Antibiotic Resistance of Sorbitol Non-Fermenting Shiga Toxin Producing Escherichia coli Isolated from Buffaloes

Sorbitol non-fermenting Shiga toxin producing Escherichia coli (SNF-STEC) is considered as a significant emerging pathogen. Though, cattle and buffaloes are the chief reservoir, species like goat, sheep, deer and other ruminants can also harbor this pathogen. Therefore, this pathogen can easily be transmitted to human and other animals through food chain and their environment. The present study, aimed to ascertain the antibiotic resistance profile of SNF-STEC isolates from buffaloes as well as to detect the resistance genes. A total of 33 sorbitol non-fermenting (SNF) E. coli isolates were tested against ten commonly used antibiotics both in human and veterinary medicine. Results revealed that 78.8% isolates were resistant to sulfamethoxazole-trimethoprim and nalidixic acid whereas 60.6% to tetracycline and 48.5% to doxycycline. The majority of the isolates were found sensitive to both gentamycin and ciprofloxacin (90%) followed by erythromycin (66.7%) and ceftriaxone (51.5%). Of 33 SNF E. coli, 12 were STEC harboring both stx1 and stx2 gene that dictated 66.7% isolates were found resistant to sulfamethoxazole-trimethoprim and nalidixic acid followed by ampicillin (58.3%) and tetracycline (58.3%). blaTEM was detected in 66.7% ampicillin resistant isolates and sul2 was exposed in 34.6% sulfamethoxazole-trimethoprim resistant isolates. sul1 gene was negative for the sulfamethoxazole-trimethoprim resistant isolates.

Serotipos y aislamientos de Escherichia coli productora del subtipo Stx2 de la toxina Shiga provenientes de canales y heces de ganado bovino

Shiga toxin E. coli (STEC) is an important pathogen responsible for foodborne illness, this have been related with epidemic outbreaks in the past, mainly because of consumption of bovine meat. The objective of this study was identify the serotypes and Stx2 subtypes and associate them with their possible epidemiology. There were analyzed a total of 65 isolates from the collection of the Centro de Investigación y Estudios Avanzados en Salud Animal, Facultad de Medicina Veterinaria y Zootecnia of the Universidad Autónoma del Estado de México, from carcasses and feces of bovines at three different Municipal slaughterhouses. The identification of Stx2 gene by PCR at final point, sequencing and analyzed with the help of BLAST software. There were found O157:H7, O70:H16, O91:H10, O112ac:H2, O128ac:H26 serotypes, which have been reported to be present at infectious outbreaks previously by foodborne worldwide; 63.07% (41/65) of the Escherichia coli strains got amplified for Stx2 and after BLAS analysis it was confirmed its presence and a hypothetic protein. The presence of this serotypes in combination with different subtype’s, Stx2a, Stx2c, Stx2d, in carcasses and feces of bovine in must be considered as a potential risk for diseases an important problem of the public health.

Biological and molecular characterization of six Shiga toxin-producing Escherichia coli (STEC) strains encoding the stx2 gene in Colombia

ABSTRACTShiga toxin-producing Escherichia coli (STEC) is a bacterial pathogen that cause diarrhea and severe human diseases. Its principal virulence factor are the Shiga toxins Stx1 and Stx2 which have been identified diverse subtypes considered to be responsible for severe complications of STEC infection. These toxins are encoded in temperate bacteriophages and their expression is linked to phage lithic cycle, which is regulated by late genes and the Q anti-terminator protein. The aim of this study was to characterize biologically and molecularly STEC strains encoding stx2 gene isolated from cattle feces in Colombia. We selected six STEC strains, which were evaluated its Stx production, the Stx2 subtypes, induction of the lithic cycle of bacteriophages and its late region. The results evidenced two highlighted strains with high levels of Stx production and induction of the lithic cycle, compared with the others. Likewise, the strains evaluated showed three Stx2 subtypes: Stx2a, Stx2c, and Stx2d. Regarding the late region, most of the strains carried the qO111 allele and only one strain showed differences in the ninG gene. Although the sample was limited, variability was observed in the Stx production assay, induction of the lithic cycle, Stx2 subtypes and late region of the phages, which could indicate the diversity of the phages carrying STEC strains in Colombia.

PREVALENCE AND CHARACTERIZATION OF SHIGATOXIGENIC ESCHERICHIA COLI IN BROILER BIRDS IN MYMENSINGH

Shigatoxigenic Escherichia coli (STEC) are major food-borne pathogens. They transmit to human through contaminated meat and meat products of animals and poultry, and frequently associated with various types of human illness including haemolytic uremic syndrome. This preliminary study showed the prevalence of STEC in 60 cloacal swab samples of live healthy broiler chickens collected randomly when sold at a wholesale market in Mymensingh district of Bangladesh. Isolation and identification of E. coli was carried out using Eosin Methylene Blue (EMB) agar media and 16S rRNA gene specific polymerase chain reaction (PCR). Among the 60 samples, 49 (81.67%) were found positive to E. coli. These E. coli isolates were screened for the detection of STEC by PCR using stx1 and stx2 gene specific primers. Among the 49 positive samples, 5 (10.20%) were found positive for stx1 gene, and 26 (53.06%) were positive for stx2 gene. In addition, 6 (12.24%) isolates were found positive to both stx1 and stx2 genes, and the remaining 12 (22.46%) were negative. The high prevalence ofSTEC in the broiler chicken alarms the public health impact as the people are always in close contact with these live broiler chickens in the open market as well as processing of meat at home before cooking. However, further studies are required to uncover the major source(s) for the transmission of STEC to human in ruralBangladesh.

Detection of shiga toxin producing Escherichia coli isolated from children and cattle using PCR technique

This study was undertaken to detect STEC isolates, gene(Stx2) in Escherichia coli isolatesand characterize them by biochemical tests , enterohemolysin production and PCR.During aperiod of seven months (November 2007 to May 2008), a total of 280 fecal samples werecollected from 120 hospitalized children suffering from diarrhea and 160 cattle fecal samples .Feces specimens were screened for the presence of NSF E. coli and STEC by cultured onsorbitol MacConkey agar (SMAC).A total of 209 (74.6%) non-sorbitol fermenting (NSF)bacterial isolates were obtained , 69 (57.5%) from children fecal samples and 140 (87.5%) fromcattle feces . Of which 5 (4.16%) NSF E. coli isolated from children fecal samples and 38(23.75%) from cattle feces. NSF isolates were identified as Shiga toxin producing E. coli(STEC), but only 16 (10%) isolates of cattle and 2 (1.6%)isolates of children were PCR-positivefor (Stx2) gene which gave amplification bands at 346 bp using DNA marker in the interpretationof the results. Among 18 STEC studied, a total of 16 (88.8%) isolates expressed enterohemolysinon washing sheep blood agar plates.On the other hand, the study was showed that the sensitivityand specificity of PCR technique in diagnosis of STEC were 41.8% , 100% respectively, incomparison with other tests like biochemical tests, sensitivity and specificity of these tests were(100% , 86.9%) respectively.