[Prevalence of Moraxella catarrhalis colonization in asymptomatic carriers under 6 years of age]. / Prevalencia de colonización por Moraxella catarrhalis en portadores asintomáticos menores de seis años.

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.

[Prognosis of rotavirus diarrhea]. / Pronóstico de la diarrea por rotavirus.

OBJECTIVE: To compare the severity of rotavirus diarrhea (RV) and non-rotavirus diarrhea. MATERIAL AND METHODS: Between October 1994 and March 1995, a cross-sectional study was performed in 520 infants with acute diarrhea, at seven primary care level centers in five states of Mexico. Diagnosis of RV was done through immunoenzymatic assay or electrophoresis. Central tendency measures were used for data analysis. Results were presented as means and standard deviations, or median and variation. RESULTS: RV was isolated from 264 children; most of them were males aged 6 months to 1 year. Differences in clinical manifestations were statistically significant between the rotavirus-positive group and the rotavirus-negative group, in the following variables: median number of stools/24 hours; frequency of vomiting; temperature > 38 degrees C; dehydration; and clinical severity scoring. CONCLUSIONS: These results showed a poorer prognosis and a higher severity of rotavirus diarrhea, as compared to non-rotavirus diarrhea in infants.

The day care center as a risk factor for acute respiratory infections.

BACKGROUND: This study was conducted to assess the magnitude of the risk of high morbidity (> or = 7 episodes/year) for acute respiratory infections (ARI) in infants attending day care centers (DCC), and to compare the incidence, duration, and severity of ARI in children staying at home (Home). METHODS: Using a cohort design, 282 infants (DCC, 138 and Home, 144) were followed for a year. Age at entry into the study ranged from 43 days to 4 months. During follow-up, social workers interviewed the mothers weekly to register whether the infants had an ARI. Also, infant health conditions and physical growth were updated monthly. RESULTS: ARI incidence was 14 episodes per child/year among DCC infants with a median of 74 sick days, while among children at home, the ARI incidence was 6 episodes, and the median was 40 days. The incidence density ratio for DCC children was 2.33 (95% CI, 2.13-2.54); after adjusting for other covariates, the relative risk increased to 5.27 (95% CI, 3.54-7.83). CONCLUSIONS: Infants attending DCCs will suffer ARI more frequently than children cared for at home. We did not find seasonal variations in the incidence rates among DCC infants. The quality of care provided at these facilities should be analyzed in more depth for proposing measures to decrease ARI incidence.

[Design and applicability of a clinical guide for appropriate attention in acute respiratory infections]. / Diseño y aplicabilidad de una guía clínica para la atención apropiada en las infecciones respiratorias agudas.

Clinical guidelines provide continuing education and help physicians in the clinical decision-making process. Clinical guidelines to manage acute respiratory infections (ARI) were developed comprehensively from a perspective where prevention, diagnosis, treatment and the patient's education were considered. Methodology. The guideline development process was comprised of two stages: 1. The building stage consisted of several steps: definition of the problem, definition of the potential users of the guidelines, and the appropriate level of care; review of updated bibliographies, and validation using the Delphi technique. 2. The start-up stage consisted of evaluating the guidelines applicable to out-patient settings. Twenty family physicians participated, using the guidelines with 115 patients. Agreement between the family physicians' diagnosis and the criteria stated in the guidelines was tested using unweighted kappa. Differences in the use of the guidelines to manage ARI patients were tested by using the X2 test or the exact Fisher test. Results. Development of guidelines considered the patient's age group. Therefore, guidelines to manage patients under five years of age and to manage patients above this age were constructed. The application of the guidelines was increased from 40 to 60%. As a result, inappropriate prescribing of antibiotics and cough syrups decreased. Although the guidelines could be helpful in treating ARI, its efficacy and effectiveness remain to be tested.

Blood culture and respiratory syncytial virus identification in acute lower respiratory tract infection.

Even though the incidence of pneumonia in developed and developing countries is similar, the mortality is five times higher in developing countries. This study aimed to determine the prevalence of bacteremia in children with acute lower respiratory tract infection (LRTI) and relative contribution of respiratory syncytial virus (RSV). One hundred and one children under five years of age who attended a primary care level clinic with diagnosis of acute LRTI, were enrolled. Diagnosis and management of pneumonia were done according to the WHO guidelines. Two blood cultures were drawn at the time of admission. A nasopharyngeal sample was taken for detection of RSV by indirect immunofluorescence. Blood cultures were positive for pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus) in three patients. The detection for RSV was positive in 24 patients (23.7%). The clinical and radiographic presentations were not significantly different between patients with and without RSV (p > 0.05). RSV is a common cause of LRTI in children younger than five years old. Blood cultures are not commonly positive in outpatients with acute LRTI. The practice of obtaining blood cultures in primary and secondary care clinics is not useful to guide the treatment of patients with community-acquired pneumonia.

Streptococcus pneumoniae: low frequency of penicillin resistance and high resistance to trimethoprim-sulfamethoxazole in nasopharyngeal isolates from children in a rural area in Mexico.

Due to the changes in the frequency of penicillin-resistant strains of S. pneumoniae, it is necessary to perform surveillance studies of bacterial resistance. Isolates from the upper respiratory tract of asymptomatic children have been useful. There is no information about the difference between isolates from children with and without upper respiratory tract infection (URTI). The objective of the authors in this paper is to establish the prevalence of carrier-state, serotype and antimicrobial resistance of S. pneumoniae isolates from children with and without acute upper respiratory tract infection (URTI) in a rural area in Mexico. A cross-sectional comparative study was performed in Tlaxcala, Mexico. Children from one month 5 years of age were included. Nasopharyngeal swabs were obtained. Identification was done by international microbiology standards. Serotyping was done by the capsular Quellung test. The susceptibility testing was performed by the agar dilution method. Four-hundred and fifty patients were included. S. pneumoniae was isolated in 134 children (29.7%). Frequency of carriers was greater in patients with URTI (107/323) than without URTI (27/127) (33.1% vs. 21.1% p = 0.012, OR 1.84, IC 95% 1.1-3.08). The six most frequent serotypes were: 6B (16.4%); 19F (11.9%); 19A (6.7%); 14, 23F, and 35 (5.2% each), with no difference among the groups. Only 3% of the strains had high level resistance to penicillin, and 12.6% had intermediate resistance, and for ampicillin 4%, amoxicillin 4%, amoxicillin-clavulanate 4%, ceftriaxone 3%, cefotaxime 1.5%, erythromycin 6%, miocamycin 3%, chloramphenicol 4%, and vancomycin 0%. Trimethoprim-sulfamethoxazole resistance was very high (42%). In conclusion, colonization is higher in children with URTI. Five of the most frequent serotypes identified in this study were the same as those identified in patients with S. pneumoniae invasive diseases in Mexico City. In Tlaxcala, Mexico, beta-lactams could be the drug of choice for the treatment of S. pneumoniae lower respiratory tract infections. It is necessary to perform clinical assays to evaluate the efficacy of trimethoprim-sulfamethoxazole due to the high resistance in vitro.

Seroepidemiology of the hepatitis B and delta in the southeast of Chiapas, Mexico.

An area of high endemicity for hepatitis B and delta antigen was identified in the southern border of Mexico (Chiapas). The study included individuals from mexican communities and guatemalan refugee camps. 91.1% of the subjects were positive to anti-HBcAg antibodies. The frequency of asymptomatic carriers of HBsAg went from 4.2% in mexican communities to 17.3% in guatemalan refugee camps, the percentage was higher in households with six or more persons per room (14.0 per 100 individuals). The prevalence of e antigen in subjects positive to HBsAg was higher among guatemalan refugees (35.3%) than among mexicans (7.7%). A refugee camp, Benemerito de las Americas, showed 65.6% positives to anti-HBcAg antibodies and 39.0% asymptomatic HBsAg carriers, 41.7% of these were positive to HBeAg. Antidelta antibodies were present in 50 of 119 subjects positive to HBsAg. The mechanism of transmission was mainly horizontal since most of the infected children in each household corresponded to the oldest offspring. Our data were similar to those observed in the amazonian region of Brazil, Southeast Asia and tropical Africa.

Detection of furazolidone in human biological fluids by high performance liquid chromatography.

Furazolidone has normally been administered as a non-absorbable antimicrobial agent for use in gastrointestinal infections. However, in India and Mexico it has been used successfully for the treatment of typhoid fever. We measured concentrations of furazolidone by high performance liquid chromatography (HPLC) in several biological fluids, after a single oral dose (5 mg/kg). Six healthy adult volunteers and seven children with typhoid fever and ten children with purulent meningitis were studied. In adults the peak serum concentration was less than or equal to 0.84 mg/l and less than or equal to 4.78% of the ingested dose was excreted in the urine. In the children concentrations were similar to those found in volunteers. The cerebrospinal fluid/serum ratio ranged from 1.02 to 5.95 in the meningitis patients. HPLC is a rapid and sensitive method for the quantitation of furazolidone in biological fluids. The minimum detectable concentration was 0.05 mg/l, with a precision of 6% from peak area and an average recovery of 98%.

Son utiles los antimicrobianos de accion local en la diarrea prolongada con sobrecrecimiento bacteriano en liquido duodenal? / Are the local antimicrobials action useful in prolonged diarrhea with bacterial overgrowth in duodenal content?

Para evaluar la utilidad de dos antibioticos de accion local en ninos con diarrea prolongada y sobrecrecimiento bacteriano en liquido duodenal (SBLD) se estudiaron 22 pacientes que fueron divididos en tres grupos: ocho recibieron colimicina, seis furazolidona y ocho ningun antimicrobiano.Despues del tratamiento, se negativizaron seis cultivos duodenales con colimicina (75%), cuatro con furazolidona (66%) y siete sin antibiotico (87.5%) (p > 0.05), remitiendo la diarrea a los 4.0, 4.5 y 3.0 dias respectivamente (p > 0.05). No se detecto septicemia en los pacientes sin antimicrobiano, mientras que esta se presento en uno que recibio furazolidona y en dos con colimicina (p > 0.05). No encontramos utilidad en el tratamiento con furazolidona o colimicina y es probable que exista un mayor riesgo de complicaciones infecciosas. Se estudiaron ademas los posibles mecanismos de patogenicidad en las bacterias aisladas

Centelleogammagrama hepatobiliar para el diagnostico diferencial entre hepatitis neonatal y atresia de vias biliares. / Hepatobiliary scintigraphy for differential diagnosis between neonatal hepatitis and atresia of bile ducts

Se practico centelleogammagrafia hepatobiliar con 99m tecnesio parabutyliminodiacetico a 20 ninos con el diagnostico de hepatitis neonatal y siete con atresia de vias biliares. A todos se les administro fenobarbital y colesteramina durante los cinco dias previos al estudio. A los 27 pacientes se les practico el gammagrama en forma estatica y a 15 en forma dinamica computarizada. En los 20 ninos con hepatitis neonatal se demostro material radiactivo en el intestino delgado. El tiempo de aparicion de este fue menor a 5 horas en los pacientes con colestasis leve a moderada y mayor a 6 horas en aquellos con colestasis intensa. No se aprecio material radiactivo en intestino en ninguno de los ninos con atresia de vias biliares. El registro dinamico computarizado se correlaciono en todos los casos en los que se practico con el estudio estatico, pero no aporto una mayor ayuda diagnostica. Se considera que la gammagrafia es de mucha utilidad para el diagnostico diferencial de estas dos entidades