Program Schedule

Emergence of Shigellosis in Males ≥13 Years Philadelphia, 20082013

Session: Poster Abstract Session: Public Health
Saturday, October 11, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
Background: In recent years in Philadelphia, shigellosis has shifted from a disease primarily affecting children and women of childbearing age to one that more commonly affects males ≥13 years of age.  Studies of similar shifts in other U.S. cities have concluded that increased incidence among adult males may result from outbreaks among men who have sex with men (MSM).  Antibiotic resistance among Shigella species is an additional emerging health concern.

Methods: Surveillance data from all nontravel-related culture-confirmed cases of shigellosis among Philadelphia residents aged 13 years or older from 2008–2013 were analyzed.  Susceptibility data for antibiotics including ampicillin, trimethoprim/sulfamethoxazole (TMP-SMZ), and ciprofloxacin was also collected. Trends in incidence over time and across gender, and patterns of antimicrobial resistance were assessed using chi-square analysis. 

Results: From 2008–2013, 317 shigellosis cases were identified.  The proportion of cases among males increased from 28.6% in 2008 to 83.8% in 2013 (p<0.0001).  The proportion of cases exhibiting resistance to one or more antibiotics increased from 44.4% to 91.2% (p<0.0001).  For TMP-SMZ, resistance increased from 44.4% to 65.6% (p=0.0046). Among males, 79.0% of Shigella specimens tested for antibiotic susceptibility exhibited intermediate or full resistance to at least one antibiotic, compared to 35.8% of specimens from females (p<0.0001).  Among males, 61.1% of specimens tested for TMP-SMZ susceptibility displayed intermediate or full resistance, compared to 33.9% among females (p =0.0006).  A non-significant increase in ampicillin resistance was observed among males (77.4%) relative to females (63.6%). Of the 75 cases reported from males during 2011–2013, 15 (20%) self-identified as MSM. 

Conclusion: The proportion of males aged ≥13 years reported with shigellosis increased during 2008–2013 in Philadelphia.  This gender disparity could indicate increasing rates of infection among MSM.  Cases among males displayed greater antibiotic resistance than those among females.  These findings suggest a need to further characterize risk factors associated with these trends and to develop appropriate interventions among males ≥13 years.

Lauren Finn, MPH1,2, Yvette Khachadourian, MPH1, Caroline C. Johnson, MD1 and Ami S. Patel, PhD1,3, (1)Philadelphia Department of Public Health, Philadelphia, PA, (2)CDC/CSTE Applied Epidemiology Fellow, Philadelphia, PA, (3)Centers for Disease Control and Prevention, Philadelphia, PA


L. Finn, None

Y. Khachadourian, None

C. C. Johnson, None

A. S. Patel, None

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