We examined the effect of drought-tolerant Bacillus safensis SS-2.7 and B. thuringiensis SS-29.2 strains on the response of four (133, 274, California Wonder—CalW, and Matica) sweet pepper genotypes ...to water deficiency conditions. Pepper seeds were sown in pots with (treated) and without (control) bacterial strain inoculation. After four weeks of growth under controlled conditions and regular watering, drought was imposed by completely withholding watering for seven days. Under conditions of normal watering, genotype 274 showed better seedling establishment than genotype 133 and CalW, while the slowest was genotype Matica. Antioxidant enzyme activity under drought conditions was genotype and bacterial treatment-dependent. The best response to bacterial treatment in order to cope with severe drought was found in the CalW genotype, while in genotype 133, we determined even faster plant decay during water deficiency in treated seeds. Inoculated seeds of the Matica genotype did not show different antioxidant enzyme activity under normal and drought conditions. According to the obtained results, we concluded that under drought conditions, the most susceptible was genotype 274, moderate susceptibility was detected in genotype 133, and CalW and Matica were the most tolerant genotypes. Our study demonstrates (1) that drought-tolerant Bacillus strains showed a plant growth-promoting effect on some selected pepper genotypes; (2) that there were genotype-dependent antioxidant enzyme activities under drought conditions in response to treatment with a particular bacterial strain; and (3) that we could expect a genotype-dependent response during biostimulant application, especially under stress conditions.
Drug resistance of
is a leading problem in hospital infections. The aim of this study was to determine the best molecular genetic discrimination method for
spp. isolates among 94 outpatients and ...inpatients and see their grouping by phenotype characteristics (biofilm formation, frequency of serotypes, pigmentation, production of different class of beta-lactamases, and susceptibility to different antibiotic classes) and genotype. The most common serotypes were P1, P6, and P11, while co-productions of pyoverdine and pyocyanin were observed in 70 % of isolates. A total of 77.66 % isolates were mostly weak and moderate biofilm producers. Isolates were susceptible to colistin (100 %), aztreonam (97.87 %), imipenem (91.49 %), doripenem (90.43 %), and meropenem (84.04 %). MICs values confirmed susceptibility to ceftazidime and cefepime and singled out meripenem as the most effective inhibitor. Most isolates were resistant to aminoglycosides and fluoroquinolones. Only two isolates produced ESBL, eight were carbapenemase producers, and five isolates produced MBLs. Twenty-nine isolates were multidrug-resistant; 82.8 % of which produced both pigments, 58.3 % were non-typeable, while the P6 and P11 serotypes were equally distributed (16.7 %). Thirteen MDR isolates were strong enzyme producers. RAPD PCR analysis using primer 272 proved the best at discriminatory fingerprinting for
isolates, as it allocated 12 clusters. A correlation between DNA patterns and antibiotic resistance, production of pigments, serotypes distribution, and biofilm formation was not observed, and only confirmed higher genetic heterogeneity among
isolates, which suggests that other molecular methods are needed to reveal potential relations between genotypic patterns and phenotypic characteristics.
Antibiotska rezistencija Pseudomonas aeruginosa vodeći je problem u bolničkim infekcijama. Cilj ovoga istraživanja bio je utvrditi najbolju diskriminatorno molekularno-genetičku metodu među 94 ...ambulantna i bolnička Pseudomonas spp. izolata kako bi se uvidjelo njihovo grupiranje u smislu različitih fenotipskih obilježja (stvaranje biofilma, učestalost serotipova, pigmentacija, proizvodnja različitih klasa beta-laktamaza i osjetljivost na različite skupine antibiotika) u skladu s genotipom. Najčešći serotipovi bili su P1, P6 i P11, a proizvodnja i pioverdina i piocijanina primijećena je kod 70 % izolata. Ukupno 77,66 % izolata uglavnom je iskazalo slabu i umjerenu proizvodnju biofilma. Izolati su bili osjetljivi na kolistin (100 %), aztreonam (97,87 %), imipenem (91,49 %), doripenem (90,43 %) i meropenem (84,04 %). Vrijednosti MIC-ova potvrdile su podložnost izolata ceftazidimu i cefepimu, a izdvojile su meropenem kao najučinkovitiji inhibitor. Većina izolata bila je otporna na aminoglikozid i fluorokinolon. Samo dva izolata proizvela su ESBL, osam izolata sintetiziralo je karbapenemaze, a pet izolata imalo je sposobnost proizvodnje MBL-a. Dvadeset devet izolata bilo je višestruko rezistentno na antibiotike, od kojih je 82,8 % proizvodilo oba pigmenta, 58,3 % bili su netipabilni, a serotipovi P6 i P11 bili su podjednako zastupljeni među njima (16,7 %). Trinaest MDR izolata bili su snažni proizvođači enzima. RAPD PCR analiza korištenjem 272 početnica pokazala se kao najbolja diskriminatorna metoda otiskom prsta (fingerprinting) za Pseudomonas izolate, izdvajajući čak 12 različitih klastera. U ovom istraživanju nije zabilježena povezanost između DNA obrazaca i otpornosti na antibiotike, proizvodnje pigmenata, distribucije serotipova i stvaranja biofilma, što potvrđuje puno veću genetičku heterogenost unutar samih izolata P. aeruginosa, pod čim se podrazumijeva uključivanje drugih molekularnih metoda u otkrivanju potencijalnih odnosa između genetičkih obrazaca i fenotipskih obilježja.
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