Analysis of the bacterial diversity in Moroccan Jben cheese using TTGE, DGGE, and 16S rRNA sequencing.

This research investigated the physicochemical, microbiological, and bacterial diversity of Jben cheese, a popular artisanal variety in Morocco. The bacterial diversity was explored using culture-independent methods, including temporal temperature gel electrophoresis (TTGE), denaturing gradient gel electrophoresis (DGGE), and high-throughput sequencing (HTS). Significant intra-sample differences were observed for most physicochemical parameters within each milk type, while inter-sample differences occurred between cow and goat cheeses for dry matter and ash. Jben cheese exhibited distinct characteristics, with low pH values of 3.96, 4.16, and 4.18 for cow, goat, and mixed cheeses, respectively. Goat cheeses had higher fat (49.23 g/100 g), ash (1.91 g/100 g), and dry matter (36.39 g/100 g) than cow cheeses. All cheeses displayed high microbial counts, with a notable prevalence of the lactic acid bacteria (LAB) group, averaging 8.80 ± 0.92 log CFU/g. Jben cheese also displayed high contamination levels with total coliforms, faecal coliforms, yeast, and molds. Fatty acid profiling revealed fraudulent practices in Jben cheese marketing, with cow or mixed cheeses sold as goat cheese, as proven by low capric acid concentration. HTS analysis of Jben cheese identified ten genera and twenty-four species, highlighting Lactococcus lactis as predominant. TTGE and DGGE confirmed the presence of L. lactis but failed to provide the detailed profile achieved through HTS analysis. HTS has been demonstrated to be more reliable, whereas TTGE/DGGE methods, though informative, were more time-consuming and less reliable. Despite limitations, the combined use of TTGE, DGGE, and HTS provided a comprehensive view of indigenous bacterial communities in Jben cheese, identifying L. lactis as the main species.

Chemical profiling and bioactivities of essential oils from Thymus capitatus and Origanum compactum against Tribolium castaneum.

The use of essential oils has emerged as an ecofriendly solution for controlling different pests, particularly insects of stored products. Essential oils (EOs) from Thymus capitatus (TC) and Origanum compactum (OC) have received less attention for these bioactivities. Therefore, our study aimed to assess the repellent, antifeedant and contact toxicity of their EOs against a major stored product pest Tribolium castaneum. Besides, GC-MS was also carried out to determine the compounds responsible for the observed bioactivities. Regarding contact toxicity, LC50 values were 0.58 and 0.35 µL/cm2 for TC and OC after 24 h of exposure, respectively. For the repellent effect, the percentage of repellency (PR) was variable across different concentrations and exposure durations. TC exhibited the best PR (98%) after 3 h of exposure at 0.031 µL/cm2. For prolonged repulsive effect (24 h), TC sustained its repulsive efficacy with a PR of 90% at 0.062 µL/cm2 followed by OC with a PR of 88% at 0.125 µL/cm2. As for the antifeedant effect, both EOs had a significant impact on nutritional indexes, especially the feeding deterrent index and relative consumption rate. OC displayed a notable effect, causing 59% of feeding deterrence at 1.92 µL/pellet. These multifaced effects can be explained by the high content of carvacrol in both EOs (OC: 90% and TC: 78%). These multifaced effects demonstrated through different exposure routes and bioassays promote the use of T. capitatus and O. compactum EOs as a sustainable management strategy to control T. castaneum.

Marine collagen: Unveiling the blue resource-extraction techniques and multifaceted applications.

Marine organisms such as fish and shellfish are composed of compounds with properties and characteristics that have been proven useful in a variety of sectors such as cosmetics, healthcare (wound healing), food industries, and tissue engineering. Collagen extraction from fish waste as a "blue resource" has attracted research attention over the past decade. Around 75 % of fish waste contains a high concentration of collagen. This has driven research in the conversion of these low-cost by-products into valuable products. Collagen extracted by acidic or/and enzymatic methods is gaining a lot of attention today due to its low cost and high yield. Fermentation and enzymatic hydrolysis stand out as one of the most environmentally sustainable and ecologically friendly methods for collagen extraction. Because of its great biocompatibility, excellent bioactivity, and low antigenicity, marine collagen is receiving more attention. Furthermore, collagen-derived peptides may exhibit interesting antioxidant activity, potent antihypertensive activity, and antimicrobial activity against different strains of bacteria. This review focuses on the advancements in extraction and detection methods of marine collagen, both from a technological and legislative standpoint, in addition to exploring its diverse range of application domains.

Promoting the growth of Sulla flexuosa L. by endophytic root nodule bacteria authors and affiliations.

Legume plants rely upon multipartite interactions between rhizobia and bacterial endophytes within root nodules to facilitate plant growth. This study aimed to isolate and identify indigenous endophytic bacteria from root nodules of Sulla aculeolata L. in Northeast Morocco. Based on their tri-calcium phosphate (TCP) solubilization capacity, five endophytes were chosen for further evaluation of their plant growth traits. All isolates were hydrogen cyanide (HCN) and siderophore producers, while only BCH24 tested positive for ACC deaminase activity. Indole-3-acetic acid (IAA) synthesis ranged from 1.27 mgL- 1 to 2.89 mgL- 1, while soluble phosphate concentrations was between 7.99 mg L- 1 and 110.58 mg L- 1. Additionally, all the endophytes were able to produce more than two lytic enzymes. Based on the analysis of 16 S rRNA gene sequences five isolates were identified as Enterobacter sp (BCH13, BCH2), Pseudomonas sp (BCH16, BCH24), and Serratia sp (BCH10). The strains inhibited the growth of three phytopathogenic fungi, with BCH13 exhibiting the highest rate against Aspergillus ochraceus (45%), followed by BCH24 against Fusarium oxysporum (40%) and Botrytis cinerea (35%), respectively. In vivo inoculation of halotolerant strains Enterobacter hormaechei (BCH13) and Pseudomonas moraviensis (BCH16) under gnotobiotic conditions revealed that co-inoculation with Rhizobium sullae KS6 improved plant development compared to single inoculation, making it a promising eco-friendly bio-inoculant for legume Sulla flexuosa L. production.

Genotypic diversity of multi- and pre-extremely drug-resistant Mycobacterium tuberculosis isolates from Morocco.

In Morocco, the prevalence of multidrug resistant tuberculosis (MDR-TB) continues to increase especially within previously treated cases; these MDR cases may evolve to extensively drug resistant tuberculosis (XDR-TB) raising major concern to TB control programs. From an epidemiological window, scarce informations are available about the genetic diversity of Mycobacterium tuberculosis (MTB) strains fueling these forms of resistance. The aim of this study was to assess to genetic diversity of MDR-MTB strains. Hence, this prospective study was conducted on patients diagnosed with MDR-TB at Pasteur Institute of Casablanca from 2010 to 2013. A total of 70 MDR-MTB isolates were genotyped by spoligotyping and 15-loci MIRU-VNTR methods. Spoligotyping generated four orphan patterns, five unique profiles whereas 61 strains were grouped in nine clusters (2 to 25 strains per cluster), the clustering rates being 87.1%. Subtyping by 15 loci MIRU-VNTR splitted all clusters already established by spoligotyping and generated 70 unique profiles not recognized in SITVIT2 database; clustering rate was equal to zero. HGDI analysis of 15 loci MIRU demonstrated that eight out of 15 loci were highly discriminant. Of note, all pre-XDR strains belongs to many clades, meaning that there no association between gyrA mutants and particular clade. Overall, the data generated by this study (i) describe the population structure of MDR MTBC in Morocco which is highly homogenous, (ii) confirm that TB in Morocco is almost exclusively transmitted by modern and evolutionary lineages with high level of biodiversity seen by MIRU, and (iii) validate the use of optimized 15-loci MIRU-VNTR format for future investigations in Morocco.

Nasal carriage of Staphylococcus aureus in farm animals and breeders in north of Morocco.

BACKGROUND: The objectives of this study were to determine for the first time, in Morocco, the nasal carriage rate, antimicrobial susceptibility profiles and virulence genes of Staphylococcus. aureus isolated from animals and breeders in close contact. METHODS: From 2015 to 2016, 421 nasal swab samples were collected from 26 different livestock areas in Tangier. Antimicrobial susceptibility phenotypes were determined by disk diffusion according to EUCAST 2015. The presence of nuc, mecA, mecC, lukS/F-PV, and tst genes were determined by Polymerase Chain Reaction (PCR) for all isolates. RESULTS: The overall S. aureus nasal carriage rate was low in animals (9.97%) and high in breeders (60%) with a statistically significant difference, (OR = 13.536; 95% CI = 7.070-25.912; p < 0.001). In general, S. aureus strains were susceptible to the majority of antibiotics and the highest resistance rates were found against tetracycline (16.7% in animals and 10% in breeders). No Methicillin-Resistant S. aureus (MRSA) was detected in animals and breeders. A high rate of tst and lukS/F-PV genes has been recovered only from animals (11.9 and 16.7%, respectively). CONCLUSION: Despite the lower rate of nasal carriage of S. aureus and the absence of MRSA strains in our study, S. aureus strains harbored a higher frequency of tst and lukS/F-PV virulence genes, which is associated to an increased risk of infection dissemination in humans. This highlights the need for further larger and multi-center studies to better define the transmission of the pathogenic S. aureus between livestock, environment, and humans.

Frequency of genomic mutations mediating resistance of Mycobacterium tuberculosis isolates to rifampicin in Northern Morocco.

Drug resistant tuberculosis (DR-TB) is challenging particularly in developing countries. As such, a previous investigation gave the first insight into the mutational status of the Rifampicin Resistance Determining Region (RRDR) of rpoB gene among a restricted number of MTB patients' residents in the Northern Morocco. The purpose of this study was to investigate rpoB mutation types and frequencies associated with resistance to Rifampicin in a larger panel of MTB patients and to evaluate the usefulness of these mutations to improve the diagnosis of resistance to Rifampicin. A panel of 301 consecutive sputum samples belonging to patients suscpected of having TB from Northern Morocco was collected at the Pasteur Institute of Tangier between 2014-2017. Samples were subjected to conventionel microbiological tests. Evaluation of rpoB muational status was assessed by PCR amplification and sequencing of the RRDR of the rpoB gene. DST results showed that 26.4% of strains were MDR. Sequencing results reported single point mutations in 36 of 65 RIFR isolates of which two had two mutations. Aminoacid substitutions in the codon Ser531Leu occurred at the highest frequency (34.46%). Overall, 10 aminoacid substitutions have been registered, and the H526S substitution was reported for the first time. The present study highlighted that resistance to RIF is a reliable marker of MDR-TB, the common mutations successfully detected in the rpoB 531, rpoB526 and rpoB516 codons provide a foundation for the implementation of molecular approaches such as Hain and GeneXpert as a routine tests to detect DR-TB. However, considerable work is still necessary to identify extensive mutations associated with DR-TB.

Virulence genes and antibiotic resistance of Pseudomonas aeruginosa isolated from patients in the Northwestern of Morocco.

INTRODUCTION: Pseudomonas aeruginosa is an ubiquitous bacterium causes various community-acquired and nosocomial infections. In this investigation, we aimed to screen the antibiotic susceptibility patterns and the prevalence of virulence factor genes in a set of Pseudomonas aeruginosa isolated from nosocomial and community-acquired infections in the Northwestern of Morocco. METHODOLOGY: A total of 155 of Pseudomonas aeruginosa strains were collected (January 2015 - December 2016) from nosocomial and community-acquired infections at hospital centers and clinical laboratories in the Northwestern of Morocco. Antimicrobial susceptibility test was performed by the standard disk diffusion method. In addition, PCR assays were used for screening five virulence encoding genes (lasB, algD, plcH, exoA, and exoS). RESULTS: Our results revealed that high level of antimicrobial resistance was detected towards aztreonam (27.1%) followed by meropenem (14.2%). The resistance to imipenem was significantly higher in strains isolated from nosocomial infections (12.7%) than strains isolated from community-acquired infections (1.5%). The results highlighted that lasB (98.7%) and exoS (98.7%) were the most frequent virulence genes. CONCLUSIONS: This survey provides data about phenotypic and genotypic properties of Pseudomonas aeruginosa emerged in the Northwestern of Morocco. It could be helpful for the health workers to improve infection control measures and to establish a surveillance system.

Cytotoxic, antioxidant and antimicrobial activities of Nerium oleander collected in Morocco

Objective: To investigate the cytotoxic, antioxidant and antibacterial activities of ethanolic and aqueous crude extracts of Nerium oleander (N. oleander) leaves. Methods: Cytotoxic activities were evaluated by WST-1 bioassay on two human cancer cell lines, namely human colon adenocarcinoma cell line HT-29 and human breast cancer cell line MDA-MB-231. The antioxidant property of N. oleander extracts was assessed by DPPH scavenging and β-carotene bleaching tests. The agar disc diffusion method was used for the determination of antimicrobial activity against different strains. Results: Using cell viability indices, the WST-1 test revealed that both extracts reduced cell viability in both cell lines. Our results also showed that aqueous extract was more active than ethanolic extract, with IC

Molecular characterization of mutations associated with resistance to second-line tuberculosis drug among multidrug-resistant tuberculosis patients from high prevalence tuberculosis city in Morocco.

BACKGROUND: The emergence of extensively drug-resistant tuberculosis (XDR-TB) has raised public health concern for global TB control. Although multi drug-resistant tuberculosis (MDR- TB) prevalence and associated genetic mutations in Morocco are well documented, scarce information on XDR TB is available. Hence, the evaluation of pre-XDR and XDR prevalence, as well as the mutation status of gyrA, gyrB, rrs, tlyA genes and eis promoter region, associated with resistance to second line drugs, is of great value for better management of M/XDR TB in Morocco. OBJECTIVES: To evaluate pre-XDR and XDR prevalence, as well as the mutation status of gyrA, gyrB, rrs, tlyA genes and eis promoter region, associated with resistance to second line drug resistance, in 703 clinical isolates from TB patients recruited in Casablanca, and to assess the usefulness of molecular tools in clinical laboratories for better management of M/XDR TB in Morocco. METHODS: Drug susceptibility testing (DST) was performed by the proportional method for first line drugs, and then the selected MDR isolates were tested for second line drugs (Ofloxacin, Kanamycin, Amikacin and Capreomycin). Along with DST, all samples were subjected to rpoB, katG and p-inhA mutation analysis by PCR and DNA sequencing. MDR isolates as well as 30 pan-susceptible strains were subjected to PCR and DNA sequencing of gyrA, gyrB, rrs, tlyA genes and eis promoter, associated with resistance to fluoroquinolones and injectable drugs. RESULTS: Among the 703 analysed strains, 12.8% were MDR; Ser531Leu and Ser315Thr being the most common recorded mutations within rpoB and katG genes associated with RIF and INH resistance respectively. Drug susceptibility testing for second line drugs showed that among the 90 MDR strains, 22.2% (20/90) were resistant to OFX, 2.22% (2/90) to KAN, 3.33% (3/90) to AMK and 1.11% (1/90) to CAP. Genotypic analysis revealed that 19 MDR strains harbored mutations in the gyrA gene; the most recorded mutation being Asp91Ala accounting for 47.6% (10/21), and 2 isolates harbored mutations in the promoter region of eis gene. No mutation was found in gyrB, rrs and tlyA genes. Moreover, none of the pan-susceptible isolates displayed mutations in targeted genes. CONCLUSION: Most of mutations associated with SLD resistance occurred in gyrA gene (codons 90-94) and eis promoter region. These findings highlight the impact of mutations in gyrA on the development of fluroquinolones resistance and provide the first estimates of the proportion of pre-XDR-TB among MDR-TB cases in Morocco.

Performance of GenoType® MTBDRplus assay in the diagnosis of drug-resistant tuberculosis in Tangier, Morocco.

OBJECTIVES: In Morocco, tuberculosis (TB) is a major public health problem with high morbidity and mortality. The main problem faced by the national TB programme is the high rate of drug-resistant (DR), particularly multi-drug resistant (MDR) strains. Diagnosis of DR-TB is mainly performed by conventional techniques that are time consuming with limited efficacy. In 2014, the GenoType® MTBDRplus assay was introduced in Morocco for drug susceptibility testing (DST). In this regard, the present study was planned to assess the diagnostic accuracy of the GenoType® MTBDRplus assay. METHODS: A total of 70 samples from suspected TB cases in Tangier (Morocco) were analysed by conventional DST and GenoType® MTBDRplus assay. RESULTS: Among the 70 samples, 37.1% were MDR, whereas monoresistance to isoniazid (INH) and rifampicin (RIF) was detected in 186% and 17.1% of strains, respectively, by DST. Using the GenoType® MTBDRplus approach, 12 isolates (17.1%) were identified as INH monoresistant, 9 (12.9%) as RIF monoresistant and 26 (37.1%) as MDR. rpoB531 and katG315 mutations were the most common mutations associated with resistance to RIF and INH, respectively. Significantly, all phenotypically MDR strains were also MDR by GenoType® MTBDRplus. The sensitivity of GenoType® MTBDRplus was 92.1% for RIF resistance and 97.4% for INH resistance, whereas the specificity was 100% for the two tested drugs. CONCLUSIONS: GenoType® MTBDRplus assay is a rapid, reliable and accurate tool for the detection of DR-TB in clinical specimens. Its routine use will be of a great interest to prevent the dissemination of DR-TB in the community.

Nasal carriage of sequence type 22 MRSA and livestock-associated ST398 clones in Tangier, Morocco.

INTRODUCTION: This study aimed to provide data of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage as well as to determine the genetic lineages of this circulating MRSA in the Tangier community. METHODOLOGY: Between 2012 and 2013 two subpopulations consisting of randomly chosen healthy volunteers and outpatients in 11 healthcare facilities were screened. The antibiotic resistance phenotype was determined by disk diffusion. Toxin Panton-Valentin Leukocidin (PVL), toxic shock syndrome toxin-1 gene (tst), and mecA were detected by polymerase chain reaction (PCR). Nasal swabs were obtained from persons with no identified risk factors for MRSA acquisition. MRSA molecular typing was performed by pulsed-field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec, and Staphylococcus protein A (spa) typing. RESULTS: A total of400 subjects (33.3%) were nasally colonized with S. aureus, and 17 (1.4%) were nasal carriers of MRSA. The analysis did not identify age, gender, and the two subpopulations as predictors for MRSA colonization. MRSA were more likely to harbor the tst gene (p < 0.05). This work highlighted a low prevalence of nasal MRSA carriage, with 52.94% belonging to sequence type (ST) ST22. The remaining isolates were distributed as singletons (ST8, ST1, and ST398), whereas approximately one-third of MRSA was not identified, including three novel spa-types (t13247, t13248, and t13249). CONCLUSIONS: Although we highlighted the current clones present in the Tangier community, they are limited in space and time. Therefore, further studies would be required to obtain a comprehensive picture of the dissemination of MRSA in the community, hospital, and livestock.

Antioxidant-enzyme reaction to the oxidative stress due to alpha-cypermethrin, chlorpyriphos, and pirimicarb in tomato (Lycopersicon esculentum Mill.).

Tomato (Lycopersicon esculentum Mill.) becomes one of the world's foremost vegetables, and its world production and consumption have increased fairly quickly. The capacity to induce oxidative stress in tomato plant, exposed to three xenobiotics such as alpha-cypermethrin, chlorpyriphos, and pirimicarb, was investigated by the evaluation of lipid peroxidation by measuring malondialdehyde (MDA) rate; also, we studied the response of tomato to this stress by assessing the response of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione-s-transferase (GST), and glutathione reductase (GR). The effect of the insecticides was observed using four concentrations (25, 50, 75, and 100%) for germinating seeds and only the recommended concentration in agriculture (100%) for growing plants. Our results show an important accumulation of MDA, demonstrating the increase of lipid peroxidation in consequence of the excessive reactive oxygen species (ROS) production due to insecticide treatment. In response to this oxidative stress in tomato seedlings and plants, the activities of antioxidant-enzyme system were generally enhanced. The electrophoretic analysis showed also the apparition of new isoenzymes as the case for CAT and POD.

Microbiological and physicochemical characterization of dry-cured Halal goat meat. Effect of salting time and addition of olive oil and paprika covering.

The objective of this work was to define a simple technological process for dry-cured Halal goat meat elaboration. The aims of this study were to analyze physicochemical parameters and to enumerate the microbial population at the end of the different manufacturing processes (two salting times and the addition of olive oil and paprika covering) on 36 units of meat product. A total of 532 strains were isolated from several selective culture media and then identified using classical and molecular methods. In general, salt effect and the addition of olive oil and paprika were significant for all the studied microbial groups as well as on NaCl content and water activity. Molecular analysis proves that staphylococci, especially Staphylococcus xylosus and Staphylococcus equorum, were the most common naturally occurring microbiota. The best manufacturing process would be obtained with a longer salting time and the addition of the olive oil and paprika covering.

Chemical composition and antioxidant properties of Laurus nobilis L. and Myrtus communis L. essential oils from Morocco and evaluation of their antimicrobial activity acting alone or in combined processes for food preservation.

BACKGROUND: This study describes the antioxidant and antimicrobial activity of Laurus nobilis L. and Myrtus communis L. essential oils (EOs). This is the first report of the synergistic antimicrobial effect of these EOs in combination with physical food preservation treatments. RESULTS: EOs obtained by steam distillation from aerial parts of Laurus nobilis and Myrtus communis were analysed by using gas chromatography-mass spectrometry. The main compounds were 1,8-cineole and 2-carene (L. nobilis EO); and myrtenyl acetate, 1,8-cineole and α-pinene (M. communis EO). L. nobilis EO showed higher antioxidant activity than M. communis EO in three complementary antioxidant tests. Although antimicrobial activity tests demonstrated the effectiveness of L. nobilis EO and the lack of bactericidal effect of M. communis EO, synergistic lethal effects were observed when combining each EO (0.2 µL mL(-1)) with mild heat (54°C for 10 min) or high hydrostatic pressure (175-400 MPa for 20 min). In contrast, combination of EOs with pulsed electric fields (30 kV cm(-1) for 25 pulses) showed no additional effects. CONCLUSION: This study shows the great potential of these EOs in combined treatments with mild heat and high hydrostatic pressure to obtain a higher inactivation of foodborne pathogens, which might help in the design of safe processes applied at low intensity.

Characterization of bottom ash from two hospital waste incinerators in Rabat, Morocco.

The uncontrolled disposal of bottom ash generated by the incineration units of hazardous and infected wastes in developed countries are the main cause of significant damage, such as contamination of the soil, as well as surface and underground waters, which may put both the environment and public health at risk. In Morocco, little information is available on the chemical properties of the resulting ashes. In this study, 16 hospital waste ash samples were collected from the incinerators of the two main hospitals in Rabat: Ibn Sina and Cheikh Zayd. A series of tests was conducted, including particle size distribution, mineralogical and chemical composition, and heavy metal leaching behaviour. The results showed that the samples were composed mainly of P2O5 (18%), SiO2 (17%), Na2O (16%), CaO (14%) and SO3 (10%). Moreover, chemical analysis clearly demonstrated that medical waste (MW) contains large amounts of waste generated by domestic activities in the hospital, with a lack of sorting system in the monitoring of MW. Furthermore, the ashes contained high concentrations of heavy metals such as zinc, lead, chromium and nickel with a vast range of 0.5-25071 mg/kg. Leaching tests showed that the extracted amounts of all the heavy metals were lower, with concentrations < 2.85 mg/kg. Comparison of the corresponding heavy metal concentrations with the limit values set by the Council Decision 2003/33/EC allowed us to conclude that bottom ashes meet the waste acceptance criteria regarding these heavy metals.

Synergistic combinations of high hydrostatic pressure and essential oils or their constituents and their use in preservation of fruit juices.

This work addresses the inactivation achieved with Escherichia coli O157:H7 and Listeria monocytogenes EGD-e by combined processes of high hydrostatic pressure (HHP) and essential oils (EOs) or their chemical constituents (CCs). HHP treatments (175-400 MPa for 20 min) were combined with 200 µL/L of each EO (Citrus sinensis L., Citrus lemon L., Citrus reticulata L., Thymus algeriensis L., Eucalyptus globulus L., Rosmarinus officinalis L., Mentha pulegium L., Juniperus phoenicea L., and Cyperus longus L.) or each CC ((+)-limonene, α-pinene, ß-pinene, p-cymene, thymol, carvacrol, borneol, linalool, terpinen-4-ol, 1,8-cineole, α-terpinyl acetate, camphor, and (+)-pulegone) in buffer of pH 4.0 or 7.0. The tested combinations achieved different degrees of inactivation, the most effective being (+)-limonene, carvacrol, C. reticulata L. EO, T. algeriensis L. EO and C. sinensis L. EO which were capable of inactivating about 4-5 log(10) cycles of the initial cell populations in combination with HHP, and therefore showed outstanding synergistic effects. (+)-Limonene was also capable of inactivating 5 log(10) cycles of the initial E. coli O157:H7 population in combination with HHP (300 MPa for 20 min) in orange and apple juices, and a direct relationship was established between the inactivation degree caused by the combined process with (+)-limonene and the occurrence of sublethal injury after the HHP treatment. This work shows the potential of EOs and CCs in the inactivation of foodborne pathogens in combined treatments with HHP, and proposes their possible use in liquid food such as fruit juices.

Chemical composition and antimicrobial activity of essential oils of Thymus algeriensis, Eucalyptus globulus and Rosmarinus officinalis from Morocco.

BACKGROUND: The present study reports on the antimicrobial activity and chemical composition of the essential oils (EOs) of Thymus algeriensis, Eucalyptus globulus and Rosmarinus officinalis from Morocco. RESULTS: The composition of these species was analysed by GC-MS, and 65 components were identified. Eucalyptus globulus EO showed a great similarity with EOs from other regions, with 1,8-cineole (79.85%) the major component. Also rich in this constituent was Rosmarinus officinalis (43.99%). However, the chemical profile of Thymus algeriensis was rather different, and for the first time such a high content of borneol (23.48%) has been described in this EO. The antimicrobial activity of these species has also been studied against seven pathogenic and spoiling bacteria of significant importance. According to the results, Thymus algeriensis showed the best bacteriostatic and bactericidal effect, followed by Eucalyptus globulus and Rosmarinus officinalis. CONCLUSIONS: As far as we know this is the first time that minimum inhibitory and bactericidal concentration values have been reported for Eucalyptus globulus EO. Our data support the possible use of this EO as well as Thymus algeriensis EO, as potential natural agents in preservatives for food and pharmaceutical products.

Antibiotic resistance patterns of bacterial strains isolated from Periplaneta americana and Musca domestica in Tangier, Morocco.

BACKGROUND: Flies and cockroaches are two insects in close contact with human beings. They are carriers of human pathogenic bacteria on the external areas of their bodies or in their digestive tracts. This study examines Periplaneta americana and Musca domestica collected from the residential areas of six districts in Tangier, Morocco. METHODOLOGY: In total, 251 bacteria were isolated from external areas of the participants' bodies and the antimicrobial susceptibility was calculated. RESULTS: The predominant bacterial species included Escherichia coli (17.9%), Klebsiella spp. (14.7%), Providencia spp. (9.6%), Staphylococcus spp. (15.1%) and Enterococcus spp. (11.6%). The study showed no difference between the species of bacterial strains from American cockroaches and houseflies. Carbapenems and aminoglycosides were active against 100% of the Gram-negative bacilli isolated in this study. Staphylococcus spp. strains were susceptible to linezolid, vancomycin, daptomycin, levofloxacin and cotrimoxazole, and no antibiotic resistance was found in Enterococcus spp. CONCLUSIONS: In our setting, although both cockroaches and flies collected from residential areas may be vectors of human pathogenic bacteria, the infections caused by them are easily treatable as a result of the high susceptibility of their bacteria to antibiotics routinely used in the community or in hospitals.

Characterization of Salmonella Enteritidis isolated from foods and patients in northern Morocco.

OBJECTIVES: This study aimed to investigate Salmonella Enteritidis strains isolated from human and food sources in the north of Morocco by means of phenotypic and genotypic methods. METHODOLOGY: Fifteen isolates from humans and food were submitted to phage typing, XbaI-macrorestriction (pulsed field gel electrophoresis [PFGE]), enterobacterial repetitive intergenic consensus (ERIC-PCR), antimicrobial susceptibility testing, and PCR assay targeting the spvR and invA genes. RESULTS: Six fingerprinting profiles were obtained with the ERIC-PCR method, four with PFGE profiling, five with antimicrobial resistance, three with phage typing, and only one with plasmid profiling. spvR gene was detected in six strains, which did not harbour plasmids of 90 kb. CONCLUSIONS: The conclusions of this study are drawn from a limited number of isolates. It would be desirable to investigate a greater and more diverse population of Salmonella isolates. S. Enteritidis was genotyped and showed four different patterns by PFGE and six by ERIC-PCR. Accordingly, high genetic similarity and limited genetic diversity were found for these strains from north of Morocco.