Rapid commercial test for direct detection of group A streptococci in throat swabs.

The Hybritech Strep A ICON was used for direct testing of 1016 throat specimens for group A beta-hemolytic streptococci. Both the test and culture were negative in 829 specimens (81.6%); both were positive in 164 cases (16.1%); the test was positive and culture negative in 9 cases (0.9%); and the test negative and culture positive in 14 cases (1.4%).

Manifestations of Kingella kingae infections in adults: resemblance to neisserial infections.

Kingella kingae is a rare human pathogen. Most reported infections are in children and involve endocardium, vascular space, and skeletal tissues. We report herein two cases of K. kingae infection recently seen in adults. Kingella kingae caused acute meningitis in a patient with sickle cell anemia and in the second patient with alcoholic liver disease, sepsis with a petechial rash. The clinical presentation due to K. kingae closely resembled that caused by related Neisseria genus.

Suppurative lymphadenitis with Yersinia enterocolitica.

Extraintestinal suppurative complications of Yersinia enterocolitica infections are rarely observed. Two cases of suppurative lymphadenitis due to Yersinia enterocolitica are reported which mimicked other, more common disorders.

Studies on the epidemiology of colitis due to Clostridium difficile in hamsters.

Hamsters treated with vancomycin developed enterocolitis significantly more often in a conventional animal room than in a room designed to prevent cross-infection with Clostridium difficile. In the conventional room C. difficile was isolated from cages, food racks, floors, buckets, the hands of caretakers, and the stools of animals with enterocolitis but not from untreated hamsters, air, or food from freshly opened bags. C. difficile was not isolated from environmental sources in the clean room. It was not possible to determine which of the sources of the organism was most important in its spread. Cross-infection with C. difficile may be important in the pathogenesis of antibiotic-associated enterocolitis in hamster colonies.

Studies on the epidemiology of antibiotic-associated Clostridium difficile colitis.

Vancomycin protects hamsters from the development of Clostridium difficile colitis after treatment with clindamycin, and vancomycin is useful in treatment of humans with the disease. Relapses have occurred in both hamsters and humans when vancomycin is discontinued. Vancomycin appears to enhance susceptibility to colonization with C. difficile by eliminating competing intestinal organisms. The nature of these organisms is not known, but various tools are now available to aid in identifying them. Cancer chemotherapeutic agents should be added to the list of factors such as surgery and antibiotics that may predispose to emergence of C. difficile. The number of organisms required for colonization of antibiotic-treated hamsters is low and cross-infection seems to play a role in the disease in hamster colonies. The organism can be detected on surfaces in rooms of patients with the disease, and on the hands of personnel caring for them. Outbreaks of the disease have been recognized. Our results suggest isolation precautions should be used to prevent spread of the organism from patients with the disease to others being treated with antibiotics.

Etiology of tetracycline-associated pseudomembranous colitis in hamsters.

Tetracyclines were implicated in the 1950s in induction of protracted diarrhea and pseudomembranous colitis. Because the pathogenetic mechanism of these illnesses has been questioned recently, we studied tetracycline in hamster models of antibiotic-associated colitis. Orogastric administration of tetracycline caused diarrhea and death, with evidence of hemorrhagic typhlitis. Filtrates of cecal contents were toxic when inoculated into normal hamsters and cell culture monolayers, and toxicity was neutralized with Clostridium sordellii antitoxin. Tetracycline-resistant C. difficile was cultured from stools of these hamsters, but Staphylococcus aureus was not isolated. The value of tetracycline for treatment or prevention of clindamycin-induced colitis in hamsters was also studied, and it was found that daily orogastric administration of tetracycline was poorly protective against clindamycin-induced colitis.

Antibiotic-associated colitis: effects of antibiotics on Clostridium difficile and the disease in hamsters.

Fifteen isolates of Clostridium difficile from hamsters and human patients were inhibited or killed by low concentrations of metronidazole, vancomycin, penicillin, and ampicillin; the isolates were often reesistant to tetracycline, cephalosporins, trimethoprim-sulfamethoxazole, clindamycin, erythromycin, and aminoglycosides. Antibiotics to which C. difficile was susceptible were able to prevent or postpone the colitis caused by clindamycin in hamsters. Colitis could be produced by treatment of hamsters with any one of these antibiotics. Production of colitis not only involved selection of resistant variants, but in some instances seemed to result from the acquisition of organisms after treatment, their persistence despite treatment, or from subinhibitory cecal concentrations of antibiotic (explainable by either pharmacologic factors or enzymatic inactivation). As in humans, no organisms other than C. difficile have been implicated conclusively as etiologic agents of colitis in hamsters. Our results suggest it may be wise to use isolation precautions for patients with colitis caused by C. difficile.