Intestinal Colonization by Campylobacter jejuni, Clostridium difficile, and Clostridium perfringens among Commensal Rattus norvegicus in the Urban Areas of Tehran, Iran

Background

Rattus norvegicus (R. norvegicus) population plays a significant role in the spread of numerous diseases in urban environments. The present study is aimed at investigating the presence of Campylobacter jejuni (C. jejuni), C. coli, Clostridium difficile (C. difficile), C. difficile toxigenic, and C. perfringens in R. norvegicus captured from urban areas of Tehran, Iran.

Methods

From October 2021 to October 2022, 100 urban rats were trapped in 5 different districts of Tehran, Iran. The genomic DNA was extracted from fecal samples, and the presence of C. jejuni, C. coli, C. perfringens, and C. difficile species was evaluated using PCR assay. Moreover, PCR was used to assess the toxicity of C. difficile isolates.

Results

Overall, 30% (n = 30/100) of fecal samples were positive for zoonotic pathogens. Based on the PCR on hippuricase (hipO), glycine (gly), CIDIF, and phospholipase C (plc) genes, C. perfringens and C. difficile were isolated from 18.2% (n = 14/77) and 5.2% (n = 4/77) of male rats. The highest frequency of C. perfringens and C. jejuni was 25% (n = 5/20) related to the south of Tehran. Toxigenic C. difficile was not detected in all regions.

Conclusion

According to the findings, rats are the main reservoirs for diseases. Therefore, rodent control coupled with the implementation of surveillance systems should be prioritized for urban health.

Detection and distribution of zoonotic pathogens in wild Norway rats (Rattus norvegicus) from Tehran, Iran

This is the first study on the prevalence of vector-borne zoonotic pathogens found in Rattus norvegicus (R. norvegicus) in urban areas of Tehran, Iran. Serological tests were used to detect IgG antibodies against Coxiella burnetii (C. burnetii) and Rickettsia spp. using a commercial qualitative rat ELISA kit. The frequency of Streptobacillus moniliformis (S. moniliformis) and Bartonella spp. was determined using a conventional PCR method. Molecular detection and characterization of Leptospira spp. were conducted using TaqMan real-time PCR based on lipL32 gene and SecY typing methods. A total of 100 R. norvegicus rats were collected from five regions in Tehran, Iran, and investigated to determine their zoonotic pathogens. S. moniliformis and Bartonella spp. were detected in 23 of 100 (23%) and 17 of 100 (17%) R. norvegicus populations, respectively. The highest prevalence of S. moniliformis and Bartonella spp. with similar frequency rates (n = 6/20; 30%) was seen among the R. norvegicus rats captured from the northern and southern parts of Tehran, respectively. Seroreactivity against C. burnetii and Rickettsia spp. was detected in 4% and 1% of R. norvegicus, respectively. C. burnetii. was identified only in one rat captured from the eastern part of Tehran. Results showed that Leptospira spp. was detected only in two rats, collected from the southern part (n = 2/20; 10%) of Tehran. The secY typing method identified two different Leptospira species including L. interrogans and L. kirschneri. The results showed that urban rats might play an important role in transmission of zoonotic pathogens to humans.