Detection of Antibiotics Sensitivity at different pH levels for Proteus mirabilis Isolated from patients with Urinary Tract Infections

One hundred and sixty-nine samples of urine have been collected through the period from December/2016 to May/2017. Were for isolation and identification of Proteus mirabilis. Isolated from urine in patients with UTI. Identification was done by growing on different media and biochemical tests as well as the antibiotics susceptibility were studied by using twenty types of antibiotics at acidic pH, neutral pH and alkaline or basic pH by disc diffusion method. These antibiotics were involved Ciprofloxacin, Amikcin, Meromenem, Imipenem, Ampicillin, Rifampin, Gentamicin, Trimethoprim, Tetracycline, Amoxicillin, Sulfamethoxazole, Carbnicillin, Rifaximin, Penicillin-G, Oxolinic acid, Bacitracin, Clindamycin, Erthromycin, Novamicin and Aztreomycin. The Ciprofloxacin and Aztreomycin have high activity at both acidic and neutral pH, while the Amikcin, Meromenem, Imipenem and Ciprofloxacin have high activity at basicity pH against these bacteria.


I. Introduction
Urinary tract infections (UTI) medically classified as complicated infections and uncomplicated infections [1]. The uncomplicated urinary tract infections typically affect the individuals who are healthy of otherwise and contain no structural or abnormalities of neurological urinary tract [2]. These infections are differentiated into lower urinary tract infections known as cystitis and upper urinary tract infections known as pyelonephritis [3]. The complicated urinary tract infections are defined as infections associated with factors that compromise the tract of urinary or defense of host, including urinary retention and urinary obstruction caused by neurological disease, renal failure, renal transplantation, immune-suppression, pregnancy and the presence of foreign bodies such catheters or other devices [4].
The urinary tract infections are the most common clinical indication and causes of severe problems for public health and causes economic losses, however; the infections of the urinary tract caused by the range of pathogenic bacteria but most prevalence pathogens included P. mirabilis, E. coli, K.
pneumoniae, E. faecalis and Staph saprophyticus, and in addition, problem include increasing the range of antimicrobial resistance among these bacteria [5].
Bacteria Proteus is genera of gram negative bacteria and belonged to the family of Enterobacteriaceae, these bacteria were first time described by Hauser in 1885 and can be distinguished from other genera by their capacity to form swarms shape on agar surfaces media [6].
Proteus mirabilis is pathogens of gram negative bacteria and one of the most common pathogen in clinical specimens and can cause several types of hospital acquired diseases such as infections of the urinary tract, bloodstream and wounds [7]. Proteus mirabilis and many pathogens of gram negative and positive bacteria involved in urinary infections with capacity to form of biofilm [8]. And this increased rate of antibiotic resistance [9]. Some literatures reported that factors associated with antibiotics resistant prevalent in Proteus mirabilis [10].
Treatment and prevent urinary tract infection with successful start by using different drugs types not depends on pathogen susceptibility but also depend on numerous antibiotics and host factors such as pH of the urinary tract [11]. However, there are percent of little works has been done and described the regarding pH and antibiotic activity against pathogens and therefore only the few agents and uropathogens species have been identified [12] [13]. This is surprising, in addition, that urinary pH varies substantially within and across patients and this relatively easy to clinically adjustment and effect of this on antibiotic activity against gram negative and positive bacteria [14].

Aim of study
Determination of the antibiotics sensitivity for bacteria Proteus mirabilis isolated from urinary tract infections at acidic, neutral and alkaline levels for the pH.

Identification of Proteus mirabilis bacteria
The isolates were diagnosed as Proteus mirabilis species based on the findings of non-lactose fermenting colonies on macConkey agar with swarming on blood agar plate, characteristic fishy smell, microscopic examination show gram negative pleomorphic bacilli with active motility and the results of biochemical tests were negative for Gram stain, Oxidase and Indol. While, were positive for Catalase, Methyl red, Voscproscouer, Citrate and Urease. In addition, fermentation of glucose (with acid and gas) [15] [16].

Antibiotic susceptibility test
Muller Hinton agar plates have been used for identifying the susceptibility of antibiotics, this carried out by technique of disc diffusion method according to Bauer [17]. And the pH of this medium was adjusted at acidic pH with 0.1N of HCL, neutral pH and alkaline pH with 0.1N of NaOH by use of the PH meter.

III: Results
The one hundred and sixty-nine samples have been collected from urinary tract infected patients, one hundred and thirty-three samples were positively growing and found the thirty six isolates were identified as Proteus mirabilis from all isolates. These bacteria were identified by grown on different media and screened by several biochemical tests.    Table (1) the Proteus mirabilis isolates at pH =(5.5) were resistant to (Ampicillin), (Tetracycline), (Amoxicillin), (Erthromycin) and (Penicillin) antibiotics, which all have numbered and percent of resistant isolates were (35) and (100%), whereas these bacteria were less resistant to (Ciprofloxacin) and (Aztreomycin) antibiotics at same pH which have numbered and percent of sensitive isolates were (32), (91.482%) and (31), (88.571%) respectively.  Table (2) the Proteus mirabilis isolates at pH =(7) were resistant to (Ampicillin), (Tetracycline), (Amoxicillin), (Erthromycin) and (Penicillin) antibiotics which all have number and percent of resistant isolates were (35) and (100%), whereas these bacteria were less resistant to (Ciprofloxacin) and (Aztreomycin) antibiotics at same pH which have number and percent of sensitive isolates were (32), (91.482%) and (31), (88.571%) respectively.

IV: Discussion
When compared these results (figure:1) with the results for other studies, found the current results were agreed with Salih et al who found the percent of the Proteus mirabilis isolates from urinary tract infection was (21.7%) [18]. And disagreed with Abuhandan et al who found the percent of the Proteus mirabilis isolates from urinary tract infection was (8.4%) [19].
The pH for urinary tract can widely change from the acidic environment equal to 4.5 with alkaline environment equal to 8 [26]. And the values outside this range are may be rare and induce damage for tissue and formation of abnormal components like stones and salts [14]. However, Foster and Woodruff are first concluded that pH could influence the activity of Penicillin [27]. Indeed, little work has been donning for investigated the effect of pH on antibiotic activity [14].
The fluoroquinolones are widely used in treatment of urinary tract for both pyelonephritis and complicated infections [28]. However, the rates of resistance are still low in Europe and North America, but may trend of increasing resistance and this suggesting changes for its utility [29] [30].
Investigated studies in previous for these agents shown higher activities at highest of pH [11] [13]. This because increased interactions with membrane lipids and porins at high pH and this favorite for increase of antibiotic accumulation inside bacteria [31] [32]. This supports using alkalinizing agents with these antibiotics to increase its bactericidal activity [13]. However, in studying for Irwin et al who found the elevation pH of media from 5 to 9 caused a decrease in activity of fluoroquinolones against P. mirabilis, but the rates of kill for these antibiotics were most rapid at pH 7 [33].
Gentamicin antibiotic commonly used in urinary tract treatment with differences in its activity between pH (5 and 8) [14]. Studies in previously involving numerous of microorganisms have similar findings [34] [35]. However, because the increase of electrical potential across the membrane of bacteria at higher pH leading to elevate of antibiotic uptake [34]. Studies have shown uptake of this antibiotic is reduced under conditions of alkaline [36].
The trimethoprim and sulphamethoxazole activity against enterococci with higher pH, no depth in analysis concerning these agents and pH could be present [37]. b-Lactams antibiotics are generally not recommended as first line therapy for treatment urinary tract infections unless certain pathogens are implicated [29].

Conclusions
The activity of the antibiotics against Proteus mirabilis bacteria were, Ciprofloxacin equal 91.482% at both acidic and neutral pH, whereas the Amikcin and Ciprofloxacin equal 91.428% and 100% respectively at basicity pH.