Characterization of Leptospira isolates from humans and the environment in Uruguay

Abstract

Laboratory diagnosis of human leptospirosis usually relies on indirect methods exploring specific immune response. Isolation and identification of the involved strains are cumbersome, but can provide biological resources for pathogenic studies and relevant information for guiding prevention and control measures. The aim of the research we are hereby reporting was the characterization of Leptospira isolates obtained from humans and the environment in Uruguay. Blood cultures were performed from early samples of 302 Uruguayan patients, mainly rural workers, and from 36 water samples taken from their living or working environments. Eight human isolates and seven environmental isolates were obtained and analyzed by end point Polymerase Chain Reaction (PCR), Multilocus Variable Number of Tandem Repeat Analysis (MLVA) and other molecular methods. Human isolates corresponded to several serogroups and serovars of Leptospira interrogans and Leptospira kirschneri species, probably reflecting the infection with similar involved Leptospira species and serovars of an extended animal reservoir in rural settings of the country, mostly dedicated to meat and dairy production. Culture-positive patients were older than usually affected workers, and presented signs and symptoms of severe illness. A high organic and circulating bacterial burden may explain an easier positive result from these workers’ samples. Environmental isolates were mainly identified as Leptospira biflexa strains, with a single L. meyeri isolate of uncertain significance.

Leptospira interrogansserogroup Pomona serovar Kennewicki infection in two sheep flocks with acute leptospirosis in Uruguay

“…From the 12 lipL32 ‐positive samples, amplicons of rrs from urine (three samples from Farm I and four from Farm II) and one from kidney of one deceased lamb (Farm I), yielded sequences with 100% of identity to Leptospira interrogans . Phylogeny based on secY gene sequence analysis revealed that all eight sequences obtained directly from clinical samples and the sequences obtained from L. interrogans serovar Kennewicki isolates IP1712053 and IP1712058 cluster in one group, together with L. interrogans serovar Kennewicki previously isolated from cattle (Zarantonelli et al., ) and from a rural worker (Meny et al., ) in Uruguay, as well as with a reference strain L. interrogans serovar Pomona (Figure ).…”

“…Three of the 10 sera tested on Farm II were positive against serogroup Pomona, with titres ranging from 50 to 3,200 (Table 1). interrogans serovar Kennewicki isolates IP1712053 and IP1712058 cluster in one group, together with L. interrogans serovar Kennewicki previously isolated from cattle (Zarantonelli et al, 2018) and from a rural worker (Meny et al, 2017) in Uruguay, as well as with a reference strain L. interrogans serovar Pomona (Figure 2).…”

“…Swine can be a natural reservoir or a maintenance host for Pomona serogroup strains (Ellis, ), and recently the serovar Kennewicki was the single most frequent serovar isolated from cattle (Zarantonelli et al., ). This serovar has also been isolated from a rural worker in Uruguay (Meny et al., ). All L. interrogans serovar Kennewicki isolates from cattle, human and sheep are genetically related since they clustered together in the same secY homogeneous clade, suggesting that this serovar is causing animal and public health problems.…”

“…Swine can be a natural reservoir or a maintenance host for Pomona serogroup strains (Ellis, 2015), and recently the serovar Kennewicki was the single most frequent serovar isolated from cattle (Zarantonelli et al, 2018). This serovar has also been isolated from a rural worker in Uruguay (Meny et al, 2017). All L.…”

Leptospira interrogans and Leptospira kirschneri are the dominant Leptospira species causing human leptospirosis in Central Malaysia

“…All three species have been previously isolated and identified from humans, animals or the environment in Malaysia. L. kirschneri and L. interrogans, the most common and widely distributed Leptospira species from rodents and small mammals [13,30,[47][48][49][50][51] were identified as the main human-infecting Leptospira species in Malaysia based on our study. L. wolffii, an intermediate species was detected in the blood of two patients.…”