Search

In the era of ubiquitous computing, the challenges imposed by the increasing demand for real-time data processing, security, and energy efficiency call for innovative solutions. The emergence of fog computing has provided a promising paradigm to address these challenges by bringing computational resources closer to data sources. Despite its advantages, the fog computing characteristics pose challenges in heterogeneous environments in terms of resource allocation and management, provisioning, security, and connectivity, among others. This paper introduces COGNIFOG, a novel cognitive fog framework currently under development, which was designed to leverage intelligent, decentralized decision-making processes, machine learning algorithms, and distributed computing principles to enable the autonomous operation, adaptability, and scalability across the IoT-edge-cloud continuum. By integrating cognitive capabilities, COGNIFOG is expected to increase the efficiency and reliability of next-generation computing environments, potentially providing a seamless bridge between the physical and digital worlds. Preliminary experimental results with a limited set of connectivity-related COGNIFOG building blocks show promising improvements in network resource utilization in a real-world-based IoT scenario. Overall, this work paves the way for further developments on the framework, which are aimed at making it more intelligent, resilient, and aligned with the ever-evolving demands of next-generation computing environments.

Enterobacterales resistant to extended-spectrum cephalosporins (ESC) are a marker of the antimicrobial resistance (AMR) burden. They are infecting humans, but the intestinal microbiota can also be transiently colonized without developing symptoms. Healthy carriage can promote silent dissemination of resistant bacteria, and data on this colonization are often lacking. Between 2021 and 2023, a sampling of healthy Tunisian people was carried out. Fecal samples (n = 256) were plated on selective agar, and all collected isolates were characterized by phenotypic (antibiograms) and genomic (whole-genome sequencing) methods. A total of 26 (26/256, 10.2%) isolates were collected, including 24 Escherichia coli and 2 Klebsiella pneumoniae . In total, 17 isolates (15 E. coli and 2 K. pneumoniae ) presented an ESBL phenotype conferred by the bla CTX-M-15 gene, and 9 E. coli isolates presented an AmpC phenotype conferred by the bla DHA-1 gene. K. pneumoniae belonged to ST1564 and ST313, while E. coli belonged to diverse STs including the pandemic ST131 clone. Clonally related ST349 E. coli isolates carrying the bla DHA-1 gene were found in nine individuals. In parallel, four bla CTX-M-15 -positive E. coli isolates carried this ESC-resistance gene on an epidemic plasmid IncF/F-:A-:B53 previously identified in Tunisian pigeons and fish. These findings highlight the spread of genetically diverse ESC-resistant Enterobacterales as well as an epidemic plasmid in Tunisia, emphasizing the need for antimicrobial stewardship to limit the transmission of these resistances in the Tunisian population.

The One Health approach of antimicrobial resistance highlighted the role of the aquatic environment as a reservoir and dissemination source of resistance genes and resistant bacteria, especially due to anthropogenic activities. Resistance to extended-spectrum cephalosporins (ESC) conferred by extended-spectrum beta-lactamases (ESBLs) in E. coli has been proposed as the major marker of the AMR burden in cross-sectoral approaches. In this study, we investigated wastewater, surface water and seawater that are subjected to official water quality monitoring in Monastir, Tunisia. While all but one sample were declared compliant according to the official tests, ESC-resistant bacteria were detected in 31 (19.1 %) samples. Thirty-nine isolates, coming from urban, industrial and surface water in Monastir, were collected and characterized using antibiograms and whole-genome sequencing. These isolates were identified as 27 Escherichia coli (69.3 %) belonging to 13 STs, 10 Klebsiella pneumoniae (25.6 %) belonging to six STs, and two Citrobacter freundii (5.1 %). We observed the persistence and dissemination of clones over time and in different sampling sites, and no typically human-associated pathogens could be identified apart from one ST131. All isolates presented a bla CTX-M gene - bla CTX-M-15 (n = 22) and bla CTX-M-55 (n = 8) being the most frequent variants - which were identified on plasmids (n = 20) or on the chromosome (n = 19). In conclusion, we observed ESC resistance in rather ubiquitous bacteria that are capable of surviving in the water environment. This suggests that including the total coliform count and the ESBL count as determined by bacterial growth on selective plates in the official monitoring would greatly improve water quality control in Tunisia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: Wild birds are vectors of antimicrobial resistance. Birds living in close contact with humans or other animals, like feral pigeons (Columba livia), might be especially prone to acquire resistance genes such as those encoding extended-spectrum beta-lactamases (ESBLs) and carbapenemases., Methods: Cloacal samples (n = 206) of free-living feral pigeons (C. livia) were collected in Sousse and Monastir, Tunisia. Antimicrobial susceptibility profiles were determined by disc-diffusion, and resistant isolates were short- and long-read whole-genome sequenced. Sequence analysis was performed using tools of the Centre for Genomic Epidemiology, and Phylogenetic analysis was performed based on the core-genome MLST., Results: Fourteen (14/206, 6.8%) pigeons harboured Enterobacterales resistant to last-generations cephalosporins, of which 10 were CTX-M-15- or CTX-M-27-producers, while two (1.0%) carried a VIM-2-producing Pseudomonas putida. Positive pigeons lived on four different livestock farms. Three STs (ST206, ST5584, ST8149) were identified among E. coli, of which ST5584 and ST8149 were found in two different farms. Genetic diversity was also observed in Enterobacter cloacae and P. putida isolates. The bla CTX-M-27 genes were chromosomally encoded, while the bla CTX-M-15 genes were carried on highly similar IncF/F-:A-:B53 plasmids. The bla VIM-2 gene was located on a class 1 integron co-harbouring several resistance genes., Conclusion: Pigeons living on livestock farms carried clinically important resistance genes encoding ESBLs and carbapenemases. Our results evidenced that both clonal (ST8149 and ST5584) and plasmidic (IncF/F-:A-:B53) transfers played a role in the spread of resistance genes among pigeons. Further studies are needed to identify factors favouring the transfer and persistence of resistance genes within the pigeon communities., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: In Tunisia, the prevalence of diabetes mellitus increased from 15.5% on 2016 to 23% by 2023. While Chronic Kidney Disease (CKD) stills the most dreaded complications of diabetes, studies on the prevalence of chronic kidney disease non-dialysis diet are scarce. The aim of this study was to assess the prevalence of chronic kidney disease among the Tunisian diabetic population based on investigators' specialty, demographic criteria (gender, age, duration of diabetes and geographic distribution) and diagnosis criteria (albuminuria and/or eGFR)., Methods: This observational, multicentric, and cross-sectional study enrolled all diabetic subjects from all regions of Tunisia with at least 3 months of follow-up before the inclusion date, from 09 January to 08 February 2023. CKD diagnosis was established based on the KDIGO guidelines. The study was carried out at medical departments and ambulatory clinics of different healthcare providers. Baseline data were collected by investigators using an electronic case report form (eCRF). Continuous variables were described by means, median, standard deviation, and quartiles. Categorical data were tabulated in frequencies and percentages., Results: The overall prevalence of CKD among the 10,145 enrolled patients with diabetes mellitus was 38.7% with a 95%CI [37.8-39.6%]. 50.9% were male, with a mean age of 67.5 (± 11.3) years. The mean diabetes duration was 16.1 years (± 8.9). The highest CKD prevalence was noted among nephrologists (82.2%), while it was similar between the cardiologists and the primary care physicians (30.0%). CKD prevalence was highest among males (43.0% versus 35.1%) and increased proportionally with patients' age and diabetes duration. CKD was more frequent in the Mid-East Area when compared to other regions (49.9% versus 25.3 to 40.1% in other regions). Albuminuria was present within 6.6% of subjects with CKD, and it was found an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m² within 13.3% of subjects wit h CKD. 18.9% had both criteria., Conclusions: In Tunisia, CKD among diabetics had a prevalence of 38.7%, approaching European prevalence. The prevalence discrepancy worldwide of CKD can be improved with a larger population size and by implementing standardized practices., (© 2024. The Author(s).)

Carbapenem-resistant Acinetobacter baumannii (CRAB) strains can cause severe and difficult-to-treat infections in patients with compromised general health. CRAB strains disseminate rapidly in nosocomial settings by patient-to-patient contact, through medical devices and inanimate reservoirs. The occurrence of CRAB in patients residing in the intensive care units (ICUs) of the Sahloul University hospital in Sousse, Tunisia is high. The objective of the current study was to determine whether the surfaces of items present in five ICU wards and the medical personnel there operating could serve as reservoirs for CRAB strains. Furthermore, CRAB isolates from patients residing in the ICUs during the sampling campaign were analyzed for genome comparison with isolates from the ICUs environment. Overall, 206 items were screened for CRAB presence and 27 (14%) were contaminated with a CRAB isolate. The items were located in several areas of three ICUs. Eight of the 54 (15%) screened people working in the wards were colonized by CRAB on the hands. Patients residing in the ICUs were infected with CRAB strains sharing extensive genomic similarity with strains recovered in the nosocomial environment. The strains belonged to three sub-clades of the internationally disseminated clone (ST2). A clone emerging in the Mediterranean basin (ST85) was detected as well. The strains were OXA-23 or NDM-1 producers and were also pan-aminoglycoside resistant due to the presence of the armA gene. Hygiene measures are urgent to be implemented in the Sahloul hospital to avoid further spread of difficult-to-treat CRAB strains and preserve health of patients and personnel operating in the ICU wards.

European starlings are widespread migratory birds that have already been described as carrying bacteria resistant to extended-spectrum cephalosporins (ESC-R). These birds are well known in Tunisia because they spend the wintertime in this country and are hunted for human consumption. The goal of our study was to estimate the proportion of ESC-R in these birds and to characterize the collected isolates using whole-genome sequencing. Results showed that 21.5% (42/200) of the birds carried either an extended-spectrum beta-lactamase (ESBL) or an acquired AmpC gene. Diverse bla CTX-M genes were responsible for the ESBL phenotype, bla CTX-M-14 being the most prevalent, while only bla CMY-2 and one bla CMY-62 were found in AmpC-positive isolates. Likewise, different genetic determinants carried these resistance genes, including IncHI2, and IncF plasmids for bla CTX-M genes and IncI1 plasmids for bla CMY-2 genes. Three chromosomally encoded bla CTX-M-15 genes were also identified. Surprisingly, species identification revealed a large proportion (32.7%) of Escherichia marmotae isolates. This species is phenotypically indistinguishable from Escherichia coli and has obviously the same capacity to acquire ESC-R genes. Our data also strongly suggest that at least the IncHI2/pST3 plasmid can spread equally between E. coli and E. marmotae . Given the potential transmission routes between humans and animals, either by direct contact with dejections or through meat preparation, it is important to closely monitor antimicrobial resistance in European starlings in Tunisia and to set up further studies to identify the sources of contamination of these birds. IMPORTANCE The One Health concept highlighted knowledge gaps in the understanding of the transmission routes of resistant bacteria. A major interest was shown in wild migratory birds since they might spread resistant bacteria over long distances. Our study brings further evidence that wild birds, even though they are not directly submitted to antibiotic treatments, can be heavily contaminated by resistant bacteria. Our results identified numerous combinations of resistance genes, genetic supports, and bacterial clones that can spread vertically or horizontally and maintain a high level of resistance in the bird population. Some of these determinants are widespread in humans or animals (IncHI2/pST3 plasmids and pandemic clones), while some others are less frequent (atypical IncI1 plasmid and minor clones). Consequently, it is essential to be aware of the risks of transmission and to take all necessary measures to prevent the proportions of resistant isolates from increasing uncontrollably.

Resistance to extended-spectrum cephalosporins (ESC) and carbapenems in Enterobacterales is a major issue in public health. Carbapenem resistance in particular is associated with increased morbidity and mortality. Moreover, such resistance is often co-harbored with resistance to non-beta-lactam antibiotics, and pathogens quickly become multi-drug-resistant (MDR). Only a few studies have been published on AMR in Libyan hospitals, but all reported worrisome results. Here, we studied 54 MDR isolates that were collected from 49 patients at the Tripoli University Hospital between 2019 and 2021. They were characterized using phenotypic methods, PCR and PFGE, and a sub-set of isolates were short- and long-read whole-genome sequenced. The results showed the frequent occurrence of Klebsiella pneumoniae (49/54), among which several high-risk clones were responsible for the spread of resistance, namely, ST11, ST17, ST101 and ST147. ESC and carbapenem resistance was due to a wide variety of enzymes (CTX-M, OXA-48, NDM, KPC), with their corresponding genes carried by different plasmids, including IncF-IncHI2 and IncF-IncR hybrids. This study highlights that implementation of infection prevention, control and surveillance measures are needed in Libya to fight against AMR.

The gut microbiota is currently recognized as an important factor influencing the host's metabolism, immune, and central nervous systems. Determination of the composition of the gut microbiota of healthy subjects is therefore necessary to establish a baseline for the detection of alterations in the microbiota under pathological conditions. So far, most studies describing the gut microbiota have been performed in populations from Asia, North America, and Europe, whereas populations from Africa have been overlooked. Here, we present the first characterization of the intestinal microbiota in healthy Tunisian adults using 16S rRNA gene sequencing. We further compare the gut microbiota composition based on gender and BMI. Our results showed that the Tunisian gut microbiota is dominated by the phyla Firmicutes and Bacteroidota in accordance with studies from western countries. However, some specificities have been identified, including a higher proportion of Firmicutes in males and higher proportions of Atopobiaceae and Peptostreptococcaceae in Tunisian overweight individuals. Moreover, we were able to identify bacterial species differently represented between males and females and between normal weight and overweight individuals. These results constitute an important baseline that can be used to identify the dysbiosis associated with the main diseases affecting the Tunisian population., (© The Author(s) 2023. Published by Oxford University Press on behalf of FEMS.)

Background: The frequency of heart failure (HF) in Tunisia is on the rise and has now become a public health concern. This is mainly due to an aging Tunisian population (Tunisia has one of the oldest populations in Africa as well as the highest life expectancy in the continent) and an increase in coronary artery disease and hypertension. However, no extensive data are available on demographic characteristics, prognosis, and quality of care of patients with HF in Tunisia (nor in North Africa)., Objective: The aim of this study was to analyze, follow, and evaluate patients with HF in a large nation-wide multicenter trial., Methods: A total of 1700 patients with HF diagnosed by the investigator will be included in the National Tunisian Registry of Heart Failure study (NATURE-HF). Patients must visit the cardiology clinic 1, 3, and 12 months after study inclusion. This follow-up is provided by the investigator. All data are collected via the DACIMA Clinical Suite web interface., Results: At the end of the study, we will note the occurrence of cardiovascular death (sudden death, coronary artery disease, refractory HF, stroke), death from any cause (cardiovascular and noncardiovascular), and the occurrence of a rehospitalization episode for an HF relapse during the follow-up period. Based on these data, we will evaluate the demographic characteristics of the study patients, the characteristics of pathological antecedents, and symptomatic and clinical features of HF. In addition, we will report the paraclinical examination findings such as the laboratory standard parameters and brain natriuretic peptides, electrocardiogram or 24-hour Holter monitoring, echocardiography, and coronarography. We will also provide a description of the therapeutic environment and therapeutic changes that occur during the 1-year follow-up of patients, adverse events following medical treatment and intervention during the 3- and 12-month follow-up, the evaluation of left ventricular ejection fraction during the 3- and 12-month follow-up, the overall rate of rehospitalization over the 1-year follow-up for an HF relapse, and the rate of rehospitalization during the first 3 months after inclusion into the study., Conclusions: The NATURE-HF study will fill a significant gap in the dynamic landscape of HF care and research. It will provide unique and necessary data on the management and outcomes of patients with HF. This study will yield the largest contemporary longitudinal cohort of patients with HF in Tunisia., Trial Registration: ClinicalTrials.gov NCT03262675; https://clinicaltrials.gov/ct2/show/NCT03262675., International Registered Report Identifier (irrid): DERR1-10.2196/12262., (©Leila Abid, Ikram Kammoun, Manel Ben Halima, Salma Charfeddine, Hedi Ben Slima, Meriem Drissa, Khadija Mzoughi, Dorra Mbarek, Leila Riahi, Saoussen Antit, Afef Ben Halima, Wejdene Ouechtati, Emna Allouche, Mehdi Mechri, Chedi Yousfi, Ali Khorchani, Omar Abid, Kais Sammoud, Khaled Ezzaouia, Imen Gtif, Sana Ouali, Feten Triki, Sonia Hamdi, Selim Boudiche, Marwa Chebbi, Mouna Hentati, Amani Farah, Habib Triki, Houda Ghardallou, Haythem Raddaoui, Sofien Zayed, Fares Azaiez, Fadwa Omri, Akram Zouari, Zine Ben Ali, Aymen Najjar, Houssem Thabet, Mouna Chaker, Samar Mohamed, Marwa Chouaieb, Abdelhamid Ben Jemaa, Haythem Tangour, Yassmine Kammoun, Mahmoud Bouhlel, Seifeddine Azaiez, Rim Letaief, Salah Maskhi, Aymen Amri, Hela Naanaa, Raoudha Othmani, Iheb Chahbani, Houcine Zargouni, Syrine Abid, Mokdad Ayari, Ines ben Ameur, Ali Gasmi, Nejeh ben Halima, Habib Haouala, Essia Boughzela, Lilia Zakhama, Soraya ben Youssef, Wided Nasraoui, Mohamed Rachid Boujnah, Nadia Barakett, Sondes Kraiem, Habiba Drissa, Ali Ben Khalfallah, Habib Gamra, Salem Kachboura, Leila Bezdah, Hedi Baccar, Sami Milouchi, Wissem Sdiri, Skander Ben Omrane, Salem Abdesselem, Alifa Kanoun, Karima Hezbri, Faiez Zannad, Alexandre Mebazaa, Samir Kammoun, Mohamed Sami Mourali, Faouzi Addad. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 27.10.2021.)

Aim: To determine the prevalence and the risk factors of hypogonadism in men with chronic renal failure (CRF)., Methods: We conducted a cross sectional analysis in 48 men with CRF. Total testosterone, prolactin, and gonadotropins were measured in all patients. Hypogonadism was defined by a low level (<10 nmol/l) or a low normal level (10-14 nmol/l) of total testosterone., Results: The mean age was 53.31±10.22 years. Renal impairment was mild, moderate, severe and at end stage in 9,14,4 and 21 patients, respectively. Nineteen patients had been undergoing extra-renal purification. The average of total testosterone was 13.44±6.17 nmol/L. It was lower in patients with diabetic nephropathy (p=0.004). Hypogonadism was diagnosed in 22 patients (46 %). In this group, gonadotropins were normal in 21 cases and elevated in only one case. Hyperprolactinemia was retained in six patients. Type 2 diabetes (OR: 3.96; p=0.02) and diabetic nephropathy (OR=4.26; p=0.01) were the only risk factors of hypogonadism in our patients., Conclusion: Our results had demonstrated a high prevalence of hypogonadism in males with chronic renal failure. This hormone disorder was associated with type 2 diabetes and diabetic nephropathy.

Four hundred and fifty bacteria were evaluated for antagonistic activity against bacterial soft rot of potato caused by Pectobacterium carotovorum sp strain II16. A strain Ar10 exhibiting potent antagonist activity has been identified as Bacillus amyloliquefaciens on the basis of biochemical and molecular characterization. Cell free supernatant showed a broad spectrum of antibacterial activity against human and phytopathogenic bacteria in the range of 10-60 AU/mL. Incubation of P. carotovorum cells with increasing concentrations of the antibacterial compound showed a killing rate of 94.8 and 96% at MIC and 2xMIC respectively. In addition, the antibacterial agent did not exert haemolytic activity at the active concentration and has been preliminary characterized by TLC and GC-MS as a glycolipid compound. Treatment of potato tubers with strain Ar10 for 72 h significantly reduced the severity of disease symptoms (100 and 85.05% reduction of necrosis deep / area and weight loss respectively). The same levels in disease symptoms severity was also recorded following treatment of potato tubers with cell free supernatant for 1 h. Data suggest that protection against potato soft rot disease may be related to glycolipid production by strain Ar10. The present study affords new alternatives for anti-Pectobacterium carotovorum bioactive compounds against the soft rot disease of potato., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

A strain producing chitinase, isolated from potato stem tissue, was identified as Bacillus licheniformis by biochemical properties and 16S RNA sequence analysis. Statistical experimental designs were used to optimize nine independent variables for chitinase production by B. licheniformis AT6 strain in submerged fermentation. Using Plackett-Burman design, (NH 4 ) 2 SO 4 , MgSO 4 .7H 2 O, colloidal chitin, MnCl 2 2H 2 O, and temperature were found to influence chitinase production significantly. According to Box-Behnken response surface methodology, the optimal fermentation conditions allowing maximum chitinase production were (in gram per liter): (NH 4 ) 2 SO 4 , 7; K 2 HPO 4 , 1; NaCl, 1; MgSO 4 .7H 2 O, 0.1; yeast extract, 0.5; colloidal chitin, 7.5; MnCl 2 .2H 2 O, 0.2; temperature 35 °C; pH medium 7. The optimization strategy led to a 10-fold increase in chitinase activity (505.26 ± 22.223 mU/mL versus 50.35 ± 19.62 mU/mL for control basal medium). A major protein band with a molecular weight of 61.9 kDa corresponding to chitinase activity was clearly detected under optimized conditions. Chitinase activity produced in optimized medium mainly releases N-acetyl glucosamine (GlcNAc) monomer from colloidal chitin. This enzyme also acts as an exochitinase with β-N-acetylglucosaminidase. These results suggest that B. licheniformis AT6 secreting exochitinase is highly efficient in GlcNAc production which could in turn be envisaged as a therapeutic agent or as a conservator against the alteration of several ailments.

Background: Acute coronary syndromes (ACS) are complex and polygenic diseases which are a real problem of public health. These syndromes require multidisciplinary studies to understand the pathogenesis mechanisms. Our study aims to evaluate the endothelin-1 (ET-1) serum concentration in Tunisian coronary compared to controls healthy, as well as the study of the impact of an intronic polymorphism A (8002) G of pre-pro-endothelin-1 Gene (inactive precursor of ET-1) on the change in serum endothelin-1 and in the susceptibility to Acute coronary syndrome (SCA)., Methods: Our samples were subdivided into coronary patients (157) and healthy subjects (142). The quantification of the ET-1 concentration was performed by high performance liquid chromatography, the identification of the different genotypes of the polymorphism A(8002)G was made by PCR-RFLP. The association between the ET-1 concentration and identified genotypes was realized by adapted software for descriptive statistics, Statistical Package for the Sociological Sciences (SPSS v 21.0)., Results: Our study showed that the concentration of ET-1 was significantly higher in patients compared to controls and that the mutated allele prevails in patients F (G) = 0.78 and there is a minority in controls F (G) = 0.3. Secondly the homozygous genotype GG is associated with higher concentrations of ET-1 in patients and controls, heterozygous genotype AG is associated with intermediaries' values and AA genotype is related to lower values., Conclusion: Although the polymorphism studied is an intronic polymorphism, it is involved in the change in serum concentration of ET-1 and is a candidate gene in susceptibility to SCA. Cardiovascular diseases are "polygenic" pathology and do not obey of the law for transmission of Mendel.

In the present study, the synergism of the lipopeptide bacillomycin D in combination with the polyene amphotericin B against pathogenic Candida species is described along with their potential cytotoxicity against mammalian cells. Bacillomycin D inhibited the growth of various Candida species at minimal concentrations from 12.5 to 25 μg ml(-1). Furthermore, it showed a synergistic effect with the antifungal drug amphotericin B in inhibiting the growth of Candida strains, with fractional inhibitory concentration indices ranging from 0.28 to 0.5. Time killing studies revealed a >2-log reduction in the viability of Candida albicans ATCC 10231 cells after 3 h incubation with the combination amphotericin B plus bacillomycin D, at their subinhibitory concentration. Interestingly, when the two drugs were used together at those dosages displaying a synergism in the anti-Candida activity, no cytotoxic effect was observed against mammalian cells. Therefore, the combination bacillomycin D/amphotericin B may represent a valid alternative to conventional antifungals for topical treatment of C. albicans infections. To the best of our knowledge, this is the first report describing the in vitro interaction between the antifungal drug amphotericin B and bacillomycin D against pathogenic Candida species., (© FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Several volatile organic compounds (VOCs) producing endophyte bacteria were isolated from the leaves of olive trees and tested for their antifungal activity against several pathogenic fungi. An antagonistic strain called P2 showed 97 % of homology with Pseudomonas sp. strains on the basis of its 16S rDNA sequence and biochemical properties. P2 strain drastically inhibited the growth of Rhizoctonia solani mycelia (86 %) at 5 day-post-confrontation (dpc) and strongly reduced fungi infection on potato slices at 10(7) bacteria ml(-1) for 3 and 7 dpc. P2 strain was also positive for protease activity as well as siderophore production. Light microscopy analysis showed that treatment of R. solani mycelia with P2 strain induced thickening of the cell-wall, vesiculation of protoplasm and blockage of fungal hyphae branching. VOCs analysis using GC-MS allowed the detection of two major products with m/z of 93.9910 and 125.9630 corresponding to dimethyl disulfide and dimethyl trisulfide respectively. VOCs-producing P2 strain could be a promising agent in the protection of tuber crops against fungal diseases.