Bacterial Colony Counts Research Articles

Polymer-based Silver Nanoparticle Coated Pedicle Screws Inhibits Biofilm Formation-a Novel Experimental Model in Rabbits

Introduction Infection in spinal implant is of great concern. Anti-infection strategies must be tested in relevant animal models that will lead to appropriate clinical studies. A novel spine implant model was designed to study the antimicrobial effect of a modified Titanium (Ti) pedicle screws with methiciline resistant Staphyloccoccus Aerous (MRSA) in multiple surgical sites in the lumbar spine of a rabbit. Material and Methods Twenty two New Zealand White rabbits were divided into two groups: group 1: infected unmodified Ti screw group ( n = 10), group 2: infected polyethylene glycol grafted polypropylene based Silver nanoparticle (PP-g-PEG-Ag) covered Ti screw group ( n = 10), and two rabbits as control-sterile group. In all groups left L4- right L6 vertebra levels were exposed and screws were drilled to transverse processes after contamination of burr holes with 0.1 ml of 106 CFU MRSA solutions in group 1 and 2. After 21 days, samples were collected and infection was analyzed via light and scanning electron microscopy and culturing. Silver nanoparticles (Ag-NP) on the screws and tissues were assayed pre and postoperatively. Results The bacterial colony count for modified-Ti screw group was lower compared with unmodified Ti screw (17,2 vs 200 × 103 CFU/mL, p = 0,029) with less biofilm formation. There was no difference in duration of surgery among groups and within the surgical sites. Ag-NPs were detected on the screw surface postoperatively. Conclusion This novel experimental design of implantation in rabbits is easy to apply and resembles human stabilization technique. Modified Ti screws were shown to have antimicrobial effect with especially inhibiting the biofilm formation. This anchored Ag NPs which remained after 21st day of implantation shows that it is resistant to tapping forces of the screw.

Evaluation of a lysostaphin-fusion protein as a dry-cow therapy for Staphylococcus aureus mastitis in dairy cattle

This study evaluated the efficacy of a recombinant lysostaphin fused to a protein transduction domain (rLYS-PTD) as a dry-cow therapy for the treatment of experimentally induced chronic, subclinical Staphylococcus aureus mastitis. Twenty-two Holstein dairy cows were experimentally infected with Staph. aureus in a single pair of diagonal mammary quarters approximately 45d before dry off. Staphylococcus aureus-infected mammary quarters of cows were randomly assigned to 1 of 2 treatment groups at dry off: (1) 279mg of rLYS-PTD in 50mL of vehicle (n=11 cows; 22 quarters) or (2) 50mL of vehicle solution (n=11 cows; 22 quarters) by intramammary infusion. All cows were followed for 30d postpartum to determine cure rates using bacteriologic culture, somatic cell counts, and clinical mastitis scores. No cures were recorded in either the treatment or control groups. Milk somatic cell count, bacterial colony counts, and mastitis scores did not significantly differ between treatment groups. In conclusion, rLYS-PTD was not an effective dry-cow therapeutic for chronic, subclinical Staph. aureus mastitis at the tested dose and formulation.

Antimicrobial Effect of Polymer-Based Silver Nanoparticle Coated Pedicle Screws: Experimental Research on Biofilm Inhibition in Rabbits.

Antimicrobial effect of a novel silver-impregnated pedicle screw in rabbits. A novel spine implant model was designed to study the antimicrobial effect of a modified Titanium (Ti) pedicle screws with methicillin-resistant Staphylococcus aureus (MRSA) in multiple surgical sites in the lumbar spine of a rabbit. Infection in spinal implant is of great concern. Anti-infection strategies must be tested in relevant animal models that will lead to appropriate clinical studies. Fourteen New Zealand white rabbits were divided into 2 groups: group 1: infected unmodified Ti screw group (n = 6), and group 2: infected polyethylene glycol grafted, polypropylene-based silver nanoparticle (PP-g-PEG-Ag) covered Ti screw group (n = 6), and 2 rabbits as sterile (sham-operated and control) group. In all groups, left L4-right L6 vertebra levels were exposed and screws were drilled to transverse processes after contamination of burr holes and surrounding tissue with 0.1 mL of 10 colony forming units (CFU) MRSA solutions in groups 1 and 2. After 21 days, samples were collected and infection was analyzed via light and scanning electron microscopy and culturing. Silver nanoparticles (Ag-NP) on the screws and tissues were assayed pre and postoperatively. The bacterial colony count for modified-Ti screw group was lower than for unmodified Ti screw (17.2 versus 200 x 10(3) CFU/mL, P = 0.029) with less biofilm formation. There was no difference in duration of surgery among groups and within the surgical sites. Ag-NPs were detected on the screw surface postoperatively. This novel experimental design of implantation in rabbits is easy to apply and resembles human stabilization technique. Modified Ti screws were shown to have antimicrobial effect especially inhibiting the biofilm formation. This anchored Ag NPs that remained after 21st day of implantation shows that it is resistant to tapping forces of the screw.

Real-time bacterial microcolony counting using on-chip microscopy.

Observing microbial colonies is the standard method for determining the microbe titer and investigating the behaviors of microbes. Here, we report an automated, real-time bacterial microcolony-counting system implemented on a wide field-of-view (FOV), on-chip microscopy platform, termed ePetri. Using sub-pixel sweeping microscopy (SPSM) with a super-resolution algorithm, this system offers the ability to dynamically track individual bacterial microcolonies over a wide FOV of 5.7 mm × 4.3 mm without requiring a moving stage or lens. As a demonstration, we obtained high-resolution time-series images of S. epidermidis at 20-min intervals. We implemented an image-processing algorithm to analyze the spatiotemporal distribution of microcolonies, the development of which could be observed from a single bacterial cell. Test bacterial colonies with a minimum diameter of 20 μm could be enumerated within 6 h. We showed that our approach not only provides results that are comparable to conventional colony-counting assays but also can be used to monitor the dynamics of colony formation and growth. This microcolony-counting system using on-chip microscopy represents a new platform that substantially reduces the detection time for bacterial colony counting. It uses chip-scale image acquisition and is a simple and compact solution for the automation of colony-counting assays and microbe behavior analysis with applications in antibacterial drug discovery.

Impaired cellular immune response to injected bacteria after knockdown of ferritin genes in the hard tick Haemaphysalis longicornis

Iron is an indispensable element for most microorganisms, including many pathogenic bacteria. Iron-withholding is a known component of the innate immunity, particularly of vertebrate hosts. Ticks are vectors of multiple pathogens and reports have shown that they naturally harbor several bacterial species. Thus, tick innate immunity must be crucial in limiting bacterial population to tolerable level that will not cause adverse effects. We have previously characterized two types of the iron-binding protein ferritin (HlFER) in the hard tick Haemaphysalis longicornis, known to be a vector of some protozoan parasites and rickettsiae, and showed their antioxidant function and importance in blood feeding and reproduction. Here we examined the possible role of HlFERs in tick immunity against bacterial infection. After silencing Hlfer genes, adult ticks were injected with live enhanced green fluorescence protein-expressing Escherichia coli, and then monitored for survival rate. Hemolymph that included hemocytes was collected for microscopic examination to observe cellular immune response, and for E. coli culture to determine bacterial viability after injection in the ticks. The expression of some antimicrobial peptides in whole ticks was also analyzed by RT-PCR. Hlfer-silenced ticks had a significantly lower survival rate than control ticks after E. coli injection. Greater number of bacteria inside and outside the hemocytes and higher bacterial colony counts after culture with hemolymph were also observed in Hlfer-silenced ticks. However, no difference on the expression of antimicrobial peptides was observed. These results suggest that ferritin molecules might be important in the cellular immune response of ticks to some bacteria.

In-Use Evaluation of Peracetic Acid for High-Level Disinfection of Endoscopes.

Many high-level disinfectants have been used for disinfection of endoscopes such as 2% glutaraldehyde (GA), 0.55% ortho-phthalaldehyde (OPA), and peracetic acid (PAA). Both GA and OPA are widely used in disinfection of endoscopes and have been previously discussed, but there is little research on the practical use of PAA as an endoscope disinfectant. An experimental model of a flexible gastrointestinal endoscope being contaminated with 9 strains of microorganism was designed. After the cleaning and disinfecting procedure was completed, we evaluated the biocidal activity (850 ppm PAA, 2% GA, and 0.55% OPA) on our flexible gastrointestinal endoscope model. We also evaluated sterilization effectiveness of PAA on other bacteria, including some antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile). The residual bacterial colony count number of the PAA-disinfected endoscope was significantly lower than that of the GA- and OPA-disinfected endoscopes. The biocidal effect and efficiency of the endoscope disinfection by PAA appeared to be better than either the GA- or OPA-disinfected endoscope. PAA has demonstrated a good sterilization effect on other bacterial species; of particular note are common antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. The results of this study demonstrate that PAA is a fast and effective high-level disinfectant for use in the reprocessing of flexible endoscopes.

Particle Size-Dependent Antibacterial Activity and Murine Cell Cytotoxicity Induced by Graphene Oxide Nanomaterials

Recent studies have indicated that graphene and its derivative graphene oxide (GO) engage in a wide range of antibacterial activities with limited toxicity to human cells. Here, we systematically evaluate the dependence of GO toxicity on the size of the nanoparticles used in treatments: we compare the cytotoxic effects of graphene quantum dots (GQDs, <15 nm), small GOs (SGOs, 50–200 nm), and large GOs (LGOs, 0.5–3 μm). We synthesize the results of bacterial colony count assays and SEM-based observations of morphological changes to assess the antibacterial properties that these GOs bring into effect againstE. coli. We also use Live/Dead assays and morphological analysis to investigate changes to mammalian (Murine macrophage-like Raw 264.7) cells induced by the presence of the various GO particle types. Our results demonstrate that LGOs, SGOs, and GQDs possess antibacterial activities and cause mammalian cell cytotoxicity at descending levels of potency. Placing our observations in the context of previous simulation results, we suggest that both the lateral size and surface area of GO particles contribute to cytotoxic effects. We hope that the size dependence elucidated here provides a useful schematic for tuning GO-cell interactions in biomedical applications.

Comparison of Antibacterial Effects of 810 and 980- nanometer Diode Lasers on Enterococcus Faecalis in the Root Canal System -An in vitro study.

Background and aim: Use of laser technology in endodontics has greatly increased in the recent years due to the introduction of new wavelengths and methods and optimal antimicrobial and smear layer removal properties of lasers. This in vitro study aimed to compare the antibacterial effects of diode lasers of 810 nm and 980 nm wavelength on Enterococcus faecalis (E. faecalis) biofilm in the root canal system. Materials and methods: Fifty single-canal human anterior teeth were cleaned, shaped, sterilized and randomly divided into four groups namely two experimental, one positive and one negative control group. The experimental and positive control groups were inoculated with E. faecalis and incubated for two weeks. The experimental group one (n=20) received 810 nm diode laser irradiation (1.5W) while the experimental group two (n=20) was subjected to 980 nm diode laser irradiation (1.5W). The E. faecalis colony forming units (CFUs) were counted in each root canal before and after laser irradiation. Results: Laser irradiation significantly decreased the bacterial colony count in both experimental groups. The reduction in microbial count was significantly greater in 810 nm laser group compared to 980 nm laser group. Conclusion: Irradiation of both 810 and 980 nm lasers significantly decreased the E. faecalis count in the root canal system; 810 nm laser was more effective in decreasing the intracanal microbial load.

A Diet Containing Beta-Hydroxy-Beta-Methylbutyrate, L-Glutamine and L-Arginine Ameliorates Chemoradiation-Induced Gastrointestinal Injury in Rats

The aim of this study was to investigate the effects of a specific diet, containing beta-hydroxy-beta-methylbutyrate, L-glutamine and L-arginine (HMB/Glu/Arg), on chemoradiation-induced injuries of the rat gastrointestinal mucosa. Wistar albino rats were divided into 4 groups: control (n = 5); radiation (n = 14); 5-fluorouracil treatment (5-FU; n = 14); and radiation and 5-FU treatment (n = 14). Rats were fed either a standard diet or a specific diet (SpD) containing HMB/Glu/Arg supplementation for 7 days prior to radiation exposure and/or 5-FU treatment. The irradiated groups were exposed to an 1 Gy dose of 6 MV x rays delivered to the who-abdominal. The animals receiving 5-FU treatment were given a 100 mg/kg dose of the drug. In the radiation and 5-FU treatment group, the 5-FU was administered 30 min prior to irradiation. After irradiation and/or 5-FU treatment, feeding with either the standard rat diet or specific diet continued as before. All animals were sacrificed on day 4 after irradiation and 5-FU treatment. Data collected included microbiological, histological and immunohistochemical end points. We found that bacterial colony counts in the ceca and mesenteric lymph nodes of irradiated rats treated with 5-FU were significantly lower in the specific diet (SpD) group than in the standard diet group (P = 0.002-0.05). Morphometrically, gastric, duodenal and colonic mucosal injuries were less severe in the irradiated animals fed the specific diet, as well as the 5-FU-treated animals fed the specific diet, compared to the similarly treated standard diet groups. Apoptosis, measured by TUNEL, revealed significantly lower numbers of TUNEL positive cells in irradiated animals fed the specific diet, and irradiated animals treated with 5-FU and fed the specific diet compared to irradiated animals fed the standard diet, and irradiated animals treated with 5-FU and fed the standard diet. In the 5-Fu-treated and SpD group, the extent of apoptosis was significantly lower than that of the 5-Fu-treated and standard diet group in both the stomach and duodenum (P = 0.0001), but not in the colon. Apoptosis, measured by caspase 3 staining, was significantly less in all three organs of the SpD groups. In conclusion, these findings suggest that a diet supplemented with HMB/Glu/Arg may ameliorate the effect of radiation-induced gastrointestinal injury, coinciding with reduced bacterial growth.

Bacterial colony counting by Convolutional Neural Networks.

Counting bacterial colonies on microbiological culture plates is a time-consuming, error-prone, nevertheless fundamental task in microbiology. Computer vision based approaches can increase the efficiency and the reliability of the process, but accurate counting is challenging, due to the high degree of variability of agglomerated colonies. In this paper, we propose a solution which adopts Convolutional Neural Networks (CNN) for counting the number of colonies contained in confluent agglomerates, that scored an overall accuracy of the 92.8% on a large challenging dataset. The proposed CNN-based technique for estimating the cardinality of colony aggregates outperforms traditional image processing approaches, becoming a promising approach to many related applications.

Automatic Counting and Classification of Bacterial Colonies Using Hyperspectral Imaging

Detection and counting of bacterial colonies on agar plates is a routine microbiology practice to get a rough estimate of the number of viable cells in a sample. There have been a variety of different automatic colony counting systems and software algorithms mainly based on color or gray-scale pictures although manual counting is still common. In microbiology, identification of presumptive-positive colonies on agar plates is predominantly done manually, which is laborious and time-consuming. This paper addresses a problem related to automatic colony segmentation and classification that can count the number of colonies according to their types. Hyperspectral imaging was used to develop a colony segmentation algorithm for detecting non-O517 Shiga-toxin producing Escherichia coli (STEC) pathogens on Rainbow agar. Hyperspectral absorbance image analysis in the visible and near-infrared spectral range from 400 to 1000 nm showed that colony morphology including size and texture was dependent on wavelength. The non-O157 STEC colonies showed dome-like absorbance profiles with local absorbance maxima. Touching colonies, causing problems for accurate counting and identification, were separated by optimally tessellating the mesh structure of local maximal points. The 428 nm was determined as the optimal wavelength for non-O157 STEC colony segmentation. The accuracy of the colony segmentation and counting algorithm was over 99 %. The average of the colony classification algorithm using automated colony segments was 92.5 %.

Treatment of Staphylococcus aureus-induced chronic osteomyelitis with bone-like hydroxyapatite/poly amino acid loaded with rifapentine microspheres.

PurposeThe purpose of this study was to investigate the curative effect of bone-like hydroxyapatite/poly amino acid (BHA/PAA) as a carrier for poly(lactic-co-glycolic acid)-coated rifapentine microsphere (RPM) in the treatment of rabbit chronic osteomyelitis induced by Staphylococcus aureus.MethodsRPM was prepared through an oil-in-water emulsion solvent evaporation method, and RPM was combined with BHA/PAA to obtain drug-loaded, slow-releasing materials. Twenty-six New Zealand white rabbits were induced to establish the animal model of chronic osteomyelitis. After debridement, the animals were randomly divided into three groups (n=8): the experimental group (with RPM-loaded BHA/PAA), the control group (with BHA/PAA), and the blank group. The RPM-loaded BHA/PAA was evaluated for antibacterial activity, dynamics of drug release, and osteogenic ability through in vitro and in vivo experiments.ResultsIn vitro, RPM-loaded BHA/PAA released the antibiotics slowly, inhibiting the bacterial growth of S. aureus for up to 5 weeks. In vivo, at week 4, the bacterial colony count was significantly lower in the experimental group than in the control and blank groups (P<0.01). At week 12, the chronic osteomyelitis was cured and the bone defect was repaired in the experimental group, whereas the infection and bone defect persisted in the control and blank groups.ConclusionIn vitro and in vivo experiments demonstrated that RPM-loaded BHA/PAA effectively cured S. aureus-induced chronic osteomyelitis. Therefore, BHA/PAA has potential value as a slow-releasing material in clinical setting. Further investigation is needed to determine the optimal dosage for loading rifapentine.

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.

Antibacterial efficacy of prophylactic besifloxacin 0.6% and moxifloxacin 0.5% in patients undergoing cataract surgery.

BackgroundThe purpose of this study was to investigate the ocular bacterial flora in patients scheduled to undergo cataract surgery and compare the antibacterial effects of besifloxacin ophthalmic suspension 0.6% and moxifloxacin ophthalmic solution 0.5% in these patients.MethodsThis was a prospective, randomized, laboratory-masked clinical trial. Patients received besifloxacin or moxifloxacin “quater in die” or QID (four times a day) for 3 days before cataract surgery in the surgical eye and 1 hour before surgery in the nonsurgical fellow eye. Conjunctival and eyelid swabs were obtained from both eyes at baseline and after treatment, on the day of surgery (Visit 2). Swabs were processed for bacterial colony counts (in terms of colony-forming units) and species identification. In vitro antibiotic susceptibilities of isolates were determined using Clinical and Laboratory Standards Institute breakpoints.ResultsFifty-nine patients (n=28 besifloxacin, n=31 moxifloxacin) completed the study. The majority (73%) of conjunctival samples were culture negative at baseline. The most frequent isolates were coagulase-negative staphylococci (CoNS, 89%), specifically Staphylococcus epidermidis (72%). Both fluoroquinolones reduced the lid CFU values when administered QID for 3 days (P≤0.019), but only besifloxacin reduced the lid CFU estimate 1 hour following instillation of a single drop (P=0.039). Fewer besifloxacin-treated eyes had lids that were culture positive for CoNS at Visit 2 compared with moxifloxacin-treated eyes regardless of dosing regimen (P≤0.03). The minimum inhibitory concentration (MIC90) of besifloxacin against methicillin-resistant S. epidermidis (MRSE) was eightfold lower than that of moxifloxacin.ConclusionBesifloxacin appeared more effective in reducing bacterial counts on eyelids of patients undergoing cataract surgery, with significant reductions as early as 1 hour postdose, compared with moxifloxacin. Besifloxacin was more active in vitro against MRSE.

Effects of vapocoolant spray on skin sterility prior to intravenous cannulation

Alkane vapocoolant sprays evaporate rapidly, lower skin temperature and result in a temporary interruption in pain sensation. They reduce the pain of intravenous cannulation. However, concern exists that they may recontaminate the sterile cannulation site. To determine the effects of vapocoolant spray on skin sterility prior to cannulation. Fifty patients from the emergency department of a large tertiary metropolitan hospital were enrolled in this study. Bacterial skin swabs were taken from the dorsum of both hands of each patient. From one hand, a swab was taken following standard chlorhexidine disinfection, and a second swab was taken following the application of vapocoolant spray. From the other hand, a swab was taken from unprepared (non-disinfected) skin, and a second swab was taken following vapocoolant application. Skin swabs were sent for microbiological culture and quantitative comparison. The administration of vapocoolant after skin disinfection did not increase the bacterial colony count significantly: median 0.0 [interquartile range (IQR) 0.0] vs 0.0 (IQR 0.0) (P=0.71). The administration of vapocoolant to the unprepared skin decreased the colony count significantly: median 33.5 (IQR 68) vs 3.0 (IQR 11) (P<0.001). Alkane vapocoolant spray does not recontaminate the skin after disinfection, and should pose no increased risk of infection when used as an anaesthetic agent prior to intravenous cannulation following disinfection. While it does have inherent bactericidal activity, this is not sufficient for it to be used as the sole disinfectant.

Microbiological Stability of Canned Tuna Produced in Italy and in Non-European Countries.

The results of a study on the microbiological stability of canned tuna produced by Italian companies and similar canned products manufactured in countries outside Europe are reported herein. The study involved 38 samples of canned tuna of various brands, of which 14 were produced by companies outside Europe and 24 by Italian companies. Qualitative and quantitative microbiological tests were conducted for the following parameters: bacterial colony counts at 30°C, total coliforms, total Enterobacteriaceae, sulphite-reducing anaerobes, Salmonella spp., Bacillus cereus, Escherichia coli, Staphylococcus aureus, yeasts and molds. Bacterial loads and mold contamination were respectivelyin found in 8/14 (57%) samples from outside EU and 7/24 (29%) Italian samples. The bacterial flora was represented by Gram-positive bacteria (Staphylococcus warneri, Staphylococcus lentus, Streptococcus mitis, Enterococcus faecalis, Leuconostoc mesenteroides), Gram-negative bacteria (Sphingomonas paucimobilis, Acinetobacter iwoffii, Rhizobium radiobacter), spore-forming bacteria (Bacillus vallismortis), while the fungal species was represented by Penicillium spp., Rhizopus spp., Rhodotorula spp. and Alternaria spp. Excluding anomalies in the thermal treatment process of products and any contamination after treatment, the contaminations encountered in both cases were most likely due to insufficient production quality standards and the quality of the raw material used. These results may require a redefinition of the concept of commercial stability as hitherto stated.

Investigation of hand hygiene among caretakers of children with chemotherapy and intervention effect

Objective To investigate hand hygiene awareness and performance for caretakers of children with chemotherapy, and explore effective intervention measures. Methods For 60 caretakers of children with chemotherapy in Hematology Department, we carried out a questionnaire survey of hand hygiene, and tracked the hand washing implementation. Also we carried on a six steps hand washing technique training for the caretakers, then compared and analyzed the hand washing qualified rate before and after the technique training. Results The hand washing cognitive rate of the caretakers when they directly contacting with sick children and before feeding food or medicine for sick children were 88.33% and 93.33%, and the implementation rate of those situation were 76.67% and 89.13% respectively. In addition, the hand washing cognitive rates of before contacting sick children′s objects and after contacting other people (including other sick children) were just 21.67% and 41.67%, and the implementation rates were 14.89% and 28.95% respectively. Before and after the six steps hand washing technique training, the bacterial colony count of the caretakers hands were (82.36±53.32)cfu/cm2 and (16.21±18.83)cfu/cm2 (t=9.061, P<0.01), but after training, the pathogenic bacteria detection rate was 31.67% and the qualified rates 61.67% with statistical difference (χ2=28.420, 27.638, respectively; P<0.01). Conclusions The hand hygiene cognition for caretakers of children with chemotherapy is relatively low, and the implementation and hand washing qualified rate are unacceptable. The health education propaganda of hand hygiene and hand washing technique training for caretakers should be further strengthen. Hospital should supervise and urge the hand hygiene implementation, in order to improve the hand washing qualified rate of caretakers, reduce the nosocomial infection through hand contact, and protect the health and safety of children with chemotherapy. Key words: Antineoplastic combined chemotherapy protocols; Children; Caretakers; Hand hygiene

An in situ antimicrobial susceptibility testing method based on in vivo measurements of chlorophyll α fluorescence

Up to now antimicrobial susceptibility testing (AST) methods are indirect and generally involve the manual counting of bacterial colonies following the extraction of microorganisms from the surface under study and their inoculation in a separate procedure. In this work, an in situ, direct and instrumental method for the evaluation and assessment of antibacterial properties of materials and surfaces is proposed. Instead of indirectly determining antibacterial activity using the typical gram(−) test organisms with the subsequent manual colony count or inhibition zone measurement, the proposed procedure, employs photosynthetic gram(−) cyanobacteria deposited directly onto the surface under study and assesses cell proliferation and viability by a quick, accurate and reproducible instrumental chlorophyll fluorescence spectrophotometric technique. In contrast with existing methods of determination of antibacterial properties, it produces high resolution and quantitative results and is so versatile that it could be used to evaluate the antibacterial properties of any compound (organic, inorganic, natural or man-made) under any experimental conditions, depending on the targeted application.

A newly recognized Mesozoic–Recent interspecific association: calcifying bacteria on decapod crustaceans

Using microscopy and spectroscopy tools, we succeeded in identifying undescribed diminutive epibionts (as epibiotic bacterial colonies) both on exceptionally well-preserved fossil shrimps and on extant taxa (N. Robin, S. Bernard, J. Miot, M.-M. Blanc-Valleron, S. Charbonnier & G. Petit, submitted). This study outlines the ecological parameters of this totally newly recognized interspecific association. To this aim, the systematics and environmental setting of fossil and modern decapod hosts are described; count of bacterial colonies is made to assess prevalence and intensity; scanning electron microscopy is used to illustrate colonial growth patterns; and histological sections of the extant colonies nested in cuticle are stained to determine their incidence on the carapace of their decapod hosts. Thus, the prevalent and intense association is found on decapods of the superfamily Penaeoidea Rafinesque-Schmaltz 1815 occupying up to 2 cm2 of the entire carapace. The association is here observed in deep environments such as that of the Jurassic La Voulte-sur-Rhône Lagerstätte. A non-random distribution of colonial growth patterns is determined; it illustrates a favourite access site along the ventral margin of the shrimp carapace. SEM images and stained sections reveal strong colony embedment within the cuticle, but also damage such as erasing of the cuticular layers. This bioeroding effect, possibly linked to a feeding benefit to the bacteria, brings this interspecific association that has existed, for at least 160 myr, near to parasitism. In addition to illustrating a rare case of interaction in Recent forms that could be described due to previous recognition in fossils, it constitutes a textbook example of the preservation of intimate interactions through geological time.

Development of a Score Based on Urinalysis to Improve the Management of Urinary Tract Infection in Children

Objectives: Our aim is to develop a score that may help in reducing the misuse of antibiotics in treatment of urinary tract infection before appearance of urine culture. Background: The need for reducing unnecessary antibiotic treatment is being emphasized in the management of urinary tract infections (UTI), a disease frequent in childhood. An ideal test should provide early diagnosis without the waiting times of urine culture, but even a simple test of exclusion could significantly improve patient management. Methods: We evaluated the sensitivity, specificity, negative and positive predictive value of urine analysis, dipstick (leukocyte esterase and nitrite) and bacterial colony count in children with suspected UTI. Multivariable logistic regression analysis was used to identify the set of variables that best predict positive culture results and develop a numerical risk score. Results: Of 200 children were having symptoms of UTI, 93 child had confirmed UTI with prevalence 46.5%. Parameters significantly associated with the presence of infection in multivariable analysis were age 9-12 years (p < 0.05), leukocyte esterase positive (p < 0.001), nitrite positive (p < 0.05), pus cell >10/HPF (p < 0.05), RBCs>10/HPF (p < 0.05) and bacteria ≥ 10^6 (p < 0.05).The derived score ranged from 1 to 7, with higher values indicating higher risk of UTI. Conclusion: This routine method could improve the management of UTI in children by early identifying patients with low probability of infection, for which antibiotic treatment can be withheld until the results of urine culture become available.