URINARY TRACT INFECTIONS IN POST OPERATIVE PATIENTS: PREVALENCE RATE, BACTERIAL PROFILE, ANTIBIOTIC SENSITIVITY AND SPECIFIC RISK FACTORS

Background and objective: Urinary tract infections (UTIs) are the most common minor complication after operations, mostly due to bladder catheterization that used routinely during operations. This investigation seeks to determine prevalence rate, bacterial features, antibiotic sensitivity and risk factors for urinary tract infection in postoperative patients in tertiary hospitals in Sana’a, Yemen. Methods: This prospective analysis included 390 patients undergoing surgery between 2017 and 2018 at Al-Thawra Hospital. The study includes 258 male and 132 female between the ages 5 to 80 years. Clinical and demographic data and factors affecting UTIs were collected in the standard questionnaire, and the sample was obtained after catheter removal; or, in patients with a clinical indication of continuous catheterization, a sample was obtained after the replacement of a new catheter. The samples were cultured, examined for significant possible bacterial pathogens, isolated and identified by standard laboratory techniques, and microbial sensitivity testing was carried out by disc diffusion method. The operative characteristics associated with postoperative UTI were also analysis. Results: Postoperative UTI (POUTI) occurred in 144/390 (37%), and the predominant post-operative uropathogen was Escherichia coli (34%), followed by Pseudomonas aeruginosa 1(27%) and Staphylococcus coagulase negative (16.7%). In Gram-negative bacteria, high resistance to ampicillin (95%), nalidixic acid (63%), ceftriaxone (68%) and cotrimoxazole (55%) was recorded, while high sensitivity to amikacin (98%) and ciprofloxacin. (84%), cefotaxime (87%), gentamicin (87%) and imipenem (98%). In Gram-positive bacteria, high resistance to penicillin (90%), erythromycin (85%), and amoxicillin (78%) was recorded, while high sensitivity to aztreonam (94%), augmentin (83%), ciprofloxacin (93%), cefotaxime (86%), gentamicin (85%), Rifampicin (100%) and vancomycin (97%). The following characteristics are independently associated with postoperative UTI: female sex (OR 2.1, 95% CI 1.3–3.2), Rubber PTFE catheter (OR 4.7, 95% CI 1.99–11.4), longer duration of catheterization >10 days (OR 4.4, 95% CI 2.3–8.3), overweight (OR 1.7, 95% CI 1.1–2.9), and emergency surgery (OR 1.9, 95% CI 1.2–3.0). Conclusions: POUTI remains an important problem in our hospitals and what complicates the situation is that all the causative microorganisms are MDR with few treatment options; and several risk factors were independently associated with POUTI.


INTRODUCTION
Urinary tract infection is the fourth most important cause of healthcare-related infection 1 with around 70% -80% attributable to improper use of indwelling urinary catheters 2 . Catheter UTI (CAUTI) is connected with escalated morbidity and mortality and extended the length of hospital stay 2 . Indwelling bladder catheterization is a recognized risk factor for developing UTIs 3 . There is no commonly recognized guideline concerning catheterization in the perioperative setting, to date, with surgeon preferred mainly bladder management 4, 5 . Practice catheterization has been used in various surgical centers with the purpose of avoiding postoperative urinary retention, something that patients undergo during operation are recognized to be at increased risk, and that itself is associated with UTIs 6,7 . UTIs account for between 13-15% of all health care-related diseases worldwide, leading to long hospital stays, increased health care expenditures, and an increased mortality rate 2, 8 . Postoperative UTIs are estimated at 30.26% 9 . POUTIs are described as the most common minor systemic complications after operations, which exceeding pneumonia, deep venous thrombosis, and renal insufficiency 8 . Also, POUTIs have been linked to considerable unfavorable events such as implant failure, periprosthetic infection, and subsequent revision procedures, consequential in extended and costly hospital stays 10- 14 . This investigation seeks to determine prevalence rate, bacterial profile, antibiotic sensitivity and specific risk factors for UTI in post operative patients in tertiary hospitals in Sana'a, Yemen.

SUBJECTS AND METHODS
The study design was an active prospective follow-up study.

Data analysis
The data were statistically analyzed by a software version for statistical significance (Epi Info version 6, CDC, Atlanta, USA). First rates were calculated, then from two-by-two tables, the independence odds ratios* were calculated and P-value was determined using the uncorrected chi square test. Fisher's exact test was used for the small expected cell sizes with a two-tailed probability value. *Associated risk factors are generally defined independently in the statistical sense: the variable is called an independent risk factor if it has a significant contribution to the outcome in a statistical model that includes established risk factors.

DISCUSSION
CAUTI is the most common hospital infection and accounts for about 30-40% of all hospital acquired infections and is a major source of hospital sepsis and related deaths in acute care hospitals 16 . Current study examined bacterial POUTI rate in postoperative patients at Al-Thawra University Hospital along with testing for common risk factors and common pathogens associated with bacterial post operative UTI. In the current study, the bacterial POUTI rate was found to be 37% (144/390). These infections are mainly bacterial infections, and previous studies have shown that about 26% of patients who have an indwelling urinary catheter in place for 2-10 days will develop bacteriuria, and 25% of these patients will develop bacterial CAUTI. Obtained results are to some extent higher than published rates perhaps because all of the patients enrolled in this study had undergone operations and stayed longer in hospitals and had a number of risk factors that increase the opportunity of the development of bacterial CAUTI 17, 18 . Substantial research has been done on nosocomial UTIs in general 16 26 . This association can be explained by increasing the duration, most probably increases the chance of bacteria ascending to the bladder either around the catheter or throughout its lumen. Also, increased period of catheterization has been a important factor linked with acquiring CAUTI in this study (>6 days) as has been shown in many other studies 23, 26 . Also, the two mainly significant factors that lead to the occurrence of CAUTIs and have been the main focus of quality improvement areas are unnecessary urinary catheter placement and inappropriate delay in removing a catheter when it is no longer needed 27, 28 . Regrettably, 38% of attendance physicians are unconscious that their patients have a urinary catheter in place 29 . In addition, in 20% to 50% of cases, there is no obvious sign in favor of catheter placement 1,29 . Table 4: The frequency of bacterial causative agents of CAUTI in post operative patients Diabetes mellitus was not significant independently associated with postoperative UTI, (OR 1.7, 95% CI 0.8-3.3, p=0.1) ( Table 3). These results are contrary to Saint et al., and Lobdell et al., studies where one of the risk factors for developing CAUTI is diabetes mellitus 30,31 . Emergency surgery was independently associated with postoperative UTI (OR 1.9, 95% CI 1.2-3.0) ( Table 3). With respect to postsurgical patients in further surgical specialties, investigation reveals that the appreciable incidence of postoperative UTIs is not exclusive to type of surgeries 11 . Table 5:Antibiotic pattern of Gram negative bacteria (101) isolated from post-operative patients, Sana'a, Yemen.
One study exploring the incidence of postoperative UTIs subsequent major surgeries in a variety of specialties discovered that the prevalence are certainly similar across multiple surgical services: 30-day postoperative UTI rate for coronary artery bypass, vascular, colorectal, and TJA surgeries were 3.3, 3.4, 4.0, and 3.4%, respectively 11 . were less frequent (  33 . Also the current study results are different from findings by Rebmann and Greene study ; and Gaynes and Edwards reviews in which Klebsiella spp. were the most commonly identified bacteria (8/16, 50%), followed by Enterococci (7/16, 44%). Although E. coli is known to be the most predominant etiology for UTI 24,34 , it was isolated from 34% of positive bacterial culture patients enrolled in this study. This finding might suggest dissimilarity in bacterial population consistent with different locality and suggests a role of the environment in determining the bacterial population in each hospital 35 . All bacterial postoperative uro-pathogens were found to be resistant to most of the tested antimicrobials (Table 5 and Table 6). These results are consistent with previous studies that demonstrated that organisms recovered from hospitalized patients are often resistant to multiple antibiotics 36-38 . The high rate of MDR among nosocomial pathogens reflects the extensive use of antimicrobials in the hospital in addition to the huge ability of the organism to acquire resistance genes 39, 40 . Amikacin and imipenem were the most active drugs against Gram negative bacteria (98% sensitivity). Rifampicin and vancomycin were the most active drugs against Gram positive bacteria (100% and 99% sensitivity, respectively). The current findings are similar to that reported by Daef  On the other hand, other antibiotics were found to have high and moderate resistance to all bacterial postoperative uro-pathogens, and this constant increase in antibiotic resistance over time is frightening and creates a risk for patients with it being the only antimicrobial option to isolate MDR.

CONCLUSION
Present study has identified multiple properties independently associated with postoperative UTIs, which may be helpful for clinicians in classifying patients at risk. While this information alone may have the potential to improve the quality of patient care, at this time, the clinical utility of these risk factors is unproven. Further research such as a prospective study stratifying patients into risk groups to guide postoperative management or perioperative catheterizeation may be employed to establish practical utility.

RECOMMENDATIONS
CAUTI remains a huge problem in our hospitals and what makes it worse is that all causative microorganisms are MDR with few treatment options. According to obtained results, amikacin, and imipenem can be used for empirical treatment. The Comprehensive Unit-based Safety national program, must be applied in our hospitals that aim to reduce catheterassociated urinary tract infections (CAUTIusts) by focusing on proper technical skills, behavioral changes, education, and feedback. Implementation of the CUSP recommendations to reducing catheter use and CAUTIs in post-operative patients. The program will be likely successful because it included both socio-adaptive and technical changes and allowed the individual hospitals to customize interventions based on their own needs.