The alarming discovery of houseflies in hospital wards has revealed a potential threat to patient safety, as these insects can pick up infections from faeces and spread them to patients, surfaces, and food. Researchers have found that flies in Nigerian hospitals are carrying bacteria resistant to key antibiotics, highlighting the need for a multi-faceted approach to tackle antimicrobial resistance.
Flies may pick up infections from faeces, which they eat, then spread them to patients, hospital surfaces and food, researchers say.
Houseflies are one of the most common insects found in households worldwide.
They can be identified by their grayish or yellowish color, with a distinctive black stripe running along their back.
Houseflies have a short lifespan of around 15-30 days and can reproduce quickly, with females laying up to 150 eggs at a time.
These flies are attracted to decaying matter, garbage, and human waste, making them a significant nuisance in homes and public spaces.
Scientists in Nigeria have found that houseflies in hospitals carry bacteria resistant to some key antibiotics, including those used only as a last resort. This is a worrying development, especially considering the global threat posed by antimicrobial resistance (AMR). According to forecasts, AMR could kill more than 39 million people before 2050.
Antimicrobial resistance (AMR) occurs when bacteria, viruses, fungi, and parasites adapt to become resistant to antimicrobial agents such as antibiotics, antivirals, and antifungals.
This can lead to reduced effectiveness of treatments, increased morbidity, and mortality rates.
According to the World Health Organization (WHO), AMR is a major global health threat, responsible for over 700,000 deaths annually.
In the United States alone, AMR causes approximately 2 million illnesses and 23,000 deaths each year.
Researchers from the Ineos Oxford Institute for antimicrobial research worked with Nigerian scientists to collect 1,396 flies from eight hospitals in six cities. The tests revealed that the flies were carrying 17 different species of bacteria, including Staphylococcus aureus, a common cause of hospital-acquired infections. A large proportion of the bacteria sampled had genes linked to antimicrobial resistance.
While the study cannot prove that the flies were spreading the bacteria, Dr Chioma Achi, the project lead and co-author of the paper, said it was a ‘very worrying’ indicator. The findings suggest that flies could be vectors for antimicrobial resistance in hospitals, particularly in tropical low- and middle-income countries where they are abundant.
Houseflies are often overlooked as disease carriers, but they can transmit a range of pathogens.
According to the World Health Organization (WHO), houseflies can carry over 100 different types of bacteria, viruses, and parasites.
These include Salmonella, E. coli, and Shigella, which can cause food poisoning and other gastrointestinal illnesses.
Houseflies also spread diseases like dysentery, cholera, and typhoid fever.
In some cases, they can even transmit parasitic worms.
The WHO estimates that houseflies are responsible for the transmission of over 20% of all diarrheal diseases worldwide.
Flies are coprophagic – they eat faeces, manure, and other decaying matter. When an infected person passes their infection through their faeces, flies can pick up the bacteria and spread them to hospital surfaces, food, and environments that people touch.
Dr Kirsty Sands, scientific lead at the Ineos Oxford Institute for antimicrobial research, said the findings imply that flies circulating in hospital wards could pose a threat to patients who are vulnerable to infection during their stay. Flies commonly land on patients, which increases the risk of infection transmission.
Nigeria ranks 20th out of 204 countries for AMR death rates, with 263,400 deaths linked to AMR in 2019. The study highlights the need to consider the connection between human and animal environments in order to tackle the problem of AMR.
The team is planning further research to find out whether insect control methods, such as window screens and bed nets, can lower rates of AMR in hospitals. This study serves as a pilot for a larger multi-country study on insects and AMR in hospitals.
