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Cytomegaloviruria in older infants in intensive care nurseries
September 1979
444
TheJournalofPEDIATRICS
Cytomegaloviruria in older infants in intensive care nurseries Over a four-month period, urine specimens for viral isolation were obtained weekly from all infants older than three weeks in two intensive care nurseries. These babies comprised 43% of the patients in the nurseries surveyed. Cytomegalovirus was cultured from 13 of 93 (14%) of these infants. Eleven of 13 infants who developed cytomegaloviruria were born prematurely, and nine of these 11 were found to be excreting C M V before they reached 40 weeks postconception. Infants excreting C M V received blood transfusions from a mean of 10.45 (+ 1.80 SE) different donors versus 5.10 (+ 0.55 SE) for infants without viruria (P < 0.002) and five of 14 infants undergoing one or more exchange transfusions developed cytomegaloviruria (P < 0.05). The possible role of other C M V reservoirs and the importance of these findings are discussed.
Stephen A. Spector, M.D.,* Kathleen Sehmidt, R.N., Warren Ticknor, B.S., and Moses Grossman, M . D . , S a n Franc&o, Calif.
C Y T O M E G A L O V I R U S h a s been shown to infect in u t e r o 0.5 to 2.0% of all newborn infants?' 2 Although most infants infected at birth are initially asymptomatic, approximately 5 to 15% develop sensorineural hearing deficits or other central nervous system abnormaIities.3-~ Infants in intensive care nurseries are stressed by prematurity, cardiopulmonary disease, and other life-threatening conditions. They usually receive frequent blood transfusions and are exposed to other potential sources of CMV. The present study was designed to determine the incidence of cytomegaloviruria in infants greater than 3 weeks of age in two intensive care nurseries.
MATERIALS AND METHODS All infants greater than three weeks of age hospitalized in the University of California, San Francisco Intensive Care Nursery or in the Children's Hospital Medical Center of Oakland Intensive Care Nursery from April to August, 1978, had bagged urine specimens for virus From the Department of Pediatrics, San Francisco General Hospital and University of California, San Francisco. Supported in part by the Bay Area Chapter of the March of Dimes-National Foundation. *Reprint address: Department of Pediatrics, M-O09, University of California, San Diego, La Jolla, CA 92093.
Vol. 95, No. 3, pp. 444-446
isolation obtained weekly until discharge. Both nurseries are level three infant intensive care units in which medical care is provided by nurse specialists, pediatric house officers, and fellows under the supervision of Boardcertified neonatologists. All infants in the CH-ICN and approximately half of the babies in the UCSF-ICN were transported into these units soon after birth from other hospitals. Abbreviations used CMV: cytomegalovirus UCSF-ICN: University of California, San Francisco Intensive Care Nursery CH-ICN: Childt~en'sHospital Medical Center of Oakland Intensive Care Nursery HEL: human embryonic lung
VIRAL ISOLATION Urine was obtained from freshly voided specimens and diluted 1:1 with maintenance medium containing penicillin, gentafnicin and amphotericin B, and 0.25 ml of the mixture was inoculated into each of four human embryonic lung fibroblast monolayer culture tubes (Flow Laboratories) and held in stationary cultures at 37~ CMV was identified by its characteristic cytopathic effect, its ability to be passaged to other HEL culture tubes, and by its failure to replicate in monkey kidney cell lines. At
0022-3,~76/79/090444+03500.30/0 9 1979 The C.V. Mosby Co.
Volume 95 Number 3
least one tube from each set of cultures was maintained for a minimum of four weeks before being considered negative.
Cytomegaloviruria
Table I. Comparison of infants hospitalized in two intensive care nurseries UCSF-ICN CH-ICN
RESULTS Over the four-month study period, 99 infants reached 3 weeks of age while hospitalized in one of the study nurseries. Adequate cultures were obtained from 93 infants; urine specimens obtained from the other six infants were consistently contaminated. The principal diagnoses requiring extended hospitalization were prematurity, hyaline membrane disease, and congenital heart disease. Babies older then 3 weeks of age comprised 43% of all infants in the combined nurseries on study days (39% of the daily census at UCSF-ICN and 46% of daily totals at CH-ICN) (Table I). At the UCSF-ICN, five of 39 (13%) infants cultured were found to be excreting CMV in their urme: at the CH-ICN, eight of 54 (15%) had cytomegaloviruria. Therefore. 14% of all infants screened were excreting CMV. No other viruses were isolated from urine specimens during the study. Eleven of 13 infants (85%) with cytomegaloviruria were born prematurely; nine of these 11 babies (82%) were documented to be excreting CMV before they reached 40 weeks postconception. Three infants hospitalized in the intensive care nurseries from 28 to 154 days were noted to be excreting CMV during the first week of the study. Initial urine samples obtained at 3 weeks of age or greater were positive from seven of 13 (54%) infants found to be excreting CMV. The other six infants developed cytomegaloviruria between 4 and 9 weeks of age following initially negative cultures. Once one culture was positive for CMV. all infants continued to have cytomegaloviruria for the duration of their hospital stay or for the duration of the study. All infants excreting CMV in their urine had received prior blood transfusions. Babies with cytomegaloviruria received blood from a mean of 10.45 ( _ 1.80 SE) different donors versus 5.10 ( + 0.55 SE) for CMV negative infants (P < 0.002) (Table II). A statistically significant number of infants (five of 14) receiving one or more exchange transfusions developed cytomegaloviruria during their hospitalization (P < 0.05). Human milk was used in only two of 13 (15%) infants with cytomegaloviruria, and only one of 13 babies received breast milk which had not been frozen. Three of 13 (23%) CMV-positive infants were born via cesarean section. No symptoms suggestive of infection were noted at the time of virus isolation in ten of 13 (77%) infants. However, three infants had cyanosis and apnea associated with increased ventilatory requirements. One of these three infants was in chronic congestive heart failure and died following
445
Census on culture days* Infants > 3 wk on culture days* (%) Total infants > 3 wk of age Total infants with adequate Cultures CMV positive (%)
Total
18 7 (39)
28 13 (46)
46 20 (43)
40 39
59 54
99 93
5 (13)
8 (15)
13 (14)
*Mean number. Table II. Association of blood transfusions with cytomegaloviruria C M V (+)
C M V (--)
Total infants 13 80 Infants with exchange transfu5 9* sions No. of blood donors 0 0 9 1-5 3 37 6-10 3 19 11-15 2 5 15 3 3 Infants with complete donor 11 73 histories available Mean donors (_+SE) 10.45 (+_ 1.80) 5.10 (_+ 0.55)t *P < 0.05 (Chic-squareusingYates correction). "~P< 0.002(Student t test). surgery for her complex congenital heart disease. All three were being evaluated for sepsis at the time that cytomegalovirus was cultured from their urine. DISCUSSION Several studies have documented that infants are at risk for acquiring CMV infections during their hospitalization in intensive care nurseries.6' ~ We chose to study infants older than 3 weeks because we had previously found four of 240 babies evaluated for sepsis to be excreting CMV in their urine; all four of these infants were initially CMV negative and developed viruria at 18 days of age or older9 These infants comprised 15% of older babies suspected of sepsis. In the present study, we have found that 14% of all infants greater than three weeks of age were excreting CMV. These data, combined with our original findings, suggest that most of the present infants found to have viruria at initial culture acquired CMV either natally or postnatally, and were not congenitally infected. In addition, since this study was designed to document cytome-
446
Spector et al.
ga!oviruria, n o t seroconversion, the 14% o f older babies who actively excreted C M V p r o b a b l y represent only some of the infants who a c q u i r e d C M V infection. The source(s) of C M V in these infants are uncertain. A p p r o x i m a t e l y 5% o f all b l o o d donors are capable o f transmitting C M V r 9 Several reports h a v e associated blood transfusions, followed b y Epstein-Barr virus negative infectious mononucleosis, with the isolation o f CMV.10 x~ Infants transfused in the n e w b o r n period. w h e n studied at 7 m o n t h s o f age, have a higher incidence of past exposure to C M V t h a n controls w h o have received no transfusions (25% versus 11%). 12 In one study, 20% o f n e w b o r n infants receiving e x c h a n g e transfusions subsequently h a d serologic evidence of C M V infection. 13 O u r data implicate b l o o d transfusions as o n e Source of C M V in n e w b o r n infections a n d f u r t h e r d o c u m e n t the high association o f C M V with e x c h a n g e transfusions. R e a c t i v a t i o n of C M V is a c o m m o n occurrence in the third trimester of pregnancy, TM and~ nafal acquisition o f C M V by those n e w b o r n infants b o r n by vaginal deliveries must be c o n s i d e r e d ? ~ W e could not implicate breast milk as a m a j o r reservoir o f virus. T h e i m p o r t a n c e o f n o s o c o m i a l acquisition of C M V by babies from other infants or from medical p e r s o n n e l also remains u n a n s w e r e d . Presently, it is felt that close contact is necessary for transmission o f CMV. T h e present study emphasizes the i m p o r t a n c e o f establishing the risks which infants excreting C M V pose to other infants and to p r e g n a n t personnel. O u r data imply that a 20 bed intensive care nursery will h a v e eight infants older than 3 weeks of age, a n d t h a t one o f t h e b a b i e s will be actively excreting C M V : A l t h o u g h natally a c q u i r e d C M V in term babies has not b e e n s h o w n to be associated With n e u r o logic sequelae, the prognosis for p r e m a t u r e infants w h o develop C M V infections in essentially their third trimester p o s t c o n c e p t i o n remains to b e defined. Finally, since blood transfusions are strongly associated with acquired C M V in the n e o n a t a l period; practical m e a n s o f r e d u c i n g C M V transmission t h r o u g h blood products need to be explored. The authors thank the neonatologists, the nurses, and the housestaffs at the University of California. San Francisco Inten-
The Journal of Pediatrics September 1979
sive Care Nursery and the Children's HospitalMedical Center of Oakland Intensive Care Nursery for their cooperation in the conduct of this study.
REFERENCES
'1. Starr JG, Bort RD. and Gold E: Inapparent congenital cytomegalovirus infection: Clinical and epidemiologic characteristics in early infancy, N Engl J Med 282:1075. 1970. 2. Hanshaw JB: Congenital cytomegalovirus infection: A fifteen year perspective. J Infect Dis 123:555. 1971. 3. Melish ME. and Hanshaw JB: Congenita! cytomegalovirus infection: Developmental progress of infants detected by routine screening, Am J Dis Child 126:190. 1973. 4. Kumar ML. Nankervis G. and Gold E: lnapparent congenital cytomegalovirus infection: A follow-up study, N Engl J Med 288:1370. 1973. 5. Stagno S. Reynolds RW. Amos CS. et al: Auditory and visual defects resulting from symptomatic and subclinical congenital cytomegaloviral and toxoplasma infection. Pediatrics 59:669. 1977. 6. Whitley RJ~ Brasfield D. Reynolds DW. Stagno S. Tiller RE. and Alford CA: Protracted pneumonitis in young infants associated with perinatally acquired cytomegaloviral infection. J PEDIATR89:16. 1976. 7. Yeager AS. Jacobs H. and Clark MS: Nursery-acquired cytomegalovirus infection in two premature infants. J PEDIATR 81:332. 1972. 8. Diosi P. Moldovan E. and Tomescu N: Latent cytomegalovirus infection in blood donors. Br Med J 4:660. 1969. 9. Perham TGM. Caul EO. Conway PJ. and Mott MG: Cytomegalovirus infection in blood donors: A prospective study, Br J Haematol 20:307. 1971. 10. Kaariainen L. Klemola E. and Paloheimo J: Rise of cytomegalovirus antibodies in an infectious-mononucleosis-like syndrome after transfusion. Br Med J 1:1270. 1966. 11. Foster KM, and Jack I: A prospective study of the role of cytomegalovirus in post-transfusion mononucleosis. N Engl J Med 280:1311. 1969. 12. YeagerAS: Transfusion acquired cytomegalovirus infection m newborn infants: Am J Dis Child 128:478. 1974. 13. Nankervis GA: Cytomegalovirus infections in the blood recipient, Yale J Biol Med 49:13, 1976. 14. Montgomery R. Youngblood L. and Medearis DN: Recovery of cytomegalovirus from cervix on pregnancy, Pediatrics 49:524. 1972. 15. Kumar ML. Gold E. and Nankervis G: Risk of acquired cytomegalovirus infection in infants of maternal cytomegalovirus excretors. Pediatr Res 9:342. 1975.
444
TheJournalofPEDIATRICS
Cytomegaloviruria in older infants in intensive care nurseries Over a four-month period, urine specimens for viral isolation were obtained weekly from all infants older than three weeks in two intensive care nurseries. These babies comprised 43% of the patients in the nurseries surveyed. Cytomegalovirus was cultured from 13 of 93 (14%) of these infants. Eleven of 13 infants who developed cytomegaloviruria were born prematurely, and nine of these 11 were found to be excreting C M V before they reached 40 weeks postconception. Infants excreting C M V received blood transfusions from a mean of 10.45 (+ 1.80 SE) different donors versus 5.10 (+ 0.55 SE) for infants without viruria (P < 0.002) and five of 14 infants undergoing one or more exchange transfusions developed cytomegaloviruria (P < 0.05). The possible role of other C M V reservoirs and the importance of these findings are discussed.
Stephen A. Spector, M.D.,* Kathleen Sehmidt, R.N., Warren Ticknor, B.S., and Moses Grossman, M . D . , S a n Franc&o, Calif.
C Y T O M E G A L O V I R U S h a s been shown to infect in u t e r o 0.5 to 2.0% of all newborn infants?' 2 Although most infants infected at birth are initially asymptomatic, approximately 5 to 15% develop sensorineural hearing deficits or other central nervous system abnormaIities.3-~ Infants in intensive care nurseries are stressed by prematurity, cardiopulmonary disease, and other life-threatening conditions. They usually receive frequent blood transfusions and are exposed to other potential sources of CMV. The present study was designed to determine the incidence of cytomegaloviruria in infants greater than 3 weeks of age in two intensive care nurseries.
MATERIALS AND METHODS All infants greater than three weeks of age hospitalized in the University of California, San Francisco Intensive Care Nursery or in the Children's Hospital Medical Center of Oakland Intensive Care Nursery from April to August, 1978, had bagged urine specimens for virus From the Department of Pediatrics, San Francisco General Hospital and University of California, San Francisco. Supported in part by the Bay Area Chapter of the March of Dimes-National Foundation. *Reprint address: Department of Pediatrics, M-O09, University of California, San Diego, La Jolla, CA 92093.
Vol. 95, No. 3, pp. 444-446
isolation obtained weekly until discharge. Both nurseries are level three infant intensive care units in which medical care is provided by nurse specialists, pediatric house officers, and fellows under the supervision of Boardcertified neonatologists. All infants in the CH-ICN and approximately half of the babies in the UCSF-ICN were transported into these units soon after birth from other hospitals. Abbreviations used CMV: cytomegalovirus UCSF-ICN: University of California, San Francisco Intensive Care Nursery CH-ICN: Childt~en'sHospital Medical Center of Oakland Intensive Care Nursery HEL: human embryonic lung
VIRAL ISOLATION Urine was obtained from freshly voided specimens and diluted 1:1 with maintenance medium containing penicillin, gentafnicin and amphotericin B, and 0.25 ml of the mixture was inoculated into each of four human embryonic lung fibroblast monolayer culture tubes (Flow Laboratories) and held in stationary cultures at 37~ CMV was identified by its characteristic cytopathic effect, its ability to be passaged to other HEL culture tubes, and by its failure to replicate in monkey kidney cell lines. At
0022-3,~76/79/090444+03500.30/0 9 1979 The C.V. Mosby Co.
Volume 95 Number 3
least one tube from each set of cultures was maintained for a minimum of four weeks before being considered negative.
Cytomegaloviruria
Table I. Comparison of infants hospitalized in two intensive care nurseries UCSF-ICN CH-ICN
RESULTS Over the four-month study period, 99 infants reached 3 weeks of age while hospitalized in one of the study nurseries. Adequate cultures were obtained from 93 infants; urine specimens obtained from the other six infants were consistently contaminated. The principal diagnoses requiring extended hospitalization were prematurity, hyaline membrane disease, and congenital heart disease. Babies older then 3 weeks of age comprised 43% of all infants in the combined nurseries on study days (39% of the daily census at UCSF-ICN and 46% of daily totals at CH-ICN) (Table I). At the UCSF-ICN, five of 39 (13%) infants cultured were found to be excreting CMV in their urme: at the CH-ICN, eight of 54 (15%) had cytomegaloviruria. Therefore. 14% of all infants screened were excreting CMV. No other viruses were isolated from urine specimens during the study. Eleven of 13 infants (85%) with cytomegaloviruria were born prematurely; nine of these 11 babies (82%) were documented to be excreting CMV before they reached 40 weeks postconception. Three infants hospitalized in the intensive care nurseries from 28 to 154 days were noted to be excreting CMV during the first week of the study. Initial urine samples obtained at 3 weeks of age or greater were positive from seven of 13 (54%) infants found to be excreting CMV. The other six infants developed cytomegaloviruria between 4 and 9 weeks of age following initially negative cultures. Once one culture was positive for CMV. all infants continued to have cytomegaloviruria for the duration of their hospital stay or for the duration of the study. All infants excreting CMV in their urine had received prior blood transfusions. Babies with cytomegaloviruria received blood from a mean of 10.45 ( _ 1.80 SE) different donors versus 5.10 ( + 0.55 SE) for CMV negative infants (P < 0.002) (Table II). A statistically significant number of infants (five of 14) receiving one or more exchange transfusions developed cytomegaloviruria during their hospitalization (P < 0.05). Human milk was used in only two of 13 (15%) infants with cytomegaloviruria, and only one of 13 babies received breast milk which had not been frozen. Three of 13 (23%) CMV-positive infants were born via cesarean section. No symptoms suggestive of infection were noted at the time of virus isolation in ten of 13 (77%) infants. However, three infants had cyanosis and apnea associated with increased ventilatory requirements. One of these three infants was in chronic congestive heart failure and died following
445
Census on culture days* Infants > 3 wk on culture days* (%) Total infants > 3 wk of age Total infants with adequate Cultures CMV positive (%)
Total
18 7 (39)
28 13 (46)
46 20 (43)
40 39
59 54
99 93
5 (13)
8 (15)
13 (14)
*Mean number. Table II. Association of blood transfusions with cytomegaloviruria C M V (+)
C M V (--)
Total infants 13 80 Infants with exchange transfu5 9* sions No. of blood donors 0 0 9 1-5 3 37 6-10 3 19 11-15 2 5 15 3 3 Infants with complete donor 11 73 histories available Mean donors (_+SE) 10.45 (+_ 1.80) 5.10 (_+ 0.55)t *P < 0.05 (Chic-squareusingYates correction). "~P< 0.002(Student t test). surgery for her complex congenital heart disease. All three were being evaluated for sepsis at the time that cytomegalovirus was cultured from their urine. DISCUSSION Several studies have documented that infants are at risk for acquiring CMV infections during their hospitalization in intensive care nurseries.6' ~ We chose to study infants older than 3 weeks because we had previously found four of 240 babies evaluated for sepsis to be excreting CMV in their urine; all four of these infants were initially CMV negative and developed viruria at 18 days of age or older9 These infants comprised 15% of older babies suspected of sepsis. In the present study, we have found that 14% of all infants greater than three weeks of age were excreting CMV. These data, combined with our original findings, suggest that most of the present infants found to have viruria at initial culture acquired CMV either natally or postnatally, and were not congenitally infected. In addition, since this study was designed to document cytome-
446
Spector et al.
ga!oviruria, n o t seroconversion, the 14% o f older babies who actively excreted C M V p r o b a b l y represent only some of the infants who a c q u i r e d C M V infection. The source(s) of C M V in these infants are uncertain. A p p r o x i m a t e l y 5% o f all b l o o d donors are capable o f transmitting C M V r 9 Several reports h a v e associated blood transfusions, followed b y Epstein-Barr virus negative infectious mononucleosis, with the isolation o f CMV.10 x~ Infants transfused in the n e w b o r n period. w h e n studied at 7 m o n t h s o f age, have a higher incidence of past exposure to C M V t h a n controls w h o have received no transfusions (25% versus 11%). 12 In one study, 20% o f n e w b o r n infants receiving e x c h a n g e transfusions subsequently h a d serologic evidence of C M V infection. 13 O u r data implicate b l o o d transfusions as o n e Source of C M V in n e w b o r n infections a n d f u r t h e r d o c u m e n t the high association o f C M V with e x c h a n g e transfusions. R e a c t i v a t i o n of C M V is a c o m m o n occurrence in the third trimester of pregnancy, TM and~ nafal acquisition o f C M V by those n e w b o r n infants b o r n by vaginal deliveries must be c o n s i d e r e d ? ~ W e could not implicate breast milk as a m a j o r reservoir o f virus. T h e i m p o r t a n c e o f n o s o c o m i a l acquisition of C M V by babies from other infants or from medical p e r s o n n e l also remains u n a n s w e r e d . Presently, it is felt that close contact is necessary for transmission o f CMV. T h e present study emphasizes the i m p o r t a n c e o f establishing the risks which infants excreting C M V pose to other infants and to p r e g n a n t personnel. O u r data imply that a 20 bed intensive care nursery will h a v e eight infants older than 3 weeks of age, a n d t h a t one o f t h e b a b i e s will be actively excreting C M V : A l t h o u g h natally a c q u i r e d C M V in term babies has not b e e n s h o w n to be associated With n e u r o logic sequelae, the prognosis for p r e m a t u r e infants w h o develop C M V infections in essentially their third trimester p o s t c o n c e p t i o n remains to b e defined. Finally, since blood transfusions are strongly associated with acquired C M V in the n e o n a t a l period; practical m e a n s o f r e d u c i n g C M V transmission t h r o u g h blood products need to be explored. The authors thank the neonatologists, the nurses, and the housestaffs at the University of California. San Francisco Inten-
The Journal of Pediatrics September 1979
sive Care Nursery and the Children's HospitalMedical Center of Oakland Intensive Care Nursery for their cooperation in the conduct of this study.
REFERENCES
'1. Starr JG, Bort RD. and Gold E: Inapparent congenital cytomegalovirus infection: Clinical and epidemiologic characteristics in early infancy, N Engl J Med 282:1075. 1970. 2. Hanshaw JB: Congenital cytomegalovirus infection: A fifteen year perspective. J Infect Dis 123:555. 1971. 3. Melish ME. and Hanshaw JB: Congenita! cytomegalovirus infection: Developmental progress of infants detected by routine screening, Am J Dis Child 126:190. 1973. 4. Kumar ML. Nankervis G. and Gold E: lnapparent congenital cytomegalovirus infection: A follow-up study, N Engl J Med 288:1370. 1973. 5. Stagno S. Reynolds RW. Amos CS. et al: Auditory and visual defects resulting from symptomatic and subclinical congenital cytomegaloviral and toxoplasma infection. Pediatrics 59:669. 1977. 6. Whitley RJ~ Brasfield D. Reynolds DW. Stagno S. Tiller RE. and Alford CA: Protracted pneumonitis in young infants associated with perinatally acquired cytomegaloviral infection. J PEDIATR89:16. 1976. 7. Yeager AS. Jacobs H. and Clark MS: Nursery-acquired cytomegalovirus infection in two premature infants. J PEDIATR 81:332. 1972. 8. Diosi P. Moldovan E. and Tomescu N: Latent cytomegalovirus infection in blood donors. Br Med J 4:660. 1969. 9. Perham TGM. Caul EO. Conway PJ. and Mott MG: Cytomegalovirus infection in blood donors: A prospective study, Br J Haematol 20:307. 1971. 10. Kaariainen L. Klemola E. and Paloheimo J: Rise of cytomegalovirus antibodies in an infectious-mononucleosis-like syndrome after transfusion. Br Med J 1:1270. 1966. 11. Foster KM, and Jack I: A prospective study of the role of cytomegalovirus in post-transfusion mononucleosis. N Engl J Med 280:1311. 1969. 12. YeagerAS: Transfusion acquired cytomegalovirus infection m newborn infants: Am J Dis Child 128:478. 1974. 13. Nankervis GA: Cytomegalovirus infections in the blood recipient, Yale J Biol Med 49:13, 1976. 14. Montgomery R. Youngblood L. and Medearis DN: Recovery of cytomegalovirus from cervix on pregnancy, Pediatrics 49:524. 1972. 15. Kumar ML. Gold E. and Nankervis G: Risk of acquired cytomegalovirus infection in infants of maternal cytomegalovirus excretors. Pediatr Res 9:342. 1975.