Antibiotic-resistant infections have become significant threats to citizens of CONNECTICUT:
Drug-resistant Staphylococcus aureus:
- Although primarily affecting ill people in hospitals, Methicillin-resistant Staphylococcus aureus
(MRSA), a drug-resistant bacteria, are infecting a growing number of
people in the community and outside hospitals, including healthy
athletes and children. A recent study in the Journal of the American Medical Association
estimates that 94,000 people have invasive MRSA and that it kills
nearly 19,000 annually in the United States – more deaths than those
caused by emphysema, HIV/AIDS, Parkinson’s disease, and homicide.2
- Hospitalizations for or complicated by MRSA cost nearly double that
for non-MRSA stays – $14,000 for MRSA stays compared with $7,600 for
non-MRSA stays. The average length of stay in the hospital for a
patient with MRSA infection was more than double that for non-MRSA stays
– 10.0 days versus 4.6 days.3
With the spread of MRSA, vancomycin has been increasingly used to control these infections. Vancomycin-intermediate S. aureus
(VISA) is the first step toward developing complete resistance to
vancomycin and was first recognized in Japan in 1996. Since that time,
VISA infections have been recognized in several countries, including the
United States, with 16 cases reported as of September 2006. In 2004,
the Connecticut Department of Public Health was notified of a case of
VISA infection in a hospitalized Connecticut resident. This is the first
confirmed VISA infection in a Connecticut resident and likely
represents the tip of the iceberg.4 There have been three additional VISA cases since then in Connecticut (two in 2008 and one in 2009).
Drug-resistant “gram negative” bacterial infections:
- Serious and life-threatening infections due to antibiotic resistant
“gram negative” bacteria are on the rise across the United States. Gram
negative bacteria primarily are differentiated from gram positive
bacteria, like MRSA, by a cell wall that is particularly adept at
preventing antibiotics from entering the bacteria. These infections,
primarily acquired in hospitals and long term care settings, are
extremely difficult to treat and cause significant numbers of illnesses
and deaths. Bacteria in this group include: Escherichia coli (E.
coli), Klebsiella pneumonia, Pseudomonas aeruginosa, and Acinetobacter.
- In March 2009, CDC published guidelines for detection and control of
E. coli and Klebsiella species with increasing resistance to a subclass
of antibacterial drugs known as carbapenems. Carbapenems are among the
most potent antibiotics currently available and are often considered
the “last line of defense” in the treatment of antibiotic resistant
bacteria. Studies have shown that the mortality rate from infections
caused by carbapenem resistant Klebsiella species is roughly 40%. CDC
described this problem as “another in a series of worrisome public
health developments regarding antimicrobial resistance among
gram-negative bacteria [that] underscores the immediate need for
aggressive detection and control strategies.”5
- Noteworthy, these organisms are difficult to detect with the
automated testing systems currently used in most hospital laboratories.6
- Of critical importance, there are few to no approved antibacterial
drugs currently available to treat many gram negative bacterial
infections and few to no new drugs in the pipeline; drug discovery in
this area is extremely difficult due to challenges in overcoming the
gram negative bacteria’s cell wall.
Other antimicrobial resistance issues:
- Clostridium difficile (C. diff) is a potentially
serious infection in hospitals in the U.S. and abroad that can lead to
severe diarrhea, ruptured colons, perforated bowels, kidney failure,
blood poisoning and death. It is a common cause of
antibiotic-associated diarrhea, accounting for 15-25% of all episodes.
CDC estimates there are 500,000 cases of C. diff infection
annually in the U.S., contributing to between 15,000 and 30,000 deaths.
Elderly hospitalized patients are at especially high risk and mortality
in these patients may exceed 10%. The disease is very difficult to
treat and recurs in at least 20% of cases, even when treated
appropriately.
- In Connecticut, community onset C. diff was added to the
list of diseases reportable to the state health department in 2006. In
2006, 110 cases were identified among Connecticut residents, including 4
deaths. In 2007, 128 cases were reported, with 5 deaths; and in 2008,
113 cases with 4 deaths.7
- During 2008, 494 cases of salmonellosis were reported to the Connecticut Department of Public Health.8 Salmonella
species cause an estimated 1.4 million infections, 15,000
hospitalizations, and 400 deaths annually in the United States. CDC
conducts antimicrobial susceptibility testing on a variety of foodborne
pathogens, including Salmonella species. Fluoroquinolones
(e.g., ciprofloxacin) and third generation cephalosporins (e.g.,
ceftriaxone) are commonly used to treat severe infections caused by Salmonella,
but the bacteria are becoming increasingly resistant to these drugs.
National data demonstrate slowly increasing antimicrobial resistance in Salmonella.9 There have been outbreaks of Salmonella that are resistant to as many as five different antibiotic classes.
Public health laboratory capacity:
A key factor in Connecticut’s ability to detect, monitor and control
antimicrobial resistance is its public health laboratory capacity.
Approximately only half of state public health labs can provide some
basic resistance testing. There has been limited funding in the past
for antibiotic resistance education programs and surveillance, and even
this limited funding is on the decrease. With adequate funding for
staff, supplies and equipment, Connecticut could provide surveillance
testing for antimicrobial resistance in community associated MRSA and Salmonella
isolates. This data could be linked to ongoing DNA fingerprinting that
identifies outbreaks and clusters of these pathogens to further
characterize emerging resistance patterns.
1 Dr. Fred Tenover, quoted in “The Bacteria Fight Back” Science, July 18, 2008.
2 R. Monina Klevens et al. “Invasive Methicillin-resistant Staphylococcus aureus Infections in the United States,” JAMA, October 17, 2007: 1763-1771.
3 Elixhauser, A. and Steiner, C. Infections with Methicillin-Resistant Staphylococcus aureus (MRSA) in U.S. Hospitals, 1993–2005. HCUP Statistical Brief #35. July 2007. Agency for Healthcare Research and Quality.
4 Connecticut Epidemiologist, Connecticut Department of Public Health, Vol. 27, No. 4, July 2007
5 CDC MMWR “Guidance for Control of Infections with Carbapenem-Resistant or Carbapenemase-Producing Enterobacteriaceae in Acute Care Facilities” March 20, 2009 / Vol. 58 / No. 10
6 K. F. Anderson, et al.; Evaluation of Methods To Identify the Klebsiella pneumoniae Carbapenemase in Enterobacteriaceae; Journal of Clinical Microbiology, August 2007, p. 2723-2725, Vol. 45, No. 8
7 Personal communication, Dr. R. Nelson, Connecticut Department of Public Health.
8 Disease Statistics by county, 2008; Connecticut Department of Health; accessed online at http://www.ct.gov/dph/cwp/view.asp?a=3136&q=388390. September 4, 2009.
9 Connecticut Epidemiologist, Connecticut Department of Public Health, Vol. 25, No. 3, June 2005