Do 'chlorine covers' exert a sustained bactericidal effect on the bacterial hand flora?

Treatment of skin with chlorine generates 'chlorine covers' which, in a previous study, exerted significant sustained bactericidal effects against transient skin flora on the upper arm and forearm. In this investigation, this effect was studied on both the transient and resident flora of the hands using test models for the evaluation of hand disinfectants as agreed upon in Austria and Germany. Chlorine covers were generated by bathing hands in a solution of 2% sodium tosylchloramide for 1 min. Subsequently, this cover was destroyed on one, randomly selected, hand by bathing it in a solution of 0.5% sodium thiosulphate for 15 s. The amount of chlorine on the fingertips of chlorinated hands was 2.2 +/- 0.4 micrograms/cm2; that on subsequently dechlorinated hands was 0.2 +/- 0.1 microgram/cm2. In experiments with artificially contaminated hands (Escherichia coli), the kinetics of bacterial die-off were the same on both hands. Also, in experiments with resident flora, the kinetics of bacterial die-off did not suggest bacterial reductions that increase with the duration of contact with the chlorine cover. It was concluded that with the test models used, a significant sustained antimicrobial effect of the chlorine cover could not be demonstrated on hands.

Polymerase chain reaction for detection of Chlamydia pneumoniae in gargled-water specimens of children

The objective of the present study was to establish the occurrence of Chlamydia pneumoniae by direct detection in gargled-water specimens obtained from 193 children suffering from acute or chronic respiratory infections. Specimens were analyzed by an indirect immunofluorescence test (IIF), a genus-specific antigen enzyme immunosorbent assay (EIA) and the polymerase chain reaction (PCR). The pathogen was detected in three children by PCR only. As underlying disease, chronic obstructive bronchitis resistant to therapy was reported. In two of the children, the presence of pneumonia could be verified by X-ray. With a detection threshold of target DNA obtained from two inclusion forming units (IFU), the PCR proved clearly more sensitive than EIA becoming positive at levels of 100 IFU and above. No interpretable results could be obtained for the IIF.

Epidemiological analysis of Candida yeasts by pulsed-field gel electrophoresis

The purpose of this study was to determine whether yeast isolates from mothers and their new-borns are of the same genotype. In this investigation, 103 parturient mothers and their children were examined for colonization by yeasts by sampling the vaginal secretions at delivery and by taking swabs from the oral mucosa and the anus of the children on the third day after parturition. The samples were cultured on Sabouraud glucoseagar and incubated for 48 h at 37 degrees C. Differentiation of the isolates was achieved biochemically by means of the Vitek AMS system and morphologically on rice extract agar. Subsequently DNA fingerprinting analysis was carried out by means of pulsed-field gel electrophoresis (PFGE). In six cases we could prove the presence of Candida spp. in the mothers as well as in their children. In all cases the strains isolated from mother and child showed the same banding pattern. Likewise, the strains isolated from the vaginal secretion and the vaginal epithelium of individual women were identical. The differences observed between strains isolated from different women were small to middling. This shows PFGE to be an efficient procedure to demonstrate the relation between strains derived from mothers and their newborns.

Single and multiple strain colonization in patients with Helicobacter pylori-associated gastritis: detection by macrorestriction DNA analysis

Helicobacter pylori isolates from 18 patients were examined by macrorestriction DNA analysis to determine whether > or = 2 strains can coexist in the human stomach. Four biopsy samples from different sites in each patient's stomach were cultured, and 12-14 clones of H. pylori per patient were analyzed. DNA of 15 of the 18 isolates was digestible: 12 by NotI and 3 by NruI. Within 14 of these digestible isolates, the patterns of all clones were identical. The isolate of 1 patient showed two digestion patterns, a finding that was confirmed by arbitrary primer polymerase chain reaction. The typeable isolates of all patients, except 2 who underwent gastroscopy on the same day, differed markedly from each other. These results indicate a noticeable discrepancy between the pronounced interpatient heterogeneity and the rare intrapatient variation of H. pylori.

Kinetics of specific IgG antibodies for monitoring the effect of anti-Helicobacter pylori chemotherapy

A total of 104 patients with recurrent duodenal ulcer were treated with either ranitidine plus amoxicillin plus metronidazole or ranitidine plus placebo. To study the effect of the eradication of Helicobacter pylori on the systemic immune response in an IgG ELISA, sera were drawn from all patients before the onset of therapy and at 6, 16 +/- 2, 32 +/- 2, and 60 +/- 2 weeks after therapy. In patients with eradication of the organism, a significant (P < .001) reduction of the specific IgG titer occurred. This was not observed in patients without bacterial eradication. If a titer reduction of > 50% was taken as an indicator for eradication of H. pylori, the sensitivity of the serologic test was 97.6%-99.7%. Its specificity increased with the interval to the onset of chemotherapy from 56.3% to 97.6%. Serologic tests are simple to perform and cause very little discomfort to the patient.

Comparison of three methods for the determination of the sensitivity of Helicobacter pylori to metronidazole

A comparison of various methods for the determination of the sensitivity of Helicobacter pylori to metronidazole was undertaken. The validity of the agar dilution, the disc diffusion and the Epsilometer (E) test was studied using a total of 86 strains, 16 of which were known to be resistant to metronidazole. All tests were carried out on Mueller-Hinton agar with 5% sheep blood. The results of the disc diffusion and the E-test were highly significantly (P < 0.001) associated with those of the agar dilution test, which was taken as a standard (r = -0.96 and r = 0.96, respectively). Investigation of the accuracy of the repetitive (n = 10) testing ten sensitive and one resistant strains, showed that the disc diffusion test led to a systematic and significant (2p < 0.001) underestimation of the MIC values calculated from the inhibition zone diameters via linear regression. In contrast, the results of the E-test did not differ significantly from those of the agar dilution test. The precision of the agar dilution test was significantly worse (2p < 0.005) than the E-test and the disc diffusion test. Because of its accuracy and significantly better precision, the E-test is recommended as the best and simplest method for routine antibiotic sensitivity testing of H. pylori.

Test models for hygienic handrub and hygienic handwash: the effects of two different contamination and sampling techniques

Two methods for artificial contamination of hands and two sampling techniques to recover the test organisms were compared for their effects on the results of two post-contamination hand treatments: a handrub with two portions of 3 ml of 2-propanol 60% v/v for 1 min, and a handwash with liquid soap 20% w/v for 1 min followed by a 15 s rinse. The two contamination methods involved a short immersion of the hands (up to the middle of the mid-hand) in a suspension of the test organism followed by either air-drying (3 min) or drying by rubbing the hands' vigorously against each other (3 min) in a standardized way. The two sampling techniques consisted of rubbing the fingertips in either 10 ml trypticase soy broth (TSB) against the bottom of a Petri dish; or 100 ml TSB against glass beads contained in a bowl. Sixteen volunteers were randomly allotted to four blocks of four. They carried out the four possible combinations of two treatments and two contamination methods in a series of four tests arranged in a Latin-square design. In addition, the two sampling techniques were compared with each other concurrently by sampling of the right and left hand each with a different one of the two techniques. The alcoholic handrub reduced the release of test organisms significantly (2P less than 0.005) more effectively, by 1.1-1.3 x log10, than did the handwash with liquid soap, regardless of the contamination or sampling method. Whereas the two recovery techniques yielded virtually identical results in corresponding situations, the method of artificial contamination affected the mean reduction factors, strongly.(ABSTRACT TRUNCATED AT 250 WORDS)

A new plate medium for rapid presumptive identification and differentiation of Enterobacteriaceae

A new selective differential agar medium for rapid presumptive identification of Enterobacteriaceae from water and food samples is described (EMX ID agar). By a combination of fluorogenic and chromogenic substrates, the medium detects the presence of beta-D-glucuronidase, beta-D-galactosidase, beta-D-xylosidase, tryptophane deaminase and H2S; additionally, cytochrome-oxidase and indole production can be demonstrated. This medium provides an inexpensive means for simple and rapid presumptive identification of E. coli and coliforms and for the differentiation within the Klebsiella-Enterobacter and the Proteus-Providencia-Morganella group. Furthermore, it allows to distinguish between the H2S-positive Enterobacteriaceae Citrobacter freundii, Salmonella spp., S. arizonae, Edwardsiella, Proteus mirabilis, P. vulgaris and some oxidase-positive bacteria.

Evaluation of a commercial latex test for serological diagnosis of Helicobacter pylori infection in treated and untreated patients

The value of a commercially available latex test (Pyloriset) for the diagnosis of Helicobacter pylori infection by demonstration of specific antibodies was compared with that of direct diagnostic methods such as culture, biopsy-urease test and microscopy of fuchsin-stained smears. The sera were from 136 patients who prior to this study either had or had not been treated for Helicobacter pylori-infection simultaneously with amoxicillin (3 x 750 mg/day) and metronidazole (3 x 500 mg/day) for 12 days. On average, the sensitivity of the test was 90%. The specificity with sera from untreated patients was 75.9%; with sera from treated patients specificity was 22.2%, 28% and 20% 1, 3 and 6 months respectively after start of treatment. Only as late as one year after the onset of chemotherapy did the specificity return to 67%. Because of its low specificity this test does not offer any advantage over other tests in the detection of Helicobacter pylori-infection or in monitoring the chemotherapeutic success.

The influence of cosmetic additives on the acceptability of alcohol-based hand disinfectants

A prospective, randomized double-blind study with intra-individual comparison of the results was undertaken with 20 volunteers to assess the influence of cosmetic additives on the acceptability of a mixture of n-propanol (50% v/v) and isopropanol (30% v/v) for hand disinfection. Three to 5 ml of antiseptic was rubbed into the hands until dry 15 times a day, 5 days a week and for 2 weeks per preparation. For self-assessment the parameters 'appearance', 'intactness', 'turgor' and 'sensation' were evaluated weekly by visual analogue; for assessment by a dermatologist the same parameters except 'sensation' were used. Each score was compared before and after treatment. The antimicrobial efficacy of the alcoholic mixture was equivalent to or better than the standard (isopropanol 60% v/v, 1 min). The frequent application of these antiseptic preparations caused a slight but significant deterioration of the skin condition as judged by both self-assessment and dermatologist; however, this was significantly less when the antiseptic contained cosmetic additives. It is concluded that the addition of suitable emollients can significantly increase the acceptability of alcoholic disinfectants.

Comparison of ELISA antigen preparations alone or in combination for serodiagnosing Helicobacter pylori infections

The immunoglobulin G antibody response to Helicobacter pylori was assessed in 78 patients with non-ulcer dyspepsia using five different antigen preparations. All patients were endoscoped and biopsied. The H pylori state was determined histologically on at least two endoscopic biopsy specimens using a modified Giemsa stain. The ultracentrifuged cell sonicate, acid glycine extract, and 120 kilodalton protein antigens were specific in diagnosing infection (95-98%), but had only moderate sensitivity (70-84%). By mixing either of the two complex antigens with the 120 kilodalton protein, the sensitivity of the test was increased to 97% without affecting the high specificity. The combination of ultracentrifuged sonicate or acid glycine extract with the 120 kilodalton protein therefore seems to be superior to the individual antigen preparations and is particularly suitable for the serodiagnosis of H pylori infection.

Frequency of occurrence and characterization of catalase negative Campylobacter isolated from human feces in Vienna

Of a total of 124 Campylobacter (C.) strains isolated 1988 from fecal specimens, 4 (3.2%) were catalase-negative. Two strains were catalase-negative variants of C. jejuni. The other two were identified as C. upsaliensis on the basis of their biochemical properties and of the results of DNA-DNA hybridization with biotinylated probes from C. upsaliensis and C. jejuni. Both had been isolated from patients after their return from Asia (India and Thailand, respectively). In one case, a significant decrease of the antibody titre was observed within 12 months when the patient strain was used as an antigen. Since this patient had been suffering from diarrhoea during her stay and since with the exception of amoebic cysts, no other intestinal pathogen was isolated, C. upsaliensis is thought to have been the reason for the diarrhoeal episode.

In vitro susceptibility of Campylobacter jejuni and Campylobacter coli isolated in Austria to erythromycin and ciprofloxacin

More than 200 strains of Campylobacter (C.) jejuni/coli isolated in 1985 and 1987/88 from human fecal specimens were tested for their susceptibility to erythromycin and ciprofloxacin. Their MIC90 as assessed by agar dilution tests was 2.0 and 0.5 mg/l, respectively. Thus, all strains were regarded as susceptible to ciprofloxacin. With 2 out of 55 strains of C. coli the MIC of erythromycin was 8.0 mg/l. Therefore, only 3.6% of the C. coli strains were resistant to erythromycin. All 209 strains of C. jejuni proved to be susceptible to erythromycin.

Comparison of different antigen preparations in an evaluation of the immune response to Campylobacter pylori

This study presents a novel approach to the analysis of protein antigens of Campylobacter pylori for use in serology. Protein fractions of this bacterium were resolved in polyacrylamide gel electrophoresis, eluted from gel strips in an electric field and used for coating of microtiter plates in an ELISA-type assay run with a small set of sera from both infected and non-infected patients. Reactivity and discriminative power of the different fractionated antigens (1-9) and crude antigen preparations (A-C) were compared. Better discrimination was achieved between positive and negative sera with high molecular weight fractionated preparations (antigens 8 and 9) than with low molecular weight fractions. Among the crude antigen preparations, antigens A (sonicated whole cells) and C (ultracentrifugated sonicate) seem to have a better discriminative power than antigen B (acid glycin extract).

A comparison of the effects of preoperative whole-body bathing with detergent alone and with detergent containing chlorhexidine gluconate on the frequency of wound infections after clean surgery. The European Working Party on Control of Hospital Infections

In a prospective, randomized, double-blind, placebo-controlled study involving 27 surgical units in six European countries, the effect of preoperative whole-body bathing on two occasions with a detergent containing chlorhexidine (CHX+) on the incidence of wound infection in elective, clean surgery was compared with two bathings with a detergent without chlorhexidine (CHX-). In the CHX+ group 2.62% of 1413 patients and in the CHX- group 2.36% of 1400 patients subsequently became infected. The infection rate in the CHX+ group was 1.11 times that in the CHX- group with 95% confidence limits ranging between 0.69 and 1.82. Consequently, bathing patients twice preoperatively with chlorhexidine-detergent did not reduce the incidence of infection of clean wounds.

Effect of chlorhexidine-containing detergent, non-medicated soap or isopropanol and the influence of neutralizer on bacterial pathogenicity

In handwashing experiments with Salmonella typhimurium the effect of chlorhexidine (CHX) on the pathogenicity of surviving bacteria was assessed with and without a neutralizer in a mouse model of infection. Without neutralizer the LD50 of CHX handwash fluids was raised. Neutralizer in suspensions of untreated bacteria caused a reduction of LD50 up to 1.2 logs. Thus, in contrast to soap or alcohol, CHX without neutralizer exerted a slight 'depathogenizing' action and neutralizer a slight 'pathogenizing' effect in the experimental model used. However, in comparison to the efficiency of handwashing procedures which reduce the number of bacteria available for transfer by at least 3.0 to 4.2 logs, the size of these effects seems to be negligibly small and unpredictable. Therefore, the single most important parameter in assessing the potency of disinfectants remains the reduction of viable counts with time.

Efficacy of coumermycin, ofloxacin and vancomycin against methicillin-resistant Staphylococcus aureus in vitro and in experimental infections of mice

In vitro, coumermycin (a bis-hydroxicoumarin gyrase inhibitor) proved significantly more active than ofloxacin and vancomycin against 100 strains of methicillin-resistant Staphylococcus aureus (MRSA). The MIC90 was 0.5 microgram/ml, whereas the corresponding figures for the other antimicrobials were 2.0 and 4.0 micrograms/ml. In vivo, an otherwise lethal septicemia, induced by intraperitoneal administration of a MRSA in mice, was "successfully treated" in 50% of the animals (ED50) with the following dosages (microgram/g b. wt.): coumermycin 0.9, ofloxacin 10.8, vancomycin 22.4. The ED50 of coumermycin was significantly (2 p less than 0.01) different from those of the other drugs. Renal infection as produced in mice by transcutaneous inoculation of the same MRSA was treated with either of the antimicrobials at different dosages (single doses of 0.0 or 1.6 or 6.3 or 25.0 micrograms/g b. wt., twice daily) during 6 days. The largest reductions of viable counts in the kidneys at each dosage as compared to the bacterial counts of untreated animals were achieved with coumermycin (3.4 or 5.5 or 7.7 log10). These reductions are significantly (2 p less than 0.01) different from those achieved with the comparable dosages of ofloxacin and vancomycin which were 0.1 or 1.8 or 2.8 and 0.4 or 1.4 or 3.0 log10 respectively. After a single subcutaneous injection of 250 micrograms mean concentrations in serum of mice for coumermycin were 6.2-5.0 micrograms/ml for 8 h, for ofloxacin 2.0-0.5 micrograms/ml for 2 h, and for vancomycin 14.7-2.5 micrograms/ml for 2 h. Coumermycin and ofloxacin could be alternatives to vancomycin in the therapy of human infections due to MRSA.

The efficacy of antimicrobial treatment in Campylobacter pylori-associated gastritis and duodenal ulcer

The efficacy of various antimicrobial and anti-ulcer agents on the elimination of Campylobacter pylori in duodenal ulcer patients was investigated. Ranitidine, cimetidine, pirenzepine, aluminium phosphate gel as well as combinations of H2-receptor antagonists or pirenzepine + penicillin V, ciprofloxacin, ofloxacin, phenyl-mercuryborate or rifampicin had no influence on C. pylori in vivo. Short term elimination of C. pylori was achieved in 3/15 patients treated with ranitidine + bacampicillin and in 1/5 treated with cimetidine + metronidazole. This elimination was accompanied by a significant reduction of polymorphonuclear infiltration of the antral mucosa. Development of bacterial resistance was observed in patients with additional quinolones, metronidazole and rifampicin but not in patients treated with betalactam antibiotics.

Occurrence, serotypes and biotypes of thermophilic Campylobacters isolated in Vienna

During the 1982-1986 period of all bacterial pathogens found to have caused diarrhoea, 35% belonged to the genus Campylobacter (C). Approximately 70% of the strains were isolated from persons under the age of 30 years, with a distinct peak of occurrence in the autumn. Biotyping and serotyping according to Lior yielded the following results: C. jejuni biotype I: 32.9%, C. jejuni biotype II: 48.6%, C. coli biotype I: 10.3%, C. coli biotype II: 8.2%. From the 121 strains serotyped, 118 (97.5%) were typable. The serotypes most frequently encountered were type 1 (15.7%), 4 (9.9%), 2 and 11 (7.4% each). There were 2 familial outbreaks of Campylobacter enteritis which could be completely elucidated by biotyping and serotyping. One outbreak was caused by C. jejuni biotype I serotype 11, the other by C. jejuni biotype II serotype 6. Considering the frequent occurrence of Campylobacter infections, isolates should be routinely typed. The existing typing methods and schemes are highly developed.

Evaluation of procedures for hygienic hand-disinfection: controlled parallel experiments on the Vienna test model

Controlled parallel experiments were performed on the Vienna test model for the evaluation of procedures for hygienic hand-disinfection in three laboratories (Vienna, Mainz, Birmingham). The degerming activity of four procedures, each taking 1 min, was assessed repeatedly and compared with that of a standard disinfection procedure (ST) using isopropanol 60% (v/v). The mean log reductions (mean log RF) for each procedure were as follows: n-propanol 50% (v/v) 4.85 and 5.14 in Vienna (V) and Mainz (M) respectively, ethanol 70% (v/v) + chlorhexidine-gluconate 0.5% (w/v), 4.01 (V), 3.76 (M) and 4.00 in Birmingham (B). Washing procedures were less effective, mean log RF's of 3.19 (V), 3.49 (M) and 3.04 (B) were obtained with povidone-iodine soap, and 2.91 (V), 3.37 (M) and 3.27 (B) with a liquid phenolic soap. Analysis of variance on the data from Vienna and Mainz revealed significant differences of means not only between procedures ('preparations') but also on repeat testing. To compensate for the influence of variables such as test subjects, laboratory and day, the Vienna test model provides a method of standardization by testing a ST in parallel with the test procedure (P). Standardization of the results was obtained by pair-wise substraction, log RFPi-log RFSTi. Analysis of variance on the resulting values demonstrated that comparability of the results between laboratories and on repeat testing was achieved. The relative variation of the measurements within the laboratories ranged from 0.9 to 4.2%. As assessed by power-analysis, a disinfection procedure will be detected as significantly (P = 0.1) inferior to the standard processes in 95 of 100 experiments if it produces a mean log RF that is at least 0.55-0.65 log units smaller than that of the standard.