Legionella oakridgensis: laboratory diagnosis of a human infection

Aims: To investigate the prevalence of culturable and nonculturable Legionella species in hot water systems of public buildings in Japan and assess the risk factors associated with Legionella contamination in hot water systems. Methods and Results: Legionella species were detected by conventional culture and molecular methods in 130 water samples collected from 40 buildings. A total of 26 (20·0%) water samples from 17 (42·5%) buildings were positive by culture, qualitative PCR or both methods: Legionella pneumophila and Leg. anisa were detected in four samples by a culture method, whereas 23 samples were positive by qualitative PCR, with the presence of various Legionella species confirmed by sequencing. Of these 23 samples, bacterial counts were quantifiable in 21 by real‐time PCR (from 1·7 × 105 to 2·6 × 1011 cells per litre). Phylogenetic analysis of amplified partial 16S rRNA gene showed close relations to various species of Legionella, including Leg. anisa and Leg. micdadei, all of which have been associated with respiratory diseases or increased antibody titres in human sera. Assessment of risk factors showed that turbidity, free chlorine concentration, iron concentration and heterotrophic plate count (HPC) were significantly associated with Legionella contamination (P < 0·05). Conclusions: Contamination of hot water systems of public buildings with culturable and nonculturable Legionella species may be a potential risk factor for Legionella infection in Japan. Adequate levels of chlorine, low levels of iron and HPC are important maintenance measures in the reduction of Legionella contamination in hot water systems. Significance and Impact of the Study: More than 40% of hot water systems in the Japanese public buildings examined were contaminated by not only culturable Leg. pneumophila and Leg. anisa but also by nonculturable pathogenic species. To our knowledge, this is the first report of both culturable and nonculturable Legionella contamination in hot water systems of public buildings in Japan.

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“…lansingensis . These four species are also recognized as etiologic agents of Legionella infections (Tang et al. 1985; Wilkinson et al.…”

Section: Discussionmentioning

confidence: 99%

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Edagawa

Kimura

Doi

et al. 2008

Journal of Applied Microbiology

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“…Both patients had a previous history of immunological disorders treated with steroids (idiopathic thrombocytopenic purpura and rheumatoid arthritis, respectively), possibly rendering them more susceptible to infection. Pleural effusion was also present in the three previously reported cases of human L. oakridgensis infection (4,10,11), suggesting that this species might produce specific virulence factors (adhesins and/or extracellular products) favoring tropism for pleural tissue.…”

mentioning

confidence: 72%

“…L. oakridgensis was originally isolated from water in the environment (7,13) and was subsequently found to be responsible for several human cases of pleurisy (4,10,11). However, these human infections were diagnosed by DFA on clinical specimens and were not confirmed by culture of the organism (4, 10, 11).…”

mentioning

confidence: 99%

Isolation of Legionella oakridgensis from Two Patients with Pleural Effusion Living in the Same Geographical Area

et al. 2000

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“…L. pneumophila, L. micdadei, L. sainhelense, L. bozemanii, and L. oakridgensis are the species of legionellae most frequently associated with HCA-LD. [11][12][13] In a review article in 2000, Yu 11 indicated that in an 18-month period there had been eight outbreaks of nosocomial LD and that cases were reported from long-term care facilities (LTCFs), rehabilitation centers, and pediatric hospitals as well as acute care hospitals. He indicated that contamination of the institutional water supply was consistently linked to these cases and that the role of contaminated cooling towers as a vector for LD was controversial, with only two such outbreaks since 1982, one of which was subsequently shown to be due to contaminated potable water.…”

Section: Biology and Reservoirs Of Legionella Speciesmentioning

confidence: 99%

Healthcare-Associated Atypical Pneumonia

Forgie

Marrie

2009

Semin Respir Crit Care Med

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Atypical pneumonia was first described in 1938, and over time, Mycoplasma, Legionella, and Chlamydophila were the agents commonly linked with community-associated atypical pneumonia. However, as technology has improved, so has our understanding of this clinical entity. It is now known that there are many agents linked with atypical pneumonia in the community, and many of these agents are also major causes of healthcare-associated pneumonia. This article discusses the history, epidemiology, and pathogenesis of infection; control of infection; clinical findings; diagnosis; and, where applicable, treatment of the agents of healthcare-associated atypical pneumonia. Bacterial agents include Legionella species, Mycoplasma pneumoniae, Chlamydophila species, and Coxiella burnetii. Although there are over 100 viruses that can cause respiratory tract infections, only a fraction of those have been defined in the context of healthcare-associated atypical pneumonia: adenovirus and human bocavirus (HBoV); rhinovirus; human coronaviruses (HCoV), including HCoV 229E, HCoV OC43, HCoV NL63, HCoV HKU1; members of the paramyxoviridae (parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus); hantavirus; influenza; and severe acute respiratory syndrome (SARS) Co-V. Our knowledge about healthcare-associated atypical pneumonia will continue to evolve as newer pathogens are identified and as newer diagnostic modalities such as multiplex polymerase chain reaction are introduced.

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Legionella oakridgensis: laboratory diagnosis of a human infection

Abstract: We report the laboratory diagnosis of a case of pneumonia caused by Legionella oakridgensis. L. oakidgensis, originally isolated from industrial cooling towers, has not previously been associated with human disease.

Cited by 19 publications

References 5 publications

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Detection of culturable and nonculturableLegionellaspecies from hot water systems of public buildings in Japan

Isolation of Legionella oakridgensis from Two Patients with Pleural Effusion Living in the Same Geographical Area

Healthcare-Associated Atypical Pneumonia

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