Transvaginal Ultrasound in rare cases causing STD

A few weeks ago, I came across an online article about women that had been infected with an STD from a procedure at their gynecologist office. The article stated that several women had been diagnosed with Chlamydia and HPV and other STD's after having a Transvaginal ultrasound. . Ai says it is very rare but that infections can be transmitted from the ultrasound probe if the probe isn't properly covered and disinfected. Has anyone else heard of this or heard stories of this? Yikes!

Disinfecting tools and washing hands have been part of medicine for two or three centuries now. Sometimes, careless people forget this.

All of these women went to the same gynecologist I presume? I would be quite curious to find out more detail. Did the local health department put the puzzle together, were these ladies friends and discovered within their own circle that they all went to the same medical practice?