Notable Outbreaks Underscore Importance of Infection Preventionists, Epidemiologists

Arjun Srinivasan, MD, from the Division of Healthcare Quality Promotion at the Centers for Disease Control and Prevention (CDC), points to some of the most influential outbreaks of healthcare-associated infections (HAIs) in the past decade and says that they can impart two important lessons to infection preventionists: "First, they reflect the truly global nature of healthcare delivery and thus of HAIs. It is clear that detection, investigation, and prevention of HAI outbreaks will increasingly require coordination between clinicians and public health agencies regionally and even internationally. We must make investments in our infrastructure for HAI prevention and investigation that will facilitate this cooperation. Finally, there has been much talk in the past decade about the role of healthcare epidemiologists as leaders in HAI prevention, an issue much discussed at this Fifth Decennial International Conference on Healthcare-Associated Infections. However, I believe these outbreaks are as powerful an argument as any for the central role that healthcare epidemiologists must continue to play in controlling HAIs."

In Infection Control & Hospital Epidemiology, Srinivasan details the following notable outbreaks:

1. In 2005, Kazakova et al. published an investigation of methicillin-resistant Staphylococcus aureus (MRSA) infections among professional football players, an investigation led to the initial description of the MRSA clone USA 3000114 as the predominant clone in a variety of MRSA outbreaks. Although transmission of this clone initially was linked primarily to community settings, its discovery has had a major impact on HAIs. The discovery of clone USA 3000114 contributed to an unprecedented level of awareness about MRSA, and healthcare-associated MRSA infections quickly became part of a very public and intense discussion. The surge in interest in MRSA has led to major healthcare initiatives for prevention of MRSA transmission and infection in several countries, some of which have achieved impressive results, and also has helped drive an increasing number of legislative mandates for MRSA screening in the United States.

2. In 2005, McDonald et al. and Loo et al. published reports of outbreaks of Clostridium difficile infections that were associated with unusually high levels of morbidity and mortality. These reports were the initial descriptions of a new strain of C. difficile that has come to be known as the North American pulsed-field gel electrophoresis type 1 (NAP1) strain, or "the epidemic strain." NAP1 strains differ from other C. difficile strains in that they produce higher levels of toxins A and B and a new toxin (binary toxin) and are resistant to fluoroquinolone antibiotics. These factors have likely contributed to the consistent finding that infections with NAP1 strains of C. difficile are associated with more severe outcomes, compared with C. difficile infections with other strains. Description of the NAP1 strain of C. difficile and the resultant increase in the number of cases of infection with this strain in several countries have spurred not only public awareness of C. difficile but also interest and activity in prevention efforts.

3. Outbreaks of infection with carbapenem-resistant Klebsiella pneumoniae (referred to as "KPC [K. pneumoniae carbapenemase]producing organisms") have been reported in both the United States and Israel. These outbreaks have demonstrated the rapid potential for dissemination of KPC-producing organisms in healthcare settings and have also begun to raise public awareness of the public health threat posed by multidrug-resistant gram-negative pathogens, especially awareness of the limited number of drugs available to treat infections with these organisms.

4. In 2004, Kainer et al.11 published the results of an investigation of Clostridium infections that were caused by contaminated human allograft tissues. They determined that "carry-over" of antimicrobials used in the disinfection of the tissues had led to falsenegative culture results in release testing. This outbreak was a true sentinel event in the field of tissue safety, because it highlighted a previously underappreciated public health and patient safety issue. The response to this outbreak has been an excellent example of how outbreaks can lead to important patient safety improvements. Following this investigation, the tissue banking industry took steps to ensure that tissues contaminated with pathogens such as Clostridium species would be discarded and to improve the validation of culture methods for release testing. There has also been increasing support for enhanced regulatory activity in the tissue banking industry, as well as a growing awareness among clinicians of the potential for infections to be transmitted through tissues, which has led to the early identification of other episodes of disease transmission.

5. Issues pertaining to disease transmission through organ transplantation also attained prominence during this decade, and three outbreaks were particularly influential in this area. In 2003, Iwamoto et al. described the transmission of West Nile virus through organ transplantation, and this publication was followed by reports in 2005 and 2006 of organ transplant-associated transmission of rabies virus and lymphocytic choriomeningitis virus. Together, these reports helped galvanize awareness of the potential for disease transmission through organ transplantation and highlighted important safety gaps that are being addressed. They identified our potential vulnerability in identification of organ transplant-associated outbreaks and have led to improvements in communication between transplant centers and recovery organizations. They also have led to important policy discussions about the use of blood vessel conduits, which, if not needed for transplanting an organ from the donor, are often retained and then used in a subsequent procedure. .

6. In 2007, the improper reuse of single-dose vials of propofol by staff at an endoscopy center in Nevada led not only to the transmission of hepatitis C virus to multiple patients but also to the notification of more than 50,000 patients of their potential exposure to bloodborne viruses. The outbreak created a maelstrom of public outrage and legislative scrutiny. However, it was by no means the only instance of simple breaches in injection safety that led to patients being potentially exposed to serious illness. Guh et al. identified 46 such episodes from 1999 through 2009 that involved more than 150,000 patients. Fortunately, the public awareness of injection safety problems that was generated by these outbreaks is driving important efforts to address the problem. These efforts include new educational campaigns (eg, the "One and Only Campaign" in the United States), as well as increased scrutiny of injection practices by state and federal officials and measures taken by the Food and Drug Administration to improve the use of single-dose vials.

Reference: Srinivasan A. Influential Outbreaks of Healthcare-Associated Infections in the Past Decade. Infect Control Hosp Epidemiol 2010;31:S70S72

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