Antibiotic-resistant bacteria can hide inside macrophages without alerting the immune system

A new study has shown for the first time how the antibiotic-resistant bacteria Enterobacter can lie dormant in human cells without alerting the immune system

10 Mar 2025

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By hiding inside macrophages (a type of white blood cell in blood and tissue which is the first line of defence against microbes) Enterobacter lies dormant and does not stimulate any inflammatory responses, allowing it to escape the action of the few antibiotics that remain available for treating the infection.

Wellcome-Wolfson Institute for Experimental Medicine at Queen’s University Belfast

Enterobacter infections, including wound infections, urinary tract infections, gastroenteritis, meningitis, pneumonia and septicemia, are serious infections with a high mortality rate, even with appropriate treatment.

This breakthrough study could help to develop new ways to treat infected patients and clear Enterobacter infections more efficiently, leading to less deaths. 

This research was carried out at the Infection Biology Group of the Wellcome-Wolfson Institute for Experimental Medicine at Queen’s University Belfast by the Valvano Lab Research Team including Dr Georgiana Parau, Ms. Hannah Parks, Ms. Amy Anderson, and Dr Inmaculada Garcia-Romero.

Lead researcher on the study, Professor Miguel A. Valvano, Chair in Microbiology and Infectious Diseases from the Wellcome-Wolfson Institute for Experimental Medicine at Queen’s University Belfast, explains, “Despite extensive information on antibiotic resistance by Enterobacter species, very little is known about how these bacteria cause infection. Our new study has bridged this knowledge gap by showing for the first time that antibiotic-resistant isolates of Enterobacter species can survive inside human macrophages without being killed.

“The demonstration that Enterobacter isolates can hide inside macrophages has important clinical implications for the treatment of infected patients since antibiotics cannot reach the intracellular bacteria and the macrophages cannot easily remove them.” 

The research was funded by the Biotechnology and Biological Sciences Research Council. The study has been published in the Journal of Infection Diseases.

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MicrobiologyMicrobiology is the study of microorganisms including protists, prokaryotes, fungi, and, often, viruses. Microorganisms are a useful research tool as genetic vectors and, in immunology, for antibiotic susceptibility testing, cellular biology and genetics. Microorganisms commonly grow readily in incubators with microbial culture media; this can contain chromogenic supplements to differentiate between cell lines. Estimate your culture’s density of microorganisms with colony counters, or screen and select colonies for desirable clones with automated colony pickers. Additionally, equipment is available to monitor environments for the presence of microbes and identify with microbial identification instruments. Find the best microbiology products in our peer-reviewed product directory: compare products, check customer reviews and receive pricing direct from manufacturers.Infectious DiseaseInfectious disease diagnostics refers to the isolation and identification of causative agents, such as viruses, bacteria or fungi. Diagnostic tests include bacterial culture, microscopy, chemistry assays, molecular diagnostics and MALDI-TOF. Tests can be carried out in the laboratory or at the point-of-care.Antibiotic ResistanceAntibiotic resistance poses a significant threat to public health driving innovation and change through antibiotic stewardship efforts. Ongoing research and diagnostic efforts focus on new treatments and detection methods. Explore antibiotic resistance research and diagnostic tools in our peer-reviewed product directory; compare products, check reviews, and get pricing directly from manufacturers.MeningitisSepticemiaPneumonia