LEGIONELLA - World Health Organization

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Ideally, specimens for culture should be taken before antibiotic treatment is initiated, although Legionella has been isolated from lower respiratory tract specimens and blood after several days treatment with erythromycin. Sputum should be considered for culture even when not purulent (Ingram & Plouffe, 1994). Respiratory specimens that are particularly difficult to obtain, such as lung tissue, pleural fluid or bronchoalveolar lavage (BAL), should be cultured if received on a routine basis (Stout, Rihs & Yu, 2003). Legionella has been successfully isolated from lower respiratory tract specimens, including BAL, transtracheal aspirate, endotracheal suction specimens, pleural fluid, lung biopsy and expectorated sputum. In the early phase of illness, legionellosis is often accompanied by a dry cough with little sputum. In this context, the low number of organisms present outside the lungs and the inhibitory effect of oral flora reduce the sensitivity of the culture method. In severe forms of legionellosis, especially in immunocompromised patients, bacteraemia (bacterial spread to the bloodstream) can occur, with a frequency of approximately 30% in patients with severe legionellosis. Sometimes, legionellae are found in samples from extrapulmonary sites, especially from postmortem specimens (e.g. liver, spleen, pericardial fluid, kidney wounds, cutaneous abscess or vascular grafts). Benefits and limitations of using culture media Culture of Legionella is often the most sensitive detection method, and has high specificity (>99%) (Edelstein, 1987). Culture is particularly important for diagnosis in: • cases in which severe pneumonia causes respiratory failure • immunocompromised patients • nosocomial infections • cases in which disease is caused by any legionellae other than L. pneumophila serogroup 1. Some legionellae cannot be grown on routine Legionella culture media and have been termed Legionella-like amoebal pathogens (LLAPs), because they grow in certain host species of amoeba. These organisms have been isolated and maintained in culture by co-cultivating the bacteria with their protozoan hosts. One LLAP strain was isolated from the sputum of a pneumonia patient by enrichment in amoebae. This LLAP strain is considered to be a human pathogen (Fry et al., 1999; Marrie et al., 2001). Other LLAP strains may be human pathogens, although this is difficult to prove because they cannot be detected by conventional techniques used for legionellae. Recently, three LLAP strains were named Legionella species (Adeleke et al., 2001; La Scola et al., 2004). 0 <strong>LEGIONELLA</strong> AND THE PREVENTION OF LEGIONELLOSIS
11.2.2 Detecting Legionella antigens Urinary antigens Enzyme immunoassays The use of enzyme immunoassays (EIAs) for detecting L. pneumophila antigen in urine allows Legionnaires’ disease to be diagnosed early in the course of infection. EIA is a convenient and rapid test with excellent specificity and sensitivity for L. pneumophila serogroup 1. The antigen is detectable in most patients between one and three days after the onset of symptoms, and may persist for some weeks or months — even when other tests can no longer detect the antigen (Birtles, 1990). The EIA urine antigen test has 80–85% specificity, which is similar to culture (Hackman et al., 1996; Kazandjian, Chiew & Gilbert, 1997), but may have greater sensitivity than culture. Commercial EIA kits are available for detecting L. pneumophila serogroup 1 antigen in urine. Immunoassay for detection of urinary antigen is the method of choice for L. pneumophila serogroup 1 (Cosentini et al., 2001; Formica et al., 2001). Compared with other diagnostic methods, the advantages of urinary antigen detection are striking. Specimens are easily obtained, the antigen is detectable very early in the course of disease, and the test is rapid and specific. The antigen might also be detectable in non-pneumonic illnesses and during antibiotic therapy (Lück, Helbig & Schuppler, 2002). Immunochromatographic assays A rapid immunochromatographic assay for detecting L. pneumophila serogroup 1 antigen in urine is also available. This assay detects urinary antigen within a very short time and does not require laboratory equipment (Helbig et al., 2001). Concentration of urine improves the sensitivity of both the EIA and immunochromatographic assays, without decreasing their specificity. Tissue antigens Indirect immunofluorescence microscopy Immunofluorescence microscopy can be used to detect Legionella, using either direct or indirect techniques, in samples such as respiratory tract secretions, lung and pleural fluid. The indirect immunofluorescence antibody technique (IFAT) is used in most laboratories to detect the serum antibody level. A fourfold rise in titre develops within 1–9 weeks after disease onset in approximately three quarters of patients with culture-proven legionellosis caused by L. pneumophila serogroup 1. On average, patients seroconvert (develop antibodies) within two weeks; however, up to 25% of seroconversions are undetected because serum is collected more than eight weeks after disease onset. <strong>LEGIONELLA</strong> AND THE PREVENTION OF LEGIONELLOSIS
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LEGIONELLA AND THE PREVENTION OF LE
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LEGIONELLA AND THE PREVENTION OF LE
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Foreword Legionellosis is a collect
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Contents Foreword . . . . . . . . .
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Chapter 5 Cooling towers and evapor
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Chapter 9 Disease surveillance and
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Tables Table 1.1 Main characteristi
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Figure 8.1 Visible biofilm on inter
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Acknowledgements The World Health O
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• John Newbold, Health and Safety
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Executive summary Legionellosis is
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• Health-care facilities — Chap
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Chapter 1 Legionellosis Britt Horne
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Legionnaires’ disease is often in
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1.1.2 Pontiac fever Symptoms Pontia
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Table . Extrapulmonary nfect ons ca
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Proteins produced by the body’s i
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Aspiration may occur in patients wi
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Table . R sk factors for Legionella
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In the outbreak of Legionnaires’
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Table . Potent al treatments for d
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1.4.2 Species and serogroups associ
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Other causes of infection In Europe
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The interaction of virulent legione
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1.5.2 Surface structures involved i
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1.5.4 Host defence The host defence
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Chapter 2 Ecology and environmental
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L. pneumophila is thermotolerant an
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2.2.3 Environmental factors and vir
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Figure 2.1 Biofilm formation Biofil
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2.4 Sources of Legionella infection
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Chapter 3 Approaches to risk manage
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Table . Cool ng tower outbreaks Fac
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Even when a source reaches a state
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The WSP should be prepared in conju
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Identify control measures Control m
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F gure . Dec mal reduct on t mes fo
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Method Advantages D sadvantages Dos
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Validate effectiveness of water saf
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• clear statements of responsibil
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Chapter 4 Potable water and in-buil
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The remainder of this chapter provi
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4.3.1 Document and describe the sys
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Construction materials — risk fac
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Where temperature controls (discuss
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4.4.2 Monitor control measures This
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Chapter 5 Cooling towers and evapor
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5.1.1 Cross-flow cooling towers As
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water treatments (including chemica
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5.3 System assessment This section
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Spray drift — risk factors Even w
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The section on control measures for
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• periodic or continuous bleed-of
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Box . Po nts to be noted when clean
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In certain circumstances, samples m
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Table . Example documentat on for m
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Chapter 6 Health-care facilities Ma
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For 1999 and 2000, a total of 384 c
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6.3 System assessment This section
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Table . Type of colon zat on of wat
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6.4.1 Identify control measures Thi
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6.5.1 Prepare management procedures
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Until the situation is under contro
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Chapter 7 Hotels and ships Roisin R
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F gure . Detected and reported case
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Table . Rev ew of outbreaks (more t
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7.2 Water safety plan overview WSPs
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The risk of legionellosis is increa
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Kingdom to 66% in Spain (Starlinger
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Agency, Legionella Section, United
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Given the complexity of distributio
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Chapter 8 Natural spas, hot tubs an
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Spas “Natural spa”, denotes fac
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Rare cases of Legionnaires’ disea
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Process step P pework Water n hot t
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Hosepipes may sometimes be used to
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Page 155 and 156: Nutrients — control measures Bath
Page 157 and 158: Various additives may also be used
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Page 161 and 162: Table . Examples of m crob olog cal
Page 163 and 164: Chapter 9 Disease surveillance and
Page 165 and 166: Exposure histories allow cases to b
Page 167 and 168: F gure . Invest gat ng a s ngle cas
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Page 171 and 172: Country United Kingdom All reported
Page 173 and 174: F gure . Annual reported cases, - 0
Page 175 and 176: Training opportunities Trainees in
Page 177 and 178: Box . Example of terms of reference
Page 179 and 180: ecause doing anything more could un
Page 181 and 182: 9.4 Case studies This section descr
Page 183 and 184: 9.4.4 Concrete batcher process on a
Page 185 and 186: Chapter 10 Regulatory aspects David
Page 187 and 188: • validation of the effectiveness
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Page 191 and 192: 10.4.6 Outbreak investigation and n
Page 193 and 194: hot water (e.g. health-care facilit
Page 195 and 196: General prevent on Country DW Wp SB
Page 197 and 198: Country General prevent on DW Wp SB
Page 199 and 200: Chapter 11 Laboratory aspects of Le
Page 201 and 202: • detection of the bacterium in t
Page 203: Method Sens t v ty (%) PCR • Rapi
Page 207 and 208: DFA has been used successfully with
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Page 213 and 214: Generally, any water source that ma
Page 215 and 216: During outbreak investigations, swa
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Page 219 and 220: Appendix 1 Example of a water syste
Page 221 and 222: Weekly water system check list Week
Page 223 and 224: Appendix 2 Example of a 2-week foll
Page 225 and 226: Travel Work/travel in the UK: ❑ Y
Page 227 and 228: Checklist of local places Health/sp
Page 229 and 230: Appendix 3 Example of a national su
Page 231 and 232: Strictly Confidential 2 Hospital Ac
Page 233 and 234: Glossary aerobic bacteria Bacteria
Page 235 and 236: health-care acquired Legionellosis
Page 237 and 238: surveillance The process of systema
Page 239 and 240: References Abu KY, Eisenstein BI, E
Page 241 and 242: Barbaree JM et al. (1987). Protocol
Page 243 and 244: Blatt SP et al. (1994). Legionnaire
Page 245 and 246: Byrne B, Swanson MS (1998). Express
Page 247 and 248: Crespi S (1993). Legionella y legio
Page 249 and 250: Edelstein PH (1982b). Comparative s
Page 251 and 252: Falguera M et al. (2001). Nonsevere
Page 253 and 254: Gaia V et al. (2003). Sequence-base
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Hayden RT et al. (2001). Direct det
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Ingram JG, Plouffe JF (1994). Dange
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Ko KS et al. (2003). Molecular evol
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Loret JF et al. (2003). Comparison
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McEvoy M et al. (2000). A cluster o
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Olaechea PM et al. (1996). A predic
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Regan CM et al. (2003). Outbreak of
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Schulze-Robbecke R, Rodder M, Exner
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Surman SB, Morton LHG, Keevil CW (1
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Tully M, Williams A, Fitzgeorge RB
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Welti M et al. (2003). Development
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