Biomedical subjects
Publications and source records attributed to H D Isenberg.
Osteomyelitis caused solely by an anaerobic organism is uncommon. We report a case of recurrent Clostridium bifermentans bacteremia resulting in metastatic osteomyelitis involving the sacrum, spine, and ribs. The emergence of resistance of this organism to imipenem and metronidazole is noteworthy because of the usual susceptibility of clostridial species to these antibiotics.
Candida parapsilosis is an important nosocomial pathogen that can proliferate in high concentrations of glucose and form biofilms on prosthetic materials. We investigated the genotypic diversity and slime production among 31 isolates of C. parapsilosis from individual patients with bloodstream or catheter infections. DNA subtyping was performed by using electrophoretic karyotyping plus restriction endonuclease analysis with BssHII followed by pulsed-field gel electrophoresis. Slime production was evaluated by growing organisms in Sabouraud broth with 8% glucose and examining the walls of the tubes for the presence of an adherent slime layer. Overall there were 14 DNA subtypes among the 31 isolates. Eighty percent of the isolates produced slime; 67% of the isolates were moderately to strongly positive, 13% were weakly positive, and 20% were not slime producers. The ability of isolates of a given DNA type to produce slime under these conditions was variable. The results of these studies indicate moderate genotypic variation among clinical isolates of C. parapsilosis. The propensity of these isolates to form slime in glucose-containing solutions suggests that this phenotypic characteristic may contribute to the ability of C. parapsilosis to adhere to plastic catheters and cause infections.
PURPOSE: To identify the type, rate, burden, and pattern of contamination of boxed, clean but nonsterile gloves in our intensive care unit (ICU). MATERIALS AND METHODS: The fingertips of the first, middle, and last two pairs of gloves in 29 boxes in routine service in our ICU were cultured. The first of each of these three sets were removed aseptically, the second in a routine fashion. RESULTS: We found 16 of 29 (55%) first pairs removed aseptically to be contaminated with a mean bioburden of 1.8 colony-forming units (CFU). The percentage contamination and bioburden did not change significantly with position in the box. Use of routine compared with strict aseptic technique increased the rate of contamination by only 11% (95% confidence interval [CI] -0.05 to +0.27 percentage points) and bioburden by only a mean of 3.4 colonies per pair (CI -0.51 to +4.90 CFU). The length of the time the boxes were open and in use was unrelated to whether the final aseptically removed pair was sterile or contaminated. The predominant organisms were coagulase-negative staphylococci. CONCLUSIONS: One half the pairs of latex examination gloves in our ICU were sterile despite repeated barehanded access to the boxes. Those contaminated exhibited a small bioburden of low pathogenic potential. No pattern of contamination or unsafe duration of box use were observed. The use of boxed, clean, nonsterile gloves appears safe for routine use in an ICU.
The hypothesis that catheter-related sepsis (CRS) may be preceded by contamination of the catheter hub was tested in neonates with central venous catheters. Cultures of the catheter hub were obtained three times per week. One hundred thirteen catheters were placed in 88 patients. Of 35 episodes of sepsis, 28 were catheter-related, for a catheter sepsis rate of 1.03/100 catheter-days. CRS occurred in 26 (23%) of 113 catheters. In 10 of 28 episodes, the infecting microorganism was cultured from the hub before its culture from blood obtained at the time of clinical sepsis. In an additional 5 cases, a culture of the catheter hub at the time of clinical sepsis yielded the same isolate as the blood culture. Thus, 54% of episodes of CRS were preceded by or coincided with contamination of the hub. The catheter hub may be a major portal of entry for microorganisms causing sepsis in a neonatal intensive care unit.
The vascular catheter hub is a potential portal of entry for microorganisms that cause catheter-related sepsis. Thus, a reduction in catheter hub contamination might reduce the incidence of catheter-related sepsis. To develop a regimen suitable for reducing microbial contamination of the catheter hub, we experimentally contaminated catheter hubs and assessed the efficacies of disinfectant solutions. Catheter hubs were incubated overnight with suspensions of Staphylococcus epidermidis, Pseudomonas aeruginosa, or Candida parapsilosis. After removal of unattached microorganisms, the catheter hubs were swabbed by rotating cotton swabs dipped in 1% chlorhexidine, 1% chlorhexidine in 70% ethanol, 70% ethanol, 97% ethanol, or normal saline. Posttreatment swabs of the catheter hub were obtained and cultured quantitatively. The cleaning regimens containing ethanol were the most effective. Seventy percent ethanol was more effective than chlorhexidine and is likely to be the safest treatment. We conclude that cleaning of the catheter hub with disinfectant can dramatically reduce microbial contamination.
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This study reports the appropriate disinfection methods for flexible and rigid laryngoscopes when used in an outpatient setting. This investigation presents evidence that an appreciable number of laryngoscopes are contaminated during use. A brief tap water rinse serves to eliminate gross soil of host origin known to interfere with disinfectant efficacy. Disinfection with 3.2% glutaraldehyde (Cidexplus) for 10 minutes effectively eliminated microbial contaminants. Since potentially harmful microorganisms were included among the more than 100 isolates during our baseline experiments, the need to eliminate bacteria, viruses, fungi, and protozoa from laryngoscopes is obvious and can be attained readily.
OBJECTIVE: To assess whether daily ingestion of yogurt containing Lactobacillus acidophilus prevents vulvovaginal candidal infections. DESIGN: Crossover trial for at least 1 year during which patients were examined for candidal infections and colonizations while receiving either a yogurt-free or a yogurt-containing diet. Patients served as their own controls. SETTING: Ambulatory infectious disease center in a teaching hospital providing tertiary care. PATIENTS: Thirty-three women with recurrent candidal vaginitis were eligible after recruitment from community practices and clinics and through advertising. Twelve patients were eliminated for protocol violations. Of the remaining 21 patients, 8 who were assigned to the yogurt arm initially refused to enter the control phase 6 months later. Thus, 13 patients completed the protocol. INTERVENTIONS: Women ate yogurt for 6 months of the study period. MEASUREMENTS: Colonization of lactobacilli and candida in the vagina and rectum; candidal infections of the vagina. MAIN RESULTS: Thirty-three eligible patients were studied. A threefold decrease in infections was seen when patients consumed yogurt containing Lactobacillus acidophilus. The mean (+/- SD) number of infections per 6 months was 2.54 +/- 1.66 in the control arm and 0.38 +/- 0.51 per 6 months in the yogurt arm (P = 0.001). Candidal colonization decreased from a mean of 3.23 +/- 2.17 per 6 months in the control arm to 0.84 +/- 0.90 per 6 months in the yogurt arm (P = 0.001). CONCLUSION: Daily ingestion of 8 ounces of yogurt containing Lactobacillus acidophilus decreased both candidal colonization and infection.
OBJECTIVE: Determine the epidemiology and risk factors for colonization with vancomycin-resistant Enterococcus faecium. DESIGN: Survey; case-control study. SETTING: Children's hospital. PATIENTS: Pediatric oncology patients. INTERVENTION: Contact isolation, restriction of vancomycin prescribing. RESULTS: There was a high prevalence of colonization with vancomycin-resistant enterococci among pediatric oncology patients. The length of hospitalization and the administration of vancomycin and other intravenous antibiotics was associated with colonization. Prevention of colonization was associated with restriction of vancomycin use and contact isolation. CONCLUSIONS: Vancomycin use may predispose to colonization with vancomycin-resistant E faecium. Vancomycin-resistant E faecium may be nosocomially spread. Contact isolation and restriction of vancomycin use may prevent spread of vancomycin-resistant E faecium.
Twenty-seven episodes of bacteremia caused by Staphylococcus warneri were identified at Long Island Jewish Medical Center in New York between 1984 and 1989. Fourteen of these were thought to represent true bacteremias and 13 to represent contaminants. Of the 14 true bacteremias, 5 were in pediatric and 9 were in adult patients. Eight of 14 patients (57%) had catheter-related bacteremia and 5 of 14 had bacteremia of unknown source. There was one case of fulminant native valve S. warneri endocarditis. All cases of catheter-related bacteremia, except one, were nosocomially acquired, and 75% of these patients had an underlying immunosuppressive condition. Only 40% of patients with bacteremias of unknown source were immunocompromised, and S. warneri appeared to be noninvasive in this group. Interestingly, all five of the pediatric isolates were oxacillin susceptible, although four of five were resistant to penicillin, despite the fact these patients were hospitalized an average of 29 days. In contrast, seven of nine adult isolates were resistant to both oxacillin and penicillin. The only case of native valve S. warneri endocarditis occurred in a patient who had no known underlying valvular heart disease, but had an underlying immunosuppressive condition. Identification to species level of coagulase-negative staphylococci may lead to appreciation of the importance of bacteria such as S. warneri as human pathogens.
Legionella micdadei is the second most common species implicated in the occurrence of Legionella pneumonia (D. J. Bremer, Semin. Respir. Infect. 4:190-205, 1987). Although there has been a reported lung abscess caused by dual infection (L. micdadei and L. pneumophila), there are no known cases of L. micdadei as the only causative organism. We report a case of a patient with a lung abscess from which L. micdadei was the sole organism isolated.
The Septi-Chek AFB system for the recovery of mycobacteria from clinical specimens was compared with a conventional approach using Lowenstein-Jensen and Middlebrook 7H11 agars. A total of 1,532 clinical specimens were analyzed; 132 yielded mycobacteria. Mycobacterium tuberculosis and Mycobacterium avium complexes were the predominant isolates. With the conventional combination of Lowenstein-Jensen and 7H11 agars, 75.8% of the isolates were recovered; the Septi-Chek AFB allowed recovery of 100% of the isolates. Septi-Chek AFB required less time for the detection of mycobacteria than did the conventional media.
An apparent single-source outbreak of Candida tropicalis sternal wound infections in eight patients was investigated by utilizing DNA restriction fragment analysis (RFA) with HindIII and BstNI. All eight outbreak isolates appeared to be identical and were easily differentiated from control isolates by DNA RFA. Compared with an arbitrarily selected reference outbreak isolate, greater than or equal to 95% of the bands in the restriction digests identified by a computerized image analysis system from each of the outbreak isolates were identical versus 13 to 53% of the bands in any of the nine control isolates. Outbreak strains were significantly more likely to match the reference outbreak isolate than were controls (P less than 0.0001). The RFA was greatly facilitated by the use of computerized image analysis and confirmed the epidemiologic link between a scrub nurse and the infected patients.
A patient with a long history of scleroderma and gastrointestinal malabsorption requiring total parenteral nutrition was admitted with Candida zeylanoides fungemia. The yeast responded to therapy, but on two subsequent admissions for episodes of fever the blood cultures yielded the same yeast. The identity of the Candida species was established biochemically by both the API (Analytab) and Vitek system approaches. C. zeylanoides ATCC 20356 and ATCC 7351 served as controls for these analyses and for antifungal susceptibility studies and restriction endonuclease analyses of chromosomal DNA. These investigations indicated that representative isolates of the yeasts from the three episodes were identical and differed in several respects from the ATCC strains, which did not share many of the characteristics bands with the DNA restriction fragment analysis. C. zeylanoides variants capable of tolerating 35 degrees C can complicate the recovery of patients, especially individuals compromised by their underlying disease.
A study to delineate the feasibility of a biphasic-culture approach for detection and isolation of mycobacteria from clinical specimens except blood was conducted in four medical centers. The biphasic system (Septi-Chek AFB, Roche Diagnostic Systems, Nutley, N.J.) was compared with conventional mycobacterial isolation media and the BACTEC system. Septi-Chek AFB showed the highest degree of mycobacterial recovery. In addition, Septi-Chek AFB consistently shortened the time required for recovery of mycobacteria from clinical specimens and supported the growth of small inoculum numbers of stock cultures of 14 mycobacterial species. The study indicates the feasibility and potential advantages of the biphasic approach for detection and isolation of mycobacteria.
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Candida tropicalis was isolated from the sternal wounds of eight coronary bypass patients from 18 to 89 days postoperatively; infections were limited to soft tissue in five patients but involved the sternum in three patients. Analysis of surgery records implicated one individual as the potential source of the yeast; this was confirmed by microbiological studies of fingertips and nasopharynx cultures of all personnel in contact with these patients. Only the suspect nurse, then acting as a scrub nurse and not as a circulator, infected the eight patients. Her removal from the cardiac team terminated the cluster outbreak.
A case of broncholithiasis in which both Histoplasma and actinomycotic organisms were demonstrated is presented. The etiology of broncholithiasis is discussed, with particular emphasis on the relationship between the organisms identified.