Silver Resistance Genes Are Overrepresented among Escherichia coli Isolates with CTX-M Production

Sütterlin, Stefan; Edquist, Petra; Sandegren, Linus; Adler, Marlen; Tängdén, Thomas; Drobni, Mirva; Olsén, Björn; Melhus, Åsa

doi:10.1128/aem.01803-14

Cited by 54 publications

(27 citation statements)

References 42 publications

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“…The MIC 50 values were 5.8 and 10.2 g/ml, respectively (MIC 50 values for AgNO 3 are provided in micrograms per milliliter to facilitate comparison with the existing literature; 1 g/ml Ϸ 6 M). These values are comparable to those obtained by others using the MIC; thus, for E. coli, the MIC for AgNO 3 ranged from 8 to 32 g/ml (19), and for S. aureus, the range was 8 to 16 g/ml (20). Therefore, the strains used in the present study may be considered highly sensitive with respect to Ag ϩ .…”

Section: Resultssupporting

confidence: 89%

Bacterial Silver Resistance Gained by Cooperative Interspecies Redox Behavior

Müller

2018

Antimicrob Agents Chemother

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Silver has emerged as an important therapeutic option for wound infections in recent years due to its broad-spectrum antimicrobial activity. The silver cation (Ag), but not the bulk metal (Ag), is highly toxic for most microorganisms, although resistance due to genetic modification or horizontal gene transfer does occur. , however, achieves silver resistance by producing the redox-active metabolite pyocyanin that reduces Ag to nontoxic Ag Pyocyanin also possesses broad-spectrum antimicrobial activity. Many microbial species reduce pyocyanin, which reduces molecular oxygen to antimicrobial hydrogen peroxide. In this study, it was hypothesized that both Ag and oxygen would act as competing terminal electron acceptors for pyocyanin, thus acting as a universal microbial protectant from Ag while avoiding hydrogen peroxide formation. and efficiently reduced pyocyanin and generated hydrogen peroxide, while Ag markedly reduced the amount of hydrogen peroxide produced. Although unable to reduce directly Ag to Ag on their own, and did so when pyocyanin was present, resulting in increased survival when exposed to Ag Coincubation experiments with either or with demonstrated increased survival for those species to Ag, but only if pyocyanin was present. These data demonstrate that microorganisms that display no intrinsic silver resistance may survive and proliferate under potentially toxic conditions, provided their environment contains a suitable redox-active metabolite-producing bacterium. Chronic wounds are often polymicrobial in nature, with pyocyanin-producing bacteria frequently being present; therefore, redox-based silver resistance may compromise treatment efforts.

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Section: Resultssupporting

confidence: 89%

Bacterial Silver Resistance Gained by Cooperative Interspecies Redox Behavior

Müller

2018

Antimicrob Agents Chemother

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“…Whether in presence or absence of nanosilver, SilB gene is constitutively expressed among Salmonella senftenberg (Losasso et al, 2014). SilE gene was common among E. coli isolates producing CTX-M after exposure to silver (Shutterlin et al, 2014). The previous findings are in agreement with our results as Sil operon plays a role in AgNPs resistance.…”

Section: Isolate No Resistance Patternsupporting

confidence: 92%

Molecular characterization of silver resistant E. coli strains isolated from patients suffering from diarrhea

Mohamed¹,

Ahmed²,

El-Baky³

2019

Afr. J. Microbiol. Res.

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Silver nanoparticles (AgNPs) are considered a good alternative for antibiotics due to emerging Multidrug Resistance (MDR) crisis. Resistance to AgNPs is approximately limited among Gram-positive and Gram-negative pathogens. Low toxicity to human cells permits its safe use as a new antimicrobial with broad spectrum. Bacterial cells are used as a factory for AgNPs synthesis supplying a powerful antimicrobial with eco-friendly way. In this study, MDR Escherichia coli strains were recovered from patients attending Minia University hospital. Biogenic synthesis of AgNPs was performed using E. coli cells. Transmission Electron Microscopy (TEM) was used to characterize AgNPs size and shape. Antibacterial activity of AgNPs was tested against the MDR E. coli isolates. Screening for Sil and Omp genes was done using polymerase chain reaction (PCR). A total of 13 MDR E. coli bacterial culture supernatant isolates were recovered from patients under study. Biosynthesis of AgNPs was observed after addition of supernatant to AgNO 3 by color change from yellow to brown. TEM characterization indicated the presence of silver nanoparticles with 15-75 nm particle size range. Eleven of MDR E. coli isolates were sensitive to biogenic AgNPs under study. SilB and SilE genes were encoded by the two AgNPs-resistant E. coli isolates which were negative for OmpF and OmpC genes, respectively demonstrating the role of Sil efflux pump genes and porin deficiency in AgNPs resistance. As indicated, the emergence of silver resistance due to the wide spread of biocides including silver has become a great challenge for the treatment of different infections.

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“…Likewise, the silA/pcoD -negative results seem to be more associated with E. aerogenes than EcC species (Table 1 ). There was a close association between the bla CTX−M gene and the silA (and pcoD ) genes among the isolates studied here, and this finding (silver-resistance genes and/or silver-resistance phenotype) was previously reported for clinical Escherichia coli isolates (Sütterlin et al, 2012 , 2014 ; Deus et al, 2017 ). Moreover, there have been reports of silver-resistant (and/or silA -positive) isolates associated with silver minimal inhibitory concentrations that could impact the management of non-invasive bacterial infections (such as those found among burn patients; Finley et al, 2015 ; Deus et al, 2017 ).…”

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confidence: 87%

Multidrug-Resistant CTX-M-(15, 9, 2)- and KPC-2-Producing Enterobacter hormaechei and Enterobacter asburiae Isolates Possessed a Set of Acquired Heavy Metal Tolerance Genes Including a Chromosomal sil Operon (for Acquired Silver Resistance)

et al. 2018

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Bacterial resistance to antibiotics is concern in healthcare-associated infections. On the other hand, bacterial tolerance to other antimicrobials, like heavy metals, has been neglected and underestimated in hospital pathogens. Silver has long been used as an antimicrobial agent and it seems to be an important indicator of heavy metal tolerance. To explore this perspective, we searched for the presence of acquired silver resistance genes (sil operon: silE, silS, silR, silC, silF, silB, silA, and silP) and acquired extended-spectrum cephalosporin and carbapenem resistance genes (blaCTX−M and blaKPC) in Enterobacter cloacae Complex (EcC) (n = 27) and Enterobacter aerogenes (n = 8) isolated from inpatients at a general hospital. Moreover, the genetic background of the silA (silver-efflux pump) and the presence of other acquired heavy metal tolerance genes, pcoD (copper-efflux pump), arsB (arsenite-efflux pump), terF (tellurite resistance protein), and merA (mercuric reductase) were also investigated. Outstandingly, 21/27 (78%) EcC isolates harbored silA gene located in the chromosome. Complete sil operon was found in 19/21 silA-positive EcC isolates. Interestingly, 8/20 (40%) E. hormaechei and 5/6 (83%) E. asburiae co-harbored silA/pcoD genes and blaCTX−M−(15,2,or9) and/or blaKPC−2 genes. Frequent occurrences of arsB, terF, and merA genes were detected, especially in silA/pcoD-positive, multidrug-resistant (MDR) and/or CTX-M-producing isolates. Our study showed co-presence of antibiotic and heavy metal tolerance genes in MDR EcC isolates. In our viewpoint, there are few studies regarding to bacterial heavy metal tolerance and we call attention for more investigations and discussion about this issue in different hospital pathogens.

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Silver Resistance Genes Are Overrepresented among Escherichia coli Isolates with CTX-M Production

Cited by 54 publications

References 42 publications

Bacterial Silver Resistance Gained by Cooperative Interspecies Redox Behavior

Bacterial Silver Resistance Gained by Cooperative Interspecies Redox Behavior

Molecular characterization of silver resistant E. coli strains isolated from patients suffering from diarrhea

Multidrug-Resistant CTX-M-(15, 9, 2)- and KPC-2-Producing Enterobacter hormaechei and Enterobacter asburiae Isolates Possessed a Set of Acquired Heavy Metal Tolerance Genes Including a Chromosomal sil Operon (for Acquired Silver Resistance)

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