Human cytomegalovirus a sequence and UL144 variability in strains from infected children

Human cytomegalovirus (HCMV) displays genetic polymorphisms. This variability may contribute to strain-specific tissue tropism and disease expression in HCMV-infected humans. To determine strain variability in a sequence and UL144 gene regions, 51 low-passage isolates from 44 HCMV-infected children were studied. Isolates were obtained from 28 healthy children attending child care centers in Iowa and from 16 congenitally infected infants born in Texas. Isolates demonstrated substantial nucleotide variation in each gene region. Phylogenetic analysis of a sequence variability allowed 39 isolates to be grouped into six clades. The largest clade contained 16 isolates with > or = 95% nucleotide homology. Forty-eight of the 49 HCMV isolates yielding UL144 amplicons was grouped according to the clades described a few years ago [Lurain et al. (1999) Journal of Virology 73:10040-10050]. No linkage was observed among a sequence, UL144, and glycoprotein B (gB; UL55) polymorphisms. Four Texas and 11 Iowa isolates displayed > or = 95% sequence homology for a sequence and UL144 regions and possessed identical gB genotypes. No relationship between UL144 polymorphisms and outcome of congenital HCMV infection was observed. These data indicate that HCMV strains circulating among young children have UL144 polymorphisms similar to those of HCMV strains excreted by immunocompromised adults. Identification of conserved nucleotide sequences among Iowa and Texas children suggests genetic stability and biologic importance of these gene regions.

Characterization of human cytomegalovirus strains by analysis of short tandem repeat polymorphisms

Human cytomegalovirus (HCMV) strains display genetic polymorphisms, and these polymorphisms can be analyzed to study viral transmission and pathogenesis. Recently, short tandem repeat (STR) length polymorphisms have been identified in the HCMV genome. We assessed the utility of STRs in characterizing HCMV strains and found that a multiplexed PCR assay using primers based upon these STRs accurately maps HCMV strains. Using primers for 10 microsatellite regions, the STR profiles of 44 wild-type and 2 laboratory strains of HCMV were characterized. The results of STR analysis were compared with those for strain characterization using nucleotide sequencing and restriction fragment length polymorphism analysis. In each instance, STR analysis accurately and specifically identified strains that were indistinguishable or distinct by conventional molecular analysis. Analysis of short tandem repeats also detected polymorphisms that supported simultaneous excretion of two HCMV strains. These results indicate that STR analysis allows rapid, precise molecular characterization of HCMV strains.

Intrauterine cytomegalovirus infection and glycoprotein B genotypes

Cytomegalovirus (CMV) strains display polymorphisms for the gene encoding glycoprotein B (gB; gpUL55). Recent data suggest that the gB genotype may influence the outcome of acquired CMV infections. To determine whether the gB genotype also contributes to the outcome of intrauterine infection, CMV strains were studied from 56 infants with culture-confirmed intrauterine CMV infections who were born in Iowa or Texas. CMV gB genotypes were compared with the neonatal clinical features and neurodevelopmental outcomes. Fifty-three strains (95%) could be assigned a gB genotype. The overall distribution of genotypes was as follows: type 1, 50%; type 2, 18%; type 3, 23%; and type 4, 4%. Strains with the gB 3 genotype were more common among the Iowa infants (P=.082). The gB 3 genotype was more common among infants with asymptomatic infections (P=.004), but geographic location and ascertainment biases may have accounted for these differences. The gB genotypes did not correlate with the neurodevelopmental outcome of intrauterine infection.

How much antibiotic suspension is enough?

OBJECTIVES

Pilot data suggest that inadequate antibiotic volumes are often dispensed. Study goals were to determine the frequency of inadequate antibiotic volumes dispensed by local pharmacies, develop prescription-writing guidelines to ensure that adequate antibiotic suspension volumes are dispensed, and document the adequacy of verbal/written counseling pharmacists provide.

METHODS

Sixty-one local pharmacies filled prescriptions for penicillin potassium (PCN; 250 mg/5 mL [5 mL orally 3 times daily for 10 days]) and Bactrim (trimethoprim-sulfamethoxazole [TMP-SMX] 5 mL orally twice daily for 10 days). The prescriptions noted only to "dispense a 10-day supply. " Volumes were measured first as total amount dispensed and then into total doses dispensed. Written/verbal instructions were documented.

RESULTS

The volume of PCN dispensed was 195 +/- 25 mL (range: 105-222 mL) for an average of 29.4 doses, where 30 doses were needed. TMP-SMX dispensed had a volume of 107 +/- 5 mL (range: 98-120 mL) resulting in an average of 16.5 doses, where 20 doses were needed. Twenty pharmacies (33%) did not dispense a measuring device. Verbal counseling by the pharmacist and written instructions were not uniformly given.

CONCLUSIONS

We suggest calculating the actual volume needed plus an additional 10% to 30% of volume (depending on the viscosity). The prescription should also request a medication-measuring/administering device. Patient counseling and instruction should be expanded.

Cytomegalovirus transmission in child care homes

BACKGROUND

Children attending child care centers have high rates of cytomegalovirus (CMV) excretion. Women exposed to such children have an increased risk of acquiring CMV infection, and primary infection places the offspring of such women at risk of congenital CMV infection. We studied family child care homes to determine if this child care alternative might represent a safe haven from CMV.

METHODS

One hundred thirty-two women providing care in their homes were studied using a latex agglutination method to determine the rate of CMV seropositivity at baseline. Women who were seronegative for CMV were then sampled prospectively at 6-month intervals between March 1991 and August 1994 to determine the annual rate of CMV acquisition. A point prevalence of CMV excretion in family homes was determined by sampling 106 children from 25 randomly selected homes. Cytomegalovirus isolates were compared by molecular analysis using polymerase chain reaction-based methods to identify transmission.

RESULTS

At baseline, 57.6% of the 132 providers were seropositive for CMV. Seropositive providers were more likely to be caring for toddlers (aged 1-2 years) (67% vs 46%; P=.02) and had worked in child care somewhat longer (median of 28.5 vs 21.5 months; P=.11). Using stepwise logistic regression, the strongest predictors of seropositivity at baseline were caring for children aged 1 to 2 years (odds ratio [OR] =2.37; P=.02) and number of months as a child care provider (OR= 1.17 for an increase of 24 months as provider; P=.08). Six or more years as a provider was highly associated with seropositivity (OR=3.27; P=.02). During follow-up, 5 of 51 seronegative providers seroconverted, yielding an annual infection rate of 6.8%. The point prevalence survey of children from the 25 homes (14 had seropositive providers) identified 8 CMV-excreting children. Three children in 1 home had indistinguishable isolates by polymerase chain reaction mapping. The provider seroconverted and excreted an isolate with a molecular profile indistinguishable from that of the children.

CONCLUSIONS

The prevalence of CMV excretion is low among children attending child care homes (8% vs 15% in prior studies of child care centers; P=.07), and only 1 (20%) in 5 of the homes had CMV-excreting children. However, the overall CMV seroconversion rate of home child care providers was comparable to the rate observed among providers in child care centers. Families who use family home child care as an alternative to large child care centers are exposed to a low and unpredictable risk of CMV infection.

Epidemiology of congenital cytomegalovirus infection: maternal risk factors and molecular analysis of cytomegalovirus strains

To determine factors that influence the occurrence of congenital cytomegalovirus (CMV) infection, the authors surveyed prospectively 8,254 infants born in eastern Iowa between October 1989 and June 1994. The authors conducted a case-control study to identify maternal risk factors, matching each CMV-infected infant with three uninfected infants according to hospital and date of birth. CMV strains were compared by using the polymerase chain reaction (PCR) to identify common sources of infection. Of the 7,229 infants cultured successfully for CMV, 35 (0.48%) were congenitally infected. Mothers of CMV-infected infants were more likely to be single (odds ratio (OR) = 3.05, p = 0.016), to work in sales (OR = 4.93, p = 0.008), or to be students (OR = 5.01, p = 0.017). Conversely, women who worked in health-care professions were less likely to have a congenitally infected infant (OR = 0.14, p = 0.049). PCR analysis indicated 27 distinct strains of CMV, but two groups of infants (two infants per group) excreted strains with indistinguishable molecular patterns. One of these pairs of infants had older siblings who attended the same child-care center during their mothers' pregnancies. The authors concluded that demographic and occupational factors influenced the risk of giving birth to an infant with congenital CMV infection. Many distinct CMV strains were identified, suggesting that major point source outbreaks had not occurred. Nonetheless, point source acquisition of CMV from child-care environments did account for some cases of congenital CMV infection in eastern Iowa.

Infections of the central nervous system in the newborn

Safe, effective vaccines and potent antimicrobial agents have diminished substantially the morbidity and mortality associated with neonatal infections of the central nervous system (CNS), and new molecular methods, such as the polymerase chain reaction, enable clinicians to detect micro-organisms rapidly. Despite these advances, CNS infections remain an important cause of death and neurodevelopmental sequelae. This article summarizes current concepts regarding infections of the developing CNS.

Cytomegalovirus infection in newborns and their family members: polymerase chain reaction analysis of isolates

Polymerase chain reaction (PCR) analysis with primers for the pp65, a-sequence, glycoprotein B, and major immediate early genes of human cytomegalovirus (CMV) was used to study five congenitally-infected infants and their CMV-infected family members. Family members excreting CMV included three mothers and two siblings. The PCR results indicated that the CMV strain excreted by each infant was indistinguishable from that excreted by the corresponding family member. By contrast, the molecular profiles of the CMV strains were distinct between families, indicating that the PCR algorithm described in this study is a useful method for analyzing CMV strains.

Cytomegalovirus reinfection in young children

OBJECTIVE

To determine the frequency of reinfection with new cytomegalovirus (CMV) strains in children in group child-care environments.

METHODS

Ninety-two CMV strains isolated serially from children attending child care centers were analyzed. Strains were obtained from 1986 to 1994, from 37 children attending one of six centers in the area of Cedar Rapids and Iowa City, Iowa. The CMV isolates were analyzed by a polymerase chain reaction-based algorithm using primers for the a-sequence, glycoprotein B, and major immediate early (MIE) genes of human CMV. The a-sequence polymerase chain reaction products were compared on the basis of size, and products derived from glycoprotein B and MIE genes were compared according to restriction fragment length polymorphisms.

RESULTS

Children were between 8 months and 5 years 7 months of age at the time of CMV isolation. The number of isolates ranged from 2 to 6 per child, and the intervals between the first and last CMV isolation ranged from 11 weeks to more than 3 years. At least 7 (19%) of the 37 children had evidence of infection with more than one CMV strain. In six of these children, reinfection with distinct strains was confirmed by analysis of the MIE gene products of sequential CMV strains.

CONCLUSIONS

Children who attend child care centers, like adults who are immunosuppressed or have multiple sexual partners, are at risk of being reinfected with distinct CMV strains.

Rubella and syphilis: continuing causes of congenital infection in the 1990s

Despite an effective vaccine for rubella and reliable serological methods for detecting syphilis, these pathogens remain important potential causes of congenital infections. This article describes the epidemiological factors that have contributed to the reemergence of these disorders and summarizes the clinical features, microbiological diagnosis, and strategies for treatment or prevention of congenital rubella and congenital syphilis.

Analysis of acquired human cytomegalovirus infections by polymerase chain reaction

We used the polymerase chain reaction and primers corresponding to three regions of the human cytomegalovirus (HCMV) genome to study HCMVs isolated from 16 children attending a single day-care center and the father of two children in the same center. When we analyzed isolates with primers for the pp65 and major immediate-early genes, we observed nearly uniform amplification yielding products of predicted sizes. By contrast, primers for the a sequence demonstrated variability among HCMV strains, supporting the use of these primers as an epidemiologic tool. Analysis of a-sequence products from two isolates demonstrated 50 to 70% nucleotide homology with the a sequence of HCMV Towne strain DNA. We observed 95% nucleotide homology for the two a-sequence products derived from the father-child pair. Analysis of day-care center isolates indicated that two children excreted two distinct HCMV strains during the study interval.

Is treatment of acute otitis media with once-a-day amoxicillin feasible? Results of a pilot study

We report a study of the feasibility of once-a-day amoxicillin to treat acute otitis media (AOM). Seventy-seven children between ages 7 months and 12 years with AOM participated in a double-blind, placebo-controlled trial. Subjects received amoxicillin 40 mg/kg/day for 10 days. They were similar in age, sex, history of ear infections, and presenting symptoms. Group I received one total dose of amoxicillin and two doses of placebo daily. Group II received three divided doses of amoxicillin daily. Parents kept a daily diary of symptoms related to the child's illness and possible medication side effects. Ten children were lost to follow-up. In the remaining 67, pneumatic otoscopy and tympanometry after 10 to 14 days revealed that AOM had resolved in 82% of group I and 68% of group II. Groups showed no significant differences in persistence of middle ear effusion; 39% in group I and 24% in group II still had fluid. Diaries showed no significant differences between groups in medication side effects. Thus, reduced-frequency dosing for AOM seems feasible and more realistic than current regimens.

Physicians treating their own children

OBJECTIVES

To determine the types of health care interventions physicians provided to their own children, identify those conditions most often treated by physician-parents, compare the differences in treatment practices among physician groups, and explore the reasons physicians give for treating their own children.

DESIGN

Questionnaire.

SETTING

University-affiliated teaching hospital in Iowa City, Iowa.

PARTICIPANTS

Three hundred fifty-three physicians in residency and fellowship training and faculty who were parents of children aged 18 years or younger.

INTERVENTIONS

None.

MEASUREMENTS/MAIN RESULTS

The majority of physicians reported treating their afebrile child for acute illness. Fifty-five percent of physicians reported that they rarely or never treated their febrile child (temperature > 38.3 degrees C) without consultation with the child's physician. Only 47% of physicians reported that they always performed a physical examination on their child before treating. Physician-parents were more likely to auscultate the child's chest or perform otoscopy and less likely to obtain urine samples or throat swabs for culture before treating. Sixty-two percent of physicians reported that they have never performed routine health maintenance examinations on their own children, but 29% referred their children to a specialist. Medications were prescribed for their children by 65% of physicians. Neither gender nor level of training influenced the treatment practices of physician-parents. Primary care physicians were less likely to contact the child's physician for advice in treating their febrile child than were subspecialists. Pediatricians more often treated their afebrile and febrile children, performed physical examinations and laboratory studies, and prescribed medications than did other primary care physicians. Convenience was the most important reason physicians gave for treating their own children.

CONCLUSIONS

Physicians frequently treat their own ill children, prescribe medications for them, and self-refer them to specialists largely for the sake of convenience.

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.

Congenital infections and the nervous system

Despite vaccines, new antimicrobials, and improved hygienic practices, congenital infections remain an important cause of death and long-term neurologic morbidity among infants world-wide. Important agents include Toxoplasma gondii, cytomegalovirus, Treponema pallidum, herpes simplex virus types 1 and 2, and rubella virus. In addition, several other agents, such as the varicella zoster virus, human parvovirus B19, and Borrelia burgdorferi, can potentially infect the fetus and cause adverse fetal outcomes. This article provides an overview of these infectious disorders and outlines current strategies for acute treatment and long-term management.

Sabin inactivated trivalent poliovirus vaccine: first clinical trial and seroimmunity survey

The most widely used poliovaccine in the United States contains the three live attenuated strains originally produced by Sabin. An inactivated ("killed") formulation of this trivalent polio vaccine has now been prepared. Before testing this new vaccine, we assessed the poliovirus immune status of 39 healthy adult males between the ages of 20 and 44 years and found that 69% had detectable (titer greater than or equal to 1:4) neutralizing antibody to all three types of poliovirus, whereas 31% lacked antibody to 1 or more types even though they had a history of childhood polio immunization. Of interest, the lowest levels of neutralizing antibody were found among young adults in their late 20s, 2 of whom lacked antibody to all 3 polio types. When the Sabin inactivated trivalent poliovirus vaccine was initially administered to 12 seropositive volunteers, all responded with rising titers of neutralizing antibody that persisted for at least 18 months (range, 1:249 to 1:4948). The new vaccine was also given to a second group of 9 individuals with little or no detectable neutralizing antibody to at least one poliovirus type and again all vaccinees manifested a humoral immune response to poliovirus. Except for transient local tenderness at the injection site, no untoward reactions to immunization were observed. Thus, this Phase I study (1) confirmed earlier reports that titers of poliovirus antibody may decline to undetectable levels by early adulthood and (2) demonstrated that adults previously immunized with poliovirus vaccine responded rapidly to all 3 poliovirus types (within 7 days) upon reimmunization with Sabin inactivated trivalent vaccine whether or not there was preexisting detectable antibody.

The natural history of acquired cytomegalovirus infection among children in group day care

We studied the natural history of cytomegalovirus (CMV) excretion among 79 children in a single day-care center over a 2 1/2-year period. During the study interval, 28 children (35%) excreted CMV in their urine, or saliva, or both. The CMV acquisition rate among children who were initially culture negative was 12.6% per year. In such children, CMV excretion began 11 to 59 months after entry into day care. The duration of CMV excretion varied from 3.0 to 28.4 months, with a mean of 13.0 +/- 9.1 months for urine and 7.0 +/- 2.7 months for saliva. The quantity of CMV in saliva or urine was highest during the first three months of excretion, as high as 10(5) 50% tissue culture infectious dose per milliliter. Children excreting CMV entered day care at a younger age (mean, 5.3 +/- 8.5 months for excretors vs 12.7 +/- 14.8 months for nonexcretors) and spent more hours in day care per week than the nonexcretors (mean, 41.8 +/- 9.0 h/wk for excretors vs 36.1 +/- 10.9 h/wk for nonexcretors).

Risk of cytomegalovirus infection among educators and health care personnel serving disabled children

To determine the risk of cytomegalovirus (CMV) infection for personnel who provide services to young disabled children, we studied the prevalence of CMV infection among such children and determined the seroconversion rate among exposed personnel. The prevalence of CMV excretion was 9.8% among children aged 0 to 5 years in a University-based outpatient program vs. 3.3% in 3- to 5-year-old children attending community-based preschools. Initial serologic studies of personnel demonstrated no differences in CMV seropositivity rates among staff with occupational child contact vs. staff without such contact (40% (40 of 99) vs. 34% (26 of 77] (P = 0.37). However, 21 of the 31 personnel 40 years and older who had occupational child contact were seropositive vs. 10 of 26 personnel of comparable age who had no occupational child contact (P = 0.026). During a 1-year follow-up, 2 of 86 (2.3%) susceptible personnel seroconverted. Rates were 4.4% (2 of 45) among staff with occupational child contact vs. no seroconversions (0 of 41) for those without (P = 0.27). These results indicate that the risk of CMV infection for personnel who work with disabled children is low. However, we cannot exclude the possibility that there may be a small cumulative risk of CMV infection that may exceed that of adults who do not have occupational contact with children.

Survival of cytomegalovirus in paper diapers and saliva

We studied the survival of human cytomegalovirus inoculated experimentally into saliva and urine-soaked paper diapers. Infectious virus could be recovered from saliva maintained at room temperature or 37 degrees C for up to 2 hours after inoculation. Cytomegalovirus survived in paper diapers for periods as long as 48 hours, with the quantity of virus in urine remaining relatively constant for the initial 12 hours. These observations provide further support for the concept that fomites may have a role in the transmission of cytomegalovirus infections.

Cytomegalovirus transmission in a Midwest day care center: possible relationship to child care practices

The epidemiology of cytomegalovirus (CMV) infection and transmission in a large Iowa day care center was studied. Over the 9 months of the study the overall CMV prevalence rates were 21% to 22%, with rates as high as 71% in toddlers. Titers of CMV in the urine or saliva of infected children were as high as 3 X 10(4) plaque-forming units of CMV per milliliter, similar to titers of CMV observed in some congenitally infected infants. Restriction enzyme analysis of CMV isolates from children in the center demonstrated two major clusters with similar patterns, one among 2- and 3-year-old children and another among infants. The clustering of similar CMV isolates among nonambulatory infants suggests that child care or hygienic practices may contribute to the spread of CMV infection in day care centers. Furthermore, the relatively high prevalence of CMV excretion in this center and the low seropositivity rates to CMV among adults in Iowa suggest that adults in the Midwest who have contact with children in day care centers may be at risk for primary CMV infection.