Proteus mirabilis viability after lithotripsy of struvite calculi.
OBJECTIVE
We tested the hypotheses that Proteus mirabilis viability of struvite calculi differs after exposure to different lithotripsy modalities and that the photothermal mechanism of holmium:YAG lithotripsy is antibacterial.


METHODS
Human calculi of known struvite composition (greater than 90% magnesium ammonium phosphate hexohydrate) were incubated with P. mirabilis. Calculi were randomly distributed and fragmented with no lithotripsy (controls), or shock wave, intracorporeal ultrasonic, electrohydraulic, pneumatic, holmium:YAG or pulsed dye laser lithotripsy. After lithotripsy fragments were sonicated and specimens were serially plated for 48 hours at 38C. Bacterial counts and the rate of bacterial sterilization were compared.


RESULTS
Median bacterial counts (colony-forming units per ml.) were 8 x 10(6) in controls and 3 x 10(6) in shock wave, 3 x 10(7) in ultrasonic, 4 x 10(5) in electrohydraulic, 8 x 10(6) in pneumatic, 5 x 10(4) in holmium:YAG and 1 x 10(6) in pulsed dye laser lithotripsy cases (p <0.001). The rate of bacterial sterilization was 50% for holmium:YAG lithotripsy treated stones versus 0% for each of the other cohorts (p <0.01).


CONCLUSIONS
P. mirabilis viability varies among lithotrites. The photothermal mechanism of holmium:YAG lithotripsy is antibacterial.
Prabakharan
S
S
Department of Biology, Southwest Texas State University, San Marcos, USA.
Teichman
J M
JM
Spore
S S
SS
Sabanegh
E
E
Glickman
R D
RD
McLean
R J
RJ
D006801:Humans; D017616:Magnesium Compounds / Q000032:analysis*; D010710:Phosphates / Q000032:analysis*; D011513:Proteus mirabilis / Q000502:physiology*; D000069877:Struvite; D014545:Urinary Calculi / Q000737:chemistry* / Q000382:microbiology*
D017616:Magnesium Compounds; D010710:Phosphates; D000069877:Struvite