Prevalence of Nosocomial Legionella Pneumophila in a Liver Transplant Unit: Clinical and Environmental Study
Dalia Moemen *
Department of Microbiology and Immunology, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
Weaam Shakra
Department of Botany, Faculty of Science, Zagazig University, Zagazig, Egypt.
Ashraf Elshawadfy
Department of Botany, Faculty of Science, Zagazig University, Zagazig, Egypt.
Abdou El-Mougith
Department of Botany, Faculty of Science, Zagazig University, Zagazig, Egypt.
Mohamed Elsaadany
Department of Gastroentrology Surgery, Faculty of Medicine, Mansoura University, Mansoura, Egypt.
*Author to whom correspondence should be addressed.
Abstract
Aims: Legionella pneumophila (L. pneumophila) is a human pathogenic bacteria associated with aquatic habitat. It is a causative agent of sever pneumonia known as Legionnaires’ disease (LD). LD among liver transplant recipients (LTRs) is difficult to diagnose with routine methods.
Study Design: Thus the current study was designed to detect Legionella in clinical samples as well as environmental samples in the liver transplant unit of Gastroenterology Surgical Center (GEC), from November, 2014 till June, 2016.
Methods: Respiratory, urine and blood samples were collected from 30 LTRs who were hospitalized with signs and symptoms of lower respiratory tract infections. The specimens were screened for Legionella by plate culture method, urinary antigen detection and serological investigation. A total of 40 environmental samples from hospital water and air ventilation system of the same unit were collected and analyzed for the occurrence of Legionella. The minimum inhibitory concentration (MICs) of L. pneumophila isolates against 8 antimicrobials were determined.
Results: The prevalence of nosocomial Legionella pneumonia was 20%. Six patients were positive for L. pneumophila by culture, among those, urine antigen was detected in five patients and serum investigation yielded positive in three patients. L. pneumophila was recovered from five water samples (12.5%). Azithromycin was found to be the most active against Legionella isolates in vitro. Chlorine (2 mg/L) and superheating (70°C) of hospital water successfully eradicated L. pneumophila.
Conclusion: For hospital with transplant units, periodic monitoring of Legionella in hospital water supply and introducing diagnostic tests for LD for patients with nosocomial pneumonia is necessary.
Keywords: Nosocomial pneumonia, Legionella pneumophila, Legionnaires’ disease, liver transplant recipients, hospital water contamination