Background: Salmonellae are important food and waterborne pathogens and the leading causes of the most widespread acute
gastrointestinal illnesses around the globe. The organism has been detected in a wide range of host species such as mites,
insects, crustaceans, mussels, fish, amphibians, reptiles, birds and mammals including wildlife animals. Salmonellae have been
isolated in many species of bats in other countries. In the Philippines, there are 70 species of Philippine bats reported of which
nine are considered as endemic. Although human salmonellosis (typhoid, paratyphoid and other Salmonella-associated infections)
was the primary cause of illnesses and death from the 60 reported foodborne outbreaks (1995 to 2004), no case was ever reported
involving Philippine bats. Since transmission of Salmonella from wildlife to humans is possible, as advocated by previous
reports, the present study endeavored to isolate and molecularly detect Salmonella spp. from Philippine bats captured from
Aklan, Laguna and Quezon City using conventional isolation method and polymerase chain reaction assay respectively.
Materials, Methods & Results: A total of 96 apparently healthy bats were used in the study. Bats were captured using nylon
mobile mist nets of 3 m long and 1.5 m high with 35 mm mesh size. Eleven species of bats were collected and identified following
the reported key to the identification of Philippine bats. Majority of the collected species were insectivores under family
Vespertilionidae while the largest population of the Philippine bats were frugivores belonging to family Pteropodidae. Necropsy
was performed and intestines were collected and subjected to conventional culture method and PCR detection for Salmonella
spp. Two samples (2.08%) were molecularly detected as positive for Salmonella spp. bacterial pathogen. The positive samples
were obtained from the intestines of the adult female insectivorous bat species, Miniopterus australis and M. schreibersi,
originating from Pangihan cave of Barangay Pablacion, Malay in Aklan. No Salmonella spp. was isolated using the conventional
method.
Discussion: The study reports the first detection and molecular evidence of Salmonella spp. in Philippine bats by PCR using
intestinal samples. In addition, the data strongly indicated that PCR detection appears to be more sensitive over the conventional
isolation method. The successful detection was attributed to the ability of PCR to sensitively detect atypical Salmonella and
non-viable Salmonella cells. Results in the present study revealed that the Philippine bats, Miniopterus australis and M.
schreibersi, both adult female insect-eating bats captured in Pangihan cave of Barangay Pablacion, Malay, Aklan harbored
Salmonella in their intestines. Since salmonellae have been detected in a large variety of environment and host species including
insects, these bats may have acquired these microorganisms in water and in their diet. This finding shows that Philippine bats
may serve as potential reservoir and carrier of Salmonella organisms. The data also strongly indicates that bats may actively
contribute in the dissemination of salmonellae into the environment through fecal route. This currently makes Philippine bats as
a potential threat to livestock and may pose a serious public health concern, since all serotypes of Salmonella are considered to
be pathogenic to humans.
