Shiga toxin–producing Escherichia coli (STEC) O157:H7 is a well-recognized cause of bloody diarrhea and hemolytic-uremic syndrome (HUS). The ability of STEC strains to cause human disease is due to the production of Shiga toxins. The objectives of this study were to determinate the prevalence, serotypes, antibiotic susceptibility patterns and the genetic capability for Shiga toxin production in Escherichia coli (STEC) strains isolated from dairy cattle farms in two rural communities in the Eastern Cape Province of South Africa. Fecal samples were collected between March and May 2014, from individual cattle (n = 400) in two commercial dairy farms having 800 and 120 cattle each. Three hundred presumptive isolates obtained were subjected to polymerase chain reactions (PCR) for identification of O157 serogroup and Shiga toxin producing genes (stx1, stx2) on genomic DNA extracted by boiling method. Susceptibility of the isolates to 17 antibiotics was carried out in vitro by the standardized agar disc-diffusion method. Based on direct PCR detection, 95 (31.7 %) isolates were identified as O157 serogroup. The genetic repertoire for Shiga toxin production was present in 84 (88.42 %) isolates distributed as stx1 (37), stx2 (38) and stx1/2 (9) respectively while 11 of the isolates did not harbor Shiga toxin producing genes. Multiple antibiotic resistances were observed among the isolates and genetic profiling of resistance genes identified bla ampC 90 %, bla CMY 70 %, bla CTX-M 65 %, bla TEM 27 % and tetA 70 % and strA 80 % genes among the antimicrobial resistance determinants examined. We conclude that dairy cattle farms in the Eastern Cape Province are potential reservoirs of antibiotic resistance determinants in the province.
Background: Antimicrobial resistance in microorganisms are on the increase worldwide and are responsible for substantial cases of therapeutic failures. Resistance of species of Enterococcus to antibiotics is linked to their ability to acquire and disseminate antimicrobial resistance determinants in nature, and wastewater treatment plants (WWTPs) are considered to be one of the main reservoirs of such antibiotic resistant bacteria. We therefore determined the antimicrobial resistance and virulence profiles of some common Enterococcus spp that are known to be associated with human infections that were recovered from hospital wastewater and final effluent of the receiving wastewater treatment plant in Alice, Eastern Cape. Methods: Wastewater samples were simultaneously collected from two sites (Victoria hospital and final effluents of a municipal WWTP) in Alice at about one to two weeks interval during the months of July and August 2014. Samples were screened for the isolation of enterococci using standard microbiological methods. The isolates were profiled molecularly after targeted generic identification and speciation for the presence of virulence and antibiotic resistance genes. Results: Out of 66 presumptive isolates, 62 were confirmed to belong to the Enterococcus genusof which 30 were identified to be E. faecalis and 15 E. durans. The remaining isolates were not identified by the primers used in the screening procedure. Out of the six virulence genes that were targeted only three of them; ace,efaA, and gelE were detected. There was a very high phenotypic multiple resistance among the isolates and these were confirmed by genetic analyses. Conclusions: Analyses of the results obtained indicated that hospital wastewater may be one of the sources of antibiotic resistant bacteria to the receiving WWTP. Also, findings revealed that the final effluent discharged into the environment was contaminated with multi-resistant enterococci species thus posing a health hazard to the receiving aquatic environment as these could eventually be transmitted to humans and animals that are exposed to it.
Enterococci have emerged as an important opportunistic pathogen causing life-threatening infections in hospitals. The emergence of this pathogen is associated with a remarkable capacity to accumulate resistance to antimicrobials and multidrug-resistance particularly to vancomycin, erythromycin and streptomycin have become a major cause of concern for the infectious diseases community. In this paper, we report the prevalence of Enterococcus in respect to species distribution, their virulence and antibiogram profiles. Four hundred fecal samples were collected from two piggery farms in the Eastern Cape Province of South Africa. Enterococcus species were isolated and confirmed with generic specific primers targeting the tuf gene (encoding elongation factor). The confirmed isolates were speciated with enterococci species specific primers that aimed at delineating them into six species that are commonly associated with infections in humans. Antibiotic susceptibility testing was performed by disc diffusion method. Six virulence genes and antimicrobial resistance profiles of the isolates were evaluated molecularly. Molecular identification of the presumptive isolates confirmed 320 isolates as Enterococcus spp. Attempt at speciation of the isolates with primers specific for E. faecalis, E. durans, E. casseliflavus, E. hirae and E. faecium delineated them as follows: E. faecalis (12.5 %), E. hirae (31.25 %), E. durans (18.75 %) and E. faecium (37.5 %) while E. casseliflavus was not detected. All the isolates were resistant to vancomycin, streptomycin and cloxacillin, and to at least two different classes of antibiotics, with 300 (93.8 %) isolates being resistant to five or more antibiotics. Also, three out of the six virulence genes were detected in majority of the isolates and they are Adhesion of collagen in E. faecalis (ace) (96.88 %), gelatinase (gelE) (93.13 %) and surface protein (esp) (67.8 %). There was high prevalence of multi-resistant vancomycin Enterococcus spp. (VREs) in the fecal samples of pigs in the farms studied, and this poses health implications as vancomycin is an important drug in human medicine. Further studies are needed to determine the spread of vancomycin resistance among bacteria of human origin in the communities.
The genus Enterococcus is known to possess the capacity to acquire and disseminate antimicrobial resistant determinants alongside the ability to produce various virulence genes that enables it to establish infections. We assessed the prevalence and antibiogram profiles of Enterococcus spp. in faecal samples of dairy cattle. Faecal swab samples were collected from 400 dairy cattle from two commercial cattle farms in two rural communities in the Eastern Cape, South Africa. Confirmation of enterococci isolates was carried out by PCR targeting of the tuf gene. Species delineation was by species-specific primers targeting the superoxide dismutase (sod A) gene in a multiplex PCR assay. Isolates were screened for the presence of the following virulence genes (ace, gel E, esp, efa A, cyl A and hyl E) and antimicrobial resistance determinants to erythromycin, vancomycin and streptomycin were evaluated molecularly. A total of 340 isolates were confirmed as belonging to the genus Enterococcus . Species distribution among the isolates consisted of Enterococcus faecium (52.94 %) and Enterococcus durans (23.53 %) in preponderance compared to the three other species, namely Enterococcus faecalis (8.8 %), Enterococcus hirae (8.6 %) and Enterococcus casseliflavus (5.9 %). All were resistant to vancomycin, while 99 % showed resistance to aminoglycoside and 94 % to macrolide. Three virulence genes (ace, gel E and esp) were detected in almost all the confirmed isolates. The resistance determinants van B (19.7 %), van C1 (25 %), van C2/3 (26.3 %) erm B (40.29 %) and str A (50.88 %) were detected among the isolates. A high prevalence of multidrug-resistant enterococci isolates was detected in this study and the genetic repertoire to survive in the presence of antimicrobial agents was present in these organisms.
Streptococcus agalactiae or Group B Streptococcus (GBS) is the leading cause of neonatal morbidity and mortality resulting in septicaemia, bacteraemia and meningitis. Long term problems in children range from loss of hearing to mental retardation. While Intrapartum Antibiotic Prophylaxis (IAP) has reduced the incidence of S. agalactiae infection, it still remains the leading cause of disease in neonates. GBS has ten capsular types whose distribution varies across the world. Therefore, this study sought to determine the prevalence of GBS in Namibia and South Africa amongst pregnant women between 35 and 37 weeks gestation and elucidate the capsular types. Lower vaginal and rectal swabs were collected from pregnant women between 35 and 37 weeks gestation. Five hundred and thirty pregnant women were recruited into the study in Windhoek, Namibia while one hundred pregnant women were recruited in the Eastern Cape, South Africa. The swabs were cultured on 5% sheep blood agar (Biomerieux, New Jersey, USA) for isolation of GBS. Presumptive isolates were confirmed using both the Vitek (2) and molecular techniques targeting the scpB gene. Capsular typing was performed in a multiplex PCR with capsular specific primer pairs. The prevalence of GBS in Namibia was 13.6 and 37% in South Africa respectively. In both countries most women were dually colonised with GBS. Capsular types II, III and V were the most prevalent. The prevalence of GBS in Namibia was lower than in South Africa in this study. The prevalence in both countries was not different from those reported in other African countries and around the world. The predominant capsular types in this study are the ones commonly associated with adverse maternal outcomes.
30 January 2019 in BMC Complementary and Alternative Medicine
Streptococcus agalactiae also known as Group B Streptococcus (GBS) is a major cause of disease in pregnant women and new born babies where it causes early and late onset disease characterised by sepsis, pneumonia and meningitis. Ten to 37 % of pregnant women in the world are colonised with GBS while intrapartum antibiotic prophylaxis has led to significant reduction in early onset disease. The increase in drug resistant microorganisms has become a major threat. Development of vaccines is still in progress so there is need for new and safer alternatives to treatment. Benzyl penicillin, Ampicillin, Cefotaxime, Ceftriaxone, Levofloxacin, Erythromycin, Clindamycin, Linezolid, Vancomycin, Tetracycline and Cotrimoxazole, Olea europaea leaf extracts and essential oil were tested against GBS isolates from South Africa and Namibia. The isolates showed 100% sensitivity to benzyl penicillin, ampicillin, ceftriaxone, levofloxacin, linezolid, vancomycin, O. europaea leaf extracts and essential oils. Only one isolate (0.6%) was resistant to cefotaxime and 23.4 and 10.4% were resistant to clindamycin and erythromycin respectively. GBS isolates showed sensitivity to O. europaea extracts at low minimum inhibitory concentrations. Β lactams are still the drugs of choice for treatment of GBS disease but O. europaea extracts potent as an alternative source of antimicrobials.