Incidents, such as the recent one involving the presence of Legionella in a nursing home, should serve as a catalyst for strengthening scientific vigilance and prevention systems, not only in a specific hospital but throughout the entire healthcare system, said to CNA, Professor of Pediatrics and Epidemiology and Associate Dean for Research at the University of Nicosia (UNIC) School of Medicine, Zoe Dorothea Pana, noting at the same time that infection prevention is a fundamental indicator of the quality and safety of health services
“Although Legionnaires’ disease occurs more frequently in adults, especially the elderly and immunocompromised, it can, albeit rarely, affect newborns, in whom it may cause a particularly severe infection,” said Ms. Pana.
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It is important, she explained, “to distinguish between three different issues: the clinical management of the newborn, the epidemiological investigation of the possible source of exposure, and the evaluation of prevention and control measures at the hospital.”
“These are interrelated but scientifically distinct processes,” she added.
When asked why newborns are considered particularly vulnerable to Legionella and which defense mechanisms have not yet fully developed, Ms. Pana said that newborns constitute a special population group, as their immune system is still in the process of development and functional maturation.
“This does not mean that they lack immune protection, but that certain defense mechanisms do not yet function as effectively as they do in older individuals,” she noted.
“Legionella pneumophila, the primary bacterial species that causes Legionnaires’ disease, has the unique ability to survive and multiply inside macrophages, that is, cells of the immune system that normally help neutralize microorganisms,” he said.
“Effectively combating it depends to a significant extent on cellular immunity and the proper activation of macrophages,” she added.
Ms. Pana noted that in newborns, developmental peculiarities are observed in both the innate and adaptive immune responses, including phagocyte function, the production of specific cytokines, and T-cell immunity.
“Furthermore, respiratory defense mechanisms, such as mucociliary clearance, are still in the process of maturing,” he said.
Newborns, she explained, “also have lower reserves of respiratory function, meaning that a severe pulmonary infection can lead more quickly to respiratory distress.”
According to her, “preterm infants, as well as those with underlying medical conditions or who require intensive care, may be particularly vulnerable.”
“We must, however, emphasize that neonatal Legionnaires’ disease is extremely rare,” he noted, adding that scientific knowledge regarding its prevalence, specific risk factors, and prognosis comes primarily from published case reports and small case series.
When asked what the typical symptoms are in a newborn just a few days old and how easy it is to diagnose the condition early, Dr. Pana said that Legionnaires’ disease is a severe form of bacterial pneumonia. In newborns, however, the clinical presentation may be nonspecific and resemble other serious neonatal infections.
As he noted, symptoms may include tachypnea, respiratory distress, hypoxemia, or episodes of apnea, fever, or, conversely, hypothermia, decreased feeding, lethargy, hypotonia, or irritability, progressive deterioration of respiratory function, and, in severe cases, respiratory failure.
“Diagnosis is particularly challenging because the symptoms are not specific to Legionella. Furthermore, the infection is so rare in the neonatal period that it is not always included among the initial diagnostic considerations,” he said.
Laboratory investigation may include molecular tests, such as PCR on appropriate samples from the lower respiratory tract, as well as culture on specialized media. Urinary antigen detection can be helpful, but it has a significant limitation: it primarily detects Legionella pneumophila serogroup 1, and therefore a negative result does not rule out the disease. “The selection and interpretation of tests in newborns require specialized evaluation,” he added.
He noted that the key message is that early clinical suspicion, appropriate laboratory diagnosis, and the immediate initiation of effective treatment are critical factors in managing the infection.
In response to a question about the possible long-term complications for a newborn who has overcome the immediate danger, Ms. Pana said that the long-term prognosis depends primarily on the severity of the initial lung infection, the extent of lung damage, the duration of respiratory support, and the presence of any complications.
“In severe cases of pneumonia, regardless of the causative microorganism, prolonged respiratory dysfunction or the need for long-term follow-up may be observed,”, he noted.
He referred to possible complications of severe neonatal pneumonia, which include persistent respiratory distress and, in cases of significant lung damage, structural changes in the pulmonary parenchyma. “If the infection was accompanied by prolonged severe hypoxemia or multi-organ dysfunction, developmental or neurological monitoring may also be necessary,” she noted.
However, Ms. Pana continued, scientific caution is warranted: there is insufficient data to reliably determine the frequency of permanent complications, especially following neonatal Legionnaires’ disease.
“It would be incorrect to assume that every newborn who recovers will experience long-term problems. On the contrary, full recovery is possible. Follow-up should be tailored to the child’s clinical course,” he added.
Mode of transmission, water supply systems, and epidemiological tracing
When asked how a newborn might become infected in a hospital setting, Ms. Pana said that Legionella is an environmental, waterborne bacterium that can survive and multiply in artificial water systems, especially when conditions are favorable for its growth.
“The most common route of transmission is the inhalation of very small water droplets, known as aerosols, that contain the bacterium. In a hospital, potential exposure sites may include faucets, showers, and other facilities or devices that produce aerosols from contaminated water,” she added.
In newborns, Ms. Pana said, there are additional specific conditions that require attention.
“Exposure may be related to the use of water during bathing or personal hygiene, provided that contaminated droplets are generated and inhaled, the use of respiratory care devices or humidifiers, if unsuitable or microbiologically contaminated water is used, and the ingestion of water containing Legionella, particularly in vulnerable patients,” he said.
Here, he noted, “it is important to clarify that medical respiratory support devices must use appropriate sterilized water, in accordance with the manufacturer’s specifications and infection prevention protocols, and not plain tap water.”
He also noted that the detection of the bacterium at two points in a water supply system is a significant environmental finding, but does not in itself prove what the exact route of transmission was or that those specific points caused the infection.
“This requires a combined clinical, epidemiological, and microbiological investigation. Where possible, comparing clinical and environmental isolates using molecular methods can significantly strengthen the evidence regarding the likely source,” he added.
When asked about the incubation period and how it helps determine the point and time of infection, Ms. Pana said that the typical incubation period for Legionnaires’ disease is approximately 2 to 10 days after exposure, although longer periods have been reported, up to about 14 days and, more rarely, longer.
“For newborns, the available data are limited and do not allow us to definitively establish a distinct, specific incubation period. From an epidemiological standpoint, the incubation period is particularly useful because it allows scientists to trace potential exposures that preceded the onset of symptoms,” he said.
In the case of a newborn, he explained, “the timeline from birth to the onset of the disease is examined in detail: the facilities where the infant was treated, care procedures, water use, and potential sources of exposure.”
“It must be emphasized, however, that the incubation period alone cannot determine the exact time or source of infection. It can narrow down the possible time window of exposure, but the final assessment is based on the totality of the findings,” he added.
Prevention, Protocols, and Hospital Safety
Noting that the risk of Legionella outbreaks in hospitals cannot be completely eliminated, but asking what the necessary prevention and control measures are, Ms. Pana said that it is scientifically accurate to state that we cannot guarantee a zero risk of Legionella in any water supply system.
“However, this does not mean that the risk is uncontrollable or that the occurrence of an infection is inevitable. On the contrary, there are internationally recognized measures that can substantially limit the proliferation and spread of the bacterium,” he added.
He noted that Legionella thrives at temperatures of approximately 25–45°C, particularly when stagnant water, sediments, and biofilms are present.
“These are microbial communities that adhere to the inner surfaces of pipes and can protect microorganisms from standard disinfection procedures,” she added.
According to the guidelines of the World Health Organization and the U.S. CDC, Ms. Pana said, every healthcare facility needs a comprehensive Water Management Program, which includes systematic temperature monitoring.
“Hot water should be stored at temperatures above 60°C and maintained at a sufficiently high temperature as it circulates, while cold water should remain as low as possible, ideally below 20°C. Technical adjustments must be combined with protection against scalding, especially for newborns and children,” he added.
Second, he said, it involves maintaining effective disinfection.
“It is necessary to monitor the concentration of residual disinfectant, such as chlorine, at representative points in the network. Chlorination, however, is not in itself a guarantee of safety,” he noted.
Third, he said, it involves preventing water stagnation.
“This requires a steady flow, maintenance of the facilities, and identification of sections of the network with limited or no circulation,” he added.
Fourth, he continued, it involves systematic technical maintenance, including the inspection of tanks, water heaters, faucets, filters, aerators, and other components that may promote the formation of biofilms.
Fifth, he said, involves environmental microbiological surveillance based on risk assessment.
“The frequency and sampling points should be determined by the structure of the network, the presence of vulnerable patients, the history of test results, and applicable requirements,” he added.
Sixth, he noted, it includes specific protective measures for high-risk units.
“In neonatal units, transplant units, and other areas with particularly vulnerable patients, water management must take into account the increased vulnerability of the population. Depending on the risk, appropriate point-of-use filters and strict restrictions on water use may be required,” she added.
As Ms. Pana said, a key element is the existence of clearly defined responsibilities and documented control procedures, with collaboration between the technical department, management, and the infection prevention and control team.
“Legionella prevention cannot be limited to occasional disinfection or a single laboratory test. It requires continuous, organized, and documented risk management,” she noted.
When asked, in light of the temporary suspension of the clinic’s services, how the disinfection of a water supply system is carried out and when it is considered safe again, Ms. Pana said that restoring the microbiological safety of a water supply system is a complex technical and public health process.
“It is not enough to simply add chlorine or raise the temperature for a limited period of time,” she clarified.
The first step, according to her, “is a comprehensive assessment of the water supply system to identify potential sites for Legionella growth and the factors that allowed it to develop.”
“This is followed by the selection of an appropriate remediation method, which may include chemical disinfection, such as hyperchlorination, or other technical interventions, depending on the characteristics of the network,” she added.
He noted that thermal disinfection, also known as thermal shock, has been used as a treatment method.
“However, the latest CDC guidelines point out that it should not be considered the preferred or sole solution for drinking water systems, as its effectiveness may be temporary, and there are risks of scalding and technical limitations,” he said.
Equally important, he added, “is addressing the underlying problems in the system, such as stagnation, inappropriate temperatures, and biofilms.”
“Otherwise, there is a possibility that the bacteria will reappear after the initial intervention. After restoration, a risk reassessment, a check of operational parameters, and appropriate follow-up microbiological sampling are required,” he added.
She also stated that the resumption of operations in the affected services must be based on a documented safety assessment, in accordance with the guidelines of the competent authorities and specialized scientists.
Ms. Pana emphasized that “a single negative sample is not always sufficient to demonstrate that the risk has been definitively controlled. The assessment must take into account the overall results, the effectiveness of the interventions, and the ability to maintain safe conditions over the long term.”
““The goal is not merely to achieve a negative laboratory result, but to ensure that the system operates under conditions that consistently limit the likelihood of Legionella growth and transmission,” he noted.
When asked what kind of recommendations or educational interventions should be implemented immediately for healthcare professionals in Cyprus, Ms. Pana said she believes that such incidents should serve as an opportunity to strengthen scientific vigilance and prevention systems, not only in a specific hospital but throughout the entire healthcare system.
“Training must be interdisciplinary in nature and target physicians, nurses, infection prevention and control professionals, microbiologists, technical staff, and hospital administrators,” he added.
He also noted that priority should be given to three key areas: early recognition and diagnosis, the prevention of waterborne infections, and organized surveillance and risk management.
Cooperation between the clinical team and technical services is of particular importance, Ms. Pana continued.
“Water safety is not the exclusive responsibility of either doctors or engineers,” she said.
It is a shared responsibility, she emphasized, “which requires institutional organization and clear accountability. It would also be useful to develop or update national, harmonized protocols for managing the risk of Legionella in healthcare facilities, with particular reference to vulnerable populations and compliance monitoring mechanisms.”
According to Ms. Pana, Legionella reminds us that patient safety depends not only on the quality of medical care, but also on the safety of the environment in which it is provided.
“Water is essential for the operation of any healthcare facility. Under certain conditions, however, it can be a source of exposure to microorganisms that cause serious infections, especially in the most vulnerable patients,” she said, adding that “when it comes to a newborn, the need for protection is even greater.”
“We must address such incidents with scientific rigor, transparency, and respect for the family, without jumping to conclusions about the source of the infection or assigning blame before the investigation is complete,” he noted.
At the same time, he said, “the rarity of an infection should not lead to an underestimation of the risk. Prevention must be systematic and proactive.”
The most important message, he noted, “is that infection prevention is a fundamental indicator of the quality and safety of health care services.”
“It is not enough to react when an incident occurs; we must have systems in place that identify, assess, and mitigate risks before they lead to an infection,” he said.
“Scientific knowledge, continuous education, effective surveillance, and cooperation among all relevant professionals are the most important prerequisites for protecting patients and maintaining public trust in the healthcare system,” he concluded.
Source: CNA
