Antimicrobial Susceptibility of Community Acquired Escherichia coli in Urinary Tract Infections (UTI) in Benin for Eleven Years (2005-2015)

National Laboratory Fighting Against AIDS, National Direction of Health, Health Ministry, 04PO Box 378 Cotonou, Benin Department of Human Biology, Research Laboratory in Applied Biology, Polytechnic, School of Abomey-Calavi, University of Abomey-Calavi, 01 PO Box 2009, Cotonou, Benin Department of Medecine, Internal Medicine Service of Hospital Center, University Parakou, PO Box: 02 Parakou, Bénin Department of Medecine Laboratory of Bacteriology and Virology, University Cheikh Anta Diop, PO Box 7325, 30 Avenue Pasteur, Dakar, Senegal Department of Pharmacy, Drugs and Diagnostic Investigation, National Laboratory of Health Ministry, 04 PO Box 378, Cotonou, Bénin Department of Medecine, National Laboratory Fighting Against Tuberculosis, 01 PO Box 321 Cotonou, Benin Department of Medecine, Medical Analysis Laboratory of Pediatric, University Hospital Charles De Gaule of Ouagadougou, Burkina Faso Department of Medecine, National Hepato-Virology Institute, Medicine Faculty of Mauritanie, Mauritanie Department of Medecin, National Laboratory Fighting Against Tuberculosis; 01 POBox 321 Cotonou, Benin


Introduction
Antimicrobial resistance had become a growing public health problem in the world and E. coli appeared as one of nine bacteria commonly causing infections in community and hospitals (WHO, 2014). Worldwide, E. coli remains the most encountered pathogen among those implicated in community acquired urinary tract infection (Jean-Marie et al., 2007). With (46.4-74.2%) of global representation (Inês et al., 2013), it's the first DOI: 10.3844/ajidsp.2017.21.27 22 strains isolated in children between 2 to 5 years of age followed by Klebsiella, Proteus and Pseudomonas (Rajiv et al., 2013). In a recent study done in 2012 at Ngaoundere in Cameroon focused on community acquired infection, Carine et al. (2012) found that 66.7% of E. coli was mostly Extended-spectrum betalactamase producers in the samples of stools. It is well known the proximity between anal cavity and urinary tract in women. Urinary Tract Infections (UTI) is the most commonly diagnosed infections in communities which are often treated with different antibiotics. Some studies have reported an increasing resistance rate to antibiotics such as amoxicillin, amino penicillin, trimetropimsulfamethoxazole and others reducing therapeutic possibilities (Gupta et al., 1999;Kahlmeter, 2003a).
A study conducted in Benin have shown, that the beta lactam antibiotics were the most prescribed and represented 44.4% of prescriptions, followed, in order of imidazole, quinolones, aminoglycosides, sulfonamides, macrolides and related, cyclins and phenicol (Dissou et al., 2009) The Fig. 1 shows the susceptibility rates of E. coli for aminoglycosides, tetracycline, phenicol, quinolones, sulfonamides+associations, penicillin, cephalosporin, aztreonam and nitrofurantoin.
Regarding aminoglycosides, we observed susceptibility increase of E. coli to netilmicin (10 µg) (80 to 100%) on three use years. During the 11 study years, the maximum susceptibility rate to gentamycin (30 µg) was 93.3%.
Among phenicol, chloramphenicol (30 µg) was one used during the first ten years. E. coli susceptibility to this drug varied between (38 to 70%) until 2014.
Aztreonam (30 ug) tested during six years showed 100% rate effectiveness to E. coli. Following a decrease in 2008, a continuous increase in susceptibility rates was observed until 2010 (100%).

Discussion
E. coli appeared as the most frequent bacteria in UTI representing 38.3% (563/1470) of all isolated bacteria and 58.5% (563/963) of enterobacteriaceae. The second major finding in our study was E. coli susceptibility to antibiotics.
In Benin, UTI were major causes of antibiotics prescribing among adults and adolescences (Dissou et al., 2009). The lack of national recommandations involve their bad utilization (Dissou et al., 2009). In fact, Benin is West Africa country where a lot of counterfeit drug are circulating. A Pharmaceutical desposit drug is in Cotonou at Dantokpa market. Thus, the population supply drug and taking care by self-medication. In addition, due to their results quality, the NL received widely patients for uroculture analyzes. This should explain the 32.6% rate positive uroculture observed in this study. This rate was two fold higher that observed in Senegal (Diop-Ndiaye et al., 2014) and Portugal (Inês et al., 2013). The major bacteria isolated in those studies was E. coli as in our study (38.3%) which the virulence factors are specific properties. Those specificity confer on the bacterium the ability to adhere to the urinary tract and invade the host tissues causing injury (Moura et al., 2009). This study shows a proportion of E. coli (38.3%, 563/1470), significantly lower than that observed by Nisel et al. (2016) (67%, 8975/13281).
As for tetracycline, from 2007 year, the resistance rate around 76%. The loss effectiveness was very alarming and this antibiotic should not be prescribed against UTI. At Pakistan, a similar resistance rate of E. coli to tetracyclin was observed in 70% (Ahmad et al., 2015). Minocyclin in the first three years showed effectiveness around 30% while a study conducted in China reported 92.1% of susceptibility by (Haihong et al., 2015).
The maximum efficacy rate of chloramphenicol to E. coli was 60%. Behailu et al. (2016) reported in Dil Chora Referral Hospital, Dire Dawa, Eastern Ethiopia an effectiveness rate of 77.8% in study conducted among pregnant women attending at antenatal clinic (Behailu et al., 2016).
Over 11 year, nalidixic acid had maximum efficacy rate at 75%. This rate was lower than observed at Bangui (90%) (Hadiza et al., 2003). However, none difference has been observed between the rate that of Dakar (76.1%) (p = 0.889) (Jean-Marie et al., 2007). This antibiotic was the first among quinolone used only for the therapy of gram-negative UTI, because it has ability to penetrate the tissues (Moura et al., 2009). Of high susceptibility until 2010, the loss effectiveness of ciprofloxacin should be explain by its large use. In fact, ciprofloxacin can be used in UTI patients with allergies to others drug or in old age patients with recurrent infections and in diabetics (Eom et al., 2002;Schilling et al., 2002;Killgore et al., 2004). Nevertheless, the 75% susceptibility rate of E. coli observed in 2015 was not significant (p = 0.811) that observed in Dakar (Jean-Marie et al., 2007).
Until 2011, forty percent of E. coli were susceptibility to TMP-SMX. This antibiotic was also called co-trimoxazole. Some variable susceptibility rates were observed in several studies: (70.9-71.8%) in Northern Israel (Wasseem et al., 2007), 31.9 and40% at Dakar (Jean-Marie et al., 2007;Diop-Ndiaye et al., 2014), 15% in Bangui (Hadiza et al., 2003), 35% to Pakistan (Ahmad et al., 2015). TMP-SMX resistance rates of 25-68% were also reported in others countries (Urbina et al., 1989;Wylie and Koornhof, 1989). After 2011 year, a total loss of effectiveness was observed with this antibiotic, that should be explained by its no medically in use through its supply by the people in the market.
The effectiveness rates of ampicillin and amoxicillin in our study were 33% and 25% respectively. Primarily, resistance to these antibiotics by β-lactamase producing E. coli come from their sub-inhibitory concentrations (Moura et al., 2009). Concerning amoxicillin, some studies conducted at Dakar have shown similar rates as in our study (Jean-Marie et al., 2007;Diop-Ndiaye et al., 2014). As for ampicillin, the study investigated the prevalence of antibiotic resistance in urinary tract infections caused by E. coli in children showed 53.4% of resistance rate (Ashley et al., 2016) while 67% has been reported in our study and Turkey (Nisel et al., 2016). Of all cases observed in 16 countries in Europe plus Canada, the E. coli resistance to ampicillin was 30% (Kahlmeter, 2003b).
The amoxicillin/clavulanic acid activity depends on the level of β-lactamase production by E. coli. In our study, it efficacy rate was 82% during all study period, more one fold higher that reported (59.3%) by (Alemu et al., 2012). An opposite, Sharan reported 88% of resistance among children less of 5 years in India (Rajiv et al., 2013).
A resistance rate of 86% of E. coli to carbenicillin was observed in our study, similar that reported (100%) on children diarrhea and swim areas on Tigris River in Baghdad city (Israa et al., 2014).
Cephalosporins activity against E. coli has increased from first to fourth generation and the new classes were too much. Recently, the number of resistant strains to cephalosporins has increased (Ribeiro et al., 2002). In our study, four antibiotics of this class were tested. Cefotaxim and ceftriaxon showed effectiveness to 100% during use years. Our results were similar those observed at Dakar (97%) and Northern Israel (98%) for each antibiotic respectively (Jean-Marie et al., 2007;Urbina et al., 1989). In contrary, Sharan reported a high resistance for both antibiotics (73.5% and 73.5%) among children less of 5 years in India (Rajiv et al., 2013). For cephalosporin for three years, a 50% susceptibility rate was reported in our study. Wasseem et al (2007) reported effective rate of cephalothin to E. coli ranging between (60%-74%) in Northern Israel. About cephalexin, a high resistance rate of 80% of this antibiotic to E. coli was observed as reported by Datta in India (Datta et al., 2004).
Severe UTI requires appropriate antimicrobial treatment preferably cephalosporins (third generation). But, in patients with an allergy to cephalosporins, aztreonam may be used (Grabe et al., 2015). Our study showed effectiveness of aztreonam to E. coli at 100%. This effectiveness was already seen since 2005 with 67% rate. In India, Iraj et al. (2015) reported 56.7% of susceptibility rate among children less than 12 years.
As for nitrofurantoin, a high effectiveness (100%) observed in our study was similar that observed in Portugal (94%) (Inês et al., 2013) and india (100%) (Rajiv et al., 2013). In several studies, nitrofurantoin resistance rates remained at lower levels (Arman et al., 2012;Kahlmeter and Poulsen, 2012;Nisel et al., 2016). The lower rate (1.3%) was reported equally in study performed among children used antibiotics in primary care by (Ashley et al., 2016). Because their therapy efficacy has been demonstrated clinically and microbioligically (69% and 68%) success respectively (Işıkgöz et al., 2012), nitrofuratoïn should be recommended for ambulantory treatment and the cystitis and pyelonephritis treatment in women even pregnancy (Kalpana et al., 2011). It is a good alternative for uncomplicated UTI treatment when it is dispensed at appropriate dosages and suitable time intervals (Nisel et al., 2016).
Based on our above results mentioned, E. coli susceptibility decreased until 33% for ampicillin, 30% for minocyclin, 24% for tetracyclin and 25% for amoxicillin and fallen to 14% for carbenicillin, 0% in 2015 for TMP-SMX, remains around 75% for ciprofloxacin, while cephalosporin third generation, aztreonam and nitrofurantoin were maintained their effectiveness rate until 100%.
These results are important in medical practice in Benin. We have confirmed now that ampicillin, minocyclin, tetracyclin, amoxicillin, carbenicillin and TMP-SMX couldn't be appropriated for treatment of UTI and that use of quinolone could exposed to resistance in 25% of cases and that third-generation cephalosporin, aztreonam and nitrofurantoïn are those that offers the highest effectiveness of UTI treatment.
One limitation of this study is the low number of patients per year that did not allow a comparative analysis of the resistance of E. coli during the 11 years of study.

Conclusion
The use of drugs such as minocyclin, ampicillin, amoxicillin, carbenicillin, cephalothin, cephalexin and trimethoprim/sulfamethoxazole does not seem appropriate for empirical treatment of UTI. These findings highlighted the importance in Benin to implement national guideline of antibiotics use and done toward medic and nurse training.