Increase In Drug Resistance For Common Bacterium Termed “Rocket Ship”

TORONTO -- By the year 2000, half of the infections caused by the bacterium responsible for 7 million cases of otitis media in children and 500,000 cases of pneumonia in children and adults each year in the U.S. will have some resistance to penicillin, an associate professor of pharmacy at the University at Buffalo warned today.

Already, according to a national study conducted by researchers at UB, Buffalo’s Millard Fillmore Hospital and the University of Iowa College of Medicine, 32 percent of infections caused by Streptococcus pneumoniae are resistant to penicillin to some extent and about 10 percent are susceptible to few oral antibiotics. The former are termed highly resistant infections and the latter are described as showing intermediate resistance.

And from 1994-97, the study showed, there was a 40 percent increase in intermediate-resistant Streptococcus pneumoniae infections and a 30 percent rise in those considered highly resistant.

“This is a rocket ship,” Charles Ballow, Pharm.D., reported here today (Sept. 30, 1997) at the InterScience Conference on Anti-Microbial Agents and Chemotherapy.

Ballow, director of Anti-Infectives Research in the Clinical Pharmacokinetics Laboratory at Millard Fillmore Hospital, reported on a study that looked at regional trends of bacterial resistance based on more than 4,000 Streptococcus pneumoniae samples from hospital and community patients processed by 192 hospital laboratories from May 1996 to May 1997.

The study, he noted, showed that resistance varies by geographic region of the U.S., and is found most often in the Southeast.

Ballow said 40 percent of the Streptococcus pneumoniae samples from the Southeast were resistant to penicillin, while in the Midwest the rate was 36 percent, and in the Northeast and the West it was closer to 29 percent.

The overall resistance rate in the U.S. for the bacterium was 32 percent.

Identifying a cause for the higher rate of resistance in the Southeast is difficult, Ballow said.

“It could be that one major hospital in the region has really poor infection-control standards,” he said. “With this study, we have dissected the U.S. by region. Now we want to dissect it by hospital laboratory to see if there’s one major metropolitan area in the Southeast that is skewing the results for the region.”

Ballow stressed that while the regional differences in bacterial resistance are important, the rate of increase that is being seen nationwide is especially alarming.

Ballow characterized Streptococcus pneumoniae as a “community bug,” explaining that while it is transmitted among patients in hospitals, it is transmitted more often outside of hospitals, particularly among children in daycare centers.

He said that every year, the pathogen is one of the most prevalent causes of roughly 7 million cases of otitis media, a common ear infection in children, and 500,000 cases of pneumonia in adults and children. Sinusitis and bronchitis often are caused by it as well, he said.

Ballow noted that the combination of the overuse of antibiotics and inadequate infection-control methods, both in hospitals and in daycare centers, account for the rapid rise of resistance for Streptococcus pneumoniae throughout the U.S.

“Children in daycare centers share their germs,” he said. “They share them on their toys, their clothes, their fingers.”

The problem is compounded, he explained, when a child who has a mild ear infection is treated with antibiotics.

“Antibiotic use propagates the problem,” Ballow said. “We’re a society that thinks that for every ailment, there’s a pill. You have a sick child, you expect to be able to go to the doctor and get medicine. We grew up in the antibiotic era and we have come to expect it. But very often, the cause of the ear infection is viral, not bacterial, and in that case, you don’t need an antibiotic.”

For many ear infections, Ballow said, adequate treatment could include giving the child an over-the-counter pain-relief medicine, using cold compresses on the ear and keeping the child home, as well as following any instructions from the child’s doctor.

In most cases, he said, an antibiotic should be prescribed only if the symptoms change or persist.

The study, funded by Rhone-Poulenc/Rorer, also demonstrated that sparfloxacin, a new drug developed by the company, shows excellent activity against resistant bacteria, including those that are highly resistant. Ballow cautioned, however, that due to the potential for cartilage toxicity, the drug cannot be administered to children or pregnant women.