Subtractive Hybridization Yields a Silver Resistance Determinant Unique to Nosocomial Pathogens in the Enterobacter cloacae Complex

Kremer, Anita N.; Hoffmann, Harald

doi:10.1128/jcm.00885-12

Cited by 35 publications

(19 citation statements)

References 47 publications

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“…The K. pneumoniae outbreak in Uppsala was also caused by a global clone, ST16 (12), which in recent years has been associated with several clinically important carbapenemases (45). Interestingly, it has been suggested that resistance to silver ions represents a potent fitness factor in members of the Enterobacter cloacae complex (46).…”

Section: Discussionmentioning

confidence: 99%

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

Sütterlin

Edquist

Sandegren

et al. 2014

Appl Environ Microbiol

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Members of the Enterobacteriaceae with extended-spectrum beta-lactamases (ESBLs) of the CTX-M type have disseminated rapidly in recent years and have become a threat to public health. In parallel with the CTX-M type expansion, the consumption and widespread use of silver-containing products has increased. To determine the carriage rates of silver resistance genes in different Escherichia coli populations, the presence of three silver resistance genes (silE, silP, and silS) and genes encoding CTX-M-, TEM-, and SHV-type enzymes were explored in E. coli isolates of human (n ‫؍‬ 105) and avian (n ‫؍‬ 111) origin. The antibiotic profiles were also determined. Isolates harboring CTX-M genes were further characterized, and phenotypic silver resistance was examined. The silE gene was present in 13 of the isolates. All of them were of human origin. Eleven of these isolates harbored ESBLs of the CTX-M type (P ‫؍‬ 0.007), and eight of them were typed as CTX-M-15 and three as CTX-M-14. None of the silE-positive isolates was related to the O25b-ST131 clone, but 10 out of 13 belonged to the ST10 or ST58 complexes. Phenotypic silver resistance (silver nitrate MIC > 512 mg/liter) was observed after silver exposure in 12 of them, and a concomitant reduced susceptibility to piperacillin-tazobactam developed in three. In conclusion, 12% of the human E. coli isolates but none of the avian isolates harbored silver resistance genes. This indicates another route for or level of silver exposure for humans than that caused by common environmental contamination. Since silE-positive isolates were significantly more often found in CTX-M-positive isolates, it is possible that silver may exert a selective pressure on CTX-M-producing E. coli isolates.

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Section: Discussionmentioning

confidence: 99%

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

Sütterlin

Edquist

Sandegren

et al. 2014

Appl Environ Microbiol

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“…Similarly, the sil determinant has been associated with pathogenicity in the Enterobacter cloacae complex, where the presence of the genes conferring silver resistance was increased in isolates from hospital settings vs. strains associated with plants (Kremer and Hoffmann 2012). Although identification of the pco genes was not part of that study, their presence within the isolates harboring the full sil determinant is very likely based on the high rate of co-representation (Mourão et al 2015) (Table 1).…”

Section: Introductionmentioning

confidence: 99%

Survival in amoeba—a major selection pressure on the presence of bacterial copper and zinc resistance determinants? Identification of a “copper pathogenicity island”

Hao

Lüthje

Qin

et al. 2015

Appl Microbiol Biotechnol

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The presence of metal resistance determinants in bacteria usually is attributed to geological or anthropogenic metal contamination in different environments or associated with the use of antimicrobial metals in human healthcare or in agriculture. While this is certainly true, we hypothesize that protozoan predation and macrophage killing are also responsible for selection of copper/zinc resistance genes in bacteria. In this review, we outline evidence supporting this hypothesis, as well as highlight the correlation between metal resistance and pathogenicity in bacteria. In addition, we introduce and characterize the Bcopper pathogenicity island^identified in Escherichia coli and Salmonella strains isolated from copper-and zinc-fed Danish pigs.

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“…Homologues of the sil system have been detected using silspecific primers in IncH1-2 group plasmids from Gramnegative bacteria (Gupta et al, 2001), in oral bacteria (Davis et al, 2005), in nosocomial isolates of Enterobacter cloacae (Kremer & Hoffmann, 2012), a silver-resistant Enterobacter cloacae leg ulcer isolate (Sütterlin et al, 2012), some Gram-negative bacteria isolated from wounds ) and, surprisingly, in S. aureus (Loh et al, 2009). There are also some reports of silver-resistant pathogens which carry the sil genes that were isolated from burns units and even from the silver-containing burns creams (Pirnay et al, 2003).…”

Section: Silver Tolerance and Resistancementioning

confidence: 99%

Bacterial antimicrobial metal ion resistance

Hobman

Crossman

2015

Journal of Medical Microbiology

317

217

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Metals such as mercury, arsenic, copper and silver have been used in various forms as antimicrobials for thousands of years with until recently, little understanding of their mode of action. The discovery of antibiotics and new organic antimicrobial compounds during the twentieth century saw a general decline in the clinical use of antimicrobial metal compounds, with the exception of the rediscovery of the use of silver for burns treatments and niche uses for other metal compounds. Antibiotics and new antimicrobials were regarded as being safer for the patient and more effective than the metal-based compounds they supplanted. Bacterial metal ion resistances were first discovered in the second half of the twentieth century. The detailed mechanisms of resistance have now been characterized in a wide range of bacteria. As the use of antimicrobial metals is limited, it is legitimate to ask: are antimicrobial metal resistances in pathogenic and commensal bacteria important now? This review details the new, rediscovered and 'never went away' uses of antimicrobial metals; examines the prevalence and linkage of antimicrobial metal resistance genes to other antimicrobial resistance genes; and examines the evidence for horizontal transfer of these genes between bacteria. Finally, we discuss the possible implications of the widespread dissemination of these resistances on re-emergent uses of antimicrobial metals and how this could impact upon the antibiotic resistance problem. IntroductionMetals and metalloids have a long empirical history of human usage in medicine and agriculture (as reviewed below), despite problems of host toxicity or doubts about their efficacy. Even now, a few toxic metal(loid) compounds are still first-line drugs or preferred-choice chemotherapeutics or antimicrobials, although the use of most of the previously popular antimicrobial metal(loid)s, such as mercury and arsenic/antimony compounds, has been reduced or phased out in the past 50 or so years. Other metals, such as silver and copper, still have limited uses in agriculture and medicine, but are also increasingly being included in consumer products, from clothing to computer keyboards, and are being promoted as useful additions to our arsenal of antimicrobials. Against this background of their current usage, it is reasonable to ask: what is the relevance of antimicrobial metals and bacterial resistances to them to medical microbiology in the twentyfirst century?Any attempt to address this question must be set against the backdrop of widely known problems and opportunities. We are faced with new and emerging opportunistic nosocomial and community-acquired pathogens; and increasing epidemic and pandemic multidrug-resistant (MDR) pathogens. There is a recognition that the antibiotic discovery pipeline has not delivered significant quantities of new antibiotics in the past few decades, and new formulations and uses for antimicrobial metals as weapons in the antimicrobial armoury are being proposed (Department of Health, 2013;Lemire et al., 2013). ...

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Subtractive Hybridization Yields a Silver Resistance Determinant Unique to Nosocomial Pathogens in the Enterobacter cloacae Complex

Cited by 35 publications

References 47 publications

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

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

Survival in amoeba—a major selection pressure on the presence of bacterial copper and zinc resistance determinants? Identification of a “copper pathogenicity island”

Bacterial antimicrobial metal ion resistance

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