10 infants in California neonatal intensive care unit test positive for antibiotic resistant superbug

Infections were reported over eight months.

The 10 infants were reported to have tested positive for the same strain of methicillin-resistant Staphylococcus aureus (MRSA) between August 2016 and March 2017, according to a statement sent to ABC News by UC Irvine Medical Center. All infants were treated and none died after the bacteria was detected.

"Antibiotic resistance is growing, and we are fast running out of treatment options. If we leave it to market forces alone, the new antibiotics we most urgently need are not going to be developed in time," Dr Marie-Paule Kieny, WHO's Assistant Director-General for Health Systems and Innovation said in a statement.

"Its presence on a person does not necessarily cause illness and, as in this case, it’s not always possible to find the source," UC Irvine said in a statement to ABC News.

Although 220 staff underwent a process to pre-emptively kill any potential MRSA bacteria with antiseptic soap and ointemnt, the newest MRSA case was detected in March. Four staff members tested positive for MRSA in January but all are currently negative, according to the hospital statement.

"With the most recent MRSA case in March, we have repeated deep cleaning, continued attention to hand hygiene and repeated staff decolonization. We are currently testing staff to determine the effectiveness of this decolonization."

"Up to 10 percent of the population is colonized, you can't decontaminate the entire world," she said.

Additionally, she said completely decontaminating an area with patients can be a struggle as "it's hard to get every little bit of bacteria."

Edwards said doctors and nurses are generally extremely vigilant with infants in the NICU because they are more prone to all kinds of infections due to a weak immune system and invasive procedures.

"Their skin isn't always intact, they often need invasive surgery," she explained. "Anything that breaks the skin barrier is going to increase risk," of infection.

They also closed one of the two NICUs to new patients to better protect the newborns from possible infection.

"Our goal is to ensure the safety of our patients and eradicate the presence of any drug-resistant bacteria in our neonatal intensive care unit (NICU)," hospital officials said in a statement.

ABC News' Julie Sone contributed to this report.