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Purpose: To determine the frequency and severity of ocular symptoms and signs in new orthokeratology (ortho-k) subjects using a povidone iodine (PI) disinfecting system compared to those present before lens wear, and whether these were associated with cleaning regimes., Methods: This study recruited 80 subjects from two myopia control studies, who used a PI disinfecting solution for routine use. Ocular symptoms and signs at baseline, one- and six-month after lens wear were reported via questionnaires and ocular examination, respectively. To determine if rates of occurrence were attributable to differences in cleaning regime, subjects were randomly assigned into four groups with respect to routine care procedures, which involved various combinations of rubbing and use of a daily and/or enzymatic cleaner., Results: Sixty-eight subjects completed all aspects of the study. As there were no significant differences in incidence of signs and symptoms between the four groups before and after lens wear (Friedman tests, p > 0.07), data were combined for further analysis. Prior to lens wear, itchiness (69 %) and dryness (53 %) were the most commonly reported symptoms. The frequency and severity of all symptoms remained similar after lens wear (p > 0.10). Presence of follicles in the lower tarsal conjunctiva (22 %) and conjunctival injection (15 %) was frequently observed, but reduced significantly after lens wear (p < 0.01). Mild corneal staining, noted in 13 % of subjects at baseline, did not change significantly over time (p = 0.17). Ocular signs were not necessarily reflected in symptoms and vice versa., Conclusion: Use of a PI-based solution did not increase the frequency or severity of ocular signs and symptoms observed before lens wear. Absence of a difference in occurrence of ocular discomfort with respect to cleaning regimes indicated that the use of the PI-based solution may adequately clean the lenses over a 6-month period., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: To determine organisms present in the conjunctiva of children before and after orthokeratology lens wear, using MALDI-TOF mass spectrometry., Methods: Conjunctival samples were collected from children aged 8-12 years (inclusive) at baseline and on three occasions over the first six months of orthokeratology treatment. All lenses were disinfected using the povidone iodine-based solution every day after use. Specimens were cultured and all isolated colonies were identified using MALDI-TOF mass spectrometry. Numbers of organisms and diversity were compared over the study period and the presence of any ocular pathogens noted and participants informed, where appropriate, to enhance their compliance with lens care routine., Results: Organisms isolated from 76 children were generally similar to other studies employing culture methods. However, MALDI-TOF results yielded a wider range of species of micrococci and corynebacteria , as well as a few less frequently reported organisms. Only one culture yielded fungi. Ocular pathogens were only isolated from 9 subjects (4 before lens wear and 5 after lens wear), each on one occasion only. Diversity and numbers of organisms fell slowly over the period of the study, but the changes were not significant., Conclusions: Lens wear did not affect the overall content of the ocular microbiome, but the diversity was somewhat reduced. The incidence of ocular pathogens was low, suggesting that risk of ocular infection was not substantially increased by orthokeratology treatment using a povidone-iodine disinfecting solution., (© 2022 The Authors.)

Purpose: To compare lens cleaning routines using a povidone iodine-based rigid lens disinfecting solution and its effect on conjunctival colonisation, and lens and lens case contamination., Methods: Participants, aged 6-10 years, receiving orthokeratology treatment were randomised to four lens cleaning routines: with and without the use of daily and/or weekly cleaners, which were performed by their parents. Conjunctival colonisation was compared before lens wear and at 1-, 3-, and 6-month after commencement of lens wear. Contamination of lenses and lens cases was investigated at these times. Organisms were identified using MALDI-TOF mass spectrometry., Results: Of the 76 participants who completed the study, conjunctival colonization was present in 24 (32 %) at baseline. Of the remaining 52 participants, 34 consistently yielded no growth. Participants positive at baseline were statistically more likely to be colonized after commencement of lens wear (p = 0.020). Overall, colonization rate was reduced to 15 % (11/72) after 6-month lens wear, which reached significance for initially colonized participants (p < 0.001). Few cultures yielded potential ocular pathogens, with notably no Pseudomonas aeruginosa. Contamination rates of both lenses and lens cases were also low, with few isolations of ocular pathogens. No significant differences were observed between cleaning regimes for conjunctival colonization or contamination of lenses or cases., Conclusions: Disinfection for rigid and ortho-k lens wearers may be effectively achieved with the use of povidone iodine-based solution, apparently regardless of cleaning routine adopted in the current study. The absence of pathogens in the conjunctiva, lenses, and lens cases in the great majority of samples indicates that it can improve the safety of overnight lens wear., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Aims: To compare the value of pre-treatment axial elongation (AE) and changes in refractive sphere (M change) for predicting the success in orthokeratology (ortho-k), in order to better identify suitable candidates for myopia control., Methods: This study further analysed the data of 66 subjects receiving 7-month ortho-k treatment, following a 7-month observation period, during which single-vision spectacles were worn. Rate of myopia progression was determined by AE and M change and subjects categorised as slow, moderate, or rapid progressors based on these changes. Outcomes of myopia control, based on the AE reduction after ortho-k, were classified as 'ineffectual', 'clinically insignificant', or 'beneficial'., Results: Of the 20 subjects, initially categorised as slow by AE and, of whom 95% were similarly categorised by M change, none benefitted from ortho-k. In contrast, of the 22 subjects with moderate AE, 77% and 23% displaying slow and moderate M change, respectively, the majority (73%) benefitted from ortho-k lens wear. The 24 subjects with rapid AE were poorly identified by M change, with only 21% correctly categorised. The vast majority of rapid progressors showed significant benefit after ortho-k., Conclusion: Progression of AE is a good indicator of subsequent success of ortho-k treatment. Delaying commencement of therapy is prudent for children with slow progression as results indicate that they would be unlikely to benefit from this intervention. As change in refractive error frequently underestimates rapid progression of AE, its value for identifying appropriate candidates for myopia control is poor., Competing Interests: This study was sponsored by a Collaborative Research Agreements between PolyU and Menicon Co. Ltd, Japan (Pauline Cho; ZG50, ZG7X) (http://www.menicon.com). The sponsors had no role in study design, data collection and analysis, decision to publish, or preparation of this manuscript, and funding from the the industry does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: Previous decades have witnessed a change in the epidemiology of Clostridium difficile infections. This study aimed to determine temporal trends in the incidence of C difficile infection across geographic regions., Methods: An initial search of the relevant literature was conducted from date inception to October 2018 without language restriction. We estimated the pooled incidences using logit transformation, weighted by inverse variance. The Joinpoint Regression Analysis Program was used to explore its temporal trend., Results: Globally, the estimated incidence of C difficile infection increased from 6.60 per 10,000 patient-days in 1997 to 13.8 per 10,000 patient-days in 2004. Thereafter, a significant downward trend was observed, at -8.75% annually until 2015. From 2005 to 2015, the incidences in most European countries decreased at a rate between 1.97% and 4.11% per annum, except in France, where an increasing incidence was observed (β = 0.16; P < .001). The incidences have stabilized in North America over the same period; however, in Asia, the incidence increased significantly from 2006 to 2014 (annualized percentage change = 14.4%; P < .001). The increase was greatest in Western Asian countries, including Turkey and Israel (β > 0.10; P < .004)., Conclusions: This study revealed rapid changes in the incidence of C difficile infection. This meta-analysis should inform the allocation of resources for controlling C difficile infection and future surveillance efforts in countries where epidemiologic information on C difficile infection remains sparse., (Copyright © 2019 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

Proper drying of hands after washing is an integral part of hand hygiene. An experimental study on 30 subjects using multiple comparisons of six hand drying methods including 1) drying on own clothes, 2) drying with one paper towel, 3) drying with two paper towels, 4) drying with a warm air dryer while holding hands stationary for 20 s, 5) drying with a warm air dryer while hand rubbing for 20 s, and 6) drying with a jet air dryer until complete dryness was achieved. It aimed to determine the effectiveness of different hand drying methods for removing bacteria from washed hands, so as to identify the optimum method using minimum resources. Our study demonstrated that the use of jet air dryers is the best method to eliminate bacteria on hands, whereas drying hands on one's own clothes is the least effective. Drying hands in a stationary position could remove more bacteria than rubbing hands when using a warm air dryer for 20 s, which mimics people's usual hand-drying practice. No significant difference in bacteria reduction was detected between the use of one or two paper towels for hand drying; therefore, using fewer resources is recommended to maintain environmental sustainability.

Purpose: The presence of biofilm in the lens case has been shown to be a risk factor for contamination of lenses and consequently microbial keratitis. This study aimed to evaluate effectiveness of solutions for rigid contact lenses in prevention and disruption of biofilm in lens cases and methods for biofilm detection., Method: This study adopted a stepwise approach to evaluate effectiveness of four rigid lens disinfecting solutions against biofilm. These included two polyhexamethylene bigiuanide (PHMB) solutions and a chlorhexidine/PHMB-based solution, as well as a novel povidone-iodine formulation. The presence of biofilm following exposure to the solutions was assessed using both crystal violet (CV) staining and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) viability assay, taking into account the effect of lens case design. Three lens case designs, conventional flat, large bucket type, and cylindrical cases, were investigated for the ability to trap stain and allow biofilm formation., Results: Considerable differences were noted between solutions in their ability to prevent and disrupt biofilm (p < 0.001). Lens case design greatly influenced optical density (OD) measurements even in negative controls, as cylindrical cases trapped more stain, increasing OD readings. Correcting for this factor reduced variations, but could not differentiate between residues and biofilm. MTT assay revealed that both povidone-iodine and chlorhexidine-containing solutions could effectively kill > 95% of organisms, whilst PHMB-based solutions were less effective with up to 55% of staphylococci and 41% of Pseudomonas surviving at 24 h., Conclusion: Biofilm can rapidly form in lens cases and may not be killed by disinfecting solutions. Of the solutions tested, none were able to prevent biofilm formation or disrupt established biofilm, but those containing chlorhexidine or povidone iodine were able to penetrate the biofilm and kill organisms. Assessment of biofilm by CV assay may be confounded by lens case design. Whilst CV assay can demonstrate presence of biofilm, this technique should be accompanied by viability assay to determine bactericidal activity., (© 2019 The Authors Ophthalmic & Physiological Optics © 2019 The College of Optometrists.)

Purpose: This study aimed to develop evidence-based guidelines for identifying suitable subjects for myopia control using orthokeratology (ortho-k)., Methods: Changes in axial elongation (AE) in the worse eyes of 66 myopic children (myopia between -0.75 and -4.50 D and astigmatism <2.00D, and aged 6 to <16 years old) who wore single-vision spectacles for seven months before switching to orthokeratology treatment for another seven months were observed., Results: AE during ortho-k lens wear was affected by age and rate of progression during spectacle wear. The percentage of subjects with rapid, moderate, and slow AE (equivalent annual myopia progression; rapid: ≥1.00D; moderate: 0.50D to <1.00D; slow: <0.50D) during spectacle wear was 36.3%, 33.3% and 30.3%, respectively. Rapid progression was most common in subjects aged less than nine, but 25% of subjects aged 9 to <13 and 12.5% aged 13 to <16 also demonstrated rapid progression. All subjects with rapid AE during spectacle wear achieved a significant reduction in eye elongation with ortho-k lens wear. Guidelines for patient selection was proposed based on the initial age and history of myopia progression., Conclusions: Myopia control is indicated for children at risk of developing high myopia. The suggested guidelines can help practitioners to identify children for whom the benefits outweigh the risks of serious adverse events., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

This study investigated the efficacy of a novel povidone-iodine based disinfection solution for rigid gas permeable (RGP) lenses compared to three other currently available multipurpose and hydrogen peroxide solutions. Bactericidal and fungicidal activities were assessed using ISO 14729 reference methods, whilst amoebicidal properties were evaluated using an automated viability counter. All solutions were also assessed for long term storage stability over a 3-month period. The FDA guidelines were adequately achieved by all solutions tested and 3-month storage did not affect their activity against bacterial and fungal agents. Activity against Acanthamoeba castellani trophozoites reached 1-log reduction for the povidone-iodine solution and approached this level for the remaining solutions. Activity against cysts was somewhat reduced and ranged from 78 to 86% reduction in viability. A povidone-iodine based solution, which may offer advantages as resistance to this agent has not been demonstrated and it lacks toxicity, provided equivalent antimicrobial activity to other RGP solutions., (Copyright © 2018. Published by Elsevier Ltd.)

Background: The adequate fit of an N95 respirator is important for health care workers to reduce the transmission of airborne infectious diseases in the clinical setting. This study aimed to evaluate whether adequately sealed N95 respirators may provide consistent protection for the wearer while performing nursing procedures., Methods: Participants were a group of nursing students (N = 120). The best fitting respirator for these participants was identified from the 3 common models, 1860, 1860S, and 1870+ (3M), using the quantitative fit test (QNFT) method. Participants performed nursing procedures for 10-minute periods while wearing a backpack containing the portable aerosol spectrometers throughout the assessment to detect air particles inside the respirator., Results: The average fit factor of the best fitting respirator worn by the participants dropped significantly after nursing procedures (184.85 vs 134.71) as detected by the QNFT. In addition, significant differences in particle concentration of different sizes (>0.3, >0.4, >1.0, and >4.0 µm) inside the respirator were detected by the portable aerosol spectrometers before, during, and after nursing procedures., Conclusions: Body movements during nursing procedures may increase the risk of face seal leakage. Further research, including the development of prototype devices for better respirator fit, is necessary to improve respiratory protection of users., (Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

Tick-borne disease in dogs is common in South-east Asia and includes babesiosis and ehrlichiosis. These diseases can be largely prevented by compliant use of tick preventive products. This study investigated knowledge of ticks and tick-borne disease and use of tick preventive agents by a large sample of dog owners in Hong Kong. A total of 492 valid questionnaires were completed by owners attending veterinary practices, approached by researchers at common dog-walking areas, or targeted via local social media sites for pet owners. A high proportion of respondents were aware of tick-borne disease (79%) and this correlated well with use of preventive products. However, 18% of owners did not use any protection, mainly due to lack of knowledge of the risk of disease. Targeted advice stressing the importance of tick protection use and frequent follow-up at veterinary clinics could help reduce the risk of tick-borne disease. It would be beneficial if veterinarians provided training of frontline staff at the clinics to ensure they provide essential information to clients in an easily understandable format., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Purpose: Acanthamoeba keratitis (AK), which is associated with noncompliant use of contact lenses, remains difficult to treat due to delayed diagnosis and paucity of therapeutic agents. Although improvements in activity against Acanthamoeba infection have been achieved in disinfecting solutions for soft contact lenses, such modifications have not been extended to those for special rigid gas permeable (RGP) contact lenses, which are increasingly used for myopia control in children. Phytochemicals present in herbs used for traditional Chinese medicine may be effective as therapeutic or preventive agents. The purpose of this study was to investigate amoebicidal properties of lead phytochemicals of Radix scutellariae alone and in combination with multipurpose (disinfecting) solutions (MPS) for RGP lenses., Methods: Viability of Acanthamoeba castellani and A. polyphaga trophozoites was determined following exposure to four phytochemicals: baicalin, baicalein, wogonoside, and oroxylin A and both alone and in combination with four RGP MPS, using a modified stand-alone technique., Results: As individual agents, wogonoside and oroxylin A showed highest activity against A. castellani and A. polyphaga trophozoites, respectively. For both organisms, the combination of baicalein and oroxylin A was superior. Effectiveness of MPS alone did not exceed 0.27 log reduction, but addition of combined baicalein and oroxylin A resulted in 0.92 and 0.64 log reductions of A. castellani and A. polyphaga, respectively., Conclusions: The combination of baicalein and oroxylin A enhanced the activity of MPS for RGP contact lenses against trophozoites of two pathogens, A. castellani, and A. polyphaga, and offers a potential therapeutic and/or preventative agent for AK.

Background/aim: There has been increasing evidence of the emergence of antiseptic resistance mediated by quaternary ammonium compound (QAC) resistance genes, which may reduce the efficacy of disinfection. Although the presence of QAC-positive staphylococci has been shown to be elevated in contact lens wearers, the efficacy of multipurpose solutions (MPS) against such isolates has not been determined. This study investigated the efficacy of four MPS for rigid gas permeable (RGP) lenses against staphylococci-harbouring QAC genes., Methods: Ability to reduce viability by three or more log reductions of four MPS for RGP lenses was tested against 60 disinfectant-resistant gene-positive staphylococci, comprising 38 coagulase-negative staphylococci (CNS) (17 ITALIC! qacA/B, 7 ITALIC! smr, 5 ITALIC! qacH, 9 habouring two or more genes) and 22 ITALIC! Staphylococcus aureus (16 ITALIC! qacA/B, 4 ITALIC! smr, 2 ITALIC! qacA/B+ ITALIC! smr)). 60 gene-negative isolates of staphylococci (30 CNS and 30 ITALIC! S aureus) were used as controls. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these four MPS were determined., Results: Although there was some variation between solutions, all failed to achieve a 3-log reduction in some ITALIC! S aureus and CNS isolates. Strains harbouring disinfectant-resistant genes were significantly less likely to be reduced by 3 logs by three of the solutions. Overall, the MIC and MBC of the four MPS against gene-positive clinical isolates were significantly higher than those of gene-negative isolates., Conclusion: The efficacy of MPS solutions for RGP lenses against staphylococci varied. The presence of disinfectant-resistance genes significantly adversely affected disinfecting capacity of RGP solutions., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

We aimed to identify the source of Staphylococcus aureus contaminating hands of food handlers. Nasal samples and direct fingertip imprints were collected on 2 occasions from food handlers and characterized to determine likely sources of hand contamination. Most hand contamination was attributable to nasal isolates of persistently colonized coworkers who had presumably contaminated the environment. Regular handwashing should be supplemented by effective environmental disinfection., (Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

This study aimed to investigate the presence of vancomycin-non-susceptible subpopulations in apparently susceptible meticillin-resistant Staphylococcus aureus (MRSA) and the ability of these isolates to develop into homogeneously resistant strains. Vancomycin MICs of 200 clinical MRSA isolates were determined using agar dilution (AD) and spiral gradient endpoint (SGE) technique. Isolates with an MIC≤2mg/L but displaying subpopulations with an MIC>2mg/L by SGE were re-tested by Etest and PAP-AUC and were incubated with 2mg/L vancomycin for 2 weeks. MIC testing was repeated weekly by AD, Etest and SGE to observe progression to non-susceptibility. A total of 17.5% and 16.0% of isolates were non-susceptible to vancomycin (MIC>2mg/L) by SGE and AD, respectively. Eight isolates (4%) displayed a resistant subpopulation; five met the definition of hVISA by PAP-AUC. The initial Etest MIC for these isolates was 2mg/L, but resistant subpopulations were observed in only three isolates on prolonged incubation. MICs of all eight isolates increased rapidly in the presence of vancomycin, reaching ≥3.0mg/L by Day 7 and ≥4mg/L after 14 days by all three methods. The prevalence of vancomycin-non-susceptible MRSA was high, and non-susceptibility developed rapidly in seemingly susceptible isolates with covert subpopulations. These were effectively detected by SGE. With increasing reports of vancomycin clinical failure, early detection of potentially non-susceptible isolates before or early in vancomycin therapy is essential to avoid further resistance development and poor clinical outcomes. SGE offers a novel and cost-effective technique for detection of potentially non-susceptible strains., (Copyright © 2015 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

Chinese roasted pork has been implicated as a major source of food poisoning caused by Staphylococcus aureus. Establishing the source, either as contaminants from raw meat or from food handlers, could facilitate drafting more appropriate guidelines for better prevention of food poisoning. To determine the rate and source of staphylococcal contamination, roasted pork purchased from 50 sui-mei shops in Hong Kong was sampled for presence of S. aureus by enrichment and subsequent culture. Isolates were characterized for methicillin sensitivity, spa type, and presence of Panton-Valentine leukocidin (PVL) and staphylococcal enterotoxins (SEs). Methicillin-resistant isolates were confirmed by presence of mecA and SCCmec type and sensitivity to vancomycin investigated. S. aureus was isolated from 25 (50%) samples, with 3 yielding two colony types. Of the 28 isolates, 3 were resistant to cefoxitin, but only 2 were mecA positive and belonged to SCCmec type V. The mecA negative isolate also lacked mecC, but had a penicillin minimum inhibitory concentration of 10 mg/L. A livestock-associated spa type (t034) was only observed in one methicillin-sensitive strain, all other isolates appearing to be of human origin, with 30% belonging to t189. One isolate was PVL positive and five carried genes for classical SEs. The high rate of staphylococcal contamination observed was probably associated with food handlers, as the strains belonged to spa types previously reported in clinical and nasal carriage isolates. The presence of enterotoxins in 18% of isolates confirms the risk of food poisoning associated with this product and emphasizes the need for improved guidelines for handling after preparation. Use of refrigerated display areas should be considered.

We report the use of gold nanoparticles (Au NPs) for direct colourimetric polymerase chain reaction (PCR) detection of methicillin-resistant Staphylococcus aureus (MRSA) in clinical specimens. The colourimetric assay comprised of 2 Au NP probes functionalized with Staphylococcus aureus 23S rRNA- and mecA-specific oligonucleotides. In this study, 72 clinical samples were tested, which included positive blood culture (n=23), urine (n=8), respiratory samples (n=23), as well as wound swabs, pus and body fluid (n=18). Results were recorded qualitatively by direct visual examination and quantitatively by UV-vis spectrophotometry. Using conventional bacterial culture as the gold standard, the sensitivity, specificity, positive predictive value and negative predictive value of this colourimetric assay were 97.14%, 91.89%, 91.89% and 97.14%, respectively, which were comparable to that of commercial real-time PCR assays with a lower cost per reaction. Our assay also showed good agreement with bacterial culture (κ=0.889). The overall detection limit was 500 ng target amplicon, which was comparable to or better than other similar Au NP biosensors. Interestingly, our data revealed the possible relationship between Au NP probe-target hybridization site and assay performance, which might provide hints for design of the Au NP biosensors for nucleic acid detection. To conclude, our study was the first report on the use of Au NP colourimetric assay for direct detection of MRSA in various types of clinical specimens. Further evaluation of the assay is needed in large-scale trials which can also allow for some modifications to streamline the procedures for routine use., (© 2013 Elsevier B.V. All rights reserved.)

Purpose: Acinetobacter has low virulence but causes infections in subjects with reduced immunity. It has been reported in ocular infections including those of patients using contact lenses. Treatment is difficult because Acinetobacter is frequently multidrug resistant. Antibiotic-resistant strains frequently also harbor genes for antiseptic resistance (quaternary ammonium compound [QAC]) genes. Because Acinetobacter is part of the normal flora, it may contaminate contact lens and accessories. This study aims to investigate carriage rates of QAC genes in household and clinical isolates of Acinetobacter and to determine the effectiveness of two multipurpose solutions (MPSs) for soft lenses against organisms carrying QAC genes., Methods: DNA was extracted from 11 bathroom isolates and 15 clinical isolates and amplified by polymerase chain reaction to determine the presence of qacEΔ1. Gene-positive and gene-negative control strains were used to challenge the two MPSs, and minimum inhibitory concentrations (MICs) of these organisms to benzalkonium chloride and chlorhexidine gluconate were determined., Results: More than 90% of isolates carried qacEΔ1. The MICs of clinical isolates were higher than those of isolates of bathrooms. Both MPSs were able to produce a 3-log reduction in the numbers of all isolates., Conclusions: Although most isolates carried qacEΔ1 and elevated MICs to benzalkonium chloride and chlorhexidine gluconate were observed, all were susceptible to both MPSs tested. However, if there were to be poor compliance with care procedures, it is probable that such organisms could survive in the presence of diluted or expired solutions.

Staphylococcus aureus contaminating raw meat may increase nasal colonization risk for occupationally-exposed food handlers. Food handlers from six catering establishments were nasally sampled for S. aureus and completed a questionnaire on carriage risk factors. Isolates were characterized for antibiotic susceptibility, spa type and, for methicillin-resistant strains, SCCmec type. Of 434 food handlers, 99 (22.8%) were colonized with S. aureus. Five isolates were methicillin-resistant belonging to SCCmec IV (2) and V (3). Resistance to tetracycline (20%), and erythromycin (16%) was high, but <10% to other antibiotics. Spa typing revealed 17% of isolates as t189, with 8% each t127 and t1081. Food handlers ever handling raw meat had a significantly higher colonization risk (OR=2.7; 95% CI: 1.7-4.5), increasing to 3.7 (95% CI: 2.0-6.8) for those always exposed. This is the first report of increased colonization risk in food handlers exposed to raw meat. This occupational hazard may increase infection risk, so improved compliance with workplace hygiene may be required., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Porcine strains of livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) have been recognized in many countries and have been shown to be able to cause human infection. Resistance to non-beta lactam antibiotics has been reported but non-susceptibility to vancomycin, which is known to occur in human MRSA, has so far not been observed in LA-MRSA. Such resistance is typically fairly low level involving changes in the cell wall thickness. The development of resistance is usually preceded by presence of a sub-population having an increased MIC, which is selected for by exposure to vancomycin. This study investigated vancomycin susceptibility of one hundred porcine MRSA isolates using three MIC methods including spiral gradient endpoint (SGE) technique which allows visualization of more resistant sub-populations. SGE revealed 16 strains with an MIC above 2.0 mg/L, of which 14 were determined to have MIC 4 mg/L by agar dilution (AD). SGE revealed a further two isolates with MIC < 2 mg/L had a sub-population >2 mg/L. In addition, trailing endpoints not reaching resistance were present in 26 isolates with MIC < 2 mg/L. Sequencing of the genes of the VraSR/GraSR two component systems of ten of the resistant strains for comparison with susceptible strains revealed changes, including the presence of stop codons, in vraS and graR, but these were not consistent in all isolates. Other genetic changes may contribute to vancomycin non-susceptibility and require investigation. As failure to respond to treatment has been reported in clinical isolates with MIC > 1.5 mg/L, the presence of vancomycin non-susceptibility in porcine isolates is of concern and further monitoring of LA-MRSA is essential.

Purpose: Reports on cytotoxic effects of rigid gas-permeable lens multipurpose solutions, which remain important because of increasing popularity of orthokeratology, are limited. This study determined cytotoxic effects of rigid gas-permeable lens multipurpose solutions on human corneal epithelial cells and assessed the proliferation rate at different levels of cell membrane damage., Methods: The human corneal epithelial cells were exposed to multipurpose solutions containing chlorhexidine gluconate (0.003%) and polyaminopropyl biguanide (PHMB) (0.0005%) (MPS-A), PHMB (0.0005%) (MPS-B) and PHMB (0.0001%) (MPS-C) for one, five and 10 minutes. Following staining with Annexin V-FITC/7-AAD, cell viability and membrane integrity were assessed by flow cytometry. Effects of exposure to concentrations of 10 to 40 per cent multipurpose solutions for 12 hours on the metabolic rate of human corneal epithelial cells were assessed by 3-(4-,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell proliferation assay. Recovery rates were assessed after re-culture for 96 hours at 37°C., Results: MPS-A exposure caused the highest percentage of early and late necrotic cells for all exposure times and was significantly higher than other multipurpose solutions (p < 0.0001). After 10 minutes exposure, almost 40 per cent of cells in MPS-A but less than five per cent in MPS-B or MPS-C, were in late necrotic stage. After 12 hours of exposure, cell activity was significantly reduced in a dose-response manner for MPS-A treated cells only (p > 0.05). After 96 hours of re-culture, all exposed cells showed some reduction in viability but the effects of exposure to 30 and 40 per cent MPS-A resulted in loss of viability., Conclusion: The presence of chlorhexidine appeared to increase cytotoxicity of multipurpose solutions for rigid gas-permeable lenses. This was apparent in both increased levels of necrotic cells on initial exposure and reductions in viability after prolonged exposures at lower dilutions. Multipurpose solutions containing PHMB as a preservative, while not causing acute cytotoxicity, did affect cell viability following exposure to diluted solutions. This indicated it is inadvisable to expose the cornea to multipurpose solutions but rather to rinse lenses with saline before insertion and use artificial tears for rewetting., (© 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.)

Objectives: The presence of methicillin-resistant Staphylococcus aureus (MRSA) on meat purchased from retail outlets may allow its spread to households and represents a risk for colonization and possibly infection of consumers. Improved isolation methods have indicated that more than 10% of samples are positive. We aimed to determine rates of MRSA contamination of meat samples, including comparison of fresh and frozen samples. We characterized isolates and determined their antibiotic susceptibility., Methods: Samples of raw meats commonly consumed in Hong Kong were investigated for MRSA contamination using a double-enrichment isolation method. Isolates were characterized by antibiotic susceptibility testing, presence of mecA, SCCmec type, staphylococcal enterotoxins, Panton-Valentin leukocidin (PVL), and spa type. Differences in rates of MRSA contamination between meat types, rearing method, locations, sources, and fresh or frozen storage were compared., Results: MRSA was recovered from 21.9% of pork samples (78/355), 6.8% chicken (31/455), and 4.4% of beef (17/380). Isolation was considerably higher from fresh pork (47%) than frozen (0.6%), whereas contamination rates in fresh (6%) and frozen (7%) chicken were similar. All strains were multidrug resistant. All contaminated fresh pork and most frozen chicken originated from China. Most isolates belonged to CC9, being SCCmec IVb and spa type t899 or closely related spa types, but one chicken sample yielded ST398. Five strains carried spa types associated with human isolates. The egc enterotoxin group was present in the majority of isolates, but PVL in only three from chicken., Conclusions: The predominance of t899 in isolates indicates that the primary source of contamination may be pig carcasses, previously demonstrated to frequently harbor CC9-positive MRSA in Hong Kong and China. The high rates of meat contamination suggest that improvements in food safety and personal hygiene guidelines may be advisable to reduce risk of spread of these MRSA strains in the community.

Aim: This study aimed to assess the molecular subtypes of breast cancer for patients attending a dedicated breast care center and examine the association with clinicopathological features, treatment and survival outcomes., Methods: Demographic, clinicopathological and treatment details were collected from women with primary breast cancer. Immunohistochemical subtypes were also collected. The association between breast cancer subtypes and clinicopathological features was assessed using the chi-square or Fisher's exact test. Survival outcomes were compared among subtypes with the log-rank test., Results: Immunohistochemical subtypes were not associated with tumor size, lymphovascular invasion or lymph node involvement but differed by histological grade (p=0.014) and nuclear grade of tumors (p=0.001). The 5-year overall survival estimates for luminal A, luminal B, HER-2-positive and triple-negative tumors were 100%, 96.2%, 71.4% and 92.3% respectively. Compared to luminal A tumors (93.4%), luminal B (80.8%), HER-2-positive (71.4%) and triple-negative (76.9%) tumors exhibited a reduced disease-free survival (DFS). Patients with ER-positive tumors had a higher DFS than their ER-negative counterparts (p=0.036). Patients with tumors expressing a low Ki-67 level had a more favorable prognosis (p=0.02)., Conclusions: The most prevalent luminal A subtype is associated with relatively better prognosis, whereas HER-2-positive and triple-negative tumors are prone to early relapse with diminished survival.

As the literature has described the increasing penetration of DDSL into the contact lens market worldwide, this review aimed to describe the development of this modality as a solution to the problems experienced with other types of contact lenses. The advantages of DDSL in comparison to reusable lenses are discussed. The important role of the practitioner in prescribing for and managing patients using this lens type are also examined, in particular with respect to non-compliance. Problems with the use of this lens type and possible solutions are explored and new applications and future development in this field are described., (Copyright © 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Objectives: Problems of vancomycin non-susceptible Staphylococcus aureus (VISA) and subsequent treatment failure are increasing. This study aimed to observe development and loss of vancomycin non-susceptibility, determine exposure time needed for resistance development, and follow mutations in the VraSR and GraSR two-component systems during these processes., Methods: Sequences of vraS, graR and rpoB, proposed as critical sites of mutation associated with non-susceptibility development, were compared in susceptible clinical methicillin-resistant S. aureus isolates both initially and following vancomycin induction and its withdrawal, to identify mutations. Mutations were correlated with exposure time, increase in vancomycin MIC and phenotypic changes., Results: Both time required for heterogeneous VISA and VISA development, and maximum MIC attained (6-20 mg/L) varied between strains. Sequence analysis revealed the presence of stop codons in an initial strain with delayed non-susceptibility development. Other changes in vraS and graR occurred during VISA development in all isolates. After removal of vancomycin pressure, most strains reverted to susceptibility accompanied by emergence of stop codons in both vraS and graR. One strain not displaying stop codons remained resistant in the absence of vancomycin pressure. A substitution in GraR (D148Q) appeared to be associated with an elevated MIC (20 mg/L). No rpoB mutations were observed throughout VISA development., Conclusions: Vancomycin non-susceptibility developed in all strains tested. Mutations in vraS and graR appeared to be essential for VISA development, with stop codons playing an important role in delaying non-susceptibility development and reversion. Absence of mutations in rpoB suggests that these are not essential for vancomycin resistance. Further work is required to confirm consistent changes involved in non-susceptibility development.

Background: Inadequate infection control knowledge about enteral feeding (EF) practices among nursing home staff may lead to contamination of EF systems., Aim: To investigate the effectiveness of an infection control programme (ICP) on knowledge and practice of EF of nursing home staff, and to explore the correlation between the ICP and bacterial contamination of the hands of staff and feeding equipment., Methods: Using a quasi-experimental pre-post-test control design, each intervention and control group consisted of 15 residents and 10 staff. EF knowledge and practice were assessed by questionnaire and observation. The intervention group received an ICP. Samples were collected from the hands of staff, enteral feed, flow regulators, feeding tube hubs, and the nasopharynx and gastric fluid of residents, and analysed for total bacterial counts and presence of meticillin-resistant Staphylococcus aureus (MRSA) before and after the ICP., Findings: The intervention group showed a significant improvement in knowledge and practice after the ICP (P < 0.05). Pretest samples from the hands of staff, tube hubs, and the nasopharynx and gastric fluid of residents were contaminated with >10(4) colony-forming units/mL. Contamination was significantly lower in the post-test samples of the intervention group (P < 0.05), and remained unchanged in the control group. The mean (± standard deviation) number of MRSA-positive samples decreased from 2.1 ± 1.6 to 0.4 ± 0.7 (P < 0.05) in the intervention group. MRSA hand contamination was highly correlated with contamination of regulators, gastric fluid, tube hubs and enteral feed (P < 0.05), illustrating the close relationship between contaminated feed and poor hand hygiene., Conclusion: An effective ICP can significantly reduce the contamination of enteral feed. The provision of ICPs is strongly recommended in nursing homes., (Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

Environmental staphylococcal contamination was investigated by culture of 400 automated teller machines (ATMs). Isolates were characterized for antibiotic and antiseptic susceptibility, carriage of antiseptic resistance genes (QAC genes), and spa types. MRSA, which was similar to local clinical isolates, was present on two (0·5%) of the 62 (15·5%) ATMs that yielded Staphylococcus aureus. QAC genes were more common in coagulase-negative staphylococci (qacA/B 26·0%, smr 14%) than S. aureus (11·3% qacA/B, 1·6% smr). QAC-positive isolates had significantly higher minimum inhibitory concentrations/minimum bactericidal concentrations to benzalkonium chloride and chlorhexidine digluconate. QAC gene presence was significantly associated with methicillin and tetracycline resistance. Survival of staphylococci, including MRSA, on common access sites may be facilitated by low disinfectant concentrations, which select for disinfectant-tolerant strains, while co-selecting for antibiotic-resistance determinants. Disinfection procedures should be performed correctly to help prevent spread of resistant pathogens from reservoirs in the community.

Purpose: To compare the rates of bacterial contamination in cylindrical and flat contact lens cases of orthokeratology (ortho-k) users and to investigate their preference of lens case design based on ease of use and handling., Methods: Twenty-four children receiving ortho-k treatment were recruited. Each subject was given one cylindrical and one flat lens case, of which one side (50% right, 50% left) was sealed to prevent usage. Subjects were instructed to either rinse the case with water and air dry or rinse with multipurpose solution (MPS) and refill with MPS for storage after lens removal. After 1 month, cases were collected for culture, which was performed on the screw top, inner surface of cases, and also the holder for cylindrical cases. Each subject/parent completed a questionnaire about preference of case design., Results: No significant differences in rates of surfaces contaminated were found between cleaning methods. Overall, 30% of both inner surfaces and screw tops of the cases yielded potentially pathogenic organisms, with significantly higher numbers present on both the inner surfaces (p = 0.003) and the screw tops of the flat cases (p = 0.001). Contamination of the inner surfaces with only normal flora occurred exclusively in the flat cases, but the screw tops of both case types frequently yielded only normal flora. Cylindrical case holder contamination was similar to the inner surface. There was a strong preference (75%) for the cylindrical cases, with subjects/parents citing ease of use and cleaning, good appearance and transparency, and reduced amount of MPS used., Conclusions: Although correct lens case care remains the most important factor in reducing contamination of the case, use of the cylindrical case design, preferred by the majority of subjects/parents, significantly reduced contamination in ortho-k subjects. The method used for cleaning the lens case had no effect on the rates of contamination in this study.

Purpose: The aim was to determine the cytotoxic effects of three multipurpose solutions (MPS) on human corneal epithelial cells (HCEC) and to assess the metabolic rates of recovering cells at different levels of cell membrane damage., Method: The effects of one to 15 minutes exposure to multipurpose solutions containing polyquaternium-1 (MPS-A), polyaminopropyl biguanide (MPS-B) and polyhexanide (MPS-C) on HCEC were determined. Recovery rates at different levels of cell membrane damage were assessed after re-culture for two hours at 37°C. Cell viability and membrane integrity were assessed using Annexin V-FITC/7-AAD staining and flow cytometry. Effects of concentrations of 10 to 40 per cent multipurpose solutions on the metabolic rate of recovering HCEC were assessed using a Vybrant MTT cell proliferation assay kit., Results: The highest percentage of late necrotic cells resulted after exposure to MPS-A compared with other solutions and the control (p < 0.001). The percentages of early necrotic cells after 10 and 15 minutes of soaking in MPS-B were significantly higher than the control and other multipurpose solutions (p < 0.001). Although MPS-C exposure also resulted in statistically significant higher percentages of early necrotic cells than the control (p < 0.005), these differences were small. No recovery was noted when HCEC treated with multipurpose solutions were re-cultured, with numbers of dead cells in MPS-B-treated cultures increasing fourfold. The MTT assay showed significant dose-response decreases of 500 nm absorbance for all MPS-treated cells. In 40 per cent MPS-A-treated HCEC, lack of activity indicated the cells were non-viable., Conclusions: Multipurpose solutions induced varying levels of irreversible tissue sensitivity reactions, with MPS-A showing the greatest effects. The solutions damaged cell integrity and reduced metabolic rates suggesting delayed healing ability. The formulations of multipurpose solutions need to balance antimicrobial effectiveness with low cytotoxicity, which might not be currently possible to achieve. In light of our results, we suggest that contact lens wearers should be advised to rinse the soaked lenses with saline before lens insertion., (© 2012 The Authors. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.)

Purpose: To compare the traditional manual hemacytometer method and an automated counter (Vi-cell) to enumerate and distinguish between viable and non-viable amoeba, and to determine the efficacies of contact lens (CL) disinfecting solutions against three species of Acanthamoeba. The efficacies in the presence of a bacterial food source and bovine serum albumin (BSA) were investigated., Methods: Four brands of multipurpose solutions and a hydrogen peroxide disinfecting system (Oxysept) for soft CLs, and four disinfecting solutions for Rigid Gas Permeable (RGP) lenses were tested against three species of Acanthamoeba. Page's amoebic saline was included as a negative control and standard solutions of disinfecting agents, 6% hydrogen peroxide and 0.5% chlorhexidine, as positive controls. The effects of the presence of Pseudomonas aeruginosa and BSA on effectiveness were assessed., Results: None of the CL solutions tested achieved a 1-log reduction in viability of all three Acanthamoeba species within the manufacturer's recommended disinfection times. The presence of P. aeruginosa did not significantly affect disinfecting capacity of multipurpose solution solutions but reduced activity of RGP solutions and the hydrogen peroxide system. BSA reduced trophozoicidal activity of all solutions. Bland and Altman analysis showed good agreement between Vi-cell and hemacytometer., Conclusions: The Vi-Cell analyzer offers a simple and effective method of determining amoebicidal activity. Our results show that the CL solutions tested could not satisfactorily kill Acanthamoeba.

Background: Environmental contamination with methicillin-resistant Staphylococcus aureus (MRSA) poses a significant risk in the epidemiology of infection. This study aimed to assess the effectiveness of disinfection in clinical areas by assessment of the wipe-rinse method to MRSA in the immediate patient environment, on both the bed rails and the cleaning wipes., Methods: The environmental disinfection procedures of 8 MRSA-positive hospitalized patients in 2 orthopedic wards were evaluated. A total of 56 pre- and postdisinfection samples from the bed rails as well as pre- and postuse wipes samples were collected., Results: The average MRSA loads on the bed rails before and after disinfections were 4.4 colony-forming units (cfu)/cm(2) and 0.4 cfu/cm(2), respectively, the process reducing MRSA survival from a mean of -0.70 log to -1.65 log. The mean difference of MRSA survival detected on the wipes after each wiping ranged from 0.13 to 0.42 log., Conclusion: The presence of MRSA in the proximity of the patient, ie, the bed rails as well as the cleaning tool (the wipe), was demonstrated in this study. If thorough rinsing was not conducted between wiping, bacteria accumulated on the wipes, which can result in cross transmission., (Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.)

We investigated changes in regulatory genes, vraS and graR, during development of vancomycin non-susceptibility in a patient with methicillin-resistant Staphylococcus aureus who failed therapy and following in-vitro vancomycin exposure and a subsequent drug-free growth period. Minimum Inhibitory Concentration (MICs) were determined and genes sequenced at each stage. After 30 days of vancomycin exposure, the strain attained maximum MIC (20 mg/L) and was resistant to all antibiotics. Reversion to vancomycin susceptibility occurred 21 days after removal. We observed mutations in vraS and graR during non-susceptibly development and novel stop codons in the reverted strain. Mutations in graR appear important for development of intermediate susceptibility to vancomycin. The results suggest that monitoring of vancomycin therapy could allow earlier change to appropriate agents., (© 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.)

Reduced biocide susceptibility in staphylococci is associated with quaternary ammonium compound (qac) gene-encoding efflux proteins. This study compared the prevalence of antiseptic-resistance genes (qacA/B, smr) in staphylococci colonising nurses and non-healthcare workers. Staphylococcus aureus and coagulase-negative staphylococci (CoNS) isolated from 249 nurses were compared for qacA/B and smr positivity with carriage isolates from non-healthcare workers. Associations between qac genes and antibiotic resistance were investigated and minimum inhibitory concentrations (MICs)/minimum bactericidal concentrations (MBCs) to benzalkonium chloride and chlorhexidine determined. Both genes had higher prevalence in CoNS from nurses (OR: 8.4; 95% CI: 5.4-13.2) and qacA/B was more common in nurses'S. aureus isolates than those of the general population (OR: 5.5; 95% CI: 2.7-11.2). Meticillin-resistant S. aureus (MRSA) carriage was low (3.2% nurses; 0.5% general population). The risk of harbouring qacA/B and smr was associated with presence of mecA (OR: 2.9; 95% CI: 1.8-4.8) and contact with MRSA-infected patients (OR: 2.0; 95% CI: 1.0-3.9) in S. aureus and CoNS. S. aureus with qac genes displayed significantly more antibiotic resistance and all gene-positive isolates had higher MICs and MBCs to antiseptics. Increased prevalence of antiseptic-resistance genes in staphylococci from nurses indicates that the hospital environment could exert selective pressure for carriage of these strains. The increased proportion of qac genes in meticillin-resistant strains suggests co-selection of these genes, as does the increased carriage of gene-positive strains by those in contact with MRSA-positive patients. Reduced antiseptic susceptibility may allow persistence of organisms in the presence of low level residues and contribute to survival of MRSA., (Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

Elevated rates of methicillin-resistant Staphylococcus aureus (MRSA) carriage have been reported in veterinary personnel, suggesting an occupational colonization risk. Hong Kong veterinary personnel (n = 150) were sampled for coagulase-positive staphylococci (CPS) nasal colonization. Risk factors for colonization were assessed by questionnaire. Isolates were identified and antibiotic susceptibility determined. All CPS isolates were investigated for mecA carriage, SCCmec type and PVL genes. Two subjects were colonized with methicillin-resistant CPS: one with MRSA (spa type t002 (CC5), SCCmec type II) and one with methicillin-resistant Staphylococcus pseudintermedius (MRSP) (MLST type ST71, SCCmec type II-III). MLST type ST71 S. pseudintermedius strain is the predominant MRSP clone circulating in dogs in Europe and in Hong Kong. The low MR-CPS colonization rate may be associated with low levels of large animal exposure or low rates of MRSA colonization of companion animals in Hong Kong. Colonization with non-aureus CPS, which may cause human infection, must also be considered in veterinary personnel., (© 2009 The Authors. © 2009 Blackwell Verlag GmbH.)

Objectives: Several methods have been introduced for detection of vancomycin-non-susceptible Staphylococcus aureus [heterogeneous vancomycin-intermediate S. aureus (hVISA) and vancomycin-intermediate S. aureus (VISA)]. However, the limitations of these methods can delay appropriate therapy for the patient. This study evaluated the spiral gradient endpoint (SGE) technique for detection of hVISA/VISA., Methods: The SGE method was evaluated for intra-batch, inter-batch and inter-observer reproducibility in comparison with MICs determined by agar dilution. Three media, Mueller-Hinton agar, brain heart infusion agar and brain heart infusion agar with 5% glucose, were evaluated. The SGE method was compared with agar dilution for correlation of MIC and susceptibility category using control strains, clinical isolates and induced vancomycin-non-susceptible strains., Results: The SGE method had good reproducibility and there was excellent correlation of MICs generated by SGE using brain heart infusion agar with those by agar dilution (r(2) =0.950), with no difference in resistance categories generated by the two methods. All VISA isolates were correctly identified and the method allowed easy identification of hVISA by means of the trailing endpoint., Conclusions: SGE offers a simple, rapid and cost-effective alternative method for the detection of hVISA/VISA for the routine laboratory. Early recognition of vancomycin-non-susceptible strains can allow the change to appropriate antibiotics, resulting in potentially better patient outcomes.

Objectives: Increasing antibiotic resistance and interest in matching antibiotic therapy with pharmacokinetic/pharmacodynamic characteristics of isolates has led to increasing demands for determination of MICs. This can lead to increased costs for the laboratory. The spiral gradient endpoint (SGE) technique, a low-cost method of MIC determination, was developed some years ago. Although the technique showed good correlation with reference methods, it was not widely employed, mainly due to the introduction of alternative methods. We have revisited this technique and evaluated it for the determination of MICs for fastidious organisms., Methods: The SGE method was first optimized for fastidious organisms using Haemophilus influenzae. Intra-batch and inter-batch reproducibility was determined for H. influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and Neisseria gonorrhoeae. The method was then evaluated by comparison of MICs for clinical isolates of these organisms determined by SGE with those determined with the reference method., Results: Optimization of the technique resulted in a method with excellent reproducibility for all organisms tested [SD 0.10-0.337; coefficient of variation (CV) 8.59%-18.66%]. These SDs/CVs were lower than those of the reference methods (0.27-2.34; 31.0%-63.8%). There was excellent correlation of the MICs with the reference methods (0.908-0.930) and insignificant differences in numbers of strains in each resistance category, with no tendency for SGE to produce higher or lower MICs than the reference method (P > 0.05)., Conclusions: SGE was shown to be reproducible and produced results that correlated well with standard techniques for fastidious organisms. The method offers a rapid, flexible, cost-effective alternative for smaller laboratories and for routine use in developing countries.

Purpose: To determine and compare the cytotoxic effects on porcine corneal epithelial cells of commercially available multipurpose solutions (MPS) using fluorescein staining and flow cytometry (FCM)., Methods: Effects of exposure time of 10 s to 10 min of MPS containing polyquaternium-1 (MPS-A), polyaminopropyl biguanide (MPS-B), and polyhexanide (MPS-C), on porcine corneal epithelial cells were determined. Cell viability and membrane integrity were assessed by Annexin V-FITC/7-AAD staining and FCM. In further trials, whole corneas were immersed in MPS and control (buffered saline), and corneal fluorescein staining assessed before FCM analysis., Results: Significantly higher percentages of 7-AAD-stained cells (early necrosis) were observed at all exposure times for MPS-A than for other solutions and control (p < 0.05). Exposure time in MPS-A and 7-AAD-stained cell proportions showed significant correlation (r = 0.9957; p < 0.0001). Significantly more cells dual-stained with Annexin V-FITC/7-AAD (late necrosis) after 5 min MPS-A exposure (11.8 +/- 1.1%), compared with 1.2 +/- 0.9% (MPS-B), 0.9 +/- 0.5% (MPS-C), and 1.8 +/- 0.2% (control). However, only 10 min exposure resulted in significant increases in fluorescein grades (p < 0.001), with median grade 0.75 for MPS-A, and 0.50 for the other MPS., Conclusions: MPS exposure, especially MPS-A, affected the viability and integrity of porcine corneal epithelial cells. Furthermore, our results confirmed that fluorescein staining correlates poorly with cytotoxicity. As fluorescein staining lacks sensitivity to determine cytotoxic effects of ophthalmic solutions, more objective and sensitive assessment methods such as differential staining and FCM should be developed.

Objectives: To determine the prevalence and risk factors for chlamydial infection in cross-border truck drivers., Methods: 225 Hong Kong-based cross-border truck drivers were screened for chlamydial infection. Associations between infection and potential risk factors were determined by questionnaire., Results: 8.5% of drivers were positive for chlamydial infection. Of 62% of drivers reporting recent sex with commercial sex workers (CSW), 39% had not used condoms. 75% of drivers with extramarital sex partners (ESP) also frequented CSW and 47% of this group had not used condoms with CSW. 43.3% PCR-positive cases reported symptoms. No risk factor was associated with chlamydial infection after adjustment, although "had sex with ESP" approached significance., Conclusions: The prevalence of chlamydial infection among cross-border truck drivers was not strikingly high, although drivers engaged in sex with both ESP and CSW, with many admitting unprotected intercourse. The findings highlight the importance of promoting safe sex to truck drivers.

Case reports have indicated transmission of Staphylococcus aureus between humans and pets. We investigated associations between level of contact between dog and owner, and S. aureus colonization. In a cross-sectional study, nasal carriage and antibiotic susceptibility of S. aureus was determined for 830 dogs and 736 owners. Relatedness of isolates was investigated using antibiograms and pulsed-field gel electrophoresis (PFGE). Associations between carriage and demographics or amount of contact between owners and dogs were documented. S. aureus was isolated in 24% of humans and 8.8% of dogs. Antibiotic resistance was significantly more common in canine isolates. Of 17 owner/dog colonized pairs, six were indistinguishable by PFGE. Colonization of dogs was not associated with close human contact, but was strongly associated with health-care occupations (OR 3.29, 95% CI 1.49-7.26, P=0.002). In outbreak situations health-care workers' pets should be considered as a source of S. aureus. High rates of resistance indicate increased monitoring of antibiotic use in veterinary practice is needed.

Ten methicillin-resistant Staphylococcus aureus (MRSA) isolates from healthy owners and their pets were characterised by susceptibility testing, staphylococcal chromosome cassette (SCC)mec and agr typing, and detection of the Panton-Valentine leukocidin (PVL) genes. Two human and three dog isolates harbouring SCCmec type III appeared to be of hospital origin. The five remaining isolates carried SCCmec type IV, with three being multidrug-resistant. One type IV isolate was PVL-positive and a prototypic agr type 3, typified by strain MW2. This is the first report of this type in association with nasal carriage. Drug resistance may be increasing among community isolates of MRSA.

Purpose: The aims were to determine the level of compliance of contact lens wearers, to identify which procedures have highest levels of non-compliance and to study the effectiveness of a compliance enhancement strategy on the level of compliance., Methods: The level of compliance for each subject was evaluated with a self-administered questionnaire together with microbiological examination of their contact lenses, lens cases and lens care solutions. The effect of an intervention to improve the level of compliance was determined by a controlled trial. A regular self-review exercise on proper lens handling was given to the test group once every three months for 12 months. The levels of compliance and contamination of contact lenses and lens care accessories between test and control groups were compared at the end of the 12-month period to evaluate the effect of the intervention., Results: Sixty-five subjects who were experienced contact lens wearers were recruited and 60 completed the study. All showed some degree of non-compliance in the care of their contact lenses and lens accessories. Most (about 60 per cent) were non-compliant with at least six of a total of 15 lens care procedures. The most common non-compliant behaviour among contact lens wearers was associated with the care of the lens case. By the end of the study period, our compliance enhancement strategy did not appear to have had a significant effect on the behaviour of our subjects, except for improvement in the care of lens cases. Compliance for other procedures improved in both test and control groups., Conclusion: All subjects showed some degree of non-compliance and the spectrum of non-compliance was wide. The poorest levels of compliance were associated with care of the lens case, which was also the most frequently contaminated item. Our compliance enhancement strategy showed a significant difference in improvement in compliance between the intervention and control groups only in the care of lens cases.

Purpose: The purpose of this study is to determine if there are changes in the ocular flora of overnight orthokeratology (ortho-k) patients, and the levels of contamination of their lenses and lens accessories, and to correlate compliance with levels of contamination., Method: Normal ocular flora of 41 subjects was determined twice before commencing ortho-k lens wear by culture of the lower conjunctiva. Further specimens were collected on six follow-up visits after beginning lens wear, as were samples from their lenses, cases, and suction holders. A questionnaire on lens care was administered after the fifth visit., Results: Three subjects provided conjunctival samples yielding Staphylococcus aureus on one occasion before lens wear, one being positive for this organism after beginning lens wear. Of 38 subjects yielding no growth or only normal eye flora before use, 28 remained free of ocular pathogens after beginning lens wear. Only four subjects had positive cultures on more than one occasion after lens wear. There was no significant difference in isolation levels of pathogens with lens wear (p = 0.423). Lens culture of 54% of subjects yielded no growth or normal flora only; lenses of 16 subjects yielded potential pathogens, including three subjects contaminated on more than one occasion. Lens isolates did not match the organisms transiently colonizing the eye. Lens case, the most frequently contaminated item, was associated with lens contamination (p < 0.001), the same organism being isolated from both items in 11 subjects. Lens suction holder was less frequently contaminated. Neither lens case nor suction holder contamination was associated with isolates from the eye. Reported good compliance correlated with lack of contamination in all but one subject. The most frequent breaches in the lens care protocol were failure to clean, disinfect, and replace the lens case., Conclusion: Ocular flora was not altered by ortho-k lens wear over an extended period, and patients remained free of infection. Contaminants identified were generally of a transient nature. Most patients had significant contamination of at least one item, most frequently the lens case. Lens case isolates were significantly associated with those from the lens. The majority of patients reporting good compliance had low or no contamination of their lenses and accessories.

Although reports of isolation of methicillin-resistant Staphylococcus aureus (MRSA) from patients admitted from the community have increased, few studies have investigated colonization of healthy subjects. This study aimed to determine community levels of MRSA in Hong Kong. Nasal swabs from a cross section of young adults and family units were cultured for MRSA. Antibiotic sensitivities and risk factors for carriage were determined and clonal relationships were investigated by pulsed-field gel electrophoresis (PFGE). Overall carriage was low (1.4%), and associated with health-care exposures (OR 13.56, 95% CI 1.11-165.21). Subjects working in health care yielded multi-resistant MRSA strains, but isolates from non-hospital-exposed subjects were methicillin-resistant only. Strains indistinguishable by PFGE were carried by subjects working together, and some spread to other contacts was observed. MRSA colonization in the community is rare in Hong Kong and is largely associated with working in health care. Community-acquired staphylococcal infections may be treated with agents effective against methicillin-sensitive strains.

Purpose: To determine the effect of storage time and temperature on the efficacy of four multipurpose solutions for soft contact lenses., Method: Aliquots of multipurpose solutions (OPTI-FREE Express, ReNu MultiPlus, COMPLETE and SOLO-care) stored at different temperatures over a 3-month period, were challenged with contact lens-related ocular pathogens, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans., Results: The results showed that OPTI-FREE Express had the best activity against Ps. aeruginosa at all temperatures; ReNu MultiPlus performed well at 25 degrees C; COMPLETE barely achieved activity requirements at all temperatures, and lost efficacy after 2 months. SOLO-care maintained its activity best against Ps. aeruginosa at 30 degrees C. Storage at fridge temperature reduced activity of all solutions. Regardless of storage temperature, activities of all solutions against S. aureus markedly decreased by 2 months. Only OPTI-FREE Express met FDA requirements against C. albicans., Conclusion: Performance of multipurpose solutions is affected by time and temperature of storage. Contact lens users should be aware that the efficacy of opened solutions may not be sustained for as long as 3 months. Manufacturers should reconsider their recommendations to further safeguard the ocular health of contact lens wearers.

Objective: To determine the prevalence of penicillin and vancomycin tolerance in clinical isolates of Streptococcus pneumoniae., Design: Laboratory testing of 50 consecutive clinical isolates., Setting: District hospital, Hong Kong., Patients: Fifty patients with pneumonia or meningitis who were admitted to a district hospital in Hong Kong between August and October 2002., Main Outcome Measures: Lysis, as assessed by loss of optical density at 4 hours at 540 nm, and reduction in viable count expressed as the log of the number killed ('log kill') after exposure of cultures to 10 times the minimum inhibitory concentration of penicillin and vancomycin., Results: Of the 50 isolates, five (10%) were tolerant to penicillin and one (2%) was tolerant to vancomycin., Conclusion: This is the first report of vancomycin tolerance in Streptococcus pneumoniae in Hong Kong. Because vancomycin tolerance is associated with clinical failure in the treatment of pneumococcal meningitis, increased monitoring for resistant strains of organisms is suggested.

A cross-sectional survey was conducted to determine prevalence and assess risk factors for carriage of antibiotic resistant strains of Streptococcus pneumoniae in healthy school children in Hong Kong. Throat swabs were collected from 1455 subjects and written questionnaires providing demographic data and medical history were completed by parents. The overall carriage rate of Streptococcus pneumoniae was 3.5%, of which 49% were penicillin resistant. High levels of resistance to tetracycline (73%), erythromycin (52%), trimethoprim (66%) and ciprofloxacin (57%) were observed. Carriage was associated with presence of a younger sibling (OR = 1.79) and use of antibiotics (OR = 2.31). High use of day care and small size of housing units did not result in a high rate of carriage. The low rate of carriage may be linked to high use of antibiotics, geographical factors or ethnicity. High rates of antibiotic resistance reflect heavy use of antibiotics by general practitioners.

Gene therapy is in clinical trials in a number of countries, raising the question of whether different ethical standards can be justified in different countries. One key issue is how divergent are the perceptions and bioethical reasoning of peoples around the world. An International Bioethics Survey with 150 questions, including 35 open ones, was developed to look at how people think about diseases, life, nature, and selected issues of science and technology, biotechnology, genetic engineering, genetic screening, and gene therapy. The mail response survey was conducted in 1993 among the public in Australia, India, Israel, Japan, New Zealand, Russia, and Thailand, and the same written survey was conducted among university students in Australia, Hong Kong, India, Japan, New Zealand, The Philippines, Russia, Singapore, and Thailand. Similar questions were included in an international high school education bioethics survey among high school teachers in Australia, Japan, and New Zealand. Further international comparisons to the United States and Europe are made. About three-quarters of all samples supported personal use of gene therapy, with higher support for children's use of gene therapy. The diversity of views was generally similar within each country. The major reasons given were to save life and increase the quality of life. About 5-7% rejected gene therapy, considering it to be playing God, or unnatural. There was very little concern about eugenics (0.5-2%), and more respondents gave supportive reasons like "improving genes," especially in Thailand and India. Support for specific applications was significantly less for "improving physical characters," "improving intelligence," or "making people more ethical" than for curing diseases like cancer or diabetes, but there was little difference between inheritable or noninheritable gene therapy.