Open AccessAntimicrobial Susceptibility and Mechanisms of Resistance in Shigella and Salmonella Isolates from Children under Five Years of Age with Diarrhea in Rural Mozambique
Author(s) -
Inácio Mandomando,
Dinis Jaintilal,
María J. Pons,
Xavier Vallés,
Mateu Espasa,
Laura Mensa,
Betuel Sigaúque,
Sergi Sanz,
Jahit Sacarlal,
Eusébio Macete,
Fátima Abacassamo,
Pedro L. Alonso,
Joaquı́m Ruiz
Publication year - 2009
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.01282-08
Subject(s) - shigella , microbiology and biotechnology , salmonella , shigella flexneri , biology , ciprofloxacin , shigella sonnei , antibiotic resistance , nalidixic acid , trimethoprim , multiple drug resistance , sulfamethoxazole , shigella boydii , virology , drug resistance , antibiotics , bacteria , gene , escherichia coli , genetics
The antimicrobial susceptibility and mechanisms of resistance of 109Shigella and 40Salmonella isolates from children with diarrhea in southern Mozambique were assessed. The susceptibility to seven antimicrobial agents was tested by disk diffusion, and mechanisms of resistance were searched by PCR or colorimetric method. A high proportion ofShigella isolates were resistant to chloramphenicol (Chl) (52%), ampicillin (Amp) (56%), tetracycline (Tet) (66%), and trimethoprim-sulfamethoxazole (Sxt) (84%). Sixty-five percent of the isolates were multidrug resistant.Shigella flexneri isolates were more resistant than those ofShigella sonnei to Amp (66% versus 0.0%,P < 0.001) and Chl (61% versus 0.0%,P < 0.001), whereasS. sonnei isolates presented higher resistance to Tet thanS. flexneri isolates (93% versus 64%,P = 0.02). Resistance amongSalmonella isolates was as follows: Tet and Chl, 15% each; Sxt, 18%; and Amp, 25%. Only 3% ofSalmonella isolates were resistant to nalidixic acid (Nal), and none to ciprofloxacin or ceftriaxone (Cro). AmongSalmonella isolates, multiresistance was found in 23%. AmongShigella isolates, antibiotic resistance was related mainly to the presence ofoxa-1 -like β-lactamases for Amp,dfrA1 genes for Sxt,tetB genes for Tet, and Chl acetyltransferase (CAT) activity for Chl. AmongSalmonella isolates, resistance was conferred bytem- like β-lactamases for Amp,floR genes and CAT activity for Chl,tetA genes for Tet, anddfrA1 genes for Sxt. Our data show thatShigella isolates are resistant mostly to the most available, inexpensive antibiotics by various molecular mechanisms but remain susceptible to ciprofloxacin, Cro, and Nal, which is the first line for empirical treatment of shigellosis in the country.