Acute Exacerbation of Chronic Obstructive Pulmonary Disease Due to Carbapenem-Resistant Klebsiella pneumoniae-Induced Pneumonia: Clinical Features and Prognostic Factors.

Purpose: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is closely related to respiratory tract infection. The aim of this study was to investigate the clinical features and prognostic factors of CRKP-induced pneumonia in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients. Methods: A single-centre, retrospective case-control study on COPD patients hospitalized for acute exacerbation and CRKP-induced pneumonia was conducted from January 1, 2016, to December 31, 2022. The mortality rate of acute exacerbation due to CRKP-induced pneumonia was investigated. The patients were divided into the CRKP-induced pneumonic acute exacerbation (CRKPpAE) group and the non-CRKP-induced pneumonic acute exacerbation (non-CRKPpAE) group, and the clinical characteristics and prognostic factors were compared using univariate analysis and multivariate analysis. Results: A total of 65 AECOPD patients were included, composed of 26 patients with CRKPpAE and 39 patients with non-CRKPpAE. The mortality rate of CRKPpAE was 57.69%, while non-CRKPpAE was 7.69%. Compared with non-CRKPpAE, a history of acute exacerbation in the last year (OR=8.860, 95% CI: 1.360-57.722, p=0.023), ICU admission (OR=11.736, 95% CI: 2.112-65.207, p=0.005), higher NLR levels (OR=1.187, 95% CI: 1.037-1.359, p=0.013) and higher D-dimer levels (OR=1.385, 95% CI: 1.006-1.905, p=0.046) were independently related with CRKPpAE. CRKP isolates were all MDR strains (26/26, 100%), and MDR strains were also observed in non-CRKP isolates (5/39, 12.82%). Conclusion: Compared with non-CRKPpAE, CRKPpAE affects the COPD patient's condition more seriously and significantly increases the risk of death.

Analysis of distribution and antibiotic resistance of Gram-positive bacteria isolated from a tertiary-care hospital in southern China: an 8-year retrospective study.

Objective: Due to the severe drug resistance situation of Gram-negative bacteria, especially Gram-negative enterobacter, relatively little attention has been paid to the changes in Gram-positive bacteria species and drug resistance. Therefore, this study analyzed the prevalence and drug resistance of Gram-positive bacteria in a general tertiary-care hospital from 2014 to 2021, in order to discover the changes in Gram-positive bacteria distribution and drug resistance that cannot be easily identified, inform clinicians in their respective regions when selecting antimicrobial agents, and to provide the basis for the diagnosis of Gram-positive bacterial infection, and for the comprehensive and multi-pronged prevention and control of drug-resistant bacteria. Methods: A retrospective study was conducted on Gram-positive bacteria isolated from patients presented to a general tertiary-care hospital from January 2014 to December 2021. A total of 15,217 Gram-positive strains were analyzed. Results: During the 8-year period, the total number and the species of Gram-positive bacteria isolated from clinic increased continuously. The seven most common species were Streptococcus pneumoniae (21.2%), Staphylococcus aureus (15.9%), Enterococcus faecium (20.6%), Enterococcus faecalis (14.0%), and Staphylococcus epidermidis (7.8%), Staphylococcus haemolyticus (4.8%), Streptococcus agalactiae (3.6%). The isolation rates of Staphylococcus aureus and Streptococcus agalactiae increased, and the isolation rate of Enterococcus faecium decreased. The resistance rates of Staphylococcus aureus to erythromycin, clindamycin, tetracycline, rifampicin and furantoin decreased obviously. The resistance rates of Streptococcus pneumoniae to cefepime (non-meningitis) and ceftriaxone (meningitis) decreased significantly. The resistance rates of Enterococcus faecium to penicillin, ampicillin, erythromycin, levofloxacin, ciprofloxacin and furantoin rose rapidly from 50.3, 47.6, 71.5, 44.9, 52.3, and 37.5% in 2014 to 93.1, 91.6, 84.9, 86.8, 86.8, and 60.0% in 2021, respectively. Conclusion: The total number and the species of Gram-positive bacteria isolated during the 8-year period increased continuously. Streptococcus pneumoniae and Staphylococcus aureus are the main causes of positive bacterial infections in this hospital. The resistance rates of Enterococcus faecium to a variety of commonly used antibiotics increased significantly. Therefore, it is very important to monitor the distribution of bacteria and their resistance to antibiotics to timely evaluate and identify changes in drug resistance that are not easily detected.

Fluviispira vulneris sp. nov., isolated from human wound secretions.

Human infections by environmental bacteria is becoming an increasing problem and has become a matter of great concern due to the adverse effects worldwide. In this study, we reported a new environmental pathogen. Isolate GX5518T was a novel Gram-negative, aerobic, non-motile, pleomorphic and red-pigmented bacterium, was isolated from human wound secretions (GuangXi, People's Republic of China). Growth occurred at pH 6.0-8.0 (optimum, pH 7.0) and 10-37 °C (optimum, 28-32 °C) with 0-1.5% (w/v) NaCl in R2A agar. Comparative analysis of the 16S rRNA gene sequences revealed that isolate GX5518T was closely related to Fluviispira sanaruensis JCM 31447T (99.73%) and Fluviispira multicolorata 33A1-SZDPT (98.49%). However, the estimated ANI values of the isolate GX5518T compared to the F. sanaruensis JCM 31447T and F. multicolorata 33A1-SZDPT were 88.67% and 77.35%, respectively. The estimated dDDH, ANI and AAI values between isolate GX5518T and its closely related strains were below the threshold values generally considered for recognizing a new species. The genome size was 3.6 Mbp and the DNA G + C content was 33.1%. The predominant fatty acids (> 5%) in GX5518T cells were iso-C15:0, C16:0, C17:0, C17:1 ω8c and C16:1 ω7c/C16:1 ω6c. The major menaquinone was MK-8 (86.9%). The polar lipids were phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and three unknown lipids (L1-3). The chemical composition was different from that of the F. sanaruensis JCM 31447T. Comparative genomics analysis between isolate GX5518T and its related strains revealed that there were a number of genes involved in resistance to antibiotics and toxic compounds in isolate GX5518T, which were responsible for the copper homeostasis, cobalt-zinc-cadmium resistance, resistance to fluoroquinolones, and zinc resistance. Based on the phenotypic, chemotaxonomic, and genomic analyses, isolate GX5518T (= CGMCC 1.18685T = KCTC 82149T) represents a novel species of the genus Fluviispira, for which the name Fluviispira vulneris sp. nov. is proposed.

Characteristics of ST11 KPC-2-producing carbapenem-resistant hypervirulent Klebsiella pneumoniae causing nosocomial infection in a Chinese hospital.

BACKGROUND: The purpose of our study is to analyze the microbiological and clinical characteristics of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) that causes nosocomial infection. METHODS: We collected the carbapenem-resistant K. pneumoniae (CRKP) strains that caused nosocomial infection in a hospital in China and collected the relevant clinical data. We characterized these strains for their antimicrobial and virulence-associated phenotype and genotype and analyzed the clonal relatedness. We screened hypervirulent strains and compared them with non-hypervirulent strains. RESULTS: We retrospectively analyzed 62 CRKP strains that caused nosocomial infection in a tertiary hospital within 1 year, of which 41 (41/62, 66.1%) CRKP were considered as CR-hvKP. All CR-hvKP strains were multi-drug resistance (MDR) and the vast majority of isolates (39/41, 95.1%) were ST11 KPC-2-producing strains. Two hypermucoviscous isolates and 4 capsular types were found in 41 CR-hvKP. Twenty-nine isolates (29/41, 70.7%) showed hypervirulence in Galleria mellonella infection model. PFGE showed that ST11-KL47 CR-hvKP and ST11-KL64 CR-hvKP exhibited a high degree of clonality, while non-hypervirulent strains were not significant. CR-hvKP had higher positive rates of blaKPC-2 and blaCTX-M-65 and higher levofloxacin resistance (p < 0.001, p = 0.005 and p = 0.046, respectively) when compared to the non-hypervirulent strains. There was no significant difference between the two groups in terms of in-hospital mortality (7/41, 17.1% vs 5/21, 23.8%, p = 0.743). CONCLUSION: Our research finds that ST11 KPC-2-producing CR-hvKP is the main type of CRKP that caused nosocomial infection, and clonal spread has occurred. We provide more information about CR-hvKP in health care.

Pigmentibacter ruber gen. nov., sp. nov., a novel bacterium of the family Silvanigrellaceae isolated from human blood.

A Gram-negative, aerobic, non-motile, pleomorphic, red-pigmented bacterium, designated HNSRY-1T, was isolated from the blood sample of a near drowning patient in Republic of China. Strain HNSRY-1T grew at 15-37 °C (optimum, 35 °C), with pH 6.0-8.0 (optimum, pH 7.0) and 0-1.5% (W/V) NaCl (optimum, 1%). The predominant fatty acids (> 5%) in HNSRY-1T cells are iso-C15:0, C17:0, C17:1 ω8c, C16:0, and C16:1 ω6c/C16:1 ω7c. The major respiratory quinone is MK-8. The polar lipids are phosphatidylglycerol, phosphatidylethanolamine, three unidentified lipids and four unidentified aminolipids. The 16S rRNA gene sequence-based phylogenetic analysis indicated that strain HNSRY-1T belonged to the family Silvanigrellaceae, forming a distinct phylogenetic line distantly related (< 96.4% sequence similarity) to known species of the family. The ANI values of strain HNSRY-1T compared to the closely related species were below the determined genus division threshold limit (92-94% ANI), and AAI values were lower than the determined genus division threshold limit (80% AAI). Whole genome sequencing revealed a genome size of 3.63 Mb with a DNA G + C content at 29.6%. The half-lethal dose of strain HNSRY-1T on KM mice is about 1.12 × 108 CFU/ml. Virulence gene analysis showed that the pathogenicity of HNSRY-1T may be related to tufA, htpB, katA, wbtL, wbtM, pseB, clpP, cheY, cheV3, acpXL, pilB, fliN, ggt, flgG, fliP, nueB, pseA, bioB and flil. Based on these findings from the polyphasic taxonomy studies, a novel genus and species of the family Silvanigrellaceae. Pigmentibacter ruber gen. nov., sp. nov. is proposed, with type strain HNSRY-1T (= KCTC 72920T = CGMCC 1.18525T).

Evolution of hypervirulence in carbapenem-resistant Klebsiella pneumoniae in China: a multicentre, molecular epidemiological analysis.

OBJECTIVES: Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) have been increasingly reported in China. Here, a multicentre, longitudinal surveillance study on CR-hvKP is described. METHODS: We retrospectively investigated carbapenem-resistant K. pneumoniae (CRKP) in 56 centres across China during 2015-17 and screened the virulence genes (iucA, iroN, rmpA and rmpA2) for the presence of virulence plasmids. Hypermucoviscosity, serum killing and Galleria mellonella lethality experiments were conducted to identify CR-hvKP among strains with all four virulence genes. Capsule typing, fitness and plasmid features of CR-hvKP were also investigated. RESULTS: A total of 1052 CRKP were collected. Among these, 34.2% (360/1052) carried virulence genes and 72 of them had all four of the virulence genes tested. Fifty-five (76.4%) were considered to be CR-hvKP using the G. mellonella infection model, with KPC-2-producing K64-ST11 being the most common type (80%, 44/55). Prevalence of CR-hvKP differed greatly between regions, with the highest in Henan (25.4%, 17/67) and Shandong (25.8%, 25/97). A significant increase in CR-hvKP among KPC-2-producing ST11 strains was observed, from 2.1% (3/141) in 2015 to 7.0% (23/329) in 2017 (P=0.045). Alarmingly, compared with classic CRKP, no difference in growth was found among CR-hvKP (P=0.7028), suggesting a potential risk for dissemination. The hybrid virulence and resistance-encoding plasmid evolved from pLVPK and the resistance plasmid harbouring blaKPC-2, indicating evolution existed between the hypervirulence and hyper-resistance plasmid. CONCLUSIONS: CR-hvKP were more frequently detected than previously assumed, especially among KPC-2-producing ST11. Dissemination of hypervirulence could be extremely rapid due to limited fitness cost. Also, the evolution of resistance genes into hypervirulence plasmids was identified, presenting significant challenges for public health and infection control.

Phenotypic and Genotypic Characterization of Carbapenem-resistant Enterobacteriaceae: Data From a Longitudinal Large-scale CRE Study in China (2012-2016).

Background: Carbapenem-resistant Enterobacteriaceae (CRE) strains are a major threat to global health. The development of effective control measures requires more detailed phenotypic and genotypic characterization of CRE. Methods: CRE isolates were collected from 65 hospitals in 25 provinces across China between January 1, 2012, and December 31, 2016. The isolates were characterized by antimicrobial susceptibility testing and multilocus sequence typing. Genes encoding carbapenemases, mobilized colistin resistance (mcr-1), and ß-lactamases were detected by polymerase chain reaction and DNA sequencing. Results: A total of 1801 independent CRE isolates (1201 Klebsiella pneumoniae, 282 Escherichia coli, and 179 Enterobacter cloacae) were collected during the study period. Overall, 96.9%, 89.7%, 54.5%, 49.9%, and 40% of CRE strains were susceptible to colistin, tigecycline, amikacin, minocycline, and fosfomycin, respectively. Notably, 1091/1201 (91%) K. pneumoniae, 225/282 (80%) E. coli, and 129/179 (72%) E. cloacae harbored carbapenemase gene. K. pneumoniae carbapenemase (KPC) was predominant in K. pneumoniae (77%), whereas New Delhi metallo-ß-lactamase (NDM) was predominant in E. coli (75%) and E. cloacae (53%). The mcr-1 gene was detected in 13 NDM-carrying E. coli isolates (4.6%). Sequence type (ST)11 and ST167 were predominant among the 100 K. pneumoniae and 47 E. coli STs, respectively. KPC-ST11, which accounted for 64% of K. pneumoniae isolates, had higher levels of resistance than non-ST11 strains to aztreonam, fosfomycin, and amikacin (P < .001). The proportions of KPC and NDM enzymes in CRE increased from 2012 to 2016 (54%-59% and 12%-28%, respectively). Conclusions: The number of CRE strains harboring carbapenemase is increasing. KPC-ST11 K. pneumoniae, the predominant strain, shows a reduced susceptibility to most available antibiotics.