| Abstract|| |
Background: Various factors predispose to neonatal septicemia (NS) and study of these factors and a change in bacterial spectrum and antimicrobial susceptibility pattern was noticed in this study, which will certainly help in treatment of septicemic neonates. Objective: To isolate the causative agents of NS, antimicrobial susceptibility pattern of the isolates and to analyze the various predisposing factors to NS. Materials and Methods: Study was done over a period of two years. Blood samples from 200 clinically suspected NS cases were subjected to aerobic culture and their antimicrobial susceptibility pattern was determined. History of sex, gestational age, birth weight, term or preterm, outborn, or inborn babies were taken. Results: Of 200 cases, 95 (47.5%) were blood culture positive. Of them, 64 (67.37%) were males, 64 (67.37%) were preterm, birth weight <1.5 kg were 41 (43.16%), 71.58% outborn neonates with 55.79% mortality rate. Gram-negative isolates were 67 (70.53%) and Gram-positive isolates were 28 (29.47%). Enterobacter cloacae and Staphylococcus aureus were commonest isolates in 20% and 11.58% of cases, respectively. Gram-negative isolates were sensitive to amikacin, ciprofloxacin, and ofloxacin and least sensitive to ampicillin and amoxiclav. All Gram-positive isolates were sensitive to vancomycin. Conclusion: NS was found to be 47.5% in our study. In this study, we have analyzed various predisposing factors of NS. Blood culture is the gold standard for diagnosis of NS. A change in bacterial spectrum and change in their antimicrobial susceptibility pattern was noticed in this study, which will certainly help in treating such cases.
Keywords: Antimicrobial Susceptibility Test, Blood Culture, Changing Bacterial Spectrum, Neonatal Septicemia
|How to cite this article:|
Rajendraprasad BM, Basavaraj KN, Antony B. Bacterial spectrum of neonatal septicemia with their antibiogram with reference to various predisposing factors in a tertiary care hospital in Southern India. Ann Trop Med Public Health 2013;6:96-9
|How to cite this URL:|
Rajendraprasad BM, Basavaraj KN, Antony B. Bacterial spectrum of neonatal septicemia with their antibiogram with reference to various predisposing factors in a tertiary care hospital in Southern India. Ann Trop Med Public Health [serial online] 2013 [cited 2020 Apr 7];6:96-9. Available from: http://www.atmph.org/text.asp?2013/6/1/96/115204
| Introduction|| |
Neonatal septicemia (NS) is a clinical syndrome characterized by systemic signs of infection and accompanied by bacteremia in the first month of life. In developing countries, one of the leading factors for neonatal morbidity and mortality is bacterial sepsis. In India, this continues to be cause of neonatal deaths next only to perinatal asphyxia and birth injuries. Septicemia was commonest clinical category with an incidence of 23/1 000 live births.  It is common in preterm and low birth weight babies. Hence, it is quite essential that every sick neonate should be examined to rule out septicemia.  The studies show that incidence of NS varies from 7.1 to 38/1 000 live births in Asia  and from India 0.1% to 4.5%. 
The various factors like sex, gestational age, birth weight, outborn or inborn status of babies predispose to NS. The gold standard for the diagnosis of NS is a positive blood culture.  Knowledge of changing pattern of bacterial spectrum and antimicrobial resistance will be great value in treating this clinical entity.
The present study was undertaken to analyze various predisposing factors of bacterial sepsis, to isolate the responsible organisms from blood and to determine their antimicrobial susceptibility pattern, which is of great clinical importance in treating NS cases.
| Materials and Methods|| |
The present study was conducted at department of Microbiology, Sri Siddartha Medical College and Research Centre, a tertiary care hospital near Bangalore, Southern India, over a period of 2 years. Ethical clearance was taken from the institutional ethical committee. The study group comprised of clinically suspected 200 cases in the neonatal intensive care unit. History of sex, gestational age, birth weight, term or preterm, outborn or inborn status, whether the baby survived or died were taken.
One ml each of blood samples were drawn from two different sites by peripheral venipuncture taking all aseptic precautions and added to separate bottles of 10 ml brain heart infusion broth with liquoid. Blood culture bottle were incubated at 37°C overnight. Subcultures were done after 24 hours of incubation on to blood agar, MacConkey agar, and chocolate agar. If no growth occurred on plates, subsequent subcultures were done on days 2 nd , 3 rd , and 7 th day. Identification of the isolate was done by studying colony morphology, Gram stain, motility and biochemical test like carbohydrates fermentation, IMViC tests, H 2 S production, oxidase test and catalase test. Group B Streptococci were identified by CAMP test, hippurate hydrolysis, and coagglutination test. Listeria monocytogenes was identified by colony morphology, characteristic motility, and biochemical test like carbohydrates fermentation and esculin hydrolysis. ,
Antimicrobial susceptibility testing of isolates was done on Muller-Hinton agar by Kirby-Bauer disc diffusion method with antibiotic discs obtained from Hi-media Pvt. Ltd., Mumbai, according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. 
| Results|| |
In 95 cases whose cultures were positive, male babies were more 64 (67.37%) compared to females 31 (32.63%) and 64 (67.37%) were preterm babies compared to term babies 31 (32.63%). Babies with birth weight <1.5 kg were 41 (43.16%), whereas babies with birth weight 1.5 to 2.5 kg were 32.63% and lesser for >2.5kgs were 23 (24.21%). 68 (71.58%) were outborn and 27 (28.42%) were inborn babies. The survival rate among the culture-proven cases was 44.21% (42 cases survived) and death rate was 55.79% (53 babies died).
[Table 1]: Total 200 cases of clinically suspected septicemia, 95 cases were blood culture positive. Thus, prevalence of NS in the present study was 47.5%.
Gram-negative organisms were predominant with 67 isolates (70.53%). Enterobacter cloacae 19 (20%) and Klebsiella pneumoniae 16 (16.84%) were the common isolates. Among the Gram-positive isolates 28 (29.47%), Staphylococcus aureus 11 (11.58%) and Coagulase negative Staphylococci (CoNS) 10 (10.53%) were the predominant isolates. The unusual isolates include Group B Streptococci 3 (3.16%) from three cases and Listeria monocytogenes from one case.
[Table 2]: The antimicrobial susceptibility pattern of the isolates revealed that all the strains of Enterobacter cloacae were resistant to penicillins and cephalosporins but sensitive to fluoroquinolones. Other organisms showed variable activity to different antimicrobial agents. Amikacin was found to be very effective (75-100% sensitivity) except for Citrobacter koseri (60%) and Pseudomonas aeruginosa (40%). All the Gram-positive isolates were sensitive to vancomycin.
|Table 2: Antimicrobial susceptibility pattern of Gram-negative bacterial isolates|
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| Discussion|| |
Review of literature has shown that the incidence of NS varied from 18.8%  to 64.87%.  In our study, prevalence rate was found to be 47.5% which is in accordance with earlier reports.
Evaluation of predisposing factors contributing toward NS, like sex, gestational age, birth weight, outborn or inborn babies, were studied. Male babies were predominantly involved in NS (61.8%) than females (38.2%) as reported.  In this study, percentage of males affected was higher (67.37%) compared to females (32.63%). This could be explained on the basis of genetic factors. The usual predominance of male in NS could be linked to the sex factor making them more susceptible. Few Indian studies reported that preterm babies are at higher risk of sepsis. , In our study also, preterm babies are more involved 64 (67.37%) than term babies 31 (32.63%). This may be attributed to immaturity of immune system in preterm babies than term babies.
The risk for infection was more in babies weighing less than 2000g and very low birth weight babies were reported. , In the present study also, the percentage of babies suffering from NS with birth weight <1.5 kg were 41 (43.16%), whereas with birth weight 1.5-2.5 kg were 32.63% and lesser for >2.5 kg were 23 (24.21%). A study showed that septicemia among outborn was 34% and inborn babies was 32%.  Our study showed that 68 (71.58%) outborn babies and 27 (28.42%) inborn babies showed septicemia pointing out a community acquired source. Reports of mortality rate of NS varies from 14.4% to 23%. , In the present study, mortality rate was 55.79% in culture-positive cases.
A change in bacteriological spectrum has been noticed from time to time. In earlier studies, predominant Gram-negative organism was Klebsiella species with an isolation rate of 24.6% to 42.2%. ,, In our study, 16 strains of Klebsiella pneumoniae were isolated next to Enterobacter cloacae. The prevalence of Enterobacter cloacae was noticed in our study, 19 of the 67 Gram-negative isolates (28.35%). Enterobacter cloacae may be acquiring more clinical significance by replacing other Gram-negative organisms in neonatal intensive care units. ,, Role of Citrobacter freundii (17.07%) and Citrobacter diversus (2.43%) in neonatal sepsis was reported.  Comparatively, 11.58% of Citrobacter freundii and 5.26% of Citrobacter koseri were isolated in this study. Sepsis due to Pseudomonas aeruginosa was 5.26% and Acinetobacter was 2.11% in our cases.
Few workers noticed the prevalence of Staphylococcus in NS. , We isolated 11 strains of Staphylococcus aureus and 10 CoNS in the study. Three strains of Enterococci and other unusual isolates include three strains of Group B Streptococci and one case of Listeria monocytogenes.
Due to the emergence of resistant strains as a result of indiscriminate use of antibiotics, antibiogram varies from time to time and from one institution to another. In the present study, all strains of Enterobacter cloacae, the predominant isolates was sensitive to ciprofloxacin, ofloxacin, sparfloxacin, 94.74% sensitive to amikacin and resistant to cephalosporins and amoxiclav. Other strains showed variable susceptibility patterns. Amikacin was drug of choice in our study. All the Gram-positive isolates were sensitive to vancomycin.
Blood culture is still the "Gold standard" for the diagnosis of septicemia in neonates and should be done in all cases of suspected septicemia. In view of the changing spectrum of the causative agents of NS and their antimicrobial susceptibility patterns, a positive blood culture and the antimicrobial susceptibility testing of the isolates are the best guide in choosing the appropriate antimicrobial therapy in treating NS.
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Bheemasamudra Patel Mallikarjunappa Rajendraprasad
Professor, J.J.M. Medical College, Davangere, Karnataka
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2]