Our aim was to compare the composition and diversity of Lactobacillus microbiota in infants living in Malawi and south-western Finland.

The composition and diversity of the Lactobacillus group was analyzed in the feces of healthy six-month-old infants living in rural Malawi (n = 44) and south-western Finland (n = 31), using the quantitative polymerase chain reaction method (qPCR) and PCR-denaturing gradient gel electrophoresis fingerprinting (DGGE).

Malawian infants had higher counts of lactobacilli than their Finnish counterparts (7.45 log cells/g vs. 6.86 log cells/g, p < 0.001, respectively) and the Lactobacillus community was richer and more diverse in the Malawian infants. Leuconostoc citreum and Weissella confusa were the predominant species in both study groups, but Malawian infants were more often colonized by these species (100 % vs. 74.2 % p < 0.001; 95.5 % vs. 41.9 %, p < 0.001, respectively). Moreover, Lactobacillus ruminis, Lactobacillus gasseri, Lactobacillus acidophilus and Lactobacillus mucosae were detected more often in the Malawian infants (59.1 % vs. 0.0 %, p < 0.001; 38.6 % vs. 9.7 %, p = 0.004; 29.5 % vs. 0.0 %, p < 0.001; 22.7 % vs. 3.2 %, p = 0.017, respectively). However, Lactobacillus casei group species were only detected in the Finnish infants.

Malawian infants have a more abundant Lactobacillus microbiota with a distinct composition compared to Finnish infants. The environment, including diet and hygiene, may be among the factors influencing these differences.