Lactobacillus rhamnosus strains of oral and vaginal origin show strong antifungal activity in vitro

Figures & data

Table 1. List of Lactobacillus spp. and Candida spp. used in the study

Genus	Origin	Species
Lactobacillus	Oral cavity Vaginal	L. rhamnosus NEU427 L. rhamnosus ERB18, DSM 32,991 L. rhamnosus ERB 36, DSM 32,992 L. fermentum S1P2 L. fermentum S1P1 L. curvatus EB10 DSM 32,307 L. paracasei S1-P3 L. acidophilus EB03 L. crispatus 23B33 L. crispatus NEU458 DSM15224 L. gasseri EB01 L. jensenii 12B1 L. jensenii 22B42 L. rhamnosus PB01
Candida	Control CCUG strains Clinical isolates	C. albicans CCUG 46,390 C. dubliniensis CCUG 48,722 C. glabrata CCUG 63,819 C. krusei CCUG 56,126 C. parapsilosis CCUG 56,136 C. tropicalis CCUG 47,037 C. albicans CBS 562 NT C. dubliniensis 41_3 ZZMK C. glabrata CBS 863 C. krusei RV 491 C. parapsilosis 26 PBS C. tropicalis DSM 7524

Figure 1. Frequency distribution (%) of growth inhibition score 0–3 for each Lactobacillus spp. (all concentrations and all Candida spp.). Results are based on duplicate assays, repeated at three separate occasions

*L. rhamnosus ERB 36 DSM 32992 demonstrated the best growth inhibition properties against the Candida spp. displaying the highest number of score 0 and 1 (p < 0.001), followed by L. rhamnosus DSM 32991, L. jensenii DSM 32558, and L. rhamnosus PB01, respectively

Figure 2. Frequency distribution (%) of growth inhibition score 0–3 for each Candida spp. based on agar overlay interference tests with all 14 Lactobacillus spp. (all concentrations). Results are based on duplicate assays, repeated at three separate occasions

There was a statistically significant difference in growth susceptibility between the 12 Candida strains (p < 0.001). C. parapsilosis CCUG 56136 and C. parapsilosis clinical strain were growth inhibited to the highest extent displaying the highest number of score 0 and 1, while C. krusei CCUG 47037 and C. krusei clinical strain were only slightly inhibited or not inhibited displaying the highest number of score 2 and 3

Figure 3. Micro-sensor measurement of pH with selected Candida strains with L. rhamnosus DSM 32992 (10⁷ CFU/mL) in the bottom agar layer of the co-cultured agar overlay assay. Zero on the vertical axis represents the first measurement from the sensor of either a Candida colony or agar. No changes in pH values appeared for any of the strains at deeper levels in the agar