Antibody response to Arcanobacterium haemolyticum infection in humans

Prevention of enteric bacterial infections and modulation of gut microbiota with conjugated linoleic acids producing Lactobacillus in mice

Probiotics are recognized for outcompeting pathogenic bacteria by competitive receptor-mediated colonization and secretion of functional metabolites which are antimicrobial against certain microbes as well as improving host's gut health and immunity. Recently, we have constructed a bioactive Lactobacillus casei (LC) strain, LC^+mcra , by inserting mcra (myosin cross-reactive antigen) gene, which stimulates the conversion of conjugated linoleic acids. In this study, we evaluated the modulation of gut microbiome and protective roles of LC^+mcra against pathogenic Salmonella enterica serovar Typhimurium (ST) and enterohemorrhagic E. coli (EHEC) infections in BALB/cJ mice. We observed that LC^+mcra colonized efficiently in mice gut intestine and competitively reduced the infection with ST and EHEC in various locations of small and large intestine, specifically cecum, jejunum, and ileum (p < 0.05). Positive modulation of the cecal microbiota, for example, higher relative abundances of Firmicutes, lower relative abundances of Proteobacteria, and increased bacterial species diversity/richness, was detected in ST-challenged mice pretreated with LC^+mcra based on 16S metagenomic sequencing. Cytokine gene expression analysis indicated that mice pretreated with LC^+mcra associated with attenuated bacterial pathogen-induced gut inflammation. Furthermore, mice fed daily with LC^+mcra for one week could protect themselves from the impairments caused by enteric infections with ST or EHEC. These impairments include weight loss, negative hematological changes, intestinal histological alterations, and potential death. This in vivo study suggests that daily consumption of novel conjugated linoleic acids over-producing probiotic effectively improves intestinal microbiota composition and prevents/combats foodborne enteric bacterial infections with pathogenic Salmonella and diarrheagenic E. coli.

Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America

The guideline is intended for use by healthcare providers who care for adult and pediatric patients with group A streptococcal pharyngitis. The guideline updates the 2002 Infectious Diseases Society of America guideline and discusses diagnosis and management, and recommendations are provided regarding antibiotic choices and dosing. Penicillin or amoxicillin remain the treatments of choice, and recommendations are made for the penicillin-allergic patient, which now include clindamycin.

Systemic and deep-seated infections caused by Arcanobacterium haemolyticum

Arcanobacterium haemolyticum has been implicated mainly in non-streptococcal pharyngitis and wound infections. Rarely, it has been reported to cause systemic infection, often in combination with other pathogens. Two cases of systemic and deep-seated infections caused by Arcanobacterium haemolyticum are reported, and the literature is reviewed. Sixteen cases of bacteremia and seven cases of non-bacteremic deep-seated have been published previously. Eight of the bacteremic and two of the non-bacteremic cases occurred in younger, apparently healthy immunocompetent patients. Six patients had infections of the central nervous system. The optimal treatment of infections caused by Arcanobacterium haemolyticum is not known. Although in vitro susceptibility tests have demonstrated tolerance of Arcanobacterium haemolyticum to penicillin, penicillins with or without aminoglycosides have been the most widely used antibiotics, in most cases with success.