NEONATAL SEPTICAEMIA: A HOSPITAL BASED STUDY IN EASTERN NEPAL

* B.P. Koirala Institute of Health Sciences, Dharan, Nepal. Address for correspondence : Dr. Basudha Khanal B.P. Koirala Institute of Health Sciences, Dharan, Nepal. Email: basudhak@yahoo.com, basudhak@hotmail.com


INTRODUCTION
Infections remain an important cause of morbidity and mortality in neonates.Neonatal sepsis is the most important of all neonatal infections.Prematurity, immature immune status, inadequate disinfection and sterilization procedures during home delivery are the predisposing factors in neonatal period. 1 A remarkable feature of the clinical manifestation of neonatal septicaemia (NS) is non-specificity of symptoms, which creates difficulty in diagnosis of infection in the early stage.High degree of suspicion and keen observation can help to save the children. 2 Etiological agents implicated in neonatal septicaemia vary from place to place and change with time and antibiotic use.Organisms implicated are dependant on the age of onset of neonatal septicaemia.In early onset (<72Hrs) Group B Streptococcus, Listeria monocytogenes and gram-negative bacilli namely E.coli are commonly involved, whereas coagulase negative Staphylococcus, Enterococcus, Klebsiella and S.aureus predominate in late onset (>72hrs) septicaemia.
Blood culture remains an important investigation in diagnosing NS.But it has its limitations.In routine practice a minimum of 48 hrs are required to isolate, identify and determine the anti-microbial susceptibility pattern of bacteria.Prompt institution of empirical treatment is a necessity to decrease the mortality in the septicaemic neonates.This can be effectively achieved in a hospital set up where a prior knowledge of the organisms causing infection in neonates and their sensitivity pattern is available to the clinician.
The present study was undertaken with the objectives of finding the incidence of neonatal septicaemia and to identify the bacterial pathogens and their antimicrobial susceptibility pattern.

SUBJECTS AND METHODS
The blood culture samples of 1,567 neonates admitted with suspected septicaemia at B.P. Koirala Institute of Health Sciences, a tertiary care teaching hospital in Eastern Nepal, during August 1998 to July 2001 were included in the study.One millilitre of blood collected under aseptic conditions was inoculated in blood culture bottle containing 9 ml of Brain Heart Infusion broth and incubated at 37°C.Subcultures were made on to sheep blood agar, chocolate agar and MacConkey agar after 24 hrs and 48hrs of aerobic incubation.Plates were incubated overnight at 37°C in 5% CO 2 atmosphere.Thereafter, culture bottles were observed for turbidity for 10days.Final subcultures were done before reporting negative.Growth obtained was identified by standard methods. 3ntimicrobial susceptibility of the bacterial isolates to antibiotics namely amikacin, ampicillin, cefotaxime, ciprofloxacin, methicillin and gentamicin was determined by Kirby Bauer's disc diffusion method.Results were interpreted as per NCCLS guidelines.

Patients:
Out of 1,567 blood cultures, 540 (34.5%) were positive for bacterial pathogens.65% were isolated from early onset and 36% were isolated from late onset septicaemia.
While number of total samples remained almost unchanged during the study period, a decrease in the number of positive cultures from 41% and 47% in first and second year to 25% in the third year was observed (Fig. 1).The isolation of Staph aureus remained almost the same during the 3-year period.It was also observed that in 2 nd and 3 rd year of study Klebsiella In a pilot study, carried out in this hospital during 1997-98 in 77 cases of septicaemia, blood culture was found to be positive in 46 (60%) with a predominance of gram-negative bacteria (72%).E.coli being most common followed by Klebsiella, Enterobacter.Staphylococcus aureus was most common among the gram-positive organisms. 4shift in the type of isolates was observed in the present study with a predominance of Staph.aureus(60%).This trend was also observed by other workers. 5,6,7This observation is in contrast to many other studies that reported Klebsiella and other gram-negative organism and Staph.aureus as the common isolates. 8,9,10 the present study, majority of patients had EOS showing predominantly Staph aureus.Being a tertiary care hospital, complicated pregnancies in labour are referred to BPKIHS.Premature rupture of membrane and repeated vaginal examinations by the midwives were the common factors observed on admissions.Staph aureus is not a common organism in the genital tract.Hence it was presumed that possibly due to poor knowledge of disinfection and sterilization in domiciliary practice, or a higher rate of survival of highly susceptible low-birth weight infants, admitted to neonatal intensive care units, acquire this infection from several sources.
Resistance to ampicillin was seen to the tune of 59% in GPC and 68% in GNB, which is in agreement with many other studies.Staph aureus showed resistance (16%) to methicillin an observation also made in other studies. 7,11,12Resistance to other group of antibiotics was in concurrence with other studies.
While the total samples per year remained unaltered, a decrease in the positive culture rates over the three-year period was observed.This is attributed to implementation of infection control measures.A combination of ampicillin and gentamicin is the treatment of choice for NS at BPKIHS.It was observed that Klebsiella were more resistant to gentamicin (69%) than Enterobacter (25%).This could be the possible explanation of relative increase in the incidence of Klebsiella in 2 nd and 3 rd year of the study.
It was concluded that continuous surveillance is needed to understand changing bacterial ecology and the resistance pattern of the antimicrobial agents in a neonatal unit so that an empirical treatment of critically ill or very low birth weight infants could be initiated pending a report of blood culture and sensitivity.Moreover, a decline in infection rate is a great motivation for health care workers for following the infection control practices in the neonatal units.