Rapid disease progression in a patient with mismatch repair-deficient and cortisol secreting adrenocortical carcinoma treated with pembrolizumab.

CONTEXT: Metastatic adrenocortical carcinoma (ACC) is an aggressive malignancy with a poor prognosis and limited therapeutic options. A subset of ACC is due to Lynch syndrome, an inherited tumor syndrome resulting from germline mutations in mismatch repair (MMR) genes. It has been demonstrated that several cancers characterized by MMR deficiency are sensitive to immune checkpoint inhibitors that target PD-1. Here, we provide the first report of PD-1 blockade with pembrolizumab in a patient with Lynch syndrome and progressive cortisol-secreting metastatic ACC. CASE REPORT: A 58-year-old female with known Lynch syndrome presented with severe Cushing's syndrome and was diagnosed with a cortisol-secreting ACC. Three months following surgical resection and adjuvant mitotane therapy the patient developed metastatic disease and persistent hypercortisolemia. She commenced pembrolizumab, but her second cycle was delayed due to a transient transaminitis. Computed tomography performed after 12 weeks and 2 cycles of pembrolizumab administration revealed significant disease progression and treatment was discontinued. After 7 weeks, the patient became jaundiced and soon died due to fulminant liver failure. CONCLUSION: Treatment of MMR-deficient cortisol-secreting ACC with pembrolizumab may be ineffective due to supraphysiological levels of circulating corticosteroids, which may in turn mask severe drug-induced organ damage.

In vitro activity of oral antimicrobial agents against clinical isolates of Pasteurella multocida.

Pasteurella multocida causes a wide variety of infections and is the most common localized soft tissue infection after animal bite injuries. Penicillin or amoxicillin has been considered agent of choice for therapy. Reported beta-lactamase production by some isolates, the therapeutic dilemma of the penicillin allergic patient, and the polymicrobial nature of some infections led to this study of alternate antimicrobial agents. The in vitro activity of ampicillin, amoxicillin/clavulanate, cefprozil, cefuroxime, erythromycin, clarithromycin, trimethoprim/sulfamethoxazole, ciprofloxacin, and tetracycline were compared to penicillin against 73 geographically diverse isolates of P. multocida from human infections collected since 1991. MIC90 (microgram/mL) were as follows: penicillin < or = 0.06; ampicillin < or = 0.5; amoxicillin/clavulanate < or = 0.5; cefaclor 1.0; cefprozil 1.0; cefpodoxime 0.06; cephalothin 2.5; cefuroxime < or = 0.25; erythromycin 2.0; azithromycin 1.0; clarithromycin 4.0; trimethoprim/sulfamethoxazole < or = 0.5/9.5; ciprofloxacin < or 0.25; tetracycline < or = 2.0. No beta-lactamase producing isolates were found in this study. This in vitro study has identified alternate oral agents to penicillins that may be appropriate for therapy of P. multocida infections.

Comparison of five different susceptibility test methods for detecting antimicrobial agent resistance among Haemophilus influenzae isolates.

The detection of antimicrobial agent resistance among ninety-eight Haemophilus influenzae isolates was assessed by six different antibiotic test methods: agar dilution on Mueller-Hinton agar supplemented with 5% lysed horse blood (MH-LHB), E-test using both Haemophilus test medium (HTM) agar and chocolate Mueller-Hinton (CMH) agar plates, Vitek Haemophilus susceptibility cards, and three overnight microdilution systems that included two commercial systems, Micro-Media and MicroScan, and the reference broth microdilution method using HTM broth. Agents tested in the study included ampicillin, amoxicillin/clavulanic acid (A/C), cefaclor, cefuroxime, cefotaxime, ceftriaxone, chloramphenicol, and trimethoprim/sulfamethoxazole. Both the reference HTM microbroth dilution method and agar dilution correctly classified all nine of the beta-lactamase negative ampicillin resistant (BLNAR) isolates. Each of the other test methods failed to detect one of the BLNAR strains, either because of growth failure (Micro-Media and MicroScan) or miscategorization of an isolate as susceptible (E-Test HTM, E-Test CMH, and Vitek). None of the test methods detected all six isolates identified as A/C resistant by HTM microbroth dilution. Of the remaining antimicrobials tested, ampicillin and cefuroxime yielded data that could be compared by all test methods. The very major, major, and minor errors for these two antimicrobials in comparison to the reference HTM microdilution method were as follows: Micro-Media (1.7%, 0%, and 4.8%); MicroScan (11.9%, 0%, and 8.1%); E-Test HTM (1.6%, 0%, and 2.0%); E-Test CMH (1.6%, 1.6%, and 4.6%); Vitek (8.1%, 0%, and 3.1%); and agar dilution on MH-LHB (0%, 0%, and 4.6%). Micro-Media and MicroScan panels failed to support the growth of 4.1% and 5.1% of the isolates, respectively.

Evaluation of Amplicor PCR for direct detection of Mycobacterium tuberculosis from sputum specimens.

We evaluated the Amplicor PCR assay (Roche Molecular Systems, Branchburg, N.J.) for direct detection of Mycobacterium tuberculosis in sputum. A total of 532 specimens from 270 patients were decontaminated and stored at 4 or -75 degrees C until assayed by PCR. This assay used three-step sample preparation, biotinylated primer pairs, AmpErase, and a microtiter format for amplicon capture and detection. Amplicor PCR results were compared with clinical history, culture from a Lowenstein-Jensen slant, and results from the BACTEC TB-460 system. Eighty-seven cultures from 15 patients grew M. tuberculosis; of these, 83 (95%) were positive with the Amplicor PCR test. The false negatives were most likely due to sample variation and inhibitors. Of the 445 specimens from which M. tuberculosis was not isolated, 428 (96%) were negative with the Amplicor PCR test. Of the 17 M. tuberculosis culture-negative, Amplicor-positive specimens, 15 were reclassified as true positives because previous cultures grew M. tuberculosis. Of the 445 specimens which did not grow M. tuberculosis, Mycobacterium spp. other than M. tuberculosis were isolated from 150 specimens. Three of these 150 specimens were Amplicor positive; two were from a patient with a history of tuberculosis, and one specimen gave a false-positive result. We do not feel that this represents cross-reactivity, because repeated Amplicor testing of the isolate gave negative results. The microtiter plate has 96 wells. Allowing for six controls, 90 decontaminated specimens can be tested by one technologist in 7.5 h. This PCR assay took 7.5 h to complete and is a sensitive and specific, rapid method for the direct detection of M. tuberculosis from sputum.

Clinical comparison of the Baxter MicroScan Yeast Identification Panel and the Vitek Yeast Biochemical Card.

To determine the reliability of the Baxter MicroScan Yeast Identification Panel, processed by the Walkaway-96, and the Vitek Yeast Biochemical Card, 150 clinical yeast isolates (30 Candida albicans, 67 Candida species, not albicans, 26 Torulopsis glabrata, 13 Cryptococcus neoformans, 4 Saccharomyces cerevisiae, 6 Trichosporon beigelii, 3 Rhodotorula species, and 1 Geotrichum species) were tested on both systems. Results were compared with those obtained by the API 20C and the appearance of yeast cells on cornmeal Tween-80 agar. After inoculation of each system, results were available in 4 hours with MicroScan panels, 24-48 hours with Vitek cards, and 72 hours with the API 20C strips. On initial testing, 101 (67%) and 128 (85%) isolates, respectively, were correctly identified by MicroScan and Vitek. After repeat testing, the number of correctly identified isolates increased to 123 (82%) by MicroScan and to 142 (95%) by Vitek. Yeasts most commonly misidentified were Candida tropicalis, T glabrata, and Candida parapsilosis by MicroScan and C tropicalis and T glabrata by Vitek.

Comparison of susceptibility test methods to detect penicillin-resistant Streptococcus pneumoniae.

The detection of penicillin-resistant Streptococcus pneumoniae was assessed by six different methods: agar dilution, oxacillin screen by disk diffusion, E-test, and three overnight microdilution test methods that included commercial panels from MicroScan and Micro Media and in-house-made conventional panels using a commercial Haemophilus test medium (HTM) broth. Of the 52 pneumococcal isolates tested, 12 were resistant, 16 were relatively resistant, and 24 were susceptible to penicillin as defined by the reference agar dilution method. The oxacillin screen detected as resistant all 28 resistant and relatively resistant strains. The percentage of penicillin-resistant isolates detected by each minimum inhibitory concentration (MIC) test method was as follows: E-test (100%), Micro Media (75%), MicroScan (0%), and HTM (0%). With the relatively resistant isolates, the detection percentage was as follows: E-test (88%), Micro Media (94%), MicroScan (69%), and HTM (69%). In conclusion, the E-test and Micro Media MIC tests are acceptable confirmatory tests for detecting penicillin resistance among S. pneumoniae isolates.

Group A beta-hemolytic streptococcal bacteremia and intravenous substance abuse. A growing clinical problem?

Over an 18-month period, the incidence of group A beta-hemolytic streptococcal bacteremia rose from an average of 2.5 per 10,000 patient discharges to 17.9. A retrospective analysis was performed comparing patients with group A beta-hemolytic streptococcal bacteremia during this 18-month period with those who presented over the preceding 36 months. Most of the increased incidence was attributable to individuals hospitalized with a diagnosis of drug addiction who had concomitant soft-tissue infection, although the absolute number of hospitalized drug addicts did not change during this interval. No common or distinctive group A streptococcal serotypic patterns were discovered. This experience suggests that group A beta-hemolytic streptococcal bacteremia and soft-tissue infection may present in epidemic fashion among parenteral drug addicts in the absence of a common source.

Comparison of the API Staph-Ident and DMS Staph-Trac systems with conventional methods used for the identification of coagulase-negative staphylococci.

Two commercial kit systems, the API Staph-Ident system (Analytab Products, Inc., Plainview, N.Y.) and the DMS Staph-Trac system (DMS Laboratories, Inc., Flemington, N.J.), were compared with conventional methods for the identification of nine species of coagulase-negative staphylococci. The API Staph-Ident system, a biochemical and chromogenic substrate micromethod, correctly identified 95 of 120 (79.2%) clinical isolates of coagulase-negative staphylococci after 5 h of incubation. The DMS Staph-Trac system, a miniaturized biochemical test system which requires a 24-h incubation period, correctly identified 106 (88.3%) of the same isolates. Both commercial systems were similar in cost and amount of technologist time required to inoculate and read each system. The clinical value of routine species identification of coagulase-negative staphylococci has not yet been established. The decision by clinical laboratories of whether to adopt this practice will be greatly facilitated by the availability of commercial kit systems which are both rapid and accurate.

Mechanism of action of Clostridium perfringens enterotoxin. Effects on membrane permeability and amino acid transport in primary cultures of adult rat hepatocytes.

Purified enterotoxin from the bacterium Clostridium perfringens rapidly decreased the hormonally induced uptake of alpha-aminoisobutyric acid in primary cultures of adult rat hepatocytes. At 5 min after toxin addition the decrease in alpha-aminoisobutyric acid uptake appeared not due to increased passive permeation (estimated with L-glucose) or to increased alpha-aminoisobutyric acid efflux. When short uptake assay times were employed a depression of alpha-aminoisobutyric acid influx was observed in toxin-treated hepatocytes. The depression of alpha-aminoisobutyric acid influx was correlated with a rapid increase in intracellular Na+ (estimated using 22Na+) apparently effected by membrane damage. In contrast, the uptake of cycloleucine in the presence of unlabeled alpha-aminoisobutyric acid (assay for Na+-independent amino acid uptake) by hepatocytes treated with toxin for 5 min was decreased to only a small extent or not at all depending upon experimental design. At later times, C. perfringens enterotoxin increased the exodus of L-glucose, 3-O-methylglucose and alpha-aminoisobutyric acid from pre-loaded cells indicating that the toxin effects progressive membrane damage. When enterotoxin was removed by repeated washing after 5--20 min the decay of alpha-aminoisobutyric acid uptake ceased and appeared to undergo recovery towards the hormonally induced control level. The degree of recovery of alpha-aminoisobutyric acid uptake was inverse to the length of time of exposure to toxin. Adding at 10 min specific rabbit antiserum against C. perfringens enterotoxin without medium change also reversed the effect of toxin on increased intracellular 22Na+, and on the exodus (from preloaded cells) of alpha-aminoisobutyric acid, L-glucose, and 3-O-methylglucose.

Response of mouse liver glycogen cycle enzymes to endotoxin treatment.

The present study was undertaken to characterize endotoxin-induced changes in carbohydrate metabolism and more specifically, to determine the contribution of glycogenolysis to the loss of liver glycogen. Female ICR mice, fasted overnight, were injected with a median lethal dose (LD50, 9 mg/kg) of endotoxin extracted from Salmonella typhimurium strain SR-11. Glycogen synthase and glycogen phosphorylase activities were measured at 0.5 and 6 h after treatment. Endotoxin treatment did not alter total glycogen synthase activity, but the amount of enzyme present in the active form was significantly lower in endotoxic mice. There was no significant increase in glycogen phosphorylase activity in endotoxin-treated mice. Glycogen phosphorylase was activated to the same extent in control and endotoxic mice by decapitation or intravenous epinephrine (25 or 1 mug/kg). The results of this study indicate no significant increase in glycogen phosphorylase activity in endotoxic mice, contraindicating enhanced glycogenolysis as a mechanism for depletion of carbohydrate following endotoxin injection. Altered activation of glycogen synthase, however, may contribute to the loss of glycogen during endotoxemia.