<abstract xmlns="http://www.w3.org/1999/xhtml"><p><italic>Enterococcus faecalis</italic> and <italic>Enterococcus faecium</italic> are among the main agents associated with nosocomial infections with high mortality in immunocompromised patients. Antibiotic resistance, especially against gentamicin and vancomycin among <italic>Enterococci</italic>, is a risk factor that could increase the morbidity and mortality rate. 179 <italic>Enterococci</italic> isolates from burn patients were included in this study. Antibiotic susceptibility testing was done using the disk diffusion test and minimum inhibitory concentration (MIC) was evaluated by agar microdilution. Vancomycin and gentamicin resistance associated genes including <italic>vanA</italic>, <italic>vanB</italic>, <italic>vanC</italic>, <italic>aac (6’)-Ie aph(2’’), aph(3’)-IIIa</italic> and <italic>ant(4’)-Ia</italic> were detected by PCR and their statistical relation with antibiotic resistance was evaluated. <italic>E. faecalis</italic> was the more prevalent strain among our local isolates and showed a higher antibiotic resistance in comparison to <italic>E. faecium</italic>. Vancomycin had a good antibacterial effect on the <italic>Enterococcus</italic> spp. isolates; however, resistance to this antibiotic and a high-level gentamicin resistance (HLGR) phenotype were observed. Among <italic>van</italic> operon genes, <italic>vanA</italic> was the most prevalent gene and among the gentamicin resistance genes, <italic>aph (3’)-IIIa</italic> was more frequent. The HLGR <italic>Enterococci</italic> are a real challenge in nosocomial infections. Vancomycin is a key antibiotic to treat such infections but emergence of VRE in our region could be a real concern and, therefore, phenotypic and molecular surveillance must be considered.</p></abstract>

Enterococcus faecalis and Enterococcus faecium are among the main agents associated with nosocomial infections with high mortality in immunocompromised patients. Antibiotic resistance, especially against gentamicin and vancomycin among Enterococci, is a risk factor that could increase the morbidity and mortality rate. 179 Enterococci isolates from burn patients were included in this study. Antibiotic susceptibility testing was done using the disk diffusion test and minimum inhibitory concentration (MIC) was evaluated by agar microdilution. Vancomycin and gentamicin resistance associated genes including vanA, vanB, vanC, aac (6’)-Ie aph(2’’), aph(3’)-IIIa and ant(4’)-Ia were detected by PCR and their statistical relation with antibiotic resistance was evaluated. E. faecalis was the more prevalent strain among our local isolates and showed a higher antibiotic resistance in comparison to E. faecium. Vancomycin had a good antibacterial effect on the Enterococcus spp. isolates; however, resistance to this antibiotic and a high-level gentamicin resistance (HLGR) phenotype were observed. Among van operon genes, vanA was the most prevalent gene and among the gentamicin resistance genes, aph (3’)-IIIa was more frequent. The HLGR Enterococci are a real challenge in nosocomial infections. Vancomycin is a key antibiotic to treat such infections but emergence of VRE in our region could be a real concern and, therefore, phenotypic and molecular surveillance must be considered.

Emergence of High-level Gentamicin Resistance among <italic>Enterococci</italic> Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Emergence of High-level Gentamicin Resistance among  Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Enterococcus faecalis and Enterococcus faecium are among the main agents associated with nosocomial infections with high mortality in immunocompromised...

Target gene	Oligonucleotide sequences (5’-3’)	Size of product (bp)	Reference
van A	GGGAAAACGACAATTGC GTACAATGCGGCCGTTA	732	Dutka-Malen et al. 1995
vanB	ATG GGA AGC CGA TAG TC GAT TTC GTT CCT CGA CC	638	Dutka-Malen et al. 1995
vanC	AAT CGT CAA TTC CTG CAT GT TAA TCG TGG AAT ACG GGT TTG	299	Dutka-Malen et al. 1995
aac(6’)-Ie aph(2’’)	AGGAATTTATCGAAAATGGTAGAAAAG CACAATCGACTAAAGAGTACCAATC	369	Vakulenko et al. 2003
aph(3’)-IIIa	GGCTAAAATGAGAATATCACCGG CTTTAAAAAATCATACAGCTCGCG	523	Vakulenko et al. 2003
ant(4’)-Ia	CAAACTGCTAAATCGGTAGAAGCC GGAAAGTTGACCAGACATTACGAACT	294	Vakulenko et al. 2003

Genus	van gene				Gentamicin gene
Genus	vanA	vanB	vanA, vanB	vanC	3’	4’	6’	3’ + 4’	3’ + 6’	4’ + 6’	3’ + 4’ + 6’
E. faecalis	14	3	3	1	74	8	67	3	26	6	4
E. faecium	9	0	3	2	48	10	42	6	50	2	1
Total (n)	23	3	6	3	122	18	109	9	76	8	5

Emergence of High-level Gentamicin Resistance among Enterococci Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Article Category: original-paper

Pubblicato online: 10 dic 2018

Pagine: 401 - 406

Ricevuto: 12 mar 2018

Accettato: 20 mag 2018

DOI: https://doi.org/10.21307/pjm-2018-043

Parole chiave
gentamicin, burn, vancomycin, drug resistance

© 2018 Maryam Labibzadeh et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1.

Primers used in this study.

Frequency of vancomycin and gentamicin resistance genes among our local Enterococci isolates.

The association between presence of gentamicin resistance genes and MICs against gentamicin.

Gene target		MIC (µg/ml)
		256		512		1024
		E. faecalis	E. faecium	E. faecalis	E. faecium	E. faecalis	E. faecium
Gentamicin resistance gene	aph(3’)-IIIa	0	0	3	1	2	3
	ant(4’)-Ia	0	0	3	1	0	0
	aac(6’)-Ie aph(2’’)	0	0	5	2	2	2

Emergence of High-level Gentamicin Resistance among Enterococci Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Article Category: original-paper

Pubblicato online: 10 dic 2018

Pagine: 401 - 406

Ricevuto: 12 mar 2018

Accettato: 20 mag 2018

DOI: https://doi.org/10.21307/pjm-2018-043

Parole chiavegentamicin, burn, vancomycin, drug resistance

© 2018 Maryam Labibzadeh et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Fig. 1.

Primers used in this study.

Frequency of vancomycin and gentamicin resistance genes among our local Enterococci isolates.

The association between presence of gentamicin resistance genes and MICs against gentamicin.

Parole chiave
gentamicin, burn, vancomycin, drug resistance