Public health aspects of Shiga toxin-producing Escherichia coli (STEC) strains in sheep and goats of Bakhtiari pastoral tribe, Iran.

Nomadic populations do not have permanent settlements as they move their livestock between grazing areas in different seasons; such movements may have great impact on dissemination of food-borne pathogens in various regions. The aim of this study was to characterize Shiga toxin-producing Escherichia coli (STEC) strains as a food-borne pathogen in sheep and goats of Bakhtiari pastoral tribe in Iran. In the present study, 72 fecal samples were obtained from 26 sheep and 46 goats. First, all recovered E. coli isolates were screened for stx gene. After detection of stx-positive isolates, the virulence genes including stx1, stx2, eae, ehly, saa, astA, subAB, terD, and the genetic markers of O Island 57 (Z2098 and Z2099) were investigated. Also fifteen important STEC O-serogroups were determined using PCR assays. Results showed that 27 animals (27/72; 37.5%) carried STEC strains including 16/26 (61.6%) sheep and 11/46 (23.9%) goats. All STECs were eae-negative but 81.4% (22/27) were positive for saa. The most prevalent virulence profile was stx1/stx2/ehly/saa/subAB (37%; 10/27). Most STECs (24/27) were positive for at least one of the selected OI-57 markers. The O91 (n = 6), O5 (n = 3), O113 (n = 1), O128 (n = 1), and O104 (n = 1) were the detected O-serogroups in this study. It is concluded that such moving animal populations could have public health concerns which have to be addressed in the future.

Molecular survey of mcr1 and mcr2 plasmid mediated colistin resistance genes in Escherichia coli isolates of animal origin in Iran.

OBJECTIVES: The emergence of colistin-resistant Enterobacteriaceae from human and animal sources is one of the major public health concerns as colistin is the last-resort antibiotic for treating infections caused by multidrug-resistant Gram-negative bacteria. We aimed to determine the prevalence of the prototype widespread colistin resistance genes (mcr-1 and mcr-2) among commensal and pathogenic Escherichia coli strains isolated from food-producing and companion animals in Iran. RESULTS: A total of 607 E. coli isolates which were previously collected from different animal sources between 2008 and 2016 used to uncover the possible presence of plasmid-mediated colistin resistance genes (mcr-1 and mcr-2) by PCR. Overall, our results could not confirm the presence of any mcr-1 or mcr-2 positive E. coli among the studied isolates. It is concluded that despite the important role of food-producing animals in transferring the antibiotic resistance, they were not the main source for carriage of mcr-1 and mcr-2 in Iran until 2016. This study suggests that the other mcr variants (mcr-3 to mcr-9) might be responsible for conferring colistin resistance in animal isolates in Iran. The possible linkage between pig farming industry and high level of mcr carriage in some countries needs to be clarified in future prospective studies.

Comparative effects of granulocyte-colony stimulating factor and colistin-alone or in combination on burn wound healing in Acinetobacter baumannii infected mice.

BACKGROUND AND OBJECTIVES: Burn wounds are one of the most important health problems all over the world because infection after burn can delay wound healing. Treating burn wounds with granulocyte-colony stimulating factor (G-CSF) is known to improve healing of injured tissue. In addition, colistin is prescribed as an effective treatment. The aim of this study was to evaluate the effect of G-CSF and colistin alone or in combination with G-CSF on wound healing of Acinetobacter baumannii (A. baumannii) infected burns. MATERIALS AND METHODS: This study was performed between January 2016 and April 2018. Burn wounds were experimentally induced in 36 mice. The wounds were inoculated with A. baumannii. In a 7-day period, burn wounds in each group were daily treated with subcutaneous injections (0.1 ml) of saline, G-CSF, colistin, and G-CSF plus colistin. After killing the animals, the size of the wound, number of leukocytes in the skin and microbial growth were evaluated. A value of p ≤ 0.05 was considered statistically significant. RESULTS: Wound healing in the G-CSF plus colistin group was significantly higher than the control group and the G-CSF group (P = 0.023 and P = 0.033, respectively). In G-CSF+colistin group, the number of leukocytes was higher than the control group considerably (P = 0.007). On the 7th day of treatment, number of positive bacterial cultures in the colistin and the G-CSF plus colistin groups was lower than other groups with a significant difference. CONCLUSION: Concurrent consumption of G-CSF and antibiotics can control burn infection and enhance the immune system towards wound healing.