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Dang Z, Yang B, Xia P, Huang J, Liao J, Li Y, Tang S, Han Q, Luo S, Xia Y. Antimicrobial susceptibilities, resistance mechanisms and molecular characteristics of toxigenic Clostridioides difficile isolates in a large teaching hospital in Chongqing, China. J Glob Antimicrob Resist 2024; 38:198-204. [PMID: 39048055 DOI: 10.1016/j.jgar.2024.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 07/05/2024] [Accepted: 07/12/2024] [Indexed: 07/27/2024] Open
Abstract
OBJECTIVES Clostridioides difficile ranks among the primary sources of healthcare-related infections and diarrhoea in numerous nations. We evaluated the drug susceptibility and resistance mechanisms of C. difficile isolates from a hospital in Chongqing, China, and identified resistance rates and resistance mechanisms that differed from previous findings. METHODS The toxin genes and drug resistance genes of clinical strains were detected using Polymerase Chain Reaction (PCR), and these strains were subjected to Multilocus Sequence Typing (MLST). The agar dilution technique was employed for assessing susceptibility of antibiotics. Clinical data collection was completed through a review of electronic medical records. RESULTS A total of 67 strains of toxin-producing C. difficile were detected. All C. difficile isolates demonstrated susceptibility to both metronidazole and vancomycin. However, resistance was observed in 8.95%, 16.42%, 56.72%, 56.72%, 31.34% and 5.97% of the isolates for tigecycline, tetracycline, clindamycin, erythromycin, moxifloxacin and rifampin, respectively. Among the strains with toxin genotypes A + B + CDT - and belonging to the ST3, six strains exhibited reduced susceptibility to tigecycline (MIC=0.5mg/L) and tetracycline (MIC=8mg/L). The tetA(P) and tetB(P) genes were present in these six strains, but were absent in tetracycline-resistant strains. Resistance genes (ermB, tetM, tetA(P) and tetB(P)) and mutations (in gyrA, gyrB, and rpoB) were identified in resistant strains. CONCLUSIONS In contrast to prior studies, we found higher proportions of ST3 isolates with decreased tigecycline sensitivity, sharing similar resistance patterns and resistance genes. In the resistance process of tigecycline and tetracycline, the tetA(P) and tetB(P) genes may play a weak role.
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Affiliation(s)
- Zijun Dang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Bingxue Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Peiwen Xia
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jinzhu Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jiajia Liao
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yuqiong Li
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shiyu Tang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qi Han
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shengli Luo
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yun Xia
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Zhai J, Wang Y, Tang B, Zheng S, He S, Zhao W, Lin J, Li F, Bao Y, Lancuo Z, Liu C, Wang W. A comparison of antibiotic resistance genes and mobile genetic elements in wild and captive Himalayan vultures. PeerJ 2024; 12:e17710. [PMID: 39006014 PMCID: PMC11243982 DOI: 10.7717/peerj.17710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 06/18/2024] [Indexed: 07/16/2024] Open
Abstract
As the most widely distributed scavenger birds on the Qinghai-Tibetan Plateau, Himalayan vultures (Gyps himalayensis) feed on the carcasses of various wild and domestic animals, facing the dual selection pressure of pathogens and antibiotics and are suitable biological sentinel species for monitoring antibiotic resistance genes (ARGs). This study used metagenomic sequencing to comparatively investigate the ARGs and mobile genetic elements (MGEs) of wild and captive Himalayan vultures. Overall, the resistome of Himalayan vultures contained 414 ARG subtypes resistant to 20 ARG types, with abundances ranging from 0.01 to 1,493.60 ppm. The most abundant resistance type was beta-lactam (175 subtypes), followed by multidrug resistance genes with 68 subtypes. Decreases in the abundance of macrolide-lincosamide-streptogramin (MLS) resistance genes were observed in the wild group compared with the zoo group. A total of 75 genera (five phyla) of bacteria were predicted to be the hosts of ARGs in Himalayan vultures, and the clinical (102 ARGs) and high-risk ARGs (35 Rank I and 56 Rank II ARGs) were also analyzed. Among these ARGs, twenty-two clinical ARGs, nine Rank I ARG subtypes, sixteen Rank II ARG subtypes were found to differ significantly between the two groups. Five types of MGEs (128 subtypes) were found in Himalayan vultures. Plasmids (62 subtypes) and transposases (44 subtypes) were found to be the main MGE types. Efflux pump and antibiotic deactivation were the main resistance mechanisms of ARGs in Himalayan vultures. Decreases in the abundance of cellular protection were identified in wild Himalayan vultures compared with the captive Himalayan vultures. Procrustes analysis and the co-occurrence networks analysis revealed different patterns of correlations among gut microbes, ARGs, and MGEs in wild and captive Himalayan vultures. This study is the first step in describing the characterization of the ARGs in the gut of Himalayan vultures and highlights the need to pay more attention to scavenging birds.
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Affiliation(s)
- Jundie Zhai
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
- College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - You Wang
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
- College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - Boyu Tang
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
- College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - Sisi Zheng
- Animal Disease Prevention and Control Center of Qinghai Province, Xining, China
| | - Shunfu He
- Xining Wildlife Park of Qinghai Province, Xining, China
| | - Wenxin Zhao
- Xining Wildlife Park of Qinghai Province, Xining, China
| | - Jun Lin
- College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - Feng Li
- College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - Yuzi Bao
- College of Eco-Environmental Engineering, Qinghai University, Xining, China
| | - Zhuoma Lancuo
- College of Finance and Economics, Qinghai University, Xining, China
| | - Chuanfa Liu
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Wen Wang
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
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3
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Blau K, Berger FK, Mellmann A, Gallert C. Clostridioides difficile from Fecally Contaminated Environmental Sources: Resistance and Genetic Relatedness from a Molecular Epidemiological Perspective. Microorganisms 2023; 11:2497. [PMID: 37894155 PMCID: PMC10608975 DOI: 10.3390/microorganisms11102497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/28/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Clostridioides difficile is the most important pathogen causing antimicrobial-associated diarrhea and has recently been recognized as a cause of community-associated C. difficile infection (CA-CDI). This study aimed to characterize virulence factors, antimicrobial resistance (AMR), ribotype (RT) distribution and genetic relationship of C. difficile isolates from diverse fecally contaminated environmental sources. C. difficile isolates were recovered from different environmental samples in Northern Germany. Antimicrobial susceptibility testing was determined by E-test or disk diffusion method. Toxin genes (tcdA and tcdB), genes coding for binary toxins (cdtAB) and ribotyping were determined by PCR. Furthermore, 166 isolates were subjected to whole genome sequencing (WGS) for core genome multi-locus sequence typing (cgMLST) and extraction of AMR and virulence-encoding genes. Eighty-nine percent (148/166) of isolates were toxigenic, and 51% (76/148) were positive for cdtAB. Eighteen isolates (11%) were non-toxigenic. Thirty distinct RTs were identified. The most common RTs were RT127, RT126, RT001, RT078, and RT014. MLST identified 32 different sequence types (ST). The dominant STs were ST11, followed by ST2, ST3, and ST109. All isolates were susceptible to vancomycin and metronidazole and displayed a variable rate of resistance to moxifloxacin (14%), clarithromycin (26%) and rifampicin (2%). AMR genes, such as gyrA/B, blaCDD-1/2, aph(3')-llla-sat-4-ant(6)-la cassette, ermB, tet(M), tet(40), and tetA/B(P), conferring resistance toward fluoroquinolone, beta-lactam, aminoglycoside, macrolide and tetracycline antimicrobials, were found in 166, 137, 29, 32, 21, 72, 17, and 9 isolates, respectively. Eleven "hypervirulent" RT078 strains were detected, and several isolates belonged to RTs (i.e., RT127, RT126, RT023, RT017, RT001, RT014, RT020, and RT106) associated with CA-CDI, indicating possible transmission between humans and environmental sources pointing out to a zoonotic potential.
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Affiliation(s)
- Khald Blau
- Department of Microbiology–Biotechnology, Faculty of Technology, University of Applied Sciences Emden/Leer, 26723 Emden, Germany;
| | - Fabian K. Berger
- Institute of Medical Microbiology and Hygiene, Saarland University Medical Center, 66421 Homburg, Germany;
- German National Reference Center for Clostridioides Difficile, 66421 Homburg, Germany;
| | - Alexander Mellmann
- German National Reference Center for Clostridioides Difficile, 66421 Homburg, Germany;
- Institute of Hygiene, University of Münster, 48149 Münster, Germany
| | - Claudia Gallert
- Department of Microbiology–Biotechnology, Faculty of Technology, University of Applied Sciences Emden/Leer, 26723 Emden, Germany;
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AlJindan R, AlEraky DM, Farhat M, Almandil NB, AbdulAzeez S, Borgio JF. Genomic Insights into Virulence Factors and Multi-Drug Resistance in Clostridium perfringens IRMC2505A. Toxins (Basel) 2023; 15:359. [PMID: 37368661 DOI: 10.3390/toxins15060359] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Clostridium perfringens is a spore-forming, Gram-positive anaerobic pathogen that causes several disorders in humans and animals. A multidrug-resistant Clostridium strain was isolated from the fecal sample of a patient who was clinically suspected of gastrointestinal infection and had a recent history of antibiotic exposure and diarrhea. The strain was identified by 16s rRNA sequencing as Clostridium perfringens. The strain's pathogenesis was analyzed through its complete genome, specifically antimicrobial resistance-related genes. The Clostridium perfringens IRMC2505A genome contains 19 (Alr, Ddl, dxr, EF-G, EF-Tu, folA, Dfr, folP, gyrA, gyrB, Iso-tRNA, kasA, MurA, rho, rpoB, rpoC, S10p, and S12p) antibiotic-susceptible genetic species according to the k-mer-based detection of antimicrobial resistance genes. Genome mapping using CARD and VFDB databases revealed significant (p-value = 1 × 10-26) genes with aligned reads against antibiotic-resistant genes or virulence factors, including phospholipase C, perfringolysin O, collagenase, hyaluronidase, alpha-clostripain, exo-alpha-sialidase, and sialidase activity. In conclusion, this is the first report on C. perfringens from Saudi Arabia that conducted whole genome sequencing of IRMC2505A and confirmed the strain as an MDR bacterium with several virulence factors. Developing control strategies requires a detailed understanding of the epidemiology of C. perfringens, its virulence factors, and regional antimicrobial resistance patterns.
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Affiliation(s)
- Reem AlJindan
- Department of Microbiology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Doaa M AlEraky
- Department of Biomedical Dental Science, Microbiology and Immunology Division, Collage of Dentistry, Dammam 31441, Saudi Arabia
| | - Maha Farhat
- Department of Biochemistry, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Noor B Almandil
- Department of Clinical Pharmacy Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Sayed AbdulAzeez
- Department of Genetic Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Jesu Francis Borgio
- Department of Genetic Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
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Rostain W, Zaplana T, Boutard M, Baum C, Tabuteau S, Sanitha M, Ramya M, Guss A, Ettwiller L, Tolonen AC. Tuning of Gene Expression in Clostridium phytofermentans Using Synthetic Promoters and CRISPRi. ACS Synth Biol 2022; 11:4077-4088. [PMID: 36427328 PMCID: PMC9765743 DOI: 10.1021/acssynbio.2c00385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Indexed: 11/27/2022]
Abstract
Control of gene expression is fundamental to cell engineering. Here we demonstrate a set of approaches to tune gene expression in Clostridia using the model Clostridium phytofermentans. Initially, we develop a simple benchtop electroporation method that we use to identify a set of replicating plasmids and resistance markers that can be cotransformed into C. phytofermentans. We define a series of promoters spanning a >100-fold expression range by testing a promoter library driving the expression of a luminescent reporter. By insertion of tet operator sites upstream of the reporter, its expression can be quantitatively altered using the Tet repressor and anhydrotetracycline (aTc). We integrate these methods into an aTc-regulated dCas12a system with which we show in vivo CRISPRi-mediated repression of reporter and fermentation genes in C. phytofermentans. Together, these approaches advance genetic transformation and experimental control of gene expression in Clostridia.
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Affiliation(s)
- William Rostain
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Tom Zaplana
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Magali Boutard
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Chloé Baum
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
- New
England Biolabs, Inc., 240 County Road, Ipswich, Massachusetts 01938, United States
| | - Sibylle Tabuteau
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Mary Sanitha
- Molecular
Genetics Laboratory, Department of Genetic Engineering, College of
Engineering and Technology, SRM Institute
of Science and Technology, SRM Nagar, Kattankulathur-603 203, TN, India
| | - Mohandass Ramya
- Molecular
Genetics Laboratory, Department of Genetic Engineering, College of
Engineering and Technology, SRM Institute
of Science and Technology, SRM Nagar, Kattankulathur-603 203, TN, India
| | - Adam Guss
- Biosciences
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6038, United States
| | - Laurence Ettwiller
- New
England Biolabs, Inc., 240 County Road, Ipswich, Massachusetts 01938, United States
| | - Andrew C. Tolonen
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
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Infection with a human-derived enteroinvasive Escherichia coli strain altered intestinal barrier function in guinea pigs. Int Microbiol 2022; 25:723-732. [PMID: 35725861 DOI: 10.1007/s10123-022-00255-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND/AIMS The aim was to characterize a bacterium causing intestinal mucosal barrier damage and to identify the possible invasion mechanism. MATERIALS AND METHODS The intestinal permeability and tight junction protein levels were detected in guinea pigs infected with Escherichia coli D-09 via immunofluorescence analysis and western blotting. In order to explain this invasion mechanism at the gene level, whole genome sequencing analysis was performed on this bacterium. RESULTS The results showed an increased intestinal permeability and upregulated expression of the leaky protein claudin-2 in both the colon and liver of the infected animals. In addition, the draft genome of E. coli D-09 comprised 42 scaffolds (size, > 645 bp) with a total size of 4,679,567 bp. A total of 4379 protein coding genes were identified, which contained 45 antibiotic resistance and 86 virulence-related genes and covered 88.0% of the whole genome. CONCLUSIONS This study verified that the human-derived enteroinvasive E. coli strain could destroy intestinal barrier function in guinea pigs. Additionally, our data first characterized the genome features of E. coli O124:K72 D-09, which may provide new insights into the possible invasion mechanism.
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The host-specific resistome in environmental feces of Eurasian otters (Lutra lutra) and leopard cats (Prionailurus bengalensis) revealed by metagenomic sequencing. One Health 2022; 14:100385. [PMID: 35399616 PMCID: PMC8987634 DOI: 10.1016/j.onehlt.2022.100385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/29/2022] [Accepted: 03/29/2022] [Indexed: 11/26/2022] Open
Abstract
Investigation of feces of wildlife, which is considered as reservoirs, melting pots, vectors and secondary sources of antimicrobial resistance genes (ARGs), provides insights into the risks and ecology of ARGs in the environment. Here, we investigated microbiomes, virulence factor genes (VFGs) of bacterial pathogens, and resistomes in environmental feces of Eurasian otters (Lutra lutra) and leopard cats (Prionailurus bengalensis) using shotgun metagenome sequencing. As expected, the taxonomic compositions of bacteria were significantly different between the animals. Importantly, we found that the compositions of ARGs were also significantly different between the animals. We detected ARGs including iri, tetA(P), tetB(P), floR, sulII, strA, strB, tetW and tetY. Some of them were significantly more abundant in either of the host animals, such as strA, strB and tetY in Eurasian otters, and tetA(P), tetW and iri in leopard cats. We also found that some ARGs were selectively correlated to particular VFGs-related bacteria, such as tetA(P) and tetB(P) to Clostridium, and iri to Mycobacterium. We also found that there were positive correlations between Acinetobacter and ARGs of multiple antimicrobial classes. The host-specific resistomes and VFGs-related bacteria may be due to differences in the host's gut microbiome, diet and/or habitat, but further investigation is needed. Overall, this study provided important baseline information about the resistomes of the wildlife in Korea, which may help the conservation of these endangered species and assessment of human health risks posed by ARGs and bacterial pathogens from wildlife. Fecal ARGs and VFGs were investigated in wild Eurasian otters and leopard cats. The ARGs and VFGs were widespread in both the host animals. Certain ARGs and VFGs were differentially more abundant in either of the hosts. Multiple ARGs showed positive correlations with Acinetobacter VFGs. Consistent monitoring of ARGs in wildlife is needed from a One Health perspective.
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Das A, Dhar PK, Dutta A, Jalal MS, Ghosh P, Das T, Barua H, Biswas PK. Circulation of oxytetracycline- and ciprofloxacin-resistant commensal Escherichia coli strains in broiler chickens and farm environments, Bangladesh. Vet World 2020; 13:2395-2400. [PMID: 33363332 PMCID: PMC7750236 DOI: 10.14202/vetworld.2020.2395-2400] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/24/2020] [Indexed: 01/08/2023] Open
Abstract
Background and Aim: The emergence of antimicrobial resistance (AMR) in commensal organism, such as Escherichia coli of food animals, is an alarming issue for global health. It increases the possibility of transmitting AMR determinant(s) to human bacterial pathogens by transferable genetic materials, particularly by plasmids. Hence, it is important to know which resistant genes are being carried by commensal organisms in food chain in a country and their level of temporal loads. As a result, pre-emptive measures can be advocated with an aim to reduce their risks in their primary source of circulation which consequently would benefit the public health. Materials and Methods: Commensal E. coli strains from broiler chickens on randomly selected 30 farms and the farm environments were examined for the frequencies of isolation of resistant strains to oxytetracycline and ciprofloxacin. Five birds were randomly selected from each farm to collect cloacal swab samples (total of 150 samples). Furthermore, a total of 150 environmental samples comprising one each from feed, water, soil, litter, and litter damping site of each farm were screened for the isolation of commensal E. coli strains. Strains thus obtained were initially tested for their resistance to oxytetracycline and ciprofloxacin by Kirby–Bauer disk diffusion method. Oxytetracycline-resistant strains were further screened for the presence of resistance determining genes, namely, tetA, tetB, and tetC by uniplex polymerase chain reactions. Risks associated with the isolation frequency of oxytetracycline- and ciprofloxacin-resistant E. coli were also assessed by univariable logistic regression analysis. Results: The results revealed that all E. coli isolates, regardless of the source of origin, were resistant to oxytetracycline, while 78.4% (95% confidence interval [CI] 69.1-85.5%) showed resistance to ciprofloxacin. All the randomly selected (20) oxytetracycline-resistant strains harbored the tetA gene, whereas tetB and tetC were reported in three and two isolates, respectively. After univariable analysis, only one variable, that is, strain 1 of broiler chickens compared to two other strains was found to be positively associated with the isolation of ciprofloxacin-resistant E. coli (odds ratio 12.75 [95% CI 1.0-157.1], p=0.047). Conclusion: Resistance emerged against oxytetracycline and ciprofloxacin in commensal E. coli strains circulating in live poultry and farm environments in Bangladesh seems to be very high. Thus, human infection with drug-resistant E. coli strains through food chain will critically compromise the therapeutic measures currently available.
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Affiliation(s)
- Avijit Das
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Pangkaj Kumar Dhar
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Avijit Dutta
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Mohammad Shah Jalal
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Priya Ghosh
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Tridip Das
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Himel Barua
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
| | - Paritosh Kumar Biswas
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram, Bangladesh
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Fourie JCJ, Bezuidenhout CC, Sanko TJ, Mienie C, Adeleke R. Inside environmental Clostridium perfringens genomes: antibiotic resistance genes, virulence factors and genomic features. JOURNAL OF WATER AND HEALTH 2020; 18:477-493. [PMID: 32833675 DOI: 10.2166/wh.2020.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Until recently, research has focused on Clostridium perfringens in clinical settings without considering environmental isolates. In this study, environmental genomes were used to investigate possible antibiotic resistance and the presence of virulence traits in C. perfringens strains from raw surface water. In silico assembly of three C. perfringens strains, DNA generated almost complete genomes setting their length ranging from 3.4 to 3.6 Mbp with GC content of 28.18%. An average of 3,175 open reading frames was identified, with the majority associated with carbohydrate and protein metabolisms. The genomes harboured several antibiotic resistance genes for glycopeptides, macrolide-lincosamide-streptogramin B, β-lactam, trimethoprim, tetracycline and aminoglycosides and also the presence of several genes encoding for polypeptides and multidrug resistance efflux pumps and 35 virulence genes. Some of these encode for haemolysins, sialidase, hyaluronidase, collagenase, perfringolysin O and phospholipase C. All three genomes contained sequences indicating phage, antibiotic resistance and pathogenic islands integration sites. A genomic comparison of these three strains confirmed high similarity and shared core genes with clinical C. perfringens strains, highlighting their health security risks. This study provides a genomic insight into the potential pathogenicity of C. perfringens present in the environment and emphasises the importance of monitoring this niche in the future.
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Affiliation(s)
| | | | - Tomasz Janusz Sanko
- Unit for Environmental Science and Management, North-West University, Potchefstroom, South Africa E-mail:
| | - Charlotte Mienie
- Unit for Environmental Science and Management, North-West University, Potchefstroom, South Africa E-mail:
| | - Rasheed Adeleke
- Unit for Environmental Science and Management, North-West University, Potchefstroom, South Africa E-mail:
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Archambault M, Rubin JE. Antimicrobial Resistance in Clostridium and Brachyspira spp. and Other Anaerobes. Microbiol Spectr 2020; 8:10.1128/microbiolspec.arba-0020-2017. [PMID: 31971162 PMCID: PMC10773235 DOI: 10.1128/microbiolspec.arba-0020-2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Indexed: 01/26/2023] Open
Abstract
This article describes the antimicrobial resistance to date of the most frequently encountered anaerobic bacterial pathogens of animals. The different sections show that antimicrobial resistance can vary depending on the antimicrobial, the anaerobe, and the resistance mechanism. The variability in antimicrobial resistance patterns is also associated with other factors such as geographic region and local antimicrobial usage. On occasion, the same resistance gene was observed in many anaerobes, whereas some were limited to certain anaerobes. This article focuses on antimicrobial resistance data of veterinary origin.
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Affiliation(s)
- Marie Archambault
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec J2S 2M2, Canada
| | - Joseph E Rubin
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatchewan S7N 5B4, Canada
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Hu T, Wang X, Zhen L, Gu J, Zhang K, Wang Q, Ma J, Peng H. Effects of inoculation with lignocellulose-degrading microorganisms on antibiotic resistance genes and the bacterial community during co-composting of swine manure with spent mushroom substrate. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:110-118. [PMID: 31146224 DOI: 10.1016/j.envpol.2019.05.078] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/11/2019] [Accepted: 05/15/2019] [Indexed: 06/09/2023]
Abstract
Composting is usually employed to treat livestock manure, and inoculation with lignocellulose-degrading microorganisms can enhance the quality of compost. In this study, lignocellulose-degrading microorganisms were inoculated at two levels (uninoculated control = 0%, and T treatment = 10%) during co-composting of swine manure with spent mushroom substrate, and their effects on antibiotic resistance genes (ARGs) and the bacterial community were investigated. Inoculation with lignocellulose-degrading microorganisms caused greater decreases in 6/11 ARGs and 3/4 mobile genetic elements than the control. The total relative abundances of ARGs increased by 0.23 logs in the control but decreased by 0.08 logs in the T treatment after co-composting. The bacterial community was clustered according to the composting time in the two treatments, where inoculation mainly affected the bacterial community during the mesophilic phase. Redundancy analysis and network analysis showed that the bacterial community succession had important effects on the variations in ARGs. Inoculation with lignocellulose-degrading microorganisms led to the reduction of ARGs, which was significantly correlated with the abundances of potential host bacteria for ARGs. Thus, inoculation with lignocellulose-degrading microorganisms could decrease the risk of ARGs spreading and make compost products more security.
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Affiliation(s)
- Ting Hu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China; Shaanxi Province Institute of Microbiology, Xi'an, Shaanxi, 710043, China
| | - Xiaojuan Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Lisha Zhen
- Shaanxi Province Institute of Microbiology, Xi'an, Shaanxi, 710043, China
| | - Jie Gu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| | - Kaiyu Zhang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qianzhi Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jiyue Ma
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Huiling Peng
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China
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Blau K, Jacquiod S, Sørensen SJ, Su JQ, Zhu YG, Smalla K, Jechalke S. Manure and Doxycycline Affect the Bacterial Community and Its Resistome in Lettuce Rhizosphere and Bulk Soil. Front Microbiol 2019; 10:725. [PMID: 31057496 PMCID: PMC6477490 DOI: 10.3389/fmicb.2019.00725] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/22/2019] [Indexed: 12/23/2022] Open
Abstract
Manure application to agricultural soil introduces antibiotic residues and increases the abundance of antibiotic-resistant bacteria (ARB) carrying antibiotic resistance genes (ARGs), often located on mobile genetic elements (MGEs). The rhizosphere is regarded as a hotspot of microbial activity and gene transfer, which can alter and prolong the effects of organic fertilizers containing antibiotics. However, not much is known about the influence of plants on the effects of doxycycline applied to soil via manure. In this study, the effects of manure spiked with or without doxycycline on the prokaryotic community composition as well as on the relative abundance of ARGs and MGEs in lettuce rhizosphere and bulk soil were investigated by means of a polyphasic cultivation-independent approach. Samples were taken 42 days after manure application, and total community DNA was extracted. Besides a pronounced manure effect, doxycycline spiking caused an additional enrichment of ARGs and MGEs. High-throughput quantitative PCR revealed an increase in tetracycline, aminoglycoside, and macrolide-lincosamide-streptogramin B (MLSB) resistance genes associated with the application of manure spiked with doxycycline. This effect was unexpectedly lower in the rhizosphere than in bulk soil, suggesting a faster dissipation of the antibiotic and a more resilient prokaryotic community in the rhizosphere. Interestingly, the tetracycline resistance gene tetA(P) was highly enriched in manure-treated bulk soil and rhizosphere, with highest values observed in doxycycline-treated bulk soil, concurring with an enrichment of Clostridia. Thus, the gene tetA(P) might be a suitable marker of soil contamination by ARB, ARGs, and antibiotics of manure origin. These findings illustrate that the effects of manure and doxycycline on ARGs and MGEs differ between rhizosphere and bulk soil, which needs to be considered when assessing risks for human health connected to the spread of ARGs in the environment.
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Affiliation(s)
- Khald Blau
- Julius Kühn-Institut—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - Samuel Jacquiod
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Søren J. Sørensen
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jian-Qiang Su
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Kornelia Smalla
- Julius Kühn-Institut—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - Sven Jechalke
- Julius Kühn-Institut—Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
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Vidor CJ, Bulach D, Awad M, Lyras D. Paeniclostridium sordellii and Clostridioides difficile encode similar and clinically relevant tetracycline resistance loci in diverse genomic locations. BMC Microbiol 2019; 19:53. [PMID: 30832583 PMCID: PMC6399922 DOI: 10.1186/s12866-019-1427-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 02/25/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND With the current rise of antibiotic resistance in bacteria, it is important to monitor the efficacy of antimicrobials in clinical use. Paeniclostridium sordellii (previously Clostridium sordellii) is a bacterial pathogen that causes human uterine infection after spontaneous or medically induced abortion, for which mortality rates approach 100%. Prophylactic antibiotics have been recommended for individuals undergoing medically-induced abortion, one of which is doxycycline, a member of the tetracycline antibiotic family. However, tetracycline resistance had not been well characterized in P. sordellii. This study therefore aimed to determine the levels of tetracycline resistance in P. sordellii isolates, and to identify associated loci and their genomic locations. RESULTS Using a MIC assay, five of 24 P. sordellii isolates were found to be resistant to tetracycline, minocycline, and importantly, doxycycline. Analysis of genome sequence data from 46 isolates found that phenotypically resistant isolates encoded a variant of the Clostridium perfringens tetracycline resistance determinant Tet P. Bioinformatic analysis and comparison of the regions surrounding these determinants found variation in the genomic location of Tet P among P. sordellii isolates. The core genome comparison of the 46 isolates revealed genetic diversity and the absence of dominant genetic types among the isolates. There was no strong association between geographic location of isolation, animal host or Tet P carriage with isolate genetic type. Furthermore, the analysis of the Tet P genotype revealed that Tet P is encoded chromosomally, or on one of two, novel, small plasmids, all consistent with multiple acquisition and recombination events. BLAST analysis of Clostridioides difficile draft genome sequences also identified a Tet P locus, the genomic location of which demonstrated an evolutionary relationship with the P. sordellii locus. CONCLUSIONS The Tet P determinant is found in variable genomic locations within diverse human and animal isolates of P. sordellii and C. difficile, which suggests that it can undergo horizontal transfer, and may disseminate tetracycline resistance between clostridial species. Doxycycline is a suggested prophylactic treatment for P. sordellii infections, however, a small sub-set of the isolates tested are resistant to this antibiotic. Doxycycline may therefore not be an appropriate prophylactic treatment for P. sordellii infections.
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Affiliation(s)
- Callum J Vidor
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Dieter Bulach
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Milena Awad
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Dena Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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Adams V, Han X, Lyras D, Rood JI. Antibiotic resistance plasmids and mobile genetic elements of Clostridium perfringens. Plasmid 2018; 99:32-39. [DOI: 10.1016/j.plasmid.2018.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/25/2018] [Accepted: 07/25/2018] [Indexed: 10/28/2022]
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15
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Zhou Y, Niu L, Zhu S, Lu H, Liu W. Occurrence, abundance, and distribution of sulfonamide and tetracycline resistance genes in agricultural soils across China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:1977-1983. [PMID: 28558428 DOI: 10.1016/j.scitotenv.2017.05.152] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 05/26/2023]
Abstract
The prevalence and proliferation of antibiotic resistance genes (ARGs) have been identified as an emerging contaminant of concern and a crucial threat to public health worldwide. In this study, we carried out a nation-wide sampling campaign across China to investigate the distribution and abundances of 8 major ARGs in agricultural soils. The levels of sulfonamide (sul) and tetracycline (tet) resistance genes in China's agricultural soils ranged from 10-6-10-2 to 10-8-10-2 gene copies/16S rRNA gene copies, respectively. Northeast China is the hot-spot of ARGs, likely due to long-term wastewater irrigation in the area. Redundancy analysis was further performed to assess the influences of environmental variables on ARG abundances. Sulfonamide resistance genes displayed strong correlations with meteorological parameters (mean annual precipitation and temperature), and decreased from north to south. In comparison, tetracycline resistance genes were more closely related to soil organic matter and pH. Co-selection between heavy metals and ARGs was significant among Cu, Hg and sulfonamide resistance genes. This study highlighted the current status of ARG contamination and their influencing factors in China's agricultural soils. Findings are valuable to identify effective management options for reducing the release of antibiotics and control ARG spread in the agriculture sector across the world.
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Affiliation(s)
- Yuting Zhou
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Lili Niu
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Siyu Zhu
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Huijie Lu
- Institute of Eco-environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Department of Civil and Environment Engineering, University of Vermont Burlington, VT 05405, United States.
| | - Weiping Liu
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
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16
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Kang Y, Gu X, Hao Y, Hu J. Autoclave treatment of pig manure does not reduce the risk of transmission and transfer of tetracycline resistance genes in soil: successive determinations with soil column experiments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:4551-4560. [PMID: 26517996 DOI: 10.1007/s11356-015-5671-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 10/21/2015] [Indexed: 06/05/2023]
Abstract
The increasing use of antibiotics, especially tetracycline, in livestock feed adversely affects animal health and ecological integrity. Therefore, approaches to decrease this risk are urgently needed. High temperatures facilitate antibiotic degradation; whether this reduces transmission risk and transfer of tetracycline-resistant bacteria (TRBs) and tetracycline resistance genes (TRGs) in soil remains unknown. Successive experiments with soil columns evaluated the effects of autoclaving pig manure (APM) on soil TRB populations and TRGs over time at different soil depths. The data showed sharp increases in TRB populations and TRGs in each subsoil layer of PM (non-APM) and APM treatments within 30 days, indicating that TRBs and TRGs transferred rapidly. The level of TRBs in the upper soil layers was approximately 15-fold higher than in subsoils. TRBs were not dependent on PM and APM levels, especially in the late phase. Nevertheless, higher levels of APM led to rapid expansion of TRBs as compared to PM. Moreover, temporal changes in TRB frequencies in total culturable bacteria (TCBs) were similar to TRBs, indicating that the impact of PM or APM on TRBs was more obvious than for TCBs. TRBs were hypothesized to depend on the numbers of TRGs and indigenous recipient bacteria. In the plough layer, five TRGs (tetB, tetG, tetM, tetW, and tetB/P) existed in each treatment within 150 days. Selective pressure of TC may not be a necessary condition for the transfer and persistence of TRGs in soil. High temperatures might reduce TRBs in PM, which had minimal impact on the transmission and transfer of TRGs in soil. Identifying alternatives to decrease TRG transmission remains a major challenge.
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Affiliation(s)
- Yijun Kang
- College of Marine and Bio-engineering, Yancheng Teachers University, Yancheng, Jiangsu, Peoples Republic of China
| | - Xian Gu
- Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu, Peoples Republic of China
| | - Yangyang Hao
- Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu, Peoples Republic of China
| | - Jian Hu
- Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu, Peoples Republic of China.
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17
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Roberts MC, Schwarz S. Tetracycline and Phenicol Resistance Genes and Mechanisms: Importance for Agriculture, the Environment, and Humans. JOURNAL OF ENVIRONMENTAL QUALITY 2016; 45:576-592. [PMID: 27065405 DOI: 10.2134/jeq2015.04.0207] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recent reports have speculated on the future impact that antibiotic-resistant bacteria will have on food production, human health, and global economics. This review examines microbial resistance to tetracyclines and phenicols, antibiotics that are widely used in global food production. The mechanisms of resistance, mode of spread between agriculturally and human-impacted environments and ecosystems, distribution among bacteria, and the genes most likely to be associated with agricultural and environmental settings are included. Forty-six different tetracycline resistance () genes have been identified in 126 genera, with (M) having the broadest taxonomic distribution among all bacteria and (B) having the broadest coverage among the Gram-negative genera. Phenicol resistance genes are organized into 37 groups and have been identified in 70 bacterial genera. The review provides the latest information on tetracycline and phenicol resistance genes, including their association with mobile genetic elements in bacteria of environmental, medical, and veterinary relevance. Knowing what specific antibiotic-resistance genes (ARGs) are found in specific bacterial species and/or genera is critical when using a selective suite of ARGs for detection or surveillance studies. As detection methods move to molecular techniques, our knowledge about which type of bacteria carry which resistance gene(s) will become more important to ensure that the whole spectrum of bacteria are included in future surveillance studies. This review provides information needed to integrate the biology, taxonomy, and ecology of tetracycline- and phenicol-resistant bacteria and their resistance genes so that informative surveillance strategies can be developed and the correct genes selected.
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18
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Huang M, Qi F, Wang J, Xu Q, Lin L. Changes of bacterial diversity and tetracycline resistance in sludge from AAO systems upon exposure to tetracycline pressure. JOURNAL OF HAZARDOUS MATERIALS 2015; 298:303-309. [PMID: 26079369 DOI: 10.1016/j.jhazmat.2015.05.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/08/2015] [Accepted: 05/23/2015] [Indexed: 06/04/2023]
Abstract
Two lab-scale anaerobic-anoxic-oxic (AAO) systems were used to investigate the changes in tetracycline (TC) resistance and bacterial diversity upon exposure to TC pressure. High-throughput sequencing was used to detect diversity changes in microorganisms at the level of class in sludge from different bioreactors with and without TC. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the abundances of eight tetracycline resistance genes (TRGs), tetA, tetB, tetC, tetE, tetM, tetO, tetS and tetX. The results showed that the diversities of the microbial communities of anoxic, anaerobic and aerobic sludge all increased with the addition of TC. TC substantially changed the structure of the microbial community regardless of oxygen conditions. Bacteroidetes and Proteobacteria were the dominant species in the three kinds of sludge and were substantially enriched with TC pressure. In sludge with TC added, almost all target TRGs proliferated more than those in sludge without TC except tetX, which decreased in anaerobic sludge with TC addition. The concentration of efflux pump genes, tet(A-C, E), was the highest among the three groups of TRGs in the different kinds of sludge.
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Affiliation(s)
- Manhong Huang
- College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
| | - Fangfang Qi
- College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China
| | - Jue Wang
- College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China
| | - Qi Xu
- College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China
| | - Li Lin
- College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China
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Vidor C, Awad M, Lyras D. Antibiotic resistance, virulence factors and genetics of Clostridium sordellii. Res Microbiol 2014; 166:368-74. [PMID: 25290059 DOI: 10.1016/j.resmic.2014.09.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/25/2014] [Accepted: 09/09/2014] [Indexed: 02/04/2023]
Abstract
Clostridium sordellii is gram positive bacterial pathogen of humans and animals. While the incidence of human-related C. sordellii infection is low, the mortality rate associated with infection is high. Of particular concern are C. sordellii infections after child-birth or medical abortion, which have an almost 100% mortality rate. Recent genetic and epidemiological work has increased our understanding of how this pathogen has evolved and how it causes disease. This review will summarise studies involving the genetics of C. sordellii, including an antibiotic resistance profile, the genetic determinants of virulence and mutagenesis of C. sordellii.
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Affiliation(s)
- Callum Vidor
- Department of Microbiology, Monash University, Victoria 3800, Australia.
| | - Milena Awad
- Department of Microbiology, Monash University, Victoria 3800, Australia.
| | - Dena Lyras
- Department of Microbiology, Monash University, Victoria 3800, Australia.
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21
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Beceiro A, Tomás M, Bou G. Antimicrobial resistance and virulence: a successful or deleterious association in the bacterial world? Clin Microbiol Rev 2013; 26:185-230. [PMID: 23554414 PMCID: PMC3623377 DOI: 10.1128/cmr.00059-12] [Citation(s) in RCA: 616] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hosts and bacteria have coevolved over millions of years, during which pathogenic bacteria have modified their virulence mechanisms to adapt to host defense systems. Although the spread of pathogens has been hindered by the discovery and widespread use of antimicrobial agents, antimicrobial resistance has increased globally. The emergence of resistant bacteria has accelerated in recent years, mainly as a result of increased selective pressure. However, although antimicrobial resistance and bacterial virulence have developed on different timescales, they share some common characteristics. This review considers how bacterial virulence and fitness are affected by antibiotic resistance and also how the relationship between virulence and resistance is affected by different genetic mechanisms (e.g., coselection and compensatory mutations) and by the most prevalent global responses. The interplay between these factors and the associated biological costs depend on four main factors: the bacterial species involved, virulence and resistance mechanisms, the ecological niche, and the host. The development of new strategies involving new antimicrobials or nonantimicrobial compounds and of novel diagnostic methods that focus on high-risk clones and rapid tests to detect virulence markers may help to resolve the increasing problem of the association between virulence and resistance, which is becoming more beneficial for pathogenic bacteria.
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22
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Ji X, Shen Q, Liu F, Ma J, Xu G, Wang Y, Wu M. Antibiotic resistance gene abundances associated with antibiotics and heavy metals in animal manures and agricultural soils adjacent to feedlots in Shanghai; China. JOURNAL OF HAZARDOUS MATERIALS 2012; 235-236:178-85. [PMID: 22868748 DOI: 10.1016/j.jhazmat.2012.07.040] [Citation(s) in RCA: 533] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 07/16/2012] [Accepted: 07/18/2012] [Indexed: 05/23/2023]
Abstract
Eight antibiotic resistance genes (ARGs), 7 heavy metals, and 6 antibiotics were quantified in manures and soils collected from multiple feedlots in Shanghai. The samples were analyzed to determine if ARG abundances were associated with heavy metal concentration and independent of antibiotics. The results revealed the presence of chloramphenicol, sulfonamides and tetracyclines at concentration ranges of 3.27-17.85, 5.85-33.37 and 4.54-24.66 mg kg(-1), respectively. Typical heavy metals, such as Cu, Zn, and As, were detected at concentration ranges of 32.3-730.1, 75.9-4333.8, and 2.6-617.2 mg kg(-1). All ARGs tested were detected in the collected samples except tetB(P), which was absent in animal manures. Overall, sulfonamide ARGs were more abundant than tetracycline ARGs. Except for sulII, only a weak positive correlation was found between ARGs and their corresponding antibiotics. On the contrary, significant positive correlations (p<0.05) were found between some ARGs and typical heavy metals. For example, sulA and sulIII were strongly correlated with levels of Cu, Zn and Hg. The data demonstrated that the presence of ARGs was relatively independent of their respective antibiotic inducer. In addition to antibiotics, toxic heavy metals, such as Hg, Cu, and Zn, exerted a strong selection pressure and acted as complementary factors for ARG abundance.
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Affiliation(s)
- Xiuling Ji
- School of Environmental Science and Engineering, Donghua University, Shanghai, 201620, PR China. ling
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23
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Charlebois A, Jalbert LA, Harel J, Masson L, Archambault M. Characterization of genes encoding for acquired bacitracin resistance in Clostridium perfringens. PLoS One 2012; 7:e44449. [PMID: 22970221 PMCID: PMC3435297 DOI: 10.1371/journal.pone.0044449] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 08/06/2012] [Indexed: 11/19/2022] Open
Abstract
Phenotypic bacitracin resistance has been reported in Clostridium perfringens. However, the genes responsible for the resistance have not yet been characterized. Ninety-nine C. perfringens isolates recovered from broilers and turkeys were tested for phenotypic bacitracin resistance. Bacitracin MIC(90) (>256 µg/ml) was identical for both turkey and chicken isolates; whereas MIC(50) was higher in turkey isolates (6 µg/ml) than in chicken isolates (3 µg/ml). Twenty-four of the 99 isolates showed high-level bacitracin resistance (MIC breakpoint >256 µg/ml) and the genes encoding for this resistance were characterized in C. perfringens c1261_A strain using primer walking. Sequence analysis and percentages of amino acid identity revealed putative genes encoding for both an ABC transporter and an overproduced undecaprenol kinase in C. perfringens c1261_A strain. These two mechanisms were shown to be both encoded by the putative bcrABD operon under the control of a regulatory gene, bcrR. Efflux pump inhibitor thioridazine was shown to increase significantly the susceptibility of strain c1261_A to bacitracin. Upstream and downstream from the bcr cluster was an IS1216-like element, which may play a role in the dissemination of this resistance determinant. Pulsed-field gel electrophoresis with prior double digestion with I-CeuI/MluI enzymes followed by hybridization analyses revealed that the bacitracin resistance genes bcrABDR were located on the chromosome. Semi-quantitative RT-PCR demonstrated that this gene cluster is expressed under bacitracin stress. Microarray analysis revealed the presence of these genes in all bacitracin resistant strains. This study reports the discovery of genes encoding for a putative ABC transporter and an overproduced undecaprenol kinase associated with high-level bacitracin resistance in C. perfringens isolates from turkeys and broiler chickens.
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Affiliation(s)
- Audrey Charlebois
- Department of pathology and microbiology, Faculty of Veterinary Medicine of the University of Montreal, Centre de Recherche en Infectiologie Porcine (CRIP), Saint-Hyacinthe, Québec, Canada
| | - Louis-Alexandre Jalbert
- Department of pathology and microbiology, Faculty of Veterinary Medicine of the University of Montreal, Centre de Recherche en Infectiologie Porcine (CRIP), Saint-Hyacinthe, Québec, Canada
| | - Josée Harel
- Department of pathology and microbiology, Faculty of Veterinary Medicine of the University of Montreal, Centre de Recherche en Infectiologie Porcine (CRIP), Saint-Hyacinthe, Québec, Canada
| | - Luke Masson
- Biotechnology Research Institute, Montréal, Québec, Canada
| | - Marie Archambault
- Department of pathology and microbiology, Faculty of Veterinary Medicine of the University of Montreal, Centre de Recherche en Infectiologie Porcine (CRIP), Saint-Hyacinthe, Québec, Canada
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Necrotic enteritis-derived Clostridium perfringens strain with three closely related independently conjugative toxin and antibiotic resistance plasmids. mBio 2011; 2:mBio.00190-11. [PMID: 21954306 PMCID: PMC3181468 DOI: 10.1128/mbio.00190-11] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The pathogenesis of avian necrotic enteritis involves NetB, a pore-forming toxin produced by virulent avian isolates of Clostridium perfringens type A. To determine the location and mobility of the netB structural gene, we examined a derivative of the tetracycline-resistant necrotic enteritis strain EHE-NE18, in which netB was insertionally inactivated by the chloramphenicol and thiamphenicol resistance gene catP. Both tetracycline and thiamphenicol resistance could be transferred either together or separately to a recipient strain in plate matings. The separate transconjugants could act as donors in subsequent matings, which demonstrated that the tetracycline resistance determinant and the netB gene were present on different conjugative elements. Large plasmids were isolated from the transconjugants and analyzed by high-throughput sequencing. Analysis of the resultant data indicated that there were actually three large conjugative plasmids present in the original strain, each with its own toxin or antibiotic resistance locus. Each plasmid contained a highly conserved 40-kb region that included plasmid replication and transfer regions that were closely related to the 47-kb conjugative tetracycline resistance plasmid pCW3 from C. perfringens. The plasmids were as follows: (i) a conjugative 49-kb tetracycline resistance plasmid that was very similar to pCW3, (ii) a conjugative 82-kb plasmid that contained the netB gene and other potential virulence genes, and (iii) a 70-kb plasmid that carried the cpb2 gene, which encodes a different pore-forming toxin, beta2 toxin. The anaerobic bacterium Clostridium perfringens can cause an avian gastrointestinal disease known as necrotic enteritis. Disease pathogenesis is not well understood, although the plasmid-encoded pore-forming toxin NetB, is an important virulence factor. In this work, we have shown that the plasmid that carries the netB gene is conjugative and has a 40-kb region that is very similar to replication and transfer regions found within each of the sequenced conjugative plasmids from C. perfringens. We also showed that this strain contained two additional large plasmids that were also conjugative and carried a similar 40-kb region. One of these plasmids encoded beta2 toxin, and the other encoded tetracycline resistance. To our knowledge, this is the first report of a bacterial strain that carries three closely related but different independently conjugative plasmids. These results have significant implications for our understanding of the transmission of virulence and antibiotic resistance genes in pathogenic bacteria.
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Park M, Rooney AP, Hecht DW, Li J, McClane BA, Nayak R, Paine DD, Rafii F. Phenotypic and genotypic characterization of tetracycline and minocycline resistance in Clostridium perfringens. Arch Microbiol 2010; 192:803-10. [DOI: 10.1007/s00203-010-0605-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/02/2010] [Accepted: 07/05/2010] [Indexed: 10/19/2022]
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Heap JT, Pennington OJ, Cartman ST, Minton NP. A modular system for Clostridium shuttle plasmids. J Microbiol Methods 2009; 78:79-85. [PMID: 19445976 DOI: 10.1016/j.mimet.2009.05.004] [Citation(s) in RCA: 344] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 05/07/2009] [Accepted: 05/08/2009] [Indexed: 10/20/2022]
Abstract
Despite their medical and industrial importance, our basic understanding of the biology of the genus Clostridium is rudimentary in comparison to their aerobic counterparts in the genus Bacillus. A major contributing factor has been the comparative lack of sophistication in the gene tools available to the clostridial molecular biologist, which are immature, and in clear need of development. The transfer and maintenance of recombinant, replicative plasmids into various species of Clostridium has been reported, and several elements suitable as shuttle plasmid components are known. However, these components have to-date only been available in disparate plasmid contexts, and their use has not been broadly explored. Here we describe the specification, design and construction of a standardized modular system for Clostridium-Escherichia coli shuttle plasmids. Existing replicons and selectable markers were incorporated, along with a novel clostridial replicon. The properties of these components were compared, and the data allow researchers to identify combinations of components potentially suitable for particular hosts and applications. The system has been extensively tested in our laboratory, where it is utilized in all ongoing recombinant work. We propose that adoption of this modular system as a standard would be of substantial benefit to the Clostridium research community, whom we invite to use and contribute to the system.
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Affiliation(s)
- John T Heap
- BBSRC Sustainable BioEnergy Centre, School of Molecular Medical Sciences, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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A new tetracycline efflux gene, tet(40), is located in tandem with tet(O/32/O) in a human gut firmicute bacterium and in metagenomic library clones. Antimicrob Agents Chemother 2008; 52:4001-9. [PMID: 18779355 DOI: 10.1128/aac.00308-08] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterium Clostridium saccharolyticum K10, isolated from a fecal sample obtained from a healthy donor who had received long-term tetracycline therapy, was found to carry three tetracycline resistance genes: tet(W) and the mosaic tet(O/32/O), both conferring ribosome protection-type resistance, and a novel, closely linked efflux-type resistance gene designated tet(40). tet(40) encodes a predicted membrane-associated protein with 42% amino acid identity to tetA(P). Tetracycline did not accumulate in Escherichia coli cells expressing the Tet(40) efflux protein, and resistance to tetracycline was reduced when cells were incubated with an efflux pump inhibitor. E. coli cells carrying tet(40) had a 50% inhibitory concentration of tetracycline of 60 microg/ml. Analysis of a transconjugant from a mating between donor strain C. saccharolyticum K10 and the recipient human gut commensal bacterium Roseburia inulinivorans suggested that tet(O/32/O) and tet(40) were cotransferred on a mobile element. Sequence analysis of a 37-kb insert identified on the basis of tetracycline resistance from a metagenomic fosmid library again revealed a tandem arrangement of tet(O/32/O) and tet(40), flanked by regions with homology to parts of the VanG operon previously identified in Enterococcus faecalis. At least 10 of the metagenomic inserts that carried tet(O/32/O) also carried tet(40), suggesting that tet(40), although previously undetected, may be an abundant efflux gene.
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Parsons JA, Bannam TL, Devenish RJ, Rood JI. TcpA, an FtsK/SpoIIIE homolog, is essential for transfer of the conjugative plasmid pCW3 in Clostridium perfringens. J Bacteriol 2007; 189:7782-90. [PMID: 17720795 PMCID: PMC2168741 DOI: 10.1128/jb.00783-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conjugative tetracycline resistance plasmid pCW3 is the paradigm conjugative plasmid in the anaerobic gram-positive pathogen Clostridium perfringens. Two closely related FtsK/SpoIIIE homologs, TcpA and TcpB, are encoded on pCW3, which is significant since FtsK domains are found in coupling proteins of gram-negative conjugation systems. To develop an understanding of the mechanism of conjugative transfer in C. perfringens, we determined the role of these proteins in the conjugation process. Mutation and complementation analysis was used to show that the tcpA gene was essential for the conjugative transfer of pCW3 and that the tcpB gene was not required for transfer. Furthermore, complementation of a pCW3DeltatcpA mutant with divergent tcpA homologs provided experimental evidence that all of the known conjugative plasmids from C. perfringens use a similar transfer mechanism. Functional genetic analysis of the TcpA protein established the essential role in conjugative transfer of its Walker A and Walker B ATP-binding motifs and its FtsK-like RAAG motif. It is postulated that TcpA is the essential DNA translocase or coupling protein encoded by pCW3 and as such represents a key component of the unique conjugation process in C. perfringens.
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Affiliation(s)
- Jennifer A Parsons
- Department of Microbiology, Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton Campus, Victoria 3800, Australia
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Abstract
Treatment of infections is compromised worldwide by the emergence of bacteria that are resistant to multiple antibiotics. Although classically attributed to chromosomal mutations, resistance is most commonly associated with extrachromosomal elements acquired from other bacteria in the environment. These include different types of mobile DNA segments, such as plasmids, transposons, and integrons. However, intrinsic mechanisms not commonly specified by mobile elements-such as efflux pumps that expel multiple kinds of antibiotics-are now recognized as major contributors to multidrug resistance in bacteria. Once established, multidrug-resistant organisms persist and spread worldwide, causing clinical failures in the treatment of infections and public health crises.
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Bannam TL, Teng WL, Bulach D, Lyras D, Rood JI. Functional identification of conjugation and replication regions of the tetracycline resistance plasmid pCW3 from Clostridium perfringens. J Bacteriol 2006; 188:4942-51. [PMID: 16788202 PMCID: PMC1483020 DOI: 10.1128/jb.00298-06] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens causes fatal human infections, such as gas gangrene, as well as gastrointestinal diseases in both humans and animals. Detailed molecular analysis of the tetracycline resistance plasmid pCW3 from C. perfringens has shown that it represents the prototype of a unique family of conjugative antibiotic resistance and virulence plasmids. We have identified the pCW3 replication region by deletion and transposon mutagenesis and showed that the essential rep gene encoded a basic protein with no similarity to any known plasmid replication proteins. An 11-gene conjugation locus containing 5 genes that encoded putative proteins with similarity to proteins from the conjugative transposon Tn916 was identified, although the genes' genetic arrangements were different. Functional genetic studies demonstrated that two of the genes in this transfer clostridial plasmid (tcp) locus, tcpF and tcpH, were essential for the conjugative transfer of pCW3, and comparative analysis confirmed that the tcp locus was not confined to pCW3. The conjugation region was present on all known conjugative plasmids from C. perfringens, including an enterotoxin plasmid and other toxin plasmids. These results have significant implications for plasmid evolution, as they provide evidence that a nonreplicating Tn916-like element can evolve to become the conjugation locus of replicating plasmids that carry major virulence genes or antibiotic resistance determinants.
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Affiliation(s)
- Trudi L Bannam
- Australian Research Council Centre of Excellence in Structural and Functional Microbial genomics and Victorian Bioinformatics Consortium, Department of Microbiology, Monash University, Victoria 3800, Australia.
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Hecht DW. Anaerobes: Antibiotic resistance, clinical significance, and the role of susceptibility testing. Anaerobe 2006; 12:115-21. [PMID: 16765857 DOI: 10.1016/j.anaerobe.2005.10.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 10/27/2005] [Indexed: 11/29/2022]
Affiliation(s)
- David W Hecht
- Hines VA Hospital, Loyola University Medical Center, 2160 S. First Avenue, Maywood, IL 60153, USA.
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Kather EJ, Marks SL, Foley JE. Determination of the prevalence of antimicrobial resistance genes in canine Clostridium perfringens isolates. Vet Microbiol 2006; 113:97-101. [PMID: 16330169 DOI: 10.1016/j.vetmic.2005.10.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 10/06/2005] [Accepted: 10/07/2005] [Indexed: 11/16/2022]
Abstract
Clostridium perfringens is a well documented cause of a mild self-limiting diarrhea and a potentially fatal acute hemorrhagic diarrheal syndrome in the dog. A recent study documented that 21% of canine C. perfringens isolates had MIC's indicative of resistance to tetracycline, an antimicrobial commonly recommended for treatment of C. perfringens-associated diarrhea. The objective of the present study was to further evaluate the antimicrobial susceptibility profiles of these isolates by determining the prevalence of specific resistance genes, their expression, and ability for transference between bacteria. One hundred and twenty-four canine C. perfringens isolates from 124 dogs were evaluated. Minimum inhibitory concentrations of tetracycline, erythromycin, tylosin, and metronidazole were determined using the CLSI Reference Agar Dilution Method. All isolates were screened for three tetracycline resistance genes: tetA(P), tetB(P) and tetM, and two macrolide resistance genes: ermB and ermQ, via PCR using primer sequences previously described. Ninety-six percent (119/124) of the isolates were positive for the tetA(P) gene, and 41% (51/124) were positive for both the tetA(P) and tetB(P) genes. No isolates were positive for the tetB(P) gene alone. Highly susceptible isolates (MIC< or = 4 microg/ml) were significantly more likely to lack the tetB(P) gene. One isolate (0.8%) was positive for the ermB gene, and one isolate was positive for the ermQ gene. The tetM gene was not found in any of the isolates tested. Two out of 15 tested isolates (13%) demonstrated transfer of tetracycline resistance via bacterial conjugation. Tetracycline should be avoided for the treatment of C. perfringens-associated diarrhea in dogs because of the relatively high prevalence of in vitro resistance, and the potential for conjugative transfer of antimicrobial resistance.
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Affiliation(s)
- Elizabeth J Kather
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis 2108 Tupper Hall, Davis, CA 95616, USA
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Hamon MA, Stanley NR, Britton RA, Grossman AD, Lazazzera BA. Identification of AbrB-regulated genes involved in biofilm formation by Bacillus subtilis. Mol Microbiol 2004; 52:847-60. [PMID: 15101989 PMCID: PMC1409746 DOI: 10.1111/j.1365-2958.2004.04023.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacillus subtilis is a ubiquitous soil bacterium that forms biofilms in a process that is negatively controlled by the transcription factor AbrB. To identify the AbrB-regulated genes required for biofilm formation by B. subtilis, genome-wide expression profiling studies of biofilms formed by spo0A abrB and sigH abrB mutant strains were performed. These data, in concert with previously published DNA microarray analysis of spo0A and sigH mutant strains, led to the identification of 39 operons that appear to be repressed by AbrB. Eight of these operons had previously been shown to be repressed by AbrB, and we confirmed AbrB repression for a further six operons by reverse transcription-PCR. The AbrB-repressed genes identified in this study are involved in processes known to be regulated by AbrB, such as extracellular degradative enzyme production and amino acid metabolism, and processes not previously known to be regulated by AbrB, such as membrane bioenergetics and cell wall functions. To determine whether any of these AbrB-regulated genes had a role in biofilm formation, we tested 23 mutants, each with a disruption in a different AbrB-regulated operon, for the ability to form biofilms. Two mutants had a greater than twofold defect in biofilm formation. A yoaW mutant exhibited a biofilm structure with reduced depth, and a sipW mutant exhibited only surface-attached cells and did not form a mature biofilm. YoaW is a putative secreted protein, and SipW is a signal peptidase. This is the first evidence that secreted proteins have a role in biofilm formation by Bacillus subtilis.
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Affiliation(s)
- Mélanie A. Hamon
- Department of Microbiology, Immunology and Molecular Genetics University of California Los Angeles 1602 Molecular Sciences Building 405 Hilgard Avenue Los Angeles, CA 90095, USA
| | - Nicola R. Stanley
- Department of Microbiology, Immunology and Molecular Genetics University of California Los Angeles 1602 Molecular Sciences Building 405 Hilgard Avenue Los Angeles, CA 90095, USA
| | - Robert A. Britton
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139, USA
| | - Alan. D. Grossman
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139, USA
| | - Beth A. Lazazzera
- Department of Microbiology, Immunology and Molecular Genetics University of California Los Angeles 1602 Molecular Sciences Building 405 Hilgard Avenue Los Angeles, CA 90095, USA
- *For correspondence. E-mail; Tel (+1) 310 794 4804; Fax (+1) 310 206 5231
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Johansson A, Greko C, Engström BE, Karlsson M. Antimicrobial susceptibility of Swedish, Norwegian and Danish isolates of Clostridium perfringens from poultry, and distribution of tetracycline resistance genes. Vet Microbiol 2004; 99:251-7. [PMID: 15066727 DOI: 10.1016/j.vetmic.2004.01.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Revised: 12/05/2003] [Accepted: 12/17/2003] [Indexed: 11/28/2022]
Abstract
This study was undertaken to determine the in vitro susceptibility of Clostridium perfringens, isolated from poultry to antimicrobials used in poultry production. The minimal inhibitory concentration (MIC) of eight antimicrobials, including the ionophoric coccidiostat narasin, was determined for 102 C. perfringens isolates, 58 from Sweden, 24 from Norway and 20 from Denmark. Susceptibility to each antimicrobial compound was determined by broth microdilution. The isolates were obtained from broilers (89), laying hens (9) and turkeys (4), affected by necrotic enteritis (NE) or by C. perfringens associated hepatitis (CPH), and from healthy broilers. All strains, regardless of origin, proved inherently susceptible to ampicillin, narasin, avilamycin, erythromycin and vancomycin. A low frequency of resistance to virginiamycin and bacitracin was also found. Resistance to tetracycline was found in strains isolated in all three countries; Sweden (76%), Denmark (10%) and Norway (29%). In 80% of the tetracycline-resistant isolates, the two resistance genes tetA(P) and tetB(P) were amplified by PCR whereas in 20% only the tetA(P) gene was detected. No tetM gene amplicon was obtained from any of the tetracycline-resistant isolates. The uniform susceptibility to narasin revealed in this study shows that the substance can still be used to control clostridiosis. In this study, C. perfringens also showed a low degree of resistance to most other antimicrobials tested. Despite the small amounts of tetracycline used in poultry, a considerable degree of resistance to tetracycline was found in C. perfringens isolates from Swedish broilers.
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Affiliation(s)
- A Johansson
- Department of Bacteriology, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
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Yamamoto K, Sasaki Y, Ogikubo Y, Noguchi N, Sasatsu M, Takahashi T. Identification of the tetracycline resistance gene, tet(M), in Erysipelothrix rhusiopathiae. ACTA ACUST UNITED AC 2004; 48:293-301. [PMID: 15129584 DOI: 10.1046/j.1439-0450.2001.00442.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This is the first report to demonstrate the presence of tet(M) in naturally occurring isolates of tetracycline-resistant Erysipelothrix rbusiopathiae, which causes swine erysipelas. The tet(M) gene was isolated from E. rhusiopathiae strain KY5-42. The nucleotide and the deduced amino acid sequence were 99% identical to the tet(M) gene from Enterococcus faecalis. The gene was necessary and sufficient for the expression of tetracycline resistance in Escherichia coli. The presence of the tet(M) gene in the 114 tetracycline-resistant E. rhusiopathiae isolates from diseased pigs was detected by the polymerase chain reaction assay. The specific amplified DNA fragment was obtained from all 114 tetracycline-resistant strains. It was suggested that the tet(M) gene was widely present in the field isolates of E. rhusiopathiae resistant to tetracycline.
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Affiliation(s)
- K Yamamoto
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1, Tokura, Kokubunji, Tokyo, 185-8511, Japan
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Martel A, Devriese LA, Cauwerts K, De Gussem K, Decostere A, Haesebrouck F. Susceptibility ofClostridium perfringensstrains from broiler chickens to antibiotics and anticoccidials. Avian Pathol 2004; 33:3-7. [PMID: 14681061 DOI: 10.1080/0307945031000163291] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Clostridium perfringens strains isolated in 2002 from the intestines of broiler chickens from 31 different farms located in Belgium were tested for susceptibility to 12 antibiotics used for therapy, growth promotion or prevention of coccidiosis. All strains were uniformly sensitive to the ionophore antibiotics monensin, lasalocid, salinomycin, maduramycin and narasin. All were sensitive to avilamycin, tylosin and amoxicillin, while flavomycin (bambermycin) showed low or no activity. Chlortetracycline and oxytetracycline were active at very low concentrations, but low-level acquired resistance was detected in 66% of the strains investigated. Fifty percent of these strains carried the tetP(B) resistance gene, while the tet(Q) gene was detected in only one strain. One strain with high-level resistance against tetracyclines carried the tet(M) gene. Sixty-three percent of the strains showed low-level resistance to lincomycin. The lnu(A) and lnu(B) genes were each only found in one strain. Compared with a similar investigation carried out in 1980, an increase was seen in resistance percentages with lincomycin (63% against 49%) and a slight decrease with tetracycline (66% against 74%).
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Affiliation(s)
- A Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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Bannam TL, Johanesen PA, Salvado CL, Pidot SJA, Farrow KA, Rood JI. The Clostridium perfringens TetA(P) efflux protein contains a functional variant of the Motif A region found in major facilitator superfamily transport proteins. Microbiology (Reading) 2004; 150:127-134. [PMID: 14702405 DOI: 10.1099/mic.0.26614-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Clostridium perfringens tetracycline resistance protein, TetA(P), is an inner-membrane protein that mediates the active efflux of tetracycline from the bacterial cell. This protein comprises 420 aa and is predicted to have 12 transmembrane domains (TMDs). Comparison of the TetA(P) amino acid sequence to that of several members of the major facilitator superfamily (MFS) identified a variant copy of the conserved Motif A. This region consists of the sequence E59xPxxxxxDxxxRK72 and is located within the putative loop joining TMDs 2 and 3 in the predicted structural model of the TetA(P) protein. To study the functional importance of the conserved residues, site-directed mutagenesis was used to construct 17 point mutations that were then analysed for their effect on tetracycline resistance and their ability to produce an immunoreactive TetA(P) protein. Changes to the conserved Phe-58 residue were tolerated, whereas three independent substitutions of Pro-61 abolished tetracycline resistance. Examination of the basic residues showed that Arg-71 is required for function, whereas tetracycline resistance was retained when Lys-72 was substituted with arginine. These results confirm that the region encoding this motif is important for tetracycline resistance and represents a distant version of the Motif A region found in other efflux proteins and members of the MFS family. In addition, it was shown that Glu-117 of the TetA(P) protein, which is predicted to be located in TMD4, is important for resistance although a derivative with an aspartate residue at this position is also functional.
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Affiliation(s)
- Trudi L Bannam
- ARC Centre for Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Priscilla A Johanesen
- ARC Centre for Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Chelsea L Salvado
- ARC Centre for Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Sacha J A Pidot
- ARC Centre for Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Kylie A Farrow
- ARC Centre for Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Julian I Rood
- ARC Centre for Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Victoria 3800, Australia
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Trieber CA, Taylor DE. Mutations in the 16S rRNA genes of Helicobacter pylori mediate resistance to tetracycline. J Bacteriol 2002; 184:2131-40. [PMID: 11914344 PMCID: PMC134973 DOI: 10.1128/jb.184.8.2131-2140.2002] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2001] [Accepted: 01/24/2002] [Indexed: 12/11/2022] Open
Abstract
Low-cost and rescue treatments for Helicobacter pylori infections involve combinations of several drugs including tetracycline. Resistance to tetracycline has recently emerged in H. pylori. The 16S rRNA gene sequences of two tetracycline-resistant clinical isolates (MIC = 64 microg/ml) were determined and compared to the consensus H. pylori 16S rRNA sequence. One isolate had four nucleotide substitutions, and the other had four substitutions and two deletions. Natural transformation with the 16S rRNA genes from the resistant organisms conferred tetracycline resistance on susceptible strains. 16S rRNA genes containing the individual mutations were constructed and tested for the ability to confer resistance. Only the 16S rRNA gene containing the triple mutation, AGA965-967TTC, was able to confer tetracycline resistance on H. pylori 26695. The MICs of tetracycline for the transformed strains were equivalent to those for the original clinical isolates. The two original isolates were also metronidazole resistant, but this trait was not linked to the tetracycline resistance phenotype. Serial passage of several H. pylori strains on increasing concentrations of tetracycline yielded mutants with only a very modest increase in tetracycline resistance to a MIC of 4 to 8 microg/ml. These mutants all had a deletion of G942 in the 16S rRNA genes. The mutations in the 16S rRNA are clearly responsible for tetracycline resistance in H. pylori.
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Affiliation(s)
- Catharine A Trieber
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
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Roberts MC. Resistance to tetracycline, macrolide-lincosamide-streptogramin, trimethoprim, and sulfonamide drug classes. Mol Biotechnol 2002; 20:261-83. [PMID: 11936257 DOI: 10.1385/mb:20:3:261] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The discovery and use of antimicrobial agents in the last 50 yr has been one of medicine's greatest achievements. These agents have reduced morbidity and mortality of humans and animals and have directly contributed to human's increased life span. However, bacteria are becoming increasingly resistant to these agents by mutations, which alter existing bacterial proteins, and/or acquisition of new genes, which provide new proteins. The latter are often associated with mobile elements that can be exchanged quickly across bacterial populations and may carry multiple antibiotic genes for resistance. In some case, virulence factors are also found on these same mobile elements. There is mounting evidence that antimicrobial use in agriculture, both plant and animal, and for environmental purposes does influence the antimicrobial resistant development in bacteria important in humans and in reverse. In this article, we will examine the genes which confer resistance to tetracycline, macrolide-lincosamide-streptogramin (MLS), trimethoprim, and sulfonamide.
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Affiliation(s)
- Marilyn C Roberts
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle 98195, USA.
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40
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Johanesen PA, Lyras D, Bannam TL, Rood JI. Transcriptional analysis of the tet(P) operon from Clostridium perfringens. J Bacteriol 2001; 183:7110-9. [PMID: 11717269 PMCID: PMC95559 DOI: 10.1128/jb.183.24.7110-7119.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Clostridium perfringens tetracycline resistance determinant from the 47-kb conjugative R-plasmid pCW3 is unique in that it consists of two overlapping genes, tetA(P) and tetB(P), which mediate resistance by different mechanisms. Detailed transcriptional analysis has shown that the inducible tetA(P) and tetB(P) genes comprise an operon that is transcribed from a single promoter, P3, located 529 bp upstream of the tetA(P) start codon. Deletion of P3 or alteration of the spacing between the -35 and -10 regions significantly reduced the level of transcription in a reporter construct. Induction was shown to be mediated at the level of transcription. Unexpectedly, a factor-independent terminator, T1, was detected downstream of P3 but before the start of the tetA(P) gene. Deletion or mutation of this terminator led to increased read-through transcription in the reporter construct. It is postulated that the T1 terminator is an intrinsic control element of the tet(P) operon and that it acts to prevent the overexpression of the TetA(P) transmembrane protein, even in the presence of tetracycline.
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Affiliation(s)
- P A Johanesen
- Bacterial Pathogenesis Research Group, Department of Microbiology, Monash University, Victoria 3800, Australia
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41
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Johanesen PA, Lyras D, Rood JI. Induction of pCW3-encoded tetracycline resistance in Clostridium perfringens involves a host-encoded factor. Plasmid 2001; 46:229-32. [PMID: 11735372 DOI: 10.1006/plas.2001.1543] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The tetracycline resistance determinant Tet P, which is encoded by the conjugative plasmid pCW3 from Clostridium perfringens, is induced by subinhibitory concentrations of tetracycline. In this study we have shown that the inducible phenotype is strain dependent. When pCW3 is present in derivatives of the wild-type strains CW234 and CW362 resistance is inducible. However, transfer to derivatives of strain 13 leads to a constitutive phenotype that is only observed in this strain background. Based on these results it is proposed that induction of the pCW3-encoded tet(P) genes in C. perfringens requires a host-encoded factor that is either absent or nonfunctional in strain 13 derivatives.
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Affiliation(s)
- P A Johanesen
- Bacterial Pathogenesis Research Group, Monash University, Victoria 3800, Australia
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42
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Quiñones M, Knesek JE, McIntire SA. Sequence and gene expression analyses of plasmid pHPM8 from Helicobacter pylori reveal the presence of two operons with putative roles in plasmid replication and antibiotic activity. Plasmid 2001; 46:223-8. [PMID: 11735371 DOI: 10.1006/plas.2001.1541] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The DNA sequence of a 7.8-kb Helicobacter pylori plasmid, pHPM8, was determined. Six open reading frames (ORFs) were present. Ribonuclease protection studies showed that ORF1/ORF2 and ORF3/ORF4 genes are organized in operons possibly involved in plasmid replication and in production of a peptide with antibiotic activity, respectively. Finding areas of pHPM8 with a high level of identity to H. pylori chromosomal DNA supported the hypothesis that recombination occurs between plasmids and the chromosome of H. pylori.
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Affiliation(s)
- M Quiñones
- Biology Department, Texas Woman's University, Denton, Texas 76204, USA
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43
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Sasaki Y, Yamamoto K, Tamura Y, Takahashi T. Tetracycline-resistance genes of Clostridium perfringens, Clostridium septicum and Clostridium sordellii isolated from cattle affected with malignant edema. Vet Microbiol 2001; 83:61-9. [PMID: 11524166 DOI: 10.1016/s0378-1135(01)00402-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The minimal inhibitory concentrations (MICs) of 10 antimicrobial agents against a total of 33 isolates of Clostridium perfringens, Clostridium septicum and Clostridium sordellii from cattle affected with malignant edema in Japan was determined. The low MIC activities of benzylpenicillin confirm the place of benzylpenicillin as the antibiotics of choice for treatment of malignant edema. Five (22%) of 23 C. septicum strains, five (71%) of seven C. perfringens strains and all strains of C. sordellii showed resistance to oxytetracycline. These oxytetracycline-resistant strains carried tetracycline-resistance genes [tetA(P), tetA408(P), tetB(P) and tetM]. The sequences of the tetracycline-resistance genes of some C. septicum strains were completely or nearly completely identical to those of strains belonging to other clostridiual species. This is the first report of resistance of C. septicum to tetracycline.
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Affiliation(s)
- Y Sasaki
- National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1 Tokura, Kokubunji, Tokyo 185-8511, Japan.
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44
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Brumlik MJ, Szymajda U, Zakowska D, Liang X, Redkar RJ, Patra G, Del Vecchio VG. Use of long-range repetitive element polymorphism-PCR to differentiate Bacillus anthracis strains. Appl Environ Microbiol 2001; 67:3021-8. [PMID: 11425716 PMCID: PMC92975 DOI: 10.1128/aem.67.7.3021-3028.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of Bacillus anthracis is extremely monomorphic, and thus individual strains have often proven to be recalcitrant to differentiation at the molecular level. Long-range repetitive element polymorphism-PCR (LR REP-PCR) was used to differentiate various B. anthracis strains. A single PCR primer derived from a repetitive DNA element was able to amplify variable segments of a bacterial genome as large as 10 kb. We were able to characterize five genetically distinct groups by examining 105 B. anthracis strains of diverse geographical origins. All B. anthracis strains produced fingerprints comprising seven to eight bands, referred to as "skeleton" bands, while one to three "diagnostic" bands differentiated between B. anthracis strains. LR REP-PCR fingerprints of B. anthracis strains showed very little in common with those of other closely related species such as B. cereus, B. thuringiensis, and B. mycoides, suggesting relative heterogeneity among the non-B. anthracis strains. Fingerprints from transitional non-B. anthracis strains, which possessed the B. anthracis chromosomal marker Ba813, scarcely resembled those observed for any of the five distinct B. anthracis groups that we have identified. The LR REP-PCR method described in this report provides a simple means of differentiating B. anthracis strains.
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Affiliation(s)
- M J Brumlik
- Institute of Molecular Biology and Medicine, University of Scranton, Scranton, Pennsylvania 18510, USA
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45
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Chopra I, Roberts M. Tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance. Microbiol Mol Biol Rev 2001; 65:232-60 ; second page, table of contents. [PMID: 11381101 PMCID: PMC99026 DOI: 10.1128/mmbr.65.2.232-260.2001] [Citation(s) in RCA: 2458] [Impact Index Per Article: 106.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. They are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. The first tetracycline-resistant bacterium, Shigella dysenteriae, was isolated in 1953. Tetracycline resistance now occurs in an increasing number of pathogenic, opportunistic, and commensal bacteria. The presence of tetracycline-resistant pathogens limits the use of these agents in treatment of disease. Tetracycline resistance is often due to the acquisition of new genes, which code for energy-dependent efflux of tetracyclines or for a protein that protects bacterial ribosomes from the action of tetracyclines. Many of these genes are associated with mobile plasmids or transposons and can be distinguished from each other using molecular methods including DNA-DNA hybridization with oligonucleotide probes and DNA sequencing. A limited number of bacteria acquire resistance by mutations, which alter the permeability of the outer membrane porins and/or lipopolysaccharides in the outer membrane, change the regulation of innate efflux systems, or alter the 16S rRNA. New tetracycline derivatives are being examined, although their role in treatment is not clear. Changing the use of tetracyclines in human and animal health as well as in food production is needed if we are to continue to use this class of broad-spectrum antimicrobials through the present century.
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Affiliation(s)
- I Chopra
- Antimicrobial Research Centre and Division of Microbiology, School of Biochemistry & Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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Shoemaker NB, Vlamakis H, Hayes K, Salyers AA. Evidence for extensive resistance gene transfer among Bacteroides spp. and among Bacteroides and other genera in the human colon. Appl Environ Microbiol 2001; 67:561-8. [PMID: 11157217 PMCID: PMC92621 DOI: 10.1128/aem.67.2.561-568.2001] [Citation(s) in RCA: 361] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transfer of antibiotic resistance genes by conjugation is thought to play an important role in the spread of resistance. Yet virtually no information is available about the extent to which such horizontal transfers occur in natural settings. In this paper, we show that conjugal gene transfer has made a major contribution to increased antibiotic resistance in Bacteroides species, a numerically predominant group of human colonic bacteria. Over the past 3 decades, carriage of the tetracycline resistance gene, tetQ, has increased from about 30% to more than 80% of strains. Alleles of tetQ in different Bacteroides species, with one exception, were 96 to 100% identical at the DNA sequence level, as expected if horizontal gene transfer was responsible for their spread. Southern blot analyses showed further that transfer of tetQ was mediated by a conjugative transposon (CTn) of the CTnDOT type. Carriage of two erythromycin resistance genes, ermF and ermG, rose from <2 to 23% and accounted for about 70% of the total erythromycin resistances observed. Carriage of tetQ and the erm genes was the same in isolates taken from healthy people with no recent history of antibiotic use as in isolates obtained from patients with Bacteroides infections. This finding indicates that resistance transfer is occurring in the community and not just in clinical environments. The high percentage of strains that are carrying these resistance genes in people who are not taking antibiotics is consistent with the hypothesis that once acquired, these resistance genes are stably maintained in the absence of antibiotic selection. Six recently isolated strains carried ermB genes. Two were identical to erm(B)-P from Clostridium perfringens, and the other four had only one to three mismatches. The nine strains with ermG genes had DNA sequences that were more than 99% identical to the ermG of Bacillus sphaericus. Evidently, there is a genetic conduit open between gram-positive bacteria, including bacteria that only pass through the human colon, and the gram-negative Bacteroides species. Our results support the hypothesis that extensive gene transfer occurs among bacteria in the human colon, both within the genus Bacteroides and among Bacteroides species and gram-positive bacteria.
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Affiliation(s)
- N B Shoemaker
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801, USA
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47
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Infections due to anaerobic bacteria and the role of antimicrobial susceptibility testing of anaerobes. ACTA ACUST UNITED AC 2001. [DOI: 10.1097/00013542-200101000-00001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Aminov RI, Garrigues-Jeanjean N, Mackie RI. Molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins. Appl Environ Microbiol 2001; 67:22-32. [PMID: 11133424 PMCID: PMC92507 DOI: 10.1128/aem.67.1.22-32.2001] [Citation(s) in RCA: 432] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phylogenetic analysis of tetracycline resistance genes encoding the ribosomal protection proteins (RPPs) revealed the monophyletic origin of these genes. The most deeply branching class, exemplified by tet and otrA, consisted of genes from the antibiotic-producing organisms Streptomyces rimosus and Streptomyces lividans. With a high degree of confidence, the corresponding genes of the other seven classes (Tet M, Tet S, Tet O, Tet W, Tet Q, Tet T, and TetB P) formed phylogenetically distinct separate clusters. Based on this phylogenetic analysis, a set of PCR primers for detection, retrieval, and sequence analysis of the corresponding gene fragments from a variety of bacterial and environmental sources was developed and characterized. A pair of degenerate primers targeted all tetracycline resistance genes encoding RPPs except otrA and tet, and seven other primer pairs were designed to target the specific classes. The primers were used to detect the circulation of these genes in the rumina of cows, in swine feed and feces, and in swine fecal streptococci. Classes Tet O and Tet W were found in the intestinal contents of both animals, while Tet M was confined to pigs and Tet Q was confined to the rumen. The tet(O) and tet(W) genes circulating in the microbiota of the rumen and the gastrointestinal tract of pigs were identical despite the differences in animal hosts and antibiotic use regimens. Swine fecal streptococci uniformly possessed the tet(O) gene, and 22% of them also carried tet(M). This population could be considered one of the main reservoirs of these two resistance genes in the pig gastrointestinal tract. All classes of RPPs except Tet T and TetB P were found in the commercial components of swine feed. This is the first demonstration of the applicability of molecular ecology techniques to estimation of the gene pool and the flux of antibiotic resistance genes in production animals.
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Affiliation(s)
- R I Aminov
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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Widdowson CA, Klugman KP. The molecular mechanisms of tetracycline resistance in the pneumococcus. Microb Drug Resist 2000; 4:79-84. [PMID: 9533730 DOI: 10.1089/mdr.1998.4.79] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Tetracycline resistance in the pneumococcus is a result of the acquisition of one of two resistance determinants, tet(M) or tet(O). These genes encode ribosomal protection proteins that have homology to the elongation factors G and Tu. Tet(M) and Tet(O) both have GTPase activity that appears to be important in the displacement of tetracycline from the ribosome. Modification of tRNA may also be important for tetracycline resistance. Transcription of tet(M) is thought to be regulated by transcriptional attenuation. Transcription of tet(O) is constitutive, however, upstream of the gene are sequences that also appear to be involved in transcriptional attenuation. tet(M) is transferred on the conjugative transposons, Tn1545 and Tn5151. It is not yet known whether tet(O) is transported on transposons or plasmids, or whether it is chromosomally integrated, in pneumococci.
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Affiliation(s)
- C A Widdowson
- South African Institute for Medical Research and the University of Witwatersrand, Department of Clinical Microbiology and Infectious Diseases, Johannesburg
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50
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Bannam TL, Rood JI. Identification of structural and functional domains of the tetracycline efflux protein TetA(P) from Clostridium perfringens. MICROBIOLOGY (READING, ENGLAND) 1999; 145 ( Pt 10):2947-55. [PMID: 10537217 DOI: 10.1099/00221287-145-10-2947] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Clostridium perfringens tetracycline-resistance protein, TetA(P), is an integral inner-membrane protein that mediates the active efflux of tetracycline from the cell. TetA(P) acts as an antiporter, presumably transporting a divalent cation-tetracycline complex in exchange for a proton, and is predicted to have 12 transmembrane domains (TMDs). Two glutamate residues that are located in predicted TMD 2 were previously shown to be required for the active efflux of tetracycline by TetA(P). To identify additional residues that are required for the structure or function of TetA(P), a random mutagenesis approach was used. Of the 61 tetracycline-susceptible mutants that were obtained in Escherichia coli, 31 different derivatives were shown to contain a single amino acid change that resulted in reduced tetracycline resistance. The stability of the mutant TetA(P) proteins was examined by immunoblotting and 19 of these strains were found to produce a detectable TetA(P) protein. The MIC of these derivatives ranged from 2 to 15 microg tetracycline ml(-1), compared to 30 microg tetracycline ml(-1) for the wild-type. The majority of these mutants clustered into three potential loop regions of the TetA(P) protein, namely the cytoplasmic loops 2-3 and 4-5, and loop 7-8, which is predicted to be located in the periplasm in E. coli. It is concluded that these regions are of functional significance in the TetA(P)-mediated efflux of tetracycline from the bacterial cell.
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Affiliation(s)
- T L Bannam
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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