Effect of 3 Days of Oral Azithromycin on Young Children With Acute Diarrhea in Low-Resource Settings A Randomized Clinical Trial

Importance: World Health Organization (WHO) guidelines do not recommend routine antibiotic use for children with acute watery diarrhea. However, recent studies suggest that a significant proportion of such episodes have a bacterial cause and are associated with mortality and growth impairment, especially among children at high risk of diarrhea-associated mortality. Expanding antibiotic use among dehydrated or undernourished children may reduce diarrhea-associated mortality and improve growth. Objective: To determine whether the addition of azithromycin to standard case management of acute nonbloody watery diarrhea for children aged 2 to 23 months who are dehydrated or undernourished could reduce mortality and improve linear growth. Design, Setting, and Participants: The Antibiotics for Children with Diarrhea (ABCD) trial was a multicountry, randomized, double-blind, clinical trial among 8266 high-risk children aged 2 to 23 months presenting with acute nonbloody diarrhea. Participants were recruited between July 1, 2017, and July 10, 2019, from 36 outpatient hospital departments or community health centers in a mixture of urban and rural settings in Bangladesh, India, Kenya, Malawi, Mali, Pakistan, and Tanzania. Each participant was followed up for 180 days. Primary analysis included all randomized participants by intention to treat. Interventions: Enrolled children were randomly assigned to receive either oral azithromycin, 10 mg/kg, or placebo once daily for 3 days in addition to standard WHO case management protocols for the management of acute watery diarrhea. Main Outcomes and Measures: Primary outcomes included all-cause mortality up to 180 days after enrollment and linear growth faltering 90 days after enrollment. Results: A total of 8266 children (4463 boys [54.0%]; mean [SD] age, 11.6 [5.3] months) were randomized. A total of 20 of 4133 children in the azithromycin group (0.5%) and 28 of 4135 children in the placebo group (0.7%) died (relative risk, 0.72; 95% CI, 0.40-1.27). The mean (SD) change in length-for-age z scores 90 days after enrollment was -0.16 (0.59) in the azithromycin group and -0.19 (0.60) in the placebo group (risk difference, 0.03; 95% CI, 0.01-0.06). Overall mortality was much lower than anticipated, and the trial was stopped for futility at the prespecified interim analysis. Conclusions and Relevance: The study did not detect a survival benefit for children from the addition of azithromycin to standard WHO case management of acute watery diarrhea in low-resource settings. There was a small reduction in linear growth faltering in the azithromycin group, although the magnitude of this effect was not likely to be clinically significant. In low-resource settings, expansion of antibiotic use is not warranted. Adherence to current WHO case management protocols for watery diarrhea remains appropriate and should be encouraged. Trial Registration: ClinicalTrials.gov Identifier: NCT03130114.publishedVersionPeer reviewe

Virulence of invasive <i>Salmonella</i> Typhimurium ST313 in animal models of infection

<div><p><i>Salmonella</i> Typhimurium sequence type (ST) 313 produces septicemia in infants in sub-Saharan Africa. Although there are known genetic and phenotypic differences between ST313 strains and gastroenteritis-associated ST19 strains, conflicting data about the <i>in vivo</i> virulence of ST313 strains have been reported. To resolve these differences, we tested clinical <i>Salmonella</i> Typhimurium ST313 and ST19 strains in murine and rhesus macaque infection models. The 50% lethal dose (LD₅₀) was determined for three <i>Salmonella</i> Typhimurium ST19 and ST313 strains in mice. For dissemination studies, bacterial burden in organs was determined at various time-points post-challenge. Indian rhesus macaques were infected with one ST19 and one ST313 strain. Animals were monitored for clinical signs and bacterial burden and pathology were determined. The LD₅₀ values for ST19 and ST313 infected mice were not significantly different. However, ST313-infected BALB/c mice had significantly higher bacterial numbers in blood at 24 h than ST19-infected mice. ST19-infected rhesus macaques exhibited moderate-to-severe diarrhea while ST313-infected monkeys showed no-to-mild diarrhea. ST19-infected monkeys had higher bacterial burden and increased inflammation in tissues. Our data suggest that <i>Salmonella</i> Typhimurium ST313 invasiveness may be investigated using mice. The non-human primate results are consistent with clinical data, suggesting that ST313 strains do not cause diarrhea.</p></div

Qualitative and quantitative detection of <i>Salmonella</i> Typhimurium in blood, ileum, colon and mesenteric lymph nodes (MLN) of rhesus macaques.

<p>Qualitative and quantitative detection of <i>Salmonella</i> Typhimurium in blood, ileum, colon and mesenteric lymph nodes (MLN) of rhesus macaques.</p

Diarrhea, lethargy and dysentery elicited by <i>Salmonella</i> Typhimurium I77 (ST19) and D65 (ST313) in Indian rhesus macaques.

<p>Diarrhea, lethargy and dysentery elicited by <i>Salmonella</i> Typhimurium I77 (ST19) and D65 (ST313) in Indian rhesus macaques.</p

Clinical signs in rhesus macaques.

<p>Rhesus macaques infected with <i>Salmonella</i> Typhimurium I77 (ST19) or D65 (ST313) were measured for (A) Percent change in weight, and (B) Temperature (in Fahrenheit) on days 1, 3, 7, 15 and 21/22 days post infection. Blood from infected monkeys was collected on days 0, 7 and 15 and measured for (C) white blood cell (WBC) and (D) neutrophil counts.</p

Shedding of <i>Salmonella</i> Typhimurium in the feces of rhesus macaques.

<p>Following infection with <i>Salmonella</i> Typhimurium I77 (ST19) or D65 (ST313), fecal samples were collected on days 1 to 7, 9, 11, 15, 18 and 21 or 22. Data is represented as CFU per gram of feces. ** represents P < 0.01, Student’s t-test, two-tailed.</p

Bacterial load of <i>Salmonella</i> Typhimurium ST313 and ST19 in mice.

<p>CD-1 mice were infected perorally with 3 strains of <i>Salmonella</i> Typhimurium ST19 (I77, I41, S52) and ST313 (D65, Q55, S11). The number of CFUs at 3, 24, 72 and 168 h p.i. were determined in blood (A), spleen (B) and liver (C). BALB/c mice were infected perorally with <i>Salmonella</i> Typhimurium I77 and D65 and blood harvested at 3 and 24 h p.i. (D). Results are expressed as mean ± SD. *** represents P < 0.001, Student’s t-test, two-tailed.</p

Histopathology of tissues infected with <i>Salmonella</i> Typhimurium.

<p>Hematoxylin and eosin-stained sections of liver, colon, ileum and mesenteric lymph node (MLN) from rhesus macaques. The images in the left (10X magnification) and middle (20X magnification) columns are from animals infected with <i>Salmonella</i> Typhimurium I77 (ST19). Images on the right (20X magnification) are from animals infected with <i>Salmonella</i> Typhimurium D65 (ST313). Areas of necrosis and lymphocytic infiltration of the liver section from a ST19-infected animal are indicated by arrows. Tissue sections from a ST19-infected animal show areas of erosion of mucosal epithelium of the colon and ileum combined with areas of infiltration of lymphocytes and plasma cells. These areas are indicated by arrows. Granulomatous areas consisting of multinucleated giant cells in the mesenteric lymph node of the animal infected with ST19 are indicated by arrows. All sections from D65-infected animals display essentially normal histology.</p

50% lethal dose of ST19 and ST313 strains in juvenile BALB/c and adult BALB/c and CD-1 mice.

<p>50% lethal dose of ST19 and ST313 strains in juvenile BALB/c and adult BALB/c and CD-1 mice.</p

The Diversity of Lipopolysaccharide (O) and Capsular Polysaccharide (K) Antigens of Invasive Klebsiella pneumoniae in a Multi-Country Collection

10.3389/fmicb.2020.01249Frontiers in Microbiology11124