Etiología de sepsis neonatal y sensibilidad a los antibióticos en el Nuevo Hospital Civil de Guadalajara / Ethiology of neonatal sepsis and sensitivity to antibiotics in the New Civil Hospital of Guadalajara

Objetivo: Identificar las bacterias causantes de sepsis neonatal y sus patrones de sensibilidad a diversos antibióticos en el Nuevo Hospital Civil de Guadalajara. Material y métodos: El estudio se realizó en la unidad de cuidados intensivos neonatales de un hospital de segundo nivel de atención en guadalajara, Jalisco, México. Se analizaron 74 neonatos con sospecha clínica y/o paraclínica de sepsis, bajo un diseño prospectivo, transversal, observacional y comparativo. Se consideró como infectados a los neonatos que en dos hemocultivos tomados de sitios diferentes de venopunción, tuvieron el mismo aislamiento. Los antibiogramas se realizaron por el método de kirby-Bauer, con los puntos recomendados por la NCCLS. Resultados: Hubo 41 (55.4 por ciento) pacientes con hemocultivos positivos. De los aislamientos, 30 (73 por ciento) correspondieron a K. pneumoniae y 8 (19 por ciento) a S. epidermidis. Todas las cepas de K. pneumoniae fueron resistentes a ampicilina, pero 93 por ciento fueron sensibles a los aminoglucósidos y las cefalosporinas de tercera generación probados. Todas las cepas de estafilococos fueron sensibles a vancomicina y sólo dos fueron resistentes a dicloxacilina. Conclusiones: El 98 por ciento de las cepas de K. pneumoniae presentó el mismo patrón de sensibilidad a los antibióticos, lo que sugiere una transmisión horizontal intrahospitalaria. La gran mayoría de los aislamientos fueron sensibles a los antimicrobianos de uso común, por lo que sugerimos que el tratamiento empírico inicial debe incluir a aminoglucósidos como gentamicina o amikacina, asociados a dicloxacilina o en casos específicos vancomicina y dejar como alternativa el uso de cefalosporinas de tercera generación.

Explanation for false-positive urine cultures obtained by bag technique.

OBJECTIVE: To test whether a urine bag technique, previously shown in circumcised male infants 1 month to 1 year of age to yield no false-positive cultures, would give similar results in newborns (females and circumcised and uncircumcised males). DESIGN: Prospective study in which periurethral and urine specimens were obtained from healthy newborns. After the periurethral specimen was obtained, the perineum was washed and a urine bag applied. The urine bag was removed immediately after voiding and the urine was cultured. SETTING: Normal newborn nursery and pediatric hospital. SUBJECTS: Ninety-eight healthy full-term newborns (49 female and 49 male) admitted to the normal nursery during a 4-month period. MAIN RESULTS: Isolation of a pathogen from the bag urine reflected periurethral flora. In 20 (95%) of the 21 urine specimens from which a pathogen was isolated, the same pathogen was detected on the periurethra. Sixteen of the 21 urine cultures were falsely positive (> 10(4) colony-forming units of pathogen per milliliter). In 50 (98%) of the 52 urine samples that yielded no growth, the periurethral culture was also negative. In the remaining 25 urine samples in which nonpathogens were detected, the periurethra yielded nonpathogens or no growth. Thus, if a pathogen was isolated from a bag urine sample, the same pathogen was detected on the periurethra 95% of the time. Conversely, if the bag urine sample was negative for a pathogen, the periurethral culture was negative 100% of the time. The presence of a pathogen on the periurethra was more common in female than male neonates (16 of 49 vs four of 49; P = .004), and none of the 14 circumcised male neonates had a pathogen detected on their periurethra or in their urine. CONCLUSION: This study explains the finding of false-positive cultures with the bag technique. Pathogens detected in bag urine samples reflected pathogens on the periurethra. Until a bag collection technique that avoids contamination by periurethral flora can be developed, urethral catheterization and suprapubic aspiration remain the methods of choice for obtaining a urine specimen in female and uncircumcised male neonates.

Detección de marcadores parasitarios y virales en embarazadas adolescentes y sus recién nacidos de riesgo / Detection of parasitary and viral markers in pregnant adolescent women and their newborns in risk

Las embarazadas adolescentes constituirían por su condición etárea una población de alto riesgo de infección por agentes relevantes en el binomio madre-hijo. Se investigó en 139 embarazadas adolescentes, la prevalencia de anticuerpos anti Toxoplasma gondii, Trypanosoma cruzi, Virus hepatitis B (VHB), citomegalovirus (CMV), Virus rubéola (VR) y Virus de la Inmunodeficiencia humana (VIH), así como la presencia de marcadores de infección en sus recién nacidos (RN) de riesgo. Se utilizaron las técnicas de Sabin y Feldman, fijación del complemento, ELISA, hemoaglutinación indirecta y xenodiagnóstico. Se detectó 30.9 por ciento de seropositivas para T. gondii, siendo estas madres y sus RN IgM negativos. Se detectaron dos madres con Acs anti T. cruzi (1.4 por ciento) y uno de los RN presentaba parásitos circulantes. En relación al estudio virológico, se detectó un 93,5 por ciento de madres seropositivas para CMV siendo sus RN IgM negativos, un 90,6 por ciento de las adolescentes eran antirrubéola positivas y se detectó un caso de adolescentes positiva para VIH. Las prevalencias establecidas en este grupo de embarazadas, no son significativamente diferentes a las encontradas en la población general de embarazadas

Carriage of beta haemolytic streptococci (BHS) in pregnant women and acquisition by neonates.

Beta Haemolytic Streptococci(BHS) carriage rate in pregnant women during labour and its acquisition by their newborns just after birth was investigated in 60 mother baby pairs. The carriage rate of group B Streptococci (GBS) was 11.6%, acquisition rate by newborns of carrier and non-carrier mothers was 85.7% and 1.8% respectively. A total of 28.5% newborns were carrying GBS on all the skin sites and were heavily colonized and therefore, at higher risk of developing early onset of Streptococcal infections. Penicillin G and Ampicillin were most effective antibiotics against GBS.

Early infant feeding and micro-ecology of the gut.

Newborn infants are rapidly colonized by both aerobic and and anaerobic bacteria, initially with about 50% of each type. Several factors related both to the infant and its environment influence the composition of the intestinal microflora quantitatively as well as qualitatively. Major ecological disturbances are observed in newborn infants treated with antimicrobial agents. One way of minimizing the ecological disturbances, which may be seen in infants treated in neonatal intensive care units, is to provide them with fresh breast milk from their mothers and to use antimicrobial therapy only under strict clinical indications.

Sorrento studies of diet and fecal flora in the newborn.

The fecal flora of a breast-fed baby is very different from that of a bottle-fed baby. This paper reviews five previous studies, performed at this hospital concerning the effect of various dietary components (whey proteins, casein, lactoferrin, iron, nucleotides) on the fecal flora. The babies received either breast milk or one of the test formulas from birth. Fecal samples were examined by quantitative microbiological methods at 4 and 14 days and at various intervals thereafter. By 14 days differences in the fecal flora were established. Among breast-fed babies bifidobacteria, lactobacilli and staphylococci were predominant organisms, whereas in the formula-fed babies the predominant organisms were enterococci, coliforms, and Bacteroides. A whey-based formula without bovine lactoferrin, iron or nucleotides gave a flora a little closer to but still remote from the breast-fed one. Despite extensive modification of cow's milk in the manufacture of a modern infant formula, the fecal flora of bottle-fed babies remains substantially different from that of breast-fed babies.

Improved specificity of in vitro anti-HIV antibody production: implications for diagnosis and timing of transmission in infants born to HIV-seropositive mothers.

In vitro anti-HIV antibody production (IVAP), initially introduced as a method for diagnosis of human immunodeficiency virus type 1 (HIV-1) infection in infants, has been limited in its application because of poor specificity and sensitivity early in life. The aims of this study were to improve the specificity of the IVAP assay and to evaluate its sensitivity in conjunction with assays of HIV culture, polymerase chain reaction (PCR), and p24 antigen. To prevent false-positive reactions resulting from maternal serum-derived cytophilic anti-HIV IgG, additional preculture and washing steps for peripheral blood mononuclear cells (PBMCs) were introduced that resulted in dramatic improvement in specificity of IVAP. The sensitivity of the revised IVAP at age < 3 months in 20 infected infants was, however, only 25%; of 15 infected infants initially negative in IVAP, 13 became positive at a mean estimated age of 4.4 +/- 1.8 months. When correlated with virological assays, a failure to respond in IVAP at age < 1 month was often associated with negative virological identification, whereas a positive IVAP response at age < 3 months was always associated with positive results in all virological assays. Moreover, conversion from negative IVAP to positive responses occurred subsequent to, and not concurrently with, a positive virological identification of infected infants. The revised IVAP methodology renders this assay potentially useful as an additional tool not only for the diagnosis of HIV infection, but for estimating timing of maternal-infant HIV transmission as well.

Etiologías de la septicemia neonatal en una unidad de perinatología: informe de siete años / Neonatal septicemia etiology in a perinatology unit: seven years report

Se realizó un estudio para conocer la etiología de la infección sistémica neonatal durante el periodo de enero de 1986 a diciembre de 1992. Se estableció el diagnóstico de septicemia corroborada bacteriológicamente en 685 pacientes. Se observó un incremento de los microorganismos antiguamente considerados como comensales reportándose para Staphylococcus aureus una tasa que ha variado de 1.5/1000 a 6.5/1000 nacidos vivos; Staphylococcus epidermidis, se encontró una tasa de 2.3 a 10.2/1000 nacidos vivos; Candida sp se vio incrementada de 0.3/1000 a 1.3/1000. Otros microorganismos patógenos como Streptococcus del grupo B y D, así como Listeria monocytogenes, presentaron tasas similares a las de otras enterobacterias aisladas y consideradas en conjunto. De acuerdo al tiempo de presentación clínica en los casos de infección temprana (menos de 72 horas), se documentó Escherichia coli como el principal agente con 53 casos, seguido del género Streptococcus con 34 casos. En los casos de presentación tardía (mayor de 72 horas) predominaron S. aureus con 166 casos, seguido de S

Sistema inmune e inmunoterapia en el recién nacido I: El recién nacido como hospedero inmunocomprometido / Immune system and immunoteraphy in the newborn I newborn as a immunocompromises host

A pesar de grandes avences para el apoyo del recién nacido grave, incluyendo la introducción de surfacteante, nuevos y más potentes antibióticos, mejores ventiladores, etc., la mortalidad asociada a sepsis continua siendo muy alta. Esto puede ser debido a la inexperiencia e inmadurez del sistema inmunológico del recién nacido. En esta primera parte se resumen los aspectos de la inmunidad, no específica (PMN), específica (células B y T) y mixta (monocitos/macrófagos, células NK), que señalan al recién nacido como un hospedero inmunocomprometido. También se hacen algunas consideraciones con respecto a otras condiciones que hacen al neonato susceptible a infecciones

Independent variation and positive selection in env V1 and V2 domains within maternal-infant strains of human immunodeficiency virus type 1 in vivo.

Multiple targets for immune recognition and cellular tropism are localized to the V1 and V2 hypervariable regions in the amino portion of human immunodeficiency virus type 1 (HIV-1) gp120env. We have assessed genetic diversity in env V1 and V2 hypervariable domains in vivo within epidemiologically related strains of HIV-1. Our strategy was to analyze longitudinal samples from two seropositive mothers and multiple children infected by perinatal transmission. Although the V1 and V2 domains are closely linked in the HIV-1 genome, nucleotide sequences in V1 and in V2 evolved independently in maternal-infant viruses in vivo. A high proportion of the nucleotide substitutions would introduce amino acid diversity in V1 and in V2. A significant excess of nonsynonymous over synonymous substitutions was identified in HIV-1 env V1 and V2 peptides in the mothers and in two older children but was not generally apparent in HIV-1 sequences in infants. An excess of nonsynonymous over synonymous substitutions indicated that there is positive selection for independent genetic variation in the V1 and V2 domains in vivo. It is likely that there are host responses to complex determinants in the V1 or V2 hypervariable domain of HIV-1 gp120.

Anti-HIV 1 antibodies prevalence in parturients through newborn testing: results of the Italian anonymous serosurvey. The Italian Collaborative Study Group of HIV Prevalence in Newborns.

A prevalence assessment of HIV infection among parturients was performed in order to estimate the future incidence of pediatric AIDS cases and obtain data on the trend of the infection in Italy. Consecutive whole blood samples from newborns collected on filter paper from all regions of Italy (October-December 1990) for routine metabolic screenings, were anonymously examined for HIV-1 antibodies by an ELISA technique. Positive results were confirmed by Western blot. Among 97,658 blood samples tested, 121 (0.124%, 95% confidence interval Poisson distribution 0.103-0.148) were positive. A high prevalence of HIV infection (> 0.2%) was observed in four regions from North and Central Italy while, in some regions in the South, the seroprevalence was ten times lower. In the Lazio Region, namely in Rome, 5 inner-city hospitals with a particularly high prevalence of HIV infection were identified. Assuming that the prevalence of HIV infection observed in the population in this study may reflect the infection rate in the total population of childbearing women, we estimate that approximately 700 newborn babies were delivered from HIV-positive mothers in Italy during 1990. The identification of high prevalence areas could allow for the development of "targeted" testing programs to plan and provide adequate counselling and care of HIV-infected women and their infants.

[Colonization by Streptococcus group B in full term pregnancy and newborns in a community in Venezuela]. / Colonización por Streptococcus grupo B en embarazadas a término y recién nacidos en una comunidad de Venezuela.

BACKGROUND: The aim of this study was to define the incidence of cervico-vaginal colonization by group B Streptococcus (SGB) in full term pregnancy as well as vertical and horizontal transmission in newborns attended in two public hospitals in Valencia, Venezuela. METHODS: An study cervico-vaginal exudates from 171 full term pregnant women was performed together with general obstetric survey. Oropharyngeal and nasal exudate studies in 118 newborns of the mothers studied were carried out during the first 12 hours after birth as was a neonatologic survey. RESULTS: The global percentage of maternal colonization by SGB were 32.7% while in the NB it was 45.8%. Among the NB colonized by SGB 73.2% were considered to have acquired the bacteria from the mother (vertical) with no significant differences in the data found in the two hospitals. The rate of horizontal colonization of the newborns was 42.3% in one hospital and only 8% in the second. CONCLUSIONS: There were no significant statistical differences between the rate of cervico-vaginal colonization in women attended in two public hospitals in Venezuela. No differences were observed in the rate of vertical colonization of newborns but to the contrary, that of the horizontal (nosocomial) colonization was of 42.3% and 8% in the Charity and University Hospitals, respectively.

Crystal violet reactions of Staphylococcus aureus strains colonizing infants in the first six weeks.

Nasal colonization with Staphylococcus aureus occurred in 18% of babies leaving a maternity unit and had risen to 40% by 6 weeks after birth. S. aureus was first acquired by 34.5% of babies after discharge. Female infants were more likely to be colonized than males. Colonization was not significantly different between babies receiving standard postnatal care and those nursed on the Special Care Baby Unit. Crystal violet (CV) tests showed that purple-reacting isolates accounted for approximately 60% of strains, whether first detected at hospital discharge or subsequently acquired. Purple-reacting strains, once acquired, were significantly better able to persist than non purple-reacting strains and formed a cumulatively higher proportion of the strains isolated at 6 weeks after birth than at hospital discharge. CV purple-reactions were significantly associated with lysis by phages of groups III and I and non-purple-reactions were significantly associated with lysis by phages of group II and/or 94/96. Maternity units remain a significant route whereby strains of S. aureus with some characteristics associated with a hospital origin gain access to the community.

Acquisition of nonmaternal Enterobacteriaceae by infants delivered in hospitals.

To determine whether Escherichia coli strains that colonize the intestinal tract of newborn infants in hospitals are of maternal origin or come from the environment, plasmid profiles of E. coli strains isolated from the stools of infants were compared with those from the stools of their mothers. Twenty-nine mother-infant pairs were studied in three different hospitals. In only 4 of 29 pairs, plasmid profiles of E. coli or other Enterobacteriaceae were shared by infant and mother; vertical transmission seemed to be uncommon, unlike findings in previous reports. In one hospital, 8 of 10 infant fecal E. coli strains shared a single plasmid profile, strongly suggesting nosocomial acquisition. In another, 7 of 9 neonate strains also shared a unique profile, and additionally carried K1 capsular antigen, a known virulence factor. Two other infants from the latter nursery acquired a urinary tract infection with E. coli K1 carrying the same plasmid profile. This study indicates that nosocomial acquisition of hospital strains of E. coli by neonates may be common in some hospitals and that the clinical implications are potentially serious.

Colonization with coagulase-negative staphylococci in two neonatal units.

Episodes of septicaemia due to coagulase-negative staphylococci (CNS) were more frequent in a level III than in a level II neonatal unit in Stockholm, Sweden. Colonization with CNS during the first 2 weeks of life was investigated in 10 infants from each unit. As the use of antibiotics differed between the two units, the aim was to correlate colonization and antimicrobial resistance patterns to antibiotic usage. Antimicrobial susceptibility of CNS to isoxazolylpenicillins, co-trimoxazole, erythromycin, clindamycin, chloramphenicol and gentamicin was determined. Selected isolates were typed with restriction endonuclease analysis of plasmid DNA and of genomic DNA. Infants were frequently colonized with multiple strains and species of CNS, and transmission of strains from patient to patient occurred within the unit. Qualitative and quantitative differences in antibiotic use were not correlated with colonization. The prevalence of resistant isolates, mostly of Staphylococcus haemolyticus, was higher in the level II unit with lower use of antibiotics. Staphylococcus epidermidis, which is generally more virulent, prevailed in the level III unit, where there were more severely ill children and invasive procedures were more frequently performed.

[The effect of oral colonization by non-pathogenic E. coli on the immune response in neonates and possibilities of its use in the prevention of nosocomial infections in children at risk]. / Vliv perorálního osídlení nepatogenním kmenem E. coli na imunitní odpoved' u novorozencu a moznosti jeho vyuzití pro prevenci nozokomiálních nákaz u rizikových detí.

Oral colonization with the non-pathogenic strain of E. coli 083:K24:H31 stimulated in a significant way the local antibody formation in the gut, saliva and milk of mothers of the colonized infants. Early induction of SIgA formation is important in particular in infants who are not breastfed where it replaces partially the lacking immunoglobulin supplied in breast milk. In premature and risk infants colonization had a favourable effect on reduction of the number of infections, deaths in conjunction with infection, a reduced presence of pathogenic microflora in the alimentary tract and elsewhere. In carriers the strain replaced successfully pathogenic strains and assisted the restitution of the impaired intestinal microflora.

Quantification of human cytomegalovirus DNA using the polymerase chain reaction.

The important goal of developing quantitative assays for viral nucleic acids in clinical samples has been achieved for human cytomegalovirus (HCMV) by using a modified polymerase chain reaction (PCR). A control PCR target sequence was constructed by PCR mutagenesis to allow the post-amplification quantification of HCMV DNA. The control region was identical to a naturally occurring sequence within the glycoprotein B (gB) coding part of the virus genome, except that a unique restriction site, introduced by the aforementioned mutagenesis step, allowed post-amplification differentiation of control/non-control target amplified product. This technique was initially validated using known amounts of cloned control/non-control target DNA, and was found to be sufficiently sensitive to allow the quantification of a range of 10 to 10(6) genome equivalents of virus. The method was applied to urine samples of congenitally infected infants for which infectious virus titres were available. The results obtained demonstrated that the number of infectious virions determined by conventional cell culture represented a small proportion of the HCMV genome present in the samples, as assessed by the quantitative PCR methodology.

Further characterisation of human rotaviruses isolated from asymptomatically infected neonates in South Africa.

Stool specimens were collected from healthy neonates at Ga-Rankuwa Hospital in the winters of 1984 and 1986 and tested for the presence of rotavirus infection. Asymptomatic excretion was found to occur in 25% of the newborn babies analysed. Gel electrophoresis of the rotavirus RNA genome revealed that a genomically stable strain of rotavirus was endemic in the ward at the time intervals examined. Hybridisation analysis of the VP4 and VP7 rotavirus genes, which encode the outer capsid neutralization proteins of the virus, was conducted. These results showed the presence of a serotype 4 rotavirus strain with an M37-like VP4 gene allele, which remained conserved in the nursery over the time period examined. Partial nucleotide sequences were obtained for a variable region of the VP7 gene and for the hyperdivergent region of the VP4 gene from 8 of these viruses and showed that remarkable conservation of these regions in the genes of the viruses occurred over time.