Antimicrobial resistance in pathogenic aerobic bacteria causing surgical site infections in Mbarara regional referral hospital, Southwestern Uganda.

Surgical site infections (SSI) remain a common postoperative complication despite use of prophylactic antibiotics and other preventive measures, mainly due to increasing antimicrobial resistance. Here, we present antimicrobial resistance rate of bacteria isolated in clinical cases of SSI. A hospital based descriptive cross sectional study was conducted on 83 consented postoperative patients with clinical SSI. Data on patients was obtained using structured data collection form. Two swabs were collected aseptically from each patient. Bacteriological culture examination and identification was done following standard microbiological techniques. Antibiotic susceptibility test was done by Kirby-Bauer disc diffusion method. Gram negative bacteria (GNB) were predominant (65.59%) with the dominant being Klebsiella species (29.03%). Overall 86% of aerobic bacteria isolated were multidrug resistant (MDR) where 65.63% and 96.72% of Gram positive and Gram negative isolates were MDR respectively. All the isolates with exception of Enterococci species were resistant to ampicillin. GNB showed high resistance to ceftriaxone, sulfamethoxazole/trimethoprim and gentamicin. All the isolated Klebsiella spp were MDR. S. aureus were all resistant to oxacillin. The isolation rate was higher in emergency, males and dirty wounds in relation to nature of surgery, gender and class of surgical wound respectively. These findings necessitate judicious antibiotic use and calls for surveillance of SSIs periodically as well as strict adherence to good sanitation practice to reduce spread of drug-resistant pathogens.

Prospective, randomised clinical trial of four different presurgical hand antiseptic techniques in equine surgery.

BACKGROUND: Currently, the World Health Organization recommends the use of alcohol-based hand rubs (ABR) for surgical hand preparation in human surgery. When disinfecting soaps are used, a rubbing technique causes less skin irritation than brush scrubbing. Based on a recent survey, most equine surgeons still use disinfecting soap. The efficacy of scrubbing vs. rubbing and the use of sole ABR compared with chlorhexidine (CHx)- based products has not been evaluated in the equine surgical setting. OBJECTIVES: To compare four surgical hand antisepsis techniques in equine surgery for reduction of aerobic bacterial counts from pre- to post-preparation (immediate efficacy) and at the end of surgery (sustained efficacy). STUDY DESIGN: Randomised, prospective clinical trial. METHODS: A 4% CHx-based product applied with either a scrub or rub technique, one sole ABR (ET; 80% ethanol) and one CHx/alcohol-combination (CHx/ET; 1% CHx and 61% ethanol) product both applied with a rub technique were evaluated. Samples were collected by glove juice technique and cultured on 3M™ Petrifilm plates and counted using a 3M™ Petrifilm plate reader. RESULTS: Immediate mean bacterial log10 colony forming unit (CFU) reduction was 2.4 for CHx-scrub, 2.8 for CHx-rub, 3.1 for CHx/ET and 2.1 for ET. CHx/ET resulted in significantly lower bacterial counts than CHx-scrub (P<0.005) and ET (P<0.001) while CHx-rub resulted in significantly lower counts than ET (P<0.001). At the end of surgery bacterial counts were the lowest for CHx-rub, significantly lower than CHx/ET (P<0.001) and ET (P<0.001). There was no difference between CHx-rub and -scrub techniques (P = 0.7). MAIN LIMITATIONS: Bacterial counts were used as the outcome measure rather than prevalence of surgical site infection, and the effect of hand preparation on skin health was not assessed. CONCLUSIONS: ABR did not decrease bacterial log10 CFU counts more effectively than CHx products. When using CHx soaps in the equine setting, hand-rub is as effective as a hand-scrub-technique.

A clinical trial comparing antimicrobial efficacy of "essential oil of Ocimum sanctum" with triple antibiotic paste as an intracanal medicament in primary molars.

OBJECTIVES: To evaluate the aerobic and anaerobic antimicrobial efficacy of Ocimum Sanctum (Tulsi) essential oil and compare it with that of triple antibiotic paste (TAP) by collecting microbiological samples from the root canals of primary molars. STUDY DESIGN: Forty children were selected for the study and were randomly divided into two groups of twenty each, namely, TAP group and O. sanctum group (basil). Six intracanal samples were collected for every patient, comprising of two each after access opening, irrigation and after 3 days of intracanal medicament placement. These samples were cultured in aerobic and anaerobic environment and later colony-forming units (CFUs) were counted and intragroup as well as intergroup comparison was done. RESULTS: Analysis of the results showed that there was a statistically significant reduction in CFUs after using essential oil of O. sanctum as an intracanal medicament. Saline use also leads to a statistically significant reduction in CFUs irrespective of the intracanal medicament used. TAP showed better antibiotic properties in comparison with that of O. sanctum. CONCLUSION: Antibiotic use is often associated with the adverse effects and development of resistance due to injudicious use. O. sanctum can be used in cases of long-standing infection owing to its antimicrobial efficacy and anti-inflammatory potential as an intracanal medicament in primary teeth.

Enhancement mechanisms of short-time aerobic digestion for waste activated sludge in the presence of cocoamidopropyl betaine.

Cocoamidopropyl betaine (CAPB), which is a biodegradable ampholytic surfactant, has recently been found to dramatically enhance the aerobic digestion of waste activated sludge (WAS) in short-time aerobic digestion (STAD) systems. Therefore, it is important to understand the mechanisms in which CAPB enhances WAS aerobic digestion performance. Results showed that CAPB could dramatically enhance the solubilization of soluble proteins (PN), polysaccharides (PS), nucleic acids (NA) and humic-like substances (HS) in the STAD system within the initial 2 h. Then PN, PS and NA gradually decreased, while HS showed only minor decease. In addition, CAPB increased the proportion of low MW fractions (<20 kDa) from 4.22% to 39.4%, which are more biodegradable. Specific oxygen uptake rates and dehydrogenase enzyme activity results indicated that CAPB markedly improved the aerobic microorganism activities. Microbial community analyses and principle coordinate analyses (PCoA) revealed that CAPB increased the proportion of some functional microorganisms, including Proteobacteria, Planctomycetales, Acinetobacter, Pseudomonas and Aeromonas. The changes driven by CAPB could explain the enhanced performance of the STAD system for WAS aerobic treatment.

Novel long-chain compounds with both immunomodulatory and MenA inhibitory activities against Staphylococcus aureus and its biofilm.

Menaquinone (MK) biosynthesis pathway is a potential target for evaluating antimicrobials in gram-positive bacteria. Here, 1,4-dihydroxy-2-naphthoate prenyltransferase (MenA) was targeted to reduce methicillin-resistant Staphylococcus aureus (MRSA) growth. MenA inhibiting, long chain-based compounds were designed, synthesized and evaluated against MRSA and menaquinone utilizing bacteria in aerobic conditions. The results showed that these bacteria were susceptible to most of the compounds. Menaquinone (MK-4) supplementation rescued MRSA growth, suggesting these compounds inhibit MK biosynthesis. 3a and 7c exhibited promising inhibitory activities with MICs ranging 1-8 µg/mL against MRSA strains. The compounds did not facilitate small colony variant formation. These compounds also inhibited the biofilm growth by MRSA at high concentration. Compounds 3a, 6b and 7c displayed a promising extracellular bactericidal activity against MRSA at concentrations equal to and four-fold less than their respective MICs. We also observed cytokines released from THP-1 macrophages treated with compounds 3a, 6b and 7c and found decreases in TNF-α and IL-6 release and increase in IL-1ß. These data provide evidence that MenA inhibitors act as TNF-α and IL-6 inhibitors, raising the potential for development and application of these compounds as potential immunomodulatory agents.

In vivo and in vitro effects of selected antioxidants on rabbit meat microbiota.

The purpose of this study was to investigate the effect of dietary vitamin E or EconomasE™ supplementation on the growth of several background/pathogenic bacteria on rabbit carcasses and hamburgers during refrigerated storage. For 51days, 270 New Zealand rabbits received either a basal diet, or experimental diets enriched with 100 or 200mg/kg of vitamin E or EconomasE™. The bacteria studied were Salmonella, Listeria monocytogenes, Pseudomonas, Enterobacteriaceae, Escherichia coli, coagulase-positive staphylococci, plus both mesophilic and psychrotrophic aerobes. The growth of Listeria monocytogenes on contaminated patties was evaluated through a challenge test. The potential protective or antimicrobial effect of vitamin E or EconomasE™ on Listeria monocytogenes or Pseudomonas aeruginosa was assessed in vitro. Diet did not influence the concentrations of bacteria found on rabbit carcasses and developing on hamburgers. Vitamin E (in vivo and in vitro) and EconomasE™ in vivo had a protective antioxidant role, while EconomasE™ in vitro had strong antibacterial activity against Listeria monocytogenes, but not against Pseudomonas aeruginosa.

Effects of 3,5-dichlorophenol on excess biomass reduction and bacterial community dynamics in activated sludge as revealed by a polyphasic approach.

The effects of 3,5-dichlorophenol (DCP) on excess sludge reduction and microbial community dynamics were studied using laboratory-scale activated sludge reactors. The addition of 3,5-DCP at an interval of 7-8 days of operation resulted in effective reduction of growing biomass without a significant decrease in substrate removal activity. However, this uncoupling effect completely disappeared after 30 days of operation. Quinone profiling showed that a drastic component shift from ubiquinone-8 (Q-8) to Q-10 as the major homolog took place during this period of operation, suggesting that Q-10-containing bacteria, i.e., Alphaproteobacteria, became predominant at the uncoupler-ineffective stage. This result was supported by PCR-aided denaturating gradient gel electrophoresis and clone library analyses of 16S rRNA genes and fluorescence in situ hybridization. Among the gene clones detected, those corresponding to Brevundimonas predominated at the uncoupler-ineffective stage. The uncoupler-added reactor yielded 3,5-DCP-resistant Pseudomonas strains as the predominant cultivable bacteria and non-3,5-DCP-resistant Brevundimonas strains as the second most abundant isolates These results suggest that the disappearance of the uncoupling function of 3,5-DCP during the long-term operation of the reactor is related to the drastic community change with increasing populations of Alphaproteobacteria. Most of these alphaproteobacteria represented by Brevundimonas are not resistant to 3,5-DCP but, by an unknown mechanism, may support the bioprotection of the microbial community from the uncoupling effect.

Reduced bacterial colony count of anaerobic bacteria is associated with a worsening in lung clearance index and inflammation in cystic fibrosis.

Anaerobic bacteria have been identified in abundance in the airways of cystic fibrosis (CF) subjects. The impact their presence and abundance has on lung function and inflammation is unclear. The aim of this study was to investigate the relationship between the colony count of aerobic and anaerobic bacteria, lung clearance index (LCI), spirometry and C-Reactive Protein (CRP) in patients with CF. Sputum and blood were collected from CF patients at a single cross-sectional visit when clinically stable. Community composition and bacterial colony counts were analysed using extended aerobic and anaerobic culture. Patients completed spirometry and a multiple breath washout (MBW) test to obtain LCI. An inverse correlation between colony count of aerobic bacteria (n = 41, r = -0.35; p = 0.02), anaerobic bacteria (n = 41, r = -0.44, p = 0.004) and LCI was observed. There was an inverse correlation between colony count of anaerobic bacteria and CRP (n = 25, r = -0.44, p = 0.03) only. The results of this study demonstrate that a lower colony count of aerobic and anaerobic bacteria correlated with a worse LCI. A lower colony count of anaerobic bacteria also correlated with higher CRP levels. These results indicate that lower abundance of aerobic and anaerobic bacteria may reflect microbiota disruption and disease progression in the CF lung.

The aerobic activity of metronidazole against anaerobic bacteria.

Recently, the aerobic growth of strictly anaerobic bacteria was demonstrated using antioxidants. Metronidazole is frequently used to treat infections caused by anaerobic bacteria; however, to date its antibacterial activity was only tested in anaerobic conditions. Here we aerobically tested using antioxidants the in vitro activities of metronidazole, gentamicin, doxycycline and imipenem against 10 common anaerobic and aerobic bacteria. In vitro susceptibility testing was performed by the disk diffusion method, and minimum inhibitory concentrations (MICs) were determined by Etest. Aerobic culture of the bacteria was performed at 37°C using Schaedler agar medium supplemented with 1mg/mL ascorbic acid and 0.1mg/mL glutathione; the pH was adjusted to 7.2 by 10M KOH. Growth of anaerobic bacteria cultured aerobically using antioxidants was inhibited by metronidazole after 72h of incubation at 37°C, with a mean inhibition diameter of 37.76mm and an MIC of 1µg/mL; however, strains remained non-sensitive to gentamicin. No growth inhibition of aerobic bacteria was observed after 24h of incubation at 37°C with metronidazole; however, inhibition was observed with doxycycline and imipenem used as controls. These results indicate that bacterial sensitivity to metronidazole is not related to the oxygen tension but is a result of the sensitivity of the micro-organism. In future, both culture and antibiotic susceptibility testing of strictly anaerobic bacteria will be performed in an aerobic atmosphere using antioxidants in clinical microbiology laboratories.

Susceptibility and tolerance of human gut culturable aerobic microbiota to wine polyphenols.

Diet is one of the main factors that could affect quantitatively and qualitatively the stability of the gut microbiota. Polyphenols are abundantly present in the human diet and have an antimicrobial effect inducing selective changes in the microbiota composition, with potential beneficial effects for the human health. Our aim was to determine the human gut microbiota susceptibility toward wine polyphenols. Susceptibility to two commercial wine phenolic extracts (Vitaflavan(®) and Provinols™) was determined in isolates from fecal samples from 36 gastrointestinal healthy volunteers. To select the polyphenol-resistant isolates, feces were seeded in plates containing 1 mg/ml of phenolic extract. The minimal inhibitory concentration to polyphenols in the collected isolates was assessed by the agar dilution method. Overall results showed that Gram-negative isolates are most tolerant to the presence of both grape seed and red wine extracts. Furthermore, we purified to homogeneity the phenolic fractions by high-performance liquid chromatography (HPLC) to determine their antimicrobial effect and their influence on bacterial growth in four selected ATCC strains using the BioScreen apparatus. Results showed that the antimicrobial activity of the wine polyphenols is the result of the interaction of both the flavan-3-ol type and the bacteria. Bacterial Intraspecies differences in the phenolic susceptibility suggest the existence of polyphenol-resistant mechanisms that are uncharacterized as yet.

Curcumin as a potential non-steroidal contraceptive with spermicidal and microbicidal properties.

OBJECTIVE: Curcumin, a component of the curry powder turmeric, has immense biological properties, including anticancer effects. The objective of this study was to determine if curcumin can provide a novel non-steroidal contraceptive having both spermicidal and microbicidal properties. STUDY DESIGN: The effect of curcumin, with and without photosensitization, was examined on human sperm forward motility and growth of several aerobic (n=8) and anaerobic bacteria (n=4) and yeast (n=7) strains implicated in vaginosis, vaginitis, and vaginal infections in women. The effect of various concentrations of curcumin on human sperm and microbes (aerobic and anaerobic bacteria and yeast) was tested. The effect on sperm was examined by counting the sperm forward motility, and on microbes by agar and broth dilutions and colony counting. Each experiment was repeated using different semen specimens, and bacteria and yeast stocks. RESULTS: Curcumin caused a concentration-dependent inhibition of sperm forward motility with a total block at ≥250µM concentration. After photosensitization, the effective concentration to completely block sperm forward motility decreased 25-fold, now requiring only 10µM concentration for total inhibition. Curcumin concentrations between 100 and 500µM completely blocked the growth of all the bacteria and yeast strains tested. After photosensitization, the effective concentration to completely inhibit microbial growth decreased 10-fold for aerobic bacteria and yeast, and 5-fold for anaerobic bacteria. CONCLUSIONS: These findings suggest that curcumin can block sperm function and bacteria/yeast growth. It can potentially provide an ideal non-steroidal contraceptive having both spermicidal and microbicidal properties against vaginal infections.

Topical treatment with probiotic Lactobacillus brevis CD2 inhibits experimental periodontal inflammation and bone loss.

BACKGROUND AND OBJECTIVE: An increasing body of evidence suggests that the use of probiotic bacteria is a promising intervention approach for the treatment of inflammatory diseases with a polymicrobial etiology. The objective of this study was to determine whether Lactobacillus brevis CD2 could inhibit periodontal inflammation and bone loss in experimental periodontitis. MATERIAL AND METHODS: Periodontitis was induced by placing a silk ligature around the second maxillary molar of mice treated with L. brevis CD2 (8 × 10(5)  CFU in 1 mm(2) lyopatch) or placebo, which were placed between the gingiva and the buccal mucosa near the ligated teeth. The mice were killed after 5 d and bone loss was measured morphometrically, gingival expression of proinflammatory cytokines was determined by quantitative real-time polymerase chain reaction, and CFU counts of periodontitis-associated bacteria were determined after aerobic and anaerobic culture. To determine the role of arginine deiminase released by L. brevis CD2, soluble extracts with or without formamidine (arginine deiminase inhibitor) were tested in in vitro cellular activation assays. RESULTS: Mice topically treated with L. brevis CD2 displayed significantly decreased bone loss and lower expression of tumor necrosis factor, and interleukin-1ß, -6 and -17A as compared to placebo-treated mice. Moreover, L. brevis CD2-treated mice displayed lower counts of anaerobic bacteria but higher counts of aerobic bacteria than placebo-treated mice. In in vitro assays, the anti-inflammatory effects of soluble L. brevis CD2 extracts were heavily dependent on the presence of functional arginine deiminase, an enzyme that can inhibit nitric oxide synthesis. CONCLUSION: These data provide proof-of-concept that the probiotic L. brevis CD2 can inhibit periodontitis through modulatory effects on the host response and the periodontal microbiota.

[Antibacterial therapy in surgery of patients with acute destructive appendicitis].

Character of microflora of exsudate of abdominals and mucosis microflora of vermicular appendix is studied for patients with the destructive forms of appendicitis with the purpose of development of variants of antibacterial therapy at surgical treatment of patients with acute appendicitis. The patients with the destructive forms of appendicitis, which were on treatment in a municipal clinical hospital N 4 Kyiv for period 2004-2010. An Inflammatory-destructive process in an appendix is conditioned by both aerobic (Escherichia coli - 46,6 %, Enterobacter - 4,2 %, Citrobacter - 4,2 %, Klebsiella - 3,3 %, Pseudomonas aeruginosa - 5,8 %, Staphylococcus - 4,2 %) and anaerobic microorganisms (Bacteroides - 100 %) and increase Candida - 17,5 %. Antibacterial therapy is effective at 46,7 % patients with acute appendicitis. At 49,6 % patients acute appendicitis develops on a background dysbiotic intestinal disturbances. Clinically the effective charts of empiric antibacterial monotherapy 6 days it is been: Moxifloxacini intravenously 400 mgs one time in twenty-four hours during, Ertapenemi for a 1 g one time in twenty-four hours intravenously and combined - Aztreonami for a 1 g twice in twenty-four hours and of Clindamycini for 600 mgs twice in twenty-four hours, intramuscular during; Cefepimumi for a 1 g twice in twenty-four hours and of Clindamycini for 600 mgs twice in twenty-four hours, intramuscular.

The antimicrobial effect of Iseganan HCl oral solution in patients receiving stomatotoxic chemotherapy: analysis from a multicenter, double-blind, placebo-controlled, randomized, phase III clinical trial.

BACKGROUND: Cytotoxic chemotherapy induces changes in the oral microflora that may cause oral and systemic infections in myelosuppressed cancer patients. These complications prompted us to assess the antimicrobial activity of a topical Iseganan HCl mouthwash vs. placebo on the aerobic and facultatively anaerobic oral flora in these patients. METHODS: Two hundred and twenty-five chemotherapy patients were recruited into a randomized, double-blind, placebo-controlled trial, conducted at multiple centers. The study compared the antimicrobial efficacy of Iseganan HCl vs. placebo (95% of the Iseganan and 97% of the control group received myeloablative chemotherapy). Iseganan HCl 9 mg/3 ml was administered as a swish and swallow solution, six times daily for 21-28 days. Microbial cultures were made before and after the daily Iseganan mouth rinse on the first and final days of chemotherapy. RESULTS: The reduction in total microbial load after the first day of treatment was statistically significant (1.59 vs. 0.18 log10 CFU for the Iseganan HCl and placebo groups, respectively, P < 0.0001). Iseganan HCl rinse had a cumulative effect demonstrated by the significant difference between the two groups on the last day of the study (i.e. completion of Iseganan daily treatment) (P < 0.05). The reduction was mainly due to decreased densities of viridans streptococci, non-hemolytic streptococci, and yeasts. The minimal inhibitory concentration (MIC) of Iseganan HCl remained the same throughout the course of treatment. CONCLUSIONS: Topical Iseganan HCl significantly reduces the total oral aerobic bacterial, streptococcal, and yeast load. Its potential as an oral antimicrobial agent in preventing these types of infections is clear.

Synergistic effect between clove oil and its major compounds and antibiotics against oral bacteria.

BACKGROUND: Essential oils have been found to be antibacterial, antifungal, spasmolytic, and antiplasmodial activity and therapeutic effect in cancer treatment. OBJECTIVE AND DESIGN: In this study, clove oil and its major compounds, eugenol and ß-caryophyllene were evaluated against oral bacteria, either alone or in combination with ampicillin or gentamicin, via checkerboard and time kill assay. RESULTS: The antibacterial activity of the clove oil was higher than ß-caryophyllene but was similar to eugenol against all tested oral bacteria. Furthermore, the MIC and MBC were reduced to one half-one sixteenth as a result of the combination of clove oil or eugenol with antibiotics. The synergistic interaction was verified by time kill studies using the clove oil or eugenol with antibiotics. 60 min of treatment with MIC of the clove oil or eugenol with ampicillin or gentamicin resulted in an increase in the rate of killing in units of CFU/mL to a greater degree than was observed with alone. CONCLUSION: The results suggest that the clove oil and eugenol could be employed as a natural antibacterial agent against cariogenic and periodontopathogenic bacteria.

Use of culture and molecular analysis to determine the effect of antibiotic treatment on microbial community diversity and abundance during exacerbation in patients with cystic fibrosis.

BACKGROUND: Anaerobic bacteria are increasingly regarded as important in cystic fibrosis (CF) pulmonary infection. The aim of this study was to determine the effect of antibiotic treatment on aerobic and anaerobic microbial community diversity and abundance during exacerbations in patients with CF. METHODS: Sputum was collected at the start and completion of antibiotic treatment of exacerbations and when clinically stable. Bacteria were quantified and identified following culture, and community composition was also examined using culture-independent methods. RESULTS: Pseudomonas aeruginosa or Burkholderia cepacia complex were detected by culture in 24/26 samples at the start of treatment, 22/26 samples at completion of treatment and 11/13 stable samples. Anaerobic bacteria were detected in all start of treatment and stable samples and in 23/26 completion of treatment samples. Molecular analysis showed greater bacterial diversity within sputum samples than was detected by culture; there was reasonably good agreement between the methods for the presence or absence of aerobic bacteria such as P aeruginosa (κ=0.74) and B cepacia complex (κ=0.92), but agreement was poorer for anaerobes. Both methods showed that the composition of the bacterial community varied between patients but remained relatively stable in most individuals despite treatment. Bacterial abundance decreased transiently following treatment, with this effect more evident for aerobes (median decrease in total viable count 2.3×10(7) cfu/g, p=0.005) than for anaerobes (median decrease in total viable count 3×10(6) cfu/g, p=0.046). CONCLUSION: Antibiotic treatment targeted against aerobes had a minimal effect on abundance of anaerobes and community composition, with both culture and molecular detection methods required for comprehensive characterisation of the microbial community in the CF lung. Further studies are required to determine the clinical significance of and optimal treatment for these newly identified bacteria.

Antimicrobial resistance of aerobes and facultative anaerobes isolated from the oral cavity

OBJECTIVES: This study evaluated the resistance to antimicrobials of aerobes and facultative anaerobes isolated from patients wearing complete dentures, patients with gingivitis and periodontitis, and periodontally health subjects. MATERIAL AND METHODS: Three hundred and four isolates were tested. The minimal inhibitory concentrations of the drugs were evaluated through the agar dilution method using Mueller-Hinton agar. RESULTS: The most active antimicrobial drugs were the carbapenems (meropenem and imipenem), and resistance to these drugs was restrict to 1.6-2.3 percent of the isolates, as well as ciprofloxacin and rifampin. Microbial resistance to ampicillin, amoxicillin/clavulanic acid, cefoxitin, cephalothin, amikacin, chloramphenicol and nalidixic acid was particularly high. In most cases, the resistance to β-lactams was mediated by the production of hydrolytic enzymes, especially in gram-negative enteric rods, while enterococci did not evidence production of these enzymes. The association amoxicillin/clavulanic acid was not effective in 28.3 percent of the tested isolates. CONCLUSIONS: The results of this investigation confirmed that the oral cavity of patients with periodontitis and gingivitis, and particularly edentulous patients wearing complete dentures could harbor microorganisms with several antimicrobial resistance markers, and these microorganisms are frequently implicated in multiresistant, systemic, oral or nosocomial infections.

Lack of cytotoxicity by Trustwater Ecasol™ used to maintain good quality dental unit waterline output water in keratinocyte monolayer and reconstituted human oral epithelial tissue models.

UNLABELLED: We previously showed that residual treatment of dental chair unit (DCU) supply water using the electrochemically-activated solution Trustwater Ecasol™ (2.5 ppm) provided an effective long-term solution to the problem of dental unit waterline (DUWL) biofilm resulting in DUWL output water quality consistently superior to potable water. OBJECTIVES: To investigate the cytoxicity of Ecasol using cultured keratinocyte monolayers and reconstituted human oral epithelial (RHE) tissue and to extend the study of Ecasol's effectiveness in maintaining the microbiological quality of DUWL output water. METHODS: TR146 human keratinocyte monolayers and RHE tissues were exposed to Ecasol (2.5-100 ppm) for 1h periods after removal of growth medium and washing with phosphate-buffered saline (PBS). Experiments were repeated using Ecasol that had been exposed for 30 min to 1-2mg/mL bovine serum albumin (BSA), equivalent to protein concentrations in saliva. To quantitatively determine cytotoxic effects on monolayers following Ecasol exposure, the Alamar Blue proliferation assay (assesses cell viability) and the Trypan Blue exclusion assay (assesses plasma membrane integrity), were used. Cytotoxicity effects on RHE tissues were assessed by the Alamar Blue assay and by histopathology. RESULTS: Ecasol at >5.0 ppm resulted in significant (P<0.001) cytotoxicity to keratinocyte monolayers following a 1h exposure. These effects, however, were completely negated by BSA pretreatment of Ecasol. No cytotoxicity was observed in the more complex RHE tissue at any of the Ecasol concentrations tested. In a 60-week study of 10 DCUs, tested weekly, the average density of aerobic heterotrophic bacteria in Ecasol-treated (2.5 ppm) DCU supply water was <1cfu/mL and in DUWL output water was 6.5cfu/mL. CONCLUSIONS: Ecasol present as a residual disinfectant in DUWL output water is very unlikely to have adverse effects on human oral tissues at levels effective in maintaining DUWL output water quality at better than potable standard water quality.

Prevalence of fecal carriage of antibiotic-resistant bacteria in patients with acute surgical abdominal infections.

OBJECTIVE: Antibiotic resistance is increasing worldwide. The aims of the current study were to determine the fecal carriage of antibiotic-resistant bacteria and antibiotic treatment in surgical patients admitted to hospital due to acute intra-abdominal infections. MATERIALS AND METHODS: Eight Swedish surgical units participated in this prospective multicenter investigation. Rectal swabs were obtained on admission to hospital. Cultures were performed on chromogenic agar and antibiotic susceptibility testing was performed using the disk diffusion method. Extended-spectrum beta-lactamase (ESBL)-phenotype was confirmed by Etest. RESULTS: Rectal samples were obtained and analyzed from 208 patients with intra-abdominal surgical infections. Surgery was performed in 134 patients (65%). Cephalosporins were the most frequently used empirical antibiotic therapy. The highest rates of resistance among Enterobacteriaceae were detected for ampicillin (54%), tetracycline (26%), cefuroxime (26%) and trimethoprim-sulfamethoxazole (20%). The prevalence of decreased susceptibility (I + R) for the other antibiotics tested was for ciprofloxacin 20%, piperacillin-tazobactam 17%, cefotaxime 14%, ertapenem 12%, gentamicin 3% and imipenem 0%. ESBL-producing Enterobacteriaceae were found in samples from 10 patients (5%). Three patients had five E. coli isolates producing AmpC enzymes. CONCLUSIONS: This study shows a high rate of resistance among Enterobacteriaceae against antibiotics which are commonly used in Sweden and should have implications for the future choice of antibiotics for surgical patients.

Control of microbial attachment by inhibition of ATP and ATP-mediated autoinducer-2.

In this study, 2,4-dinitrophenol (DNP), a typical chemical uncoupler, was employed to investigate the possible roles of ATP and autoinducer-2 (AI-2) of suspended microorganisms in attachment onto nylon membrane and glass slide surfaces. Results showed that DNP could disrupt ATP synthesis, subsequently led to a reduced production of AI-2 which is a common signaling molecule for cellular communication. Attachment of suspended microorganisms exposed to DNP was significantly suppressed as compared to microorganisms without contact with DNP. These suggest that an energized state of suspended microorganisms would favor microbial attachment to both nylon membrane and glass slide surfaces. The extent of microbial attachment was found to be positively related to the AI-2 content of microorganisms. This study offers insights into the control of biofouling by preventing initial microbial attachment through inhibition of energy metabolism.