الفهرس 
ShigellosisOnly 14 pages are availabe for public view
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Abstract
Shigellosis (bacillary dysentery) continues to be a major public health
burden, particularly in developing countries. During the period from March 2019
to December 2020 , 62 Shigella isolates out of 920 fresh fecal specimens of
diarrheic children admitted to Pediatric Department at Tanta University
Hospitals (The Diarrhea and Nutrition Unit) , Banha Children Specialist Hospital
, EL-Mahalla Fever Hospital and Mansoura Fever Hospital were recovered . The
incidence of shigellosis associated diarrhea was 6.7% . Identification of the tested
isolates was confirmed using microscopical, cultural, standard biochemical tests
as well as serological tests . S.flexneri was the most frequently isolated (61.3%)
serogroup, while 32.3% and 6.5% were S.sonnei and S.boydii , respectively . S.
dysenteriae spp. was not detected in our study.
It was found that Shigella associated diarrhea was more prevalent in
children aged between 2 and 2.5 years. Common manifestations included watery
diarrhea (85.5 %) , fever (45.2 %) , and abdominal pain (25.8 %) . bloody
diarrhea , however, occurred in only 12.9% of cases . PCR technique was used
for the detection of genes specific for the genus (ipaH1) , species (wzy , wbgZ ,
ipaH for S.boydii, S.sonnei and S.flexneri respectively) , major virulence genes
namely ipaH , virA , icsA , sigA , sat , sepA , pic , set1A , set1B , sen/ospD3 ,
stx1 , stx2 and genes encoding resistance to commonly used antibiotics in clinical
practice (blaCTX-M & blaTEM , qepA & qnrs , aadA1 ,sul1 genes).
abstract
The set1A/set1B that encode Shigella enterotoxin 1 (ShET-1) were found in
50% of only S.flexneri isolates and absent in other Shigella species .On the other
hand , stx1/stx2 encoding ShET-1 and pic encoding protein involved in
colonization were not detected in any of the studied isolates . Regarding
antibiotic resistance genes it was found that the tested isolates harboured all
except blaCTXM antibiotic resistance gene.
All the studied 62 Shigella isolates were tested for susceptibility to each
of 17 different antimicrobial agents. High frequency of resistance was observed
to Amoxicillin + Clavulanic acid (91.9%) , Cefotaxime (77.4%) , Ceftazidime
(69.4%) , and Trimethoprim/Sulfamethoxazole (69.3 %) , while relatively low
rate of resistance was found to colistin (17.7%) , tetracyclines (9.7%) and
Norfloxacin (9.7 %) . Imipenem demonstrated the highest activity where all
tested isolates were sensitive to this drug.
Resistance to antimicrobial drugs in Shigella spp. can result from several
mechanisms, such as extrusion of drugs by active efflux pumps, decrease in
cellular permeability, and overexpression of drug-modifying and -inactivating
enzymes or target modification by mutation. Phenotypically was found that 49
out of 62 (79 %) Shigella isolates produced β-Lactamase enzymes . Molecular
studies revealed that genes encoding antibiotic resistance like blaTEM for
penicillins resistance , qepA & qnrs for quniolones and flouroquinolones ,
aadA1 gene for aminoglycosides & sul 1 gene for Cotrimoxazole
(Trimethoprim / Sulfamethoxazole) were harboured by Shigella species isolates
.On the other hand, the penicillin resistance gene , blaCTX-M was not detected
among tested isolates