Prevalence and antimicrobial resistance pattern of Shiga toxigenic Escherichia coli in diarrheic buffalo calves

Antimicrobial resistance profiles of Escherichia coli derived from an integrated agroforestry-livestock system in Deli Serdang Regency, Indonesia

Background and Aim

Antimicrobial resistance (AMR) has become a significant global concern. Epidemiological data do not provide a robust description of the potential risks associated with AMR in the integrated agroforestry-livestock systems in Indonesia. Thus, the present study investigated the phenotypic and multidrug resistance (MDR) profiles of Escherichia coli strains isolated from the feces of livestock raised in the agro-silvopastoral system in Deli Serdang Regency, North Sumatra Province.

Materials and Methods

A standard microbiological culture procedure was followed to isolate the organism and test antibiotic susceptibility using the Kirby-Bauer disk diffusion protocol. Furthermore, the multiple antibiotic resistance index was determined. Univariate analysis was conducted to identify the risk factors associated with AMR.

Results

The vast majority (77.5%) of livestock farmers were aged >30 years. All farmers were men and had no higher education (100% of them). The majority of the animal species managed were cattle and goats (37.5% each) and the livestock grazing pasture system (67.5%). In addition, the majority of farmers reported high antimicrobial use on their farms (87.5%). Of the samples (n = 142) analyzed, n = 70 were positive, with an overall prevalence of 44.4%. The species-specific prevalences of E. coli were 32.5%, 47.8%, and 50% in buffalo, goat, and cattle, respectively. Ampicillin and tetracyclines exhibited high resistance levels among the studied animal species. A relatively lower MDR for E. coli was associated with grazing on the pasture.

Conclusion

The findings from the current study provide baseline epidemiological information for future robust studies aimed at elucidating the drivers and patterns of AMR in agro-silvopastoral systems in the study area or elsewhere.

Resistance and virulence gene analysis and molecular typing of Escherichia coli from duck farms in Zhanjiang, China

Introduction

The widespread use of antibiotics in animal agriculture has increased the resistance of Escherichia coli, and pathogenic E. coli often harbor complex virulence factors. Antimicrobial resistance in pathogenic bacteria can cause public health problems. Correlation analyses of the resistance, virulence, and serotype data from the pathogenic bacteria found on farms and in the surrounding environment can thus provide extremely valuable data to help improve public health management.

Methods

In this investigation, we have assessed the drug resistance and virulence genes as well as the molecular typing characteristics of 30 E. coli strains isolated from duck farms in the Zhanjiang area of China. Polymerase chain reaction was used to detect the drug resistance and virulence genes as well as serotypes, and whole-genome sequencing was used to analyze the multilocus sequence typing.

Results

The detection rates for the oqxA resistance gene and fimC virulence gene were highest (93.3%, respectively). There were no correlations between the drug resistance and virulence gene numbers in the same strain. The epidemic serotype was O81 (5/24), ST3856 was an epidemic sequence type, and strains I-9 and III-6 carried 11 virulence genes. The E. coli strains from the duck farms in the Zhanjiang area were thus found to have a broad drug resistance spectrum, various virulence genes, complex serotypes, and certain pathogenicity and genetic relationship.

Discussion

Monitoring the spread of pathogenic bacteria and the provision of guidance regarding the use of antibiotics in the livestock and poultry industries will be required in the future in the Zhanjiang area.

The Diversity of Escherichia coli Pathotypes and Vaccination Strategies against This Versatile Bacterial Pathogen

Escherichia coli (E. coli) is a gram-negative bacillus and resident of the normal intestinal microbiota. However, some E. coli strains can cause diseases in humans, other mammals and birds ranging from intestinal infections, for example, diarrhea and dysentery, to extraintestinal infections, such as urinary tract infections, respiratory tract infections, meningitis, and sepsis. In terms of morbidity and mortality, pathogenic E. coli has a great impact on public health, with an economic cost of several billion dollars annually worldwide. Antibiotics are not usually used as first-line treatment for diarrheal illness caused by E. coli and in the case of bloody diarrhea, antibiotics are avoided due to the increased risk of hemolytic uremic syndrome. On the other hand, extraintestinal infections are treated with various antibiotics depending on the site of infection and susceptibility testing. Several alarming papers concerning the rising antibiotic resistance rates in E. coli strains have been published. The silent pandemic of multidrug-resistant bacteria including pathogenic E. coli that have become more difficult to treat favored prophylactic approaches such as E. coli vaccines. This review provides an overview of the pathogenesis of different pathotypes of E. coli, the virulence factors involved and updates on the major aspects of vaccine development against different E. coli pathotypes.

High Biofilm-Forming Ability and Clonal Dissemination among Colistin-Resistant Escherichia coli Isolates Recovered from Cows with Mastitis, Diarrheic Calves, and Chickens with Colibacillosis in Tunisia

BACKGROUND

Escherichia coli (E. coli) is one of the main etiological agents responsible for bovine mastitis (BM), neonatal calf diarrhea (NCD), and avian colibacillosis (AC). This study aimed to assess resistance and virulence genes content, biofilm-forming ability, phylogenetic groups, and genetic relatedness in E. coli isolates recovered from clinical cases of BM, NCD, and AC.

MATERIALS/METHODS

A total of 120 samples including samples of milk (n = 70) and feces (n = 50) from cows with BM and calves with NCD, respectively, were collected from different farms in Northern Tunisia. Bacterial isolation and identification were performed. Then, E. coli isolates were examined by disk diffusion and broth microdilution method for their antimicrobial susceptibility and biofilm-forming ability. PCR was used to detect antimicrobial resistance genes (ARGs), virulence genes (VGs), phylogenetic groups, and Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for their clonal relationship.

RESULTS

Among the 120 samples, 67 E. coli isolates (25 from BM, 22 from AC, and 20 from NCD) were collected. Overall, 83.6% of isolates were multidrug resistant. Thirty-six (53.73%) isolates were phenotypically colistin-resistant (CREC), 28.3% (19/67) were ESBL producers (ESBL-EC), and forty-nine (73.1%) formed biofilm. The bla_TEM gene was found in 73.7% (14/19) of isolates from the three diseases, whilst the bla_CTXM-g-1 gene was detected in 47.3% (9/19) of isolates, all from AC. The most common VG was the fimA gene (26/36, 72.2%), followed by aer (12/36, 33.3%), cnf1 (6/36, 16.6%), papC (4/36, 11.1%), and stx1 and stx2 genes (2/36; 5.5% for each). Phylogenetic analysis showed that isolates belonged to three groups: A (20/36; 55.5%), B2 (7/36; 19.4%), and D (6/36; 16.6%). Molecular typing by ERIC-PCR showed high genetic diversity of CREC and ESBL E. coli isolates from the three animal diseases and gave evidence of their clonal dissemination within farms in Tunisia.

CONCLUSION

The present study sheds new light on the biofilm-forming ability and clonality within CREC and ESBL-EC isolated from three different animal diseases in Tunisian farm animals.

Occurrence of Escherichia coli Pathotypes in Diarrheic Calves in a Low-Income Setting

Different E. coli pathotypes are common zoonotic agents. Some of these pathotypes cause recurrent and widespread calf diarrhea and contribute to significant economic losses in the livestock sector worldwide in addition to putting humans at risk. Here, we investigated the occurrence of E. coli pathotypes in diarrheic calves in Ethiopia kept under various calf management practices. One hundred fecal samples were collected from diarrheic calves in 98 different farms. E. coli was isolated in the samples from 99 of the diarrheic calves, and virulence genes were detected in 80% of the samples. The occurrence of E. coli pathotypes in the samples was 32% ETEC, 23% STEC, 18% STEC/ETEC, 3% EPEC, 2% EAEC, and 1% EHEC. No diarrheic calves were positive for the EIEC and DAEC pathotypes. The occurrence of pathotypes was positively associated with female calves (EPEC, p = 0.006), aged less than 2 weeks (STEC, p = 0.059), and calves fed colostrum via the hand method (STEC, p = 0.008 and EAEC, p = 0.003). This study revealed that several E. coli pathotypes occurred among calves affected with diarrhea. Moreover, the presence of a mixed STEC/ETEC pathotypes infection was present in the studied low-income setting. These findings indicate a considerable risk for the zoonotic transmission from calves to humans and the options to provide the better management for younger calves in order to reduce the economic loss.

Cangpu Oral Liquid as a Possible Alternative to Antibiotics for the Control of Undifferentiated Calf Diarrhea

Antibiotics are essential in the prevention of calf diarrhea epidemics. As more antibiotics become ineffective due to drug-resistant bacteria, attention must be directed toward alternative treatments for calf diarrhea. Natural antibiotic alternatives, such as Chinese herbal medicine, have become a research hotspot in the clinical treatment of diseases such as calf diarrhea due to their characteristics of fewer side effects, low cost, little residue, and no drug resistance. The Cangpu Oral Liquid (CP) was modified from a traditional herbal formula that had been widely used in ancient China to treat gastrointestinal diseases in animals. In order to evaluate the treatment effect of CP on neonatal calf diarrhea, a randomized controlled field trial was performed. Two hundred and forty-six diarrheal Holstein calves of 2–15 days old were selected and randomly divided into two treatment groups receiving either apramycin or CP. 101 out of 123 calves recovered from diarrhea in the CP group, whereas 77 out of 123 calves showed recovery after antibiotic therapy. There were no differences in initial weight between both groups, while the final weight was significantly different (P = 0.892, P = 0.025, respectively). The mean average daily gain (ADG) of calves (211.45 gram/day) in the CP group was significantly higher compared to the antibiotic group (164.56 gram/day) (P = 0.001). The CP group also showed a shorter recovery time from diarrhea (3.90 days vs. 6.62 days, P = 0.001). The current results indicate that the CP has a beneficial clinical effect on the treatment of diarrhea in neonatal calves and is an effective alternative treatment option.

Pathotyping and antimicrobial susceptibility testing of Escherichia coli isolates from neonatal calves

Neonatal calf mortality is a major concern to livestock sector worldwide. Neonatal calf diarrhoea (NCD), an acute severe condition causes morbidity and mortality in calves. Amongst various pathogens involved in NCD, E. coli is considered as one of the major causes. The study was targeted to characterize E. coli isolates from neonatal calves for diarrhoeagenic Escherichia coli (DEC) types (pathotyping), antimicrobial resistance (AMR) profiling and to correlate with epidemiological parameters. From neonates, a total of 113 faecal samples were collected, out of that 308, lactose fermenting colonies were confirmed as E. coli. Pathotypable isolates (12.3%) were represented by STEC (6.1%), EPEC (2.9%), ETEC (1.9%), EAEC (0.9%) and EHEC (0.3%). Occurrence of STEC was more in non-diarrhoeic calves, whereas ETEC was observed more in diarrhoeic calves. EPEC occurrence was observed in both diarrhoeic and non-diarrhoeic calves. Fishers extract test showed no significant association for occurrence of DEC types to type of dairies, health status, species, breed, age and sex of neonatal calves. Two hundred and eighty isolates were tested for antimicrobial susceptibility. The isolates showed maximum resistance towards ampicillin (55.4%) followed by tetracycline (54.3%), while minimum resistance was observed towards meropenem (2.5%). Multidrug resistant E. coli isolates were found to be 139 (49.6%), and Extended-spectrum beta-lactamase (ESBL) producers were 120 (42.9%). DEC pathotypes like STEC, ETEC, EHEC and EAEC that are also multidrug resistant present in neonatal calves have zoonotic potential and hence are of public health significance.

RETRACTED ARTICLE: Molecular detection of pathogenic Escherichia coli strains and their antibiogram associated with risk factors from diarrheic calves in Jimma Ethiopia

Diarrheagenic Escherichia coli are a number of pathogenic E. coli strains that cause diarrheal infection both in animal and human hosts due to their virulence factors. A cross sectional study was conducted between November, 2016 and April, 2017 to isolate and molecularly detect pathogenic E. coli from diarrheic calves to determine the pathogenic strains, antibiogram and associated risk factors in Jimma town. Purposive sampling technique was used to collect 112 fecal samples from diarrheic calves. Conventional culture and biochemical methods were conducted to isolate E. coli isolates. Molecular method was followed to identify virulence factors of pathogenic E. coli strains. Antimicrobial sensitivity patterns of the isolates were tested using the Kirby-Bauer disk diffusion method. A structured questionnaire was also used to collect information from dairy farms and socio-demographic data. The overall isolation rate of E. coli in calves was 51.8% (58/112) (95% CI 42.0-61.0). The occurrence of the bacterium differed significantly by age, colostrum feeding time, amount of milk given per time and navel treatment (P < 0.05). Multivariable analysis revealed that the odds of being infected was significantly highest in calves which fed 1-1.5 L amount of milk per a time (OR 5.38, 95% CI 1.66-17.45, P = 0.005). The overall virulence genes detection rate was 53.5% (95% CI 40.0-67.0). Eleven (19.6%) of eaeA, 6 (10.7%) of Stx1 and 13 (23.2%) of Stx2 genes were detected from calves isolates. Except ciprofloxacillin, all isolates were resistant to at least one drug. Multi drug resistance was recorded in 68.0% (38/56) of calves isolates. Neomycin, 83.3% (25/30), followed by amoxicillin, 53.3% (16/30) were the highest resisted virulence genes. The study demonstrated considerable isolation rate, multiple antimicrobial resistant isolates and high resistant virulent genes in diarrheic calves. It also indicated that the potential importance of calves as source of pathogenic E. coli strains and resistant genes for human diarrhea infection. Improving the hygienic practice of farms and wise use of antimicrobials could help to reduce the occurrence of pathogenic E. coli in farms. Hence, further studies are needed to describe all virulent factors and serotypes associated with the emergence of drug resistant pathogenic E. coli strains in calves.

Detection of novel sequence types and zoonotic transmission potentiality among strains of Shiga toxigenic Escherichia coli (STEC) from dairy calves, animal handlers and associated environments

Shiga toxigenic Escherichia coli (STEC) is one of the most important food-borne zoonotic bacterial pathogens responsible for causing gastrointestinal infections, haemorrhagic colitis and haemolytic uremic syndrome. The present study was aimed to isolate and characterize STEC from neonatal dairy calves, animal handlers and their surrounding environment and to establish the genetic relationship among isolates by multilocus sequence typing (MLST). A total number of 115 samples were collected and processed for the isolation of E. coli. The occurrence rate of E. coli was 92.2% (106/115), of which, 18 were typed as STEC. Antibacterial susceptibility analysis revealed 11 (61.1%) strains as multiple drug-resistant (MDR). MLST analysis has delineated 16 sequence types (STs) including nine novel STs. Among STs, ST58 dominated with three strains and was recovered from the environment and neonatal calves. Strains from neonatal calves and humans showed genetic relatedness with significant bootstrap support values indicative of zoonotic transmission potentiality. Analysis of 211 global isolates belonging to 61 STs indicated predominant STs (ST 21, ST 33 and ST 3416) that can be either host-specific (ST 33 and ST 3416) or can be shared among human and bovine hosts (ST 21). The MLST analysis indicates genetic relatedness among isolates and the results predispose inter-host transmission and zoonotic spread.

Molecular Analysis of Antimicrobial Resistance among Enterobacteriaceae Isolated from Diarrhoeic Calves in Egypt

Simple Summary

Bacterial antimicrobial resistance is a serious global health challenge. This study investigated the occurrence of major antimicrobial resistance genes, including integrons, ß-lactamases, and florfenicol in Enterobacteriaceae that were isolated from diarrhoeic calves in Egypt. From 120 calves, 149 isolates of bacteria were recovered, identified, and screened phenotypically against 12 antimicrobials, and molecularly for the presence of the resistance determinants of integrons, ß-lactamases and florfenicol. The findings revealed that 24.8% of the isolates exhibited multidrug resistance. Escherichia coli was found to be the most prevalent multidrug resistant species. Class 1 integrons, bla_TEM, and floR genes were detected at incidence rates of 18.8%, 24.8%, and 1.3%, respectively, whereas class 2 integrons and bla_CTX-M were not detected in any isolates. The higher incidence of the antimicrobial resistance genes indicate the importance of regular monitoring of the antibiotic susceptibilities of isolated bacteria to minimise the risk of human exposure to pathogens that are resistant to antimicrobials.

Abstract

The present study was designed to investigate the presence of genes that conferred resistance to antimicrobials among Enterobacteriaceae that were isolated from diarrhoeic calves. A total of 120 faecal samples were collected from diarrhoeic calves that were raised in Kafr El-Sheikh governorate, Egypt. The samples were screened for Enterobacteriaceae. A total of 149 isolates of bacteria were recovered and identified; Escherichia coli was found to be the most overwhelming species, followed by Citrobacter diversus, Shigella spp., Serratia spp., Providencia spp., Enterobacter spp., Klebsiella pneumoniae, Proteus spp., Klebsiella oxytoca, and Morganella morganii. All isolates were tested for susceptibility to 12 antimicrobials; resistant and intermediately resistant strains were screened by conventional polymerase chain reaction for the presence of antimicrobial resistance genes. Of the 149 isolates, 37 (24.8%) exhibited multidrug resistant phenotypes. The most prevalent multidrug resistant species were E. coli, C. diversus, Serratia spp., K. pneumoniae, Shigella spp., Providencia spp., and K. oxytoca. Class 1 integrons were detected in 28 (18.8%) isolates. All isolates were negative for class 2 integrons. The bla_TEM gene was identified in 37 (24.8%) isolates, whereas no isolates carried the bla_CTX-M gene_. The florfenicol gene (floR) was detected in two bacterial isolates (1.3%). The findings of this study reveal that calves may act as potential reservoirs of multidrug resistant bacteria that can be easily transmitted to humans.

Genes Encoding the Virulence and the Antimicrobial Resistance in Enterotoxigenic and Shiga-Toxigenic E. coli Isolated from Diarrheic Calves

Calf diarrhea is one of the considerable infectious diseases in calves, which results in tremendous economic losses globally. To determine the prevalence of Shiga-toxigenic E. coli (STEC) and Enterotoxigenic E. coli (ETEC) incriminated in calf diarrhea, with special reference to Shiga- toxins genes (stx1 and stx2) and enterotoxins genes (lt and sta) that govern their pathogenesis, as well as the virulence genes; eaeA (intimin) and f41(fimbrial adhesion), and the screening of their antibiogram and antimicrobial resistance genes; aadB, sul1, and bla-TEM, a total of 274 fecal samples were collected (April 2018–Feb 2019) from diarrheic calves at different farms in El-Sharqia Governorate, Egypt. The bacteriological examination revealed that the prevalence of E. coli in diarrheic calves was 28.8%. The serotyping of the isolated E. coli revealed 7 serogroups; O₂₆, O₁₂₈, O₁₁₁, O₁₂₅, O₄₅, O₁₁₉ and O₉₁. Furthermore, the Congo red binding test was carried out, where 89.8% of the examined strains (n = 71) were positive. The antibiogram of the isolated strains was investigated; the majority of E. coli serotypes exhibit multidrug resistance (MDR) to four antimicrobial agents; neomycin, gentamycin, streptomycin, and amikacin. Polymerase chain reaction (PCR) was used to detect the prevalence of the virulence genes; stx1, stx2 lt, sta, f41 and eaeA, as well as the antimicrobial resistance genes; aadB, sul1, and bla-TEM. The prevalence of STEC was 20.2% (n = 16), while the prevalence of ETEC was 30.4% (n = 24). Briefly, the Shiga toxins genes; stx1 and stx2, are the most prevalent virulence genes associated with STEC, which are responsible for the pathogenesis of the disease and helped by the intimin gene (eaeA). In addition, the lt gene is the most prevalent enterotoxin gene accompanied by the ETEC strains, either alone or in combination with sta and/or f41 genes. The majority of pathogenic E. coli incriminated in calf diarrhea possesses the aadB resistance gene, followed by the sul1 gene. Enrofloxacin, florfenicol, amoxicillin-clavulanic acid, and ampicillin-sulbactam, are the most effective antimicrobial agents against the isolated STEC and ETEC strains.