Objective: To obtain the diversity and abundance of fast-growing bacteria in the surface water of the northeast coast of Hainan Island in China, different cultivation methods were employed. This study also aims to provide a reference for isolating bacterial samples from seawater sources and preventing marine-derived pathogens. Methods: Based on the principles of taxonomic design, surface seawater samples were collected from six locations along the northeast coast of Hainan Island in China in March, June, October, and December 2021. Then, bacterial enrichment was performed based on traditional cultivation methods for Salmonella, Vibrio, Burkholderia pseudomallei, Actinomycetes, and general marine bacteria. After that, bacterial species identification was conducted by 16S rDNA amplicon sequencing and metagenomic sequencing. Results: A total of 1 151 fast-growing cultivable bacteria belonging to 66 genera and 213 species were identified using five different culture protocols. In different cultivation protocols, Bacillus and Klebsiella demonstrated extensive discriminatory advantages and ranked among the top genera in terms of abundance. Protocol 1 had Escherichia, Klebsiella, and Citrobacter as dominant genera. Pathogenic bacteria detected by protocol 1 included Klebsiella pneumoniae and Escherichia coli, with 37 and 29 strains respectively, while Salmonella enterica was uniquely detected with seven isolates. Proteus, Enterococcus, and Providencia were the dominant genera in protocol 2, and Proteus mirabilis was the most abundant pathogenic bacteria detected with 66 isolates. Vibrio cholerae was uniquely detected with six isolates at a higher abundance. Klebsiella, Escherichia, and Acinetobacter were the dominant genera in protocol 3, and Klebsiella pneumoniae was the most abundant pathogenic bacteria detected with 53 isolates, while Acinetobacter nosocomialis was uniquely detected with seven isolates. Vibrio and Pseudoalteromonas were the dominant genera in protocol 4, and they showed advantages in isolating and cultivating Marine-derived Vibrio. Exiguobacterium, Staphylococcus, and Bacillus were the dominant genera in protocol 5. Bacillus cereus and Lactococcus lactis were the most abundant pathogenic bacteria detected with 20 and 15 isolates, respectively, while Lactococcus lactis was uniquely detected at higher abundance. Metagenomic sequencing showed that Klebsiella pneumoniae was significantly dominant with a gene abundance of 51.11%, followed by Alcanivorax sp. at 12.57%. Conclusion: The surface water of the northeast coast of Hainan Island in China exhibits a rich diversity of bacteria, with Klebsiella pneumoniae being highly abundant in the studied area. Different cultivation methods demonstrate distinct selective advantages in culturing bacterial genera and pathogens. Therefore, it is necessary to optimize cultivation conditions for specific marine bacteria.
Humans ; Water ; Bacteria/genetics* ; Seawater/microbiology* ; Escherichia coli ; Enterococcus ; Klebsiella pneumoniae ; China

Objective: To obtain the diversity and abundance of fast-growing bacteria in the surface water of the northeast coast of Hainan Island in China, different cultivation methods were employed. This study also aims to provide a reference for isolating bacterial samples from seawater sources and preventing marine-derived pathogens. Methods: Based on the principles of taxonomic design, surface seawater samples were collected from six locations along the northeast coast of Hainan Island in China in March, June, October, and December 2021. Then, bacterial enrichment was performed based on traditional cultivation methods for Salmonella, Vibrio, Burkholderia pseudomallei, Actinomycetes, and general marine bacteria. After that, bacterial species identification was conducted by 16S rDNA amplicon sequencing and metagenomic sequencing. Results: A total of 1 151 fast-growing cultivable bacteria belonging to 66 genera and 213 species were identified using five different culture protocols. In different cultivation protocols, Bacillus and Klebsiella demonstrated extensive discriminatory advantages and ranked among the top genera in terms of abundance. Protocol 1 had Escherichia, Klebsiella, and Citrobacter as dominant genera. Pathogenic bacteria detected by protocol 1 included Klebsiella pneumoniae and Escherichia coli, with 37 and 29 strains respectively, while Salmonella enterica was uniquely detected with seven isolates. Proteus, Enterococcus, and Providencia were the dominant genera in protocol 2, and Proteus mirabilis was the most abundant pathogenic bacteria detected with 66 isolates. Vibrio cholerae was uniquely detected with six isolates at a higher abundance. Klebsiella, Escherichia, and Acinetobacter were the dominant genera in protocol 3, and Klebsiella pneumoniae was the most abundant pathogenic bacteria detected with 53 isolates, while Acinetobacter nosocomialis was uniquely detected with seven isolates. Vibrio and Pseudoalteromonas were the dominant genera in protocol 4, and they showed advantages in isolating and cultivating Marine-derived Vibrio. Exiguobacterium, Staphylococcus, and Bacillus were the dominant genera in protocol 5. Bacillus cereus and Lactococcus lactis were the most abundant pathogenic bacteria detected with 20 and 15 isolates, respectively, while Lactococcus lactis was uniquely detected at higher abundance. Metagenomic sequencing showed that Klebsiella pneumoniae was significantly dominant with a gene abundance of 51.11%, followed by Alcanivorax sp. at 12.57%. Conclusion: The surface water of the northeast coast of Hainan Island in China exhibits a rich diversity of bacteria, with Klebsiella pneumoniae being highly abundant in the studied area. Different cultivation methods demonstrate distinct selective advantages in culturing bacterial genera and pathogens. Therefore, it is necessary to optimize cultivation conditions for specific marine bacteria.
Humans ; Water ; Bacteria/genetics* ; Seawater/microbiology* ; Escherichia coli ; Enterococcus ; Klebsiella pneumoniae ; China

In recent years, there have been increasing reports of KPC-producing Klebsiella pneumoniae in Korea. The modified Hodge test can be used as a phenotypic screening test for class A carbapenamase (CAC)-producing clinical isolates; however, it does not distinguish between carbapenemase types. The confirmation of type of CAC is important to ensure optimal therapy and to prevent transmission. This study applied a novel multiplex PCR assay to detect and differentiate CAC genes in a single reaction. Four primer pairs were designed to amplify fragments encoding 4 CAC families (SME, IMI/NMC-A, KPC, and GES). The multiplex PCR detected all genes tested for 4 CAC families that could be differentiated by fragment size according to gene type. This multiplex PCR offers a simple and useful approach for detecting and distinguishing CAC genes in carbapenem-resistant strains that are metallo-beta-lactamase nonproducers.
Bacterial Proteins/*genetics/metabolism ; DNA Primers/metabolism ; Databases, Genetic ; Humans ; Klebsiella Infections/microbiology ; Klebsiella pneumoniae/genetics/isolation & purification/metabolism ; *Multiplex Polymerase Chain Reaction ; beta-Lactamases/*genetics/metabolism

Objective: The study investigated the clinical distribution, antimicrobial resistance and epidemiologic characteristics of hypervirulent Carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) in a hospital in Henan Province to provide a scientific basis for antibiotic use and nosocomial infection prevention and control. Methods: A retrospective analysis of the clinical data from the cases was carried out in this study. Clinical data of patients infected with the CRKP strain isolated from the clinical microbiology laboratory of Henan Provincial Hospital of Traditional Chinese Medicine from January 2020 to December 2022 were retrospectively analyzed. A string test, virulence gene screening, serum killing, and a G. mellonella infection model were used to screen hv-CRKP isolates. The clinical characteristics of hv-CRKP and the drug resistance rate of hv-CRKP to twenty-five antibiotics were analyzed using WHONET 5.6. Carbapenemase phenotypic characterization of the hv-CRKP was performed by colloidal gold immunochromatographic assay, and Carbapenemase genotyping, multi-locus sequence typing (MLST) and capsular serotyping of hv-CRKP isolates were performed by PCR and Sanger sequencing. Results: A total of non-duplicate 264 CRKP clinical isolates were detected in the hospital from 2020 to 2022, and 23 hv-CRKP isolates were detected, so the corresponding detection rate of hv-CRKP was 8.71% (23/264). The hv-CRKP isolates in this study were mainly from the intensive care unit (10/23) and neurosurgery department (8/23), and the main sources of hv-CRKP isolates were sputum (10/23) and bronchoalveolar lavage fluid (6/23). The hv-CRKP isolates in this study were highly resistant to β-lactam antibiotics, fluoroquinolones and aminoglycosides, and were only susceptible to colistin, tigecycline and ceftazidime/avibactam. The detection rate of the blaKPC-2 among 23 hv-CRKP isolates was 91.30% (21/23) and none of the class B and class D carbapenemases were detected. Results of MLST and capsular serotypes showed that ST11 type hv-CRKP was the dominant strain in the hospital, accounting for 56.52% (13/23), and K64 (9/13) and KL47 (4/13) were the major capsular serotypes. Conclusion: The hv-CRKP isolates from the hospital are mainly from lower respiratory tract specimens from patients admitted to the intensive care department and the drug resistance is relatively severe. The predominant strains with certain polymorphisms are mainly composed of the KPC-2-producing ST11-K64 and ST11-KL47 hv-CRKP isolates in the hospital.
Humans ; Klebsiella pneumoniae/genetics* ; Multilocus Sequence Typing ; Retrospective Studies ; Klebsiella Infections/drug therapy* ; Anti-Bacterial Agents/therapeutic use* ; Hospitals ; Carbapenem-Resistant Enterobacteriaceae/genetics* ; Microbial Sensitivity Tests ; Carbapenems/pharmacology*

Objective: The study investigated the clinical distribution, antimicrobial resistance and epidemiologic characteristics of hypervirulent Carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) in a hospital in Henan Province to provide a scientific basis for antibiotic use and nosocomial infection prevention and control. Methods: A retrospective analysis of the clinical data from the cases was carried out in this study. Clinical data of patients infected with the CRKP strain isolated from the clinical microbiology laboratory of Henan Provincial Hospital of Traditional Chinese Medicine from January 2020 to December 2022 were retrospectively analyzed. A string test, virulence gene screening, serum killing, and a G. mellonella infection model were used to screen hv-CRKP isolates. The clinical characteristics of hv-CRKP and the drug resistance rate of hv-CRKP to twenty-five antibiotics were analyzed using WHONET 5.6. Carbapenemase phenotypic characterization of the hv-CRKP was performed by colloidal gold immunochromatographic assay, and Carbapenemase genotyping, multi-locus sequence typing (MLST) and capsular serotyping of hv-CRKP isolates were performed by PCR and Sanger sequencing. Results: A total of non-duplicate 264 CRKP clinical isolates were detected in the hospital from 2020 to 2022, and 23 hv-CRKP isolates were detected, so the corresponding detection rate of hv-CRKP was 8.71% (23/264). The hv-CRKP isolates in this study were mainly from the intensive care unit (10/23) and neurosurgery department (8/23), and the main sources of hv-CRKP isolates were sputum (10/23) and bronchoalveolar lavage fluid (6/23). The hv-CRKP isolates in this study were highly resistant to β-lactam antibiotics, fluoroquinolones and aminoglycosides, and were only susceptible to colistin, tigecycline and ceftazidime/avibactam. The detection rate of the blaKPC-2 among 23 hv-CRKP isolates was 91.30% (21/23) and none of the class B and class D carbapenemases were detected. Results of MLST and capsular serotypes showed that ST11 type hv-CRKP was the dominant strain in the hospital, accounting for 56.52% (13/23), and K64 (9/13) and KL47 (4/13) were the major capsular serotypes. Conclusion: The hv-CRKP isolates from the hospital are mainly from lower respiratory tract specimens from patients admitted to the intensive care department and the drug resistance is relatively severe. The predominant strains with certain polymorphisms are mainly composed of the KPC-2-producing ST11-K64 and ST11-KL47 hv-CRKP isolates in the hospital.
Humans ; Klebsiella pneumoniae/genetics* ; Multilocus Sequence Typing ; Retrospective Studies ; Klebsiella Infections/drug therapy* ; Anti-Bacterial Agents/therapeutic use* ; Hospitals ; Carbapenem-Resistant Enterobacteriaceae/genetics* ; Microbial Sensitivity Tests ; Carbapenems/pharmacology*

OBJECTIVETo investigate and take a case study on a Klebsiella pneumoniae outbreak in a newborn intensive care unit (NICU).

METHODSUsing epidemiological investigation method to cultivate bacilli and detect the homology.

RESULTSKlebsiella pneumonia was detected in 4 NICU patients. Based on environmental sample analyses, four Klebsiella pneumonia strains were identified and confirmed to be highly homologous. The outbreak was effectively controlled after the strict implementation of hand hygiene practice and environment disinfection.

CONCLUSIONKlebsiella pneumonia outbreak in NICU may be caused by the route of hand transmission.

Cross Infection ; epidemiology ; microbiology ; Disease Outbreaks ; Female ; Humans ; Infant, Newborn ; Intensive Care Units, Neonatal ; Klebsiella Infections ; epidemiology ; microbiology ; Klebsiella pneumoniae ; genetics ; isolation & purification ; Male

Five Klebsiella pneumonia strains (including two strains whose genes for lactic acid were knocked out) were used to produce 2,3-butanediol, in which K. pneumonia HR521 LDH (gene for lactic acid was knocked out) was the best for the production, and then the fermentation medium was optimized by orthogonal design. The optimum compositions were as follows: glucose 90 g/L, (NH4)2HPO4 3 g/L, CLSP 6 g/L, sodium acetate 5 g/L, KCl 0.4 g/L, MgSO4 0.1 g/L, FeSO4 x 7H2O 0.02 g/L, MnSO4 0.01 g/L. Under the above conditions, final concentration of acetone and 2,3-butanediol could reach 37.46 g/L, 10 g/L higher than that under the initial conditions, the yield was 90.53% of the theory, and the productivity was 1.5 g/(L-h), and no lactic acid was detected, which could be benefit for the downstream processing and industrial application.
Butylene Glycols ; metabolism ; Culture Media ; chemistry ; Fermentation ; Gene Knockout Techniques ; Glucose ; metabolism ; Klebsiella pneumoniae ; classification ; genetics ; growth & development ; metabolism

Objective The aim of our study is to investigate the prevalence of Carbapenem-resistant Klebsiella pneumoniae (CRKP) and the genetic characteristics of the class 1 integron in CRKP on multi-drug resistance.Methods Clinical Klebsiella pneumoniae strains were collected from multiple departments of a hospital in central China. CRKP strains were identified among the isolates, and antibiotics susceptibility of CRKP strains was analyzed. The polymerase chain reaction (PCR) was adopted to amplify the class 1 integron variable area. The integron genetic structure was analyzed with enzyme digestion and DNA sequencing technology. The relation between class 1 integron and drug resistance was analyzed statistically.Results Totally 955 strains of Klebsiella pneumoniae were isolated from varied sites of the hospital, and 117(12.3%) of them were identified as CRKP, with a separation rate of 8.9% (26/292) in 2013, 11.3% (38/336) in 2014 and 16.2% (53/327) in 2015, which shows an increasing trend by year. 44.4% (52/117) of CRKP strains were separated from specimen of ICU, and 61.5% (72/117) were from sputum. Over 95% CRKP strains were resistant to ampicillin/sulbactam, aztreonam, imipenem, meropenem, ceftazidme, cefotaxime, cefepime,and piperacillin, while relatively low resistant rates were found in tigecycline (12.8%) and colistin (35.9%). The class 1 integron was detected in 77.8% (91/117) of CRKP strains. Class 1 integron of CRKP was significantly correlated with the antibiotic resistance to the tobramycin, gentamicin and amikacin (all P<0.01). The gene cassette analysis of variable area of class 1 integron showed that aadA2 accounts for 64.8% (59/91), aacA4-catB8-aadA1 23.1% (21/91), and aadA2-dfrA25 12.1% (11/91).Conclusions CRKP has an increasing trend in a clinical setting in China, and most of them were resistant to multiple antibiotics. Class 1 integron in CRKP has strong ability to capture the genes resistant to aminoglycosides antibiotics from environment, with the aadA2 gene as the most popular one.
Anti-Bacterial Agents ; pharmacology ; Carbapenems ; pharmacology ; Drug Resistance, Bacterial ; Integrons ; Klebsiella pneumoniae ; drug effects ; genetics ; isolation & purification

1,3-propanediol production with the byproduct of biodiesel production is important to increase the economic benefit of biodiesel industry. Accumulation of 3-hydroxypropionaldehyde is one of the key problems in the 1,3-propanediol fermentation process, leading to the cell death and the fermentation abnormal ceasing. Different from the traditional way of reducing the accumulation of the 3-hydroxypropionaldehyde, we introduced the polyhydroxybutyrate pathway into the Klebsiella pneumoniae for the first time to enhance the tolerance of K. pneumoniae to 3-hydroxypropionaldehyde, at the same time, to improve the 1,3-propanediol production. Plasmid pDK containing phbC, phbA, phbB gene was constructed and transformed into K. pneumoniae successfully. PHB was detected in the engineered K. pneumoniae after IPTG induction and its content enhanced with the IPTG concentration increasing. The optimized IPTG concentration was 0.5 mmol/L. The constructed K. pneumoniae could produce 1,3-propanediol normally, at the same time accumulate polyhydroxybutyrate. With the constructed strain, the fermentation proceeds normally with the initial glucose was 70 g/L which the wild type strain stopped growing and the fermentation was ceasing; 1,3-propanediol concentration and yield reached 31.3 g/L and 43.9% at 72 h. Our work is helpful for the deep understanding of 1,3-propanediol metabolic mechanism of Klebsiella pneumoniae, and also provides a new way for strain optimization of Klebsiella pneumoniae.
Genetic Engineering ; methods ; Hydroxybutyrates ; metabolism ; Industrial Microbiology ; methods ; Klebsiella pneumoniae ; genetics ; metabolism ; Polymers ; metabolism ; Propylene Glycols ; metabolism

To investigate the carbapenemases distribution of carbapenem-resistant Klebsiella pneumoniae (CRKP) in the intensive care unit, and the clinical characteristics between carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) and carbapenem-resistant non-hypervirulent Klebsiella pneumoniae (CR-non-hvKP) were compared. A total of 53 non-repetitive CRKP strains isolated from 49 patients in the intensive care unit of the Second Affiliated Hospital of Xi'an Jiaotong University from May 2020 to March 2021 were retrospectively studied. The carbapenemase inhibitor enhancement test was used for screening carbapenemase-producing strains, and the string test was carried out to screen the hypermucoviscosity phenotype. Using PCR to detect five main carbapenemase genes (bla_KPC-2, bla_NDM, bla_IMP , bla_VIM and bla_OXA-48-like), common serotype (K1 and K2) and virulence gene (rmpA and iutA). Treated the strains with both rmpA and iutA genes as hypervirulent Klebsiella pneumonia (hvKP), and the whole genome sequencing of CR-hvKP was completed. At the same time, the clinical data of 49 patients were sorted out, and the differences in clinical characteristics of CR-hvKP and CR-non-hvKP infected patients were compared using the independent sample t test, Mann-Whitney U test, chi-square test or Fisher's exact probability test. CRKP isolated from the intensive care unit were extensively drug resistance and still had a good sensitivity to polymyxin B and tigecycline. Producing carbapenemases were the main resistance mechanism of CRKP (52/53, 98.1%). Of the 53 CRKP strains, except for 1strain that did not detect carbapenemase, at least one carbapenemase resistance gene was detected in the remaining 52 CRKP strains, of which 45 strains carried an enzyme, including 36 bla_KPC-2 (36/53, 67.9%), 8 bla_NDM (8/53, 15.1%), 1 bla_IMP (1/53, 1.9%), and 7 strains carried with both bla_KPC-2 and bla_NDM (7/53, 13.2%). String test and virulence gene showed that 7 CR-hvKP strains (13.2%) were detected in 53 CRKP strains, and two of which were hypermucoviscosity phenotype. Sequencing results revealed that CR-hvKP were mainly ST11 type. Almost all patients with CR-hvKP infection were over 60 years old (7/7), with invasive treatment (7/7), pulmonary infection with hypermucoviscosity phenotype (2/7) and high mortality (5/7); and the percentage of neutrophils in patients with CR-hvKP infection (86.44±4.70) % was higher than those patients with CR-non-hvKP infection (78.90±19.15) %, the difference was statistically significant (t=-2.225, P=0.032). The CR-hvKP strains in the intensive care unit mainly produced KPC-2 enzyme, with K2 capsular serotype and ST11 type. It is necessary to strengthen the monitoring and control of the CR-hvKP strain to prevent the co-evolution of drug-resistant and hypervirulent strains.
Anti-Bacterial Agents/therapeutic use* ; Carbapenems/pharmacology* ; Humans ; Intensive Care Units ; Klebsiella pneumoniae/genetics* ; Middle Aged ; Retrospective Studies