Seasonal Dynamics of Gram-Negative Bacterial Infections

Seasonal fluctuations in the incidence and severity of infections caused by Gram-negative bacteria have been increasingly documented worldwide. Multiple studies have reported peaks in bloodstream, urinary tract and device-associated infections during warmer months, whereas resistance to certain agents may rise during cooler periods. Climatic variables such as ambient temperature, humidity and precipitation appear to influence both bacterial growth and gene transfer, while host susceptibility may vary with seasonal changes in immune function and skin or gut microbiome composition. The interplay of environmental drivers, pathogen adaptation and healthcare practices underpins observed oscillations in key opportunistic pathogens including Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. Understanding these dynamics has direct implications for infection surveillance, antimicrobial stewardship and the timing of prevention interventions in both community and hospital settings.

Research from Nature Portfolio

A comprehensive cohort analysis of central line-associated bloodstream infections across over one hundred hospitals revealed that the incidence of Gram-negative infections approximately doubled during the summer months compared with winter. Peak rates occurred in July and August, with a 2.5-fold rise relative to trough periods. In contrast, Gram-positive line-associated infections exhibited only modest seasonality. Statistical modelling linked each 5 °C increase in mean ambient temperature to a 30 % rise in Gram-negative infection rates and every 10 % increase in humidity to a 23 % rise. These findings underscore the need to account for climatological factors when designing surveillance systems and preventive trials for device-associated infections.

Seasonal Dynamics of Gram-Negative Bacterial Infections publication trend

The graph below shows the total number of articles in seasonal dynamics of gram-negative bacterial infections across all publications each year (not limited to Nature Index journals).

Technical terms

Gram-negative bacteria: Bacteria characterised by an outer membrane rich in lipopolysaccharide and a thin peptidoglycan layer, often associated with intrinsic antibiotic resistance mechanisms.

Seasonality: Recurring fluctuations in disease incidence or biological processes that align with environmental cycles such as temperature and humidity changes across the year.

Carbapenemase: A β-lactamase enzyme capable of hydrolysing carbapenem antibiotics, conferring high-level resistance to one of the last-line classes of β-lactams.

Meropenem: A broad-spectrum carbapenem antibiotic used to treat severe Gram-negative infections, including those caused by Pseudomonas and Acinetobacter species.

Plasmid conjugation: A mechanism of horizontal gene transfer whereby plasmids carrying resistance determinants are transferred between bacteria via direct cell-to-cell contact.

References

1. Effect of Temperature on Carbapenemase-Encoding Plasmid Transfer in Klebsiella pneumoniae. Microorganisms (2024).
2. Seasonal meropenem resistance in Acinetobacter baumannii and influence of temperature-driven adaptation. BMC Microbiology (2024).
3. Gram-negative central line-associated bloodstream infection incidence peak during the summer: a national seasonality cohort study. Scientific Reports (2022).