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.

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.

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.

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.

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.

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]

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.

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.

[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]

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.

[Plasmid profile and toxicity of Klebsiella pneumoniae strains isolated at a neonatal department]

The authors tested the plasmid profile of 11 and the toxicity of 16 strains of K. pneumoniae isolated in a neonatal department. Based on examination of the plasmid profile it may be assumed that very probably a nosocomial spread of the strains was involved. This is suggested by the identical plasmid profile of all strains isolated in the environment and five strains isolated from neonates. On investigation of the enterotoxicity of culture filtrates of the investigated strains the authors did not reveal the presence of a thermolabile or thermostable enterotoxin. In the skin test on rabbits 93.8% of the tested samples were positive. Morphological changes on Vero cells after 48 hours action were produced by four culture filtrates. Only two strains caused haemolysis of agar with 6% sheep and rabbit blood after incubation at 37 degrees C. Another 14 strains caused lightening of the agar with rabbit blood after subsequent incubation at 4 degrees C.

[Ureaplasma urealyticum and Mycoplasma hominis: incidence and clinical significance of their isolation in the perinatal period]

In order to known the clinical significance of the colonization of the maternal genitalia and infant with genital mycoplasmas, we studied prospectively 219 pairs of mothers and newborns admitted for delivery to a general public hospital. U. urealyticum and M. hominis were isolated from 72 (32.9%) and 10 (4.6%) of the mothers, respectively. During the first 4 days of life. U. urealyticum and M. hominis were isolated from 23 (10.5%) and 1 (0.5%), of the newborn infants respectively. Maternal colonization by genital mycoplasmas was not associated with a longer duration of membrane rupture, nor with a shorter gestational age, nor with smaller neonatal weight and length. Neonatal colonization by U. urealyticum was not associated with shorter gestational age, nor with smaller birth weight and length, nor with the appearance of any disease during the first 3 months of life.

Separate isolation of Clostridium difficile spores and vegetative cells from the feces of newborn infants

A modified taurocholate-cefoxitin-cycloserine-fructose agar medium, pH 5.5, on which vegetative cells alone could grow, was newly devised for separate isolation of Clostridium difficile vegetative cells and spores from feces. The ratio of C. difficile-positive feces from healthy newborn infants younger than 10 days of the age was 30.8%, and 93.3% of feces from healthy infants older than 20 days were positive for C. difficile. C. difficile spores alone were detected in twenty-one samples (75%) of C. difficile-positive Twenty-eight specimens. Only 10.7% (3/28) C. difficile vegetative cells alone were detected. C. difficile spores alone were detected in one of nine healthy adults. These collective results offer potential explanations for high frequent isolations of C. difficile from newborn infants without occurrence of pseudomembranous colitis.

When do gut flora in the newborn produce 3-phenylpropionic acid? Implications for early diagnosis of medium-chain acyl-CoA dehydrogenase deficiency

Urinary excretion of 3-phenylpropionylglycine (PPG) is a diagnostic marker for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. PPG is derived from 3-phenylpropionic acid (PPA), a product of anaerobic bacterial metabolism in the gut. To determine when the infant gut was colonized with PPA-producing bacteria, we cultured stool in prereduced thioglycollate broth from 93 apparently healthy infants. We analyzed the products of bacterial metabolism by gas chromatography/mass spectrometry for the presence of PPA. Trend analysis demonstrated a significant difference (P less than 0.001) in PPA production between early and later infancy. PPA was not detected in 84% of media isolated from stool collected from infants younger than four months. For older infants, 67% of the samples were PPA-positive. Thus, because the normal gut is not sufficiently colonized with PPA-producing bacteria before three to four months of age, PPG analysis alone is not a sensitive marker for the early detection of MCAD deficiency. Using stable isotope dilution mass spectrometry, we measured PPG and n-hexanoylglycine (HG) excretion in two well newborns with MCAD deficiency. HG, believed to be an endogenous metabolite associated with MCAD deficiency, was consistently above normal in all urine samples.

Isolation of genital mycoplasmas from blood of febrile obstetrical-gynecologic patients and neonates

In a prospective study, 1156 blood specimens collected from hospitalized febrile obstetrical-gynecologic patients and neonates with suspected sepsis, were inoculated into a conventional biphasic culture medium, Castaneda S and cultures incubated aerobically. 15-24 h later the broth cultures were subcultured to specific media for detection of mycoplasmas. Genital mycoplasmas were isolated in 15 samples (taken from 8 women) and in 2 from 1 neonate. Mycoplasmas and members of the family Enterobacteriaceae were the most frequent significant bacteria isolated from adult specimens. Mycoplasma isolations were associated with either postpartum or postabortum febrile infections in women. Four of the neonates, whose mothers were infected, showed respiratory distress at birth; 1 of them had mycoplasmas in the blood. All febrile states in obstetrical or gynecological patients, and in neonates, should routinely lead to blood cultures for detection of mycoplasmas and ureaplasmas.

Candida strains from neonates in a special care baby unit

Carriage and acquisition of Candida spp and Candida albicans biotypes were studied among 163 neonates and 90 staff in a neonatal intensive care and surgical unit during a 17 week period. Twenty one neonates carried yeasts in the mouth, rectum or groin when first sampled, and a further 25 were positive later. C albicans accounted for 94.7% of 431 yeast isolates from neonates but only 67.4% of 43 isolates from staff. The first isolated C albicans biotype persisted in 13 babies monitored longitudinally. Simultaneous colonisation with two Candida spp was found in 2/46 neonates and 5/33 staff. The prevalence of candida was significantly higher among babies of gestational age less than 28 weeks (65%) than those of higher gestational age (26%). Oral and/or crural candida infection was observed in 14 of the babies but none developed deep seated candidosis. Routine antifungal prophylaxis did not affect the frequency of yeasts among the neonates.

Acute phase reactants in neonatal bacterial infection

The C-reactive protein (CRP) level was evaluated in 142 infants requiring investigation for suspected infection. After excluding two neonates because of incomplete data, there remained 140 neonates, of whom 16 had septicemia. Fifteen of 16 had increased CRP levels. The CRP value was not elevated in any baby (n = 5) who had positive blood cultures for Staphylococcus epidermidis, all of whom had an uneventful clinical course. The CRP level was elevated in all six babies with meconium-aspiration syndrome, but was normal in five infants whose viral cultures were positive. Ninety-nine percent of uninfected babies had normal CRP values. Overall, CRP was a valuable test for diagnostic confirmation of bacterial infection. Elevated CRP level was always accompanied by at least one abnormality in the other tests performed. Although the study was not intended to predict clinical onset of bacterial disease, our results suggest that the CRP level, because of a high negative predictive value, may be useful in ruling out bacterial infection.

[Microbial colonization and succession in the large intestine of newborn infants during their stay with mothers at the maternity hospital]

Formation of microflora in the large intestine of 5-day old infants was studied in one of the Moscow maternity homes. The up-to-date procedures for isolation and identification of aerobic and anaerobic organisms were used in the study and the findings were processed on a computer. In the newborns of the maternity home of the "mother-infant" type there was observed colonization of the large intestine with aerobic and anaerobic organisms. A wave-like dynamics in the formation of the symbiotic microflora was revealed. It reflected the phenomenon of the microbial succession in the infants. The attempts to detect microbial interference between the species colonizing the large intestine showed that it was extremely rare in the 5-day old infants. This was likely the reason of the low intestine resistance to the colonization in the newborns which in its turn defined the frequent colonization of the intestine mucosa with S. aureus and the organisms of the Klebsiella, Enterobacter and Citrobacter group.

[Value and limits of research on Mycoplasma hominis and Ureaplasma urealyticum in the gastric fluid of newborn infants]

Mycoplasma hominis and Ureaplasma urealyticum were cultured and counted in the gastric fluid of 153 neonates divided into three groups: 28 preterm neonates managed in an intensive care unit (Group I); 83 full term neonates with suspected infection (Group II); and 42 full term neonates with no evidence of infection (Group III). The colonization rate (17.85%) in the intensive care unit group was not significantly different from the rates seen in the two other groups. These results do not militate against the pathogenic role of the two organisms studied but rather suggest a contributory role of other factors.

[Microbial colonization and succession on the faucial mucosa in newborn infants rooming in with their mothers in a maternity hospital]

The formation of microflora on the laryngeal mucosa in newborn infants during the first 5 days of their life was studied in one of the maternity hospitals of Moscow. In this work modern methods of the isolation and identification of aerobic and anaerobic microorganisms were used, and the results thus obtained were computer-processed. In the maternity hospital of the "mother-child" type the microbial colonization of the laryngeal mucosa by normal and opportunistic microorganisms was noted in newborn infants. A wave-like course of the formation of laryngeal microflora, indicative of microbial succession occurring in the child, was revealed. The attempt to establish the cases of microbial interference between the species colonizing the laryngeal mucosa revealed that it was very rarely observed in 5-day-old newborns. This feature was seemingly the cause of low resistance of the larynx to colonization in newborn infants, which determined frequent colonization of their laryngeal mucosa with Staphylococcus aureus and Klebsiella.

Bacteriological nasal flora in newborns indicating health and/or development of infection

During delivery, a fetus otherwise sterile during the intrauterine life, comes in contact with bacterial flora of the mother's birth canal, and then also with the ward personnel's skin and respiratory system flora. Due to the absence of competitive bacteriological flora, the nasal cavity is gradually colonized by microorganisms, especially those with a capacity of adhesion to epithelial cells of respiratory nasal mucosa. Bacteriological flora of the newborn's nasal flora was observed on days 1 and 3 postpartum, in an attempt to determine whether a finding of pathogenic bacterial flora in newborn's nasal mucosa indicates a localized infection only or points to the possible development of generalized infection. Bacteriological nasal flora was monitored in infants born by spontaneous delivery and in those born by cesarean section. In mothers of infants born by spontaneous delivery, bacteriological flora from the cervix uteri was investigated. Results of the study performed by usual methods revealed Escherichia coli and Staphylococcus aureus to prevail in the pathogenic flora. Gram-negative microorganisms were found to be good indicators of local infection of newborn's nasal mucosa, regardless of the absence of clinical symptoms.

Micromethod for PMN function studies in neonates

Polymorphonuclear neutrophils play an important role in host defense mechanism. To assess PMN function in neonate a micromethod using only a few drops of blood was standardised. PMN adherent to coverslip were incubated with bacteria and using a differential staining with Acridine Orange (AO) phagocytic and bactericidal capacity were estimated.

[Relation between isolation of bacteriophages from Clostridium difficile and cytotoxicity of the strains]

We studied the possible relationship between the presence of bacteriophages and cytotoxicity of Clostridium difficile strains from multiple origin. A total of 143 strains were studied, 38.46% showed lysogenic activity to at least one of control strains and 85.3% produces cytopathic effects on McCoy cells, that were neutralized by C. sordellii antitoxin. All bacteriophages seen on electron microscopy showed similar shape and size (hexagonal head shape and flexible tail ended in a basal plate). According to our results, a significant relationship between those two factors seems not to exist.

Bacterial interactions in the intestine of the newborn delivered by cesarean section

The purpose of this study was to clarify the role of the intestinal anaerobic bacteria colonizing the intestine of the newborn delivered by cesarean section. Control of the intestinal microecology is dependent on many factors including intestinal peristalsis, the intraluminal environment, and microbial interactions, that deter the overgrowth of pathogens populations. Numerous factors help achieve this normal balance. The effect of feeding seems to induce bacteriological changes.

Spread of Klebsiella in a neonatal ward

The colonization of infants with Klebsiella pneumoniae was prospectively studied. Samples were taken from nose, throat, umbilicus and rectum on the day of arrival and thereafter once a week. Phage typing was performed the first time K. pneumoniae was found at any of these sites. Settle plates were exposed in the incubators and in the patient rooms 5 h/day. The study lasted for 32 weeks. The first 15 weeks was a control period with no information to the staff, the following 4 weeks was a period of intervention and education and the last 13 weeks was a second control period. In all, 603 infants were investigated. The number of infants nursed per week and severity of their disease was comparable in the 3 periods. The colonization rates were 65, 34 and 58%, respectively. The acquisition of new strains was 1.4 per infant in the first and last periods, but only 0.4 in the period of intervention. Thus, colonization rates decreased only during the period of continuous education in hygiene.

Factors influencing the presence of faecal lactobacilli in early infancy

The faecal flora of 46 preterm infants and 52 born at full term was studied at 10 days of age; 46 born at full term and 37 preterm infants were also studied at 30 days. Viable counts of coliforms, lactobacilli, and bifidobacteria were made; gas liquid chromatography was used to identify the anaerobes. Lactobacilli, but not bifidobacteria, were found in high counts in the stools of most of the infants born at full term by 30 days of age. The mode of delivery, but not the method of feeding, had a significant influence on early colonisation. A selective deficiency of lactobacilli compared with coliform organisms was found in preterm infants. Previous treatment with antibiotics and being nursed in an incubator were also significantly associated with a lower rate of early colonisation with lactobacilli. Our findings indicate that lactobacilli may be an important part of the normal stool flora in early infancy, and that modern methods of neonatal care are associated with delayed or deficient colonisation.

Natural transmission of group B Streptococcus during delivery

This is a study of group B Streptococcus during labor of 121 patients in whom group B Streptococcus was isolated in the vagina and/or rectum before delivery. The intrapartum vaginal culture was positive in 55.2% of the antepartum carriers (32/58). When the vaginal culture during delivery was positive, the group B Streptococcus was isolated in the amniotic fluid 2 h after the rupture of membranes in 81% of the cases. The newborns of antepartum carriers, when the labor developed naturally, were colonized by group B Streptococcus in 69.2% of cases when the intrapartum vaginal and/or amniotic fluid cultures were positive (9/13), while only 5.6% of the newborns of antepartum carriers but with negative cultures during delivery were colonized by group B Streptococcus (1/18). The most frequent positive neonatal culture was in the umbilicus (83.3%) followed by the external ear (62.5%).

Modulation of Clostridium perfringens intestinal colonization in infants delivered by caesarean section

The colonization by Clostridium perfringens was investigated in 19 infants delivered by caesarean section during the two first weeks of life. The pattern of C. perfringens colonization depended upon the feeding. Breast feeding led to the repression of C. perfringens, whereas bottle feeding allowed its maintenance. On the contrary, Bifidobacterium bifidum growth was favoured by breast feeding. However, in one breast-fed infant, B. bifidum was never isolated and C. perfringens decreased. Breast feeding was able to directly modulate C. perfringens numbers. In fact, B. bifidum also had an effect, as demonstrated by the lower mean counts of C. perfringens, in bottle-fed infants carrying the bifidobacteria flora (p = 0.05). None of the bifidobacteria investigated in this study led to the same decrease.

A study of microbial flora of conjunctival sac in newborns

During the period from July to August 1987, the microbial flora in conjunctival sac of 93 newborns (186 eyes: normal vaginal delivery) and 19 newborns (38 eyes: cesarean section delivery) in nursery of Ewha Womans University Hospital were investigated for isolation and identification of bacteria on delivery day and on two days after birth. The results of the investigation are as follows: 1. Of 186 eyes (normal vaginal delivery), bacterial growth of one species was shown in 40 eyes (21.5%) on delivery day and in 64 eyes (34.4%) on two days after birth. Bacterial growth of two species shown in 10 eyes (5.4%) on delivery day and in 10 eyes (5.4%) on two days after birth. 2. Of 38 eyes (cesarean section delivery), bacterial growth of one species was shown in 2 eyes (5.3%) on delivery day and in 20 eyes (52.6%) on two days after birth. Bacterial growth of two species was shown 2 eyes (5.3%) on two days after birth. 3. Several kinds of bacterial species were isolated in normal vaginal delivery and cesarean section delivery. Staphylococcus epidermidis, Escherichia coli, Staphylococcus aureus were isolated.

Ureaplasma urealyticum pneumonia: experimental production and demonstration of age-related susceptibility

Two different strains of Ureaplasma urealyticum isolated in pure culture from the lungs of newborn human infants were shown to produce an acute, self-limiting, interstitial pneumonia in newborn C3H/HeN and C57BL/6 mice that were free of other respiratory pathogens. Lesion severity peaked 3 to 6 days following intranasal inoculation of ureaplasmas and was resolved by 12 days. Rhinitis and otitis also occurred but did so less frequently than pneumonia. Organisms were localized within the alveoli in areas of inflammation. In comparison with newborn mice, 14-day-old mice were less susceptible to either colonization or disease.

Detection of rubella virus in fetal and placental tissues and in the throats of neonates after serologically confirmed rubella in pregnancy

From 35 therapeutic abortions performed because rubella had occurred at 2-19 weeks of pregnancy, 120 fetal organs, 12 specimens of mixed products of conception, and 15 placentae were tested for rubella virus. Virus was isolated from 10 out of 11 fetuses (91 per cent) from women infected at 2-8 weeks, from 5 out of 8 (63 per cent) infected at 9-10 weeks, and from 2 out of 16 (13 per cent) infected at 11-19 weeks. Hybridization tests for viral RNA on 39 fetal organs from eight cases revealed infection in four additional fetuses. Virus was isolated from only 3 out of 15 aborted placentae, but hybridization tests on six placentae revealed infection in three additional specimens. Hybridization was superior to virus isolation for detecting rubella infection in products of conception and is therefore potentially the better method for examining chorionic villus biopsies. Rubella virus was isolated from the throats of 4 out of 9 infants (44 per cent) infected during the first 12 weeks of gestation, but from none of 13 infected after 17 weeks. Infants in the latter group are unlikely to infect susceptible contacts.

Screening for enteropathogenic Escherichia coli

In an attempt to identify the prevalence of enteropathogenic Escherichia coli (EPEC) carriage and to minimize the chances of admitting a baby to the neonatal wards with unsuspected EPEC infection, 27,174 maternity patients admitted in labour and 4049 neonates admitted to the Special Care Baby Unit (SCBU) were screened for intestinal carriage of common EPEC serotypes. Two hundred and sixty-five (1%) maternity patients were positive, of whom 8 (3%) had diarrhoea. Of the babies born to these mothers, 10 (3.8%) were infected with EPEC and in each the serotype was the same as the mother's. Nine neonates (0.2%) admitted to the SCBU were also found to be infected with EPEC. Seven of the 19 babies (37%) had diarrhoea. Symptomatic mothers or babies were nursed in isolation. During the 8 year period under study no incidents of cross-infection with EPEC occurred.

Epidemiology of Clostridium difficile colonization in newborns: results using a bacteriophage and bacteriocin typing system

We used a typing system based on bacteriophage and bacteriocin susceptibility to study the epidemiology of Clostridium difficile colonization of newborn infants. C. difficile was found in the stools of 30 (16.0%) of 187 infants who were screened. Increased length of stay in the nursery (P less than .001) and delivery by cesarian section (P less than .001) were associated with higher rates of colonization. The isolates initially detected from the environment and the infants were strain B1811-1700. Strain B1537/Cld7 became the predominant isolate obtained from the infants; positive cultures were also obtained from the environment and the hands of personnel who worked in the nursery and had strain B1537/Cld7. Our results suggest that the infants acquired C. difficile through transfer from the hands of hospital staff.

Perinatal transmission of hepatitis B virus-associated hepatitis D virus

Sera from 185 HBsAg carrier, pregnant Saudi women were tested for HBeAg, antibody to HBeAg (anti-HBe) and for antibody to hepatitis D virus (anti-HDV); 9.7% of the carrier mothers were anti-HDV-positive and the majority of them (94.4%) were anti-HBe-positive. Follow-up of 17 infants of anti-HDV-positive carrier mothers until about 7 months of age showed no evidence of perinatal transmission of HDV. Age-specific prevalence of anti-HDV in 280 Saudi carriers showed that infection with HDV is infrequent in infants and is mainly acquired during the second and third decades of life, which suggests that transmission of HDV is predominantly horizontal.