A bacteriocin produced by certain M-type 49Streptococcus pyogenesstrains when incubated anaerobically

Abstract

SummaryBacteriocin production (P)-typing of 75 M-type 49 group-A streptococci obtained from a variety of epidemiological incidents in different countries gave no evidence of production under the usual aerobic test conditions. However, with anaerobic incubation, 28% of the strains gave a pattern of inhibitory activity against the indicator strains which was indistinguishable from that previously attributed to the bacteriocin, streptococcin A-FF22 (SA-FF22). Isolation and partial purification of the M type 49 bacteriocin (SA-M49) by freeze–thaw elution from anaerobically grown lawn cultures, followed by ammonium sulphate precipitation and Sephadex chromatography, showed the activity to be associated with a heat-stable proteinaceous molecule of molecular weight approximately 8000 – properties similar to those of SA-FF22. SA-FF22 and SA-M49 were found to have identical inhibitory spectra including immunity of the producer strains to the inhibitory activity of both the homologous and heterologous bacteriocin preparations. SA-M49 production occurred in some strains of phage subtypes II, III and provisional VI and. since it was a consistent property for all isolates from single outbreaks of infection, it provides a means of discriminating between strains of each of these three phage subtypes. There was no evidence of any increased incidence of SA-M49 production in M-type 49 strains associated with nephritic sequelae

Duplication of the lantibiotic structural gene in M-type 49 group A streptococcus strains producing streptococcin A-M49

“…Of the 21 strains tested, 7 strains (33%) produced an inhibitory activity, after anaerobic incubation, indistinguishable from that of strain FF22. In accordance with the results of a previous survey (15), none of the M-type 49 strains tested in the current study produced an ScnA-like inhibitory pattern following aerobic incubation. Strains were also examined by the PCR technique with crude cell lysates as previously described (4).…”

“…Tagg and Skjold (15) previously reported that 28% (21 of 75) of Streptococcus pyogenes strains of M-type 49 tested produced an inhibitory activity indistinguishable from that attributed to ScnA. These strains were from different phage subtypes and were isolated from various geographical regions.…”

“…Twenty-one M-type 49 group A streptococcal strains obtained from different geographical locations and isolated from patients with a variety of diseases (some strains were tested previously) were screened by the deferred antagonism method for production of streptococcin A-M49 (15). Of the 21 strains tested, 7 strains (33%) produced an inhibitory activity, after anaerobic incubation, indistinguishable from that of strain FF22.…”

“…Total cellular DNA from strain FF22 (scnA-containing strain [5]), strain GT8760 (an M-type 49 strain which does not produce inhibitory activity [15]), and strains GT9538 and GT9653 (which produce streptococcin A-M49 inhibitory activity [15]) was prepared as previously described (3). The DNA was digested and used in Southern blot analysis with the 2.8-kb fragment containing the senA gene (5) as a probe.…”

Variable Characteristics of Bacteriocin-Producing Streptococcus salivarius Strains Isolated from Malaysian Subjects

“…The production experiment was repeated without adjusting the pH of the medium after fermentation (without adsorption) to calculate levels of lantibiotics attached to the producer cells. However, attempts to recover lantibiotics from the cell-free supernatant of this preparation using 80% ammonium sulphate saturation as described previously [41] showed that 60–70% of lantibiotic produced by NU10, YU10 and K12 strains presented in this study is cell-wall associated peptide ( Table 7 ). The bacteriocin units (arbitrary units) were calculated as mentioned previously [38] .…”