Characterization of ESBL-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Clinical Samples in a Northern Portuguese Hospital: Predominance of CTX-M-15 and High Genetic Diversity

Pons M. Antimicrobial resistance and associated risk factors in Escherichia coli isolated from Peruvian dogs: A focus on extended-spectrum β-lactamases and colistin

Background and Aim

Established antimicrobial resistance (AMR) surveillance in companion animals is lacking, particularly in low-middle-income countries. The aim of this study was to analyze AMR and its risk factors in Escherichia coli isolated from dogs at two veterinary centers in Lima (Peru).

Materials and Methods

Ninety dogs were included in the study. Antimicrobial susceptibility was established by disk diffusion, whereas microdilution was used to determine colistin susceptibility. Mechanisms related to extended-spectrum β-lactamases (ESBL) and colistin resistance were determined by polymerase chain reaction. Clonal relationships of colistin-resistant isolates were assessed by XbaI-pulsed-field gel electrophoresis.

Results

Thirty-five E. coli strains were isolated. High levels of resistance to ampicillin (57.1%), nalidixic acid (54.3%), tetracycline (48.6%), and azithromycin (25.7%) were detected. Cephalosporin resistance levels were ≥20% and those for colistin were 14.3%. Twelve (34.2%) isolates were ESBL producers; of these, six blaCTX-M-55 (50.0%), 2 (16.6%) blaCTX-M-15, and 2 (16.6%) blaCTX-M-8-like genes were found. The five colistin-resistant isolates were clonally unrelated, with four of them presenting amino acid codon substitutions in the mgrB gene (V8A) or mutations in the mgrB promoter (a12g, g98t, and c89t). Furthermore, dog age, <6 years (p = 0.027) and raw diet (p = 0.054) were associated with resistance to a greater number of antibiotic families.

Conclusion

Despite small number of samples included, the study found that dogs studied were carriers of multidrug-resistant E. coli, including last-resort antimicrobials, representing a public health problem due to close contact between dogs and humans. This issue suggests the need for larger studies addressed to design strategies to prevent the spread of resistant micro-organisms in small animal clinics and domestic settings.

Emergence and dissemination of epidemic-causing OXA-244 carbapenemase-producing Escherichia coli ST38 through hospital sewage in Norway, 2020-2022

BACKGROUND

Population-based sewage surveillance has emerged as a promising approach for studying the prevalence of antibiotic resistance in pathogens.

AIM

To determine the temporal prevalence of cefotaxime-resistant Escherichia coli in sewage from five sewage treatment plants located in Bergen city, to determine whether ESBL- and carbapenemase-producing E. coli are consistently disseminated in the receiving environment through sewage.

METHOD

A total of 569 cefotaxime-resistant E. coli were isolated over a period of 19 months (August 2020 to February 2022) using ECC CHROMagar™ plates from 82 samples, antibiotic sensitivity profiles were determined, using Sensititre™ plates. The draft genome sequences were determined, using Illumina MiSeq-based sequencing. Complete genome sequences were determined, using Oxford Nanopore-based sequencing.

FINDINGS

All 569 strains obtained from influent (N=461) and effluent (N=108) were multi-drug resistant. Most of the sequenced strains (52 of 61) carried blaCTX-M-15 (38.5%) and blaCTX-M-27 (34.6%). The most prevalent sequence types (STs) for ESBL-carrying strains were ST131 (32.8%) and ST38 (21.3%). All CTX-M-27-carrying ST131 strains belonged to clade A or C1, while CTX-M-15-harbouring strains were present in all the clades. Five OXA-244-producing ST38 strains, genetically similar to epidemic-causing strains from Western Norway, France and the Netherlands, were isolated only from raw and treated sewage of the treatment plant receiving hospital sewage.

CONCLUSION

This is the first study showing persistent dissemination of OXA-244-producing ST38 clones through sewage in Norway, demonstrating that hospital sewage is the likely source of OXA-244-producing ST38 clones reaching the receiving environment.

Phenotypic and Genotypic Characterization of Extended Spectrum Beta-Lactamase-Producing Clinical Isolates of Escherichia coli and Klebsiella pneumoniae in Two Kenyan Facilities: A National Referral and a Level Five Hospital

Background

The emergence of antimicrobial resistance (AMR) and multidrug resistance (MDR) among Escherichia coli and Klebsiella pneumoniae, especially through the production of extended spectrum β-lactamases (ESBLs), limits therapeutic options and poses a significant public health threat.

Objective

The aim of this study was to assess the phenotypic and genetic determinants of antimicrobial resistance of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates from patient samples in two Kenyan Hospitals.

Methods

We collected 138 E. coli and 127 K. pneumoniae isolates from various clinical specimens at the two health facilities from January 2020 to February 2021. The isolates' ESBL production and antibiotic susceptibility were phenotypically confirmed using a standard procedure. Molecular analysis was done through conventional polymerase chain reaction (PCR) with appropriate primers for gadA, rpoB, blaTEM, blaSHV, blaOXA, blaCTX-M-group-1, blaCTX-M-group-2, blaCTX-M-group-9, and blaCTX-M-group-8/25 genes, sequencing and BLASTn analysis.

Results

Most E. coli (82.6%) and K. pneumoniae (92.9%) isolates were ESBL producers, with the highest resistance was against ceftriaxone (69.6% among E. coli and 91.3% among K. pneumoniae) and amoxicillin/clavulanic acid (70.9% among K. pneumoniae). The frequency of MDR was 39.9% among E. coli and 13.4% among K. pneumoniae isolates. The commonest MDR phenotypes among the E. coli isolates were CRO-FEP-AZM-LVX and CRO-AZM-LVX, while the FOX-CRO-AMC-MI-TGC-FM, FOX-CRO-FEP-AMC-TZP-AZM-LVX-MI and CRO-AMC-TZP-AZM-MI were the most frequent among K. pneumoniae isolates. Notably, the FOX-CRO-FEP-AMC-TZP-AZM-LVX-MI phenotype was observed in ESBL-positive and ESBL-negative K. pneumoniae isolates. The most frequent ESBL genes were blaTEM (42%), blaSHV (40.6%), and blaOXA (36.2%) among E. coli, and blaTEM (89%), blaSHV (82.7%), blaOXA (76.4%), and blaCTX-M-group-1 (72.5%) were most frequent ESBL genes among K. pneumoniae isolates. The blaSHV and blaOXA and blaTEM genotypes were predominantly associated with FOX-CRO-FEP-MEM and CRO-FEP multidrug resistance (MDR) and CRO antimicrobial resistance (AMR) phenotypes, among E. coli isolates from Embu Level V (16.7%) and Kenyatta National Hospital (7.0%), respectively.

Conclusions

The high proportion of ESBL-producing E. coli and K. pneumoniae isolates increases the utilization of last-resort antibiotics, jeopardizing antimicrobial chemotherapy. Furthermore, the antimicrobial resistance patterns exhibited towards extended-spectrum cephalosporins, beta-lactam/beta-lactamase inhibitor combinations, fluoroquinolones, and macrolides show the risk of co-resistance associated with ESBL-producing isolates responsible for MDR. Hence, there is a need for regular surveillance and implementation of infection prevention and control strategies and antimicrobial stewardship programs.

Occurrence of extended-spectrum β-lactamases-producing Escherichia coli isolates over gradient pollution in an urban tropical estuary

Bacterial resistance to antimicrobials is a global public health problem that surpasses the human context and can be increased by pollution. However, the lack of systematic monitoring of resistance in some aquatic matrices, such as tropical estuaries, makes it unknown whether its occurrence is associated with anthropogenic pollution in these environments. Therefore, we investigated the occurrence of extended-spectrum beta-lactamases (ESBLs) producing Escherichia coli as a resistance indicator for 12 consecutive months at three representative points of a pollution gradient in Guanabara Bay (GB), Brazil. Sixty-six E. coli strains were selected from 72 samples of GB waters in the presence of ceftriaxone (8 μg mL-1 ) and identified by MALDI-TOF MS. Of the 66, 55 (83.3%) strains were ESBL producers. They carried beta-lactamase/ESBL genes, with the predominance of blaCTX-M (54, 98.2%), especially the blaCTX-M-1,2 allele (49.1%). These strains were detected frequently (81.8%) from the point with the highest pollution levels. Furthermore, the marker for Class 1 integron, intI1 gene, was detected in 54.5% of ESBL producers. These data suggest an association between antimicrobial-resistant E. coli and sewage pollution in aquatic environments raising concerns about the possible risks of human exposure to these waters and fish consumption.

The Silent Threat: Antimicrobial-Resistant Pathogens in Food-Producing Animals and Their Impact on Public Health

The emergence of antimicrobial resistance (AMR) is a global health problem without geographic boundaries. This increases the risk of complications and, thus, makes it harder to treat infections, which can result in higher healthcare costs and a greater number of deaths. Antimicrobials are often used to treat infections from pathogens in food-producing animals, making them a potential source of AMR. Overuse and misuse of these drugs in animal agriculture can lead to the development of AMR bacteria, which can then be transmitted to humans through contaminated food or direct contact. It is therefore essential to take multifaceted, comprehensive, and integrated measures, following the One Health approach. To address this issue, many countries have implemented regulations to limit antimicrobial use. To our knowledge, there are previous studies based on AMR in food-producing animals; however, this paper adds novelty related to the AMR pathogens in livestock, as we include the recent publications of this field worldwide. In this work, we aim to describe the most critical and high-risk AMR pathogens among food-producing animals, as a worldwide health problem. We also focus on the dissemination of AMR genes in livestock, as well as its consequences in animals and humans, and future strategies to tackle this threat.

β-Lactamase Genes without Limits

β-Lactams are among the most prescribed antibiotics worldwide, mainly due to their weak toxicity and good efficacy [...].

High prevalence of extensively drug resistant and extended spectrum beta lactamases (ESBLs) producing uropathogenic Escherichia coli isolated from Faisalabad, Pakistan

Urinary tract infections (UTIs) are predominantly caused by uropathogenic Escherichia coli (E. coli). There is rapid increase in antimicrobial resistance in UTIs, also declared as a serious health threat by World Health Organization (WHO). Present study was designed to investigate the antimicrobial resistance status with specific focus on ESBLs and carbapenemases in local uropathogenic E. coli (UPEC) isolates. E. coli isolates were characterized from patients of all ages visiting diagnostic laboratories for urine examination. Demographic data was also recorded for each patient. Antibiograms were developed to observe antibiotic resistance in UPEC using Kirby Bauer disc diffusion technique. Double Disc Synergy test (DDST) was used for phenotypic ESBL test. ESBLs and carbapenemases genes were detected in UPEC using PCR. The PCR results were confirmed by sequencing. The UPEC isolates under study exhibited 78%, 77%, 74%, 72% and 55% resistance against cefotaxime, amoxicillin, erythromycin, ceftriaxone and cefixime, respectively. Resistance against colistin and meropenem was observed in 64% and 34% isolates, respectively. Phenotypic DDST identified 48% isolates as ESBLs producers. Genotypic characterization identified 70%, 74.4% and 49% prevalence of CTXM-1, TEM-1 and CTXM-15 genes respectively. One isolate was observed exhibiting co-existence of all ESBL genes. TEM-1 + CTXM-1 and TEM-1 + CTXM-1 + CTXM-15 + OXA-1 gene patterns were dominant among ESBLs. For carbapenem-resistance, 14% isolates indicated the presence of KPC whereas GES and VIM was detected in 7% and 3.4% isolates, respectively. In conclusion, our results present a high prevalence of extensively drug resistant UPEC isolates with a considerable percentage of ESBL producers. These findings propose the need of continuous surveillance for antimicrobial resistance and targeted antimicrobial therapy.

Multidrug-Resistant ESBL-Producing E. coli in Clinical Samples from the UK

Globally, cephalosporin therapy failure is a serious problem for infection control. One causative agent of cephalosporin-resistant infections is multidrug-resistant (MDR) E. coli producing extended-spectrum β-lactamases (ESBLs) and/or plasmid-encoded AmpC (pAmpC) β-lactamases. We evaluated the occurrence of ESBL/pAmpC genetic determinants in phenotypically MDR E. coli isolated from clinical samples of blood, faeces, ear effusion, urine and sputum from a UK hospital. Phenotypic resistance profiling for 18 antibiotics (from seven classes) showed that 32/35 isolates were MDR, with resistance to 4-16 of the tested antibiotics. Of the isolates, 97.1% showed resistance to ampicillin, 71.4% showed resistance to co-amoxiclav, cefotaxime, ceftazidime and ceftiofur, and 68.5% showed resistance to cefquinome. bla_CTX-M, bla_TEM and bla_OXA-1 genes were detected in 23, 13 and 12 strains, respectively, and Intl1 was detected in 17 isolates. The most common subtypes among the definite sequence types were CTX-M-15 (40%) and TEM-1 (75%). No E. coli isolates carried pAmpC genes. Significant correlations were seen between CTX-M carriage and cefotaxime, ceftiofur, aztreonam, ceftazidime and cefquinome resistance; between bla_CTX-M, bla_TEM and bla_OXA-1 carriage and ciprofloxacin resistance; and between Intl1 carriage and trimethoprim/sulfamethoxazole resistance. Thus, MDR phenotypes may be conferred by a relatively small number of genes. The level and pattern of antibiotic resistance highlight the need for better antibiotic therapy guidelines, including reduced use and improved surveillance.

Initial empirical antibiotics of non-carbapenems for ESBL-producing E. coli and K. pneumoniae bacteremia in children: a retrospective medical record review

BACKGROUND

The efficacy of non-carbapenems as an empirical antibiotic for extended-spectrum β-lactamases (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bacteremia in children remains controversial. We compared clinical and microbial outcomes according to the types of empirical antibiotics for treating pediatric patients with ESBL-producing E. coli and K. pneumoniae bacteremia.

METHODS

Data from pediatric patients aged ≤ 18 years who were hospitalized with monomicrobial ESBL-producing E. coli or K. pneumoniae bacteremia at Asan Medical Center Children's Hospital, Seoul, Korea between January 2014 and May 2019 were analyzed retrospectively. The impact of empirical therapy was assessed as 30-day all-cause mortality and 2-day microbiological outcomes evaluated by the sterility of blood cultures collected on day 2 after empirical antibiotic administration. Logistic regression analysis was used to control for the effects of confounding variables.

RESULTS

A total of 53 patients with bacteremia caused by ESBL-producing E. coli (n = 29) and K. pneumoniae (n = 24) were included in this study; the median age was 3.6 years, and all had underlying comorbidities. As empirical antibiotics, 27 patients were treated with meropenem, and non-carbapenem agents were administered to 26 patients; 84.6% (22/26) were converted to carbapenem antibiotics as the definitive antibiotic by day 2 after empirical antibiotic administration. Overall, the 30-day all-cause mortality of ESBL-producing E. coli and K. pneumoniae bacteremia was 17.0% (9/53). After adjustment, there was no statistically significant association of use of a non-carbapenem agent as an empirical antibiotic with microbiological failure on day 2 and 30-day all-cause mortality [adjusted odds ratio (OR) 1.0; 95% confidence interval (CI) 0.22-4.88, and adjusted OR 0.1; 95% CI 0.01-1.56].

CONCLUSIONS

The empirical use of non-carbapenems might not be a risk factor for mortality and early microbiological outcomes in pediatric patients with ESBL-producing E. coli and K. pneumoniae BSI if early transition to appropriate antimicrobial therapy was possible.

Adult intracranial infection caused by an extended-spectrum-beta-lactamase-producing strain of hypervirulent Klebsiella pneumoniae: a case report

Background

Klebsiella pneumoniae is a conditional pathogen related to several infectious diseases. Few studies reported Klebsiella pneumoniae meningitis in the Chinese population, guidelines on diagnosis and treatment of Klebsiella pneumoniae meningitis should be considered due to its high lethality. Here, we report a case of adult intracranial infection caused by extended-spectrum-beta-lactamase (ESBL)-producing hypervirulent Klebsiella pneumoniae (hvKP) in a 65-year-old female, providing new insight for clinical awareness and epidemiological surveillance for ESBL-producing hvKP infection.

Case Description

A 65-year-old female who had a recurrent fever for more than 1 month, and vomiting for 1 week was admitted to our hospital. The computed tomography (CT) results and laboratory results indicated systematic infection, and the blood culture confirmed the infection of Klebsiella pneumoniae. A combination of antibiotics including vancomycin, caspofungin, dexamethasone, and posaconazole oral suspension was given to the patient. Further, she exhibited a convulsion with unconsciousness, the CT revealed lacunar infarction and encephalomalacia. The following physical examination showed slight neck resistance, a weak light response of the eye, low muscle tension, suspicious left Babinski sign (+), and right Babinski sign (−). The CT and cerebrospinal fluid (CSF) analyses confirmed the diagnosis of intracranial infection caused by Klebsiella pneumoniae. We employed CSF microbial metagenomic next-generation sequencing (mNGS) was employed and the results suggested the high sequence of Klebsiella pneumoniae with drug-resistant gene SHV-type beta-lactamases (blaSHV). Subsequently, 2 g meropenem every 8 hours (q8h) prolonged for 3 hours was applied to treat intracranial infection, and her body temperature and infectious manifestations were gradually relieved. The CT results represented that pulmonary edema and pleural effusion were gradually dissipated and absorbed. Based on the improvement of clinical manifestations, the patient was discharged from the hospital and a close follow-up was conducted.

Conclusions

An ESBL-producing strain of hvKP could lead to invasive infection such as severe intracranial infection, with a relatively favorable prognosis. The outcome of the disease caused by Klebsiella pneumoniae infection is firmly related to the phenotypic features, for instance, virulence factors and antibiotic susceptibility. Due to its high lethality, timely empiric anti-infection therapy and close surveillance are necessary for patients with Klebsiella pneumoniae infection in the clinic.

Extended-spectrum beta-lactamases among Klebsiella pneumoniae from Iraqi patients with community-acquired pneumonia

OBJECTIVE

Beta-lactams resistance is a major clinical problem in treating pneumonia. This study aimed to detect the extended-spectrum beta-lactamases (ESBL) genes in Klebsiella pneumoniae among patients with community-acquired pneumonia (CAP) in Al-Najaf City, Iraq.

METHODS

A total of 511 sputum samples were obtained from all suspected patients with CAP in Al-Najaf City, Iraq, from March 2020 to September 2020. Sputum samples were subjected to microbiological tests. The disk diffusion method was used to test antibiotic sensitivity. Production of ESBLs was identified using phenotypic and genotypic methods.

RESULTS

The total prevalence of K. pneumoniae was 31.9% (163/511). Using CHROM agar, 41 (25.2%) isolates were ESBL producers. The imipenem 0.0% (n=0/41) and norfloxacin 0.0% (n=0/41) were the most effective antibiotics. The multiplex polymerase chain reaction showed that 46.3% (n=19/41) of isolates harbored ESBL genes. Out of 19 ESBL producers, 47.4% and 15.8% harbored blaCTX-M and blaSHV, respectively. While blaCTX-M and blaSHV genes were detected in 7 (36.8%) isolates, simultaneously.

CONCLUSIONS

The imipenem and norfloxacin can be used in empirical treatment of K. pneumoniae isolates in Iraq. The emergence of K. pneumoniae strains harboring ESBL resistance genes necessitates the development of a regular surveillance program to prevent the spreading of these isolates more in Iraqi health care systems.

Epidemiology, Environmental Risks, Virulence, and Resistance Determinants of Klebsiella pneumoniae From Dairy Cows in Hubei, China

Klebsiella pneumoniae (K. pneumoniae) is an opportunistic pathogen, which causes serious infections in humans and animals. To investigate the antimicrobial resistance pattern and virulence profile of K. pneumoniae, a total of 887 samples were collected from both the healthy and mastitis cows and the bedding, feed, feces, air, drinking water, spraying water, washing water, and milk cup swabs from five dairy farms in Hubei, China, during 2019 and 2020. K. pneumoniae was isolated and identified using PCR of the khe and 16S rDNA sequencing. A genotypic characterization was performed for K. pneumoniae isolates using wzi typing and multilocus sequence typing (MLST). Antimicrobial resistances were confirmed using broth microdilution against 17 antimicrobial agents and resistance and virulence genes were determined by PCR. The prevalence of K. pneumoniae was 26.94% (239/887) distributed in 101 wzi allele types (199/239, 83.26%) and 100 sequence types (STs) (209/239, 87.45%), including 5 new wzi allele type and 25 new STs. Phylogenetic analysis showed that K. pneumoniae isolated from milk, nipple swab, feed, and feces is classified in the same clone complex. By comparing with the PubMLST database, at least 67 STs have the risk of spreading in different species and regions. Interestingly, 60 STs have been isolated from humans. The isolates were highly sensitive to meropenem and colistin, but resistant to ampicillin (100%), sulfisoxazole (94.56%), cephalothin (47.28%), streptomycin (30.13%), and so on. Noteworthy, multidrug-resistant (MDR) rate was found to be 43.93% in this study. By PCR, 30 of 68 antimicrobial resistance (AMR) genes were identified; the prevalence rate of blaTEM, blaSHV, strA, strB, aadA1, and aac(6′)-Ib-cr was more than 50%. Eleven CTX-M-producing K. pneumoniae were found. The detection rate of fimH, mrkD, uge, wabG, entB, iutA, iroN, and ureA was over 85%. This study reinforces the epidemiological importance of K. pneumoniae in food-producing animals in Hubei. The emergence and spread of environmental MDR K. pneumoniae may pose a potential threat to food safety and public health.

Prognostic factors of OXA-48 carbapenemase-producing Klebsiella pneumoniae infection in a tertiary-care Spanish hospital: A retrospective single-center cohort study

OBJECTIVES

To describe the determinants of outcome of infections due to OXA-48 carbapenemase-producing Klebsiella pneumoniae (OXA-48-Kp).

METHODS

A retrospective cohort study of 117 episodes of OXA-48-Kp infection were conducted. Multivariate Cox models identified factors predicting 14-day clinical response and 30-day all-cause mortality.

RESULTS

Seventy-seven (65.8%) isolates were susceptible to imipenem/meropenem. 14-day clinical response and 30-day mortality rates were 41.9% and 28.2%. Catheter-related bloodstream infection (adjusted hazard ratio [aHR]: 8.33; 95% confidence interval [95%CI]: 3.19-21.72; P-value <0.001), urinary tract infection (aHR: 3.04; 95%CI: 1.39-6.66; P-value = 0.006) and early appropriate treatment (aHR: 1.77; 95%CI: 0.97-3.22; P-value = 0.064) predicted clinical response, whereas severe sepsis had a deleterious impact (aHR: 0.22; 95%CI: 0.10-0.50; P-value <0.001). Lower respiratory tract infection (aHR: 6.58; 95%CI: 2.83-15.29; P-value <0.001) and bloodstream infection (aHR: 2.33; 95%CI: 1.05-5.15; P-value = 0.037) were associated with 30-day mortality, whereas definitive therapy including ≥1 active agent (aHR: 0.26; 95%CI: 0.11-0.63; P-value = 0.003) and source control (aHR: 0.35; 95%CI: 0.14-0.91; P-value = 0.030) were protective. Combination therapy did not seem to be associated with better outcomes.

CONCLUSIONS

Appropriate antimicrobial treatment was protective for 30-day mortality in OXA-48-Kp infections. Carbapenems are usually active, whereas combination therapy appeared not to confer additional benefit.

A Descriptive Analysis of Urinary ESBL-Producing-Escherichia coli in Cerdanya Hospital

Urinary tract infections caused by extended-spectrum β-lactamase Escherichia coli (ESBL-EC) are increasing worldwide and are a current concern because treatment options are often limited. This study investigated antimicrobial susceptibility, antimicrobial resistance genes (ARGs), and the biological diversity of urinary ESBL-EC isolates at Cerdanya Hospital, a European cross-border hospital that combines French and Spanish healthcare models. Bacterial identification and susceptibility were determined using the Microscan WalkAway^® system and ESBL production was examined by the double-disk synergy method. Isolates were sequenced using the Ion S5^™ next-generation sequencing system, with the whole-genome sequences then assembled using SPADEs software and analyzed using PubMLST, ResFinder, FimTyper, PlasmidFinder, and VirulenceFinder. A phylogenetic analysis was performed by constructing an assembly-based core-SNV alignment, followed by a phylogenetic tree constructed using Parsnp from the Harvest suite. All isolates studied were multidrug-resistant and could be classified into 19 different sequence types characterized by a high genetic diversity. The most prevalent ESBL-enzymes were CTX-M-14 and CTX-M-15. High-risk international clones (ST131, ST10, and ST405) were also identified. The results demonstrated the absence of a single predominant clone of ESBL-MDR-EC at Cerdanya Hospital.

Early Response of Antimicrobial Resistance and Virulence Genes Expression in Classical, Hypervirulent, and Hybrid hvKp-MDR Klebsiella pneumoniae on Antimicrobial Stress

Klebsiella pneumoniae is an increasingly important hospital pathogen. Classical K. pneumoniae (cKp) and hypervirulent K. pneumoniae (hvKp) are two distinct evolutionary genetic lines. The recently ongoing evolution of K. pneumoniae resulted in the generation of hybrid hvKP-MDR strains. K. pneumoniae distinct isolates (n = 70) belonged to 20 sequence types with the prevalence of ST395 (27.1%), ST23 (18.6%), ST147 (15.7%), and ST86 (7.1%), and 17 capsular types with the predominance of K2 (31.4%), K57 (18.6%), K64 (10.0%), K1 (5.7%) were isolated from patients of the Moscow neurosurgery ICU in 2014-2019. The rate of multi-drug resistant (MDR) and carbapenem-resistant phenotypes were 84.3% and 45.7%, respectively. Whole-genome sequencing of five selected strains belonging to cKp (ST395^K47 and ST147^K64), hvKp (ST86^K2), and hvKp-MDR (ST23^K1 and ST23^K57) revealed bla_SHV, bla_TEM, bla_CTX, bla_OXA-48, and bla_NDM beta-lactamase genes; acr, oqx, kpn, kde, and kex efflux genes; and K. pneumoniae virulence genes. Selective pressure of 100 mg/L ampicillin or 10 mg/L ceftriaxone induced changes of expression levels for named genes in the strains belonging to cKp, hvKp, and hybrid hvKp-MDR. Obtained results seem to be important for epidemiologists and clinicians for enhancing knowledge about hospital pathogens.