Nationwide Dissemination of Multiply Resistant Shigella
sonnei Following a Common-Source Outbreak
In early July 1987, an outbreak of multiply resistant Shigella
sonnei gastroenteritis occurred among persons who attended the
annual
Rainbow Family gathering in North Carolina (1). Since that time,
four
clusters of gastroenteritis due to multiply resistant S. sonnei
have
been reported among persons who had no apparent contact with
gathering
attendees.
Preliminary results from a survey of gathering attendees showed
that 157 (58%) of the 270 respondents experienced acute diarrheal
illness. This finding is consistent with previous estimates of a
50%
or greater attack rate of acute gastroenteritis among the 12,000
attendees (1). Seventy-five attendees from 26 states* and 14
contacts
of these persons who had not attended the gathering have had
culture-confirmed infection. The S. sonnei isolates from these
patients are resistant to ampicillin, tetracycline, and
trimethoprim-sulfamethoxazole--the antibiotics usually used to
treat
shigellosis.
In July, August, and September, clusters of multiply resistant
S.
sonnei infection occurred in Missouri and Pennsylvania. Isolates
from
these cases showed an antimicrobial resistance pattern similar to
that
of the strain involved in the North Carolina outbreak. Two small
clusters were reported from Missouri. A third cluster occurred
among
patrons and employees of a Pennsylvania restaurant. In a fourth
cluster, which has been epidemiologically linked to the third,
residents and staff of a nursing home in the same Pennsylvania town
became ill.
Reported by: JN MacCormack, MD, MPH, State Epidemiologist, North
Carolina Dept of Human Resources. RH Hutcheson, MD, State
Epidemiologist, Tennessee Dept of Health and Environment. HD
Donnell
Jr, MD, MPH, State Epidemiologist, Missouri Dept of Health. C
Diehl, M
Hardin, R David, MD, Acting State Epidemiologist, Pennsylvania Dept
of
Health. Enteric Diseases Br, Div of Bacterial Diseases, Center for
Infectious Diseases; Div of Field Svcs, Epidemiology Program
Office,
CDC.
Editorial Note
Editorial Note: In a national survey of Shigella isolates
conducted
in 1985 and 1986, approximately 4% of isolates from S. sonnei
infections acquired in the United States were resistant to
trimethoprim-sulfamethoxazole. None had the same antimicrobial
resistance pattern as the North Carolina outbreak strain. The
occurrence of these four clusters of infection with multiply
resistant
S. sonnei underscores the need for sensitivity testing to guide in
selecting appropriate antimicrobial therapy. Such testing also
permits
early identification and prompt reporting of multiply resistant
strains to public health authorities so further transmission can be
prevented.
Further spread of this resistant strain will likely limit the
effectiveness of the usual antimicrobial agents for treating
shigellosis. Infections that are caused by this multiply resistant
Shigella and that require antimicrobial therapy can be treated with
nalidixic acid or norfloxacin. Although studies in other countries
suggest that both nalidixic acid and norfloxacin are effective for
the
treatment of shigellosis (2,3), it is important to note that
neither
nalidixic acid nor norfloxacin has been approved by the Food and
Drug
Administration (FDA) for the treatment of bacterial
gastroenteritis.
Both nalidixic acid and norfloxacin are quinolones, and care should
be
exercised in prescribing either one for children because of
experimental evidence that quinolones can cause arthropathy in
young
animals (4,5). No such lesions have been reported to the FDA in
association with nalidixic acid therapy in humans. Life-threatening
infections are rare with S. sonnei but could be treated with
gentamicin or chloramphenicol, to which the outbreak strain is
sensitive.
Basic hygiene and sanitary precautions remain the cornerstones
of
control measures for shigellosis outbreaks, including those due to
multiply resistant strains (6). Vigorous emphasis on handwashing
with
soap after defecation and before eating has been shown to reduce
secondary transmission of shigellosis (7).
Comparison of norfloxacin and nalidixic acid for treatment
of
dysentery caused by Shigella dysenteriae type 1 in adults.
Antimicrob Agents and Chemother 1986;29:883-6.
DuPont HL, Corrado ML, Sabbaj J. Use of norfloxacin in the
treatment of acute diarrheal disease. Am J Med 1987;82(suppl
6B):79-83.
Schlduter G. Ciprofloxacin: review of potential toxicologic
effects. Am J Med 1987;82 (suppl 4A):91-3.
Corrado ML, Struble WE, Chennekatu P, Hoagland V, Sabbaj J.
Norfloxacin: review of safety studies. Am J Med 1987;82(suppl
6B):22-6.
CDC. Multiply resistant shigellosis in a day care
center--Texas.
MMWR 1986;35:753-5.
Khan MU. Interruption of shigellosis by hand washing. Trans R
Soc
Trop Med Hyg 1982;76:164-8.
*California, Colorado, Connecticut, Florida, Georgia, Illinois,
Iowa,
Maryland, Massachusetts, Michigan, Missouri, New Hampshire, New
Jersey, New Mexico, New York, North Carolina, Ohio, Pennsylvania,
Rhode Island, Tennessee, Texas, Utah, Vermont, Virginia, West
Virginia, and Wisconsin.
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