ArchiveShiraz E-Med of J .SID 2020 April; 21(4):e92018. doi: 10.5812/semj.92018. Published online 2020 February 23. Research Article Identification of Bacteria Contaminating Musca domestica (Diptera: Muscidae) Collected from Animal Husbandries Majid Kababian 1, 2, Ehssan Mozaffari 1, Kamran Akbarzadeh 1, Razieh Shabani Kordshouli 1, 2, Abedin Saghafipour 3, * and Saeed Shams 4 1Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2Students’ Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran 3Department of Public Health, Cellular and Molecular Research Center, Faculty of Health, Qom University of Medical Sciences, Qom, Iran 4Cellular and Molecular Research Center, Qom University of Medical Sciences, Qom, Iran *Corresponding author: Department of Public Health, Faculty of Health, Qom University of Medical Sciences, Qom, Iran. Email: abed.saghafi@gmail.com Received 2019 April 07; Revised 2020 January 18; Accepted 2020 January 24. Abstract Background: House flies (Musca domestica L.) may mechanically transmit many microorganisms to humans. Objectives: To identify bacteria contaminating Musca domestica (Diptera: Muscidae) collected from animal husbandries in province of Qom, Iran in the year of 2019. Methods: In the cross-sectional study, house flies were captured by plastic water bottle fly traps and insect nets from four districts of the Qom Province and were immediately transferred to the Department of Medical Entomology, School of Public Health in ster- ile glass containers, individually. The bacterial isolation of the surface and gut contents of the flies were separately performed by biochemical methods. To confirm Salmonella spp. and Shigella spp., antigen-antibody agglutination reactions were carried out by specific antisera. Results: A total of 23 bacterial species were identified from 160 house fly external surfaces and/or digestive tract were isolated. The most frequently isolated bacteria from the external body and the digestive tract of 160 flies were E. coli (73.8%) and P. aeruginosa (100%), respectively. The most frequently isolated bacteria were P. aeruginosa, Salmonella serogroup D, S. dysenteriae, E. coli, C. freundii, S. aureus, and S. epidermidis. Conclusions: House flies are important in the mechanical transmission of a different range of the pathogens. In addition, because of the geographical features of Qom and isolated pathogens, it seems that the possibility of mechanical disease transmission by the flies can be increased. Keywords: Animal Husbandries, Bacteria, Muscidae, Musca domestica 1. Background mission of pathogens to humans, they can transmit sev- eral pathogens to their food and and environment because Flies are a large group of insects that are classified in of their behavior, nutrition, and the power of flight and the order Diptera and sub-order Cyclorrhapha or Musco- rapid displacement (6,7). These insects contribute to the morpha (1). These insects have a high species diversity mechanical transmission of many pathogens to humans, and about 150000 of their species have been identified especially in warm seasons. They are capable of trans- and described in 158 families. Of these species, 285, 1500, mitting more than 100 microorganisms of viral, bacterial, 2500, and 5000 species belong to Fanidae, Calliphoridae, and parasitic pathogens, such as poliovirus, hepatitis A Sarcophagidae, and Muscidae families, respectively (2,3). virus (HAV), hepatitis D virus (HDV), Chlamydia trachoma- The medically important flies, in terms of close coexis- tis, Coxiella burnetii, Cholera spp., Salmonella spp., Listeria tence with humans and their dependence on human habi- spp., Streptococci spp., Staphylococci spp., Shigella spp., Enta- tats, are known as domestic or synanthropic flies (4). They moeba, Giardia, nematodes, and eggs of some tapeworms are also often called “Filth flies”; they include four species through the hair, mouthparts, legs, vomitus, and feces on of Muscidae, Fanidae, Calliphoridae, Sarcophagidae fam- foods. In addition, they can transmit some food-borne dis- ilies, and some similar flies (5). Flies are diurnal insects, eases to humans (8). On the other hand, the larvae of some which often live in and around the human environment. flies can act as obligatory and facultative parasites of the Although they are not major biologic vectors in the trans- Copyright © 2020, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original workwww.SID.ir is properly cited. Archive of SID Kababian M et al. vertebrate body tissues and cause myiasis in humans and 3.3. Ethical Considerations animals (9). Previous studies have shown that the diges- tive tracts and the external body surfaces of the house flies This study received financial support from the Deputy (hairs, mouthparts, legs, vomitus, and feces) are contam- of Research, Qom University of Medical Sciences, Iran. inated with many human pathogens. Musca domestica is Ethical clearance was earned from the Qom University of more important due to the fact that it coexists with hu- Medical Sciences, Iran (project no.: 95793, code of ethics: mans (8). Animal husbandry in the rural areas of the Qom MUQ.REC. 1395.156). Province is a major occupation, and nearly 20000 house- holds are involved in livestock breeding. On the other 3.4. Bacterial Cultures of Surfaces and Gut Contents of the hand, the province has a plain and desert condition in House Flies terms of geologic pathology and has a warm and dry cli- mate. The production of animal wastes in hot weather From each region, 20 house flies were individually eval- conditions provides good breeding places for flies and the uated. First, for the isolation of the bacteria from the exter- early completion of their life cycle that can result in the nal body of the flies, each one was poured in two tryptic generation of the flies. soy broths (Merck, Germany). The media were mixed gen- tly for five minutes, which resulted in the bound bacteria 2. Objectives on the external surface of the insect to be released into the medium. Next, the sampled flies were transferred to new Therefore, this study was conducted to determine the tubes to be disinfected by 70% alcohol for two minutes, fol- bacteria contaminating Musca domestica (Diptera: Musci- lowed by being washed by sterile normal saline. Then, they dae) collected from animal husbandries in the province of were dissected under the stereomicroscope by an entomol- Qom, Iran, for the year 2019. ogist and their digestive tracts were completely inoculated in two tryptic soy broths. Media were incubated at 37°C for 24 h (each of the media was incubated separately in ~ 5% 3. Methods CO2 for fastidious bacteria). 3.1. Study Sites 3.5. Isolation and Detection of the Bacteria The Qom province is geographically located in the cen- ter of Iran (between 50 to 52 degrees east and 34 to 35 de- For isolating both Gram-negative and Gram-positive grees north) (Figure 1). It has one urban area and five ru- bacteria, subculture from tryptic soy broth was done sepa- ral areas. Due to low altitude, small rainfall, inappropriate rately on blood agar, chocolate, eosin methylene blue agar climate and saline lands, it is a part of the central desert of (EMB), hektoen enteric agar (HEA), xylose lysine deoxy- Iran. The Qom Province has a semi-desert climate and its av- cholate (XLD), lysine iron agar (LIA), salmonella-shigella erage annual rainfall is less than 100 mm, which is mainly agar (SSA), and mannitol salt agar (Merck, Germany). The in autumn and winter. The rainfall in the warm seasons, media were incubated at 37°C for 24 h in ~ 5% CO . First, especially in summer, is less than this amount (10). There- 2 suspected colonies were evaluated by Gram staining. Then, fore, it seems that the climatic and environmental factors a collection of the biochemical test was carried out for are very suitable for the development of flies, especially Gram-negative bacteria, such as catalase, oxidase, ortho- house flies (11). nitrophenyl-β-galactoside (ONPG), sulfide indole motility (SIM), methyl red (MR)/voges-proskauer (VP), citrate, ure- 3.2. Flies Collection ase, nitrate, oxidation/fermentation (OF), and fermenta- To collect flies, one village and one urban texture were tion of carbohydrate tests e.g. glucose, lactose, mannitol, selected from each district; then, two animal husbandries sucrose, sorbitol, etc. The final confirmation of the Shigella were randomly chosen. They were sampled one time and spp. and Salmonella spp. was also done using specific an- a total of 160 flies were obtained. Capturing was done us- tisera (Difco, USA). In positive cases of Shigella spp. and ing a plastic water bottle fly trap (Figure 2) and insect net- Salmonella spp., an agglutination reaction was observed hashing (Figure 3). The captured flies were then put into between the antigen and antibody (12-14). Other biochem- sterile glass containers. Finally, the samples were sent to ical methods (e.g., esculin hydrolysis, DNase, coagulase, the Department of Medical Entomology and Vector Con- catalase, hemolysis, growth on 6.5% NaCl, and suscepti- trol, School of Public Health, the University of Medical Sci- bility to optochin) were also used for the detection of the ences, Tehran, Iran. Gram-positive bacteria (15, 16). 2 Shiraz