Evaluation of Multiple Methods for Detection of Gastrointestinal Colonization of Carbapenem-Resistant Organisms from Rectal Swabs

Rectal swabs from high-risk patients were screened for carbapenem-resistant organisms (CROs) using several methods. The direct MacConkey plate method was the most sensitive for CROs (95%), while chromID CARBA and the Check-Direct CPE screen assay were the most sensitive for the detection of carbapenemase-producing organisms (CPOs) (100%; allblaKPC). All methods had a specificity of >90% for CROs, and for CPOs, the specificity ranged from 85 to 98%. Broth enrichment methods performed poorly compared to direct inoculation methods, negating the need for the broth enrichment step.

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A new selective broth enrichment automated method for detection of carbapenem-resistant Enterobacteriaceae from rectal swabs

Journal of Microbiological Methods ◽

10.1016/j.mimet.2018.03.002 ◽

2018 ◽

Vol 147 ◽

pp. 66-68 ◽

Cited By ~ 3

Author(s):

Fabio Arena ◽

Tommaso Giani ◽

Alberto Antonelli ◽

Olga Lorenza Colavecchio ◽

Patrizia Pecile ◽

...

Keyword(s):

Carbapenem Resistant ◽

Automated Method ◽

Rectal Swabs ◽

Broth Enrichment ◽

Carbapenem Resistant Enterobacteriaceae

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Kpi, a chaperone-usher pili system associated with the worldwide-disseminated high-risk cloneKlebsiella pneumoniaeST-15

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1921393117 ◽

2020 ◽

Vol 117 (29) ◽

pp. 17249-17259

Author(s):

Eva Gato ◽

Juan Carlos Vázquez-Ucha ◽

Soraya Rumbo-Feal ◽

Laura Álvarez-Fraga ◽

Juan A. Vallejo ◽

...

Keyword(s):

Phylogenetic Analysis ◽

High Risk ◽

Antimicrobial Resistance ◽

Galleria Mellonella ◽

Carbapenem Resistant ◽

Defective Mutant ◽

Gastrointestinal Colonization ◽

Sequence Types ◽

Host Tissues

Control of infections caused by carbapenem-resistantKlebsiella pneumoniaecontinues to be challenging. The success of this pathogen is favored by its ability to acquire antimicrobial resistance and to spread and persist in both the environment and in humans. The emergence of clinically important clones, such as sequence types 11, 15, 101, and 258, has been reported worldwide. However, the mechanisms promoting the dissemination of such high-risk clones are unknown. Unraveling the factors that play a role in the pathobiology and epidemicity ofK. pneumoniaeis therefore important for managing infections. To address this issue, we studied a carbapenem-resistant ST-15K. pneumoniaeisolate (Kp3380) that displayed a remarkable adherent phenotype with abundant pilus-like structures. Genome sequencing enabled us to identify a chaperone-usher pili system (Kpi) in Kp3380. Analysis of a largeK. pneumoniaepopulation from 32 European countries showed that the Kpi system is associated with the ST-15 clone. Phylogenetic analysis of the operon revealed that Kpi belongs to the little-characterized γ2-fimbrial clade. We demonstrate that Kpi contributes positively to the ability ofK. pneumoniaeto form biofilms and adhere to different host tissues. Moreover, the in vivo intestinal colonizing capacity of the Kpi-defective mutant was significantly reduced, as was its ability to infectGalleria mellonella. The findings provide information about the pathobiology and epidemicity of Kpi+K. pneumoniaeand indicate that the presence of Kpi may explain the success of the ST-15 clone. Disrupting bacterial adherence to the intestinal surface could potentially target gastrointestinal colonization.

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Epidemiology of Glycopeptide-Resistant Enterococci Colonizing High-Risk Patients in Hospitals in Johannesburg, Republic of South Africa

Journal of Clinical Microbiology ◽

10.1128/jcm.38.2.905-909.2000 ◽

2000 ◽

Vol 38 (2) ◽

pp. 905-909 ◽

Cited By ~ 13

Author(s):

Anne von Gottberg ◽

Wim van Nierop ◽

Adriano Dusé ◽

Marlene Kassel ◽

Kerrigan McCarthy ◽

...

Keyword(s):

South Africa ◽

High Risk ◽

Enterococcus Faecium ◽

Prevalence Study ◽

Glycopeptide Resistance ◽

High Risk Patients ◽

Rectal Swabs ◽

Risk Patients ◽

The Republic ◽

Clonal Spread

Recent cases of infections caused by glycopeptide-resistant enterococci (GRE) have highlighted the emergence of these organisms in the Republic of South Africa. During May 1998 we conducted a prevalence study in four hospitals in Johannesburg and obtained 184 rectal swabs from patients identified as being at high risk for GRE colonization. Twenty enterococcal isolates showing various glycopeptide resistance genotypes were recovered: 3 Enterococcus faecium vanAisolates, 10 E. faecium vanB isolates, 6 E. gallinarum vanC1 isolates, and 1 E. avium vanAisolate. Macrorestriction analysis was used to demonstrate the clonal spread of GRE strains within hospitals. Evidence also demonstrated the likely persistence of the original E. faecium vanA isolate associated with the first confirmed death contributed to by GRE infection in South Africa in March 1997.

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Evaluation of the Direct MacConkey Method for Identification of Carbapenem-Resistant Gram-Negative Organisms from Rectal Swabs: Reevaluating Zone Diameter Cutoffs

Journal of Clinical Microbiology ◽

10.1128/jcm.01127-19 ◽

2019 ◽

Vol 57 (12) ◽

Cited By ~ 1

Author(s):

Meklit Workneh ◽

Ruibin Wang ◽

Abida Q. Kazmi ◽

Krizia K. Chambers ◽

Belita N. A. Opene ◽

...

Keyword(s):

Operating Characteristic ◽

High Sensitivity ◽

Roc Curves ◽

Plate Method ◽

Optimal Method ◽

Confirmatory Testing ◽

Zone Diameter ◽

Carbapenem Resistant ◽

Gram Negative Organisms ◽

Gastrointestinal Colonization

ABSTRACT The optimal method to screen for gastrointestinal colonization with carbapenem-resistant organisms (CRO) has yet to be established. The direct MacConkey (direct MAC) plate method demonstrates high sensitivity for CRO detection, but established zone diameter (ZD) criteria for ertapenem (≤27 mm) and meropenem (≤32 mm) result in high rates of false positives upon confirmatory testing. To increase specificity, we screened for CRO in two high-risk wards using the direct MAC plate method, recorded ZDs for each sample, and generated receiver operating characteristic (ROC) curves to evaluate the optimal ZD cutoff criteria. Of 6,868 swabs obtained over an 18-month period, 4,766 (69%) had growth on MAC plates, and 2,500 (36%) met criteria for further evaluation based on previously established ZDs around the carbapenem disks. A total of 812 (12%) swabs were confirmed positive for at least one CRO and included 213 (3%) carbapenemase-producing organisms (CPO), resulting in a specificity of 78% for the direct MAC plate method. Reducing the ertapenem and meropenem ZDs to ≤25 mm improved specificity to 83%, decreasing the confirmatory testing workload by 32%. The sensitivities with the lower ZD criteria were 89% for CRO and 94% for CPO, respectively. The direct MAC plate method criteria for CRO testing can be modified to balance the sensitivity and specificity of CRO while reducing the burden on clinical microbiology laboratories. These modifications can be particularly helpful in regions with a low CRO prevalence.

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