Corynebacterium pseudodiphtheriticum has been reported to be an uncommon respiratory pathogen. We describe the clinical and microbiologic features of 17 patients from whose sputum C. pseudodiphtheriticum was isolated. Patients were identified through a review of the reports from the clinical microbiology laboratory at York Hospital, a community teaching hospital, from October 1990 through April 1993; 17 patients with respiratory infection caused by C. pseudodiphthriticum were identified. There were 12 cases of bronchitis and five of pneumonia. An underlying systemic condition, particularly congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, or malignancy, was common. Onset of symptomatology was acute for most patients, but fever was noticeably absent in almost two-thirds of the cases. Isolates were uniformly susceptible to the beta-lactam antibiotics, vancomycin, and trimethoprim-sulfamethoxazole, but resistance to clindamycin and erythromycin was common. The isolation of diphtheroids from a properly obtained sputum sample from a patient with respiratory tract infection should not always be dismissed as due to contamination. The isolation, identification, and susceptibility testing of C. pseudodiphtheriticum from respiratory tract specimens may provide information useful for treatment of patients.

A single blood culture inoculated with a small volume of blood is still frequently being used for the diagnosis of bacteremia in children because of the continued belief by many that bacteria are usually found in high concentrations in the blood of pediatric patients with sepsis. To determine the importance of both blood volume cultured and the number of culture devices required for the reliable detection of pathogens in our pediatric population, blood from children from birth to 15 years of age and with suspected bacteremia at York Hospital (a 500-bed community hospital) was inoculated into at least a Pediatric Isolator (Wampole Laboratories; 1.5 ml of blood) or a standard Isolator (10 ml of blood) and a bottle of ESP anaerobic broth (Trek Diagnostic Systems; 0.5 to 10 ml of blood). The use of a second Isolator and additional aerobic and anaerobic bottles and the total blood volume recommended for cultures (2 to 60 ml) depended on the weight and total blood volume of each patient. One hundred forty-seven pathogens were recovered from the blood of 137 (3.6%) of 3,829 children for whom culturing was done. Of 121 septic episodes for which the concentration of pathogens in the blood could be determined using Isolators, 73 (60.3%) represented low-level bacteremia (<10 CFU/ml of blood), including 28 pathogens (23.1%) which were detected at concentrations of only <1.0 CFU/ml. Of 144 septic episodes for which two or more culture devices (Isolators and/or bottles) were inoculated, 85 (59%) were associated with false-negative results from one or more of the culture devices. Of the 128 children for whom antibiotic therapy records were complete, therapy was either started or changed for 88 (68.8%) following notification of positive blood cultures. Low-level bacteremia was common in our pediatric population, requiring the culturing of up to 4 or 4.5% of a patient's total blood volume for the reliable detection of pathogens and appropriate, timely changes in empiric therapy.

A single blood culture inoculated with a small volume of blood is still frequently being used for the diagnosis of bacteremia in children because of the continued belief by many that bacteria are usually found in high concentrations in the blood of pediatric patients with sepsis. To determine the importance of both blood volume cultured and the number of culture devices required for the reliable detection of pathogens in our pediatric population, blood from children from birth to 15 years of age and with suspected bacteremia at York Hospital (a 500-bed community hospital) was inoculated into at least a Pediatric Isolator (Wampole Laboratories; 1.5 ml of blood) or a standard Isolator (10 ml of blood) and a bottle of ESP anaerobic broth (Trek Diagnostic Systems; 0.5 to 10 ml of blood). The use of a second Isolator and additional aerobic and anaerobic bottles and the total blood volume recommended for cultures (2 to 60 ml) depended on the weight and total blood volume of each patient. One hundred forty-seven pathogens were recovered from the blood of 137 (3.6%) of 3,829 children for whom culturing was done. Of 121 septic episodes for which the concentration of pathogens in the blood could be determined using Isolators, 73 (60.3%) represented low-level bacteremia (<10 CFU/ml of blood), including 28 pathogens (23.1%) which were detected at concentrations of only <1.0 CFU/ml. Of 144 septic episodes for which two or more culture devices (Isolators and/or bottles) were inoculated, 85 (59%) were associated with false-negative results from one or more of the culture devices. Of the 128 children for whom antibiotic therapy records were complete, therapy was either started or changed for 88 (68.8%) following notification of positive blood cultures. Low-level bacteremia was common in our pediatric population, requiring the culturing of up to 4 or 4.5% of a patient's total blood volume for the reliable detection of pathogens and appropriate, timely changes in empiric therapy.

The efficiency of the 10-ml Isolator (E. I. du Pont de Nemours & Co., Inc.) for recovery of pathogens from blood was compared with that of BACTEC 6B and 7C media (Johnston Laboratories) by using 4,195 cultures from 1,662 patients. During the first phase of the study, BACTEC bottles were inoculated with 3 ml of blood; in the second phase, bottles were inoculated with 5 ml. The objectives were to compare results with similar blood volumes used for the detection of anaerobes as well as similar overall volumes and to determine the relative sensitivity of BACTEC media inoculated with the minimum and maximum volumes suggested by the manufacturer. From 180 patients, 391 significant isolates were recovered, 354 (91%) with the Isolator and 304 (78%) with the bottles. Isolators recovered 31 (15%) and 19 (18%) more pathogens overall than did the two-bottle system inoculated with 3 and 5 ml of blood, respectively, including 30 (36%) and 10 (34%) more Enterobacteriaceae. Recovery of anaerobes was greater in the BACTEC anaerobic medium, but only when its inoculum was increased to 5 ml. No significant differences existed between the two systems in pathogen detection times or detection of polymicrobic bacteremia. The Isolator contamination rate (8.3%) was approximately 4 times that of the bottles. The number of CFU of pathogen per milliliter of blood, blood volume sampled, and number of Isolators collected were more important than antimicrobial agent pretreatment in contributing to patient bacteremia of fungemia undetected by the Isolator. The Isolator appeared to be a practical alternative for recovery of aerobic and facultatively anaerobic pathogens from the blood.

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