Comparison of Four Carbapenemase Detection Methods for bla _KPC-2 Variants

Abstract

Rural communities often rely on groundwater for potable water supply. In this study, untreated groundwater samples from 28 shallow groundwater wells in Finland (<10 m deep and mostly supplying untreated groundwater to <200 users in rural areas) were assessed for physicochemical water quality, stable water isotopes, microbial water quality indicators, host-specific microbial source tracking (MST) markers, and bacterial community composition, activity, and diversity (using amplicon sequencing of the 16S rRNA gene and 16S rRNA). Indications of surface water intrusion were identified in five wells, and these indications were found to be negatively correlated, overall, with bacterial alpha diversity (based on amplicon sequencing of the 16S rRNA gene). High levels of turbidity, heterotrophs, and iron compromised water quality in two wells, with values up to 2.98 nephelometric turbidity units (NTU), 16,000 CFU/ml, and 2,300 μg/liter, respectively. Coliform bacteria and general fecal indicator <italic>Bacteroidales</italic> bacteria (GenBac3) were detected in 14 and 10 wells, respectively (albeit mostly at low levels), and correlations were identified between microbial, physicochemical, and environmental parameters, which may indicate impacts from nearby land use (e.g., agriculture, surface water, road salt used for deicing). Our results show that although water quality was generally adequate in most of the studied wells, the continued safe use of these wells should not be taken for granted.</p> <p><bold>IMPORTANCE</bold> Standard physicochemical water quality analyses and microbial indicator analyses leave much of the (largely uncultured) complexity of groundwater microbial communities unexplored. This study combined these standard methods with additional analyses of stable water isotopes, bacterial community data, and environmental data about the surrounding areas to investigate the associations between physicochemical and microbial properties of 28 shallow groundwater wells in Finland. We detected impaired groundwater quality in some wells, identified potential land use impacts, and revealed indications of surface water intrusion which were negatively correlated with bacterial alpha diversity. The potential influence of surface water intrusion on groundwater wells and their bacterial communities is of particular interest and warrants further investigation because surface water intrusion has previously been linked to groundwater contamination, which is the primary cause of waterborne outbreaks in the Nordic region and one of the major causes in the United States and Canada. IMPORTANCE Standard physicochemical water quality analyses and microbial indicator analyses leave much of the (largely uncultured) complexity of groundwater microbial communities unexplored. This study combined these standard methods with additional analyses of stable water isotopes, bacterial community data, and environmental data about the surrounding areas to investigate the associations between physicochemical and microbial properties of 28 shallow groundwater wells in Finland. We detected impaired groundwater quality in some wells, identified potential land use impacts, and revealed indications of surface water intrusion which were negatively correlated with bacterial alpha diversity. The potential influence of surface water intrusion on groundwater wells and their bacterial communities is of particular interest and warrants further investigation because surface water intrusion has previously been linked to groundwater contamination, which is the primary cause of waterborne outbreaks in the Nordic region and one of the major causes in the United States and Canada.

Comparison of Lateral Flow Immunochromatography and Phenotypic Assays to PCR for the Detection of Carbapenemase-Producing Gram-Negative Bacteria, a Multicenter Experience in Mexico

“…In Mexico, Garza Garcia et al reported the distribution of carbapenem-encoding genes in Enterobacterales: the most frequently detected were bla NDM-1 (81.5%) followed by bla OXA-48 [17]. We found carbapenem-encoding genes such as bla NDM-1 , bla NDM-5 , bla KPC-2 , bla KPC3 , bla OXA-181 , bla OXA-232 , and bla VIM-2 , but as we know bla KPC-82 and bla VIM-67 have not been previously described in Enterobacterales with NG-Test CARBA 5 ® [31][32][33][34][35].…”

Multiple Novel Ceftazidime-Avibactam-Resistant Variants of bla KPC-2 -Positive Klebsiella pneumoniae in Two Patients

“…Problems arose in the clinical detection of these novel KPC variants owing to their inconspicuous resistant characteristic of carbapenems and lack of routine ceftazidime-avibactam susceptibility testing. Routine detection methods of carbapenemase-like modified carbapenem inactivation method (mCIM)/EDTA-modified CIM (eCIM) recommended by CLSI and 3-aminophenylboronic acid (APB) or EDTA synergy test show negative results for these isolates, whereas the detection results of GeneXpert Carba-R are all positive, suggesting an indeterminate KPC allele, which is often speculated as KPC-2 type in China ( 39 – 41 ). All test results might lead to incorrect prediction of ceftazidime-avibactam susceptibility, resulting in incorrect clinical usage.…”

MALDI-TOF MS-Based Approaches for Direct Identification of Gram-Negative Bacteria and BlaKPC-Carrying Plasmid Detection from Blood Cultures: A Three-Year Single-Centre Study and Proposal of a Diagnostic Algorithm

“…Nine of these isolates were previously investigated by DNA sequencing revealing mutations in bla KPC associated with ceftazidime/avibactam resistance (substitution D179Y, n = 8; duplication EL167–168, n = 1) [ 23 , 24 , 25 ]. KPC variants conferring ceftazidime/avibactam resistance are an increasing concern as characterized to be undetectable by the main phenotypic carbapenemase detection methods including immunochromatographic assays [ 23 , 24 , 26 ]. Since phenotypic assays represent the most used and cost-saving method to identify carbapenemase producers in clinical microbiology laboratories, failure to recognize these mutated-KPC-producing strains could facilitate their spread in hospital setting [ 22 , 27 ].…”