Nosocomial infections include catheter-associated urinary tract infections (CAUTIs), which rank high among healthcare-associated infections globally. Catheterization length, lack of proper care, and preexisting medical issues all contribute to an elevated risk of infection. Bacteria can attach to and colonize indwelling urinary catheters, which allow them direct access to the urinary tract [1, 2].
The development of biofilms is a key component in the maintenance and reappearance of CAUTIs. Structured populations of bacteria encased in an extracellular polymeric matrix that cling to either living or nonliving surfaces (e.g., catheter materials) are called biofilms.

Bacteria within a biofilm change their metabolic activities and become more resistant to the host's immune system and drugs. Pathogens are able to evade antibiotic treatment thanks to this defense mechanism, which causes infections to persist and even recur [3, 4].

 Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus species, and Enterococcus species are among the common bacterial pathogens that can cause catheter-associated urinary tract infections (CAUTIs). Treatment is already complicated since many of these microbes are multidrug resistant and can build thick biofilms. A significant therapeutic hurdle in healthcare facilities is the rise of biofilm-forming bacteria that are resistant to antibiotics [5, 6].

In order to effectively control infections and manage patients, it is essential to understand how biofilm formation relates to antibiotic resistance. Reduced morbidity, healthcare expenditures, and hospital stay duration can be achieved with early detection of biofilm-producing pathogens and proper antibiotic stewardship methods [7, 8].

Bacterial isolates from patients with catheter-associated UTIs in a tertiary care hospital were analyzed for antibiotic resistance patterns and biofilm development in the current study.

This study was conducted at Department of Microbiology, Department of Microbiology, Tagore Medical College and Hospital Kelambakkam-Vandalur Road, Chennai, Tamil Nadu, between February 2010 to January 2011. 50 unique bacterial isolates were acquired from urine samples of catheterized patients clinically suspected of having catheter-associated urinary tract infection (CAUTI). Midstream urine samples or urine obtained aseptically via the catheter sampling port were processed within one hour of collection. Samples were cultivated on Cysteine Lactose Electrolyte Deficient (CLED) agar and MacConkey agar, then incubated at 37°C for 18 to 24 hours. Significant bacteriuria was defined as ≥10⁵ colony-forming units (CFU) per milliliter.

Inclusion Criteria:

• Patients with indwelling urinary catheter for more than 48 hours.
• Patients clinically suspected of CAUTI with symptoms such as fever, suprapubic tenderness, or altered urine characteristics.
• Urine samples showing significant bacteriuria (≥10⁵ CFU/mL).
• Non-duplicate bacterial isolates obtained during the study period.

Exclusion Criteria:

• Patients with community-acquired urinary tract infections.
• Patients catheterized for less than 48 hours.
• Contaminated urine samples or mixed growth of organisms.
• Duplicate isolates from the same patient.
• Patients already receiving prolonged antibiotic therapy prior to sample collection.

Statistical Analysis:

Microsoft Excel was used for data entry, while SPSS version 25.0 was used for analysis. The frequencies and percentages were used to express the categorical variables. When looking for a correlation between biofilm development and antibiotic resistance, the Chi-square test was used. It was deemed statistically significant if the p-value was less than 0.05.

We got 50 different bacterial isolates from catheterized patients who were thought to have CAUTI. We looked at the distribution of organisms, the creation of biofilm, and the patterns of antibiotic resistance.

Table 1: Distribution of Bacterial Isolates from CAUTI Patients

Escherichia coli (44%), Klebsiella pneumoniae (24%), and Pseudomonas aeruginosa (16%) were the most prevalent bacteria isolated. The majority of the microorganisms that cause CAUTIs were Gram-negative bacteria.

Table 2: Biofilm Formation among Bacterial Isolates

The percentage of biofilm-forming isolates was 64 percent, or 32 out of 50. Of them, 28% were very effective at producing biofilms, 20% were moderate, and 16% were not at all effective. Biofilm formation was absent in just 36% of the isolates.

Table 3: Organism-wise Distribution of Biofilm Producers

Pseudomonas aeruginosa formed biofilms 75 percent of the time, followed by Escherichia coli (68.2%), and Klebsiella pneumoniae (66.7%). The ability to create biofilms was stronger in Gram-negative organisms than in Gram-positive isolates.

Table 4: Antibiotic Resistance Pattern among Biofilm Producers

Commonly used antibiotics were shown to have significant resistance rates among biofilm-producing isolates, with ampicillin (81%), ciprofloxacin (75%), and ceftriaxone (68%). Using nitrofurantoin and imipenem resulted in less resistance.

Table 5: Comparison of Multidrug Resistance (MDR) Between Biofilm and Non-Biofilm Producers

*Statistically significant

Isolates that produced biofilms had a considerably greater rate of multidrug resistance (65.6% vs. 27.8%, p < 0.01). There seems to be a robust correlation between the development of biofilms and the rise in antibiotic resistance.

Catheter-associated urinary tract infections (CAUTIs) are still a major cause of death in hospitalized patients, especially those who have had a catheter in for a long time. Biofilm formation is a key part of how these illnesses stay alive and come back [9, 10].
The majority of the CAUTI isolates in this study were Gram-negative organisms. Escherichia coli (44%), Klebsiella pneumoniae (24%), and Pseudomonas aeruginosa (16%) were the most common pathogens. This distribution fits with what we know about how urinary tract diseases spread, which is that Enterobacteriaceae are often involved [11, 12].

 
The last study, which was done in tertiary care settings, also found that E. coli was the most common sample in CAUTIs. It was followed by Klebsiella and Pseudomonas species. These results show that Gram-negative bacilli are still the most common type of infection linked to catheters in a variety of healthcare situations [13].
In this study, biofilm development was seen in 64% of isolates, which shows that pathogens that make biofilm are common in CAUTIs. 28% of these were very good at making biofilm. The high rate of biofilm production shows that bacteria that are attached to catheters can stick to the surfaces of catheters and stay there even after antibiotic treatment [14, 15].

 
The last study found that biofilm production rates for CAUTI isolates ranged from 50% to 70%, which is very similar to what this study found. Biofilm helps germs stay alive by shielding them from antibiotics and the immune system of the host. According to this study, Pseudomonas aeruginosa made the most biofilm (75%), followed by E. coli (68.2%) and Klebsiella pneumoniae (66.7%). These organisms are known for their ability to stick to surfaces and make extracellular matrix, which makes growth more likely to last [16, 17].

 
Similar findings were made in the earlier study, which found that Pseudomonas and Klebsiella species were strong biofilm formers. This trait makes them much more resistant to multiple drugs and more likely to cause long-lasting infections [18, 19].

 
This study found that biofilm-forming isolates were very resistant to popular antibiotics like ceftriaxone (68%), ciprofloxacin (75%), and ampicillin (81%). Ipenem and nitrofurantoin, on the other hand, showed less tolerance. These results show that there aren't many ways to treat infections caused by pathogens that make biofilm [19, 20].

In the previous study, it was repeatedly found that biofilm producers had higher antibiotic resistance than non-producers. Biofilms have an extracellular polymeric framework that makes it hard for antibiotics to get through and encourages horizontal gene transfer, which makes the biofilms resistant to many drugs [21].
This study found that multidrug resistance was significantly higher among biofilm makers (65.6%) compared to non-biofilm producers (27.8%), and the link was statistically significant (p < 0.01). This result makes it very clear that biofilm formation and antimicrobial resistance are strongly linked. As seen in the previous study, there was a strong link between biofilm formation and multidrug tolerance. This shows how important it is to find strains that make biofilm in everyday lab work [22, 23].

 
According to the results of this study, it is very important to take good care of catheters, take them out early, and use antimicrobial management programs to stop biofilm-associated infections. A recent study found that strict infection control measures and reasonable antibiotic policies can lower the number of CAUTIs and stop the spread of pathogens that make biofilms that are resistant to antibiotics [24-26].

Among the bacterial isolates collected from UTIs caused by catheters, biofilm development was shown to be very common (64%). The most common pathogens and capable of building biofilms were gram-negative bacteria, specifically Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Antibiotic and multidrug resistance were shown to be considerably greater in biofilm-producing isolates compared to non-biofilm producers in this investigation. These organisms present a clinical issue because to the statistically substantial relationship between biofilm formation and multidrug resistance. Timely removal of indwelling catheters, establishment of antimicrobial stewardship programs, rigorous adherence to catheter care guidelines, and early detection of biofilm-producing organisms are all highlighted by the findings. Reducing treatment failure, recurrence, and the overall burden of CAUTIs requires preventive efforts in addition to sensible antibiotic usage.

Funding

None

 Conflict of Interest:

None

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