Escherichia coli is present in the normal intestinal flora but some strains can cause intestinal and extraintestinal diseases, and research on its presence in food of animal origin is in the interests of public health. This study was designed to characterise E. coli strains according to their origin, their carriage of virulence genes specific for certain pathogroups, and phylogenetic group affiliation.

Introduction: Avian pathogenic Escherichia coli (APEC) is a leading cause of extraintestinal infection and heavy economic losses. Imparting immunity after vaccination with live attenuated strain vaccination is an ideal strategy for infection control. This study considers an FtsK knockout mutant strain as a candidate. Material and Methods: An FtsK knockout mutant of APEC strain E058 was constructed and the pathogenicity of the mutant and wild-type strains was further evaluated in chickens. Results: The 50% lethal doses of each strain for one-day-old specific-pathogen-free (SPF) chickens challenged experimentally via trachea were 105.5 and 107.0 colony-forming units (CFU) respectively. Chickens challenged with the wild-type strain exhibited typical signs and lesions of avian colibacillosis, while those inoculated with the mutant strain showed mild pericarditis and pulmonary congestion. The growth rate of the FtsK mutant strain was much slower than the wild-type strain in the heart, spleen, liver, and lung of infected chickens. Conclusion: These results indicated that the APEC FtsK mutant can be attenuated for chickens, and that this mutant has the potential for the development of an APEC vaccine.

Escherichia coli is a widespread environmental pathogen frequently causing dairy cow mastitis. This bacterium is particularly capable of acquiring antimicrobial resistance, which can have severe impacts on animal food safety and human health. The objective of the study was to investigate antimicrobial resistance and genetic correlations of E. coli from dairy cow mastitis cases in northern China.

A conclusive study was conducted for preparation and evaluation of combinedinactivated entero-4 vaccine containing bovine rotavirus (BRV), bovine coronavirus(BCV), E. coli K99 and toxoid of C. perfringens type "C". Laboratory and field evaluations were conducted on laboratory animals, calves and late pregnant cows with monitoring the active and passive antibodies in vaccinated cows and their offspring respectively. Laboratory evaluation proved purity, safety and high efficacy of the vaccine without interference between different vaccine ingredients. Field evaluation gave satisfactory results when pregnant cows vaccinated at late stage of pregnancy with high neutralizing antibody titers against BRV, BCV and C. perfringens as well as high E. coli agglutinating titers. Maternal immunity passively protected offspring during the critical period of age and remained protected till the end of sampling time (30th day post parturition).

Anualmente o tráfico de animais silvestres retira milhões de aves da natureza. Os cardeais (Paroaria coronata) e cardeais-do-nordeste (Paroaria dominicana) estão incluídos entre as espécies de aves mais traficadas. A microbiota cloacal de passeriformes de vida livre é composta principalmente por bacilos e cocos gram-positivos, já os bacilos gram-negativos predominam em aves de cativeiro. Em situações de estresse e baixa de imunidade as bactérias gram-negativas podem causar infecções oportunistas. O presente trabalho identificou bactérias da microbiota da cloaca de 49 espécimes de P. coronata e P. dominicana apreendidas do tráfico de animais silvestres em São Paulo (SP). Foram isoladas treze espécies de bactérias gram-negativas, incluindo Salmonella spp. e Pseudomonas aeruginosa. A maior frequência de ocorrência foi de Escherichia coli, identificada em 42/49 (85,7%) das amostras fecais. Dentre os isolados de E. coli, 21/42 pertenciam aos grupos filogenéticos B2 e D, relacionados a estirpes patogênicas que causam doença extraintestinal em humanos. Klebsiella pneumoniae foi isolada em 28/49 (57,1%) das amostras. Esses resultados reforçam que as condições estressantes a que esses animais são submetidos em situações de tráfico, incluindo o contato com humanos, podem favorecer a colonização da microbiota cloacal das aves por patógenos, o que representa um risco para a sua reintrodução na natureza considerando-se o possível contato com humanos e outros animais.

Objective: The increase and prevalence of multidrug-resistant bacteria in livestock animals are serious public health concerns. This study aimed to identify the presence of the blaTEM gene in extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolated from rectal swabs of apparently healthy pigs in Malang District, East Java, Indonesia. Materials and Methods: A total of 120 rectal swab samples were collected from the pigs. The rectal swabs were screened for the presence of E. coli using standard microbiological identifi¬cation procedures. The Kirby–Bauer disk diffusion method identified multidrug-resistant E. coli. Five different classes of antibiotics were used to identify multidrug-resistant isolates, including Ciprofloxacin, Trimethoprim, Tetracycline, Streptomycin, and Aztreonam. Multidrug-resistant E. coli isolates were characterized for the presence of ESBL using double-disk synergy test methods. The presence of blaTEM genes was determined using polymerase chain reaction methods. Results: The results of this study indicated that 107 (89.2%) out of 120 samples analyzed were positive for E. coli isolates. A total of 32 (29.9%) E. coli isolates were identified to be multidrug-re¬sistant and further subjected to molecular testing. The molecular analysis revealed (5; 15.6%) E. coli isolates to harbor the blaTEM gene. Conclusion: The results of this study revealed that pigs and products of pork origin must be considered a source of transmission of ESBL-producing E. coli to public health important under the food chain. [J Adv Vet Anim Res 2022; 9(3.000): 447-452]

Objective: The study was carried out for molecular characterization and antibiotic resistance anal¬ysis of Escherichia coli isolated from different turkey farms in Dinajpur, Bangladesh. Materials and methods: A total of 45 samples comprising feces (n = 23) and cloacal swabs (n = 22) were collected randomly from turkeys. The samples were subjected to isolation and identification of E. coli by cultural and biochemical characteristics, followed by polymerase chain reaction and sequencing. An antibiogram of the isolated E. coli isolates was carried out by following the Kirby Bauer disk diffusion method. Results: Out of the 45 samples, 28 (62.21%) were positive for E. coli, of which 16 (35.55%) fecal samples were positive and 12 (26.66%) cloacal swabs were positive. The antibiotic sensitivity analysis revealed that all the E. coli isolates were 100% sensitive to levofloxacin, norfloxacin, neo¬mycin, gentamicin, and nitrofurantoin. On the other hand, all the isolates were 100% resistant to amoxicillin, azithromycin, erythromycin, tetracycline, bacitracin, cephalexin, nalidixic acid, van¬comycin, methicilin, piperacillin, pefloxacin, novobiocin, cefepime, trimethoprim, netilmicin, and aztreonam. Conclusion: This studys results uncover the occurrence and antibiotic resistance pattern of E. coli in the study areas turkeys. [J Adv Vet Anim Res 2021; 8(1.000): 64-69]

Objective: The case study describes the cause of an increase in mortality rates among 35-day-old broilers that developed respiratory distress and bloody diarrhea on a farm in Malaysia. Materials and Methods: The organ samples were subjected to laboratory testing and postmortem inspection. Escherichia (E.) coli and Mycoplasma (M.) gallisepticum were detected using bacterial isolation and molecular diagnostics using polymerase chain reaction. Results: Chickens with the infection had widespread fibrin buildup in several organs and hemorrhages on the duodenal mucosa. Additional histology and laboratory analysis of organ samples revealed infection with M. gallisepticum, E. coli, and enteric Eimeria spp., all of which are consistent with complex chronic respiratory disease (CCRD) associated with coccidiosis. Tylosin tartrate 20% (w/w) (2.5 gm/l) was prescribed for 1 week along with a combination of the broad-spectrum bacteriostatic drug streptomycin (25 mg/kg) and coccidiostat (2 gm/5 l). Conclusion: CCRD and coccidiosis are both infectious diseases that can infect chicken flocks, resulting in production losses and carcass quality degradation. Early disease detection and proper treatment should be provided promptly, and tight farm biosecurity should be implemented to prevent chicken mortality on the farm, as was achieved successfully. [J Adv Vet Anim Res 2021; 8(4.000): 576-580]

Objective: The effect of seasonality needs to be considered in designing future studies because global warming has caused a rise in ambient temperatures. The objective of the present study is to investigate the effect of high ambient temperatures on fecal score and fecal microflora in dairy cows during summer. Materials and Methods: During the 7 days before the sampling of feces, the daily mean tempera¬tures were 19.9°C in early summer and more than 27.5°C in late summer. Fecal samples were collected from the rectum of cows and the fecal score was evaluated on a 4-point scale. The equalized samples were used to extract the genomic deoxyribonucleic acid (DNA) of the bacteria (Escherichia coli, Salmonella, Lactobacillus, and Bifidobacterium). Results: There was no significant difference in fecal scores between the sampling times in early and late summer. In the populations of the bacteria, there was no significant difference between sampling days in the DNA level of Salmonella, and E. coli in late summer increased to more than three times the level in early summer. However, both levels of Lactobacillus and Bifidobacterium in early summer significantly decreased after 2 months. Conclusion: These data suggest that the increase in temperature in late summer may adversely affect the populations of bacteria in the intestinal environment of dairy cows. In addition, the method used in the present study was sufficient to evaluate the changes in internal and external environmental conditions of dairy cattle. [J Adv Vet Anim Res 2021; 8(2.000): 307-311]

Objective: The investigation was undertaken to measure the epidemiological features and antimicrobial sensitivity patterns of Escherichia coli among different breeds of goats in Cox's Bazar, Bangladesh.Materials and methods: A total of 150 rectal swab samples were collected from selected goats. The samples were subjected for the isolation of E. coli through a series of conventional bacteriological and biochemical techniques. The isolated E. coli were used for assessing antimicrobial susceptibility by disk diffusion method. Besides prevalence study, nine risk factors were studied; the risk factors were- breed, age, hygienic status, sex, history of recent transportation, season, diarrhea, body condition score, and source of drinking water. Results: The overall prevalence of E. coli in the rectal swabs of goats was 52% (n=78/150). The young goats were highly susceptible (65.0%; n=52/80) to E. coli infection as compared to adults (37.1%; n=26/70). The prevalence was higher (66.7%; n=42/63) in the goats that was reared in poor hygienic condition as compared to the goats that were reared under good hygienic condition. The influence of the source of drinking water on E. coli prevalence was found to be higher both in pond (63.6%; n=7/11) and municipality (61.4%; n=51/83) supplied water as compared to tube-well (35.7%; n=20/56). The goats having recent transportation history showed higher prevalence (64.8%; n=35/54). The prevalence was higher in diarrheic goats (62.0%; n=49/79) than non-diarrheic goats. Among the E. coli isolates (n=78), 31 were found to be multidrug resistant (MDR) to 3 to 8 subclasses of antimicrobials.Conclusion: Presence of MDR E. coli in the studied goats suggest the probable acquisition, development and transmission of MDR E. coli through a number of influencing factors to other animals and potentially to human. [J Adv Vet Anim Res 2016; 3(2.000): 166-172]