Aerobic Colony-forming Units Research Articles

Prevalence of Small Intestinal Bacterial Overgrowth Syndrome in Patients with Non-Alcoholic Fatty Liver Disease/Non-Alcoholic Steatohepatitis: A Cross-Sectional Study.

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial, wide-spectrum liver disorder. Small intestinal bacterial overgrowth (SIBO) is characterized by an increase in the number and/or type of colonic bacteria in the upper gastrointestinal tract. SIBO, through energy salvage and induction of inflammation, may be a pathophysiological factor for NAFLD development and progression. Consecutive patients with histological, biochemical, or radiological diagnosis of any stage of NAFLD (non-alcoholic fatty liver [NAFL], non-alcoholic steatohepatitis [NASH], cirrhosis) underwent upper gastrointestinal endoscopy. Duodenal fluid (2cc) was aspirated from the 3rd-4th part of duodenum into sterile containers. SIBO was defined as ≥103 aerobic colony-forming units (CFU)/mL of duodenal aspirate and/or the presence of colonic-type bacteria. Patients without any liver disease undergoing gastroscopy due to gastroesophageal reflux disease (GERD) comprised the healthy control (HC) group. Concentrations (pg/mL) of tumor necrosis factor alpha (TNFα), interleukin (IL)-1β, and IL-6 were also measured in the duodenal fluid. The primary endpoint was to evaluate the prevalence of SIBO in NAFLD patients, while the comparison of SIBO prevalence among NAFLD patients and healthy controls was a secondary endpoint. We enrolled 125 patients (51 NAFL, 27 NASH, 17 cirrhosis, and 30 HC) aged 54 ± 11.9 years and with a weight of 88.3 ± 19.6 kg (NAFLD vs. HC 90.7 ± 19.1 vs. 80.8 ± 19.6 kg, p = 0.02). Overall, SIBO was diagnosed in 23/125 (18.4%) patients, with Gram-negative bacteria being the predominant species (19/23; 82.6%). SIBO prevalence was higher in the NAFLD cohort compared to HC (22/95; 23.2% vs. 1/30; 3.3%, p = 0.014). Patients with NASH had higher SIBO prevalence (6/27; 22.2%) compared to NAFL individuals (8/51; 15.7%), but this difference did not reach statistical significance (p = 0.11). Patients with NASH-associated cirrhosis had a higher SIBO prevalence compared to patients with NAFL (8/17; 47.1% vs. 8/51; 15.7%, p = 0.02), while SIBO prevalence between patients with NASH-associated cirrhosis and NASH was not statistically different (8/17; 47.1% vs. 6/27; 22.2%, p = 0.11). Mean concentration of TNF-α, IL-1β, and IL-6 did not differ among the different groups. The prevalence of SIBO is significantly higher in a cohort of patients with NAFLD compared to healthy controls. Moreover, SIBO is more prevalent in patients with NASH-associated cirrhosis compared to patients with NAFL.

Effectiveness of Dry Hydrogen Peroxide on Reducing Environmental Microbial Bioburden Risk in a Pediatric Intensive Care Unit

Background: Environmental contamination is a known risk factor for healthcare-associated infection acquisition. Transmission of pathogens from the environment can occur from indirect or direct patient contact with the environment or via healthcare workers’ hands. Dry hydrogen peroxide (DHP) has been shown to reduce microbial contamination in the hospital setting. This novel technology allows safe delivery of hydrogen peroxide in an occupied space, using ambient air and humidity to help create DHP. This study describes the implementation of DHP as an adjunct to routine environmental cleaning and disinfection, with the goal of reducing air and surface microbial bioburden in the intensive care unit (ICU) of a pediatric oncology hospital in Guatemala. Methods: A prospective IRB-approved study was conducted. Two rooms served as controls and 2 rooms served as intervention DHP sites. Air and surface cultures (5 high-touch, 2 low-touch) and adenosine triphosphate (ATP) swabs were collected from study areas for 1 week prior to deployment of the portable DHP units and at various time points for 1 month during the intervention phase. Air samples were collected using settling plates. The level of microbial burden was measured using colony-forming units (CFU) and ATP levels. A comparison between groups was carried out using Poisson regression analyses for CFU counts and linear regression analyses for log-transformed ATP levels. Results: In total, 280 surface cultures and ATP surface swabs were collected and analyzed. The overall mean microbial burden was significantly reduced in the intervention group compared to the control group (mean, 5.50 vs 11.77; P ≤ .0001). Reductions in microbial CFU were observed across all sampling sites in the intervention group. ATP readings in both control and intervention group showed passing levels of surface cleanliness. ATP was measured in terms of relative light units (RLU). A reduction in the mean RLU levels was also noted in the intervention group compared to the control group (172.08 vs 225.83; P ≤ .006). A reduction in aerobic CFU was seen as well in the air samples in the intervention group but was not statistically significant (P = .139). The ICU census was full, and services were not affected. Conclusions: DHP was effective in reducing surface and air microbial bioburden in an occupied space. Further studies of the impact of DHP decontamination on incidence of nosocomial infections should be performed.Funding: This study was supported by Synexis.Disclosures: None

People as a Contamination Source in Pharmaceutical Clean Rooms-Source Strengths and Calculated Concentrations of Airborne Contaminants.

Results are presented from studies performed in a test chamber on clean room garments used, laundered, and sterilized (autoclaved 20 min at 121°C), 50, 60, and 70 times, and garments used, laundered, and sterilized with a prolonged autoclave cycle 50 times. The source strength is described as the mean value of the number per second of airborne particles and aerobic colony-forming units (CFUs), respectively, emitted from one person dressed in the system to be evaluated. Results from body-box tests have been used to calculate theoretical expected concentrations of airborne aerobic CFUs and particles (≥0.5 µm) in clean rooms with different numbers of people present and at different airflows (m3/s). Theoretical expected concentrations of airborne aerobic CFUs are often below the detection level of traditional measuring equipment.

Evaluating the effects of sewage sludge compost applications on the microbial activity, the nutrient and heavy metal content of a Chernozem soil in a field survey

Sewage sludge contains organic matter and micro and macronutrients which are potentially useful for agricultural usage. However, it can be harmful when containing undesirable amounts of organic pollutants, heavy metals, or pathogens. Our study focused on examining the changes in the extractable nutrient, organic matter and heavy metal contents of a Chernozem soil and the alteration of the soil biological activity as a consequence of low-dose municipal sewage sludge compost applications (0.5 t/ha). Sampling campaigns were done in 2018 near Újkígyós (SE Hungary) during which composite soil samples (0–30 cm and 30–60 cm) and groundwater samples were collected for assessing changes in the nutrient and heavy metal concentrations as a result of compost amendments’ use. Additionally, upper soil (0–50 cm) and subsoil (50–80 cm) were sampled for assessing biological parameters, considered to be aerobic and anaerobic soil layers, respectively. Soil samples were analyzed for the basic pedological parameters (pH, organic matter, carbonates and texture), nutrients (K2O, P2O5, N-forms and organic matter) and heavy metal concentrations following standard extraction procedures. The microbial properties were characterized by colony-forming units (CFUs) and enzyme activity measurements. The results of the nutrient analyses show significantly increased soil-bound K2O, P2O5 and NO2− + NO3− contents linked to the sewage sludge treatments. However, neither the organic matter nor the heavy metal content varied significantly in the sludge-amended soil compared with a control site. The microbiological analyses revealed that the sewage sludge treatments tended to increase the aerobic CFUs, but not that of the anaerobic microbes. The average catalase enzyme activity in both the aerobic and anaerobic samples and the average dehydrogenase activity only in the aerobic layers showed a slight but not significant increase in the compost-amended soils. Overall, these results convincingly demonstrated that amending soils with low doses of municipal sewage sludge composts (lacking any industrial sources) can be a sustainable fertilizing practice taking advantage of their high N, P and K contents that are slowly converted to their bioavailable forms thus preventing their excessive leaching in the groundwater.

Comparative Antimicrobial Efficacy of Two Hand Sanitizers in Intensive Care Units Common Areas: A Randomized, Controlled Trial.

OBJECTIVE Contaminated hands of healthcare workers (HCWs) are an important source of transmission of healthcare-associated infections. Alcohol-based hand sanitizers, while effective, do not provide sustained antimicrobial activity. The objective of this study was to compare the immediate and persistent activity of 2 hand hygiene products (ethanol [61% w/v] plus chlorhexidine gluconate [CHG; 1.0% solution] and ethanol only [70% v/v]) when used in an intensive care unit (ICU). DESIGN Prospective, randomized, double-blinded, crossover study SETTING Three ICUs at a large teaching hospital PARTICIPANTS In total, 51 HCWs involved in direct patient care were enrolled in and completed the study. METHODS All HCWs were randomized 1:1 to either product. Hand prints were obtained immediately after the product was applied and again after spending 4-7 minutes in the ICU common areas prior to entering a patient room or leaving the area. The numbers of aerobic colony-forming units (CFU) were compared for the 2 groups after log transformation. Each participant tested the alternative product after a 3-day washout period. RESULTS On bare hands, use of ethanol plus CHG was associated with significantly lower recovery of aerobic CFU, both immediately after use (0.27 ± 0.05 and 0.88 ± 0.08 log10 CFU; P = .035) and after spending time in ICU common areas (1.81 ± 0.07 and 2.17 ± 0.05 log10 CFU; P<.0001). Both the antiseptics were well tolerated by HCWs. CONCLUSIONS In comparison to the ethanol-only product, the ethanol plus CHG sanitizer was associated with significantly lower aerobic bacterial counts on hands of HCWs, both immediately after use and after spending time in ICU common areas. CLINICAL TRIAL IDENTIFIER Clinicaltrials.gov identifier NCT02258412 Infect Control Hosp Epidemiol 2018;39:267-271.

Vertical and horizontal distributions of microbial abundances and enzymatic activities in propylene-glycol-affected soils

The natural microbial activity in the unsaturated soil is vital for protecting groundwater in areas where high loads of biodegradable contaminants are supplied to the surface, which usually is the case for airports using aircraft de-icing fluids (ADF) in the cold season. Horizontal and vertical distributions of microbial abundance were assessed along the western runway of Oslo Airport (Gardermoen, Norway) to monitor the effect of ADF dispersion with special reference to the component with the highest chemical oxygen demand (COD), propylene glycol (PG). Microbial abundance was evaluated by several biondicators: colony-forming units (CFU) of some physiological groups (aerobic and anaerobic heterotrophs and microscopic fungi), most probable numbers (MPN) of PG degraders, selected catabolic enzymatic activities (fluorescein diacetate (FDA) hydrolase, dehydrogenase, and β-glucosidase). High correlations were found between the enzymatic activities and microbial counts in vertical soil profiles. All microbial abundance indicators showed a steep drop in the first meter of soil depth. The vertical distribution of microbial abundance can be correlated by a decreasing exponential function of depth. The horizontal trend of microbial abundance (evaluated as total aerobic CFU, MPN of PG-degraders, and FDA hydrolase activity) assessed in the surface soil at an increasing distance from the runway is correlated negatively with the PG and COD loads, suggesting the relevance of other chemicals in the modulation of microbial growth. The possible role of potassium formate, component of runway de-icers, has been tested in the laboratory by using mixed cultures of Pseudomonas spp., obtained by enrichment with a selective PG medium from soil samples taken at the most contaminated area near the runway. The inhibitory effect of formate on the growth of PG degraders is proven by the reduction of biomass yield on PG in the presence of formate.

Effect of chlorhexidine, povidone iodine, and ozone on microorganisms in dental aerosols: randomized double-blind clinical trial.

Dental handpieces, ultrasonic scalers, air polishers, air abrasion units produce the most visible aerosols. The objective of this study was to assess the effect of chlorhexidine (CHX), povidone iodine (PI), and ozone (OZ) on the microorganisms in dental aerosols. A total of 60 patients were included in this study, they were randomly assigned into three groups and were subjected to scaling before and after rinsing with 0.2% CHX, 1% PI or irrigation with OZ. Blood agar plates were used to collect the gravitometric settling of aerosols and were sent for aerobic and anaerobic culture. The results demonstrated high percentage reduction of aerobic and anaerobic colony forming units (CFUs) in all three groups. In aerobic CFUs, CHX showed the highest reduction (57%) at mask position whereas at chest position and at 9 ft, PI showed higher CFU reductions (37% and 47%, respectively). In anaerobic CFUs, CHX showed the highest percentage of reduction at chest level (43%) and at 9 ft (44%). CHX, PI and OZ showed similar effects in reducing aerobic and anaerobic CFU's at the chest mask and at 9 ft. OZ can be used as a preprocedural agent, considering its beneficial effects.

Viability, diversity and composition of the bacterial community in a high Arctic permafrost soil from Spitsbergen, Northern Norway

The viable and non-viable fractions of the bacterial community in a 2347-year-old permafrost soil from Spitsbergen were subjected to a comprehensive investigation using culture-independent and culture-dependent methods. LIVE/DEAD BacLight staining revealed that 26% of the total number of bacterial cells were viable. Quantitatively, aerobic microcolonies, aerobic colony-forming units and culturable anaerobic bacteria comprised a minor fraction of the total number of viable bacteria, which underlines the necessity for alternative cultivation approaches in bacterial cryobiology. Sulfate reduction was detected at temperatures between -2 degrees C and 29 degrees C while methanogenesis was not detected. Bacterial diversity was high with 162 operational taxonomic units observed from 800 16S rDNA clone sequences. The 158 pure cultures isolated from the permafrost soil affiliated with 29 different bacterial genera, the majority of which have not previously been isolated from permafrost habitats. Most of the strains isolated were affiliated to the genera Cellulomonas and Arthrobacter and several of the pure cultures were closely related to bacteria reported from other cryohabitats. Characterization of viable bacterial communities in permafrost soils is important as it will enable identification of functionally important groups together with the as yet undescribed adaptations that bacteria have evolved for surviving subzero temperatures for millennia.

Effect of Addition of Hydrated Lime to Litter on Recovery of Selected Bacteria and Poult Performance

Recently, we demonstrated that 10 or 20% (wt/vol) hydrated lime used in poultry litter significantly reduced Salmonella enteritidis survival in vitro. However, preliminary studies with day-of-hatch poults suggested that lime in excess of 5% (wt/vol) in new litter caused mild but apparent ocular and respiratory irritation and thus was not further evaluated. Presently, we evaluated the effect of lower concentrations of hydrated lime in new dry pine wood shavings (0, 0.2, 1, or 5% wt/vol) on recovery of Salmonella, Campylobacter, coliforms, total aerobic colony-forming units, and poult performance (hatch to 7 wk). Although lime did not affect body weight at 3 wk of age, at 7 wk of age turkeys from 0.2% lime-treated pens were significantly (P < 0.05) heavier (219 g/bird) than turkeys grown in control pens. Even though incorporation of lime at the selected concentrations did not reduce Campylobacter or Salmonella recovery, lime did reduce overall aerobic colony-forming units and significantly increased weight gain in this experiment, possibly through reduction of other low level pathogens not measured in this study.

Use of Petrifilm™ to Evaluate the Microflora of Frozen Dessert Mixes

Ninety vanilla frozen dessert mix samples were analyzed to determine total microbial populations and coliforms present in samples inoculated with a coliform isolated from raw milk. Standard methods agar (SMA, PCA, Difco) and violet red bile agar (VRBA, Difco) as well as Petrifilm™ (PSM, PVRB) were used for plating of samples. Standard VRBA 1:10 method produced significantly higher counts of colony-forming units (CFU) than PVRB 2:3 and VRBA 2:3 methods. VRBA 2:3 colony-forming unit counts were also significantly higher than those on PVRB 2:3, but both methods showed a moderately strong linear relationship. Repeatabilities of all three coliform plating methods (VRBA 1:10, VRBA 2:3, and PVRB 2:3) were acceptably low. Less than 10% of samples plated on SMA and PSM resulted in total aerobic colony-forming units in the countable range, making evaluation of data difficult and resulting in a lack of strong linear relationship between PSM and SMA. An additional 70 local retail store samples containing naturally occurring coliforms were evaluated using PVRB 2:3 and VRBA 1:10 methodology, confirmed in brilliant green lactose bile broth (BGLB, Difco) and compared to standard VRBA 1:10 previously analyzed. All methods were equivalent for mean log coliforms, i.e., 1.38,1.33, and 1.31 for PVRB 2:3, VRBA 2:3, and VRBA 1:10, respectively. Petrifilm™ methods were comparable to standard methods for enumerating coliforms in frozen dairy products, and would be a valid alternative to standard coliform and total plate count methods.

Bacteriological quality of broiler carcasses as affected by in-plant lactic acid decontamination

In an attempt to improve the bacteriological quality of broiler carcasses the bactericidal effect of treatments with 1% and 2% lactic acid was investigated. Bacterial colonisation was determined immediately after treatment, after the carcasses had been chilled and during storage at 0°C. Examination included numbers of mesophilic aerobic and psychrotrophic aerobic colony-forming units (CFU), CFU of Enterobacteriaceae at 37°C and CFU of Staphylococcus aureus. Immediately after treatment colonisation per gram skin was generally reduced by about 1 log. Initially 2% lactic acid was not found significantly more effective in reducing colony counts than 1%. However, treatment with 2% lactic acid suppressed post-decontamination colonisation with Enterobacteriaceae more effectively than 1% lactic acid, as determined after 15–18 days storage at about 0°C. Lactic acid treatment was most effective when applied shortly before chilling. Successive treatment at three different stages during slaughtering did not increase reduction of colony counts. It is concluded that decontamination with 1–2% lactic acid at pH 2, when applied shortly before chilling, will markedly improve the bacterial safety and increase the refrigerated shelf life of broiler carcasses.

Comparison of a Dry Medium Culture Plate (Petrifilm SM Plates) Method to the Aerobic Plate Count Method for Enumeration of Mesophilic Aerobic Colony-Forming Units in Fresh Ground Beef

Mesophilic aerobic microbial populations in fresh ground beef were enumerated with a new system, Petrifilm™ SM Plates (PSM), and with the conventional aerobic plate count (APC) method using standard methods agar (SMA). Total colony-forming units were determined in 119 fresh ground beef samples (29 extra-lean, 30 lean and 60 regular) purchased at nine different retail markets over a period of 6 wk. Linear regression analysis of PSM vs. APC counts gave a slope of 0.963, an intercept of −0.027, and a correlation coefficient of 0.951. Mean log10 counts on PSM were 5.86 compared to 6.11 on SMA (P<0.01) or a mean log10 difference of −0.25. These analyses indicate that the Petrifilm SM method would be a possible alternative for the aerobic plate count method.