Faropenem disks for screening of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae

A systematic scoping review of faropenem and other oral penems: treatment of Enterobacterales infections, development of resistance and cross-resistance to carbapenems

Background

Antimicrobial resistance is an urgent global healthcare concern. Beyond carbapenems as broad-spectrum, often 'last resort' antibiotics, oral penem antibiotics currently are approved only in Japan and India, used for the treatment of indications including urinary tract infections (UTIs). Exploring oral penem use to better understand the impact of antibiotic resistance on public health would help inform the management of infectious diseases, including UTIs.

Scoping Review Methodology

This scoping review investigated the impact of faropenem and other oral penems on Enterobacterales infection treatment and evaluated evidence for faropenem resistance and cross-resistance to carbapenems. PubMed, Embase, J-STAGE and CiNii were searched for relevant English- or Japanese-language articles published between 1 January 1996 and 6 August 2021.

Key Findings

From 705 unique publications, 29 eligible articles were included (16 in vitro studies; 10 clinical trials; 2 in vitro and in vivo studies; and 1 retrospective medical chart review). Limited evidence described faropenem to treat infectious disease; only four randomized clinical trials were identified. Faropenem dosing regimens varied broadly within and between indications. One study indicated potential dependence of penem efficacy on underlying antibiotic resistance mechanisms, while several studies reported UTI persistence or recurrence after faropenem treatment. In vitro MIC data suggested some potential bacterial resistance to faropenem, while limited clinical data showed resistance emergence after faropenem treatment. Preliminary in vitro evidence suggested faropenem resistance might foster cross-resistance to carbapenems. Overall, very limited clinical evidence describes faropenem for treating infectious diseases. Preclinical and clinical research investment and dedicated community surveillance monitoring is crucial for understanding faropenem treatment patterns, resistance and potential cross-resistance to carbapenems.

Evaluation of the VITEK2 AST-XN17 card for the detection of carbapenemase-producing Enterobacterales in isolates primarily producing metallo β-lactamase

Carbapenemase-producing Enterobacterales (CPE) are not always resistant to carbapenem antimicrobial susceptibility testing (AST) and can be difficult to detect. With the newly created VITEK2 AST-XN17 card, the types of antibiotics measured in AST can be increased. In this study, we evaluated the detectability of CPE using the results of AST with multiple antimicrobial agents with additional measurements of the AST-XN17 card. In addition, we evaluated the CPE detectability of comments on CPE using the VITEK2 Advance Expert System (AES). In total, 169 Enterobacterales samples, including 76 non-CPE and 93 CPE, collected from multiple medical institutions in the Kinki region of Japan, were used in this investigation. AST with VITEK2 was performed by adding the AST-XN17 card in addition to the AST-N268 or AST-N404 card. Measurement results were identified using cutoff values, primarily Clinical and Laboratory Standards Institute breakpoints, and the CPE detection capability of each antibiotic was evaluated in several terms, including sensitivity and specificity. The drugs highly sensitive to CPE detection were faropenem (FRPM) > 2 µg/mL at 100% and meropenem > 0.25 µg/mL at 98.9%; the highest specificity to CPE detection was for avibactam/ceftazidime (AVI/CAZ) > 8 µg/mL at 100%. The sensitivity and specificity of each card in the AES output were 86.2% and 94.7% for AST-N404 and AST-XN17 and 91.5% and 90.8% for AST-N268 and AST-XN17, respectively. AST using the VITEK2 AST-XN17 card is a useful test method of screening for CPE.

Comparison of Phenotypic Tests and an Immunochromatographic Assay and Development of a New Algorithm for Detection of OXA-48-like Carbapenemases

OXA-48 is the most prevalent carbapenemase in Enterobacteriaceae in Europe and the Middle East, but it is frequently missed because many isolates display low MICs for carbapenems. Furthermore, in contrast to metallo-β-lactamases or Klebsiella pneumoniae carbapenemases (KPC), no specific inhibitor is available for the phenotypic detection of OXA-48. Molecular detection of bla_OXA-48 is the "gold standard" but is not available in many laboratories. A few phenotypic assays have been described but have not been independently evaluated. The aim of this study was the systematic comparison of phenotypic tests and an immunochromatographic assay (ICT) for the detection of OXA-48/OXA-48-like carbapenemases and the development of an algorithm for reliable phenotypic detection of OXA-48. Four phenotypic tests (temocillin disk test, faropenem disk test, OXA-48 disk test, and high-inoculum [HI] OXA-48 disk test) and a new ICT (OXA-48 K-SeT) were compared by using a set of 166 Enterobacteriaceae isolates, including isolates producing OXA-48/OXA-48-like carbapenemases (n = 84) or Ambler class A and B carbapenemases (n = 41) and carbapenemase-negative isolates (n = 41). The sensitivity and specificity for the different assays were 100% and 43.9% for temocillin, 57.1% and 98.8% for faropenem, 53.6% and 100% for the OXA-48 disk test, 98.8% and 97.6% for the HI OXA-48 disk test, and 100% and 100% for the ICT, respectively. The ICT displayed the highest sensitivity and specificity and was the most rapid assay, but it is more costly than phenotypic assays. Based on these results, a new algorithm incorporating temocillin, faropenem, and ICT which allows cost-effective detection of OXA-48 with 100% sensitivity and specificity was developed.

Intestinal Carriage of Carbapenemase-Producing Organisms: Current Status of Surveillance Methods

Carbapenemases have become a significant mechanism for broad-spectrum β-lactam resistance in Enterobacteriaceae and other Gram-negative bacteria such as Pseudomonas and Acinetobacter spp. Intestinal carriage of carbapenemase-producing organisms (CPOs) is an important source of transmission. Isolation of carriers is one strategy that can be used to limit the spread of these bacteria. In this review, we critically examine the clinical performance, advantages, and disadvantages of methods available for the detection of intestinal carriage of CPOs. Culture-based methods (Centers for Disease Control and Prevention [CDC] protocols, chromogenic media, specialized agars, and double-disk synergy tests) for detecting carriage of CPOs are convenient due to their ready availability and low cost, but their limited sensitivity and long turnaround time may not always be optimal for infection control practices. Contemporary nucleic acid amplification techniques (NAATs) such as real-time PCR, hybridization assays, loop-mediated isothermal amplification (LAMP), or a combined culture and NAAT approach may provide fast results and/or added sensitivity and specificity compared with culture-based methods. Infection control practitioners and clinical microbiologists should be aware of the strengths and limitations of available methods to determine the most suitable approach for their medical facility to fit their infection control needs.