Bacteriological Profile and Antibiotic Sensitivity Pattern of Neonatal Sepsis in Central Paediatric Referral Hospital in Nepal

Introduction: Neonatal sepsis is the most common cause of neonatal morbidity and mortality. The causative organisms of neonatal sepsis are changing and so do their antibiotic sensitivity pattern. So it is important to regularly monitor the change in bacteriological profile and their antimicrobial sensitivity pattern to help update the treatment guidelines of neonates. This study aimed to study the microbiological patterns of neonatal sepsis and their antibiotic susceptibility pattern in a tertiary care centre in Kathmandu. Methods: A prospective study was carried out among cases of neonatal sepsis admitted in Neonatal Intermediate Care Unit (NIMCU) of a tertiary care referral hospital from August 2015 to August 2016. Prospective data were collected with pretested and standardised proforma and analysed using SPSS version 20. Results: Out of 311 neonates admitted over a period of one year with diagnosis of neonatal sepsis, male:female ratio was 2.1:1. Among them 234 (75.2%) cases were of LONS and 77 (24.8%) were of EONS. Blood culture was positive in 47 neonates (15.1%). The organisms isolated included staphylococcus aureus (34.0%), klebsiella (32%), CONS (24%), escherechia coli (6%) and enterobacter (4%). In LOS, gram positive organisms staphylococcus and CONS were the commonest ones (61.4%). In EOS, gram negative organism klebsiella (65%) was more common. Most of staph aureus were susceptible to penicillins, amikacin and cefotaxime. Klebsiella was found to be resistant to penicillins, amikacin and cefotaxime. Conclusion: There is possible increasing incidence of gram positive septicemia in LONS and increasing emergence of resistance of kleibsella to the common antibiotics ampicillin, amikacin and cefotaxime.


INTRODUCTION
Neonatal sepsis is one of the major causes of morbidity and mortality among the newborns in the developing world. 1 Neonatal infection currently causes about 1.6 million deaths per year in developing countries. It is estimated that 26% of the newborns who die do so as a result of infections that occur around birth. 2 Early onset sepsis (EOS) refers to infections during the first 72 hours of life that is usually related to intrapartum transmission from mothers; whereas late onset sepsis (LOS) refers to postnatal acquisition of infections after the first three days of life. 3 Pathogens encountered in neonatal sepsis vary worldwide; reports from developing countries more commonly show Gram negative organisms 4,5 although gram positive organisms have been also reported. These organisms have developed multidrug resistance over the last two decades. 6 The reasons for this resistance are indiscriminate and irrational use of antibiotics, over the counter sale of antibiotics and ineffective infection control in maternity centres. 7 This has currently lead to frequent use of second and third line antibiotics frequently in our institute.
The local epidemiological pattern of sepsis can be variable and this pattern can change with time. 8 Timely microbiological surveillance and assessment of antimicrobial resistance is a key component in decreasing the rate of neonatal sepsis and the associated mortality. 9 Thus regular monitoring and updates on the causes of neonatal sepsis and the antimicrobial sensitivity pattern is important for effective treatment and prevention of neonatal sepsis.
Therefore, in this current study, investigators aimed to describe the microbiological patterns and the antibiotic susceptibility pattern of the organisms isolated in blood culture in cases of neonatal sepsis in a tertiary care centre in Kathmandu.

METHODS
This is a prospective study done in tertiary care referral centre in Kathmandu, Nepal from August 2015 to August 2016 with pre approval from Ethical Committee of the hospital. All the cases of neonatal sepsis admitted in the hospital were included in the study. Infants were classified into two groups according to the timing of sepsis diagnosis: EOS diagnosed ≤ 72 hours of life and LOS diagnosed > 72 hours of life. Demographic, clinical, and laboratory data were retrieved for all included infants. Blood culture reports and antibiotic sensitivity were studied. Data were collected and analysed using SPSS 20.

RESULTS
Total of 311 neonates were admitted in the hospital over a period of one year with the diagnosis of neonatal sepsis (NNS). There were 211 male neonates (67.8%) and 100 female neonates (32.2%) with male:female Ratio of 2.1:1. Among them 234 (75.2%) cases were of LOS and 77 (24.8%) were of EOS. Most of the cases of NNS were found in term infants (92.6%) and in appropriate for gestational age group (77.2%).
Out of 311 neonates, blood culture was positive in 47 neonates (15.1%). In EOS, eight (10.3%) neonates had organism isolated in blood culture whereas in LOS, 39 (16.6%) had culture positivity. The organisms isolated included staphylococcus aureus in 16 cases, klebsiella in 15 cases, CONS in 11 cases, Escherichia coli in three and enterobacter in two cases.
In LOS, gram positive organisms, staphylococcus and CONS were isolated in 61.4% cases. In EOS, gram negative organism Klebsiella (65%) was more common followed by staph aureus (35%).    10,11,16,17 The variation on these values could be because of differences in the lab resource and facilities. Furthermore it is also influenced by the practice of using antibiotics prior to the hospital arrival.

DISCUSSION
Organisms were isolated more in LOS (16.6%) than EOS (10.3%) though there is no statistical significance. Overall, Staphylococcus aureus is the commonest organism isolated followed by Klebsiella, CONS, E. Coli and Enterobacter. Similar results were found in the study done in Nepal, Nigeria and Gondar where gram positive organisms predominated the isolates. 8,16,18 This is in contrast to other studies where gm negative organisms were predominant in causing neonatal sepsis. 11,17 The most noteworthy changes observed are the studies done in this same institute during various times. The study done by Shrestha NJ et al. in 2008-2009 demonstrated E. Coli as the most common organism followed by staph aureus. 10 But in study done in 2014-2015 by Chapagain RH et al. in the same institute showed Staph aureus as the main cause of NNS followed by CONS. This might reflect the changing pattern of the organisms of neonatal sepsis over time though conclusion cannot be made based on this few samples. It has been shown that horizontal transmission from mothers is probably the major source of Staphylococcus aureus to neonates. 19 This observation may therefore suggest poor hygiene as a major contributing factor to the high incidence of NNS in developing countries. It is also possible that the n a s a l a n d / o r v a g i n a l c a r r i a g e r a t  20 Similarly CONS was found to be sensitive to cloxacillin, ciprofloxacin and amikacin whereas two were resistant to cefotaxime and one was found to be resistant to amikacin.
The most remarkable resistance was observed with Klebsiella. Many of the times, it showed resistance to ampicillin, amikacin and cefotaxime which are most often used for the treatment of neonatal sepsis in our hospital. They were found to be sensitive to ceftazidime, cefipime and imipenem. Similar resistance pattern of gram negative organisms were observed in the study done in Pakistan. 15

CONCLUSIONS
Pathogens for neonatal sepsis can change over time, so do their sensitivity pattern. This study suggests that gram positive organisms are becoming more dominant cause of neonatal sepsis and gram negative organisms are becoming more resistant to the common drugs used for treatment of NNS. Every institute should regularly monitor the microbiological profile with their sensitivity pattern of NNS that helps update the neonatal sepsis guideline for effective management of NNS.