[Evaluation of a Legionella outbreak emerged in a recently opening hotel].
[legionellosis]
Legionnaires' disease (LD) is a systemic infection caused by Legionella species especially colonized in the water systems. Hotels are common locations in which waterwork-associated sporadic or epidemic legionellosis can be detected. The aim of this study was to evaluate a small Legionella outbreak emerged in a recently opened 600-bed hotel in Alanya, a touristic county in Mediterranean part of Turkey. A 66 years old male patient who stayed in this hotel opened on May 15th, 2009, was admitted to our hospital on May 21st, 2009 with the complaints of high fever, headache and diarrhea lasting for three days. Since chest X-ray revealed non-homogenous density increase in left middle and inferior zone, the patient was diagnosed as atypical pneumoniae and LD was confirmed by positive urinary Legionella antigen test (Card test, BinaxNOW®Legionella Urinary Antigen Test; Alere Co, USA) result. Following the identification of the index case, the records of our hospital were reviewed and revealed another case being treated with the diagnosis of community acquired pneumonia who was also the guest of the same hotel. This patient was then diagnosed as LD by positive urinary antigen test. Since new cases were identified during the following days (May 22, 25 and 26) the Antalya County Health Department and hotel management were informed about a cluster of LD. In addition subsequent investigation for environmental surveillance and water sampling were conducted. The LD diagnosis and environmental inspections were performed according to the procedure described in the guideline from "Turkish Ministry of Health Travel-Associated Legionnaires' Disease Control Programme". Five definitive cases and one presumptive case of LD were identified during the outbreak period (May 20-26, 2009). All of the cases were successfully treated (intravenous ciprofloxacin or levofloxacin or clarithromycin), however one patient died due to sudden death during sleep after being discharged. Since sputum samples could not be obtained from the cases, the diagnosis were not confirmed by culture but by urinary antigen test. Besides high antibody titer in single serum sample was accepted as a diagnostic marker. Additionally 26 cases who accommodated in the same hotel and presented with high fever without pneumonia were treated in the outpatient clinics of our hospital. Urinary antigen test was performed in 11 of those patients to confirm the prediagnosis of pontiac fever, however all were found negative. Likewise convalescent phase sera for the confirmation of the diagnosis by seroconversion could not be obtained since they all were foreign tourists. Investigation of water sources of the hotel revealed that the municipal drinking water network had not been connected yet and the hotel supplied water from groundwater sources. The analysis of multiple samples from multiple sites of hotel's water system indicated that the water temperature was between 35-45°C and the iron level was beyond the acceptable limits (245 µg/L) recommended for drinking water in the regulation guides. These properties were considered as the factors that enhanced the growth and survival of Legionella species. Water samples were cultivated on BCYE-_ (Buffered Charcoal Yeast Extract a-Ketoglutarate) and GVPC (Glycine-Vancomycin-Polymyxin-Cycloheximide) agar plates and 11 out of a total 13 samples yielded Legionella spp. growth. All isolates were identified as L.pneumophila serogroup 1 by specific antisera. Legionella decontamination of hotel's water system was managed by implementation of hyperchlorination method as well as superheating (> 60°C) of water. The hotel was not closed during the outbreak and cultures of water samples obtained for one year later did not yield any Legionella spp. growth. This outbreak emphasized that hotel residents are at risk for acquiring LD in the presence of a colonized water system, even in a newly constructed building. In conclusion, effective control and decontamination programmes for the prevention of Legionella colonization should be applied even in new opening hotels.
