Antibody responses to preS components after immunization of children with low doses of BioHepB.

BioHepB is a recombinant, hepatitis B vaccine derived from a mammalian cell line and containing HBs as well as preS1 and preS2 antigens, in their glycosylated and non-glycosylated forms. The vaccine was administered intramuscularly to 18 children aged 5 months to 11 years at 0, 1 and 6 months. One hundred percent seroconversion and seroprotection rates were achieved after primary and secondary immunization with the 2.5 microg doses of BioHepB. Ten out of the 18 children (56%) responded with the appearance of anti-preS1 and/or anti-preS2 antibodies in circulation, when analyzed 1, 2, 6, 7 and 12 months after the initiation of vaccination. In comparison with the emergence of the anti-HBs response, early (month 2, after two injections) or late (month 7, after three injections) peak responses were noted for the kinetics of anti-preS1 and anti-preS2 production during the course of immunization, demonstrating that the anti-preS1 and anti-preS2 responses are differently regulated, compared with the anti-HBs response. At month 6, just prior to the final injection, BioHepB caused significantly higher anti-HBs responses (GMT) in preS1-reactive children than in children without preS1 antibodies (P<0.005). Moreover, a significantly higher, anti-HBs response in GMT was also noted for anti-preS2-reactive children compared with anti-preS2-negative children (P<0.05). These findings demonstrated that recognition of the preS epitopes contained in the experimental preS1/preS2/S vaccine is accompanied by a more rapid onset and pronounced antibody response to the S-gene-derived protein in healthy children.

Susceptibility of gram-positive bacteria isolated from a paediatric hospital environment to antibiotics.

Susceptibility of Gram-positive bacteria isolated from the hospital environment to antibiotics was determined. About 19% strains were resistant to most tested antibiotics. Among 30 coagulase-negative staphylococci, 8 of them have been found to be resistant to 6-13 antibiotics, whereas among 15 strains of S. aureus only one was resistant to 6 antibiotics. Only gentamicin was effective to all tested Gram-positive strains, whereas ceftazidim, tetracycline and doxycycline were ineffective to the most tested bacteria.

Susceptibility of gram-negative bacteria isolated from a paediatric hospital environment to antibiotics.

The majority of tested Gram-negative strains isolated from the hospital environment were resistant to 6-14 used antibiotics. The greatest resistance was shown by three strains: Enterobacter cloacae, Proteus mirabilis and Ps. maltophilia, which were resistant to all tested drugs. The most effective antibiotic was gentamicin, at least against half of bacteria belonging to Enterobacteriaceae family, to 90% of strains from Pseudomonas genus and to all other Gram-negative rods. Cephtazidim, cephotaxim, colistin and carbenicillin were effective only to 60-70% of Enterobacteriaceae family strains, whereas ampicillin and tetracycline to 70% of Pseudomonas genus. Other Gram-negative bacilli were more susceptible to antibiotics. Cephalothin was ineffective to all tested strains.

The danger of infections of the hospitalized patients with the microorganisms present in preparations and in the hospital environment.

Two strains-S. aureus and coagulase-negative staphylococcus, resistant to antibiotics, were isolated from previously non-opened preparations made by the hospital pharmacy and industrially produced. After application in the surgery ward, two Enterobacter agglomerans strains, resistant to antibiotics were detected in oral mixtures. The resistant bacteria, B. cereus and 4 strains of Ps. aeruginosa, were also found in the purified water. In hospital environment 9 strains of staphylococci, resistant to the tested antibiotics were found. Only one of them was S. aureus (detected on the wall), the others being coagulase-negative staphylococci. Most of them were isolated from the floor, but also from the wall, table and from the air in surgical and ophthalmological wards and in the hospital pharmacy. The most dangerous were three Gram-negative strains resistant to all tested antibiotics. They were isolated from the floor (Enterobacter cloacae), from the wall (Proteus mirabilis) and from the container with oral mixture in infant ward (Ps. malthophilia). Many strains resistant to many antibiotics were detected on the floor of surgical, nephrological and infantile wards as well as from the pharmacies: Enterobacter cloacae (7 strains), Citrobacter freundi, Ps. aeruginosa, Ps. cepacia (2 strains), Ps. maltophilia (2 strains) and Moraxella. Many resistant strains were also present on the walls (E. coli, Ps. mirabilis, Ps. cepacia, Alcaligens, Acinetobacter). The resistant strains were rarely observed on the table, medical equipment and on personnel hands. Klebsiella oxytoca and Ps. paucimobilis were found on the table, Ps. maltophilia on the dropper and on the rim of the container with oral mixture. Acinetobacter and Pseudomonas sp. were isolated from the medicine glass, Enterobacter cloacae and Pseudomonas sp. from the personnel hands in the pharmacies.

Microbial contamination of pharmacies and hospital wards environment and its influence on the purity of prescription preparations during their production process as well as their application.

Microbiological contamination of such environmental factors as air, surfaces of equipment, walls, floors and personnel gloves in two hospital pharmacies and different paediatric hospital wards were tested. Most surfaces in the areas, where the sterile preparations (eye dosage forms) are prepared, turned out to meet the hygienic requirements, although some bacteria belonging to Staphylococci, Pseudomonas, Acinetobacter were detected. The considerable number of microorganisms from 10(2) up to 10(6) cells on 25 cm2 was found on personnel hands and on surfaces of the rooms, where the nonsterile prescription preparations for external and oral use are prepared. Among the identified microorganisms, S. aureus, Enterobacter, Proteus and Moraxella were also observed. However, most opportunistic pathogens like E. coli, Enterobacter, Klebsiella, Citrobacter, Proteus and Ps. aeruginosa were found in the wards in lower numbers (10(0)-10(2). The negative influence of the environment contamination on the purity of prescription preparations, especially during their application in the hospital wards, was observed.

Susceptibility of bacteria isolated from non-parenteral preparations applied in paediatric hospitals to antibiotics.

No strains resistant to all tested antibiotics were found among the 33 Gram-positive and 17 Gram-negative bacteria isolated from non-parenteral drugs and purified water. Three strains: S. aureus, coagulase-negative staphylococcus and B. cereus have been found to be resistant to 6-8 antibiotics, whereas six Gram-negative strains belonging to Enterobacter agglomerans and Ps. aeruginsosa were resistant to 6-12 antibiotics. The most effective agent against all tested Gram-positive bacteria was cephaloridine, and erythromycin against the staphylococci. Tetracycline and ceftazidim were the least effective. Gentamycin was the only antibiotic effective to all Gram-negative strains, and ceftazidim to most of them. Cefsulodin was ineffective to Ps. aeruginosa.

Epidemiology of Pseudomonas aeruginosa infection and the role of contamination of the environment in the Danish Cystic Fibrosis Centre.

In order to identify the possible reservoirs and routes of cross-infection with Pseudomonas aeruginosa, samples were collected during a six-week period in autumn 1992 from patients, their visiting parents, staff and the inanimate environment of the Danish Cystic Fibrosis (CF) Centre and from a control ward with common paediatric diseases. All the P. aeruginosa strains were phage typed and serotyped. From 240 CF patients, 310 strains of P. aeruginosa were isolated, and of these 283 (91.3%) belonged to the polyagglutinable phenotype, most often with a short phage type (31/188 or 109). P. aeruginosa was isolated from only six (0.6%) of 1000 swabs taken from the environment. These six environmental strains and 20 P. aeruginosa strains from CF patients with identical serotype and phage type were examined with pulsed field gel electrophoresis. None of the patients harboured strains similar to the environmental strains, indicating the present isolation procedure and hygienic precautions were effective in our CF centre, and prevented contamination of the environment with P. aeruginosa.