Medium for susceptibility testing and yeast phase conversion of Blastomyces dermatitidis.

Cottonseed protein agar and a modified Tween-albumin casein hydrolysate (TAC) medium were compared for the yeast phase conversion of Blastomyces dermatitidis strains including fresh isolates as well as strains maintained in long-term storage. It was found that both media converted all the B. dermatitidis (mycelial phase) strains studied to yeast phase in three days. The TAC medium has the added advantage that it is clear and the growth can be recognized earlier than in the opaque cottonseed agar medium. The conversion in most cases was more than 95% and the morphology of the yeast cells was uniformly typical with broad base budding. There was a striking difference between the sensitivity of the yeast and mycelial phases of B. dermatitidis strains. The yeast phase was usually more sensitive to Amphotericin B than the mycelial phase of B. dermatitidis. Similarly, the yeast phases of four out of six strains were more sensitive to ketoconazole than their respective mycelial phases, while two strains showed identical sensitivity in cottonseed agar. The yeast phase organism was more susceptible to Amphotericin B when cottonseed medium was used whereas the yeast phase showed more susceptibility to ketoconazole in TAC medium. Since the sensitivity among the various strains differed, it is necessary to determine the antifungal susceptibility of the pathogenic phase of the organism for initiating proper therapy and monitoring effectiveness.

Scanning electron microscopy of bacteria adherent to intravascular catheters.

Scanning electron microscopy was used to assess the morphological features of coagulase-negative staphylococci adherent to polyvinylchloride intravascular catheter specimens. Clinical specimens were obtained by using patient catheters from which coagulase-negative staphylococci (greater than or equal to 15 colonies per catheter) grew on semiquantitative blood agar roll cultures. In vitro specimens were prepared by a previously published technique in which sterile polyvinylchloride catheters were immersed in 10(6) CFU of coagulase-negative staphylococci per ml suspended in phosphate-buffered saline. Unused sterile polyvinylchloride catheters were also examined. Scanning electron microscopy of unused sterile polyvinylchloride catheters demonstrated multiple linear surface irregularities. Scanning electron microscopy of infected patient catheters showed a diffuse amorphous material covering the entire surface and the presence of bacteria which appeared anchored to that surface by several different means. These included a slime layer, "foot" processes, and lodgement in surface irregularities. Scanning electron microscopy of in vitro specimens demonstrated no background surface coating, but it did show attachment of cocci to the surface by the same mechanisms as described for clinical specimens. These observations of similar means of attachment in clinical and in vitro specimens suggest that intrinsic catheter surface properties, bacterial surface features, and perhaps coating with host substances may all play a role in bacterial attachment to intravascular catheters. More sophisticated analysis of these interactions may clarify mechanisms of pathogenesis.

Late-onset, warfarin-caused necrosis occurring in a patient with infectious mononucleosis.

A 25-year-old man with Klinefelter's syndrome and recurrent thromboplebitis , for which he had been receiving long-term warfarin sodium therapy, had bilateral ecchymoses on the hips coincident with serologically confirmed Epstein-Barr virus-caused mononucleosis. Biopsy specimens taken from the hip lesions showed microscopic findings consistent with a diagnosis of warfarin necrosis. Direct immunofluorescence microscopy disclosed vessel-wall deposition of IgM and heavy upper-dermal deposition of IgG. Electron microscopy disclosed nonspecific endothelial cell blebs that projected into the vessel lumen. The temporal association of mononucleosis with the onset of warfarin necrosis suggests that the viral illness may have precipitated an immunologic endothelial surface reaction, leading to thrombosis and secondary hemorrhage with infarction. To our knowledge, the appearance of warfarin necrosis in a patient receiving long-term, stable anticoagulation therapy has not been previously reported.

Colonization of bacteria on polyvinyl chloride and Teflon intravascular catheters in hospitalized patients.

During an 8-month period all intravascular catheters were removed by sterile technique upon completion of use and submitted to the hospital microbiology laboratory. All catheters were routinely cultured by the semiquantitative culture technique, with greater than or equal to 15 colonies being defined as a positive result. Of the 687 Teflon catheters cultured, 6.9% were positive by culture, compared with 24.6% of 77 polyvinyl chloride catheters (P less than 0.001). Also, colonization of coagulase-negative staphylococci on polyvinyl chloride was more than on Teflon. These data suggest that polyvinyl chloride catheters are colonized more frequently with organisms than are Teflon catheters; additionally, there is an increased affinity of coagulase-negative staphylococci for polyvinyl chloride as compared with Teflon, substantiating our previous observations with an in vitro system. We conclude that the type of catheter material may be important in determining the incidence of catheter-related infections and in selective colonization by coagulase-negative staphylococci.

In vitro quantitative adherence of bacteria to intravascular catheters.

Adapting standard techniques, a simple in vitro system was devised to compare quantitative bacterial adherence to iv catheters of different compositions. Upon brief immersion of catheters in suspensions of Staphylococcus aureus, coagulase-negative staphylococci, and Escherichia coli, organisms adhered to catheter surfaces. After overnight growth in broth, organisms remained adherent and formed colonies, as shown by light and scanning electron microscopy. In addition, quantitative adherence using a blood agar roll technique, expressed as bacteria per square centimeter of catheter surface area per 10(6) colonies per milliliter inoculum, was calculated. Adherence was greater on polyvinylchloride (PVC) catheters (geometric mean 342) than on Teflon catheters (geometric mean 49.6) for coagulase-negative staphylococci (P less than 0.005). Also, the number of coagulase-negative staphylococci adherent to PVC catheters was significantly greater than for E. coli (geometric mean 70.6) at analogous inocula (P less than 0.02). Differences in bacterial adherence to the surface of iv devices may be important in the pathogenesis of catheter-associated infections. This in vitro method could prove useful in testing bacterial adherence properties of newly developed catheter materials, and allow development of catheters less prone to be associated with bacterial adherence and catheter-related infections.

Pulmonary and disseminated Mycobacterium simiae infection in humans.

Three patients with Mycobacterium simiae infection were seen during a 5-yr period. One patient with chronic infiltrative pulmonary disease had the diagnosis established by open lung biopsy. Two patients with normal chest roentgenograms had disseminated infection, one having had elective surgery for a nonfunctioning kidney. Caseating granulomata were discovered in kidney tissue sections. Both M. kansasii and M. simiae were subsequently recovered from bone marrow and urine cultures. The other patient had vertebral osteomyelitis, and M. simiae was isolated from tissue obtained by needle biopsy. To our knowledge, disseminated M. simiae infection has not been previously described.

Jaundice associated with nonhepatic Staphylococcus aureus infection. Does teichoic acid have a role in pathogenesis?

A previously healthy young man developed jaundice early in the course of a febrile illness caused by an unrecognized deep-seated Staphylococcus aureus abscess. The serum bilirubin level peaked 11 days before the abscess was discovered and drained. During this time the bilirubin level returned to normal, circulating immune complexes were detected, and the serum free teichoic acid antibody titer was elevated. Indirect immunofluorescent staining of liver tissue for teichoic acid revealed 2+ nuclear fluorescence of the hepatocytes. These findings suggested that circulating free teichoic acid was deposited in the liver and may have had an endotoxin-like effect in the hepatocytes. With the appearance of specific antibody in the serum, circulating teichoic acid was neutralized and further hepatic injury ceased.

Bacteremia due to Cedecea neteri sp. nov.

Three of four blood cultures from a patient with possible endocarditis were positive for a new species of Enterobacteriaceae which is named Cedecea neteri. This is the first reported case of bacteremia caused by a strain of Cedecea.

Nosocomial aspergillosis: a retrospective review of airborne disease secondary to road construction and contaminated air conditioners.

A retrospective review of autopsy records was performed to evaluate a clustering of patients shown to have invasive pulmonary aspergillosis during the period July 1, 1978 through October 31, 1980 at Milwaukee County Medical Center, Milwaukee, Wisconsin. During this period, ten patients, all of whom were immunosuppressed by either hematologic malignancy (two), advanced age (one), or iatrogenically to prevent rejection of renal allografts (seven) were found to have invasive pulmonary aspergillosis. Prospective and retrospective evaluations of the hospital environment correlated the clustering of cases to recent road construction, and recovery of Aspergillus fumigatus and A. flavus from window air conditioners used in the renal transplantation ward suggested that some of the patients had acquired the infection nosocomially. A review of autopsy records during a seven-year period following the initiation of the renal transplant program but antedating road construction of any major consequence revealed no invasive aspergillosis among any patient autopsied.

Localized oral blastomycosis mimicking actinomycosis.

A case of blastomycosis limited to the oral cavity is presented. The disease apparently originated in the mandible and eroded into the oral cavity. Secondary bacterial infection of the sinus tracts resulted in a clinical picture that mimicked cervicofacial actinomycosis. Appropriate microbiologic studies, including culture confirmation of the causative organism, were necessary to establish a definitive diagnosis.

Thoracic actinomycosis caused by actinomyces meyeri.

Two patients with chest infections caused by Actinomyces meyeri were seen during a 5-yr period. One patient was ill for 2 yr and had chronic infection manifested by bilateral cavitary and fibrotic changes on chest roentgenogram. A. meyeri was isolated from a chest wall lesion, transtracheal aspirate, and lung tissue. The other patient presented with a subcutaneous abscess of the left hip that yielded A. meyeri on culture. A localized lung infection and empyema were found. Both patients had other aerobes or anaerobes recovered from material haboring A. meyeri, a frequent finding in actinomycosis caused by Actinomyces israelii. To our knowledge, thoracic actinomycosis caused by A. meyeri has not been previously described.

Empyema thoracis during a ten-year period. Analysis of 72 cases and comparison to a previous study (1952 to 1967).

In this series of 72 cases of empyema, 28 patients (38.8) had anaerobes isolated from their pleural fluid cultures. In 22 patients, anaerobes were the only isolates, and in six there were also aerobes. This observed frequency (38.8%) of anaerobic empyema is notably greater than the frequency noted in an earlier study (1952 to 1967) from the Veterans Administration Medical Center, Wood, Wis, while the contribution of various pathogenetic mechanisms was similar. Although closed chest tube drainage was instituted initially in 51 patients, 18 patients (35%) subsequently required additional procedures. The case-fatality ratio was 51.4% in this study compared with 46.6% in the earlier study. Twenty-two patients died during the same hospitalization period while the empyema was an active problem. Six (8.3%) of these empyema-related deaths occurred in patients without underlying disease, while 16 (22.2%) were in patients with underlying diseases.

Meningococcal pneumonia. A source of nosocomial infection.

Pneumonia apparently resulting from aspiration became clinically apparent in an elderly man two days after admission to a private room on a general medical ward. Pneumonia developed in a patient in an adjacent room three days later. Both patients had group B Neisseria meningitidis isolated from a percutaneous transtracheal aspirate. A prevalence survey failed to identify meningococcal carriers among other ward patients. The index patient required frequent nasotracheal suctioning during the first two hospital days prior to penicillin G potassium therapy. The second patient was simultaneously receiving continuous oxygen therapy administered by nasal cannula. Events suggested that the organism may have been transmitted by direct contact, probably on the hands of hospital personnel.