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|Year : 2002 | Volume : 20 | Issue : 3 | Page : 156-159 |
Bacteriology of neonatal septicaemia in a tertiary care hospital of northern India
I Roy, A Jain, M Kumar, SK Agarwal
Dept. of Paediatrics (MK), King George's Medical College, Lucknow - 226 003, UP, India
Dept. of Paediatrics (MK), King George's Medical College, Lucknow - 226 003, UP, India
To study the bacteriology of neonatal septicaemia in a tertiary care hospital of Northern India we prospectively enrolled all the suspected cases of neonatal septicaemia, which were not on antimicrobials. One to two millilitre of blood from these neonates was cultured in brain heart infusion broth. Out of 728 cases, 346 (47.5%) were positive on blood culture. The most frequent offender was Klebsiella spp. (24.5%) followed by Enterobacter spp. (22.8%). There was an overall predominance of gram negative organisms. Coagulase negative staphylococci (CONS) were more frequently isolated (16.5%) than Staphylococcus aureus (14%). More than 89% of the Staphylococci isolated were resistant to penicillin. None were resistant to vancomycin or teicoplanin. More than 95% of enterobacteria were resistant to anti gram negative penicillin group of drugs and more than 40% were resistant to extended spectrum cephalosporins. Ciprofloxacin and amikacin resistance was infrequent. Thus, initial therapy in our hospital may be aimed at Gram negative organisms and amikacin and ciprofloxacin may be used as first line drugs.
|How to cite this article: |
Roy I, Jain A, Kumar M, Agarwal S K. Bacteriology of neonatal septicaemia in a tertiary care hospital of northern India. Indian J Med Microbiol 2002;20:156-9
|How to cite this URL: |
Roy I, Jain A, Kumar M, Agarwal S K. Bacteriology of neonatal septicaemia in a tertiary care hospital of northern India. Indian J Med Microbiol [serial online] 2002 [cited 2014 Mar 7];20:156-9. Available from: http://www.ijmm.org/text.asp?2002/20/3/156/6942
In spite of great advances in antimicrobial therapy, neonatal life support measures and the early detection of risk factors, septicaemia continues to be a major cause of mortality and morbidity among neonates around the world. Neonates are particularly vulnerable to infections because of weak immune barrier. Moreover several risk factors have been identified both in the neonates and in the mother which make them susceptible to infections. Blood stream infections have been quoted as the most common infections in this age group. A very wide spectrum of organisms has been described for cases of neonatal septicaemia and this spectrum is subject to geographical alterations. Moreover, the organisms isolated are often resistant to multiple antimicrobials which make the treatment difficult and grave sequelae ensue. Thus, the need for bacteriological monitoring in neonatal wards cannot be overemphasized.
The present study was undertaken to describe the spectrum of isolates in cases of neonatal septicaemia, and their antimicrobial susceptibility pattern.
| ~ Materials and Methods || || |
A total of 728 neonates admitted in neonatology ward were enrolled. This centre caters primarily to out-born babies. All the babies born to mothers with or without risk factors were prospectively enrolled. One to two millilitre of blood was collected from each patient using proper aseptic precautions and inoculated immediately into 5 mL of brain heart infusion broth with 0.025% Sodium polyanethol sulfonate as anticoagulant (HiMedia Laboratories, Mumbai). A second similar sample was obtained on the same day from a different site after few hours to rule out contamination with skin flora. The broths were subcultured after overnight incubation on chocolate agar, MacConkey agar and 5% sheep blood agar. A negative result was followed up by examining the broth daily and doing a final subculture at the end of 7 days or at appearance of turbidity, whichever was earlier. Any growth was identified by colonial characteristics and standard biochemical tests. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disc diffusion method as per the NCCLS recommendations.
| ~ Results || || |
Out of 728 cases studied, growth of bacteria was obtained in 346 (47.5%) blood samples. Multiple bacterial growth was obtained from 4 samples (0.54%). Total number of bacterial isolates was 350 and Candida spp. was isolated from 50 samples (6.8%). Of the bacterial isolates the most frequent offender was Klebsiella spp. (24.6%) followed by Enterobacter spp. (22.9%), CONS (16.6%), S. aureus (14%), E. coli (14%) and other less frequent isolates [Table - 1]. In early onset disease (age < 1 wk), the most common isolate was Klebsiella spp. (25.8%) and Enterobacter spp. (22.4%) followed by E. coli (14.5%). In late onset illness (age > 1 wk) however, Enterobacter spp. (23.3%) was the major pathogen followed by CONS (22.3%) [Table - 1].
Study of maternal risk factors revealed 32.08% of mothers had preterm labor, 28.9% had PROM and 5.2% had intra partum fever. The most frequent neonatal risk factor was low birth weight affecting 63.8% of the neonates [Table - 2].
The antimicrobial susceptibility testing revealed that resistance to penicillin was frequent in S. aureus (95.9%) and CONS (89.6%) than in Enterococcus spp. (33.3%) [Table - 3]. Resistance to amikacin was relatively uncommon in the former two isolates.
None of the gram positive isolates were resistant to the glycopeptides - vancomycin and teicoplanin. Most of the gram negative isolates of Enterobacteriaceae family were resistant to ampicillin and amoxycillin [Table - 4].
Resistance to cefotaxime ranged from 63.7% to 65.3% and that to ceftazidime ranged from 40.8% to 53.7% of isolates. Resistance to amikacin was less frequent than resistance to gentamicin. Enterobacteria were less frequently resistant to ciprofloxacin.
| ~ Discussion || || |
The varying microbiological pattern of neonatal septicaemia warrants the need for an ongoing review of the causative organisms and their antibiotic sensitivity pattern. Some reports from home and abroad show the incidence of neonatal septicaemia to vary between 36% to 55%.,, In our study, incidence of neonatal septicaemia confirmed by culture was 47.5%. An area based knowledge of the bacteriological spectrum is essential because the first antibiotic administered will not wait for the culture results and keeping in mind the high morbidity and mortality associated with neonatal sepsis, a right choice for such empiric therapy is of utmost importance. In western countries, antibiotics of choice are directed towards group B Streptococcus and E. coli. But in tropical areas, early onset neonatal infections may be caused by multiresistant hospital acquired bacteria, which are transmitted during delivery by lack of hygiene. These organisms are usually resistant genera of Enterobacteriaceae family, Pseudomonas spp. and Staphylococcus. In our study, the most frequent isolate was Klebsiella (24.6%) and this was in accordance with other Indian studies., The spectrum of bacteria causing neonatal septicaemia in our hospital is comparable to that of National Neonatal Perinatal Network Database report. Group B Streptococcus, as is evident from the same report, is not common in our country and we also did not isolate group B Streptococcus from our cases. In our hospital, there was an overall predominance of gram negative septicaemia with a strikingly high isolation rate for Enterobacter spp. (22.9%) which is higher than any of reported incidences already referred. We identified Klebsiella spp. to be the most frequent offender in the first week of life (25.8%) followed by Enterobacter spp. (22.4%). E. coli (14.5%) takes the third place in contradiction to the western reports. In the late onset disease, the commonest isolate was Enterobacter spp., which can be a major threat to neonates in tertiary care hospitals. Similar concern regarding Enterobacter sepsis was expressed in a report from Karachi in 1996. An incidence of 14% for CONS in the first week of life is also a matter of concern. This bacterium is often regarded as a contaminant, possibly from the skin, but Leon et al opined that the presence of this bacterium in the blood can no longer be taken as contamination especially in patients in critical care units. Most of the cases detected by blood culture occurred in the first week of life (71.3%). This calls for close monitoring of the newborns especially those in high risk categories as soon as they are born. Administration of empiric antimicrobial therapy aimed at gram negative bacteremia in suspected cases of neonatal septicaemia is suggested.
The major gram positive isolates viz. S. aureus and CONS were frequently found to be penicillin resistant. Resistance percentage to other antimicrobials like erythromycin, gentamicin, tetracycline and ciprofloxacin were above 40%. High frequency of resistance against these b lactam and non b lactam antibiotics have been seen in MRSA and MRCNS. None of our strains showed resistance against vancomycin or teicoplanin and these drugs therefore can be effectively used if methicillin resistance is suspected during treatment.
Gram negative isolates of Enterobacteriaceae family offered resistance to anti gram negative penicillins as well as to extended spectrum cephalosporins in quite large numbers, making it clear that the use of these drugs alone may be ineffective. It was however interesting to note that ciprofloxacin resistance was less frequent among these bacteria. This fact was further supported by in vivo results of the drug as could be learnt from the clinical side. A study by Khaneja et al (1999) also found quinolones to be effective in the treatment of multidrug resistant gram negative infections in patients including premature and extremely low birth weight infants.
The high frequency of resistance to b lactam antibiotics can well be due to their indiscriminate use as first line drugs. This can be avoided by using drugs to which most organisms were susceptible. In case of gram negative isolates, which turned out to be the major pathogens, ciprofloxacin and amikacin are good alternatives and they will also provide some economical relief to the patient.
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