Comparative evaluation of the hygienic efficacy of an ultra-rapid hand dryer vs conventional warm air hand dryers.

AIMS: To compare an ultra-rapid hand dryer against warm air dryers, with regard to: (A) bacterial transfer after drying and (B) the impact on bacterial numbers of rubbing hands during dryer use. METHODS AND RESULTS: The Airblade™ dryer (Dyson Ltd) uses two air 'knives' to strip water from still hands, whereas conventional dryers use warm air to evaporate moisture whilst hands are rubbed together. These approaches were compared using 14 volunteers; the Airblade™ and two types of warm air dryer. In study (A), hands were contaminated by handling meat and then washed in a standardized manner. After dryer use, fingers were pressed onto foil and transfer of residual bacteria enumerated. Transfers of 0-10(7) CFU per five fingers were observed. For a drying time of 10 s, the Airblade™ led to significantly less bacterial transfer than the other dryers (P < 0·05; range 0·0003-0·0015). When the latter were used for 30-35 s, the trend was for the Airblade to still perform better, but differences were not significant (P > 0·05, range 0·1317-0·4099). In study (B), drying was performed ± hand rubbing. Contact plates enumerated bacteria transferred from palms, fingers and fingertips before and after drying. When keeping hands still, there was no statistical difference between dryers, and reduction in the numbers released was almost as high as with paper towels. Rubbing when using the warm air dryers inhibited an overall reduction in bacterial numbers on the skin (P < 0·05). CONCLUSIONS: Effective hand drying is important for reducing transfer of commensals or remaining contaminants to surfaces. Rubbing hands during warm air drying can counteract the reduction in bacterial numbers accrued during handwashing. SIGNIFICANCE AND IMPACT OF THE STUDY: The Airblade™ was superior to the warm air dryers for reducing bacterial transfer. Its short, 10 s drying time should encourage greater compliance with hand drying and thus help reduce the spread of infectious agents via hands.

Detection of a new erm(X)-mediated antibiotic resistance in Egyptian cutaneous propionibacteria.

A total of 107 antibiotic-resistant propionibacteria were isolated from the face of 102 Egyptian acne patients, dermatology staff and controls. Erythromycin-clindamycin-resistant propionibacteria were chosen to detect erm(X) gene and it was detected in 29 of 107 (27%) strains. However, just 7 strains had IS1249I, 3 of them had also Tn5432. The erm(X) gene which is not carried on Tn5432 confers inducible resistance to telithromycin by erythromycin or clindamycin. The DNA sequences of the PCR amplification products of this new erm(X)-mediated antibiotic resistance showed >99% identity to the erm(X) gene isolated from a Corynebacterium jeikeium. Southern blotting analysis of the erm(X)-specific probe shows that there were two copies of this resistance gene integrated within the chromosomal DNA. This is the first report of erm(X) being carried by Propionibacterium acnes outside Europe. Whilst the gene is associated with Tn5432 in some strains, the data suggests other genetic element carrying erm(X). The high carriage of erm(X) may affect the efficacy of clindamycin and macrolides for acne treatment in Egypt.

Pseudomonas aeruginosa: a formidable and ever-present adversary.

Pseudomonas aeruginosa is a versatile pathogen associated with a broad spectrum of infections in humans. In healthcare settings the bacterium is an important cause of infection in vulnerable individuals including those with burns or neutropenia or receiving intensive care. In these groups morbidity and mortality attributable to P. aeruginosa infection can be high. Management of infections is difficult as P. aeruginosa is inherently resistant to many antimicrobials. Furthermore, treatment is being rendered increasingly problematic due to the emergence and spread of resistance to the few agents that remain as therapeutic options. A notable recent development is the acquisition of carbapenemases by some strains of P. aeruginosa. Given these challenges, it would seem reasonable to identify strategies that would prevent acquisition of the bacterium by hospitalised patients. Environmental reservoirs of P. aeruginosa are readily identifiable, and there are numerous reports of outbreaks that have been attributed to an environmental source; however, the role of such sources in sporadic pseudomonal infection is less well understood. Nevertheless there is emerging evidence from prospective studies to suggest that environmental sources, especially water, may have significance in the epidemiology of sporadic P. aeruginosa infections in hospital settings, including intensive care units. A better understanding of the role of environmental reservoirs in pseudomonal infection will permit the development of new strategies and refinement of existing approaches to interrupt transmission from these sources to patients.

Antibiotic-resistant acne: lessons from Europe.

BACKGROUND: Propionibacterium acnes and P. granulosum are widely regarded as the aetiological agents of inflammatory acne. Their proliferation and metabolism are controlled using lengthy courses of oral and/or topical antibiotics. Despite numerous reports of skin colonization by antibiotic-resistant propionibacteria among acne patients, accurate prevalence data are available only for the U.K. OBJECTIVES: To determine the prevalence of skin colonization by antibiotic-resistant propionibacteria among acne patients and their contacts from six European centres. METHODS: Skin swabs were collected from 664 acne patients attending centres in the U.K., Spain, Italy, Greece, Sweden and Hungary. Phenotypes of antibiotic-resistant propionibacteria were determined by measuring the minimum inhibitory concentrations (MIC) of a panel of tetracycline and macrolide, lincosamide and streptogramin B (MLS) antibiotics. Resistance determinants were characterized by polymerase chain reaction (PCR) using primers specific for rRNA genes and erm(X), followed by nucleotide sequencing of the amplified DNA. RESULTS: Viable propionibacteria were recovered from 622 patients. A total of 515 representative antibiotic-resistant isolates and 71 susceptible isolates to act as control strains were characterized phenotypically. The prevalence of carriage of isolates resistant to at least one antibiotic was lowest in Hungary (51%) and highest in Spain (94%). Combined resistance to clindamycin and erythromycin was much more common (highest prevalence 91% in Spain) than resistance to the tetracyclines (highest prevalence 26.4% in the U.K.). No isolates resistant to tetracycline were detected in Italy, or in Hungary. Overall, there were strong correlations with prescribing patterns. Prevalence of resistant propionibacteria on the skin of untreated contacts of the patients varied from 41% in Hungary to 86% in Spain. Of the dermatologists, 25 of 39 were colonized with resistant propionibacteria, including all those who specialized in treating acne. None of 27 physicians working in other outpatient departments harboured resistant propionibacteria. CONCLUSIONS: The widespread use of topical formulations of erythromycin and clindamycin to treat acne has resulted in significant dissemination of cross-resistant strains of propionibacteria. Resistance rates to the orally administered tetracycline group of antibiotics were low, except in Sweden and the U.K. Resistant genotypes originally identified in the U.K. are distributed widely throughout Europe. Antibiotic-resistant propionibacteria should be considered transmissible between acne-prone individuals, and dermatologists should use stricter cross-infection control measures when assessing acne in the clinic.

Phenotypic and genotypic characterization of antibiotic-resistant Propionibacterium acnes isolated from acne patients attending dermatology clinics in Europe, the U.S.A., Japan and Australia.

BACKGROUND: Propionibacterium acnes is the target of antimicrobial treatments for acne vulgaris. Acquired resistance to erythromycin, clindamycin and tetracyclines has been reported in strains from diverse geographical loci, but the molecular basis of resistance, via mutations in genes encoding 23S and 16S rRNA, respectively, has so far only been elucidated for isolates from the U.K. OBJECTIVES: To determine whether similar or different resistance mechanisms occur in resistant P. acnes isolates from outside the U.K. METHODS: The phenotypes and genotypes of 73 antibiotic-resistant strains of P. acnes obtained from the skin of acne patients in the U.K., U.S.A., France, Germany, Australia and Japan were compared. Antibiotic susceptibilities were determined by minimum inhibitory concentration (MIC) measurements, and polymerase chain reaction and DNA sequencing were used to identify mutations in genes encoding rRNA. RESULTS: Most erythromycin-resistant isolates (MIC(90) > or = 512 microg mL(-1)) were cross-resistant to clindamycin but at a much lower level (MIC(90) > or = 64 microg mL(-1)). As in the U.K., resistance to erythromycin was associated with point mutations in 23S rRNA in 49 of 58 strains. An A-->G transition at Escherichia coli equivalent base 2058 was present in 24 strains. This gave a unique cross-resistance phenotype against a panel of macrolide, lincosamide and type B streptogramin antibiotics. Two further point mutations (at E. coli equivalent bases 2057 and 2059) were identified (in three and 22 isolates, respectively) and these were also associated with specific cross-resistance patterns originally identified in isolates from the U.K. However, nine of 10 erythromycin resistant-strains from Germany did not exhibit any of the three base mutations identified and, in six cases, cross-resistance patterns were atypical. Consistent with previous U.K. data, 34 of 38 tetracycline-resistant strains carried a base mutation at E. coli 16S rRNA equivalent base 1058. Tetracycline-resistant isolates displayed varying degrees of cross-resistance to doxycycline and minocycline, but isolates from the U.S.A. had higher MICs for minocycline (4--16 microg mL(-1)) than isolates from other countries and, in particular, Australia. All the P. acnes isolates resistant to one or more of the commonly used antiacne antibiotics were sensitive to penicillin, fusidic acid, chloramphenicol and the fluoroquinolone, nadifloxacin. All but one isolate (from the U.K.) were sensitive to trimethoprim. CONCLUSIONS: This study shows that 23S and 16S mutations identified in the U.K. conferring antibiotic resistance in P. acnes are distributed widely. However, resistant strains were isolated in which mutations could not be identified, suggesting that as yet uncharacterized resistance mechanisms have evolved. This is the first report of high-level resistance to minocycline and is of concern as these strains are predicted to be clinically resistant and are unlikely to remain confined to the U.S.A. Epidemiological studies are urgently required to monitor how resistant strains are selected, how they spread and to ascertain whether the prevalence of resistance correlates with antibiotic usage patterns in the different countries.

Modifiable and nonmodifiable factors associated with osteoporosis in postmenopausal women: results from the Third National Health and Nutrition Examination Survey, 1988-1994.

We wished to study the relationship between modifiable and nonmodifiable factors that were correlated with osteoporosis using a national sample of women aged 50 years and older who have never been on hormone replacement therapy (HRT). We used a cross-sectional study design with a nationally representative sample with a detailed clinical examination and a home interview. Between 1988 and 1994, 1953 postmenopausal women who had never been on HRT, aged 50 years and older, were examined as part of the Third National Health and Nutrition Examination Survey (NHANES III). Mexican Americans and non-Hispanic blacks were oversampled to produce reliable estimates for these groups. Bone density measurements of four proximal femur sites were assessed by using x-ray absorptiometry (DEXA). A DEXA measurement at any single femur site indicated osteoporosis if it was >2.5 standard deviations (SD) below the reference mean of 20--29-year-old women. The study demonstrated that numerous factors, both modifiable and nonmodifiable, were significantly related to the prevalence of osteoporosis. The modifiable factors identified were participation in physical activity (three to five times per week) and body mass index (BMI). Nonmodifiable factors included age, race, and mother's history. With the aging population, osteoporosis is a growing concern for the medical community. It is suggested that educational strategies are needed to increase awareness of factors that contribute to maintaining bone health among postmenopausal women. Emphasis may be placed on maintaining regular physical activity.

Non-pathogenic Escherichia coli versus mesalazine for the treatment of ulcerative colitis: a randomised trial.

BACKGROUND: Ulcerative colitis has been suggested to be caused by infection and there is circumstantial evidence linking Escherichia coli with the condition. Our aim was to find out whether the administration of a non-pathogenic strain of E. coli (Nissle 1917) was as effective as mesalazine in preventing relapse of ulcerative colitis. We also examined whether the addition of E. coli to standard medical therapy increased the chance of remission of active ulcerative colitis. METHODS: This was a single-centre, randomised, double-dummy study in which 120 patients with active ulcerative colitis were invited to take part. 116 patients accepted; 59 were randomised to mesalazine and 57 to E. coli. All patients also received standard medical therapy together with a 1-week course of oral gentamicin. After remission, patients were maintained on either mesalazine or E. coli and followed up for a maximum of 12 months. A two-stage, conditional, intention-to-treat analysis was done. FINDINGS: 44 (75%) patients in the mesalazine group attained remission compared with 39 (68%) in the E. coli group. Mean time to remission was 44 days (median 42) in the mesalazine group and 42 days (median 37) for those treated with E. coli. In the mesalazine group, 32 (73%) patients relapsed compared with 26 (67%) in the E. coli group. Mean duration of remission was 206 days in the mesalazine group (median 175) and 221 days (median 185) in the E. coli group. INTERPRETATION: Our results suggest that treatment with a non-pathogenic E. coli has an equivalent effect to mesalazine in maintaining remission of ulcerative colitis. The beneficial effect of live E. coli may provide clues to the cause of ulcerative colitis.

Comparison of ARDRA and recA-RFLP analysis for genomic species identification of Acinetobacter spp.

The genus Acinetobacter is subdivided into genospecies on the basis of DNA relatedness of strains. Phenotypic tests are insufficient to identify the genospecies to which an isolate belongs. The effectiveness of two previously described PCR-based methods for genospeciating Acinetobacter spp. was compared using a group of 32 well-characterised strains representing six genospecies. Amplified ribosomal DNA restriction analysis (ARDRA) correctly identified all 32 strains. Using restriction fragment length polymorphism (RFLP) of recA PCR amplimers, only six of the 32 strains were correctly identified. Heterogeneity in the recA gene sequence was demonstrated within five of the genospecies. ARDRA proved to be a reliable method whereas analysis of recA RFLP profiles did not enable the genospecies of most of the isolates of Acinetobacter spp. to be determined.

Exceptional desiccation tolerance of Acinetobacter radioresistens.

The taxonomy of the genus Acinetobacter, which includes several important nosocomial pathogens, has been confused due to a lack of discriminatory phenotypic characteristics for identification. Molecular methods such as amplified ribosomal DNA restriction analysis (ARDRA) now enable the accurate identification of species. Ten clinical isolates of Acinetobacter radioresistens had genospecies confirmed by ARDRA but the APJ 20NE system, commonly used in clinical microbiology laboratories, mis-identified them as Acinetobacter lwoffii. Desiccation resistance of Acinetobacter spp. is an important attribute for their survival in the clinical environment. We investigated the ability of A. radioresistens to survive desiccation using an established glass surface model and compared the results to A. lwoffii and Acinetobacter baumannii. The 10 strains of A. radioresistens were extremely resistant to desiccation and survived for an average of 157 days at 31% relative humidity (RH). In contrast, two strains of A. lwoffii and three strains of A. baumannii survived for an average of three and 20 days respectively, at 31% RH, which was used as an approximation to climatic conditions in UK hospitals. A. radioresistens is thus well adapted for survival in the hospital environment and carriage on human skin and yet it is reported less frequently than A. lwoffii amongst clinical isolates. Cases of A. radioresistens infection may be under-reported due to mis-identification as A. lwoffii and further studies that use molecular identification methods are required to elucidate the role of A. radioresistens in human disease.

Survival of Acinetobacter baumannii on dry surfaces: comparison of outbreak and sporadic isolates.

Acinetobacter spp. are important nosocomial pathogens reported with increasing frequency in outbreaks of cross-infection during the past 2 decades. The majority of such outbreaks are caused by Acinetobacter baumannii. To investigate whether desiccation tolerance may be involved in the ability of certain strains of A. baumannii to cause hospital outbreaks, a blind study was carried out with 39 epidemiologically well-characterized clinical isolates of A. baumannii for which survival times were determined under simulated hospital conditions. The survival times on glass coverslips of 22 strains isolated from eight well-defined hospital outbreaks in a German metropolitan area were compared with the survival times of 17 sporadic strains not involved in outbreaks but rather isolated from inpatients in the same geographic area. All sporadic isolates have been shown by pulsed-field gel electrophoresis to represent different strain types. There was no statistically significant difference between the survival times of sporadic strains of A. baumannii and outbreak strains (27.2 versus 26.5 days, respectively; P < or = 0.44) by the Wilcoxon-Mann-Whitney test. All investigated A. baumannii strains, irrespective of their areas of endemicity or epidemic occurrence, have the ability to survive for a long time on dry surfaces. Antimicrobial susceptibility testing showed that A. baumannii outbreak strains were significantly more resistant to various broad-spectrum antimicrobial agents than sporadic strains. Both desiccation tolerance and multidrug resistance may contribute to their maintenance in the hospital setting and may explain in part their propensity to cause prolonged outbreaks of nosocomial infection.

PCR single strand conformational polymorphism can be used to detect the gene encoding SHV-7 extended-spectrum beta-lactamase and to identify different SHV genes within the same strain.

The PCR single strand conformational polymorphism (PCR-SSCP) technique described to identify mutants of the SHV beta-lactamases was extended to identify an SHV-7 type beta-lactamase. This was found in a strain of Klebsiella pneumoniae, the first recorded isolate in the UK to produce this type of enzyme. We also demonstrate that PCR-SSCP can be used to identify more than one SHV beta-lactamase gene in a single strain.

Influence of relative humidity and suspending menstrua on survival of Acinetobacter spp. on dry surfaces.

Acinetobacter spp. are being reported with increasing frequency as a cause of nosocomial infection and have been isolated from the skin of healthy individuals, patients, hospital staff, dry nonbiotic objects, and different pieces of medical equipment. Factors affecting the survival of Acinetobacter spp. under conditions closely similar to those found in the hospital environment were investigated in the present study to help us understand the epidemiology of nosocomial Acinetobacter infection. Bacterial cells were suspended in distilled water or bovine serum albumin and were dried onto glass coverslips and kept at different relative humidities. Cells washed from coverslips were used to determined viable counts. Freshly isolated strains of Acinetobacter spp. belonging to the clinically important Acinetobacter calcoaceticus-Acinetobacter baumannii complex were found to be more resistant to drying conditions (e.g., 30 days for A. baumannii 16/49) than American Type Culture Collection strains (e.g., 2 days for A. baumannii ATCC 9955). The majority of strains belonging to the Acb complex had survival times similar to those observed for the gram-positive organism Staphylococcus aureus tested in the experiment. Survival times were prolonged for almost all the strains tested when they were suspended in bovine serum albumin (e.g., 60 days for A. baumannii R 447) compared with those for strains suspended in distilled water (11 days for R 447). The survival times for strains at higher relative humidity (31 or 93%) were longer than those for strains of Acinetobacter kept at a relative humidity of 10% (11 days at 31% relative humidity and 4 days at 10% relative humidity for R447). These findings are consistent with the observed tendency of Acinetobacter spp. to survive on dry surfaces, and they can be transferred not only by moist vectors but also under dry conditions in a hospital environment during nosocomial infection outbreaks. The results obtained in the experiment support the previously suggested airborne spread of Acinetobacter spp. in hospital wards and repeated outbreaks after incomplete disinfection of contaminated dry surfaces.

Validation of use of whole-cell repetitive extragenic palindromic sequence-based PCR (REP-PCR) for typing strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and application of the method to the investigation of a hospital outbreak.

Acinetobacter spp. are being reported with increasing frequency as causes of nosocomial infection. In order to identify reservoirs of infection as quickly as possible, a rapid typing method that can differentiate epidemic strains from environmental and nonepidemic strains is needed. In 1993, a cluster of Acinetobacter baumannii isolates from five patients in the adult intensive therapy unit of our tertiary-care teaching hospital led us to develop and optimize a rapid repetitive extragenic palindromic sequence-based PCR (REP-PCR) typing protocol for members of the Acinetobacter calcoaceticus-A. baumannii complex that uses boiled colonies and consensus primers aimed at repetitive extragenic palindromic sequences. Four of the five patient isolates gave the same REP-PCR typing pattern as isolates of A. baumannii obtained from the temperature probe of a Bennett humidifier; the fifth isolate had a unique profile. Disinfection of the probe with 70% ethanol, as recommended by the manufacturer, proved ineffective, as A. baumannii with the same REP-PCR pattern was isolated from it 10 days after cleaning, necessitating a change in our decontamination procedure. Results obtained with REP-PCR were subsequently confirmed by ribotyping. To evaluate the discriminatory power (D) of REP-PCR for typing members of the A. calcoaceticus-A. baumannii complex, compared with that of ribotyping, we have applied both methods to a collection of 85 strains that included representatives of six DNA groups within the complex. Ribotyping using EcoRI digests yielded 53 patterns (D = 0.98), whereas 68 different REP-PCR patterns were observed (D = 0.99). By computer-assisted analysis of gel images, 74 patterns were observed with REP-PCR (D = 1.0). Overall, REP-PCR typing proved to be slightly more discriminatory than ribotyping. Our results indicate that REP-PCR typing used boiled colonies is a simple, rapid, and effective means of typing members of the A. calcoaceticus-A. baumannii complex.

Description of Leeds Acinetobacter Medium, a new selective and differential medium for isolation of clinically important Acinetobacter spp., and comparison with Herellea agar and Holton's agar.

Acinetobacter spp. are responsible for an increasing number of opportunistic, nosocomial infections. They have been isolated from diverse inanimate objects in the hospital environment and are resistant to most of the commonly used antibiotics. Existing media for the isolation of Acinetobacter spp. are either nonselective, allowing the growth of unwanted bacteria, or too inhibitory, inhibiting the growth of many Acinetobacter strains. For the rapid isolation and effective control of Acinetobacter infection, a new selective and differential medium, Leeds Acinetobacter Medium (LAM), has been developed to isolate Acinetobacter spp. from clinical and environmental sources. The concentration of antibiotics and other ingredients in this medium have been determined according to the results of MIC and viable counts performed for these ingredients. LAM was compared with other selective and differential media for the isolation of Acinetobacter spp. from a local hospital environment and proved to be better in terms of recovery and selectivity.