© Inštitut za sanitarno inženirstvo, 2019
International Journal of sanitary engineering researchVol. 13  No. 1/2019 S it r  Engineering Research 39
The incidence of rotavirus 
infection compared to 
bacterial infections in 
different age groups of 
pediatric patients with 
gastroenteritis
Tatjana BABIĆ1*, Biljana MILJKOVIĆ-SELIMOVIĆ2, 
Dobrila ĐORĐEVIĆ-STANKOVIĆ2, Branislava KOCIĆ2, 
Miloš RANĐELOVIĆ1, Predrag STOJANOVIĆ2, 
Milena BOGDANOVIĆ1, Vukica ĐORĐEVIĆ2 
ABSTRACT
Rotavirus is the important cause of acute gastroenteritis in pediatric patients. 
The aim of the present research was to determine the incidence of rotavirus 
infections in infants and children up to seven years of age in the town of 
Niš. Seasonal prevalence of rotavirus-associated acute gastroenteritis was 
also evaluated. An enzyme immunoassay (RIDASCREEN® Rotavirus; 
R-Biopharm AG, Darmstadt, Germany) was used to detect rotavirus in the stool 
specimens of 1,156 patients (newborns up to 7 years of age) presenting with 
gastroenteritis. Identification of bacteria and yeasts was performed by classical 
methods. The overall incidence of rotavirus in examined children was 5.97%. 
Among 144 hospitalized children, rotavirus infection was diagnosed in 28 
(19.44%). In 1,012 children treated in outpatient setting for diarrheal 
diseases, rotaviruses were found in 41 (4.05%). The highest incidence of 
rotavirus infection was among the patients of one year of age. Among 1,156 
pediatric children tested, bacterial pathogens were found in 6.31% and the 
most frequently isolated pathogens were Campylobacter spp. and Salmonella 
enteritidis. The highest prevalence of GE was recorded in the colder season, 
peaking in April (15.94%). Rotaviruses are an important factor in the etiology 
of the acute diarrheal diseases, especially in children hospitalized during the 
winter/spring season. 
Key words: rotavirus; gastroenteritis; incidence; children
POVZETEK
Rotavirus je pomemben vzrok akutnega gastroenteritisa pri otrocih. Namen 
predstavljene raziskave je ugotoviti pojavnost rotavirusnih okužb pri dojenčkih 
in otrocih do sedmega leta starosti v mestu Niš. Ocenjena je bila tudi sezonska 
razširjenost rotavirusa povezanega z akutnim gastroenteritisom. Za odkrivanje 
rotavirusa v vzorcih blata pri 1156-ih bolnikih (novorojenčki in otroci do sedmega 
1 Center for Microbiology, Public Health 
Institute Niš, Bul. Dr Zorana Đinđica 50, 
18000 Niš, Republic of Serbia
2 University of Niš, School of Medicine, 
Bul. Dr Zorana Đinđica 81, 18000 Niš,  
Republic of Serbia
*	Corresponding author
dr. Tatjana Babić, dr. sc. med. 
Center for Microbiology 
Public Health Institute Niš 
Bul. Dr Zorana Đinđica 50 
18000 Niš, Republic of Serbia  
E-mail: tatjanab969@yahoo.com
Received: 28. 05. 2019 
Accepted: 24. 07. 2019
Original scientific article 
© Inštitut za sanitarno inženirstvo, 201940

leta starosti) z gastroenteritisom, je bil uporabljen encimski imuno test (RIDA-
SCREEN® Rotavirus; R-Biopharm AG, Darmstadt, Germany). Identifikacija 
bakterij in kvasovk je bila izvedena s klasičnimi metodami. Skupna pojavnost 
rotavirusa med pregledanimi otroci je bila 5,97 %. Med 144 hospitaliziranimi 
otroki, je okužba z rotavirusom bila diagnosticirana pri 28-ih (19,44 %). Pri 1012 
otrocih, ki so jih zdravili v ambulanti, zaradi diarejskih bolezni, so rotavirusi bili 
najdeni pri 41-ih (4,05 %). Najvišja pojavnost rotavirusnih okužb je bila pri 
enoletnih otrocih. Med 1156 testiranimi otroci, so bili bakterijski patogeni najdeni 
pri 6,31 %, najpogosteje izolirani patogeni so bili Campylobacter spp. in 
Salmonella enteritidis. Največja razširjenost GE je bila zabeležena v hladnejši 
sezon, z vrhuncem v aprilu (15,94 %). Rotavirusi so pomemben dejavnik v 
etiologiji akutnih diarejskih bolezni, še posebej pri otrocih hospitaliziranih v 
zimski/pomladni sezoni. 
Ključne besede: rotavirus; gastroenteritis; pojavnost; otroci
INTRODUCTION
Rotavirus (RV) has been shown to be the leading cause of severe acute 
diarrhea in pediatric patients [1, 2]. This segmented double-stranded 
RNA (60-80nm) viruses belong to the family Reoviridae. They are 
classified into seven serogroups (A-G) based on electrophoretic mobility 
of genomic segments and group-specific VP6 antigen of the internal 
capsid [3]. Further division to serotypes is based on dominant antigens 
VP4/VP7 of external capsid. Viruses of the serogroup A cause human 
disease and serogroups B and C are rarely involved [4]. 
Clinical presentation of human RV infection can vary from asymptomatic, 
mild or severe gastroenteritis (GE) disease that can result in a lethal 
dehydration. Clinical manifestations are a sudden onset of vomiting, 
diarrhea lasting 5–6 days on the average, and dehydration [5]. In some 
patients, mucosal infection can spread systemically with viral replication 
in different parts of the body [6]. Oral rehydration corrects the electrolyte 
and water loss, indicating that enterocytes in the small intestine have a 
functional sodium-glucose co-transporter [7]. 
The highest rate of infection has been reported in patients 6 to 24 
months of age [8] in both developed and developing countries. However, 
deaths due to RVGE (Rota viral gastroenteritis) occur mainly in the low 
income countries of Asia, Africa and Latin America among the children 
below 5 years of age [9]. RV causes almost 111 million gastroenteritis 
(GE) episodes, 25 million clinical visits, 2 million hospitalizations and 
more than 453,000 deaths each year [10].
Seasonal distribution of rotavirus cases may vary by geographical 
location: in temperate climates most cases are observed in fall, winter 
and spring months [11], while in tropical countries there are not 
seasonal peaks [12]. 
Electron microscopy analysis has proven to be a valuable technique in 
the diagnosis of these agents in patients with acute infections. However, 
enzyme immunoassays are rapid, sensitive, and specific alternatives to 
electron microscopy providing the detection of infectious agents in 
Rotavirus (RV) has been 
shown to be the leading 
cause of severe acute 
diarrhea in pediatric patients.
Seasonal distribution of 
rotavirus cases may vary by 
geographical location.
T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al. The incidence of rotavirus infection compared to bacterial infections in different age groups
International Journal of Sanitary Engineering Research Vol. 13  No. 1/2019 41
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diarrheal stools specimens [13]. There are several commercial enzyme 
immunoassay kits which enable detection of all serotypes of group A 
rotaviruses [14]. Molecular techniques, for example reverse 
transcription-polymerase chain reaction (RT-PCR), enable diagnosis and 
identification of all serogroups and serotypes of human rotavirus [15].
Limited data exist on the importance of rotavirus in the etiology of 
diarrheal disease in all parts of Serbia due to a lack of detection and 
reporting policy of microbiological laboratories.
The objectives of the present prospective study was to determine the 
incidence of rotavirus infection in infants and children up to seven years 
of age presenting with GE, distribution of infection by the factors of age 
and gender, association between the infection caused by rotaviruses 
and bacteria, and seasonal prevalence of rotavirus-associated acute 
gastroenteritis. 
METHODS
Patients
In the Center for Microbiology, Public Health Institute Niš, stool 
specimens from 1,156 pediatric patients (newborns up to 7 years of age) 
presenting with GE were processed for bacteriology testing and for 
detection of rotaviruses over a two-year period (January 2009 – July 
2010). 
Rotavirus detection
Rotavirus was detected from fresh, unfrozen samples of diarrheal stools. 
An enzyme immunoassay (RIDASCREEN® Rotavirus; R-Biopharm AG, 
Darmstadt, Germany) was used to detect rotavirus in the stools 
specimens according to the manufacturer’s instructions.
Bacterial detection and identification
For bacterial detection, fecal samples were processed by standard 
bacteriological methods for Salmonella spp., Shigella spp., Yersinia 
enterocolitica (Y. enterocolitica), Bacillus cereus (B. cereus), and 
Campylobacter spp. Diarrheal toxins of B. cereus were confirmed using 
the GLISA-Rapid Test (Gold Labelled ImmunoSorbent Assay) for the 
qualitative detection of enterotoxin producing B. cereus: Duopath® 
Cereus for the determination of the NHE and HBL enterotoxins (Merck 
KGaA Darmstadt, Germany). Yeasts were detected to the genus level on 
blood agar. 
Statitistical methods
Data were analyzed using the Excel (Microsoft) and SPSS software 
(SPSS). In order to determine the differences in the proportions of RVGE 
cases for the factors of gender, age, hospitalization and seasonal of 
distribution of RV, the two-tailed P value χ2 test was used. The result 
was significant at p < 0.05. 
Limited data exist on the 
importance of rotavirus in the 
etiology of diarrheal disease 
in all parts of Serbia due to a 
lack of detection and 
reporting policy of 
microbiological laboratories.
 T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al.The incidence of rotavirus infection compared to bacterial infections in different age groups...
© Inštitut za sanitarno inženirstvo, 201942
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RESULTS
A total of 1,156 children below eight years of age with acute GE were 
included in the study, with a mean age of 2.2 years. There were 144 
hospitalized and 1,012 out-patients (Table 1). Pathogens were detected 
in 139 (11.42%) stool samples taken from 1,156 subjects. For all 
tested pathogens, 1,024 (88.58%) samples were negative. RVGE and 
bacterial gastroenteritis were detected in 69 and 70 cases, respectively. 
There was not a significant difference between the frequency of RV and 
bacterial infection (p = 0.794).
Table 1. Detection of rotaviruses in stools samples of infants and younger children regarding gender and hospitalization
Investigated groups 
Number of 
subjects (%)
Sex (%) Number of 
positive (%)
Sex (%)
Male Female Male Female
Hospitalized patients 144 (12.46) 87 (60.42) 57 (39.58) 28 (19.44) 17 (60.71) 11 (39.29)
Outpatients 1012 (87.54) 577 (57.02) 435 (42.98) 41 (4.05) 24 (58.54) 17 (41.46)
Overall 1156 (100) 664 492 69 41 (59.42%) 28 (40.58%)
The overall incidence of rotavirus as the most frequent pathogen in the 
examined 1,156 children presented with RVGE (newborns up to 7 years 
of age) was 5.96% (69/1,156). Bacterial enteric pathogens of acute 
gastroenteritis were Salmonella spp., Campylobacter spp., Yersinia 
enterocolitica O3, Shigella flexneri, Bacillus cereus, with detection rate 
of 6.23% (72/1156). In one patient, Candida spp. was detected.
In hospitalized children with severe disease symptoms, rotaviral 
infection was diagnosed in 19.44% (28/144) patients. Out of 87.54% 
(1012/1156) ambulatory treated pediatric patients, 4.05% (41/1012) 
had rotavirus in their stool samples (Table 2). A significant difference 
was found in the frequency of rotavirus detection between hospitalized 
children and those who were in community (χ2 = 53.2197; p < 0.001). 
The overall highest incidence of RV infection (35.00%) was among the 
hospitalized infants of one year of age (Table 2). The incidence of 
rotavirus infection in outpatients was in the range of 1.43% to 10% 
(Table 2).
Age distribution of acute gastroenteritis cases is presented in Table 4. 
The cumulative age distribution for RV-positive cases was 75.4% (n = 
52) for patients younger than 24 months (P < 0.05) and 95.7% (n = 
66) in those younger than five years. When the dataset was analyzed 
according to the age groups, for the first 24 months (n = 52, 59.8%), 
rotavirus was the main pathogen (p < 0.05), whereas for ages 25 – 60 
months (n = 20; 47.6%), it was Salmonella spp. (p < 0.05) (Table 5). 
Furthermore, Campylobacter spp. was the main pathogen for children 
older than five years, but this difference was not significant (p = 0.629).
In the 0-24 months age group (n = 87; 63.04%), the cases of RV (n = 
52; 59.77%) outnumbered the bacterial agents (n = 23; 26.44%). In 
the two-five years age group (n = 42; 30.43%), the main bacterial 
agent was Salmonella spp. (68.96%). In nine patients older than five 
In hospitalized children with 
severe disease symptoms, 
rotaviral infection was 
diagnosed in 19.44% 
patients.
T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al. The incidence of rotavirus infection compared to bacterial infections in different age groups
International Journal of Sanitary Engineering Research Vol. 13  No. 1/2019 43
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Table 2. The presence of *RVGE in different age groups
Age
Hospitalized patients Outpatients Total patients
No % No % No %
0 – 6 months 3/31 9.68 3/87 3.45 6/118 5.08
6 months – 1 year 9/41 21.95 11/205 5.37 20/246 8.13
1 year 7/20 35.00 7/183 3.83 14/203 6.90
2 years 4/19 21.05 8/154 5.19 12/173 6.94
3 years 1/9 11.11 4/117 3.42 5/126 3.97
4 years 3/12 25.00 3/92 3.26 6/104 5.76
5 years 0/6 0 3/94 3.19 3/100 3.00
6 years 0/3 0 1/70 1.43 1/73 1.37
7 years 1/3 33.33 1/10 10 2/13 15.38
Total 28/144 19.44 41/1012 4.35 69/1156 5.96
*RVGE – Rotaviral gastroenteritis
Table 3. Detection of patients positive only to *RVGE in total number of patients 
Age
Positive hospitalized 
patients
Positive outpatients
Total number of positive 
patients
No % No % No %
0 – 6 months 3 10.71 3 7.32 6 8.69
6 months – 1 year 9 32.15 11 26.82 20 28.98
1 year 7 25.00 7 17.07 14 20.29
2 years 4 14.29 8 19.51 12 17.39
3 years 1 3.57 4 9.76 5 7.25
4 years 3 10.71 3 7.32 6 8.70
5 years 0 0.00 3 7.32 3 4.35
6 years 0 0.00 1 2.44 1 1.45
7 years 1 3.57 1 2.44 2 2.90
Total 28 100 41 100 69 100
*RVGE – Rotaviral gastroenteritis
Table 4. Total pathogens distribution according to the patients’ age
Age groups, 
‡mo
No.
The number of identified pathogens, No (%)
†RV Salmonella
Campylo-
bacter
Y. entero-
colitica O3
S. flexneri 
2
B. cereus Coinfections
0 – 24 87 52* (75.4) 14 (38.9) 18 (62.1) 4 (80.0) 0 1 (100) 2 (66.7)
25 – 60 42 14 (20.3) 20* (55.6) 7 (24.1) 1 (20.0) 1 (100) 0 1 (33.3)
> 60 9 3 (4.3) 2 (5.5) 4(13.8) 0 0 0 0
Total 141 69 (100) 36 (100) 29 (100) 5 (100) 1 (100) 1 (100) 3 (100)
* p < 0.05, χ2; † RV – Rotavirus; ‡ microorganism
 T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al.The incidence of rotavirus infection compared to bacterial infections in different age groups...
© Inštitut za sanitarno inženirstvo, 201944
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years of age, and in six (66.67%) cases, bacterial pathogens were 
detected, with Campylobacter spp. (n = 4; 44.5%) being the most 
common. In this group, RV was identified in three patients.
The highest incidence of total rotavirus infection was among the 
patients less than one year of age – 37.68% (26/69). Rotavirus infection 
was also diagnosed in 42.86% (12/28) hospitalized infants (0–1 year) 
with gastroenteritis (Figure 1). In all investigated children up to five 
years of age, the incidence of rotavirus infection was 95.65% (66/69).
RVGE was detected more frequent in males (41/69) than in females 
(28/69), as well as in hospitalized patients 17/28 (60.71%) compared 
to outpatients 11/28 (39.29%) (P = 0.1176). By the conventional 
criteria, this difference was not statistically significant. Of 1,156 
children tested, non-viral pathogens were found in 6.23% (1156/72). 
Table 5. Distribution of age groups according to isolated pathogens
Pathogens
Age Groups, No (%)
0 – 24 Months 25 – 60 Months > 60 Months
Rotavirus (n = 69) 52* (59.8) 14 (33.3) 3 (33.3)
Salmonella spp. (n = 36) 14 (16.1) 20* (47.6) 2 (22.2)
Campylobacter spp. (n = 29) 18 (20.7) 7 (16.7) 4 (44.5)
Y. enterocolitica O3 (n = 5) 4 (4.6) 1 (2.4) 0
S. flexneri 2 (n = 1) 0 1 (2.4) 0
Bacillus cereus (n = 1) 1 (1.1) 0 0
Coinfections (n = 3) 2 (2.3) 1 (2.4) 0
Total 87 42 9
*P<0.05, χ2
Figure 1. 
The presence of positive RVGE patient 
in different age groups
RVGE was detected 
more frequent in males 
than in females.
T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al. The incidence of rotavirus infection compared to bacterial infections in different age groups
International Journal of Sanitary Engineering Research Vol. 13  No. 1/2019 45
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The most frequently isolated pathogens were Campylobacter spp. and 
Salmonella Enteritidis (group D). RV alone was detected in 46.48% 
(66/142) of positive findings, while non-viral pathogens alone were 
found in 49.30% (70/142). Non-viral GE etiology was represented in 
the following manner: 49.32% (36/73) by Salmonella spp., 39% 
(29/73) by Campylobacter spp., 6.85% (5/73) by Yersinia enterocolitica 
O3 (5/73) and 1.37% (1/73) by Shigella spp., Bacillus cereus and 
Candida sp. each (Table 7). 
Mixed bacterial/viral infection was detected in 0.26% (3/1156) of 
investigated children (Table 6). In 139 GE patients with confirmed 
enteropathogens, mixed bacterial/viral infection was detected in 2.16% 
(3/139). 
One of 69 positive hospitalized pediatric patients with RVGE had at the 
same time the infection caused by Salmonella group B (S. Typhimurium), 
and two outpatients were co-infected with Campylobacter spp. 
Table 6. Etiologyof gastroenteritis in investigated patients 7 years of age and younger
Pathogen No. (%) of children 
†RV alone 66 (5.71)
Mixed infection (RV and bacterial pathogen) 3 (0.26)
RV +Salmonella species 1 (0.087)
RV +Shigella species 0 (0.00)
RV + Campylobacter species 2 (0.173)
Non-viral enteropathogens alone 70 (6.05)
Not detected 1017 (87.98)
†RV – Rotavirus
Table 7. The frequency of isolated non-viral pathogens in children with *GE
Microorganism No (%)
Salmonella 36 (49.32)
Salmonella group D
S. Enteritidis 29 (39.73)
Salmonella group B
S. Typhimurium
S. Abony
5 (6.85)
1 (1.37)
Salmonella group C1
S. Infantis 1 (1.37)
Campylobacter spp. 29 (39.73)
Yersinia enterocolitica O3 5 (6.85)
Shigella flexneri 2a 1 (1.37)
Bacillus cereus 1 (1.37)
Candida spp. 1 (1.37)
Total non-viral pathogens 73 (100)
*GE – gastroenteritis
 T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al.The incidence of rotavirus infection compared to bacterial infections in different age groups...
© Inštitut za sanitarno inženirstvo, 201946
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Regarding the occurrence of RV infection in relation to season, the 
highest prevalence of GE was recorded in the winter/spring season, 
with its maximum in April (the two tailed P = 0.1825, by the 
conventional criteria, this difference was not statistically significant), 
n = 11; 15.94% (Table 8 and Figure 2, 3). A decrease in RVGE 
occurred in the summer, with the lowest incidence in July (1.45%) 
(Figure 2). A statistically significant difference was found in the 
occurrence of rotavirus infection between summer months and other 
seasons of the year (Chi-square test). The two-tailed P value equals 
Table 8. Monthly distribution of bacterial and viral pathogens
Months
The number of isolated pathogens
Rotavirus Salmonella Campylobacter Y. enterocolitica S. flexneri B. cereus
January 7 3 0 0 0 0
February 7 4 1 1 0 0
March 9 0 1 1 0 0
April 11 2 5 0 0 0
May 7 8* 4 1 0 1
June 4 4 2 0 0 0
July 1 6 5 1 0 0
August 2 1 0 0 0 0
September 4 4 4 0 1 0
October 6 2 2 0 0 0
November 5 1 3 0 0 0
December 6 1 2 1 0 0
Total 69 36 29 5 1 1
*P<0.05, χ2
Figure 2. 
The monthly prevalence of RVGE 
during the investigated period
Regarding the occurrence of 
RV infection in relation to 
season, the highest 
prevalence of GE was 
recorded in the winter/spring 
season, with its maximum in 
April.
T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al. The incidence of rotavirus infection compared to bacterial infections in different age groups
International Journal of Sanitary Engineering Research Vol. 13  No. 1/2019 47
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0.0063 (p < 0.01). By the conventional criteria, this difference was 
considered to be highly statistically significant. The peak number of 
Salmonella spp. cases, which occurred in May (n = 8; 22.22%), was 
statistically significant (the two tailed P = 0.0453), while there was not 
any cases in March (Figure 3).
DISCUSSION
Acute GE is one of the most common infectious diseases with variable 
etiology depending on the age, demographic features and seasonality in 
both developed and developing countries. In addition to the bacterial 
causes such as Salmonella spp., C. jejuni, Shigella spp., viruses 
(rotavirus, norovirus, adenovirus, astrovirus) have been reported as 
etiological agents. It is thought that viruses affect all age groups and are 
responsible for the majority of GE cases [16, 17, 18]. Among the 
patients with diarrheal illness, there is a large group with indeterminate 
etiology, and therefore an accurate diagnosis is required for an effective 
treatment and prognosis.
Since we examine samples from clinic and outpatients, but not patients 
in emergency unit, it is possible that it could influence the positivity of 
the obtained results. Moreover, RV vaccine is not part of the vaccination 
policy in Serbia. 
In this study, pathogens were detected in 11.42% stool samples from 
1,156 children under eight years of age, with acute GE. However, the 
most frequent pathogen detected was rotavirus (12.7%). Other viruses 
were not searched for. Bacterial enteric pathogens of acute 
gastroenteritis included Salmonella spp., Campylobacter spp., Yersinia 
enterocolitica O3, Shigella flexneri, Bacillus cereus, with detection 
rates of 6.23%.
Figure 3. 
Seasonal distribution of acute 
gastroenteritis agents
In this study, the most 
frequent pathogen detected 
was rotavirus.
 T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al.The incidence of rotavirus infection compared to bacterial infections in different age groups...
© Inštitut za sanitarno inženirstvo, 201948
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At the pediatric emergency clinic of a university hospital in Istanbul, 
during 12 months of observation, rotavirus was the most frequent 
pathogen, with a rate of 12.7% (75/588) [19]. In Papua, New Guinea, 
rotavirus (25.6%) and adenovirus (11.6%) were the enteric pathogens 
most commonly detected [20]. In children attending day care who 
experienced substantial gastrointestinal infections due to circulating 
seasonal enteropathogens in the day care environment in the 
Netherlands in 2010–2013, rotavirus was detected in 11%, norovirus in 
10% and astrovirus in 7%. The authors demonstrated that circulating 
viruses, rather than bacteria, contribute to seasonal gastroenteritis 
experienced by children in day care [21].
In this study, RVGE was detected more frequently in hospitalized 
patients than in outpatients and the most affected group included 
infants aged six months to one year of age. RVGE was reported in 
32.15% of hospitalized children, in 26.82% of outpatient children, and 
overall in 28.98% (Table 3). It appeared that this group of patients 
comprised the mayor group seeking medical attention. The highest rate 
of RV infection has been reported in patients 6 to 24 months of age [8] 
in both developed and non-industrialized countries. Concerning the RV 
positive cases, 28.0% were younger than 24 months, 57.3% were 
between 25 – 60 months, and 85.3% were younger than five years in 
Pediatric Emergency Unit of Yeditepe University Hospital, Istanbul, 
Turkey [19]. In Papua, New Guinea, an analysis of the age distribution 
of infections between the children aged < 1 year and children aged 
1–5 years showed no significant difference in the detection rate of 
pathogens between the two age groups.Young children were much more 
likely to be admitted to hospital with acute gastroenteritis than older 
children [20]. In Palermo, Sicilia (Italy), the mean and median ages 
were 46.3 and 25.8 months, respectively (range, 4–163.6 months) 
[22].
The overall gender distribution of 69 RV positive children revealed the 
proportion of 59.42% (41/69) for male and 40.58% (28/69) for female 
patients. RVGE was detected more frequently in males than in females, 
as in 17/28 (60.71%) hospitalized and in 41/69 (59.42%) outpatients, 
without statistical significance. We could conclude that gender does not 
seem to influence the susceptibility to RV similarly to the previous 
studies [20, 22, 23].
In this study of 1,156 hospitalized patients and outpatients, the most 
frequently isolated bacterial pathogens were Salmonella spp.: S. 
Enteritidis (29), S. Typhimurium (5), S. Abony (1), S. Infantis (1) 
Campylobacter spp. (29) and Yersinia enterocolitica O3 (5). The ratio 
viral vs bacterial infections was almost the same 69:72. The review of 
clinical records of patients with an acute GE, aged less than 15 years 
presenting to the pediatric emergency department of a Portuguese 
district hospital over a 30-month period, revealed that of 216 stool 
samples, 98 (45%) were positive: Campylobacter spp. was identified in 
50%, Salmonella spp. in 28%, Yersinia enterocolitica in 10%, 
Aeromonas spp. in 9% and Escherichia coli O157 in 3% [24]. At the 
University hospital in Istanbul, Turkey, bacterial enteric pathogens of 
RVGE was detected more 
frequently in hospitalized 
patients than in outpatients 
and the most affected group 
included infants aged six 
months to one year of age.
T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al. The incidence of rotavirus infection compared to bacterial infections in different age groups
International Journal of Sanitary Engineering Research Vol. 13  No. 1/2019 49
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acute GE were Salmonella spp. and C. jejuni, with the detection rates 
of 25.6% (21/82) and 18.3% (15/82), respectively [19]. In a one-year 
investigation of hospitalized patients in Palermo, Sicily, Italy, the 
bacterial pathogen was detected in 127 (59.1%) cases. Monobacterial 
infections were detected in 26 (12.1%) patients (Salmonella spp. in 18, 
Shigella spp. in 3, C. jejuni in 5 pts), while single viral infections were 
found in 80 (37.2%) patients [22]. In Papua, New Guinea, Shigella 
spp. were the bacterial pathogens most commonly detected (26.6%) 
[20]. EPEC strains were detected in 8.5% of patients. ETEC strains 
were detected in 11.1% of the samples. Campylobacter spp. was 
detected in 4.0%, while Salmonella spp. occurred sporadically. V. 
cholerae was not detected in any patient. Our results were more similar 
to the results obtained in Mediterranean Basin (part of Istanbul, 
Palermo) than in New Guinea in Oceania (the eastern half of the island 
of New Guinea and islands in Melanesia) a region north of Australia. 
Climate, geographic, demographic and other factors might influence the 
differences in gut microbiota.
The indistinguishable clinical presentation of gastroenteritis in children, 
together with the diversity of enteropathogens, makes the assessment 
of individual contributions of enteropathogenic agents that may cause 
gastroenteritis more challenging. 
Mixed infections were detected at a high frequency (22.1%) in Papua, 
New Guinea, (20.7%) in Tanzania, as well as in other developing 
settings such as Jordan (15.5%), Libya (13.8%), Vietnam (13.5%), and 
Brazil (11.0%). On the contrary, co-infections are typically reported at 
lower frequency in the developed milieu such as Italy (9.8%), Denmark 
(1.9%), and France (1.1%), as in our country (2.16%). These findings 
might reflect low levels of sanitation and hygiene in the developing 
countries [20].
We have found 0.26% of RV mixed infections of total investigated 
children and in 2.21% of those with positive findings. This result was 
similar to those reported in UK (2%) [25] and other developed 
countries. The detected co-infections were RV and Salmonella spp. in 
one patient and RV with Campylobacter spp. in two patients. In 
Papua, New Guinea, the combination of the pathogens Shigella 
(13.1%) and rotavirus (11.1%) was most commonly detected in mixed 
infections [20]. At the pediatric emergency of a University hospital in 
Istanbul during 2009, in 184 positive stool samples only two cases of 
coinfection with bacteria-virus were recorded: in one case rotavirus, 
adenovirus and Salmonella spp., and in the other case adenovirus and 
Salmonella spp. [19]. In the study in Sicily in hospitalized patients, 
viral bacterial coinfection was present in 4.6% cases, viral/viral 
coinfection in further 4.6%, and double-viral and bacterial coinfection 
in 0.5% cases [22]. Mixed bacterial viral infection presents more 
severe clinical manifestation, changing the gut microbiota as well 
[26].
RVGE is considered to be a relevant cause of peditric nosocomial 
diarrhhea as well. The overall incidence of RVGE in hospitalized children 
The indistinguishable clinical 
presentation of gastroenteritis 
in children, together with the 
diversity of enteropathogens, 
makes the assessment of 
individual contributions of 
enteropathogenic agents that 
may cause gastroenteritis 
more challenging. 
 T. Babić, B. Miljković-Selimović, D. Đorđević-Stanković et al.The incidence of rotavirus infection compared to bacterial infections in different age groups...
© Inštitut za sanitarno inženirstvo, 201950
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in Europe is from 31% to 87% of nosocomial diarrhea [27]. One 
investigation in Poland (2006–2010) revealed that the mean proportion 
of nosocomial RVGE among all rotavirus infections was 24%, with the 
highest rates in children younger than two years [27, 28]. In the 
investigated period, we did not find any nosocomial infections caused 
by RV in hospitalized children. 
In a Polish study, 69% of rotavirus infections occurred in the autumn 
and winter season [29], which is similar to other data obtained for the 
temperate or subtropical regions in developed countries [25, 27]. 
However, our data indicated the highest rate of RGVE in winter/spring 
season, with its maximum in April. In Turkey, RV infection was most 
frequent in the period January – April [19]. Rotavirus cases may vary by 
geographical location: in temperate climates most cases are observed 
in fall, winter and spring months [11], while in tropical countries there 
are not seasonal peaks [12]. However, in Burkina Faso among the 
children under five years of age, rotavirus infections occur more often in 
the dry season when compared to the wet season (p = 0.03) [30].
Although viral etiology of GE can be recognized using numerous simple 
and fast tests based on ELISA and immunchromatography, due to 
which unnecessary antibiotic use is thus avoided, molecular PCR-based 
techniques can be used to improve the overall diagnostic efficacy of 
viral and bacterial GE and to detect types and subtypes, which should 
promote various types of studies. 
CONCLUSION
Although our study was not a case–control study, our investigation 
provided some important data on the presence of enteric pathogens in 
children presenting with GE. Our data of RVGE in children, during this 
18-month research period, indicate that rotaviruses are the substantial 
factor in the etiology of acute diarrheal diseases in the town of Nis, 
Serbia, and the surrounding area, especially among hospitalized 
patients in winter and early spring season. In addition to RVGE, 
Salmonella spp. and Campylobacter spp. were the major contributors to 
childhood diarrheal illnesses in our setting.
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