Molecular epidemiology of clinical isolation of carbapenem-resistant Enterobacterales and application of carbapenemase inhibitor enhancement test. / ä¸´åºŠåˆ†ç¦»ç¢³é’éœ‰çƒ¯ç±»è€è¯è‚ æ†èŒç›®ç»†èŒèŒæ ªçš„åˆ†å­æµè¡Œç— å­¦åŠç¢³é’éœ‰çƒ¯é ¶æŠ‘åˆ¶å‰‚å¢žå¼ºè¯•éªŒçš„åº”ç”¨.

OBJECTIVES: The prevalence of carbapenem-resistant Enterobacterales (CRE) presents a significant challenge in clinical anti-infective treatment. This study aims to investigate drug resistance and the molecular epidemiological characteristics of CRE in our area. Additionally, we seek to evaluate practicality of utilizing carbapenemase inhibitor enhancement test in clinical laboratory. METHODS: Non-repeated CREs isolated from clinical specimens at Xiangya Hospital, Central South University, were collected. Minimum inhibitory concentration (MIC) combined with Kirby-Bauer (KB) assay was used to detect the drug susceptibility of the strains, and 13 carbapenemase-producing genes were detected by PCR. The phenotype of 126 strains of carbapenemase-producing Enterobacterales identified by PCR was detected by the carbapenemase inhibitor enhancement test to understand the agreement between the method and the gold standard PCR results. RESULTS: Among 704 CRE strains examined, we observed significant drug resistance in 501 strains dentified as carbapenemase-producing Enterobacterales (CPE). Klebsiella pneumoniae was the predominant CPE strain, followed by Enterobacter cloacae and Escherichia coli. A total of 9 carbapenemase types were detected, including Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-ß-lactamase (NDM), Verona integron- encoded metallo-ß-lactamases (VIM), imipenemase (IMP), oxacillinase-48 (OXA-48), and rare imipenem-hydrolyzing ß-lactamase (IMI), adelaide imipenemase (AIM), Bicêtre carbapenemase (BIC), and guiana extended-spectrum ß-lactamase (GES). The detection rate of KPC serine carbapenemase was 61.7% (309/501). The carbapenemase inhibitor enhancement test exhibited a 100% consistency rate for the strains producing Class A serine carbapenemase and/or Class B metallo-ß-lactamases. CONCLUSIONS: CRE strains in Changsha, Hunan, China, are wide distribution and exhibit carbapenemase production. The main mechanism of carbapenem resistance in these bacterias is predominatly attributed to the production of KPC serine carbapenemase. The presence of GES and IMI genes carried by Enterobacterales has been detected for the first time in this region. The carbapenemase inhibitor enhancement test has been proven to be an accurate method for detecting CRE producing Class A serine carbapenemase and/or Class B metallo-ß-lactamases. This method offers simpicity of operation and ease of results interpretation, making it weel-suited meeting the clinical microbiology laboratory's reguirements for the detection of serine carbapenemase and metallo-ß-lactamases.

Clinical value of lymphocyte count in autoimmune diabetic nephropathy. / æ·‹å·´ç»†èƒžè®¡æ•°åœ¨è‡ªèº«å ç–«æ€§ç³–å°¿ç— è‚¾ç— ä¸­çš„ä¸´åºŠä»·å€¼ï¼ˆè‹±æ–‡ï¼‰.

OBJECTIVES: In recent years, the prevalence of diabetic nephropathy (DN) has increased significantly. An increasing number of studies have shown that lymphocyte-associated inflammatory responses play a role in DN. This study aims to investigate the relationship between lymphocytes and DN in patients with autoimmune diabetes. METHODS: The clinical data of 226 patients with Type 1 diabetes (T1D) and 79 patients with latent autoimmune diabetes in adults (LADA) were retrospectively studied and stratified according to the urinary albumin to creatinine ratio (ACR). Risk factors associated with DN were analyzed using correlation analysis and logistic regression. RESULTS: In T1D and LADA patients, systolic blood pressure (SBP), uric acid duration, and diabetes duration in patients with normoalbuminuria were lower or shorter than those in patients with macroalbuminuria (P<0.05). The lymphocyte count of T1D patients was significantly higher than that in LADA patients (P<0.05), while the neutrophil to lymphocyte ratio (NLR) of T1D patients was significantly lower than that in LADA patients (P<0.05). The lymphocyte count in the T1D patients with normoalbuminuria was lower than that those with macroalbuminuria (P<0.05). The NLR was lower in the T1D patients with macroalbuminuria than those with microalbuminuria and normoproteinuria (all P<0.01). Based on logistic regression analysis, lymphocytes were independently associated with DN in T1D after adjusting for various known risk factors such as course of disease, age, gender, dyslipidemia, hypertension, and smoking status. Analysis of the receiver operating characteristic curve of subjects predicting lymphocytes in normoalbuminuria showed that the area under the curve was 0.601 (95% CI 0.510 to 0.693, P=0.039), and when the cutoff value of lymphocytes was 2.332, the sensitivity was 37.0%, and the specificity was 82.5%. CONCLUSIONS: Lymphocyte counts in autoimmune diabetic patients are closely associated with DN, suggesting that lymphocyte-mediated inflammation may be involved in the pathogenesis of DN in autoimmune diabetic patients. This study provides a possible perspective for using lymphocytes as a potential biomarker for the early identification of individuals at risk for DN and potential therapeutic targets for DN.

Molecular epidemiology and clinical characteristics of Clostridioides difficile infection in patients with inflammatory bowel disease from a teaching hospital.

BACKGROUND: Clostridioides difficile infection (CDI) in patients with inflammatory bowel disease (IBD) is of increasing concern. This study aimed to investigate the molecular epidemiology and antimicrobial susceptibilities of toxigenic C. difficile isolated from IBD patients and to evaluate the risk factors for CDI in IBD population. METHODS: Loose or watery stools from IBD patients were tested for glutamate dehydrogenase, C. difficile toxins A&B and anaerobic culture. Toxigenic C. difficile isolates were characterized by multi-locus sequence typing, ribotyping and antimicrobial susceptibility testing. RESULTS: The prevalence of CDI in IBD patients was 13.6% (43/317). The dominant sequence types (STs) were ST35 (20.9%), ST2 (18.6%) and ST37 (16.3%). The most common ribotypes (RTs) were RT 017 (18.6%), RT 012 (14.0%), and RT 220 (14.0%), whereas RT 027 and RT 078 were not detected in this study. All the isolates were susceptible to vancomycin and metronidazole. The multidrug resistance rate of C. difficile RT 017 was higher (p < 0.01) than that of other RT strains. Recent hospitalization, use of corticosteroids and proton pump inhibitors were related to increased risk of CDI in IBD patients; of these, recent hospitalization and proton pump inhibitors use were independent risk factors. CONCLUSION: Patients with IBD have a relatively high incidence rate of CDI. C. difficile RT 017 is most frequently isolated from IBD patients in this region and warrants more attention to its high resistance rate. Clinicians should pay greater attention to CDI testing in IBD patients with diarrhea to ensure early diagnosis and initiation of effective treatment.

A retrospective study on Escherichia coli bacteremia in immunocompromised patients: Microbiological features, clinical characteristics, and risk factors for shock and death.

BACKGROUND: To evaluate clinical features, bacterial characteristics, and risk factors for shock and mortality of immunocompromised patients with Escherichia coli bacteremia. METHODS: A nearly 6-year retrospective study of E coli bacteremia in 188 immunocompromised patients at Xiangya Hospital was conducted. Demographic, clinical, and laboratory data were documented. Phylogenetic background and virulence factors of E coli isolates were detected by polymerase chain reaction. Risk factors for shock and mortality were also investigated. RESULTS: Of all 188 E coli isolates, most prevalent virulence factors were fimH (91.0%), followed by traT (68.6%) and iutA (67.0%), while papG allele I, gafD, and cdtB were not detected. Phylogenetic group D was dominant (42.0%) among all isolates, and group B2 accounted for 17.6%, while group A and B1 accounted for 28.2% and 12.2%, respectively. In univariate analysis, ibeA and cnf1 were associated with mortality, which were not found in multivariate regression analysis. 22.3% of patients suffered shock, and 30-day mortality rate was 21.3%. MDR (HR 2.956; 95% CI, 1.091-8.012) was the only risk factor for shock, while adult (HR 0.239; 95% CI, 0.108-0.527) was a protective factor. Multivariate analysis revealed that shock (HR 4.268; 95% CI, 2.208-8.248; P < .001) and Charlson index > 2 (HR 2.073; 95% CI, 1.087-3.952; P = .027) were associated with fatal outcome. CONCLUSIONS: Escherichia coli bacteremia was highly lethal in immunocompromised patients, and host-related factors played major roles in poor prognosis, while bacterial determinants had little effect on outcome. This study also provided additional information about the virulence and phylogenetic group characteristics of E coli bacteremia.

[AdeABC efflux pump and resistance of Acinetobacter baumannii against carbapenem].

OBJECTIVE: To investigate relationship between AdeABC efflux pump and resistance of Acinetobacter baumannii against carbapenem.
 Methods: Carbapenem-resistant strains were acquired from multistep selection resistance test by meropenem in vitro. The quantitation test for sensitivities of strains before and after induction was determined by the E-test, and carbonylcyanide-m-chlorophenylhydrazone (CCCP) inhibition test was used to screen efflux pump. PCR, sequencing analysis, or real-time PCR was used to analyze the changes of regulatory genes adeR and adeS of the AdeABC efflux pump system, or expressions of adeA, adeB, adeR, and adeS in the strains before and after induction, respectively.
 Results: The minimal inhibitory concentrations (MICs) of meropenem were at 0.38 µg/mL and 0.25 µg/mL in parental sensitive strain S25595 and S7257, respectively, and the MICs of meropenem for both S25595 and S7257 after induction were more than 32 µg/mL. Compared with parental sensitive strains, the expression level of adeA, adeB, adeR, and adeS mRNA were elevated from 2.45 to 9.44 times, but there were no gene mutations or insertion sequences in the regulatory gene adeS and adeR.
 Conclusion: High expression of the AdeABC efflux pump system in Acinetobacter baumannii is closely associated with meropenem resistance. The upregulation of adeA and adeB expression is not due to gene mutations in the regulatory gene adeS and adeR and other mechanisms might account for it.

Characterization of clinical extensively drug-resistant Pseudomonas aeruginosa in the Hunan province of China.

BACKGROUND: Pseudomonas aeruginosa strains that are classed as extensively drug resistant (XDR-PA) are resistant to all antibiotics except for one or two classes and are frequently the cause of hard-to-treat infections worldwide. Our study aimed to characterize clinical XDR-PA isolates recovered during 2011-2012 at nine hospitals in the Hunan province of China. METHODS: Thirty-seven non-repetitive XDR-PA strains from 37 patients were investigated for genes encoding antimicrobial resistance determinants, efflux pumps, outer membrane proteins, and movable genetic elements using polymerase chain reaction (PCR). The expression of genes encoding the efflux pump component MexA and the outer membrane protein OprD was measured using real-time PCR. In addition, clonal relatedness of these XDR-PA isolates was analyzed by pulsed-field gel electrophoresis (PFGE). RESULTS: Various genes encoding antimicrobial resistance determinants were found in all isolates. In particular, the bla TEM-1, bla CARB, armA, bla IMP-4, bla VIM-2, and rmtB, were found in 100, 37.8, 22, 22, 19 and 5 % of the isolates, respectively. Remarkably, two isolates coharbored bla IMP-4, bla VIM-2, and armA. In all 37 antibiotic-resistant strains, the relative expression of oprD was decreased while mexA was increased compared to the expression of these genes in antibiotic-susceptible P. aeruginosa strains. All of the XDR-PA isolates harbored class I integrons as well as multiple other mobile genetic elements, such as tnpU, tnp513, tnpA (Tn21), and merA. A high genotypic diversity among the strains was detected by PFGE. CONCLUSIONS: Multiple antibiotic-resistance mechanisms contributed to the drug resistance of the XDR-PA isolates investigated in this study. Thus, the XDR-PA isolates in this area were not clonally related. Instead, multiple types of movable genetic elements were coharbored within each XDR-PA isolate, which may have aided the rapid development of these XDR-PA strains. This is the first report of XDR-PA strains that coharbor bla IMP-4, bla VIM-2, and armA.

Emergence and spread of O16-ST131 and O25b-ST131 clones among faecal CTX-M-producing Escherichia coli in healthy individuals in Hunan Province, China.

OBJECTIVES: The objectives of this study were to determine CTX-M-producing Escherichia coli ST131 strain prevalence in stool specimens from healthy subjects in central China and to molecularly characterize clonal groups. METHODS: From November 2013 to January 2014, stool specimens from healthy individuals in Hunan Province were screened for ESBL-producing E. coli using chromogenic medium and CTX-M genotypes and phylogenetic groups were determined. ST131 clonal groups were detected by PCR and characterized for antibiotic resistance, fimH, gyrA and parC alleles, plasmid-mediated quinolone resistance determinants, virulence genotypes and PFGE patterns. RESULTS: Among 563 subjects, 287 (51.0%) exhibited the presence of faecal ESBL-producing E. coli, all of which produced CTX-M enzymes. The most common CTX-M genotypes were CTX-M-14 (48.4%), CTX-M-15 (27.5%) and CTX-M-27 (15.0%). Of the 287 CTX-M-producing isolates, 32 (11.1%) belonged to the ST131 clone. O16-ST131 isolates were dominant (75%) and contained the fimH41 allele. The remaining eight (25%) ST131 isolates were of the O25b subgroup and contained fimH30 or fimH41. Ciprofloxacin resistance was found in 100% of the O25b-ST131 isolates, whereas only 8% of the O16-ST131 isolates were resistant. All of the O25b-ST131 isolates except one showed gyrA1AB and parC1aAB mutations; most of the O16-ST131 isolates had gyrA1A and parC1b mutations. The virulence genotypes of O16-ST131 resembled those of the O25b-ST131 isolates. The 32 ST131 isolates formed one large group at the 64% similarity level. They comprised 15 PFGE groups (defined at ≥85% similarity). CONCLUSIONS: O16-ST131 isolates have emerged as the predominant type of ST131 isolate in faecal CTX-M-producing E. coli in healthy individuals in China.

Promoter methylation-mediated downregulation of PRDM5 contributes to the development of lung squamous cell carcinoma.

PRDM5 has been proposed as a tumor suppressor frequently downregualted in tumor. In this study, lung squamous cell carcinoma tissues and adjacent nontumorous normal tissues were collected from 30 patients. PRDM5 expression was detected by reverse transcription polymerase chain reaction and Western blot analysis, DNA methylation of PRDM5 promoter was analyzed by methylation-specific PCR. SK-MES-1 cells or xenografts in nude mice were treated with 5-aza-2'-deoxycitydine, and cell proliferation and tumor growth in nude mice were examined. We found that PRDM5 promoter was methylated and PRDM5 expression at both mRNA and protein levels was reduced in lung squamous cell carcinoma tissues. Furthermore, PRDM5 promoter methylation was significantly correlated with tumor differentiation and lymph node metastasis of lung squamous cell carcinoma, but not with age, gender, smoking, or tumor grade. 5-aza-2'-deoxycitydine inhibited the proliferation of SK-MES-1 cells and the growth of xenografts in nude mice, accompanied by reduced methylation of PRDM5 promoter and increased expression of PRDM5. Taken together, our data suggest that PRDM5 is a tumor suppressor in lung cancer and is a promising target for the diagnosis, prognosis, and therapy of lung squamous cell carcinoma.

Molecular epidemiology of Clostridium difficile infection in a major chinese hospital: an underrecognized problem in Asia?

Clostridium difficile infection is almost unrecognized in mainland China. We have undertaken a study in a large Chinese teaching hospital in Changsha, Hunan, China, to identify cases of C. difficile, record patient characteristics, and define the molecular epidemiology with respect to ribotype distribution and cross-infection. Between April 2009 and February 2010, we examined fecal samples from 70 hospitalized patients with diarrhea who were receiving or had received antibiotics within the previous 6 weeks. Clinical information was collected and the samples were cultured for C. difficile retrospectively. Isolates were ribotyped, and multiple-locus variable-number tandem-repeat assay (MLVA) subtyping was performed on clusters of the same ribotype. The mean age of patients from whom C. difficile was cultured was 58 years, with only 4/21 patients aged >65 years. All patients, with a single exception, had received a third-generation cephalosporin and/or a quinolone antibiotic. Twenty-one isolates of C. difficile were recovered, and seven different ribotypes were identified, the dominant types being 017 (48%), 046 (14%), and 012 (14%). We identified two clusters of cross-infection with indistinguishable isolates of ribotype 017, with evidence of spread both within and between wards. We have identified C. difficile as a possibly significant problem, with cross-infection and a distinct ribotype distribution, in a large Chinese hospital. C. difficile may be underrecognized in China, and further epidemiological studies across the country together with the introduction of routine diagnostic testing are needed to ascertain the size of this potentially significant problem.

Novel species including Mycobacterium fukienense sp. is found from tuberculosis patients in Fujian Province, China, using phylogenetic analysis of Mycobacterium chelonae/abscessus complex.

OBJECTIVE: To identify the novel species 'Mycobacterium fukienense' sp. nov of Mycobacterium chelonae/abscessus complex from tuberculosis patients in Fujian Province, China. METHODS: Five of 27 clinical Mycobacterium isolates (Cls) were previously identified as M. chelonae/abscessus complex by sequencing the hsp65, rpoB, 16S-23S rRNA internal transcribed spacer region (its), recA and sodA house-keeping genes commonly used to describe the molecular characteristics of Mycobacterium. Clinical Mycobacterium isolates were classified according to the gene sequence using a clustering analysis program. Sequence similarity within clusters and diversity between clusters were analyzed. RESULTS: The 5 isolates were identified with distinct sequences exhibiting 99.8% homology in the hsp65 gene. However, a complete lack of homology was observed among the sequences of the rpoB, 16S-23S rRNA internal transcribed spacer region (its), sodA, and recA genes as compared with the M. abscessus. Furthermore, no match for rpoB, sodA, and recA genes was identified among the published sequences. CONCLUSION: The novel species, Mycobacterium fukienense, is identified from tuberculosis patients in Fujian Province, China, which does not belong to any existing subspecies of M. chelonea/abscessus complex.

[An analysis of resistance of nosocomial infection pathogens isolated from 13 teaching hospitals in 2011].

OBJECTIVE: To investigate the pathogen profile of nosocomial infection in China, and to survey the susceptibility rates of these pathogens to the clinical common antibiotics. METHODS: The non-repetitive nosocomial pathogens isolated from bloodstream infection (BSI), hospital acquired pneumonia (HAP) and intra-abdominal infection (IAI) and the case data were collected from 13 teaching hospitals in different areas of China and sent to a central laboratory for re-identification and susceptibility testing. The levels of minimal inhibitory concentration (MIC) of the common antibiotics were determined by agar dilution method. The data were analyzed by WHONET 5.6 software. RESULTS: A total of 2103 clinical isolates were collected from January to December 2011, of which gram positive cocci and gram negative organisms accounted for 23.2% and 76.8% respectively. The top three pathogens of BSI were E. coli (31.0%, 243/784), K. pneumoniae (14.8%, 116/784) and S. aureus (10.6%, 83/784). The top three pathogens of HAP were A. baumannii (24.2%, 158/652), P. aeruginosa (23.0%, 150/652) and K. pneumoniae (16.4%, 107/652). The top three pathogens of IAI were E. coli (34.3%, 229/667), E. faecium (13.3%, 89/667) and K. pneumoniae (9.6%, 64/667). Methicillin-resistant S. aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) accounted for 64.4% and 78.1% respectively. The susceptibility rates of Staphylococcus species to tigecycline, vancomycin, teicoplanin and linezolid were all 100%. The prevalence of MRSA in HAP was significantly higher than that in BSI or IAI. The susceptibility rates of Enterococcus species to tigecycline, teicoplanin and linezolid were all 100%. The prevalence of extended-spectrum ß-lactamases (ESBL) was 64.3% in E. coli and 38.3% in K. pneumonia. Against Enterobacteriaceae, the most active agents were as following in order: tigecycline (92.3% - 100%) [except P.mirabilis], meropenem (87.5% - 100%), imipenem (87.5% - 100%) [except M. morganii], amikacin (87.5% - 100%), polymyxin B (75% - 100%) [except S. marcescens, P. mirabilis and M morganii], cefepime (67.8% - 100%), cefoperazone-sulbactam (66.6% - 100%), piperacillin-tazobactam (61.5% - 100%). Carbapenem-resistance Enterobacteriaceae strains emerged. The susceptibility rates of P. aeruginosa to imipenem and meropenem were 66.2% and 72.2%, respectively. The susceptibility rates of A. baumannii to imipenem and meropenem were 27.7% and 25.9%, respectively. The most active agents against A. baumannii were polymyxin B (100%), followed by tigecycline (79.8%) and minocycline (50.4%). The susceptibility rates of P.aeruginosa to antibiotics in BSI were higher than those in HAP and IAI. Susceptibility rates of S. maltophilia to trimethoprim-sulfamethoxazole, minocycline and levofloxacin were about 90% or above. Susceptibility rates of B. cepacia to trimethoprim-sulfamethoxazole, ceftazidime and meropenem were all 100%. Several P.aeruginosa and A. baumannii strains were resistant to all tested antibiotics except polymyxin B. CONCLUSIONS: The pathogen profile is different in different types of infection. The prevalence of multi-drug resistant A. baumannii is high, which is still a key problem of nosocomial infection. Tigecycline remains relatively high activity against gram-positive cocci and gram-negative bacteria (except P. aeruginosa and P. mirabilis) in vitro.

[Analysis of resistance tendency of bloodstream-infecting pathogens in China].

OBJECTIVE: To investigate the resistance profiles and the trend of bloodstream-infecting pathogens isolated from hospitalized patients during 2004-2010. METHODS: The bloodstream isolates were collected from 18 hospitals in 17 cities. Minimum inhibition concentrations (MIC) were determined using the agar dilution method recommended by CLSI (Clinical and Laboratory Standards Institute), and susceptibility results were analyzed according to the 2011 CLSI guideline. RESULTS: Among the 2004-2005, 2007-2008 and 2009-2010 periods, the proportions of clinical isolates were similar; 43.1% (149 isolates), 34.0% (151 isolates) and 47.5% (776 isolates) for Gram positive strains, 56.9% (197 isolates), 66.0% (293 isolates) and 52.5% (858 isolates) for Gram negative strains, respectively. The isolating rate of MRSA was 54.1% (20/37) in 2007-2008, which was the highest among the 3 periods during 2004 to 2010, while it decreased in 2009-2010 (36.5%, 62/170). The MRCNS proportions were similar across the 3 periods. One (1.8%) vancomycin-resistant Enterococcus faecium and 1 linezolid-resistant Enterococcus faecalis were found. Although the isolating rates of penicillin non-sensitive strains (oral) were similar between 2009-2010 and 2007-2008 [54.5% (6/11) and 53.9% (7/13), respectively], the resistant rates increased from 0% in 2007-2008 to 30.8% (4/13) in 2009-2010. The results were similar according to the non-meningitis criterion (IV), and the susceptibility rates decreased from 100.0% (11 isolates) in 2007-2008 to 84.6% (11/13) in 2009-2010. ESBL-harboring strains in E. coli were similar among the 3 periods during 2004 to 2010 [66.7% (30/45), 73.2% (71/97) and 67.9% (233/343), respectively]. ESBL-producing strains in Klebsilla pnuemoniae decreased year after year, 72.4% (21/29), 50.0% (18/36) and 41.1% (65/158) in 2004-2005, 2007-2008 and 2009-2010, respectively. Except that the sensitive rate of Enterobacter cloacae to ertapenem was 80% (32/40), the sensitive rates of other strains to carbapenems were still above 90% and the resistance rates were less than 5%. Acinetobacter baumannii had the highest multi-drug resistance rate (81.8%, 81/99). One strain (1.0%, 1/99) of Acinetobacter baumannii isolated in 2009-2010 was reported to be pan-resistant. CONCLUSIONS: We are facing a more serious situation of bacterial resistance. Acinetobacter baumannii resistance was most serious, usually with the characteristics of multiple drug resistance, and even pan-resistance. Carbapenems remain to be the most effective against enterobacteriaceae. Strains resistant to novel antibiotics (linezolid and tigecycline) have emerged.

The use of pleural fluid procalcitonin and C-reactive protein in the diagnosis of parapneumonic pleural effusions: a systemic review and meta-analysis.

BACKGROUND: We aimed to perform a systematic review and meta-analysis of the diagnostic performance of pleural fluid procalcitonin (PCT) or C-reactive protein (CRP) in differentiating parapneumonic effusion in patients with pleural effusion. METHODS: We searched the EMBASE, MEDLINE, and Cochrane database in December 2011. Original studies that reported the diagnostic performance of PCT alone or compared with that of other biomarkers for differentiating the characteristics of pleural effusion were included. RESULTS: We found 6 qualifying studies including 780 patients with suspected parapneumonic effusion and 306 confirmed cases of parapneumonic effusion. Six studies examined the diagnostic performance of pleural fluid PCT, 3 also tested for serum PCT, and another 3 tested for serum CRP. The bivariate pooled sensitivity and specificity were as follows 0.67 (95% confidence interval [CI], 0.54-0.78) and 0.70 (95% CI, 0.63-0.76), respectively, for pleural fluid PCT; 0.65 (95% CI, 0.55-0.74) and 0.68 (95% CI, 0.62-0.74), respectively, for serum PCT; and 0.54 (95% CI, 0.47-0.61) and 0.77 (95% CI, 0.72-0.81), respectively, for serum CRP. There was evidence of significant heterogeneity (I(2)=55.0%) for pleural fluid or serum PCT but not for CRP (I(2)=0.0%). CONCLUSION: The existing literature suggests that both pleural fluid and serum PCT tests have low sensitivity and specificity for differentiating parapneumonic effusion from other etiologies of pleural effusion. Compared with PCT, serum CRP has higher specificity and a higher positive likelihood ratio, and thus, it has a higher rule-in value than PCT.

[NDM-1-producing Klebsiella pneumoniae in mainland China].

OBJECTIVE: To investigate the characteristics of New Delhi metallo-beta-lactamase-1 (NDM-1) gene of Klebsiella pneumoniae (K. pneumoniae) emerging in Hunan, and its relationship to antibiotic resistance. METHODS: The clinical strain was isolated from a sputum sample of a child with severe pnemonia and toxic myocarditis who was admitted into a general hospital of Hunan Province. VITEK-2 compact instrument was used for bacterial identification and antibiotic susceptibility test. Modified Hodge test was used for the screening of carbapenemase. EDTA-synergy test and combination disk diffusion test were used for detection of metallo-ß-lactamase (MBL). PCR was performed for amplification of NDM-1 genes and the positive products were sequenced and analyzed with BLAST. Conjugation was also performed to analyze mechanisms of antibiotic resistance. The results of antibiotic susceptibility tests were compared before and after conjugation. RESULTS: The isolated strain was identified as K.pneumoniae. Modified Hodge test, EDTA-synergy test and combination disk diffusion test were all positive for the strain. The homology between gene sequence of PCR amplification products and NDM-1 gene FN396876.1 in the GenBank was 100%. Transconjugant DNA was used as template for the amplification of NDM-1 gene. The amplification products were sequenced and found to be the same as the NDM-1 gene amplification product of the donor strain. The MIC of transconjugant E.coli J53 (NDM-1) to all the ß-lactams increased significantly compared with the recipient strain E.coli J53. The MIC of ertapenem and imipenem increased by more than 8 times, while the MIC of ceftazidime and ceftriaxone increased by more than 64 times. CONCLUSIONS: This study first identified a strain of K. pneumoniae carrying NDM-1 in mainland China. NDM-1 gene can be transmitted among different strains and causes extensively drug-resistance to ß-lactams.

Prevalence of Escherichia coli ST1193 Causing Intracranial Infection in Changsha, China.

ST1193 is an emerging new virulent and resistant clone among Escherichia coli with a tendency to spread rapidly across the globe. However, the prevalence of intracranial infection-causing E. coli ST1193 is rarely reported. This study aimed at determining the prevalence of E. coli ST1193 isolates, causing intracranial infections in Changsha, central China. A total of 28 E. coli isolates were collected from the cerebrospinal fluid of patients with intracranial infection over a four-year period. All isolates were differentiated using multilocus sequence typing (MLST), and phylogenetic grouping, and tested for antibiotic resistance. MLST analysis showed 11 sequence types (ST) among the 28 E. coli isolates. The most prevalent ST was B2-ST1193 (28.6%, 8/28), followed by B2-ST131 (21.4%, 6/28) and F-ST648 (10.7%, 3/28). Of the eight ST1193 isolates, three carried CTX-M-55, and one carried CTX-M-27. All eight ST1193 isolates were resistant to Ciprofloxacin, showing gyrA1AB/parC4A mutations. Two ST1193 isolates carried the aac(6')-Ib-cr gene. All ST1193 isolates were recovered from infants with meningitis, with a fatal outcome for one three-month-old infant. ST1193 has emerged as the predominant type of E. coli strain causing intracranial infections in Changsha, China. This study highlights the importance of implementing appropriate surveillance measures to prevent the spread of this emerging public health threat.

Community Fecal Carriage and Molecular Epidemiology of Extended-Spectrum ß-Lactamase- and Carbapenemase-Producing Escherichia coli from Healthy Children in the Central South China.

Background: Fecal carriage of extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-EC) and carbapenemase-producing E. coli (CP-EC) is well reported among hospitalized adults and children. However, there are few studies on the carriage prevalence and ESBL-EC and CP-EC genotypes among healthy children in China. Patients and Methods: Stool samples were collected from 330 students in 2021 from three randomly selected primary schools in Changsha, China. ESBL-EC and CP-EC were screened using CHROMagarTM chromogenic plates. ESBL and carbapenemase production was confirmed using the double-disc synergy test and a modified carbapenem inactivation method, respectively. Antimicrobial susceptibility was tested using the broth microdilution method. Resistance determinants, virulence factors, and phylogenetic groups were determined by PCR and sequencing. Multi-locus sequence typing (MLST) was performed (seven housekeeping genes were amplified and sequenced) on the phylogenic group B2 E. coli to detect high-risk clonal strains such as ST131 E. coli. Then, ST131 E. coli were characterized based on ST131 clades, O-type, and fimH alleles. Results: In total, 118 (35.8%) ESBL-EC and 3 (0.9%) CP-EC were isolated. bla CTX-M was the most common genotype (27.1%), identified in all ESBL-EC, except one, which carried bla SHV-12. One isolate with mcr-1 was found amongst ESBL-EC, whereas all three CP-EC carried bla NDM-1. The predominant sequence type (ST) clones in group B2 were ST131 and ST1193. The prevalence of ST131 E. coli was 9.9%, displaying serotypes O16 and O25b, fimH alleles 30, 41, and 89, and ST131 clades A and C1-M27. Conclusion: In this study, high carriage rate of ESBL-EC was found among healthy children, and the dominant ESBL was CTX-M-14. In addition, high-risk clones (ST131 and ST1193) were also detected. This emphasizes the importance of monitoring ESBL-EC in community settings.

Comparative Evaluation of Seven Tigecycline Susceptibility Testing Methods for Carbapenem-Resistant Enterobacteriaceae.

PURPOSE: Carbapenem-resistant Enterobacteriaceae (CRE) strains are extensively resistant to most antibiotics. Tigecycline is one of the few effective drugs that can be used to treat infections caused by CRE. The aim of this study was to evaluate the accuracy of different methods for detecting the susceptibility of CRE to tigecycline. METHODS: Seven commonly used drug susceptibility testing methods were compared and evaluated for the ability to determine CRE tigecycline susceptibility: broth microdilution (BMD), agar dilution method (ADM), disk diffusion method, Etest, MicroScan, Vitek2 COMPACT, and BD Phoenix 100. RESULTS: The minimum inhibitory concentration (MIC) of tigecycline to inhibit 50% and 90% of CRE growth (MIC50 and MIC90, respectively) assessed by ADM and BD Phoenix 100 was the same as that determined by the reference method, BMD. The MIC50 was 2 µg/mL, and the MIC90 was 4 µg/mL. The highest number of susceptible strains was detected by MicroScan, followed by BMD, Etest, ADM, BD Phoenix 100, Vitek2 COMPACT, and disk diffusion method, in descending order. No significant differences were observed among the tigecycline susceptibility results (P > 0.05) obtained from MicroScan, Etest, BD Phoenix 100, and BMD. BMD confirmed that 82.0% of strains were susceptible to tigecycline. ADM, MicroScan, and BD Phoenix 100 yielded the categorical agreement of 96%, 92%, and 93%, respectively. No method was found to present any very major errors (VMEs), and only the Vitek2 COMPACT yielded major errors (MEs) greater than 3%. CONCLUSION: Among the seven methods tested, the ADM, MicroScan, and BD Phoenix 100 methods were accurate for determining the tigecycline susceptibility of CRE. MicroScan was acceptable with better performance than other methods.

Fructose-coated Ångstrom silver prevents sepsis by killing bacteria and attenuating bacterial toxin-induced injuries.

Serious infection caused by multi-drug-resistant bacteria is a major threat to human health. Bacteria can invade the host tissue and produce various toxins to damage or kill host cells, which may induce life-threatening sepsis. Here, we aimed to explore whether fructose-coated Ångstrom-scale silver particles (F-AgÅPs), which were prepared by our self-developed evaporation-condensation system and optimized coating approach, could kill bacteria and sequester bacterial toxins to attenuate fatal bacterial infections. Methods: A series of in vitro assays were conducted to test the anti-bacterial efficacy of F-AgÅPs, and to investigate whether F-AgÅPs could protect against multi-drug resistant Staphylococcus aureus (S. aureus)- and Escherichia coli (E. coli)-induced cell death, and suppress their toxins (S. aureus hemolysin and E. coli lipopolysaccharide)-induced cell injury or inflammation. The mouse models of cecal ligation and puncture (CLP)- or E. coli bloodstream infection-induced lethal sepsis were established to assess whether the intravenous administration of F-AgÅPs could decrease bacterial burden, inhibit inflammation, and improve the survival rates of mice. The levels of silver in urine and feces of mice were examined to evaluate the excretion of F-AgÅPs. Results: F-AgÅPs efficiently killed various bacteria that can cause lethal infections and also competed with host cells to bind with S. aureus α-hemolysin, thus blocking its cytotoxic activity. F-AgÅPs inhibited E. coli lipopolysaccharide-induced endothelial injury and macrophage inflammation, but not by directly binding to lipopolysaccharide. F-AgÅPs potently reduced bacterial burden, reversed dysregulated inflammation, and enhanced survival in mice with CLP- or E. coli bloodstream infection-induced sepsis, either alone or combined with antibiotic therapy. After three times injections within 48 h, 79.18% of F-AgÅPs were excreted via feces at the end of the 14-day observation period. Conclusion: This study suggests the prospect of F-AgÅPs as a promising intravenous agent for treating severe bacterial infections.

Identification of blaOXA-128 and blaOXA-129, two novel OXA-type extended-spectrum-ß-lactamases in Pseudomonas aeruginosa, in Hunan Province, China.

We collected 97 non-repetitive carbapenemases-sensitive clinical isolates of Pseudomonas aeruginosa in Human Province, China, during the period of October 2006 to January 2007. From these isolates, we identified two novel oxacillin-hydrolysing (OXA) type extended-spectrum-ß-lactamases (ESBLs): bla OXA-128 and bla OXA-129, which contain the mutations of I89V from bla OXA-56 and K134N from bla OXA-10, respectively. Clinical isolates containing either bla OXA-128 or bla OXA-129 show resistance to cephamycin-class antibiotics but sensitive to carbapenem-class antibiotics. The occurrence of novel OXA-type lactamases suggests a regional prevalent pattern of ESBLs Pseudomonas aeruginosa in this area.

[Cytomegalovirus infection and immunosuppressant treatment in allogeneic hematopoietic stem cell transplantation recipients].

OBJECTIVE: To explore the correlation between peripheral blood cytomegalovirus (CMV) DNA level and cyclosporine A (CsA) plasma concentration among allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients who received immunosuppressant treatment, and to evaluate the potential clinical value. METHODS: A total of 32 allo-HSCT patients were enrolled and their data were analyzed retrospectively. Ganciclovir was used to prevent CMV infection before the transplantation. Routine fluorescence PCR was admitted to test the blood CMV DNA level. The patients were divided into 2 groups: a CMV DNA positive group and a CMV DNA negative group. Enzyme multiplied immunoassay technique was adopted regularly to monitor the blood CsA concentration. The correlation between CMV DNA level and CsA concentration was analyzed. RESULTS: The CMV infection rate in patients who received allo-HSCT was 53.13%. The blood CsA concentration in the CMV DNA positive group was significantly higher than that in the CMV DNA negative group (P<0.05). Through the ROC curve, the area under the curve on Day 1, 7, and 14 had statistical significance compared with 0.5, and the corresponding blood CsA concentration was 203.15, 215.55, and 302.65 ng/mL, respectively. CONCLUSION: Immunosuppressive drug concentration can affect the dynamic changes of CMV DNA. High blood CsA concentration may be one of the reasons for CMV infection. Monitoring the blood CsA concentration may provide guidance for clinical treatment.