Doctors identify drug-resistant bacteria in study

Infectious disease doctors at Samsung Medical Center have discovered a new family of pathogens that is resistant to eight antibiotics and affected five elderly Korean patients between 2011 and 2012, according to recently released research.

The research team said that the bacteria, extensively drug-resistant Streptococcus pneumoniae, is the deadliest discovered yet and insusceptible to most of the antibiotics among existing pathogens. Streptococcus pneumoniae, which can cause pneumonia, among other ailments, is one of the most common bacterial respiratory pathogens.

For their research, the center’s team conducted a study of 520 people infected with Streptococcus pneumonia, and concluded that five of them had contracted the deadliest strain of the pathogen. Three of them were infected in nursing hospitals and two in long-term nursing care facilities. The average age of the five patients was 71.8, indicating that the elderly are most susceptible to the drug-defying bacteria.

All five had been hospitalized long-term or were living in a nursing home and had compromised immune systems. One of the five passed away primarily due to the bacteria.

“We can’t find bacteria as deadly as this [extensively drug resistant Streptococcus pneumoniae],” said Kang Cheol-in, a doctor in the infectious diseases division at Samsung Medical Center who participated in the research. “The five patients never responded to the eight antibiotics.”

The research was released in the May 2014 edition of Emerging Infectious Diseases, a journal issued by the U.S. Centers for Disease Control and Prevention (CDC). Korea is not alone in grappling with the prevalence of the antibiotic-resistant bacteria. Over the last decade, antimicrobial resistance has increased worldwide.

Resistance to penicillin and macrolide antibiotics, in particular, has spread rapidly among Streptococcus pneumonia isolates, a population of organisms in which there is little genetic mixing. According to the CDC, among Streptococcus pneumonia isolates obtained from pediatric patients, the percentage exhibiting resistance to penicillin increased each year after 1994, reaching 45 percent in 2000.

Traditional Streptococcus pneumonia pathogens were resistant to only three to four antibiotics and categorized as multidrug-resistant. The new bacteria is reportedly resistant to penicillin, cephalosporins and macrolides as well as tetracyclines and trimethoprim-sulfamethoxazole.

BY PARK EUN-JEE [ejpark@joongang.co.kr]