Impact of a combined pediatric and adult pneumococcal immunization program on adult pneumonia incidence and mortality in Nicaragua.

BACKGROUND: In 2010, Nicaragua implemented an adult immunization program with the 23-valent pneumococcal polysaccharide vaccine (PPSV-23) and a pediatric immunization program with the 13-valent pneumococcal conjugate vaccine (PCV-13). We assessed incidence rates of ambulatory visits and hospitalizations for pneumonia and pneumonia-related mortality in adults over the age of 50 years before and after the program's implementation in the Department of León, Nicaragua. METHODS: We collected visit diagnoses from all 107 public health facilities between 2008 and 2012 in León. We compared incidence rates of ambulatory visits for pneumonia, pneumonia hospitalizations, and pneumonia-related mortality in the pre-vaccine (2008-2009) and vaccine (2011-2012) periods among older adults using Poisson regression with generalized estimating equations (GEE), controlling for age group, municipality, and proportions of adults who were immunized against influenza. Exposure time was estimated by official municipality population estimates. RESULTS: We did not observe lower incidence rates of ambulatory visits or hospitalizations for pneumonia among adults during the vaccine period versus the pre-vaccine period. However, pneumonia-related mortality was lower in the vaccine period versus the pre-vaccine period, with an adjusted incidence rate ratio (IRRa) of 0.73 (0.56, 0.94) among adults aged 50-64 years, and 0.55 (0.43, 0.70) among adults aged ≥65 years. CONCLUSIONS: These early results following introduction of a combined pediatric and adult pneumococcal immunization program in Nicaragua show a probable impact of the program on the reduction of pneumonia-related deaths in older adults, but a less clear impact on the reduction of health facility visits for pneumonia.

Characterization of enterotoxigenic Escherichia coli strains isolated from Nicaraguan children in hospital, primary care and community settings.

Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrhoea among young children in developing countries. ETEC vaccines offer promise in reducing the burden of ETEC disease, but the development of these vaccines relies on the characterization of ETEC isolates from a variety of settings. To best reflect the full spectrum of ETEC disease in León, Nicaragua, the aim of this study was to characterize ETEC strains isolated from children with diarrhoea attending different settings (hospital, primary care clinics and in the community) and children from different age groups. We characterized ETEC isolates in terms of their colonization factors (CFs) and enterotoxins, and determined whether these factors varied with setting and age group. Diarrhoeal stool samples were obtained from children under the age of 60 months from: (1) the regional public hospital, (2) four public primary care clinics, and (3) a population-based cohort. In total, 58 ETEC-positive isolates were analysed by multiplex-PCR assays for the identification of CFs (CS1, CS2, CS3, CS4, CS5, CS6, CS7, CS8, CS12, CS13, CS14, CS15, CS17, CS18, CS19, CS20, CS21, CS22 and CFA/I), and enterotoxins [heat-labile toxin (LT) and heat-stable variants STh and STp]. The frequency of CFs and enterotoxins was compared among the three settings and for different age groups, using Fisher's exact test or a χ(2) test. At least one CF was detected among one-half of samples; CS19 was detected among all strains in which a CF was identified, either alone or in combination with another CF. Among all CFs detected, 91.7 % were identified as members of the class 5 fimbrial family. CFs were detected more commonly among samples from infants captured in the health facility setting compared with the community setting. Overall, LT was detected among 67.2 % of samples, STh was detected among 20.7 % and both enterotoxins were detected among 12.1 %. The enterotoxin STh was detected more commonly among cases in the community, whilst a combination of STh and LT was detected more commonly among cases treated in health facilities. Our results suggest that, to protect against diarrhoeal cases associated with this E. coli pathotype in León, Nicaragua, an ETEC vaccine that effectively targets the archeotype CFA/I of the class 5 fimbrial family would be the most effective in this setting.

Changes in childhood pneumonia and infant mortality rates following introduction of the 13-valent pneumococcal conjugate vaccine in Nicaragua.

BACKGROUND: In 2010, Nicaragua became the first developing nation to add 13-valent pneumococcal conjugate vaccine (PCV-13) to its national immunization schedule, using a "3+0" dosing schedule. We assessed changes in incidence rates of health facility visits for childhood pneumonia and infant mortality after PCV-13 introduction in the Department of León, Nicaragua. METHODS: We collected visit diagnoses from all 107 public health facilities in León between 2008 and 2012. We compared rates of pneumonia hospitalizations, ambulatory visits for pneumonia and infant mortality during the prevaccine (2008-2010) and vaccine (2011-2012) periods among different age groups of children using generalized estimating equations, accounting for clustering by municipality. Exposure time was estimated by official municipality population estimates. RESULTS: The adjusted incidence rate ratio for pneumonia hospitalization in the vaccine versus prevaccine period was 0.67 (0.59-0.75) among infants and 0.74 (0.67-0.81) among 1-year olds. The adjusted incidence rate ratio for ambulatory visits for pneumonia was 0.87 (0.75-1.01) among infants, and 0.84 (0.74, 0.95) among 1-year olds. The adjusted incidence rate ratio for infant mortality was 0.67 (0.57-0.80). We also observed lower rates of health facility visits for pneumonia among age groups (2- to 4-year old and 5- to 14-year old) not eligible to receive PCV-13. CONCLUSIONS: Within the first 2 years of a PCV-13 immunization program in Nicaragua, we observed lower rates of hospitalizations and ambulatory visits for pneumonia among children of all ages and a lower infant mortality rate. Lower rates of pneumonia among age groups not eligible to receive PCV-13 suggest an indirect effect of the vaccine.

Antibiotic resistance patterns of intestinal Escherichia coli isolates from Nicaraguan children.

In developing countries, diarrhoeal diseases are one of the major causes of death in children under 5 years of age. It is known that diarrhoeagenic Escherichia coli (DEC) is an important aetiological agent of infantile diarrhoea in Nicaragua. However, there are no recent studies on antimicrobial resistance among intestinal E. coli isolates in Nicaraguan children. The aim of the present study was to determine the antimicrobial resistance pattern in a collection of 727 intestinal E. coli isolates from the faeces of children in León, Nicaragua, between March 2005 and September 2006. All samples had been screened previously for the presence of DEC by multiplex PCR. Three hundred and ninety-five non-DEC isolates (270 from children with diarrhoea and 125 from children without diarrhoea) and 332 DEC isolates (241 from children with diarrhoea and 91 from children without diarrhoea) were analysed in this study. In general, antimicrobial resistance among the 727 intestinal E. coli isolates was high for ampicillin (60 %), trimethoprim-sulfamethoxazole (64 %) and chloramphenicol (11 %). Among individual E. coli categories, enteroaggregative E. coli isolates from children with and without diarrhoea exhibited significantly higher levels of resistance (P<0.05) to ampicillin and trimethoprim-sulfamethoxazole compared to the other E. coli categories. Resistance to ceftazidime and/or ceftriaxone and a pattern of multi-resistance was related to CTX-M-5- or CTX-M-15-producing E. coli isolates. The results suggest that E. coli isolates from Nicaraguan children have not reached the high levels of resistance to the most common antibiotics used for diarrhoea treatment as in other countries.