<i>Enterobacter</i>Species in a Pediatric Hospital: Horizontal Transfer or Selection in Individual Patients?

Man, Peter de; Veeke, Edwin van der; Leemreijze, Miranda; Leeuwen, Willem van; Vos, G F De; Anker, John van den; Verbrugh, Henri A.; Belkum, Alex van

doi:10.1086/322014

Cited by 23 publications

(13 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These data reflect the geno-and phenotypic heterogeneity of E. asburiae. In former studies, it played only a minor role as a clinical pathogen (9,12,40). In our study, one strain of the E. asburiae cluster (EN373) was isolated from the blood culture of a neonate (18).…”

Section: Discussionmentioning

confidence: 89%

Population Genetics of the Nomenspecies Enterobacter cloacae

Hoffmann

Roggenkamp

2003

Appl Environ Microbiol

236

270

View full text Add to dashboard Cite

The genetic heterogeneity of the nomenspecies Enterobacter cloacae is well known. Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter dissolvens, Enterobacter hormaechei, Enterobacter kobei, and Enterobacter nimipressuralis are closely related to it and are subsumed in the so-called E. cloacae complex. DNA-DNA hybridization studies performed previously identified at least five DNA-relatedness groups of this complex. In order to analyze the genetic structure and the phylogenetic relationships between the clusters of the nomenspecies E. cloacae, 206 strains collected from 22 hospitals, a veterinarian, and an agricultural center in 11 countries plus all 13 type strains of the genus and reference strain CDC 1347-71 R were examined with a combination of sequence and PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of the three housekeeping genes hsp60, rpoB, and hemB as well as ampC, the gene of a class C ␤-lactamase. Based on the neighbor-joining tree of the hsp60 sequences, 12 genetic clusters (I to XII) and an unstable sequence crowd (xiii) were identified. The robustness of the genetic clusters was confirmed by analyses of rpoB and hemB sequences and ampC PCR-RFLPs. Sequence crowd xiii split into two groups after rpoB analysis. Only three strains formed a cluster with the type strain of E. cloacae, indicating that the minority of isolates identified as E. cloacae truly belong to the species; 13% of strains grouped with other type strains of the genus, suggesting that the phenotypes of these species seem to be more heterogeneous than so far believed. Three clusters represented 70% of strains, but none of them included a type or reference strain. The genetic clustering presented in this study might serve as a framework for future studies dealing with taxonomic, evolutionary, epidemiological, or pathogenetic characteristics of bacteria belonging to the E. cloacae complex.Enterobacter cloacae has become increasingly important as a nosocomial pathogen, accounting for up to 5% of hospitalacquired septicemias, 5% of nosocomial pneumonias, 4% of nosocomial urinary tract infections, and 10% of postsurgical peritonitis cases (18,35,39). Besides its clinical significance, E. cloacae plays an important role as a pathogen in plants (2, 34) and insects (15) and is ubiquitous in the terrestrial and aquatic environments (22). This diversity of habitats is mirrored by the genetic variety of the nomenspecies E. cloacae, which has been demonstrated in several studies by biotyping and serotyping (16, 47), ribotyping and phage typing (46), pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) (18), and internal transcribed spacer-PCR and random amplification of polymorphic DNA (RAPD)-PCR (6). The 16S ribosomal DNA (rDNA) sequences of E. cloacae did not form a coherent cluster but built a patchy tree, in which the clusters of E. cloacae strains interfused with those of Enterobacter aerogenes, Escherichia coli, Citrobacter species, and Leclercia species. This refl...

show abstract

Section: Discussionmentioning

confidence: 89%

Population Genetics of the Nomenspecies Enterobacter cloacae

Hoffmann

Roggenkamp

2003

Appl Environ Microbiol

236

270

View full text Add to dashboard Cite

show abstract

“…However, in doing so it is assumed that patients are affected independently, which is not true for transmitted pathogens. The proportion of other patients being colonized, also called colonization pressure, amplifies the risk for noncolonized patients to acquire colonization (14)(15)(16)(17). Therefore, statistical tests may yield significant differences between two periods when these are in fact caused by chance.…”

Section: Discussionmentioning

confidence: 99%

How to assess the relative importance of different colonization routes of pathogens within hospital settings

Pelupessy

Bonten

Diekmann

2002

Proc. Natl. Acad. Sci. U.S.A.

103

View full text Add to dashboard Cite

The emergence of antibiotic resistance among nosocomial pathogens has reemphasized the need for effective infection control strategies. The spread of resistant pathogens within hospital settings proceeds along various routes of transmission and is characterized by large fluctuations in prevalence, which are typical for small populations. Identification of the most important route of colonization (exogenous by cross-transmission or endogenous caused by the selective pressure of antibiotics) is important for the design of optimal infection control strategies. Such identification can be based on a combination of epidemiological surveillance and costly and laborious as well as time-consuming methods of genotyping. Furthermore, analysis of the effects of interventions is hampered by the natural fluctuations in prevalence. To overcome these problems, we introduce a mathematical algorithm based on a Markov chain description. The input is longitudinal prevalence data only. The output is estimates of the key parameters characterizing the two colonization routes. The algorithm is tested on two longitudinal surveillance data sets of intensive care patients. The quality of the estimates is determined by comparing them to accurate estimates based on additional information obtained by genotyping. The results warrant optimism that this algorithm may help to quantify transmission dynamics and can be used to evaluate the effects of infection control interventions more carefully.

show abstract

“…Its multiplicity of resistance mechanisms may render this microbe less amenable to control by antibiotic cycling [10]. P .…”

Section: Introductionmentioning

confidence: 99%

Antimicrobial Susceptibility Patterns ofPseudomonas aeruginosafrom Diabetes Patients with Foot Ulcers

Sivanmaliappan¹,

Sevanan

2011

International Journal of Microbiology

View full text Add to dashboard Cite

Pseudomonas aeruginosa is an invasive organism that frequently causes severe tissue damage in diabetic foot ulcers. A major problem in P. aeruginosa infection may be that this pathogen exhibits a high degree of resistance to a broad spectrum of antibiotics. The study aimed to isolate and determine the antimicrobial susceptibility patterns of the P. aeruginosa population from diabetes patients with foot ulcers attending tertiary care hospitals in and around Coimbatore and their antimicrobial susceptibility pattern. The study was carried out at the Department of Microbiology, Dr. N.G.P. Arts and Science College, Coimbatore, for a period of one year (June 2006 to April 2007). The present study comprised 270 pus specimens collected from diabetic patients with foot ulcers. All pus samples were subjected to gram staining; bacterial culture and subsequently the antibiotic sensitivity to 15 different antibiotics for the confirmed P. aeruginosa were performed as per the standard procedures. Eighteen strains (14.28%) of P. aeruginosa from 270 diabetic foot ulcers were detected. Almost all the strains exhibited a varying degree of resistance to the antibiotics tested. Multidrug resistance for about 8 to 11 antibiotics was observed among the 55.5% of the isolates. Disk diffusion results show 100% resistance to ampicillin, cefoperazone, erythromycin, norfloxacin, and only cefotaxime, ciprofloxacin exhibited greater activity against Pseudomonas aeruginosa.

show abstract

EnterobacterSpecies in a Pediatric Hospital: Horizontal Transfer or Selection in Individual Patients?

Cited by 23 publications

References 17 publications

Population Genetics of the Nomenspecies Enterobacter cloacae

Population Genetics of the Nomenspecies Enterobacter cloacae

How to assess the relative importance of different colonization routes of pathogens within hospital settings

Antimicrobial Susceptibility Patterns ofPseudomonas aeruginosafrom Diabetes Patients with Foot Ulcers

Contact Info

Product

Resources

About