Use of portable enrichment unit in rapid characterization of infantile intestinal enterobacterial microbiota

Figures & data

Figure 1. A portable microbe enrichment unit (PMEU; Finnoflag Oy and Samplion Oy, Kuopio and Siilinjärvi, Finland) (19).

Table I. Enterobacterial isolates from fecal samples taken at the ages of 3 and 12 months from infants I–VIII.

Enterobacterial species	I	II	III	IV	V	VI	VII	VIII	Total
3 months
Citrobacter amalonaticus	0	0	0	0	0	0	0	0	0
Citrobacter freundii	1	0	0	0	0	0	0	0	1
Enterobacter cloacae	2	0	0	0	0	0	0	1	3
Escherichia coli	1	0	1	0	0	0	2	0	4
Escherichia hermannii	0	0	0	0	0	1	0	0	1
Klebsiella axytoca	0	0	2	3	0	1	0	0	6
Klebsiella pneumoniae	0	0	0	0	0	1	0	0	1
Kluyvera ascorbata	1	0	0	0	0	0	0	0	1
Kluyvera cryocrescens	0	0	0	0	2	0	0	0	2
Pantoea agglomerans	1	0	0	0	0	0	0	0	1
Unrecognized	0	0	0	0	0	1	0	0	1
Total	6	0	3	3	2	4	2	1	21
12 months
Citrobacter amalonaticus	1	0	0	0	2	0	0	0	3
Citrobacter freundii	0	3	0	0	1	0	0	0	4
Enterobacter cloacae	1	0	0	0	1	0	0	0	2
Escherichia coli	2	3	1	5	4	7	0	3	25
Escherichia hermannii	0	0	0	0	0	0	0	0	0
Klebsiella axytoca	1	0	2	0	0	0	0	1	4
Klebsiella pneumoniae	0	2	0	0	1	2	0	0	5
Kluyvera ascorbata	2	0	0	0	0	0	0	0	2
Kluyvera cryocrescens	0	0	0	0	0	0	0	0	0
Pantoea agglomerans	0	0	0	0	0	0	0	0	0
Unrecognized	1	0	0	0	0	0	0	0	1
Total	8	8	3	5	9	9	0	4	46
All isolates	14	8	6	8	11	13	2	5	67

Table II. Enterobacterial isolates detected by direct plating and enrichment in the PMEU in samples from infants I–VIII.

Method used for isolation	I	II	III	IV	V	VI	VII	VIII	Total
3 months
Direct plating alone	2	0	1	0	1	0	1	0	5
Both direct plating and enrichment	3	0	1	1	1	1	1	1	9
Only after enrichment	1	0	1	2	0	3	0	0	7
Total	6	0	3	3	2	4	2	1	21
12 months
Direct plating alone	2	1	1	1	0	5	0	0	10
Both direct plating and enrichment	3	3	1	1	0	0	0	4	12
Only after enrichment	3	4	1	3	9	4	0	0	24
Total	8	8	3	5	9	9	0	4	46
All isolates	14	8	6	8	11	13	2	5	67

The proportion of isolates detected only by enrichment in the PMEU was 33.3% at the age of 3 months and 53.3% at the age of 12 months. See also Table I and Figure 2a and b.

Figure 2. Cumulative presentation of enterobacterial isolates by species detected only by direct plating (DP), both by direct plating and enrichment (ENR; 8 h, +37°C, MacConkey broth in the PMEU), and only after enrichment at the age of (a) 3 months and (b) 12 months. Note that, at the age of 12 months, on average more Escherichia coli strains were isolated by combination of direct plating and enrichment than by direct plating alone (p = 0.03).

Figure 3. Dendrograms showing phenotypic homologies of the enterobacterial isolates from infants I (a) and III (b) studied by the PhenePlateTM technique (Bactus AB, Huddinge, Sweden) [21,22]. The figures were processed by PhPWIN software (PhPlate AB, Stockholm, Sweden). Isolates were regarded as the same strain when the similarity level was 97.5% or more (marked by a vertical dotted line). (1) Kluyvera ascorbata strain that was isolated from samples taken at the ages of both 3 and 12 months from infant I. (2) Escherichia coli strain that was isolated from samples taken at the ages of both 3 and 12 months from infant III.

Hakalehto E. Menetelmä ja laite mikrobiologisten näytteiden rikastamista ja tutkimista varten. [Method for detecting microbes from an enrichment culture.] Finnish Patent No. 106561. 2001.

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