A look at current MRSA rates in the Midwest: Are they increasing or decreasing?

By Michael Aanes

North Dakota State University

Abstract: Methicillin-resistant Staphylococcus Aureus (MRSA) have been a significant problem in hospitals worldwide. Doctors became aware of MRSA in the 1960’s but it was relatively rare. It remained a relatively minor problem through the 1970s but started to increase during the 1980’s. In the 1990’s MRSA cases exploded during an epidemic in the United Kingdom. This sparked my interest in learning more about the MRSA rates in the Midwest and to look at if they were increasing or decreasing. My research focused on a literature review of current research on the increase or decrease of MRSA rates in different geographical regions, populations and the differences in Community Acquired (CA) or Hospital Acquired (HA) MRSA rates, as well as obtaining current information from the North Dakota and Minnesota Departments of Health. Through this research I was able to make a determination of what is happening to the MRSA rates in the Midwest over the last decade.

Introduction

As an employee at an inpatient chemical dependency facility in Fergus Falls, MN, I would occasionally run into patients that would have medical complications including MRSA. However, MRSA rates were never consistent, but when there was a patient with MRSA it was more than likely we had another. This raised significant questions as to whether MRSA rates were increasing or decreasing in.

A number of hospitals and state health departments have also raised this question and have done significant research into finding an answer to that question as well. For years, state health departments have kept a log of reported MRSA rates and hospitals have introduced measures to help reduce to the rates of MRSA in their hospital. Additionally, some studies have reflected an increase or decrease in MRSA rates among specific populations but did not indicate how this was reflected in overall MRSA rates reported among the study’s demographical region. Information provided by the Minnesota Department of Health and the North Dakota Department of Health provides enough data to draw a clear picture of variation in MRSA rates in the Midwest.

Methods

For my research study I conducted a literature review of medical journals and articles that will help provide information on what MRSA rates are doing. I read a number of different articles and chose which ones I felt would provide the best information for this study. Additionally, I was able to obtain rates on reported MRSA cases through the decade from the Minnesota Department of Health and North Dakota Department of Health. I also provided a questionnaire to the MDH and NDDH that helped me identify the current MRSA rates reported in 2010 so far. Through the research articles and the statistical data I obtained, I was able to start to look at the differences in the reported MRSA rates from various geographical regions and draw conclusions as to what MRSA rates were doing within the Midwest, specifically Minnesota and North Dakota. The primary information to be used in this study is the information provided from the two state health departments and the remaining information is to be used to look at the differences between the reported MRSA rates from various geographical locations and the reported MRSA rates reported within the states of Minnesota and North Dakota. A respect to the limitations of data provided from an individual study site against a state wide report must be made.

Results

The table below is indicative to the reported MRSA cases from the Minnesota Department of Health. Information not included in the data below is the reported MRSA cases that were unclassifiable as CA or HA. Additional limited data was provided on the number of MRSA cases reported so far in 2010, but from only Hennepin and Ramsey counties. The information reported below did not provide any additional demographical information such as age or gender. However, information on 2010 cases indicates that males generally see a high incidence of MRSA, 21.2% vs. 13.2%. Additionally the 2009 MRSA rates indicate that greater than 50% were in patients age 60 and up and they indicate the findings for 2010 so far are similar. Note that data for 2006 was inconclusive (Minesota Department of Health, 2003-2010).

Table 1:

Year	MRSA Cases	HA-MRSA	CA-MRSA
2003	1817	81%	18%
2004	2411	77%	21%
2005	2955	64%	34%
2006	N/A	N/A	N/A
2007	3495	47%	50%
2008	3605	45%	53%
2009	3401	42%	56%

The second table indicates the reported MRSA rates from the North Dakota Department of Health. The data provided did not distinguish among different demographic information such as gender or age similar to the information provided from the Minnesota Department of Health, with the exceptions to the reported rates for 2009 and 2010. In 2009 63 of the reported cases were male and 40 were among female patients with 1 case where gender was not reported.

Table 2:

Year	MRSA Cases	Rate per 100,000
2000	15	2.3
2001	46	7.2
2002	537	83.6
2003	1342	209
2004	1550	241.4
2005	1566	243.8
2006	1880	292.7
2007	412	64.2
2008	79	12.3
2009	104	16.9
2010*	81	N/A

*Information provided is provisional and data has not been evaluated for publication as the true number of cases of MRSA from 01/01/2010 to 11/19/2010.

The 3rd table indicates the number of cases reported by age for 2009 and 2010.

Table 3:

Age Group	2009	2010*
0 to 9	0	0
10 to 19	2	6
20 to 29	3	4
30 to 39	12	6
40 to 49	11	7
50 to 59	9	13
60 to 69	10	16
70 to 79	24	10
80+	33	18

*Information provided is provisional and data has not been evaluated for publication as the true number of cases of MRSA from 01/01/2010 to 11/19/2010.

In one study conducted in Evanston, IL, at Evanston Northwestern Healthcare, a three-hospital facility, they tested 3334 patients from Sept 04 to Aug 05 and found that 277 of those tested were positive for MRSA. It did not distinguish from CA or HA MRSA. This represented 8.3% of all tested. From Sept 05 to April 07, they increased their study to 62,035 patients and found that 3,926 were positive for MRSA, 6.3% (Robicsek, et al., 2008).

In the next study conducted at sentinel sites throughout rural community based hospitals in Utah and Idaho found that in 2003, there were 799 reported cases of MRSA. Again, it was not distinguished which were HA or CA (Stevenson, Searle, Stoddard, & Samore, 2005).

Another study conducted surveillance from July 2004 to December 2005 at nine sites. That study discovered that of the nine sites, there was a total of 8987 reported MRSA cases. Of those 8987, 85% were HA MRSA, 13.7% were CA MRSA and 1.3% could not be classified. This study indicated that MRSA was highest among patients 65 years of age or older and affected mostly males (Klevens, et al., 2007).

One study addressed the MRSA rates reported in patients infected with HIV. This study focused on CA MRSA and discovered a 17 fold increase in reported MRSA cases between 2003 and 2005. Specific data was unavailable (Kaye, 2006).

Another study focusing on a specific demographic looked at pregnant women admitted to MetroHealth Medical Center in Cleveland Ohio for a cesarean section. All admissions occurred in April 2005 thru March 2006. Of the 104 women enrolled, data was available on 96. Of those 96 patients, 2 were positive for MRSA. The study focused on CA MRSA (Beigi & Hanrahan, 2007).

The next study focusing on Metropolitan area hospitals indicated 21.503 invasive MRSA infections from years 2005 to 2008. Geographical information in this study was limited as to how many and where the hospitals participating in the study were, as well as the individual reported cases each year. The study did indicate that 17,508 (81.4%) were HA MRSA. The study indicated that the individual results from each year indicated a decrease of 9.4% per year from 2005 to 2008 (JAMA and Archieves Journals, 2010).

A final study conducted in 2000 of 12 sentinel hospitals in Minnesota identified a total of 738 CA MRSA infections from January 1, 2000 until December 31, 2003. It did not identify the individual cases for each year the study was conducted.

Discussion

The information I obtained provided significant information into looking at what MRSA rates are doing. Table 1 shows an overall increase in MRSA rates between 2003 and 2008 with a slight decline in 2009. The data collected from 2010 did not provide additional information into this argument. The information from ND indicates that MRSA rates were on a steady increase but took a significant decline after 2006. Information as to why this sudden decline occurred was not available.

In comparing much of the other reported rates; it is hard to draw any significant conclusions. Much of the data provided was on smaller demographical regions and many of the studies did not indicate the MRSA rates for the individual years over which the study was conducted. However, some of the studies such as the study in Idaho and Utah indicate that rural communities in those two states would have fewer MRSA cases than reported cases in Minnesota and North Dakota combined, making it difficult to make an appropriate comparison of the MRSA rates. It is important to note that this study was in a rural setting where the data from the MDH and NDDH indicate a whole state wide report of MRSA cases.

A final conclusion cannot be made without further study; however a preliminary conclusion can be made based on the information from the reported cases from the NDDH that MRSA cases are on the decline. However, the decline in Minnesota in 2009 appears to be minimal and without the complete 2010 data, a solid conclusion cannot be made as it appears that overall, MRSA rates in Minnesota have been on the rise over the last decade. Additionally, without further research into specific demographics, comparison data from certain populations cannot be made. It is fair to assume that individual regions will vary in any increases or decreases in reported MRSA rates as hospitals and health departments continue to address the MRSA concerns.

Bibliography

Beigi, R., & Hanrahan, J. (2007). Staphylococcus aureus and MRSA Colonization Rates Among Gravidas Admitted to Labor and Delivery: A Pilot Study. Infectious Diseases in Obstetrics and Gynecology , 1-4.

Buck, J. M., Como-Sabetti, K., Harriman, K. H., Danila, R. N., Boxrud, D. J., Glennen, A., et al. (2005, October). Community-associated Methicillin-resistant Staphylococcus aureus, Minnesota, 2000-2003. Emerging Infectious Diseases , pp. 1532-1538.

JAMA and Archieves Journals. (2010, August 12). Rate of Health Care Associated MRSA Infections Decreasing, Study Finds. Retrieved October 10, 2010, from Science Daily: www.sciencedaily.com/releases/2010/08/100910163447.htm

Johns Hopkins Medical Institutions. (2010, March 26). Community-Acquired MRSA Becoming More Common in Pediatric ICU Patients. Retrieved October 10, 2010, from Science Daily: www.sciencedaily.com/releases/2010/03/100326101321.htm

Kaye, D. (2006). Community-Acquired MRSA among HIV-Infected Patients Rapidly Rising. Clinical Infectious Diseases , 43.

Klevens, R. M., Morrison, M. A., Nadle, J., Petit, S., Gershman, K., Ray, S., et al. (2007, October 17). nvasive Methicillin-Resistant Staphylococcus aureus Infections in the United States. The Journal of the American Medical Association , 298 (15), pp. 1763-1771.

Minesota Department of Health. (2003-2010). Methicillin-Ressitant Staphylococcus aureus (MRSA), 2003-2010. St. Paul: Minnesota Department of Health Infectious Disease Epidemiology, Prevention and Control Divison.

North Dakota Department of Health. (2010). Methcillin-resistant Staphylococcus aureus. Retrieved October 7, 2010, from North Dakota Department of Health Disease Control: www.ndhealth.gov/disease/info/mrsa.aspx

Robicsek, A., Beaumont, J. L., Paule, S. M., Hacek, D. M., Thomson Jr, R. B., Kaul, K. L., et al. (2008). Universal Surveillance for Methicillin-Resistant Staphylococcus aureus in 3 Affiliated Hospitals. Annals of Internal Medicine, 148 (6), 409-418.

Stevenson, K. B., Searle, K., Stoddard, G. J., & Samore, M. H. (2005). Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant Enterococci in Rural Communities, Western United States. Emerging INfectious Diseases , 11 (6), 895-903.

If you would like to see previous comments or leave comments about this website, click on the comment button below.