Rimma Melamed

Reduction of pneumococcal nasopharyngeal carriage in early infancy after immunization with tetravalent pneumococcal vaccines conjugated to either tetanus toxoid or diphtheria toxoid

BACKGROUND Pneumococcal nasopharyngeal colonization is important for transmission of the organisms. We assessed the ability of two tetravalent conjugate vaccines administered in early infancy to prevent carriage of vaccine-related pneumococci. METHODS A vaccine containing pneumococcal type 6B, 14, 19F and 23F polysaccharide conjugated to tetanus toxoid (Pnc-T) and a vaccine containing the same four polysaccharides conjugated to diphtheria toxoid (Pnc-D) were compared with placebo, in a double blinded study (25 infants per group). Vaccines (or placebo) were injected at 2, 4 and 6 months of age. At 12 months of age a native (nonconjugate) polysaccharide vaccine was administered as a booster. Serum type-specific anticapsular antibody concentrations were measured and nasopharyngeal cultures were obtained at 2, 4, 6, 7, 12 and 13 months of age. RESULTS In general carriage of all pneumococci (vaccine- and non-vaccine-related) was low at age 2 months and increased with age. However, for the vaccine-related serotypes (6A, 6B, 14, 19F and 23F) carriage was not increased with age in Pnc-D or Pnc-T recipients. Of all cultures obtained after the full primary series, 7 of 72 (10%), 3 of 62 (5%) and 19 or 70 (27%) were positive for the vaccine-related pneumococcal serotypes among the Pnc-D, Pnc-T and placebo recipients, respectively (P = 0.001 for Pnc-D vs. placebo; P = 0.014 for Pnc-T vs. placebo). Most of the antibiotic-resistant isolates belonged to the vaccine-related serotypes. CONCLUSIONS A significant reduction in the carriage of vaccine-related strains after administration of conjugate vaccines was observed. These preliminary results suggest that transmission of specific pneumococcal serotypes most often associated with disease and antibiotic resistance may at least partially be controlled by immunization.

Safety and immunogenicity of tetravalent pneumococcal vaccines containing 6b, 14, 19f and 23f polysaccharides conjugated to either tetanus toxoid or diphtheria toxoid in young infants and their boosterability by native polysaccharide antigens

BACKGROUND New vaccines against pneumococcal infections in infancy are needed. We assessed in young infants the safety and immunogenicity of two tetravalent vaccines containing pneumococcal 6B, 14, 19F and 23F polysaccharides conjugated to either tetanus toxoid (Pnc-T) or diphtheria toxoid (Pnc-D). METHODS Pnc-T or Pnc-D containing 3 microg of polysaccharide of each of the four pneumococcal polysaccharides or placebo were given intramuscularly in a double blinded fashion (25 infants per group) at 2, 4 and 6 months of age. At 12 months of age all 75 children were boosted with a 23-valent nonconjugate polysaccharide pneumococcal vaccine. Serum type-specific anticapsular antibody concentrations were measured at 2, 4, 6, 7, 12 and 13 months of age. Adverse events occurring within 72 h after each injection were recorded. RESULTS Both Pnc-T and Pnc-D were well-tolerated. Pnc-T and Pnc-D had higher antibody concentrations compared with placebo after primary immunity (type 6B, 1.66, 1.40 and 0.60 microg/ml, respectively; type 14, 4.81, 2.65 and 2.22 microg/ml, respectively; type 19F, 2.40, 3.48 and 0.83 microg/ml, respectively; type 23F, 0.96, 0.44 and 0.35 microg/ml, respectively). Proportions of infants with concentrations above 1.0 microg/ml were also higher in the vaccine recipients than in those given placebo. After booster with the nonconjugate polysaccharide vaccine, both geometric antibody concentration and proportion with concentrations > or =1.0 microg/ml were significantly higher among either Pnc-T or Pnc-D recipients than among placebo recipients. CONCLUSIONS Both Pnc-T and Pnc-D were well-tolerated, induced serotype-specific anticapsular antibodies and induced immunologic memory.

Safety and immunogenicity of a combined pentavalent diphtheria, tetanus, acellular pertussis, inactivated poliovirus and Haemophilus influenzae type b-tetanus conjugate vaccine in infants, compared with a whole cell pertussis pentavalent vaccine.

BACKGROUND We compared the safety and immunogenicity of two combined diphtheria-tetanus-pertussis-inactivated poliovirus vaccines containing either acellular (Pa, SmithKline Beecham Biologicals) or whole cell (Pw, Pasteur Merieux Connaught) pertussis components, mixed with a Haemophilus influenzae type b polysaccharide polyribosylribitol phosphate-tetanus conjugate vaccine in an open, randomized study in healthy infants. DESIGN The combined vaccines were given at 2, 4, 6 and 12 months of age, and serum samples were obtained at ages 2, 6, 7, 12 and 13 months. Adverse events were obtained by diary cards. RESULTS The Pa group (n = 101) had a clearly lower incidence of both local and systemic adverse events than the Pw group (n = 100). Immunogenicity was comparable for the diphtheria and tetanus components, but significantly superior for pertussis toxin, filamentous hemagglutinin, pertactin and polioviruses 1, 2 and 3 in the Pa group. Both groups had an appropriate response with regard to H. influenzae type b polysaccharide polyribosylribitol phosphate, but the dynamics of the response were significantly different: geometric mean concentrations (micrograms per ml) after the second, third and booster doses were 1.27, 5.06 and 23.12 in the Pa group and 2.72, 6.66 and 13.59 in the Pw group, respectively (P = 0.0002 after second dose; P = 0.0005 after booster). CONCLUSION The presently studied diphtheria, tetanus, acellular pertussis-H. influenzae b vaccine conjugated to tetanus toxoid combination was at least as immunogenic as the diphtheria, tetanus, whole cell pertussis-H. influenzae b vaccine conjugated to tetanus toxoid combination, with a significantly better safety profile. This is of obvious importance in countries where inactivated poliovirus vaccine is part of the routine infant immunization programs.

Interleukin-12 Receptor β1 Deficiency Presenting as Recurrent Salmonella Infection

We describe a child with interleukin-12 receptor beta1 (IL-12Rbeta1) deficiency caused by a homozygous IL12RB1 large deletion who presented at the age of 1 year with recurrent, often asymptomatic episodes of bacteremia caused by group D Salmonella species. No mycobacterial disease or other unusual infection was present. The episodes of salmonellosis were caused by an identical serovar during a period of 18 months. This is the first case of inherited IL-12Rbeta1 deficiency diagnosed after isolated, recurrent salmonellosis.

Immunogenicity and safety of a liquid combination of DT-PRP-T vs lyophilized PRP-T reconstituted with DTP

The immunogenicity and safety of a combined diphtheria, tetanus, pertussis and Haemophilus influenzae type b-tetanus conjugate vaccine (DTP-PRP-T) was compared to the same combination obtained by the reconstitution of H. influenzae type b-tetanus conjugate vaccine lyophilized (PRP-T) with liquid diphtheria-tetanus-pertussis vaccine (DTP). Two hundred and sixty-two healthy infants were randomized to receive a intramuscular injection of 0.5 ml of one of the above combination vaccines at 2, 4 and 6 months of age, and a subgroup of 134 infants received a booster dose at 12 months. Serum antibody levels to each vaccine component were measured at ages 2, 6, 7, 12 and 13 months. Systemic and local reactions were assessed during the first 3 days after each injection by diary cards distributed to the parents. After the third dose and booster administered at 12 months of age, significant equivalence between the groups was observed, and the geometric mean titer of anti H. influenzae type b capsular polysaccharide (Hib-CP) antibodies were 5.9 and 32.6 micrograms ml-1 for the liquid combination group and 5.8 and 19.4 for the lyophilized group, respectively. After the third dose, anti-Hib-PC antibody levels of > or = 1.0 microgram ml-1 and 0.15 microgram ml-1 were seen in 94% and 100%, respectively, of the liquid combination group and 90 and 99%, respectively of the lyophilized group. After the booster dose, levels of > or = 1.0 microgram ml-1 were observed in 100% and 93.5% of the liquid combination group and the lyophilized combination group, respectively. Systemic and local reactions to the vaccination were generally mild and did not differ significantly between the groups. We conclude that the liquid combination of DTP-PRP-T is safe and at least as immunogenic as the lyophilized preparation. This liquid preparation, like other combined vaccines may be helpful for planning vaccination programs with a reduced number of injections.

Shigella Bacteremia: A Retrospective Study

The aims of this study were to determine the risk factors in, and the clinical and laboratory characterizations of, Shigella bacteremia, as well as the subspecies of Shigella, and the antibiotic susceptibility. A retrospective study of all patients younger than 18 years of age with documented Shigella bacteremia from January 1989 through December 2001 was conducted. Fifteen children with Shigella bacteremia were treated at our center. The mean age (± SD) was 20.5 months (± 34.2), median 7 months. Thirteen (87%) patients failed to gain weight. The mean duration of diarrhea was 14.7 days. Patients were hospitalized for a mean (± SD) of 13.5 days (±9.2). There were no fatalities in our study sample. The vast majority (86.7%) of the Shigella isolates were flexneri. Most isolates were susceptible to ceftriaxone, ciprofloxacine, and gentamicin but resistant to ampicillin and trimethoprim/sulfamethoxazole.

Risk factors for early sepsis in very low birth weight neonates with respiratory distress syndrome

Aim: To identify maternal and neonatal factors that increase suspicion of early sepsis in Very Low Birth Weight neonates with respiratory distress syndrome.

A prospective study of the patterns and dynamics of colonization with Candida spp. in very low birth weight neonates

Abstract Background: Knowledge of fungal colonization patterns in very low birth weight infants (VLBWI) admitted to the neonatal intensive care unit (NICU) is essential in understanding the process of fungal infections in neonates. We analyzed prospectively, during 2009–2010, the patterns and dynamics of fungal colonization in VLBWI, including timing, colonization sites, and species involved. Methods: Weekly skin, oropharynx, and rectum/stool surveillance fungal cultures were collected from admission until discharge in VLBWI in the NICU. None received antifungal prophylaxis. Results: Overall, 118 VLBWI provided 1723 samples; 34 (29%) had 104 positive samples at least once during the first 10 hospitalization weeks. Thirty-nine (33%) weighed < 1000 g; 68 were delivered by cesarean section. Candida albicans (57/104, 55%) and Candida parapsilosis (26/104, 25%) were the main fungi isolated. Eight (24%) VLBWI were colonized during the first week and 23 (68%) during the second week. No differences in colonization were recorded between cesarean section and vaginally delivered VLBWI. The colonization risk at least once during the first 10 weeks was 23% for skin, 14% for oropharynx, 27% for rectum/stool, and 38% for any anatomic site sampled. Persistent colonization was recorded in 5/34 (15%), while transient colonization was found in 14/34 (41%) VLBWI; 16/34 (47%) were discharged or died colonized with Candida spp. Candidemia was diagnosed in 4 (3%) VLBWI and previous/simultaneous colonization was found in 3/4. Conclusions: The cumulative risk of colonization, at any sampled site and at least once during follow-up, was high. Initial colonization occurred most often during the first 2 weeks of life. Colonization dynamics were characterized by various persistence, disappearance, and recolonization patterns. Candidemia was rare.

Neonatal nosocomial pneumococcal infections acquired by patient-to-patient transmission.

A case of neonatal nosocomial pneumococcal sepsis acquired by patient-to-patient transmission and confirmed by phenotypic and genotypic typing is documented. To the best of our knowledge this is the first documented case of neonatal nosocomial person-to-person transmission.

Mother to Child Transmission of Extended Spectrum Beta-Lactamase Producing Enterobacteriaceae

BACKGROUND Preterm infants are at high risk for extended-spectrum-beta-lactamase-producing Enterobacteriaceae (ESBL-E) sepsis and neonatal intensive care unit (NICU) outbreaks. Maternal colonization with ESBL-E may be precursory to mother-to-child transmission. However, there is no consensus regarding surveillance of pregnant women for ESBL-E colonization. AIM To identify pairs of mothers and infants harbouring same-strain ESBL-E colonization and to determine whether maternal transmission may play a role in increasing ESBL-E carriage in preterm infants. METHODS This was a one-year analysis from an ongoing, prospective ESBL-E surveillance of mothers of premature infants and their offspring. Mother-infant pairs colonized with the same bacteria underwent strain analysis using pulsed-field gel electrophoresis (PFGE). Clinical parameters were collected from the hospital computerized records. FINDINGS Between January 2015 and January 2016, 313/409 (76.5%) mothers and all 478 (100%) infants were screened for ESBL-E colonization; carriage rates were 21.5% and 14.8%, respectively. Four (5.6%) colonized infants developed late-onset sepsis and two (2.8%) died. Twenty-five mother-infant pairs colonized with the same bacterial strain were identified; a subgroup of 10 pairs of isolates underwent PFGE, and 70% displayed an identical PFGE fingerprint. No similarities were found between isolates recovered from unrelated neonates and mothers. ESBL-E colonization was found significantly earlier in infants of mothers colonized at birth (P<0.001) compared with infants of non-colonized mothers. CONCLUSIONS ESBL-E carriage rates in mothers and NICU infants with non-negligible maternal-neonatal ESBL-E transmission in the study region indicate that maternal colonization surveillance and/or further infection control interventions should be considered.