Mir Sumsam Ali Khurram
A comparative study of CBP, CRP, Micro ESR and blood culture in the diagnosis of neonatal septicemia

Mir Sumsam Ali Khurram1, Naseem A2, Prasad C.N. D3

1Dr. Mir Sumsam Ali Khurram, Associate Professor, Department of Pediatrics, Deccan College of Medical Sciences, Hyderabad, Telangana State, India, 2Dr. Altaf Naseem, Professor Department of Pediatric, Deccan College of Medical Sciences, Hyderabad, Telangana State, India, 3Dr. C. N. Prasad, Professor & Head of the Department of Pediatric Surgery,  Deccan College of Medical Sciences,  Hyderabad, Telangana State, India.

Address for Corresponence: Dr. Mir Sumsam Ali Khurram, Associate Professor, Department of Pediatrics, Deccan College of Medical Sciences, Hyderabad, Telangana State, India. E-mail: dr.sakhurram@gmail.com



Abstract

Background: Neonatal sepsis is one of the most important causes of morbidity and mortality in children. The incidence was 3% in intramural births, with an overallmortality rate of variation of 18.6%. Aims and Objectives: To evaluate the role of blood culture, micro ESR, CBP, CRP in the diagnosis of sepsis in children. To study sensitivity, specificity, positive predictive values and negative predictive values of the above hematological parameters, either individually or in combination with diagnosis of neonatal sepsis. Method: A study was carried out from January 2015 to December 2015  in hospital, based  on, samples of babies with   history of infective etiology  within the first 28 days of birth. Result: One hundred neonatal cases of clinically suspected septicemia were studied. Culture positive rate was 26%. E coli was the major organism responsible for early onset of sepsis. The highest sensitivity and negative predictive value was found for septic score of more than or equal to 3 by septic scoring, I:T ratio and C- reactive protein with the highest sensitivity, micro ESR and TLC with  the highest specificity. Conclusion: CRP emerged as the test with the highest sensitivity. Micro- ESR and TLC had the highest specificity.

Keywords: Neonatal sepsis, Blood culture, C- reactive protein, Micro ESR



Manuscript received: 28th May 2016 , Reviewed: 12th June 2016
Author Corrected; 26th June 2016, Accepted for Publication: 10th July 2016

Introduction

Neonatal sepsis in neonates is a clinical syndrome characterized by systemic sign of infection accompanied by bacteremia in the first 28 days of birth [1]. Neonatal sepsis is a complex syndrome caused by an uncontrolled systemic inflammatory response of infectious origin characterized by multiple manifestations which can result in dysfunction and failure of one or more organs and even death [2]. Neonatal sepsis is one of the most important, commonest and major causes of morbidity and mortality. The incidence was 3% among the intramural births, with an overall mortality rate variation of 18.6% [3]. Among the extramural ad mission, sepsis was responsible for 39.7%; on the other hand, indiscriminative overuse of antibiotics, was hazardous for any neonatal unit which may lead to overtreatment and emergence of resistant organism [4, 5]. The clinicians focused on diagnostic test which has high sensitivity and high negative predictive accuracy. These  are direct or indirect hematological tests [5]. Septic screens are the batteries of parameter studies in order to improve diagnostic accuracy [5]. Of these, leukocyte count and indices of micro ESR and CRP were the most studied tests which were cost efficient. Therefore, a group of tests was studied to access the usefulness either singly or in combination with predicting neonatal sepsis. These tests were of total leucocytecount (TLC), Absolute neutrophil count (ANC) immature total ratio (I:T ratio) platelet count, micro ESR and CRP.

Materials and Methods

Astudy was conducted in the neonatology unit of Princess Esra Hospital attached to Deccan College of Medical Sciences, Hyderabad, Telangana State, India from 1st January 2015 to end of December 2015. In all, 100 neonates were studied. Samples included babies with history of illness of ineffective etiology with the onset within 28 days of birth.

Inclusive  Criteria :  Neonate intramural or extramural delivery, clinically presenting  symptoms  of sepsis on physical examination such as refusal to feed, lethargy, hypothermia, hyperthermia, vomiting, abdominal distension and diarrhea were  studied.

Exclusive Criteria: Neonates with lethal congenital anomalies, extreme low birth weight, respiratory distress syndrome and babies treated previously with antibiotics for more than 12 hours were excluded from this study. Detailed clinical examination of each baby was carried out. Gestational age was also calculated. When illness started in the first 72 hours of birth,it was an early onset of disease and after 72 hours, it was late onset.  Gestational age of babies was assessed using Ballard Scoring system to classify them as preterm, term, and post term. Blood samples were collected from the neonates suspected for septicemia. The study was divided into three groups for analysis as follows; Proven sepsis, probable sepsis, and no sepsis. Proven sepsis was defined as blood culture or CSF culture or culture from other significant site showing positive for any bacterial growth within 48 to 72 hours. Investigation suggested sepsis. 1 ml of blood sample was collected through peripheral venipuncture in a bottle containing Potassium EDTA. It was subjected to platelet count. Total leucocyte count and differential count analysis were shown on automated cell counters. Band forms with less mature cellswere classified as immature polymorpho nuclear leucocytes. I:T ratio was calculated after counting 200 cells. Total leucocytes count, and absolute neutrophil count was recorded .

I : T ratios tested as Monroe’s criteria was for term babies and mouzinho criteria for VLBW babies. 0.5 ml to 1 ml of blood sample was taken for micro ESR and CRP estimation. Venous blood was collected in preheparinized microhemocrit glass tube of 7.5 mm length. More than or equal to 15 mm at the end of first hour was taken as significant. C Reactive protein was done by semi quantitative method using Rhelax CRP kit. A positive agglutination with undiluted serum sample corresponding to CRP concentration of 6 micro g/ml was used to calculate each parameter and combination of parameters. Statistical analysis was done using graph pad prism 5 (Graphpad software, Inc, USA). Data is presented as mean + SD. Variable difference with P<0.05 is considered statistically significant. The sample size was determined by using the open EPI statistics of 95% confidence to detect the result with 90 % of sample power.  
 
Results

One hundred neonates admitted in the neonatal unit, were divided into Group A and Group B. In group A, the neonates were subjected to CBP which included TLC, ANC, I:T ratio, platelet count, micro ESR, CRP, blood culture, and other investigations to support  diagnosis. In group B, all investigations were carried out other than blood culture to support diagnosis. The babies were subjected to sepsis in the first 28 days of birth. The study showed that the group comprised 61 males and 39 females   in the ratio of 1.56:1

Table -1: Hematological Investigation in relation to blood culture

Test

Positive

Negative

 

 

 

Culture

Positive

Culture

Negative

Culture

Positive

Culture

Negative

k

TLC

08

08

05

29

0.40

ANC

10

15

15

10

0.28

I:T Ratio

13

12

00

25

0.52

Platelets

02

09

11

28

0.00

Micro ESR

07

08

06

29

0.30

CRP

11

18

02

19

0.26

2 or more

12

18

01

19

0.30

3 or more

12

09

01

28

0.57


Table- 1: shows that total leucocyte count suggestive of sepsis i.e positive was found in 16 cases. .Of these, 8 cases were bacteriologically positive and of the 34 negative cases, 5 grew organism on culture. I:T ratio of more than 0.2 was found in 25  cases of which 13 were positive bacteriologically whereas,  in 25 negative cases, none  was culture positive. ANC was positive in 25 cases of which 10 were proven. Platelet count was less than 1,50,000 per cu.mm in 11 cases of which 2 cases were culture proven. Micro ESR was significantly increased in 15 cases and it was negative in 35 cases of which 6 grew organism I:Tratio was the most sensitive test. CRP was the second most sensitive test being positive in 29 cases, out of which 11 were bacteriologically proven cases. I:T ratio of   more than 0.2 and CRP more than 0.6 microgram /ml emerged as the  most  sensitive tests, where micro ESR was more than 15 mm in first hour. TLC and platelet count for less than 1,50,000/cu mm   was  the  most specific test.  

Table- 2: Accuracy of Hematological Parameters

Test

Total

Positive

Positive with Proven Sepsis

Sn

Sp

PPV

NPV

LR

TLC

16

08

62

78

50

85

 

ANC

25

10

77

59

40

88

 

I:T Ratio

25

13

100

68

52

100

 

Platelets

11

02

15

76

18

72

 

Micro ESR

15

07

54

78

47

78

 

CRP

29

11

85

51

38

90

 

2 or  more test positive

30

12

92

51

40

95

 

3 or more test positive

21

12

92

76

57

96.6

 


Table- 2 Shows that the proven cases of  Sepsis are taken as positive and  other cases are taken as negative. Sensitivity of Septic screen is 92%, Specificity is 51%, PPV is 40% and most importantly 95% of the negative predictive accuracy,

Table- 3: Performance of various combination parameters

Combination of Parameters

Total Positive

Positive with Proven

Sn

Sp

PPV

NPV

Two Test

 

 

 

 

 

 

ANC + I:T Ratio

17

10

77

81

59

91

TLC + PC

3

2

15

97

67

77

I:T Ratio + CRP

23

11

85

68

48

93

Three Test

 

 

 

 

 

 

TLC+PC+ I:T Ratio

3

2

15

97

66

77

ANC + I:T Ration + CRP

15

11

85

89

73

94

I:T Ratio + Micro ESR+ CRP

13

8

62

86

62

86

Four Test

 

 

 

 

 

 

TLC+PC+CRP+ I:T Ratio

3

2

15

97

66

77

Five Test

 

 

 

 

 

 

TLC+ANC+ I:T Ratio + CRP+Micro ESR

7

4

31

92

57

79

TLC+ANC+I:T Ratio+CRP+ Platelets

2

1

08

97

50

75

All Six Test

 

 

 

 

 

 

TLC+ANC+I:T Ratio +CRP+MicroESR+Platelet Count

1

0

00

97

00

73


Table 3: Shows that of the two test combination, I:T ratio+CRP emerged as most sensitive  tests. It identified 11 out of 23 cases of sepsis of 85% out of the two and also a reasonably good specificity of 69%. TLC +PC emerged as the most specific test combination giving specificity of 97%. ANC + I:T ration + CRP were the best in three test combinations with 85% sensitivity and 89% specificity. TLC+PC+I:T ratio produced a specificity of 97%. TLC + I:T ratio + CRP+PC, these four test combinations had a good specificity of 97%. Five and six test combinations identified almost all infants with sepsis.

Discussion

The present study was carried out to study rapid diagnosis of septicemia in newborn babiesupto first month (28days of life) by using some indirect hematological tests with reference to age and dependent neutrophil indices. The prevalence of neonatal sepsis  was 26% which was comparable with the studies of Philip et al [6] and Gerdes et al [5, 6]. Early diagnosis of neonatal sepsis was found to have prevalence of 7.9% and 5.9% respectively which is much lower than what was observed in Singhet al [7] who observed itto be 27.8% in their study. Joshi et al [8] also reported prevalence of 25.8% which was also similar to these studies. In present study, sensitivity, specificity, positive predictive value, negative prediction value of laboratory parameters  were  evaluated in relation to blood culture taken as gold standard.

Table- 4: Total Leucocyte Count (TLC)

Authors (Year)

SN%

SP%

PPV %

NPV %

Philip et al [6]

50

94

40

-

Rodwel  et al [16]

44

92

36

94

Basu et al [18]

12

93

50

32

Present Study

62

78

50

85


In Present study TLC has a sensitivity of 61% comparable to Philip et al (6) {50%} and more than that reported by Rodwel et al [16] (44%). Specificity of 78% observed in the present study was more than that reported by Namdeo et at [17] (69%) and less than that of Mishra et al [13] which is (88%). The positive predictive value of 50% observed in the present study is equivalent to the value reported by Basu et al [18]. High negative predictive value of 85% was observed in the present study which was comparable with observations made by Rodwel et al [16] and Philip et al [6]. The difference of   these studies, when individual predictors of sepsis are considered   varied in positive test criteria. I:T ratio was found to have higher sensitivity of 10% which  is equivalent to Gerdes et al [5] which is (100%) and comparable to Rodwel et al [6] which is  (96%) and Basu et al [18] which is (92%). Philip et al [6]. Mishra et al [13] studied band cell to neutrophil ratio and found to have lower sensitivity as compared with I:T ratio i. e 90% and 92% respectively. Specificity of 68 % observed in the present study was comparable with 71% as observed by Rodwell et al [16] which is (44%). Specificity of 78% observedin the present study was more than that reported by Namdeo  et  al [17] as which is less than that reported by Mishra etal [13] which is  (88%). Positive predictive value of 50% observed in the present study is equivalent to Basu etal [18]. High negative predictive value of 85% observed in the present study was comparable with observation made by Rodwelet al [16] philip et al [6]. I: T ratio was found to have higher sensitivity of 100% which is equivalent to Gerdes et al [5] which is (100%) and comparable to Rodwel et al [16] which is (96%) and Basu et al which is [18] (92%).  Philip et al [6], Mishra et al [13] studied band cells to neutrophil ratio and found to have lower sensitivity as compared with I : T ratio i.e 90% and 92% respectively. Specificity of 68% observed in the present study was comparable with 71% as observed by Rodwel te al [16], which is higher than reported Gerdes et al [5]. Most importantly I:T ratio has got the highest negative predictive value amongst all neutrophils  indices i.e of 100%.

Table-5: Micro ESR

Author (year)

Sn(%)

SPC%

PPYC%

NOVC

Philipe et al [6]

30

97

43

-

Gerdes et al [5]

31

94

24

95

Singh et al [7]

55

81

-

-

Present study

54

78

47

78


to have specificity more than sensitivity, of 78% over 54% reported in the   present study which was comparable with that observed by Singh etal [7] which was 81%, and Gerdes et al [5] which was 94% of specificity, Philip et al [6] was reported 97% of specificity and 30% of sensitivity. Singh et al [7] observed sensitivity of 55% which is comparable with the present study value of 54% of sensitivity.

Table-6: C reactive Protein

Author  (year)

Sn(%)

SPC%

PPYC%

NOVC

Phillipe et al [6]

47

86

22

-

Singh et al [7]

80

91

-

-

Gerdes et al [5]

93

85

28

99

Basu et at [18]

92

68

92

86

Present study

85

51

38

90


CRP was found to have the highest sensitivity in the tests other than neutrophils indices i.e. I:T ratio in the present study. The observation is similar to Singh et al [7] and comparable with Gerdes et al [5] and Basu et al [18]. It has  the  specificity of 51% which is  less than that of Basu et  al [18] High negative predictive value of 90% was found in the study of CRP which is comparable with Basu et al [18] and lower than reported by Gerdes et al [5] . CRP test was a good indicator with high sensitivity and affected by other factors like both  weight, gestational age and onset of disease. In the  present study two or more test positives  had sensitivity of 92%, Specificity of 51%, positive and negative predictive value of 40% and 95% respectively which are comparable with that of Philip etal [6] who showed  the sensitivity of  93%. Specificity-88% and positive predictive value as 39%. These Values were also comparable with 3 of Singh et al [7]  86% of sensitivity and 90%  specificity. Amongst two test combinations I: T ratio + CRP emerged as the most sensitive (85%) and with specificity (68]  and TLC +PC emerged as the  most Specific test with specificity of 97% in  two test combinations. Sharma et al [11], reported CRP + B:N ratio of having sensitivity 100% and specificity 51.7% . Singh et al [7] reported ANC + CRP as the most specific one, whereas Philip et al [6], reported ANC +BN: TN as the most useful combination with highest positive predictive value. Sharma et al [11], reported CRP+ micro ESR + Toxic generation, as the most useful  in  three test combinations with sensitivity of 100% and specificity of 82% which   is  comparable with the  present study. The present study had higher number of low birth weight babies as 80%, out of which 22% were below1500 gm weight. These observations were similar to those reported by Sharma et al [11] (70%), Ahmed et al [10] (60%) and Joshi et al [8]. However, they reported 116 (50.4%) as low birth weight cases in their study.The present study had 60% cases of early onset sepsis while cases with late onset septicemia were 40%. Sharma et al [13] observed 33 cases (66%) of more than 7 days of age.  Incidences of refusal to feed was comparable with Guha et al [7] who observed it to be 66.25% higher than reported by Ahmed et al  [10] (27%) and Waber et al [12] as 41.5%. Lethargy and respiratory distress cases were seen as 80% and 44% respectively in the present study. Guha et al [7] and Sharma et al [11] reported similar incidences of lethargy as 61.25% and 60% cases respectively. Hypothermia was found in 10 cases in the present study, which were preterm babies indicating that hypothermia was more common in preterm babies with septicemia. Chandana et al [14] reported 14% incidences of hyperthermia and 12% incidences of hypothermia.

Abdominal distension and vomiting were seen in 13 and 6 cases respectively whereas diarrhea was found in 9% babies. These findings were similar to those reported by Mishra et al [13]. In the present study, the total leucocyte count sensitivity was 61% comparable with Philip et al 50% and more than that reported by Rodwell et al [16]. Specificity of 78% observed in the present study was more than that reported by Namdeo et al [17] as 69% and less than that of Mishra et al  [13] which   is 88% positive predictive value of 50% observed in the  present study was equivalent to Basu et al  [13]. In the present study, platelet count (<1,50,000/mm3) emerged as the test with good specificity but poor sensitivity. It was found to have specificity of 76% which was comparable with that reported by Mishra et al ([13] 79% and Basu et al [18], as 71%. Micro ESR was found to have specificity more than sensitivity, of 78% over 54% reported in the present study which was comparable with that observed by Singh et al [22] which 81% and Gerdes  et  al [21] which is 94%. In the present study, 100 cases were enrolled on clinical suspicion of sepsis.

Cultural positivity rate was 26% which was similar to that of Singh et  al [ 22] 28% Joshi et al [8] which was 25.8%. In the present study, staphylococcal sp. were the commonest isolates 4/13 along with E coli 4/13 cases followed by klebsiella in 3/13 cases. Blood culture was positive in 12 cases with a blood culture positivity rate of 24%. Ecoli was the commonest organism implicated for early onset sepsis in the present study i.e. 43%. staph sp 50% was the commonest organism responsible for late onset  of sepsis, klebsiella spp 33% and Ecoli 17% were also responsible with 43% cases of early onset of sepsis. In the present study, 23.3% Boo et al [23] was reported  as the highest mortality associated with Klebsiella Sp of 63.8% followed by Ecoli in 57.7%  and staph 27.3%, but in the present study, there was no mortality related to Klebsiella Sp. Ahmed et al [10] studied 30 cases of which 12 cases expired overall mortality and case fatality rate was 28% in the present study. Karthikeyan [24] was observed as case fatality rate of 13.5% which was lower than the present study Joshi et al [8]  observed mortality of 32.2% which was higher than the  present study. Mortality amongst culture positive cases in present study was 31% which was lower as compared with that of Mishra et al [25] who observed mortality of 61.7%. Among gram negative septicemia 71% died whereas mortality was only 49% in gram positive septicemia.
 
Conclusion

Neonatal septicemia is a life threatening emergency Blood culture positive rate was 26%. E.coli was the major organism responsible for early onset of sepsis and staph sp. Was the common culprit for late onset of sepsis. Highest sensitivity and negative predictive values were found for a septic score of more than or equal to 3 by septic scoring. For prevention of neonatal septicemia, it requires to improve survival rate, better approach with early initiation of appropriate antibiotics.

It also requires infection control policies at the national level for effective management of such infections. To define the need for antibiotic therapy, several tests recommended as helpful in diagnosis neonatal sepsis were evaluated.

Funding: Nil, Conflict of interest: Nil    
Permission from IRB: Yes

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How to cite this article?

Mir Sumsam Ali Khurram, Naseem A, Prasad C.N. D.  A comparative study of CBP, CRP, Micro ESR and blood culture in the diagnosis of neonatal septicemia. Int J Pediatr Res.2016;3(7):533-539.doi:10.17511/ijpr.2016.7.12.  


  

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