By Judith Graham
Tribune staff reporter
Dangerous, drug-resistant bacteria are spreading rapidly in Chicago's poor, urban neighborhoods, posing a growing health risk in crowded public housing and an increasingly alarming public-health challenge, according to research published Monday.
Cook County Jail -- a hot spot for the bacteria, known as MRSA -- appears to be contributing to the infectious menace, as hundreds of inmates cycle in and out of the facility daily. The threat was described Monday in the Archives of Internal Medicine by Chicago researchers who documented a sevenfold increase in patients with MRSA infections at Stroger Hospital's emergency room and Cook County medical clinics between 2000 and 2005.
At greatest risk were African-Americans, people jailed in the last year, and residents of public housing on the Near West Side, the study found. "MRSA is becoming epidemic in the community," warned Dr. Bala Hota, the lead author and assistant professor of infectious diseases at Rush University Medical Center.
MRSA stands for methicillin-resistant staphylococcus aureus, a potentially virulent bacteria that doesn't respond to several antibiotics used to treat common staph infections. People struck by the bug frequently develop painful skin boils or abscesses and, in rare circumstances, deadly pneumonias, blood infections and other life-threatening conditions.
"This is a pandemic in the making and the source of an enormous increased burden of disease across Chicago," said Dr. Robert Daum, a specialist in MRSA and professor of pediatrics at the University of Chicago.
Until the late 1990s, MRSA was found exclusively in hospitals. When Chicago researchers reported finding the bacteria in previously healthy, non-hospitalized children in 1998, they were met with disbelief. But after further investigation, it became clear that a new type of superbug, known as community-associated MRSA, had evolved.
This formidable bacteria, with more potential toxins than hospital-acquired MRSA, is the focus of the Cook County study.
Researchers identified 2,346 patients with staph infections in skin, soft tissue, joints or bones who likely picked up the bacteria in their neighborhoods. Of those, 41 percent had MRSA. All patients were seen in Stroger Hospital or county clinics.
When results were analyzed over time, a stark pattern became evident: the incidence of community-associated MRSA infections climbed dramatically, from 24 cases per 100,000 people in 2000 to 164.2 cases per 100,000 in 2005.
By contrast, data from three major U.S. cities available to date, published in 2005 in the New England Journal of Medicine, uncovered community-associated MRSA rates of 18 to 26 cases per 100,000.
There are more questions than answers about the MRSA strain that's dominant in Chicago, known as USA 300.
"It's unknown why USA 300 is so good at spreading in communities or where it comes from or even how it's transmitted," Hota said. Researchers think the primary mode of transmission is person-to-person contact. More than 2 million people are thought to carry MRSA in their noses without knowing it. Also, the bacteria appear able to live on surfaces such as counter-tops for days if not weeks.
Scientists speculate that an important reservoir of infection might be County Jail, an overcrowded, unsanitary environment where MRSA can easily flourish. The bacteria can be passed between inmates on mattresses, on towels and soap -- which are often shared -- or through other means, experts said.
About 96 percent of skin and soft tissue infections currently identified in jail inmates are caused by community-associated MRSA, according to the University of Chicago's Daum.
With as many as 350 inmates entering and leaving the jail every day, the opportunities for transmitting MRSA in the broader community are enormous. Many of these inmates return to poor neighborhoods and public housing complexes, raising the risk of infection.
In turn, this is the population least likely to get routine health care and most likely to show up ill at county clinics and Stroger Hospital's ER. The situation would seem to call for a vigorous public health response. But for the most part, doctors and hospitals aren't required to report MRSA infections to public health departments in Illinois.
The Chicago Department of Public Health is working on an electronic reporting system for MRSA, but at the earliest it expects that to be up "in one institution" in a year or two, said Dr. Susan Gerber, medical director for communicable diseases. Public health officials are targeting MRSA educational campaigns at medical providers, who are being asked to culture skin infections and prescribe appropriate antibiotics.
Daum called the public health response "woefully inadequate" and said "it's like waving a straw in a hurricane."
"Clearly, there's more we can do," said Michael Vernon, director of communicable disease control for Cook County's Department of Public Health. The new Cook County research will focus attention on measures that should be undertaken in housing projects and at the jail, he predicted. "What I'd like to see is jail officials, public health officials, and researchers get together and come up with a plan to institute surveillance and control measures," Vernon said.
The findings evident in Chicago are occurring nationwide. Last August, researchers reported in the New England Journal of Medicine that community-associated MRSA has become the most common cause of skin and soft tissue infections in emergency rooms in 11 cities.
A separate report, in the March 2006 issue of the Annals of Internal Medicine, found that community-obtained MRSA accounted for the majority of staph-related skin infections in Atlanta's public hospital ER and its clinics. It's not just that patients are walking into clinics or ERs with the bacteria; the settings themselves are harboring the superbug.
Last September, Johns Hopkins Hospital found that patient exam tables, countertops, computer keyboards, and patient chairs in a busy AIDS clinic tested positive for MRSA, posing "a greater potential risk to staff and patient safety than previously thought," according to a statement from the institution.
The study calls for "increased vigilance" in hygiene and infection-control practices in hospital outpatient settings, said Dr. Cecilia Johnston, a specialist in infectious disease who led the investigation at Johns Hopkins.
By Judith Graham