**4. Discussion**

The emergence and spread of multidrug-resistant (MDR) bacteria are major public health threats worldwide. Particularly, DEC that produce ESBL are of great concern, because their resistance to penicillins and narrow extended-spectrum cephalosporins reduces considerably the treatment options. The prevalence of ESBL in *Enterobacteriaceae* has been detected at local levels in various African countries; moreover, a study was conducted in 2014 on the prevalence of ESBL and what type of genes are involved in its occurrence [24]. The frequency of ESBL-producing *E. coli* was 67.7% in our study. Similar prevalence was reported in Egypt (69.6%) [25] and Palestine (66.7%) [26]. Nevertheless, our prevalence was higher than those in Burkina Faso (58%) [6], Iran (40.8%) [27], Saudi Arabia (30.6%) [28], Japan (20.4%) [29], Colombia (11.7%) [30], and Nepal (22.7%) [31]. Otherwise, our result is lower than the ESBL production in clinical isolates of *E. coli* reported somewhere else in Iran [32]. The prevalence of ESBL resistance in *E. coli* isolates in European countries is reported to be around 3.9% with variations between countries [33]. Overall, these percentages are lower than those found in middle-income countries like Thailand (71.25%) [34] and China (50.5%) [35]. This difference between ESBLs' prevalence might be due to patient's age, the type of samples, and the country health facilities in the management of diarrheal infections regarding antibiotics use. Indeed, in developing countries, most patients received antibiotics treatment without prescription [36, 37]; such common practices in nearly all developing countries cause a selective pressure on *E. coli*, whereas in more developed countries effective strategies for the control of antimicrobial are present, which effectively prevents the emergence of ESBLs [36].

It has been reported that bacteria such as *E. coli* and *K. pneumoniae* are major ESBL producers resulting in serious threat to the treatment regimen [38]. Indeed, ESBL enzymes are becoming increasingly expressed by many strains of pathogenic bacteria presenting diagnostic challenges to the clinical microbiology laboratories [39, 40]. Until recently, antimicrobial therapy has played an important role in the treatment of human bacterial infections. However, the drug resistance has emerged in the treatment of bacterial infections due to ESBL enzymes [39]. Indeed, these enzymes can degrade all β-lactam antibiotics leading to multidrug-resistant bacteria. Therefore, reporting of ESBL-producing isolates from clinical samples is critical for the clinicians. It constitutes the guidelines to select appropriate antibiotics for the treatment, including to take proper precaution to prevent the spread of these resistant organisms to other patients [31].

The present study shows 19 ESBLs genes (90.5%) out of the 21 ESBLs-producing *E. coli*. Analysis of the ESBL-encoding genes indicated that the majority of the ESBL-positive isolates harbored *bla*OXA (38.7%), followed by *bla*SHV (19.4%), *bla*CTX-M (9.7%), and *bla*TEM (6.5%). The emergence of β-lactam resistance in *Enterobacteriaceae* is related primarily to the production of enzymes such as TEM and SHV variant, which were the most common ESBLs during the past decade. However, OXA and CTX-M β-lactamases have emerged as prevalent ESBL worldwide type compared with the TEM and SHV genotypes [41].

In the present study, OXA-type ESBL-producing DEC strains (38.7%) were the most frequently detected ESBL gene. This prevalence is lower than that reported in our previous study in rural area of Burkina Faso: 100% [9], also lower comparatively to 52% reported in Pakistan [42]. However, a recent study in young children reported 3% of commensal *E. coli* bearing the *bla*OXA gene in Bangladesh [41]. Thus, it appears that the emergence of ESBLs-producing bacteria among gut bacteria of young children can transfer resistance and related genes horizontally across pathogenic *E. coli*, and commensal *E. coli* leading to a public health concern. Most of the OXA-type ESBL-producing *E. coli* isolates (29%) in our study were detected from the Paul VI hospital (*p* = 0.002). This hospital is located in peripheral area
