Methicillin-resistant Staphylococcus aureus isolated from various types of hospital infections in pediatrics: Panton-valentine leukocidin, staphylococcal chromosomal cassette mec SCCmec phenotypes and antibiotic resistance properties

Background: Staphylococcus aureus has long been considered as a major pathogen of hospital infections. Objectives: The present investigation was carried out to study the distribution of Staphylococcal Chromosomal Cassette mec (SCCmec) types, Panton-Valentine Leukocidin (PVL) gene and antibiotic resistance properties of Methicillin Resistant Staphylococcus aureus (MRSA) strains isolated from various types of infections found in Iranian pediatric patients. Patients and Methods: Two-hundred and fifty-five clinical specimens were collected from four major provinces of Iran. Samples were cultured and the MRSA strains were subjected to Polymerase Chain Reaction (PCR). The patterns of antibiotic resistance were determined using the disk diffusion method. Results: Seventy-four out of 255 (29.01) clinical samples were positive for MRSA. Of the 74 MRSA strains, 47 (63.51) were PVL positive. The clinical samples of respiratory tract infections (36.36), those from the Shiraz province (37.87) and samples collected during the summer season (56.48) were the most commonly infected samples. The most commonly detected antibiotic resistance genes were tetK (89.18), mecA (71.62), msrA (56.75) and tetM (54.05). Methicillin Resistant Staphylococcus aureus had the highest levels of resistance against penicillin (100), tetracycline (98.64), ampicillin (93.24) and oxacillin (93.24). The most commonly detected SCCmec types in the MRSA strains were type V (18.91) and III (17.56). Conclusions: Regular surveillance of hospital-associated infections and monitoring of the antibiotic sensitivity patterns are required to reduce the prevalence of MRSA. We recommend initial management of children affected by MRSA with imipenem, lincomycin and cephalothin prescriptions. © 2015, Ahvaz Jundishapur University of Medical Sciences

Shiga toxigenic Escherichia coli in Iranian pediatric patients with and without diarrhea: O-serogroups, virulence factors and antimicrobial resistance properties

Background: Shiga-toxigenic Escherichia coli is an important human pathogen cause of diarrhea, hemorrhagic colitis, hemolytic uremic syndrome and thrombotic thrombocytopenic purpura in humans is a significant public health. Objectives: The aim of this study was to determine the molecular characteristics and antimicrobial resistance properties of Shiga toxigenic Escherichia coli (STEC) strains with respect to their seasonal, age and geographical distributions in Iranian pediatric patients with and without diarrhea. Patients and Methods: Four hundred and eighty swab samples were taken from pediatric patients with and without diarrhea of four major provinces of Iran. Swab samples were immediately cultured and the positive culture samples were analyzed by the polymerase chain reaction (PCR) method. Finally, antimicrobial susceptibility testing was performed using the disk diffusion method in Mueller-Hinton agar. Results: In total, 118 out of 200 diarrheic stool samples (59) and 77 out of 280 non-diarrheic stool samples (27.5) were positive for E. coli. Samples taken from one to ten months old cases (73.33) and those from Shiraz province (81.13) were the most commonly infected. Samples taken in the summer season (91.66) were the most commonly infected. A significant difference was shown between AEEC and EHEC strains of E. coli. The genes encoding Shiga toxins and intimin protein were the most commonly detected in all strains. O26 (33.33), O111 (18.18) and O91 (12.12) serogroups had the highest incidence in patients with and without diarrhea. Prevalence of the genes that encode resistance against ampicillin (CITM), gentamicin (aac(3)-IV) and tetracycline (tetA) were 80.30, 75.75 and 65.15, respectively. The STEC strains harbored the highest levels of resistance against ampicillin (84.84), gentamycin (78.78), tetracycline (50) and sulfamethoxazole (40.90) antibiotics. We found that 55.08 of diarrheic and 1.29 of non-diarrheic E. coli isolates were resistant to more than six antibiotics. Conclusions: Accurate control programs should be organized for antibiotic prescription especially during warmer seasons in Iran. Primary treatment of diarrheic patients with co-trimoxazole, cefotaxime and ceftriaxone is effective. © 2015, Iranian Red Crescent Medical Journal