Microbiologic evaluation of microfiber mops for surface disinfection

BACKGROUND: Recently, health care facilities have started to use a microfiber mopping technique rather than a conventional, cotton string mop to clean floors. METHODS: The effectiveness of microfiber mops to reduce microbial levels on floors was investigated. We compared the efficacy of microfiber mops with that of conventional, cotton string mops in 3 test conditions (cotton mop and standard wringer bucket, microfiber mop and standard wringer bucket, microfiber system). Twenty-four rooms were evaluated for each test condition. RODAC plates containing D/E Neutralizing Agar were used to assess "precleaning" and "postcleaning" microbial levels. RESULTS: The microfiber system demonstrated superior microbial removal compared with cotton string mops when used with a detergent cleaner (95% vs 68%, respectively). The use of a disinfectant did not improve the microbial elimination demonstrated by the microfiber system (95% vs 95%, respectively). However, use of disinfectant did significantly improve microbial removal when a cotton string mop was used (95% vs 68%, respectively). CONCLUSION: The microfiber system demonstrated superior microbial removal compared with cotton string mops when used with a detergent cleaner. The use of a disinfectant did not improve the microbial elimination demonstrated by the microfiber system.     

Defining lower airway bacterial infection in children with chronic endobronchial disorders

Background

Differentiating lower airway bacterial infection from possible upper airway contamination in children with endobronchial disorders undergoing bronchoalveolar lavage (BAL) is important for guiding management. A diagnostic bacterial load threshold based on inflammatory markers has been determined to differentiate infection from upper airway contamination in infants with cystic fibrosis, but not for children with protracted bacterial bronchitis (PBB), chronic suppurative lung disease (CSLD), or bronchiectasis.

Methods

BAL samples from children undergoing bronchoscopy underwent quantitative bacterial culture, cytologic examination, and respiratory virus testing; a subset also had interleukin‐8 examined. Geometric means (GMs) of total cell counts (TCCs) and neutrophil counts were plotted by respiratory pathogen bacterial load. Logistic regression determined associations between age, sex, Indigenous status, antibiotic exposure, virus detection and bacterial load, and elevated TCCs (>400 × 10³ cells/mL) and airway neutrophilia (neutrophils >15% BAL leukocytes).

Results

From 2007 to 2016, 655 children with PBB, CSLD, or bronchiectasis were enrolled. In univariate analyses, Indigenous status and bacterial load ≥10⁵ colony‐forming units (CFU)/mL were positively associated with high TCCs. Viruses and bacterial load ≥10⁴ CFU/mL were positively associated with neutrophilia; negative associations were seen for Indigenous status and macrolides. In children who had not received macrolide antibiotics, bacterial load was positively associated in multivariable analyses with high TCCs at ≥10⁴ CFU/mL and with neutrophilia at ≥10⁵ CFU/mL; GMs of TCCs and neutrophil counts were significantly elevated at 10⁴ and 10⁵ CFU/mL compared to negative cultures.

Conclusions

Our findings support a BAL threshold ≥10⁴ CFU/mL to define lower airway infection in children with chronic endobronchial disorders.

     

Experimental Contamination of a Closed Endotracheal Suction System: 24 h vs 72 h

Abstract Objective:   To ascertain the desirability of replacing closed suction systems after 72 h rather than after 24 h (manufacturer’s recommendations) because it is possible that a reduction in the frequency of manipulations might reduce the risk of exogenous nosocomial pneumonia. We investigated the presence of time-dependent differences (after 24 h and 72 h) in pathogen survival/growth in artificially contaminated closed suction catheters (OptiFlo^?). Design:   The trial simulated bacterial contamination of the airways using a suspension of 2 × 10³ CFU/ml of Staphylococcus aureus or Pseudomonas aeruginosa. Contamination was performed on a total of 80 catheters. Forty were contaminated a total of eight times every 45–60 min. Another 40 catheters underwent the same procedure 24 times over three consecutive days. Microbiological analysis of the catheters took place after 24 h and 72 h, respectively. Results:   The mean S. aureus load was 9.4 CFU/catheter after eight suction procedures and 6.2 CFU/catheter after 24 suction procedures (3 days). Mean growth of P. aeruginosa was 5.3 CFU/catheter, and 8.2 CFU/catheter after 3 days. There was no statistically significant difference between day 1 and 3 for S. aureus (p = 0.474), but there was for P. aeruginosa (p = 0.004). Conclusion:   Our findings show that, from an experimental point of view, it remains controversial whether routine change of closed suction catheters can be extended from 24 h to 72 h. However, clinical evidence suggests that prolonged use of a closed suctioning system is safe.     

Assessment of the effect of hand dryers used in shopping malls on hand hygiene

BackgroundHand drying is one of the most important factors affect hand hygiene. This study was conducted to investigate the effect of hand dryers used in the restrooms located on the food court floors in shopping malls in Turkey on hand hygiene.MethodsHands were washed for at least 20 seconds by following hygienic hand washing procedures of the World Health Organization. Swab samples were taken from the wet hands after hand washing, then from the dry hands, which were dried under the hand dryers and from the air blowing part of the hand dryers. Samples were cultured on agar plates that were directly exposed to the air-blowing part of the hand dryers.ResultsIt was found that total coliform bacteria were 0.000 colony-forming unit (CFU)/petri in wet and dried hand, 3.437 CFU/petri in blown air and 5.250 CFU/petri in swab samples. Staphylococcus aureus was found to be 0.125, 64.125, 26.375, and 388.750 CFU/petri, respectively. Total bacteria count was found to be 0.687, 48.750, 35.625, and 595.000 CFU/petri, respectively. S. aureus and the total bacterial load were higher in the blower outlet of the hand dryers than washed hand, blown air and dried hand (P < .05). The bacteria count in the unfiltered hand dryers was higher than that in the filtered hand dryers (P < .05).ConclusionsUsing hand dryers would negatively affect hand hygiene even if hands were washed following hygienic hand washing procedures.     

In vitro antiplasmodial activity of Clathria vulpina sponge associated bacteria against Plasmodium falciparum

ObjectiveTo identify the possible antiplasmodial drugs from bacteria associated with marine sponge Clathria vulpina (C. vulpina).MethodsThe C. vulpina samples were collected from Thondi coast and subjected to enumeration and isolation of associated bacteria. Filtered and sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg/mL) from isolated bacterial strains were screened for antiplasmodial activity against Plasmodium falciparum. Potential extracts were also screened for biochemical constituents.ResultsThirty one bacterial strains were isolated from twelve sponge samples collected from Thondi coast and screened for antiplasmodial assay. The count of bacterial strains were maximum in November 2007 (19×10⁴ CFU/g) and the average count was maximum during the monsoon season (110×10³ CFU/g). The antiplasmodial activity of strain THB15 was highly comparable (IC₅₀ = 20.73 μg/mL) with the positive control chloroquine (IC₅₀ = 19.59 μg/mL) and 21 bacterial strains showed IC₅₀ value of more than 100 μg/mL. Statistical analysis reveals that, significant in vitro antiplasmodial activity (P<0.05) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes showed no morphological changes in erythrocytes by the ethyl acetate extract of bacterial strains after 48 h of incubation. The in vitro antiplasmodial activity might be due to the presence of sugars and alkaloids in the ethyl acetate extracts of bacterial strains.ConclusionThe ethyl acetate extract of THB15 possesses lead compounds for the development of antiplasmodial drugs.     

In vitro antiplasmodial activity of marine sponge Stylissa carteri associated bacteria against Plasmodium falciparum

ObjectiveTo identify the possible antiplasmodial drugs from bacteria associated with marine sponge Stylissa carteri (S. carteri).MethodsThe S. carteri samples were collected from Thondi coast and subjected for enumeration and isolation of associated bacteria. Filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μ g/mL) from isolated bacterial strains were screened for antiplasmodial activity against Plasmodium falciparum (P. falciparum) and potential extracts were also screened for biochemical constituents.ResultsTwelve samples of S. carteri were collected and subjected for enumeration and isolation of associated bacteria. The count of bacterial strains were maximum in November 2007 (34 × 10⁴ CFU/g) and the average count was maximum during the monsoon season (203 × 10³ CFU/g). Thirty two morphologically different bacterial strains were isolated from S. carteri and the ethyl acetate bacterial extracts were screened for antiplasmodial activity against P. falciparum. The antiplasmodial activity of a strain THB17 (IC₅₀ 20.56 μ g/mL) extract is highly comparable with the positive control chloroquine (IC₅₀ 19.59 μ g/mL) and 13 bacterial extracts which showed IC₅₀ value of more than 100 μ g/mL. Statistical analysis reveals that, significant in vitro antiplasmodial activity (P<0.05) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes showed no morphological changes in erythrocytes by the ethyl acetate extract of bacterial strains after 48 h of incubation. The in vitro antiplasmodial activity might be due to the presence of reducing sugars and alkaloids in the ethyl acetate extracts of bacterial strains.ConclusionsThe ethyl acetate extract of THB17 possesses lead compounds for the development of antiplasmodial drugs.     

Assessment of the contamination potentials of some foodborne bacteria in biofilms for food products

ObjectiveTo assess biofilms formed by different bacterial strains on glass slides, and changes in biofilm mass and biofilm-associated cell populations after brief contacts between biofilms and either media agar or food products.MethodsTwo Listeria monocytogenes and Escherichia coli (E. coli) strains and a single Staphylococcus aureus (S. aureus) strain were inoculated separately in tryptic soy broth containing glass coupons incubated for 24, 48 or 72 h at 37 °C. The biofilms formed by individual bacterial strains and biofilm-associated cell populations were determined. Biofilms were subsequently allowed to have brief contacts (1-3 times), through gentle touching, with either agar, meat or soft white cheese (2 cm³). Changes in biofilm mass on glass slides and cell populations embedded in biofilms were quantified.ResultsA nonpathogenic E. coli formed more biofilms than an E. coli O157:H7 strain. Biofilms formed by S. aureus and Listeria monocytogenes were essentially similar. The biofilm mass increased as incubation time increased within 48 h of incubation and was not positively correlated with cellulose production. Biofilm mass at 48 and 72 h of incubation was not significantly different. More frequent contacts with agar or foods did not remove more biofilms or biofilm-associated cells from glass slides. More S. aureus biofilms were removed followed by Listeria and E. coli biofilms. Mean contamination of agar or food models was 0.00 to 7.65 log CFU/cm². Greater contaminations in cell populations were observed with S. aureus and Listeria biofilms.ConclusionsThe results provide a clearer assessment of contaminating potential of foods that comes in contact with them.     

Special precautions reduce oropharyngeal contamination in bronchoalveolar lavage for bacteriologic studies

Despite the use of quantitative culture, oropharyngeal contamination of bronchoalveolar lavage (BAL) specimens is still a factor that limits the usefulness of this technique in the diagnosis of lower respiratory tract infection. To investigate whether special precautions could reduce contamination, 20 noninfected patients undergoing diagnostic bronchoscopy were randomized into 2 groups of 10 patients: BAL was performed routinely in group R and with special precautions in group P. These precautions consisted of giving topical lidocaine by inhalation rather than by bolus injection, and passing the bronchoscope used for BAL through a previously inserted endotracheal tube. Quantitative culture of BAL specimens showed that 5 patients in group R (50%), but none of the patients in group P (0%), had at least 1 organism recovered in concentrations ≥10⁴ colony-forming units CFU/ml (p=0.016). Fifteen of 39 isolates (38.5%) in group R and none of 18 isolates in group P (0%) were present in concentration ≥10⁴ CFU/ml (p=0.001). We conclude that oropharyngeal contamination of BAL specimens can be minimized by adopting special precautions during the procedure and by using quantitative culture with 10⁴ CFU/ml as the cut-off point. This may increase the specificity of the technique in the diagnosis of lower respiratory tract infection without reducing its sensitivity.     

Pigment vs cholesterol cholelithiasis

Although pigment (calcium bilirubinate) gallstones in Japanese subjects are associated with bacterial infection, the role of infection in Americans with pigment gallstones has not been assessed. Anaerobic and aerobic cultures of gallbladder bile, stone, and wall were obtained at cholecystectomy from nine patients with pigment stones and 25 with cholesterol stones. Among pigment-stone subjects, only 1 of 9 grew organisms in greater than 10⁵ colony-forming units (CFU)/ml or g in gallbladder bile or wall. Likewise, growth greater than 10⁵ CFU/ml or g was present in only 1 of 26 biles and 2 of 26 walls from cholesterol-stone patients.Propionibacterium acnes was found in less than 10⁵ CFU/g or ml in at least 1 specimen from 6 of 9 pigment- and 12 of 26 cholesterol-stone patients. This organism was considered a contaminant because propionic acid concentrations in bile, an index of active bacterial metabolism, were similar in specimens with or without low-titer growth. The concentrations of bile salts, phospholipids, cholesterol, and bilirubin in gall-bladder bile was unaffected by the type of bacteria in low-titer growth. But the lipid concentrations were markedly depressed in two biles with bacterial growth greater than 10⁵ CFU/ml. The molar ratio of bile salts and phospholipids to cholesterol was significantly higher in biles surrounding pigment stones than those surrounding cholesterol stones (P<0.01). We conclude that significant bacterial infection (>10⁵ CFU/ml) is not associated with pigment or cholesterol stones in asymptomatic American subjects at cholecystectomy. These data suggest that pigment-stone formation in the United States is not primarily related to bacterial alteration of bile composition, as the experience with Japanese patients would suggest.Supported by NIH Grant AM-16549 and institutional funds of the Veterans Administration.Presented in part at the 77th Annual Meeting of the American Society for Microbiology, New Orleans, May 8–13, 1977.     

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria

Background Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion‐Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion‐Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods. Material and Methods Four Bacteria References (Staphylococcus epidermidis PEI‐B‐06, Streptococcus pyogenes PEI‐B‐20, Klebsiella pneumoniae PEI‐B‐08 and Escherichia coli PEI‐B‐19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation. Results Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19–1·32 × 10⁷ CFU/ml, S. pyogenes: 0·58–0·69 × 10⁷ CFU/ml, K. pneumoniae: 18·71–20·26 × 10⁷ CFU/ml and E. coli: 1·78–2·10 × 10⁷ CFU/ml. Conclusion The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low‐titre spiking of blood components, (ii) the property of donor‐independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion‐Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository.     

Aerobacteriology of laboratories and offices: Evidence of high risk exposure to immune complex formation in Nigeria

ObjectiveTo evaluate the air bacterial load especially in high environmentally polluted areas.MethodThe air bacterial load of 5 laboratories and 2 offices in Anambra State were sampled, using settled plate (sedimentation) method.ResultsAll the laboratories showed average of 44-55 colony forming units (CFU) within 15 minutes. Both aerobic and anaerobic bacteria were isolated. The predominant bacteria were: Micrococcus, Diptheroids, Staphylococcus species, Bacillus species, Corynebacterium diphtheriae (C. diphtheriae), Clostridium species and Propionibacterium amongst other variety of bacteria isolated. Office with air-conditioning system gave a total of 34 CFU out of 74 CFU shown in the two 2 offices, while the office without air-conditioning system gave forty (40) colonies.ConclusionIt was found that the laboratories with more number of people, with frequent movement were more air loaded with bacteria than those with less number of people. All the areas sampled, contain significantly high number of colony forming units (CFU) than 3 CFU found in standard clean room P <0.001. It is an evidence of high risk of persistent infections and subsequent immune complex formation.     

Inter-laboratory comparison of different rapid methods for the detection of bacterial contamination in platelet concentrates

Background Bacterial contamination of platelet concentrates still represents a major risk in transfusion medicine, and a variety of screening methods have been available to improve the safety of PCs. In the present study, the analytical quality of three different rapid screening methods (BactiFlow flow cytometry, Pan Genera Detection Assay, 23S rRNA RT‐PCR) was evaluated in an inter‐laboratory comparison in three different German blood services. Methods Samples were inoculated with different bacteria [Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli (two strains), Klebsiella pneumoniae (two strains), Enterobacter aerogenes (one strain), Serratia marcescens (one strain)] at different counts (4·5 × 10³–4·5 × 10⁸ CFU/ml) alternating with negative samples in one transfusion facility. Samples were blinded with a random order for each screening method, shipped to partners and analysed immediately after receipt with different rapid screening methods. Results The inter‐laboratory comparison revealed that the BactiFlow assay and 23S rRNA RT‐PCR‐screening detected all samples correctly (positive: 12/12, negative: 8/8). The Pan Genera Detection Assay test detected only four of the positive samples. Four of the non‐detected positive samples were below the assay’s detection limit. Another four inoculated samples with comparatively high bacteria counts were detected false negative (E. coli (two strains): 9·87 × 10⁵ and 2·10 × 10⁷ CFU/ml, respectively, K. pneumoniae: 4·79 × 10⁶ CFU/ml, S. aureus: 6·03 × 10⁵ CFU/ml). All rapid screening methods revealed no false‐positive results. Conclusions Both BactiFlow and 23S rRNA RT‐PCR demonstrated a high sensitivity to detecting bacterial contamination in PCs. The Pan Genera Detection Assay had some shortcomings regarding sensitivity, especially for the detection of Gram‐negative strains.     

Peroperative contamination and anastomotic leakage after resection for left colon stenosis

In this experimental study the effect of peroperative faecal soiling on immediate postoperative anastomotic leakage after resection and primary anastomosis of a left colon obstruction was evaluated. Faecal soiling was quantified by a standardized irrigation of the abdominal cavity and then culturing of the fluid. An increased peroperative soiling was found after resection of a stenosis compared to resection of a non-stenotic bowel. Anastomotic complications were correlated to the degree of bacterial contamination and a breakpoint of 10⁴ CFU/ml was found. Immediate postoperative leakage, tested with the bacteria Serratia marcescens, was not increased in the stenosis group. Thus, peroperative bacterial contamination seems to be one important factor in developing anastomotic complications after resection of colonic obstruction while an immediate leakage of bacteria through the anastomosis seems to be less important.     

Evaluation of a universal point‐of‐issue assay for bacterial detection in buffy coat platelet components

Bacterial contamination of platelet concentrates poses a major post‐transfusion infectious risk. This study was aimed at evaluating the efficacy of the BacTx ^® assay (Immunetics Inc.) for bacterial detection in leucocyte‐reduced buffy coat platelet pools and for its sensitivity in detecting clinical isolates, including bacteria that form surface‐attached aggregates (biofilm positives). Platelet pools were inoculated at bacterial concentrations of 0·8–13 CFU/ml. The BacTx ^® assay detected all species at concentrations ≥10³ CFU/ml within 20–69 h of platelet incubation. Detection of slow‐growing and biofilm‐forming strains was delayed in comparison with the other strains. This assay could be used as a point‐of‐issue method to increase the safety of the platelet supply.     

Microbiological Evaluation of the Efficacy of Soapy Water to Clean Hands: A Randomized,Non-Inferiority Field Trial

We conducted a randomized, non-inferiority field trial in urban Dhaka, Bangladesh among mothers to compare microbial efficacy of soapy water (30 g powdered detergent in 1.5 L water) with bar soap and water alone. Fieldworkers collected hand rinse samples before and after the following washing regimens: scrubbing with soapy water for 15 and 30 seconds; scrubbing with bar soap for 15 and 30 seconds; and scrubbing with water alone for 15 seconds. Soapy water and bar soap removed thermotolerant coliforms similarly after washing for 15 seconds (mean log₁₀ reduction = 0.7 colony-forming units [CFU], P < 0.001 for soapy water; mean log₁₀ reduction = 0.6 CFU, P = 0.001 for bar soap). Increasing scrubbing time to 30 seconds did not improve removal (P > 0.05). Scrubbing hands with water alone also reduced thermotolerant coliforms (mean log₁₀ reduction = 0.3 CFU, P = 0.046) but was less efficacious than scrubbing hands with soapy water. Soapy water is an inexpensive and microbiologically effective cleansing agent to improve handwashing among households with vulnerable children.     

Natural bioburden levels detected on rigid lumened medical devices before and after cleaning

Controversy exists concerning the degree of microbial contamination associated with the us of rigid lumened medical devices, the efficacy of standard cleaning techniques used to remove pathogenic microorganisms from lumen channels, and whether patients are placed at risk of cross infection because of microbial contamination. In this study the level and types of microorganisms found on rigid lumened medical devices before and after cleaning in a hospital environment were investigated. The bioburden level after clinical use was found to be relatively low, ranging from 10¹ to 10⁴ colony forming units (CFU) per device. After the instruments were cleaned, none of the devices studied contained bioburden levels greater than 10⁴ CFU and 83% had bioburden levels less than or equal to 10² CFU. The bioburden present before cleaning was comprised of organisms derived from the handling of the device, from the hospital environment, and from the patient. The bioburden present after cleaning was comprised of organisms typically derived from the handling of the device and from the hospital environment. The level of bioburden per device was also related to the anatomic site where the device was used, with lower numbers of organisms found on devices exposed to sterile body sites and the respiratory tract.     

Cardiac resynchronization improves microcirculation

BackgroundAlthough it is known that cardiac resynchronization therapy (CRT) in heart failure (HF) patients improves systemic circulation, its acute effects on microcirculation are as yet unknown. Therefore we investigated the sublingual microcirculatory changes in HF patients from CRT and right ventricular (RV) pacing by use of orthogonal polarization spectral (OPS) imaging.Methods and ResultsTwelve consecutive HF patients with a CRT device and 20 healthy individuals (HI) were included. Acute microcirculatory changes were assessed by functional capillary density (FCD) and capillary velocity (CV) measurement 6 months after CRT. FCD and CV were measured in HF patients sublingually after 15 minutes of programming 1 of 3 pacing modalities in random order (no pacing, RV pacing, and CRT). FCD was significantly higher in HI (11.2 ± 2.1 cm/cm²) compared with HF patients with RV pacing (8.9 ± 1.9 cm/cm²; P = .03) and no pacing (8.3 ± 2.4 cm/cm²; P = .02). CRT (12.1 ± 2.2 cm/cm²) significantly increased FCD in HF patients compared with RV pacing (8.9 ± 1.9 cm/cm²; P = .006) and no pacing (8.3 ± 2.4 cm/cm²; P = .008). CV was normal in all patients with or without pacing.ConclusionsCRT improves microcirculatory function as assessed by OPS imaging.     

Role of interleukin-8 in community-acquired pneumonia: Relation to microbial load and pulmonary function

Summary In pneumonia local phagocyte activation is crucial for clearing of pathogenic microorganisms. In this context alveolar macrophage interleukin-8 secretion, phagocyte oxidative response and concentrations of lavage proteins were quantified, including interleukin-8, in 31 patients with pneumonia, 13 age matched patients with peripheral lung consolidation and six healthy volunteers; these findings were related to the impairment of gas exchange and the bacterial load in the alveolar space. Increased interleukin-8 levels were found in bronchoalveolar lavage fluid (BALF) and in alveolar macrophage supernatants from patients with pneumonia (214 ng/10⁵ AM±121 vs 71 ng/10⁵ AM±35 and 66 ng/10⁵ AM±30, p<0.05). Interleukin-8 release from alveolar macrophages correlated with the upregulated spontaneous luminol enhanced oxidative response of pulmonary phagocytes but not with the neutrophil count in BALF. In pneumonia patients a significant difference was found between patients with 10⁴ or more colony forming units (CFU)/ml BALF of one pathogen and patients with less CFU or nonspecific microbiological results (261 ng/10⁵ AM±89 vs 179 ng/10⁵ AM±81 and 7.5 ng/ml BALF±17 vs 0.44 ng/ml BALF±1, p<0.05). Further, a negative correlation between interleukin-8 release of alveolar macrophages and the arterial pO₂ at the time of BALF could be demonstrated (r=–0.47, p<0.05). The results demonstrate local cellular activation in community-acquired pneumonia, which is related to the bacterial load in the alveolar space and to impairment of gas exchange. This is consistent with the hypothesis that pulmonary phagocytes play a central role in the pathogenesis of bacterial pneumonia, contributing not only to bacterial clearing but also to local tissue damage.     

Optimized Scansystem platelet kit for bacterial detection with enhanced sensitivity: detection within 24 h after spiking

BACKGROUND AND OBJECTIVES: The prevention and detection of bacterial contamination of platelet concentrates remains a major challenge for transfusion medicine. To be suitable for blood-transfusion services, the contamination detection method must be highly sensitive, easy to perform and preferably of low cost. In this spiking study, we evaluated the new optimized Scansystem Platelet Kit detection method for use on apheresis platelets. STUDY DESIGN AND METHODS: Apheresis platelet concentrates (APCs) were individually spiked with 10 colony-forming units (CFU)/ml of one of 10 different strains of bacteria. The spiked APCs were analysed at specific time-points during incubation by using the optimized Scansystem Platelet Kit. Bacterial enumeration was performed by plating onto blood agar. RESULTS: All the bacterial strains tested were detected by using the optimized Scansystem Platelet Kit when sampled 24 h after spiking. Compared to the Scansystem standard kit, sensitivity was increased to < 50 CFU/ml. The identity of the spiked bacteria was confirmed by Gram staining and DNA fingerprinting. CONCLUSION: The optimized Scansystem Platelet Kit was able to reliably detect, within 70 min, 10 transfusion-relevant bacterial species in APCs when a sample volume was taken 24 h after spiking. This is the first study carried out by using the optimized Scansystem bacterial detection that was found to have an enhanced sensitivity compared to the standard kit.     

Residual insecticidal activity of long‐lasting deltamethrin‐treated curtains after 1 year of household use for dengue control

Objective To evaluate the residual insecticidal activity of the PermaNet^® curtains on Aedes aegypti after 1 year of use in Thai households and to assess the influence of sun and dust exposure, washing practices and detergent use. Methods We sampled UV‐protected PermaNet^® curtains made of a long‐lasting deltamethrin‐[55 mg/m²] treated polyester netting, before (10 curtains) and after 8 (10 curtains) and 12 months (66 curtains) of household use in a field site in Chon Buri, Thailand. We assessed the residual insecticidal activity of the curtains by standard WHO bioassay, using a deltamethrin‐susceptible insectarium Aedes aegypti strain. Results Mosquito mortality was 100% before distribution, 100% at 8 months and 98.2% (95% CI 97.9–98.5) at 12 months of use. Sunlight, hand‐washing and detergent use had no effect on the residual insecticidal activity after 12 months. However, the mosquito survival rate increased by a factor of 6.4 (95% CI 3.5–11.8) on machine‐washed curtains and by a factor of 2.0 (95% CI 1.4–2.9) on curtains not covered by dust. Conclusion The residual insecticidal activity of PermaNet® curtains remains high after 12 months use under field conditions.