Mechanism of resistance to antimicrobial agents in Shigella strains isolated from stools among children under 5 years of age in southern Mozambique

Abstract number: R2313

Mandomando I., Jaintilal D., Mensa L., Pons M., Ruiz J., Alonso P.

Objective: To characterise the molecular mechanisms of antimicrobial resistance of Shigella spp. strains isolated from stools among children under 5 years of age in Southern Mozambique

Methods:Antimicrobial susceptibility testing: Shigella strains isolated from children <5 years of age complaint with diarrhoea in Manhiça District Hospital (MDH), Southern Mozambique were tested for antimicrobial susceptibility to ampicillin (Amp), chloramphenicol (Chl), cotrimoxazole (SXT), tetracycline (Tet), nalidixic acid (Nal), Ceftriaxone (Cro) by disk diffusion method.

Detection of the mechanism of resistance: The presence of the cmlA and floR genes associated to Chl resistance; tetA, tetB, and tetG genes associated to Tet resistance; genes encoding b-lactamases (OXA-1, OXA-2, TEM-like, SHV-like) associated to Amp resistance, and dihydrofolate reductase genes were carried out by PCR and electrophoresis in 2% agarose gel.

Results: The molecular mechanisms of antimicrobial agents resistance in Shigella strains [Ampicillin (Amp), Tetracycline (Tet), Chloramphenicol (Chl) and Trimetoprim-Sulfametoxazole (SXT)] were analysed. At total 111 isolates were analysed. The most frequently detected encoding b-lactamases genes were oxa-like, from which oxa-1 (55 isolates) was the most frequent followed by carb (7 isolates), while tem (4 isolates) and oxa-2 (3 isolates) were recovered in low prevalence.

Resistance to Tet were mainly related to tetB (47 isolates), tetG (18 isolates), and tetA (9 isolates), genes. Nor floR neither cmlA genes were found to be related to Chl resistance; however CAT is not researched yet. Several genes encoding dihydrofolate-reductases (dfrA1, dfrA5, dfr14, dfr7) were responsible for SXT resistance strains, being dfrA1-like (52 isolates), the most frequent followed drf14 (24 isolates) and dfr7 (3 isolates only).

Conclusions: Despite the fact that the isolates were recovered in a specific geographic area, an high heterogeneity in the molecular mechanisms of antimicrobial resistance has been detected.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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