scholarly journals Molecular and Functional Characterization of a Novel Plasmid-Borne blaNDM variant, blaAFM-1, in a Clinical Strain of Aeromonas Hydrophila

Author(s):  
Xi Lin ◽  
Junwan Lu ◽  
Changrui Qian ◽  
Hailong Lin ◽  
Qiaoling Li ◽  
...  

Abstract BackgroundAeromonas hydrophila is a zoonotic and human opportunistic pathogen. Increasing antibiotic resistance profiles have been discovered in both clinical and environmental A. hydrophila isolates in recent years. However, there are still very few in-depth studies regarding the role of plasmids in antibiotic resistance of A. hydrophila. Hence, we investigate the molecular characterization and functional characterization of a multidrug resistant plasmid which encoding a novel NDM variant, AFM-1, in clinical A. hydrophila SS332.MethodsThe minimum inhibitory concentrations (MICs) of 24 antibiotics for A. hydrophila SS332 were measured by the agar dilution method. The genome of A. hydrophila SS332 was sequenced with Pacific and Illumina platforms. Six plasmid-borne antimicrobial resistance genes were chosen for cloning, including blaAFM-1, blaOXA-1, msr(E), mph(E), aac(6')-Ib10, and aph(3')-Ia. Phylogenetic analysis, amino acid sequence alignment, and comparative genomic analysis were performed to elucidate the active site requirements and genetic context of blaAFM-1 gene.ResultsA. hydrophila SS332 showed high levels of resistance to 15 antibiotics, especially those with MIC levels up to or higher than 1024 μg/mL, including ampicillin, cefazolin, ceftriaxone, aztreonam, spectinomycin, roxithromycin. Six plasmid-borne resistance genes were verified to be functional in E. coli DH5α. The blaAFM-1 gene, a novel blaNDM variant, encodes a subclass B1 metallo-β-lactamase AFM-1 which shares 86% amino acid identity with NDM-1. AFM-1 showed resistance to penicillins, cephalosporins and carbapenems. Besides, blaAFM-1 gene was associated with three different novel ISCR19-like elements, designated ISCR19-1, ISCR19-2 and ∆ISCR19-3, which may be involved in the acquisition and mobilization of blaAFM-1 gene. ConclusionsOur investigation showed that plasmid-borne resistance genes played a major role in the resistance profiles of A. hydrophila SS332. A novel blaNDM variant, blaAFM-1, was verified to be functional and disseminated among different bacteria species mediated by novel ISCR19-like elements. The fact indicated that the risk of spread of novel resistance genes and novel ISCR elements.

2021 ◽  
Vol Volume 14 ◽  
pp. 1613-1622
Author(s):  
Xi Lin ◽  
Junwan Lu ◽  
Changrui Qian ◽  
Hailong Lin ◽  
Qiaoling Li ◽  
...  

Author(s):  
Tasha Santiago-Rodriguez

Antibiotic-resistance has long been associated with the use and abuse of antibiotics. However, increasing evidence is suggesting that antibiotic-resistance is in fact a phenomenon that has been occurring in natural environments for thousands and possibly millions of years. With the expansion of the microbiome field, it is now possible to characterize antibiotic-resistance genes altogether in different samples, including the human gut. This has also enabled the characterization of ancient human gut microbiomes, which also include antibiotic-resistance genes. Mummified gut remains represent a unique opportunity to characterize the microbiome and antibiotic-resistance genes prior the antibiotic-therapy era. Surprisingly, mummies from the Inca and Italian nobility cultures showed to possess antibiotic-resistance-like genes similar to modern-day antibiotic-resistance genes conferring resistance to beta-lactams, sulfa, quinolones and vancomycin, just to mention a few examples. This is intriguing as it further supports that antibiotic-resistance began in the environment and was transferred to the human gut by means that remain to be investigated and are a matter of ongoing speculation.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4613 ◽  
Author(s):  
Yongda Zhao ◽  
Lili Guo ◽  
Jie Li ◽  
Xianhui Huang ◽  
Binghu Fang

BackgroundHaemophilus parasuisis a common porcine respiratory pathogen that causes high rates of morbidity and mortality in farmed swine. We performed a molecular characterization of antimicrobial resistance genes harbored byH. parasuisfrom pig farms in China.MethodsWe screened 143H. parasuisisolates for antimicrobial susceptibility against six fluoroquinolone antibiotics testing by the broth microdilution method, and the presence of 64 antimicrobial resistance genes by PCR amplification and DNA sequence analysis. We determined quinolone resistance determining region mutations of DNA gyrase (gyrAandgyrB) and topoisomerase IV (parCandparE). The genetic relatedness among the strains was analyzed by pulsed-field gel electrophoresis.ResultsSusceptibility test showed that all isolates were low resistance to lomefloxacin (28.67%), levofloxacin (20.28%), norfloxacin (22.38%), ciprofloxacin (23.78%), however, high resistance levels were found to nalidixic acid (82.52%) and enrofloxacin (55.94%). In addition, we found 14 antimicrobial resistance genes were present in these isolates, includingblaTEM-1, blaROB-1,ermB, ermA, flor, catl, tetB, tetC, rmtB, rmtD, aadA1, aac(3′)-llc, sul1, and sul2genes. Interestingly, one isolate carried five antibiotic resistance genes (tetB, tetC, flor, rmtB, sul1). The genestetB,rmtB,andflorwere the most prevalent resistance genes inH. parasuisin China. Alterations in thegyrAgene (S83F/Y, D87Y/N/H/G) were detected in 81% of the strains andparCmutations were often accompanied by agyrAmutation. Pulsed-field gel electrophoresis typing revealed 51 unique patterns in the isolates carrying high-level antibiotic resistance genes, indicating considerable genetic diversity and suggesting that the genes were spread horizontally.DiscussionThe current study demonstrated that the high antibiotic resistance ofH. parasuisin piglets is a combination of transferable antibiotic resistance genes and multiple target gene mutations. These data provide novel insights for the better understanding of the prevalence and epidemiology of antimicrobial resistance inH. parasuis.


2017 ◽  
Author(s):  
Yongda Zhao ◽  
Lili Guo ◽  
Jie Li ◽  
Xianhui Huang ◽  
Binghu Fang

Background: Haemophilus parasuis is a common porcine respiratory disease that causes high rates of morbidity and mortality in farmed swine. We performed a molecular characterization of antimicrobial resistance genes harbored by H. parasuis from pig farms in China. Methods: We screened 143 H. parasuis isolates for the presence of 64 antimicrobial resistance genes by PCR amplification and DNA sequence analysis. We determined quinolone resistance determining region mutations of DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE). The genetic relatedness among the strains was analyzed by pulsed-field gel electrophoresis. Results: We found 14 antimicrobial resistance genes were present in these isolates, including TEM-1, ROB-1.ermB,ermA ,flor, catl,tetB,tetC, rmtB, rmtD, aadA1, aac(3’)-ⅡC, sul1, and sul2 genes. Interestingly, one isolate carried 5 antibiotic resistance genes (tetB, tetC, flor, rmtB, sul1). The genes tetB, rmtB, and flor were the most prevalent resistance genes in H. parasuis in China. Alterations in the gyrA gene (S83F/Y, D87Y/N/H/G) were detected in 81% of the strains and parC mutations were often accompanied by a gyrA mutation. pulsed-field gel electrophoresis typing revealed 51 unique patterns in the isolates carrying antibiotic resistance genes indicating considerable genetic diversity and suggesting the genes were spread horizontally. Discussion: The current study demonstrated that the high antibiotic resistance of H. parasuis in piglets is a combination of transferable antibiotic resistance genes and multiple target gene mutations. GyrA gene mutation also was the most important role in quinolone resistance. These data provide novel insights for the better understanding of the prevalence and epidemiology of antimicrobial resistance in H. parasuis.


2017 ◽  
Author(s):  
Yongda Zhao ◽  
Lili Guo ◽  
Jie Li ◽  
Xianhui Huang ◽  
Binghu Fang

Background: Haemophilus parasuis is a common porcine respiratory disease that causes high rates of morbidity and mortality in farmed swine. We performed a molecular characterization of antimicrobial resistance genes harbored by H. parasuis from pig farms in China. Methods: We screened 143 H. parasuis isolates for the presence of 64 antimicrobial resistance genes by PCR amplification and DNA sequence analysis. We determined quinolone resistance determining region mutations of DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE). The genetic relatedness among the strains was analyzed by pulsed-field gel electrophoresis. Results: We found 14 antimicrobial resistance genes were present in these isolates, including TEM-1, ROB-1.ermB,ermA ,flor, catl,tetB,tetC, rmtB, rmtD, aadA1, aac(3’)-ⅡC, sul1, and sul2 genes. Interestingly, one isolate carried 5 antibiotic resistance genes (tetB, tetC, flor, rmtB, sul1). The genes tetB, rmtB, and flor were the most prevalent resistance genes in H. parasuis in China. Alterations in the gyrA gene (S83F/Y, D87Y/N/H/G) were detected in 81% of the strains and parC mutations were often accompanied by a gyrA mutation. pulsed-field gel electrophoresis typing revealed 51 unique patterns in the isolates carrying antibiotic resistance genes indicating considerable genetic diversity and suggesting the genes were spread horizontally. Discussion: The current study demonstrated that the high antibiotic resistance of H. parasuis in piglets is a combination of transferable antibiotic resistance genes and multiple target gene mutations. GyrA gene mutation also was the most important role in quinolone resistance. These data provide novel insights for the better understanding of the prevalence and epidemiology of antimicrobial resistance in H. parasuis.


Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1025
Author(s):  
Shaohua Zhao ◽  
Cong Li ◽  
Chih-Hao Hsu ◽  
Gregory H. Tyson ◽  
Errol Strain ◽  
...  

Salmonella is a leading cause of bacterial infections in animals and humans. We sequenced a collection of 450 Salmonella strains from diseased animals to better understand the genetic makeup of their virulence and resistance features. The presence of Salmonella pathogenicity islands (SPIs) varied by serotype. S. Enteritidis carried the most SPIs (n = 15), while S. Mbandaka, S. Cerro, S. Meleagridis, and S. Havana carried the least (n = 10). S. Typhimurium, S. Choleraesuis, S. I 4,5,12:i:-, and S. Enteritidis each contained the spv operon on IncFII or IncFII-IncFIB hybrid plasmids. Two S. IIIa carried a spv operon with spvD deletion on the chromosome. Twelve plasmid types including 24 hybrid plasmids were identified. IncA/C was frequently associated with S. Newport (83%) and S. Agona (100%) from bovine, whereas IncFII (100%), IncFIB (100%), and IncQ1 (94%) were seen in S. Choleraesuis from swine. IncX (100%) was detected in all S. Kentucky from chicken. A total of 60 antimicrobial resistance genes (ARGs), four disinfectant resistances genes (DRGs) and 33 heavy metal resistance genes (HMRGs) were identified. The Salmonella strains from sick animals contained various SPIs, resistance genes and plasmid types based on the serotype and source of the isolates. Such complicated genomic structures shed light on the strain characteristics contributing to the severity of disease and treatment failures in Salmonella infections, including those causing illnesses in animals.


Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 430
Author(s):  
Wichai Santimaleeworagun ◽  
Praewdow Preechachuawong ◽  
Wandee Samret ◽  
Tossawan Jitwasinkul

Methicillin-resistant Staphylococcus aureus (MRSA) is mostly found in Thailand in the hospital as a nosocomial pathogen. This study aimed to report the genetic characterization of a clinical community-acquired MRSA (CA-MRSA) isolate collected from hospitalized patients in Thailand. Among 26 MRSA isolates, S. aureus no. S17 preliminarily displayed the presence of a staphylococcal cassette chromosome mec (SCCmec) type IV pattern. The bacterial genomic DNA was subjected to whole-genome sequencing. Panton–Valentine leukocidin (PVL) production, virulence toxins, and antibiotic resistance genes were identified, and multi-locus sequence typing (MLST) and spa typing were performed. The strain was matched by sequence to MLST type 2885 and spa type t13880. This strain carried type IV SCCmec with no PVL production. Five acquired antimicrobial resistance genes, namely blaZ, mecA, Inu(A), tet(K), and dfrG conferring resistance to β-lactams, lincosamides, tetracycline, and trimethoprim, were identified. The detected toxins were exfoliative toxin A, gamma-hemolysin, leukocidin D, and leukocidin E. Moreover, there were differences in seven regions in CR-MRSA no. S17 compared to CA-MRSA type 300. In summary, we have reported the ST2885-SCCmec IV CA-MRSA clinical strain in Thailand for the first time, highlighting the problem of methicillin resistance in community settings and the consideration in choosing appropriate antibiotic therapy.


2006 ◽  
Vol 74 (7) ◽  
pp. 3742-3755 ◽  
Author(s):  
Lakshmi Pillai ◽  
Jian Sha ◽  
Tatiana E. Erova ◽  
Amin A. Fadl ◽  
Bijay K. Khajanchi ◽  
...  

ABSTRACT Human diseases caused by species of Aeromonas have been classified into two major groups: septicemia and gastroenteritis. In this study, we reported the molecular and functional characterization of a new virulence factor, ToxR-regulated lipoprotein, or TagA, from a diarrheal isolate, SSU, of Aeromonas hydrophila. The tagA gene of A. hydrophila exhibited 60% identity with that of a recently identified stcE gene from Escherichia coli O157:H7, which encoded a protein (StcE) that provided serum resistance to the bacterium and prevented erythrocyte lysis by controlling classical pathway of complement activation by cleaving the complement C1-esterase inhibitor (C1-INH). We purified A. hydrophila TagA as a histidine-tagged fusion protein (rTagA) from E. coli DE3 strain using a T7 promoter-based pET30 expression vector and nickel affinity column chromatography. rTagA cleaved C1-INH in a time-dependent manner. The tagA isogenic mutant of A. hydrophila, unlike its corresponding wild-type (WT) or the complemented strain, was unable to cleave C1-INH, which is required to potentiate the C1-INH-mediated lysis of host and bacterial cells. We indeed demonstrated colocalization of C1-INH and TagA on the bacterial surface by confocal fluorescence microscopy, which ultimately resulted in increased serum resistance of the WT bacterium. Likewise, we delineated the role of TagA in contributing to the enhanced ability of C1-INH to inhibit the classical complement-mediated lysis of erythrocytes. Importantly, we provided evidence that the tagA mutant was significantly less virulent in a mouse model of infection (60%) than the WT bacterium at two 50% lethal doses, which resulted in 100% mortality within 48 h. Taken together, our data provided new information on the role of TagA as a virulence factor in bacterial pathogenesis. This is the first report of TagA characterization from any species of Aeromonas.


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