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Polymerase Chain Reaction and Dot-Blot Hybridization for Leptospira Detection in Water Samples
Published on: June 14, 2024
First isolation of human Leptospira strains, Azores, Portugal
Ana T Gonçalves1, Clara Paiva, Francisco Melo-Mota
1Unidade de Leptospirose e Borreliose de Lyme, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, Lisbon, Portugal.
Objectives:
The aim of this study was the first identification of Leptospira isolates from Azorean inpatients.
Methods:
Whole blood samples from 68 inpatients attending the São Miguel Hospital between 2006 and 2008, with a clinical and epidemiological suspicion of leptospirosis, were inoculated in a transport medium broth at the patient's bedside and further processed using a serial dilution technique prior to culture. At admission, 62 (91%) patients were also analyzed for the presence of leptospiral DNA by a nested PCR and 40 (59%) for specific agglutinins by microscopic agglutination test (MAT). The isolates obtained were first assigned at the serogroup level by both MAT reactivity with hyperimmune rabbit antisera and a PCR-based assay with the single primer iRep1. The species identification was performed by DNA sequencing. The use of monoclonal antibodies allowed intraspecific discrimination at the serovar level.
Results:
Of the 10 (14.7%) human Leptospira isolates, seven were identified as Leptospira interrogans serovar Copenhageni and three as Leptospira borgpetersenii serovar Arborea, which is in agreement with previous data from the Azorean rodent population.
Conclusions:
This study represents a great step towards the definitive identification of the pathogenic leptospires in Azorean patients and confirms the bacteriological human-rodent connection for the first time.
Insights
This study identified Leptospira interrogans and Leptospira borgpetersenii in Azorean patients, confirming a link between human and rodent infections. This research advances the understanding of leptospirosis in the Azores.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Leptospirosis is a significant zoonotic disease.
- Previous studies have indicated a potential link between rodent and human infections in the Azores.
- Limited data exists on the specific Leptospira species circulating in Azorean inpatients.
Purpose of the Study:
- To identify Leptospira isolates from patients in the Azores for the first time.
- To determine the species and serovars of pathogenic leptospires in Azorean inpatients.
- To establish a bacteriological connection between human and rodent leptospirosis in the region.
Main Methods:
- Collected blood samples from 68 inpatients with suspected leptospirosis (2006-2008).
- Utilized bacterial culture, nested PCR for DNA detection, and microscopic agglutination test (MAT) for serological analysis.
- Employed DNA sequencing and monoclonal antibodies for precise species and serovar identification.
Main Results:
- Successfully isolated Leptospira from 10 (14.7%) patients.
- Identified seven isolates as Leptospira interrogans serovar Copenhageni.
- Identified three isolates as Leptospira borgpetersenii serovar Arborea, consistent with Azorean rodent data.
Conclusions:
- This study provides the first definitive identification of pathogenic leptospires in Azorean patients.
- Confirms a direct bacteriological link between human and rodent populations regarding leptospirosis in the Azores.
- Highlights the importance of ongoing surveillance and identification of Leptospira species in public health.
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