Comparative analysis of a rapid diagnostic test and scoring tools for ESBL detection in Enterobacterales bloodstream infections for optimizing antimicrobial therapy.

IMPORTANCE: Our study addresses a significant issue in the medical and scientific community-the delayed administration of appropriate antimicrobial treatments due to the time-consuming process of phenotypic susceptibility data collection in gram-negative bloodstream infections. Our research indicates that a multiplex PCR rapid diagnostic test (RDT) significantly outperformed two clinical scoring tools in predicting ceftriaxone susceptibility. Multiplex PCR also led to reduced instances of undertreatment with ceftriaxone and minimized overtreatment with carbapenems. Furthermore, multiplex PCR demonstrated high sensitivity and specificity in predicting ceftriaxone susceptibility. The results of our study underscore the potential RDTs to reduce the time to appropriate antimicrobial therapy, leading to improved patient outcomes and reduced healthcare costs.

Leptotrichia bacteremia in patients receiving high-dose chemotherapy.

Leptotrichia spp. are anaerobic, pencil-shaped, Gram-negative rods that are part of the normal oral and intestinal human flora. Although not typically considered pathogenic, invasive Leptotrichia infections have been reported in immunosuppressed patients. A perceived rise in the identification of Leptotrichia spp. at our institution prompted a retrospective evaluation of these infections. Laboratory and clinical records were reviewed to identify Leptotrichia culture-positive patients. Over a 5-year period, 68 Leptotrichia-positive specimens were identified. Of these, 21% (14/68) were identified in original samples submitted from 13 different patients at our institution, and the remainder (79% [54/68]) were unknown isolates referred from outside hospitals for molecular identification. All in-house Leptotrichia were identified from blood cultures. Only 64% (9/14) of these grew on solid media, and 5 were a part of polymicrobial bacteremias containing other enteric pathogens. All local patients were receiving chemotherapy and a majority received hematopoietic stem cell transplant (HSCT) (11/13). All had neutropenic fever with symptoms of mucositis and/or enteritis. Most of the HSCT patients (73% [8/11]) were autologous recipients hospitalized after recent high-dose chemotherapy for multiple myeloma. L. hongkongensis, a novel species, was found in the majority of myeloma cases (63% [5/8]). In conclusion, we suggest that Leptotrichia spp. may be an underappreciated cause of bacteremia, particularly in multiple myeloma patients receiving cytotoxic chemotherapy for autologous HSCT. In our cohort, these infections were associated with neutropenic fever from an enteric source, and most isolates remained sensitive to standard antibiotics.

Corynebacterium falsenii bacteremia occurring in an infant on vancomycin therapy.

Corynebacterium falsenii was described in 1998 as a new Corynebacterium species. We give the first detailed description of a clinically significant Corynebacterium falsenii bacteremia occurring in an infant while on vancomycin therapy.

Testing intra-hemocelic injection of antimicrobials against Encephalitozoon sp. (Microsporidia) in an insect host.

Encephalitozoon spp. are the primary microsporidial pathogens of humans and domesticated animals. In this experiment, we test the efficacy of four commercial antimicrobials against an Encephalitozoon sp. in an insect host by intra-hemocelic injection. All four antimicrobials, viz., thiabendazole, quinine, albendazole, and fumagillin, significantly reduced but did not eliminate microsporidia spore counts in the grasshopper host. Among these four drugs, thiabendazole was most effective in reducing the microsporidia spore level up to 90%, followed by quinine (70%), albendazole (62%), and fumagillin (59%). No control or quinine-treated animals died, whereas 45% of albendazole animals died. Despite the high mortality induced by albendazole, this drug significantly reduced spore counts, a result not seen in previous per os trials. Among the treatment groups, grasshoppers injected with thiabendazole lost a significant mass. Our study suggests that quinine and related alkaloids should be further examined for antimicrosporidial activity.