Cockroaches could be spreading antimicrobial resistance: study
Scientists have linked these pests to serious food-borne viruses, making it imperative that households maintain high levels of hygiene. Scientists say that cockroaches could be helping to spread antimicrobial resistance (AMR) through their collection of microbes, such as bacteria, fungi and viruses that naturally live on and in their bodies, and their genes.
Cockroaches have long been considered disgusting and embarrassing, especially in the home. They are a common pest that infests homes and apartments, especially kitchens where food is spilled.
And now scientists have linked these pests to serious food-borne viruses, making it imperative that households maintain high levels of hygiene.
Scientists say that cockroaches could be helping to spread antimicrobial resistance (AMR) through their collection of microbes, such as bacteria, fungi and viruses that naturally live on and in their bodies, and their genes.
This, they believe, is facilitated by the fact that many cockroach species live in dense groups and have frequent contact, as do people living in urban environments.
According to the World Health Organization, AMR “occurs when bacteria, viruses, fungi and parasites no longer respond to antimicrobial medicines. As a result of drug resistance, antibiotics and other antimicrobial medicines become ineffective and infections become difficult or impossible to treat, increasing the risk of disease spread, severe illness, disability and death.”
Published in mSystems Journal
The results of the study, published in mSystems Journal, suggest that the numerous microorganisms residing on and within cockroaches, and potentially other organisms, may be contributing to the dissemination of antimicrobial resistance genes.
In the study, researchers introduced tetracycline, an antibiotic used to treat various bacterial infections, into the diet of Pycnoscelus surinamensis cockroaches – a highly social species that lives in close-knit groups. They then observed an increase in the prevalence of tetracycline resistance genes in bacteria living in the guts of the treated cockroaches.
The next step was to allow an untreated group of cockroaches to interact with the tetracycline-treated ones. After these interactions, the untreated cockroaches showed increased resistance to tetracycline, along with increased resistance in the soil bacteria in their enclosures. The level of resistance depended on the extent and frequency of interactions between treated and untreated cockroaches.
The results of the study show that the transmission of antimicrobial resistance (AMR) may not be solely due to the direct overuse of antibiotics. It suggests that animals with AMR genes in their microbiomes can interact with those without, potentially allowing AMR genes to be transferred between them. Further research in mammals is needed to validate these findings and extend the implications to humans.
Densely populated urban environments
"While cockroaches might not replicate the complexities of human or mammalian microbiomes, they offer a tractable, relevant and efficient system for studying the dynamics of AMR transmission, especially in the context of densely populated urban environments," the researchers said.
Another study published in the National Library of Medicine details that cockroaches have the potential to transmit pathogenic bacteria with antibiotic resistance.
“The night-time habits and behaviour of cockroaches may render them as a potential vector for a range of pathogenic microorganisms. Cockroaches can readily move from a contaminated environment and provide an opportunity for bacteria to contaminate the food, utensils, and food preparation areas,” says the study.
“Also, they forage readily on faeces, sputum, skin scrapings, other human debris, and diverse foodstuffs. Consumed bacteria can thrive in the cockroach’s digestive system, for at least a couple of months or even years. The bacteria can then be passed through its droppings,” the study says.
“Cockroaches depend on their wings, legs, and cuticles for grooming. This may increase the likelihood of direct contact with contaminated surfaces. Potential pathogens can be easily spread by contact between the contaminated cockroaches and food, eating utensils as well as drinking vessels.
Pathogenic bacteria
“The spread of potentially pathogenic bacteria could occur by cockroach regurgitation or faecal pellet deposition into human foodstuffs. Also, they expel portions of partially consumed food and drop faeces at intervals. They also release a smelly discharge from their mouths and glands. In general, the literature illustrates that due to their mobility and frequent contact with humans, they may be a vector of infections.”
Cockroaches have also been identified as carriers of various pathogenic bacterial agents. Depending on the species, they can lead to wound infections, diarrhoea, gastroenteritis and urinary tract infections, food poisoning, conjunctivitis, enteritis, gas gangrene, bacteraemia, urinary tract and wound infections, pneumonia and leprosy.
“The majority of these bacteria exhibit resistance to commonly used drugs, with antibiotic resistance posing a significant threat to public health in the current era. Consequently, the infestation of cockroaches should be regarded as a serious concern due to their potential role as reservoirs of antibiotic-resistant bacteria. A comprehensive review of existing research information would benefit researchers and the general community, offering a thorough understanding of the involvement of cockroaches in the transmission of human infections.”
