PREVALENCE AND ANTI MICROBIAL SUSCEPTIBILITY PATTERN OF CITRO BACTER AS AN UROPATHOGEN INATERTIARY CARE HOSPITAL

Uropathogens are microorganisms that are capable of causing infections of the urinary tract. Urinary tract infection (UTI) is the third most common infection experienced by humans after respiratory and gastrointestinal infections. [1]

 

Citrobacter is prevalent worldwide as it is a component of the normal intestinal flora. The genus Citrobacter is a distinct group of facultative anaerobic, Gram-negative bacilli belonging to the family Enterobacteriaceae and the tribe Citrobactereae. They are found singly or in pairs and are typically motile by peritrichous flagella, utilizing citrate as the sole source of carbon. [2]

 

There are 11 different species of Citrobacter (Citrobacter freundii, Citrobacter koseri, Citrobacter amalonaticus, Citrobacter farmeri, Citrobacter youngae, Citrobacter braakii, Citrobacter werkmanii, Citrobacter sedlakii, Citrobacter rodentium, Citrobacter gillenii, and Citrobacter murliniae), among which the species most commonly isolated from human clinical specimens are C. koseri (formerly C. diversus), C. freundii, C. youngae, C. braakii, and C. amalonaticus. [2]

 

Citrobacter isolates are reported to be the third most common organisms causing urinary tract infections in hospitalized patients after Escherichia coli and Klebsiella species, accounting for 9.4% of all isolates. [3] Thus, laboratory diagnosis is essential to accurately differentiate between Citrobacter species. As these organisms catabolize glucose and numerous other carbohydrates with the production of acid and gas, biochemical tests such as oxidase, catalase, methyl red, Voges–Proskauer, and citrate utilization tests are used for species identification. Antimicrobial susceptibility testing was performed for all isolates using the Kirby–Bauer disc diffusion method as recommended by the Clinical and Laboratory Standards Institute (CLSI) M2-A9 guidelines. [2]

 

Citrobacter species are often resistant to routinely used antibiotics, especially extended-spectrum cephalosporins, due to the overexpression of beta-lactamases. [4] This study aimed to assess the prevalence and antibiotic sensitivity pattern of Citrobacter in patients with UTIs in a tertiary care hospital.

 

 

 

 

 

In Citrobacter freundii- Highest antibiotic susceptibility was observed in Levofloxacin (100%) followed by Ofloxacin (76.19%) and Amikacin (76.19%) whereas Least antibiotic susceptibility was seen to Norfloxacin (50%) and Cephalothin (50%).

In Citrobacter diversus- Highest antibiotic susceptibility was observed in Levofloxacin (78.57%) followed by Ofloxacin (42.85%) and Amikacin (42.85%) whereas Least antibiotic susceptibility was seen to Amoxyclav (0%).

In Citrobacter amalonaticus- Highest antibiotic susceptibility was observed in Levofloxacin (90%) followed by Ofloxacin (60%) and Amikacin (60%) whereas Least antibiotic susceptibility was seen to Cefotaxime (9.09%).

120%   100%   80%   60%   40%   20%   0%

CITROBACTER FREUNDII

CITROBACTER DIVERSUS

CITROBACTER AMALONATICUS

ANTIBIOTICS

ANTIBIOTIC SUSCEPTIBILITY PATTERN OF CITROBACTER IN UTI PATIENTS

GRAPH 2(B): Higher (Reserved) Antibiotic susceptibility pattern of Citrobacter isolated from UTI patients (n=45)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

40%   35%   30%   25%   20%   15%   10%   5%   0%

CITOBACTER FREUNDII

CTROBACTER DIVERSUS

CITROBACTER AMALONATICUS

HIGHER (RESERVED) ANTIBIOTIC SUSCEPTIBILITY PATTERN OF CITROBACTER IN UTI PATIENTS

HIGHER (RESERVED) ANTIBIOTICS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In Citrobacter freundii- Highest antibiotic susceptibility was observed in Polymyxin B (29.41%) followed by Meropenem (17.64%), Imipenem (17.64%) and Tigecycline (17.64%) whereas Least antibiotic susceptibility was seen to Cephalosporins.

In Citrobacter diversus- Highest antibiotic susceptibility was observed in Polymyxin B (35.24%) followed by Tigecycline (23.52%) whereas Least antibiotic susceptibility was seen to Cephalosporins.

In Citrobacter amalonaticus- Highest antibiotic susceptibility was observed in Polymyxin B (17.64%) and Tigecycline (17.64%) whereas Least antibiotic susceptibility was seen to Cephalosporins.

The present study was carried out at MGM Medical College and Hospital. 230 urine samples of UTI patients were collected from December 2022 to February 2024.

 

Out of 230 UTI patients, 45 Citrobacter were isolated from urine samples. In our study, the overall Prevalence of Citrobacter was reported as 19.56% (45/230). A study done by Hiba Sami et.al reported the prevalence rate of Citrobacter in UTI patients as 3.46% (246/7099). [1] In another study conducted by Abdulrasheed B. Abdu et.al, the prevalence rate of uropathogenic Citrobacter was found to be 30.01% (1407/5000). [7] So, in various studies, it was seen that the prevalence rate of Citrobacter in UTI patients ranged from 3.46% to 30.01%.

 

In our study, it was observed that the maximum number of UTI patients with Citrobacter belonged to the age group between 61-80 (48.88%) years of age. A comparable study done by Poonam AR et.al showed that the majority of the age group affected in the present study is the elderly age group of 51-80 years. [3] In another study conducted by Navin Kumar Choudhary, the prevalence of UTIs in men increases substantially after the age of 60 years due to urethral obstruction and voiding dysfunction associated with prostatic hypertrophy.[8] This shows that advanced age is one of the host characteristics that predispose to UTI patients with Citrobacter.

 

In our study, the maximum number of UTI patients with Citrobacter was Male (55.55%). The study was done by Nandini. M.S et al. documented a similar prevalence with 61.11% males and 38.88% females patients[9]. In another study done by Jaggi et.al[10], also showed similar findings as our study. In all three studies, it was observed that UTI with Citrobacter was more commonly seen in males, a reason for this contradictory finding could be that in all 3 studies, a greater number of males were Catheterised as compared to females and Catheterisation has always been a significant predisposing factor for development of UTI.

 

In our study, Catheterization (46.66%) and Type II Diabetes Mellitus (35.55%) showed the highest risk of developing UTI with Citrobacter. In another study done by Shiva Verma et. al [11] confirmed that Diabetes and the duration of Catheterization increase the risk of developing CAUTI. This indicates Diabetes and patients on Catheterization have a greater risk of developing urinary tract infections.

 

In the present study, the commonest species of Citrobacter associated with UTI was Citrobacter freundii (46.66%) followed by Citrobacter diversus (31.11%) and Citrobacter amalonaticus (22.22%). In a comparative study done by Abdulrasheed B. Abdu et.al, Citrobacter freundii (60.4%) was found to be the most prevalent among the uropathogenic Citrobacter species. While, Citrobacter diversus constituted (29.9%), of Citrobacter amalonaticus (4.85%) of the isolates.[11] However, this indicates that Citrobacter freundii is the most frequently caused UTI in patients followed by Citrobacter diversus and Citrobacter amalonaticus.

 

In this study, it was observed that Citrobacter freundii found in patients with urinary tract infections showed the highest susceptibility to Levofloxacin (100%), followed by Ofloxacin (76.19%) and Amikacin (76.19%). On the other hand, the least susceptibility was observed for Norfloxacin (50%) and Cephalothin (50%). Interestingly, in the case of higher antibiotics (reserve), the highest susceptibility was seen in Polymyxin B (29.41%), followed by Meropenem (17.64%), Imipenem (17.64%), and Tigecycline (17.64%). Meanwhile, the least susceptibility was seen in Cephalosporins.

 

In the case of Citrobacter diversus, the antibiotic that showed the highest susceptibility was Levofloxacin (78.57%), followed by Ofloxacin (42.85%) and Amikacin (42.85%). On the other hand, the antibiotic that showed the least susceptibility was Amoxyclav (0%). When it comes to higher (reserve) antibiotic susceptibility patterns, Polymyxin B (35.29%) showed the highest susceptibility, followed by Tigecycline (23.52%). The least susceptibility was seen with Cephalosporins.

Regarding Citrobacter amalonaticus, the bacteria showed the highest susceptibility to Levofloxacin (90%), followed by Ofloxacin (60%) and Amikacin (60%). On the other hand, Cefotaxime exhibited the least

 

susceptibility (9.09%). When it comes to higher (reserve) antibiotics, Polymyxin B and Tigecycline showed the highest susceptibility (17.64%), whereas Cephalosporins exhibited the least susceptibility. In another study done by Poonam AR et.al, the susceptibility pattern observed in C.freundii urine isolates in the case of nitrofurantoin (89.4%, 79%), nalidixic acid (80.7%, 62.5%) and trimethoprim-sulfamethoxazole (96.4%, 75%) in both C. koseri and C. freundii. High-end antimicrobials such as tigecycline and colistin showed excellent susceptibility of 100% in both Citrobacter species isolated. [3]

 

Several studies have reported a rise in antibiotic resistance among Citrobacter species in different regions of India. However, the current study shows a significant level of susceptibility. The variation in the specimens considered, hospital environments, and hospital infection control policies could contribute to the difference.[3]

Overall Prevalence rate of Citrobacter in UTI patients is 19.56% in our study.

 

Patients between the ages of 61-80 years are at a higher risk of developing Citrobacter in their urine.

 

Male predominance was seen in our study.

Citrobacter is more likely to cause UTI in patients who have undergone Catheterization (46.66%) or have Type II Diabetes Mellitus (35.55%).

 

The most common species of Citrobacter that is associated with urinary tract infections (UTI) is Citrobacter freundii, which accounts for (46.66%) of cases.

 

In Citrobacter freundii, the highest antibiotic susceptibility was observed in Levofloxacin (100%), followed by Ofloxacin (76.19%) and Amikacin (76.19%). The least antibiotic susceptibility was seen in Norfloxacin (50%) and Cephalothin (50%).

 

In Citrobacter diversus, the highest antibiotic susceptibility was observed in Levofloxacin (78.57%) followed by Ofloxacin (42.85%) and Amikacin (42.85%). The least antibiotic susceptibility was seen in Amoxyclav (0%).

 

In Citrobacter amalonaticus, the highest antibiotic susceptibility was observed in Levofloxacin (90%), followed by Ofloxacin (60%) and Amikacin (60%). The least antibiotic susceptibility was seen in Cefotaxime (9.09%).

 

In Citrobacter freundii, the highest susceptibility to antibiotics was observed with Polymyxin B (29.41%), followed by Meropenem (17.64%), Imipenem (17.64%), and Tigecycline (17.64%). The least susceptibility to antibiotics was seen with Cephalosporins.

 

In Citrobacter diversus, the highest susceptibility was observed to Polymyxin B (35.29%) followed by Tigecycline (23.52%). The least susceptibility was seen to Cephalosporins.

 

In Citrobacter amalonaticus, the highest susceptibility was observed for Polymyxin B (17.64%) and Tigecycline (17.64%), while the least susceptibility was seen for Cephalosporins.

 

 

Urinary tract infections (UTIs) are most common and can affect up to 10% of people at some point in their lifetime. It is important to detect and treat the infection early using the appropriate antibiotics to eliminate the pathogen, prevent urosepsis, and reduce the chances of kidney damage. [1]

 

Microorganisms belonging to the genus Citrobacter rarely cause infections in healthy individuals. However, they can lead to severe outbreaks in healthcare settings and are becoming increasingly antibiotic-resistant. Unfortunately, there are very few studies conducted in India on Citrobacter and its antibiotic sensitivity patterns and further studies are required.[12]

1.     Hiba Sami, Asfia Sultan, Meher Rizvi Et al, Citrobacter as a uropathogen, its prevalence and antibiotics susceptibility pattern, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India, Chrismed J Health Res 2017;4:23-26

2.     Poonam AR, Anil Kumar Bilolikar and Sukrutha Gopal Reddy, Prevalence and antimicrobial susceptibility pattern of Citrobacter species in various clinical samples in a tertiary care hospital, Krishna Institute of Medical Sciences, Telangana, India, J Med Sci Res. 2019;7(4):103-108

3.     Valencia R, Arroyo LA, Conde M, Aldana JM, Torres MJ, Fernández-Cuenca F, et al. Nosocomial outbreak of infection with pan-drug-resistant Acinetobacter baumannii in a tertiary care university hospital. Infect Control Hosp Epidemiol 2009;30:257-63

4.     Mohan S, Agarwal J, Srivastava R, Singh M. Observations on Citrobacter species from a tertiary care health centre with special reference to multidrug resistance and presence of CTX-M gene. Indian J Pathol Microbiol 2014;57:439-41

5.     Hanumantha S, Pilli HP. Catheter-associated urinary tract infection (CAUTI) incidence and microbiological profile in a tertiary care hospital in Andhra Pradesh. Indian J Microbiol Res. 2016;3:453-6.

6.     Clinical Laboratory Standards Institute (2010) Performance standards for antimicrobial susceptibility testing. Twentieth informational supplemented. In: CLSI document M100-S20. CLSI: Wayne, PA

7.     Abdulrasheed B. Abdu, Mohammed Kachallah, Kemebradikumo D. Pondei Et al, Antibiotic Resistance in Uropathogenic Citrobacter spp. Isolated from Internally Displaced Persons with Urinary Tract Infections in Internally Displaced Camps, Maiduguri, Niger Delta University, Maiduguri, Nigeria, Global Journals, 2019; 19(1): 2249-4618

8.     Navin Kumar Chaudhary, Antimicrobial Resistance among uropathogens with reference to extended spectrum β-lactamase production, July 2015

9.     Nandini MS, Madhusudan K. Bacteriological profile of catheter-associated urinary tract infection and its antimicrobial susceptibility pattern in a tertiary care hospital. Journal of Pharmaceutical Sciences and Research. 2016;8(4).

10.   Jaggi N, Sisodia P. Multidimensional supervision program to reduce CAUTI and its analysis to enable focus on labor cost-effective infection control in a tertiary care hospital. J Clin Diagn Res. 2012;6(8):1372–6.

11.   ) Verma S, Naik SA, Deepak TS. Etiology and risk factors of catheter-associated urinary tract infections in ICU patients. Int J Med Microbiol Trop Dis. 2017;3(2):65-70.

12.   Ashish Khanna, Nachatar Singh, Et al, The Antibiotic Resistance Pattern in Citrobacter Species: An Emerging Nosocomial Pathogen in a Tertiary Care Hospital, Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, Punjab, India, Journal of Clinical and Diagnostic Research, May 2012, 6(4): 642-644