An Examination of Flying Insects in Seven Hospitals in the United Kingdom and Carriage of Bacteria by True Flies (Diptera: Calliphoridae, Dolichopodidae, Fanniidae, Muscidae, Phoridae, Psychodidae, Sphaeroceridae)

Abstract

Insects are efficient vectors of bacteria and in the hospital environment may have a role in spreading nosocomial infections. This study sampled the flying insect populations of seven hospitals in the United Kingdom and characterized the associated culturome of Diptera, including the antibiotic resistance profile of bacterial isolates. Flying insects were collected in seven U.K. hospitals between the period March 2010 to August 2011. The bacteria carried by Diptera were isolated using culture-based techniques, identified and characterized by antimicrobial susceptibility testing. A total of 19,937 individual insects were collected with Diptera being the most abundant (73.6% of the total), followed by Hemiptera (13.9%), Hymenoptera (4.7%), Lepidoptera (2.9%), and Coleoptera (2%). From Diptera, 82 bacterial strains were identified. The majority of bacteria belonged to the Enterobacteriaceae (42%), followed by Bacillus spp. (24%) and Staphylococcus spp. (19%). Less abundant were bacteria of the genus Clostridium (6%), Streptococcus (5%), and Micrococcus (2%). A total of 68 bacterial strains were characterized for their antibiotic resistance profile; 52.9% demonstrated a resistant phenotype to at least one class of antibiotic. Staphylococcus spp. represented the highest proportion of resistant strains (83.3%), followed by Bacillus spp. (60%) and Enterobacteriaceae (31.3%). Diptera were the predominant flying insects present in the U.K. hospital environments sampled and found to harbor a variety of opportunistic human pathogens with associated antimicrobial resistance profiles. Given the ability of flies to act as mechanical vectors of bacteria, they present a potential to contribute to persistence and spread of antimicrobial-resistant pathogenic bacteria in the hospital environment.

Diversity of Public Health and Forensic Important Flies Using Three Measures of Hill Numbers in Iran

“…As previously discussed, flies play a key role in the transmission of diseases and decomposition procedure of human corpse [1,9]. In this study, we used maggots to study diversity and succession patterns.…”

“…Diptera is one of the most important insects within the public health and forensic fields, due to their involvement in the transmission of diseases and also estimation of post mortem interval (PMI), PMI is the period of time between insects' establishment of corpses and their finding by the examiner [1,2]. Dipteran species are efficient vectors of over 100 pathogens, including bacteria, viruses, fungi, and parasites and they could have an important role in dissemination nosocomial infections [1,3]. In the term of forensics, flies may be used to determine the location of death, detection of the abuse of disabled people, identification of the deceased, and estimation of post mortem interval [4 -6].…”

“…Flies are the first colonizer of carcasses and their occurrence is in a predictable wave, hence, PMI could be estimated either by the study of insect's succession pattern of the carrion, or by tracing the development of the flies' larvae [2]. Each method could be affected by several factors such as; weather conditions, humidity, stage of decomposition, size and location of the carcass [1,4]. For intervals more than three days, medico-legal entomology was proven to be a more accurate tool in determining PMI [5,3].…”

Flies from a tertiary hospital in Rwanda carry multidrug-resistant Gram-negative pathogens including extended-spectrum beta-lactamase-producing E. coli sequence type 131

“…The detection of antibiotic-resistant E. coli from flies captured in a livestock facility was thus unsurprising [3]. Another study has shown that houseflies from hospitals in the UK carried different bacteria resistant to antibiotics [4]. We investigated if houseflies captured in a tertiary hospital in Rwanda carried clinically relevant MRGN pathogens.…”

“…Our results demonstrate that half of the flies in this tertiary hospital in Rwanda carried virulent MRGN pathogens including the pathogenic clonal E. coli lineage ST131. High pre-admission and even higher discharge rates at this facility [5] may suggest that a) patients and caregivers were the source of MRGN for the flies and b) that flies play a role in the transmission of antimicrobialresistant pathogens within clinics and in mirroring the burden of antimicrobial resistance [4] at that time. Even though the actual transmission of MRGN bacteria through flies to humans awaits verification, respective modelling results point strongly into this direction [11].…”