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Evaluation of preservation methods and solid media suitable for recovery of Ureaplasma urealyticum from transported
Abstract:
Urine specimens to be tested for Ureaplasma urealyticum (T-strain mycoplasma) must often be transported to a central laboratory for identification. To examine survival of these organisms over 2 days of transport, fresh urine samples were tested for the presence of ureaplasmas and then divided into four groups: (i) fresh, (ii) frozen, (iii) preserved with 1% (wt/vol) boric acid at room temperature, and (iv) preserved with 10% dimethyl sulfoxide and frozen. The samples were cultured on both A7 and New York City solid media, and the estimates of survival were compared to that of fresh urine. Less than 10% survival of Ureaplasma was observed in 11 of 14 specimens stored frozen for 2 days without preservation; six specimens lost all organisms. Specimens containing either dimethyl sulfoxide or boric acid showed higher survival rates, although neither method consistently approached the full recovery of the T-strains found with the fresh urine. Ureaplasmas from fresh specimens grew well on both New York City and A7 media; however, the New York City medium proved superior for those preserved with boric acid and for urine samples containing few ureaplasmas. These results indicate that preservation of samples does increase the yield of U. urealyticum from urine samples delayed in transit.
Insights
Preserving urine samples with boric acid or dimethyl sulfoxide improves Ureaplasma urealyticum (T-strain mycoplasma) survival during transport. These methods enhance recovery rates compared to freezing alone, aiding laboratory identification.
Area of Science:
- Microbiology
- Clinical Diagnostics
- Urology
Background:
- Ureaplasma urealyticum (T-strain mycoplasma) identification requires laboratory testing of urine specimens.
- Specimen transport to central labs can compromise organism viability, impacting diagnostic accuracy.
Purpose of the Study:
- To evaluate the survival of Ureaplasma urealyticum in urine specimens during a 2-day transport period.
- To compare the efficacy of different preservation methods (freezing, boric acid, dimethyl sulfoxide) on organism survival.
Main Methods:
- Urine samples were divided into four groups: fresh, frozen, preserved with 1% boric acid, and preserved with 10% dimethyl sulfoxide and frozen.
- Samples were cultured on A7 and New York City (NYC) solid media.
- Organism survival was assessed by comparing colony counts to fresh specimens.
Main Results:
- Freezing without preservation resulted in <10% Ureaplasma survival in 11/14 specimens, with complete loss in six.
- Boric acid and dimethyl sulfoxide preservation significantly increased Ureaplasma survival rates.
- NYC medium demonstrated superior performance for preserved samples and those with low initial organism counts.
Conclusions:
- Preservation methods are crucial for maintaining Ureaplasma urealyticum viability in urine samples during delayed transport.
- Boric acid and dimethyl sulfoxide offer improved preservation compared to freezing alone, enhancing diagnostic yield.