Antimicrobial Susceptibility of Staphylococcus aureus Isolated from Recreational Waters and Beach Sand in Eastern Cape Province of South Africa

Abstract

Background: Resistance of Staphylococcus aureus to commonly used antibiotics is linked to their ability to acquire and disseminate antimicrobial-resistant determinants in nature, and the marine environment may serve as a reservoir for antibiotic-resistant bacteria. This study determined the antibiotic sensitivity profile of S. aureus isolated from selected beach water and intertidal beach sand in the Eastern Cape Province of South Africa. Methods: Two hundred and forty-nine beach sand and water samples were obtained from 10 beaches from April 2015 to April 2016. Staphylococcus aureus was isolated from the samples using standard microbiological methods and subjected to susceptibility testing to 15 antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) was detected by susceptibility to oxacillin and growth on Brilliance MRSA II agar. Antibiotic resistance genes including mecA, femA rpoB, blaZ, ermB, ermA, ermC, vanA, vanB, tetK and tetM were screened. Results: Thirty isolates (12.3%) were positive for S. aureus by PCR with over 50% showing phenotypic resistance to methicillin. Resistance of S. aureus to antibiotics varied considerably with the highest resistance recorded to ampicillin and penicillin (96.7%), rifampicin and clindamycin (80%), oxacillin (73.3%) and erythromycin (70%). S. aureus revealed varying susceptibility to imipenem (96.7%), levofloxacin (86.7%), chloramphenicol (83.3%), cefoxitin (76.7%), ciprofloxacin (66.7%), gentamycin (63.3%), tetracycline and sulfamethoxazole-trimethoprim (56.7%), and vancomycin and doxycycline (50%). All 30 (100%) S. aureus isolates showed multiple antibiotic-resistant patterns (resistant to three or more antibiotics). The mecA, femA, rpoB, blaZ, ermB and tetM genes were detected in 5 (22.7%), 16 (53.3%), 11 (45.8%), 16 (55.2%), 15 (71.4%), and 8 (72.7%) isolates respectively; Conclusions: Results from this study indicate that beach water and sand from the Eastern Cape Province of South Africa may be potential reservoirs of antibiotic-resistant S. aureus which could be transmitted to exposed humans and animals.

Molecular epidemiology and mechanisms of antibiotic resistance inEnterococcusspp.,Staphylococcusspp., andStreptococcusspp. in Africa: a systematic review from a One Health perspective

“…Thirty MDR S. aureus isolates were recovered between April 2015 and April 2016 from 10 beaches in the Eastern Cape Province, South Africa (Table S2, online only). Notably, the isolates harbored mecA , femA , rpoB , blaZ , erm (B), and tet (M), making marine environments and public beaches potential depositaries of MDR S. aureus that can be transmitted to animals and humans. Further, the 50% resistance to VAN recorded is concerning to global health as it is a last‐resort antibiotic for treating MRSA infections.…”

“…Resistance genes from Enterococcus spp., Staphylococcus spp., and Streptococcus spp. have been detected in ground and surface water fed by effluents from hospitals and sewage processing plants, as well as runoff from animal farms that use antibiotics . Furthermore, genes that mediate resistance to last‐resort Gram‐positive bacteria–specific antibiotics, such as VAN, have been recovered from raw milk and other animal products, pigs, wild animals (buffalo, zebra, and cattle), waste water, effluents, and patients, which implicates both veterinary and agricultural (over)use of antibiotics as potential sources of antimicrobial resistance genes in humans …”

Challenge and Realities of Antimicrobial Resistance of Staphylococci at the University Hospital of Befelatanana Antananarivo

“…Other studies also confirm the high resistance of Staphylococcus aureus to this class of antibiotic (5,6) . This resistance is due to the production of a penicillinase by the strains (7) .…”

Molecular Epidemiology and Mechanisms of Antibiotic Resistance in Gram-positive Bacteria in Africa: A Systematic Review and Meta-Analysis from a One Health Perspective

“…Thirty MDR S. aureus were recovered between April 2015 to April 2016 from ten beaches in the Eastern Cape Province, South Africa (Table 2). Notably, the isolates harbored mecA, femA, rpoB, blaZ, erm (B) and tet (M) 11 , making marine environments and public beaches potential depositaries of MDR S. aureus that can be transmitted to animals and humans. Further, the 50% resistance to vancomycin recorded is concerning to global health due to its role as a last-resort antibiotic for treating MRSA infections.…”

“…High-level ABR has been reported in humans, animals and the environment, with indiscriminate antibiotic use being fingered as a major contributor in Africa. Resistance genes have been detected in surface water fed with runoff effluents from farms utilizing antibiotics, hospitals, and sewage processing plants as well as in ground water 9-11 . Furthermore, genes mediating resistance to last-resort GPB antibiotics such as vancomycin have been recovered from raw milk and animal products, pigs, wild animals (buffalo, zebra and cattle), waste water, effluents and patients, implicating veterinary and agricultural use of antibiotics as potential sources of resistance genes in humans 12-14 .…”