Difference In Bacteria Counts Research Articles

Live and Dead Bacteria Counts of Different Yogurts Before and After Expiration

Abstract Objectives The objective of this study was to investigate differences in live and dead bacteria counts a month before the expiration date and right after the expiration date and observe any differences in bacteria counts between types of yogurt, brands, and stores tested. Methods Two yogurt containers with the same expiration date were collected for each brand at three stores. The yogurts collected were three national brands of Greek yogurts and five regular yogurts. The first container was tested one month prior to expiry. The second container was tested at the expiration date. After being thoroughly mixed, triplicate 50–75 mg of yogurt were sampled from each carton. Yogurt samples were diluted 9-fold with freshly prepared peptone water. A second dilution was prepared by mixing 25 µL of the yogurt peptone mix with 975 µL of freshly prepared sterile PBS. The samples were incubated for 15 min. at 37°C with 1 µL SYBR green and 5 µL propidium iodine and iced for 1 hour in the dark. 200 µL of dyed yogurt were diluted with 800 µL of PBS and analyzed by flow cytometer (BD Accuri™ C6 Cytometer). Each yogurt sample was run in triplicate on slow speed setting. Flow cytometer parameters were set to differentiate live and dead bacteria based on fluorescence as well as yogurt matrix artifacts. The data was analyzed by a least-squares fit model to test for significance among variables. Results Greek yogurts had significantly higher live and dead bacteria counts compared to regular yogurts. The Greek yogurts differed amongst themselves. Brand 3 had significantly lower live counts than brand 2 and 1. Brand 1 had significantly higher counts of dead bacteria compared to the other two. While differences between Greek yogurt are statistically significant, they are most likely not clinically significant. For the regular yogurt live and dead counts there were no significant differences. No significant differences were observed based on the timing of yogurt sampling or the store the yogurt came from. Conclusions Preparing Greek yogurt involves more straining and whey removal and yields a higher yogurt concentration, so it is no surprise that Greek yogurts have higher bacteria counts. This study demonstrates that when considering yogurt for its probiotic qualities, the most relevant factor is the type of yogurt. Yogurt brand, store, or when it is sampled have little effect on the probiotics count. Funding Sources USU.

Microbial Assessment of In-door Air and Equipment Used in Banks within Ekiti State University, Ado-Ekiti, Ekiti State, Nigeria

Banking activities which involve the use of counting machines, Automated teller machines, and exchange of naira notes play potential roles in the spread of infectious microorganisms. This study aimed at determining the microbial status of banks within Ekiti State University campus. A total of 96 samples were collected from six different banks’ in–door air, ATM, counting tables and Money counting machines in Ekiti State University campus. The samples were collected both in the morning and afternoon. Bacteria and fungi were isolated from the samples using serial dilution and pour plating methods. The isolates were identified based on morphological and biochemical characterization. Susceptibility pattern of the isolates to different classes of antibiotics (Penicillins, Quinolones, Macrolides, Aminoglycosides, Fluoroquinolones and Sulfonamides) were determined using agar disc diffusion method. There was significant difference (p<0.05) in bacteria counts on all the equipment analyzed in all the banks except Heritage bank. Analysis of variance also revealed significant difference in the bacteria counts from the banks in the morning and in the afternoon (p<0.05). Bacteria and fungi isolated from the samples belonged to the genera Staphylococcus, Streptococcus, Enterobacter, Klebsiella, Escherichia Serratia, Pseudomonas, Proteus Bacilllus, Aspergillus, Alternaria, Mucor and Fusarium where bacteria group dominated with 65% while their fungal counterparts were 35% of the total isolates. Escherichia coli had the highest percentage occurrence of 18.6%, followed by Staphylococcus aureus (15.2%) while Proteus sp. had the lowest occurrence (1%). The isolates exhibited resistance to Augmentin (100%), Erythromycin (100%), Amoxycillin (96%), Cotrimoxazole (96%), Chloramphenicol (86%), Streptomycin (72%) and Gentamycin (58%) while their growths were inhibited by Ciprofloxacin, Ofloxacin, Prefloxacin and Septrin. Plasmid analysis of the resistant strains showed that the isolates lack plasmids. The presence of potential pathogens in the banks and multiple antibiotic resistance displayed by the isolates constitutes risk to the public health. Hence, measures such as thorough hand washing with soap and hand sanitization after using the bank and its facilities should be emphasized.

Perioperative changes in oral bacteria number in patients undergoing cardiac valve surgery.

Perioperative oral care can reduce the risk of postoperative infections. This study examined 1) changes in oral bacteria counts during the perioperative period and 2) differences in bacteria counts in patients with or without endotracheal intubation. 47 patients who visited our hospital dental clinic prior to cardiac valve surgery were prospectively recruited. The number of bacteria on the tongue, tooth surface, and buccal vestibule was measured on the day before and 1, 4, and 7 days after surgery. Oral bacteria counts were statistically compared among time points and between intubation and extubation statuses. The oral bacteria counts on the tooth surface and buccal vestibule significantly increased from the day before surgery to 1 day after surgery, and then decreased from 1 to 4 days after surgery. On the day after surgery, the bacteria counts on the tooth surface and buccal vestibule were significantly higher in the intubated compared with the extubated group. Our findings suggest that the oral bacteria count is elevated just after surgery, especially if the patient has endotracheal intubation, which may increase the risk of aspiration pneumonia. These results highlight the importance of perioperative oral care to prevent postoperative pneumonia.

Microbial Evaluation of Traumatized Teeth Treated with Triple Antibiotic Paste or Calcium Hydroxide with 2% Chlorhexidine Gel in Pulp Revascularization

IntroductionRevascularization outcome depends on microbial elimination because apical repair will not happen in the presence of infected tissues. This study evaluated the microbial composition of traumatized immature teeth and assessed their reduction during different stages of the revascularization procedures performed with 2 intracanal medicaments. MethodsFifteen patients (7–17 years old) with immature teeth were submitted to the revascularization procedures; they were divided into 2 groups according to the intracanal medicament used: TAP group (n = 7), medicated with a triple antibiotic paste, and CHP group (n = 8), dressed with calcium hydroxide + 2% chlorhexidine gel. Samples were taken before any treatment (S1), after irrigation with 6% NaOCl (S2), after irrigation with 2% chlorhexidine (S3), after intracanal dressing (S4), and after 17% EDTA irrigation (S5). Cultivable bacteria recovered from the 5 stages were counted and identified by means of polymerase chain reaction assay (16S rRNA). ResultsBoth groups had colony-forming unit counts significantly reduced after S2 (P < .05); however, no significant difference was found between the irrigants (S2 and S3, P = .99). No difference in bacteria counts was found between the intracanal medicaments used (P = .95). The most prevalent bacteria detected were Actinomyces naeslundii (66.67%), followed by Porphyromonas endodontalis, Parvimonas micra, and Fusobacterium nucleatum, which were detected in 33.34% of the root canals. An average of 2.13 species per canal was found, and no statistical correlation was observed between bacterial species and clinical/radiographic features. ConclusionsThe microbial profile of infected immature teeth is similar to that of primarily infected permanent teeth. The greatest bacterial reduction was promoted by the irrigation solutions. The revascularization protocols that used the tested intracanal medicaments were efficient in reducing viable bacteria in necrotic immature teeth.

Influence of season, ambient temperature, and time until feeding on bacteria counts in pasteurized milk for dairy calves

Pasteurization of waste milk fed to calves is increasingly common. The primary objectives of this study were to evaluate milk bacteria counts as time passed following on-farm pasteurization and identify potential differences in bacteria counts over time between seasons and the associated ambient temperatures. A secondary objective was to evaluate, by season, the time after pasteurization until milk bacteria counts became &gt; 20,000 cfu/mL, which has been suggested as an industry-standard upper limit for feeding milk to calves.

An experimental study: the effect of Periprosthetic high glucose environmental condition on Staphylococcus infection

Objective To evaluate the effect of periprosthetic high glucose environment on the growth of Staphylococcus and bacterial biofilm formation. Methods New Zealand white rabbits were used to establish the animal model of prosthetic infection. There were staphylococcus aureus group (SA, n=40) and Staphylococcus epidermidis group (SE, n=60). Each group were randomly divided into the experimental group and control group. The bacteria were injected with 0.1ml l%glucose into the knee of rabbits in experi-mental group; the rabbits were injected with 0.1ml normal saline in the control group. The SA group were observed in the 2,4,6 and 8 days; The SE group were observed at 2,4,6,8,12 and 16 days. Bacterial counts, scanning electron microscopy and histological observations were used to the changes. Results In the SA group, there was no difference in bacteria counts of synovial fluid between the experimental group and control group 2 days after injection (P=0.426). But 4,6 and 8 days after injection ,the bacteria counts of synovial fluid in the experimental group increased significantly. Scanning electron microscopy found On the day of 2,4,6, the number of bacteria adhere to the prosthetic surface had increased significantly in experi-mental group, compared with the control group.The bacterial biofilm formed significantly. Histological exami-nation revealed that the bacteria were found in the tissue surrounding prosthesis two days after injection,but not in the control group. In SE Group no difference was found in bacterial counts of synovial fluid between the experimental group and control group after 2,4,6,8,12 and 16 days after injection,as well as the num-ber of bacteria adhere to the prosthetic surface Histological examination revealed that no bacteria was found in the tissues around prosthesis in two groups. Conclusion High glucose environment has significant effect on prosthetic infection by Staphylococcus aureus, but not those caused by Staphylococcus epidermidis. Key words: Knee prosthesis; Infection; Staphylococcus aureus; Staphylococcus epidermidis; Glucose

Gelatin-Sealed Dacron Graft is not more Susceptible to MRSA Infection than PTFE Graft

The purpose of this experimental study was to compare the susceptibility of gelatin-sealed Dacron and PTFE prostheses to infection by MRSA. Prospective, randomized, controlled animal study. Graft infections were established in the subcutaneous tissues of 60 female Spraque-Dawley rats by the implantation of gelatin-sealed Dacron or PTFE prostheses followed by topical inoculation with methicillin-resistant Staphylococcus aureus. The study groups were as follows: (1A) uncontaminated gelatin-sealed Dacron group, (1B) untreated contaminated gelatin-sealed Dacron group, (1C) contaminated gelatin-sealed Dacron group with intraperitoneal teicoplanin treatment, (2A) uncontaminated PTFE group, (2B) untreated contaminated PTFE group, and (2C) contaminated PTFE group with intraperitoneal teicoplanin treatment. The grafts were removed after 7 days and evaluated for infection by counting the number of adherent bacteria on the graft material after rinsing and sonication. The perigraft tissue was harvested for histopathological study. To investigate the existence of any infection, blood samples were collected by cardiopuncture for a culture analysis. No significant difference in bacteria counts was observed between gelatin-sealed Dacron and PTFE grafts. In groups 1A and 2A, there was no infection detected. The bacterial counts for MRSA were 7.4 x 10(5) in group 1B and 8.6 x 10(5) in group 2B. There was also no infection in groups 1C and 2C. While the difference between group 1B and 2B was not significant (p>.05), bacterial counts in group 1B or 2B were significantly higher than those in other groups. Blood cultures were only positive in four rats in group 1B and in two rats in group 2B. The severities of the inflammation of the perigraft tissues was low in groups 1A and 2A, high in groups 1C and 2C, and between the range from low to moderate in groups 1B and 2B. The susceptibility of gelatin-sealed Dacron to bacterial infection was not higher than that of PTFE.

Stream Water Quality as Influenced by Beaver within Grazing Systems in Wyoming

Stream water flowing from watersheds subjected to continuous and deferred rotation grazing by livestock was sampled to enumerate bacteria for detecting differences between grazing treatments and streams. Fecal coliforms, fecal streptococci, total counts at 200 C, and bacteria capable of fluorescing under long wave radiation were selected as indicators of pollution. The study was conducted two summers, 1979 and 1980, on mountain rangeland near Laramie, Wyo. Bacteria counts for different indicator groups varied in their ability to detect change between grazing treatments as well as between streams. Fluorescing bacteria and total counts were of little value in explaining nonpoint source pollution whereas fecal coliform and streptococci were. Variation in counts of fecal coliform and streptococci could not be fully accounted for by differences in grazing management but is partially explained by beaver damming of stream flow. Given that beaver impoundment of selected stream reaches is equal, variation in nonpoint pollution may be caused by differences in grazing treatments. Recently the role of livestock grazing in causing nonpoint pollution to stream flow has received attention (Stephenson and Street 1978, Doran and Linn 1979, Jawson et al. 1982). To help differentiate best management practices for grazing livestock on native rangeland, bacterial indicators of pollution must be determined. Many researchers have observed elevated fecal coliform and fecal streptococci counts in streams draining grazed rangeland (Morrison and Fair 1966, Kunkle and Meiman 1967, Stevenson and Street 1978, Doran and Linn 1979, Jawson et al. 1982). Declining counts of these bacteria were observed in the streams in pastures after the removal of livestock (Kunkle and Meiman 1967, Skinner et al. 1974b, Milne 1976, Skovlin et al. 1977, Duff 1978, Doran and Linn 1979). Variations in fecal coliforms in streams have been partially explained by rainfall runoff (Doran and Linn 1979, Jawson et al. 1982) deferred grazing management, animal density, access to streams, as well as physical, hydrologic and biological characteristics of drainage basins (Stephenson and Street 1978). In contrast Buckhouse and Gifford (1976) were unable to detect any significant changes in bacterial contamination associated with cattle grazing on watersheds using rainfall simulation to create overland flow. Milne (1976) and Stephenson and Street (1978) have found that livestock being fed on irrigated pastures during winter have a significant effect on bacterial contamination of adjacent streams. Milne (1976) reported, however, that this high contamination was short lived and quickly declined with the cessation of grazing. Bacterial concentrations have been shown by many to vary with stream flow (Morrison and Fair 1966; Kunkle and Meiman 1967; Skinner et al. 1972, 1974b; Stevenson and Street 1978; Jawson 1982). Indicator bacteria have been found to be more numerous in sediments than overlying water (Hendricks 1971, VanDonsel and Authors are associate professor, former graduate student, and assistant professor Division of Range Management; and associate professor, Division of Microbiology and Veterinary Medicine, College of Agriculture, University of Wyoming, Box 3354, Laramie 8207 I. This study was supported by Wyoming Agricultural Experiment Station funds, WYO-153-80. Published as Journal Article 1210 of WAES. 142 Geldrich 1971, Matson et al. 1978). Disruption of sediment has been found to increase fecal coliforms in the overlying water (Grimes 1975). Stephenson and Street (1978) inferred and Stephenson and Rychert (1982) confirmed settling of organisms in sediment could explain higher counts in streams at times when livestock were not present. These studies suggest that it is important to sample both sediment and overlying water to obtain an accurate evaluation of water quality in pastured lands. In addition to sedimentation, increased numbers of indicator bacteria may result from release of cells growing in algae mats (McFeters et al. 1977). They stated that stream aspect, shade, depth, and temperature were important for sustaining algae growth which allowed growth of trapped indictor bacteria. Johnson et al. (1978) reported that suspended solids in a stream typical of those draining the front range of Colorado were higher in a nongrazed pasture than in an adjoining downstream grazed pasture. Removal of beaver dams in the nongrazed pasture was thought to be the probable cause of the increased suspended solids in the stream. Foote (1937) found little effect of beaver upon the numbers of the coli-aerogens group of bacteria in water above and below beaver ponds. However, he stated that under certain circumstances beaver could excrete large numbers of these organisms. The purpose of the present study was to monitor change in bacterial counts within streams flowing through 2 different large pasture grazing systems. Beaver activity was prevalent on streams flowing through the study region. Their possible role in explaining differences found in bacteria counts between grazing systems and streams was investigated. Null hypotheses tested include (1) there were no differences in bacterial counts between grazing systems and (2) and there were no differences in bacteria counts between streams studied.

Bacterial Quality of Recycled Wastewater Used for Flushing Holding Pens

In a study at the Clemson University LaMaster Dairy Center we examined the bacterial quality of recycled wastewater used to flush holding pens. Two 11,400-liter tanks were used, one containing recycled wastewater and another containing chlorinated city water. Each tank was used to flush a holding lot housing approximately 20 cows. Water samples were obtained from each holding tank and from three equidistant points along the flow of the flush water. Swabbings were collected at each of the three sampling points in each pen after water had drained. Each sample was cultured and enumerated for total coliforms, Escherichia coli, Enterobacter sp., Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus sp., klebsiella, pseudomonas, and salmonella. All bacteria observed were in significantly greater numbers in the holding tanks of recycled wastewater as opposed to chlorinated city water. Only Staphylococcus aureus was in greater numbers in flushed, recycled wastewater than flushed, chlorinated city water. Few differences in bacteria counts were observed on surfaces flushed with recycled wastewater and with chlorinated city water.

Composted Dairy Waste Solids and Crushed Limestone as Bedding in Free Stalls

Differences in bacteria counts of bedding, teat swabs, and milk samples of lactating Holstein dairy cows bedded on crushed limestone, freshly composted dairy waste solids, and a 50:50 mixture of dairy waste solids and limestone were observed. Free-stall pens were bedded with each type of bedding, each pen containing six randomly selected cows. Bedding, teat swab, and milk samples were taken at 7-day intervals for 28 days. Each sample was tested for the presence and enumeration of Escbericbia coli, Enterobacter, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococci. Bedding samples also were tested for pH. The limestone treatment resulted in lower bacteria counts in bedding, teat swabs, and milk than other treatments. There was no significant difference in bacterial counts between the dairy waste solids and the 50:50 mixture treatments. The pH of each bedding material appeared to affect bacterial counts.

Dairy Waste Solids as a Possible Source of Bedding

Bacteria counts are decreased in dairy waste solids by the process of composting over 14 days. Bacteria counts showed a significant increase as a result of contact with animals when composted solids were used as bedding in free stalls. Our experimental design attempted to detect a direct relationship between bacteria counts in bedding and on teats and possibly in milk. Each sample of bedding, teat swabs, and milk was enumerated for Esberichia coli, Enterobacter, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus. Clean rubber mats were a control for the composted dairy waste solids. Even though there was a significant increase in bacteria counts of dairy waste solids bedding as compared to the rubber mats, there was no significant difference in bacteria counts of teats or milk between the two types of bedding. This indicated that there was no direct relationship between microflora in bedding and microflora on teats and in milk. With adequate composting, dairy waste solids appear to be a suitable choice of bedding in free stalls.

THE NEW PLATE COUNT MEDIA IN ROUTINE PLATE COUNTS ON MILK

A number of experiments were carried out to investigate the differences in bacteria counts on milk samples when the new “milk-free” plating media were compared with the old standard TGEM medium. Variations in type of milk, raw or pasteurized; grade of milk; high or low quality, incubation temperature and laboratory technique were included in these studies. The results obtained are similar to other reported comparative studies. It is likely that over on extended period the average counts with the new media will compare favorably with the old medium.