Microbial profile of neonatal infection in Coimbatore

Polymicrobial bloodstream infections in the neonatal intensive care unit are associated with increased mortality: a case-control study

Background

Polymicrobial infections in adults and children are associated with increase in mortality, duration of intensive care and healthcare costs. Very few studies have characterized polymicrobial bloodstream infections in the neonatal unit. Considerable variation has been reported in incidence of polymicrobial infections and associated clinical outcomes. We characterized the risk factors and outcomes of polymicrobial bloodstream infections in our neonatal units in a tertiary hospital in North America.

Methods

In a retrospective case control study design, we identified infants in the neonatal intensive care unit with positive blood cultures at Texas Children’s Hospital, over a 16-year period from January 1, 1997 to December 31, 2012. Clinical data from online databases were available from January 2009 to December 2012. For each polymicrobial bloodstream infection (case), we matched three infants with monomicrobial bloodstream infection (control) by gestational age and birth weight.

Results

We identified 2007 episodes of bloodstream infections during the 16 year study period and 280 (14%) of these were polymicrobial. Coagulase-negative Staphylococcus, Enterococcus, Klebsiella and Candida were the most common microbial genera isolated from polymicrobial infections. Polymicrobial bloodstream infections were associated with more than 3-fold increase in mortality and an increase in duration of infection. Surgical intervention was a significant risk factor for polymicrobial infection.

Conclusion

The frequency and increased mortality emphasizes the clinical significance of polymicrobial bloodstream infections in the neonatal intensive care unit. Clinical awareness and focused research on neonatal polymicrobial infections is urgently needed.

Staphylococcus aureus- the predominant pathogen in the neonatal ICU of a tertiary care hospital in amritsar, India

BACKGROUND

An early treatment and the appropriate and the rational use of antibiotics would minimize the risk of severe morbidity and mortality in neonatal sepsis, and reduce the emergence of multi-drug resistant organisms in intensive care units. For the success of an early empiric treatment, a periodic review of the cases to assess any changing trends in the infecting organisms and their antimicrobial susceptibility is important.

AIM

To study the most commonly encountered bacterial pathogens which caused neonatal sepsis and their sensitivity patterns, so that guidelines could be prepared for a rational antibiotic therapy.

SETTING AND DESIGN

This was a retrospective study which was conducted in the Department of Microbiology and the Neonatal Intensive Care Unit (NICU) at SGRDIMSAR, Amritsar, during June 2011 to June 2012.

METHODS AND MATERIALS

Blood specimens for culture were drawn from 311 newborns who were admitted in an NICU with sepsis. The specimens were inoculated into brain heart infusion broth. Subcultures were performed on days 1, 2, 3, 5, 7 and 10. The isolates were identified by doing standard biochemical tests. The antibiotic resistance patterns of the isolates were studied by the Kirby Bauer disc diffusion technique.

RESULTS

A total of 131 organisms were isolated from the 311 blood cultures. These included Staphylococcus aureus (n=68), Coagulase Negative Staphylococcus (CoNS) (n=30), Klebsiella pneumoniae (n=10), Acinetobacter baumannii (n=9), Escherichia coli (n=05), Enterobacter cloacae (n=04), Citrobacter diversus (n=02), Pseudomonas aeruginosa (n=02) and Candida (n=01). Staphylococcus aureus was the main pathogen in both early and late-onset sepsis. On antibiotic sensitivity testing, 57.35% of the Staphylococcus aureus isolates were found to be methicillin resistant. More than 90% gram negative rods were resistant to amikacin. The resistance to the third generation cephalosporins varied between 50-55%. The resistance to ciprofloxacin was quite high; however, most of the isolates were susceptible to levofloxacin. A majority of the isolates were susceptible to piperacillin- tazobactum and imipenem.

CONCLUSION

The present study emphasized the importance of periodic surveys on the microbial flora which was encountered in particular neonatal settings to recognize the trend.

Clinical significance of polymicrobial bacteremia in newborns

OBJECTIVE

To identify whether polymicrobial bacteremia in newborns is associated with any predisposing factors, distinguishing clinical features, or higher mortality.

METHODS

Results of blood cultures obtained over a period of 1 year from neonates admitted to the paediatric ward and Neonatal Intensive Care Unit of a tertiary care hospital were retrospectively analysed. The study group included all cases with polymicrobial bacteremia (isolation of two or more organisms). Controls (double the number of study cases) were randomly selected from the monomicrobial group. Case records of included cases were retrieved and scrutinized.

RESULTS

Of 770 positive cultures during the study period, 52 (6.8%) cultures were positive for more than one organism. Complete case records were retrieved for 40 polymicrobial and 78 monomicrobial cases. The two groups were comparable for maternal and neonatal parameters including: maternal and obstetric complications; period of gestation; mode of delivery; birthweight and perinatal asphyxia; clinical symptomatology; invasive therapeutic interventions; and mortality.

CONCLUSIONS

Isolation of more than one organism from the blood culture of a suspected septic newborn is not rare. It does not always represent a true invasion by multiple organisms. Polymicrobial isolation per se should not be the criterion for hastily changing the therapeutic decisions.

Bacteraemia in children

OBJECTIVES

(i)To know the etiology of bacteraemia in children, (ii) To learn the antibiotic sensitivity pattern of the isolates.

METHOD

Over the period of thirteen months 4,368 blood samples (for blood culture) were collected from children in the age group of 0 day-14 years, suspected of having fever and sepsis. Blood samples were collected for blood culture from each case. Organisms were isolated and identified by conventional methods. Antibiotic susceptibility for each isolate was determined by using modified Stokes method.

RESULT

1,001 cases (22.9%) were culture positive. Incidence of bacteraemia in neonates was 521(33.94%). Gram negative organisms were the most predominant isolates (88.8%). Commonest was Klebsiella 471 (47.1%) followed by Salmonella sp. 162 (16.2%) and Pseudomonas 80 (8%) whereas in gram positive, Staphylococcus aureus 76 (7.6%) was the most common. Maximum sensitivity was seen by sulbactum/cefaperazone combination-969 (98.2%) by all isolates. Linezolid 97 (99.0%) was the most sensitive drug for gram positive isolates.

CONCLUSION

Gram negative multidrug resistant organisms were the main cause of septicemia in all the age groups. Therefore great caution is required in selection of antibiotic therapy.

Neonatal sepsis: Staphylococcus aureus as the predominant pathogen

96 consecutive inborn neonates with blood culture proven bacterial sepsis during the period January to June 1997 were studied. Lethargy with refusal of feeds (28%), fever (28%) and respiratory distress (31.3%) were the major presenting features. Half of them (n = 48) were of early onset (< 48 hours) and the remaining half were of late onset (> 48 hours). Staphylococcus aureus (n = 59, 61.5%) was the predominant pathogen and 66% of them were methicillin resistant followed by Klebsiella pneumoniae (n = 24, 21.9), Escherichia coli (n = 13, 13.5%) and streptococci (n = 3, 3.1%). Antibiotic resistance was common, with the sensitivity to various antibiotics being ampicillin 19%, gentamicin 21.6%, cefotaxime 32.8%, amikacin 50%, chloromycetin 59.6% and ciprofloxacin 90.3%.