‘Cockroaches and other pests can carry multi-drug resistance genes’
In a study conducted by four researchers in three wards of Rajshahi Medical College Hospital (RMCH), it was found that cockroaches can carry and spread germs that can cause antibiotic resistance and multi-drug resistance among patients. The issue is so important that the World Heath Organization (WHO) has warned that antibiotic resistance is rising to dangerously high levels in all parts of the world. The research findings have been published in the May issue of ‘Journal of Scientific Research’ of Rajshahi University. M Saiful Islam, professor of the zoology department at the university and a member of the research team, talked to Prothom Alo’s Shameem Reza about their findings and some other related issues.
When did you start this research and what are the findings?
The experiments were conducted in July through December 2021. In a nutshell, the findings are: (1) A total of 52 bacterial isolates (26 from the cuticle and 26 from the gut) comprising 20 from Neuromedicine Ward (NMW), 18 from Orthopedic Ward (ORW) and 14 from Surgery Ward (SRW) of Rajshahi Medical College Hospital (RMCH) were used for biochemical analyses and diagnostic characteristics;
(2) Seven Gram-negative rod species namely, Escherichia coli, Klebsiella spp., Serratia marcescens, Salmonella spp., Pseudomonas spp., Enterobacter spp. and Proteus spp. were identified, of which E. coli and Klebsiella spp. were the most dominant bacteria;
(3) Serratia marcescens, Klebsiella spp. and Pseudomonas spp. were resistant to 55.6 per cent of the 18 commonly used antibiotics whereas Escherichia coli, Salmonella spp. Enterobacter spp. and Proteus spp. were sensitive to 50.0 per cent antibiotics;
(4) Overall, the antibiogram profile and multidrug resistant (MDR) pattern of the bacterial isolates from hospital samples revealed 52.3 per cent resistant, 42.1 per cent sensitive and 5.6 per cent mixed (intermediate) response towards the antibiotics under study.
In the research article you said this was about multi-drug resistance (MDR). Are MDR and antibiotic resistance the same or are there any subtle differences between the two?
Antibiotics are important drugs which help fight infections that are caused by microbes such as bacteria, fungi and viruses. So, simply put, antibiotic resistance refers to a phenomenon where microbes develop the ability to defeat the drugs designed to kill them. In other words, it means the microbes are not killed by the drugs, instead they continue to grow.
Multiple drug resistance or multi-drug resistance (MDR), on the other hand, is a type of antimicrobial resistance that is shown by a microbial species to at least one antimicrobial drug in three or more antimicrobial categories. However, of the MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics. For example, bacteria that resist treatment with more than one antibiotic are called MDR bacteria. These are found mainly in hospitals and long-term care facilities.
Infections with MDR bacteria are hard to treat since little or even no treatment options remain available to health service providers, who then have to use high-powered antibiotics that are more toxic to the patients and their environments.
Your research was conducted on cockroaches. Could any other pest be responsible for the proliferation of such MDR?
Certainly there are many other vectors that can carry MDR genes. Invertebrate pests like houseflies and mites, and vertebrate pests such as rodents (mice and rats) and cats could be the possible sources/reservoirs of such MDR microbes in the environment, such as hospitals, households and restaurants.
You mentioned research on MDR bacteria in several countries and a previous research in Dhaka. Is there any difference between the research conducted in Bangladesh in 2018 and your one? Could your findings be generalised in cases of other hospitals and urban environment in Bangladesh?
Yes, there exist a few contrasting differences between the studies reported earlier in the country from Chattogram (in 2016) and Dhaka (in 2016 and in 2018). In short, researchers in 2016 took samples of American cockroaches (P. americana) from restaurants and households of Chattogram City Corporation, and they identified a single species of bacteria (Staphylococcus spp.) which was tested against six antibiotics.
Whereas the researchers in 2016 collected cockroaches from dining halls of Dhaka University (DU), and Dhaka Medical College Hospital (DMCH), but they did not assess the antibiogram profiles of the bacterial isolates. (In simple terms, they did not assess how susceptible the strains of pathogens are to a variety of antibiotics.)
The researchers in 2018, however, used B. germanica from residential houses at Banani, two food restaurants at Mohakhali and a hospital (Shahid Suhrawardi Medical College Hospital). They identified 13 species of bacteria and analysed MDR profiles of the bacterial isolates against 24 antibiotic discs. But they did not proceed further for the genome sequencing of the MDR bacterial strains collected from the experimental cockroaches.
We are not sure though, but we would anticipate that our results represent a generalised picture of the MDR strains of bacteria carried by cockroaches in urban and rural healthcare facilities of the country.
What’s the ratio of MDR due to infection from pest-carried germs and under or overdose of medicine?
Sorry, we have not focused our study on the issue(s) you have raised here. Neither did we collect data on patients’ antibiogram profiles.
As per your findings, the surgery wards were relatively in a better condition than neuromedicine and orthopedic wards. How would you explain this?
You are perhaps right in recognising the fact that in comparison with other two wards, SRW not only had fewer bacterial isolates (14 out of 52 i.e., 27 per cent) but it also had fewer bacterial species (4 out of 7) as well. Here, we may only anticipate that compared to NMW and ORW wards, SRW is perhaps better maintained in terms of the hygiene and cleanliness. However, further research is needed before reaching to such a concrete conclusion.
One of your co-authors, S Parvin, is from the pathology department of RMCH. That means they are also now aware of the situation. But while talking to a media the director of RMCH said he is not aware of any such research.
Data of our experiment was collected by an MS (thesis) student (MS Akter, also the first author of the article), who took necessary the permission from the RMCH authorities before sampling cockroaches from the hospital wards. She was supervised by a faculty member (MK Mohanta) of the Department of Zoology, RU. S Parvin was a former MD student at the Department of Pathology, RMCH, and later transferred to Faridpur. Her assistance was sought for the biochemical/ pathological analyses of the isolates. So, the present authors had no contact/correspondence with the Director of RMCH.
Given the circumstances, we might speculate that the findings of the present research might have embarrassed him and perhaps he was reluctant to tarnish the reputation of the hospital by acknowledging the findings of the research paper.
Do you have recommendations to curb this rise in MDR due to germs carried by pests? Do you have any plans for further research?
Our findings suggest a two-way recommendation. Firstly, appropriate measures need to be taken to control or eradicate B. germanica and other cockroach and housefly species from patient care units; and secondly, indiscriminate and/or irrational uses of antibiotics need to be restricted/banned in both human and animal/livestock medical practices to prevent or reduce the emergence of MDR microbial species in the community.
Yes, currently we are progressing with a couple of future plans: (1) To complete genome sequences of MDR bacteria isolated from cockroaches in RMCH (this project is in progress in collaboration with the Department of Biology, University of Regina, Saskatchewan, Canada) and (2) to assess the presence/absence of MDR bacteria in B. germanica cockroaches from households (control group) as well as in the available vertebrate hosts/vectors such as rodents and cats from hospitals/health care facilities in the City.
What are your observations regarding the general state of research in Bangladesh?
The overall scenario of good and meaningful research in public and private sectors in Bangladesh is not very promising, principally because of the lack of consistent research funding and adequate laboratory facilities. Nonetheless, occasionally there are some brilliant research findings and their publications in world renowned journals are worth mentioning and encouraging for the dedicated researchers of the country.
is there anything else relevant to share?
There is very little or no incentive for the research teams/individuals in most of the institutions in Bangladesh. Private as well as public entrepreneurs of the country should come forward to promote good and meaningful research in various sectors of Bangladesh.