This study attempts to develop a reference substance for the live bacteria count of Streptococcicosis live vaccines in order to evaluate the validity of live bacterial count in inspection and testing. We prepared a batch of live Streptococcus suis reference substance for live bacterial count, tested their physical property, purity, vacuum degree, remaining moisture, and determined their homogeneity, thermal stability and transportation stability. Moreover, we organized collaborative calibration to assign count values to the reference substance and determine the shelf life of the reference substance in 12 months. The results showed that the physical property, the purity, the remaining moisture and the vacuum degree of the reference substance were all in compliance with the requirements of the Chinese Veterinary Pharmacopoeia. The homogeneity test showed that the coefficient of variation of the count of the reference substance was less than 10%, indicating a good homogeneity. Transportation stability test showed that the reference substance remained active after 72 h transportation in summer and winter with the package of styrofoam boxes and ice packs. Thermal stability test showed that the reference substance could be stored for up to 3 months at -20 °C, or up to 21 days at 4 °C. According to the collaborative calibration, the reference vaccine was assigned a count value range of (8.5-12.1)×107 CFU/ampoule. The shelf life test showed that the reference substance was stable for 12 months when stored at -70 °C. The reference substance could provide a reference for the live bacterial count of Streptococcicosis live vaccines. Moreover, it could also be used as a reference to evaluate the quality of corresponding agar media.
Bacterial Load ; Reference Standards ; Vaccines, Attenuated

The efficacies of six commercial disinfectants were evaluated by using Salmonella enterica serovar Typhimurium under simulated natural conditions such as sub-zero temperature, short disinfecting time, and surface type (uneven or smooth). We used a suspensionmodel test to determine the disinfecting efficacy under varying contact times (1, 5, 10, and 30 min) and temperatures (25℃, 4℃, 0℃, and −10℃). The bactericidal effect according to surface structure was measured by using a carriermodel test at 25℃ and −10℃. The effective concentrations of each disinfectant were fixed to give a disinfecting effect within a short time (< 1 min) at 25℃ and −10℃. The suspension model results revealed that bactericidal efficacy significantly dropped at low temperature for most of the disinfectants used; a sodium dichloroisocyanurate product showed the strongest efficacy. In the carrier test, bacterial load on a wooden surface was more difficult to remove than that on a stainless-steel surface. The results show that commercial disinfectant products vary in their disinfecting efficacy, which is affected by several field factors including temperature, contact time, and carrier material. Environmental conditions and surface type for disinfection should be considered prior to selecting an optimal disinfectant in the field.
Bacterial Load ; Disinfectants* ; Disinfection ; Salmonella enterica* ; Salmonella* ; Serogroup* ; Sodium

The purpose of this study was to assess the efficacy of photodynamic therapy (PDT) using erythrosine and a halogen light source to treat a biofilm formed on a machined surface titanium disk in vivo. Ten volunteers carried an acrylic appliance containing six machined surface titanium disks on the upper jaw over a period of five days. After the five days of biofilm formation period, the disks were removed. PDT using 20 microM erythrosine and halogen light was then applied to the biofilms formed on the disks. Experimental samples were divided into a negative control group (no erythrosine and no irradiation), E0 group (erythrosine 60s + no irradiation), E30 group (erythrosine 60s + halogen light 30s), and E60 group (erythrosine 60s + halogen light 60s). Following PDT, the bacteria in the biofilm were found to be detached from each disk. Each suspension with detached bacteria were diluted and cultivated on a blood-agar plate for five days under anaerobic conditions. The cultivated bacterial counts in the E60 group were significantly lower than the control group (86.4%) or E0 group (76.7%). In the experimental groups also, the light exposure time and bacterial counts showed a negative correlation. In conclusion, PDT using erythrosine and halogen light has bactericidal effects on biofilms formed on a titanium disk in vivo. Notably, applying 20 microM erythrosine and 60 seconds of halogen light irradiation had a significantly potent effect.
Bacteria ; Bacterial Load ; Biofilms ; Erythrosine ; Jaw ; Light ; Photochemotherapy ; Titanium ; Triazenes

OBJECTIVETo study the bacterial culture results of expressed breast milk.

METHODSA total of 1178 expressed breast milk samples were collected for bacterial culture. The breast milk sampled from the mothers of preterm neonates (n=615) and term neonates (n=563) who were hospitalized between May 2014 and April 2015.

RESULTSThere was no significant difference in bacterial counts between the preterm and term sample groups (P>0.05). Potential intestinal pathogens were found in 55 samples (4.63%) of the 1178 samples, with no significant difference between the preterm and term sample groups (P>0.05). The second expressed milk samples from 33 mothers were cultured. Only 10 samples (30%) were found to have the same bacteria as the first time. The detection rate of bacterial load of ≥ 10⁵ CFU/mL was higher in those samples with potential intestinal pathogens, as compared with those samples without potential intestinal pathogens (43.64% vs 14.87%; P<0.05). There was no correlation between the incidence of neonatal infections and potential intestinal pathogens in breast milk.

CONCLUSIONSBreast milk is not sterile. Bacterial loads and phylotypes are variable. Random breast milk cultures can neither describe bacterial colonies in breast milk, nor be a predictor of neonatal infection.

To evaluate the efficacy of polygexamethylene biguanide(PHMB) in Pseudomonas aeruginosa(P. aeruginosa) keratites model, 10microliter of P. aeruginosa bacterial suspension(1x103 colony-forming unit(cfu)/ml) was injected intrastromally into rabbit corneas. Eighteen rabbits(36 eyes) were divided into three treatment groups: balanced salt solution(BSS) group(N=18 eyes). PHMB(0.02%, 200microliter/ml) group(n=9 eyes), tobramycin(14microliter/ml) group(n=9 eyes). Topical antibiotic drops were given hourly from 12 hours after inoculation. A subconjunctival infection was every 24 hours during the first 72 hours. The Severity of keratitis was scored in basked fashion every 8 hours. Corneal buttons were excised and homogenized at the end of the study to determine the viable bacterial counts. In P. aeruginosa keratitis model, tobramycin was statistically more efficacious than PHMB, according the clinical scores at 58 hours(9.9 vs. 15.1, P<0.0001) and log10 cfu(0.54+/-0.21 vs. 4.87+/-1.07. P<0.0001). No differences were found between the PHMB and BSS groups in either clinical scores or bacterial counts. PHMB appears to be ineffective against P. aeruginosa in experimental keratitis model of rabbit.
Bacterial Load ; Cornea ; Keratitis* ; Pseudomonas aeruginosa* ; Pseudomonas* ; Tobramycin

OBJECTIVE: It is important to sterilize oral cavity with antibacterial agent before surgery for preventing infection. The object of this study was to compare the effect on reduction of salivary bacterial counts according to applied time when povidone-iodine (PVI) and chlorhexidine gluconate (CHX), most broadly used materials in dentistry, were applied intraorally before the surgery. METHODS: Sixty subjects were divided into 6 groups. PVI and CHX were applied in each group for 1, 2 and 3 minutes, respectively. Then salivary microbacteria taken before and after applying the materials were cultured using 5% sheep blood agar plate. RESULTS: There was significant difference in reduction of microbacteria in both PVI and CHX and the effect did not show differences depending on time. When applied for a minute, PVI showed somewhat higher reduction rate than CHX, but in the other groups, there was no difference in reduction rate. CONCLUSION: We found that there was no significant difference in sterilization ability of PVI and CHX in all groups in this study. Therefore, both agents would get sufficient effect when applied for a minute.
Agar ; Bacterial Load ; Chlorhexidine ; Dentistry ; Mouth ; Povidone-Iodine ; Sheep ; Sterilization

OBJECTIVE: It is important to sterilize oral cavity with antibacterial agent before surgery for preventing infection. The object of this study was to compare the effect on reduction of salivary bacterial counts according to applied time when povidone-iodine (PVI) and chlorhexidine gluconate (CHX), most broadly used materials in dentistry, were applied intraorally before the surgery. METHODS: Sixty subjects were divided into 6 groups. PVI and CHX were applied in each group for 1, 2 and 3 minutes, respectively. Then salivary microbacteria taken before and after applying the materials were cultured using 5% sheep blood agar plate. RESULTS: There was significant difference in reduction of microbacteria in both PVI and CHX and the effect did not show differences depending on time. When applied for a minute, PVI showed somewhat higher reduction rate than CHX, but in the other groups, there was no difference in reduction rate. CONCLUSION: We found that there was no significant difference in sterilization ability of PVI and CHX in all groups in this study. Therefore, both agents would get sufficient effect when applied for a minute.
Agar ; Bacterial Load ; Chlorhexidine ; Dentistry ; Mouth ; Povidone-Iodine ; Sheep ; Sterilization

BACKGROUND: The endotracheal suction was one of the critical requirements for severe neurosurgical patients in the prevention of the airway-obstruction, pneumonia, atelectasis, and so on. There were two types of suction methods, closed and open. In the literature, many reported the comparison of the two methods with variable factors, yet, it was still controversial. In this study, we compared the two types of endotracheal suction methods based on the pattern of the sputum cultivation, which was not discussed in the previous studies. METHODS: In 2010, 85 patients who had intubation tube for more than 10 days were evaluated in this study. A total of 55 patients were managed with an open suction method, while the other 30 patients were managed with a closed suction method. All patients' sputum culture was reported semi-quantitatively, and had been classified into 3 different groups, according to the culture pattern. The control group was defined in which the bacterial count was not increased, whereas the non-control group was those with bacterial count increased. We investigated patients' age, gender, disease-type, suction techniques and the pattern of sputum cultivation. RESULTS: The non-control group was 45.45% in the open suction group, while it was 16.67% in the closed suction group. On the other hand, more control group was observed in the closed suction group (36.67%), than in the open suction group (25.45%) (p < 0.05). There was no statistically significant difference in the analysis based on the pattern of sputum cultivation, age, gender, and disease-type. CONCLUSIONS: We suggest that the closed suction methods were more effective in the management of endotracheal tube, according to the pattern of sputum culture.
Bacterial Load ; Hand ; Humans ; Intubation ; Pneumonia ; Pulmonary Atelectasis ; Sputum ; Suction

To evaluate the efficacy of oplyhexamethylene biguanide(PHMB) in Staphylococcus aureus (S. aureus) keratitis model, 10microliter of S. sureus bacterial suspension(1x10(5) colony-forming unit(cfu)/ml) were infected intrastromally into rabbit corneas. 18 rabbits were divided into three treatment groups : balanced salt solution (BSS) group(n=18 eyes), PHMB(0.02%, 200microgram/ml) group(n=9), cefazolin(40 microgram/ml) group(n=9). Topical antibiotic drops were given hourly starting at 24 hours after inoculation. A subconjunctival injection was given every 24 hours for the study duration(96 hours). The severity of keratitis was scored in masked fashion every 12 hours. Corneal buttons were excised and homogenized at the end of the study to determine viable bacterial counts. In the S. aureus keratitis model, there was no difference of clinical scores between BSS, cefazolin, PHMB group at 72 hours, and the number of viable bacteria recovered from the corneal button in log(10) cfu was 2.65+/-1.85, 3.30+/-0.85, 2.86+/-1.36, in BSS, cefazolin, PHMB group respectively. No differences in either clinical scores or bacterial counts were found between the PHMB and BSS groups. PHMB appears to be ineffective against S. aureus in this model of experimental keratitis.
Bacteria ; Bacterial Load ; Cefazolin ; Cornea ; Keratitis* ; Masks ; Rabbits ; Staphylococcus aureus* ; Staphylococcus*

Selected number of urinary E. coli isolates from patients were subjected to the tests to characterize in vitro properties, compared with the strains of normal flora in intestinal tract or other sources. Further studies were carried out for determination of the mechanism of pathogenesis by using rabbit as an experimental animal model. Both strains of 87E1 and 87E51 which had one type of pili, were eliminated rapidly 4 or 8 days after inoculation into renal pelvis of rabbit. On the contrary, 88E18 strain which had both types of pili successfully colonized in urinary tract and the rabbit died due to urosepsis after the 8th day of experiment. The result of bacterial count colonized in the tissue by colony forming unit (CFU)per gram were similar to those in the urine.
Bacterial Load ; Colon ; Humans ; Kidney Pelvis ; Models, Animal ; Stem Cells ; Urinary Tract ; Uropathogenic Escherichia coli* ; Virulence*