Factors affecting production of coccoid forms by Campylobacter jejuni on solid media during incubation

Abstract

Conditions influencing the conversion of oxygen into toxic derivatives in media were investigated for their effects on production of coccoid forms in cultures of the enteric pathogen Campylobacter jejuni. Compared with stored media, production of coccoid forms was less on freshly prepared media. Whether freshly prepared or stored before use, brucella agar media produced the fewest coccoid forms under the test conditions. Addition of supplements used as detoxifying agents minimized production of these forms on media but antibiotic formulations used in selective media did not influence production of coccoid forms. Furthermore, the type of incubation atmosphere and the strain of C. jejuni influenced the proportions of coccoid forms in cultures. It was deduced from electron microscopy observations during prolonged incubation of cultures that the process of conversion to coccoid forms involves a loss of spiral morphology, a shortening of the cell and retraction of the cytoplasm towards a cell terminal region. Coccoid forms and some intermediate forms in thin sections were found to lack cell integrity. It is concluded that coccoid form production in cultures is a degenerate response to toxic oxygen derivatives in cultures.

Influence of activated charcoal, porcine gastric mucin and β-cyclodextrin on the morphology and growth of intestinal and gastric Helicobacter spp.

“…Furthermore, culture media supplemented with activated charcoal or β-cyclodextrin delayed the conversion to coccoid forms by all the helicobacters we examined. In general, a spiral to coccoid conversion was more rapid in broth than on solid media, most likely due to the dissolved toxic substances enhancing the coccoid transformation (Moran & Upton, 1987b ;Coudron & Statton, 1995). The ability to delay the spiral to coccoid conversion may be beneficial in the production of cell surface antigens for immunodiagnostic tests since such conversion has been shown to induce changes in the cell wall composition of H. pylori and other bacteria (Costa et al, 1999 ;Signoretto et al, 2000).…”

Comparison of Methods Used to Separate the Inner and Outer Membranes of Cell Envelopes of Campylobacter spp.

“…Therefore, this material was cell envelope fragments rather than true OM fragments. This material possibly originated from the degenerate coccoid cells which are osmotically fragile (Moran & Upton, 1986) …”

Influência da vida séssil e planctônica no perfil de resistência antimicrobiana de Campylobacter jejuni isoladas de carcaças de frangos comercializadas no Brasil

“…Porém, Rollins e Colwell (1986), Moran e Upton (1987) e EMBRAPA (2012) descreveram que em condições desfavoráveis ou adversas, estes micro-organismos, tradicionalmente na forma espiralada, adquirem a forma esférica ou cocóide, contudo, sem perder o poder infectante.…”

“…Campylobacter possuem um flagelo monopolar ou bipolar, que aliados ao formato em espiral conferem ao micro-organismo movimento rápido e característico em forma de saca-rolha (MORAN e UPTON, 1987;BRASIL, 2011;GALATE e BANGDE, 2013).…”

“…Entre eles, a degeneração do formato espiral para a forma cocóide e a associação em biofilmes (ROLLINS e COLWELL, 1986;MORAN e UPTON, 1987;BUSEWLL et al,1998;EMPRABA, 2012;ICA et al, 2012;NGUYEN et al, 2012). Uma forma de C. jejuni superar sua fragilidade diante da adversidade ambiental é a sua capacidade de se aderir a superfícies e formar biofilme (ICA et al, 2012;NGUYEN et al, 2012).…”