Indian Pediatrics 2001; 38: 68-71
Nosocomial Infections in Newborns
Shoaib E. Hasani
Haris M. Khan
Azra J. Ahmad*
Nosocomial infections continue to remain an important cause of morbidity and mortality in the neonatal period(1). The infection rates greatly exceed the rates observed in other parts of the hospital(2). The changing pattern and frequent emergence of resistant bacteria make the problem more difficult. This study was undertaken to find out the incidence of neonatal nosocomial infections, its presenting features, bacteriology with antimicrobial sensitivity and risk factors in a teaching hospital with a secondary level of a neonatal care.
Hospital born neonates transferred to the neonatal unit after birth and available in the unit for at-least 48 hours comprised the study group. Those who did not manifest signs of infection were followed upto 72 hours or more after discharge to detect cases who may be incubating an infection at the time of discharge. Nosocomial infection was considered to be present if onset of infection was found after 48 hours of birth on the basis of clinical features and culture positivity. Neonates presenting with infection beyond 48 hours and under 7 days of life but with maternal predisposing factors such as premature rupture of membrances, maternal fever and foul vaginal discharge were not considered to be nosocomial in origin.
Blood culture and various other clinical specimens were collected from the neonates in whom infection was suspected. Culture and identification of the isolates and antibiotic sensitivity was done as per standard methods(3).
Various risk factors were studied including peripheral vascular catheterization, low birth weight and resuscitation at birth. These risk factors were analyzed by univariate analysis.
During the study period of one year out of a total of 3784 live births, there were 486 (12.8%) newborns who were admitted to the neonatal unit and all of these newborns were inborn babies. Amongst these 203 (40.1%) neonates became eligible for inclusion in the study. Of these 203 newborns 20 had gestation period <28 weeks, 29 had gestation period <32 weeks and 154 newborns were of >32 weeks gestation. There were 54 neonates who developed nosocomial infection leading to an incidence of 26.9%. The overall noscomial infection rate in terms of infection per 1000 days was 20.4/1000 patient days. Amongst these 54 neonates, 34 were male and 20 were female newborns. The average number of days of stay of the infected newborns was 12.4 days.
The commonest nosocomial infection was septicemia which was observed in 45 cases followed by umbilical sepsis in 7.4% (Table I). Gram negative organisms were isolated in nearly 70% of the cases with Klebsiella being the commonest organism causing the infections, accounting for 55.6% of the cases. Staph. epidermidis was the commonest Gram positive organism isolated and the second commonest organism (12.9%) causing the nosocomial infections. Other organisms isolated were S. aureus (9.5%), Acinetobacter (17.4%), S. faecalis (5.5%), E.coil (3.7%) and P. mirabilis (1.9%). Among fungi, Candida albicans was isolated from 2 cases of septicemia.
The commonest clinical feature in septicemic newborns was refusal of feeds, which was present in 77% of the cases. The second commonest (60%) clinical feature was a change in temperature with hyperthermia being more common than hypothermia, being present in 46.6% of the cases. Lethargy (51%), abdominal distension (35%) and respiratory distress (26%) were the other common clinical presenting features. The overall mortality in the newborns due to nosocomial infection was 20.4%. An inverse relationship was observed in relation to mortality and birth weight; as the birth weight of the newborn decreased, higher was the mortality. Maximum mortality was observed in neonates weighing less than 1 kg where out of 4 neonates who developed septicemia 3 (75%) died (Table II).
Several factors with a known risk for neonatal nosocomial infections were evaluated. On univariate analysis it was observed that peripheral vascular catheterization was the highest risk factor associated with neonatal nosocomial infections. Out of the 54 neonates, 49 had peripheral vascular catheterization. Other risk factors found to be significantly associated with nosocomial infections were low birth weight and male sex. Factors predisposing newborns to nosocomial infections were vaginal mode of delivery, resuscitation at birth and the use of porphylactic antibiotics (Table III).
In our country, the reporting of neonatal nosocomial infections has not been uniform(4). The incidence in our nursery was found to be 26.9% which is higher than that reported by other workers(5,6).
Nosocomial septicemia remains a signifi-cant cause of morbidity and mortality in the newborns, more so in developing countries. This may be due to delivery and post natal follow up in an unclean environment and non-adherence to aseptic measures which increases the chance of contamination with infective organisms. In our study also, septicemia was found the commonest (90%) infection which is in concordance with the results of other workers(7).
The frequency of infection by various organisms varies from one institution to another and even from year to year in the same institution. In our country Gram negative organisms are mostly responsible for neonatal nosocomial infections(8). In this study Klebsiella, E. coli, Acinetobacter and Proteus were the predominant pathogens found in nearly 70% of the cases.
The result of drug sensitivity revealed that most of the organisms were sensitive to ami-kacin and ciprofloxacin whereas gentamicin, ampicillin and chloramphenicol were less effective drugs. An interesting finding was that none of the gram negative organisms except for one isolate of acinetobacter were found to be resistant to cefotaxime or ceftazidime. The unit antibiotic policy is to start treatment with ampicillin and gentamicin and wait for anti-biotic sensitivity results. In some cases amika-cin is used instead of gentamicin. The sensiti-vity pattern varies in different parts of the same country as well as at various times in the same hospital(9). This reflects the pattern of antibiotic usage and the frequent emergence of resistant strains.
The overall mortality of the infected newborns in our study was observed as 24.4%. The birth weight of a neonate is unquestionably the most important factor in its survival. The inverse relationship between birth weight of the newborn and mortality observed in our study truly reflects the point. In neonates weighing less than 2.5 kg the mortality was 38.4% whereas some workers(9) have reported rates as high as 61.4%.
Peripheral vascular catheterization has been reported to be responsible for a considerable proportion of septicemic cases(4,10). In our study, peripheral vascular catheterization was the highest risk factor associated with neonatal nosocomial infections. This stresses the need for strict adherence to aseptic protocol in a neonatal unit if infection rates are to be kept low.
Contributors: AM coordinated the study particularly its design and interpretation; she will act as the guaran-tor for the paper. SEH participated in data collection and helped in drafting the paper. HMK helped in processing the data. AJA provided the material from the neonatal unit.