Department of microbiology, Dr. S.N. medical college Jodhpur (Rajasthan)
Aims & Background: Antimicrobial resistance (AMR) has become an emerging global health challenge now a day. Enterococci are opportunistic pathogens and are responsible for various types of infections. The growing clinical importance of these organisms is associated with their ability to show resistance to various types of antibiotics. Thus this study was planed to detect the prevalence of Vancomycin Resistant Enterococci (VRE) in different clinical isolates. Materials and Methods: This observational study was carried out on 550Enterococci isolates in Department of Microbiology, Dr S N Medical College, Jodhpur. Specimens were processed according to standard procedures.Inoculation was done on blood agar and MacConkey agar. Additionally, chocolate agar was use for CSF specimens. Identification of isolates wasbased on colony morphology, Gram’s stain appearance and a negative catalase reaction with growth on bile esculin agar. Further subspecies were identified based on their biochemical profiles. Final confirmation of species was done by Vitek 2 system. Kirby Bauer disk diffusion method is used to find out phenotypic resistance patterns among all isolated enterococci Results:Out of 550 isolates 457 (83.09%) were identified as E. faecalis, and 88 (16.0%) were E. Faecium and 5 were other species.Among the enterococcal isolates, enterococci were more sensitive to antibiotics vancomycin (94.0%) and linezolid (100%).6% of isolates (33 isolates) showed resistance towards vancomycin. The vancomycin-resistant strains of E. Faecalis (n=8)and E. Faecium (n=25)showed significant resistance to all the other antibiotics tested, except for linezolid.Conclusion: Findings of this study indicates a higher rate of vancomycin resistance (6%) in our region.This study shows geographical variations in the isolation and distribution of Enterococcus species, along with notable variation in vancomycin resistance. Clinical significance: Geographical variations should be considered as an adjunct in selecting antibiotic for treatment of enterococcal infections.
Antimicrobial resistance (AMR) has become a critical health challenge globally, largely because resistant pathogens complicate with treatment outcomes and contribute to prolonged illness, increased healthcare burden, and elevated mortality. Resistant bacteria increase the risk of complications, which can also lead to increase morbidity and mortality rate. Resistance is a natural biological outcome due to uses of antibiotics. Resistance is a natural biological outcome due to increase use of antibiotics. Increase and arbitrary use of antibiotics can lead to increase speed of emergence and selection of resistant bacteria. Enterococci are opportunistic pathogens and are responsible for various type of infections. They are prominent cause of urinary tract infections and can also cause intra-abdominal infections, pelvic sepsis, surgical wound infections, and bacteraemia. These are gram-positive cocci that naturally inhabit the environment (soil, plants, etc.), present as pairs or short chains. It is habitat as the normal human/animal gut flora and grows under facultatively anaerobic conditions1. Currently, there are around 50 different enterococcal species known. The human intestine usually has Enterococcus faecalis, and to a lesser extent, Enterococcus faecium. The growing clinical importance of these organisms is linked to their ability to acquire resistance to multiple classes of antibiotics. Antibiotics are antimicrobial agents that inhibit bacterial growth or can cause bacterial cell death. Vancomycin, a glycopeptides antibiotic, inhibits bacterial cell wall synthesis and can be used as a key agent against multidrug-resistant Gram-positive organisms2. However, widespread clinical use of vancomycin and extended-spectrum cephalosporins has contributed to the global emergence and spread of vancomycin-resistant Enterococci (VRE).
The World Health Organisation added VRE to its list of antibiotic-resistant bacteria that need urgent action in 2017. Global mortality rate ranges between 60 and 70%.3
According to the Centres for Disease Control and Prevention, VRE caused an estimated 54,500 infections and 5,400 deaths among hospitalised patients in the United States in 2017.4 Although the prevalence of VRE in India remains lower than that reported in some Western countries but the rate is increasing steadily.
Recognising the clinical significance of Enterococci and the rising incidence of VRE, the present study was conducted to determine the prevalence of Enterococcus species in various clinical samples and to assess the burden of vancomycin-resistant isolates in a tertiary care hospital in Western Rajasthan.
AIMS AND OBJECTIVES
To detect the prevalence of Vancomycin Resistant Enterococci (VRE) in different clinical isolates.
MATERIALS AND METHODS
Study Centre: The study was carried out on 550 isolates of Enterococci. It was an observation study conducted in the Department of Microbiology, Dr. S.N. Medical College, Jodhpur.
Inclusion Criteria: All the enterococcal isolates from clinical samples such as blood, urine, pus, wound swab, catheter tip and other body fluids.
Exclusion Criteria:All commensal enterococcal isolates from anatomical sites like the gastrointestinal tract and oral cavity were excluded.
Ethical approval: Ethical approval for this study was obtained from the Institutional Ethical Committee.
METHODS
Specimens were processed according to standard procedures. Direct microscopic examination was done using wet film for urine specimens and Gram’s stain for other specimens like pus and body fluids, looking for the presence of leukocytes and bacterial cells.5 Inoculation was done on blood agar and MacConkey agar. Additionally, chocolate agar was also inoculated for CSF specimens. Identification of isolates from clinical specimens was done based on colony morphology, Gram’s stain appearance and a negative catalase reaction with growth on bile esculin agar. Further subspecies were identified based on their biochemical profiles. Final confirmation of species was done by Vitek 2 system.6 Kirby Bauer disk diffusion method is used to find out phenotypic resistance patterns among all isolated enterococci. Phenotypic resistance to antibiotics, including vancomycin and teicoplanin, was determined using the Kirby-Bauer disk diffusion method on Mueller-Hinton agar, as recommended by CLSI guidelines.
RESULTS
During the study period, a total of 9655 samples were received, out of which 550 enterococci species were isolated. A majority of the isolates were from urine samples (79.45%) followed by Pus cultures (13.27%) and Blood samples (2.73%), Tracheal swab (2.18). Out of 550 isolates 457 (83.09%) were identified as E. faecalis, and 88 (16.0%) were E. faecium followed by E. avium 2(0.36%), E. durans 2(0.36%) and E. hirae 1(0.19%). Enterococcus faecalis was the most common species followed by Enterococcus faecium, E. Avium, E. Durans and E. Hirae. Only E. faecium and E. faecalis was further compared to other studies due to less prevalence of other species. Among the enterococcal isolates, enterococci were more sensitive to antibiotics vancomycin (94.0%) and linezolid (100%). Further, maximum resistance was observed for penicillin (61.45%), Doxycycline (63.45%), Ampicillin (55.82%), erythromycin (50.44%), and levofloxacin (39.27%). 24.54% of the isolates were resistant to high-level gentamycin (120 μg). A higher percentage of resistance to all antibiotics tested was noted among E. faecium strains, as compared to E. faecalis. In this study, 6% of isolates (33 isolates) showed resistance towards vancomycin. The vancomycin-resistant strains of E. Faecalis (n=8) and E. Faecium (n=25)showed significant resistance to all the other antibiotics tested, except for linezolid. Vancomycin-resistant E. faecium and E. faecalis showed total resistance to penicillin.
TABLE 1: Comparison of antibiotic resistance between VR E. faecalis and VR E. faecium
|
Antibiotics |
VR E. faecalis (n=8) |
VR E. faecalis (n=8) |
VR E. faecium (n=25) |
VR E. faecium (n=25) |
|
Resistance (number) |
Resistance (%) |
Resistance (number) |
Resistance (%) |
|
|
Penicillin |
8 |
100 |
25 |
100 |
|
Ampicillin |
8 |
100 |
24 |
96 |
|
Erythromycin |
5 |
83.33 |
3 |
100 |
|
Doxycycline |
8 |
100 |
25 |
100 |
|
Levofloxacin |
8 |
100 |
23 |
92 |
|
Gentamycin (HLG) |
5 |
62.5 |
20 |
80 |
|
Linezolid |
0 |
0 |
0 |
0 |
DISCCUSION
The prevalence of enterococci in clinical samples was 5.7% (550 isolates in 9655 sample received during study period). The findings of this study correlates with other studies across regions such as Gujarat, Kolkata, Lucknow, Ethiopia, and Saudi Arabia which reported a prevalence range of 1.46% to 85.8%.
In this study, the maximum number of samples, 119/550 (21.63%) was isolated from patients in >60-year age group. Carmeli etal7 also reported in their study that maximum patients were from >60-year age group. Our results are in contrast to study done by Gordon etal where 96% patients were from 10-20 year age group.
78.73% enterococci were isolated from IPD patients compared to OPD patients (21.27%). This can be due to prolonged stay in hospital and invasive procedures i.e. urinary catheterization, intravenous canula, endotracheal intubation. Further, a higher isolation rate (55.64%) was observed in male patients as compared to females. This could be due to more male patients being admitted to IPD during study period.
In this study, maximum enterococci were isolated from urine samples (79.45%) followed by pus samples (13.27%), blood samples (2.73%), tracheal swab samples (2.18%), fluid samples (0.91%), high vaginal swab samples (0.73%), CSF samples (0.55%) and central line samples (0.18%). These observations suggest that due to close proximity of urinary tract to anus, more Enterococci can do urinary tract infections. Gordon et al8 and Ruoff et al9also observed the maximum number of isolates from urine samples in their studies.
In our study among 550 Enterococci isolates, 94% isolates were sensitive to vancomycin. Vancomycin resistance was observed only in 33 (6%) isolates in which 25 isolates were VR E. faecium (75.76%) followed by 8 isolates of VRE. Faecalis (24.24%)
Our findings correlate with of Sivaradjy et al.10 in Pondicherry(2021)where they found 81.0% E. faecium and 8.0% E. faecalis Vancomycin resistance among Enterococci.
Studies across the world have shown increasing VRE prevalence over the past three decades, reinforcing the urgent need for surveillance. A increasing prevalence rate was reported in various studies from 0.3% by Gordon et al8. in 1992, and 38.5% in a study by Karmarkar et al11in 2004. In this study the prevalence of VRE was 6% with a notably higher proportion among E. faecium.
CONCLUSION
Enterococci are significant pathogens responsible for both hospital-acquired and community-acquired infections, with a growing impact on patient health. This study shows geographical variations in the isolation and distribution of Enterococcus species, along with notable variation in vancomycin resistance. This study demonstrates considerable variation in species distribution and antimicrobial resistance patterns within this region of Western Rajasthan. Our findings indicate a higher rate of vancomycin resistance (6%) in our region. Due to geographical variation in enterococcal species distribution as well as Vancomycin resistance, routine surveillance to detect Vancomycin-resistant enterococcus (VRE) promptly should be implemented. Furthermore, antibiotic stewardship programs should be strengthened to monitor and regulate the use of antibiotics the emergence of resistant strains.
CLINICALSIGNIFICANCE
In enterococcal infections, for selecting antibiotic for treatment of patient, geographical variations should be considered since the variation in species distribution and antimicrobial resistance patterns is also dependent on geographical area as observed in this study. Further, enhancing antimicrobial stewardship programs are essential for limiting further spread of resistant Enterococcal strains.
LIMITATIONS OF THE STUDY
Antimicrobial susceptibility testing (AST) results indicated resistance patterns consistent with vancomycin resistance, requires further genetic testing to confirm the presence of specific resistance genes.
CONFLICT OF INTEREST: There is no conflict of interest.
SOURCES OF FUNDING: No funding was received.
REFERENCES
Smita kulshrestha, Dr. Dheeraj Kumar Khandelwal, Durga prasad, Ritu gupta, Detection of Vancomycin-Resistant Enterococci from Clinical Specimens in a Tertiary Care Hospital in Western Rajasthan: An Observational Study, Int. J. of Pharm. Sci., 2026, Vol 4, Issue 3, 1281-1286. https://doi.org/10.5281/zenodo.18981330
10.5281/zenodo.18981330
