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Summer Peaks in the Incidences of Gram-Negative Bacterial Infection Among Hospitalized Patients

  • Eli N. Perencevich (a1) (a2), Jessina C. McGregor (a3), Michelle Shardell (a2), Jon P. Furuno (a2), Anthony D. Harris (a2), J. Glenn Morris (a4), David N. Fisman (a5) and Judith A. Johnson (a4)...

Abstract

Objective.

Recognition of seasonal trends in hospital infections may improve diagnosis, use of empirical therapy, and infection prevention interventions. There are very few data available regarding the seasonal variability of these infections. We quantified the seasonal variation in the incidences of hospital infection caused by common bacterial pathogens and estimated the association between temperature changes and infection rates.

Methods.

A cohort of all adult patients admitted to the University of Maryland Medical Center during the period from 1998 through 2005 was analyzed. Time-series analyses were used to estimate the association of the number of infections per month caused by Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Staphylococcus aureus, and enterococci with season and temperature, while controlling for long-term trends.

Results.

There were 218,594 admissions to the index hospital, and analysis of 26,624 unique clinical cultures that grew the organisms of interest identified increases in the mean monthly rates of infection caused by P. aeruginosa (28% of isolates recovered; P < .01), E. cloacae (46%; P < .01), E. coli (12%; P < .01), and A. baumannii (21%; P = .06). For each 10°F increase, we observed a 17% increase in the monthly rates of infection caused by P. aeruginosa (P = .01) and A. baumanii (P = .05).

Conclusion.

Significantly higher rates of gram-negative infection were observed during the summer months, compared with other seasons. For some pathogens, higher temperatures were associated with higher infection rates, independent of seasonality. These findings have important implications for infection prevention, such as enhanced surveillance during the warmer months, and for choice of empirical antimicrobial therapy among hospitalized adults. Future, quasi-experimental investigations of gram-negative infection prevention initiatives should control for seasonal variation.

Copyright

Corresponding author

Veterans Affairs Maryland Health Care System, 100 N. Greene St., Lower Level, Baltimore, MD 21202 (eperence@epi.umaryland.edu)

References

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1. Harris, AD, Bradham, DD, Baumgarten, M, Zuckerman, IH, Fink, JC, Perencevich, EN. The use and interpretation of quasi-experimental studies in infectious diseases. Clin Infect Dis 2004;38:15861591.
2. Harris, AD, Lautenbach, E, Perencevich, E. A systematic review of quasi-experimental study designs in the fields of infection control and antibiotic resistance. Clin Infect Dis 2005;41:7782.
3. McDonald, LC, Banerjee, SN, Jarvis, WR; Nosocomial Infections Surveillance System. Seasonal variation of Acinetobacter infections: 1987-1996. Clin Infect Dis 1999;29:11331137.
4. Retailliau, HF, Hightower, AW, Dixon, RE, Allen, JR. Acinetobacter calcoaceticus: a nosocomial pathogen with an unusual seasonal pattern. J Infect Dis 1979;139:371375.
5. Furuno, JP, McGregor, JC, Harris, AD, et al. Identifying groups at high risk for carriage of antibiotic-resistant bacteria. Arch Intern Med 2006;166:580585.
6. Harris, AD, Perencevich, E, Roghmann, MC, Morris, G, Kaye, KS, Johnson, JA. Risk factors for piperacillin-tazobactam-resistant Pseudomonas aeruginosa among hospitalized patients. Antimicrob Agents Chemother 2002;46:854858.
7. Harris, AD, Samore, MH, Lipsitch, M, Kaye, KS, Perencevich, E, Carmeli, Y. Control-group selection importance in studies of antimicrobial resistance: examples applied to Pseudomonas aeruginosa, enterococci, and Escherichia coli . Clin Infect Dis 2002;34:15581563.
8. Kim, PW, Harris, AD, Roghmann, MC, Morris, JG Jr, Strinivasan, A, Perencevich, EN. Epidemiological risk factors for isolation of ceftriaxone-resistant versus -susceptible Citrobacter freundii in hospitalized patients. Antimicrob Agents Chemother 2003;47:28822887.
9. NCCLS. Analysis and presentation of cumulative susceptibility test data: approved guideline. NCCLS document. Wayne, PA: NCCLS, 2002:M39A.
10. National Weather Service. Eastern Region Headquarters. Available at: http://www.erh.noaa.gov/. Accessed October 4, 2006.
11. Fisman, DN, Lim, S, Wellenius, GA, et al. It's not the heat, it's the humidity: wet weather increases legionellosis risk in the greater Philadelphia metropolitan area. J Infect Dis 2005;192:20662073.
12. McCullagh, P, Nelder, JA. Generalized Linear Models. 2nd ed. Boca Raton, FL: Chapman & Hall/CRC Press; 1989.
13. de Boor, C. A Practical Guide to Splines. New York: Springer; 1978.
14. Kelsall, JE, Samet, JM, Zeger, SL, Xu, J. Air pollution and mortality in Philadelphia, 1974-1988. Am J Epidemiol 1997;146:750762.
15. R: a language and environment for statistical computing [computer program]. Version 2.4.0. Vienna; 2004.
16. Naumova, EN. Mystery of seasonality: getting the rhythm of nature. J Public Health Policy 2006;27:212.
17. Dowell, SF, Ho, MS. Seasonality of infectious diseases and severe acute respiratory syndrome—what we don't know can hurt us. Lancet Infect Dis 2004;4:704708.
18. Smith, TL, Pullen, GT, Crouse, V, Rosenberg, J, Jarvis, WR. Bloodstream infections in pediatric oncology outpatients: a new healthcare systems challenge. Infect Control Hosp Epidemiol 2002;23:239243.
19. Hawke, M, Wong, J, Krajden, S. Clinical and microbiological features of otitis externa. J Otolaryngol 1984;13:289295.
20. van Asperen, IA, de Rover, CM, Schijven, JF, et al. Risk of otitis externa after swimming in recreational fresh water lakes containing Pseudomonas aeruginosa . BMJ 1995;311:14071410.
21. Barben, J, Hafen, G, Schmid, J. Pseudomonas aeruginosa in public swimming pools and bathroom water of patients with cystic fibrosis. J Cyst Fibros 2005;4:227231.
22. Ogden, ID, MacRae, M, Strachan, NJC. Is the prevalence and shedding concentrations of E. coli O157 in beef cattle in Scotland seasonal? FEMS Microbiol Lett 2004;233:297300.
23. Boyce, TG, Swerdlow, DL, Griffin, PM. Escherichia coli O157:H7 and the hemolytic-uremic syndrome. N Engl J Med 1995;333:364368.
24. Scholes, D, Hooton, TM, Roberts, PL, Stapleton, AE, Gupta, K, Stamm, WE. Risk factors for recurrent urinary tract infection in young women. J Infect Dis 2000;182:11771182.
25. Fortenberry, JD, Orr, DP, Zimet, GD, Blythe, MJ. Weekly and seasonal variation in sexual behaviors among adolescent women with sexually transmitted diseases. J Adolesc Health 1997;20:420425.
26. Rojansky, N, Brzezinski, A, Schenker, JG. Seasonality in human reproduction: an update. Hum Reprod 1992;7:735745.
27. Haines, A, Patz, JA. Health effects of climate change. JAMA 2004;291:99103.

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