Immune Response Persistence and Safety of a Booster Dose of the Tetravalent Dengue Vaccine in Adolescents and Adults Who Previously Completed the 3-dose Schedule 4-5 Years Earlier in Latin America: A Randomized Placebo-controlled Trial.

BACKGROUND: We previously described an increased immune response 28 days after a booster dose of the live, attenuated, tetravalent dengue vaccine (CYD-TDV) in healthy adolescents and adults in Latin America (CYD64, NCT02623725). This follow-up study evaluated immune response persistence and safety of a CYD-TDV booster dose up to Month (M) 24 post-booster. METHODS: This study included 250 participants who previously received 3 primary doses of CYD-TDV in the CYD13 (NCT00993447) and CYD30 (NCT01187433) studies, and who were randomized 4-5 years later to receive a CYD-TDV booster or placebo (3:1). Dengue neutralizing antibodies against the parental dengue virus strains were assessed using the plaque reduction neutralization test (PRNT50) at M6, M12, and M24 post-booster. Post-booster memory B-cell responses were assessed in a subset of participants using the FluoroSpot assay up to M12 post-booster. RESULTS: In the CYD-TDV group (n = 187), dengue neutralizing antibody geometric mean titers (GMTs) declined from the peak at day 28 through to M24 for all serotypes. GMTs at M24 were similar to those at pre-booster among baseline dengue seropositives. A similar trend was observed for baseline dengue seronegatives, albeit at a lower magnitude. Previous vaccination-induced detectable B-cell memory responses in seropositives and seronegatives that decreased to pre-booster levels at M12 post-booster. The CYD-TDV booster dose was well-tolerated. CONCLUSIONS: In baseline dengue seropositives, following a CYD-TDV booster dose administered 4-5 years after primary immunization, dengue neutralizing antibody GMTs and B-cell memory responses peaked in the short-term before gradually decreasing over time. A CYD-TDV booster dose could improve protection against dengue during outbreak periods.

Effectiveness of an educational strategy to increase plain water consumption in children / Efectividad de una estrategia educativa para incrementar el consumo de agua simple en niños

Abstract: Objective: We tested the effectiveness of the I prefer plain water educational strategy used to increase water consumption in elementary school children. Materials and methods: A community intervention trial was performed in eight public elementary schools in Mexico City. The schools were randomized into an intervention (IG) and a control (CG) group. Each school was provided water dispensers inside the classrooms. The IG received the educational strategy. The strategy was considered effective if the students increased their water consumption by ≥220 ml. Results: Water consumption in the IG increased 167 ml vs. 37 ml in CG (p < 0.001). The goal of the educational strategy for water consumption was achieved in 166/413 children in the IG and 95/364 children in the CG (p < 0.001). Conclusions: I prefer plain water, associated with free access to water inside the classrooms, proved to be effective to increase water consumption.

Resumen: Objetivo: Evaluar la efectividad de la estrategia Prefiero agua simple para incrementar el consumo de agua en niños de escuelas primarias públicas. Material y métodos: Ensayo de intervención comunitaria en ocho escuelas en la Ciudad de México. Las escuelas se aleatorizaron en grupo de intervención (GI) y de control (GC). Se instalaron dispensadores de agua dentro de las aulas. Implementamos la estrategia al GI. Consideramos efectiva la estrategia si los estudiantes incrementaron su consumo de agua en ≥220 ml. Resultados: El incremento global en el consumo de agua del GI fue de 167 ml vs. 37 ml en GC (p <0.001). La efectividad de la estrategia para el consumo de agua se logró en 166/413 niños del GI y en 95/364 niños del GC (p <0.001). Conclusiones: Prefiero agua simple, asociada con libre acceso al agua dentro de las aulas, demostró ser efectiva para incrementar el consumo de agua.

Effectiveness of an educational strategy to increase plain water consumption in children.

OBJECTIVE: We tested the effectiveness of the I prefer plain water educational strategy used to increase water consumption in elementary school children. MATERIALS AND METHODS: A community intervention trial was performed in eight public elementary schools in Mexico City. The schools were randomized into an intervention (IG) and a control (CG) group. Each school was provided water dispensers inside the classrooms. The IG received the educational strategy. The strategy was considered effective if the students increased their water consumption by ≥220 ml. RESULTS: Water consumption in the IG increased 167 ml vs. 37 ml in CG (p < 0.001). The goal of the educational strategy for water consumption was achieved in 166/413 children in the IG and 95/364 children in the CG (p < 0.001). CONCLUSIONS: I prefer plain water, associated with free access to water inside the classrooms, proved to be effective to increase water consumption.

OBJECTIVE: Evaluar la efectividad de la estrategia Prefiero agua simple para incrementar el consumo de agua en niños de escuelas primarias públicas. MATERIALS AND METHODS: Ensayo de intervención comunitaria en ocho escuelas en la Ciudad de México. Las escuelas se aleatorizaron en grupo de intervención (GI) y de control (GC). Se instalaron dispensadores de agua dentro de las aulas. Implementamos la estrategia al GI. Consideramos efectiva la estrategia si los estudiantes incrementaron su consumo de agua en ≥220 ml. RESULTS: El incremento global en el consumo de agua del GI fue de 167 ml vs. 37 ml en GC (p < 0.001). La efectividad de la estrategia para el consumo de agua se logró en 166/413 niños del GI y en 95/364 niños del GC (p < 0.001). CONCLUSIONS: Prefiero agua simple, asociada con libre acceso al agua dentro de las aulas, demostró ser efectiva para incrementar el consumo de agua.

Dengue Vaccine Booster in Healthy Adolescents and Adults in Latin America: Evaluation 4-5 Years After a Primary 3-Dose Schedule.

BACKGROUND: The tetravalent dengue vaccine (CYD-TDV, Dengvaxia, Sanofi Pasteur) demonstrated efficacy in 2 previous phase III trials conducted in endemic countries. Neutralizing antibodies (NAbs) elicited by 3 doses of this vaccine have been associated with efficacy. Long-term follow-up data has shown that NAb immune responses tend to wane over time, after the third dose. This study compared the immune response elicited by a booster (4th) dose of CYD-TDV with the immune responses from the same participants obtained post-dose 3 of the primary series administered 4-5 years earlier. METHODS: This multicenter, observer-blind, randomized, placebo-controlled, phase II noninferiority trial was conducted in healthy adolescents and adults in dengue endemic countries of Latin America (Colombia, Honduras, Brazil, Mexico and Puerto Rico). All participants had been immunized with 3 doses of CYD-TDV in phase II studies conducted 4-5 years earlier. NAb levels against each dengue virus serotype 28 days postbooster or placebo injection were reported. RESULTS: A total of 187 participants received CYD-TDV and 64 received placebo. Prospectively defined noninferiority criteria for dengue NAbs after the booster dose compared with postdose 3 were met for all 4 serotypes. Prospectively defined superiority criteria were met for 3 of the 4 serotypes. CONCLUSIONS: Antidengue NAb levels can be boosted to levels at least as high as, or higher than those observed after completion of the primary 3-dose series, with an additional dose of CYD-TDV 4-5 years after the standard 3-dose vaccination schedule.

Neurological complications and death in children with dengue virus infection: report of two cases.

BACKGROUND: Dengue virus infection can have different complications; the best known is hemorrhagic dengue fever. However, other effects such as neurological disorders may endanger the lives of patients. Dengue neurological manifestations can be confused with encephalitis symptoms and can lead to cerebral edema and death. Therefore, we consider important in the endemic areas to take into account the diagnosis of dengue encephalitis in patients with neurological disorders, and to request the determination of serology in cerebrospinal fluid for the NS1 antigen test. CASE PRESENTATION: We present the cases of two patients from the state of Morelos, Mexico, with 17 and 14 years of age. Both cases presented a rapid evolution characterized by fever, seizures and neurological deterioration secondary to severe cerebral edema that evolved to cerebral death in both cases. The diagnosis of brain death was confirmed by electroencephalogram in both patients. The two patients were submitted to serology for NS1 that tested positive in both cases. They died between the second and fifth day after admission. CONCLUSIONS: Retrospective studies have found that up to 4% of the patients have dengue virus infections, which leads us to believe that in endemic areas, this infection should be suspected in cases of encephalic and febrile symptoms. RT-PCR should be performed to identify cases of encephalitis caused by the dengue virus, and early interventions should be performed to attempt to reduce the morbidity and mortality of these cases.

Effectiveness of senna vs polyethylene glycol as laxative therapy in children with constipation related to anorectal malformation.

PURPOSE: Constipation is present in 80% of children with corrected anorectal malformations, usually associated to rectal dilation and hypomotility. Osmotic laxatives are routinely used for idiopathic constipation. Senna is a stimulant laxative that produces contractions improving colonic motility without affecting the stool consistency. We designed this trial to study the effectiveness of Senna versus polyethylene glycol for the treatment of constipation in children with anorectal malformation. METHODS: A randomized controlled crossover design clinical trial, including a washout period, was conducted, including children with corrected anorectal malformations with fecal continence and constipation. The sample size was calculated for proportions (n=28) according to available data for Senna. Effectiveness of laxative therapy was measured with a three variable construct: 1) daily bowel movement, 2) fecal soiling, 3) a "clean" abdominal x-ray. Data analysis included descriptive statistics and a Fisher's exact test for the outcome variable (effectiveness). RESULTS: The study was terminated early because the interim analysis showed a clear benefit toward Senna (p = 0.026). The sample showed a normal statistical distribution for the variables age and presence of megarectum. The maximum daily dose of Senna (sennosides A and B) was 38.7mg and 17g for polyethylene glycol. No adverse effects were identified. CONCLUSION: Therapy with Senna should be the laxative treatment of choice as part of a bowel management program in children with repaired anorectal malformations and constipation, since the stimulation of colonic propulsion waves could lead to stool evacuation without modification of its consistency which can affect fecal continence. LEVEL OF EVIDENCE: I - randomized controlled trial with adequate statistical power.

Neurological complications and death in children with dengue virus infection: report of two cases

Abstract Background Dengue virus infection can have different complications; the best known is hemorrhagic dengue fever. However, other effects such as neurological disorders may endanger the lives of patients. Dengue neurological manifestations can be confused with encephalitis symptoms and can lead to cerebral edema and death. Therefore, we consider important in the endemic areas to take into account the diagnosis of dengue encephalitis in patients with neurological disorders, and to request the determination of serology in cerebrospinal fluid for the NS1 antigen test. Case presentation We present the cases of two patients from the state of Morelos, Mexico, with 17 and 14 years of age. Both cases presented a rapid evolution characterized by fever, seizures and neurological deterioration secondary to severe cerebral edema that evolved to cerebral death in both cases. The diagnosis of brain death was confirmed by electroencephalogram in both patients. The two patients were submitted to serology for NS1 that tested positive in both cases. They died between the second and fifth day after admission. Conclusions Retrospective studies have found that up to 4% of the patients have dengue virus infections, which leads us to believe that in endemic areas, this infection should be suspected in cases of encephalic and febrile symptoms. RT-PCR should be performed to identify cases of encephalitis caused by the dengue virus, and early interventions should be performed to attempt to reduce the morbidity and mortality of these cases.

Neurological complications and death in children with dengue virus infection: report of two cases

Background Dengue virus infection can have different complications; the best known is hemorrhagic dengue fever. However, other effects such as neurological disorders may endanger the lives of patients. Dengue neurological manifestations can be confused with encephalitis symptoms and can lead to cerebral edema and death. Therefore, we consider important in the endemic areas to take into account the diagnosis of dengue encephalitis in patients with neurological disorders, and to request the determination of serology in cerebrospinal fluid for the NS1 antigen test. Case presentation We present the cases of two patients from the state of Morelos, Mexico, with 17 and 14 years of age. Both cases presented a rapid evolution characterized by fever, seizures and neurological deterioration secondary to severe cerebral edema that evolved to cerebral death in both cases. The diagnosis of brain death was confirmed by electroencephalogram in both patients. The two patients were submitted to serology for NS1 that tested positive in both cases. They died between the second and fifth day after admission. Conclusions Retrospective studies have found that up to 4% of the patients have dengue virus infections, which leads us to believe that in endemic areas, this infection should be suspected in cases of encephalic and febrile symptoms. RT-PCR should be performed to identify cases of encephalitis caused by the dengue virus, and early interventions should be performed to attempt to reduce the morbidity and mortality of these cases.(AU)

Efficacy and Long-Term Safety of a Dengue Vaccine in Regions of Endemic Disease.

BACKGROUND: A candidate tetravalent dengue vaccine is being assessed in three clinical trials involving more than 35,000 children between the ages of 2 and 16 years in Asian-Pacific and Latin American countries. We report the results of long-term follow-up interim analyses and integrated efficacy analyses. METHODS: We are assessing the incidence of hospitalization for virologically confirmed dengue as a surrogate safety end point during follow-up in years 3 to 6 of two phase 3 trials, CYD14 and CYD15, and a phase 2b trial, CYD23/57. We estimated vaccine efficacy using pooled data from the first 25 months of CYD14 and CYD15. RESULTS: Follow-up data were available for 10,165 of 10,275 participants (99%) in CYD14 and 19,898 of 20,869 participants (95%) in CYD15. Data were available for 3203 of the 4002 participants (80%) in the CYD23 trial included in CYD57. During year 3 in the CYD14, CYD15, and CYD57 trials combined, hospitalization for virologically confirmed dengue occurred in 65 of 22,177 participants in the vaccine group and 39 of 11,089 participants in the control group. Pooled relative risks of hospitalization for dengue were 0.84 (95% confidence interval [CI], 0.56 to 1.24) among all participants, 1.58 (95% CI, 0.83 to 3.02) among those under the age of 9 years, and 0.50 (95% CI, 0.29 to 0.86) among those 9 years of age or older. During year 3, hospitalization for severe dengue, as defined by the independent data monitoring committee criteria, occurred in 18 of 22,177 participants in the vaccine group and 6 of 11,089 participants in the control group. Pooled rates of efficacy for symptomatic dengue during the first 25 months were 60.3% (95% CI, 55.7 to 64.5) for all participants, 65.6% (95% CI, 60.7 to 69.9) for those 9 years of age or older, and 44.6% (95% CI, 31.6 to 55.0) for those younger than 9 years of age. CONCLUSIONS: Although the unexplained higher incidence of hospitalization for dengue in year 3 among children younger than 9 years of age needs to be carefully monitored during long-term follow-up, the risk among children 2 to 16 years of age was lower in the vaccine group than in the control group. (Funded by Sanofi Pasteur; ClinicalTrials.gov numbers, NCT00842530, NCT01983553, NCT01373281, and NCT01374516.).

Efficacy of a tetravalent dengue vaccine in children in Latin America.

BACKGROUND: In light of the increasing rate of dengue infections throughout the world despite vector-control measures, several dengue vaccine candidates are in development. METHODS: In a phase 3 efficacy trial of a tetravalent dengue vaccine in five Latin American countries where dengue is endemic, we randomly assigned healthy children between the ages of 9 and 16 years in a 2:1 ratio to receive three injections of recombinant, live, attenuated, tetravalent dengue vaccine (CYD-TDV) or placebo at months 0, 6, and 12 under blinded conditions. The children were then followed for 25 months. The primary outcome was vaccine efficacy against symptomatic, virologically confirmed dengue (VCD), regardless of disease severity or serotype, occurring more than 28 days after the third injection. RESULTS: A total of 20,869 healthy children received either vaccine or placebo. At baseline, 79.4% of an immunogenicity subgroup of 1944 children had seropositive status for one or more dengue serotypes. In the per-protocol population, there were 176 VCD cases (with 11,793 person-years at risk) in the vaccine group and 221 VCD cases (with 5809 person-years at risk) in the control group, for a vaccine efficacy of 60.8% (95% confidence interval [CI], 52.0 to 68.0). In the intention-to-treat population (those who received at least one injection), vaccine efficacy was 64.7% (95% CI, 58.7 to 69.8). Serotype-specific vaccine efficacy was 50.3% for serotype 1, 42.3% for serotype 2, 74.0% for serotype 3, and 77.7% for serotype 4. Among the severe VCD cases, 1 of 12 was in the vaccine group, for an intention-to-treat vaccine efficacy of 95.5%. Vaccine efficacy against hospitalization for dengue was 80.3%. The safety profile for the CYD-TDV vaccine was similar to that for placebo, with no marked difference in rates of adverse events. CONCLUSIONS: The CYD-TDV dengue vaccine was efficacious against VCD and severe VCD and led to fewer hospitalizations for VCD in five Latin American countries where dengue is endemic. (Funded by Sanofi Pasteur; ClinicalTrials.gov number, NCT01374516.).

[Guía latinoamericana para el diagnóstico y tratamiento de alergia a las proteínas de la leche de vaca (GL-APLV)].

Cow's milk allergy (CMA) is an immune-based disease that has become an increasing problem. The diagnosis and management of CMA varies from one clinical setting to another and represents a challenge in pediatric practice. In addition, because nonallergic food reactions can be confused with CMA symptoms, there is an overdiagnosis of the disease. In response to these situations, pediatric specialties from recognized institutions throughout Latin America decided to develop a clinical guideline for diagnosis and management of cow's milk allergy. These guidelines include definitions, epidemiology, pathophysiology overview, clinical and evidencebased recommendations for the diagnosis and treatment of CMA. They also include prevention and prognosis sections and identify gaps in the current knowledge to be addressed through future research.

Safety and immunogenicity of a recombinant tetravalent dengue vaccine in 9-16 year olds: a randomized, controlled, phase II trial in Latin America.

BACKGROUND: The dengue virus is a member of the Flavivirus (FV) genus, which also includes the yellow fever virus. Dengue disease is caused by any 1 of 4 dengue virus serotypes and is a serious public health concern in Latin America. This study evaluated the safety and immunogenicity of a candidate recombinant, live-attenuated, tetravalent dengue vaccine (CYD-TDV) in 9-16 year olds in Latin America. METHODS: In this randomized, blinded, controlled study, volunteers received either 3 doses of CYD-TDV (n = 401) or placebo as first and second injection and tetanus/diphtheria/acellular pertussis vaccine as third injection (n = 199) at 0, 6 and 12 months. Adverse events were documented. Plaque reduction neutralization test antibody titers against the 4 CYD-TDV parental strains were measured before and 28 days after each dose. Seropositivity was defined as antibody titers ≥10 1/dil. RESULTS: The number of adverse reactions decreased after each successive CYD-TDV dose. After each CYD-TDV dose, antibody titers against all 4 serotypes were higher than baseline and respective predose titers. After the third dose of CYD-TDV, 100%, 98.6% and 93.4% of participants were seropositive for at least 2, at least 3 or all 4 serotypes, respectively. Higher antibody titers were observed in participants in the CYD-TDV group who were FV-seropositive at baseline compared with those who were FV-seronegative. CONCLUSIONS: CYD-TDV had a favorable safety profile and elicited antibody responses against all 4 dengue virus serotypes in 9-16 year olds in Latin America. These findings support the continued development of CYD-TDV.

Nitrofurantoin, phenazopyridine, and the superoxide-response regulon soxRS of Escherichia coli.

Nitrofurantoin and phenazopyridine are two drugs commonly used against urinary tract infections. Both compounds exert oxidative damage in patients deficient in glucose-6-phosphate dehydrogenase. This study was done to assess the interactions of these drugs with the soxRS regulon of Escherichia coli, a superoxide-defense system (that includes a nitroreductase that yields the active metabolite of nitrofurantoin) involved in antibiotic multi-resistance. The effects of either nitrofurantoin or phenazopyridine, upon strains with different soxRS genotypes, were measured as minimum inhibitory concentrations (MICs) and growth curves. Also, the ability of these drugs to induce the expression of a soxS'::lacZ gene fusion was assessed. The effect of antibiotics in the presence of phenazopyridine, paraquat (a known soxRS inducer), or an efflux inhibitor, was measured using the disk diffusion method. A strain constitutively expressing the soxRS regulon was slightly more susceptible to nitrofurantoin, and more resistant to phenazopyridine, compared to wild-type and soxRS-deleted strains, during early treatment, but 24-h MICs were the same (8 mg/l nitrofurantoin, 1,000 mg/l phenazopyridine) for all strains. Both compounds were capable of inducing the expression of a soxS'::lacZ fusion, but less than paraquat. Subinhibitory concentrations of phenazopyridine increased the antimicrobial effect of ampicillin, chloramphenicol, tetracycline, and nitrofurantoin. The induction or constitutive expression of the soxRS regulon seems to be a disadvantage for E. coli during nitrofurantoin exposure; but might be an advantage during phenazopyridine exposure, indicating that the latter compound could act as a selective pressure for mutations related to virulence and antibiotic multi-resistance.

Interleukin-1 receptor antagonist gene polymorphism increases susceptibility to septic shock in children with acute lymphoblastic leukemia.

BACKGROUND: Interleukin-1 receptor antagonist polymorphism (ILRN) 2 (ILRN*2) has been associated with a poor outcome in septic patients because of an elevated production of anti-inflammatory cytokines. In >70% of patients, morbidity and mortality in childhood acute lymphoblastic leukemia is caused by infections. The aim of this study was to determine the association between this polymorphism and the frequency of septic shock from the time of diagnosis until completion of treatment. METHODS: This cohort study was conducted in 57 consecutive children with acute lymphoblastic leukemia. At the end of follow-up, children were stratified according to their IL1RN polymorphism (ILRN*1/ILRN*2), evaluating the impact of genotype on the severity of febrile neutropenic events during their treatment. RESULTS: Overall survival was 80% at 55 months after treatment. The average number of febrile neutropenic events in this cohort was 2.82 per patient. Genotype distribution was 50.9% for homozygote IL-1RN*1, 38.6% for heterozygote ILRN*1/ILRN*2 and 10.5% for homozygote IL-1RN*2. The risk of presenting septic shock for homozygote IL1RN*2/IL1RN*2 and heterozygote ILRN*1/ILRN*2 patients was significantly greater (odds ratio, 45; P = 0.001) adjusted for age, gender, risk of leukemia and presence of pathogenic bacteria. Genotype IL-1RN*2 is associated with the risk of development of septic shock in children with acute lymphoblastic leukemia. Further research in larger population-based studies is needed to replicate these findings. CONCLUSIONS: This information would allow us to identify more predictive factors in this group of acute lymphoblastic leukemia patients in whom this information is lacking to establish an earlier and more aggressive approach.

Serotypes and antibiotic susceptibility of Streptococcus pneumoniae isolates causative of invasive diseases in Mexican children.

INTRODUCTION: Streptococcus pneumoniae is a worldwide leading cause of morbidity and mortality, while susceptibility towards penicillin and macrolides can be less than 50% in many regions. METHODOLOGY: A total of 150 isolates of S. pneumoniae causative of invasive diseases in children were characterized, of which 24.6% had a fatal outcome. RESULTS: The most prevalent serotypes were 19F, 6B, 23F and 14. Resistance to penicillin, erythromycin (mostly of macrolide-lincosamide-streptogramin resistance phenotype) or trimethoprim-sulfamethoxazole was found in more than 40% of the isolates, but no resistance phenotype appeared linked to lethality. Serotype 3 isolates, which were seldom resistant, had a twofold lethality rate compared to the total sample. CONCLUSION: Serotyping could provide a better outcome-predicting tool than susceptibility testing. The seven-valent vaccine does not include the most prevalent serotypes found in Mexico.

Mycobacterium tuberculosis Complex Genotype Diversity and Drug Resistance Profiles in a Pediatric Population in Mexico.

The aim of this study was to determine the frequency of drug resistance and the clonality of genotype patterns in M. tuberculosis clinical isolates from pediatric patients in Mexico (n = 90 patients from 19 states; time period-January 2002 to December 2003). Pulmonary disease was the most frequent clinical manifestation (71%). Children with systemic tuberculosis (TB) were significantly younger compared to patients with localized TB infections (mean 7.7 ± 6.2 years versus 15 ± 3.4 years P = 0.001). Resistance to any anti-TB drug was detected in 24/90 (26.7%) of the isolates; 21/90 (23.3%) and 10/90 (11.1%) were resistant to Isoniazid and Rifampicin, respectively, and 10/90 (11.1%) strains were multidrug-resistant (MDR). Spoligotyping produced a total of 55 different patterns; 12/55 corresponded to clustered isolates (n = 47, clustering rate of 52.2%), and 43/55 to unclustered isolates (19 patterns were designated as orphan by the SITVIT2 database). Database comparison led to designation of 36 shared types (SITs); 32 SITs (n = 65 isolates) matched a preexisting shared type in SITVIT2, whereas 4 SITs (n = 6 isolates) were newly created. Lineage classification based on principal genetic groups (PGG) revealed that 10% of the strains belonged to PGG1 (Bovis and Manu lineages). Among PGG2/3 group, the most predominant clade was the Latin-American and Mediterranean (LAM) in 27.8% of isolates, followed by Haarlem and T lineages. The number of single drug-resistant (DR) and multidrug-resistant (MDR-TB) isolates in this study was similar to previously reported in studies from adult population with risk factors. No association between the spoligotype, age, region, or resistance pattern was observed. However, contrary to a study on M. tuberculosis spoligotyping in Acapulco city that characterized a single cluster of SIT19 corresponding to the EAI2-Manila lineage in 70 (26%) of patients, not a single SIT19 isolate was found in our pediatric patient population. Neither did we find any shared type belonging to the EAI family which represents ancestral PGG1 strains within the M. tuberculosis complex. We conclude that the population structure of pediatric TB in our setting is different from the one prevailing in adult TB patient population of Guerrero.