Infections of Bones and Joints in Tropical Regions: Gram-Negative Bacilli Prevalence
Overview
This 6-year retrospective study at Guadeloupe University Hospital found Gram-negative bacilli (GNB) to be the predominant pathogens in bone and joint infections (BJIs) in a tropical setting, representing 41% of isolates. The study highlights significant resistance patterns, including AmpC β-lactamase–producing Enterobacterales and Pseudomonas aeruginosa, which impact empirical antibiotic choices.
Background
Bone and joint infections encompass a range of conditions such as native septic arthritis, osteomyelitis, and prosthetic joint infections, requiring multidisciplinary management and effective antibiotic therapy. Empirical treatment guidelines based on mainland France data may not be applicable in tropical regions like the French West Indies due to distinct pathogen profiles and resistance patterns. Prior studies in Guadeloupe and the Caribbean have noted a high prevalence of resistant Gram-negative bacilli, complicating antibiotic management. This study aimed to characterize the microbial epidemiology and resistance patterns of BJIs in a tropical tertiary care center to inform empirical treatment.
Data Highlights
Infection Type
Number of Cases
% with ≥1 GNB
Native Septic Arthritis
88
31%
Spondylodiscitis
27
33%
Prosthetic Joint Infections
71
38%
Osteosynthesis-Associated Infections
103
47%
Osteomyelitis
23
52%
Among 449 isolates, GNB accounted for 41%, including 13% AmpC β-lactamase–producing Enterobacterales and 9% Pseudomonas aeruginosa. Methicillin-resistant Staphylococcus aureus represented 3% of isolates.
In vitro adequacy of antibiotics in native septic arthritis: cefazolin 74%, cefepime and piperacillin-tazobactam 92%. In osteosynthesis-associated and prosthetic joint infections, cefazolin adequacy ranged 48%-68%, third-generation cephalosporins 62%-75%, cefepime 79%-80%, and piperacillin–tazobactam 80%-86%.
Key Findings
Gram-negative bacilli were the predominant pathogens in BJIs in this tropical setting, comprising 41% of isolates.
AmpC β-lactamase–producing Enterobacterales and Pseudomonas aeruginosa were common GNB species identified.
GNB prevalence varied by infection type, highest in osteomyelitis (52%) and osteosynthesis-associated infections (47%).
Risk factors independently associated with GNB infection included history of bite/scratch wounds, contact with soil or vegetation, and infections located in the lower limbs.
Empirical antibiotic cefazolin showed limited in vitro adequacy, especially in prosthetic and osteosynthesis-associated infections, compared to broader-spectrum agents like cefepime and piperacillin-tazobactam.
Findings suggest current empirical treatment guidelines based on temperate region data may be suboptimal in tropical BJIs.
Clinical Implications
Clinicians managing BJIs in tropical regions should consider the high prevalence of Gram-negative bacilli and their resistance patterns when selecting empirical antibiotics. Broader-spectrum agents such as cefepime or piperacillin-tazobactam may provide better initial coverage than cefazolin, particularly in prosthetic and osteosynthesis-associated infections. Local surveillance data are essential to guide appropriate empirical therapy and improve patient outcomes.
Conclusion
This study underscores the prominent role of Gram-negative bacilli in tropical bone and joint infections and highlights the need to adapt empirical antibiotic strategies to regional microbial epidemiology and resistance profiles. Implementation of local surveillance systems is crucial to optimize treatment.
References
SPILF Guidelines and Regional Epidemiology Studies
Guadeloupe University Hospital BJI Study 2019-2024
