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Biomedical subjects

L K Pickering

Publications and source records attributed to L K Pickering.

At least 19 recordsLinked to original sources
PubMed1992

Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants.

To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.

Animals↗
PubMed1992

Outbreaks of human enteric adenovirus types 40 and 41 in Houston day care centers.

OBJECTIVE: Human enteric adenovirus (EAd) types 40 and 41 cause diarrhea in young children, but little is known about their association with outbreaks of diarrhea in the child care setting. This study evaluated EAd as a cause of outbreaks of diarrhea among infants and toddlers in day care centers. DESIGN: Stool specimens were collected weekly regardless of symptoms during four periods from January 1986 to April 1991, from children 6 to 24 months of age enrolled in prospective studies of diarrhea in day care centers. All diarrhea stool specimens were tested for bacterial enteropathogens, rotavirus, and Giardia lamblia. A total of 131 outbreaks occurred during the study. No etiologic agent was identified in 77 outbreaks. Stool specimens from 75 of these 77 outbreaks and from another 21 outbreaks of diarrhea with a known cause were evaluated for EAd with a monoclonal antibody-based enzyme immunoassay. RESULTS: A total of 4402 stool specimens from 613 children from these 96 outbreaks was tested for EAd. The virus was detected in specimens collected during 10 outbreaks, 3 of which occurred in 1986, 3 in 1988, 1 in 1989, 1 in 1990, and 2 in 1991. Of 249 children, 94 (38%) in these 10 EAd outbreaks were infected with EAd. In 51 children (54%) the infection was symptomatic and in 43 (46%) it was asymptomatic. Outbreaks lasted 7 to 44 days (mean 24.5 days). Duration of EAd excretion ranged from 1 to 14 days (mean 3.9 days), with excretion occurring from 7 days (mean 2.6) before diarrhea began to 11 days (mean 5.3 days) after diarrhea stopped. CONCLUSION: Enteric adenovirus types 40 and 41 are an important cause of outbreaks of diarrhea among children attending day care centers, often involve children in more than one room, and frequently produce asymptomatic infection.

Adenovirus Infections, Human↗
PubMed1992

Trimethoprim-resistant Escherichia coli in households of children attending day care centers.

Children in day care centers are frequently colonized with trimethoprim-resistant Escherichia coli. The frequency of transmission to family members was studied. Colonization with trimethoprim-resistant E. coli was detected in 13 (57%) of 23 day care center children. Among the 50 (98%) of 51 household members tested, colonization was detected in 13 (26%), representing 12 (52%) of 23 households tested. Households of colonized center children had significantly more colonized members than did households of noncolonized children (odds ratio, 13.3; 95% confidence interval, 1.3-172.6; P = .01). There was a trend toward higher prevalence of colonization in mothers (35%) and siblings (30%) than in fathers (12%). The same plasmid profiles of trimethoprim-resistant E. coli from center children were found among 8 (67%) of 12 colonized households. There was no association between antibiotic use and fecal colonization with trimethoprim-resistant E. coli. Thus, transmission of trimethoprim-resistant E. coli among children within day care centers and from center children to household members is common.

Carrier State↗
PubMed1992

Intermediate resistance of Streptococcus pneumoniae to penicillin in children in day-care centers.

This study was performed to determine the prevalence, serotypes and antibiotic susceptibility patterns of penicillin-resistant Streptococcus pneumoniae in children younger than 3 years of age in day-care centers in Houston, TX. Nasopharyngeal cultures were obtained on two occasions, in March and May, 1989, from 140 children in 4 day-care centers. All penicillin-resistant S. pneumoniae organisms isolated in this study had minimum inhibitory concentrations to penicillin of between 0.1 and 0.5 microgram/ml and were thus intermediately resistant. No highly resistant S. pneumoniae (minimum inhibitory concentration > or = 1.0 microgram/ml) was isolated in this study. Nasal carriage of S. pneumoniae occurred in 39% of children; carriage of intermediately resistant S. pneumoniae occurred in 4% of children. Of the 39% of children who carried S. pneumoniae, 11% carried intermediately resistant strains. In one day-care center with a prior history of intermediately resistant S. pneumoniae (Center 1), the prevalence of intermediate penicillin resistance was significantly (P = 0.047) higher than in the other three centers. Among children surveyed twice 15% of Center 1 children carried an intermediately penicillin-resistant strain at least once, whereas in the other centers 3% of children carried an intermediately resistant strain at least once. Sixty-two percent of intermediately penicillin-resistant strains were resistant to multiple antibiotics and all were serotype 14. Intermediately penicillin-resistant S. pneumoniae isolates were prevalent among young children in day-care centers in Houston and may persist in some day-care centers and become endemic.

Child Day Care Centers↗
PubMed1992

Identification by DNA sequence analysis of a new plasmid-encoded trimethoprim resistance gene in fecal Escherichia coli isolates from children in day-care centers.

In our ongoing studies of trimethoprim resistance (Tmpr) in day-care centers (DCC), we have shown a high rate of fecal colonization with Tmpr Escherichia coli and, using total plasmid content analysis, have shown that this is due to a diversity of strains. In the present study, we analyzed 367 highly Tmpr (MIC, greater than or equal to 2,000 micrograms/ml) isolates of E. coli from 72 children over a 5-month period and found at least 83 distinct plasmid patterns, indicating that at least 83 strains were involved. Several strains were particularly common in a given DCC, including one found in 61% of children with Tmpr E. coli; these common strains usually persisted within a DCC for several months. Colony lysates were hybridized with gene probes for dihydrofolate reductases (DHFR) types I, II, III, V, and VII; 21% hybridized under stringent conditions, and all of these were with type I (17%) or type V (4%) probes. Tmpr was cloned from a probe-negative Tmpr transconjugant, and an intragenic probe was prepared from this clone. Approximately 21% of the Tmpr E. coli strains (76 isolates) in the DCC were found to have this new gene, 74 of which were in one DCC. The DNA sequence of this gene was determined, and the predicted amino acid sequence was shown to have between 32% and 39% identity with the amino acid sequences for types I, III, V, VI, and VII and the partial sequence of type IV and approximately 26% identity with types IX and X DHFR. This confirms the uniqueness of this gene, which has tentatively been named dhfrxii, and its translation product, DHFR type XII.

Amino Acid Sequence↗
PubMed1992

Characterization of serum antibody responses to natural rotavirus infections in children by VP7-specific epitope-blocking assays.

Knowledge of the immune response to rotavirus is crucial for vaccine development. We compared an epitope-blocking assay (EBA) that uses VP7-specific monoclonal antibodies with neutralization assays (NAs) with polyclonal antisera for detecting serum antibody responses after natural rotavirus infection in children. Twenty-six serum pairs from children living in an orphanage with and without symptoms during two rotavirus outbreaks were evaluated for VP7 type 1-, 2-, 3-, and 4-specific antibody responses. In the first outbreak, which was caused by a VP7 type 3 strain, homotypic antibody responses were detected in 11 of 11 symptomatic children by NA and in 10 of 11 symptomatic children by EBA. Heterotypic antibody responses were detected more frequently (12 of 15 children) by NA than by EBA, and the heterotypic epitope-blocking antibody responses occurred in children older than 14 months of age. Antibody responses in asymptomatic children were more commonly detected by EBA than by NA. EBA results from the sera of children in the second outbreak indicated that it was caused by VP7 type 4, whereas NA results suggested it was caused by VP7 type 3. Our results confirm that EBA is a sensitive and specific method for determining VP7 type-specific immune responses after natural rotavirus infections.

Antibodies, Viral↗
PubMed1992

A comparison of herpes simplex virus specific antibodies found in human milk and serum.

It is not known if milk antibody protects infants from herpes simplex virus (HSV) infection. As a first step to test this hypothesis, anti-HSV antibodies were studied in human milk. Paired serum and milk samples were analyzed for anti-HSV antibodies by ELISA, Western blot analysis (WBA), neutralization (NT) plaque assay, and antibody-dependent cellular cytotoxicity (ADCC) assay. Nineteen of the 20 serum samples showed anti-HSV activity by ELISA and ADCC, and 18 showed activity by WBA and NT. We found a significant association between the immunoassays for detection of anti-HSV antibodies in sera. Fewer of the human milk samples showed anti-HSV activity; only one milk sample was positive by ELISA and one by NT assay, four by ADCC and 12 by WBA. The milk sample from the seronegative donor was also negative. We found a poor association of antibody titers in human milk and serum antibody titers using ELISA, NT, and ADCC assays. There was a significant (p = 0.022) association between serum and milk results using WBA. Among the four assays, WBA was the most sensitive for antibody detection. It will be used in an on-going prospective study to determine the role of anti-HSV antibody in the protection against HSV infections in infants.

Antibodies, Viral↗
PubMed1992

Impact of child day care on infectious diseases in adults.

The authors review diseases that occur in day care centers and their impact on day care providers and parents. Acute infections of the gastrointestinal and respiratory tracts are the most commonly transmitted illnesses from children in day care centers to adults. The most important infections acquired by adults are those with the potential for significant clinical morbidity, such as hepatitis A, or those that generate concern, such as cytomegalovirus and parvovirus B19, because of their potential to produce congenital infections in pregnant women.

Adult↗
PubMed1992

Infectious diseases and child day care.

It is estimated that more than 5.3 million children attend out-of-home child day care in the United States. This includes 2.1 million children who attend approximately 63,000 licensed child day-care centers. An additional 500,000 children receive care in 105,000 regulated day-care homes. Since the total regulated child care slots available in centers and homes are only 2.6 million, some 2.7 million additional children are likely attending unregulated family day-care homes. As a result infants and preschool children are intermingled in child care facilities that often lack adequate toilet and hand-washing facilities and are frequently staffed by individuals with little or no training in the area of infection control. Placing children in out-of-home care should not compromise their health and that of the community. The risk of infection can be lessened by teaching hygiene, supervising unregulated day-care facilities and regular antibiotic use so that bacterial resistance may be prevented.

Anti-Bacterial Agents↗
PubMed1991

The effect of diaper type and overclothing on fecal contamination in day-care centers.

Fecal coliform contamination of environmental surfaces and hands in the day-care center is common. This study evaluated the effect of two diaper types on fecal contamination. Ten rooms in four day-care centers containing 141 children were studied in a prospective, randomized, crossover study. A total of 2946 samples were cultured during the 9-week study. Fecal coliforms were isolated from 307 inanimate objects (15%), 73 toy balls (46%), and 131 hands (17%). The number of contaminated inanimate objects was significantly less in rooms where paper diapers were worn when compared with that in rooms where double cloth diapers with plastic overpants were worn and in rooms where clothes were worn over diapers. Inanimate object cultures had more contamination in rooms in which diarrhea had occurred. Containment of feces by overclothes and diaper type may be important in decreasing transmission of enteric pathogens in day-care environments.

Child Day Care Centers↗
PubMed1991

Environmental contamination in child day-care centers.

Enteropathogens associated with outbreaks of diarrhea in day-care centers are spread by the fecal-oral route through contaminated hands or environmental objects. This prospective study was undertaken to determine the prevalence of fecal coliform contamination in day care. Ten rooms in six centers housing 121 children less than 2 years of age were studied for 13 weeks (February to May 1988). Inanimate objects (n = 1,275), toy balls (n = 724), and hands (n = 954) were cultured 1-3 times per week. Fecal coliform contamination was common and was greater (p less than 0.05) for objects, toy balls, and hands of children in toddler compared with infant rooms. In five rooms in which clothes were worn over diapers, there was a significantly lower prevalence of fecal coliform contamination of toy balls (p less than 0.005), inanimate objects (p less than 0.05), and hands (p less than 0.001) when compared with rooms in which overclothes were not worn. Occurrence of diarrhea was significantly associated with increased contamination of hands (p = 0.001). Stool and environmental isolates from individual rooms had the same plasmid patterns, which were unique to each center. In summary, fecal coliform contamination of environmental objects and hands of children and caregivers in day-care centers is common; toy balls can serve as sentinels of contamination; fecal coliform contamination can be significantly decreased by use of overclothes; and Escherichia coli strains from stool showed the same plasmid patterns.

Child Day Care Centers↗
PubMed1991

Therapy for acute infectious diarrhea in children.

This article reviews current recommendations of therapy with antidiarrheal compounds and antimicrobial agents for acute infectious diarrhea in children. In most infants and children with acute infectious diarrhea, treatment with antidiarrheal compounds is not indicated. Many of these compounds interfere with identification of enteropathogens in stool specimens, and the antimotility class has an overdose potential. Antimicrobial therapy is given to reduce symptoms and to prevent the spread of infection by decreasing fecal shedding of organisms. Although effective therapy is not available for patients with enteric viruses, Cryptosporidium, and Microsporidium, therapy is useful for children with amebiasis, antimicrobial-associated colitis, cholera, giardiasis, various forms of Escherichia coli diarrhea and Salmonella disease, isosporiasis, shigellosis, and strongyloidiasis. For several other conditions, antimicrobial therapy is of questionable benefit (infection with Campylobacter jejuni or Yersinia enterocolitica, intestinal salmonellosis and enterohemorrhagic E. coli infection). Compounds such as the fluoroquinolones, which are effective in the treatment of acute infectious diarrhea in adults, are not approved for use in children because of potential side effects. Many bacterial, viral, and parasitic organisms cause acute infectious diarrhea; appropriate antimicrobial therapy requires the accurate, rapid identification of the offending enteropathogen. In children with an underlying illness such as acquired immunodeficiency syndrome, manifestations may be prolonged, severe, and recurrent despite appropriate therapy.

Acute Disease↗
PubMed1991

Diarrhea in children newly enrolled in day-care centers in Houston.

Diarrhea is a common illness among children in day-care centers (DCC). We hypothesized that the incidence of diarrhea was greater among children in their first 1 or 2 months after enrollment in a DCC than in any subsequent period in day care. We followed 442 children younger than 2 years of age enrolled in 13 randomly selected DCCs for the occurrence of diarrhea during a 14 1/2-month period. Parents completed standardized baseline questionnaires and research nurses visited the DCC twice weekly to record the occurrence of diarrhea and to collect stool specimens. Incidence rates, rate ratios, chi square statistics and 95% confidence intervals were calculated for crude and stratified analyses. The diarrheal incidence rate of 4.4 cases/child-year in the first 4 weeks in the centers was significantly (rate ratio, 1.6; confidence interval, 1.3 to 2.1; P less than 0.01) higher than the 2.7 cases/child-year incidence rate of diarrhea in subsequent weeks. The effects of gender, ethnicity, age, DCC size, previous DCC attendance and season were examined and did not account for the association observed between recent enrollement and risk of diarrheal illness. Rotavirus was identified in 18% of cases of diarrhea, but no association was seen with recent enrollment in DCC. A significantly higher incidence of diarrhea occurred in males compared with females (P less than 0.002) and in younger children (P less than 0.001) compared with older children. Diarrhea is common in children in DCCs and occurs significantly more frequently in children during their first 4 weeks in a DCC.

Age Factors↗
PubMed1991

Risk of enteric infection associated with child day care.

Pediatricians may advise parents that diarrhea is a frequent occurrence among infants and toddlers in day care and that diarrhea is usually mild and self-limited. A child newly enrolled in a day-care facility is at a particularly high risk for developing a diarrheal illness within the first month after enrollment, but the risk has been found to decrease as children remain in the same setting. Children who have diarrhea, fever, or vomiting of infectious origin should be isolated from well children. Infants and toddlers may return to the day-care environment when their diarrhea subsides and they are feeling well. Transmission of enteric infection from the child attending day-care center to other members of the family is possible; therefore, family members should also routinely practice good hygiene. Child-care providers should enforce written guidelines that establish hygienic practices and outline the management of ill children. Parents should be encouraged to read these policies and observe practices within the child-care setting before deciding to enroll their child in any care setting. The National Standards for out-of-home child care scheduled for release in 1991 will be important reading and a comprehensive reference for pediatricians who choose to be a child health consultant to one or more day-care facilities.

Child Day Care Centers↗
PubMed1991

Knowledge and attitudes of day care center parents and care providers regarding children infected with human immunodeficiency virus.

It was hypothesized that parents and child care providers are not prepared to accept children infected with human immunodeficiency virus (HIV), who are increasing in number, into the day care center setting. To determine their knowledge and attitudes toward HIV transmission, 219 parents in 4 day care centers and 176 care providers in 12 day care centers were given confidential questionnaires. More than 98% of respondents knew that sex and needle sharing can transmit HIV; 84% of parents and 77% of care providers knew that contact with blood can transmit HIV. There was, however, uncertainty about transmission via many common contacts in day care centers: human bites, urine, stool, tears, and vomit; kissing; sharing of food and eating utensils; and diaper changing areas. Only 43% of parents said they would allow their child to stay in the same room with a child who was infected with HIV. In a multiple logistic regression model, the unwillingness of parents to have their child stay in the same room with a child who was infected with HIV was significantly (P less than .0001) associated with black ethnicity, beliefs that such a child is likely to infect others (40%) and is dangerous to others (58%), and fear of their child being exposed to HIV (86%). Care providers' unwillingness to care for a child infected with HIV in the classroom (48%) was significantly (P less than .0001) associated with beliefs that such a child is likely to infect others (44%) and that common day care center contacts can transmit HIV (62%).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗