Prevalence, antimicrobial susceptibility pattern and associated factors of Salmonella and Shigella among under five children with diarrhea attending Bule Hora University Teaching Hospital, Bule Hora, West Guji, Ethiopia

Abstract

Background

Salmonella and Shigella are a critical concern of the developing world and responsible for the high rate of diarrhea-related deaths. The treatment of these infections remains a challenge, due to the global rise in broad-spectrum resistance to many antibiotics. The aim of this study to determine the prevalence, antimicrobial susceptibility patterns, and associated factors of Salmonella and Shigella among under five children with diarrhea attending Bule Hora University Teaching Hospital, Bule Hora, West Guji, Ethiopia.

Methods

A hospital-based cross-sectional study was conducted from July 01 to October 30, 2023. Three hundred sixty-five under five children with diarrhea were enrolled consecutively using convenient sampling technique. Data about patient socio-demographics, signs, and symptoms was obtained from the parents/guardians of each child using a questionnaire. Stool specimens from diarrheic children were collected and processed for isolation of Salmonella and Shigella using standard bacteriological methods. Antibiotic susceptibility patterns were determined by using the Kirby Bauer disc diffusion method. Data analysis was performed by using SPSS version 25. A p-value < 0.05 at 95% CI was considered statistically significant.

Results

The prevalence of salmonella and Shigella isolates were 6.3% (23/365) and 4.9% (18/365) respectively. The isolates were 95.1% susceptible to ciprofloxacin and 73.2% to ceftriaxone. The isolates were 39.02% multidrug resistance to classes of drug choice for susceptibility tests. Presence of vomiting (AOR = 2.36), contact with diarrhoeal patient (AOR = 3.38), untrimmed fingernail (AOR = 5.20), storing cooked food in open containers (AOR = 6.5), unimproved source of drinking water from well and river (AOR = 3.86 & 3.2) showed statistically significant association with Salmonella and Shigella infections.

Conclusion

The prevalence of Salmonella and Shigella isolates were relatively high in the study area. The isolates were found to be sensitive to Ceftriaxone, ciprofloxacin, and cotrimoxazole; and could be possible antimicrobial choices of infection. Contact with diarrhoeal patients, untrimmed fingernails, storing cooked food in open containers and unimproved sources of drinking water were the main sources of infection. Therefore, to alleviate this infection, culture based bacterial species identification and promoting antibiotics sensitivity-based treatment are strongly recommended to avoid empirical treatment in the study area.

Introduction

Diarrhea is a condition of having three or more loose or liquid bowel movements per day and a major public health problem throughout the world and is responsible for high morbidity, and mortality and is the second leading cause of death in children under 5 years of age in developing countries [1,2,3]. Each year diarrhea kills around 525,000 under-five children and 12% of the estimated 3.6 million child deaths in 2010 were attributed to diarrheal diseases [3].

The most common bacterial agents of human infections in developing countries are Salmonella spp, Shigella spp, Enterotoxigenic Escherichia coli, and Campylobacter [4]. Among these agents, Salmonella and Shigella are worrisome as causes of enteric fever, food poisoning, and gastroenteritis [2, 5]. Salmonella can be divided into two major groups of clinical importance; enteric fever (typhoidal salmonellosis) and non-typhoidal salmonellosis [6]. Non-typhoidal Salmonellae particularly Salmonella enteritidis and Salmonella typhimurium, among many other serovars cause gastrointestinal infections in young children in developing countries [7]. Notably, the Shigella and Salmonella species are a critical concern of the developing world and responsible for the high rate of diarrhea-related deaths [8]. Shigella species are common cause of bacillary dysentery by the invasion and disruption of the epithelium lining the terminal ileum, colon, and rectum via the fecal–oral route, person-to-person contact, household flies, infected water, and inanimate objects [9, 10]. There are four types of Shigella spp; among these more than 90% of global shigellosis cases are caused by S. flexneri and S. sonnei [11,12,13,14].

Salmonella and Shigella infections are associated with poor access to a good latrine, poor environmental sanitation, and hygienic status like; hand washing habit and fingernail status, consuming unimproved water and storing food condition [15, 16]. Different studies have reported that Shigella were associated with majority of cases of bacillary dysentery mainly in developing nations and a prominent global cause of moderate to severe diarrhea [17,18,19]. The rates of Shigella and Salmonella in Ethiopia reported from different studies are in the range of 1.6%%–10.7% and 1.6%–12.6%, respectively [15, 20,21,22]. Under the age of five children face the biggest impact of the disease and 61% of deaths occur [23]. Previous reports indicate that using water from unimproved source [24, 25], storing cooked food in an open container [26], untrimmed fingernail leading to infection with Salmonella and Shigella [15, 22].

In addition, treatment of these infections remains a challenge, due to the global rise in broad-spectrum resistance to many antibiotics. Antibiotic resistance has been increasing the risk of morbidity, mortality and economic burden [27, 28]. One reason for increasing antimicrobial resistance is the unrestricted use of over-the-counter drugs without medical supervision [8]. Dissemination of Salmonella and Shigella strain resistance to ampicillin, chloramphenicol, tetracycline and co-trimoxazole are increasingly documented in developing countries [26]. In 2020, Shigella and Salmonella infections were resistant to at least one antibiotic used to treat the severe infection [29]. Antimicrobial-resistant is one of the public health problems in present-day clinical practices [30]. Empirical prescription of antibiotics by treating physicians is common in Ethiopia due to the lack of microbiological laboratory facilities to test antimicrobial susceptibilities [31].

As a result, there is a less awareness of antibiotic resistance on the most common etiologies of diarrhea, Salmonella and Shigella species in community. The effective management of bacterial diarrhea is to identify commonly circulating species of these bacteria, their antibiotic susceptibility pattern and associated factors in community [19]. Hence, this investigation aimed to assess the magnitude, antibiotics susceptibility pattern and associated factors of Salmonella and Shigella species from children with diarrhea who visited Bule Hora University Teaching Hospital, west Guji, Ethiopia from July 01 to October 30, 2023.

Methods and materials

Study design, area and population

A cross-sectional study was conducted from July to October 2023 among under the age of five children with diarrhea attended the Bule Hora University Teaching Hospital, West Guji, Ethiopia. Bule Hora is the capital city of West Guji Zone, far from Addis Ababa 476 km away from the center of the country. The 2007 national census reported a total population of 27,820 for Bule Hora Town, of whom 14,519 were men and 13,301 were women, 6,507 households, and 6,246 housing units were counted [32]. The hospital was established in 1990 E.C and largest one in the West Guji Zone and provides healthcare services to over 1.3 million catchment population. It serves as a teaching, training and clinical service center. The under-five out-patient department (OPD) of hospitals serve were an average of 30 children per/day (Data from the Human Resource office and record book of Bule Hora University Teaching Hospital).

Inclusion and exclusion criteria

All diarrheic under-five children ≥ 6 months of age attend the Bule Hora University Teaching Hospital were included and who had taken an antibiotic in the past 2 weeks before specimen collection and those treating for the current diarrhea attack were excluded from the study.

Sample size and sampling technique

The sample size was determined using a single population proportion formula with the following assumptions. The proportion of the problem was selected from the estimated prevalence of Shigella and Salmonella from the previous study 17.45% [15]. Accordingly

$$\text{n}=\frac{{\left(Z{\alpha /}_{2}\right)}^{2}P(1-P)}{{d}^{2}}$$

p = Prevalence of Shigella and Salmonella (17.45%)

$Z{\alpha /}_{2}$= confidence interval (1.96)

d = marginal error (4%)

$$\text{n}=\frac{{\left(Z{\alpha /}_{2}\right)}^{2}P(1-P)}{{d}^{2}}=\frac{{\left(1.96\right)}^{2 }0.1745(1-0.1745) }{{0.04}^{2}}=\frac{3.84\times 0.144}{0.00165}=\frac{0.553}{0.0016}=347$$

Finally, by considering a 10% (34.7 subjects) non-response rate, the final sample size is determined as $\approx 382$

Sampling technique

Consecutive study participants having diarrhea were recruited using convenience sampling technique.

Data collection

Using the pre-tested and structured questionnaire; socio-demographic and clinical data were collected after informing the parents/caregiver about the aim of the study. A face-to-face interview was conducted to collect the data from parents or caretaker of the children who complained of diarrhea after they signed the consent and the child accepted the assent.

Stool sample collection

The assent form was given to mother/caregiver of children to read/read for them/about aim of the study. Parents or caregivers of children was informed to bring stool samples of their children. A clean, dry, and leakproof stool cup and a clean wooden applicator stick was given for stool specimen collection. The attendant was informed to bring approximately two grams of semi-formed stool or 2 mL watery stool sample by using a coded disposable plastic cup. Bloody or mucoid parts of stool sample were collected by using a clean wooden applicator stick into a coded disposable plastic cup. The stool samples were transported within two hours at icebox [33] to Bule Hora Teaching Microbiology Laboratory.

Culturing and identification

The collected stool specimen was processed for bacteriological analysis. Two grams of semi-formed stool or 2 mL watery stool sample was collected from the study participants using a coded disposable plastic cup [33]. First stool samples were inoculated onto Selenite F broth (Enrichment Medium; Oxoid Ltd) by using a sterile swab and incubated at 37 °C. Then subculture onto Salmonella-Shigella Agar (Oxoid Ltd) and MacConkey Agar (Abtek, UK) and incubated at 35 °C–37 °C for 18–24 h. After 24 h of incubation, the culture media was evaluated for the presence of bacterial growth. The growth colonies were further characterized based on colony morphology (Salmonella appears as smooth colorless colonies with/out a black center, while Shigella appears as smooth colorless colonies on MCA and SSA) [34]. The suspected colonies were smeared for gram reaction. The identification of bacteria was confirmed using a panel of biochemical tests recommended for enteric bacteria.

Biochemical tests of the isolates

For identification of Salmonella and Shigella species, all suspected colonies were inoculated onto appropriate biochemical media including Triple Sugar Iron, Lysine iron agar, Simmon’s citrate agar, motility medium, and urea. After overnight incubation, at 37^∘ C for 18–24 h [33]; the biochemical test medium were read and the exact species was identified based on biochemical character and colony morphology on the selective medium. The identification of bacteria was confirmed using a panel of biochemical tests recommended. Biochemical character of the isolates and identification were showed in flow chart (Fig. 1).

Fig. 1

Flow chart for Salmonella and Shigella identification from stool sample

Antimicrobial susceptibility testing

The Bauer-Kirby disk diffusion method (Oxoid England) was performed as recommended by the Clinical and Laboratory Standards Institute [35]. The density of the suspended inoculum was determined by comparison with the opacity standard on 0.5 McFarland solution was inoculated by swabbing onto Muller-Hinton agar and incubated for 24 h at 37 °C. Susceptibility testing of isolates was done using the single disc diffusion technique against each antimicrobial. A pure colony of isolated bacteria was mixed with normal saline to make suspension; which compare with 0.5 McFarland standard suspension for susceptibility testing and then swabbed on Mueller Hinton agar (MHA; Oxoid Ltd).

The susceptibility pattern of the isolates was determined for Ciprofloxacin (CIP; 5 μg), Chloramphenicol (C; 30 μg), Co-Cotrimoxazole (COT; 25 µg), Ampicillin (AMP; 10 µg), Ceftriaxone (CRO; 30 µg) and Norfloxacin (NOR; 30 µg). After incubation for 24 h at 37 °C, the diameter of each zone of inhibition was measured with a ruler in millimeters. The results was then interpreted according to Clinical and Laboratory Standards Institute (CLSI) [35] guidelines for antimicrobial susceptibility breaking points in 2022 and recorded as sensitive (S), intermediate (I), or resistant (R) [35]. The selection criteria of those antimicrobial agents were their activity against gram negative bacteria and the fact that all selected agents are used in the treatment of severe diarrhoea in Ethiopia [36].

Data quality control

The standardize questionnaire was prepared in English and interpreted into Afaan Oromo (local language). The quality of the questionnaire was validated by conducting a pre-test on 5% of the total sample size (19 clients) at the Malka Soda Hospital. General Standard operation procedures (SOP) [37] was followed for every procedure in the study. All aseptic techniques were applied while inoculating culture media to enhance the validity of the results. All culture media was prepared according to the Manufacturer’s instructions. The sterility of the prepared culture media was checked by overnight incubation of 5% of the media at 37⁰C. The quality of each new batch of culture medium and antimicrobial disks was checked by testing E. coli ATCC®25922, P. aeruginosa ATCC®27853^e [35] reference strains. Laboratory data handling policies and protocols were followed while recording, reporting and interpretation of results.

Data processing and analysis

Data was entered and cleaned, using Epi-data version 4.6 and then transferred to SPSS version 25.0 statistical software for data processing and analysis [22]. Data was described using descriptive statistical tools. Logistic regression models were used to identify the factors associated with Salmonella and Shigella infections. The odds ratio, 95% confidence interval was estimated and independent variables with significant association in bivariate analysis (P-value < 0.25) were included in multivariable logistic regression. In multivariable logistic regression; independent variables with P-value < 0.05 were considered statistically significant with dependent variables by using backward stepwise approach [22].

Operational definition

• ✥ Multi-Drug Resistant (MDR): defined as resistance to three or more classes of antimicrobials [38].

Results

Socio‑demographic characteristics

A total of 382 study participant were enrolled in this study with an overall response rate 365 (95.5%). Among all study participant 196 (53.7%) were male with an age range from 6 to 59 months (mean age 29.75 months ± 15.9 months) was enrolled. Regarding the residence, the study subjects 186 (51.0%) were from Urban. Concerning the children’ mother educational status most of them 334 (91.5%) were educated which was included from reading and writing to college and above level. In relation to marital status; 326 (89. 3%) was married, 22 (6.0%) divorced and 11 (3%) widowed. Among all caregivers’ or parents of the children 222 (60.8%) was housewife and the rest are having other occupational status. The family monthly income ranged from 2,000 to 10,000 with a mean of 5,133.47 ± 1894.93 Ethiopian Birr (Table 1).

Table 1 Socio demographic status of under-five children attending Paediatrics OPD of the Bule Hora University Teaching Hospital, from July 01 to October 30, 2023, Bule Hora, Ethiopia

Prevalence of Shigella and Salmonella isolates

The overall prevalence of Salmonella and Shigella among under five children with diarrhea in this investigation were 11.2% [41/365; 95% CI = 7.98-14.4%]. Among these, the prevalence of salmonella and Shigella isolates were 6.3% [23/365; 95% CI = 3.78-8.8%] and 4.9% [18/365; 95% CI = 2.7-7.16%] respectively. Most of Salmonella isolates were isolated from children those who had a fever 82.6% (n = 19), vomiting 56.5% (n = 13), watery diarrhea and onset of diarrhea less than three day 56.5% (n = 13). Similarly, Shigella isolates were mostly isolated from children those who had a fever 88.9% (n = 16), mucoid diarrhea 27.8% (n = 5) and bloody diarrhea 22.2% (n = 4) (Table 2).

Table 2 Clinical variables from under-five children attending under five OPD of the Bule Hora University Teaching Hospital, from July 01 to October 30, 2023, Bule Hora, Ethiopia

Antimicrobial susceptibility

In this study, six antimicrobials with five classes of drugs were tested for isolates showing different rates of resistance. Among all antimicrobials tested against the isolates, both Salmonella and Shigella isolates were 95.1% (n = 39) susceptible to ciprofloxacin, 73.2% (n = 30) to ceftriaxone, 56.1% (n = 23) to cotrimoxazole and 53.7% (n = 22) to norfloxacin. However, Salmonella isolates were 95.7% (n = 22) resistance to ampicillin, 39.1% (n = 9) to chloramphenicol and norfloxacin, and 26.1% (n = 6) to cotrimoxazole. Shigella isolates were resistance to chloramphenicol 33.3% (n = 6), to cotrimoxazole 38.9% (n = 7), to ampicillin 100% (n = 18) and to norfloxacin 27.8% (n = 5) (Table 3).

Table 3 Antimicrobial Susceptibility patterns of Salmonella and Shigella isolated from under children attending Bule Hora University Teaching Hospital, from July 01 to October 30, 2023, Bule Hora, Ethiopia

Multidrug resistance (MDR) patterns

Overall multidrug resistance of the isolates was 16(39.02%) with those classes of drugs; Quinolones, Cephalosporins, Sulfonamides, Penicillin, and Phenicol. About 9 (39.13%) Salmonella isolates exhibited multiple drug resistance (resistant to three and above classes of antimicrobial). Also 1 (4.34%) of salmonella isolates were resistant to five drugs. On the other hand, 7 (38.88%) Shigella isolates were resistant to three and above drugs (Table 4).

Table 4 Multidrug resistance patterns of Salmonella and Shigella isolated from under children attending Bule Hora University Teaching Hospital, from July 01 to October 30, 2023, Bule Hora, Ethiopia

Associates factors of Salmonella and Shigella isolates

In this study, prevalence of Salmonella and Shigella among under five children with diarrhea attending Bule Hora University Teaching Hospital were 11.2%, (41/365; 95% CI = 7.98–14.4%). Regarding to associate factors; the study participants, 231(63.3%) had no contact with diarrheal patient before illness and the children infected in these categories were 15 (36.6%). Concerning the availability of latrine, 309 (84.7%) had a latrine but 246 (67.4%) unimproved and 32 (78.0%) participants were affected with Salmonella and Shigella infection.

Regarding hand-wash status, 218 (59.7%) caregivers were washing their hand after defecating a child and 35.9% wash their hand with water only, 66.7% were affected with Salmonella and Shigella infection. Similarly, 347 (95.1%) caregivers washing their hand before feeding a child and 295(80.8%) were wash their child’s-hand before and after having meal; out these categories 161 (44.1%) wash their child’s-hand with soap and 13 (37.1%) were affected with Salmonella and Shigella infection. One hundred eighty-six caregivers were washing their hand after visit a toilet and 14 (34.1%) were affected (Table 5).

Table 5 Socio-demographic characteristic, clinical variables and associated factors of under-five children with diarrhea at Bule Hora University teaching Hospital, Bule Hora, Ethiopia, 2023

Concerning finger nail status, 210 (57.5%) participants trimmed their child’s-nail’s and 9 (22.0%) were affected with Salmonella and Shigella infection. The food eaten by the children before the illness was raw vegetables and overnight food, 114 (31.2%) and 100 (27.4%) respectively, bacterial infection was dominantly isolated from children who ate food at night. Most of the children enrolled in the study were who stored their food in closed containers, 260 (71.2%). Two hundred eighty-two study participants were using tap water for drinking and the children infected in these categories were 21 (51.2%) (Table 5).

Correspondingly, Salmonella and Shigella mostly isolated from who had contact with the diarrhea patient, 26 (63.4%); stored food in an open container, 28 (68.3%); unimproved latrine 27(84.4%); untrimmed nail 32(78.0%); had animal contacts, 23 (56.1%); lack of hand-wash after visit a toilet, 27(65.9%); wash-hand with water only after defecating a child and wash child-hand before and after meal, 16(66.7%), 22(62.9%) respectively.

The bivariable logistic regression analysis indicates that sex male (COR = 1.76, 95% CI = 0.89–3.49, p-value = 0.101), rural residence (COR = 1.53, 95% CI = 0.79–2.97, P-value = 0.199), mucoid diarrhea (COR = 2.19, 95% CI = 0.77–6.22, P-value = 0.141), children who had vomiting (COR = 1.55, 95% CI = 0.81–2.98 P-value = 0.184), children who had contact with diarrhea patients (COR = 3.46, 95% CI = 1.76–6.81 P-value < 0.001) were the candidate variables for multivariable analysis with p value of < 0.25 showed in (Table 5).

Similarly, caregivers who wash their child’s-hand with water only (COR = 2.23, 95% CI = 1.08–4.63, P-value = 0.030), the untrimmed finger nail of child (COR = 5.8, 95% CI = 2.68- 12.58 P-value < 0.001), stored cooked food in open containers (COR = 6.9, 95% CI = 3.41–13.9, P-value < 0.001), and children those who consumed overnight food and raw vegetables (COR = 2.96, 2.18 with p-value 0.022, 0.107) respectively, those who drank water from well and river (COR = 4.0, 3.8 with P-value = 0.001, 0.002) respectively were the candidate variables with p value of < 0.25 (Table 5).

However, in multivariate logistic regression analysis, after adjustment, children those who had vomiting (AOR = 2.36, 95% CI = 1.15 − 5.6% P-value = 0.049), children those who had contact with diarrhoeal patients were three folds chance of infection (AOR = 3.38; 95% CI = 1.42—7.7%; P = 0.005) and those who fingernail untrimmed was five folds more infected than trimmed fingernail (AOR = 5.20; 95% CI = 2.1—12.8%; P = 0.003). Similarly, practice of keeping meal in unclosed containers for later use were 6.5 folds more infected than practicing close containers user (95% CI = 2.8—15.1%; AOR = 6.5; P < 0.001) and those who use water from well and river source were 3.8 folds more infected than those who tap water user (AOR = 3.86, 3.20 95% CI = 1.24–12.0% P = 0.020) was showed a statistically significant association of Salmonella and Shigella infection with p values < 0.05 (Table 5).

The variables like; educational status of caregivers, occupational status, types of diarrheas, caregivers those who wash their child-hand with water only, lack of hand wash after visiting a toilet and before feeding a child and children those who consumed raw milk were had odds getting infection of Salmonella and Shigella showed in (Table 5).

Discussion

Globally, there are nearly 1.7 billion cases of childhood diarrhoeal disease every year [39]. Diarrhoeal disease is the second leading cause of death in under five years and responsible for killing around 525 000 children every year [40]. Highest incidences of Salmonella infections in Sub-Saharan Africa and Europe were 227 and 102 cases per 100,000 population, respectively [41].

The overall prevalence of Salmonella and Shigella among under five children with diarrhea in this investigation were 11.2% (7.9%–14.4%), which is comparable with studies conducted in Hawassa 8.6% 8.0% [26, 42], Nekemte 9.2% [43], Debre Markos 11.7% [24], Jimma 11.2%, 11.9% [36, 44], Bale Goba 11.2% [16] Mekelle 14.2% [45], Kenya 8.1% [46] and western French Guiana 9.8% [47]. It is lower than the studies conducted in Gambella refugee camps 15% [48], Bahir Dar 17.3% [49], Arba Minch town 17.45% [15], Tehran, Iran 15.9% [50]. It is higher than the studies conducted in Ethiopia; 3.8%, 4.1%, 5.04% [8, 22, 51], Kenya 5.6% [52] and Oman 5.2% [30]. This variation in prevalence might be due to differences in sample size, study period, geographical location, season, the method employed to isolate bacterial causes of diarrhea, differences of a risk factors such as proper food storage, proper cooking of vegetables and fruits and water source, socio-demographic characteristics and awareness of study participants regarding environmental sanitation or personal hygiene.

The prevalence of Salmonella among under five children with diarrhea in this investigation were 6.3% (3.78%-8.8%) which is in line with the study conducted in Ethiopia 6%, 7.1% [25, 43], Jimma 5.2% [36], Hawassa 5.4% [42], Bahir Dar 7.8% [49], China 4% [53] and Iran 7% [50]. This report is higher than the studies conducted in different parts of Ethiopia 1.8%, 2.5%, 3.15%, [22, 51, 54], Hawassa 1.6%, 0.38%, [20, 26], 1.73% in Nigeria [55]. It is lower than the study in Addis Abebe, Jimma and Arba Minch 9.7%, 10.8% and 12.6% respectively [15, 44, 56]. This might be due to differences in sample size, study period, geographical location, the method employed to isolate bacterial causes of diarrhea, differences awareness regarding to associate factors such as personal hygiene, environmental sanitation and water treatment.

In our investigations, six antimicrobials with five classes of antibiotics were tested against isolates by showing different rates of susceptible and resistance. A level of resistance of Salmonella isolates was observed for ampicillin 95.7%, this finding were in line with the study conducted in Dire Dawa 92.3% [25] and Iran 96%, 96.2% [18, 50]. However, it is lower than the study conducted in Arba Minch 100% [15] Dessie 100% [3] and higher than the study conducted in Ambo 88.9% [8], Southern Ethiopia 71.4% [57] Debre Markos 85.7% [24] and Mekelle 88.9% [45]. This could be due to the widespread nature of resistant strains, availability and handling of these drugs from drug shops/pharmacies, misuse and self-prescription of drugs may have effects.

And also Salmonella isolates were showed resistance observed against chloramphenicol and norfloxacin were 39.1%; this finding in agreement with study conducted in South East Ethiopia 34.1% [16]. Also Salmonella also revealed resistance against cotrimoxazole 26.1%; this finding is almost comparable with the study conducted in Gambella 30.8% and lesser than the study conducted in Ambo 66.7% [8, 48]. This could be due to differences in availability and handling of these drugs from drug shops/pharmacies and lack of understanding of the management of antimicrobials.

In this study, Salmonella isolates were 39% exhibited multidrug-resistant pattern (resistant to three and above class of antibiotics). In contrast to this study, comparable reported form Addis Abebe 25.4% [56] and Dire Dawa 47.4% [25]. Unlike this study, higher result reported from study conducted in Haramaya, Eastern Ethiopia 88.9% [51], from South East Ethiopia 79.3% [16], Mekelle 100% [45] and from Mozambique 79.8% [4]. And also lower result reported from study conducted in Nekemte 3.33% [43]. This augmentation may be due to the widespread nature of resistant strains, medication sharing, fake drugs, climate changes, poor-quality of drugs, misuse and self-prescription of drugs may have own effects.

Shigella poses a substantial public health threat because few cells of organisms (10–100 bacilli) are enough to elicit bacillary dysentery that may lead to Shigellosis outbreaks [25]. In this study, the prevalence of Shigella among under five children with diarrhea were 4.9% [18/365; 95% CI = 2.7-7.16%] which is in line with the study conducted in Nigeria 4.03% [58], Bale Goba 4.3% [16], Bahir Dar 4% [59], Debra Berhan 4% [60], Arba Minch 4.85% [15] 6.0% and 6.2% in Mexico, western French Guiana respectively [17, 47].

In contrast to this study, a lower rate of Shigella infection was reported from different parts of Ethiopia 1.6%, 2.1%, [22, 43] 2% and 2.6% in Iran and Nigeria respectively [18, 55]. Also higher rate of Shigella infection was reported from different part of Ethiopia 6.0%, 6.9%, 7.6%, 8.55%, 21.7% [21, 24, 26, 36, 45], rural Mozambique 10.7% [61], Northern Nigeria 32.4% [62], Iran 8.7%, 13.2% [63, 64], Asia 7.2%, 8.0% [12, 13] and 20.9% in rural Bangladesh [10]. This might be due to differences in sample size, study period, geographical location, the method employed to isolate bacterial causes of diarrhea, differences awareness regarding to associate factors such as personal hygiene, environmental sanitation and water treatment.

In our study, Shigella species revealed that, high resistance against Ampicillin(100%) which is comparable with the studies from different part of Ethiopia; Motta [22], Jimma 100%, and another study in Jimma 100% [36, 44]. Unlike this study lower result from study conducted in Ambo town 88.9% [8], in Dire Dawa 83.3% [25] and in different countries like Iran 82% [64] and India 0–68% [11]. This could be due to β-lactam resistance in Shigella to ampicillin was encoded by OXA and TEM type β-lactamases [11].

And also Shigella isolates revealed that, 38.9% resistance to cotrimoxazole, which is comparable with study conducted in Southern Ethiopia 33.3% [19], Northwest Ethiopia, 41.4% [21]. Contrast to this finding higher result reported from Jimma 66.6% [36] and Ambo town 55.6% [8]. This augmentation may be due to the widespread nature of resistant strains, medication sharing, fake drugs, climate changes, poor of quality of drugs, misuse and self-prescription of drugs may have own effects.

However, Shigella isolates 38.8% were found to be multiple drug resistant (resistant to three and above class of antibiotic). This finding is in line with the study conducted from Nekemte 33% [43]. Unlike this finding the higher result reported from Dire Dawa 57.9% [25], Jimma 53% [36], Motta town 75% [22], Debre Markos 84.2% [24], Gondar town 76% [21], Mozambique 57.8% [4] and from Asia 68.7% [13]. This could be due to the widespread nature of resistant strains, self-medication and inappropriate use of antibiotics without routine laboratory stool culture and drug susceptibility test are led to the escalation of antibiotic-resistant bacteria.

In this study, a child those who had vomiting symptom about two times a chance of having Salmonella and Shigella infections as compared to its counterpart. This finding is in line with studies study conducted in Nekemte [43]. This could be due to Salmonella and Shigella in nature affects the ileum and colon with diarrhoea, abdominal cramp and vomiting as visible clinical signs/symptoms [6]. A child those who had contact with diarrhoeal patients with last week’s were three folds more infected with Salmonella and Shigella species (P = 0.005). This finding is in line with studies conducted in Jimma [36]. This may be because contacting and eating with infected individual may increase the risk of contamination and infection.

In our study, a child those who had fingernail untrimmed was five folds more infected with Salmonella and Shigella species (P = 0.003). This finding is in line with studies conducted in Debre Markos [24], Motta Town [22], Dire Dawa [25], Arba Minch Ethiopia [15]. Bacteria are transmitted directly and indirectly through objects such as food, water, nails, fingers, etc. Compared to other parts of the hand, untrimmed fingernails harbor the most microorganisms and difficult to clean easily.

Similarly, those who store cooked food in an open container for later use are also 6.5 times in odds of getting an infection as compared to those who practice closing the container (P < 0.001). This result is in line with studies conducted in Hawassa [26] and Debre Markos Ethiopia [24]. This can be explained by the transmission of these infections by flies, cockroaches and rodents in the house and, therefore, exposing food can lead to diarrhea in children through bacterial contamination.

And also, Children those who use water from well and river were 3.8 times more likely to get infections (P = 0.020). this result is in line with the study conducted in Debre Markos [24], Dire Dawa Ethiopia [25], and Sri Lanka [65]. Drinking or using contaminated water is responsible for the transmission of infections.

This study did not differentiate Salmonella and Shigella isolate into the species level and conducted in a short period of time from July 01 to October 30. The study design (cross-sectional) which cannot rule out cause and effect relationship of associated factors which indeed require control groups. Since this is a single-site study, which is hospital-based, it is difficult to generalize the finding of this study to all under five children with diarrhea in Bule Hora town and surrounding.

Conclusion

The prevalence of Salmonella and Shigella isolates were relatively high in the study area. The isolates showed high rate of resistance to ampicillin while low resistance to cotrimoxazole, chloramphenicol and norfloxacin. The isolates exhibited a high rate of MDR pattern. The isolates were found to be sensitive to Ceftriaxone, ciprofloxacin, and cotrimoxazole; and could be possible antimicrobial choices of Salmonella and Shigella infection. In this investigation the presence of vomiting, contact with diarrhoeal patients, untrimmed fingernails, storing cooked food in open containers and unimproved sources of drinking water had association with Salmonella and Shigella infection. Therefore, to alleviate this infection, culture based bacterial species identification and promoting antibiotics sensitivity-based treatment are strongly recommended to avoid empirical treatment in the study area. Further studies that aim to differentiate serogroups and Molecular techniques are needed.