Abstract
Introduction: The emergence and spread of isolated carriers of extended-spectrum beta-lactamase (ESBL) have complicated the treatment of nosocomial infections, since its production is not easily identified by the sensitivity tests, routinely performed in clinical laboratories, leading to difficulties in the hospital control of resistant microorganisms and antibiotics misuse. Objective: The objective of this study was to analyze the resistance profile and the frequency of ESBL in Gram-negative bacteria isolated from blood cultures. A hundred bacterial samples from blood cultures of adult patients were analyzed, which were phenotypically identified by biochemical tests of carbohydrates fermentation and submitted to determination of the resistance profile by disc diffusion test and ESBL screening by disc approximation and disc replacement methods. Results: Among the bacterial samples tested, 30 were identified as Gram-negative bacteria, predominantly by Proteus mirabilis, Pantoea agglomerans, and Escherichia coli. Of these, 73.33% were positive for the detection of ESBL by phenotypic tests, and was found mainly in Pantoea agglomerans, Proteus mirabilis, and Enterobacter cloacae. Conclusion: The increase in the occurrence of ESBL in different Enterobacteriaceae shows the importance of the amplification of detection in other species than Escherichia coli or Klebsiella sp., so that the assistance to the patient is not restrained, since these resistant bacteria cannot be detected by the laboratories. Considering the frequency of ESBL in this study, we highlight the importance of its detection, aiming to its contribution to the development of improvements in the health care policies of hospitals.
Highlights
The emergence and spread of isolated carriers of extended-spectrum beta-lactamase (ESBL) have complicated the treatment of nosocomial infections, since its production is not identified by the sensitivity tests, routinely performed in clinical laboratories, leading to difficulties in the hospital control of resistant microorganisms and antibiotics misuse
One of the main mechanisms of bacterial resistance is the production of extended-spectrum beta-lactamases (ESBL), enzyme mediated by non-inducible plasmid gene, capable of hydrolyzing the oxyimino-beta-lactams chain present in the chemical structure of beta-lactams, inactivating them and providing greater bacterial resistance, which extends its spectrum of activity to the broad-spectrum antimicrobials[11, 21]
According to the interpretation of biochemical tests, bacterial samples were classified into five distinct species, with the predominance of Proteus mirabilis (23.33%), Pantoea agglomerans (20%), Escherichia coli (16.66%), and Enterobacter cloacae (10%), and a variety of other bacterial species, such as Proteus penneri (6.66%), Acinetobacter sp. (6.66%), Enterobacter gergoviae (6.66%), Enterobacter sakazakii (6.66%), and Pseudomonas sp. (3.33%) (Figure 1)
Summary
The emergence and spread of isolated carriers of extended-spectrum beta-lactamase (ESBL) have complicated the treatment of nosocomial infections, since its production is not identified by the sensitivity tests, routinely performed in clinical laboratories, leading to difficulties in the hospital control of resistant microorganisms and antibiotics misuse. Objective: The objective of this study was to analyze the resistance profile and the frequency of ESBL in Gram-negative bacteria isolated from blood cultures. Results: Among the bacterial samples tested, 30 were identified as Gram-negative bacteria, predominantly by Proteus mirabilis, Pantoea agglomerans, and Escherichia coli. ESBLs are derived from genetic mutations (temoneira [TEM] and sulfidril variable [SHV]), and are found mainly in Escherichia coli and Klebsiella sp., but can be detected in Proteus mirabilis, Enterobacter sp., Acinetobacter sp., First submission on 04/11/14; last submission on 28/11/14; accepted for publication on 08/12/14; published on 20/12/14 1. PhD in Biological Sciences by Pernambuco Federal University (UFPE); teaching at ASCES, Caruaru-PE
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