Dear Label_Name,

Greetings! I hope you are well.

I am writing on behalf of an international publishing house, Science and Education Publishing, USA (http://www.sciepub.com).

Science and Education Publishing (SciEP) is a multidisciplinary open access publisher of Journals covering the fields of Science, Technology and Medicine. All SciEP publications are subject to high-quality peer review, editorial and production processes and are freely available online.

Welcome to the April, 2013 edition of SciEP newsletter, providing monthly summaries of articles on science & education related topics of interest to scientist and professionals. The mission of our journals is to provide an open access forum for publishing new findings on issues pertinent to scientific and academic field. We also invite you to submit original research papers, review articles, short reports, or case studies are considered for publication in our Multidisciplinary Journals.

American Journal of Public Health Research
DOI: 10.12691/ajphr-1-1-3

The Implementation of a Tele-Homecare System with Service Oriented Architecture and HL7 Message Transmission Standard
Ching-Sung Wang

American Journal of Medical and Biological Research
DOI: 10.12691/ajmbr-1-1-2

The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico
Lelevich Sergey Vladimirovich, Khrustalev Vladislav Victorovich, Barkovsky Eugene Victorovich, Shedogubova Tatyana Aleksandrovna

American Journal of Medical Sciences and Medicine
DOI: 10.12691/ajmsm-1-1-1

Clinical and Histological Features in Wegener Granulomatosis
Li Cavoli Gioacchino, Passantino Rita, Bono Luisa, Tortorici Calogera, Ferrantelli Angelo, Giammarresi Carlo, Rotolo Ugo

American Journal of Infectious Diseases and Microbiology
DOI: 10.12691/ajidm-1-1-2

The Curse of Lymphatic Filariasis: Would the Continual Use of Diethylcarbamazine Eliminate this Scourge in Papua New Guinea?
Anne Lanham, Lillian Mwanri

We have released issues of some journals on February 2013.
American Journal of Public Health Research
American Journal of Medical Sciences and Medicine
American Journal of Medical and Biological Research
American Journal of Pharmacological Sciences
American Journal of Clinical Medicine Research
American Journal of Nursing Research
American Journal of Cancer Prevention
American Journal of Medicine Studies
American Journal of Infectious Diseases and Microbiology
American Journal of Cardiovascular Disease Research
American Journal of Biomedical Research
American Journal of Mechanical Engineering
American Journal of Microbiological Research
Journal of Preventive Medicine
American Journal of Food and Nutrition
American Journal of Hypertension Research
American Journal of Sports Science and Medicine
Journal of Cancer Research and Treatment
American Journal of Zoological Research
Journal of Biomedical Engineering and Technology
American Journal of Microbiological Research
Biomedical Science and Engineering

We are pleased to announce that submissions are now being accepted for peer review for all the journals across all our subject areas in SciEP.

Please submit your manuscript via our online submission system:
http://www.sciepub.com/author/signin

To unsubscribe from our mailing list, please click on the following link: unsubscribe

I am looking forward to hearing from you.

Kind regards,

David Rain
Email:join@sciepub.com
Science and Education Publishing (http://www.sciepub.com)

Profile and Antibiotic Resistance Genes of Escherichia coli Strains Isolated from Ready-to-Eat Raw Mixed Vegetables Salads in Collective Catering in Abidjan, Côte D’Ivoire

Toé E.*, Dadié A., Dako E., Blé Y.C., Toty A., Loukou G., Djè K.M.

Laboratory of biotechnology and food microbiology, Department of Food Science and Technology, University of Nanguy Abrogoua, 02 BP 801 Abidjan 02, Cote d’Ivoire

Abstract: In recent years many cases of food poisoning due to the consumption of vegetable salads contaminated with antibiotic-resistant strains of E. coli have been reported. The objective of the study was to detect the profile and the genetic factors of antibiotic resistance of Escherichia coli, isolated from ready-to-eat raw mixed vegetable salads, in catering. A total of 218 E. coli strains isolated from salads were confirmed by identification of iudA gene. Antibiotic resistance profile was determined by the agar diffusion method and by the detection of resistance genetic supports. Prevalence of E. coli resistant to antibiotics in vegetable salads was 70.2% with 28.4% of multi-resistant. Antibiotic resistance particularly concerned tetracycline (52.3%), streptomycin (38.5%) and to a lesser extent, nalidixic acid (15.6%). The genes aaa [3] -IV, CIMT, QnrA, tetA, tetB, cmlA and cat1 respectively conferring resistance to gentamicin, ampicillin, quinolones, tetracycline and chloramphenicol were highlighted. The study reveals that the risk of contamination by strains of E. coli resistant to antibiotics exist and require healthy control measures.

Keywords: vegetable salads, Escherichia coli, antibiotic resistance, collective catering, Abidjan

Citation: Toé E., Dadié A., Dako E., Blé Y.C., Toty A., Loukou G., Djè K.M., Profile and Antibiotic Resistance Genes of Escherichia coli Strains Isolated from Ready-to-Eat Raw Mixed Vegetables Salads in Collective Catering in Abidjan, Côte D’Ivoire. American Journal of Microbiological Research, 5 (6). 124-130. January 2017. doi:10.12691/ajmr-5-6-2

1. Introduction

Antibiotic resistance is a growing threat to public health worldwide [1]. It compromises the prevention and effective treatment of an increasing number of infections caused by bacteria. In addition, it increases the cost of health care by extending the length of hospital stays, requiring more intensive care and more expensive drugs [1].The numbers of infections due to these resistances are estimated at 2000000 in the United States with 23 000 deaths per year [2] and 386 000 in Europe in 2007 with 25 000 deaths per year [3]. In Africa, the few available data indicate that the region shares the global trend of increasing resistance [4]. In Ivory Coast, for some years, the National Research Center (CNR) of antibiotic resistance and the observatory of the resistance of microorganisms to anti-infective in Côte d’Ivoire (ORMICI) have sounded the alarm over the emergence of multi-resistant bacteria and the consequences that could result [5,6]. Enterobacteriaceae resistant to antibiotics including E. coli were isolated from: human biological products (faeces, urine, blood) [7,8,9], products from livestock [10,11,12], food [13], water [14], soil [15,16], faeces of domestic animals (dogs and cats) and birds of national park Thaï [17]. In some cases, studies have shown that resistances were carried by plasmids, assuming a horizontal transfer of resistance [18,19].

E. coli is a very important bacterium in public health, responsible for intestinal and extra-intestinal infections. Each year, E. coli strains are responsible for 2 million deaths worldwide, whether through intestinal or extra-intestinal infections [20]. Strains involved in intestinal infections are responsible for gastroenteritis and those responsible for extra-intestinal infections are associated with sepsis, urinary tract infections and neonatal meningitis [21]. In 2011, following the consumption of vegetables contaminated with a strains of Shiga toxin producing E. coli (STEC) serotype O104: H4 and resistant to several families of antibiotic, 3816 cases of bloody diarrhea, 845 cases of Hemolytic Syndrome and Uremic (SHU) and 54 deaths occurred [22].

Foods such as ready-to-eat raw mixed vegetable salads, usually eaten without prior cooking process, are frequently offered in catering in Abidjan. The situation of antimicrobial resistance and of the corresponding genetic supports in the bacteria carried by these vegetables remains very poorly documented.

The objective of the study was to determine the profile and genetic factors of antibiotic resistance among E. coli strains isolated from ready-to-eat raw mixed vegetable salads, served in collective catering.

2. Material and Methods

2.1. Sampling and Origin of E. coli Strains

A total of 218 strains of E. coli were isolated from ready to eat raw mixed vegetable salads in collective catering in Abidjan. Salads were collected from February to November 2015 in different restaurants in five municipalities (Abobo, Adjamé, Yopougon, Treichville, Cocody). After collection, the samples were transported in a cooler with ice packs.

2.2. Isolation of E. coli strains

The E. coli isolation was carried out on RAPID'E.coli 2 selective chromogenic medium (Bio-rad, France) according to ISO 16140. A subculture was carried out on tryptic soy (Sigma Aldrich, Canada) and incubated for 24 hours at 37C. The biochemical characteristics were determined according to the method of Le Minor and Richard [20].

2.3. Confirmation of the Identification of Strains

Confirmation of the identification of the strains was made by carrying out a polymerase chain reaction (PCR), according to the protocol of Maheux et al. [24]. It consisted in the identification of iudA gene, following the steps of extraction of DNA, amplification and revelation of amplification products.

2.3.1. Extraction of DNA

DNA was extracted by the heat shock method. Three to four colonies of 24h on trypticase soy agar (BBL, Canada) were bubbled through 200 μL of milli-Q water contained in Eppendorf tubes (Sigma Aldrich, Canada). The suspension obtained was heated for 10 minutes in the Marie bath (Fisher Scientific, USA) at 100°C. and transferred to ice for 1 min. After centrifugation at 6000 rpm for 10 min, 100 μl of the supernatant was recovered in an Eppendorft tube containing 100 μl of milli-Q water, homogenized and stored at 4°C. The concentration and purity of DNA was determined by measuring the absorbance ratio of A260 / A280 with a spectrophotometer (Ultrospec 2000 Techne genius, USA). The extracted DNA was used both for confirmation of the identification of strains and for the detection of virulence genes. The extracted DNA was used both for confirmation of the identification of strains and for the detection of antibiotic resistant genes.

2.3.2. Amplification

Amplifications were performed in a final reaction volume of 25μl containing different reagents (Sigma Aldrich, Saint Louis, USA): 10x buffer solution (10 mM Tris-HCl, pH 8.3 at 25 °C, 50 mMKCl) , MgCl₂, 1.5 mM, deoxyribonucleotides (dNTPs), 200 μM, each primer, 0.4 μM (Table 1), 0.5 μ of the Taq DNA polymerase and 1 μl of extracted DNA. Amplification was performed following an initial denaturation at 95 °C for 3 min, followed by 30 cycles of 94 °C for 45s, 58 °C for 30s and 72 °C for 5 min and a final step of 72 °C for 5 min, and storage at 4 °C.

2.3.3. Visualization of Amplification Products

Visualization of the amplification products was done by electrophoresis in an agarose gel (Sigma Aldrich, Saint Louis, Canada) at 2%, in the presence of 0.5 mg / ml ethidium bromide (Sigma Aldrich, Canada). The migration was carried out at 100 volts for 45 minutes and gels were visualized under UV light. The sizes of the amplification products were estimated by comparison with a molecular weight marker (Sigma Aldrich, Saint Louis, USA) used as a standard.

2.4. Determination of Antibiotic Resistance Profile

The antibiotic resistance profile of the strains was determined using the diffusion method in agar medium according to Bauer et al. [25] and the interpretation was carried out according to the recommendations of the antibiogram committee of the French company of Microbiology [26]. Thirteen (13) antibiotics from different families were tested (Table 1). From 24-day pure colonies obtained by subculture on trypticase agar (Sigma Aldrich, Canada), a standardized 0.5 Mc Farland inoculum corresponding to 10⁸UFC/ml was prepared. From this inoculum, 100 μL were taken and added to 10 μL of physiological water (9 g NaCl + 1000L H₂O) so as to obtain a final inoculum with a concentration of 10⁶UFC/ml. This inoculum was used to inoculate Mueller Hinton agar (Sigma Adrich, canada). Antibiotic discs (Bio-Rad, Manne, France) were conventionally deposited on the surface of the agar. These include ampicillin (10 μg), amoxicillin + clavulanic acid (30 μg), cefuroxime (30 μg), cefotaxime (30 μg), astreonam (30 μg), cefepime (30 μg), chroramphenicol (30 μg), tetracycline (30 μg), nalidixic acid (30μg), ciprofloxacin (5μg), streptomycin (10 μg), gentamicin (10 μg), and cotrimozaxole (30μg). Incubation was carried out 24 hours at 37°C. The inhibition diameters around the antibiotic discs were estimated and the sensitive or resistant category interpretation was performed according to the CASFM [26]. The E. coli strain ATCC 25922 was used for the quality control of the method according to the CASFM [26]. The E. coli strain ATCC 25922 was used for the quality control of the method method according to the CASFM [26]. The E. coli strain ATCC 25922 was used for the quality control of the method.

Table 1. Primers used for confirmation of strains and detection of antibiotic resistance genes

2.5. Detection of Genetic Support for Antibiotic Resistance

For the detection of resistance genes, only strains with phenotypic resistance were taken into account. These strains were subjected to DNA extraction using the method described above and detection by PCR of resistance genes. These include genes conferring resistance to ampicillin (CITM), tetracycline (tetA, tetB), chloramphenicol (cat 1, cmlA), quinolones (qnr) and gentamicin (aaa[3]-IV). The protocol of Shahrani et al. [27] was used for this highlighting.

Amplifications were performed in a final reaction volume of 25μl containing different reagents (Sigma Aldrich, Saint Louis, USA): a 10x buffer solution (10 mM Tris-HCl, pH 8.3 at 25°C, 50 mMKCl), MgCl₂, 2.5 mM, deoxyribonucleotides (dNTPs), 200 μM, of each primer, 0.5 μM (Table 1), 0.5 μ of Taq DNA polymerase and 1 μl of extracted DNA. The amplification program consisted of initial denaturation at 95 °C for 8 min followed by 32 cycles of 94°C for 60 s, 5 °C for 70 s and 72°C for 2 min and a final stage of 72°C for 5 min followed by storage at 4 °C. After amplification, the products were visualized by agarose gel electrophoresis as described above but on an agarose gel (Invitrogen, Carlsbad, CA, USA) between 1.5% and 2% depending on the size of the gene of interest.

2.6. Statistical Analysis

Statistical analyzes were performed with the IBM SPSS statistical program for Windows version 20. Descriptive statistics were used to determine percentages of susceptibility to different antibiotics. Descriptive statistics (frequency, mean) were used for the quantitative variables.

3. Results

3.1. Confirmation of the Identification of E. coli Strains

Figure 1 shows the product of the amplification of the iudA gene of 147 bp common to all strains of E. coli and demonstrated in isolated E. coli strains of ready-to-use vegetable salads in collective Abidjan. The presence of the iudA gene was demonstrated in the 218 E. coli strains isolated

3.2. Prevalence of E. coli Resistant to Antibiotics

Among the isolated E. coli strains from ready-to-eat raw mixed vegetable salads, 70.2% showed resistance to at least one of the antibiotics tested. Resistance percentages differ depending on the type antibiotic. No resistance to cephalosporins was found, contrary to penicillin resistance, in particular ampicillin (22%) and ampicillin + clavulanic acid (2.3%). The percentages of resistance to ciprofloxacin and nalidixic acid are respectively 8.3% and 15.6%. Resistance to tetracycline was 57.3%, the highest followed by resistance to streptomycin of 38.5% (Figure 2). The prevalence of multi-resistant E. coli is 28.4%.

Figure 1. Electrophoretic profile of iudA gene amplification products in E. coli isolated from ready-to-eat raw mixed vegetable salads (M: Molecular marker of 50 bp (Sigma Aldrich, Saint Louis, USA) ; C+: Positive control E. coli ATCC 25922; Line 1, 2, 3, 4: iudA positive isolates; C-: Negative control).

Figure 2. Antibiotic resistance profile of E. coli strains

3.3. Prevalence of Antibiotic Virulence Genes in E. coli Strains Isolated

The genes CIMT (Figure 3), qnr (Figure 4) and aac [3] -IV (Figure 5) were found respectively in 14.9%, 16.7% and 100% of the ampicillin, Quinolones and gentamicin resistant strains. The tetA and tetB genes (Figure 6) were identified respectively at 6.4% and 8.8% of strains resistant to tetracycline. The genes cm1A and cat1 (Figure 7) were found in 33.3% and 20.0% of strains resistant to chloramphenicol, respectively. Table 2 shows the prevalence for each gene.

M: Molecular marker of 50 bp (Sigma Aldrich, Saint Louis, USA); Figure 3: Line 1, 2, 3, 4, 5, 6: CIMT positive isolate (462 bp); Figure 4: Line 1, 2, 3: qnrA positive isolate (670 bp); Figure 5: Line 1, 2, 3: aac[3]-IV positive isolates (286 bp); Figure 6: Line 1, 2, 3: Strains tetB positive isolates (634 bp) ; Line 4: tetA positive isolates (577 bp); Figure 7: Line 1, 2, 3: cmlA positive isolates (698 bp); Line 4, 5, 6: cat1 positive isolates (547 bp); C-: Negative control.

Figure 3. Electrophoretic profile of amplification products of the ampicillin resistance gene (CIMT)

Figure 4. Electrophoretic profile of the amplification product of quinolone resistance gene (qnrA)

Table 2. Prevalence of antibiotic resistance genes

Figure 5. Electrophoretic profile of the amplification product of the gene for resistance to gentamicin (aac[3]-IV)

Figure 6. Electrophoretic profile of the amplification product of tetracycline resistance gene (tetA, tetB)

Figure 7. Electrophoretic profile of the amplification product of tetracycline resistance gene (cmlA, cat1)

4. Discussion

In this study, 70.2% of E. coli strains isolated from vegetable salads in collective catering in Abidjan showed resistance to at least one antibiotic. The presence of antibiotic-resistant E. coli strains in ready-to-eat raw mixed vegetable salads may be due to residual strains of contamination possibly related to agricultural practices. It has been shown that vegetable growing areas use poultry manure as the main [15,28] In addition, strains of E. coli resistant to antibiotics were also found in soil, irrigation water, manure and vegetables [15,28,29,30].The presence of E. coli in ready-to-eat raw mixed vegetable salads can also be due to the poor preparation practices according to the observation made by Verraes et al. [31]. Cross-contamination in the preparation of salads by contact with strains from the manipulator or from fresh food animal origin is a factor which has already been mentioned by these authors.

The prevalence of antibiotic-resistant E. coli in vegetable salads obtained in our study is similar to those of Adeshina et al. [32] in Nigeria (75%) and Hassan et al. [33] in Saudi Arabia (76.5%). By cons, Rasheed et al. [34] in India (20%) and Holvoet et al. [35] in Belgium (11.4%) were found more reduced rates. Significant levels of presence in vegetables E. coli resistant to antibiotics have been reported previously by several authors [36,37,38,39,40].

Antibiotic resistance strains differs depending antibiotics tested, but no resistance to cephalosporins was observed in this study. The results obtained are in agreement with those of Holvoet et al. [35] and Gritli et al. [39] and differ from those of the studies by Falomir et al. [41] and Annapurna et al. [42]. In a descending order of the importance of antimicrobial resistance, the study revealed resistance to tetracycline (57.3%), streptomycin (38.5%), cotrimozaxole (26.6%) and ampicillin (22%). These results are similar to those obtained by Sheeren et al. [37] in Jordan, a resistance of 41% tetracycline and 31% cotrimozaxole but different from those of Klingbeil et al. [40] in Lebanon with higher resistance levels, estimated at 80% for tetracycline, 72.7% for cotrimozaxole, 46.7% for streptomycin and 40.4% for ampicillin. According to Holvoet et al. [35], tetracycline resistance is alarming in developing countries and may reflect contamination of raw vegetables by irrigation water or contaminated manure.

Furthermore, these resistances can be potentially acquired by the food chain from human contamination that have adapted to therapeutic practices [43,44]. Low resistances in gentamycin (2.3%) and chloramphenicol (6.9%) were similar to those of Campos et al. [38] in Portugal (Chloramphenicol: 3%), Gritli et al. [39] in Tunisia (Gentamicin and chloramphenicol: 7.4%), Hasan et al. [33] in Saudi Arabia (Gentamicin: 4.7%) and Benzason et al. [45] in Portugal (Gentamicin: 2.5%). In contrast with our results and those previously mentioned, no resistance to gentamicin was observed in Bangladesh [38,46]. Resistance to nalidixic acid and ciprofloxacin was found to be 15.6% and 8.3%, respectively. Campos et al. [38] noted in their study resistance levels of 5% for ciprofloxacin and 36% for nalidixic acid. However, other authors found no resistance to ciprofloxacin [38,39,41,46]. According to Hasan et al. [33] resistance to fluoroquinolones, gentamicin and cephalosporins suggests sources of animal or human contamination because these classes are not used in vegetable farming, or plant-associated bacteria by horizontal transfer can also be assumed.

In this study, 24.6% of E. coli strains were found to be resistant to at least three families of antibiotics. Bacteria resistant to at least three families of antibiotics are referred to as Multi Resistant Bacteria (BMR) [47].This result is in agreement with those of Shereen et al. [37] (27.8%) in Jordan (27.8%), Nipa et al. [36] in Bangladesh (33.3%) and Odu et al. [48] in Nigeria (33%) and contrary to those obtained by Klingbeil et al. [37] in Lebanon and Adeshina et al. [32] in Nigeria (75%).

This study highlighted one of the genetic supports for antibiotic resistance in E. coli strains isolated from ready-to-eat raw mixed vegetable salads. Indeed, the presence of resistance genes to tetracycline (tetA, tetB), quinolones (Qnr), ampicillin (CIMT, gentamicin (aaa [3] -IV) and chloramphenicol (cmlA, caat1) have been highlighted. This result is consistent with studies carried out in Portugal by Campos et al., [38] Shakerian et al. [49] in Iran, Kim et al. [50] in Korea where tetA, tetB, catA, aaa[3]-IV, CIMT genes have also been demonstrated in E. coli strains isolated from vegetable salads. Sheeren et al. [37] also reported tetracycline resistance to the presence of tetA (64.7%) and tetB (5.9%) genes in E. coli strains from vegetables in Jordan. According to these authors, the rapid diffusion of tetracycline resistance genes to bacteria is due to the localization of the tetA gene on plasmids, transposons and integrons [51]. Also the tetA and tetB genes are usually found and maintained in soil and water for a long time [52]. In our study, quinolone resistance was associated with the presence of qnr gene to a percentage of 16.7%. This result is similar to other studies conducted in Côte d'Ivoire [5,17,19], which demonstrated the presence of qnr gene in strains enterobacteria of human, animal and environmental origins.

At present, multi resistance is frequently observed in E. coli isolates from human clinical cases worldwide, and this characteristic has an increasing impact on the treatment of community E. coli infections [53,54]. Previous studies have reported that E. coli isolates from animals and foodstuffs have determinants of resistance to many classes of antimicrobial agents constuting an important reservoir for transmissible resistance genes [55]. These resistant bacteria may enter the food chain, which is a food safety problem because they can transfer resistance genes to opportunistic pathogens [56,57].

5. Conclusion

This study shows that ready-to-eat raw mixed vegetable salads consumed in collective catering in Abidjan are contaminated with multi-resistant strains of E. coli. In some cases, this resistance is carried by resistance genes assuming a horizontal transfer of resistance to pathogenic bacteria. Vegetable salads can be used as a vehicle for the transfer of multi-resistant bacteria. Adequate hygiene measures should be taken when preparing to preserve the health of the consumer.

Acknowledgments

The authors thank to the National Laboratory Public Health of Abidjan (Côte d’Ivoire) and the biotechnology Laboratory of CTSS in Moncton University (Canada). The authors thank also to the Ministere de l’enseignement superieur et la recherche scientifique of Cote d’Ivoire through the scholarship received for the realization of this project.

Conflict of Interest

The authors declare no conflict of interest associated with this work.

References

[1]   | World Health Organization (WHO). Antimicrobial resistance: 2016. [online] Available: http://www.who.int/mediacentre/factsheets/fs194/en/ [Accessed Dec. 24, 2016].
[2]   | Centre for Disease Control and Prevention, US (CDC). Antibiotic resistance threats in the United States. 114p. 2013. [online]. Available http://www.cdc.gov/drugresistance/threat-report-2013/ [Accessed Dec. 24, 2016].

[3]  
European Centre for Disease Preventionand Control (ECDC) and European Medecines Agency (EMEA), 2009. The bacterial challenge: time to react. ECDC, 2009, rapport, 54 p. [online]. Available: http://ecdc.europa.eu/en/publications/Publications/0909_TER_The_Bacterial_Challenge_Time_to_React.pdf . [Accessed Jan. 20, 2016].

[4]   | World Health Organization. Antimicrobial resistance: global report on surveillance. World Health Organization, Geneva, Switzerland. 2014. [online]. Available: http://www.who.int/drugresistance/documents/surveillancereport/en/ [Accessed Dec. 24, 2016].
[5]   | Guessennd, K.N., Résistance aux antibiotiques en Afrique. 2013. [Online]. Available:http://www.assitebbiorif.com/fr/2a7_resistance_en_afrique_brazzaville.pdf [Accessed Jan. 22, 2017].
[6]   | Ouattara, N.D., Boby, B., Guessennd, N., Guinan, J.C., Dosso, M., Rôle du laboratoire dans la surveillance des bactéries multi-résistantes d’origine infectieuses en côte d’ivoire de 2007 à 2011, Rev. Bio-Africa. 11: 35-42, 2013.
[7]   | Bonny, C.C., Méité, S., N’douba, K.A., Koffi, P., Faye-Ketté, H., Dosso, M., Colonization of catheters by bacterial in the intense care unit in Abidjan, SJM. 1: 38-42, 2011.
[8]   | Moro, A.J.L., Résistance bactérienne et phytomolécules antimicrobiennes issues de Morinda morindoides. Thèse de Doctorat, Université de Bretagne occidentale, France, 2013.
[9]   | Adele K.N., Drug resistance bacterial isolates in inpatients at Cocody University Hospital, Abidjan; Côte d’Ivoire in 2014. Antimicrob Resist Infect Control., 4:167, 2015.
[10]   | Goualie, G.B., Akpa, E.E., Kalou-N’Gazoa, E.S., Guessennd, N., Bakayoko, S., Niamké, L.S., Dosso, M., Prevalence and antimicrobial resistance of Thermophilic Campylobacter isolated from chicken in Côte d’Ivoire, Int J Food Microbiol. ID 150612, P 5. 2012.
[11]   | Koffi, A.R., Dadie, A., Ouassa, T., Karou, T., Dje, K.M., Menan, E.I.H., Serotypes and antibiotic resistance of Salmonella spp. isolated from poultry carcass and raw gizzard sold in markets and catering in Abidjan, Côte d'Ivoire, Int. J. Curr. Microbiol. App.Sci., 3: 764-772, 2014.
[12]   | Bonny, A.C., Karou, T.G., Ake, M.D.F., Dadié, A.T., Bohoua, L.G., Niamké, S.L., Distribution of serovars and antibiotic resistance genes of Salmonella isolated from chicken gizzards in Abidjan, Côte d’Ivoire, ‎IJIAS, 11: 567-578, 2015.
[13]   | Dadié, A.T, Guessennd, N., Tiekoura, B., Faye-Kette, H., Dosso, M., Résistance aux bêta- lactamines d’Escherichia coli d’origine alimentaire et humaine isolés à Abidjan, J. Sci. Pharma. Biol, 4: 62-69, 2003.
[14]   | Coulibaly, K.J., Gadji, A.A.G., Kouadio, K.., Koffi, K.S., Yapo, O.B., Dosso, M., The antibiotic resisting profile of Salmonella isolated from the sewage of the campus of the University of Cocody, Abidjan, Cöte d’Ivoire, Int. J. Trop. Dis. Health, 4: 608-620, 2014.
[15]   | Koffi-Nevry, R., Assi-Clair, B.J., Koussémon, M., Wognin, A.S., Coulibaly, N., Potential enterobacteria risk factors associated with contamination of lettuce (Lactuca sativa) grown in the peri-urban area of Abidjan (Côte d’Ivoire), IJBCS. 5: 279-290, 2011.
[16]   | Wognin, S,. Facteurs de risques de contamination et gènes de virulences associés à Escherichia coli dans l’environnement maraîcher: cas de la laitue (Lactuca sativa) en zone péri-urbaine d’Abidjan, Thèse de doctorat, Université NanguiAbrogoua, Abidjan, Côte d’Ivoire, 2014.

[17]  
Albrechtova, K., Papousek, I., De Nys, H., Pauly, M., Anoh, E., Low Rates of Antimicrobial-Resistant Enterobacteriaceae in Wildlife in Ta ̈ı National Park, Côte d’Ivoire, Surrounded by Villages with High Prevalence of Multiresistant ESBL-Producing Escherichia coli in People and Domestic Animals, PLoS ONE. 9(12): e113548. 2014.

[18]   | Guessennd, N., Kacou-N’douba, A., Gbonon, V., Yapi, D., Ekaza, E., Dosso, M. and Courvalin, P., Prévalence et profil de résistance des Entérobactéries productrices de beta lactamases a spectre élargi (BLSE) à Abidjan côte d’ivoire de 2005 à 2006, J. sci. pharm. Biol, 9: 63-70, 2008.

[19]  
Baguy, O.M., Guessennd, K.N., Coulibaly, N.D., Saraka, N.D., Coulibaly, K.J., Koffi-Nevry, R., Ouattara, G.D., Gbonon, V., Tiekoura, K.B. and Dosso M., First report of Qnr genes in multidrugs resistant (ESBL) Enterobacteria isolated from different ecosystems in Abidjan, Ivory Coast, IJBSA, 1: 170-175, 2014.

[20]   | Russo, T.A. and Johnson J.R., Medical and economic impact of extra intestinal infections due to Escherichia coli: focus on an increasingly important endemic problem. Microbes Infect., 5: 449-456, 2003.
[21]   | Johnson J.R. and Russo T.A., Uropathogenic Escherichia coli as Agents of diverse non‐urinary tract extraintestinal infections. J. Infect. Dis., 186: 859‐864, 2002.

[22]  
Frank, C., Werber, D., Jakob, P., Cramer A.M., Faber, M., Heiden, M.D., Bernard, H., Fruth, A., Prager, R., Spode, A., Wadl M., Zoufaly, A., Jordan, S., Kemper, M.J. and Follin P., Epidemic Profile of Shiga-Toxin-Producing Escherichia coli O104:H4 Outbreak in Germany. New Engl. J. Med., 365: 1771-1780, 2011.

[23]   | Le Minor, L., Richard, C., Méthodes de laboratoire pour l’identification des Entérobactéries. Commission des laboratoires de références et d’expertise de l’institut Pasteur, Institut Pasteur, Paris, France. 218 p. 1993.
[24]   | Maheux, A.F., Picard, F.J., Boissinot, M., Bissonnette, L., Paradis, S., Bergeron, M.G., Analytical comparaison of nine PCR primer set designed to detect the presence of Escherichia coli/Shigella in water samples, Water. Res, 43: 3019-3028, 2009.
[25]   | Bauer, A.W., Kirby, W.M., Sherris, J.C., Turck, M., Antibiotic susceptibility testing by a standardized single disk method, Am. J. Clin. Pathol., 45: 493-496, 1966.
[26]   | Comité de l’Antibiogramme de la Société Française de Microbiologie (CA-SFM), Recommandation 2014. [Online]. Available:http://www.sfmmicrobiologie.org/UserFiles/files/casfm/CASFM_EUCAST_V1_0_2014(1).pdf [Accessed Jan. 20, 2017].
[27]   | Shahrani, M., Dehkordi, S.F., Momtaz, H., Characterization of Escherichia coli virulence genes, pathotypes and antibiotic resistance properties in diarrheic calves in Iran, Biol. Res., 47: 28. 2014.
[28]   | Koffi-Nevry, R., Assi-Clair, B.J., Assemand, E.F., Wognin, A.S., Koussemon, M., Origine des témoins de contamination fécale de l’eau d’arrosage de la laitue (lactuca sativa) cultivée dans la zone péri urbaine d’Abidjan, J. Appl. Biosci., 52: 3669-3675, 2012.
[29]   | Sackou, K.J., Claon, J.S., Oga, A.S., Aguessi, K.T., Lorougnon, D., Diby, Y. and Kouadio, K.I., Qualité sanitaire des laitues cultivées à Abidjan, Microbiol. Hyg. Alim., 52: 48-50, 2006.

[30]  
Adiko, A., Matthys, B., Cissé, G., Bonfoh, B., Tanner, M., Utzinger, J., Relation entre le capital humain des maraîchers urbains et leurs comportements de prévention des risques sanitaires sur les sites de culture à Abidjan (Côte d'Ivoire). VertigO-la revue électronique en sciences de l'environnement [Online]. 2010. Available: http://vertigo.revues.org/10088. [Accessed April 12, 2016].

[31]  
Verraes, C., Sigrid, V.B., Eva, V.M., Els, V.C., Patrick., Boudewijn, C., Marie-Athénaïs, S., Xavier, V.H., Hein, I., Katelijne, D., George, D., Claude, S., Jan, D. B., Jeroen, D., Lieve, H., Antimicrobial Resistance in the Food Chain, A Review. Int. J. Environ. Res. Public Health., 10: 2643-2669, 2013.

[32]   | Adeshina, G.O., Jibo, S.D., Agu, V.E., Antibacterial Susceptibility Pattern of Pathogenic Bacteria Isolates from Vegetable Salad Sold in Restaurants in Zaria, Nigeria, J. Microbiol. Res., 2(2): 5-11, 2012.
[33]   | Hassan, S.A., Altalhi, A.D., Gherbawy, Y.A., El-Deeb, B.A., Bacterial Load of Fresh Vegetables and Their Resistance to the Currently Used Antibiotics in Saudi Arabia, Foodborne. Pathog. Dis., 8: 1011-1018, 2011.
[34]   | Rasheed, M.U., Thajuddin, N., Ahamed, P., Teklemariam, Z., Jamil, K.., Antimicrobial drug resistance in strains of Escherichia coli isolated from food sources, Rev. Inst. Med. Trop. sao Paulo.,56: 341-346, 2014.
[35]   | Holvoet, K., Sampers, I., Callens, B., Dewulf, J., Uyttendaelea, M., Moderate Prevalence of Antimicrobial Resistance in Escherichia coli Isolates from lettuce, Irrigation water and Soil, A.S.M, 79: 6677-6683, 2016.
[36]   | Nipa, M.N., Mazumdar, R.M., Hasan, M.D., Fakruddin, MD., Islam, S., Bhuiyan, H.R., Iqbal, A., Prevalence of Multi Drug Resistant Bacteria on Raw Salad Vegetables Sold in Major Markets of Chittagong City, Bangladesh, Middle East. J. Sci. Res., 10: 70-77, 2011.
[37]   | Shereen, Z.B., Asem, A.S., Fresh leafy green vegetables associated with multidrug resistant E. coli, IAJAA,;(2):3. 2013.
[38]   | Campos, J., Mourão, J., Pestana, N., Peixe, L., Novais, C., Antunes, P., Microbiological quality of ready-to-eat salads: An underestimated vehicle of bacteria and clinically relevant antibiotic resistance genes, Int. J. Food. Microbiol., 166: 464-470, 2013.
[39]   | Gritli, A., Ibelkahla, I., Moussa, M.B., Abassi, M.S., Occurrence and characterization of Escherichia coli in raw lettuce consumed in a military hospital, JS-INAT, 11: 899-907, 2015.
[40]   | Klingbeil, D.F., Kuri1, V., Fadlallah, S., Matar, G.M., Prevalence of antimicrobial-resistant Escherichia coli from raw vegetables in Lebanon, J. Infect. Dev. Ctries. 10: 354-362, 2016.
[41]   | Falomir, M.P., Gozalboand, D., Hico, H., Coliform bacteria in fresh vegetables from cultivated lands to consumers. University of Valencia, Spain, JFAE, 1175-1181. A. Méndez-Vilas (Ed.), 2010.
[42]   | Annapurna, Y.V.S., Savan,t R., Multi drug resistance and mar index among bacteria associated with fruits and vegetables, Int. J. Biopharm. Res., 3: 182-185, 2014.
[43]   | Manges, A.R., Johnson, J.R,. Food-borne origins of Escherichia coli causingextraintestinal infections, Clin. Infect. Dis., 55: 712-719, 2012.
[44]   | Nordstrom, L., Liu, C.M., Price, L.B., Foodborne urinary tract infections: a new paradigm for antimicrobial-resistant foodborne illness, Front. Microbiol., 4:29, 2013.
[45]   | Benzason, G.S., MacInnis, R., Potter, G., Hughes, T., Presence and potential forhorizontal transfer of antibiotic resistance in oxidase-positive bacteria populating raw salad vegetables, Int. J. Food Microbiol., 30: 3-42, 2008.
[46]   | Nawas, T., Mazumdar, R.M., Das, S., Nipa, M.N., Islam, S., Bhuiyan, H.R., Ahmad, I., Microbiological Quality and Antibiogram of E. coli, Salmonella and Vibrio of salad and water from restaurants of Chittagong, J. Environ. Sci. & Natural Resource, 5: 159-166, 2012.

[47]  
Magiorakos, A.P., Srinivasan, A., Carey, R.B., Carmeli, Y., Falaga,s M.E., Giske, C.G., Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance, Clin. Microbiol. Infect., 18: 268-81, 2012.

[48]   | Odu, S., Andy, I., Umo, A., Ekpo, M., Potential human pathogens (bacteria) and their antibiogram in ready- to- eat salads sold in Calabar, South-south, Nigeria, J. Trop. Med., 5: 1-5, 2008.
[49]   | Shakerian, A., Rahimi, E., Emad, P., Vegetables and restaurant salads as a reservoir for shigatoxinogenic Escherichia coli: Distribution of virulence factors, O-serogroups and antibiotics properties, Prot., 79: 1154-60, 2016.
[50]   | Kim, S., Woo, G.J., Prevalence and characterization of antimicrobial-resistant Escherichia coli isoled from conventional and organic vegetables, Foodborne. Pathog. Dis., 11: 815-21, 2014.
[51]   | Sengeløv, G., Agresø, Y., Halling-Sørensen, B., Baloda, SB., Andersen, J. and Jensen, LB., Bacterial antibiotic resistance levels in Danish farmland as a result of treatment with pig manure slurry, Environ. Int., 2: 587-595, 2003.
[52]   | Börjessonz, S., Mattsson, A., Lindgren, P., Genes encoding tetracycline resistance in a full-scale municipal wastewater treatment plant investigated during one year, J. Water. Health, 8: 247-256, 2010.
[53]   | Yükse,l S., Oztürk, B., Kavaz, A., Ozçakar, Z.B., Acar, B., Güriz, H., Aysev, D., Ekim, M. and Yalçinkaya, F., Antibiotic resistance of urinary tract pathogens and evaluation of empirical treatment in Turkish children with urinary tract infections, Int. J. Antimicrob. Agents, 28: 413-416, 2011.
[54]   | Asem, A., Shehabi, A., Haider, M., Fayyad., K., Frequency of antimicrobial resistance markers among Pseudomonas aeruginosa and Escherichia coli isolates from municipal sewage effluent water and patients in Jordan, IAJAA, 11: 1-5, 2011.
[55]   | Eáenz, Y., Brias, L., Domínguez, E., Ruiz, J., Zarazaga, M., Vila, J., Torres, C., Mechanisms of resistance in multiple-antibiotic-resistant Escherichia coli strains of human, animal, and food origins, Antimicrob. Agents Chemother, 48: 399-4001, 2014.
[56]   | Sunde, M., Prevalence and characterization of class 1 and class 2 integrons in Escherichia coli isolated from meat and meat products of Norwegian origin, J. Antimicrob. Chemother, 56: 101-1024, 2005.

[57]  
Slama, K., Jouini, A., Sallem, R., Somalo, S., Sáenz, Y., Estepa, V., Boudabous, A., Torres, C., Prevalence of broad-spectrum cephalosporin-resistant Escherichia coli isolates in food samples in Tunisia, and characterization of integrons an antimicrobial resistance mechanisms implicated, Int. J. Food. Microbiol., 137: 28-286, 2010.