MIAMI BEACH – Think globally but track locally when it comes to antimicrobial resistance.
"We want to know what is going on nationally and worldwide in terms of resistance, but we really have to understand, and have down pat, what is going on in our own hospitals," said Aida E. Casiano-Colon, Ph.D., a microbiologist at a large regional laboratory in South Florida.
Awareness and collaboration among clinicians are particularly important when it comes to combating multidrug-resistant organisms (MDROs), Dr. Casiano-Colon said. "MDRO varies geographically and by health care setting. Larger hospitals usually have more resistance." Rates also vary by unit within a hospital, she said.
As clinical microbiology director at Integrated Regional Laboratories in Fort Lauderdale, Dr. Casiano-Colon has access to about 790,000 cultures each year from 13 hospitals and several nursing homes in South Florida, as well as from a national network of correctional facilities.
"We really have to understand, and have down pat, what is going on in our own hospitals."
"First the good news: The gram-positive organisms are actually showing a favorable trend. Antimicrobial resistance is very stable or improving," Dr. Casiano-Colon said at the Florida Antimicrobial Stewardship Symposium sponsored by the University of Miami.
In addition, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) "is actually starting to drop." MRSA prevalence was 62% in 2011 (based on approximately 42,000 S. aureus isolates from 12 South Florida hospitals). This represents a 7.5% drop since 2006. Put another way, there was a 22% decline in MRSA rates per 1,000 adjusted patient-days, from 4.5 in 2006 to 3.5 in 2011 (based on almost 25,000 isolates). Compulsive hand hygiene, use of active surveillance cultures, barrier precautions, and other interventions continue to decrease the MRSA rate, she said.
Annual rates of MRSA bacteremia also continue to steadily decrease. The 2011 rate of 2.9/10,000 adjusted patient-days reveals a 34% drop in the last 5 years. However, MRSA "is still a very significant pathogen. All the other MDROs that cause bacteremia pale in comparison in terms of the rate of bloodstream infections," Dr. Casiano-Colon said.
"We are not really seeing a lot of vancomycin-resistant S. aureus, which is also very good news," she added.
The bad news is "we continue to detect escalating resistance in gram-negative organisms overall, especially ESBL [extended-spectrum beta-lactamase] bacteremia, carbapenem-resistant enterics, and Acinetobacter."
For example, the rate of ESBL bloodstream infections jumped "a very alarming" 333% from 0.6/10,000 patient days in 2008 to 2.6/10,000 in 2010.
Rates of all ESBL infections (including respiratory and urinary tract infections) are also showing an alarming increase, to a rate of 1.2/1,000 adjusted patient-days from 0.48/10,000 in 2007, Dr. Casiano-Colon said.
Resistant strains of carbapenem-resistant Enterobacteriaceae are another growing concern. Rates increased from 0.007 in 2008 to 0.03 in 2011. "These organisms cause severe infections among hospital patients and residents of long-term care facilities," she said.