Guidelines for diagnosing and treating pulmonary infiltrates in children with acute leukaemia: impact of timely decisions.

AIM: Children with leukaemia are at increased risk of pulmonary complications, often with unspecific clinical data, delayed diagnosis and a high mortality rate. We evaluated the usefulness of diagnostic-therapeutic guidelines (DTG) in which specific times for decision making were incorporated. METHODS: Clinical charts of children with acute leukaemia and suspicion of pulmonary involvement were reviewed. Patients were allocated to group I if their diagnostic and therapeutic decisions were in accordance with the DTG, and to group II if not. RESULTS: Children from group I (n=32) and group II (n=28) did not differ with respect to age (9.3+/-0.5 years old, mean+/-SEM), gender, type, risk and stage of leukaemia, anaemia and neutropenia. Total length of hospital stay and hospitalization due to the pulmonary disease were shorter in group I than in group II (14.8+/-2.1 vs. 28.5+/-3.7 days, p=0.0016; and 10.8+/-1.0 vs. 18.4+/-1.8 days, p=0.0003, respectively). Two patients (6.3%) died due to the pulmonary pathology in group I, and nine (32.1%, p=0.016) in group II. CONCLUSIONS: Diagnostic-therapeutic guidelines that incorporate timely decisions constitute a useful algorithm to reduce the length of hospital stay and mortality in children with acute leukaemia and pulmonary infiltrates. A prospective study is needed to validate these results.

Epidemiologic Study of Pseudomonas aeruginosa in critical patients and reservoirs.

BACKGROUND: Pseudomonas aeruginosa is a common cause of nosocomial infections, particularly in intensive care units (ICUs). The aim of this study was to characterize P. aeruginosa clinical isolates by comparing antimicrobial susceptibility patterns with the presence of plasmids and to establish the clonal relatedness by pulsed-field gel electrophoresis (PFGE) typing. METHODS: The patients included those with isolation of P. aeruginosa hospitalized for more than 48 h in the ICU from April to May 1998. Environmental and staff cultures were obtained simultaneously. Minimal inhibitory concentrations, plasmid DNA profiles, and PFGE genomic patterns of enzyme restriction chromosomal DNA were compared. RESULTS: Sixty P. aeruginosa isolates were obtained from 197 clinical specimens, 178 environmental samples, and 47 hand cultures of personnel. Antimicrobial resistance was as follows: tobramycin 100%; ticarcillin, cefotaxime, ceftriaxone, ceftazidime, and gentamicin 80%; cefepime 60%; amikacin, ticarcillin/clavulanate, imipenem, and meropenem 40%; piperacillin and norfloxacin 20%; carbenicillin 12%, and ciprofloxacin 0%. Plasmids were detected in 11 isolates (18%). PFGE typing showed that 23 isolates belonged to a common clone (pattern A), identified from five patients, two nurses, and 10 environmental samples. Ten isolates were grouped in four clusters and 27 isolates had unrelated genomic patterns. There was no relationship among DNA genomic patterns, plasmid profiles, and susceptibility patterns. CONCLUSIONS: PFGE demonstrated the existence of a common clone in a critical care area. Reinforcement of infection control measures is needed to avoid horizontal transmission and severe infections.

[Congenital rubella syndrome in infants treated at a pediatrics hospital]. / Síndrome de rubéola congénita en lactantes atendidos en un hospital pediátrico.

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.

[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.

[Cryptosporidium parvum infection in malnourished and non malnourished children without diarrhea in a Mexican rural population]. / Infección por Cryptosporidium parvum en niños desnutridos y no desnutridos sin diarrea en una población rural mexicana.

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.

[Nosocomial infections. Experience at a third-level pediatric hospital]. / Infecciones nosocomiales. Experiencia en un hospital pediátrico de tercer nivel.

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.

[Case-control study of an outbreak of S. marcescens in a neonatal intensive care unit]. / Estudio de casos y controles en un brote de S. marcescens en una unidad neonatal de cuidados intensivos.

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.

Empirical antimicrobial therapy in pediatric patients with neutropenia and fever. Risk factors for treatment failure.

BACKGROUND: The use of combinations of antibiotics has been the cornerstone of therapy for febrile patients with cancer and severe neutropenia. Each empirical regimen should be selected according to the epidemiology and susceptibility patterns in each center. We describe here the experience with empirical antimicrobial treatments in pediatric patients with cancer, fever and severe neutropenia, and identify the risk factors associated with treatment failure. METHODS: This is a prospective study including 145 patients with cancer, and 171 episodes of neutropenia and fever. Blood cultures were taken before initiating empirical treatment: a) carbenicillin (400 mg/kg/day) plus amikacin (21 mg/kg/day) (Cb/ak), and b) ceftazidime (100 mg/kg/day), plus amikacin at the same dosage (Cz/ak). RESULTS: The overall response rate was 54.9% and 56.3% for Cb/ak and Cz/ak, respectively. Fifty-seven episodes (33.3%) were microbiologically documented, gram-positive isolated in 38% and gram-negative in 49%. Risk factors associated significantly with treatment failure were acute myelocytic leukemia (AML) (RR 2.59, CI 95% 1.42-4.7, p = 0.003); bacteriological identification (RR = 4.41, CI 95% 2.21-8.8, p < 0.001), and the presence of two or more sites of infection (RR = 2.89, CI 95% 1.03-8.11, p = 0.03). CONCLUSIONS: The rates of response are similar to the combinations used in the hospital (Cb/ak, Cz/ak). The risk factors associated with treatment failure were AML diagnosis, bacteriological identification, and the presence of two or more sites of infection.

A blood micro-culture system for the diagnosis of bacteremia in pediatric patients.

The aim of this study was to evaluate the utility of a volume-modified blood culture system to diagnose bacteremia in newborns and infants. A total of 793 paired blood cultures, obtained from 464 patients (173 newborns and 291 infants), were analyzed. Vacutainer tubes containing 18 ml supplemented peptone broth sodium-polyanethol-sulfonate were used as the gold standard, in comparison with a blood micro-culture system containing 1.8 ml of the broth. Prior to antibiotic treatment, 2.2 ml of blood was obtained from each patient; 0.2 ml was inoculated in a blood micro-culture tube and 2 ml in a routine tube. Sensitivity, specificity and predictive values were calculated. Microorganisms were isolated in 153 standard blood culture tubes and 151 blood micro-culture tubes. The sensitivity of the blood micro-culture system was 95%, specificity 99% and positive and negative predictive values 96% and 99% respectively. The sensitivity and specificity of blood micro-culture in neonates and infants is high. We recommend that this system be used for the diagnosis of bacteremia in newborns and infants in laboratories where manual systems are still in use.

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.

[Amikacin in single daily doses in children with fever]. / Amikacina en dosis única diaria en ninõs con fiebre.

A randomized clinical trial was performed in children with cancer, fever and neutropenia, to evaluate the efficacy of amikacin once daily versus thrice daily dosing plus carbenicillin in both groups. Fifty patients were included, 25 patients in group A who received amikacin once daily and 25 in group B who received amikacin thrice daily. No intergroup differences were observed, i.e., fever diminished in a median of 6 days (2-8 days) vs. 7 days (3-12 days) in groups A and B respectively (p = 0.37);clinical improvement was observed in a median of 6 days (3-10 days) vs 7 days (2-14 days) (p = 0.68). One patient in group A and two in B died. The peak levels of amikacin on the 7th day of treatment were 10-60 and 7-25 micrograms/mL in groups A and B respectively, and the serum creatinine levels were 0.3 - 0.7 for group A and 0.2 - 0.8 mg/dL for group B; none of the patients presented a creatinine above 40% of the basal value. Three patients of group A had amikacin levels higher than 40 micrograms/mL without increasing the creatinine levels; our observations do not suggest that toxicity is higher. We conclude that the administration of aminoglycoside once daily seems to be as effective as the traditional dosing.

[Kala-azar in Mexico: report of 2 cases]. / Kala-azar en México: informe de dos casos.

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.

[Disseminated histoplasmosis in pediatrics. Report of a case]. / Histoplasmosis diseminada en pediatría. Informe de un caso.

We report a case of a female infant, from Acapulco Guerrero, Mexico. She had been sick for 45 days, with diarrhea and general malaise, fever during the last 20 days; at physical examination she was pale, with abdominal distention and hepatosplenomegaly. She had leukopenia, thrombocytopenia and anemia. The microscopic findings in the bone marrow sample were intracytoplasmic and extracellular bodies. Both bone marrow and blood cultures were positive for Histoplasma capsulatum. Seventy three pediatric cases of diseminated histoplasmosis have been described in the medical literature since 1934 to 1988. It is know that only about 1% of the persons that become infected will develop a diseminated disease.