Vancomycin Heteroresistance in Bloodstream Isolates of
            <i>Staphylococcus capitis</i>

D’Mello, D.; Daley, Andrew J; Rahman, Muhammad Shihab; Qu, Yue; Garland, Suzanne M.; Pearce, Christopher; Deighton, Margaret

doi:10.1128/jcm.00592-08

Cited by 39 publications

(55 citation statements)

References 19 publications

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“…We did not detect isolates expressing nonmecA-mediated resistance to oxacillin. High levels of resistance to erythromycin and clindamycin in S. epidermidis were reported by many studies (21,26). In the present study, 42 isolates (71.7%) were resistant to erythromycin, and only four (6.7%) were resistant or showed inducible resistance to clindamycin.…”

Section: Discussionmentioning

confidence: 47%

“…Based on MICs, no isolates of S. capitis displayed reduced susceptibility to vancomycin; however, this method may not detect small populations of resistant cells, which can only be detected by population analysis profiling. Our previous studies show that such populations do exist in S. capitis (26).…”

Section: Molecular Epidemiology Of Clinical S Capitis Isolates Over mentioning

confidence: 99%

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Differences between Two Clinical Staphylococcus capitis Subspecies as Revealed by Biofilm, Antibiotic Resistance, and Pulsed-Field Gel Electrophoresis Profiling

et al. 2013

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bCoagulase-negative staphylococci have been identified as major causes of late-onset neonatal bacteremia in neonatal intensive care units. Sixty isolates of Staphylococcus capitis obtained from blood cultures of neonates between 2000 and 2005 were examined in this study. Biochemical analysis confirmed that 52 of these isolates belonged to the subsp. urealyticus, and the remaining 8 belonged to the subsp. capitis. Isolates of the predominant subsp. urealyticus clones were characterized by their resistance to penicillin, erythromycin, and oxacillin and their biofilm formation ability, whereas subsp. capitis isolates were generally antibiotic susceptible and biofilm negative. Pulsed-field gel electrophoresis (PFGE) after SacII digestion separated the 60 isolates into five major clusters. Sequence analysis showed that, in S. capitis, the ica operon plus the negative regulator icaR was 4,160 bp in length. PCRs demonstrated the presence of the ica operon in all isolates. Further analysis of five isolates (two biofilm-positive subsp. urealyticus, one biofilm-negative subsp. urealyticus, and two biofilm-negative subsp. capitis) revealed that the ica operons were identical in all of the biofilm-positive subsp. urealyticus strains; however, the biofilm-negative isolates showed variations. The distinctive phenotypic and genotypic characteristics revealed by this study may affect the epidemiology of the two subspecies of S. capitis in the clinical setting. These results may provide a better understanding of the contribution of these two species to bloodstream infections in neonates.

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Section: Discussionmentioning

confidence: 47%

Section: Molecular Epidemiology Of Clinical S Capitis Isolates Over mentioning

confidence: 99%

Differences between Two Clinical Staphylococcus capitis Subspecies as Revealed by Biofilm, Antibiotic Resistance, and Pulsed-Field Gel Electrophoresis Profiling

et al. 2013

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“…Disc diffusion assays (3,14,18,55,(86)(87)(88)(89)(90)(91)(92) and Etest strips have been used to detect heteroresistance as recommended for traditional in vitro susceptibility testing (6,15,18,50,63,64,66,68,71,73,76,80,86,(88)(89)(90)(91)(93)(94)(95)(96)(97)(98)(99)(100)(101). Special Etest strips were developed for glycopeptide resistance detection (GRD Etest) (69,74,75,81,102).…”

Section: Disc Diffusion and Etest Assaysmentioning

confidence: 99%

“…A modified PAP assay comparing the area under the curve (PAP-AUC) of a given strain to that of a reference heteroresistant strain was used to determine S. aureus heteroresistance to vancomycin (67)(68)(69)(70)(71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81). PAP-AUC ratios between the test and control strains of Ͻ0.9, 0.9 to 1.3, and Ͼ1.3 were considered indicative of vancomycin-susceptible S. aureus, heterogeneous vancomycinintermediate S. aureus (hVISA), and vancomycin-intermediate S. aureus (VISA), respectively (67,72,74,76).…”

Section: Population Analysis Profilingmentioning

confidence: 99%

Antimicrobial Heteroresistance: an Emerging Field in Need of Clarity

2015

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SUMMARY “Heteroresistance” describes a phenomenon where subpopulations of seemingly isogenic bacteria exhibit a range of susceptibilities to a particular antibiotic. Unfortunately, a lack of standard methods to determine heteroresistance has led to inappropriate use of this term. Heteroresistance has been recognized since at least 1947 and occurs in Gram-positive and Gram-negative bacteria. Its clinical relevance may be considerable, since more resistant subpopulations may be selected during antimicrobial therapy. However, the use of nonstandard methods to define heteroresistance, which are costly and involve considerable labor and resources, precludes evaluating the clinical magnitude and severity of this phenomenon. We review the available literature on antibiotic heteroresistance and propose recommendations for definitions and determination criteria for heteroresistant bacteria. This will help in assessing the global clinical impact of heteroresistance and developing uniform guidelines for improved therapeutic outcomes.

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“…Therefore, vancomycin is often used as the first-line antimicrobial therapy. However, since the late 1980s, resistance to glycopeptides has been reported in CoNS (14)(15)(16)(17). This resistance appears to be endogenous, does not seem to be associated with plasmids or transposons, and can be selected for in vitro by exposure to teico-planin or vancomycin.…”

mentioning

confidence: 99%

Molecular Epidemiology of a Vancomycin-Intermediate Heteroresistant Staphylococcus epidermidis Outbreak in a Neonatal Intensive Care Unit

Chong

Quach

Blanchard

et al. 2016

Antimicrob Agents Chemother

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epidermidis CLABSIs were identified in two tertiary care NICUs in Quebec, Canada. Decreased vancomycin susceptibility was identified in about 88% of all collected strains using Etest methods. However, discrepancies were found according to the Etest and population analysis profiling-area under the concentration-time curve (PAP-AUC) methods used. All strains were susceptible to linezolid, and a few isolates were nonsusceptible to daptomycin. Great genetic diversity was observed within the collection, with 31 pulsed-field gel electrophoresis (PFGE) patterns identified. The outbreak strains were all determined to be heteroresistant to vancomycin and were polyclonal. The study identified two major clones, PFGE patterns E and G, which were found in both NICUs across the 5-year study period. This suggests the persistence of highly successful clones that are well adapted to the hospital environment. hV S. epidermidis seems more common than currently realized in the NICU, and certain hV S. epidermidis clones can become endemic to the NICU. The reservoirs for these clones remain unknown at this time, and identification of the reservoirs is needed to better understand the impact of hV S. epidermidis in the NICU and to inform infection prevention strategies. In addition, there is a need to investigate and validate hV determination protocols for different species of CoNS.

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Vancomycin Heteroresistance in Bloodstream Isolates of Staphylococcus capitis

Cited by 39 publications

References 19 publications

Differences between Two Clinical Staphylococcus capitis Subspecies as Revealed by Biofilm, Antibiotic Resistance, and Pulsed-Field Gel Electrophoresis Profiling

Differences between Two Clinical Staphylococcus capitis Subspecies as Revealed by Biofilm, Antibiotic Resistance, and Pulsed-Field Gel Electrophoresis Profiling

Antimicrobial Heteroresistance: an Emerging Field in Need of Clarity

Molecular Epidemiology of a Vancomycin-Intermediate Heteroresistant Staphylococcus epidermidis Outbreak in a Neonatal Intensive Care Unit

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