Alexandra Lapusan

First study of Salmonella in meat in Romania.

INTRODUCTION The increasing antimicrobial resistance of Salmonella isolates is of major public health concern, but information regarding these aspects is still lacking in Romania. This study focused on a detailed and accurate investigation concerning prevalence, serotypes, and antimicrobial resistance patterns of Salmonella strains, isolated from pork and chicken meat, collected from all regions of Romania in 2011. METHODOLOGY The research was conducted on 650 samples of chicken and pork meat collected from production units and retail markets located in various regions of Romania. A total of 149 Salmonella isolates were recovered (22.92%), serotyped, confirmed by PCR, and further tested for antimicrobial susceptibility. RESULTS Thirteen Salmonella serovars were identified; predominant serovars included Infantis, Typhimurium, Derby and Colindale. Multiple resistance was found in 83.22% (n = 124) of the isolates. The isolates were frequently resistant to tetracycline (80.53%), streptomycin (81.21%), sulfamethoxazole (87.25%), nalidixic acid (65.10%), and ciprofloxacin (42.95%). Additionally, a markedly lower resistance rate was observed for ampicillin (20.81%), chloramphenicol (16.78%), and ceftazidime (11.41%). Among 137 resistant Salmonella isolates, 35 different resistance patterns were found. CONCLUSION A high prevalence of Salmonella spp. and a relatively high resistance rate to multiple antimicrobials was found. This data indicates that chicken and pork meat could constitute a source of human exposure to multidrug-resistant Salmonella and therefore could be considered a potential vehicle of resistant Salmonella foodborne diseases. Further actions are needed to succesfully implement a national surveillance program for better monitoring of these resistant pathogens.

Strain dependent UV degradation of Escherichia coli DNA monitored by Fourier transform infrared spectroscopy

In this work we present a method for detection of DNA isolated from nonpathogenic Escherichia coli strains, respectively. Untreated and UV irradiated bacterial DNAs were analyzed by FT-IR spectroscopy, to investigate their screening characteristic features and their structural radiotolerance at 253.7nm. FT-IR spectra, providing a high molecular structural information, have been analyzed in the wavenumber range 800-1800cm(-1). FT-IR signatures, spectroscopic band assignments and structural interpretations of these DNAs are reported. Also, UV damage at the DNA molecular level is of interest. Strain dependent UV degradation of DNA from E. coli has been observed. Particularly, alterations in nucleic acid bases, base pairing and base stacking have been found. Also changes in the DNA conformation and deoxyribose were detected. Based on this work, specific E. coli DNA-ligand interactions, drug development and vaccine design for a better understanding of the infection mechanism caused by an interference between pathogenic and nonpathogenic bacteria and for a better control of disease, respectively, might be further investigated using Fourier transform infrared spectroscopy. Besides, understanding the pathways for UV damaged DNA response, like nucleic acids repair mechanisms is appreciated.