Impact of Ceftazidime-Avibactam Treatment in the Emergence of Novel KPC Variants in the ST307-Klebsiella pneumoniae High-Risk Clone and Consequences for Their Routine Detection

Abstract

Emergence of Klebsiella pneumoniae ( Kp ) isolates carrying novel bla KPC variants conferring ceftazidime-avibactam (CAZ/AVI) resistance is being increasingly reported. We evaluated the accuracy of phenotypic methods commonly used in routine clinical laboratories in the detection of novel KPC enzymes. Additionally, we characterized by WGS the KPC-ST307- Kp isolates recovered in our hospital before and after CAZ/AVI therapy. Rectal colonization or infection by carbapenem-resistant KPC-3- Kp isolates (imipenem MIC 16 mg/L, meropenem MIC 8->16 mg/L) and CAZ/AVI-susceptible (CAZ/AVI MIC 1-2 mg/L) were first detected in three ICU patients admitted between March-2020 and July-2020. KPC- Kp isolates with increased CAZ/AVI MICs (8-32 mg/L) and carbapenem susceptibility (imipenem and meropenem MIC <1 mg/L) were recovered within 6-24 days after CAZ/AVI treatment. WGS confirmed that all KPC- Kp isolates belonged to the ST307 high-risk clone and carried identical antimicrobial resistance genes and virulence factors. The presence of the novel bla KPC-46 , bla KPC-66 and bla KPC-92 genes was confirmed in the Kp isolates with increased CAZ/AVI MICs and restored carbapenem activity. KPC production was confirmed by immunochromatography, the eazyplex®-Superbug-CRE system and the Xpert® Carba-R assay in all KPC- Kp isolates, but not in any isolate using chromogenic agar plates for carbapenemase producers (ChromID-CARBA), the KPC/MBL/OXA-48 Confirm Kit and the β-CARBA test. Nevertheless, all grew in chromogenic agar plates for ESBL producers (ChromID-ESBL). We report the failure of the most common phenotypic methods used for the detection of novel KPC carbapenemases but not of rapid molecular or immunochromatography assays thus highlighting their relevance in microbiology laboratories.

International and regional spread of carbapenem-resistantKlebsiella pneumoniaein Europe

“…In order to monitor the clonal evolution and geographical expansion over time, new tools such as WGS have been implemented. The characterization of carbapenem-resistant isolates is essential for infection control purposes because of their impact on therapeutic decisions in clinics, hence laboratory detection providing high accuracy and fast diagnosis is key for accurate antibiotic delivery (Hernández-García et al, 2022). The entire collection of 683 isolates in this present study (COMBACTE-CARE EURECA) exhibited phenotypic resistance to at least one carbapenem commonly used to treat infections caused by multiple drug-resistant pathogens.…”

“…In addition, it is considered a replacement of other high-risk clones, such as ST258 in countries like Colombia (Ocampo et al, 2015), South Africa (Lowe et al, 2019), and Italy (Bonura et al, 2015). Furthermore, it was also responsible for nosocomial outbreaks harbouring bla KPC variants conferring ceftazidime-avibactam resistance (Hernández-García et al, 2022) and more recently cefiderocol resistance(Castillo-Polo et al, 2023). The presence of several chromosomally and plasmid-encoded factors associated with hypervirulence make ST307 a superior clone that can easily share large plasmids with other Kp and Enterobacterales species such as the Enterobacter cloacae complex (Heiden et al, 2020).…”

Current Positioning against Severe Infections Due to Klebsiella pneumoniae in Hospitalized Adults

“…In patients previously treated with CAZ-AVI, strains may appear to be resistant to this antibiotic that also appear to be sensitive to meropenem in the antibiogram; phenotypic tests may not detect carbapenemases, and if there is no sensitivity to CAZ-AVI the situation may go unnoticed [ 90 , 91 , 92 , 93 ].…”

Antimicrobial resistance in Gram-negative bacilli in Spain: an experts’ view

“…Some strains are resistant to ceftazidime-avibactam due to KPC variants, and they recover susceptibility to meropenem and imipenem, maintaining the effect of the inhibitors vaborbactam and relebactam [22,[24][25][26]. Knowing this information can help in selecting antibiotics when the susceptibility of others is compromised.…”

“…Another aspect that should be monitored is the emergence of HRC with KPC variants, such as ST307, that confer resistance to ceftazidime-avibactam [22,23] and that, at least partially, recover the susceptibility to carbapenems such as meropenem-vaborbactam and imipenem-relebactam. This susceptibility recovery is due to collateral susceptibility to meropenem or imipenem and due to the maintenance of inhibitory activity of vaborbactam and relebactam over these KPC variants [22][23][24][25][26]. Cases of KPC variants with resistance to new antibiotics such as cefiderocol have also been described [27].…”