Correlation of typing methods for Acinetobacter isolates from hospital outbreaks

Dijkshoorn, Lenie; Aucken, Hazel M.; Gerner‐Smidt, Peter; Kaufmann, M. E.; Ursing, Jan; Pitt, T. L.

doi:10.1128/jcm.31.3.702-705.1993

Cited by 101 publications

(53 citation statements)

References 19 publications

(23 reference statements)

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“…This epidemiological working definition is less stringent than the definitions of a clone used by microbial geneticists [31][32][33][34][35]. The interest in clones has increased over the past decades, due to the emergence of multiresistant or highly virulent clones of pathogenic bacteria that have become widespread and seem to remain stable for prolonged periods [24][25][26][33][34][35][36][37][38]. Ørskov and Ørskov [31] proposed the following formulation: 'The word clone will be used to denote bacterial cultures isolated independently from different sources, in different locations, and perhaps at different times, but still showing so many identical phenotypic and genotypic traits that the most likely explanation of this identity is a common origin.'…”

Section: E F I N I T I O N S R E G a R D I N G I S O L A T E R E L mentioning

confidence: 99%

“…Unfortunately, new molecular typing methods are often proposed for general use without sufficient prior critical evaluation. For example, they may not have been standardised, a minimal number of isolates may have been used for validation, their agreement with epidemiological data may not have been assessed, or the suitability of a specific method-microbe combination for a specific bacterial taxon may not have been addressed [19][20][21][22][23][24][25][26][27][28]. Finally, basic terminology-including fundamental terms such as 'isolate', 'strain', 'type' or 'clone'-is often used differently by different workers in the field of bacterial epidemiology.…”

Section: Introductionmentioning

confidence: 99%

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Guidelines for the validation and application of typing methods for use in bacterial epidemiology

Belkum

Tassios

Dijkshoorn

et al. 2007

Clinical Microbiology and Infection

677

516

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For bacterial typing to be useful, the development, validation and appropriate application of typing methods must follow unified criteria. Over a decade ago, ESGEM, the ESCMID (Europen Society for Clinical Microbiology and Infectious Diseases) Study Group on Epidemiological Markers, produced guidelines for optimal use and quality assessment of the then most frequently used typing procedures. We present here an update of these guidelines, taking into account the spectacular increase in the number and quality of typing methods made available over the past decade. Newer and older, phenotypic and genotypic methods for typing of all clinically relevant bacterial species are described according to their principles, advantages and disadvantages. Criteria for their evaluation and application and the interpretation of their results are proposed. Finally, the issues of reporting, standardisation, quality assessment and international networks are discussed. It must be emphasised that typing results can never stand alone and need to be interpreted in the context of all available epidemiological, clinical and demographical data relating to the infectious disease under investigation. A strategic effort on the part of all workers in the field is thus mandatory to combat emerging infectious diseases, as is financial support from national and international granting bodies and health authorities.

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Section: E F I N I T I O N S R E G a R D I N G I S O L A T E R E L mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Guidelines for the validation and application of typing methods for use in bacterial epidemiology

Belkum

Tassios

Dijkshoorn

et al. 2007

Clinical Microbiology and Infection

677

516

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“…baumannii biotype 9 in their system (16) and in all the published studies where biotyping has been done this biotype dominates, making up 2WO% of all A. baumannii isolates. In addition, DNA group 3 strains may also be misidentified as A. baumannii (9,16). In the second part of this study, all 23 strains from the Acb complex were identified genotypically.…”

Section: Discussionmentioning

confidence: 95%

Acinetobacterin Denmark: I. Taxonomy, antibiotic susceptibility, and pathogenicity of 112 clinical strains

Gerner‐Smidt

Frederiksen

1993

Apmis

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One hundred and twelve clinical strains of Acinetobacter were collected during a 7‐month period in 1990–1991 from Danish clinical microbiology departments. According to the old notation, 37 strains were biovar anitratus and 75 b.lwoffii. Using the newest terminology, 35 strains were unambiguously identified as the species A. haemolyticus, A. johnsonii, A. radioresistens, and as the unnamed phenons 6, 10, and 14, by a numerical approach using a simplified phenotypical identification scheme. Most of the remaining strains were identified to the genotypically heterogeneous A. calcoaceticus‐A. baumannii complex and the A. lwoffii phenotype. Sixteen strains (14%) were left unidentified. Eight A. lwoffii strains were glucose‐oxidizing and were thus classified as b. anitratus using the old terminology. The strains were tested for susceptibility to ampicillin, piperacillin, ticarcillin, cefotaxime, ceftazidime, imipenem, gentamicin, tetracycline, sulphonamide, and nalidixic acid. All strains were susceptible to imipenem. The susceptibility to the remaining β‐lactams was variable, the A. lwoffii isolates being the most and the A. calcoaceticus‐A. baumannii complex strains the least susceptible. All non‐A. calcoaceticus‐A. baumannii complex strains were susceptible to all other antibiotics tested, except for one A. lwoffii strain that was sulphonamide resistant. Twenty‐two percent of the strains in the A. calcoaceticus‐A. baumannii complex showed reduced susceptibility or resistance to gentamicin, but only sporadic resistance to sulphonamides, tetracyclines, and nalidixic acid. Eight infections were recorded: three cases of septicaemia, three cases of peritonitis related to continuous ambulatory peritoneal dialysis, and two cases of recurrent urinary tract infection. No epidemics were detected.

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“…DNA-DNA hybridization studies have shown that there are at least 19 DNA groups (genomic species) within the genus Acinetobacter (7,8,17,38). Strains belonging to some of these groups are so similar that phenotypic differentiation between them is not always possible (12,18). These phenotypically similar but genotypically distinct DNA hybridization groups have been designated the Acinetobacter calcoaceticus-A.…”

mentioning

confidence: 99%

“…This complex currently comprises DNA group 1, A. calcoaceticus sensu stricto Bouvet and Grimont (7); DNA group 2, A. baumannii; unnamed DNA group 3 (7); unnamed DNA group 13 (38); and two more as yet unnamed DNA groups (17). With the exception of DNA group 1, which is regarded as an environmental species, each genomic species within the complex has been linked to nosocomial infections (12,17,26). It is thus essential that typing schemes used for epidemiological studies be able to distinguish between isolates in the A. calcoaceticus-A.…”

mentioning

confidence: 99%

Validation of use of whole-cell repetitive extragenic palindromic sequence-based PCR (REP-PCR) for typing strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and application of the method to the investigation of a hospital outbreak

et al. 1996

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Acinetobacter spp. are being reported with increasing frequency as causes of nosocomial infection. In order to identify reservoirs of infection as quickly as possible, a rapid typing method that can differentiate epidemic strains from environmental and nonepidemic strains is needed. In 1993, a cluster of Acinetobacter baumannii isolates from five patients in the adult intensive therapy unit of our tertiary-care teaching hospital led us to develop and optimize a rapid repetitive extragenic palindromic sequence-based PCR (REP-PCR) typing protocol for members of the Acinetobacter calcoaceticus-A. baumannii complex that uses boiled colonies and consensus primers aimed at repetitive extragenic palindromic sequences. Four of the five patient isolates gave the same REP-PCR typing pattern as isolates of A. baumannii obtained from the temperature probe of a Bennett humidifier; the fifth isolate had a unique profile. Disinfection of the probe with 70% ethanol, as recommended by the manufacturer, proved ineffective, as A. baumannii with the same REP-PCR pattern was isolated from it 10 days after cleaning, necessitating a change in our decontamination procedure. Results obtained with REP-PCR were subsequently confirmed by ribotyping. To evaluate the discriminatory power (D) of REP-PCR for typing members of the A. calcoaceticus-A. baumannii complex, compared with that of ribotyping, we have applied both methods to a collection of 85 strains that included representatives of six DNA groups within the complex. Ribotyping using EcoRI digests yielded 53 patterns (D ‫؍‬ 0.98), whereas 68 different REP-PCR patterns were observed (D ‫؍‬ 0.99). By computer-assisted analysis of gel images, 74 patterns were observed with REP-PCR (D ‫؍‬ 1.0). Overall, REP-PCR typing proved to be slightly more discriminatory than ribotyping. Our results indicate that REP-PCR typing using boiled colonies is a simple, rapid, and effective means of typing members of the A. calcoaceticus-A. baumannii complex.

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Correlation of typing methods for Acinetobacter isolates from hospital outbreaks

Cited by 101 publications

References 19 publications

Guidelines for the validation and application of typing methods for use in bacterial epidemiology

Guidelines for the validation and application of typing methods for use in bacterial epidemiology

Acinetobacterin Denmark: I. Taxonomy, antibiotic susceptibility, and pathogenicity of 112 clinical strains

Validation of use of whole-cell repetitive extragenic palindromic sequence-based PCR (REP-PCR) for typing strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and application of the method to the investigation of a hospital outbreak

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