A rare case of severe gastroenteritis caused by Aeromonas hydrophila after colectomy in a patient with anti-Hu syndrome: a case report

Genomic insights into the 2022-2023Vibrio cholerae outbreak in Malawi

Malawi experienced its deadliest Vibrio cholerae (Vc) outbreak following devastating cyclones, with >58,000 cases and >1700 deaths reported between March 2022 and May 2023. Here, we use population genomics to investigate the attributes and origin of the Malawi 2022-2023 Vc outbreak isolates. Our results demonstrate the predominance of ST69 clone, also known as the seventh cholera pandemic El Tor (7PET) lineage, expressing O1 Ogawa (~ 80%) serotype followed by Inaba (~ 16%) and sporadic non-O1/non-7PET serogroups (~ 4%). Phylogenetic reconstruction revealed that the Malawi outbreak strains correspond to a recent importation from Asia into Africa (sublineage AFR15). These isolates harboured known antimicrobial resistance and virulence elements, notably the ICEGEN/ICEVchHai1/ICEVchind5 SXT/R391-like integrative conjugative elements and a CTXφ prophage with the ctxB7 genotype compared to historical Malawian Vc isolates. These data suggest that the devastating cyclones coupled with the recent importation of 7PET serogroup O1 strains, may explain the magnitude of the 2022-2023 cholera outbreak in Malawi.

Watery Diarrhea Is Not Always Clostridioides difficile: A Case Report of Aeromonas hydrophila Gastroenteritis

Aeromonas species can cause acute gastroenteritis but are much less commonly observed in the hospital setting than other bacteria. Most cases of Aeromonas hydrophila gastroenteritis reported in the literature have occurred in pediatric, elderly, and/or immunocompromised patients. We present a case of subacute watery diarrhea due to A. hydrophila infection in an otherwise healthy 48-year-old female patient with prior abdominal surgeries and recent hospitalization for a catheter-associated urinary tract infection (CAUTI) for which she received antibiotics. The patient presented with 10 days of increasingly frequent non-bloody, watery, foul-smelling diarrhea as well as decreased oral intake, cramping bilateral upper abdominal pain, chills, and malaise. Initial diagnoses considered included Clostridioides difficile in the setting of CAUTI and antibiotic use, small intestinal bacterial overgrowth, dumping syndrome related to bariatric surgery, and malabsorption. A computed tomography scan of her abdomen/pelvis, admission labs, and flexible sigmoidoscopy showed no relevant findings. Stool cultures eventually returned positive for A. hydrophila. The case is an uncommon presentation of Aeromonas infection that could be easily missed while other diagnoses are pursued. Early treatment of Aeromonas infection can be crucial in preventing advanced forms of disease such as septicemia and necrotizing fasciitis.

Draft genomes of Aeromonas caviae from patients with cholera-like illness during the 2022-2023 cholera outbreak in Malawi

Aeromonas caviae is an increasingly recognized etiological agent of acute gastroenteritis. Here, we report five draft genomes of A. caviae isolated from suspected cholera cases during the 2022-2023 cholera outbreak in Malawi.

Aeromonas allosaccharophila Strain AE59-TE2 Is Highly Antagonistic towards Multidrug-Resistant Human Pathogens, What Does Its Genome Tell Us?

Multidrug-resistant bacteria are of critical importance and a problem for human health and food preservation; the discovery of new antimicrobial substances to control their proliferation is part of the solution. This work reports on 57 antagonistic Aeromonas strains, of which 38 strains were antagonistic towards problematic human pathogens. The genome of the most antagonistic strain was sequenced and identified as Aeromonas allosaccharophila. Its genome was fully annotated and mined for genes that might explain that activity. Strain AE59-TE was antagonistic toward clinically relevant gram-negative and gram-positive multidrug-resistant bacteria, including Klebsiella pneumoniae KPC, Escherichia coli ESBL, Salmonella typhimurium, and Staphylococcus aureus MRSA. Strain AE59-TE2 was identified by multilocus sequence analysis. Genome mining identified four genes homologous to the bacteriocin, zoocin A from Streptococcus equi and a gene 98% similar to cvpA linked to colicin V production. A. allosaccharophila strain AE59-TE2 produced antimicrobial activity against a broad range of bacteria, including important gram-negative bacteria, not typically targeted by bacteriocins. Herewere described novel zoocin genes that are promising for industrial applications in the food and health sectors. Interesting and important antagonistic activity is described combined with the first detailed genomic analysis of the species Aeromonas allosaccharophila.