Staphylococcus aureus Complex in the Straw-Colored Fruit Bat (Eidolon helvum) in Nigeria

Abstract

Bats are economically important animals and serve as food sources in some African regions. They can be colonized with the Staphylococcus aureus complex, which includes Staphylococcus schweitzeri and Staphylococcus argenteus. Fecal carriage of S. aureus complex in the straw-colored fruit bat (Eidolon helvum) has been described. However, data on their transmission and adaptation in animals and humans are limited. The aim of this study was to investigate the population structure of the S. aureus complex in E. helvum and to assess the geographical spread of S. aureus complex among other animals and humans. Fecal samples were collected from E. helvum in Obafemi Awolowo University, Ile-Ife, Nigeria. The isolates were characterized by antimicrobial susceptibility testing, spa typing and multilocus sequence typing (MLST). Isolates were screened for the presence of lukS/lukF-PV and the immune evasion cluster (scn, sak, chp) which is frequently found in isolates adapted to the human host. A Neighbor-Joining tree was constructed using the concatenated sequences of the seven MLST genes. A total of 250 fecal samples were collected and 53 isolates were included in the final analysis. They were identified as S. aureus (n = 28), S. schweitzeri (n = 11) and S. argenteus (n = 14). Only one S. aureus was resistant to penicillin and another isolate was intermediately susceptible to tetracycline. The scn, sak, and chp gene were not detected. Species-specific MLST clonal complexes (CC) were detected for S. aureus (CC1725), S. argenteus (CC3960, CC3961), and S. schweitzeri (CC2463). STs of S. schweitzeri from this study were similar to STs from bats in Nigeria (ST2464) and Gabon (ST1700) or from monkey in Côte d'Ivoire (ST2058, ST2072). This suggests host adaptation of certain clones to wildlife mammals with a wide geographical spread in Africa. In conclusion, there is evidence of fecal carriage of members of S. aureus complex in E. helvum. S. schweitzeri from bats in Nigeria are closely related to those from bats and monkeys in West and Central Africa suggesting a cross-species transmission and wide geographical distribution. The low antimicrobial resistance rates and the absence of the immune evasion cluster suggests a limited exposure of these isolates to humans.

Antimicrobial resistant and enteropathogenic bacteria in ‘filth flies’: a cross-sectional study from Nigeria

“…However, the low antimicrobial resistance rates, the absence of lukF -PV/ lukS -PV and sak might also suggest that S. aureus from flies are rather of animal (e.g. livestock or wildlife) than of human origin 16 – 18 . However, other factors not investigated in our study (e.g.…”

Clinical Staphylococcus argenteus Develops to Small Colony Variants to Promote Persistent Infection

“…Staphylococcus argenteus is a novel staphylococcal species closely related to Staphylococcus aureus , and is considered as a part of S. aureus complex (also including Staphylococcus schweitzeri ) ( Holt et al, 2011 ; Tong et al, 2015b ; Moradigaravand et al, 2017 ; Olatimehin et al, 2018 ). It was first reported in northern Australia as a special S. aureus clone complex (CC) (grouped as CC75), which is highly divergent at the multiple locus sequence typing (MLST) loci compared to S. aureus , and therefore difficult to classify ( Okuma et al, 2002 ; McDonald et al, 2006 ; Ng et al, 2009 ).…”

“…By now, S . argenteus has been reported worldwide, but studies are still too few to reflect its clear distribution or clinical features ( McDonald et al, 2006 ; Jenney et al, 2014 ; Monecke et al, 2014 ; Dupieux et al, 2015 ; Thaipadungpanit et al, 2015 ; Tong et al, 2015b ; Argudin et al, 2016 ; Chantratita et al, 2016 ; Zhang et al, 2016 ; Olatimehin et al, 2018 ).…”

Which methods are appropriate for the detection of <em>Staphylococcus argenteus</em> and is it worthwhile to distinguish <em>S. argenteus</em> from <em>S. aureus</em>?

“…Less is also known about the S. argenteus transmission ways, but several hosts and sources of isolation have been described. According to the metadata belonging to the deposited sequences in the NCBI database, 22 the majority of S. argenteus isolates have been isolated from humans but also from various animals, such as gorilla and bats, 29 , 30 and from environmental samples of unknown origin. Although globally distributed, most of the S. argenteus isolates originate from Asia.…”