Multidrug Resistant Klebsiella pneumoniae ST101 Clone Survival Chain From Inpatients to Hospital Effluent After Chlorine Treatment

In this paper we describe the transmission of a multi-drug resistant Klebsiella pneumoniae ST101 clone from hospital to wastewater and its persistence after chlorine treatment. Water samples from influents and effluents of the sewage tank of an infectious diseases hospital and clinical strains collected from the intra-hospital infections, during a period of 10 days prior to wastewater sampling were analyzed. Antibiotic resistant K. pneumoniae strains from wastewaters were recovered on selective media. Based on antibiotic susceptibility profiles and PCR analyses of antibiotic resistance (AR) genetic background, as well as whole-genome sequencing (Illumina MiSeq) and subsequent bioinformatic analyses, 11 ST101 K. pneumoniae strains isolated from hospital wastewater influent, wastewater effluent and clinical sector were identified as clonally related. The SNP and core genome analyses pointed out that five strains were found to be closely related (with ≤18 SNPs and identical cgMLST profile). The strains belonging to this clone harbored multiple acquired AR genes [bla_CTX–M–15, bla_OXA–48, bla_OXA–1, bla_SHV–106, bla_TEM–150, aac(3)-IIa, aac(6′)-Ib-cr, oqxA10, oqxB17, fosA, catB3, dfrA14, tet(D)] and chromosomal mutations involved in AR (ΔmgrB, ΔompK35, amino acid substitutions in GyrA Ser83Tyr, Asp87Asn, ParC Ser80Tyr). Twenty-nine virulence genes involved in iron acquisition, biofilm and pili formation, adherence, and the type six secretion system – T6SS-III were identified. Our study proves the transmission of MDR K. pneumoniae from hospital to the hospital effluent and its persistence after the chlorine treatment, raising the risk of surface water contamination and further dissemination to different components of the trophic chain, including humans.

Molecular epidemiology and the clinical impact of carbapenemase-producing Enterobacterales isolates among adult patients: aspects from a Romanian non-teaching hospital

Introduction: A dramatic increase of infections induced by carbapenemase-producing Enterobacterales (CPE) has been registered worldwide. The aim of this study was to evaluate the molecular epidemiology and the clinical impact of CPE strains isolated from adult inpatients.

Material and methods: A one-year, single-center, retrospective observational study including 34 consecutive patients with 37 non-duplicate CPE strains recovered from clinical specimens was accomplished. The Vitek 2 Compact, M.I.C.Evaluator strips, the modified carbapenem inactivation method (mCIM), and the combination disks test (KPC, MBL, OXA-48 Confirm kit, Rosco Diagnostica) were applied as phenotypic tests. A multiplex polymerase chain reaction (PCR) assay was used for detection of blaKPC, blaNDM, and blaOXA-48-like genes. The clonality was assessed with pulsed-field gel electrophoresis (PFGE).

Results: Klebsiella pneumoniae (n=25) was the most frequent CPE encountered. The carbapenemase types were NDM (n=13), KPC (n=12), and OXA-48-like (n=12). Two distinct clonal clusters were identified among the 12 KPC positive strains. All CPE isolates exhibited non-susceptibility to carbapenems, cephalosporins, ciprofloxacin. Respiratory tract infections (n=16) and hospitalization in the intensive care unit (ICU) (n=14) were dominant. The most common comorbidity was congestive heart failure (n=11). Monotherapy was the main strategy adopted (n=15). Death occurred in 18 patients.

Conclusions: Our analysis underscores the scarcity of antibiotic solutions and high mortality. Monotherapy for urinary tract infections (UTIs) is beneficial. Inter- or intrahospital dissemination of successful epidemic clones is proved. The adequate CPE infections control programs and antimicrobial policies are essential..

Phenotypic and molecular identification of carbapenemase-producing Enterobacteriaceae - challenges in diagnosis and treatment

Introduction: Infections due to carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CPCRE) are an emerging global public health threat. The purpose of this study was to investigate phenotypic and genotypic features of CP-CRE strains isolated from hospitalized patients. Material and methods: Between 1st of January - 1st of July 2017, in the Department of Microbiology, “Dr. Constantin Opriş” County Emergency Hospital Baia Mare, Romania, 1110 strains of Enterobacteriaceae were isolated from bronchial secretions, urine, wounds and blood cultures. Bacterial identification and antimicrobial susceptibility tests were performed by conventional methods, Vitek 2 Compact and M.I.C.E. strips. We analysed all Enterobacteriaceae strains non-susceptible to carbapenems according to CLSI 2017 criteria. The modified Hodge test (MHT), the modified carbapenem inactivation method (mCIM) and the combination disks test (KPC, MBL, OXA-48 Confirm kit, Rosco Diagnostica) were used for phenotypic confirmation, whereas a multiplex PCR assay for genes blaKPC, blaNDM and blaOXA-48 was used for genetic confirmation. Results: 19 non-duplicate strains isolated from 16 patients were phenotypically identified as CP-CRE: Klebsiella pneumoniae (n=14), Escherichia coli (n=2), Providencia stuartii (n=2) and Serratia marcescens (n=1). Most strains were isolated from bronchial secretions (n=9). The carbapenem-hydrolizing enzymes were identified by the combination disks test as: KPC (n=9), OXA-48-like (n=5) and MBL (n=5). Molecular confirmation was performed in 18 phenotypically positive isolates with 100% concordant results with mCIM and combination disks test. Discrepant results were noticed with the MHT in case of 4 NDM-producers confirmed by PCR. All CP-CRE strains were resistant to all tested cephems. Three out of 9 K. pneumoniae strains tested against colistin were found resistant. Conclusions: The most common carbapenemase detected was KPC. Therapeutic options were limited in all positive cases. Rapid and reliable detection of CP-CRE is critical for preventing the spread of these pathogens