"' "'
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ISSN 0382-232X
Rapport hebdomadalre des
maladies au Canada
Canada Diseases
Weekly Report
Date of publication: 14December1991
Vol. 17·50
Date de publication: 14 decembre 1991
Contenu du present numero:
Contained In this Issue:
Antimicrobial Susceptibilities of Shigella Species Isolated
in Ontario in 1990 . . . • . . . . .
Multiply-Resistant Shige//a sonnei from Recent Outbreaks
in Canada . . . . . . . . . . . . .
Shige//a dysenteriae Type 1 - Guatemala . . . . .
Sensibilite aux antimicrobiens des especes de Shige//a isolees
en Ontario en 1990 . . , . • . . . . . . .
Souches de Shige//a sonnei multi-resistantes dans de recentes eclosions
de cas au Canada . . . . . . . . . . . . . . . . . .
Shigella dysenteriae type 1 - Guatemala . . . . • . . . . . •
Shigellosis is a disease which is recognized as a global problem
with high morbidity in developing countries<l.2>. Antimicrobial
resistant Shigel/a spp. have been found in many parts of the world and
resistant isolates have also been reported in Canada<304>. Antimicrobial
therapy of some cases of shigellosis is indicated for several clinical
and epidemiologic reasons<5•6>. Physicians who· elect not to treat cases
indicate that, in most instances, the disease is self-limiting and
,. ~~latively mild, that post-infection carriage doeS1J1ot extend over a
:g period, and that the use of antibiotics incre~es the ljkelihood of
- 1 increase in the number of multiply-resi!;tant isolates('ll.; R-factor
mediated antimicrobial resistance, well known for the, potential to
spread from strain to strain, plays a major role i J. the development of
resistance inShigel/a species<8>.
La shigellose ~st une maladie qui est reconnue comme un probieme a
l' echelle mondiale et qui est la cause d 'une morbidite elevee dans les pays en
voie de developpement0.2>. On a decouvert des especes de Shigella
antibioresistantes dans de nombreuses regions du monde et l' on a egalement
signale des isolats resistants au Canada <3•4>, Dans certains cas de shigellose, la
therapie antimicrobienne est indiquee pour diverses raisons cliniques et
epidemiologiques(S,6), Les medecins qui decident de ne pas adrninistrer de
medicaments indiquent que, dans la plupart des cas, la maladie est relativement
benigne et guerit spontanement, la periode de portage qui suit l'infectionn'est
pas tres longue et I' usage d' antibiotiques risque de faire augmenter le nombre
d'isolats multi-resistants(?>. La resistance aux antimicrobiens attribuable au
facteur R, dont on conn mt bien la capacire de se transmettre d 'une souche a
une autre, joue un role important dans l' acquisition d 'une resistance parmi les
especes de Shigella cs>.
The purpose of this study was to determine the antimicrobial
susceptibility patterns of isolates of Shigella spp. from Ontario
submitted to the Central Public Health Laboratory in 1990. This
investigation is part of an epidemiologic surveillance of Shigel/a
isolates in Ontario and other provinces in Canada to determine the
incidence of antimicrobial resistance among these organisms. A total
of 598 isolates were examined: 30 S. boydii, 24 S. dysenteriae,
254 S.flexneri, and 290 S. sonnei.
L'objet de la presente etude etait de determiner les profils de sensibilite des
isolats de diverses especes de Shigella de l'Qntario foumies par le Laboratoire
central de sante publique en 1990. La presente enquete fait partie d'une
surveillance epidemiologique d'isolats de Shigella en Ontario et dans d' autres
provinces du Canada qui vise adeterminer dans quelle mesure ces organismes
sont antibioresistants. Au total, 598 isolats ont ere examines : 30 isolats de S.
boydii, 24 de S. dysenteriae, 254 de S.flexneri et 290 de S. sonnei.
Antimicrobial susceptibility testing was performed by the agar
dilution method as outlined by the National Committee of Clinical
Laboratory Standards<9>. The concentrations evaluated in this study
were as follows: ampicillin, chloramphenicol, tetracycline and
trimethoprim, 8 mg/L; gentarnicin, norfloxacin and tobramycin,
4 mg/L; amikacin, 16 mg/L; ciprofloxacin, 1 mg/L; nalidixic acid,
6 mg/L; piperacillin and ticarcillW, 1_6 and 64 mg/L;
sulfamethoxazole, 256 mg/L; cotrimoxazole (trimethoprimsulfamethoxazole), 0.5/9.5 mg/L.
Les epreuves de sensibilite aux antimicrobiens ont ete realisees par la
methode des dilutions sur gelose decrite dans les normes National Committee
of Clinical Laboratory StandardsC9l, Les concentrations evaluees dans la
presente etude etaient les suivantes: ampicilline, chloramphenicol, tetracycline
et trimethoprime, 8 mg/L; gentarnicine, norfloxacine et tobramycine, 4 mg/L;
amikacine, 16 mg/L; ciprofloxacine, 1 mg/L, acide nalidixique, 6 mg/L;
piperacilline et ticarcilline, 16 et 64 mg/L; sulfamethoxazole, 256 mg/L;
cotrimoxazole (trimethoprime-sulfamethoxazole), 0,5/9,5 mg/L.
Overall, 79.6% of isolates were resistant to 1 or more antimicrobial
agents (S. boydii, 90%; S.flexneri, 89%; S. dysenteriae, 15%;
S. sonnei, 71 %). Fifty-two percent of all isolates were resistant to 4 or
more antimicrobial agents. Differences in antimicrobial resistance
patterns among the Shigel/a spp. are shown in Table 1. The percentage
of sulfamethoxazole resistance was highest among S. boydii (76.7%)
and lowest among isolates of S.flexneri (44.5%). Resistance to 2 of
the first-line treatment drugs, ampicillin and tetracycline, was highest
'\ong S. boydii and S.flexneri, 56.7% and 73.3% versus 66.5% and
.3%, respectively. Cotrimoxazole-resistant isolates have increased
Dans l' ensemble, 79 ,6% des isolats etaient resistants aau mo ins 1 agent
antimicrobien (S. boydii, 90%; S.flexneri, 89%; S. dysenteriae, 15%; S.
sonnei, 71 %). En outre, 52% de tous les isolats etaient resistants a4 agents
antimicrobiens OU plus. Les differences dans les profils de resistance aux
antimicrobiens des diverses especes de Shigella sont presentees au Tableau 1.
C'est chez S. boydii qu'on a trouve le pourcentage le plus eleve de resistance
au sulfamethoxazole, soit 76,7%, alors qu'il etait le plus foible parmi les isolats
de S.flexneri (44,5%). La resistance a2 medicaments majeurs, asavoir
I' ampicilline et la tetracycline, etait la plus elevee chez s. boydii et s.flexneri,
soit 56, 7% et 73,3% contre 66,5% et 80,3% respectivement. Le pourcentage
I SOc<lnd Com
Mal Raljtl!al0<1 No. 6670
Health and Welfare
I Coo..rne< de lo dwdilma cias'9 • Ertag!slrament n•
Santa et Bien~tre social
Table 1ffableau 1
Antimicrobial resistance among isolates of Shigel/a species submitted to the Ontario Central Public Health Laboratory in 1990
Resistance aux antimicrobiens d'isolats de certaines especes de Shigel/a sou mises au Laboratoire central de sante publique de
!'Ontario en 1990
Antimicrobial a~ent
Agent anti micro ien
s. b°{odii
(n= 0)
S. dysenteriae
S. flexnerl
. (n=24)
S. sonnei
from a low of 3% reported in 1980 by Bannatyne et al<3> to between
26.7% and 37.6%, representing a 9 to 12-fold increase over the
12-year period of the previous study. It is also noteworthy (Table 1)
that a number of isolates of S.flexMri were resistant to
trimethoprim but not to cotrimoxazole.
des isolats resistants au cotrimoxazole est passe de 3% en 1980, selon les
travaux realises par Bannatyne et ses collaborateurs <3>, a entre 26,7% et
37,6% aujourd'hui, ce qui est un taux entre 9 et 12 fois plµs eleve que celui
qui avait ete signale il y a 12 ans. 11 importe egalement de souligner
(Tableau 1) qu'un certain nombre d'isolats de S.jlexMri avaient acquis
une resistance au trimethoprime mais non au cotrimoxazole.
An interesting finding with B-lactamase antimicrobial agents is
also shown in Table 1. All strains resistant to ampicillin were also
resistant to ticarcillin, but few strains of S. dysenteriae, S.flexMri
and S. boydii were resistant to piperacillin. An investigation is
underway with these strains.
Le Tableau 1 laisse egalement entrevoir un phenomene inreressant en ce
qui conceme les B-lactamines. Toutes les souches qui etaientresistantes a
l'ampicilline etaient egalementresistantes ala ticarcilline, mais peu de
souches des. dysenteriae, s. jlexneri et s. boydii etaient resistantes a la
piperacilline. Des travaux sont actuellement en cours sur ces souches.
Only a small percentage of isolates of S. sonnei (5.2%) were
resistant to chloramphenicol compared to the other 3 species. Many
isolates were multiply resistant showing resistance to all first-line
drugs, i.e., ampicillin, tetracycline and cotrimQxazole. None of the
isolates was resistant to gentamicin, tobramycin, amikljCin,
norfloxacin, ciprofloxacin or nalidixic acid. Clearly, tlj,e need to
monitor the changing trends in the susceptibility to.!liltimicrobials
of Shigella spp. is important. These results frdtn Ontario show that
a significant percentage of isolates of Shigel/ae are resistant to a
number of antimicrobial agents and emphasire the need for prudent
use of antibiotics in the treatment of shigellosis.
Seul un faible pourcentage d'isolats de S. sonnei (5,2%) etaient
resistants au chloramphenicol comparativement aux 3 autres especes. De
nombreux isolats etaient multi-resistants, offrant une resistance a tous les
medicaments majeurs, c'est-a-dire l'ampicilline, la tetracycline et le
cotrimoxazole. Aucun des isolats n' avait acquis une resistance ala
gentamicine, la tobramycine, I' amikacine, la norfloxacine, la ciprofloxacine
OU l 'acide nalidixique. De toute evidence, il importe se suivre l 'evolution
des tendances en ce qui conceme la sensibilire des especes de Shigella aux
antimicrobiens. Les resultats de !'Ontario montrent qu 'un pourcentage
important des isolats de Shigella sont resistants a uncertain nombre
d' agents antimicrobiens et font ressortir la necessite d'utiliser prudemment
les antibiotiques dans le traitement de la shigellose.
Les auteurs tiennent areconnaitre l 'aide apportee a J, Damdar, Services
de soutien microbiologiques, et de S. McLeod, Y. Au Yong, V. Brunins, A.
Chow, H. Dedier, A. Borczyk et G. Riley, Service de bacteriologie
clinique, Laboratoire central de sante publique, Toronto (Ontario).
1. Palchauduri S, Kumar R, Sen D, et al. Molecular Epidemiology of
erift Y/.)~~~~4/ui'fcrnteriae
IJJ!e 1 obtained from an
__'/2__~ :_ lli_
g__a ·-~-).FEMS Lett 1985;30 :187-91.
The author acknowledges the assistance of J. Damdar,
Microbiological Support Services and S. McLeod, Y. AuYong, V.
Brunins, A. Chow, H. Dedier, A. Borczyk, and G. Riley, of Clinical
Bacteriology, Central Public Health Laboratory, To!onto, Ontario.
1. Palchauduri S, Kumar R, Sen D, et al. Molecular epidemiology
ofplasmid patterns in ShigeUa dysenteriae type 1 obtained
from an outbreak in West Bengal (India). FEMS Lett
2. Tiemens KM, Shipley PL, Correia RA, Shields DS, Guerrant
RL. Sulfamethoxazole-trimethoprim-resistant ShigeUaflexneri
in northeastern Brazil. Antimicrob Agents Chemother
3. Bannatyne R, Toma S, Cheung R, Hu G. Resistance to
trimethoprim and other antibiotics in Shigellae isolated in the
province of Ontario. Can J Microbiol 1980;26:1256-8.
4. Harnett N, McLeod S, AuYong Y, Krishnan C. Increasing
incidence of resistance among ShigeUae to trimethoprim.
Lancet 1991;337:622.
5. Chang MJ, Dunkle LM, VanReken K, Anderson D, Wong ML,
Feigin RD. Trimethoprim-sulfamethoxazole compared to
amp_i~i~lin in the treat11_Wnt of shigellosis. Pediatrics
2. Tiemens KM, Shipley PL, Correia RA, Shields DS, Guerrant RL.
Sulfamethoxazole-trimethoprim-resistantShigella ffexneri in
nortbeasternBrazil. Antimicrob Agents Chemother 1984;25 :653-4.
3. Bannatyne R, Toma S, Cheung R, Hu G. Resistance to trimetbQprjm
and other antibiotics in Shigef/ae isolated in the province QfOntario.
Can J Microbiol 1980;26 :1256-8.
4. Hamett N, McLeod S, AuYong Y, Krishnan C. lncreasinf incidence Q.f
resistance among Shigellae to trjmethoprim. Lartcet 199;337 :622.
5. Chang MJ, DunkleLM, VanRekenK, AndersonD, Won~ ML, Feigin
RD. Trimethoprim-sulfmnethoxazole co'{fqred to ampicillin in the
treatment ofshigel/osis. Pediatrics 1977; :726-9.
Pickerin~ LK, Dupont HL, Olarte J. Single-dose tetracycline
therapy for shigellosis in adults. JAMA 1978;239:853-4.
7. Keusch GT. Shigella infections. In: Lambert HP, ed. Clinics in
gastroenterology. Vol 8. Philadelphia: W B Saunders,
8. Datta N, Hughes VM, Nugent ME, Richards H. Plasmids and
transposons and their stability and mutability in bacteria
isolated during an outbreak of hospital infection. Plasmid
1979;2: 182-96.
9. National Committee for Clinical Laboratory, Standards.
Methods/or dilution antimicrobial susceptibility tests for
bacteria that grow aerobically. 2nd ed. Approved Standard.
NCCLS Document M7-A2. Villanova, Pa: NCCLS, 1990.
Source: N Harnett, PhD, Research Scientist, Clinical
Bacteriology Section, Central Public Health Laboratory,
Toronto, Ontario.
6. Pickering LK, Dupont HL, Olarte J. Single-dose tefrqc;ycline the111J2y
for shigeUosis in adults. JAMA 1978;239 :853-4.
7. Keusch GT. Shigella i'(ections. Dans: Lambert HP, ed. Clinics in
gastroenterology. Vol . Philadelphia: W B Saunders, 1979 :645-62.
8. Datta N, Hughes VM, Nugent ME, Richards H. Plasmids and
transposons and their stabilifl and mutqbility in bqcteria isolqted
during an outbreakQ.fhospjtal infection. Plasmid 1979;2 :182-96.
9. National Committee for Clinical Laboratozy Standards. Methods for
dilution antimigrobjal suscentibWty tests for bacteria that grow '
a~robjcally. 2 ed. mry;astandar<l. NCCLS DocumeutM7-A2.
Ytllanoya. Pa: NC_. __ .·
Source: N Harnett, PhD, Chercheur scientijique, Section de bacteriologie
clinique, Laboratoire central de sante publique, Toronto
In recent years, Shigella sonnei has emerged as the most
frequent cause of shigellosis in Canada (H. Liar, National
Reference Centre for Enteric Pathogens, LCDC: personal
communication, 1991). Epidemiologic analyses of outbreaks
caused by this pathogen have been hindered by the lack of suitable
epidemiologic markers for strain differentiation. During a
laboratory investigation of potential markers for S. sonnei, we
determined the antimicrobial susceptibilities of strains associated
with outbreaks in Canada that occurred between 1988 and 1991.
The results of our study have shed new light on several aspects of
antibiotic resistance in this species in Canada.
Au cours des dernieres annees, Shigella sonnei est apparue comme la
cause la plus frequente de shigellose au Canada (H. Liar, Laboratoire
national de reference des pathogenes enteriques, LLCM : communication
personnelle, 1991 ). L' absence de marqueurs epidemiologiques convenables
perrnettant la differenciation des souches a nui aux analyses
epidemiologiques des eclosions causees par ce pathogene. Au cours d'une
etude en laboratoire des marqueurs eventuels de S. sonnei, nous avons
determine la sensibilite aux antimicrobiens de souches associees ades
eclosions survenues au Canada entre 1988et1991. Les resultats de notre
etude ont permis de jeter un regard nouveau sur la resistance aux
antibiotiques de cette espece au Canada.
Bacteria! Strains
Souches bacterlennes
A total of 36 clinical isolates of S. sonnei from 8 recent
outbreaks of shigellosis in Ontario, Alberta and New Brunswick
were examined (fable 1). Five of the outbreaks occurred in Ontario
. and strains from these outbreaks were from the culture collection of
lhe Enteric Reference Laboratory of the Central Publi~Health
Laboratory in Toronto. The remaining strains,were ob.Wned from
the provincial public health laboratories in Ciilgacy, Edmonton and
Saint John. All cultures were identified as S: $,onmii by using
standard laboratory criteria.
On a examine au total 36 isolats cliniques de S. sonnei obtenus !ors de 8
eclosions recentes en Ontario, en Alberta et au Nouveau-Brunswick
(Tableau 1). Cinq de ces eclosions sont survenues en Ontario, et des
souches de ces eclosions provenaient de la collection des cultures du
Laboratoire de reference des maladies enteriques du Laboratoire central de
sante publique aToronto. Les autres souches ont ete obtenues des
laboratoires provinciaux de sante publique aCalgary, Edmonton et
Saint-Jean. Toutes les cultures de S. sonnei ont ete identifiees al'aide de
crireres de laboratoire normalises.
Antibiotic Susceptlblllty Testing
Epreuves de senslblllte aux antlblotlques
Susceptibility testing was performed by using a breakpoint, agar
dilution procedure with Mueller-Hinton agar, as described by the
National Committee for Clinical Laboratory Standards(l>. Agar
On a realise les epreuves de sensibilite en utilisant une methode de
dilutions sur milieu gelose Mueller-Hinton decrite daf!S les National
Committee for Clinical Laboratozy Standards (1), Des boites d'agar
Table 1ffableau 1 ·
Antibiotic SusceptibilitYi of Sh!feella sonnei Strains Associated with Eight Recent Outbreaks in Canada
Sensibil!te aux antibio iques e souches de Shigel/a sonnei associees huit eclosions recentes au Canada
closlon n°
Ontario .,, Ontario
New Brunswick
Year of Isolation
Annee lsolee
No of Isolates Tested
N0re d'isolats testes
Resistance Pattern
Profil de resistance
Amp, Carb, Pip, Tic
Amp, Carb, Tic, Amox/Clav, Caph.
Amp, Carb, Pip, Tic, Amox/Clav, Caph, Smx, Tmp,
Amp, Carb, Pip, Tic, Smx, Tmp, Tmp/Smx
Amp, Carb, Tic, Amox/Clav, Smx, Chier, Tet
Amp, Carb, Pip, Tic, Smx, Tmp, Tmp/Smx, Tet
' Susc -Susceptible to antibiotics tested I Sens. -Sensible aux antibioti~ues essayas: Amri- ampicillin/ampicilline, Carb- carbenicillin/Carbanicilline, Pip- piperacillin/Piperacilline,
Tic- Ticarcillinmcarcilline, Am,ox/Clav-Amoxillin/~lavulanic acid/amox cilline/aciCI!! clavu anique, C~ph - cephalothin/~falotine, SIJ1X -sulfamethoxazole/sulfamathoxazole,
Tmp- trimethoprim/trimathopnme, Tmp/Smx - cotnmoxazole, Chlor -chloramphemcol/chloramph0mcol, Tel- TetracyclmeMtracycilne.
plates containing sulfamethoxazole and/or trimethoprim were
supplemented with lysed horse blood (5% ). The following
antibiotics were used at the concentrations indicated: amikacin
16 mg/L, amoxicillin/clavulanic acid 8/4 mg/L, ampicillin 8 mg/L,
aztreonam 8 mg/L, carbenicillin 16 mg/L, cefamandole 8 mg/L,
ciprofloxacin 1 mg/L, cephalothin 8 mg/L, chloramphenicol
8 mg/L, gentamicin 4 mg/L, kanamycin 16 mg/L, piperacillin
16 mg/L, sulfamethoxazole 256 mg/L, trimethoprim 8 mg/L,
trimethoprim/sulfamethoxazole 0.5/9 .5 mg/L, tetracycline
4 mg/L, tobramycin 4 mg/Land ticarcillin 16 mg/L. Susceptibility
testing was performed twice for each strain.
contenant du sulfamethoxazole et/ou du trimethoprime ant ete additionnees
de sang de cheval lyse (5%). Les antibiotiques suivants ant ete utilises aux
concentrations indiquees : amikacine 16 mg/L, amoxicilline/acide
clavulanique 8/4 mg/L, ampicilline 8 mg/L, aztreoname 8 mg/L,
carbenicilline 16 mg/L, cefamandole 8 mg/L, ciprofloxacine 1 mg/L,
cefalotine 8 mg/L, chloramphenical 8 mg/L, gentamicine 4 mg/L,
kanamycine 16 mg/L, piperacilline 16 mg/L, sulfamethoxazole 256 mg/L,
trimethoprime 8 mg/L, trimethoprime/sulfamethoxazole 0,5/9,5 mg/L,
tetracycline 4 mg/L, tobramycine 4 mg/Let ticarcilline 16 mg/L. Les
epreuves de sensibilite ont ete executees 2 fois pour chaque souche.
Les resultats sont presentes au Tableau 1. Les isolats de S. sonnei de 2
The results are shown in Table 1. The S. sonnei isolates from 2
Ontario outbreaks were susceptible to all 18 antimicrobials tested.
In contrast, isolates from the remaining outbreaks were resistant to
as few as 4 and as many as 9 different antibiotics. Each outbreak
was characterized by a unique resistance pattern that was consistent
for multiple isolates from the same outbreak. Resistances to
ampicillin, carbenicillin and ticarcillin were common to each of the
resistance patterns but resistances to amoxicillin/clavulanic acid,
cephalothin, chloramphenicol, cotrimoxazole, piperacillin,
sulfamethoxazole, tetracycline and trimethoprim varied from one
outbreak to another.
eclosions de !'Ontario etaient sensibles aux 18 antirnicrobiens utilises. En
revanche, les isolats provenant des autres eclosions etaient resistants a entre
4 et 9 antibiotiques chacun. Chaque eclosion se caracrerisait par un profil
de resistance unique qui etait uniforme pour de multiples isolats provenant
d 'une meme eclosion. La resistance al 'ampicilline, la carbenicilline et la
ticarcilline etait commune a tous les profils de resistance tandis que la
resistance a I' amoxilline/acide clavulanique, la cephalothine, le
chloramphenicol, le cotrimoxazole, la piperacilline, le sulfamethoxazole, la
tetracycline etla trimethoprime variaient d'une eclosion a l'autre.
During the last few years, several studies have provided
evidence for increasing antibiotic resistance among Shigel/a species
isolated in various regions of the world<2•3 •4>. In the United States,
recent oubreaks of shigellosis, some involving thousands of cases,
have been caused by multiply-resistants. sonnei strains<5•6•7>.
Antimicrobial resistance in this species is commonly associated
with the presence of R plasmitls<S>.
Au cours des quelques dernieres annees, plusieurs etudes ont laisse
entrevoir une resistance de plus en plus grande aux antibiotiques chez
I' espece Shigella isolee clans diverses regions du monde<Z.3.4>. Aux
Etats-Unis, des eclosions recentes de shigellose, dont certaines touchaient
des rnilliers de cas, ont ete causees par de souches de s. sonnei resistantes a
de nombreux antibiotiques <506•7>. Dans cette espece, laresistance aux
antibiotiques est associee a la presence de plasmides R<8>.
Our findings demonstrated the following: (i) resistance to more
than one antimicrobial agent (multiple resistance) is common
among S. sonnei strains associated with recent outbreaks in Canada;
(ii) resistance patterns may include resistance to one or more agents
used commonly for the treatment pf shigellosis; and (iii) resistance
patterns have a high degree of heterogeneity. 'I)lese results
emphasize the need for susceptibility testing of S. son~1ji isolates
associated with outbreaks using a broad set of {mtibiotips. Such
testing would serve as an aid to the epiderniologic investigation of
outbreaks and serve as a guide to the choice or·.agerit for those cases
requiring antimicrobial therapy. In addition, o'9f results indicate the
need for ongoing regional surveillance of resistance patterns among
Shigella from sporadic cases<9>. Finally, this study has provided
further support for the view that informed use of an~ibiotics in
shigellosis is essential to prevent the emergence of resistant strains.
Voici ce que nos resultats nous ant permis de conclure : i) la resistance a
plus d'un agent antimicrobien (resistance multiple) est courante parrni !es
souches de S. sonnei isolees au cours des eclosions recentes au Canada; (ii)
les profils de resistance peuvent montrer une resistance a Un OU plusieurs
agentS utilises couramment clans le traitement de la shigellose; et (iii) les
profils de resistance presentent une grande heterogeneite. Ces resultats font
ressortir la necessite de determiner la sensibilite a une vaste gamme
d'antibiotiques des isolats de S. sonnei associes a des epidernies. Ces
epreuves faciliteraient les enquetes epiderniologiques portant sur des
eclosions de cas en plus d'orienter le choix d'un agent pour les cas
justiciables d'un traitement antimicrobien. En outre, nos resultats font
ressortir la necessite d'une surveillance regionale continue des profils de
resistance des isolats de Shigella provenant de cas sporadiques(!l>. Enfin, la
presente etude a contribue a etayer l'idee qu'un usage avise d'antibiotiques
centre la shigellose est essentielle si I' on veut prevenir l' emergence de
souches antibioresistantes.
The authors thank Dr. C.M. Anand, Provincial Laboratory of
Public Health in Calgary, Alberta, M. Richter, Provincial
Laboratory of Public Health for Northern Alberta, Edmonton,
Alberta, and A. Boudreau, Saint John Regional Hospital, St. John,
New Brunswick, for providing strains used in this study. The
authors gratefully appreciate the assistance ofV. Brunins, Enteric
Reference Laboratory and the staff of the Susceptibility Testing
Les auteurs tiennei;t a remercier le D' C.M. Anand, Provincial
Laboratory of Public Health, a Calgary (Alberta), M. Richter, Provincial
Laboratory of Public Hea}th for Nortbem Alberta, a Edmonton (Alberta) et
A. Boudreau, Hopital regional de Saint-Jean, (Nouveau-Brunswick) qui leur
ant foumi les souches utilisees dans la presente etude. Les auteurs sont
reconnaissants de l' aide fournie par V. Brunins du Laboratoire de reference
des maladies enteriques ainsi que par le personnel Laboratoire de
determination de la sensibilite.
1. National Committee for Clj.uic.al Laboratory Standards.
Methods for dilution antimicrobial susceptibility tests for
bacteria that grow aerobically. 2nd ed. Approved Standard.
NCCLS DocumentM7-A2. Villanova, Pa: NCCLS,1990.
2. TauxeRV, PuhrND, Wells JG, Hargrett-BeanN, Blake P.
Antimicrobial resistance of Shigella isolates in the U.SA.: the
importance of international travellers. J Infect Dis
3. Ling J, Kam KM, Lam AW, French GL. Susceptibilities of
Hong Kong isolates of multiply-resistant Shigella spp. to 25
antimicrobial agents, including ampicillin plus sulbactam and
new 4-quinolones. Antimicrob Agents Chemother 1988;32:20-3.
4. Hamett N, McLeod S, AuYong Y, Krishnan C. Increasing
incidence of resistance among Shigellae to trimethoprim.
Lancet 1991;337:622.
1. National Committee for Clinical Laboratory Standards. Methods for .
dilution antiq!f{'gbialfguscevtjilig{J.~8/or bacteria that i:row
aerobically. 2"'n ed. _4!fov_ S ____. NCCLS Dogµment M7-A2.
Yillanoya. Pa : NCCLS. 1990.
2. Tauxe RV, Puhr ND, Wells JG, Hargrett-BeanN, Blake F.
Antimicrobial resistance ef Shigella isolates in the U.SA. .• tbe
iwortance if international {rayellers. J Infect Dis 1990; 162 :1107-11.
3. Ling J, Kam KM, Lam AW, French GL.
Agents hemother 1900;32 :20-3.
4. HarnettN, McLeod S, AuYong Y, Krishnan C. lncreasinf incidence qf
resistance among Shigellae to trimethoprjm. Lancet 199;337 :622.
5. Wharton M, Spiegel RA, Horan JM, et al. A larqe outbreak~
5. Wharton M, Spiegel RA, Horan JM, et coll. A large outbreak of
antibiotic-resistant shigellosis at a mass gathering. J fufect Dis
1990;162 :1324-8.
6. Lee LA, Ostroff SM, McGee HB, et coll. An outbreak Qfshi~ellosis at
an outdoor music festival. Am J Epidemiol 1991;133 :608-1 .
antibiotic-resistant shigellosis at a mass gathering. J fufect is
6. Lee LA, Ostroff SM, McGee HB, et al. An outbreak of
sh~e.llosi~ at an outdoor music festival. Am J Epidemiol
19 1,133.608-15.
7. Reeve G, Martin DL, Pappas J, ThomJ:son RE, Greene KD. An
o'utbreak of shirl/osis associated wit the consumption of raw
oysters. N Eng JMed 1989;321:224-7.
8. Bratoeva MP, John JF. Dissemination °!Jtrimethoprim-resistant
clones <fgShigel/a sonnei in Bulgaria. fufect Dis
1989;1 9:648-53.
9. CDC. Communi~ outbreaks of shigellosis - United States.
MMWR 1990;3 :509-13.
Source: MA Preston, PhD, Senior Bacteriologist, S Brown, BA,
Head, Susceptibility Testin~, A Borczyk, MSc, Chief,
Reference Bacteriology, Clinical Bacteriology Section,
Laboratory Services Branch, Ontario Ministry ofHealth,
Toronto, Ontario.
9. CDC. Comwunizy outbreaks efshigellosjs - United States. MMWR
1990;30 :509-13.
Source : MA Preston, PhD, Bacteriologiste principal, S Brown, BA, Chef,
epreuves de sensibilite, A Borczyk, MSc, Chef, Bacteriologie de
reference, Section bacteriologie clinique, Direction des services
de laboratoire, ministere de la Sante ile I' Ontario, Toronto
International Notes
Notes lnternatlonales
7. Reeve G, Martin DL, Pappas J, Thompson RE, Greene KD. d.a
outbreak ofshjgellosjs associated wj@the consumvtion of raw rzysters.
NEngl JMed 1989;321 :224-7.
8. Bratoeva MP, John JF. Dissemination QftrimethQl}rim-resistant clones
af'Shigella sonnei in Bulgaria. J Infect Dis 1989;159 :648-53.
On 14 March 1991, physicians at a hospital in Guatemala City
reported to the Institute of Nutrition of Central America and
Panama (INCAP) that a 2-year-old boy living in an orphanage in
Guatemala City had been hospitalized with dysentery; stool cultures
yielded Shigella dysenteriae type 1. Another child from the
orphanage had recently died from dysentery. During 18-21 March,
2 other young children from the orphanage were diagnosed with S.
dysenteriae type 1. On 21 March, health officials in Rabinal, in the
Department of Baja Verapaz, reported more than 100 cases of
dysentery to the Division of Epidemiology and Disease Control of
the Ministry of Health. This report summarizes the investigation of
these outbreaks.
Guatemala City
The orphanage houses approximately 1,50 children. No new
children had been admitted to the orphanage in 199.1, and no illness
had been reported among staff members. The inde~ patient was
treated with trimethoprim-sulfametlioxazole; however, a stool
culture yielded s. dysenteriae type 1 that' }vas resistant to
trimethoprim-sulfamethoxazole as well as to ampicillin,
chloramphenicol, and tetracycline. Stool'cultures from the 2
children who became ill after the index patient also yielded S.
dysenteriae type 1 with the same resistance pattern as the initial
isolate. Stool cultures from 39 children most likely to have had
contact with the index patient were negative, except for 1 isolate of
S.flexneri type 4. No additional cases of dysentery have been
reported from the orphanage.
Rablnal, Baja Verapaz
On 21 March, the Ministry of Health received a request from
health officials in the Department of Baja Verapaz (186 km north of
Guatemala City) for drugs to treat suspected amebiasis; the health
officials reported that more than 100 cases of dysentery had
occurred in residents of Rabinal, a community of approximately
10,000 persons. To determine the cause of the outbreak, INCAP
investigators travelled to Rabinal and collected stool specimens
from 16 persons with dysentery. Eleven samples yieldedS.
dysenteriae type l, resistant to chloramphenicol and tetracycline.
On the basis of these results, ill persons were treated with
On 2 and 10 April, investigators from INCAP and the Ministry
of Health again visited Rabinal. Surveys carried out by personnel of
the local health post showed that at least 540 persons had developed
dysentery since early March; 2 infants had died. Stool samples were
obtained from 46 patients with dysentery; 12 grew S. dysenteriae
type 1. For 10 patients, strains were indistinguishable from those
obtained in March. Strains from 2 patients were resistant to
ampicillin, chloramphenicol, tetracycline, and trimethoprimsulfamethoxazole. One of these resistant strains was from a boy
who had taken trimethoprim-sulfamethoxazole prophylaxis for
Le 14 mars 1991, les medecins d'un hopital de la ville de Guatemala
signalaient a l 'Institut de la Nutrition d' Amerique central et du Panama
(INCAP) I 'hospitalisation d'un enfant de 2 ans vivant dans un orphelinat de
Guatemala City et atteint de dysenterie; les cultures de selles ont permis
d'isoler Shigella dysenteriae type 1. Un autre enfant du meme orphelinat
etait mart recemment de dysenterie. Entre le 18 et le 21 mars, S. dysenteriae
type 1 a ete diagnostique chez 2 autres jeunes enfants du meme orphelinat.
Le 21 mars, les responsables de la sante de Rabinal, departement de Baja
Verapaz, signalaient plus de 100 cas de dysenterie a la Division de
l'epidemiologie et de la lutte contre lamaladie du Ministere de la Sante. Le
present rapport donne un resume des enquetes sur ces flambees
Guatemala City
L'orphelinat abrite environ 150 enfants. Aucun nouveau pensionnaire
n 'y est entre en 1991 et aucune maladie n' a ete signaloo parmi le personnel.
Le premier malade a ete traire a I' association trimethoprimesulfamethoxazole, mais une culture de selles a mis en evidence S.
dysenteriae type 1 resistant a cette association ainsi qu' a I' ampicilline, au
chloramphenicol et a la tetracycline. Les cultures de selles des 2 enfants
tombes malades ensuite ont aussi permis d'isoler S. dysenteriae type 1 qui
presentait le meme schema de resistance que le premier isolement. Les
cultures de selles des 39 enfants ·ayant tres vraisemblablement eu des
contacts avec le cas initial se sont reveloos negatives, a I' exception d'un
isolement de S.flexneri type 4. Aucun autre cas de dysenterie n'a ere
signale par I' orphelinat.
Rablnal, Ba)a Verapaz
Le 21 mars, les responsables de la sante du departement de Baja
Verapaz (a 186 km au nord de Guatemala City) ont demande au Minisrere
de la Sante des medicaments pour soigner des cas suspects d'amibiase; les
responsables de la sante ont signale plus de 100 cas de dysenterie parmi les
residents de Rabinal, communaute d'environ 10 000 habitants. Pour etablir
la cause de la flambee, les chercheurs de l'INCAP se sont rendus aRabinal
ou ils ont recueilli des echantillons de selles sur 16 personnes atteintes de
dysenterie. Onze echantillons contenaient s. dysenteriae type 1, resistant au
chloramphenicol et a la tetracycline. Sur la base de ces resultats, les malades
ont ete soignes a !'association trimethoprime-sulfamethoxazole.
Les 2 et 10 avril, les chercheurs de l'INCAP et du Minisrere de la Sanre
sont retoumes aRabinal. Les enquetes faites par le personnel des postes de
sanre locaux ont revele que 540 personnes au moins avaient contracre une
dysenterie depuis le debut du mois de mars; 2 nouveau-nes etaient morts.
Des echantillons de selles ont ete preleves sur 46 malades atteints de
dysenterie; dans 12 cas, les cultures ont permis d'isoler S. dysenteriae type
1. Pour 10 malades, les souches ne se differenciaient guere de celles qui
avaient ere obtenues au mois de mars. Les souches provenant de 2 malades
etaient resistantes a l' ampicilline, au chloramphenicol et ala tetracycline
ainsi qu'a !'association trimethoprime-sulfamethoxazole. L'une de ces
respiratory illness in mid-March. By the end of April, local
personnel reported that the number of new cases of dysentery was
souches resistantes avait ete isolee SUT un jeune gar\:Clil soigne a titre preventif a
l' association trimethoprime-sulfamethoxazole pour une affection respiratoire
vers le milieu du mois de mars. Ala fin du mois d'avril, le personnel local a
signale que le nombre des cas nouveaux de dysenterie etait en baisse.
Editorial Note: Pandemic S. dysenteriae type 1 (the Shiga
bacillus) affected Central America from 1969 to 1972. In
Guatemala, there were more than 112,000 cases and at least 10,000
Note de la redaction : S. dysenteriae type 1 (bacille de Shiga) al'etat
pandemique a affecte l 'Amerique centrale de 1969 a 1972. On a compte plus de·
112 000 cas et au moins 10 000 deces au Guatemala.
Since 1972, no major outbreaks of dysentery caused by the
Shiga bacillus have occurred in Central America. However, in
1988, the number of these infections reported in the United States
increased 5-fold over the annual mean from the preceding decade,
and most ill persons had recently visited the Yucatan peninsula in
Mexico. The antimicrobial resistance pattern and plasmid profile
were similar to those of the 1969-1972 pandemic strain. In 1989,
the number of imported cases decreased in the U.S., and outbreaks
of documented Shiga infection have not been reported from
Depuis 1972, aucune flamooe majeure de dysenterie due au bacille de Shiga
ne s 'est produite en Amerique centr!lle. Cependant, en 1988, le nombre des
infections de ce type signalees aux Etats-Unis etait 5 fois plus eleve que la
moyenne annuelle de la decennie precedente, et la majorite des malades s 'etaient
rendus recemment clans la peninsule du Yucatan, au Mexique. Le schema de
resistance antimicrobienne et le profil plasmidique etaient les memes gue pour la
souche pandemique de 1969 a 1972. Le nombre de cas importes aux Etats-Unis a
regresse en 1989 et aucune flambee d'infection confirmee comme etant due au
bacille de Shiga n' a ete signalee par le Mexique.
Appropriate antimicrobial therapy decreases the severity and
duration of dysentery caused by Shigella. Nalidixic acid is effective
therapy for strains resistant to other antimicrobials; the newer
quinolones are also effective, but are costly and have not been
approved for use in children. Moreover, Shigella can rapidly
acquire resistance, and is likely to do so in settings in which
antimicrobials are commonly used and shigellosis is endemic. The
recent cases in Guatemala underscore the need for continued
surveillance for enteric pathogens, especially those associated with
dysentery. Once Shigella is identified, determination of the
antimicrobial resistance pattern and the modes of transmission are
important in designing control measures. As during the 1969-1972
pandemic, the recent cases in Rabinal were initially misdiagnosed
as amebiasis, a misdiagnosis that may be common in some
locations. Prompt culturing facilitated the correct diagnosis and
appropriate therapy.
Un traitement antimicrobien approprie permet de reduire la gravite et la duree
de la dysenterie due aShigella. L'acide nalidixique est efficace contre les
souches resistantes aux autres antimicrobiens; les quinolones, plus recents, sont
aussi efficaces, mais ils coutent cher et leur utilisation chez l'enfant n'a pas ere
approuvee. En outre, Shigella peut devenir rapidement resistant, particulierement
lorsque des antimicrobiens sont couramment utilises et dans les regions OU la
shigellose est endemique. Les cas recents survenus au Guatemala soulignent la
necessite de poursuivre la surveillance des agents pathogenes intestinaux, surtout
ceux qui sont associes a la dysenterie. Une fois Shigella identifie, il importe de
definir le schema de resistance aux antimicrobiens et les'modes de transmission
pour concevoir les mesures de lutte. Comme lors de la pandemie de 1969 a 1972,
les cas qui se sont declares recemment aRabinal ont d abord ete diagnostiques a
tort comme des cas d' amibiase, erreur qui peut etre frequente dans certains
endroits. La rapidite des cultures a pennis de poser un diagnostic correct et
d' administrer le traitement approprie.
The appearance of the Shiga bacillus in 2 locations separated by
more than 100 km suggests this pathogen may be present in other
areas of Guatemala. The detection of trimethoJJI.imsulfamethoxazole-resistant strains early in the outbreak Yighlights
the need for continued monitoring of resi_stance,
L'apparition du bacille de Shiga en 2 points distants de plus de 100 km donne
a penser que cet agent pathogene pourrait etre present dans d'autres regions du
Guatemala. L 'isolement de souches resistantes al' association trimethoprimesulfamethoxazole au debut de la flambee souligne la necessite de continuer a (_surveiller la resistance.
Source: Morbidity and Mortality Weekly Report, Vol 40, No 25,
far lllll'VOillancc pwposcs and is available free of charge upon request. Many of tho articles
contain prolimhwy information and f'urthcr confinruition may bo obtained from tho sources
quolod. Tho Department of Health and Welfare docs not assume rcsponaibilily for accurscy or
authenticity. ContributiODD arc welcomed (in the officW langung<> of your choice) from anyone
working in tho ho alth f1Cld nnd will not preclude publication clocwborc.
SclontificAdvisary Board:
Dr. K.Rozec
Eleanor Paulaon
Nicole Beaudoin
Joarmc Regnier
Gertrude Tardiff
Bureau of Communicnblc Disease Epidemiology
Laboratory Centi<: for Disease Con!rol
Tunney'• Putum
<YITAWA, Ontnrlo
Source: Morbjdit:y and Mortality Weekly ReJ20rt. Vol 40, n° 25, 1991.
Tho Canada Dl!cuea Weekly Rcportprcscllls curront information on infectious and other di!case1
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