Biofilm formation
capacity and Carbapenem-resistance in Acinetobacter-calcoaceticus-baumannii
isolated from inpatients in
a Tertiary Care Hospital in Nepal
Shova
Bhandari1, Milan Kumar Upreti1, Khadga Bikram Angbuhang1,
Basudha Shrestha2, Upendra Thapa Shrestha3 *
1GoldenGate International College, Battisputali, Kathmandu Nepal
2Kathmandu Model Hospital, Kathmandu, Nepal
3Central Department of Microbiology, Tribhuvan University,
Kirtipur, Kathmandu, Nepal
*Corresponding author: Upendra Thapa Shrestha, Assistant Professor, Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal, Email: upendrats@gmail.com / upendra.thapashrestha@cdmi.tu.edu.np
ABSTRACT
Objective: Acinetobacter calcoaceticus-baumannii complex (ACBC), as an
emerging global burden to various clinical infections, has a huge problem in
empirical therapy due to the increasing resistance to the majority of
antibiotics. The ability of biofilm formation added to its antimicrobial
resistance and helped its persistence and survival in the environment. To
associate biofilm formation with carbapenem resistance, a hospital-based cross-sectional
study was carried out from February
2020 to August 2020 at Kathmandu Model Hospital, Kathmandu, Nepal. ACBC was
identified from the clinical samples following standard Microbiological
procedures. A modified Kirby-Bauer disk diffusion method was performed to assay
the antibiotic susceptibility testing of ACBC isolates to various antibiotic
classes. A quantitative adherence assay was used to determine the biofilm assay.
A conventional Polymerase Chain Reaction (PCR) method was used to find the
targeted biofilm-related genes, Bap, csuE, and blaPER1 using specific primers.
Results: Out of 665
different clinical samples, bacterial growth was observed in 281 (42.3%)
clinical samples. Of these, 32 (11.4%) isolates were identified as ACBC. Out of
32 ACBC isolates, 29 (90.6%) of which were carbapenem-resistant. All carbapenem-resistant ACBC isolates were
found to be sensitive to Polymixin B and Colistin. Out of 29 CR-ACBC, 17.2% of isolates
were resistant to Tigecycline. The majority of ACBC isolates (93.8%) were multidrug-resistant (MDR)
while 13 (40.6%) of isolates were extensively drug-resistant (XDR). A total of 31 ACBC
isolates were biofilm producers, out of which 2 were strong biofilm producers
followed by 8 moderate, and 21 were weak biofilm producers. The occurrence of
biofilm-forming genes; Bap, csuE, and blaPER1 genes were found to be 65.6%, 65.6%, and
56.3% respectively among ACBC clinical isolates. A significant association was
observed between carbapenem resistance, biofilm formation, and biofilm-related
genes.
Conclusion: The higher rate of MDR and XDR ACBC isolates
associated with biofilm formation in the study alarms the ACBC-related
infection in clinical settings among inpatients. The hospital environment and
clinical equipment are potential sources of biofilm-forming isolates. Hence,
the effective sterilization of clinical equipment and hospital environment are
utmost and a strong policy should be made to prescribe the proper antibiotic
based on antibiogram profile to fight against an emerging threat of ACBC
infections.
Keywords: Acinetobacter
baumannii, Biofilm, Carbapenem-resistant, Biofilm related genes; Bap, csuE,
and blaPER1
Citation: Bhandari, S., Upreti, M.K., Angbuhang, K.B. et al. Biofilm formation capacity and Carbapenem-resistance in Acinetobacter-calcoaceticus-baumannii isolated from inpatients in a tertiary care hospital in Nepal. BMC Res Notes 18, 225 (2025).
DOI: https://doi.org/10.1186/s13104-025-07211-5
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