الفهرس 
INTRODUCTION AND AIM OF THE STUDYOnly 14 pages are availabe for public view
 |  | from | 145 |  |  |
| | | from | 145 | | |
Abstract
CAUTIs are the most common infections in healthcare facilities. They are responsible for approximately 25% of hospital acquired infections globally, and result in increased morbidity and mortality. CAUTI is a recurrent problem for many older individuals who require long-term urinary catheters for bladder drainage. This problem interferes significantly with individual quality of life and is costly to society, both in terms of the expense of treatment and the resistant organisms that arise through the treatment of CAUTI.
Once an indwelling urinary catheter is inserted, bacteria quickly develop into biofilms that adhere to the catheter surface. Biofilm provides a sustained reservoir for microorganisms that can infect the patient. More than 90% of these infections are monomicrobial with E. coli, P.aeruginosa, Enterococci, Candida, Klebsiella, or Enterobacter spp. Longer catheterization inevitably leads to multi-organism biofilms.
The importance of controlling biofilm producing uropathogenic bacteria is related to protection provided by biofilm. Bacteria enter this biofilm, which protects them from the mechanical flow of urine, host defenses, and antibiotics, making bacterial elimination difficult and become responsible for colonization and persistence.
Treatment of biofilm-associated uropathogenic bacteria requires new strategies due to the high levels of antibiotic resistance conferred by biofilm structures. A very promising approach for the control of biofilm formation is the use of probiotics which are defined as live organisms which when administered in adequate amounts confer a health benefit on the host. These non-pathogenic bacteria are well-known since they contain many beneficial properties to control pathogenic microorganism’s ability. These properties include adherence to cells, reduction of pathogenic bacterial adherents and co-aggregation, and production of organic acids which antagonize pathogenic microorganisms.
The present study aimed to:
1- Isolate and identify different uropathogens from urine samples of catheterized patients and testtheir antimicrobial susceptibility patterns.
2- Examine theability of uropathogenic isolatesto biofilm formation.
3- Examine the ability of some LAB spp. to prevent in-vitro colonization and biofilm formation of some isolated uropathogens on Foley urinary catheters’ surfaces.
The study was conducted over a period of 7 months from January to July 2019. It enrolled 120 urine samples randomly collected from adults with indwelling Foley urinary catheters who were admitted to the Urology Department at AMUH.
Urine samples were aseptically collected from catheterized patients by the nursing staff to avoid any contamination during collection or handling. The catheter tubing distal to the puncture site was clamped for 15 to 30 minutes before the aspiration of urine, to allow urine to fill the tubing. The catheter port was then disinfected using 70.0% ethanol. Urine samples were obtained by aseptically inserting sterile syringes and then transferred into labelled, screw capped sterile containers. All the collected samples were transported within 2 hours in an ice box to HIPH Microbiology Laboratory for processing.
A standard one micron (0.001ml) loop was inserted vertically into the well mixed urine, and was then streaked over the surface of each of well dried blood, MacConkeyʼs and SDA plates. Blood and MacConkeyʼs agar plates were incubated aerobically at 37oC for 24 hours, while SDA plates were incubated at 25oC for 48 hours and up to 10 days. Quebec colony counter was used for counting the colonies. The number of counted colonies was multiplied by 1000 to calculate the number of CFU per ml in the original sample. Plates yielding ≥105 CFU/ml of one or maximally two organisms were considered positive for UTI.
After proper incubation, identification of isolated colonies was performed according to the standard microbiological methods. All bacterial isolates were subjected to antibiotic susceptibility testing by disc diffusion method according to CLSI recommendations. Some isolates were confirmed using Vitek 2 compact system.
The BFA of the identified isolated uropathogens (38 bacteria and 5 Candida spp. were tested by using MtP method. Then, probiotic CFSswere examined for their ability to produce biofilm and prevent colonization and biofilm formation of some of the isolated uropathogensusing MtP.The experiments were performed in triplicates and the results were averaged. All examined strains were classified into the following categories: non-biofilm former (0), weak biofilm former (+), moderate biofilm former (++), or strong biofilm former (+++), based upon the measured ODs.
Sterile Foley catheters were purchased from the market. Immobilization of LAB (L.acidophillus, L. plantarum, L. paracasei, L. pentosus and Bifidiobacterium ) was done using sodium alginate and calcium chloride solutions. The catheter pieces containing immobilized probioticcells were immersed in broth cultures of the selected eight urine isolates (two K,pneumoniae, two E.coli, one P.mirabilis, one P.aeruginosa, one Enterococcus spp. and one Candida spp.) in separate sterile bottles and were allowed to stand for 6 days at 37°C. Biofilm formation on the catheter sections was evaluated by viable cell count procedures after 2,4 and 6 days.
The results of the present study revealed that:
1. Of the 67 patients who had been catheterized for less than or equal to two days, only 8 (20.5%) patients hadCAUTIs, while of the 53 patients who had been catheterized for more than two days, 31 (79.5%) had CAUTIs.
2. Of the 120 examined urine samples, 81 (67.5%) showed no growth, while 39 (32.5%) samples yielded uropathogenic isolates.
3. Of the 120 examined urine samples, 35 samples (29.1%) yielded monomicrobial agents (31 bacterial isolates and 4 Candida spp.) and only 4 samples (3.3%) showed two isolates (E.coli and Candida spp. in one sample and mixed two bacterial isolates in the other 3 samples) with a total of 38 bacterial isolates and 5 Candida spp.
4. Out of the 43 bacterial and fungal isolates, 32 (74.4%) were gram negative bacilli, 6 (14.0%) were gram positive cocci and only 5 (11.6%) were fungi.
5. The most common microbial isolate was K. pneumoniae (37.2%), followedbyE.coli (27.9%).TheywerefollowedbyEnterococcus spp. (14.0 %), Candida spp. (11.6%) and P. aeruginosa (4.7%). One of each P.mirabilisand M. morganii, were also isolated representing 2.3%each.
6. Twenty-seven (71.1%) bacterial isolates were MDR. M.morganii represented (100.0%), followed by E. coli (91.7%), K.pneumoniae (82.3%), P. aeruginosa (50.0%) and Enterococcus spp.(16.8 %).
7. Half oftheK.pneumoniae isolates(50.0%) were susceptible to imipenem, while 43.8%and31.3% were susceptible to amoxicillin-clavulanate and gentamycin,respectively.The lowest susceptibility percentage was recorded for cephazolin(6.3%).
None of K.pneumoniae isolates was susceptible to nitrofurantoin or fosfomycin.
8. The highest susceptibility percentages of E.coli were recorded for imipenem (66.7%) then fosfomycin (58.3%) and nitrofurantoin (50.0%). The lowest susceptibility percentages were recorded for ampicillin, cephazolin, ceftriaxone, ceftazidime, ciprofloxacin and gentamycin (8.3%) each.
9. The majority of K.pneumoniae isolates (87.5%) were positive for BFA, while only one third (33.3%) of E.coli isolates showed positive BFA.
10. The two P.aeruginosa isolates and the one P.mirabilisisolate had positive BFA (100.0% each), while the one M.morganii isolate had no BFA (0.0%).
11. Regarding Enterococcus spp., 5/6 (83.3%) of the isolates were biofilm producers, and regarding fungi, 3/5 isolated Candida spp. (60.0%) had BFA.
12. About two thirds (67.44%) of all uropathogenic isolates were positive for BFA.
13. All the 5 probiotic strains converted the two selected E.coli strains and oneK.pneumoniae (strain two) from biofilm forming to non biofilm forming.
14. Only L.acidophilus and Bifidiobacterium converted selected Enterococcus spp. from biofilm forming to nonbiofilm forming, while all probiotics except L.plantarum had the same effect on selected Candida spp.
15. All the five selected probiotics had an inhibitory effect on the growth of all the tested uropathogens but with varying intensities according to the duration of application.
16. The count of some of the tested uropathogens decreased to <103CFU/ml after 4 and 6 days of L.acidophilus application, respectively {E.coli (strains one& two),
K. pneumoniae (strains one& two)}, while regarding P. aeruginosa and Enterococcus spp. their counts decreased to ≥103 : <105 CFU/ml after 4 days of application and decreased to <103 CFU/ml of Enterocoocus spp. after 6 days of application.
17. The count of some of the tested uropathogens decreased to <103CFU/ml after 4 and 6 days of Bifidiobacterium application {E.coli (strains one& two),K. pneumoniae(Strain two) and Enterococcus spp.}, while no growth of Candida was detected after 6 days of application.
18. The count of some of the tested uropathogens decreased to <103CFU/ml after 4 and 6 days of L.paracaseiapplication{E.coli (strains one& two),and
Enterococcusspp.}, while regarding K.pneumoniae (strain two), the count decreased to <103CFU/ml only after 6 days of application.
19. The count of some of the tested uropathogens decreased to <103CFU/ml after 4 and 6 days of L.pentosusapplication {E.coli (strains one& two) and Enterococcus spp.}, while regarding K. pneumoniae(strain one) and Candida spp. their counts decreased to <103CFU/ml only after 6 days of application.
20. The count of some of the tested uropathogens decreased to <103CFU/ml after 4 and 6 days of L.plantarum application{(E.coli (strains one& two),K. pneumoniae(Strains one& two)}, while regarding P. aeruginosa, Enterococcus spp. and Candida spp. their counts decreased to ≥103 : <105 CFU/ml after 4 and 6 days of application.
It can be concluded from the present study that:
1. Themostcommonencountered uropathogen causingCAUTIswasK. pneumoniae, followedbyE.coli.
2. There was a significant association between the duration of catheterization and CAUTI.
3. The majority of the isolated bacterial uropathogens were gram-negative bacilli, biofilm formers, and resistant to commonly prescribed antimicrobial agents.
4. Imipenem was the most effective antimicrobial agent against CAUTIs caused by
K. pneumoniae and E.coli.
5. Probiotics had the potential to prevent urinary catheter colonization and inhibit biofilm formation.
6. L.acidophilus was found to have a significant inhibitory effect on BFA and colonization of tested uropathogens(two K,pneumoniae, two E.coli, one P.mirabilis, one P.aeruginosa, one Enterococcus spp. and one Candida spp.)on Foley urinary catheters.
7. Probiotics caused significant reduction in uropathogenic counts after 4 and 6 days of application.
from the results of the present study, the following recommendations are suggested:
1- Avoiding the unnecessary use of urinary catheters, and limiting the catheterization days to the minimum as possible.
2- Regular monitoring of the antimicrobial resistance patterns of uropathogens to guide the appropriate treatment choices.
3- Probiotics (especially L.acidophilus) can be exploited to inhibit colonization and biofilm formation of uropathogens on Foley urinary catheters.
4- This study presents an interesting intervention strategy that should be further evaluated in large scale studies for in-vivo use.