An in-use evaluation of an alcohol-based pre-surgical hand disinfectant.

OBJECTIVE: To determine whether alcohol hand disinfection is an effective alternative to traditional agents for the pre-surgical scrub. DESIGN: A prospective clinical trial of a 70% isopropanol pre-surgical hand disinfectant. SETTING: The operating room suites at two hospital sites in British Columbia. METHODS: Cases were selected to evaluate both short and longer procedures. The hand disinfectant was compared to agents in current use as surgical scrubs (4% chlorhexidine and 7.5% povidone-iodine). Surgical technique and glove use were not modified. Pre- and postoperative fingertip impression and "glove-juice" cultures were used to determine microbial burden, and hands were evaluated for skin integrity. RESULTS: There was no statistical difference between the microbial hand counts following use of the alcohol-based product or the current agents, for cases less than 2 hours' duration. Comparison of longer surgical cases revealed significantly better pre- and postoperative culture results with the alcohol hand rinse, but analysis of matched pairs showed no significant difference in microbial counts. The alcohol hand rinse was equivalent to the operative scrub in terms of skin integrity and user acceptability. CONCLUSION: An alcohol hand rinse was equivalently effective in reducing microbial hand counts as the traditional pre-surgical scrub, both immediately after hand disinfection and at the end of the surgical procedure.

A preliminary clinical investigation into the potential of blood lead levels to measure bone resorption in patients with skeletal metastases, using ICP-MS.

A simple, accurate and precise method to measure lead levels in whole blood by inductively coupled plasma-mass spectrometry (ICP-MS) has been developed. Blood samples were diluted (1 + 9) with 0.1% v/v Triton X-100 and 0.1% v/v nitric acid, and gave a limit of detection of 0.06 microgram/l (3sn). Spiking experiments demonstrated recoveries of 100 +/- 10% and verification against Seronorm reference and BCR certified reference materials gave experimental values in close agreement to the reference values. The methodology was used to conduct a feasibility study, involving a preliminary clinical investigation to assess the potential of whole blood lead levels as biochemical markers to measure bone resorption in patients with skeletal metastases and receiving treatment. The results from this feasibility study showed that the method remained under analytical control, giving inter and intra assay coefficients of variation of < 5%. This feasibility study also showed that the changes in the blood lead levels within individual patients were measurable and in many cases the patient's observed clinical performance demonstrated similar trends to the blood lead levels measured over time. Overall the results were encouraging and showed promise. Further and more detailed investigations into the use of lead and other trace metals as biomarkers of bone resorption is warranted.

The toilet as a transmission vector of vancomycin-resistant enterococci.

An elderly woman, admitted to the intensive care unit of a large university teaching hospital, was found to be colonized with vancomycin-resistant enterococci leading to the temporary closure of the unit. She had acquired the organism nosocomially, most likely from an environmental source, which had been contaminated when the toilet of a former patient, also colonized with vancomycin-resistant enterococci, had become blocked and overflowed throughout his and the adjoining room. This is the first report of a hospital toilet as the transmission vector for vancomycin-resistant enterococci.

Epidemic keratoconjunctivitis outbreak at a tertiary referral eye care clinic.

An outbreak of epidemic keratoconjunctivitis (EKC) occurred at a tertiary referral eye care clinic between late September and mid-November 1995. Before the outbreak, instruments were cleaned with 70% isopropyl alcohol and handwashing between patients was not routine. Infection control measures were implemented when the outbreak was recognized in mid-October. Control measures included triaging suspected cases to a separate waiting area, cohorting cases to a specific examining room, endorsing the use of gloves and handwashing during examinations of patients, and cleaning instruments with a buffered bleach solution. Thirty-six cases were diagnosed before the infection control measures were taken, and 3 cases were seen after the control measures were taken. Also, numerous secondary cases occurred in the community. No additional cases were diagnosed from DEcember to February 25, 1996. Acquisition of the infection was linked to visits to 4 of 20 physicians in the eye clinic with 61% of cases associated with visits to 1 of those 4 physicians. The use of diagnostic lenses applied directly to the eye was associated with infection (odds ratio = 2.83, 95% confidence interval = 0.79 to 10.4), although this did not reach statistical significance. The use of tonometers, ophthalmic solutions, or laser therapy was not associated with infection, and all environmental cultures were negative. This outbreak emphasizes the need for implementation of routine infection control guidelines to prevent nosocomial transmission of epidemic keratoconjunctivitis and stresses the need for appropriate disinfection of instruments.

The influence of surveillance methods on surgical wound infection rates in a tertiary care spinal surgery service.

STUDY DESIGN: A 1-year prospective study of the influence of surveillance methods on the surgical wound infection rates in a tertiary care spinal surgery unit. OBJECTIVES: To assess the effect of postdischarge surveillance, the diagnostic indications for surgery, and the type of procedure on the surgical wound infection rates. SUMMARY OF BACKGROUND DATA: Use of the National Nosocomial Infection Surveillance system for surgical wound infection resulted in infection rates above the published values for procedures performed by the Spinal Surgical Service. A preliminary review failed to find causes for these higher rates, and a study was undertaken to assess the influence of the surveillance methods used. METHODS: Patient information collected by the Spinal Surgical Service and surveillance data obtained by infection control were combined in a relational database. Surveillance after discharge was performed by regularly sending questionnaires to surgeons' offices. The diagnostic indications were assessed by dividing all patients into three groups: Class D (disc disease or spinal stenosis). Class T (spinal trauma within 60 days), and Class M (mostly complex spinal procedures for deformity and instability). Infection rates for the three diagnostic indication classes and for procedures with and without instrumentation were calculated. RESULTS: Postdischarge surveillance significantly increased the infection rates, mostly by detecting superficial infections that did not require readmission. Significant differences were noted between Class T and Class M patients undergoing lumbar posterior segmental instrumentation, despite the fact that they had a similar incidence of risk factors according to the National Nosocomial Infection Surveillance system. The surgical wound infection rates of the National Nosocomial Infection Surveillance system may not be appropriate standards for specialized units with a high incidence of complex clinical problems and complicated surgical procedures. CONCLUSIONS: Postdischarge surveillance, surgical procedure classification methods, and the indications for surgery (e.g., trauma, congenital deformity) influence the surgical wound infection rate. Current adjustments for some of these factors in the National Nosocomial Infection Surveillance system appear to be inadequate when used in a tertiary care facility.

Procurement, interpretation, and value of postmortem cultures.

The procurement, interpretation, and value of postmortem cultures is reviewed from the microbiologist's perspective. A brief description of the various procurement techniques is included and the factors involved in the contamination of specimens discussed. The interpretation of culture results is discussed by comparing postmortem specimens to routine laboratory samples such as blood cultures and sputum. The value of performing these cultures is discussed relevant to the individual postmortem examination and the research capabilities of the facility.

When the biological indicator is positive: investigating autoclave failures.

A series of positive biological indicators in steam autoclaves from different hospital departments within the same building were traced to blocked steam traps on building condensate lines. The steps taken during the investigation and a protocol for management of positive biological indicators are described.

Fulminating bacteremia and pneumonia due to Bacillus cereus.

We present two cases of rapidly progressing, fatal pneumonia caused by Bacillus cereus. These cases are interesting in that B. cereus, even from blood or sputum specimens, may often be considered a contaminant and receive inadequate attention. Also of interest was the fact that the two patients resided in the same area of the state, were welders by trade, and became ill within a few days of each other, yet there was no epidemiologic link between them.

Comparison of BACTEC 9240 and BacT/Alert blood culture systems in an adult hospital.

In a study comparing the BACTEC 9240 (Becton Dickinson, Canada Inc., Mississauga, Ontario, Canada) and the BacT/Alert (Organon Teknika, Scarborough, Ontario, Canada) blood culture systems, 6,437 sets of four bottles of 10,412 cultures submitted were deemed acceptable for evaluation. There were 586 clinically significant isolates from 544 positive blood cultures. Of the 544 positive blood cultures, 329 were positive in both systems, 157 were positive in the BACTEC 9240 system alone, and 58 were positive in the BacT/Alert system alone (P < 0.001). These cultures represented 421 bacteremic episodes, of which 290 were detected by both systems, 84 were detected by the BACTEC 9240 system alone, and 47 were detected by the BacT/Alert system alone (P < 0.001). The difference between the two systems in terms of microbial recovery was attributable largely to differences in the ability to grow staphylococci. Of 82 monomicrobial isolates of Staphylococcus aureus, 46 were isolated by both systems, 30 were isolated by the BACTEC 9240 system alone, and 6 were isolated by the BacT/Alert system alone (P < 0.0001). A similar pattern was noted in the case of coagulase-negative staphylococci, of which 48 were isolated in both systems, 46 were isolated in the BACTEC 9240 system alone, and 5 were isolated in the BacT/Alert system alone (P < 0.0001). The false-positive rate in the BACTEC 9240 system was 0.5%, and that in the BacT/Alert system was 1.2%. Both systems provided satisfactory service mechanically, and in terms of computer software and costs, both systems were similar. The differences in the recovery of organisms, notably staphylococci, may be due in part to the fact that in the present study the BacT/Alert medium did not contain antimicrobial agent-removing devices, whereas the BACTEC 9240 medium did. Until this difference is resolved, we consider the BACTEC 9240 system to more adequately meet our hospital's requirements.

Bacteremia with Acinetobacter species: risk factors and prognosis in different clinical settings.

Acinetobacter species are widespread environmental gram-negative coccobacilli that are associated with nosocomial infections; these bacteria are considered to be of relatively low virulence and rarely cause invasive disease. Fifty-two cases of bacteremic episodes due to Acinetobacter species were reviewed, and risk factors and outcomes of these cases were examined. It was noted that these cases belonged to a few clinical groups with markedly different outcomes. Eighteen patients had malignancies (predominantly hematologic), and bacteremia often developed after respiratory infection. Nine patients suffered traumatic injuries and developed bacteremia with Acinetobacter species after endotracheal intubation in the intensive care unit and respiratory colonization. Four burn patients, three of whom had burns covering > or = 50% of their body surface areas, had burn infections prior to bacteremia. While many patients had central venous catheters, in only four cases were the catheters clearly infected prior to the positive blood culture. Prior use of antibiotics was widespread in all groups of patients, and isolates showed high levels of antimicrobial resistance, particularly to beta-lactam agents. The outcome of infection correlated more closely with the type of underlying illness than with other factors such as biovar, polymicrobial bacteremia, or appropriate therapy. Patients with malignancies and burn patients fared poorly (10 of 18 and 2 of 4 patients, respectively, died), while trauma patients and patients with other illnesses did well.

Nontyphoidal, nonparatyphoidal salmonella septicemia in adults.

A 12-year review identified 21 patients with nontyphoidal, nonparatyphoidal salmonella septicemia. Eight of the patients had no predisposing factors. Factors identified included malignancy in five, recent surgery in four, alcoholism with aspiration pneumonia in two, chronic lung disease in two, diabetes in two, systemic lupus erythematosus in one and burns in one. Ten patients presented with gastroenteritis, two with localized abscesses, two with aspiration pneumonia and the remainder with nonspecific septicemia. Three patients died of underlying diseases and three died shortly after the septicemia of related causes. Six cases were nosocomial infection and were not related to hospital outbreaks. Salmonella septicemia with these serotypes is uncommon (1 per 14,000 admissions, 1 per 4000 blood cultures) and can occur in patients without diminished host resistance.

Yeast in blood cultures. Evaluation of factors influencing outcome.

Sixty episodes of candidemia occurring between January 1987 and September 1989 were retrospectively reviewed and the outcome was compared for three patient categories: neutropenic, postsurgical, and nonneutropenic nonsurgical. Because of increasing reports of resistant yeasts, minimal inhibitory concentrations (MICs) to amphotericin B (amB) were determined to examine its relationship to patient outcome. No significant differences between patient categories were found for selected risk factors, mortality, or species isolated, although there was a tendency for Candida tropicalis to occur in neutropenic patients. Statistical analysis using logistic regression showed that both an amB dose greater than 500 mg and a yeast MIC greater than 0.78 micrograms/ml were independent prognosticators of patient outcome.

Fatal trichosporonosis is not related to tolerance to amphotericin B.

A case of disseminated trichosporonosis in a 45-year-old female suffering from acute lymphocytic leukaemia is reported. The patient died of that mycosis despite of therapy with amphotericin B for which the pathogen had been proven susceptible in vitro.

Comparison of silver sulphadiazine 1 per cent, silver sulphadiazine 1 per cent plus chlorhexidine digluconate 0.2 per cent and mafenide acetate 8.5 per cent for topical antibacterial effect in infected full skin thickness rat burn wounds.

Silver sulphadiazine 1 per cent (SS), silver sulphadiazine 1 per cent plus chlorhexidine digluconate 0.2 per cent (SS + CD 0.2 per cent) and mafenide acetate 8.5 per cent (MA) were compared to assess the antibacterial effect of once daily application on experimental rat 20 per cent full skin thickness burn wounds seeded 24 h earlier with 10(8) microorganisms originally isolated from infected wounds of burned patients. Separate series evaluated Staph. aureus, Enterococcus faecalis, Enterobacter cloacae and Ps. aeruginosa. The mean concentration of all four organisms recovered after 1 week from full thickness biopsies of eschar and from separate biopsies of subjacent muscle was less in MA and SS + CD 0.2 per cent treated animals compared with those treated with SS alone. The mean concentration in muscle and eschar following treatment with MA was less for wounds seeded with Staph. aureus and Ps. aeruginosa than with SS + CD 0.2 per cent treatment, while the mean concentration in eschar application of SS + CD 0.2 per cent was less than with MA for E. faecalis seeded wounds.

A three-year study of positive blood cultures, with emphasis on prognosis.

A study of 37,156 blood cultures over a 3-year period yielded 1,972 positive blood culture episodes, of which 63% were of clinical significance, 26% represented contamination, 7% represented transient bacteremia, and 3% were of indeterminate significance. Mortality curves were calculated for clinically significant bacteremia according to etiologic organism and source. Several curves with different shapes were demonstrated. Quantitative differences were noted between cases of bacteremia arising from different sources and caused by different organisms. No mortality was associated with bacteremia of bone and joint origin. Mortality from bacteremic pneumococcal pneumonia, bacteremia with Escherichia coli of urinary tract origin, endocarditis, and beta-hemolytic streptococcal bacteremia showed an early plateau effect, with a drop before day 20. Cases of bacteremia from intravascular sources other than endocarditis were associated with no initial mortality, but mortality rose progressively after day 5. Bacteremia related to most organisms and sources was associated with mortality that continued until at least day 20.

Clinical comparison of isolator and BACTEC 660 resin media for blood culture.

The 10-ml Isolator system (E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.) was compared with the BACTEC 16A-17A nonradiometric resin system (Johnston Laboratories, Inc., Towson, Md.) for isolation of organisms from 6,839 paired blood cultures. Equal volumes of blood (6 to 10 ml for each Isolator and 3 to 5 ml for each BACTEC bottle) were cultured in parallel in the two systems, and 600 isolates that were judged to be clinically significant by chart review were recovered during the study. The BACTEC resin system detected 510 (85%) and the Isolator system detected 435 (72%) of the clinically significant isolates (P less than 0.001). Of 45 polymicrobial blood cultures, the BACTEC system detected 32 (71%) and the Isolator system detected 21 (47%) (P less than 0.05). Of 253 gram-negative bacilli isolated during the study, 30% were detected only in the BACTEC system and 16% were detected only in the Isolator system (P less than 0.001), and of 56 nonfermentative or fastidious gram-negative bacilli detected, 46% were recovered only in the BACTEC system, while 14% were detected only in the Isolator system (P less than 0.001). Of 86 streptococci isolated during the study, 30% were detected only in the BACTEC system, and 4% were detected only in the Isolator system (P less than 0.001). Recoveries of anaerobic bacteria, staphylococci, and yeasts were equivalent in the two systems. Organisms judged to be contaminants were detected in approximately 1% of the cultures in each system. The results suggest that use of resin media renders the BACTEC nonradiometric system equivalent or superior to the Isolator system for detection of clinically significant organisms in blood cultures.