Pseudomonas Pseudoalcaligenes Research Articles

Paddy plants inoculated with PGPR show better growth physiology and nutrient content under saline conditions

The possible role of plant growth-promoting rhizobacteria (PGPR) to alleviate salt stress during plant growth has been studied on paddy rice ( Oryza sativa L.) 'GJ-17' under greenhouse conditions; the study included growth parameters, mineral concentration, and antioxidant enzyme level. Salinity reduced plant growth, but PGPR inoculation reduced its harmful effect up to 1% salinity. Plants inoculated with PGPR under saline conditions showed 16% higher germination, 8% higher survival, 27% higher dry weight, and 31% higher plant height. Similarly, PGPR inoculated plants showed increased concentrations of N(26%), P (16%), K (31%), and reduced concentrations of Na (71%) and Ca (36%) as compared to non-inoculated control plants under saline conditions. Plants inoculated with PGPR under saline conditions also showed significant variations in antioxidant levels and growth physiology. Results suggested that inoculation with PGPR Bacillus pumilus and Pseudomonas pseudoalcaligenes in salt-stressed plants could help to alleviate salt stress in the paddy.

Purification and characterization of protocatechuate 3,4-dioxygenase from Pseudomonas pseudoalcaligenes KF707

Protocatechuate 3,4-dioxygenase was isolated and characterized from Pseudomonas pseudoalcaligenes KF707 for the purpose of developing a new anti-browning agent. The protocatechuate 3,4-dioxygenase from Pseudomonas pseudoalcaligenes KF707 was purified 296.8-fold, and showed specific activity of 121.7 U/mg. Based on the SDS-polyacrylamide and gel permeation chromatography, the molecular weight of protocatechuate 3,4-dioxygenase was 189.9 kDa and was composed of 3 αβ protomers, with molecular weights of 29.0 kDa of α subunit and 34.3 kDa of â subunit. The optimal pH and temperature were 7.5 and 38°C, respectively. Km values of catechol, protocatechuate, gallate, p-cresol, caffeic acid, catechin, L-DOPA, 4-methylcatechol and pyrogallol were 14, 17, 2, 10, 12, 20, 30, 21 and 3 μM, and the Vmax/Km (mim−1) values were 0.052, 3.06, 0.35, 0.01, 0.03, 0.02, 0.006, 0.008 and 0.11, respectively. This indicates that the enzyme is active on a wide range of phenyl compounds, in contrast to the high specificity of similar enzymes from other sources. Our data also show that the turnover number of protocatechuate 3,4-dioxygenase from Pseudomonas pseudoalcaligenes KF707 is 68 s−1, which is much higher than the known values from other sources.

Characterization of root-associated bacteria from paddy and its growth-promotion efficacy.

Bacteria from rhizosphere (Bacillus pumilus) and endorhizophere (Pseudomonas pseudoalcaligenes) of rice plant were isolated and evaluated for their effect on the growth-promotion efficiency on rice in greenhouse. Ability to solubilize phosphate, siderophore, indoleacetic acid (IAA), gibberellin production and utilization of ACC (1-aminocyclopropane-1-carboxylate) as sole nitrogen source were evaluated, which were produced in high concentration by P. pseudoalcaligenes in this present study. Inoculation of isolated microorganism resulted in the reduction of pH (from neutral to acidic) of the medium used for phosphate solubilization, and has direct relation with titratable acidity, but gluconate production showed an opposite trend. P. pseudoalcaligenes better helped the plant to overcome or suppress fungal pathogen infection by producing β-1, 3-glucanase and chitinase as well as also have enhanced dry weight, plant height, and root length. Based on these results, P. pseudoalcaligenes in this study proved a better candidature as PGPR than B. pumilus.

Kinetics Approach of Biodegradation of Petroleum Contaminated Soil by using Indigenous Isolated Bacteria

The bioremediation of petroleum contaminated soil was investigated using a microscale Landfarming. The Indigenousbacteria, Pseudomonas pseudoalcaligenes, Bacillus megaterium, and Xanthobacter autotrophicus were isolated from the contaminated sites Sungai Lilin Jambi Pertamina Ltd and used further in the bioremediation experiments. The biodegradation rates of petroleum contaminated soil in the presence of the isolated bacteria were studied by using the chemical kinetics approach. The reaction orders were studied by using the differential method and the reaction rate constants were studied by using the integral method. The results showed that the reaction orders were 1.0949, 1.3985, 0.8823, and the reaction rate constants were 0.0189, 0.0204, 0.0324 day-1, respectively. Considering the values of reaction orders and reaction rate constants, the biodegradation rate of contaminated soil by usingeach bacteria had significantly different value; Xanthobacter Autotrophicus bacteria could degrade the petroleumoil sludge fastest than the others.Keywords: Biodegradation, indigenous bacteria, kinetics, petroleum oil

Metabolic and molecular methods to evaluate the organoclay effects on a bacterial community

The aim of this work was to evaluate the influence exerted by two different commercial organoclays (DELLITE 43B and DELLITE 67G) on a model microbial consortium using microbial metabolic characterization with BIOLOG system and denaturing gradient gel electrophoresis (DGGE) molecular approach. The information obtained from the molecular analyses, in their complex, account for the differences in species composition induced on the reference consortium by the contact with the organoclays under study. DELLITE 43B resulted to produce a marked selective effect, stimulating the quantitative increase especially of Pseudomonas pseudoalcaligenes. A weaker effect was found for DELLITE 67G. On the other hand, Biolog analyses indicated a depressing action exerted by DELLITE 43B on the metabolic activity of the model microbial consortium as a whole. The presence of P. pseudoalcaligenes and B. borstelensis in the bacterial community after the treatments confirmed that a positive change in the microbial structure consortium occurred.

English

The endophytic bacterial communities in tomato varieties having differing resistance (or susceptibility) to Ralstonia solanacearum were investigated using both cultivation dependent and independent approaches. Both approaches revealed the differences between resistant (Xiahong-1) and susceptible (Baoshi-5) cultivars in terms of diversity and abundance of endophytic bacteria. The amount of the endogenous bacteria in Xiahong-1 at different growth stages was significantly higher than that in Baoshi-5. Furthermore, there were more culturable and antagonistic endophytic bacteria in Xiahong-1 than that in Baoshi-5. Seven endophytic bacterial genetic groups were identified in Xiahong-1 by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) and 16S rDNA sequence, and they were highly similar to Sphingomonas yanoikuya, Pseudomonas pseudoalcaligenes, Serratia marcescens, Bacillus megaterium, Paenibacillus polymyxa, B. pumilus and B. cereus. Four groups were identified in Baoshi-1 which were highly similar to S. yanoikuyae, Pseudomonasfluorescens, Arthrobacter globiformis and Paenibacillus polymyxa. In addition, antagonistic endophytes were identified by 16S rRNA gene analysis, and tested for their abilities to protect tomato plants from infection with R. solanacearum. The relationships between plant resistance and endophytic bacteria diversity are discussed. Key words: Tomato, Ralstonia solanacearum, resistance, endophytic bacteria, diversity,biological control, 16S rRNA gene.

Application of the Surface Complexation Model to the Biosorption of Cu(II) and Pb(II) Ions onto Pseudomonas Pseudoalcaligenes Biomass

In this study, a potentiometric titration was performed to investigate the surface acid-base properties of Pseudomonas pseudoalcaligenes isolated from activated sludge. Batch sorption as a function of pH was performed to explain the sorption behaviour of Cu(II) and Pb(II) ions onto the bacterial surface. The surface complexation approach in the frame of constant capacitance model was applied to determine the deprotonation constants, site concentrations and metal stability constants for the important surface-functional groups on the biomass. The optimized results showed that the three discrete sites-three pK(a)s model, involving three distinct types of functional groups, namely, carboxyl, phosphate and hydroxyl, could actually fit the protonation of the bacterial functional groups, with average pK(a) values of 4.18, 6.31 and 9.18, and site concentrations of 0.526, 0.525 and 0.478 mmol/g, respectively. The two sites model provided the best fit for the biosorption of Cu(II) and Pb(II) ions onto the biomass by forming complexes with carboxyl and phosphate surface sites, with average log stability constants of 5.95 and 6.94 for Cu(II), and 6.64 and 8.08 for Pb(II), respectively. These results suggested that the surface complexation model yielded the accurate prediction for the biosorption behaviour of Cu(II) and Pb(II) ions on the bacterial biomass and the affinity of P. pseudoalcaligenes biomass for the adsorption of Cu(II) and Pb(II) ions was high enough to remove the metal ions from water.

Study for anti-infective potential of antibacterial properties of Murraya Koenigii

In vitro antimicrobial efficacy of leaves extracts of Murraya koenigii was performed by disc diffusion method against six Gram positive bacterial (Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus subfava), nine Gram negative bacterial (Alcaligenes fecalis, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas pseudoalcaligenes and Salmonella typhimurium) and two fungal strains (Aspergillus brasiliensis, candida albicans). The most susceptible bacterial strains were Bacillus subtilis and Staphylococcus aureus whereas not showing antifungal activity. The leaf extracts in organic solvents (methanol) showed better antimicrobial activity as compared to aqueous extracts Results of present study shows that leaves of Murraya koenigii having antimicrobial activity and can be used for natural antimicrobial agent.

The Three-Species Consortium of Genetically Improved Strains Cupriavidus necator RW112, Burkholderia xenovorans RW118, and Pseudomonas pseudoalcaligenes RW120 Grows with Technical Polychlorobiphenyl, Aroclor 1242

Burkholderia xenovorans LB400, Cupriavidus necator H850, and Pseudomonas pseudoalcaligenes KF707 are bacterial strains able to mineralize biphenyl and to co-oxidize many of its halogenated derivatives (PCBs). Only strain LB400 also mineralizes a few mono- and dichlorobiphenyls, due to the presence of a functioning chlorocatechol pathway. Here, we used a Tn5-based minitransposon shuttle system to chromosomically introduce genes tcbRCDEF, encoding the chlorocatechol pathway into KF707, and genes cbdABC encoding a 2-chlorobenzoate 1,2-dioxygenase into KF707 and LB400, as well as transposon Tn4653 from the TOL plasmid, providing genes xylXYZL, encoding a broad-range toluate (methylbenzoate) dioxygenase and its dihydrodiol dehydrogenase, to extend the range for the mineralization of halogenated benzoates in LB400 and in KF707 through co-oxidation of halobenzoates into chlorocatechols. The engineered derivatives of LB400 and KF707 thus gained the ability for the mineralization of all isomeric monochloro- and bromobenzoates of the so-called lower pathway which, consequently, also allowed the mineralization of all monochlorobiphenyls and a number of di- and trichlorobiphenyls, thus preventing the accumulation of halobenzoates and of catabolites thereof. LB400 and KF707 also grow with the two commercial PCB formulations, Aroclor 1221 and Aroclor 1232, as the sole carbon and energy sources, but not with higher halogenated PCB mixtures, similar to the already published strain RW112. Repeated exposition of the modified LB400 to short pulses of UV light, over a prolonged period of time, allowed the isolation of a derivative of LB400, termed RW118, capable of growth with Aroclor 1016 still containing only traces of biphenyl, and in co-culture with modified KF707 termed RW120, and modified H850 (RW112) with Aroclor 1242, the commercial mixture already void of biphenyl and monochlorobiphenyls.

Effect of aluminium and copper on biofilm development of Pseudomonas pseudoalcaligenes KF707 and P. fluorescens as a function of different media compositions

Bioremediation efforts worldwide are faced with the problem of metals interfering with the degradation of organic pollutants. There has been little systematic investigation into how the important environmental factors of media composition, buffering agent, and carbon source affect the exertion of metal toxicity on bacteria. This study aimed to systematically separate and investigate the influence of these factors by examining planktonic and biofilm establishment and growth. Two Pseudomonads were chosen, the PCB degrader P. pseudoalcaligenes KF707 and P. fluorescens. The two strains were grown in the presence of Al(3+) and Cu(2+) under different media conditions of carbon source (Lysogeny broth, biphenyl, succinate, aspartic acid, butyric acid, oxaloacetic acid, putrescine and benzoic acid) and under different buffering conditions (high and low phosphate or MOPS). These experiments allowed for the elucidation of an effect of different metabolic conditions and metal speciation on planktonic bacteria growth and biofilm establishment and development under metal stress. Here we show that the nature of bacterial growth (planktonic and biofilm development) is dramatically affected by the interplay between toxic metals, carbon source and media composition. The capacity of a media to bind toxic metals as well as quality of carbon source greatly influences the amount of metal that bacteria can tolerate, depending on both the bacterium and metal. Future studies evaluating metal ion toxicity should consider these effects, as well as their interactions with specific environments into account in order to improve clean-up success.

Crystallization and preliminary X-ray diffraction analysis of the organophosphorus hydrolase OPHC2 from Pseudomonas pseudoalcaligenes.

Enzymes that are capable of degrading neurotoxic organophosphorus compounds are of increasing interest because of the lack of efficient and clean methods for their removal. Recently, a novel organophosphorus hydrolase belonging to the metallo-β-lactamase superfamily was identified and isolated from the mesophilic bacterium Pseudomonas pseudoalcaligenes. This enzyme, named OPHC2, is endowed with significant thermal and pH stability, making it an appealing candidate for engineering studies to develop an efficient organophosphorus biodecontaminant. Combined with biochemical studies, structural information will help decipher the catalytic mechanism of organophosphorus hydrolysis by OPHC2 and identify the residues involved in its substrate specificity. Here, the expression, purification, crystallization and X-ray data collection at 2.1 Å resolution of OPHC2 are presented.

Influence of soil ameliorants and microflora on induction of antioxidant enzymes and growth promotion of Jatropha curcas L. under saline condition

This study investigated the influence of inoculation with plant growth promoting rhizobacterium, Enterobacter clocae (MSA), Pseudomonas pseudoalcaligenes (MSC) and Bacillus sp., with a mycorrhizal fungus, Glomus intraradices, on seed germination parameters, vegetative growth, mineral nutrient uptake in leaves of Jatropha curcas L., soil nutrient management, antioxidant enzyme activities, phosphatase activity, solute accumulation under 2% salinity stress. Inoculation with plant growth promoting rhizobacteria (PGPR) increases the number of roots, root length, fresh weight of root and dry weight of root, number of leaves, and chlorophyll content. Addition of mycorrhizal inoculation was the next most effective in growth promotion of Jatropha. Inoculation of vermicompost increases shoot width as compared to other treatments. Soil analysis showed increase in C, N, and P in plants inoculated with PGPR strain. Further plant analysis showed that PGPR could increase uptake of N, P, K and Na. However, mycorrhizal fungus was observed to increase sulphur uptake while, vermicompost increase uptake of iron and copper. Treatment with vermicompost and PGPR showed an increase in acid and alkaline phosphatase. Salt stress increased proline concentration, particularly in plants inoculated with PGPR. Increased salinity stress raised significantly the antioxidant enzyme activities, including those of ascorbate peroxidase and catalase of Jatropha leaves. The PGPR strain induced a higher increase in these antioxidant enzymes in response to salinity. Inoculation with selected PGPR could serve as a useful tool for alleviating salinity stress in Jatropha.

Assessment of rhizobacteria from grapevine for their suppressive effect on the parasitic nematode Xiphinema index

The capacity of rhizobacteria isolated from grape plants to protect grapevine roots from damage by the nematode Xiphinema index was assessed in trials carried out in the growing season 2008–2009 and 2009–2010. A total of two groups of bacteria were evaluated, one comprising 49 isolates, of which 37 were assessed in previous studies, and one comprising 90 isolates not previously evaluated. Two assays were performed on the first group, one per season, and one on the second group, lasting two growing seasons. Pots of field soil (3 L) planted with two-month old Thompson Seedless vines were inoculated with 200 or 400 specimens of X. index after inoculation with 106 cfu/ml of test rhizobacteria; the posts were maintained in a shaded greenhouse. Seven isolates from the first group of bacteria (Bacillus brevis, Bacillus megaterium, Cytophaga johnsonae, Pseudomonas fluorescens, Rahnella aquatilis and Stenotrophomonas maltophilia) were effective in decreasing damage in both of the assays (P < 0.05). Ten isolates from the second group (Variovorax paradoxus, Pseudomonas pseudoalcaligenes, Bacillus mycoides, Bacillus sphaericus, Bacillus thuringiensis, Curtobacterium flaccumfaciens, Pseudomonas putida, Pseudomonas alcaligenes and Pseudomonas viridiflava) resulted in the lowest number of galls per gram root. B. brevis and B. megaterium also demonstrated good activity in previous studies on grape plants and are thus promising candidates for further research.

Draft whole genome sequence of the cyanide‐degrading bacteriumPseudomonas pseudoalcaligenesCECT5344

Pseudomonas pseudoalcaligenes CECT5344 is a Gram-negative bacterium able to tolerate cyanide and to use it as the sole nitrogen source. We report here the first draft of the whole genome sequence of a P. pseudoalcaligenes strain that assimilates cyanide. Three aspects are specially emphasized in this manuscript. First, some generalities of the genome are shown and discussed in the context of other Pseudomonadaceae genomes, including genome size, G + C content, core genome and singletons among other features. Second, the genome is analysed in the context of cyanide metabolism, describing genes probably involved in cyanide assimilation, like those encoding nitrilases, and genes related to cyanide resistance, like the cio genes encoding the cyanide insensitive oxidases. Finally, the presence of genes probably involved in other processes with a great biotechnological potential like production of bioplastics and biodegradation of pollutants also is discussed.

Tributyl phosphate degradation in batch and continuous processes using Pseudomonas pseudoalcaligenes MHF ENV

Tributyl phosphate (TBP) degradation was carried out in a batch process using free and immobilized cells of Pseudomonas pseudoalcaligenes MHF ENV and the effect of immobilization on TBP degradation and cell growth was investigated. Immobilization was found to enhance the rate and onset of TBP degradation. The initial degradation rate for immobilized cells was 2.8 times higher than for free cells and was attributed to the enhanced growth rate of the immobilized cells. Continuous TBP degradation was then carried out in a packed bed reactor using agarose immobilized cells of P. pseudoalcaligenes MHF ENV and the effect of flow rate on TBP degradation was studied. With 75 mg l−1 TBP as feed, degradation efficiency of 100, 96 and 47% and degradation rates of 75, 100.8 and 70.5 mg l−1 h−1 were achieved at the flow rate of 15, 21 and 30 ml h−1 respectively. Although the flow rate of 15 ml h−1 could achieve total degradation of TBP, flow rate of 21 ml h−1 was found to achieve maximum TBP degradation rate. This is the first study on continuous degradation of TBP, using a stable bacterial pure culture where TBP served as the sole source of carbon.

The nit1C gene cluster of Pseudomonas pseudoalcaligenes CECT5344 involved in assimilation of nitriles is essential for growth on cyanide

A proteomic approach was used to identify several proteins induced by cyanide in the alkaliphilic bacterium Pseudomonas pseudoalcaligenes CECT5344, two of them, NitB and NitG, encoded by genes that belong to the nit1C gene cluster. The predicted products of the nit1C gene cluster are a Fis-like σ(54) -dependent transcriptional activator (NitA), a nitrilase (NitC), an S-adenosylmethionine superfamily member (NitD), an N-acyltransferase superfamily member (NitE), a trifunctional polypeptide of the AIRS/GARS family (NitF), an NADH-dependent oxidoreductase (NitH) and two hypothetical proteins of unknown function (NitB and NitG). RT-PCR analysis suggested that nitBCDEFGH genes were co-transcribed, whereas the regulatory nitA gene was divergently transcribed. Real-time RT-PCR revealed that expression of the nitBCDEFGH genes was induced by cyanide and repressed by ammonium. The P. pseudoalcaligenes CECT5344 nit1C gene cluster was found to be involved in assimilation of free and organic cyanides (nitriles) as deduced for the inability to grow with cyanides showed by the NitA, NitB and NitC mutant strains. The wild-type strain CECT5344 showed a nitrilase activity that allows growth on cyanide or hydroxynitriles. The NitB and NitC mutants only presented low basal levels of nitrilase activity that were not enough to support growth on either free cyanide or aliphatic nitriles, suggesting that nitrilase NitC is specific and essential for cyanide and aliphatic nitriles assimilation.

Beta-lactams resistance and presence of class 1 integron in Pseudomonas spp. isolated from untreated hospital effluents in Brazil

The aim of the present study was to investigate the resistance profile, to detect the presence of beta-lactam resistance genes, phenotypic expression of efflux pump systems and class 1 integrons in Pseudomonas spp. strains obtained from untreated hospital effluents. Effluent samples were collected from four hospitals in Porto Alegre, RS, Brazil. Pseudomonas were isolated on MacConkey agar plates and the identification was confirmed by 16S rRNA PCR and biochemical tests. Susceptibility testing was determined by disk-diffusion method using 11 different beta-lactams and MIC assays were performed on isolates resistant to imipenem and ceftazidime. The beta-lactamase genes bla (IMP), bla (VIM), bla (SPM-1), bla (OXA-23-like), bla (OXA-24-like), bla (OXA-51-like) and the intl1 gene from class 1 integron were analysed by PCR. One hundred and twenty-four isolates were recovered and the most common species was Pseudomonas pseudoalcaligenes. The resistance found among the isolates was considered high, 62 (50%) isolates were multiresistant. No isolate carrying the beta-lactamase genes tested was found among the strains. Seven isolates showed reduction of MIC for imipenem and ceftazidime in the presence of cyanide m-chlorophenylhydrazone, indicating the hyper expression of efflux pumps. From the 124 isolates, 52 (41.9%) were identified as carrying the class 1 integron gene, intI1. Untreated hospital effluents could be a source of environmental contamination due to discharge of antimicrobial resistant bacteria which can carry integron class 1 and act as a reservoir of resistance genes and have efflux pump systems.

Root Associated Bacteria from the Rice antagonizes the Growth of Magnaporthe grisea

Root associated bacteria were isolated from the rice field by using nitrogen free selective medium. The biochemical tests and molecular analysis were preformed for the identification of isolates. Then the sequences obtained were analyzed by using bioinformatics software and the cultures were identified as Pseudomonas pseudoalcaligenes, Bacillus pumilus and Stenotrophomonas maltophilia. Then these isolates were in vitro inoculated to paddy plant to study their effect on plant growth promotion and resistance against pathogen. Results obtained during greenhouse showed antagonistic effect of these isolates against Magnaporthe grisea and enhance growth parameters.

Impact of an indigenous microbial enhanced oil recovery field trial on microbial community structure in a high pour-point oil reservoir

Based on preliminary investigation of microbial populations in a high pour-point oil reservoir, an indigenous microbial enhanced oil recovery (MEOR) field trial was carried out. The purpose of the study is to reveal the impact of the indigenous MEOR process on microbial community structure in the oil reservoir using 16Sr DNA clone library technique. The detailed monitoring results showed significant response of microbial communities during the field trial and large discrepancies of stimulated microorganisms in the laboratory and in the natural oil reservoir. More specifically, after nutrients injection, the original dominant populations of Petrobacter and Alishewanella in the production wells almost disappeared. The expected desirable population of Pseudomonas aeruginosa, determined by enrichment experiments in laboratory, was stimulated successfully in two wells of the five monitored wells. Unexpectedly, another potential population of Pseudomonas pseudoalcaligenes which were not detected in the enrichment culture in laboratory was stimulated in the other three monitored production wells. In this study, monitoring of microbial community displayed a comprehensive alteration of microbial populations during the field trial to remedy the deficiency of culture-dependent monitoring methods. The results would help to develop and apply more MEOR processes.

Spoilage potentials and antimicrobial resistance of Pseudomonas spp. isolated from cheeses

Pseudomonas spp. are aerobic, gram-negative bacteria that are recognized as major food spoilage microorganisms. A total of 32 (22.9%) Pseudomonas spp. from 140 homemade white cheese samples collected from the open-air public bazaar were isolated and characterized. The aim of the present study was to investigate the biochemical characteristics, the production of extracellular enzymes, slime and β-lactamase, and antimicrobial susceptibility of Pseudomonas spp. isolated from cheeses. The identified isolates including Pseudomonas pseudoalcaligenes, Pseudomonas alcaligenes, Pseudomonas aeruginosa, Pseudomonas fluorescens biovar V, and P. pseudoalcaligenes ssp. citrulli were found to produce extracellular enzymes, respectively: protease and lecithinase production (100%), and lipase activity (85.7, 42.9, 100, and 100%, and nonlipolytic, respectively). The isolates did not produce slime and had no detectable β-lactamase activity. The antimicrobial susceptibility of the isolates was tested using the disk diffusion method. Pseudomonas spp. had the highest resistance to penicillin G (100%), then sulphamethoxazole/trimethoprim (28.1%). However, all Pseudomonas spp. isolates were 100% susceptible to ceftazidime, ciprofloxacin, amikacin, gentamicin, and imipenem. Multidrug-resistance patterns were not observed among these isolates. In this study, Pseudomonas spp., exhibiting spoilage features, were isolated mainly from cheeses. Isolation of this organism from processed milk highlights the need to improve the hygienic practices. All of the stages in the milk processing chain during manufacturing have to be under control to achieve the quality and safety of dairy products.