Dysmotility and Proton Pump Inhibitor Use Are Independent Risk Factors for Small Intestinal Bacterial and/or Fungal Overgrowth

C. Jacobs; E. Coss Adame; A. Attaluri; J. Valestin; S. S. C. Rao

Disclosures

Aliment Pharmacol Ther. 2013;37(11):1103-1111. 

In This Article

Results

Demographics and Symptom Profiles

One hundred and sixty eight subjects (M/F = 54/114; ages 17–82 years; average age 44) were evaluated. Eighteen subjects were excluded; six because of incomplete motility studies or patient compliance with manometry protocol; six other subjects who had motility studies but either failed to provide information on PPI use or we could not clearly ascertain its use from their medical records; and six other subjects because of incomplete culture data or suspected contamination. Thus, 150 subjects (M/F = 46/104; ages 17–82 years; average age 43) were examined.

The mean (95% CI) duration of symptoms was not statistically different (P > 0.05) between the groups (SIBO = 58, 32–83 months; SIFO 47, 27–66; Mixed = 56, 30–83; Negative = 53, 35–71). Comorbid conditions in the study population included diabetes (13 subjects) (SIBO 6, Mixed 1, Negative 4 and SIFO 2) and scleroderma (five subjects) (SIBO 1, Mixed 1, Negative 2 and SIFO 1). BMI was not different among the groups (mean BMI in SIBO = 31; Mixed = 30, Negative = 31 and SIFO = 29 respectively).

Results for the mean baseline symptom scores are shown in Figures 1,2 and in Table 1. The overall mean baseline total symptom scores were similar between those with SIBO and/or SIFO and those with a negative culture (44 vs. 42) (Figure 1). Subjects with SIBO and/or SIFO had higher symptom severity scores for chest pain, belching, bloating, indigestion, nausea, diarrhoea and gas, but lower scores for abdominal pain, fullness and vomiting (Table 1). The baseline mean total symptom scores for each of the four groups are as follows: SIBO = 43; Mixed SIBO/SIFO = 42; SIFO = 48; and No overgrowth = 42, P > 0.05. The mean scores for each symptom and for each group are shown in Figure 1. There was no difference in the prevalence of symptoms between those who had a positive culture for bacterial overgrowth or fungal overgrowth vs. those who had a negative culture, except for chest pain (P < 0.05), probably inconsequential.

Figure 1.

The distribution of the mean symptom severity score for each symptom among the four groups of subjects.

Figure 2.

Prevalence of overgrowth in the study population (left) and the distribution of patients with SIBO or SIFO or SIBO/SIFO.

Prevalence of SIBO/SIFO

Based on a growth of bacterial concentration of ≥103 CFU/mL, we found that 94/150 (62.7%) patients were positive for overgrowth: 38/94 (40%) had SIBO, 24/94 (26%) had SIFO and 32/94 (34%) had mixed SIBO/SIFO (Figure 2). Based on a growth of bacterial concentration ≥105 CFU/mL, 77/150 (51%) had overgrowth: 20/77 (26%) had SIBO, 40/77 (52%) SIFO and 17/77 (20%) had mixed SIBO/SIFO (Table 2).

When we compared the two bacterial concentrations (>103 vs. >105), we found significant difference in the prevalences of positive cultures for SIBO, 70/150 (103 CFU/mL) vs. 37/150 (105 CFU/mL) based on the presence of a positive culture (P = 0.0001) as well as for the SIBO group alone, 38/94(103 CFU/mL vs. 20/77 (105 CFU/mL); P = 0.007) and Mixed SIBO/SIFO group (32/94 (103 CFU/mL) vs. 17/73 (105 CFU/mL); P = 0.01). (Table 2)

The predominant aerobic bacterial organisms that were cultured included: alpha haemolytic Streptococcus species (n = 32); nonhaemolytic Streptococcus including Enterococcus and Stomatococcus species (n = 10); Klebsiella species (n = 8); E. coli (n = 6); Neisseria sp (n = 5); Staphlococcus sp (n = 4); and Enterobacter sp (n = 3). Eight patients had positive anaerobic cultures including Veillonella sp (n = 5); Clostridium species (n = 1); Bacteroides (n = 1); and Peptostreptococcus (n = 1). Fungal growth was predominately due to Candida species (albicans or torulopsis).

The Effects of Dysmotility on Overgrowth

>103 Analysis. Eighty of 150 (53%) patients with chronic GI complaints had dysmotility. Sixty-one of 80 (76%) patients with dysmotility had small bowel bacterial and/or fungal overgrowth based on bacterial growth of >103 CFU/ml. (Figure 3 and Table 2). A significant relationship (P = 0.0003) was found between dysmotility and small bowel bacterial overgrowth, even when controlling for PPI use. Patients with dysmotility had an odds ratio of 3.60 of having a small bowel bacterial overgrowth than those with normal motility.

Figure 3.

The prevalence of SIBO and/or SIFO in patients with dysmotility and in PPI users.

Dysmotility was an independent and significant predictor (P = 0.0003) for small bowel bacterial overgrowth (SIBO and/or SIFO) (Figure 3, Table 2). Analyses done on each separate group (SIBO, SIFO and Mixed SIBO/SIFO vs. negative for dysmotility) were found to be significant in the SIBO (P = 0.013) and Mixed SIBO/SIFO (P = 0.0001) groups. However, dysmotility was not a significant predictor for SIFO alone (P = 0.14).

>105 Analysis. Forty-nine of 80 (61%) patients with dysmotility had small bowel and/or fungal overgrowth based on bacterial concentration of >105 CFU/mL. A significant relationship (P = 0.005) was found between dysmotility and SIBO at this bacterial concentration threshold, and even when controlling for PPI use (Table 2). Patients with dysmotility had an odds ratio of 2.70 of having SIBO than those with normal motility.

Analyses done on each separate group (SIBO, SIFO and Mixed SIBO/SIFO vs. negative for dysmotility) were found to be significant in the Mixed SIBO/SIFO (P = 0.0003) but not SIBO (P = 0.13) or SIFO (P = 0.17) groups.

The Effects of PPI Use on Overgrowth

103 Analysis. Sixty-five of 150 (43%) patients with chronic GI complaints were using PPIs. Forty-nine of 65 (75%) patients on prolonged PPI therapy had small bowel bacterial and/or fungal overgrowth (Figure 3, Table 2). There was a significant relationship (P = 0.0063) between PPI use and small bowel bacterial overgrowth, irrespective of dysmotility. Patients taking PPIs had an odds ratio of 2.72 of having a small bowel bacterial overgrowth than those who were not taking PPIs.

Proton pump inhibitor use (P = 0.0063) was an independent and significant predictor for small bowel bacterial overgrowth (SIBO and/or SIFO) (Figure 3 and Table 2). Analyses were also performed for each separate group (SIBO, SIFO and Mixed SIBO/SIFO vs. negative for PPI use) and were found to be significant in the SIBO (P = 0.011) and Mixed SIBO/SIFO (P = 0.038) groups. However, PPI use was not a significant predictor for SIFO alone (P = 0.197).

105 Analysis. Forty of 65 (62%) patients on prolonged PPI therapy had SIBO or SIFO. There was a significant relationship (P = 0.008) between PPI use and SIBO, irrespective of dysmotility. (Table 2) Patients taking PPIs had an odds ratio of 2.46 of having SIBO than those who were not taking PPIs.

Analyses were also performed on each separate group (SIBO, SIFO and Mixed SIBO/SIFO vs. negative PPI use) and we found that there was a significant difference for the SIFO (P = 0.03) group and Mixed SIBO/SIFO (P = 0.03) group but not for the SIBO (P = 0.19) group.

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