Predictors of Implant Failure in Orthopaedic Infections Due to Coagulase-Negative Staphylococci: The Impact of Biofilm and Proteolytic Enzymes –  A Prospective Observational Study.

Keshava Rao  Bolloju; Vadlamanu  Usha Rani; Ramesh  Kandimalla; Leena  Chacko

doi:10.51168/sjhrafrica.v6i6.1935

Authors

Dr. Keshava Rao Bolloju Associate Professor, Department of Orthopaedics, Government Medical College, Narsampet, Warangal District, Telangana, India
Dr. Vadlamanu Usha Rani Associate Professor, Department of Microbiology, Government Medical College, Narsampet, Warangal District, Telangana, India
Dr. Ramesh Kandimalla Associate Professor, Department of Biochemistry, Government Medical College, Narsampet, Warangal District, Telangana, India
Leena Chacko Senior Associate Scientist at Meso Scale Discovery, Rockville, MD, United States

DOI:

https://doi.org/10.51168/sjhrafrica.v6i6.1935

Keywords:

Coagulase-negative staphylococci, biofilm, orthopaedic implants, methicillin resistance, implant failure, antimicrobial resistance

Abstract

Background: Coagulase-negative staphylococci (CoNS), long considered low-virulence skin commensals, have emerged as significant pathogens in orthopaedic implant-associated infections. Their ability to form biofilms and produce proteolytic enzymes contributes to chronic infection, antimicrobial resistance, and implant failure.

Objectives: To evaluate the microbiological and biochemical characteristics of CoNS isolates from orthopaedic implant infections, assess antimicrobial susceptibility, and identify predictors of adverse clinical outcomes, including implant removal and delayed bone healing.

Methods: This prospective observational study enrolled 120 patients with suspected implant-associated infections over two years. Sonication fluid and periprosthetic tissue cultures were performed, and isolates underwent species identification, antimicrobial susceptibility testing, and assessment of biofilm formation, exopolysaccharide production, and protease activity. Clinical outcomes were recorded over a six-month follow-up. Statistical analyses included multivariate logistic regression and correlation studies.

Results: CoNS were isolated in 48 cases (40%), predominantly Staphylococcus epidermidis (70.8%). Methicillin resistance was present in 68.7% of isolates, with high rates of multidrug resistance to erythromycin (79.1%), ciprofloxacin (64.5%), and clindamycin (60.4%). Strong biofilm production was observed in 79.1% of isolates and was significantly associated with implant removal (73.6% vs. 30%; p=0.004), prolonged antibiotic therapy (mean 6.4 vs. 4.2 weeks; p=0.001), and delayed union (44.7% vs. 20%; p=0.03). Multivariate analysis identified strong biofilm production (OR 4.25; p=0.015) and higher proteolytic enzyme activity (OR 1.92; p=0.040) as independent predictors of implant removal.

Conclusions: CoNS are major contributors to orthopaedic implant failure, primarily driven by biofilm-related virulence and proteolytic activity rather than methicillin resistance alone. These findings highlight the need for early microbiological diagnosis and biofilm-targeted interventions.

Recommendations: Clinicians should incorporate implant sonication and biofilm assessment into routine diagnostic protocols and consider prolonged antimicrobial therapy and early surgical intervention in cases with strong biofilm-producing CoNS. Future research should focus on molecular characterization of virulence factors and anti-biofilm therapies to improve treatment outcomes

Author Biographies

Dr. Keshava Rao Bolloju, Associate Professor, Department of Orthopaedics, Government Medical College, Narsampet, Warangal District, Telangana, India

is a distinguished orthopaedic surgeon currently serving as an Associate Professor in the Department of Orthopaedics at Government Medical College, Narsampet, Telangana. He also functions as a National External Assessor for the National Quality Assurance Standards (NQAS) Programme, contributing to the quality assessment and accreditation of government hospitals across India. Previously, he held the position of Assistant Professor at MGM Hospital and Kakatiya Medical College, Warangal, where he contributed extensively to both clinical services and academic mentorship. Dr. Bolloju earned his Bachelor of Medicine and Bachelor of Surgery (M.B.B.S.) from Kakatiya Medical College, Hanumakonda, Warangal (2000–2005), followed by a Master of Surgery (M.S.) in Orthopaedics from the Prathima Institute of Medical Sciences, Karimnagar, Telangana (2012–2015). With over a decade of dedicated service spanning primary, secondary, and tertiary healthcare settings, he has demonstrated exceptional proficiency as a treating physician, medical officer, and programme officer for national health initiatives throughout the erstwhile state of Andhra Pradesh and present-day Telangana. Renowned for his surgical acumen, Dr. Bolloju possesses advanced expertise in managing complex trauma, performing joint reconstructions, and employing Ilizarov’s technique of external fixation for limb salvage and correction of severe deformities. His surgical repertoire encompasses the management of polytrauma, open fractures, neglected injuries, and deformity corrections, delivered with a patient-centred approach that emphasises functional recovery and quality of life. He has been instrumental in training and mentoring undergraduate and postgraduate medical students, integrating evidence-based practices into orthopaedic education. His primary research interests include trauma care protocols, general orthopaedics, and innovations in external fixation techniques. Dr. Bolloju has organised numerous outreach health camps, delivering specialised care to individuals with disabilities and facilitating the issuance of disability certificates to support their social and economic empowerment. He has authored and co-authored multiple research publications in reputable indexed journals, including EMBASE, SCOPUS, and DOAJ, reflecting his sustained commitment to advancing orthopaedic science and improving patient care. His ORCID is https://orcid.org/0009-0007-9372-8955.

Dr. Vadlamanu Usha Rani, Associate Professor, Department of Microbiology, Government Medical College, Narsampet, Warangal District, Telangana, India

is an accomplished microbiologist with over 15 years of experience in diagnostic microbiology, antimicrobial resistance, and medical education. She earned her M.B.B.S. from Kakatiya Medical College, Warangal, where she was awarded University Distinctions in Pharmacology and Forensic Medicine. She subsequently completed her M.D. in Microbiology at Osmania Medical College, Hyderabad, ranking second in the NTR University final examinations. Dr. Usha Rani has held faculty positions at Kakatiya Medical College and currently serves as Associate Professor in the Department of Microbiology at Government Medical College, Narsampet. Her academic interests focus on infection control, antimicrobial stewardship, and the immunological diagnosis of infectious diseases. She has conducted pioneering research on doripenem susceptibility in Gram-negative bacilli and the early diagnosis of dengue infections using serological and molecular methods, for which she received the prestigious Bhaskaran Award. She has authored peer-reviewed publications in the Journal of Biomedical and Pharmaceutical Research, with her papers indexed in EMBASE, DOAJ, SCOPUS, and Index Copernicus. She has presented her work at numerous national conferences and contributed to advancing evidence-based practices in microbiology. In addition to her research contributions, Dr. Usha Rani has been actively involved in teaching undergraduate and postgraduate students and has delivered training on hospital epidemiology and PCR techniques. She is committed to improving laboratory practices and infection control protocols and continues to mentor young clinicians and microbiologists. Her ORCID is https://orcid.org/0009-0000-4865-0932.

Dr. Ramesh Kandimalla, Associate Professor, Department of Biochemistry, Government Medical College, Narsampet, Warangal District, Telangana, India

is the I/c Head of Department and Associate Professor of Biochemistry at Government Medical College, Narsampet, Warangal, Telangana, India. He earned his doctorate in Biochemistry with a specialization in Neuroscience from the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, and holds over 17 years of research and teaching experience. Dr. Kandimalla has held positions at prestigious institutions including McGill University, Emory University, Oregon Health & Science University, Texas Tech University, and CSIR-IICT Hyderabad. His work focuses on neurodegeneration, Alzheimer’s disease, mitochondrial biology, and nanomedicine. He has authored over 100 peer-reviewed publications in high-impact journals, with an H-index of 47 and more than 10,000 citations. Dr. Kandimalla has received numerous accolades, including recognition as one of the World’s Top 2% Scientists in Neurology by Stanford University and awards from NASA and NIH. He also serves as an Associate Editor for Brain Research and as Guest Editor, Associate Editor for Frontiers journals. His contributions span research, clinical biochemistry, and medical education, advancing understanding of neurodegenerative diseases and innovative therapeutic strategies. His ORCiD is https://orcid.org/0000-0002-3313-4393.

Leena Chacko, Senior Associate Scientist at Meso Scale Discovery, Rockville, MD, United States

is an accomplished clinical laboratory scientist and researcher with over 18 years of experience spanning microbiology, immunodiagnostics, and bioanalytical science. She holds a Master of Science in Medical Microbiology from Kasturba Medical College, Manipal, and an MBA in Healthcare Management. Ms. Chacko is currently a Senior Associate Scientist at Meso Scale Diagnostics, where she leads projects developing and validating high-sensitivity immunoassays for biomarker detection, including assays critical for early Alzheimer’s disease diagnosis. Her work has contributed to multiple peer-reviewed publications in high-impact journals, covering areas such as altered glucose metabolism in Alzheimer’s, lipidomic biomarkers, CRISPR-Cas9 applications in neurodegeneration, and nanomedicines for diabetic nephropathy. Previously, she held senior laboratory roles in the United States, UAE, and India, where she gained extensive experience in microbiology, clinical diagnostics, and quality systems. Certified by the American Society for Clinical Pathology and licensed in multiple states and countries, Ms. Chacko is recognized for her expertise in assay development, molecular techniques, and clinical research that bridges laboratory innovation with patient care. Her contributions are widely regarded as advancing both scientific knowledge and clinical practice in neurodegenerative and metabolic diseases. Her ORCiD is https://orcid.org/0000-0002-0383-6925

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