Salmonella serotypes isolated in geckos kept in seven collections in southern Italy

Virulence factors of Salmonella spp. isolated from free-living grass snakes Natrix natrix

Salmonellosis associated with reptiles is a well-researched topic, particularly in China and the United States, but it occurs less frequently in Europe. The growth of the human population and changes in the environment could potentially increase the interaction between humans and free-living reptiles, which are an unidentified source of Salmonella species. In this study, we sought to explore this issue by comparing the microbiota of free-living European grass snakes, scientifically known as Natrix natrix, with that of captive banded water snakes, or Nerodia fasciata. We were able to isolate 27 strains of Salmonella species from cloacal swabs of 59 N. natrix and 3 strains from 10 N. fasciata. Our findings revealed that free-living snakes can carry strains of Salmonella species that are resistant to normal human serum (NHS). In contrast, all the Salmonella species strains isolated from N. fasciata were sensitive to the action of the NHS, further supporting our findings. We identified two serovars from N. natrix: Salmonella enterica subspecies diarizonae and S. enterica subspecies houtenae. Additionally, we identified three different virulotypes (VT) with invA, sipB, prgH, orgA, tolC, iroN, sitC, sifA, sopB, spiA, cdtB and msgA genes, and β-galactosidase synthesised by 23 serovars. The identification of Salmonella species in terms of their VT is a relatively unknown aspect of their pathology. This can be specific to the serovar and pathovar and could be a result of adaptation to a new host or environment.

Cytotoxicity and Antimicrobial Resistance of Salmonella enterica Subspecies Isolated from Raised Reptiles in Beijing, China

BACKGROUND

Reptiles are asymptomatic carriers of Salmonella spp. Reptile-associated Salmonella infections have been noticed as a significant contributor to overall human salmonellosis. However, it remains unclear regarding the prevalence of reptile-associated Salmonella in China.

METHODS

Fecal and gastrointestinal mucosal samples were taken from 104 snakes, 21 lizards, and 52 chelonians and cultured on selective medium. The positive clones were validated and annotated by biochemical screening and multiplex PCR verification. In addition, the antibiotic resistance of identified Salmonella isolates was detected and followed by cytotoxic activity detection on human colon cells via co-culturation.

RESULTS

The overall prevalence of Salmonella in reptiles was 25.99%, with rates of 30.77%, 47.62%, and 7.69% in snakes, lizards, and chelonians, respectively. Further, all isolates showed variable drug-resistant activity to 18 antibiotics, of which 14 strains (30.43%) were resistant to more than eight kinds of antibiotics. More than half of isolated Salmonella strains were more toxic to host cells than the standard strain, SL1344. Whole genome sequencing (WGS) results showed that all lizard-associated strains belong to 4 serovar types, and 7 of them fall into the highly pathogenic serovars "Carmel" and "Pomona."

CONCLUSIONS

Our results highlight the potential threat of zoonotic salmonellosis from captive reptiles in the Beijing area of China.

Antimicrobial Resistant Salmonella in Chelonians: Assessing Its Potential Risk in Zoological Institutions in Spain

Salmonella is mostly noted as a food-borne pathogen, but contact with chelonians has also been reported as a source of infection. Moreover, high levels of antimicrobial resistance (AMR) have been reported in Salmonella isolated from wild and captive reptiles. The aim of this study was to assess the occurrence of Salmonella AMR carriage by chelonians admitted to two zoological institutions in Spain, characterizing the isolates to assess the Salmonella AMR epidemiology in wildlife. To this end, 152 chelonians from nine species were sampled upon their arrival at the zoological nuclei. Salmonella identification was based on ISO 6579-1:2017 (Annex D), isolates were serotyped and their AMR analysed according to the EU Decision 2013/652. Moreover, the genetic relationship of the isolates was assessed by pulsed-field gel electrophoresis (PFGE). Results showed 19% (29/152) of the chelonians positive to Salmonella, all of them tortoises. For all isolates, 69% (20/29) were resistant and 34% (10/29) multidrug-resistant (MDR) strains. PFGE clustered isolates according to the serovar, confirming a low genetic diversity. In conclusion, this study shows a high presence of MDR Salmonella strains in tortoises at their entry into zoological nuclei. This condition highlights the need to establish Salmonella detection protocols for the entry of animals into these centres.

Surveys on Exposure to Reptile-Associated Salmonellosis (RAS) in the Piedmont Region—Italy

Simple Summary

Reptile-associated salmonellosis (RAS), Salmonella infection (salmonellosis) in humans, is acquired through contact both directly with reptiles and indirectly with their environment. In Italy, like in other countries, reptiles have become popular pet animals, but epidemiological data about RAS are not collected. To fill this gap, surveys to estimate the presence and frequency of RAS and human exposure were carried out in Piedmont, a Northern-Italian region. Two studies were conducted among patients with sporadic salmonellosis (i.e., not linked to foodborne outbreaks): the first, restricted to a big city hospital, showed a prevalence of RAS of 7%, and the second, extending to the population affected by sporadic salmonellosis across all the region, showed a prevalence of 3%. In addition, an ocular survey taken in public places displaying reptiles detailed possible exposure through direct and indirect contact and a questionnaire survey that collected data from the general population, including reptile owners, revealed that preventive measures are not always known or applied. These results confirmed that RAS in Italy is present and constitutes a proportion of the human salmonellosis cases in line with the percentages reported in other countries. People should be more informed about RAS and the related preventive measures.

Abstract

Reptile-associated salmonellosis (RAS), Salmonella infection in humans, is acquired through contact with reptiles. Reptiles have become popular pet animals, and RAS is likely to be an underestimated but growing problem. No epidemiological data about RAS are routinely collected in Italy. In order to estimate the occurrence of RAS in the Italian human population and to investigate the exposure, two epidemiological studies on patients with sporadic salmonellosis were carried out in the Piedmont region, along with an evaluation of human exposure in public places displaying reptiles and with a survey on people awareness. RAS appeared make up 7% of sporadic salmonellosis in the first study and 3% in the second, more extensive study. A prevalence of 11.7% and 5.7%, respectively, were calculated for the age range of 0–21 years. It was observed that in public places displaying reptiles, it was possible to easily come into contact with the animals and their environment. Some knowledge about RAS emerged from the interviews with the general population, but preventive measures are not completely applied by reptile owners. In conclusion, RAS in Italy is present and constitutes a proportion of the human salmonellosis cases in line with the percentages reported in other countries. Exposure to reptiles should always be considered as a risk factor, and people should be more informed about RAS and the related preventive measures.

Zoonotic potential and prevalence of Salmonella serovars isolated from pets

Salmonellosis is a global health problem, affecting approximately 1.3 billion people annually. Most of these cases are related to food contamination. However, although the majority of Salmonella serovars are pathogenic to humans, animals can be asymptomatic carriers of these bacteria. Nowadays, a wide range of animals is present in human households as pets, including reptiles, amphibians, dogs, cats, ornamental birds, and rodents. Pets contaminate the environment of their owners by shedding the bacteria intermittently in their feaces. In consequence, theyare thought to cause salmonellosis through pet-to-human transmission. Each Salmonella serovar has a different zoonotic potential, which is strongly regulated by stress factors such as transportation, crowding, food deprivation, or temperature. In this review, we summarize the latest reports concerning Salmonella-prevalence and distribution in pets as well as the risk factors and means of prevention of human salmonellosis caused by contact with their pets. Our literature analysis (based on PubMed and Google Scholar databases) is limited to the distribution of Salmonella serovars found in commonly owned pet species. We collected the recent results of studies concerning testing for Salmonella spp. in biological samples, indicating their prevalence in pets, with regard to clinical cases of human salmonellosis.

Pet Reptiles: A Potential Source of Transmission of Multidrug-Resistant Salmonella

Salmonella spp. is widely considered one of the most important zoonotic pathogens worldwide. The close contact between reptiles and their owners provides favourable conditions for the transmission of zoonotic pathogen infections, and ~6% of human salmonellosis cases are acquired after direct or indirect contact with reptiles. Moreover, antimicrobial resistance is one of the most important health threats of the twenty-first century and has been reported in Salmonella strains isolated from pet reptiles, which could entail therapeutic consequences for their owners and breeders. The aim of this study was to assess Salmonella carriage by pet reptiles in pet shops and households, and their role in the transmission of antimicrobial resistance, to inform the owners about the possible risks factors. During the period between January 2019 and December 2019, 54 reptiles from pet shops and 69 reptiles from households were sampled in the Valencian Region (Eastern Spain). Three different sample types were collected from each reptile: oral cavity, skin, and cloacal swabs. Salmonella identification was based on ISO 6579-1:2017 (Annex D), serotyped in accordance with Kauffman-White-Le-Minor technique, and antibiotic susceptibility was assessed according to Decision 2013/652. The results of this study showed that 48% of the pet reptiles examined from households and pet shops carry Salmonella spp. All the strains isolated presented resistance to at least one antibiotic, and 72% were multidrug-resistant strains, the most frequently observed resistance patterns being gentamicin-colistin and gentamicin-colistin-ampicillin. The present study demonstrates that pet reptiles could be a source of human multidrug-resistant Salmonella infection. In this context, the most optimal prevention of multidrug-resistant Salmonella infections necessarily involves strict control of the sanitary status of reptile pet shops and hygienic handling by the individual owners at home.

Microbiological survey of sugar gliders (Petaurus breviceps) kept as pets in Italy

The sugar glider (Petaurus breviceps) is a small, arboreal, nocturnal, gliding mammalian possum belonging to the marsupial infraclass. Exotic marsupials, including sugar gliders, are becoming popular companion pets and, consequently, the risk of potential infections that can be transmitted to humans should be investigated. Data on the role of the sugar glider as a possible carrier of pathogenic and zoonotic bacteria are scarce and fragmentary. Therefore, this study is aimed at evaluating the prevalence of potentially zoonotic bacteria (Salmonella spp., Escherichia coli, Campylobacter spp., Pseudomonas spp., Klebsiella spp., Listeria monocytogenes and Yersinia enterocolitica) in 64 sugar gliders kept as pets in Italy. The highest prevalence of infection pertained to members of the family Enterobacteriaceae, in particular Citrobacter spp. (50%), Enterobacter spp. (28·1%) and Klebsiella pneumoniae (15·6%); Pseudomonas aeruginosa was isolated from 10 out of 64 samples (15·6%). All strains of Klebsiella pneumoniae exhibited some level of resistance to multiple antimicrobials (ampicillin, amoxicillin-clavulanic acid and doxycycline). SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study show that sugar gliders may act as carriers of potentially pathogenic agents for humans and other animal species, therefore caution should be exercised in the handling and contact with these animals.