Diagnostic microbiology and infectious disease最新文献

Blood culture (BC) remains the reference diagnostic tool for bloodstream infections but is hampered by long turn-around time (TAT). This study evaluated the Vitek® Reveal™ (VR) system for rapid antimicrobial susceptibility testing (AST) with 72 cases of monomicrobial BCs (55 Enterobacterales, 12 Pseudomonas aeruginosa and 5 Acinetobacter baumannii), including isolates producing carbapenemases and/or extended-spectrum β-lactamases. VR returned AST results with a mean TAT of 5.4 h. Compared to a conventional workflow based on broth microdilution, VR exhibited essential agreement (EA) and category agreement (CA) >90 % in most cases, except with meropenem for Enterobacterales (CA, 85.5 %), piperacillin/tazobactam for P. aeruginosa (EA, 83.3 %), and trimethoprim/sulfamethoxazole for A. baumannii (CA and EA, 80 %). Bias exhibited an underestimation trend with ceftazidime/avibactam (−78.9 %) and ceftazidime (−50 %) for Enterobacterales and P. aeruginosa, respectively. Overall, VR appears an interesting tool to decrease TAT of the BC workflow, although further evaluation with some antibiotic-pathogen combinations would be warranted.

We describe a case of a 33-year-old male presented with fever, myalgia, nausea, and asthenia for six days. The patient lived in a rural area. Initial hypotheses included arbovirus infection, viral hepatitis, and Lyme disease. Reverse transcriptase polymerase chain reaction (RT-PCR) tests for Dengue, Zika, and Chikungunya resulted negative. We were able to recover complete S, L, and M segments of virus in the Orthohantavirus genome.

Tauroursodeoxycholic acid (TUDCA) is a naturally occurring hydrophilic bile acid that alleviates endoplasmic reticulum (ER) stress and inhibits apoptosis, thereby protecting cells. Previous studies have shown that enterovirus 71 (EV71) infection modulates ER stress and induces autophagy to assist viral replication. This study observed the effects of TUDCA pretreatment on HeLa and Vero cells infected with EV71, finding that TUDCA inhibits EV71 replication in TUDCA pretreated HeLa and Vero cells in a dose-dependent manner. We found that TUDCA pretreatment inhibited EV71 replication by regulating three branches of UPR, that is up-regulated ATF6, down-regulated both PERK and IRE1. The results also indicated that autophagy which is downstream of UPR, was inhibited either. The results indicate that TUDCA inhibits EV71 replication by regulating UPR sensor proteins and autophagy following ER stress.

We present the case of a 3-month-old immunocompromised infant who developed a vascular catheter-related bloodstream infection caused by Pantoea septica. Susceptibility testing results for this isolate and 10 additional clinical strains are provided to help define the susceptibility profile of this infrequently recovered organism.

Burkholderia pseudomallei is a pathogen expanding in geographic range. We performed a retrospective study analyzing the clinical, microbiologic features of culture-proven melioidosis, and predictors of mortality based on data from a Singapore tertiary hospital between 2006- 2016. We found ICU admission, bacteremia, and mechanical ventilation to be associated with mortality.

Purpose

The identification of anaerobes, Mycobacterium and Nocardia species, and moulds by MALDI-TOF-MS remains a challenge. This study aimed to evaluate the performance of MALDI-TOF in the identification of these organisms.

Methods

A total of 382 strains, comprising 128 (33.5 %) anaerobes, 126(33.0 %) mycobacterial, 113(29.6 %), mycelial fungi, and 15(3.9 %) Nocardia species were evaluated by VITEK MS Version 3.0. The results were compared with the identification of the isolates by DNA sequence analysis. The DNA sequences used for analysis were the 16S rRNA for anaerobic bacteria, hsp65 gene for mycobacteria, whereas both 16S rRNA and hsp65 gene for Nocardia species, and internal transcribed spacer (ITS) and 28S rRNA gene's D1/D2 regions of fungi.

Results

The VITEK-MS accurately identified 78.3 % (299/382) of the strains at the species, and 9.4 % (36/382) at the genus level. Misidentifications were observed in 3.9 % (15/382) isolates. Of isolates tested, 8.4 % (32/382) were not identified by the system, and 7.06 % (27/382) were not included in the IVD database.

Conclusion

An upgraded VITEK MS V3.0 database provides reasonably accurate and rapid identification of clinically relevant anaerobes, mycobacteria, Nocardia species, and moulds to the species level.

We aimed to present a case of two mesocolonic hydatid cysts that mimicked the presentation of peritoneal pseudomyxoma. Hydatidosis is a zoonotic parasitic infection caused by the cestode Echinococcus spp., whose larval stage affects various organs. The present case describes a 40-year-old male patient who presented with severe lower abdominal pain and was diagnosed with acute appendicitis. The patient underwent an appendectomy and was later referred to an oncology surgery clinic because of imaging findings suggestive of peritoneal pseudomyxoma or carcinomatosis. A video-assisted laparoscopic procedure revealed two cysts and microscopic findings confirmed hydatid cysts. The patient was from a hydatidosis-endemic region of southern Brazil. This case highlights the diagnostic challenges and the need for a multidisciplinary approach and careful histopathological analysis in patients with complex abdominal conditions. This also demonstrates the importance of disseminating knowledge about this condition and its management.

Purpose

Phenotypic methods have been proposed for the detection of carbapenemase production. These tests can have slower turnaround times. With the sensitivity-based algorithm described by Gill et al. will be possible to detect the carbapenemase.

Methods

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates from three hospitals between January 2017 and December 2021 were included. The modified carbapenemase-inactivation-method(mCIM) and two algorithms were used, defined as "primary algorithm, i.e. ceftazidime and cefepime non-susceptible in addition to imipenem or meropenem resistance" and "secondary algorithm, i.e. ceftolozane/tazobactam non-susceptible in addition to imipenem or meropenem resistance". PCR testing was performed on all isolates.

Results

256 CRPA isolates were included in the study. When the primary or secondary algorithm criteria were applied, there were 173 isolates that met one or both of them. Of these, 29 were CIM-positive isolates.

Conclusion

In our study, the use of the algorithm reduced the need for CIM testing by 32 %.