Treatment of Salmonella gastroenteritis in infants. The significance of bacteremia

Non-typhoidal Salmonella infections in children: Review of literature and recommendations for management

Non-typhoidal Salmonellae are a major cause of infectious diarrhoea worldwide and can cause invasive diseases, including bacteraemia, meningitis and osteomyelitis. Young or immunocompromised children and those with underlying conditions such as sickle cell disease are particularly vulnerable to invasive disease. There has been an increase in the rate of resistant non-typhoidal Salmonella, which is associated with invasive disease and hospitalisation. The intracellular nature of non-typhoidal Salmonella protects against extracellular antibiotics and can facilitate disease relapse, particularly meningitis. Effective antimicrobial agents with good intracellular penetration include azithromycin, fluoroquinolones and third-generation cephalosporins. Antibiotic treatment of non-typhoidal Salmonella gastroenteritis is only indicated if there are risk factors for invasive disease as it can prolong excretion and does not shorten the duration of gastrointestinal symptoms. Optimal choice and length of therapy for gastroenteritis and invasive disease in children is not clear. Here, we provide a review of the literature and treatment recommendations.

Nontyphoidal Salmonella bacteremia in previously healthy children: analysis of 199 episodes

BACKGROUND

Nontyphoidal Salmonella (NTS) bacteremia is not rare in otherwise healthy children in Taiwan. Few studies described the clinical manifestations and outcomes of NTS bacteremia in previously healthy children.

METHODS

Children with blood culture positive for NTS treated at Chang Gung Children's Hospital between May 1996 and June 2003 were identified from the microbiology logbook. Patients who had underlying events or concomitant diseases were excluded.

RESULTS

We evaluated 199 patients. One hundred and eighteen (59.3%) were male children and 184 (92.5%) were between 3 months and 5 years of age. Fever (97.0%) and diarrhea (79.9%) were the most common initial presentations. Leukocytosis (leukocyte >15,000/mm) and elevated serum C-reactive protein concentration (> or =10 mg/L) were present in 14.6% and 79.4% of the patients, respectively. Eighty-three percent of 184 patients with antibiotic treatment received a third- or fourth-generation cephalosporin as definitive antibiotic therapy. Focal suppurative infections were present in 5 children (2.5%) on initial evaluation, and included meningitis in 2 and osteomyelitis in 3. Neither metastatic complications nor clinically recurrent diseases were found during a follow-up period of at least 12 months after treatment. No fatalities occurred in this series.

CONCLUSIONS

In healthy children, NTS bacteremia was relatively benign and extraintestinal focal suppurative infections were infrequently seen. Less than 10 days of appropriate antibiotic treatment is probably adequate for those without a suppurative focus of infection.

Invasive non-typhoidal salmonellosis in immunocompetent infants and children

OBJECTIVE

To investigate the extraintestinal manifestations of non-typhoidal Salmonellae (NTS) infection in immunocompetent infants and children.

METHOD

The study took place at the University General Hospital at Heraklion, Crete. Over a 10-year period from 1993-2002 we studied 1087 patients, of whom 443 were children less than 14 years old, with a culture-proven diagnosis of NTS infection. Stool and blood cultures were routinely obtained in patients presenting with fever and diarrhea. The cases of invasive infection in otherwise well children, including bacteremia and/or extraintestinal focal infections were further analyzed.

RESULTS

Invasive cases were less common in children than adults (4.06% vs. 8.7%; relative risk 0.467; 95% confidence intervals (CI) 0.279-0.784; p=0.0033). Furthermore, invasive cases were much less common in the otherwise well than in immunocompromised children (3.5% vs. 21.4%; relative risk 0.163; 95% CI 0.053-0.500; p=0.0008). The 15 otherwise well children with invasive NTS infection were aged from 3 weeks to 7.5 years, and nine were aged less than 12 months. Among them, 11 presented with bacteremia, and four with focal extraintestinal infections (rectal abscess, deep neck abscess, urinary tract infection, elbow arthritis). Salmonella enterica subsp. enterica serovars Enteritidis and Virchow were the most common invasive serotypes. All invasive strains were susceptible to beta-lactams including ampicillin, and to cotrimoxazole. All patients made a complete recovery with intravenous antibiotics and did not present with relapses or major infections during long-term follow-up.

CONCLUSION

Invasive non-typhoidal salmonellosis in immunocompetent children is less frequent than in both immunocompromised children and in adulthood. However, invasive cases may well occur in otherwise healthy children, especially during infancy. In these patients, prompt appropriate treatment leads to favorable outcomes.

Non-Typhi Salmonella gastroenteritis in children presenting to the emergency department: characteristics of patients with associated bacteraemia

The records of children with Salmonella gastroenteritis only (n = 97), and those with associated bacteraemia (n = 64), seen in one medical centre during a 12-year period, were analysed retrospectively. Mean patient age was 2.24 +/- 2.8 years (range, 0.05-16 years), and 49% were male. Children with bacteraemia presented after a longer duration of symptoms (7.0 +/- 6.9 vs. 3.9 +/- 4.6 days, p 0.0002), and had higher erythrocyte sedimentation rates (45 +/- 22 vs. 33 +/- 22 mm/h, p < 0.02) and lactate dehydrogenase values (924 +/- 113 vs. 685 +/- 165 IU/L, p 0.001). There was a trend in bacteraemic children towards immunosuppression (6.3% vs. 1.0%, p 0.08) and a lower number of siblings (2.9 +/- 1.9 vs. 3.8 +/- 2.7, p 0.063). Non-bacteraemic children had a more severe clinical appearance, and a higher percentage had a moderate to bad general appearance (51.5 vs. 29.7%, p < 0.01), with dehydration (37.1 vs. 18.8%, p 0.02) and vomiting (58.8 vs. 39.0%, p 0.02). Laboratory dehydration indicators were also markedly worse in non-bacteraemic children, with urine specific gravity of 1020 +/- 9.4 vs. 1013 +/- 9.0 (p 0.0002), base excess of - 4.2 +/- 3.0 vs. - 2.5 +/- 3.4 mEq/L (p 0.01), and blood urea nitrogen of 10.1 +/- 7.0 vs. 7.4 +/- 4.5 mg% (p 0.002). Thus, the clinical presentation of bacteraemic children was more gradual, and associated gastroenteritis and dehydration was less pronounced. These findings may contribute in part to the inadvertent discharge of bacteraemic children from the emergency department.

Important bacterial gastrointestinal pathogens in children: a pathogenesis perspective

This article focuses on the five most common bacterial enteropathogens of the developed world--Helicobacter pylori, Escherichia coli, Shigella, Salmonella, and Campylobacter--from the perspective of how they cause disease and how they relate to each other. Basic and recurring themes of bacterial pathogenesis, including mechanisms of entry, methods of adherence, sites of cellular injury, role of toxins, and how pathogens acquire particular virulence traits (and antimicrobial resistance), are discussed.

Nontyphoid salmonellosis in taiwan children: clinical manifestations, outcome and antibiotic resistance

OBJECTIVES

The purposes of this study were to investigate the epidemiologic, clinical, and microbiologic features of patients with nontyphoid salmonellosis and to elucidate the impact of resistance on the outcome of nontyphoid salmonellosis in Taiwan. The authors also sought to develop a severity score to derive an objective guideline for antibiotic use in nontyphoid salmonellosis in the era of increasing antibiotic resistance.

METHODS

The authors prospectively monitored 311 children with nontyphoid salmonellosis in Kaohsiung, Taiwan. The demographic, clinical, and microbiologic features, underlying diseases, treatment regimen, complications, and outcome were analyzed. In vitro susceptibility testing of the isolates was performed.

RESULTS

The median age of affected patients was 15 months. Salmonella enteritidis B caused 68.5% of episodes, followed by S. enteritidis C1 (11.9%), D (7.7%), C2 (7.1%), E (2.6%), S. choleraesuis (1.6%), and S. paratyphi (0.6%). Sixty percent of isolates were resistant to ampicillin. Patients with bacteremia could not be differentiated from patients without bacteremia on clinical grounds. Patients receiving antibiotics that were inactive in vitro (discordant therapy) had more days of fever and longer hospital stay compared with patients receiving antibiotics that were active in vitro (concordant therapy). Patients receiving no antibiotic treatment had the fewest days of fever and shortest hospital stays, especially among patients with mild illness (severity score, 0-1).

CONCLUSION

Blood culture should be obtained in patients with nontyphoid salmonellosis to detect bacteremia. In treating antibiotic-resistant nontyphoid salmonellosis, antibiotics are still not mandatory for patients who present with primarily gastrointestinal symptoms and limited signs of systemic inflammation reflected by a low severity score (low C-reactive protein, fewer band cells in peripheral blood, and fewer days of fever before admission). Susceptibility data should be promptly obtained because use of discordant antibiotics appears to prolong illness.

Systemic nontyphoidal Salmonella infection in normal infants in Thailand

BACKGROUND

The relative paucity of information about systemic nontyphoidal Salmonella (NTS) infection in infants without an underlying disease prompted this study.

METHODS

Infants without an underlying disease, who had positive cultures for NTS from their normally sterile sites during 1978 through 1998, were included. Their medical records were reviewed.

RESULTS

The study included 75 eligible infants; 68 (91%) had positive blood cultures. The spectrum of disease included transient bacteremia (5), bacteremia without localized infection (37), bone and joint infection (5) and meningitis (28); 53 and 88% of infants were < or =3 and < or =6 months old, respectively. All infants with localized infection were < or =7 months old, and infants with meningitis were 3.35+/-1.87 (mean +/- SD) months old. In bacteremic infants risks for localized infection and meningitis were 30 and 24%, respectively. Abnormal neurologic findings were the only predictor for meningitis. Relapse of meningitis occurred in two infants despite treatment with cefotaxime for 4 and 6 weeks. Severe neurologic deficit occurred in 21% of infants with meningitis. Of 11 infants with meningitis who received early treatment at this tertiary care center, 1 died but none had severe neurologic deficits; whereas of 17 referred cases, 2 died and 6 had severe neurologic abnormalities. No death occurred in infants without meningitis.

CONCLUSION

Systemic NTS infection in normal infants has a variable disease spectrum. Infants 0 to 6 months of age are at high risk for localized infection, especially meningitis.

Multiple brain abscesses caused by Salmonella typhi: case report

BACKGROUND

Focal intracranial infections caused by Salmonella species are uncommon. The authors report a case of multiple brain abscesses caused by Salmonella typhi.

CASE DESCRIPTION

A 2-month-old girl was admitted to the hospital because of diarrhea, vomiting, fever, and poor feeding. Neurological examination revealed cervical hyperextension and absence of sucking and Moro reflexes. During the next 20 hours she developed complex partial seizures with secondary generalization and alternated irritability with drowsiness. Investigation showed hemoglobin 6.3 g/dl; white blood cell count of 19500/mm3 with a marked shift to the left. The analysis of the cerebrospinal fluid revealed white cell count of 1695/mm3, lymphocytes 61%, protein 300 mg/dl and glucose 6 mg/dl. The patient was treated for acute gastroenterocolitis, sepsis, and meningitis. Blood culture taken on the day of admission showed gram-negative bacilli, later identified as S. typhi. Computed tomography scan demonstrated a lesion in the right parietal lobe compatible with a brain abscess. Follow-up computed tomography after 7 days showed several other lesions with the same features. Surgical drainage of the right parietal lesion was performed on the 13th day, through a burr hole. The patient was discharged 5 weeks after admission without neurological deficit.

CONCLUSION

Bacteremia, sepsis, and meningitis are relatively common in children with Salmonella infection but intracranial abscesses are very rare. Surgical drainage combined with prolonged antibiotic therapy (drug of choice: chloramphenicol) is the best treatment for Salmonella brain abscesses. The possibility of intracranial infection should be considered in patients with Salmonellosis and neurological dysfunction.

Occult bacteremia in young febrile children

The evaluation of nontoxic-appearing, young, febrile children has been a subject of considerable debate. Of young, nontoxic-appearing children aged 3 to 36 months with temperatures of 39 degrees C or more and no clear source, approximately 2% to 3% have occult bacteremia. Of these bacteremias, approximately 90% are caused by S. pneumoniae, 5% by nontyphoidal Salmonella sp., and 1% by N. meningitidis. Most children with occult pneumococcal bacteremia improve spontaneously, but approximately 25% of untreated patients have persistent bacteremia or develop new focal infections, including 3% to 6% who develop meningitis. Occult meningococcal bacteremia, although rare, has frequent complications, including meningitis in approximately 40% and death in approximately 4%. Less is known about the natural history of untreated occult nontyphoidal Salmonella bacteremia. Empiric antibiotic treatment of children with occult bacteremia decreases the rate of complications, including meningitis. Few disagree that febrile, young children at risk for occult bacteremia require a careful clinical evaluation and close follow-up. The benefits of laboratory screening and selective empiric antibiotic treatment of febrile children at risk for occult bacteremia have to be weighed against the costs of screening tests and blood cultures, inconvenience, temporary discomfort to patients, risk for side effects of antibiotics, and the role of antibiotics in the development of bacterial resistance. Although great debate exists concerning the role of empiric antibiotics, a strategy for obtaining blood cultures and empirically administering antibiotics on the basis of an increased ANC, in addition to close clinical follow-up, may be effective in reducing the frequency and severity of uncommon but adverse sequelae. A highly effective S. pneumoniae bacterial conjugate vaccine will soon be available, which will benefit all children, and will alter the ways that clinicians evaluate fully immunized young, febrile children.

Non-typhi Salmonella bacteremia in children

BACKGROUND

Non-typhi Salmonella (NTS) infections are a frequent cause of self-limited diarrheal illness in healthy children. Bacteremia is a known complication of NTS infection, but the management of children with bacteremia has been based on limited data.

OBJECTIVE

To study the outcomes of pediatric patients with NTS bacteremia.

METHODS

Retrospective review of patients with NTS bacteremia covering a 16-year period at an urban pediatric hospital. Clinical data from the initial visits and any follow-up visits or hospitalizations were abstracted from the medical record.

RESULTS

We studied 144 patients. Median age was 10.5 months. Fifty-four patients were hospitalized at the initial visit including all the patients with immunodeficiency (n = 12). Of the 90 patients initially managed as outpatients, 79 were subsequently admitted; only 1 of these patients developed a focal complication. Persistent bacteremia was found in 51 (41%) patients. Among nonimmunocompromised patients, persistent bacteremia was noted in 34% [95% confidence interval (CI), 20 to 52%] of those initially treated with oral antibiotics, 52% (CI 30 to 74%) of those initially treated with a parenteral dose of antibiotics and in 31% (CI 22 to 43%) of those who were not initially given antibiotics. No laboratory or clinical factors predicted persistent bacteremia. Twelve patients developed focal infections: 3 of 119 previously healthy children (2.5%, CI 0.5 to 7%); and 9 of 25 children with underlying medical conditions (36%, CI 19 to 57%). Focal infections included meningitis (3), osteomyelitis (4), septic arthritis (2), pneumonia (2) and cholangitis (1).

CONCLUSIONS

NTS bacteremia occurs in otherwise healthy children, although the risk of focal infections is small. Patients with NTS bacteremia frequently have persistent bacteremia at follow-up regardless of initial antibiotic treatment.

Salmonella enteritidis orchitis in a 10-week-old boy

Extraintestinal manifestations of salmonellosis in paediatric patients are found predominantly in infants less than three months of age. Genital involvement is a rare complication. We present a short review of the literature and describe the case of a 10-week-old boy suffering from severe diarrhoea, who presented with a swelling of the right testicle after six days of illness. He underwent surgery on suspicion of testicular torsion, whereby orchitis was diagnosed. Salmonella enteritidis was cultured from the intraoperative swab. All cultures from blood, CSF and urine remained sterile. We conclude that orchitis must be taken into consideration as an extraintestinal complication of enteric salmonellosis and as a differential diagnosis of testicular torsion. In addition, we wish to emphasize that any infant less than three months of age with suspected or proven salmonellosis, should receive early antibiotic treatment.

Acute infectious diarrhea

Diarrhea continues to be a major cause of mortality and morbidity in third world countries as well as a major symptomatic complaint in the primary care setting in the United States. The etiologic pathogen depends on an exposure history to include recent travel to foreign countries, consuming fecally contaminated water or food, prior use of antibiotics, or homosexual behavior. A careful history from patients directed at attempting to identify particular risk factors may help in making a diagnosis. Not all patients require a diagnostic workup. A large number of patients may only require oral rehydration, careful observation over time with or without use of antimotility agents. In toxic appearing patients or patients with fever, however, bloody stools, abdominal pain or tenesmus, a selective diagnostic workup is indicated. Antimicrobial treatments are not always required, some pathogens clearly call for treatment while some have less clear indications and other pathogens are not responsive to antimicrobial agents at all. Finally, one needs to remember that the differential diagnosis of acute diarrhea includes many noninfectious origins.

Common clinical features as predictors of bacterial diarrhea in infants

Identification of infants with bacterial diarrhea during the first year of life is important to limit potentially serious complications, but indications for stool leukocyte examination and culture are not well defined. The ability of three clinical features--temperature, history of blood in the stool, and stool frequency--to predict the presence of bacterial gastroenteritis was analyzed. Over a 1-year period, 108 (10.4%) bacterial pathogens were isolated from 1,035 infants aged less than 1 year with diarrhea. Bacterial culture was positive in 14.9% of cases from May to October, compared with 6.2% of cases from November to April. A history of blood in the stool was the best individual predictor with sensitivity of 39%, specificity of 88%, and a positive predictive value of 30%. Temperature greater than 39 degrees C had sensitivity of 34% and specificity of 85%; greater than or equal to 10 stools in 24 hours had sensitivity of 28% and specificity of 85%. Using combinations of factors, we identified (1) a group of patients at high risk for bacterial diarrhea (infants with two of the three factors studied); (2) a low-risk group (those with temperature less than or equal to 38 degrees C, less than 10 stools in 24 hours, and the absence of blood in the stool); and (3) a group at intermediate risk for bacterial diarrhea (all other patients). We recommend routine stool cultures for infants with a high-risk combination. Additional clinical and laboratory features, such as stool leukocytes, should be studied among patients in the intermediate-risk group.

Perioperative dissemination of Salmonella

A hypophyseal adenoma was operated on in a patient who was a carrier of Salmonella typhimurium. A chronic salmonella osteitis developed in her calvarium at the site of operation. Our case and reported experience emphasise that asymptomatic carriers of salmonella should be given perioperative antibiotic prophylaxis, especially if they are immunosuppressed.