinical evolution data were obtained. Moreover, we performed a pulsed field gel electrophoresis and cytopathogenicity assay of the Murcia outbreak that were compared with other unrelated Legionella isolates. Results: Sixty-nine (77.9%) patients were males. The mean age of the patients was 58.2 years (range: 32–87). Smoking was the most frequent risk factor in 62 patients (71.7%) and 61 patients (70.2%) had underlying diseases. Clinical, laboratory and radiological manifestations were compatible with the atypical pneumonia syndrome. The mortality rate was 3.2%. All the clinical L. pneumophila isolates analyzed by PFGE showed the same subtype. When analyzing theses strains together with other Legionella strains, they were included in the group with lower virulence in the cytopathogenicity study. Conclusions: The most outstanding data in this subgroup of patients were: male-sex, smoking, atypical clinical manifestations and low mortality. The low virulence of this molecular genotype of L. pneumophila may be responsible, in part, for the low mortality observed in the outbreak in Murcia (AU)

[Therapeutic efficacy of levofloxacin against a model of replicable Legionella pneumophila lung infection in DBA/2 mice].

The in vitro and in vivo antibacterial activities of levofloxacin (LVFX), a quinolone antibacterial, against clinically isolated Legionella pneumophila were investigated in comparison with those of existing antimicrobial agents approved for legionnaires disease. The minimum inhibitory concentrations (MICs) of the agents against 42 strains of L. pneumophila isolated in Japan were determined using agar dilution methods with buffered starch yeast extract agar. MIC90 of LVFX was 0.03 microg/ml and this activity was similar to ciprofloxacin and pazufloxacin, and higher than telithromycin and minocycline. Therapeutic efficacy of LVFX was studied against a pneumonia model induced by intranasal of L. pneumophila strain suzuki serogoup 1 in DBA/2 mice. Therapeutic doses in mice were selected that would closely match human exposure profile, area under the concentration-time curve (AUC) for a human oral dose of LVFX at 500 mg once a day. LVFX decreased significantly the bacterial burden in the lungs from the next day of commencing treatment. These results, including in vitro antibacterial activity against clinical isolates and therapeutic efficacy of a humanized dosing regimen, provide good evidence to support the use of LVFX at 500 mg once a day for treating patient with legionnaires disease.

Molecular epidemiology of Legionella pneumophila serogroup 1 isolates following long-term chlorine dioxide treatment in a university hospital water system.

This paper describes the results of a five-year monitoring programme applied to the water distribution system of the University Hospital of Pisa (Italy). The purpose of the programme was to evaluate the efficacy of an integrated water safety plan in controlling Legionella spp. colonisation of the potable water system. The impact of the safety plan on the ecology of legionella in the water network was evaluated by studying the genetic variability and the chlorine susceptibility of the strains isolated prior to, and throughout, the application of continuous chlorine dioxide treatment. After 45 months of water hyperchlorination, Legionella spp. were still present but the positive supply points were reduced by 79.4%. The samples exceeding 10(3)cfu/L were reduced by 83.8% and the mean counts showed a decrease of 94.6%. The majority of the isolates belonged to Legionella pneumophila serogroup 1 (overall positivity rate: 161/423; 38%). Molecular typing was performed on 61 isolates (37.9% of the positive samples) selected on spatial and temporal criteria. This revealed the circulation and the persistence in the hospital environment of three prevalent types of L. pneumophila Wadsworth, demonstrating allelic and electrophoretic characteristic profiles and different chlorine susceptibility. Two of these, one predominant and pre-dating the sanitation regimen, and one other isolated after three years of water treatment, were chlorine tolerant. Despite the ineffectiveness of chlorine dioxide in eradicating L. pneumophila, the risk management plan adopted appeared to discourage further cases of nosocomial legionellosis.

An outbreak of Legionella pneumophila suspected to be associated with spa pools on display at a retail store in New Zealand.

AIM: To investigate and characterise a cluster of six cases of severe pneumonia in the Wellington region notified to Regional Public Health in November 2003. And to describe the public health response to an identified subgroup of Legionella infections. METHODS: The case definition was "a person admitted to Wellington or Hutt Hospital between 29 October 2003 and 9 November 2003 with severe pneumonia". The cluster was initially investigated by interviewing patients to obtain histories of activities and exposures, and by reviewing medical notes. Medical teams sent further clinical specimens for testing (sputum for polymerase chain reaction [PCR], convalescent Legionella serology, and urine for Legionella antigen testing). Further investigation of Legionella pneumophila cases involved obtaining detailed exposure histories, environmental investigations at the suspect source of infection, and taking water and biofilm swabs for Legionella detection and serotyping. RESULTS: Three cases from the cluster were confirmed as, or compatible with, Legionella pneumophila serogroup 2. With the other three cases there was evidence of infection with L. longbeachae (two cases) or respiratory syncytial virus (one case). Exposure histories for the L. pneumophila cases revealed that the three cases had visited a Lower Hutt retail outlet with operating spa pools on display. Legionella pneumophila serogroup 1 was cultured from one of three pools. All pools were positive for Legionella on direct fluorescent antibody testing. CONCLUSIONS: Although unproven, the display spa pools were considered to be the most likely source of Legionella infection in the three cases that had visited the retail outlet. Although Legionella isolated from the pools was a different serogroup from that identified in two cases, the pools were considered to be the most likely source of infection in view of inadequate chlorination of the waters. Public health intervention to address the immediate and longer-term health risks from the pools is described. This is the second outbreak of Legionella pneumophila linked to operating display spa pools in New Zealand and it appears to be the fourth recorded outbreak of Legionnaires' disease associated with operating spa pools on display.

[Pathogenesis, diagnosis and therapy of Legionella infections]. / Pathogenese, Diagnostik und Therapie der Legionella-Infektion.

Legionella species are ubiquitous in aquatic environments. About 50 years ago they entered the engineered (technical) environment, i.e. warm water systems with zones of stagnation. Since that time they represent a hygienic problem. After transmission to humans via aerosols legionellae might cause Legionella pneumonia (legionnaires' disease) or influenza-like respiratory infections (Pontiac fever). Epidemiological data suggest that Legionella strains might differ substantially in their virulence properties. Although the molecular basis is not understood L. pneumophila serogroup 1 especially MAb 3/1-positive strains cause the majority of infections. The main virulence feature is the ability to multiply intracellularly. After uptake into macrophages legionellae multiply in a specialized vacuole and finally lyse their host cells. Several bacterial factors like surface components, secretion systems and iron uptake systems are involved in this process. Since the clinical picture of Legionella pneumonia does not allow differentiation from pneumoniae caused by other pathogens, microbiological diagnostic methods are needed to establish the diagnosis. Cultivation of legionellae from clinical specimens, detection of antigens and DNA in patients' samples and detection of antibodies in serum samples are suitable methods. However, none of the diagnostic tests presently available offers the desired quality with respect to sensitivity and specificity. Therefore, the standard technique is to use several diagnostic tests in parallel. Advantages and disadvantages of the diagnostic procedures are discussed. Therapeutic options for Legionella infections are newer macrolides like azithromycin and chinolones (ciprofloxacin, levofloxacin and moxifloxacin).

Outbreak of Legionnaires' disease on a cruise ship linked to spa-bath filter stones contaminated with Legionella pneumophila serogroup 5.

In January 2003, two cases of Legionnaires' disease associated with a ship's cruise were registered in the database of National Epidemiological Surveillance of Infectious Diseases. A 70-year-old male heavy smoker with mild emphysema contracted the disease during a cruise. Legionella pneumophila serogroup (sg) 5 was isolated from the patient's sputum and the ship's indoor spa. The isolate from the spa matched the patient's isolate by genotyping performed by pulsed-field gel electrophoresis (PFGE). The second case was in a 73-year-old female. During epidemiological investigation, a third case of Legionnaire's disease in a 71-year-old male was subsequently diagnosed among passengers on the same ship on the following cruise. Environmental investigation revealed that porous natural stones (Maifanshi) in the filters of the spas had harboured L. pneumophila, a phenomenon which has not been reported except in Japan. This is the first documented evidence of L. pneumophila sg 5 infection on a ship and of porous stones as a source of Legionella infection.

[Legionella pneumonia which occurred in a private whirlpool bath user].

A 88 year old female with active rheumatoid arthritis treated by low dose of prednisolone and methotrexate was admitted to our hospital because of severe bilateral pulmonary infiltration and acute respiratory distress syndrome. On admission, she had consciousness disturbance and was intubated because of severe respiratory failure. We heard from her family of her habit she had taking a private whirlpool bath 2 or 3 times everyday. So, we suspected a Legionella pneumophila infection. We started intravenous erythromycin (EM) (1,500mg/day) and methylprednisolone pulse therapy (1,000mg x 3days) and full controlled mechanical ventilation supported with PEEP. Her respiratory failure was gradually improved and she was discharged on the 44 the hospital day. Legionella pneumophila (serogroup 6) was isolated in her sputum by B-CYE alpha culture. Legionella pneumophila (serogroup 6) was isolated in her private whirlpool bath too. Both samples revealed the same by genetic analysis with pulse field gel electrophoresis (PFGE). This is the first adult case of Legionella pneumophila pneumonia infected from a private whirlpool bath confirmed by genetic analysis. We should always suspect Legionella pneumonia as one of the severe community-acquired pneumonia, because Legionella pneumophila were frequently detected among various water sources including the private whirlpool bath.

Neonatal sudden death due to Legionella pneumonia associated with water birth in a domestic spa bath.

We report the first case of neonatal Legionnaires' disease associated with water birth in a spa bath at home. Legionella pneumophila serogroup 6 was detected from postmortem lung tissue.

[Occurrence of Legionella bacteria in a variety of environmental waters--from April, 1996 to November, 2000].

The present paper deals with the occurrence of Legionella bacteria in a variety of man-made environmental waters, including whirlpool bathes, cooling towers and others, from April 1996 to November 2000 in the eastern part of Japan around Tokyo area. A total of 2,895 water samples were examined for the possible occurrence of Legionella, and 904 (31%) were demonstrated to be positive. Among the various water sources, Legionella were frequently detected both in whirlpool bathes and in cooling towers, of which detection rates were 48% and 46%, respectively. More precisely, occurrence of Legionella was higher in private-use whirlpool bathes than those for public-use; namely, the positive rate was 71% in bathes accommodated in private houses, 63% in company's club houses, 62% in company dormitories for employees, and 51% in old-people's homes. Occurrence of Legionella, on the other hand, was less common (< or = 30%) in bathes for public-use such as those installed in hotels and in hot spring facilities. Typing of L. pneumophila serogroups revealed that SG5 (34%) was dominant in whirlpool bath waters followed by SG3 (22%), whereas SG1 (32%) was dominantly found in cooling tower waters.