{"id":972,"date":"2020-02-18T11:51:02","date_gmt":"2020-02-18T11:51:02","guid":{"rendered":"https:\/\/www.aqualab.pt\/?post_type=mppost&#038;p=972"},"modified":"2021-03-09T13:07:47","modified_gmt":"2021-03-09T13:07:47","slug":"legionella-prevention-culture-method","status":"publish","type":"mppost","link":"https:\/\/aqualab.pt\/en\/pages\/treatment-suggestion\/legionella-prevention-culture-method\/","title":{"rendered":"Legionella Prevention \u2014 Culture Method"},"content":{"rendered":"\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n<noscript class=\"loading-lazy\">\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"427\" src=\"https:\/\/www.aqualab.pt\/files\/uploads\/2021\/03\/torneira-1024x427.jpg\" alt=\"\" class=\"wp-image-2849\" srcset=\"https:\/\/aqualab.pt\/files\/uploads\/2021\/03\/torneira-1024x427.jpg 1024w, https:\/\/aqualab.pt\/files\/uploads\/2021\/03\/torneira-300x125.jpg 300w, https:\/\/aqualab.pt\/files\/uploads\/2021\/03\/torneira-768x320.jpg 768w, https:\/\/aqualab.pt\/files\/uploads\/2021\/03\/torneira.jpg 1200w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n<\/noscript>\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong>\u201cThe bacteria of the Legionella genus are found in natural aquatic environments and in artificial systems, such as supply networks\/water distribution, building networks of hot and cold water, air conditioning and cooling systems (cooling towers, evaporative condensers and humidifiers) found in buildings, including hotels, spas, shopping centres and hospitals.<\/strong> <strong>They can also be found in ornamental fountains and recreational tanks, like hot tubs.&#8221;<\/strong><\/p>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n\n<p>Exposure to the bacteria can cause respiratory infection, currently known as Legionnaires&#8217; disease. It is important to distinguish the status of colonization of water systems by bacteria of the Legionella genus, from the occurrence of an event of Legionnaires&#8217; disease.<\/p>\n\n\n\n<p>There are no guide numbers for the concentration of the Legionella genus in water in colonies forming units per liter (cfu L), higher than what occurs Legionnaires&#8217; disease and lower than the probability of occurrence is almost zero.&#8221;<\/p>\n\n\n\n<p>In: Prevention and Control of Legionella in water systems, the Portuguese Quality Institute in partnership with EPAL, Empresa Portuguesa das \u00c1guas Livres, SA, 2nd Edition 2014.<\/p>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<figure class=\"wp-block-table alignwide is-style-stripes\"><table><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Legionella spp<\/strong><\/td><td class=\"has-text-align-center\" data-align=\"center\"><strong>Matrix<\/strong><\/td><td class=\"has-text-align-center\" data-align=\"center\"><strong>Unit<\/strong><\/td><td><strong>Reference Conditions<\/strong><\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Legionella spp<\/strong><\/td><td class=\"has-text-align-center\" data-align=\"center\">Water<\/td><td class=\"has-text-align-center\" data-align=\"center\">(cfu\/L)<\/td><td>Concentration of less than 100 cfu\/L, except in the case of research in cooling towers tanks, where must a lower concentration of 1000 cfu\/L. be registered.<br> Absence of Legionella pneumophila<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">Reference data and corrective actions in building networks<\/h3>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n\n<p>\u201cUsually, for building network water, it is considered that a Legionella analysis, from an operation and maintenance point of view, is unfavourable when the concentration of Legionella spp., is \u22651000 cfu\/L, which corresponds to an alert level, making it necessary to collect new samples, review the water treatment program, assess the risk and if necessary clean and disinfect the system or implement chemical shock treatments and\/or thermal, subsequently evaluating the effectiveness of the implemented measures.<\/p>\n\n\n\n<p>For amounts lower than 100 cfu\/L of Legionella spp., the system is considered to be under control. However, these values are not identical throughout the literature and should be only taken as a reference.<\/p>\n\n\n\n<p>Regarding respiratory therapy equipment, the limit number is 0 cfu\/L, because the risk is so great.&#8221;<\/p>\n\n\n\n<p>In: Prevention and Control of Legionella in water systems, the Portuguese Quality Institute in partnership with EPAL, Empresa Portuguesa das \u00c1guas Livres, SA, 2nd Edition 2014.<\/p>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">Chemical Disinfection<\/h3>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n\n<ul class=\"wp-block-list\"><li>Chlorinate the water in the cold water storage tank, adding sodium hypochlorite until you reach a level of residual free chlorine of 20 to 50 mg\/L; the next step is to re-circulate the chlorinated water in the entire system, successively opening all taps and showers until you detect an intense smell of chlorine;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Close all exits, putting the system on standby for approximately one hour to reach a level of residual free chlorine of 50 mg\/L or two hours a level of residual free chlorine of 20 mg\/L;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Perform routine analysis until the absence of bacteria of the Legionella genus (and other bacteria) is detected; if such does not happen, repeat the procedure described above;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Facing the occurrence of colonization of the building network\u2019s water by Legionella pneumophila, it is essential to avoid inhalation of aerosols and, therefore, impose a prohibition of the use of showers, hot tubs, etc.<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>If the water heaters and storage tanks are contaminated it is necessary to disinfect them before cleaning them;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>All personnel involved in these procedures must be highly specialized and properly trained, wearing individual protective gear.&nbsp;<\/li><\/ul>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">Thermal Disinfection<\/h3>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n\n<p>Consists typically in increasing the temperature of the water heaters or hot water tanks up to 70\u00b0 C, while circulating the water through the system for one hour.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>In points of consumption, faucets or showers, the water temperature should be 60\u00b0 C or higher for at least five minutes after opening, and preferably at the endpoints;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>The heat-disinfection should be performed weekly along with the bacteriological examination until the system is no longer under suspicion;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>For this procedure to be effective it is best if the hot water system is well insulated and allows to increase the temperature throughout the system up to 60\u00baC for at least one hour;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Upon the occurrence of one or more cases of Legionnaires&#8217; disease, follow all the procedures already covered for the cooling towers, like collecting samples at critical points for Legionella pneumophila research and carry out disinfection and cleaning of the entire network, using specialized and qualified staff to do so;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>All inspections, monitoring, maintenance and operations should be registered in a manual for easy access.&#8221;<\/li><\/ul>\n\n\n\n<p>In: Doen\u00e7a dos Legion\u00e1rios, Guia Pr\u00e1tico, Dire\u00e7\u00e3o-Geral da Sa\u00fade &amp; Dire\u00e7\u00e3o-Geral do Turismo, Lisboa 2001.<\/p>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Reference data and corrective actions for cooling towers and similar analogue devices, according to the microbiological analysis of Legionella:<\/strong><\/h3>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<figure class=\"wp-block-table alignwide is-style-stripes\"><table><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Legionella (cfu\/L) Count<\/strong><\/td><td><strong>Recommended Action<\/strong><\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   100&lt;1000 <\/strong><\/td><td>Review the maintenance program and make the necessary corrections<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">  <strong> 100&lt;1000 <\/strong><\/td><td>Conduct a new sampling after 15 days<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   1000&lt;10000 <\/strong><\/td><td>Review the maintenance program, in order to establish corrective actions to reduce the concentration of Legionella<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   1000&lt;10000 <\/strong><\/td><td>Conduct analysis after 15 days. If the result is &lt;100 cfu\/L, you should collect new samples after one month. If the result of the second sample is &lt;100 cfu\/L continues with the planned maintenance<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   1000&lt;10000 <\/strong><\/td><td>If one of the previous samples registers numbers &gt;100 cfu\/L, you should review the maintenance program and make the necessary structural changes<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"> <strong>  1000&lt;10000 <\/strong><\/td><td>If the numbers are higher than 1000 cfu\/L, you should clean and disinfect the system (a) and collect new samples after 15 days<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   &gt;10000 <\/strong><\/td><td>Shut down operations and, if necessary, drain the system<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>  &gt; 10000 <\/strong><\/td><td>Clean and perform a deep treatment according to (a), before restating operations<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>  &gt; 10000 <\/strong><\/td><td>Collect new samples after 15 days<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>(a)   Cleaning and disinfection in case of detection of Legionella.<\/strong><\/td><td><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<ul class=\"wp-block-list\"><li>Chlorinate the system water to get at least 20 mg\/L of free residual chlorine and add bio dispersants and compatible anticorrosive in adequate amount, keeping all fans off and, when possible, any opening, to prevent the output of aerosols;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Re-circulate the system for 3 hours, measuring the level of free residual chlorine hourly, replacing the lost amount;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Neutralize the chlorine and re-circulate the water in the same manner as the previous point;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Empty the system and rinse with pressurized water;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Clean the system\u2019s surfaces with detergent and pressurized water and rinse;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Introduce chlorine in the water flow in sufficient amount to reach 20 mg\/L of free residual chlorine, adding anticorrosive compatible with chlorine in adequate measure. Maintain for two hours, checking the free chlorine level every 30 minutes, restoring the amount lost. Re-circulate the water through the system, keeping the fans off and the openings closed;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Neutralize the chlorine and re-circulate the water in the same manner as the previous point;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Empty the system, clean it and add the maintenance disinfectant. When the disinfectant is chlorine, you should maintain a level of 2 mg\/L of free residual chlorine and add an anticorrosive compatible with chlorine in adequate measure;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>The removable parts should be cleaned and submerged in a solution containing 20mg\/L of free residual chlorine, for 20 minutes, and subsequently rinsed in abundant cold water. Elements difficult to disassemble or to access should be sprayed with the same solution during the same amount of time. As for equipment whose size or design does not enable spraying, cleaning and disinfection must be carried out through electric nebulising;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Subsequently, proceed with the usual maintenance measures.<\/li><\/ul>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Reference data and corrective actions for heated water systems for recreational use according to the microbiological analysis of Legionella<\/strong><\/h3>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-medium\"><\/div>\n\n\n\n<figure class=\"wp-block-table alignwide is-style-stripes\"><table><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>N\u00ba Legionella spp\/1000mL<\/strong><\/td><td><strong>Interpretation<\/strong><\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>&lt;10^2<\/strong><\/td><td>Under Control<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>\u226510^2 to \u226410^3<\/strong><\/td><td>Collect new samples for analysis and maintain increased vigilance<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>\u226510^2 to \u226410^3<\/strong><\/td><td>Advise the system manager to empty, clean and disinfect the system<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>\u226510^2 to \u226410^3<\/strong><\/td><td>Review the control measures and risk assessment; develop the identified corrective actions<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>\u226510^2 to \u226410^3<\/strong><\/td><td>After filling the basin, perform further analysis on the next day, and after 2-4 weeks<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   10^3 <\/strong><\/td><td>Immediate shutdown; evacuate the public within the vicinity of the basin<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   10^3 <\/strong><\/td><td>Proceed to shock disinfection of 50 mg\/L of free chlorine in circulation for one hour<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   10^3 <\/strong><\/td><td>Drain, clean and disinfect the basin<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   10^3 <\/strong><\/td><td>Review the control measures and risk assessment<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   10^3 <\/strong><\/td><td>After filling the basin, perform further analysis on the next day, and after 2-4 weeks<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>   10^3 <\/strong><\/td><td>Maintain shutdown until Legionella is no longer detected and the risk assessment is positive<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<div class=\"wp-block-kobu-custom-blocks-responsive-spacer responsive-spacer size-small\"><\/div>\n\n\n\n<p>In: Preven\u00e7\u00e3o e Controlo de Legionella nos Sistemas de \u00c1gua, Instituto Portugu\u00eas da Qualidade 2\u00ba Edi\u00e7\u00e3o 2014<br><br>(Health Protection Agency (UK) \u201cManagement of Spa Pools \u2013 Controlling the Risks of Infection\u201d March 2006.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u201cThe bacteria of the Legionella genus are found in natural aquatic environments and in artificial systems, such as supply networks\/water distribution, building [&hellip;]<\/p>\n","protected":false},"featured_media":2816,"menu_order":0,"template":"","mppost_cat":[22],"class_list":["post-972","mppost","type-mppost","status-publish","has-post-thumbnail","hentry","mppost_cat-treatment-suggestion","mppost-entry"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/mppost\/972","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/mppost"}],"about":[{"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/types\/mppost"}],"version-history":[{"count":3,"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/mppost\/972\/revisions"}],"predecessor-version":[{"id":2856,"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/mppost\/972\/revisions\/2856"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/media\/2816"}],"wp:attachment":[{"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/media?parent=972"}],"wp:term":[{"taxonomy":"mppost_cat","embeddable":true,"href":"https:\/\/aqualab.pt\/en\/wp-json\/wp\/v2\/mppost_cat?post=972"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}