Evaluation of antimicrobial activity of the endophytic actinomycete R18(6) against multiresistant Gram-negative bacteria

Carvalho, Tiele; Van Der Sand, Sueli

doi:10.1590/0001-3765201620140655

Brasil

home Sumário navigate_before Anterior Atual Seguinte navigate_next

home Sumário

Biological Sciences • An. Acad. Bras. Ciênc. 88 (1) • Mar 2016 • https://doi.org/10.1590/0001-3765201620140655 linkcopy

Evaluation of antimicrobial activity of the endophytic actinomycete R18(6) against multiresistant Gram-negative bacteria

Authorship SCIMAGO INSTITUTIONS RANKINGS

Endophytic actinomycetes are promising sources of antimicrobial substances. This study evaluates the activity of metabolites produced by the endophytic actinomycete R18(6) against Gram-negative bacteria multiresistant to antimicrobials. R18(6) isolate was grown in submerged cultures under different conditions: carbon source, temperature, pH and incubation time to optimize antimicrobials production. The actinomycete grown in base medium supplemented with 1% glucose, pH 6.5 and incubation at 30 ºC for 96 h with shaking at 100 rpm, exhibited the highest activity against the used Gram-negative bacteria. Minimum inhibitory concentration (MIC) of the crude extract produced by the microorganism varied between 1/32 and 1/256. It had bactericide or bacteriostatic activity, depending on the Gram-negative organism. The active extract was stable at high temperatures, and unstable in medium containing proteolytic enzymes. Micromorphology of R18(6) was investigated by optical and scan microscopy, revealing that it was morphologically similar to the genusStreptomyces.

endophytic actinomycetes; Streptomyces; multiresistant Gram-negative bacteria; extract

Environmental isolates¹	Clinical isolates²
Citrobacter koseri 3CC04*	Citrobacter freundii 17*
Citrobacter koseri 3EC04	Enterobacter cloacae 49*
Citrobacter freundii 1CC09*	Enterobacter cloacae 62*
Pantoea agglomerans 3AE03	Escherichia coli 70*
Enterobacter intermedius 1CC07	Klebsiella oxytoca 90*
Escherichia coli 1DE14*	Klebsiella pneumonia 15*
Escherichia coli 4EC05	Klebsiella pneumoniae 222*
Klebsiella pneumonia 1CE02*	Morganella morganii 162*
Klebsiella oxytoca 2BS08	Proteus mirabilis 102*
Proteus mirabilis 3DC01*	Pseudomonas aeruginosa 54*
	Pseudomonas aeruginosa 59*
	Pseudomonas aeruginosa 230*

Gram-negative bacteria	Mean inhibition halos (mm)
Gram-negative bacteria	30 ºC	35 ºC
E. intermedius 1CC07	16.0	13.0
C. koseri 3CC04	17.0	12.0
K. oxytoca 90	17.5	13.0
E. coli 70	16.0	0.0
E. cloacae 62	16.0	0.0
M. morganii 162	14.5	0.0
P. aeruginosa 54	0.0	0.0
C. freundii 17	17.3	0.0
K. pneumoniae 222	19.2	14.0

Gram-negative bacteria	Incubation time / mean inhibition halos (mm)
Gram-negative bacteria	72 h^a,c	96 h^a	120 h^a,b	168 h^a,c
E. intermedius	1CC07	0.0	0.0	0.0	12.8
C. koseri	3CC04	12.3	13.5	0.0	14.5
K. oxytoca	90	12.8	14.0	13.3	0.0
E. coli	70	15.5	15.3	0.0	13.5
E. cloacae	62	12.3	14.5	13.3	13.5
M. morganii	162	13.8	13.5	0.0	0.0
P. aeruginosa	54	0.0	13.8	12.0	17.0
C. freundii	17	0.0	17.5	13.5	0.0
K. pneumoniae	222	15.8	21.0	15.0	16.5

Gram-negative bacteria	Metabolite extract concentration
Gram-negative bacteria	Extract	1/2	1/4	1/8	1/16	1/32	1/64	1/128	1/256	1/512	1/1024
Environmental Samples
K. pneumoniae 1CE02	Extract	1/2	1/4	1/8	1/16	1/32	1/64	1/128	1/256	1/512	1/1024	+	+	+	+	+	+	+	+	+	+	+
C. koseri 3CC04	+	+	+	+	+	+	+	+	+	+	+
E.coli 1DE14	+	+	+	+	+	+	+	+	+	+	+
C. freundii 1CC09	+	+	+	+	+	+	+	+	+	+	+
P. mirabilis 3DC01	+	+	+	+	+	+	+	+	+	+	+
Clinical Samples
K. pneumoniae 15	-	-	-	-	-	-	+	+	+	+	+
K. pneumoniae 222	+	+	+	+	+	+	+	+	+	+	+
K. oxytoca 90	+	+	+	+	+	+	+	+	+	+	+
E.coli 70	+	+	+	+	+	+	+	+	+	+	+
E. cloacae 62	+	+	+	+	+	+	+	+	+	+	+
E. cloacae 49	-	-	-	-	-	-	-	-	+	+	+
C. freundii 17	-	-	-	-	-	-	-	+	+	+	+
P. mirabilis 102	+	+	+	+	+	+	+	+	+	+	+
M. morganii 162	+	+	+	+	+	+	+	+	+	+	+
P. aeruginosa 54	+	+	+	+	+	+	+	+	+	+	+
P. aeruginosa 59	+	+	+	+	+	+	+	+	+	+	+
P. aeruginosa 230	+

vertical_align_top file_download show_chart

more_horizclose
- image
- translate
- link
- article
- vertical_align_top
- file_download
- show_chart
- image
- translate
- link
- article

location_on

Academia Brasileira de Ciências Rua Anfilófio de Carvalho, 29, 3º andar, 20030-060 Rio de Janeiro RJ Brasil, Tel: +55 21 3907-8100, CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit - Rio de Janeiro - RJ - Brazil
E-mail: aabc@abc.org.br

rss_feed Acompanhe os números deste periódico no seu leitor de RSS

Acessibilidade / Reportar erro

[TFN01] ¹Samples isolated from the waters of Diluvio stream, Porto Alegre, RS, Brazil (Oliveira et al. 2012).²Samples provided by Dr. Ana Lucia Souza Antunes, Laboratory of Analysis, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, RS, Brazil. *Isolates used in the MIC assay.