Maternal Genital Bacteria and Surface Colonization in Early Neonatal Sepsis
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《美国医学杂志》
1 Department of Pediatrics,Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry., India
2 Department of Microbiology,Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry., India
3 Department of Obst and Gyanecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry., India
Abstract
Objective : The study was intended to evaluate the role of maternal genital bacteria and baby's surface colonization in early onset neonatal sepsis. Methods : Babies (born in the hospital of Jawaharlal Institute of Postgraduate Medical Education and Research) who developed clinical signs of sepsis were studied. Swabs were collected for culture from baby's umbilicus, ear, throat in addition to gastric aspirate and blood culture. The genital tract of the mother was also studied for bacterial colonization. The organisms isolated from the maternal genital tract and baby's surface colonization were correlated with those isolated from blood culture by calculating Phi correlation coefficient. Results : Esch coli was the most common organism isolated from maternal genital tract and surface cultures of babies, but Klebseilla-Spp was the most common organism isolated from blood. There was a significant correlation between surface colonization of babies and maternal genital bacteria, so also was baby's surface culture and blood culture. However, correlation between maternal genital bacteria and baby's blood culture was not significant. Conclusion: Surface colonizing bacteria and not maternal genital bacteria are important in early onset neonatal sepsis.
Keywords: Neonatal sepsis; Surface colonization; Maternal genital bacteria
Neonatal sepsis continues to be one of the leading causes of neonatal mortality in India, although its incidence in the west has shown a steady decline.[1] Early onset neonatal sepsis is commonly caused by microorganisms acquired from the mother before or during birth (vertically transmitted and perinatally acquired). Infections presenting after 7 days of birth are considered late onset infections and are generally caused by microorganisms acquired from the environment rather than from the mother (nosocomial and horizontally transmitted). Maternal genital tract organisms may play an important role in early onset sepsis, while environmental organisms have a vital role in late onset sepsis.[1] However, the demarcation is not very discrete. Neonatal risk factors for invasive bacterial disease and its diagnosis and therapy remain an important problem for obstetricians and pediatricians alike. The present study was conducted to find out the correlation between maternal genital bacteria, baby's surface colonization and neonatal sepsis.
Materials and methods
The present study involved 102 babies born in JIPMER hospital and were treated with antibiotics for clinical evidence of sepsis and positive screening test. A detailed history was obtained which included antenatal care, treatment received in other hospital, maternal fever within one week of delivery, history suggestive of urinary tract infection, any medical illness, anemia, history suggestive of intrauterine infection, quality of liquor, duration of labor, mode of delivery, Apgar score of babies and mode of resuscitation.
Gastric aspirate, swabs from throat, umbilicus, external auditory canal and skin of babies were obtained for culture studies. Blood samples were collected for septic screen and culture before starting antibiotics. Cerebrospinal fluid, urine and other appropriate body fluids were collected as and when indicated. Specimens obtained for culture were immediately plated on Mac-Conkey and blood agar for aerobic bacterial culture. Septic screening included total count, differential count, band cell count, micro ESR, and qualitative estimation of C reactive protein (CRP) by latex particle agglutination. Band cell count was considered as positive when percentage of band cells was more than 20% of total neutrophil count. Micro ESR was considered as positive when it was more than 15 mm or 3 mm above the age in days during the first hour. CRP estimation was done using "MEDI CRP" (Medicare diagnostics), which is a slide based latex assay for CRP.
High vaginal swabs were taken from mothers of these babies after informed consent Mother's hemoglobin and total leukocyte count were also obtained. Type of bacteria isolated from mother's genital tract and their antibiotic sensitivity pattern was studied. The babies received supportive care and antibiotic therapy as per our unit protocol. They were followed up till discharge. Organisms isolated from the baby and mother was correlated by calculating Phi correlation coefficient.
Results
Among 102 cases of early onset sepsis in the present study, 21 (20%) cases were found with positive blood culture. Neonatal surface colonization occurred in 37% and 24% cases due to Esch. coli and Klebsiella-Spp respectively in the present study. PROM for mothers was an important risk factor in early onset neonatal sepsis. In the present study 90.2% of the mothers had PROM of more than 12 hours and 70.6% had PROM for 12-24 hours. 83.4% babies with sepsis were preterm, 79.4% babies were between 30 to 36 weeks.
The most common symptom in early onset neonatal sepsis was respiratory distress followed by poor activity. Among Septic screen tests, micro ESR appeared to be the most sensitive test as it was positive in 93 % of cases with early onset sepsis, followed by CRP which was positive in 82.4%. Band count was positive in 63.7% of cases.
Maternal genital canal colonization was seen in 52 cases with early onset neonatal sepsis. Esch coli was the most common isolate followed by Klebsiella species. Group B streptococcus was observed in only one case. Multiple species of bacteria were seen in some mothers. The most common combination was that of Esch. coli with Klebsiella species table1.
Klebsiella-Spp was the most common bacteria isolated from blood culture in the present study, Klebsiella-Spp followed by Esch coli , Acinetobacter and Coagulase negative Staphylococci. Group B Streptococcus was isolated only in one case table1. Four babies in the present study expired and all of them had meningitis. Klebseilla-Spp was isolated from blood and cerebrospinal fluid in two of them.
There was a significant correlation between maternal genital tract bacteria and baby's surface colonization table2. Baby's surface colonization also had significant correlation with organism isolated from baby's blood. However, maternal genital bacteria did not have significant correlation with bacteria isolated from blood culture table3.
Discussion
The most common organism isolated from maternal genital tract was Esch coli followed by Klebsiella-Spp . But in western countries Gr B streptococcily BS was the most common organism implicated in maternal genital tract colonization.[2] In a study from Delhi the most common organism isolated from maternal genital tract was Esch. coli followed by Staphylococcus aureus and Klebsiella-Spp .[3] The variation of bacteria isolated from genital tract may represent regional variation of genital flora.
Respiratory distress was the most common symptom in the babies with sepsis, followed by poor activity and sclerema; similar observations were made by others.[4],[5] Mishra et al recorded 3.3% meningitis among babies with sepsis, while other authors have quoted incidence varying from 3% to 8%.[4],[5],[6],[7] Much higher incidence of meningitis i.e., 25% was recorded by others.[8] The incidence of meningitis appears to be decreasing now probably because of early intervention and higher antibiotics available at present.
Maternal fever also seemed to be an important risk factor as 49% babies in the present study were born to mothers with history of fever. An obstetric risk factor, intrapartum fever, or membrane rupture of 18 hours more were found in 49% of GBS cases and 79% of other sepsis in a case control study of early onset neonatal sepsis[9].The incidence of positive blood and superficial cultures increased significantly when the membranes ruptured for 24 hours or more prior to delivery. There was a three-fold increase in the incidence of sepsis when membranes ruptured for 24 hours prior to delivery.
Low birth weight and prematurity are important risk factors in early onset sepsis in the present study. Other authors showed high prevalence of Gram-negative septicemia in babies weighing less than 2 Kg.[6],[4],[10] Similar findings have been observed in the present study. Neonatal sepsis occurs in 1 to 8 babies per 1000 livebirths but is 25 times more likely in very low birth weight infants (<1500g) and 50-75 times more likely in extremely low birth weight infants (500-1000g).[11]
The most common bacteria isolated from blood culture in the present study was Klebsiella-Spp . This is similar to the observation from neonatal-perinatal database (NNF 1999). The data from neonatal-perinatal database (NNF 1999) showed Staphylococcus aureus as second most common organism followed by Esch coli and Pseudomonas-Spp . Similar results were observed in a previous study from our hospital.[12]
The surface culture of babies excluding umbilical swab like throat, external auditory canal and gastric aspirate culture correlated significantly with blood culture. The correlation between the maternal genital bacteria and blood culture was not significant. The correlation between umbilical swab culture, ear swab culture, throat culture and gastric aspirate culture with maternal genital bacteria was significant. In an earlier study involving 109 mothers and their babies, four babies had developed early onset sepsis with colonization of throat with Klebsiella-Spp .[13] In the present study, there was definite correlation between surface culture and blood culture of babies. The risk for sepsis world increase if there was superficial colonization with pathogenic bacteria. Pathogenic bacteria were isolated from the genital tract of 28 mothers whose babies had sepsis.[14] However, rarely organism with similar identity and antibiogram to that isolated from the blood culture of the baby were obtained from the mother. But, mothers of blood culture positive babies showed high carriage rates of Esch coli and Klebsiella . Maternal genital colonization with Esch coli was seen in higher proportion when the babies developed early onset sepsis. But the most common bacteria isolated from blood were Klebsiella and not Esch coli . This may be explained on the basis of higher virulence of Klebsiella strains in our population and needs further investigation to identify additional risk factors.
Key message
Surface colonizing bacteria are important in early onset sepsis.
Although genital tract colonization is common among the mothers of babies with sepsis, the type of bacteria isolated from baby's blood are different.
Contribution of Authors
BM conducted the study and drafted the script, VB guided for proper conduction of study, BH & SH involved in collection of samples and isolation of bacteria, UC helped in statistical analysis
References
1. Klein J, Marcy M. Bacterial sepsis and meningitis. In Remington J, Klein J eds. Infectious Diseases of the Fetus and Newborn Infant, Ed 4. Philadelphia, WB Saunders, 1995; 835-890.
2. Beargie R, Priscilla L, Elon T, John D. Perinatal infection and vaginal flora. Am J Obstet Gynecol 1975; 122 : 31-33.
3. Rao k, Ramji S, Thirupuram S, Prakash K. Clinical and bacteriological study of normal and inflamed neonatal conjunctivae. Indian Pediatr 1992; 29 : 161-165.
4. Bhakoo ON, Agarwal KC, Mahajan MC, Walia BN. Septicemia in infants and children: A bacteriological study. Indian Pediatr 1968; 5 : 518-523.
5. Choudhary P , Srivastava G, Agarwal DS, Saini L, Gupta S. Bacteriological study of neonatal infections. Indian Pediatr 1975; 11 : 519-528.
6. Mishra JN, Rai MG, Chakraborthy S, Prasad S. Study of neonatal septicemia. Indian. Pediatr 1985; 22 : 281-285.
7. Grace GM, Nordin T, Myers M. Infections acquired by young infants. Am J Dis Child 1981; 135 : 693-695.
8. Smith RT, Platou ES. Septicemia of new born. Pediatric 1956; 17: 549-553.
9. Schuchat A, Zywicki SS, Dinsmoor MJ. Risk Factors and Opportunities for Prevention of early-onset Neonatal Sepsis: A multicenter Case-Control Study. Pediatric 2000; 105 : 21-26.
10. Jefrerry H, Buth, Metchison, Wigleewert, Pamela JS, Davious A. Early neonatal bacteremia, comparison of Group B Streptococcal, other gram positive and gram negative infection. Arch Dis Child 1977; 52 : 683-685.
11. Mehrotra N, Kumar A, Chansoria M, Kaul K. Neonatal sepsis: correlation of maternal and Neonatal factors to positive bacterial cultures. Indian Pediatr 1985; 22 : 275-280.
12. Bhat BV, Pandey KK, Maya R, Reba K. Bacteriological profile of blood culture isolation from neonates. Indian J Maternal Child Health 1994; 5:114-116.
13. Kishore K, Deorari AK, Meharban singh, Bhujwala RA. Early onset neonatal sepsis -vertical transmission from maternal genital tract. Indian Pediatr 1987; 24 : 45-48.
14. Nathoo KJ, Mason PR, Chimbira TH. Neonatal septicemia in Harare Hospital: etiology and risk factors. The Puerperal Sepsis Study Group. Cent Afr J Med 1990; 36 : 150-156.(Kerur Basavaraj M, Vishnu)
2 Department of Microbiology,Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry., India
3 Department of Obst and Gyanecology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry., India
Abstract
Objective : The study was intended to evaluate the role of maternal genital bacteria and baby's surface colonization in early onset neonatal sepsis. Methods : Babies (born in the hospital of Jawaharlal Institute of Postgraduate Medical Education and Research) who developed clinical signs of sepsis were studied. Swabs were collected for culture from baby's umbilicus, ear, throat in addition to gastric aspirate and blood culture. The genital tract of the mother was also studied for bacterial colonization. The organisms isolated from the maternal genital tract and baby's surface colonization were correlated with those isolated from blood culture by calculating Phi correlation coefficient. Results : Esch coli was the most common organism isolated from maternal genital tract and surface cultures of babies, but Klebseilla-Spp was the most common organism isolated from blood. There was a significant correlation between surface colonization of babies and maternal genital bacteria, so also was baby's surface culture and blood culture. However, correlation between maternal genital bacteria and baby's blood culture was not significant. Conclusion: Surface colonizing bacteria and not maternal genital bacteria are important in early onset neonatal sepsis.
Keywords: Neonatal sepsis; Surface colonization; Maternal genital bacteria
Neonatal sepsis continues to be one of the leading causes of neonatal mortality in India, although its incidence in the west has shown a steady decline.[1] Early onset neonatal sepsis is commonly caused by microorganisms acquired from the mother before or during birth (vertically transmitted and perinatally acquired). Infections presenting after 7 days of birth are considered late onset infections and are generally caused by microorganisms acquired from the environment rather than from the mother (nosocomial and horizontally transmitted). Maternal genital tract organisms may play an important role in early onset sepsis, while environmental organisms have a vital role in late onset sepsis.[1] However, the demarcation is not very discrete. Neonatal risk factors for invasive bacterial disease and its diagnosis and therapy remain an important problem for obstetricians and pediatricians alike. The present study was conducted to find out the correlation between maternal genital bacteria, baby's surface colonization and neonatal sepsis.
Materials and methods
The present study involved 102 babies born in JIPMER hospital and were treated with antibiotics for clinical evidence of sepsis and positive screening test. A detailed history was obtained which included antenatal care, treatment received in other hospital, maternal fever within one week of delivery, history suggestive of urinary tract infection, any medical illness, anemia, history suggestive of intrauterine infection, quality of liquor, duration of labor, mode of delivery, Apgar score of babies and mode of resuscitation.
Gastric aspirate, swabs from throat, umbilicus, external auditory canal and skin of babies were obtained for culture studies. Blood samples were collected for septic screen and culture before starting antibiotics. Cerebrospinal fluid, urine and other appropriate body fluids were collected as and when indicated. Specimens obtained for culture were immediately plated on Mac-Conkey and blood agar for aerobic bacterial culture. Septic screening included total count, differential count, band cell count, micro ESR, and qualitative estimation of C reactive protein (CRP) by latex particle agglutination. Band cell count was considered as positive when percentage of band cells was more than 20% of total neutrophil count. Micro ESR was considered as positive when it was more than 15 mm or 3 mm above the age in days during the first hour. CRP estimation was done using "MEDI CRP" (Medicare diagnostics), which is a slide based latex assay for CRP.
High vaginal swabs were taken from mothers of these babies after informed consent Mother's hemoglobin and total leukocyte count were also obtained. Type of bacteria isolated from mother's genital tract and their antibiotic sensitivity pattern was studied. The babies received supportive care and antibiotic therapy as per our unit protocol. They were followed up till discharge. Organisms isolated from the baby and mother was correlated by calculating Phi correlation coefficient.
Results
Among 102 cases of early onset sepsis in the present study, 21 (20%) cases were found with positive blood culture. Neonatal surface colonization occurred in 37% and 24% cases due to Esch. coli and Klebsiella-Spp respectively in the present study. PROM for mothers was an important risk factor in early onset neonatal sepsis. In the present study 90.2% of the mothers had PROM of more than 12 hours and 70.6% had PROM for 12-24 hours. 83.4% babies with sepsis were preterm, 79.4% babies were between 30 to 36 weeks.
The most common symptom in early onset neonatal sepsis was respiratory distress followed by poor activity. Among Septic screen tests, micro ESR appeared to be the most sensitive test as it was positive in 93 % of cases with early onset sepsis, followed by CRP which was positive in 82.4%. Band count was positive in 63.7% of cases.
Maternal genital canal colonization was seen in 52 cases with early onset neonatal sepsis. Esch coli was the most common isolate followed by Klebsiella species. Group B streptococcus was observed in only one case. Multiple species of bacteria were seen in some mothers. The most common combination was that of Esch. coli with Klebsiella species table1.
Klebsiella-Spp was the most common bacteria isolated from blood culture in the present study, Klebsiella-Spp followed by Esch coli , Acinetobacter and Coagulase negative Staphylococci. Group B Streptococcus was isolated only in one case table1. Four babies in the present study expired and all of them had meningitis. Klebseilla-Spp was isolated from blood and cerebrospinal fluid in two of them.
There was a significant correlation between maternal genital tract bacteria and baby's surface colonization table2. Baby's surface colonization also had significant correlation with organism isolated from baby's blood. However, maternal genital bacteria did not have significant correlation with bacteria isolated from blood culture table3.
Discussion
The most common organism isolated from maternal genital tract was Esch coli followed by Klebsiella-Spp . But in western countries Gr B streptococcily BS was the most common organism implicated in maternal genital tract colonization.[2] In a study from Delhi the most common organism isolated from maternal genital tract was Esch. coli followed by Staphylococcus aureus and Klebsiella-Spp .[3] The variation of bacteria isolated from genital tract may represent regional variation of genital flora.
Respiratory distress was the most common symptom in the babies with sepsis, followed by poor activity and sclerema; similar observations were made by others.[4],[5] Mishra et al recorded 3.3% meningitis among babies with sepsis, while other authors have quoted incidence varying from 3% to 8%.[4],[5],[6],[7] Much higher incidence of meningitis i.e., 25% was recorded by others.[8] The incidence of meningitis appears to be decreasing now probably because of early intervention and higher antibiotics available at present.
Maternal fever also seemed to be an important risk factor as 49% babies in the present study were born to mothers with history of fever. An obstetric risk factor, intrapartum fever, or membrane rupture of 18 hours more were found in 49% of GBS cases and 79% of other sepsis in a case control study of early onset neonatal sepsis[9].The incidence of positive blood and superficial cultures increased significantly when the membranes ruptured for 24 hours or more prior to delivery. There was a three-fold increase in the incidence of sepsis when membranes ruptured for 24 hours prior to delivery.
Low birth weight and prematurity are important risk factors in early onset sepsis in the present study. Other authors showed high prevalence of Gram-negative septicemia in babies weighing less than 2 Kg.[6],[4],[10] Similar findings have been observed in the present study. Neonatal sepsis occurs in 1 to 8 babies per 1000 livebirths but is 25 times more likely in very low birth weight infants (<1500g) and 50-75 times more likely in extremely low birth weight infants (500-1000g).[11]
The most common bacteria isolated from blood culture in the present study was Klebsiella-Spp . This is similar to the observation from neonatal-perinatal database (NNF 1999). The data from neonatal-perinatal database (NNF 1999) showed Staphylococcus aureus as second most common organism followed by Esch coli and Pseudomonas-Spp . Similar results were observed in a previous study from our hospital.[12]
The surface culture of babies excluding umbilical swab like throat, external auditory canal and gastric aspirate culture correlated significantly with blood culture. The correlation between the maternal genital bacteria and blood culture was not significant. The correlation between umbilical swab culture, ear swab culture, throat culture and gastric aspirate culture with maternal genital bacteria was significant. In an earlier study involving 109 mothers and their babies, four babies had developed early onset sepsis with colonization of throat with Klebsiella-Spp .[13] In the present study, there was definite correlation between surface culture and blood culture of babies. The risk for sepsis world increase if there was superficial colonization with pathogenic bacteria. Pathogenic bacteria were isolated from the genital tract of 28 mothers whose babies had sepsis.[14] However, rarely organism with similar identity and antibiogram to that isolated from the blood culture of the baby were obtained from the mother. But, mothers of blood culture positive babies showed high carriage rates of Esch coli and Klebsiella . Maternal genital colonization with Esch coli was seen in higher proportion when the babies developed early onset sepsis. But the most common bacteria isolated from blood were Klebsiella and not Esch coli . This may be explained on the basis of higher virulence of Klebsiella strains in our population and needs further investigation to identify additional risk factors.
Key message
Surface colonizing bacteria are important in early onset sepsis.
Although genital tract colonization is common among the mothers of babies with sepsis, the type of bacteria isolated from baby's blood are different.
Contribution of Authors
BM conducted the study and drafted the script, VB guided for proper conduction of study, BH & SH involved in collection of samples and isolation of bacteria, UC helped in statistical analysis
References
1. Klein J, Marcy M. Bacterial sepsis and meningitis. In Remington J, Klein J eds. Infectious Diseases of the Fetus and Newborn Infant, Ed 4. Philadelphia, WB Saunders, 1995; 835-890.
2. Beargie R, Priscilla L, Elon T, John D. Perinatal infection and vaginal flora. Am J Obstet Gynecol 1975; 122 : 31-33.
3. Rao k, Ramji S, Thirupuram S, Prakash K. Clinical and bacteriological study of normal and inflamed neonatal conjunctivae. Indian Pediatr 1992; 29 : 161-165.
4. Bhakoo ON, Agarwal KC, Mahajan MC, Walia BN. Septicemia in infants and children: A bacteriological study. Indian Pediatr 1968; 5 : 518-523.
5. Choudhary P , Srivastava G, Agarwal DS, Saini L, Gupta S. Bacteriological study of neonatal infections. Indian Pediatr 1975; 11 : 519-528.
6. Mishra JN, Rai MG, Chakraborthy S, Prasad S. Study of neonatal septicemia. Indian. Pediatr 1985; 22 : 281-285.
7. Grace GM, Nordin T, Myers M. Infections acquired by young infants. Am J Dis Child 1981; 135 : 693-695.
8. Smith RT, Platou ES. Septicemia of new born. Pediatric 1956; 17: 549-553.
9. Schuchat A, Zywicki SS, Dinsmoor MJ. Risk Factors and Opportunities for Prevention of early-onset Neonatal Sepsis: A multicenter Case-Control Study. Pediatric 2000; 105 : 21-26.
10. Jefrerry H, Buth, Metchison, Wigleewert, Pamela JS, Davious A. Early neonatal bacteremia, comparison of Group B Streptococcal, other gram positive and gram negative infection. Arch Dis Child 1977; 52 : 683-685.
11. Mehrotra N, Kumar A, Chansoria M, Kaul K. Neonatal sepsis: correlation of maternal and Neonatal factors to positive bacterial cultures. Indian Pediatr 1985; 22 : 275-280.
12. Bhat BV, Pandey KK, Maya R, Reba K. Bacteriological profile of blood culture isolation from neonates. Indian J Maternal Child Health 1994; 5:114-116.
13. Kishore K, Deorari AK, Meharban singh, Bhujwala RA. Early onset neonatal sepsis -vertical transmission from maternal genital tract. Indian Pediatr 1987; 24 : 45-48.
14. Nathoo KJ, Mason PR, Chimbira TH. Neonatal septicemia in Harare Hospital: etiology and risk factors. The Puerperal Sepsis Study Group. Cent Afr J Med 1990; 36 : 150-156.(Kerur Basavaraj M, Vishnu)