Molecular characterization of clonal lineage and staphylococcal toxin genes fromS. aureusin Southern Nigeria

Abstract

BackgroundStaphylococcus aureus is a human colonizer with high potential for virulence, and the spread of the virulent strains from the colonized hosts to non-carriers in the community is on the increase. However, there are few reports on comprehensive analysis of staphylococcal enterotoxin (SE) genes with clonal lineage in S. aureus in Africa. This is essential because of diversity of cultures and habits of the people. This study analyzed spa types and enterotoxin genes in S. aureus strains previously isolated from the human nostrils, poultry and clinical samples in Southern Nigeria.MethodsForty-seven S. aureus isolates were obtained from humans nostrils (n = 13), clinical strains (n = 21) and poultry (n = 13) from previous studies in Southern Nigeria. The strains were analyzed for mecA gene, selected toxins genes (sea, seb, sec, sed, see, seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq, ser, seu) and Panton-Valentine leukocidin (PVL) gene (lukS-PV/lukF-PV) by PCR. Population structures of the strains were detected by Staphylococcal protein A (spa) typing.ResultsTwenty different spa types were obtained with the highest percentages, 17% observed in spa type t091 from clinical, nasal and poultry samples while t069 was the most prevalent spa type in poultry. Two MRSA were only detected in human strains. The poultry strains had the highest occurrence of SE genes (18%) followed by nasal strains (15%) and clinical strains (10%). Eighty-nine percent of all tested isolates harbored at least one SE gene; seo was the most prevalent (34%) followed by seg (30%) and sea (21%), while sec, see and sej were absent in all strains. Spa type t355 was associated with lukS-PV/lukF-PV gene and complete absence of all studied SE. Sea, seq, seb, sek were associated with spa type t069; sea was associated with t127 while sep was associated with spa type t091. There were coexistences of seo/seg and sei/seg.ConclusionsThe higher carriage of staphylococci enterotoxin genes by the nasal and poultry S. aureus strains suggests a high potential of spread of staphylococcal food poisoning through poultry and healthy carriers in the community. This is the first report of high occurrence of staphylococcal enterotoxins genes in poultry from Nigeria.

Molecular characterization and virulence gene profiling of methicillin-resistant Staphylococcus aureus associated with bloodstream infections in southern China

“…There was the same proportion between sei and seg in our study. Previous studies have indicated associations between seg and sei , in which the most frequent SE genes detected in different locations were seg/sei , as reported in other countries ( Loncarevic et al, 2005 ; Kolawole et al, 2013 ; Ayeni et al, 2018 ). seg and sei were frequently encountered together because they were within the same cluster in a 3.2-kb DNA fragment ( Asiimwe et al, 2017 ).…”

Profiling virulence genes in Palestinian strains of community- acquired methicillin-resistant Staphylococcus aureus, exposing those encoding exfoliative toxin

“…Here, all the strains examined possessed at least one staphylococcal enterotoxin gene with seo being the most prevalent gene. This agreed with the results of [20] obtained in Algeria. This is a high occurrence with public health implications as staphylococcal enterotoxins can induce T-cell stimulation, resulting in systemic illness such as toxic shock syndrome and food poisoning.…”

Clonal diversity and spatial dissemination of multi-antibiotics resistant Staphylococcus aureus pathotypes in Southwest Nigeria

“…Functional agr groups were reported to enhance persistent staphylococci bacteraemia and soft tissue tropism with low antibiotic susceptibility to penicillin, cephalosporin and vancomycin [ 7 , 8 ]. Similar clonal spread of MRSA (methicillin-resistant Staphylococcus aureus ) and MSSA (methicillin-susceptible Staphylococcus aureus ) is becoming pandemic in several communities in Africa, mostly Nigeria where animal husbandry, behavioural responses and declined demographic factors enhance continuous dissemination of staphylococcal infection with high degree of antibiotic resistance [ 9 ]. The misuse and unregulated prescription of penicillin derivatives in high and uncontrollable proportion for treating several extra-intestinal infections such as abscess, ear infections, subcutaneous tissue inflammation, nasal discharges particularly in children and post-surgical wound culminated in a high rate of resistance and continuous development of methicillin-resistance strains [ 10 , 11 ].…”