Abstract
Background:
The emergence of multidrug resistance (MDR) is a serious problem in treating shigellosis. There are limited existing data examining the change in the antimicrobial resistance profile of
Shigella
in Egypt. We previously reported that 58% of the
Shigella
isolates in Egypt were resistant to at least one member of the three different antimicrobial groups. This study was performed to determine the antimicrobial resistance profile of
Shigella
, determine their possible mechanisms of resistance, and compare their resistance profile to those reported 20 years ago.
Patients and Methods:
Stool samples were collected from 500 subjects and processed for the isolation and identification of
Shigella
. The susceptibility of the isolates to 11 different antimicrobials was determined using the disc diffusion method.
Results:
Of 500 stool cultures, 24 (4.8%) samples were positive for
Shigella
. There was a high percentage of resistance to ampicillin (88%), tetracycline (83%), and sulfamethoxazole–trimethoprim (75%). Also, there was a moderate percentage of resistance to chloramphenicol (46%), streptomycin (42%), ceftazidime (33%), and cefotaxime (25%). A lower percentage of resistance was recorded for amikacin, nalidixic acid (17% each), and ofloxacin (7%), while no resistance was found to ciprofloxacin (0%). Twenty-one of the isolates (88%) were resistant to at least three different antimicrobial groups (indicating MDR). The average number of antimicrobial agents to which the
Shigella
isolates were resistant was 4.3±1.4, while it was 3.4±1.5 in the same locality in 1994.
Conclusion:
These data demonstrate that there is a marked increase in MDR and change in the resistance patterns of
Shigella
over the past 20 years.