Phage-mediated dissemination of virulence factors in pathogenic bacteria facilitated by antibiotic growth promoters in animals: a perspective

AbstractAddition of sub-therapeutic antibiotics to the feed of food-producing animals for growth promotion and disease prevention has become a common agricultural practice in many countries. The emergence of antibiotic-resistant pathogens is a looming concern associated with the use of antibiotic growth promoters (AGPs) around the world. In addition, some studies have shown that AGPs may not only affect antibiotic resistance but may also stimulate the dissemination of virulence factors via bacteriophages. Although only a few studies are currently available in the literature regarding this topic, in this article we endeavor to provide a perspective about how AGPs would impact the transmission of virulence factors by horizontal gene transfer via phages in a few pathogenic bacterial species significant to livestock production.

Download Full-text

Alteration of the Ileal Microbiota of Weanling Piglets by the Growth-Promoting Antibiotic Chlortetracycline

Applied and Environmental Microbiology ◽

10.1128/aem.02220-08 ◽

2009 ◽

Vol 75 (17) ◽

pp. 5489-5495 ◽

Cited By ~ 58

Author(s):

Elizabeth Rettedal ◽

Sï¿½bastien Vilain ◽

Stacy Lindblom ◽

Kelly Lehnert ◽

Clay Scofield ◽

...

Keyword(s):

Growth Promotion ◽

Pcr Amplification ◽

Growing Pigs ◽

Rrna Gene ◽

Significant Shift ◽

Growth Promoters ◽

Antibiotic Resistant ◽

Operational Taxonomic Units ◽

Bacterial Microbiota ◽

Antibiotic Growth Promoters

ABSTRACT Antibiotics such as chlortetracycline (CTC) have been used to promote growth of pigs for decades, but concerns over increased antibiotic-resistant infections in humans have prompted the development of alternative strategies. Developing alternatives to antibiotic growth promoters (AGPs) could be informed by information on the mechanisms of growth promotion, notably, how AGPs affect the microbial populations of the gastrointestinal tract. Pigs from three sows were aseptically delivered by cesarean section. Six piglets were distributed to each of two foster mothers until weaning, when piglets were fed a diet with or without 50 mg/kg CTC for 2 weeks. The ileal bacterial microbiota was characterized by using a cultivation-independent approach based on DNA extraction, PCR amplification, cloning, and sequencing of the 16S rRNA gene pool. The ileal and mucosal communities of these growing pigs were dominated by Lactobacillus bacteria, various members of the family Clostridiaceae, and members of the poorly known genus Turicibacter. Overall, CTC treatment resulted in three shifts: a decrease in L actobacillus johnsonii, an increase in L. amylovorus, and a decrease in Turicibacter phylotypes. The composition of the microbiota varied considerably between individual pigs, as revealed by shared operational taxonomic units (OTUs) and similarity (SONS) analysis (θYC values). While the observed variation between untreated pigs obscured the possible effect of CTC, ∫-LIBSHUFF and SONS analyses of pooled libraries indicated a significant shift due to CTC in both the lumen and the mucosa, with some OTUs unique to either treated or control ileum. DOTUR analysis revealed little overlap between control and treated communities at the 3% difference level, indicating unique ileal communities in the presence of CTC.

Download Full-text

Antibiotic Resistance Gene Diversity and Virulence Gene Diversity Are Correlated in Human Gut and Environmental Microbiomes

mSphere ◽

10.1128/msphere.00135-19 ◽

2019 ◽

Vol 4 (3) ◽

Cited By ~ 12

Author(s):

Pedro Escudeiro ◽

Joël Pothier ◽

Francisco Dionisio ◽

Teresa Nogueira

Keyword(s):

Antibiotic Resistance ◽

Comparative Study ◽

Microbial Communities ◽

Pathogenic Bacteria ◽

Gene Diversity ◽

Bacterial Species ◽

Human Populations ◽

Virulence Determinants ◽

Human Gut ◽

The World

ABSTRACT Human beings have used large amounts of antibiotics, not only in medical contexts but also, for example, as growth factors in agriculture and livestock, resulting in the contamination of the environment. Even when pathogenic bacteria are the targets of antibiotics, hundreds of nonpathogenic bacterial species are affected as well. Therefore, both pathogenic and nonpathogenic bacteria have gradually become resistant to antibiotics. We tested whether there is still cooccurrence of resistance and virulence determinants. We performed a comparative study of environmental and human gut metagenomes from different individuals and from distinct human populations across the world. We found a great diversity of antibiotic resistance determinants (AR diversity [ARd]) and virulence factors (VF diversity [VFd]) in metagenomes. Importantly there is a correlation between ARd and VFd, even after correcting for protein family richness. In the human gut, there are less ARd and VFd than in more diversified environments, and yet correlations between the ARd and VFd are stronger. They can vary from very high in Malawi, where antibiotic consumption is unattended, to nonexistent in the uncontacted Amerindian population. We conclude that there is cooccurrence of resistance and virulence determinants in human gut microbiomes, suggesting a possible coselective mechanism. IMPORTANCE Every year, thousands of tons of antibiotics are used, not only in human and animal health but also as growth promoters in livestock. Consequently, during the last 75 years, antibiotic-resistant bacterial strains have been selected in human and environmental microbial communities. This implies that, even when pathogenic bacteria are the targets of antibiotics, hundreds of nonpathogenic bacterial species are also affected. Here, we performed a comparative study of environmental and human gut microbial communities issuing from different individuals and from distinct human populations across the world. We found that antibiotic resistance and pathogenicity are correlated and speculate that, by selecting for resistant bacteria, we may be selecting for more virulent strains as a side effect of antimicrobial therapy.

Download Full-text

Impact of Fertilizing with Raw or Anaerobically Digested Sewage Sludge on the Abundance of Antibiotic-Resistant Coliforms, Antibiotic Resistance Genes, and Pathogenic Bacteria in Soil and on Vegetables at Harvest

Applied and Environmental Microbiology ◽

10.1128/aem.02389-14 ◽

2014 ◽

Vol 80 (22) ◽

pp. 6898-6907 ◽

Cited By ~ 93

Author(s):

Teddie O. Rahube ◽

Romain Marti ◽

Andrew Scott ◽

Yuan-Ching Tien ◽

Roger Murray ◽

...

Keyword(s):

Antibiotic Resistance ◽

Sewage Sludge ◽

Resistance Genes ◽

Pathogenic Bacteria ◽

Antibiotic Resistance Genes ◽

Coliform Bacteria ◽

Agricultural Practice ◽

Antibiotic Resistant ◽

Human Waste ◽

Class B

ABSTRACTThe consumption of crops fertilized with human waste represents a potential route of exposure to antibiotic-resistant fecal bacteria. The present study evaluated the abundance of bacteria and antibiotic resistance genes by using both culture-dependent and molecular methods. Various vegetables (lettuce, carrots, radish, and tomatoes) were sown into field plots fertilized inorganically or with class B biosolids or untreated municipal sewage sludge and harvested when of marketable quality. Analysis of viable pathogenic bacteria or antibiotic-resistant coliform bacteria by plate counts did not reveal significant treatment effects of fertilization with class B biosolids or untreated sewage sludge on the vegetables. Numerous targeted genes associated with antibiotic resistance and mobile genetic elements were detected by PCR in soil and on vegetables at harvest from plots that received no organic amendment. However, in the season of application, vegetables harvested from plots treated with either material carried gene targets not detected in the absence of amendment. Several gene targets evaluated by using quantitative PCR (qPCR) were considerably more abundant on vegetables harvested from sewage sludge-treated plots than on vegetables from control plots in the season of application, whereas vegetables harvested the following year revealed no treatment effect. Overall, the results of the present study suggest that producing vegetable crops in ground fertilized with human waste without appropriate delay or pretreatment will result in an additional burden of antibiotic resistance genes on harvested crops. Managing human exposure to antibiotic resistance genes carried in human waste must be undertaken through judicious agricultural practice.

Download Full-text

Development of antimicrobial therapy methods to overcome the antibiotic resistance of Acinetobacter baumannii

Acta Naturae ◽

10.32607/actanaturae.10955 ◽

2020 ◽

Vol 12 (3) ◽

pp. 34-45

Author(s):

Olga V. Kisil ◽

Tatiana A. Efimenko ◽

Nina I. Gabrielyan ◽

Olga V. Efremenkova

Keyword(s):

Antibiotic Resistance ◽

Acinetobacter Baumannii ◽

Pathogenic Bacteria ◽

Uv Light ◽

Outer Membrane Proteins ◽

World Health ◽

Antibiotic Resistant ◽

The World ◽

Clinically Significant ◽

Health Organization

The spread of antibiotic resistance among pathogens represents a threat to human health around the world. In 2017, the World Health Organization published a list of 12 top-priority antibiotic-resistant pathogenic bacteria for which new effective antibiotics or new ways of treating the infections caused by them are needed. This review focuses on Acinetobacter baumannii, one of these top-priority pathogens. The pathogenic bacterium A. baumannii is one of the most frequently encountered infectious agents in the world; its clinically significant features include resistance to UV light, drying, disinfectants, and antibiotics. This review looks at the various attempts that have been made to tackle the problem of drug resistance relating to A. baumannii variants without the use of antibiotics. The potential of bacteriophages and antimicrobial peptides in the treatment of infections caused by A. baumannii in both planktonic and biofilm form is assessed. Such topics as research into the development of vaccines based on the outer membrane proteins of A. baumannii and the use of silver nanoparticles, as well as photodynamic and chelate therapy, are also covered.

Download Full-text

Bacteria and Their Antibiotic Resistance Profiles in Ambient Air in Accra, Ghana, February 2020: A Cross-Sectional Study

Tropical Medicine and Infectious Disease ◽

10.3390/tropicalmed6030110 ◽

2021 ◽

Vol 6 (3) ◽

pp. 110

Author(s):

Godfred Saviour Kudjo Azaglo ◽

Mohammed Khogali ◽

Katrina Hann ◽

John Alexis Pwamang ◽

Emmanuel Appoh ◽

...

Keyword(s):

Antibiotic Resistance ◽

Pathogenic Bacteria ◽

Ambient Air ◽

Cross Sectional Study ◽

Bacillus Species ◽

Resistant Bacteria ◽

Cross Sectional ◽

Antibiotic Resistant ◽

Bacterial Counts ◽

Inappropriate Use

Inappropriate use of antibiotics has led to the presence of antibiotic-resistant bacteria in ambient air. There is no published information about the presence and resistance profiles of bacteria in ambient air in Ghana. We evaluated the presence and antibiotic resistance profiles of selected bacterial, environmental and meteorological characteristics and airborne bacterial counts in 12 active air quality monitoring sites (seven roadside, two industrial and three residential) in Accra in February 2020. Roadside sites had the highest median temperature, relative humidity, wind speed and PM10 concentrations, and median airborne bacterial counts in roadside sites (115,000 CFU/m3) were higher compared with industrial (35,150 CFU/m3) and residential sites (1210 CFU/m3). Bacillus species were isolated in all samples and none were antibiotic resistant. There were, however, Pseudomonas aeruginosa, Escherichia coli, Pseudomonas species, non-hemolytic Streptococci, Coliforms and Staphylococci species, of which six (50%) showed mono-resistance or multidrug resistance to four antibiotics (penicillin, ampicillin, ciprofloxacin and ceftriaxone). There was a positive correlation between PM10 concentrations and airborne bacterial counts (rs = 0.72), but no correlations were found between PM10 concentrations and the pathogenic bacteria nor their antibiotic resistance. We call for the expansion of surveillance of ambient air to other cities of Ghana to obtain nationally representative information.

Download Full-text

Effects of butyric acid, mannanoligosaccharide (MOS) and avilamycin on performance and small intestine morphology of broiler chickens

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200030726 ◽

2009 ◽

Vol 2009 ◽

pp. 233-233

Author(s):

S N Mousavi ◽

M Shivazad ◽

N Ghazvini

Keyword(s):

Fatty Acids ◽

Antibiotic Resistance ◽

Small Intestine ◽

Butyric Acid ◽

Broiler Chickens ◽

Short Chain Fatty Acids ◽

Growth Promoters ◽

Potential Alternative ◽

Antibiotic Growth Promoters ◽

Public Scrutiny

The subtherapeutic use of antibiotics in animals has been under scientific and public scrutiny as antibiotic growth promoters (AGP) have been linked to the development of antibiotic resistance in bacteria, which poses a threat to human health (Smith et al., 2003). Short chain fatty acids such as butyrate are considered as potential alternative to AGP, In addition to its bactericidal activity; butyrate appears to play a role in development of the intestinal epithelium (Leeson 2005). Prebiotics (e.g. mannanoligosaccharides, MOS) are nondigestible feed ingredients that can selectively stimulate growth or metabolic activity of a limited number of intestinal microorganisms (Gibson and Roberfroid, 1995). This study was, therefore, conducted to investigate effectiveness of mannanoligosaccharides and butyric acid as potential alternatives to AGP in broilers.

Download Full-text

Genome Assessment of Antibiotic Resistance Genes in Probiotic Bacteria and a Literature Review

10.21203/rs.3.rs-254514/v1 ◽

2021 ◽

Author(s):

Mehdi Fatahi-Bafghi ◽

Sara Naseri ◽

Ali Alizehi

Keyword(s):

Antibiotic Resistance ◽

Genome Sequence ◽

Resistance Genes ◽

Pathogenic Bacteria ◽

Antibiotic Resistance Genes ◽

Probiotic Bacteria ◽

Whole Genome Sequence ◽

Probiotic Properties ◽

Antibiotic Resistant ◽

To Come

Abstract Having various clinical applications, probiotic bacteria are currently used in the diet. There are reports of antibiotic resistance genes (ARGs) in these bacteria that can be transferred to other microflora and pathogenic bacteria. The aim of the study is to examine whole-genome sequence analysis in bacteria with probiotic properties. Moreover, this study follows existing issues about the importance and presence of ARGs in these bacteria the dangers of which may affect human health in the years to come. In the present study, 126 complete probiotic bacterial genomes were collected and analysed for ARGs. The results of the study shows there are various antibiotic resistant genes of in these bacteria some of which can be transmitted to other bacteria. We propose microorganisms be applied as a probiotic element in various types of products, antibiogram be conducted for a large number of antibiotics and analysis of complete genome sequence for ARGs prediction.

Download Full-text

Antimicrobial Resistance of Bacterial Flora Associated with Bovine Products in South Africa

Journal of Food Protection ◽

10.4315/0362-028x-62.6.615 ◽

1999 ◽

Vol 62 (6) ◽

pp. 615-618 ◽

Cited By ~ 15

Author(s):

THUREYAH MANIE ◽

VOLKER S. BRÖZEL ◽

WALTER J. VEITH ◽

PIETER A. GOUWS

Keyword(s):

South Africa ◽

Antibiotic Resistance ◽

Pathogenic Bacteria ◽

Bacterial Flora ◽

Resistant Bacteria ◽

Antibiotic Resistant ◽

Selective Pressures ◽

Unpasteurized Milk ◽

Plate Counts ◽

Resistance To Penicillin

The administration of subtherapeutic doses of antibiotics to livestock introduces selective pressures that may lead to the emergence and dissemination of resistant bacteria. This study determined the antibiotic-resistance spectra of the microbial flora found on freshly slaughtered and retail beef and in unpasteurized and pasteurized packaged milk. Staphylococci, Enterobacteriaceae, and isolates from total aerobic plate counts were tested for resistance to vancomycin, streptomycin, methicillin, tetracycline, and gentamicin using the disc diffusion susceptibility test and resistance to penicillin was determined by using oxacillin. A larger proportion of resistance to most antibiotics, except for vancomycin, was displayed by isolates from abattoir samples. The incidence of multiple antibiotic resistance (MAR) pathogenic bacteria is also higher in the abattoir. Resistance genes lost because of lack of selective pressure or resistant flora being replaced by more sensitive flora during processing is the reason for the lower incidence of MAR pathogenic bacteria among retail samples. These resistant bacteria can be transferred to humans through the consumption of rare or raw beef and unpasteurized milk, thus rendering the resultant food-related infections difficult to treat. The present findings clearly demonstrate that antibiotic-resistant bacteria in beef and milk pose a serious problem in South Africa.

Download Full-text

Two resistance nodulation division-family efflux pumps inChromobacteriumspecies and their role in antibiotic resistance and tolerance

10.1101/562140 ◽

2019 ◽

Author(s):

Saida Benomar ◽

Kara C Evans ◽

Robert L Unckless ◽

Josephine R Chandler

Keyword(s):

Antibiotic Resistance ◽

Efflux Pump ◽

Bacterial Species ◽

Efflux Pumps ◽

Resistance Mechanisms ◽

Antibiotic Resistant ◽

Burkholderia Thailandensis ◽

New Information ◽

Resistance Nodulation Division ◽

Culture Growth

ABSTRACTVery little is known of the antibiotic resistance mechanisms of members of theChromobacteriumgenus. In previous studies ofChromobacterium subtsugae(formerlyC. violaceum) strain CV017, we identified a resistance nodulation division (RND)-family efflux pump (CdeAB-OprM). Here, we show thecdeAB-oprMgenes are widely distributed in members of theChromobacteriumgenus. We use antimicrobial susceptibility testing with a CV017cdeAB-oprMmutant to show the products of these genes confers resistance to a variety of antibiotics including ciprofloxacin, a clinically important antibiotic. We also identified a related RND-family pump,cseAB-oprN, in the genome of CV017 and otherC. subtsugaespecies, that is not present in other members of theChromobacteriumgenus. We demonstrate that CdeAB-OprM and CseAB-OprN are both transcriptionally induced in CV017 cells treated with sub-lethal antibiotic concentrations and they are important for induction of tolerance to different antibiotics. While CdeAB-OprM has a broad antibiotic specificity, the CseAB-OprN system is highly specific for a ribosome-targeting antibiotic produced by the saprophytic bacteriumBurkholderia thailandensis,bactobolin. Finally, we use a previously developedB. thailandensis-C. subtsugaeCV017 co-culture model to demonstrate that adding sub-lethal bactobolin at the beginning of co-culture growth increases the ability of CV017 to compete withB. thailandensisin a manner that is dependent on the CseAB-OprN system. Our results provide new information on the antibiotic resistance mechanisms ofChromobacteriumspecies and highlight the importance of efflux pumps during competition with other bacterial species.IMPORTANCEThis study describes two closely related efflux pumps in members of theChromobacteriumgenus, which includes opportunistic but often-fatal pathogens and species with highly versatile metabolic capabilities. Efflux pumps remove antibiotics from the cell and are important for antibiotic resistance. One of these pumps is broadly distributed in theChromobacteriumgenus and increases resistance to clinically relevant antibiotics. The other efflux pump is present only inChromobacterium subtsugaeand is highly specific for bactobolin, an antibiotic produced by the soil saprophyteBurkholderia thailandensis. We demonstrate these pumps can be activated to increase resistance by their antibiotic substrates, and that this activation is important forC. subtsugaeto survive in a laboratory competition experiment withB. thailandensis.These results have implications for managing antibiotic-resistantChromobacteriuminfections, bioengineering ofChromobacteriumspecies, and for understanding the evolution of efflux pumps.

Download Full-text

Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance

Veterinary World ◽

10.14202/vetworld.2021.2410-2418 ◽

2021 ◽

pp. 2410-2418

Author(s):

Waleed Younis ◽

Sabry Hassan ◽

Hams M. A. Mohamed

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

16S Rrna ◽

Virulence Factors ◽

Pathogenic Bacteria ◽

Human Life ◽

Raw Milk ◽

Biochemical Tests ◽

E Coli ◽

Milk Samples

Background and Aim: Raw milk is considered an essential source of nutrition during all stages of human life because it offers a valuable supply of protein and minerals. Importantly, milk is considered a good media for the growth and contamination of many pathogenic bacteria, especially food-borne pathogens such as Escherichia coli. Thus, the objective of this study was to characterize E. coli and detect its virulence factors and antibiotic resistance from raw milk samples. Materials and Methods: Raw milk samples (n=100) were collected from different localities in Qena, Egypt, and investigated for the presence of E. coli using different biochemical tests, IMViC tests, serotyping to detect somatic antigen type, and molecularly by polymerase chain reaction (PCR) tests. The presence of different virulence and antimicrobial genes (hly, eae, stx1, stx2, blaTEM, tetA(A), and tetB genes) in E. coli isolates was evaluated using PCR. Results: The results demonstrated that 10 out of 100 milk samples were contaminated with E. coli. Depending on serology, the isolates were classified as O114 (one isolate), O27 (two isolates), O111 (one isolate), O125 (two isolates), and untypeable (five isolates) E. coli. The sequencing of partially amplified 16S rRNA of the untypeable isolates resulted in one isolate, which was initially misidentified as untypeable E. coli but later proved as Enterobacter hormaechei. Moreover, antibacterial susceptibility analysis revealed that nearly all isolates were resistant to more than 3 families of antibiotics, particularly to β-lactams, clindamycin, and rifampin. PCR results demonstrated that all E. coli isolates showed an accurate amplicon for the blaTEM and tetA(A) genes, four isolates harbored eae gene, other four harbored tetB gene, and only one isolate exhibited a positive stx2 gene. Conclusion: Our study explored vital methods for identifying E. coli as a harmful pathogen of raw milk using 16S rRNA sequencing, phylogenetic analysis, and detection of virulence factors and antibiotic-resistant genes.

Download Full-text