RESISTANCE PATTERNS OF MULTI-DRUG RESISTANT ESCHERICHIA COLI CAUSING URINARY TRACT INFECTION

480 mid-stream urine samples were collected from outpatients and inpatients attending Tobruk Medical Center. 300 samples gave positive culture, 162 of these were Escherichia coli. The strains sensitivity to 14 antibiotics was tested. High incidence of resistant strains, high degree of association between resistance and complex resistance patterns of the same strains is seen. The strains were resistant to Ampicillin, Penicillin, Erythromycin, Cephalexin and Sulfamethoxazole with 91.9%, 90.7%, 82.7%, 76.5% and 57.4% respectively. The strains were sensitive to Neomycin, Oxacillin and Nitrofurtoin with 100%, 99% and 83% respectively. A symmetrical result for all strains resistance to indicated pairs of drugs were obtained. Strong association between most antibiotic occurred.


Introduction
The large intestine constitutes the main source of E.coli, which is the principle cause of variety infections including urinary tract infection. Urinary Tract Infection (UTI) is one of the most distributed bacterial infection in many developing countries where good sanitation is not maintained Tanzina et al., (2016). It has been reported that up to 15 million person are infected each year worldwide Stam and Norrby, (2001). Antimicrobial resistance has been considered as rising risk both in developed and developing countries (Pfaller;2000). This risk could be sever in developing countries, where there is no strict information program concerning the use of antibiotics (Jigna and Pratibha, 2012). There are world wide data show that there is increasing resistance among UTI causative agents to the most common prescribed antibiotics, and resistance has emerged even to newest and most efficient antibiotics (Taneja et al., 2008).
The most important antibiotic resistance risks are reported in Enterobacteraceae for all major antigram negative agents such as beta-lactam, fluoroquinolones and aminoglycosides (Osterblat et al., 2000).
Multidrug resistance in E.coli is of particular concern because it is the most common gramnegative pathogen causing many infections including UTI. In addition, resistant E.coli strains have the ability to exchange antibiotics resistance factor (R-Factor) to other strains of E.coli but also to other gram-negative pathogens (Jiana and Pratibha, 2012).
Because now day ' s antibiotics resistance has become an important phenomenon due to widespread use of antibiotics by patient without testing antibiogram (Tanziaet al., 2016).
It is obligatory to have knowledge about the organisms causing UTI and there susceptibility to antibiotics. Therefore, the purpose of this study to isolate, and identify E.coli strains from urine samples and determine their susceptibility to common available antibiotics which may help the physician to choose the right treatment for the prevention of UTI.

Materials and Methods
Mid-stream urine samples were collected from 480 inpatients and outpatients having symptom suggestive of urinary tract infection attending Tobruk Medical Centre -Tobruk -Libya during the one-year period. The specimens were taken on midday and cultured immediately on MacConkey agar and blood agar by standard culture techniques.
Identification of the isolated organism was done on the basis of cultural characteristic and gram staining was performed to confirm the gram-negative bacilli. Apart from colony morphology, the routine biochemical tests were performed using API 20 system for Enterobacteraciae.
The resistance patterns of E.coli isolated strains to 14 antibiotics was determined by using discdiffusing methods and interpreted according to the Nccls (National committee for clinical Laboratory Subcommittee 1990). The following antimicrobial agents were obtained from (Oxoid, UK), Ampicillin, Amoxicillin/calvunic acid, Chloramphenicol, Cefrixon, Cephalexin, Gentamycin, Tetracycline, Nitrofurtoin, Sulfamethoxazole, Erythromycin, Penicillin, Cloxacillin, Oxacillin and Neomycin.
All these tests were performed on Muller-Hinton agar (Oxoid U.k). A 0.05 McFarland Suspension was applied to the plates, which were dried in an incubator at 35c•for 15 minutes, antimicrobial disc was placed on the agar with sterile forceps. The agar plates were incubated at 35c• for 15 hrs. The antibiotics effect for each antibiotics was measured as the diameter of the zone of inhibition.

Results and Discussion
Of the 480 urine samples tested from November 2015 to December 2016, 300 urine samples showed positive growth 162 (54%) were E.coli. (Table-1  E.coli strains were collectively tested for sensitivity and resistance against 14 antibiotics (Table -2). The antibiotics susceptibility of the isolates showed that E.coli strains were sensitive to Neomycin, Oxacillin and Nitrofurantoin with 100%, 99%, and 83% respectively.     Mathai et al., 2008 and Sahm et al., 200.In this study 95% of E.coli isolates were resistant to more than 3 antibiotics belonging to3 or more classes of antibiotics. However in our previous study Khamees, (2001), reported that 94.6% of E.coli strains were resistant to one antibiotic and more.  The increasing prevalence multidrug resistant pathogens is of considerable concern and worrisome as being public health and therapeutic challenge to clinical all over the world. Most encountered gram negative pathogens e.g. Klebsiella pneumonia and E.coli have the ability to acquire cross resistance to several antimicrobial agents (Khamees and Ghafir, 2017).In our study 60% of E.coli isolates showed multidrug resistance to 5-8 antibiotics ( belong in to 3 or < 3 different classes of drugs). F.g-1 3 These results are comparable to those studies found in Sudan by Ahmed et al., 2000;and Rabia et al., 2012 in Pakistan. Also 28% of the isolates from our study showed resistance to more than 8 drugs similarly (AL-Mardeni et al., 2009) in Jordan reported that 59.9% of E.coli isolates were resistant to three or more antibiotics. In addition, a study done in Saudi Arabia by Al-Tawafiq., (2006) reported 29% E.coli isolates were resistant to more than two antibiotics. However in study done by (Saeed et al.,2009) in Karachi, Pakistan 92% of gram negative clinical isolates including E.coli resistant to one or more antibiotics. All these results from different countries report more or less the same results.

Conclusion
A total of 162 E.coli strains were isolated from UTI positive urine samples . 99.3% of these isolated were multidrug resistant to 3 antibiotics and more from different classes only one strain was resistant to two antibiotics different resistant pattern occurred 3-10 times obtained.