Higher Lactobacillus Counts Research Articles

Effects of Lactobacillus strains on the ripening and organoleptic characteristics of Arzúa-Ulloa cheese

Seven batches of Arzúa-Ulloa, a short-ripened soft cow’s milk cheese produced in Galicia (NW Spain), were prepared from pasteurized milk. Two control batches of cheese (CB) were made with an acid-aromatic starter containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. lactis var. diacetylactis, isolated from raw-milk Arzúa-Ulloa cheeses. Five batches of cheese (LB) were made with the acid-aromatic starter plus one of five strains of mesophilic homofermentative Lactobacillus spp.: four of them isolated from raw-milk Arzúa-Ulloa cheese (characterized in previous works) and the remaining was a commercial Lactobacillus strain. Higher counts of mesophilic viable bacteria, lactic acid bacteria and citrate-fermenting bacteria were found on days 1 or 15 of ripening, while higher counts of lactobacilli were found on day 30 of ripening. On day 1 of ripening the highest diacetyl–acetoin content was noted in the CB, but after day 15 the diacetyl–acetoin content was similar or higher in three of the five LB. The mean degradation of β-casein in CB was higher than in LB, while the degradation of α s1-casein was higher in LB. The mean contents of nitrogen-soluble fractions were slightly higher in the LB than in the CB. Volatile free fatty acid (VFFA) contents were, in general, greater in LB than in CB and maximum amounts were determined on day 15 of maturation. Sensorial analysis indicated a more acid taste was in LB, while bitter and astringent tastes were more intense in CB. A positive correlation was found between β-casein degradation and bitter taste. Yogurt and butter aromas were more intense in CB and in two of the five LB. Firmness was lower in LB and a negative correlation was found between this parameter and α s1-casein degradation. Crumbliness showed a positive correlation with β-casein degradation. The use of the Lactobacillus strains assessed in this study is recommended for Arzúa-Ulloa cheese manufacture, in order to enhance the desirable characteristics of this cheese variety, i.e., a soft texture due to α s1-casein proteolysis but without the bitter taste due to β-casein degradation and a spicy and slightly rancid aroma and taste.

Decreasing prevalence of salivary lactobacilli in Swedish schoolchildren 1987-1998.

The prevalence and number of salivary lactobacilli was determined in all schoolchildren starting the 7th grade (12-13 yr; n = 1,578) in comprehensive school located in Kumla, Sweden between 1987 and 1998. Whole saliva samples were collected and transferred to dip-slides (Dentocult-LB) and incubated in room temperature for 7 d. Caries data were collected from the dental records and from bitewing radiographs. Both the number of lactobacilli and the prevalence of manifest caries and restorations exhibited a decreasing tendency and were significantly lower in 1998 than in 1987. The mean caries prevalence (DFS) declined from 5.2 to 1.8. In 1987, 45% of the children harboured high or very high lactobacilli counts ( > or =10(5) CFU/ml) in their saliva compared to approximately 10-15% at the later examinations. The proportion of children with no detectable counts varied between 4-29% during the study period, while children with low counts (10(3)-10(4) CFU/ml saliva) constituted a clear majority at the recent samplings. With such low levels in the population, the use of lactobacilli counts as a didactic tool in dietary counselling must be called into question.

Depressive symptoms favor abundant growth of salivary lactobacilli.

The purpose was to study the growth of lactobacilli in subjects with depressive symptoms in the total 55-year-old population of Oulu (a medium-sized town in Finland); 780 people participated. The dental examination included measurements of salivary lactobacillus growth with the Dentocult-LB method; measurements of salivary flow rate, pH, and buffering capacity; and assessment of oral health status. Depressive symptoms were determined with the Zung Self-Rating Depression Scale (ZSDS). Participants were also asked about their health, medication, smoking, and dietary habits. The prevalence of high lactobacillus counts (> or =100,000 CFU/ml) was 22% among women and 31% among men (p = .02). Thirty-seven percent of the subjects with a high rate of depressive symptoms (ZSDS score of > or = 40) and 23% of those with an ZSDS score of < or = 39 had high counts of lactobacilli (p = .003). A logistic regression analysis with improvement of goodness of fit was made to confirm the relation between abundant lactobacilli and a high rate of depressive symptoms. After the confounding factors had been added stepwise into the logistic regression model, depressive symptoms were still significantly associated with abundant lactobacillus growth. The association between high lactobacillus counts and depressive symptoms suggests that depressed subjects are at risk of having caries and possibly other dental diseases that should be recognized in the treatment of these patients.

The association of yeasts and denture stomatitis with behavioral and biologic factors

Objectives. This study describes the association of yeasts and denture stomatitis with behavioral and biologic factors. Study design. Seven hundred eighty 55-year-old citizens of Oulu, Finland, were examined clinically; 452 of them had complete dentures. Salivary yeasts and lactobacillus counts were detected through the use of Oricult-N and Dentocult-LB dip-slide techniques. Lifestyle factors were measured by means of questions concerning physical activity, tobacco smoking, alcohol consumption, and dietary habits. Other background variables used in cross-tabulations and logistic regression analysis were unstimulated salivary secretion rate, retention of denture, oral hygiene, gender, and socioeconomic status. Results. The prevalence of denture stomatitis was greater among subjects with an unhealthy lifestyle, subjects with higher lactobacillus counts, and subjects with poor oral hygiene. Salivary secretion rate and smoking were associated with the presence of yeasts, but general lifestyle measures were not. Conclusion. The presence of yeasts tended to be associated with biologic factors, but behavioral factors reflecting lifestyle may be more important in the development of denture stomatitis.

Relationship between hydrogen peroxide-producing strains of lactobacilli and vaginosis-associated bacterial species in pregnant women.

This study was conducted to determine the relationship between lactobacilli and bacterial species associated with bacterial vaginosis in pregnancy and the prevalence of H2O2-producing and non-producing strains of lactobacilli in pregnant women whose vaginal flora had already been analysed. Information was available for 174 pregnant women whose vaginal flora had been evaluated previously by examining gram-stained vaginal smears: 50 had grade III flora (bacterial vaginosis). 50 grade II flora, 41 flora graded as abnormal which then reverted to grade I (revertants) and 33 normal flora (controls). Lactobacilli were isolated from 19 of 50 women whose vaginal flora was grossly abnormal culturally and categorised as grade III by Gram staining. In 6 of these 50 women lactobacilli were isolated in large numbers, i.e. 10(5)-10(6) cfu/ml. H2O2-producing strains of lactobacilli were isolated from 11 of 12 women with grade III flora who were randomly selected from this group. Thus, in those 11 women it appears that H2O2-producing lactobacilli had not protected them from developing bacterial vaginosis. Bacterial species associated with vaginosis were isolated in high numbers from a large proportion of women in the revertant and grade II groups in association with high counts of lactobacilli. Thus, in some women it is possible that a change to an abnormal flora could occur before the complete disappearance of lactobacilli. It is concluded that bacterial vaginosis may develop in some women despite the presence of H2O2-producing strains of lactobacilli and that other factors, as yet unidentified, might be conducive to the appearance of abnormal bacterial flora with progression to vaginosis.

Oral glucose clearance in nonagenarians in relation to functional capacity, medication and oral variables.

To study oral sugar (glucose) clearance and to examine some factors which were believed to either influence or be dependent upon oral glucose clearance. Cross-sectional, clinical study with analysis of records. Göteborg gerontological and geriatric population studies, Göteborg University, Sweden. 71 community-dwelling individuals, 27 men and 44 women, of a representative sample of 260 92-year-old persons. Glucose concentration was measured in saliva after chewing of a glucose tablet and the clearance was assessed by three different variables: (i) the initial salivary glucose concentration, (ii) the area under the curve (AUC) and (iii) the clearance time. The glucose clearance showed a wide inter-individual variation, which could be explained partly by differences in oral state, chewing time, stimulated salivary secretion rate and medication use. A positive correlation was found between the clearance variables and the number of lactobacilli and mutans streptococci in saliva and the percentage of untreated root caries lesions of the total number of exposed root surfaces. A slow oral sugar clearance is more common among 92-year-olds than younger adults earlier reported in other studies, particularly in those who have uncompensated functional impairments and a high medication history. A decreased oral glucose clearance was associated with high counts of salivary lactobacilli and mutans streptococci and a high proportion of untreated root caries lesions.

Controlled study of the association of smoking with lactobacilli, mutans streptococci and yeasts in saliva.

The effect of smoking on salivary microbe levels was studied in 780 subjects by multivariate analysis, taking into account some confounding factors. Lactobacilli, mutans streptococci and yeasts were detected with Dentocult-LB, Dentocult-SM and Oricult-N tests. The explanatory variables considered were gender, presence of natural teeth, presence of removable denture, presence of decayed teeth, toothbrushing frequency, use of sugar in coffee or tea, consumption frequency of sugary products, secretion rate of stimulated and unstimulated saliva, buffering capacity of saliva, pH of saliva, oral hygiene and tobacco smoking habits. Smoking was strongly associated with higher lactobacilli counts and presence of yeasts, independently of oral status, hygiene or salivary factors. The relation between smoking and mutans streptococci was weaker. The overall associations of lactobacilli and yeasts with the study variables followed a very similar pattern.

Effects of compliance with fluoride gel application on caries and caries risk in patients after radiation therapy for head and neck cancer

The use of fluoride gel applied in a custom tray once daily has become standard for patients who have xerostomia after undergoing radiation therapy. Compliance may be poor as a result of the inconvenient method of application and because many patients with head and neck cancer have poor health behaviors. Our aim was to investigate the effect of compliance with fluoride gel application on caries and caries risk. Patients were prescribed neutral sodium fluoride gel (5000 ppm) before undergoing radiotherapy Fifty-two patients were willing to visit the dental clinic for dental examination, measurement of saliva, and quantitative culture of Streptococcus mutans and lactobacillus species. Before radiotherapy was performed, decayed, missing, and filled surfaces data were recorded for all patients in the study. Of these patients, 27 used fluoride gel once daily, as directed. Radiation dose, number of fractions, and duration of radiation had a significant inverse effect on postradiotherapy whole resting saliva (p = 0.04, p = 0.01, and p = 0.01) and on whole stimulated saliva (p = 0.02, p < 0.01, and p < 0.01). Patients with a subjective feeling of dry mouth had significantly less saliva production at rest (p = 0.01) and on stimulation (p = 0.01). A trend toward reduction of S. mutans counts was seen in those patients who used their fluoride gel regularly (p = 0.057). High lactobacilli counts were found in the patients with high and low compliance with fluoride gel use. Differences in the mean caries incidence between those who reported compliance with daily fluoride application and those who did not comply were not found significant because of the large SD in the patient groups, although differences in the mean for these groups were seen. The lack of a statistically significant difference may be due to the multiple factors associated with caries. Therefore patient care must be individualized, and patients must be assessed at regular intervals to determine the caries risk and caries activity to provide guidance for maintenance of the dentition.

Caries prevalence and salivary and microbial conditions in 88-year-old Swedish dentate people.

As part of a comprehensive investigation of 88-year-old people, caries prevalence, stimulated salivary secretion rate, buffer capacity, and the prevalence of lactobacilli and mutans streptococci were studied in a subsample of 92 dentate subjects. The mean number of remaining teeth was 14.1 +/- 7.3. The DMFT was 25.2 +/- 3.0, and DF surfaces 38.3 +/- 22.7. Root caries experience was found in 85% of the subjects, with a mean root caries index of 36.6 +/- 28.5%. The men had significantly higher mean values of salivary secretion rate (2.0 +/- 1.3 ml/min) than the women (1.1 +/- 0.6 ml/min) (p < 0.001). The mean final pH of buffer capacity was 6.3 +/- 1.3. High counts of lactobacilli (> 10(5)) and mutans streptococci (> 10(6)) were found in 49% and 55% of the subjects, respectively, of whom most were denture wearers. The mean number of total mutans streptococci was higher in persons harboring both Streptococcus mutans and S. sobrinus than in subjects with only S. mutans.

Mutans streptococci and lactobacilli in the elderly

The prevalence of salivary mutans streptococci and lactobacilli, salivary flow rate, and the type of dentition were studied in connection with a medical survey of 76-, 81-, and 86-yr-old inhabitants of Helsinki living at home. High bacterial counts were associated with low salivary flow rates. High counts of mutans streptococci (> 10(6) CFU/ml) were found in 68% of wearers of full dentures, as compared with 53% of subjects having natural teeth. High counts of lactobacilli (< 10(6) CFU/ml) were found in 44% of subjects having removable partial dentures and in 39% of subjects having natural teeth. The bacterial counts correlated neither with medicines taken daily nor with diseases among this population.

Influence of salivary levels of mutans streptococci on colonization of crown margins: A longitudinal study

Initial colonization of mutans streptococci in 36 crown margins of 21 patients was studied. Before cementation, salivary concentrations of mutans streptococci and Lactobacillus sp, microorganisms associated with dental caries, were determined. Within 1 week 25% of the selected crown margins in subjects with low salivary levels of mutans streptococci and 89% in subjects with high salivary levels were colonized. High salivary counts of lactobacilli seemed to reflect conditions that enhanced the risk of colonization of mutans streptococci. The results suggest that, before cementation of fixed prosthodontics, measures should be taken to control the salivary concentrations of these organisms to reduce the susceptibility to recurrent caries.

Dietary and salivary factors associated with root caries.

In this pilot study, dietary habits, microbial factors, and salivary factors in 20 older adults who had active decay on root surfaces were compared with those of 20 adults who had inactive or no root caries. In this case-control study, the groups were matched by sex and were of similar age. Subjects using medications known to induce dry mouth were excluded. Subjects completed a nutrition interview and a four-day food diary. Stimulated whole saliva flow rate, buffering capacity, levels of salivary lactobacilli with use of the Dentocult method, and S. mutans cultured on MSB agar were determined. The root caries group had a greater mean number of eating occasions per day (6.1 vs. 4.6), more frequent exposures to fermentable carbohydrates (5.8 vs. 4.2), and higher average daily sugars intake (133 g/day vs. 105 g/day) than the control group. Root caries subjects had significantly higher lactobacilli counts and less salivary buffering capacity. Within the root caries group, significant correlations were found with Root Caries Index and lactobacilli (r = 0.56) and S. mutans counts (rs = 0.50). These results show that frequent intake of simple sugars, high lactobacilli counts, and low saliva buffering capacity may be risk factors associated with root caries in older adults.

Observations on bacteria associated with pigeon crop

Lactobacilli, streptococci and coliforms of pigeon crop contents, 5th wash, macerate and those of first-day pigeon milk have been studied. Streptococci predominated in all the samples tested. Relatively higher counts of lactobacilli and streptococci in crop macerate than in the 5th wash suggested the adhesion of these bacteria to crop wall. Because of frequent occurrence in crop of partially digested fibrous food, its contents were tested for the presence of cellulolytic bacteria. The results indicated that four isolates were capable of utilizing cellulose with the resultant production of reducing sugars. It is inferred that the crop microflora is involved in the degradation of dietary fibre in the pigeon.

Lactic acid and pH as indicators of spoilage for vacuum-packed cooked ring sausages

Lactic acid production and pH changes of 206 vacuum-packed cooked ring sausages stored at 2, 4 and 12°C from 21 different production runs were monitored as a function of time and of microbial growth. The total lactic acid concentrations and pH values were first at a constant level, starting to increase sharply after the lactobacilli count reached about 5 × 10 7 or 6 × 10 7 cfu/g, respectively. The lactic acid and pH changes as a function of the lactobacilli count were similar at 4 and 12 ° C. The sharp increase at high lactobacilli counts was observed in both L-lactic acid and D-lactic acid. The variation was lesser and the increase greater in D-lactic acid formation than in L-lactic acid. Above a level of 3–4 mg lactic acid/g most of the samples were deemed unfit. The pH started to decrease from a level of approx. 6.3; below 5.8–5.9 the samples were deemed unfit. The lowest pH value observed was 4.58. Both a high lactic acid content and a low pH indicated that the sausage was spoiled. These changes, however, took place at later stages of storage, and do not give information about the early phase of spoilage.

Mutans streptococci, lactobacilli and caries prevalence in 11- and 12-year-old Icelandic children.

Since the caries prevalence has not declined in Iceland as it has in other European countries, it was of interest to study the presence of cariogenic bacteria in Icelandic children. The prevalence of salivary mutans streptococci and lactobacilli was examined in 217 11- and 12-yr-old Icelandic children and was related to their caries prevalence. In 2% of the children mutans streptococci were not found whereas 31% and 35% of the 11-yr-olds and 12-yr-olds respectively carried more than 10(6) CFU per ml saliva. Lactobacilli were not detected in 8% of the children whereas 28% of the 11-yr-olds and 23% of the 12-yr-olds had more than 10(5) CFU per ml saliva. The mean caries prevalence (DFS), initial caries included, for 11-yr-olds was 21.6 and for 12-yr-olds 28.8. Both mutans streptococci and lactobacilli were significantly correlated to each other as well as to caries prevalence. An increased number of these microorganisms, especially the mutans streptococci, were associated with an increased DFS. Children with high salivary counts of mutans streptococci and lactobacilli showed four times higher DFS than children with low numbers. The magnitude of salivary cariogenic bacteria as well as caries prevalence was found to resemble the situation in Sweden 10 yr ago. S. mutans (serotype c/e/f) was carried by all mutans streptococci positive children. S. sobrinus (serotype d/g) was found in 60 children (30.2%). Children with both S. mutans and S. sobrinus had significantly higher salivary counts of mutans streptococci and lactobacilli as well as caries prevalence than children with only S. mutans.

Stimulated saliva and microbial growth in older adults

SummaryThe flow rate, pH, buffering capacity, and viscosity of stimulated whole saliva of 54 noninstitutionalized older people were determined. The subjects all wore removable dentures, complete or partial, and were 73 years old and older. The salivary flow rate of the men was found to be higher than that of the women, and particularly low buffering capacity values were observed in the men. Seventy percent of this population used one or several medications. Those subjects using medications had a decreased flow rate and an increased salivary viscosity. The occurrence of high Lactobacillus and yeast counts was connected with the low flow rate and the high viscosity of saliva.

Lysozyme activity and L(+)-lactic acid production in saliva in schoolchildren with high Lactobacillus counts.

Out of 374 schoolchildren, aged 13-15 yr, 42 with high counts of salivary lactobacilli (greater than or equal to 10(5] were selected for this study. Lysozyme activity in saliva and L(+)-lactic acid (LA) production after addition of glucose were determined. The mean values of lysozyme activity and LA concentration were 19.4 micrograms/ml and 1.4 mmol/l respectively. The levels of LA produced without addition of glucose were less than 0.2 mmol/l. The results showed a statistically significant (P less than 0.05) negative correlation between lysozyme activity and the levels of LA produced. The findings of this study suggest that lysozyme may be of importance in limiting acid production in saliva.

An attempt to motivate improved sugar discipline in a 12-year-old high caries-risk group.

Twelve-yr-old high caries-risk children were identified by a low buffer capacity and high lactobacillus counts in stimulated saliva. A defined and standardized counselling technic was used, by which the children were recommended to reduce their sugar consumption. Seven weeks later the lactobacillus count in saliva was reduced to an acceptable level in 79%. The caries increment decreased by 66% over 1 yr.

Prediction of root surface caries in patients treated for advanced periodontal disease.

The present investigation was undertaken (1) to analyze the prevalence of root surface caries prior to and after periodontal treatment and (2) to determine the feasibility of using simple clinical criteria for predicting a patient's risk of developing root surface caries following periodontal therapy. Thirty-one patients were given advanced periodontal treatment including periodontal surgery. At baseline they were examined for oral hygiene status, root surface caries experience and number of lactobacilli per ml saliva as evaluated by the Dentocult dip-slide method. Follow-up examinations 1, 2 and 4 years after baseline showed that a majority of the patients were treated successfully and maintained in periodontal health. Root surface caries developed in approximately two-thirds of the patients during the 4-year observation period. However, the total increment of root lesions during these years was mostly extremely low, i.e. less than 5% of exposed root surfaces. In higher risk patients developing new root surface caries, significant correlations were demonstrated with initial pretreatment scorings from (1) their previous root surface caries experience, (2) high lactobacillus counts and (3) advancing age. In addition, root surface caries incidence and low saliva secretion rats were found to correlate significantly during the course of the study.

トマトジュース寒天培地"栄研"を用いての学童の乳酸菌数測定

Oral examination and lactobacillus counts were conducted on a selected group of one hundred school children, and the results obtained were summarized as follows. 1. In 58.3 to 60.2 percents of subjects with carious teeth there were found far higher lactobacillus counts than in subjects with healthy teeth. The mean lactobacillus count in the mouth of the former amounted as much as 3-fold that in the mouth of the latter. 2. There was hardly found any significant correlation between the number of decayed teeth and lactobacillus count. However, the mean lactobacillus counts proved to be generally elevated in subjects having high caries incidence. 3. The mean lactobacillus count in the regular users of tooth-brush proved to be lower than that in non-users.