Comparative study of three different BACTEC culture media for the detection of bacteremia in ambulatory and hospitalized children.

To compare the yield of two aerobic and an anaerobic BACTEC blood culture media in detecting bacteremia in ambulatory and hospitalized care settings at a children's hospital, a prospective cohort study was completed. Over an 18-month period, equal blood volumes (minimum of 1 mL/bottle) were inoculated into a three-bottle culture set including aerobic BACTEC NR 6A, aerobic BACTEC PEDS Plus and anaerobic NR 7A broths. Chart reviews were completed on all children with bacteremia to determine whether the isolate was clinically significant based on predefined criteria. Among 5328 evaluable blood culture sets, 323 clinically significant organisms (110 from ambulatory and 213 from hospitalized children) were isolated. Most Streptococcus pneumoniae, Haemophilus species, and Neisseria or Moraxella species were recovered from children attending the emergency department or out-patient clinics. Important isolates in hospitalized children included most of the staphylococci and Enterobacteriaceae, and all group D enterococci, Gram-negative nonfermentative bacilli and all Candida species. Overall, significantly more isolates were detected only in the anaerobic bottle from ambulatory children (P<0.0001), including 13 of 54 (24%) patients with S pneumoniae bacteremias presenting to the emergency department. This study indicated that different BACTEC blood culture media combinations are needed in ambulatory and hospitalized pediatric care settings to ensure the optimal recovery of all types of isolates. Whereas aerobic blood culture bottles are adequate for detection of bacteremia in hospitalized children, the common occurrence of fastidious organisms mandates the need for a combined aerobic/anaerobic culture set in ambulatory pediatric care settings.

Practice guidelines for ordering stool ova and parasite testing in a pediatric population. The Alberta Children's Hospital.

A comprehensive utilization review was done of all stool ova parasite examinations performed at a pediatric hospital during a 3-year period from June 1, 1989 to July 1, 1992. A total of 2,652 stool specimens were surveyed from 1,532 children. Forty-one percent (1,081) of the workload was from inpatients, 37% (976) was from emergency room (ER) visits/other outpatients, and 22% (233) was from patients attending the gastroenterology (GI) clinic. The prevalence of enteric parasites in hospitalized children was 4% (35 of 829) compared to rates of 10% (47 of 470) and 13% (30 of 233) for children attending the ER/other outpatient clinics and GI clinic, respectively. Giardia lamblia was found most often (31%[45 of 146]), followed by Dientamoeba fragilis (23%[33 of 146]), Entamoeba coli (16%[24 of 146]), Blastocystis hominis (13% [19 of 146]), Cryptosporidium (8% [12 of 146]), Endolimax nana (4% [6 of 146]), Enterobius vermicularis (2% [3 of 146]), Hymenolepis nana (2% [3 of 146]), and Iodamoeba buetschlii (1% [1 of 146]). Most children were colonized/infected with a single parasite (85%) with a much smaller number having two or more parasites. Only nine children (6%) who were immunocompetent and hospitalized for more than 4 days were found to have enteric parasites. Over the past 18 months, significant sustainable cost savings have resulted from the implementation of practice guidelines for ordering pediatric stool ova and parasite examinations.

Practice guidelines for ordering stool cultures in a pediatric population. Alberta Children's Hospital, Calgary, Alberta, Canada.

A comprehensive utilization review was done of all stool culture tests performed at a pediatric hospital during a 3-year period from June 1, 1989 through to July 1, 1992. A total of 4,460 stool culture specimens were surveyed from 3,420 children. Sixty percent (2,692) of the workload was from inpatients, 22% (1,001) was from emergency room (ER) visits and 18% (767) was from outpatient clinic/office visits. A total of 9% (294 of 3,420) of the children were confirmed to have enteric bacterial infection. Enteric infections in Southern Alberta follow a typical pattern, where most cases of Escherichia coli O157:H7, Salmonella sp and Campylobacter jejuni are diagnosed in the summer months between June and September. Marked differences were found in the overall stool culture positivity rate between hospitalized children (94 of 2,141, 4%), and ambulatory children attending the ER (176 of 892, 19%). Although a significant number of children had more than one stool culture done, most cases of enteric bacterial infections were diagnosed on the first stool sample (290 of 294, 98%). Most children (89 of 94, 95%) who were hospitalized because of an acute diarrheal illness had a bacteriological diagnosis confirmed within the first 4 days after admission (90 of 94, 96%), including immunocompromised children in the Oncology ward. Over the past year, significant sustainable cost savings have resulted from the implementation of practice guidelines for ordering pediatric stool cultures.

Transient in vivo selection of a constitutively cephalosporin resistant Enterobacter cloacae causing ventriculitis.

A case of neonatal ventriculitis complicating a ventriculoperitoneal shunt and caused by one strain of Enterobacter cloacae (as shown on pulsed field gel electrophoresis) is presented. Daily ventricular fluid cultures from day 1 to 9 revealed inducible cephalosporin resistance in all isolates except on days 3, 4 and 5 of therapy when isolates were constitutively resistant. This emergence of resistance due to constitutive Bush class 1 beta-lactamase production is an excellent example of the rapid emergence of a predominant strain of bacteria depending on antibiotic selection pressures in vivo. The transient nature of the predominant resistant phenotype may have been due to missing a dose of cefotaxime on day 5 or in vivo factors allowing persistence of sensitive organisms in antibiotic protected sites. Caution is advised in the use of cephalosporins alone for serious Enterobacter species infections. Repeat culture and sensitivity should be done in severe infections that are slow to respond to cephalosporin therapy.

Bacteriuria in intermittent catheterization users: the effect of sterile versus clean reused catheters.

Monthly urine cultures were analyzed at the University of Alberta Department of Medical Microbiology and Infectious Diseases to determine whether single-use sterile catheters and clean technique reduced the incidence of bacterial colonization in those using long-term intermittent self-catheterization. Thirty subjects with spina bifida, ages 3 years to 16 years, entered a crossover study with random assignment to 6 months of sterile single-use catheters or clean reused catheters. Seventeen subjects were catheterized by a parent or caregiver; 13 were responsible for self-catheterization and cleaning of the catheters. Six months of descriptive data were also collected at Alberta Children's Hospital from a similar group of subjects with spina bifida who used sterile catheters only. In the crossover group, 38% of all urine cultures were positive regardless of whether sterile single-use or clean reused catheters were employed. The other group using only sterile catheters had a 36% positive culture rate. No difference in positive cultures was found between males and females or between children who catheterized themselves and children whose parents catheterized them. The authors concluded that plastic urethral catheters may be reused.

Meningitis due to ampicillin-and chloramphenicol-resistant Haemophilus influenzae type b in Canada. Case report and review.

The first report of a case of ampicillin- and chloramphenicol-resistant Haemophilus influenzae type b invasive infection in Canada is described in a four-month-old male with meningitis. He was treated with cefotaxime 200 mg/kg/day divided every 6 h and dexamethasone 0.6 mg/kg/day divided every 6 h, eventually recovering after a complicated course. Follow-up at 21 months showed mild to moderate global developmental delay. While chloramphenicol resistance is rare in North America, a case of meningitis initially unresponsive to ampicillin and chloramphenicol must be considered suspect for resistance. Third generation cephalosporins should be used for resistant cases.