Evaluation of the automated Bact-Alert system for pediatric blood culturing.

The Organon Teknika BacT/Alert (Organon Teknika, Durham, NC), using the Pedi-BacT 20 mL aerobic bottle (BPBCS) was compared to the Wampole Isolator (WI) 1.5 Microbial tube (Wampole Laboratories, Cranbury, NJ), for detection and recovery of pediatric pathogens. The BPBCS continuously monitors culture bottles for changes in CO2 concentrations, while WI cultures are examined twice daily for appearance of colonial growth on agar media. Of 5,175 paired blood cultures, 383 pathogens were recovered from 606 positive cultures. There were 272 pathogens recovered by both systems, 64 from BPBCS only, and 47 from WI only. Overall recovery rates were 88% for BPBCS and 83% for WI. There was no significant difference between the two systems in detection or times to positivity of staphylococci, Enterobacteriaceae, or pseudomonads. Trends toward better recovery of streptococci (20 vs. 10) and fastidious microaerophiles (3 vs. 0) were found with BPBCS, whereas more slowly growing pathogens (Rochalimaea henselae [1], Mycobacterium avium-intracellulare [1]) were recovered by WI only, but because of their lower frequency did not achieve statistical significance. Detection of Haemophilus influenzae (14.9 hours in WI vs. 45.4 hours in BPBCS) was faster with WI. False positive plus contaminant cultures were detected in 5.9% BPBCS versus 1.5% WI. BPBCS offers detection of bacteremia at a rate comparable to WI with advantages of automation.

Invasive pneumococcal disease in central Oklahoma: emergence of high-level penicillin resistance and multiple antibiotic resistance. Pneumococcus Study Group.

Relatively penicillin-resistant pneumococci have caused 10% of invasive pneumococcal disease in central Oklahoma during the last decade, but almost no high-level penicillin or other antibiotic resistance has been described. This study evaluated antibiotic susceptibility and serotype distribution in invasive pneumococcal disease in the Oklahoma City metropolitan area (1990 population 848,000). A total of 144 cases of invasive infection was collected in 1 year (17 with meningitis, 120 with other bacteremic infections, and 7 with other invasive infections), for a rate of 16.9/100,000 (95% confidence interval [CI], 14.0-19.5). For the population aged > or = 60, invasive pneumococcal disease rates were higher among nursing home residents (352/100,000) than among nonresidents (25.6/100,000; relative risk, 13.7; 95% CI, 7.7-24.7). Antibiotic-resistant organisms caused 19.4% of the cases: relative penicillin resistance, 7.6%; high-level penicillin resistance, 1.4% (2 cases), and 11% resistance to erythromycin, trimethoprim-sulfamethoxazole, or both, with 5% sharing both resistances plus a MIC of penicillin of 0.06 microgram/mL.

Bacteremia due to Rochalimaea henselae in a child: practical identification of isolates in the clinical laboratory.

Two closely related species of Rochalimaea, Rochalimaea quintana and Rochalimaea henselae, are nutritionally fastidious but can be cultivated on bacteriologic media from the blood of patients with diverse clinical presentations. We report a case of culture-proven R. henselae bacteremia in a child with persistent fever. Serologic evidence of infection by R. henselae was ascertained by testing sera at two intervals for immunoglobulin G or immunoglobulin M antibodies by enzyme immunoassay and immunoblot. The case isolate and a collection of other strains (R. henselae, R. quintana, and related organisms) were used to test commercial identification systems for their comparative utility in the identification of Rochalimaea spp. on a practical basis. Of six systems designed for testing of either fastidious or anaerobic isolates of bacteria, the MicroScan Rapid Anaerobe Panel was the only system that distinguished R. henselae from R. quintana. Four of five others gave reactions that were unique within their data bases but did not distinguish Rochalimaea isolates at the species level.

A high-resolution record of holocene climate change in speleothem calcite from cold water cave, northeast iowa.

High-precision uranium-thorium mass spectrometric chronology and (18)O-(13)C isotopic analysis of speleothem calcite from Cold Water Cave in northeast Iowa have been used to chart mid-Holocene climate change. Significant shifts in dagger(18)O and dagger(13)C isotopic values coincide with well-documented Holocene vegetation changes. Temperature estimates based on (18)O/(16)O ratios suggest that the climate warmed rapidly by about 3 degrees C at 5900 years before present and then cooled by 4 degrees C at 3600 years before present. Initiation of a gradual increase in dagger(13)C at 5900 years before present suggests that turnover of the forest soil biomass was slow and that equilibrium with prairie vegetation was not attained by 3600 years before present.

Rochalimaea henselae sp. nov., a cause of septicemia, bacillary angiomatosis, and parenchymal bacillary peliosis.

Nine strains of Rochalimaea spp. that were isolated from patients over a period of 4.5 years were characterized for their enzyme activities, cellular fatty acid compositions, and DNA interrelatedness among Rochalimaea spp., Bartonella bacilliformis, and Afipia felis (cat scratch disease bacillus). All except one isolate, which was Rochalimaea quintana, were determined to belong to a newly proposed species, Rochalimaea henselae sp. nov. After recovery from clinical material, colonies required 5 to 15 days of incubation to become apparent. Cells were small, gram-negative, curved bacilli and displayed twitching motility. Enzyme specificities for amino acid and carbohydrate substrates showed that R. henselae could be distinguished from Rochalimaea vinsonii by L-arginyl-L-arginine and L-lysyl-L-alanine peptidases, but not all strains could be distinguished from R. quintana on the basis of peptidases or carbohydrate utilization. R. henselae also closely resembled R. quintana in cellular fatty acid composition, with both consisting mainly of C18:1, C18:0, and C16:0 fatty acids. However, the strains of R. henselae all contained C18:0 in amounts averaging greater than or equal to 22%, in contrast to R. quintana, which contained this cellular fatty acid in amounts averaging 16 and 18%. DNA hybridization confirmed the identification of one clinical isolate as R. quintana and showed a close interrelatedness (92 to 100%) among the other strains. Under optimal conditions for DNA reassociation, R. henselae showed approximately 70% relatedness to R. quintana and approximately 60% relatedness to R. vinsonii. Relatedness with DNA from B. baciliformis was 43%. R. henselae was unrelated to A. felis. R. henselae is the proposed species of a newly recognized member of the family Rickettsiaceae, which is a pathogen that may be encountered in immunocompromised or immunocompetent patients. Prolonged fever with bacteremia or vascular proliferative lesions are clinical manifestations of the agent.

Pneumonia caused by a newly recognized pseudomonad in a child with chronic granulomatous disease.

A pseudomonad was isolated from the pleural fluid and pulmonary decortication tissue of a 5-year-old child with chronic granulomatous disease. Although the isolate was phenotypically similar to Pseudomonas cepacia, its biochemical profile was more similar to that of Pseudomonas pickettii biovar 2. Its slow growth rate, ability to hydrolyze urea rapidly, and lateral and polar flagellar pattern were suggestive of Oligella ureolytica (formerly CDC group IVe). The cellular fatty acid composition was similar to that of P. cepacia and Pseudomonas gladioli, except for the presence of dodecanoic acid. Numerical analysis of the fatty acid data supported the interrelatedness of the isolate with other species of the pseudomallei group (rRNA homology group II) of Pseudomonas. The organism described in this report is an addition to the growing list of catalase-positive organisms which can potentially cause severe morbidity in patients with chronic granulomatous disease.

Aeromonas species in aquaria: a reservoir of gastrointestinal infections?

To assess the role of aquaria in the epidemiology of aeromonas associated gastroenteritis, the prevalence and antibiotic susceptibility of aeromonads in ornamental aquaria were determined and compared to that of isolates obtained from patients with gastroenteritis. Thirty-eight (76%) of 50 aquaria, including those located in our hospital, yielded 61 isolates: 24 (39.3%) Aeromonas sorbria, 18 (29.0%) A. hydrophila, 15 (24.6%) A. caviae, and four (6.5%) which could not be speciated. In comparison, 41 (65%) of 63 faecal isolates were A. caviae. The aquarium isolates, in contrast to enteric isolates, were generally resistant to chloramphenicol, tetracycline, and trimethoprim/sulphamethoxazole. These findings indicate aquaria are unlikely sources of aeromonas-associated gastroenteritis, but their role as possible reservoirs for non-enteric infections with aeromonads needs to be defined.

Aeromonas-associated gastroenteritis in children.

During a 20-month period 55 strains of Aeromonas species were isolated from 53 children with diarrhea. The isolation rate of 2.5% for Aeromonas compared with the rates of 4.5% for Shigella, 3.3% for Salmonella, 2.7% for Campylobacter and 0.05% for Yersinia. In 45 children Aeromonas was the sole bacterial enteropathogen identified. Aeromonas was also isolated from 2 (0.5%) of 380 asymptomatic children. Despite its known lack of identifiable virulence properties, Aeromonas caviae was the most prevalent species, accounting for 69% of the isolates. None of the A. caviae strains produced cytotoxin by the 51Cr release assay and 12.5% were weakly enterotoxigenic by the infant mouse assay. All of the Aeromonas sobria and 71% of Aeromonas hydrophila were positive for both toxins. Ninety-two percent of the children with Aeromonas-associated diarrhea were younger than 3 years; 84% of the cases were seen between May and October. The majority of the children had an acute onset of watery diarrhea. Fever and vomiting were most commonly associated with the isolation of A. sobria. Eight children had chronic or intermittent diarrhea lasting for weeks to months before consultation; A. caviae was the isolate in all these cases. Several complications possibly related to Aeromonas intestinal infection were observed. These included Gram-negative bacteremia, intussusception, internal hernia strangulation, hemolytic uremic syndrome and failure to thrive in patients with chronic diarrhea.

Antimicrobial susceptibility of Aeromonas species isolated from patients with diarrhea.

In vitro susceptibility to 17 antimicrobial agents was determined for Aeromonas caviae, A. hydrophila, and A. sobria isolated from feces of patients with diarrhea. The three Aeromonas species shared a similar susceptibility pattern, except to cephalothin. Of the oral antimicrobial agents, the quinolones, followed by chloramphenicol, were most active; trimethoprim-sulfamethoxazole and tetracycline had good but variable activity.

Recognition of Staphylococcus saprophyticus in urine cultures by screening colonies for production of phosphatase.

Phenolphthalein diphosphate was incorporated into a primary blood agar medium for use in performing quantitative urine cultures. Phosphatase-negative staphylococci, such as Staphylococcus saprophyticus, were differentiated from phosphatase-positive species, such as Staphylococcus epidermidis, by spot testing colonies on filter paper saturated with 1 N NaOH. Phosphatase-positive colonies turned pink within seconds, and phosphatase-negative colonies showed no color. None of 55 S. saprophyticus isolates showed production of phosphatase on this medium. Of 193 consecutive coagulase-negative staphylococci isolated from the urine of 190 adolescent female patients, 84% were phosphatase positive, non-S. saprophyticus species; 16% were phosphatase-negative and indicated S. saprophyticus (22), Staphylococcus haemolyticus (4), Staphylococcus simulans (2), Staphylococcus warneri (1), and Staphylococcus hominis (1). Phosphatase activity was variable in the other flora encountered in the urine cultures. Mixtures of phosphatase-positive and -negative organisms did not cause false-positive reactions.