Two cases of a novel strain of gonorrhea, a sexually transmitted disease, have been found, health officials in Massachusetts say.

Even though the patients improved once doctors treated them with ceftriaxone, the infections presented resistance to almost all medicines used to fight the disease, the New York Post reported Friday.

“This is the first time that resistance or reduced response to five classes of antibiotics has been identified in gonorrhea in the United States,” the Massachusetts Department of Public Health said in a press release Thursday, noting no direct connection between the patients was identified.

The department continued:

This strain of gonorrhea has been previously seen in Asia-Pacific countries and in the United Kingdom, but not in the US. A genetic marker common to these two Massachusetts residents was also previously seen in a case in Nevada, though that strain retained sensitivity to at least one class of antibiotics. Overall, these cases are an important reminder that strains of gonorrhea in the US are becoming less responsive to a limited arsenal of antibiotics.

Officials have alerted clinicians and laboratories about the strain.

Gonorrhea is a sexually transmitted disease (STD) individuals can contract from engaging in sex with an infected person, according to WebMD.

If a person does not seek treatment, he or she may experience serious problems such as an increased risk of contracting HIV, infections in other areas of the body, and infertility.

Gonorrhea usually affects the urethra, rectum, or throat, according to the Mayo Clinic.

“Gonorrhea is most commonly spread during vaginal, oral or anal sex,” the site read, adding, “Abstaining from sex, using a condom if you have sex and being in a mutually monogamous relationship are the best ways to prevent sexually transmitted infections.”

Gonorrhea is reportedly the second most common STD in the nation, the Post article said.

“The discovery of this strain of gonorrhea is a serious public health concern which DPH, the CDC, and other health departments have been vigilant about detecting in the US,” explained Massachusetts Public Health Commissioner Margret Cooke.

She also urged sexually active individuals to be tested on a regular basis for such infections and “consider reducing the number of their sexual partners and increasing their use of condoms when having sex.”

According to the department’s news release, cases of gonorrhea are on the rise in Massachusetts and across the country.