Pneumophila Serogroup Research Articles

Starved viable but non-culturable (VBNC) Legionella strains can infect and replicate in amoebae and human macrophages

Legionella infections are among the most important waterborne infections with constantly increasing numbers of cases in industrialized countries, as a result of aging populations, rising numbers of immunocompromised individuals and increased need for conditioned water due to climate change. Surveillance of water systems is based on microbiological culture-based techniques; however, it has been shown that high percentages of the Legionella populations in water systems are not culturable. In the past two decades, the relevance of such viable but non-culturable (VBNC) legionellae has been controversially discussed, and whether VBNC legionellae can directly infect human macrophages, the primary targets of Legionella infections, remains unclear. In this study, it was demonstrated for the first time that several starved VBNC Legionella strains (four L. pneumophila serogroup 1 strains, a serogroup 6 strain and a L. micdadei strain) can directly infect different types of human macrophages and amoebae even after one year of starvation in ultrapure water. However, under these conditions, the strains caused infection with reduced efficacy, as represented by the lower percentages of infected cells, prolonged time in co-culture and higher multiplicities of infection required. Interestingly, the VBNC cells remained mostly non-culturable even after multiplication within the host cells. Amoebal infection by starved VBNC Legionella, which likely occurs in oligotrophic biofilms, would result in an increase in the bacterial concentration in drinking-water systems. If cells remain in the VBNC state, the real number of active legionellae will be underestimated by the use of culture-based standard techniques. Thus, further quantitative research is needed in order to determine, whether and how many starved VBNC Legionella cells are able to cause disease in humans.

Outbreak of Legionnaires' disease associated with cooling towers at a California state prison, 2015.

A large outbreak of Legionnaires' disease occurred at a California state prison in August 2015. We conducted environmental and epidemiological investigations to identify the most likely source of exposure and characterise morbidity. Sixty-four inmates had probable Legionnaires' disease; 14 had laboratory-confirmed legionellosis. Thirteen (17%) inmates were hospitalised; there were no deaths. Ill inmates were more likely to be ⩾65 years old (P < 0.01), have the chronic obstructive pulmonary disease (P < 0.01), diabetes mellitus (P = 0.02), hepatitis C infection (P < 0.01), or end-stage liver disease (P < 0.01). The case-patients were in ten housing units throughout the prison grounds. All either resided in or were near the central clinical building (for appointments or yard time) during their incubation periods. Legionella pneumophila serogroup 1 was cultured from three cooling towers on top of the central medical clinic (range, 880-1200 cfu/ml). An inadequate water management program, dense biofilm within the cooling towers, and high ambient temperatures preceding the outbreak created an ideal environment for Legionella sp. proliferation. All state prisons were directed to develop local operating procedures for maintaining their cooling towers and the state health department added a review of the maintenance plans to their environmental inspection protocol.

Adhesion of Legionella pneumophila on glass and plumbing materials commonly used in domestic water systems

ABSTRACTWe aimed to investigate the adhesion of Legionella pneumophila serogroup1 and L. pneumophila serogroup2–15 on glass, galvanized steel, stainless steel, copper, Polyvinyl chloride(PVC), Cross-linked polyethylene(PEX-c) and Polypropylene Random Copolymer(PPR). The surface physicochemical properties of both bacterial cells and materials were estimated through contact angle measurements. The roughness and surface topography of the materials were evaluated by Atomic Force Microscopy. The two L. pneumophila serogroups and plumbing materials showed a hydrophobic character, while glass surface was hydrophilic. All strains were adhered to all materials with the exception of copper. The result showed that the adhesion of both L. pneumophila sg1 and sg2–15 was systematically expressed with high intensity on galvanized steel followed by PVC, PEX-c, PPR, stainless steel and the low intensity on glass. The extent of adhesion is in correlation with the surface roughness and acid–bases interactions, while hydrophobicity seems to have no effect in adhesion intensity.

Effect of temperature and plumbing materials on biofilm formation by Legionella pneumophila serogroup 1 and 2-15

The purpose of our study was to investigate the biofilm formation by Legionella pneumophila serogroup1 and serogroup2-15 on plumbing materials mostly used in building water systems in Morocco. The effect of plumbing materials and temperature were examined. The Atomic Force Microscopy was used to evaluate the roughness and surface topography of the plumbing materials including galvanized steel, stainless steel, copper, Polyvinyl chloride, Polypropylene Random Copolymer and Cross-linked polyethylene. Galvanized steel surfaces supported higher numbers of bacterial cells than that the stainless steel and plastic materials at 37 than 20 and 45 °C. Non-viable counts could be obtained from the copper surfaces. L. pneumophila sg2-15 strains presented a higher ability to biofilm formation than L. pneumophila sg1. The biofilm formation was evaluated by Atomic Force Microscopy.

Investigation of Heterotrophic Bacteria, Legionella and Free - Living amoeba in Cooling Tower Samples by FISH and Culture Methods

The microorganisms living in the cooling towers water can affect both human health through inhalation of aerosolized water as well as industrial processes. In order to analyse such man-made water systems, microbiological tests that can give results in a short time are needed. In this study, the presence of heterotrophic bacteria, Legionella bacteria and free - living amoeba, FLA, including Acanthamoeba, in cooling-tower water and biofilm samples were investigated using two different methods, fluorescent in situ hybridization (FISH), and culture. For this, a total of 40 water and biofilm samples were taken from 16 different cooling towers in Istanbul. FISH and culture analysis have revealed that the number of heterotrophic bacteria within the water and the biofilm samples was above the threshold values (>105 cell. mL-1), generally. Despite Acanthamoeba were present in all cooling tower specimens, Legionella pneumophila serogroup 1 were only detected in the biofilm of one cooling tower. According to the results of this study, both methods are recommended to be used in conjunction. Due to the the large biodiversity of FLA such as Hartmanella sp. and Naeglaria sp, there is a need for new studies utilizing FISH method for sensitive, reliable results in a short period of time.

Distribution of Legionella and bacterial community composition among regionally diverse US cooling towers.

Cooling towers (CTs) are a leading source of outbreaks of Legionnaires’ disease (LD), a severe form of pneumonia caused by inhalation of aerosols containing Legionella bacteria. Accordingly, proper maintenance of CTs is vital for the prevention of LD. The aim of this study was to determine the distribution of Legionella in a subset of regionally diverse US CTs and characterize the associated microbial communities. Between July and September of 2016, we obtained aliquots from water samples collected for routine Legionella testing from 196 CTs located in eight of the nine continental US climate regions. After screening for Legionella by PCR, positive samples were cultured and the resulting Legionella isolates were further characterized. Overall, 84% (164) were PCR-positive, including samples from every region studied. Of the PCR-positive samples, Legionella spp were isolated from 47% (78), L. pneumophila was isolated from 32% (53), and L. pneumophila serogroup 1 (Lp1) was isolated from 24% (40). Overall, 144 unique Legionella isolates were identified; 53% (76) of these were Legionella pneumophila. Of the 76 L. pneumophila isolates, 51% (39) were Lp1. Legionella were isolated from CTs in seven of the eight US regions examined. 16S rRNA amplicon sequencing was used to compare the bacterial communities of CT waters with and without detectable Legionella as well as the microbiomes of waters from different climate regions. Interestingly, the microbial communities were homogenous across climate regions. When a subset of seven CTs sampled in April and July were compared, there was no association with changes in corresponding CT microbiomes over time in the samples that became culture-positive for Legionella. Legionella species and Lp1 were detected frequently among the samples examined in this first large-scale study of Legionella in US CTs. Our findings highlight that, under the right conditions, there is the potential for CT-related LD outbreaks to occur throughout the US.

Legionella pneumonia due to non-Legionella pneumophila serogroup 1: usefulness of the six-point scoring system

BackgroundBecause of a limited number of reports, we aimed to investigate the clinical characteristics of patients with Legionella pneumonia due to non-Legionella pneumophila serogroup 1 and the diagnostic usefulness of the six-point scoring system for such patients compared with patients with pneumonia caused by L. pneumophila serogroup 1.MethodsWe retrospectively analysed patients diagnosed with Legionella pneumonia due to non-L. pneumophila serogroup 1 between March 2001 and June 2016. We examined the clinical characteristics, including symptoms, laboratory findings, radiologic findings, pneumonia severity, initial treatment and prognosis. We also calculated scores using the six-point scoring system in these patients. Furthermore, we compared the clinical characteristics and six-point scores between non-L. pneumophila serogroup 1 patients and L. pneumophila serogroup 1 patients among hospitalized community-acquired pneumonia patients enrolled prospectively between October 2010 and July 2016.ResultsEleven patients had pneumonia due to non-L. pneumophila serogroup 1; their median age was 66 years and 8 patients (72.7%) were male. The most common pathogen was L. pneumophila serogroup 3 (6/11), followed by L. pneumophila serogroup 9 (3/11), L. pneumophila serogroup 6 (1/11) and L. longbeachae (1/11). Non-specific symptoms, such as fever and cough, were common. Six patients (54.5%) had liver enzyme elevation, but no patient developed hyponatraemia at <130 mEq/L. Nine patients (81.8%) showed lobar pneumonia and 7 patients (63.6%) manifested with consolidation and ground-glass opacity. Patients with mild to moderate severity comprised 10 (90.9%) by CURB-65 and 5 (45.5%) by the Pneumonia Severity Index. Of all patients, 4 were admitted to the intensive care unit and 3 died despite appropriate empiric therapy. The clinical characteristics were not significantly different between non-L. pneumophila serogroup 1 patients and L. pneumophila serogroup 1 patients (n = 23). At a cut-off value of ≥ 2 points, the sensitivity of the six-point scoring system was 54.5% (6/11) for non-L. pneumophila serogroup 1 patients and 95.7% (22/23) for L. pneumophila serogroup 1 patients.ConclusionsCases of non-L. pneumophila serogroup 1 pneumonia varied in severity from mild to severe and the clinical characteristics were often non-specific. The six-point scoring system was not useful in predicting such Legionella pneumonia cases.

Antibiotic susceptibility of clinical Legionella pneumophila serogroup 1 strains isolated in Germany.

Antibiotic susceptibility of clinical Legionella pneumophila serogroup 1 strains isolated in Germany.

A combined outbreak of Legionnaires’ disease and Pontiac fever related to an ultrasonic humidifier contaminated with Legionella pneumophila serogroup 1, Nanjing City, China, 2012

Background: On June 14, 2012, more than ten female workers from factory L were reported for illness with fever, chest tightness, myalgia, and non-productive cough within 1 day in Nanjing City, China. To verify and control the outbreak, we conducted this epidemiological investigation. Methods: A face to face interview was used for the case finding and information collecting, and conducted to the total of 45 staffs by a structured questionnaire. Urine samples from all cases were collected and tested for Legionella pneumophila serogroup 1 (LP1) antigen, and five sera samples were tested for Legionella antigen and Legionella antibody. Two cooling water samples from cabinet air conditioner and three from the humidifier were collected to test Legionella bacteria. The attack rate (AR) was calculated for overall and for different production lines, individually. Results: A total of 15 cases, 9 suspected cases and 6 confirmed cases, 8 Legionnaires’ disease (LD) cases and 7 Pontiac fever (PF) cases, 5 inpatients and 10 outpatients, with an overall AR of 75% (15/20, one worker was for personal leave) were identified for illness onset on June 13, 2012. Six of 15 cases urine samples were tested positive for LP1; 1 of 5 inpatients was positive for Legionella antibody and another for antigen positive. Legionella bacteria was isolated from one water sample from the humidifier and confirmed as LP1. Conclusions: A combined outbreak of LD and PF caused by a contaminated humidifier was demonstrated and it was the first report and in China.

A Unique Case of Legionella and Streptococcus Pneumoniae Coinfection

SESSION TITLE: Bacterial Infections 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Community-acquired pneumonia (CAP) is a frequent cause of hospitalization in adults. Most cases of CAP are caused by a single pathogen, with Streptococcus pneumoniae (pneumococcus) identified most commonly. Alternatively, Legionella pneumophilia is a less common cause of CAP. Although co-infections have been previously described, presence of both pneumococcus and legionella together in CAP is rare. We present a patient with positive urinary antigens for both pneumococcus and Legionella pneumophilia serogroup 1 (Lp1), indicating an unusual co-infection. CASE PRESENTATION: An 80 year old female presented with fatigue, weakness and progressively worsening shortness of breath. She was noted to be tachypneic and hypoxic on room air. Blood work was significant for neutrophil-predominant leukocytosis, however, initial serum procalcitonin concentration was low and chest X-ray was only significant for hyper-inflated lungs. She was admitted for treatment of presumed COPD exacerbation but her respiratory status progressively worsened requiring non-invasive ventilatory support. Repeat serum procalcitonin was significantly elevated. Computed tomography (CT) scan of the chest without contrast was significant for bilateral lower lobes tree-in-bud opacities. Sputum cultures, blood cultures and streptococcus pneumonia and legionella pneumophilia urinary antigens were obtained and she was started on broad spectrum antibiotics. Blood cultures remained negative but surprisingly urinary antigens for both pneumococcus and Lp1 returned positive. Antibiotics were then de-escalated to levofloxacin. The patient’s clinical status improved and she was discharged home in stable condition after a one week hospital course. DISCUSSION: Although co-infections with S. pneumoniae and L. pneumophilia have been described, this appears to be only the second case where a co-infection for CAP was diagnosed on the basis of positive urinary antigens. Various studies have shown high specificity and positive predictive value of urinary antigens and, therefore, such tests should be used as diagnostic tools to identify causative organisms of pneumonia. CONCLUSIONS: This unique case of pneumococcus and Legionella co-infection demonstrates the importance of urinary antigens in patients hospitalized secondary to CAP in addition to sputum cultures and peripheral blood cultures. This approach will promote early institution of organism specific antibiotic therapy and foster antibiotic stewardship. Reference #1: Lionel A. Mandell, Richard G. Wunderink, Antonio Anzueto, John G. Bartlett, G. Douglas Campbell, Nathan C. Dean, Scott F. Dowell, Thomas M. File, Jr., Daniel M. Musher, Michael S. Niederman, Antonio Torres, Cynthia G. Whitney; Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia in Adults. Clin Infect Dis 2007; 44 (Supplement_2): S27-S72. doi: 10.1086/511159 DISCLOSURE: The following authors have nothing to disclose: Moeezullah Beg, Sara Loucks, Hamza Arif, Tiffany Dumont No Product/Research Disclosure Information

Healthcare-associated Legionnaires' disease: Limitations of surveillance definitions and importance of epidemiologic investigation.

Healthcare-associated Legionnaires' disease (HCA LD) causes significant morbidity and mortality, with varying guidance on prevention. We describe the evaluation of a case of possible HCA LD and note the pitfalls of relying solely on an epidemiologic definition for association of a case with a facility. Our detailed investigation led to the identification of a new Legionella pneumophila serogroup 1 sequence type, confirmed a healthcare association and helped build the framework for our ongoing preventive efforts. Our experience highlights the role of routine environmental cultures in the assessment of risk for a given facility. As clinicians increasingly rely on urinary antigen testing for the detection of L. pneumophila, our investigation emphasises the importance of clinical cultures in an epidemiologic investigation.

Community-acquired Legionnaires’ Disease in a Newly Constructed Apartment Building

ObjectivesLegionnaires’ disease (LD) is a severe type of pneumonia caused by inhalation of aerosols contaminated with Legionella. On September 22, 2016, a single case of LD was reported from a newly built apartment building in Gyeonggi province. This article describes an epidemiologic investigation of LD and identification of the possible source of infection.MethodsTo identify the source of LD, we interviewed the patient’s husband using a questionnaire based on the Legionella management guidelines from the Korea Centers for Disease Control and Prevention. Water samples from the site were collected and analyzed. An epidemiological investigation of the residents and visitors in the apartment building was conducted for 14 days before the index patient’s symptoms first appeared to 14 days after the implementation of environmental control measures.ResultsLegionella pneumophila serogroup 1 was isolated from the heated-water samples from the patient’s residence and the basement of the apartment complex. Thirty-two suspected cases were reported from the apartment building during the surveillance period, yet all were confirmed negative based on urinary antigen tests.ConclusionsThe likely source of infection was the building’s potable water, particularly heated water. Further study of effective monitoring systems in heated potable water should be considered.

Incubation of premise plumbing water samples on Buffered Charcoal Yeast Extract agar at elevated temperature and pH selects for Legionella pneumophila

Worldwide, over 90% of the notified cases of Legionnaires' disease are caused by Legionella pneumophila. However, the standard culture medium for the detection of Legionella in environmental water samples, Buffered Charcoal Yeast Extract (BCYE) agar of pH 6.9 ± 0.4 with or without antimicrobial agents incubated at 36 ± 1 °C, supports the growth of a large diversity of Legionella species. BCYE agar of elevated pH or/and incubation at elevated temperature gave strongly reduced recoveries of most of 26 L. non-pneumophila spp. tested, but not of L. pneumophila. BCYE agar of pH 7.3 ± 0.1, incubated at 40 ± 0.5 °C (BCYE pH 7.3/40 °C) was tested for selective enumeration of L. pneumophila. Of the L. non-pneumophila spp. tested, only L. adelaidensis and L. londiniensis multiplied under these conditions. The colony counts on BCYE pH 7.3/40 °C of a L. pneumophila serogroup 1 strain cultured in tap water did not differ significantly from those on BCYE pH 6.9/36 °C when directly plated and after membrane filtration and showed repeatability's of 13–14%. By using membrane filtration L. pneumophila was detected in 58 (54%) of 107 Legionella-positive water samples from premise plumbing systems under one or both of these culture conditions. The L. pneumophila colony counts (log-transformed) on BCYE pH 7.3/40 °C were strongly related (r2 = 0.87) to those on BCYE pH 6.9/36 °C, but differed significantly (p < 0.05) by a mean of – 0.12 ± 0.30 logs. L. non-pneumophila spp. were detected only on BCYE pH 6.9/36 °C in 49 (46%) of the samples. Hence, BCYE pH 7.3/40 °C can facilitate the enumeration of L. pneumophila and their isolation from premise plumbing systems with culturable L. non-pneumophila spp., some of which, e.g. L. anisa, can be present in high numbers.

Genomic investigation of a suspected outbreak of Legionella pneumophila ST82 reveals undetected heterogeneity by the present gold-standard methods, Denmark, July to November 2014.

Between July and November 2014, 15 community-acquired cases of Legionnaires´ disease (LD), including four with Legionella pneumophila serogroup 1 sequence type (ST) 82, were diagnosed in Northern Zealand, Denmark. An outbreak was suspected. No ST82 isolates were found in environmental samples and no external source was established. Four putative-outbreak ST82 isolates were retrospectively subjected to whole genome sequencing (WGS) followed by phylogenetic analyses with epidemiologically unrelated ST82 sequences. The four putative-outbreak ST82 sequences fell into two clades, the two clades were separated by ca 1,700 single nt polymorphisms (SNP)s when recombination regions were included but only by 12 to 21 SNPs when these were removed. A single putative-outbreak ST82 isolate sequence segregated in the first clade. The other three clustered in the second clade, where all included sequences had < 5 SNP differences between them. Intriguingly, this clade also comprised epidemiologically unrelated isolate sequences from the UK and Denmark dating back as early as 2011. The study confirms that recombination plays a major role in L. pneumophila evolution. On the other hand, strains belonging to the same ST can have only few SNP differences despite being sampled over both large timespans and geographic distances. These are two important factors to consider in outbreak investigations.

The 2015 New York City Legionnaires' Disease Outbreak: A Case Study on a History-Making Outbreak.

The 2015 New York City Legionnaires' Disease Outbreak: A Case Study on a History-Making Outbreak.

Evaluation of the bioNexia Legionella Test, Including Impact of Incubation Time Extension, for Detection of Legionella pneumophila Serogroup 1 Antigen in Urine

In this study, we compared the bioNexia test (bioMérieux, Marcy-l'Étoile, France), a new immunochromatographic assay for the detection of Legionella pneumophila serogroup 1 in urine, with the BinaxNOW urinary antigen test (Alere, Waltham, Massachusetts, USA). After 15 min of incubation (in accordance with the manufacturers' instructions), the sensitivities and specificities were, respectively, 76.5% and 97.2% for the bioNexia test and 87.1% and 100% for the BinaxNOW test. After a prolonged incubation time of 60 min, the sensitivities and specificities increased to, respectively, 89.4% and 97.2% for the bioNexia test and 91.8% and 100% for the BinaxNOW test. When the tests were read after 15 min, the concentration of discrepant urine samples increased the sensitivities to 94.1% for both tests. In conclusion, we found that although the bioNexia test showed lower sensitivity for the detection of L. pneumophila antigen in nonconcentrated urine compared to the BinaxNOW test, a prolonged incubation time as well as the use of concentrated samples showed comparable sensitivities for both tests.

Aetiological ahents of Adult Bacterial Pneumonia parients admitted at a Tertiary Care Hospital in Dhaka city

Background: Bacterial pneumonia is one of the most common causes of mortality and morbidity worldwide especially in adults.Objective: The purpose of this present study was to identify the aetiological agents and antimicrobial sensitivity pattern of bacterial pneumonia in patients admitted at intensive care unit (ICU).Methodology: This cross sectional study was carried out in the Department of Microbiology &amp; Immunology at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from August 2012 to July 2013. Blood and tracheal aspirates (TA) culture were done in clinically diagnosed pneumonia patients admitted in the ICU of BSMMU. PCR of TA was performed to identify Legionella species. Urine ICT of patients was done to detect Streptococcus pneumoniae and Legionella pneumophila serogroup 1 antigens. Antimicrobial susceptibility of isolated bacteria was done by disc diffusion method.Result: A total of 36 pneumonia patients admitted at ICU were recruited. The most common identified bacteria were Acinetobacter species (33.3%) followed by Pseudomonas species (30.5%), Klebsiella pneumoniae (11.1%), Escherichia coli (5.5%), Enterobacter aerogenes (5.5%), Legionella (8.3%), Citrobacterfreundii (2.8%) and Proteus mirabilis (2.8%). Majority of the bacteria were resistant to first line antibiotics and highly sensitive to carbapenems.Conclusion: Most common isolated bacteria are the Acinetobacter species, Pseudomonas species and Klebsiella pneumoniae among the pneumonic patients with the resistant to first line antibiotics and sensitive to carbapenems.J Shaheed Suhrawardy Med Coll, 2015; 7(1):22-25

The typical presentation of an atypical pathogen during an outbreak of Legionnaires’ disease in Vila Franca de Xira, Portugal, 2014

BackgroundAn outbreak of Legionella pneumophila serogroup 1, with 403 cases was identified on the 7th November 2014 in Vila Franca de Xira, Portugal. Outbreak source was the wet cooling system of a local factory. Hospital Pulido Valente was one of the hospitals receiving patients with Legionnaires’ disease (LD). MethodsWe describe the clinical findings and diagnostic methods used among the 43 confirmed or probable cases admitted to our department. Results60.5% were male, mean age was 56.1±13.5 years and tobacco smoking was the most frequent risk factor (76.7%). All patients had fever, 62.8% ≥39.5°C, 72.1% had chills and myalgia/arthralgia and 62.8% had dry cough. Extra pulmonary symptoms were frequent: confusion and headache occurred in 34.9% and gastrointestinal symptoms in 20.9%.High C-Reactive Protein (55.8% ≥30mg/dL) and hyponatremia (62.8%) were the laboratorial abnormalities most commonly found. Hypoxemia occurred in 55.8% and hypocapnia in 93%. Urinary Antigen Test (UAT) was positive in 83.7% of the cases. ConclusionsAlthough not specific, a combination of risk factors, symptoms and laboratory findings can be highly suggestive of LD, even in an outbreak. This should prompt diagnosis confirmation. Routine use of UAT in less severe cases of community acquired pneumonia might contribute to earlier diagnosis.

Rapid diagnostic test for respiratory infections

Acute respiratory infections are the second cause of morbidity and mortality in children and adults worldwide, being viruses, bacteria and fungi involved in their aetiology. The rapid diagnosis allows for a better clinical management of the patient, for adopting public health measures and for controlling possible outbreaks. The main etiologic agents can be diagnosed within the first hours after the onset of symptoms with antigen detection techniques, primarily immunochromatography. Results are obtained in 15–30min, with 70–90% sensitivity and >95% specificity for the diagnosis of Streptococcus pneumoniae and Legionella pneumophila serogroup O1 infections from urine, Streptococcus pyogenes from throat swabs and respiratory syncytial virus from nasopharyngeal aspirates. Worse results are obtained for influenza viruses and Pneumocystis jirovecii with these techniques; however, other easy-to-perform molecular techniques are available for the rapid diagnosis of these microorganisms. In general, these techniques should not be used for monitoring the outcome or response to treatment.

Legionellosis acquired through a dental unit: a case study

In 2012, an elderly immunocompromised man died from legionellosis at a hospital in Uppsala, Sweden. The patient had visited a dental ward at the hospital during the incubation period. Legionella spp. at a concentration of 2000 colony-forming units/L were isolated from the cupfiller outlet providing water for oral rinsing. Isolates from the patient and the dental unit were Legionella pneumophila serogroup 1, subgroup Knoxville and ST9. Pulsed-field gel electrophoresis and whole-genome sequencing strongly suggested that the isolates were of common origin. This report presents one of few documented cases of legionellosis acquired through a dental unit.