Carbapenems ; pharmacology ; Drug Resistance, Bacterial ; Humans ; Klebsiella Infections ; drug therapy ; microbiology ; Klebsiella pneumoniae ; drug effects

OBJECTIVE: To explore the clinical characteristics of hospitalized patients with hematologic diseases complicated with carbapenem-resistant organisms (CRO) infection and analyze the risk factors of 30-day all-cause mortality. METHODS: The clinical data and laboratory test data of 77 hospitalized patients with hematologic diseases complicated with CRO infection in department of hematology of the Third Hospital of Shanxi Medical University from January 2015 to December 2020 were retrospectively analysed, the risk factors of 30-day all-cause mortality after CRO infection were analyzed by multivariate logistic regression. RESULTS: Among the total of 77 patients with hematologic diseases complicated with CRO infection, 29 died and 48 survived within 30 days of infection, with a case fatality rate of 37.66%. A total of 93 strains of CRO were isolated from these patients, of which Acinetobacter baumannii had the highest detection rate (25.81%, 24/93), followed by Pseudomonas aeruginosa (18.28%, 17/93). The lung was the most common site of CRO infection. The detected pathogens were highly resistant to carbapenems, and 64.52% (60/93) of the pathogens were resistant to imipenem with minimum inhibitory concentration (MIC)≥16 μg/ml. The results of the univariate analysis showed that albumin concentration <25 g/L (P =0.048), serum creatinine concentration≥120 μmol/L (P =0.023), age-adjusted Charlson comorbidity index (ACCI) (P =0.037) and primary treatments (supportive treatment, immunosuppressive therapy, chemotherapy, HSCT) (P =0.048) were significantly associated with 30-day all-cause mortality after infection. The results of multivariate logistic regression analysis showed that when CRO infection confirmed, albumin concentration <25 g/L (P =0.014, OR=6.171), serum creatinine concentration≥120 μmol/L (P =0.009, OR=10.867) were independent risk factors for 30-day mortality of patients with hematologic diseases complicated with CRO infection. CONCLUSION The mortality rate of CRO-infected patients with hematologic diseases is high. The detected pathogenic bacteria are highly resistant to imipenem. The albumin concentration <25 g/L and the serum creatinine concentration≥ 120 μmol/L at diagnosis of CRO infection were independent risk factors for 30-day mortality of the patients with hematologic diseases.
Humans ; Carbapenems/pharmacology* ; Retrospective Studies ; Creatinine ; Hematologic Diseases ; Risk Factors ; Imipenem ; Albumins

Acinetobacter baumannii ; drug effects ; Anti-Bacterial Agents ; pharmacology ; Carbapenems ; pharmacology ; Drug Resistance, Bacterial ; Microbial Sensitivity Tests ; Minocycline ; analogs & derivatives ; pharmacology

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

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

OBJECTIVES: To systematically assess the risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children. METHODS: PubMed, Web of Science, China National Knowledge Infrastructure Database, Wanfang Data, China Biology Medicine disc were searched to obtain the articles on risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children published up to May 31, 2021. RevMan 5.3 software was used to perform the Meta analysis. RESULTS: A total of 13 articles were included, with 1 501 samples in total. The Meta analysis showed that indwelling gastric tube (OR=4.91), tracheal intubation (OR=5.03), central venous catheterization (OR=3.75), indwelling urinary catheterization (OR=4.11), mechanical ventilation (OR=3.09), history of hospitalization in the intensive care unit (OR=2.39), history of surgical operation (OR=3.22), previous use of third-generation cephalosporins (OR=2.62), previous use of carbapenem antibiotics (OR=3.82), previous use of glycopeptide antibiotics (OR=3.48), previous use of β-lactamase inhibitors (OR=2.87), previous use of antifungal drugs (OR=2.48), previous use of aminoglycoside antibiotics (OR=2.54), and Apgar score ≤7 at 1 minute after birth (OR=2.10) were risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children (P<0.05). CONCLUSIONS Invasive operations, history of hospitalization in the intensive care unit, previous use of antibiotics such as carbapenem antibiotics, and Apgar score ≤7 at 1 minute after birth are risk factors for the colonization or infection of carbapenem-resistant Enterobacteriaceae in children.
Anti-Bacterial Agents/therapeutic use* ; Carbapenem-Resistant Enterobacteriaceae ; Carbapenems/pharmacology* ; Child ; Enterobacteriaceae Infections/microbiology* ; Humans ; Risk Factors

OBJECTIVETo study the resistance mechanism and homology of carbapenems-resistant Pseudomonas aeruginosa (PA).

METHODSA total of 812 strains of PA (identified) were isolated from sputum, urine, blood, pus, and drainage of patients with burn, severe pneumonia, diabetes, chronic obstructive pneumonia, myocarditis, liver transplantation, or brainstem hemorrhage hospitalized from January to September 2012. Drug resistance of the 812 strains of PA to 15 antibiotics commonly used in clinic, including piperacillin, imipenem, etc., was tested using the automatic microorganism identifying and drug sensitivity analyzer. Among the carbapenems-resistant PA isolates, synergism test with imipenem-ethylene diamine tetraacetic acid (EDTA) and enhancement test with imipenem-EDTA and ceftazidime-EDTA were used to screen metallo-β-lactamase (MBL)-producing strains; modified Hodge test was used to screen strains producing Klebsiella pneumoniae carbapenemases (KPC); the carbapenemase gene, plasmid mediated quinolone resistant (PMQR) gene, and mobile genetic elements (MGE) were detected by polymerase chain reaction (PCR). In addition, a comparative analysis of the PMQR gene carrying level between the carbapenemase gene positive strains and carbapenemase gene negative strains was carried out. The repetitive consensus sequence of Enterobacteriaceae genome PCR (ERIC-PCR) was carried out for gene typing. Moreover, the source and resistance genes of strains with the same genotype were analyzed. Data were processed with Fisher's exact probability test.

RESULTSThe sensitive rates of the 812 strains of PA to ceftriaxone and trimethoprim-sulfamethoxazole were high, respectively 83.07% and 88.19%, and those of the other antibiotics ranged from 17.30% to 55.18%. Twenty-four carbapenems-resistant PA strains were screened, including 11 MBL-producing strains and 2 KPC-producing strains. Eleven carbapenems-resistant PA strains were found to harbor the blaVIM-2 gene, accounting for 45.83%; 2 carbapenems-resistant PA strains carried the blaKPC-2 gene, accounting for 8.33%. Fourteen carbapenems-resistant PA strains only harbored the PMQR gene acc (6')-Ib-cr, accounting for 58.33%; 3 carbapenems-resistant PA strains (12.50%) harbored the PMQR genes acc (6')-Ib-cr and qnr, including 1 strain with qnr A1 and 2 strains with qnr B4. Ten carbapenems-resistant PA strains carried the MGE gene ISCR1, accounting for 41.67%; 6 carbapenems-resistant PA strains carried the MGE gene ISEcp1, accounting for 25.00%. In addition, 3 carbapenems-resistant PA strains co-harbored the MGE genes ISCR1 and ISEcp1 (accounting for 12.50%), while only 1 carbapenems-resistant PA strain co-harbored the MGE genes class 1 integron and ISEcp1, accounting for 4.17%. Twelve out of the 13 carbapenemase gene positive strains carried one or two PMQR gene (s), which was significantly higher than that of the carbapenemase gene negative strains (with only five strains harboring one PMQR gene, P = 0.023). The 24 carbapenems-resistant PA strains were classified into 6 genotypes by the ERIC-PCR. Thirteen strains (accounting for 54.17%), mainly isolated from pus and blood samples, which were collected from burn department, were in genotype A. Eight out of the 13 strains harbored genes blaVIM-2, acc (6')-Ib-cr, and ISCR1. Five strains (accounting for 20.83%), mainly isolated from sputum samples which were collected from ICU, were in genotype B. Only 2 out of the 5 strains co-harbored the carbapenemase gene, PMQR gene, and MGE gene. There were respectively 2 strains in genotypes C and D, both accounting for 8.33%; the strains in different pattern were isolated from different wards, and they harbored diverse resistance genes. There were respectively 1 strain in genotypes E and F, both accounting for 4.17%.

CONCLUSIONSThe resistance mechanism of PA to carbapenems is mainly mediated by the VIM-2 type MBL in our hospital during 2012, followed by KPC-2 type carbapenemase, and the prevalent genotype is type A. The carbapenemase genes and PMQR genes co-carrying phenomenon exists among these strains of PA, which disseminated by clones.

Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Carbapenems ; pharmacology ; DNA, Bacterial ; Drug Resistance, Bacterial ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; drug effects ; genetics ; isolation & purification ; beta-Lactamases ; genetics

OBJECTIVETo study the resistance phenotype and homology of Klebsiella pneumoniae (KPN) in burn patients with infection.

METHODSFifty-four strains of KPN were isolated from wound excretion, blood, sputum, venous catheter, feces, and oral cavity of patients hospitalized in Institute of Burn Research of Southwest Hospital (briefly called our institute) from January 2007 to June 2011. Drug resistance of the 54 strains of KPN to 18 antibiotics commonly used in clinic, including ampicillin, ticarcillin, etc, was tested by K-B paper disk diffusion method after being identified. Extended-spectrum β-lactamase (ESBL)-producing KPN was screened based on the drug resistance result. The positive rates of drug-resistant genes SHV, TEM, and CTX-M of the ESBL-producing KPN were detected by polymerase chain reaction. The homology of the ESBL-producing KPN was analyzed by pulse field gel electrophoresis and clustering methodology. The homology of ESBL-producing KPN isolated in each year was analyzed too.

RESULTS(1) The sensitive rate of the 54 strains of KPN to imipenem, meropenem, and ertapenem was respectively 96.30%, 92.59%, and 81.48%, that of these strains to cefotetan and cefoxitin was respectively 70.37% and 64.81%, and that of these strains to ceftazidime was 57.41%. The sensitive rates of the 54 strains of KPN to the other antibiotics were all lower than 40.00%. (2) Twenty-six ESBL-producing KPN strains were screened and the positive rate of SHV, TEM, and CTX-M was 96.15% (25/26), 76.92% (20/26), and 57.69% (15/26), respectively. Detection rate of ESBL-producing KPN strains carrying three genes at the same time was 42.31% (11/26), that of these strains carrying both SHV and TEM was 34.62% (9/26), and those of these strains carrying only a single gene were all less than 10.00%. (3) The twenty-six ESBL-producing KPN were classified into 9 gene types, with 30.77% (8/26) in type A, 19.23% (5/26) in type B, 15.38% (4/26) in type C, 11.54% (3/26) in type D, 7.69% (2/26) in type E, and the rest four strains respectively in type F, G, H, I [3.85% (1/26)]. (4) The major gene type of ESBL-producing KPN in the year of 2007 and 2010 was type A, respectively accounting for 2/3 and 1/2, while that in the year of 2009 was type B, accounting for 1/2. The three strains in 2008 was respectively in type C, E, and F. The four strains in 2011 was respectively in type A, D, H, I.

CONCLUSIONSKPN in burn patients with infection in our institute are highly resistant to commonly used antibiotics in clinic, but carbapenems antibiotics can be used for the treatment. Most of the ESBL-producing KPN strains carry two or three drug-resistant genes, and the main gene type of them is type A.

Anti-Bacterial Agents ; pharmacology ; Burns ; microbiology ; Carbapenems ; pharmacology ; DNA, Bacterial ; analysis ; Drug Resistance, Bacterial ; genetics ; Genes, Bacterial ; Humans ; Klebsiella pneumoniae ; genetics ; isolation & purification ; Microbial Sensitivity Tests ; Sequence Homology

BACKGROUND: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) and Acinetobacter baumannii (CRAB) are the leading causes of nosocomial infections. A rapid and sensitive test to detect CRPA and CRAB is required for appropriate antibiotic treatment. We optimized a loop-mediated isothermal amplification (LAMP) assay to detect the presence of bla(VIM-2), bla(IMP-1), and bla OXA-23, which are critical components for carbapenem resistance. METHODS: Two sets of primers, inner and outer primers, were manually designed as previously described. The LAMP buffer was optimized (at 2mM MgSO4) by testing different concentrations of MgSO4. The optimal reaction temperature and incubation time were determined by using a gradient thermocycler. Then, the optimized bla(VIM-2), bla(IMP-1), and bla(OXA-23) LAMP reactions were evaluated by using 120 P. aeruginosa and 99 A. baumannii clinical isolates. RESULTS: Only one strain of the 100 CRPA isolates harbored bla(IMP-1), whereas none of them harbored bla(VIM-2). These results indicate that the acquisition of bla(VIM-2) or bla(IMP-1) may not play a major role in carbapenem resistance in Korea. Fifty two strains of the 75 CRAB isolates contained bla(OXA-23), but none contained bla(VIM-2) and bla(IMP-1) alleles. CONCLUSIONS: Our results demonstrate the usefulness of LAMP for the diagnosis of CRPA and CRAB.
Acinetobacter baumannii/genetics/*isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Carbapenems/*pharmacology ; Drug Resistance, Bacterial/*genetics ; *Genes, Bacterial ; Nucleic Acid Amplification Techniques ; Pseudomonas aeruginosa/genetics/*isolation & purification ; Sensitivity and Specificity

To explore the clinical distribution and drug resistance characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP), in order to provide reference for the prevention and treatment of CRKP infection. Retrospective analysis was performed on 510 clinical isolates of CRKP from January 2017 to December 2021, and strain identification and drug sensitivity tests were conducted by MALDI-TOF mass spectrometer and VITEK-2 Compact microbial drug sensitivity analyzer. The carbapenemase phenotype of CRKP strain was detected by carbapenemase inhibitor enhancement test. The CRKP strain was further categorized by immunochromogenic method and polymerase chain reaction (PCR) was used for gene detection. The results showed that 302 strains (59.2%) were derived from sputum, 127 strains (24.9%) from urine and 47 strains (9.2%) from blood. 231 (45.3%) were mainly distributed in intensive care, followed by 108 (21.2%) in respiratory medicine and 79 (15.5%) in neurosurgery. Drug susceptibility test result shows that the resistant rate of tigecycline increased from 1.0% in 2017 to 10.1% in 2021, the difference was statistically significant (χ²=14.444,P<0.05). The results of carbapenemase inhibitor enhancement test showed that 461 carbapenemase strains (90.4%) of 510 CRKP strains, including 450 serinase strains (88.2%), 9 metalloenzyme strains (1.8%), and 2 strains (0.4%) produced both serine and metalloenzyme. 49 strains (9.6%) did not produce enzymes. Further typing by immunochromogenic assay showed that 461 CRKP strains were KPC 450 (97.6%) and IMP 2 (0.4%). 7 NDM (1.5%); 2 strains of KPC+NDM (0.4%); PCR results were as follows: 450 strains of blaKPC (97.6%), 2 strains of blaIMP (0.4%), 7 strains of blaNDM (1.5%), and 2 strains of blaKPC+NDM (0.4%). In conclusion, CRKP strains mainly originated from sputum specimens and distributed in intensive care department, and the drug resistance characteristics were mainly KPC type in carbapenemase production. Clinical microbiology laboratory should strengthen the monitoring of CRKP strains, so as to provide reference for preventing CRKP infection and reducing the production of bacterial drug resistance.
Anti-Bacterial Agents/pharmacology* ; Carbapenems/pharmacology* ; Klebsiella pneumoniae/genetics* ; Hospital Distribution Systems ; Retrospective Studies ; Microbial Sensitivity Tests ; beta-Lactamases/genetics* ; Bacterial Proteins/genetics* ; Drug Resistance, Bacterial/genetics*