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Coagulase-positive staphylococci have been isolated from more than 95% of cases of toxic shock syndrome (TSS). Toxic shock syndrome toxin-1 (TSST-1) is produced in more than 90% of cases. A case is described of recurrent TSS in which a coagulase-negative staphylococcus was isolated from the vagina and produced TSST-1. No coagulase-positive staphylococci were isolated. Coagulase-negative staphylococci should be considered as causative agents in cases of TSS. Assay for TSST-1 should be performed on coagulase-negative staphylococci obtained from the appropriate clinical sites if no coagulase-positive staphylococci are isolated.

We compared the antimicrobial susceptibility results obtained with the Cathra replicator and reference methods when Staphylococcus aureus strains were tested by using agar dilution techniques. The Cathra replicator and the 0.001-ml calibrated loop gave results that fell within +/- 1 log2 dilution for greater than or equal to 95% of isolates when methicillin and cefamandole were tested.

A 24-year-old man from rural Mississippi had a case of California encephalitis (CE) that evolved as a subacute encephalomyelitis. The incidence of CE in adults is low, especially in the southeastern United States, and to our knowledge the clinical profile of symptomatic disease in adults has not been established. The characteristics of CE and St Louis encephalitis, the usual cause of arboviral illness affecting adults in the Southeast, differ.

While Branhamella catarrhalis is now recognized as an important pathogen, this is only the fifth reported case of endocarditis caused by it. The production of beta-lactamase by many strains and its resistance to vancomycin and clindamycin complicate the choice of antibiotic therapy.

During a 3 1/2-year period (January 1978 through June 1981), 245 patients in a university hospital became colonized or infected with methicillin-resistant Staphylococcus aureus. During the first 18 months, the incidence of colonization and infection was only 0.05%. After a focal outbreak of methicillin-resistant S aureus in the burn unit, acquisition of the organism by patients on other wards increased significantly. Nonburn patients acquired the organism more often during time periods when newly admitted burn patients acquired methicillin-resistant S aureus. After the burn unit was closed, acquisition of the organism among nonburn patients on adult surgical and medical services decreased significantly. A questionnaire survey of other institutions disclosed that large outbreaks of this infection occurred more frequently in hospitals with burn units. These studies suggest that the occurrence of methicillin-resistant S aureus infections in burn units may lead to increased transmission of the organism to nonburn patients and that control of the infection in such units may reduce spread of the organism to patients without burns.

Cultures of blood drawn through indwelling intravascular venous and arterial cannulas were compared with those of blood drawn simultaneously by percutaneous venipuncture. In 92% of 174 comparisons, the results were identical. Cultures of blood drawn through indwelling intravascular catheters are as reliable as those of percutaneously obtained samples. In addition, the speed, ease, and lack of trauma in obtaining blood for cultures in critically ill patients further recommends this technique.

This study was designed to determine if lidocaine inhibited growth of Blastomyces dermatitidis and thereby reduced recovery of the fungus from bronchoscopy specimens. Case records of 36 patients with pulmonary blastomycosis showed that when the fungus was present at microscopy, whether the specimen was sputum or bronchial washings, culture of the bronchoscopic specimen was more frequently negative than the culture of the sputum specimen (p less than .05). In addition, lidocaine was shown to inhibit growth of B dermatitidis in vitro, with the inhibition depending on the concentration of the drug and the duration of exposure (p less than .01). High concentrations of lidocaine for topical anesthesia appear to adversely affect the recovery of B dermatitidis from bronchoscopic specimens.

Electron microscopic examination of yeasts of Blastomyces dermatitidis, exposed in vitro to concentrations of lidocaine that occur when the drug is used for topical anesthesia, showed that lidocaine rapidly damaged intracellular structures. The extent of damage was dependent on the concentration of drug and length of exposure. The observed ultrastructural changes were very similar to those reported for other drugs that directly damage membranes. This relationship suggests that the antifungal effect of lidocaine is the result of direct membrane damage.

The MS-2 system (Abbott Diagnostics, Division of Abbott Laboratories, Dallas, Tex.) is an automated system capable of rapid antimicrobial susceptibility testing. However, the short incubation periods used by the device may adversely affect its ability to detect slowly growing resistant organisms. Shortly after the introduction of the MS-2 system into the University of Mississippi Medical Center clinical microbiology laboratory, we noted discrepancies between the MS-2 and the disk diffusion susceptibility reports when methicillin-resistant Staphylococcus aureus isolates were tested. Subsequently, we determined the susceptibilities of 75 such isolates by the MS-2 and Kirby-Bauer disk diffusion methods and measured the minimum inhibitory concentrations of methicillin, oxacillin, and cephalothin for 33 of the 75 isolates by standardized agar dilution techniques. There was only 47% overall agreement between the MS-2 and disk diffusion methods when methicillin was tested and 15% agreement when cephalothin was the test drug. There was 93% or more overall agreement between the two methods when other antimicrobial agents were tested. The minimum inhibitory concentration of methicillin was greater than or equal to 16 micrograms/ml for all 33 isolates evaluated by the agar dilution method. A comparison of the MS-2 and agar dilution results revealed an overall agreement of 49% when the susceptibilities to methicillin were determined. The MS-2 system reported that multiple methicillin-resistant S. aureus isolates obtained from a single patient were either resistant, intermediate, or sensitive to methicillin. Inconsistent results were also obtained when a single isolate was tested simultaneously in 10 cuvette cartridges. We conclude that the MS-2 system does not reliably detect methicillin and cephalothin resistance among S. aureus.

After closed reduction and casting of a tibial fracture in a 69-year-old diabetic man, a gangrenous lesion developed under the cast. Cultures of debrided tissue revealed multiple bacteria, including Bacillus sp, plus two fungi, Fusarium sp and a zygomycete identified as Cunninghamella bertholletiae. Large nonseptate hyphae in thrombosed blood vessels suggested that C bertholletiae played a major role in the development of the infection. Recovery of organisms from our patient's wound and from the cast padding suggests that the wound infection was acquired from nonsterile dressings.

A patient with multiple subcutaneous abscesses was found to have disseminated actinomycosis. No predisposing cause was identified. No defects in immunity were found. His disease responded promptly to penicillin therapy.

The records of 108 patients treated for bacterial endocarditis were reviewed. Six were diagnosed at autopsy and had not been treated for endocarditis. Of the 102 treated patients, 32 died during the first 30 days and 32 more were dead by 365 days. Although some reports indicate a much greater survival rate, our findings are more in keeping with those reports giving a rather poor long-term outlook for patients with endocarditis.

Diet-induced ultrastructural changes that occur in the atrial wall prior to thrombus formation are atrial subendothelial edema, endothelial vacuoles, damaged basement membrane and villous projections from endothelial (luminal surface) cells. Upon the return to a normal diet for 1-4 weeks, atrial edema is completely reversible, while the other ultrastructural alterations show minor or no signs of being repaired.

The in vitro susceptibilities of 150 clinical isolates of Pseudomonas aeruginosa to the aminoglycoside tobramycin and eight other antimicrobials were evaluated. The Food and Drug Administration standardized disk diffusion method showed that tobramycin inhibited 100% of the 150 isolates with gentamicin inhibiting only 90.7%. The difference between colistin (97.3%) and tobramycin was less marked. Carbenicillin (87.3%) was found to be slightly less active than gentamicin. Only a small percentage of the isolates were inhibited by the other drugs used. By using a minimal inhibitory concentration of 4 mug/ml in brain heart infusion broth as the level of susceptibility, it was found that only three of the isolates showed resistance to tobramycin, whereas 20 of the isolates were resistant to gentamicin. Approximately half of the isolates were inhibited by 0.5 mug/ml or less of tobramycin, whereas 1.5 mug of gentamicin per ml was required to inhibit 50% of susceptible strains.

The serum half-life of tobramycin was found to be the same as that of gentamicin in patients with similar renal function. The values ranged from 2 hr in normal volunteers to 53.4 hr in anephric patients. Both drugs were readily removed from the serum by the Kiil artificial kidney, with a 70% reduction in serum concentrations during a 12-hr dialysis period.