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Borrelia burgdorferi sensu lato infection has been confirmed in clinical cases in the northeast of Mexico; however, the bacterium has not been identified as infecting the tick vector Ixodes, Amblyomma and Dermacentor ticks were collected from mammals and plants in northeastern Mexico and examined for Borrelia. Eighteen of 214 ticks were PCR-positive for the fla and 16S rRNA genes and 15 for the ospA gene. Southern blotting with a fla probe and sequencing of ospA genes confirmed infection with B. burgdorferi sensu stricto. These findings, together with reports of indigenous cases, fulfil the criteria that allow northeastern Mexico to be considered as a zone endemic for Lyme disease. [ABSTRACT FROM AUTHOR]

Background: Spotted fever rickettsiosis is a serious disease with a high mortality rate if not timely detected., Objective: To describe the characteristics of patients hospitalized for spotted fever rickettsiosis, as well as the risk factors associated with poor prognosis., Material and Methods: Data from medical records of patients hospitalized between August 2012 and July 2022 were collected. Variables were analyzed using Mann-Whitney's U-test, Fisher's exact test, and univariate or multivariate logistic regression analysis., Results: Twenty-six patients were analyzed, among which a mortality of 57.6% was identified. In the between-group comparison, platelet count was lower in non-survivors (16.0 × 10 3 /μL vs. 25.9 × 10 3 /μL, p = 0.031). The percentage of surviving patients who received treatment more than 72 hours after fever onset was 45.5% (five patients) vs. 86.7% of non-survivors (13 patients) (p = 0.034). Receiving treatment 72 hours after fever onset increased by 7.09 times the probability of a fatal outcome (OR = 8.09, 95% CI = 1.1-55.8, p = 0.034)., Conclusions: Starting adequate treatment 72 hours after the onset of fever may be an important risk factor for mortality, hence the importance of timely diagnosis and appropriate treatment of this disease., (Copyright: © 2023 Permanyer.)

Background: The new coronavirus SARS-CoV-2 pandemic has been relatively less lethal in children; however, poor prognosis and mortality has been associated with factors such as access to health services. Mexico remained on the list of the ten countries with the highest case fatality rate (CFR) in adults. It is of interest to know the behavior of COVID-19 in the pediatric population. The aim of this study was to identify clinical and sociodemographic variables associated with mortality due to COVID-19 in pediatric patients., Objective: Using National open data and information from the Ministry of Health, Mexico, this cohort study aimed to identify clinical and sociodemographic variables associated with COVID-19 mortality in pediatric patients., Method: A cohort study was designed based on National open data from the Ministry of Health, Mexico, for the period April 2020 to January 2022, and included patients under 18 years of age with confirmed SARS-CoV-2 infection. Variables analyzed were age, health services used, and comorbidities (obesity, diabetes, asthma, cardiovascular disease, immunosuppression, high blood pressure, and chronic kidney disease). Follow-up duration was 60 days, and primary outcomes were death, hospitalization, and requirement of intensive care. Statistical analysis included survival analysis, prediction models created using the Cox proportional hazards model, and Kaplan-Meier estimation curves., Results: The cohort included 261,099 cases with a mean age of 11.2 ± 4 years, and of these, 11,569 (4.43%) were hospitalized and 1,028 (0.39%) died. Variables associated with risk of mortality were age under 12 months, the presence of comorbidities, health sector where they were treated, and first wave of infection., Conclusion: Based on data in the National database, we show that the pediatric fatality rate due to SARS-CoV-2 is similar to that seen in other countries. Access to health services and distribution of mortality were heterogeneous. Vulnerable groups were patients younger than 12 months and those with comorbidities., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Solórzano-Santos, Miranda-Lora, Márquez-González and Klünder-Klünder.)

Introduction: Group B Streptococcus (GBS) causes infections in women during pregnancy and puerperium and invasive infections in newborns. The genes lmb, cylE, scpB, and hvgA are involved with increased virulence of GBS, and hypervirulent clones have been identified in different regions. In addition, increasing resistance of GBS to macrolides and lincosamides has been reported, so knowing the patterns of antibiotic resistance may be necessary to prevent and treat GBS infections. This study aimed to identify virulence genes and antibiotic resistance associated with GBS colonization in pregnant women from northeastern Mexico., Methods: Pregnant women with 35-37 weeks of gestation underwent recto-vaginal swabbing. One swab was inoculated into Todd-Hewitt broth supplemented with gentamicin and nalidixic acid, a second swab was inoculated into LIM enrichment broth, and a third swab was submerged into a transport medium. All samples were subcultured onto blood agar. After overnight incubation, suggestive colonies with or without hemolysis were analyzed to confirm GBS identification by Gram staining, catalase test, hippurate hydrolysis, CAMP test, and incubation in a chromogenic medium. We used latex agglutination to confirm and serotype GBS isolates. Antibiotic resistance patterns were assessed by Vitek 2 and disk diffusion. Periumbilical, rectal and nasopharyngeal swabs were collected from some newborns of colonized mothers. All colonized women and their newborns were followed up for three months to assess the development of disease attributable to GBS. Draft genomes of all GBS isolates were obtained by whole-genome sequencing. In addition, bioinformatic analysis to identify genes encoding capsular polysaccharides and virulence factors was performed using BRIG, while antibiotic resistance genes were identified using the CARD database., Results: We found 17 GBS colonized women out of 1154 pregnant women (1.47%). None of the six newborns sampled were colonized, and no complications due to GBS were detected in pregnant women or newborns. Three isolates were serotype I, 5 serotype II, 3 serotype III, 4 serotype IV, and 2 serotype V. Ten distinct virulence gene profiles were identified, being scpB, lmb, fbsA, acp, PI-1, PI-2a, cylE the most common (3/14, 21%). The virulence genes identified were scpB, lmb, cylE, PI-1, fbsA, PI-2a, acp, fbsB, PI-2b, and hvgA. We identified resistance to tetracycline in 65% (11/17) of the isolates, intermediate susceptibility to clindamycin in 41% (7/17), and reduced susceptibility to ampicillin in 23.5% (4/17). The tetM gene associated to tetracyclines resistance was found in 79% (11/14) and the mel and mefA genes associated to macrolides resistance in 7% (1/14)., Conclusions: The low prevalence of colonization and the non-occurrence of mother-to-child transmission suggest that the intentional search for GBS colonization in this population is not justified. Our results also suggest that risk factors should guide the use of intrapartum antibiotic prophylaxis. The detection of strains with genes coding virulence factors means that clones with pathogenic potential circulates in this region. On the other hand, the identification of decreased susceptibility to antibiotics from different antimicrobial categories shows the importance of adequately knowing the resistance patterns to prevent and to treat GBS perinatal infection., Competing Interests: The authors have declared that no competing interests exist.

Pertussis is a highly contagious disease caused by Bordetella pertussis, which may be preventable by vaccination. There are two types of vaccines: whole-cell vaccines and acellular vaccines. Since pertussis control worldwide is heterogeneous, re-emergence of whooping cough has been observed in some countries. This re-emergence has been related to several factors: increased susceptibility to infection, better detection of disease, problems in obtaining adequate vaccination coverage, increase in susceptible subjects (mainly under 6 months of age), loss of immunity in adolescents and young adults, and likely genetic and adaptive B. pertussis changes. This paper discusses whole-cell and acellular vaccines' characteristics, advantages, and disadvantages. International recommendations are presented, and the participants' position is offered regarding the influence of the use of acellular vaccines and the potential disadvantages of reintroducing whole-cell vaccines, mainly due to their reactogenicity. Finally, strategies to achieve better control of pertussis in Mexico are discussed.

Background: Acute otitis media (AOM) is one of the most prevalent acute conditions in the pediatric population worldwide. This work aimed to elaborate a Clinical Practice Guideline with clinical recommendations systematically developed to assist decision-making of specialists, patients, caregivers, and public policymakers involved in managing patients with AOM in children., Methods: This document was developed by the College of Pediatric Otorhinolaryngology and Head, and Neck Surgery of Mexico (COPEME) in compliance with international standards. The SIGN quality of evidence classification was used. On behalf of the COPEME, the Guideline Development Group (GDG) was integrated, including otolaryngologists, infectologists, pediatricians, general practitioners, and methodologists with experience in systematic literature reviews and the development of clinical practice guidelines., Results: A consensus was reached on 18 clinical questions, covering what was previously established by the GDG in the scope document of the guidelines. Scientific evidence answering each of these clinical questions was identified and critically evaluated. The GDG agreed on the final wording of the clinical recommendations using the modified Delphi panel technique. Specialists and patient representatives conducted an external validation., Conclusions: This Clinical Practice Guideline presents clinical recommendations for the prevention, diagnosis, and management of AOM to assist shared decision-making among physicians, patients, and caregivers and improve the quality of clinical care., (Copyright: © 2022 Permanyer.)

Background: SARS-COV2 appears less frequently and less severely in the pediatric population than in the older age groups. There is a need to precisely estimate the specific risks for each age group to design health and education policies suitable for each population. Objective: This study aimed to describe the risk of death in SARS-COV2 infected subjects by age group and according to the presence of comorbidities. Methods: We analyzed data of confirmed SARS-COV2 infection cases where symptoms began between February 22th, 2020, and April 18th, 2021, as published by the General Epidemiology Direction (DGE) of the Mexican Ministry of Health. We calculated COVID-19 incidence and mortality by age group using population data from the Statistics and Population National Institute (INEGI), and estimated the association between risk of death and the presence of comorbidities. Results: Mortality in SARS-COV2 infected people varied considerably, between 7 and 155 deaths per million per year in the under-20 age groups compared to 441 to 15,929 in the older age groups. Mortality in pediatric populations is strongly associated with comorbidities (OR: 4.6-47.9) compared to the milder association for older age groups (OR: 3.16-1.23). Conclusion: The risk of death from SARS-COV2 infection in children is low and is strongly associated with comorbidities., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 González-García, Castilla-Peón, Solórzano Santos, Jiménez-Juárez, Martínez Bustamante, Minero Hibert and Garduño-Espinosa.)

The pandemic caused by the new coronavirus Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is currently affecting more than 200 countries. The most lethal clinical presentation is respiratory insufficiency, requiring attention in intensive care units (ICU). The most susceptible people are over 60 years old with comorbidities. The health systems organization may represent a transcendental role in survival. Objective: To analyze the correlation of sociodemographic factors, comorbidities and health system organization variables with survival in cases infected by SARS-CoV-2 during the first 7 months of the pandemic in Mexico. Methods: The cohort study was performed in a health system public basis from March 1st to September 30th, 2020. The included subjects were positive for the SARS-CoV-2 test, and the target variable was mortality in 60 days. The risk variables studied were: age, sex, geographic distribution, comorbidities, health system, hospitalization, and access to ICU. Bivariate statistics ( X 2 -test), calculation of fatality rates, survival analyses and adjustment of confusing variables with Cox proportional-hazards were performed. Results: A total of 753,090 subjects were analyzed, of which the 52% were men. There were 78,492 deaths (10.3% of general fatality and 43% inpatient). The variables associated with a higher risk of hospital mortality were age (from 60 years onwards), care in public sectors, geographic areas with higher numbers of infection and endotracheal intubation without management in the ICU. Conclusions: The variables associated with a lower survival in cases affected by SARS-CoV-2 were age, comorbidities, and respiratory insufficiency (with endotracheal intubation without care in the ICU). Additionally, an interaction was observed between the geographic location and health sector where they were treated., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Márquez-González, Méndez-Galván, Reyes-López, Klünder-Klünder, Jiménez-Juárez, Garduño-Espinosa and Solórzano-Santos.)

Background and Objective: Diseases of the respiratory system represent one of the leading causes of medical care and antibiotic prescriptions. Currently, new technologies are used for the diagnosis of respiratory diseases of viral origin, such as the FilmArray Respiratory Panel ® , approved in 2012 by the FDA. The purpose of this study was to identify the correlation between the diagnosis and treatment of respiratory tract infections and the result of the polymerase chain reaction test for respiratory viruses., Material and Methods: The study is of a retrospective, cross-sectional, descriptive type. One-hundred and thirty-four patients who underwent a viral panel for respiratory viruses, which was positive for one or more viruses, were included. For all cases, the positive results of said test and the treatment received by patients were analyzed., Results: Of the patients who underwent nasopharyngeal aspirate during hospitalization, 58 % received antibiotic treatment at admission, 13 % received combined treatment (antibiotic + antiviral), 27 % of the patients received symptomatic treatment since admission and 2 % did it with antivirals. After receiving a positive result for respiratory viruses, 38 % continued with antibiotics, 30 % with antibiotics and antivirals, 13.8 % were managed only with antivirals and 18.2 % with symptomatic treatment., Conclusion: Despite the global alert regarding antimicrobial resistance, patients continue to be treated with antibiotics, due to a situation that we ignore, but that is believed to be influenced by several factors., (Copyright: © 2021 Permanyer.)

Objective: To establish the current situation of antimicrobial resistance and antibiotic consumption in Mexican hospitals., Materials and Methods: Antimicrobial susceptibility data from blood and urine isolates were collected. Defined daily dose (DDD) of antibiotic consumption/100 occupied beds (OBD) was calculated., Results: Study period: 2016 and 2017. Of 4 382 blood isolates, E. coli and K. pneumoniae were most frequently reported, with antimicrobial resistance >30% for most drugs tested, only for carbapenems and amikacin resistance were <20%. A. baumannii had antimicrobial resistance >20% to all drugs. Resistance to oxacillin in S. aureus was 20%. From 12 151 urine isolates, 90% corresponded to E. coli; resistance to ciprofloxacin, cephalosporins and trimethoprim/sulfamethoxazole was >50%, with good susceptibility to nitrofurantoin, amikacin and carbapenems. Global median antimicrobial consumption was 57.2 DDD/100 OB., Conclusions: s. This report shows a high antimicrobial resistance level in Gram-negative bacilli and provides an insight into the seriousness of the problem of antibiotic consumption., Competing Interests: Declaration of conflict of interests. The authors declare that they have no conflict of interests.

Measles is an exanthematous disease caused by a virus of the Morbillivirus genus. On February 23, 2020, the exanthema began in the first confirmed case of measles this year. At the same time, on February 28, 2020, the first case of the new coronavirus disease (COVID-19) was confirmed. Up to June 6, 2020, 176 measles cases have been confirmed: 137 in Mexico City, 37 in the state of Mexico, and two in the state of Campeche. In Mexico City, municipalities with more cases were Gustavo A. Madero, Miguel Hidalgo, and Iztapalapa; in the State of Mexico were Ecatepec, Tlalnepantla, and Netzahualcoyotl; in Campeche, there are only two cases reported. On the other hand, 7,065,133 cases of COVID-19 have been registered worldwide with a global case fatality rate of 5.7%. In Mexico, there have been 113,619 confirmed cases and 13,511 deaths, while in Mexico City, there have been 30,223 cases and 3062 deaths. Iztapalapa and Gustavo A. Madero are the locations with more cases reported. Hence, a campaign of social distancing started as part of the strategies to control the spread of the infection. The potential threat is that as social confinement measures are relaxed and mobility is initiated, both viruses could continue to spread. It is expected that due to the time that has passed since the last reported measles case, control of this disease will be achieved., (Copyright: © 2020 Permanyer.)

Background: In Mexico, 70.6% of serotypes causing invasive pneumococcal disease were covered since the application of the PCV13 vaccine in children under 5 years of age. After several years of immunization, cases of disease caused by the serotypes included in the vaccine have decreased. However, a replacement due to serotypes not included in the vaccine has been observed., Case Report: Three cases of pediatric patients who developed invasive disease due to serotypes not included in PCV13 are described: one with meningitis and bacteremia (serotype 15C), and two with pneumonia, of which one complicated with effusion (serotype 35B). Patients were treated in a pediatric hospital in Saltillo, Coahuila, from 2015 to 2018., Conclusions: Three serious cases due to serotypes of Streptococcus pneumoniae not included in PCV13 were reported in a single pediatric hospital in a northern state of Mexico. This phenomenon is taking place nationwide and worldwide an increase of cases of invasive disease due to pneumococcal serotypes not included in the vaccine currently used., (Copyright: © 2019 Permanyer.)

Background: Severe infections due to Streptococcus dysgalactiae subsp. equisimilis (SDSE) have been identified in adults and may cause toxic shock syndrome, although with a low frequency., Case Report: A preschool-age female patient, who started with an upper respiratory tract infection developing a gradual deterioration in the following three days, is described. She was admitted to the hospital in severe conditions, with tachypnea, tachycardia (200/min), hypotension (blood pressure 68/40 mmHg), capillary refill of 7 s, and erythematous maculopapular rash in thorax, abdomen and lower extremities. She received intensive management with an inadequate response. Furthermore, she developed multiple organ failure and died 8 h after admission. The blood culture was positive for S. dysgalactiae subsp. equisimilis., Conclusions: SDSE is a rare pathogen in children. In Mexico, cases of SDSE have not been reported probably due to an inaccurate identification. Mexican pediatricians should be alert to this situation.., (Copyright: © 2019 Permanyer.)

Background: Ambulatory therapy in low-risk patients with cancer, fever, and neutropenia seems to be a secure and effective alternative. This study aimed to compare the effectiveness and safety of the antimicrobial treatment in early discharge vs. in-hospital treatment in children with cancer and febrile neutropenia (FN) with low risk of invasive bacterial infection (IBI)., Methods: Quasi-experimental design with a historical cohort control group. Children with cancer during an episode of FN and low risk of IBI were included. The control group were inpatient children that received intravenous piperacillin/tazobactam. The experimental group was early discharge patients, who received 48 h of IV treatment and were switched to oral treatment. Outcomes: fever resolution, readmissions, and mortality., Results: Eighty low-risk FN episodes were included; the median age was 6 years old (2.6-11 years), and 43 (54%) were female. Main diagnoses were solid tumors (52 patients) and leukemia or lymphoma (28 patients). Forty-three patients received in-hospital treatment, and 37 were selected for early discharge (31 patients received ciprofloxacin and six received amoxicillin/clavulanate). Two patients were readmitted, one due to a relapse of fever with tumor progression and the other due to epistaxis. Adverse effects occurred in 21.6% of the early discharge group and 12% of the inpatient treatment group (p = 0.04)., Conclusions: Early discharge in pediatric patients with cancer, fever, and neutropenia is an acceptable and safe alternative for low-risk patients., (Copyright: © 2018 Permanyer.)

Introducción: La fiebre manchada de las montañas rocosas (FMMR) es causada por Rickettsia rickettsii. En Coahuila, la región de la Comarca Lagunera se considera una zona endémica. No se han reportado casos en la zona sur del estado, específicamente en la ciudad de Saltillo., Métodos: Estudio prospectivo, reporte de casos. Se incluyeron los casos de niños atendidos en el Hospital del Niño Dr. Federico Gómez Santos en la ciudad de Saltillo, Coah., del mes de septiembre de 2012 a septiembre 2017 con diagnóstico confirmado clínicamente y por reacción en cadena de la polimerasa (PCR) de FMMR. Se presentan los antecedentes epidemiológicos, las características clínicas y evolución de los pacientes., Resultados: Se confirmaron 14 pacientes. La relación masculino:femenino fue de 1.8:1, la edad promedio de los pacientes fue de 7.6 años (18 meses a 13 años). El 42.8% de los pacientes refirió el contacto con perros y el 57.1% afirmó tener contacto con garrapatas. En todos los casos hubo fiebre y exantema purpúrico; alrededor del 70% manifestaron mialgias y artralgias; el 28% tuvo sangrado del tubo digestivo, y el 11% alteraciones neurológicas graves. El 64.2% de los casos recibió tratamiento adecuado con doxiciclina. Fallecieron 8 pacientes, con una tasa de letalidad de 57.1%., Conclusiones: La zona sur de Coahuila debe considerarse una zona endémica para FMMR. El retraso en el diagnóstico y tratamiento favorecen una mayor letalidad., Background: Rocky Mountain Spotted Fever (RMSF) is caused by Rickettsia rickettsii. In Coahuila, Comarca Lagunera is considered an endemic zone; no cases have been reported in the southern zone of the state, specifically in the city of ­Saltillo., Methods: Prospective study, cases report. Children evaluated in the Hospital del Niño Dr. Federico Gómez Santos from September 2012 to September 2017, with clinically and laboratory (by polymerase chain reaction, PCR) confirmed diagnosis of FMMR were included. The epidemiological antecedents, clinical characteristics and patient’s evolution are presented., Results: 14 patients were confirmed. The male: female ratio was 1.8: 1, the average age of the patients was 7.6 years (18 months to 13 years). 42.8% reported contact with dogs and 57.1% confirmed contact with ticks. In all cases, there was fever and purpuric rash; around 70% manifested myalgias and arthralgias; 28% presented digestive tract bleeding and 11% had severe neurological alterations. 64.2% of the cases received adequate treatment with doxycycline. Eight patients died with a case fatality rate of 57.1%., Conclusions: The southern zone of Coahuila should be considered an endemic area for FMMR. The delay in diagnosis and treatment favor a greater lethality., (Copyright: © 2018 SecretarÍa de Salud.)

Introduction: On April 2009, the Mexican Ministry of Health received notification of cases of severe pneumonia mostly affecting young healthy people; this was the beginning of the first influenza pandemic of the 21st century. The nature of the immune response to the influenza A(H1N1)2009 pandemic strain in Mexico at the beginning of the pandemic outbreak has not been completely defined. We describe the serological response to the 2009 pandemic influenza virus in paediatric patients with influenza-like illness, their household contacts (HHCs), and exposed health-care workers (HCWs) at the beginning of the pandemic outbreak in Mexico City., Methodology: thirty pre-epidemic and 129 epidemic samples were collected and serum antibodies were measured against A(H1N1)2009 pandemic virus and two non-pandemic swine influenza viruses by an haemagglutination inhibition assay ., Results: 91% (29/32) of the convalescence samples from confirmed patients had an antibody titre ≥ 10 (GMT 25), 63% (41/65) of the HHCs (GMT 12), 41% of HCWs (GMT 6) and 13% (4/30) of pre-epidemic samples (GMT 6) for the pandemic influenza virus. Of the 32 confirmed cases, 60% had an antibody titre ≥ 40 for the pandemic strain, 53% for the A/swine/Iowa(H1N1) virus (GMT 62) and 43% for the A/swine/Texas(H3N2) virus (GMT 66)., Conclusion: The antibody response to 2009 pandemic influenza virus was widespread in convalescence samples from patients with confirmed pandemic influenza infection but the GMT was below the protective titre. There was no evidence that antibodies to the swine influenza viruses had cross-protective effect against the 2009 pandemic influenza virus.

Background: Pandemic influenza A (H1N1) virus was first reported in April 2009. The aim of this study is to describe the clinical course of patients with influenza-like illness treated in a tertiary care pediatric hospital., Methods: Cross-sectional analytical study, encompassing the period from April 2009 to March 2010. Clinical and demographic information was obtained from clinical records. Data analysis was carried out using descriptive statistics, using a univariate analysis with the chi-square test, the exact Fisher test, and the Mann-Whitney U test for quantitative variables., Results: 240 patients were included, out of which 53.9 % were female; median age was 5 years. Sixty four cases (26.6 %) were confirmed, 38 % had and underlying condition, and 10 % had received the influenza vaccine. One hundred and sixteen patients (48 %) were hospitalized. With regard to mortality, 10 out of 64 confirmed cases died, 3 of the 86 of the disregarded cases, and 2 of 90 without a confirmatory test died (p < 0.05). The patients who died started antiviral treatment on day 7; conversely, those who survived started the treatment on day 4 (p < 0.05)., Conclusions: Lethality was higher in patients with confirmed infection. Antiviral treatment within the first 48 hours was observed to be essential for patients with risk for the development of complications.

Objective: to determine frequency, serotypes, biotypes and susceptibility to eight antibiotics in Haemophilus influenzae nasopharyngeal isolates in children under five years old from Mexico City., Methods: cross-sectional survey including children two months to five years old. A nasopharyngeal sample was taken. Haemophilus influenzae identification, serotyping, biotyping and antimicrobial susceptibility were performed., Results: a sample of 573 children were included. In 88/573 (15.3 %) H. influenzae was isolated, corresponding in 7/573 (1.2 %) to Hib, 3/573 (0.5 %) to Hi a, c, d, f and 78/573 (13.6 %) to Nontypable Hi. Among Hib carriers, 6 had received only one or two doses of specific vaccine. Biotype VIII (76.1 %) was the predominant. All isolates were susceptible to the antibiotics, but one Hib strain was resistant to erithromycin., Conclusions: nontypable Haemophilus influenzae was predominant. Colonization by Hib in children under 5 years old was low (1.2 %), occurring in children with an incomplete vaccination schedule.

Objectives: To identify factors associated with root caries development in a 12- month period, in an elderly Mexican population, so as to develop a prediction model for the occurrence of root caries., Methods: A case-cohort study was carried out with 698 randomly selected beneficiaries of the Mexican Institute of Social Security (IMSS), residing in the southeast of Mexico City. Initially, base line (t₀) data regarding sociodemographic variables, general health, general and oral healthy habits, salivary conditions, cariogenic microorganisms and oral health clinical indicators were collected. Twelve months from the date of the first clinical evaluation (t₁), a new examination was carried out to determine the root caries increment. Variables that showed a significant association (P ≤ 0.05) with the root caries increment were included in the prediction model., Results: Six hundred and ninety-eight elderly subjects were included in the cohort (t₀), with 76.1% (n = 531) of the elderly patients followed up at 12 months (t₁). Incidence of root caries was 21.7% (n = 115), a mean root caries increase of 0.4 (1.0) surfaces. The variables, DLBA limitations (Yes), smoking (Yes), mouthwash (No), Mutans streptococci (≥10⁵ CFU/ml), healthy root surfaces (≥6) and Root Caries Index (≥8%), showed a statistically significant association (P < 0.05). This model showed a correct classification in 80.0% (n = 425) and an area under the Receiver Operating Characteristic curve of 0.75., Conclusions: This is a good prediction model for the 12 months root caries increment in this population of elderly Mexicans., (© 2010 John Wiley & Sons A/S.)

Background: The ongoing influenza A (H1N1) pandemic stroked Mexico and posed a huge challenge to the medical care and public health systems. This report analyzes the clinical course and process of care of patients who died due to atypical pneumonia and fulfilled the clinical criteria of suspected case of novel influenza A (H1N1) virus infection., Methods: We conducted a retrospective analysis of a series of 38 patients who died between April 7 and April 28, 2009 at Instituto Mexicano del Seguro Social (IMSS) hospitals due to severe pneumonia and respiratory distress. These cases coincided with the beginning of the outbreak, so patients did not undergo laboratory testing to diagnose influenza. According to IMSS and CDC criteria, post-hoc analysis allowed considering the presumptive diagnosis of S-OIV infection. A multidisciplinary group analyzed the information from the clinical charts, laboratory tests, radiographic studies and death certificates, using descriptive statistics., Results: Most cases were middle-aged (mean 33 years, range: 4-62 years) and previously healthy; 18.4% had an underlying chronic disease, 23.7% were obese and 7.9% were current smokers. None had received the seasonal influenza vaccine; they had cough (92%), fever (86.8%), and malaise (73.7%). The median time from disease onset to hospital admission was 6 days (range 0-8 days). All were admitted to the intensive care unit with pneumonia and/or respiratory distress. Average time from disease onset to death was 8 days (range 4-18 days)., Conclusions: An increased number of severe cases of atypical pneumonia in previously healthy adults highlight the importance of the availability of a timely surveillance system able to identify sudden increases in the number of cases or presentation of apparently known diseases.

Introduction: Twenty years ago, prevalence of Hepatitis A in Mexican children was 90%., Objective: To describe a shift in the prevalence of Hepatitis A virus (HAV) infection and to demonstrate an increment in the age at the first contact with HAV, in a sample of Mexican children., Material and Methods: Reports of antiviral serologic studies collected from 1991 to 2005 from patients attending a pediatric hospital, were reviewed, and those with IgM anti-HAV positive in serum were selected. Age at the moment of acute infection was analyzed. Additionally, a serological survey searching IgG anti-HAV was made in a group of HAV unvaccinated children., Results: From 1708 determinations of IgM, 221 were positive (13%). According to the year of report, five groups were constituted. Mean age by group was: 1991-1993 of 6.4 years, 1994-1996 of 8.0, 1997-1999 of 8.4, 2000-2002 of 8.0 and from 2003-2005 of 10.1 years. In a cohort of 259 unvaccinated children (mean of age 8.59 years), IgG antibodies were detected in 51%., Conclusion: In the infantile population studied a Hepatitis A epidemiology shift is suggested.

Four patients who had received tick bites while visiting forests in Mexico had skin lesions that met the case definition of erythema migrans, or borrelial lymphocytoma. Clinical diagnosis was supported with histologic, serologic, and molecular tests. This study suggests the Borrelia burgdorferi infection is in Mexico.

Aim: The aim of this study is to describe the percentile distribution of the waist circumference in Mexican pre-pubertal children living in an urban, middle-income area., Methods: Children, aged 6-10, from a primary school, located in a middle-income area in Mexico City were included (n=833). Anthropometric measurements were made in the case of all children by using standardized procedures., Results: The prevalence of obesity and overweight was greater among boys (p<0.001). Of them, 30 were obese (7.2%) and 47 were overweight (11.4%). Girls had a prevalence of obesity of 2.8% and of overweight of 8.8%. Boys had greater waist circumference than girls (p<0.001). This observation was independent from differences in age or body mass index (BMI). The distribution of the waist circumference was shifted towards higher values among boys. The values corresponding to the 85th percentile ranged, in boys aged 6-10, between 62.9 and 85.9 cm. By contrast, for girls, those values were 66.8 and 72.08 cm, respectively. A receiver-operator curve was constructed in order to identify the waist circumference most likely to be associated with a BMI of > 85th percentile. We found that age- and sex-specific cut-off points are required for the detection of central adiposity in children aged 6-10., Conclusions: The percentile distribution of the waist circumference in Mexican pre-pubertal children living in urban, middle-income areas is described in this study. Moreover, included are the cut-off points most likely to be associated with increased adiposity. This information can be used for defining abdominal obesity in paediatric populations.

Locally prevalent pathogenic bacteria 189 Gram (-) and 135 Gram (+) strains, all isolated from pediatric patients severely infected, were tested in vitro against 11 essential oils from commercial origin. All the strains showed resistance to selected antibiotics. Cinnamomum verum, Origanum vulgare and Thymus vulgaris exhibited the highest and broadest antibacterial activity. Emphasis is made in the potential implications of these resources, uncommon at the clinical setting of the study, employed against non-commercial, locally pathogenic strains, being a step to submit in the ensuing period essential oils from plants used in Mexican traditional medicine.

Objective: To determine the frequency, serotypes and susceptibility profiles to eight antimicrobials in Streptococcus pneumoniae nasopharyngeal isolates from a representative sample of children under 5 years of age, residents of Mexico City., Patients and Methods: A cross-sectional survey was conducted in 573 children aged 2 months to 5 years.A nasopharyngeal sample was taken. S. pneumoniae identification, capsular serotyping and antimicrobial susceptibility to eight antimicrobials were performed according to standardized methods., Results: S. pneumoniae was isolated in 122/573 (21.4%) children. The most frequent capsular serotypes were 23F, 35, 19F, 11A and 15A; 46% of isolates corresponded to serotypes not included in the heptavalent vaccine. Low penicillin susceptibility was found in 12% of strains with 3% of highly resistant penicillin strains; erythromycin resistance was >30% and trimethoprim-sulfamethoxazole resistance >40%. None of the isolates was resistant to vancomycin, cefotaxime, amoxacillin-clavulanate, chloramphenicol or ampicillin., Conclusions: Several S. pneumoniae serotypes from nasopharyngeal carriers are not included in the heptavalent vaccine. Resistance to trimethoprim-sulfamethoxazole and macrolides is high. The medical community should be aware of these results.

Between 1997 and 2000 a single multidrug-susceptible methicillin-resistant Staphylococcus aureus clone, M (sequence type 30 [ST30]-staphylococcal cassette chromosome mec [SCCmec] type IV), was present in a pediatric hospital in Mexico City, Mexico. In 2001 the international multidrug-resistant New York-Japan clone (ST5-SCCmec type II) was introduced into the hospital, completely replacing clone M by 2002.

Objective: To detect serological evidence of B burgdorferi infection in individuals from Mexico City and from the Northeast Region of the country., Material and Methods: A representative sample size of serum from Mexico City and the states of the Northeast of Mexico were taken from serum samples corresponding to the 1987-1988 national survey were obtained from the National Serum Bank. Antibodies against B burgdorferi were detected by ELISA and confirmed with Western blot (WB) assays. Data were analyzed using descriptive statistics., Results: A total of 2,346 serum samples were tested; 297 (12.6%) were positive for ELISA, and 122 of 297 were confirmed by WB. Seroprevalence was 3.43% in Mexico City and 6.2% in the Northeast region of the country. Tamaulipas was the state with the highest seroprevalence., Conclusions: The prevalence of seropositive cases shows that borrelial infection is present in the northeast of Mexico and Mexico City. Identification of clinical cases and infected tick vectors is necessary to confirm the presence of Lyme disease in Mexico.

Objective: To assess the prevalence of IgG antibodies against Group B streptococci (GBS) among women of reproductive age in Mexico., Material and Methods: Serum specimens were drawn from 15 to 40 year-old women, representative of all regions and socioeconomic levels of the country. The sample was randomly selected from Banco Nacional de Sueros (National Sera Bank); serum samples were collected during a national seroepidemiologic survey conducted in 1987-1988. The assays for standardization and for evaluation of seroprevalence were carried out at the Hospital de Pediatría del Centro Médico Nacional Siglo XXI (Children's Hospital) Instituto Mexicano del Seguro Social (IMSS) (Mexican Institute of Social Security) from January to November 1995. IgG antibodies against group B antigen were studied with an enzyme-linked immunosorbent assay (ELISA) developed in our lab. Group B antigen was produced and purified from the reference strain GBS 110., Results: A total of 2669 serum samples were studied; 2405 were positive to anti-group B antigen IgG antibodies, for a seroprevalence of 90.2%. No differences in prevalence were found among the different age groups or among the different states of the country., Conclusions: The high seroprevalence of antibodies against GBS suggests that young women in Mexico are commonly exposed to GBS infection.

Unlabelled: Congenital rubella syndrome (CRS) has been considered an uncommon problem in Mexico., Objective: To analyze and describe clinical features of CRS cases in infants from a pediatric hospital in Mexico City during an 8 year period., Design: retrospective study. Patients younger than 18 months of age with a positive serologic test for IgG and IgM rubella antibodies were included. Antibodies were measured by an immunoenzymatic microparticles assay., Results: Fifty-six cases were identified, 42 complete clinical records were available for review. Of these, 23 (54.7%) were female and 19 (45.3%) male. Median for age was five months. A total of 9/42 mothers (21%) had history of rash during pregnancy. IgM antibodies were detected in 15 infants and IgG in 27. Major manifestations were ocular (74%), neurologic (66%), and congenital heart disease (67%). Congenital cataracts were detected in 69%, in 52% hepatomegaly, in 43% jaundice, in 40% anemia, in 48% thrombocytopenia, and hearing loss 19%., Conclusion: Five confirmed cases with CRS per year in one hospital indicate a high frequency. Only a small percentage of women had a history of rash during pregnancy. CRS must be investigated in infants with ocular, neurologic, and congenital heart diseases.

Objective: To determine the prevalence of upper respiratory tract colonization by Moraxella catarrhalis in children under six years of age., Material and Methods: A survey was conducted between January and December 1998 in Mexico City, among children aged 2 months to 5 years, selected through cluster sampling. Pharyngeal samples were taken for M. catarrhalis identification. The minimal inhibitory concentration to different antibiotics was obtained and beta-lactamases were determined by the iodometric test. Statistical analysis consisted of frequency distributions, odds ratios, 95% confidence intervals, and Mantel-Haenszel chi 2. Statistical significance was set at p < 0.05., Results: After excluding 37 children, the study population was 604 children from Mexico City; M. catarrhalis was present in 130 pharyngeal specimens (22.9%). Most of the strains were positive for beta-lactamase production (75.4%). Eighty percent of the strains was resistant to penicillin and 70% to ampicillin and amoxicillin. None were resistant to cefotaxime, imipenem, meropenem and erythromycin., Conclusions: Prevalence of M. catarrhalis upper respiratory tract colonization is similar to that of other respiratory pathogens. These findings warrant future research on the role of M. catarrhalis as an etiologic agent in acute and chronic respiratory infections in Mexico.

Unlabelled: Cryptosporidium parvum is associated with diarrheic disease and mainly affects children and immunocompromised hosts. In most of the cases, cryptosporidiosis infection is asymptomatic in immunocompetent subjects. The objectives of the study were to determine the frequency of asymptomatic infection caused by the parasite in children with and without malnutrition and to determine the risk factors associated to infection., Methods: Children from one to fifteen years old without diarrhea were included, somatometry were performed. The socioeconomic and sanitary conditions were investigated for each family and community. The Faust method and Kinyoun stain were employed identify parasites and Cryptosporidium parvum in feces. Odds ratio (OR), 95% confidence intervals (75% CI), chi 2 Mantel-Haenszel, Fisher exact test and chi 2 trends were calculated., Results: One hundred thirty two children were included. In 10/132 (7.5%) cysts of Cryptosporidium were found, 7/71 in children with malnutrition (9.8%) and 3/61 without malnutrition (4.9%) p = 0.23. 69.7% of the children had parasitosis. According to the presence of C. parvum in feces, the different factors calculated were: Diarrhea in family OR = 5.82 (95%IC 0.86-39.18), not hand washing OR = 5.08 (95%IC 0.62-110.49), age less than 5 years old OR = 4.90 (95%IC 0.60-106.9), drinking non-potable water OR = 3.34 (95%IC 0.40-73.01) and malnutrition 2.11 (95%IC 0.46-10.89). Association was found between the number of people in the same house and the risk of infection (p = 0.005). The presence of diarrhea in the family (OR = 4.15, 95%IC 0.47-36.91) and drinking non-potable water (OR = 4.19, 95%IC 0.48-36.32) were the significant factors in the regression logistic model., Conclusions: The frequency of Cryptosporidium infection were 7.5%. Diarrhea in the family, overcrowding and drinking non-potable water were associated with C. parvum infection, malnutrition was not a significant risk factor.

Objective: To know the cost generated by nosocomial infections, to establish the proportion of the total hospital budget used in extra-days of stay, drugs, laboratory and others items used for the treatment., Methods: We studied 131 nosocomial infections in 82 patients attended in hospital's departments from June to August 1995. We evaluated days of stay, type of infection, episodes per patient, drugs, laboratory, and others items used in the treatment of nosocomial infections. We took percentage of cost of every point and the mean of the total cost generated by year cause nosocomial infections and a cost per infection in every department., Results: The total overtime of stay was 970 days, mean per infection was 7.4. Totals days of antimicrobials was 974, mean was 11.9 days per infection. The hospital processed 410 laboratory studies, 191 cabinet studies. The total cost generated by overtime stay was $3,415,860.00, and considering also drugs, laboratory and cabinet studies $3,516,421.00., Conclusions: The cost of the nosocomial infections depends on the overtime stay, drugs, laboratory and cabinet studies needed for their treatment. Neonatology generated presented more than one infection generating higher cost. Total cost in 3 months was $3'516,421.00, nosocomial infections would take $14'065,684.00 in a year, involving 12.1% of the hospital total budget. Preventive measures must be taken trying to diminish these costs.

Objective: To describe the results of an epidemiologic surveillance program, from 1990 to the first semester of 1997, in a new high-specialty pediatric hospital and perform a comparison with previous reports., Material and Methods: The total number and type of nosocomial infections, the incidence rate and density incidence for department and division, for different age groups and according to immune statues were registered., Results: The global incidence of nosocomial infections during the period was 25.7 per 100 discharges, with a progressive decrease during the last three years. Although immunocompromised patients had more infections than immunocompetent ones, the difference was not significative. The three most common infections were: pneumonia, vascular line infections and upper respiratory tract infections. It is possible that upper respiratory tract infections are contributing to the elevation of global incidence rates of nosocomial infections., Conclusions: The change of infection epidemiology regarding previous experience has led to the implementation of programs to prevent the most frequent problems. It is necessary to intensify the different prevention programs and to increase their reach in order to cut down costs in a short term.

During a surveillance study to determine the relative prevalence of capsular types of Streptococcus pneumoniae and antimicrobial susceptibility of invasive isolates in children <5 years old in Mexico City, 220 isolates were collected. The serotype 23F was the most common found, followed by types 6A + B, 14, 19F, and 19A. Diminished susceptibility to penicillin was detected in 106 isolates (48.2%), and high penicillin resistance was found in 49 strains (22.2%), 31 belonging to type 23F. Resistance was also observed to erythromycin (13.1%), to chloramphenicol (43.1%), and to cefotaxime (10.9%). No strains were resistant to ofloxacin or vancomycin. Forty-four of the highly penicillin resistant isolates (penicillin MIC > or =2.0 microg/ml) were examined with molecular fingerprinting techniques; 29 (65.9%) of these isolates (all except two strains) were serotype 23F and shared subtype variants of PFGE type A characteristic of the internationally spread Spanish/USA clone of S. pneumoniae. These strains were also resistant to trimethoprim/sulfametoxasole (TMP/SMX), chloramphenicol, and tetracycline, and most of them were susceptible to erythromycin. Another 6 of the highly penicillin-resistant strains (serogroups 9 and 14) showed PFGE fingerprints and antimicrobial susceptibility pattern characteristic of a second internationally spread clone (French/Spanish clone) and carried resistance to penicillin and TMP/SMX. The rest of the 9 penicillin-resistant isolates were represented by 7 distinct additional PFGE types. The findings suggest that almost 80% of all highly penicillin resistant strains may have been "imported" into Mexico.

Objective: To analyze an outbreak of Serratia marcescens in a neonatal intensive care unit and identify the risk factors associated to the development of infection., Material and Methods: It was a case-control study from March to July 1995. Factors included were age, sex, intravascular devices, nebulizers, mechanical ventilation, use of total parenteral nutrition (TPN), underlying diseases, surgical interventions, tubes, previous antimicrobial treatment and days of exposure. The associations were explored using the odds ratio., Results: 24 cases and 30 controls were included. In the univariate analysis the significant risk factors (OR,IC) were use of central venous catheter (4.57, 1.01-23.5), days of use of TPN (4.38, 1.03-16.5), days of previous antimicrobial treatment (4.87, 1.60-22) and days of exposure (2.7, 2.65-27.6). In the multivariate analysis the significant risk factors were previous antimicrobial treatment (3.98, 2.36-18.2), days of previous antimicrobial treatment (6.76, 3.02-24.6) and days of use of TPN (4.87, 1.67-15.6)., Conclusions: The significant risk factors in our study were previous antimicrobial treatment, days of antimicrobial and days of use of TPN.

As part of the Sistema Regional de Vacunas (SIREVA) initiative, we conducted a surveillance study to determine the relative prevalence of capsular types of Streptococcus pneumoniae and antimicrobial susceptibility of invasive isolates in children less than 5 years old. We collected 220 isolates and found 33 of the 90 known types, with type 23F as the most common followed by types 6A+B, 14, 19F, and 19A. High penicillin resistance was found in 49 strains (22.2%), 31 belonging to type 23F. Twenty-nine (13.1%) were resistant to erythromycin, 95 (43.1%) were resistant to chloramphenicol, and 24 (10.9%) were resistant to cefotaxime. No strains were resistant to vancomycin.

Eight-three isolates of Streptococcus pneumoniae obtained from children hospitalized with several infections in Mexico City and Cuernavaca, and from healthy children attending a day-care center in Cuernavaca, from January to September 1992, were screened for antimicrobial resistance patterns by in vitro susceptibility testing against antimicrobial agents of potential use in the treatment of diseases caused by S. pneumoniae (39 infected patients and 44 from healthy children). 21.6% of strains were resistant to penicillin, 52% of the strains were multiresistant without a commun pattern. Children attending a day-care center had a higher rate of S. pneumoniae strains resistant to one or more antimicrobial than hospitalized children. Serotypes or serogroups 6, 23F, 14 and 19 were most prevalent. There are evidence that strain 23F has an intercontinental link, this strain is associated with disseminated diseases and multiresistance to antimicrobials. The results indicate that changes can occur in the susceptibility of S. pneumoniae and that selective susceptibility testing and epidemiologic studies in hospitalized patients and children in day-care centers are necessary.

Visceral leishmaniasis is a rare parasitosis in our country; in a 30 year period only exists the report of five cases, three in the state of Puebla and two in the state of Guerrero. Now it has been identified another two cases in the state of Chiapas. In these patients the common presentation of the disease were fever, hepatosplenomegaly, hypergammaglobulinemia and pancytopenia. The parasite can be found in liver, spleen, lymph nodes and bone marrow macrophages. A definitive diagnosis depends on the demonstration of the parasite in tissue; spleen biopsy is the most useful because it is positive in 98% of the cases, in other tissues the amastigotes are seen in 50-80% of the cases. Negative PAS-stained smears maintains the diagnosis until another more specific method as electronic microscopy or culture is available. Pentavalent antimonial compounds are the drugs of choice and as an alternative or in case of failure amphotericin B can be used.

The authors report a nosocomial infection outbreak by Klebsiella pneumoniae, observed in neonates at a gyneco-obstetrical hospital from Mexico City. Forty six newborns presented one or more infections due to K. pneumoniae during their stay in neonatal care units, between October 3 and November 12, 1988. Sepsis was documented in 41 cases by clinical picture and routine laboratory exams, including one positive, blood culture at least. The most frequent invasive procedures practiced in these patients were catheterization and ventilatory support. K. pneumoniae was isolated as well from several environmental sources that could have led to infection of patients. Treatment of cases was initiated with ampicillin-amikacin, however, therapeutic failure with a lethality rate of 50% (14/28) and results of antimicrobial susceptibility conducted to treatment with cefotaxime. Fifteen out of 19 patients receiving the cephalosporin survived. To prevent outbreaks like the one presented here, we concluded that appropriate measures dealing with hygiene and education of personnel plus monitoring of bacterial susceptibility to antimicrobials, should prove successful in our environment.

In order to know the etiology of purulent meningitis in infant and children, a retrospective study was done; 709 cases of a pediatric infectious disease service were analyzed. Diagnosis was established either by antigen detection (coagglutination) or bacterial culture. In 334/709 (48%) the bacterial agent was identifies. Haemophilus influenzae type b (70%), Streptococcus pneumoniae (14%), Enterobacteriaceae (8%) and Streptococcus sp (6.5%) were the most frequent. According to our results the epidemiologic pattern of purulent meningitis has not changed. A therapeutic approach is suggested.