Indian J Pcdiatr 1992; 59 : .309-312

Citrobacter Sepsis in Infants R.P. Sugandhi, V.K. Beena, P.G. Shivananda and Meera Baliaga*

DeparOnents of Microbiology and *Pediatrics, Kasturba Medical College, Manipal A study of blood cultures from 320 cases of neonatal sepsis showed 136 (42.5%) to be positive for bacterial growth; of these 82 (60.29%) isolates being gram negative bacilli. Citrobacter was the commonest gram negative bacilli isolated. Other commonly isolated gram negative organisms were Pseudomonas, Klebsiella, Salmonella typhimurium, Acinetobacter and Escherichia coli. Antibiotics susceptibility pattern revealed the isolates to be resistant to commonly used antibiotics.

Key words : Citrobacter, Neonatal sepsis; Antibiotic susceptibility. Gram negative bacilli are important agents causing neonatal sepsis. Up to scvcnty per cent of nconatal nosocomial infcctions arc caused by these organisms 1-3.While Escherichia coli continues to bc the most common pathogen, other multidrug resistant gram negativc bacilli likc salmonella typhimurium, klcbsiclla and citrobacter species are gaining importance as causative agcnts of nconatal septicemia. 4-6 Citrobatter species once recognised as saprophytes arc known to cause neonatal meningitis and sepsis. 71~ In this study, sepsis caused by citrobacter species has been described. Antibiotic susceptibility pattern has also becn studied since most of thcm are multidrug resistant and cause considerable mortality and morbidity in newborn infants. MATERIAL AND METHODS Blood cultures were done on 320 newborn Reprint requests : Dr. P.G. Shivananda, Professor & Head, Department of Microbiolo~', Kasturba Medical College, Manipal-576 119.

infants with suspected sepsis admitted to Kasturba Medical College and Hospital neonatal intensive care unit for a period of one year. One ml of blood was collected from pcripheral vein or by heal prick after cleaning the area with spirit and iodine and Iransfcrrcd to 30 ml of brain hcart infusion broth. Inoculated bottles wcre incubated at 37~ for 7 days. Subcultures made alter 24, 72 hours and after 7 days. Subcultures wcrc also done if there was any visible growth, onto blood agar and MacConkey's agar. Identification of the organism was done by standard biochemical and serological tests) I Sccond blood culture was done for those cases whose condition dctcrioratcd even after specific treatment. Second blood cuhurc was also done for those cases from which citrobacter was isolated Io study the therapeutic response. Ccrcbrospinal fluid (CSF) cuhure was done for 80 cases who showed signs of ccntral nervous system involvement. Ccntrifugcd deposits of CSF was cuhurcd on

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THE INDIAN JOURNAL OF PEDIATRICS

blood agar, MacConkcy agar and chocolate agar. Umbilical stump culture was done from 65 infants who had suspected sepsis to rule out Umbilical colonisation. These 65 infants had cither discharge from umbilicus t~r signs of inflammation. Antibiotic sensitivity was done for the isolates by disc diffusion method) 2

septran, chloramphenicol and telracycline (Table 2). DISCUSSION

Although citrobacter species were first identified in the early 1930's as Citrate positive coliforms, they were not recognised as a genus until 1966. Two major species havc been identified. C. freundii which is comRESULTS monly isolated and a more recently recogniOf the 320 blood cnltures from neonates sed species C. diversus. Citrobacter species 136 (42.5%) showcd bacterial growth. SLx- are frequently found in soil and water and tccn isolates were citrobacter species; have becn described as normal inhabitants (citrobacter freundii 14 and citrobacter of the intestinal tract of man and animals. divcrsus 2) as shown in Table 1. Citrobacter Disease due to citrobacter freundii have was Ihc commonest gram negative bacilli been reported in adults when it has been isolated from these infants. Of the eighty isolated from the sputum, urine and wounds CSF culture, 16 showed bacterial growth and in a case of subacute bacterial cndocarand citrobactcr was isolated from four CSF, ditis; it was cultured from the blood. It has 24 umbilical stump showed bacterial growth also been reported to cause meningitis and and 6 of them were citrobacter species. brain abscess] Citrobacter diverstts is more Most of the Citrobacter species were mul- frequently encountered in neonatal menintidrug resistant but sensitive to gentamycin, gitis and other neonatal infections than TA,I.F.1. Number o[ Gram Negative Bacilli Isolated from Blood, CSF and Umbilical Stump Positive Cultures Species of bacteria

Blood

CSF

Umbilical stump

No

%

No

%

14 2 9 12 13

17.07 2.43 10.97 14.63 15.85

2 2 3

12.5 12.5 18.75

1

1,21

15 14

18.29 17.07

Flavobacteti~tnJ i11en h~gosepticum

1

1.21

Alkaligenes species

1

1.21

C#robacterfivundii Citlohacter divetxus l:~chelichia coli Klebsiella 5"abmmella o'phinntlitm~ Entcrobacteriaceae Pset~domonas spedes Acinetobact er calcoaceticus

-

No 4 2 4

-

1

4

25.0

--

4

25.00

-

-

1

6.25

8 4

1

% 16.6 8.33 166 4.16 -

33.33 16.6 4.16

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7"1!1":INDIAN JOURNAL OI: PEDIATR1C~S

citrobacter fi'eumlii, s In this study, citrobacter (16 cases) were m o r e c o m m o n than other c o m m o n l y enc o u n t e r e d g r a m negative bacilli like escherichia colt (9 cases), citrobactcr was isolated from four C S F and six umbilical s t u m p as wcll. N o s o c o m i a l o u t b r e a k of citrobactcr infection due to umbilical colonization has been described e a r l i c r J 3 Umbilical colonization was d e t e c t e d in 4 babies in this study. C i t r o b a c t c r could not be isolated from the e n v i r o n m e n t cullurcs of neonatal intensive care unit. A h h o u g h earlier r e p o r t s of citrob a c t e r infection in infants have b e e n suspecled to be nosocomial in origin, c o m m o n source o f out breaks have not been identified and m o d e of transmission have not b e e n well defined. 7q~ In this study, c o m m o n source and m o d e of transmission could not bc detected. Source could be from the infants intestine. Infants intcstinal carriage is i m p o r t a n t in p e r p e t u a t i n g the organismJ a T o conclude, citrobactcr is an i m p o r t a n t g r a m ncgativc bacilli which causes neonatal sepsis and should be b o r n e in mind while dealing with neonatal septicaemia. It is as c o m m o n as Escherichia colt or klebsiella, and m u h i d r u g resistant strains can cause considerable morbidity and mortality.

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