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Urogenital Mycoplasmas

Urogenital Mycoplasmas

Seeing the doctor about concerns of sexually transmitted infections (STIs) or urinary tract infections (UTIs) can be very uncomfortable for most people…

However, it’s something that millions of Americans are compelled to do every year. According to the CDC, nearly 2.3 million cases of chlamydia, gonorrhea, and syphilis (the most common STIs) were reported in the US in 2017. This number shows a 31% increase from the 1.8 million reported cases in 2013.

The majority of STI screens primarily detect Chlamydia trachomatis (chlamydia), Neisseria gonorrhoeae (gonorrhea), Treponema pallidum subsp. pallidum (syphilis), Trichomonas vaginalis (trichomoniasis), hepatitis B virus, and human immunodeficiency virus (HIV). However, another group of bacteria (Mollicutes) that can cause STIs and UTIs and are often overlooked and not getting the attention they deserve.

The genital Mollicutes of concern consist of the bacterial genera Mycoplasma and Ureaplasma, which are unique bacteria in that they lack a bacterial cell wall. They are some of the smallest free-living organisms and can either be pathogenic or commensal in humans. They have complex nutritional and cultivation requirements that demand special and laborious techniques for laboratory detection and characterization, which can discourage clinical microbiology laboratories from performing regular cultures in-house. 

                The reference method for the detection of Mycoplasma and Ureaplasma is culture-based, typically on A8 agar. Nevertheless, due to the insensitivity of culture, requirement of specific media and the length of the culture (typically a few days to a couple of weeks for colony maturation), the optimal detection method is PCR-based. However, in the clinical setting, detecting these urogenital mycoplasmas is rarely urgent, so labs may elect to not use PCR because of this and the high costs associated.

Historically, these organisms have not been studied closely due to their fastidious nature and small size. Traditionally, they are not considered nor screened for in the initial STI or UTI battery of tests. However, Mycoplasma hominis and Ureaplasma urealyticum can cause some serious infections and conditions if misidentified. Microscopically, on A8 agar, Mycoplasma hominis mimic a “fried-egg” morphology (see below).
“Fried-egg” shaped cells of M. hominis.

M. hominis has been isolated from the upper urinary tract in patients with acute pyelonephritis, a kidney infection that causes pain and inflammation. M. hominis infection during pregnancy can cause ectopic pregnancy, early delivery, or miscarriage, and can induce fever among newborns. U. urealyticum causes non-chlamydial, non-gonococcal urethritis (NGU). In newborns, an U. urealyticum infection during pregnancy can cause low birth weight, pneumonia, and septicemia.

These microorganisms are typically transmitted via sexual contact or vertical transmission (mother to child) and may go seemingly unnoticed depending on the patient’s immune system health. Although M. hominis and U. urealyticum can be present in the commensal flora of many humans, when they exceed concentrations of 104 and 103 CCU/mL, respectively, these bacteria can often lead to urogenital tract infections.

Although these bacteria can exist in the commensal flora of many humans, their unmonitored proliferation can prove pathogenic. It is quite common that when one is suffering from STI or UTI-related symptoms, a Mycoplasma test is often the last test ordered by the clinician, only after all other pathogen possibilities haven been exhausted and all laboratory results return negative.  Beta-lactams (including penicillins and cephalosporins) are ineffective against these organisms because they lack a cell wall. Therefore, doxycycline, macrolides (eg. azithromycin), and fluoroquinolones are often used to treat these infections. 

Luckily, there is a device that can detect, identify, and enumerate Mycoplasma hominis and Ureaplasma urealyticum from endocervical, urethral, urinary, gastric and sperm specimens in as little as 24 hours. This device is called Mycofast US by ELITech and is now for sale in the US by Hardy Diagnostics. This “all liquid”, rapid colorimetric test relies on innate properties of M. hominis and U. urealyticum for detection and identification, and patented techniques for enumeration. The color pattern of wells in the device is used to interpret the results of the test. A positive result indicates that Mycoplasma hominis and/or Ureaplasma urealyticum are present in the specimen tested, either colonization or infection. However, the positive test alone should not be used to make a clinical diagnosis. The diagnosis should be determined by the physician based on the correlation between the culture results and the clinical symptoms present.

This test is a great compromise between the traditional Mycoplasma culture and PCR methods because of two main characteristics: 1) Time – results can be achieved in as little as 24 hours, 48 hours for strains with weaker enzymatic activity, which is considerably quicker than the weeks required for typical cultivation and 2) Money – this test is less expensive than PCR-based detection methods. Order your very own box of 30 MYCOFAST US tests (cat. no. 00050) at today.

by Dylan Campbell and Andre Hsiung

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