Latest News on Enterobacteriaceae Research: Jan – 2020

Identification of Enterobacteriaceae.

Ewing has delivered to bear his wide experience within the field of the Enterobacteriaceae, particularly Jn their complex serological interrelationships, within the third edition of this work. The previous editions are essential handbooks altogether bacteriological laboratories where these organisms are studied in any detail, and lots of of the new and important discoveries in these fields are included during this edition.

In the first 4 chapters, general points of taxonomy, nomenclature, and therefore the use of media for the isolation and characterization of representatives of this family are discussed and an outline is given of all the kinds of antigen likely to be encountered during this group. Full biochemical data on the kinds of reaction of all the tribes, genera, species and even some subspecies are given. The results aren’t given within the usual + or – system only but expressed as percentages also. [1]

Global Spread of Carbapenemase-producing Enterobacteriaceae

Carbapenemases increasingly are reported in Enterobacteriaceae within the past 10 years. Klebsiella pneumoniae carbapenemases are reported within the us then worldwide, with a marked endemicity a minimum of within the us and Greece. Metallo-enzymes (Verona integron–encoded metallo-β-lactamase, IMP) even have been reported worldwide, with a better prevalence in southern Europe and Asia. Carbapenemases of the oxacillinase-48 type are identified mostly in Mediterranean and European countries and in India. Recent identification of latest Delhi metallo-β-lactamase-1 producers, originally within the uk , India, and Pakistan and now worldwide, is worrisome. Detection of infected patients and carriers with carbapenemase producers is important for prevention of their spread. Identification of the carbapenemase genes relies totally on molecular techniques, whereas detection of carriers is feasible by using screening culture media. [2]

Resistance Plasmid Families in Enterobacteriaceae

Bacteria carry extrachromosomal, self-replicating genetic elements called plasmids. A plasmid is defined as a double-stranded, circular DNA molecule capable of autonomous replication. By definition, plasmids don’t carry genes essential for the expansion of host cells under nonstressed conditions (109). Plasmids have systems which guarantee their autonomous replication but even have mechanisms controlling their copy number and ensuring stable inheritance during cellular division . they will promote lateral transfer among bacteria of various genera and kingdoms through the conjugation process. Many plasmids encode addiction systems generally supported toxin-antitoxin factors, which are ready to kill daughter cells that don’t inherit the plasmid during cellular division (46). [3]

Dietary L-serine confers a competitive fitness advantage to Enterobacteriaceae in the inflamed gut

Metabolic reprogramming is related to the difference of host cells to the disease environment, like inflammation and cancer. However, little is understood about microbial metabolic reprogramming or the role it plays in regulating the fitness of commensal and pathogenic bacteria within the gut. Here, we report that intestinal inflammation reprograms the metabolic pathways of Enterobacteriaceae, like Escherichia coli LF82, within the gut to adapt to the inflammatory environment. We found that E. coli LF82 shifts its metabolism to catabolize L-serine within the inflamed gut so as to maximise its growth potential. However, L-serine catabolism features a minimal effect on its fitness within the healthy gut. In fact, the absence of genes involved in L-serine utilization reduces the competitive fitness of E. [4]

Evaluation of the NDP Test, a Novel Chromogenic Test for Rapid Detection of Extended Spectrum β-Lactamase Producing Enterobacteriaceae

Background: the first detection of extended spectrum β-lactamase (ESBL) producers in clinical microbiology is now of great importance to optimize appropriate therapeutic schemes and to enhance the patient outcome. The ESBL NDP (Nordmann/Dortet/Poirel) test has been recently developed for the first detection of ESBL producing organisms. it’s supported the biochemical detection of the hydrolysis of the β-lactam ring of cefotaxime (a broad spectrum cephalosporin).

Aims: This study was done to guage the performance of NDP test in detection of ESBL producing organism directly from urine samples and blood cultures.

Place and Duration of Study: this is often a Seven-months Cross sectional study conducted in general medicine and Medical Microbiology & Immunology departments, Benha University, Egypt. [5]

Reference

[1] Edwards, P.R. and Ewing, W.H., 1972. Identification of enterobacteriaceae. Identification of Enterobacteriaceae., (Third edition). (Web Link)

[2] Nordmann, P., Naas, T. and Poirel, L., 2011. Global spread of carbapenemase-producing Enterobacteriaceae. Emerging infectious diseases, 17(10), (Web Link)

[3] Carattoli, A., 2009. Resistance plasmid families in Enterobacteriaceae. Antimicrobial agents and chemotherapy, 53(6), (Web Link)

[4] Dietary L-serine confers a competitive fitness advantage to Enterobacteriaceae in the inflamed gut
Sho Kitamoto, Christopher J. Alteri, […]Nobuhiko Kamada
Nature Microbiology volume 5, (Web Link)

[5] Saeed, A. M., Tabl, H. A. and Mogahed, M. M. (2017) “Evaluation of the NDP Test, a Novel Chromogenic Test for Rapid Detection of Extended Spectrum β-Lactamase Producing Enterobacteriaceae”, Microbiology Research Journal International, 18(6), (Web Link)

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