Frequency of Enterobacter sakazakii in Clinical Specimens and its Antimicrobial Resistance

Abstract

This study was carried out in Khartoum State during the period from November 2008 to March 2009, to determine the frequency of Enterobacter sakazakii in clinical specimens and then to determine its resistance to traditionally used antimicrobial agents. Three hundred and eleven urine specimens, eleven wound specimens, and sixty seven stool specimens were collected from patients attended Khartoum Teaching Hospital, Gaffer Iben Auff Specialized Hospital for Children, and Omdurman Teaching Hospital. The urine specimens and wound swabs were cultured on blood and MacConkey's agars for primary isolation of pathogen, while stool specimens were cultured on selenite F Broth and incubated over night then subcultured on xylose lysine deoxycholate agar. Identification of , the E. sakazakii was done by colonial morphology, Gram s stain and biochemical tests using API 20 E. Modified Kirby-Baur disc diffusion method was adopted to determine the resistance rate of E. sakazakii to chloramphenicol, ciprofloxacin, tetracycline, gentamicin, ceftazidime, amikacin, ceftriaxone, tecarcyline, trimoxazole, amoxicillin, amoxyclav, nalidixic acid, nitrofuratoin, co- cephotaxime, and tobramycin. Minimum inhibitory concentration (MIC) of above mentioned antimicrobial agents were determined by E. test. Out of the three hundred and eleven urine specimens, eleven wound swab, and sixty seven stool specimens examined, only 6 (1.5%) E. sakazakii were recovered, 4 (1.2%) from urine, 1(9.1%) from wound, 1 (1.5%) from stool. The results revealed that the antimicrobial resistance of E. sakazakii was as follow; ceftazidime, amoxicillin, amoxyclav (100% each), co-trimoxazole, tecarcyline (83.3% each), chloramphenicol, tetracycline, ceftriaxone, nitrofuratoin, cephotaxime, tobramycin (66.7% each), ciprofloxacin, amikacin and nalidixic acid (16.7% each). No isolate was found to be resistant to gentamicin. The result indicated that the MIC, MIC 50 and MIC90 of nitrofurantoin (3- >240μg/ml, 60μg/ml and >240μg/ml ), nalidixic acid (0.5->240μg/ml, 4μg/ml and 4μg/ml ), co-trimoxazole (0.1->240μg/ml, >240μg/ml and >240μg/ml ), chloramphenicol (0.01->240μg/ml, 4μg/ml and 4μg/ml ), amikacin (0.1- 64μg/ml, 0.1μg/ml and 0.5μg/ml ), gentamicin ( 0.1-30, 5μg/ml and 30μg/ml), tobramicin ( 1-16μg/ml, 4μg/ml and 8μg/ml ), ciprofloxacin (0.001-0.5μg/ml, 0.25μg/ml and 0. 5μg/ml ), ceftriaxone (0.1-60μg/ml, 30μg/ml and 30μg/ml ), ceftazidime ( 0.1->240μg/ml, 15μg/ml and 15μg/ml ), tetracycline (0.01- 3μg/ml, 2μg/ml and 3μg/ml ), tecarcycline (10->240μg/ml, >240μg/ml and >240μg/ml ), cephotaxime amoxycillin (0.1->240μg/ml, (0.1->240μg/ml, 60μg/ml and >240μg/ml and >240μg/ml ), 60μg/ml ), amoxyclav ( 2- >240μg/ml, >240μg/ml and >240μg/ml). The study concluded that the presence of E. sakazakii in clinical specimens was slightly high. The antimicrobial resistance for E. sakazakii was high too.