Ability of Escherichia coli to produce hemolysis leads to a greater pathogenic effect on human sperm.
OBJECTIVE
To determine the effect on human sperm of Escherichia coli strains separated on the basis of their ability to produce hemolysis.


METHODS
Experimental study.


METHODS
University-based laboratory.


METHODS
Semen samples from healthy donors.


METHODS
Five million sperm, selected via the swim-up method, were incubated with 3 E. coli concentrations to obtain ratios of sperm to E. coli of 1:2, 1:16, and 1:128. The E. coli strains were: a hemolytic isolated strain (H), a nonhemolytic American Type Culture Collection strain (NH-ATCC), and a nonhemolytic isolated strain (NH-I).


METHODS
Aliquots of human sperm were used to measure progressive motility using computer-aided sperm analysis, mitochondrial membrane potential (ΔΨm) with a JC-1 (5,5',6,6' tetrachloro-1,1',3,3'-tetraethylbenzamidazolocarbocyanin iodide) and propidium iodide stain, and intracellular reactive oxygen species (iROS) with a dihydroethidium (DHE) stain. Sperm ΔΨm and iROS were measured by flow cytometry. Sperm vitality was considered the mean of propidium iodide-negative and DHE-negative cells.


RESULTS
Sperm incubated with the H strain in a 1:2 sperm to bacteria ratio demonstrated a significant decrease in motility and ΔΨm, and an increase of iROS. The NH-ATCC strain decreased sperm motility and ΔΨm, but in a ratio of sperm to bacteria of 1:128; it increased iROS at a ratio of 1:16. The NH-I strain did not affect the analyzed sperm functions, even at a 1:128 sperm to bacteria ratio.


CONCLUSIONS
Results show a greater pathogenic effect on human sperm of E. coli strains with, versus without, hemolytic capacity.
Centre of Reproductive Biotechnology (CEBIOR), Scientific and Technological Bioresources Nucleus (BIOREN), Temuco, Chile.
Rodrigo
R
Boguen
Centre of Reproductive Biotechnology (CEBIOR), Scientific and Technological Bioresources Nucleus (BIOREN), Temuco, Chile.
Favian
F
Treulen
Centre of Reproductive Biotechnology (CEBIOR), Scientific and Technological Bioresources Nucleus (BIOREN), Temuco, Chile.
Pamela
P
Uribe
Centre of Reproductive Biotechnology (CEBIOR), Scientific and Technological Bioresources Nucleus (BIOREN), Temuco, Chile; Department of Internal Medicine, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile. Electronic address: juana.villegas@ufrontera.cl.
Juana V
JV
Villegas
D002470:Cell Survival; D004926:Escherichia coli / Q000145:classification / Q000472:pathogenicity*; D006461:Hemolysis; D006801:Humans; D008297:Male; D053078:Membrane Potential, Mitochondrial; D017382:Reactive Oxygen Species / Q000378:metabolism; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism / Q000382:microbiology*
D017382:Reactive Oxygen Species
Human spermatozoa; mitochondrial membrane potential; motility; reactive oxygen species; uropathogenic Escherichia coli