Urinary tract infection (UTI) is common in children and tends to recur frequently. UTI is ranked the second most prevalent infection after upper respiratory tract infection in children ^{1, 2} . The recurrence of UTI is more widespread in girls than in boys ^{3, 4} . About 30% of children under five suffer from recurrent UTI within the first twelve months after the first occurrence ⁵ . If not treated, UTI may lead to pyelonephritis and acute morbidity when associated with abnormalities like vesicoureteral and reflux nephropathy in children. In the long run, UTI may result in parenchymal scarring, hypertension, decreased renal function and renal scarring ^{6, 7} . For that reason, UTI is a significant contributor to mortality and morbidity in children. However, when recognized and appropriately managed, renal sequelae are rare.

UTI occurs in 2.4-2.8% of children in the United States annually ⁸ . The incidence of UTIs is mostly influenced by the host factors such as age and gender. Other risk factors are congenital genitourinary conditions, immature host defenses, lack of circumcision in boys, malnutrition, social status, prior history of UTI, instrumentation, the existence of abnormal urinary tract and the extent of virulence of the etiological agent ^{7, 9– 11} . In both boys and girls, the prevalence of UTI is high in the first twelve months of life and decreases after that ⁵ . Shaikh and colleagues reported a UTI prevalence of 7.0% in infants with fever ¹² . In febrile infants aged 0–2 months, UTI prevalence in girls and uncircumcised boys was 5% and 20%, respectively ¹² . In the first six months, the risk of UTI was 10 to 12 higher in uncircumcised boys ⁷ . Estimates show that about 7.8% of girls and 1.7% of boys develop UTI by the age of seven. At sixteen years of age, 11.3% of girls and 3.6% of boys may suffer from UTI ⁷ .

A prompt diagnosis and appropriate treatment are essential to reduce the morbidity and sequelae following a UTI ¹³ . However, diagnosis of UTI in children under two years is usually confounded by the non-specific signs and symptoms of UTI ⁹ . Children with uncomplicated UTI may respond to amoxicillin, sulphonamides, trimethoprim-sulfamethoxazole or cephalosporins, concentrating in the lower urinary tract ¹⁴ . Several studies show similar efficacy among the oral and intravenous antibiotics for UTI treatment ¹⁵ . However, studies in high-income countries suggest that UTI causative bacteria increase acquiring resistance to commonly used antibiotics, such as trimethoprim-sulfamethoxazole ^{16, 17} .

Gram-negative organisms highly contribute to the proportion of uropathogens isolated from children with UTI ^{6, 18} . Escherichia coli accounts for up to 90% of infections ⁶ . Other uropathogens commonly isolated in UTI include Klebsiella pneumoniae, Proteus mirabilis, Citrobacter, Pseudomonas aeruginosa, Enterobacter aerogenes, Enterococcus species and Serratia species ¹⁸ . Proteus mirabilis is more commonly found in boys compared to girls ¹⁹ . Streptococcus agalactiae is commonly isolated from newborns ²⁰ . Staphylococcus saprophyticus is isolated in sexually active female adolescents and contributes to 15% of UTI cases ²¹ .

Malnutrition is a major risk factor for child mortality and adult ill-health. Malnutrition could increase the risk of serious infections ²² . Malnutrition is still a problem Bagamoyo district in Tanzania due to poor living conditions among people living within and around Bagamoyo ²³ . The living condition may predispose an individual to acquire a UTI. However, the association between malnutrition and the acquisition of UTI has not been studied in this setting. This study was undertaken to determine the prevalence of UTI, antibiotic susceptibility testing of uropathogens and assess the association between UTI acquisition and nutritional status among children under five attending Bagamoyo District Hospital in Tanzania.

A total of 214 urine samples were obtained from children aged between 12 months and 59 months who visited Bagamoyo District Hospital (see Underlying data ²⁸ ), including 123 females and 91 males ( Table 1). Demographic data were available for all the 214 participants, while the laboratory analysis was only done for the 35 samples that tested positive for urinary tract infection.

The mean age was 27.1 months. The majority of the children (37.8%) were in the age range 13-24 months, followed by 37.3% in the age range 25-36 months ( Table 1).

The prevalence rate of UTI among children attending Bagamoyo District Hospital was 16.4% ( Table 2).

The most common causative agent of UTI in children attending Bagamoyo district was E. coli (65.7%), followed by Klebsiella spp (17.1%) ( Table 3).

A proportion of 94.3% of the five uropathogens was resistant to ampicillin, followed by erythromycin and trimethoprim-sulfamethoxazole proportion of resistant isolate 94.3 and 91.4%, respectively ( Figure 1).

All Proteus species (100%) were resistant to ampicillin and erythromycin ( Figure 2), while for E. coli, the proportion of isolates resistant to these two antibiotics was approximately 90%.

Urinary tract infections (UTIs) are common causes of mortality and morbidity in children under five ³⁴ . In this study, the prevalence of UTI in children attending the clinic at Bagamoyo District Hospital was 16.4%. This is comparable to the 16.8% prevalence reported in a study conducted in Muhimbili National Hospital (MNH) in Tanzania by Francis and colleagues in 2010 ²⁵ . Also, in this study, 123 girls and 91 boys were involved. The prevalence of UTIs in girls and boys was 7.9 % and 8.4%, respectively. These results were quite different from previous studies at MNH, which are 18.8% and 15.0% for girls and boys, respectively ²⁵ . A study conducted in Enugu, Nigeria, found the prevalence of UTI among children under five to be 11% ³⁵ .

Of all children recruited, 81 (37.8%) were aged between 13 to 24 months and 80 (37.3%) were constituting about two-thirds of the recruited children. The age range 13-24 months had the highest rate (6.5%) of UTI, followed by 25-36 months (4.2%). The rate significantly decreased with increasing age (p-value =0.05). None of the children in the age group 49-59 months tested positive for UTI.

Even though our finding between girls and boys was insignificant, the high prevalence of UTIs in boys than in girls can be explained by the fact that most boys are not yet circumcised at this age. In another study, uncircumcised male infants less than three months of age had the highest baseline prevalence of UTI ¹² . The gender of the child and the parent or guardian's employment status was not associated with UTI positivity.

Similarly, nutritional status (e.g., taking additional meals other than breastfeeding) did not affect the UTI positivity. The mean body mass index for children who were UTI positive was 20.1, which was not statistically different from the negative UTI children with a body mass index of 20.2. In the study in Enugu, Nigeria, females were more likely than males to have UTI positive status ³⁵ . The lack of association between UTI and nutritional status was also found in another study in rural Africa ³⁶ . However, a large meta-analysis involving more than 3000 children indicated that the children with malnutrition were more likely to suffer from UTI than the healthy controls ³⁷ .

The most common causative agent of UTI in children attending Bagamoyo District Hospital was E. coli (65.7%), followed by Klebsiella spp (17.1%), Proteus spp (11.4%), Pseudomonas spp (2.9%) and Staphylococcus spp (2.9%). Similar results were reported by Aiyegoro et al., who reported Escherichia coli (57.8%) in Nigeria ³⁸ . Similar results were also reported by Bahati et al., who reported that 70% of isolates were Escherichia coli conducted at Bugando Medical Center in Mwanza, Tanzania ³⁰ . In Turkey, similar results were obtained ³⁹ , where E. coli was the most prevalent uropathogen with an isolation rate of 64.2%. In Enugu, Nigeria, the organisms isolated from the 22 positive urine cultures were E. coli 31.8%, Staphylococcus aureus 22.7%, Klebsiella species 13.6%, Proteus species 4.55% and Pseudomonas species 4.55% ³⁵ . In another study in Nigeria, the isolation rate of E. coli was 37% ⁴⁰ , indicating higher isolation rates of E. coli in the current study.

In this study, seven antibiotics were used to study the antibiogram of uropathogens isolated from urine samples in children under five, namely amoxicillin-clavulanate, ceftriaxone, ampicillin, erythromycin, nalidixic acid, trimethoprim-sulfamethoxazole and nitrofurantoin. The overall percentage of isolates' resistance was high for ampicillin 93.4%, erythromycin 93.4%, trimethoprim-sulfamethoxazole 91.4%. The resistance was relatively less in nalidixic acid 40%, amoxicillin-clavulanate 34.3%, nitrofurantoin 34.3 and ceftriaxone 17.1%. Therefore, the isolated uropathogens showed high in-vitro resistance to ampicillin, erythromycin, and trimethoprim-sulfamethoxazole. At least 90% of five uropathogens in the 35 positive samples were resistant to these antibiotics. These resistance levels are much higher than reported in a study comprising of 17,164 urine cultures ⁴¹ , where the antimicrobial resistance rates were: ampicillin 36.3%, amoxicillin/clavulanic acid 24.7%, cefuroxime 16.8%, co-trimoxazole 31.1%, ciprofloxacin 14.7%, fosfomycin 14.5%, nitrofurantoin 15.6% and 3rd generation cephalosporins 9–11% ⁴¹ .

On focusing on the antibiogram of all 23 E. coli isolates in this study, the resistance rate to antibiotics was ampicillin 91.3%, erythromycin 91.3%, trimethoprim-sulfamethoxazole, 91.3%, nalidixic acid 39.1%, amoxicillin-clavulanate 34.8%, nitrofurantoin 30.4% and ceftriaxone 17.4%. These findings were comparable to the findings reported by Bahati et al., conducted in Mwanza Tanzania ³⁰ . In another study conducted in northwestern part of Tanzania, resistance rates of E. coli were ampicillin (98.4%), trimethoprim-sulfamethoxazole (95.3%), amoxicillin-clavulanate (87.5%), cephalexin (61%), cefaclor (43.8%), gentamicin (21.9%), ceftriaxone (14%), nitrofurantoin (12.5%), ciprofloxacin (11.6%), ceftazidime (11%) and cefepime (3.1%) ⁴² . The antibiogram of E. coli was similar to that observed in a study in Turkey ³⁹ .

The prevalence of UTIs for children under the age of five in this study was 16.4%. Escherichia coli was the most common bacteria in UTIs, followed by Klebsiella spp. There was high in-vitro antibacterial resistance to ampicillin, trimethoprim-sulfamethoxazole and erythromycin with Proteus, Pseudomonas and Klebsiella species highly resistant to these three antibiotics. There was no association found between malnutrition status and the UTI.

These findings imply that children under five attending health facilities should be evaluated for UTI. Due to high resistance patterns of erythromycin, ampicillin and trimethoprim-sulfamethoxazole, these agents' routine use for treating UTIs in children under five should be evaluated at the health care facility. These agents need to be used following susceptibility testing results. Therefore, continuous surveillance for antimicrobial stewardship and surveillance is required to curb the increasing resistance patterns of uropathogens to manage UTI and other infections successfully.