Successful rescue of disseminated Nocardia infection with multiple abscesses in a patient with membranous nephropathy after cardiopulmonary resuscitation: A three-year follow-up.

Nocardiosis manifests as an opportunistic infection, primarily affecting individuals who are immunocompromised and susceptible to the infection. We present a case study of one patient with nephrotic syndrome and membranous nephropathy, who underwent treatment with prednisone and cyclosporine in 2016. In early 2017, the patient was diagnosed with a "fungal infection" and discontinued the use of cyclosporine. After one month of anti-infection therapy, a cranial magnetic resonance imaging scan showed multiple abscesses in the right temporal region. The diagnosis of nocardiosis was confirmed based on the presence of metastatic abscess masses, multiple lung and brain lesions, and a positive culture of Nocardia in the drainage. We changed the anti-infection therapy to a combination of trimethoprim-sulfamethoxazole (TMP-SMX), minocycline, and voriconazole. However, the patient experienced a sudden cardiac arrest and subsequently recovered after cardiopulmonary resuscitation. During the five-month follow-up period following the discharge, the patient displayed an enhanced nutritional status and stable renal function. The focal infection ultimately resolved during the subsequent three years. Neuro-infection caused by Nocardia should be considered in immunocompromised patients, and TMP-SMX is the preferred initial therapy; however, because of the high mortality rate, a long-term combination therapy with imipenem, cefotaxime, amikacin, and TMP-SMX is suggested.

Emergence of multiple fluconazole-resistant Candida parapsilosis sensu stricto clones with persistence and transmission in China.

OBJECTIVES: We explored the epidemiological and molecular characteristics of Candida parapsilosis sensu stricto isolates in China, and their mechanisms of azole resistance. METHODS: Azole susceptibilities of 2318 non-duplicate isolates were determined using CLSI broth microdilution. Isolates were genotyped by a microsatellite typing method. Molecular resistance mechanisms were also studied and functionally validated by CRISPR/Cas9-based genetic alterations. RESULTS: Fluconazole resistance occurred in 2.4% (n = 56) of isolates, and these isolates showed a higher frequency of distribution in ICU inpatients compared with susceptible isolates (48.2%, n = 27/56 versus 27.8%, 613/2208; P = 0.019). Microsatellite-genotyping analysis yielded 29 genotypes among 56 fluconazole-resistant isolates, of which 10 genotypes, including 37 isolates, belonged to clusters, persisting and transmitting in Chinese hospitals for 1-29 months. Clusters harbouring Erg11Y132F (5/10; 50%) were predominant in China. Among these, the second most dominant cluster MT07, including seven isolates, characteristically harbouring Erg11Y132F and Mrr1Q625K, lent its carriage to being one of the strongest associations with cross-resistance and high MICs of fluconazole (>256 mg/L) and voriconazole (2-8 mg/L), causing transmission across two hospitals. Among mutations tested, Mrr1Q625K led to the highest-level increase of fluconazole MIC (32-fold), while mutations located within or near the predicted transcription factor domain of Tac1 (D440Y, T492M and L518F) conferred cross-resistance to azoles. CONCLUSIONS: This study is the first Chinese report of persistence and transmissions of multiple fluconazole-resistant C. parapsilosis sensu stricto clones harbouring Erg11Y132F, and the first demonstration of the mutations Erg11G307A, Mrr1Q625K, Tac1L263S, Tac1D440Y and Tac1T492M as conferring resistance to azoles.

Tandem gene duplications contributed to high-level azole resistance in a rapidly expanding Candida tropicalis population.

Invasive diseases caused by the globally distributed commensal yeast Candida tropicalis are associated with mortality rates of greater than 50%. Notable increases of azole resistance have been observed in this species, particularly within Asia-Pacific regions. Here, we carried out a genetic population study on 1571 global C. tropicalis isolates using multilocus sequence typing (MLST). In addition, whole-genome sequencing (WGS) analysis was conducted on 629 of these strains, comprising 448 clinical invasive strains obtained in this study and 181 genomes sourced from public databases. We found that MLST clade 4 is the predominant azole-resistant clone. WGS analyses demonstrated that dramatically increasing rates of azole resistance are associated with a rapid expansion of cluster AZR, a sublineage of clade 4. Cluster AZR isolates exhibited a distinct high-level azole resistance, which was induced by tandem duplications of the ERG11A395T gene allele. Ty3/gypsy-like retrotransposons were found to be highly enriched in this population. The alarming expansion of C. tropicalis cluster AZR population underscores the urgent need for strategies against growing threats of antifungal resistance.

A Rapid Carbapenemase Genes Detection Method with Xpert Carba-R from Positive Blood Cultures Compared with NG-Test Carba 5 and Sequencing.

Objective: The objective of the current study was to evaluate the performance of Xpert Carba-R for the direct detection and identification of carbapenemase genes from positive blood cultures. Methods: Pathogens which extracted from positive blood cultures and identified using MALDI-TOF MS as Enterobacterales were included in this study. Xpert Carba-R was used for the rapid detection of carbapenemase genes from positive blood cultures. NG-Test CARBA 5 and polymerase-chain reaction (PCR) sequencing were used for the detection of carbapenemases and carbapenemase genes in positive blood culture isolates, respectively. Finally, antibiotic susceptibility tests were conducted using the VITEK-2 Compact system. Results: A total of 133 positive blood cultures of Enterobacterales were collected and 27 of them were detected to carry carbapenemase genes using Xpert Carba-R. In comparison with PCR sequencing results, the sensitivity and specificity of Xpert Carba-R and NG-Test CARBA 5 were calculated as 100%. Additionally, Xpert Carba-R could significantly shorten the turnaround time by directly detecting positive blood cultures comparing with NG-Test CARBA 5. For 27 carbapenem-producing strains, the resistance rates of carbapenems and aztreonam were 96.3% and 92.6%, respectively. Strains carrying the blaKPC gene were all sensitive to ceftazidime-avibactam. All strains were sensitive to tigecycline and colistin. Conclusion: Xpert Carba-R is suitable for the rapid detection of main carbapenemase genes from positive blood cultures with high sensitivity and specificity. In comparison with NG-Test CARBA 5 and PCR sequencing methods, the timely and convenient method can be a useful test to guide optimal therapy and infection control.

Continual Decline in Azole Susceptibility Rates in Candida tropicalis Over a 9-Year Period in China.

BACKGROUND: There have been reports of increasing azole resistance in Candida tropicalis, especially in the Asia-Pacific region. Here we report on the epidemiology and antifungal susceptibility of C. tropicalis causing invasive candidiasis in China, from a 9-year surveillance study. METHODS: From August 2009 to July 2018, C. tropicalis isolates (n = 3702) were collected from 87 hospitals across China. Species identification was carried out by mass spectrometry or rDNA sequencing. Antifungal susceptibility was determined by Clinical and Laboratory Standards Institute disk diffusion (CHIF-NET10-14, n = 1510) or Sensititre YeastOne (CHIF-NET15-18, n = 2192) methods. RESULTS: Overall, 22.2% (823/3702) of the isolates were resistant to fluconazole, with 90.4% (744/823) being cross-resistant to voriconazole. In addition, 16.9 (370/2192) and 71.7% (1572/2192) of the isolates were of non-wild-type phenotype to itraconazole and posaconazole, respectively. Over the 9 years of surveillance, the fluconazole resistance rate continued to increase, rising from 5.7 (7/122) to 31.8% (236/741), while that for voriconazole was almost the same, rising from 5.7 (7/122) to 29.1% (216/741), with no significant statistical differences across the geographic regions. However, significant difference in fluconazole resistance rate was noted between isolates cultured from blood (27.2%, 489/1799) and those from non-blood (17.6%, 334/1903) specimens (P-value < 0.05), and amongst isolates collected from medical wards (28.1%, 312/1110) versus intensive care units (19.6%, 214/1092) and surgical wards (17.9%, 194/1086) (Bonferroni adjusted P-value < 0.05). Although echinocandin resistance remained low (0.8%, 18/2192) during the surveillance period, it was observed in most administrative regions, and one-third (6/18) of these isolates were simultaneously resistant to fluconazole. CONCLUSION: The continual decrease in the rate of azole susceptibility among C. tropicalis strains has become a nationwide challenge in China, and the emergence of multi-drug resistance could pose further threats. These phenomena call for effective efforts in future interventions.

Characterization of Carbapenem-Resistant Klebsiella pneumoniae ST15 Clone Coproducing KPC-2, CTX-M-15 and SHV-28 Spread in an Intensive Care Unit of a Tertiary Hospital.

OBJECTIVE: Nosocomial infection caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) is a great threat to severely ill patients. Here we report an outbreak of K. pneumoniae ST15 isolates co-producing KPC-2, CTX-M-15, and SHV-28 in the cardiac surgery intensive care unit (CSICU) of a tertiary hospital. MATERIALS AND METHODS: From November 2019 to August 2020, all non-duplicated CRKP isolates were collected from the CSICU. The VITEK-2 compact system was used for bacterial identification and antimicrobial susceptibility testing. Clinical data were retrieved from electronic case records. All strains were also subjected to antibiotic resistance genes detection. Clonal relationships were analyzed by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). RESULTS: A total of 28 non-duplicated CRKP isolates were collected, including 23 strains belonging to ST15 and 5 strains belonging to ST11. All ST15 isolates were susceptible to amikacin, tigecycline, polymyxin B and ceftazidime/avibactam, but resistant to carbapenems, cephalosporins, quinolones, tobramycin and gentamicin. The detection of resistant determinants showed that 21 strains of ST15 CRKP co-harboured blaKPC-2, blaCTX-M-15, blaSHV-28, blaTEM-1, blaOXA-1 and aac(6')-Ib-cr. All the 28 CRKP isolates were classified into five PFGE patterns (A, B, C, D and E), of which type A and B belonged to ST15 and type C, D and E belonged to ST11. PFGE type A was the predominant clonotype of this nosocomial infection and belonged to ST15. CONCLUSION: K. pneumoniae ST15 co-producing KPC-2, CTX-M-15, SHV-28, TEM-1, OXA-1 and aac(6')-Ib-cr is the predominant clone spread in the CSICU. Surveillance and comprehensive infection control measures should be strengthened in clinical practice.

Long-Term Continuous Antimicrobial Resistance Surveillance Among Nosocomial Gram-Negative Bacilli in China from 2010 to 2018 (CMSS).

PURPOSE: The Chinese Meropenem Surveillance Study (CMSS) was conducted every 2 years from 2010 to 2018 to monitor the antimicrobial activity of commonly used antimicrobial agents against nosocomial gram-negative bacilli in China. METHODS: From 2010 to 2018, 6,537 gram-negative bacilli were collected from 14 teaching hospitals. The minimum inhibitory concentrations (MICs) of meropenem and other antimicrobial agents were determined using the agar dilution and broth microdilution methods. RESULTS: Continuous surveillance indicated that, except for Klebsiella pneumoniae, the susceptibility of Enterobacterales to carbapenems was relatively stable over time. Carbapenems had the highest activity against the tested isolates, with MIC90 values (MIC for 90% of organisms) ranging from 0.032 mg/L to 8 mg/L. More than 90% of bacteria were susceptible to either meropenem or imipenem; more than 80% were susceptible to ertapenem. The prevalence of extended-spectrum beta-lactamase (ESBL)-producing E. coli, K. pneumoniae, and P. mirabilis each year was 50.4-64.3%, 18-41.2%, and 1.9-33.8%, respectively. The prevalence of carbapenem-resistant K. pneumoniae (CRKP) and carbapenem-resistant Acinetobacter baumannii (CRAB) continued to increase significantly over time, from 7.6% to 21.2% and 64.6% to 69.3%, respectively. The prevalence of CRKP was higher from urinary tract infections (25.4%) than from bloodstream infections (14.2%), intra-abdominal infections (14.5%), and respiratory infections (14.4%). In total, 129 CRKP isolates were evaluated by PCR; of these, 92 (71.3%) carried the bla KPC-2 gene. Colistin maintained very high in vitro antimicrobial activity against P. aeruginosa and A. baumannii (more than 95% of isolates exhibited susceptibility at all timepoints). CONCLUSION: The results indicate an increase in K. pneumoniae resistance to carbapenems over time, mainly owing to KPC-type carbapenemase production. A. baumannii was severely resistant to carbapenems in China. Ongoing MIC-based resistance surveillance, like CMSS, provides additional data for clinical anti-infective treatment.

Non-O1, Non-O139 Vibrio cholerae (NOVC) Bacteremia: Case Report and Literature Review, 2015-2019.

Non-O1, non-O139 Vibrio cholerae (NOVC) does not agglutinate with O1 and O139 antisera and can cause intestinal and extraintestinal infections in immunocompromised individuals. NOVC bacteremia has the highest mortality among NOVC infections, and the number of reports has increased in recent years. Nevertheless, some clinicians are poorly informed about this disease. Herein, we describe a documented case of NOVC bacteremia in a male patient with impaired liver function. Blood cultures revealed the presence of V. cholerae, but this strain showed self-coagulation on the serum agglutination test. To our knowledge, this phenomenon is unreported among cases of NOVC infections. This pathogen was finally confirmed as NOVC via PCR. Because the patient worked as a garbage transporter, he was likely infected after contact with contaminated water through a foot wound. The patient developed septic shock shortly after admission and ultimately died from the illness. This paper reviews 23 cases of NOVC bacteremia from 2015 to 2019. To improve the accuracy of identifying NOVC and analyze its virulence factors, relevant detection methods were reviewed and analyzed.

A Confirmed Catheter-Related Blood Stream Infection (CRBSI) in an Immunocompetent Patient Due to Myroides odoratimimus: Case Report and Literature Review.

The genus Myroides are gram-negative bacilli which are completely aerobic, non-motile, non-fermenting and yellow-pigmented with a characteristic fruity odor. Myroides species are widely found in the environment, especially in water and soil, and are considered as low-grade opportunistic pathogens for humans. Myroides infections are most commonly seen in immunocompromised patients and only rarely occur in immunocompetent patients. We here report the first confirmed catheter-related bloodstream infection (CRBSI) due to Myroides odoratimimus in an immunocompetent patient. We also review the literature related to Myroides infections.

Characterization Of bla NDM-5-Positive Escherichia coli Prevalent In A University Hospital In Eastern China.

PURPOSE: The emergence and spread of carbapenem-resistant Enterobacteriaceae deserves special concern worldwide. Unlike the epidemiological characteristics reported in other studies, we found that the production of New Delhi metallo-ß-lactamase 5 was the main mechanism for the resistance of Escherichia coli to carbapenems. METHODS: All carbapenem-resistant strains were collected from July 2017 to July 2018 of the First Affiliated Hospital of Nanjing Medical University. The presence of carbapenemase-encoding genes was detected using PCR and gene sequencing. Genetic relatedness of the bla NDM-5-positive E. coli strains was determined with PFGE and MLST. Susceptibility profiles were measured with broth microdilution method and E-test strips. Transferability features of bla NDM-5 gene were assessed by conjugation experiments, S1-PFGE, southern blotting and PCR-based replicon typing methods. The genetic structures surrounding bla NDM-5 were acquired by whole genome sequencing and PCR mapping. RESULTS: Among the 28 carbapenem-resistant E. coli strains, 18 (64%) were verified as NDM-5 producers. The 18 bla NDM-5-positive E. coli strains showed high resistance to most antibiotics, but 100% were sensitive to colistin and tigecycline. In addition, the 18 bla NDM-5-positive E. coli strains belonged to eight STs, among which ST167, ST410 and ST101 were found to cause clonal spread in the hospital. Further studies found that the bla NDM-5 gene was located on an IncX3-type plasmid, and all plasmids harbored an IS3000-ΔISAba125-IS5-bla NDM-5-bleMBL-trpF-dsbC-IS26 structure. CONCLUSION: The clonal spread of bla NDM-5-positive E. coli strains and horizontal dissemination via the pNDM-MGR 194-like plasmids should draw more attention. Appropriate infection control operations should be performed to prevent the further spread of bla NDM-5.

Cytotoxic and antibacterial polyketide-indole hybrids synthesized from indole-3-carbinol by Daldinia eschscholzii.

Two skeletally undescribed polyketide-indole hybrids (PIHs), named indolchromins A and B, were generated from indole-3-carbinol (I3C) in the fungal culture (Daldinia eschscholzii). The indolchromin structures were elucidated mainly by their 1D and 2D NMR spectra with the former confirmed by the single-crystal X-ray crystallographic analysis. Each indolchromin alkaloid was chirally separated into four isomers, whose absolute configurations were assigned by comparing the recorded circular dichroism (CD) spectra with the electronic CD (ECD) curves computed for all optional stereoisomers. Furthermore, the indolchromin construction pathways in fungal culture were clarified through enzyme inhibition, precursor feeding experiment, and energy calculation. The cascade reactions, including decarboxylative Claisen condensation catalyzed by 8-amino-7-oxononanoate synthase (AONS), C(sp 3)-H activation, double bond migration, and Michael addition, all undergone compatibly during the fungal cultivation. In an MIC range of 1.3-8.6 µmol/L, (2S,4R)- and (2R,4S)-indolchromin A and (2R,4S)-indolchromin B are inhibitory against Clostridium perfringens, Clostridium difficile, Veillonella sp., Bacteroides fragilis, and Streptococcus pyogenes. (2R,4S)-Indolchromin A and (2S,4S)-indolchromin B were cytotoxic against the human breast cancer cell line MDA-MB-231 with IC50 values of 27.9 and 131.2 nmol/L, respectively, with the former additionally active against another human breast cancer cell line MCF-7 (IC50 94.4 nmol/L).

Inusual endocarditis grave por Kodamaea ohmeriasociada a linfohistiocitosis hemofagocítica / A rare life-threatening kodamaea ohmeriendocarditis associated with hemophagocytic lymphohistiocytosis

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Serotype distribution and antibiotic resistance of Streptococcus pneumoniae isolates from 17 Chinese cities from 2011 to 2016.

BACKGROUND: Streptococcus pneumoniae, the leading pathogen of bacterial infections in infants and the elderly, is responsible for pneumococcal diseases with severe morbidity and mortality. Emergence of drug-resistant strains presented new challenges for treatment and prevention. Vaccination has proven to be an effective means of preventing pneumococcal infection worldwide. Detailed epidemiological information of antibiotic susceptibilities and serotype distribution will be of great help to the management of pneumococcal infections. METHODS: A total of 881 S. pneumoniae isolates were collected from patients at 23 teaching hospitals in 17 different cities from 2011 to 2016. The main specimen types included sputum, blood, broncho-alveolar lavage fluid, pharyngeal swabs, and cerebrospinal fluid. Minimum inhibitory concentrations (MICs) were determined using the agar dilution method. Capsular serotypes were identified using latex agglutination and quellung reaction test. Molecular epidemiology was investigated using multilocus sequence typing. RESULTS: S. pneumoniae isolates were highly resistant to macrolides, tetracycline, and trimethoprim/sulfamethoxazole. The rate of resistance to penicillin was 51.6% (oral breakpoint). However, levofloxacin and moxifloxacin maintained excellent antimicrobial activity and all of the isolated strains were susceptible to vancomycin. Twenty-two serotypes were identified among the 881 isolates. Prevalent serotypes were 19F (25.7%), 19A (14.0%), 15 (6.8%), 6B (3.6%), 6A (3.0%), and 17 (2.8%). The overall vaccine coverage rates for 7- and 13-valent pneumococcal conjugate vaccines were 37.5% and 58.3%, respectively. Vaccine coverage rates in young children and economically underdeveloped regions were higher than those in older adults and developed regions. Vaccine-covered serotypes demonstrated higher resistance compared with uncovered serotypes. Molecular epidemiological typing demonstrated that S. pneumoniae showed significant clonal dissemination and that ST271 (120, 28.3%), ST320 (73, 17.2%) and ST81 (27, 6.6%) were the major STs. CONCLUSIONS: High resistance to clinical routine antibiotics was observed for all 881 S. pneumoniae strains. Drug resistance varied among different serotypes and age groups. Prevalent serotypes among the isolates were 19F, 19A, 15, 6B, 6A, and 17. Community-acquired strains should also be included in future studies to gain a better understanding of the prevalence and resistance of S. pneumoniae in China.

[Antimicrobial resistance monitoring of gram-negative bacilli isolated from 15 teaching hospitals in 2014 in China].

OBJECTIVE: To investigate the current situation of antimicrobial resistance of nosocomial gram-negative bacilli in 2014 in China. METHODS: About 1 430 consecutive and non-repetitive strains of gram-negative bacilli were isolated from 15 teaching hospitals from March to August in 2014. All of these isolates were sent to the central laboratory for reidentification and susceptibility testing. The minimal inhibitory concentration (MIC) of meropenem and other antibacterial agents were determined by agar dilution method. The data were analyzed by using WHONET-5.6 software. RESULTS: The activity of antimicrobial agents against Enterobacteriaceae was listed as followings in descending order of susceptibility: meropenem (94.7%, 913/964), amikacin (94.4%, 910/964), imipenem (88.5%, 853/964), ertapenem (87.8%, 847/964), piperacillin-tazobactam (87.2%, 841/964), cefoperazone-sulbactam (86.7%, 836/964), polymyxin B (77%, 742/964), cefepime (74.5%, 718/964), cefiazidime (71.8%, 692/964), levofloxacin (71.1%, 685/964), ciprofloxacin (67.7%, 653/964), minocyline (64.2%, 619/964), ceftriaxone (56.8%, 548/964), cefotaxime (55.8%, 538/964), cefoxitin (45.5%, 439/964). The prevalence of extended-spectrum beta-lactamases (ESBLs) was 57.6% (114/198) in E. coli and 24.6% (49/199) in Klebsiella pneumonia. The sensitivity of E. coli to carbapenems, amikacin, piperacillin-tazobactam, polymyxin B and cefoperazone-sulbactam was all over 80%. However, over 60% E. coli strains were resistant to ciprofloxacin, levofloxacin, ceftriaxone and cefotaxime. Polymyxin B was the most susceptible antibiotic to Klebsiella pneumoniae (99.5% sensitive), followed by amikacin (89.9%), meropenem (86.4%), imipenem (86.4%) and piperacillin-tazobactam (81.9%), while ceftriaxone (60.8%) and cefotaxime (59.8%) were less sensitive. The activity of antimicrobial agents against E. cloacae, E. aerogenes and Citrobacter freundii was listed as followings in descending order of susceptibility: meropenem (96.1%-97.4%), imipenem (95.1%-97.1%), polymyxin B (92.6%-99.0%), cefoperazone/sulbactam (87.3%-92.6%), ertapenem (85.6%-93.3%), piperacillin-tazobactam (65.0%-89.8%). The susceptibility rates of meropenem, cefoperazone-sulbactam, piperacillin-tazobactam, cefepime to Proteus mirabilis, Proteus vulgaris and Morganella morganii were all more than 90.0%. The most active agents against Pseudomonas aeruginosa were polymyxin B (99.5%), followed by amikacin (92.0%) and ciprofloxacin (82.1%). A. baumanni was most susceptible to polymyxin B (99.0%), while resistant to imipenem, meropenem and cefoperazone-sulbactam (29.2%, 28.2% and 29.7% respectively), mediate to minocycline (67.0%). Based on the new breakpoints for cefepime to Enterobacteriaceae, the drug susceptible rates decreased 25.8% to E. coli and 14.7% to E. cloacae. CONCLUSIONS: Carbapenems remain high susceptibility against Enterobacteriaceae, however carbapenem-resistant Enterobacteriaceae (CREs) have emerged. The sensitivity of Enterobacteriaceae against cefepime has been decreased according to the new breakpoint. Multi-drug resistant A. baumanni should be monitored persistently.

Increasing resistance rate to carbapenem among blood culture isolates of Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa in a university-affiliated hospital in China, 2004-2011.

The objective of this study is to investigate the profile of antimicrobial resistance of Gram-negative bacteria in blood cultures from 2004-2011. Pathogens from positive blood cultures were subcultured, and identified in the First Affiliated Hospital of Nanjing Medical University from January 2004 to December 2011. The antibiotic resistance pattern was analyzed by WHONET 5.4. A total of 1224 cases of Gram-negative bacterial isolates were documented, accounting for 38.6% of the total pathogens isolated from positive blood cultures in the 8-year period. The isolation rates of Klebsiella pneumoniae and Acinetobacter baumannii increased nearly three times over the same time span. Most Gram-negative bacteria isolates, except the isolates of Pseudomonas aeruginosa, showed a significantly increased resistance rate to cephalosporins (in particular third/fourth generation cephalosporins). Noteworthy, the antimicrobial resistance of K. pneumoniae, A. baumannii and P. aeruginosa isolates to carbapenem (imipenem and meropenem) was significantly increased and the resistant rate to carbapenem was >80.0% in A. baumannii in 2011. The results from PCR detection for carbapenemases were as follows: 82.8% (24/29) isolates of K. pneumoniae carried the kpc-2 gene; only three metallo-beta-lactamase-positive P. aeruginosa isolates were detected; and 93.1% (67/72) A. baumannii isolates were blaOXA-23 positive. The antimicrobial resistance rate of Gram-negative bacteria isolated from blood cultures significantly increased from 2004 to 2011, with significant resistance to the third/fourth generation cephalosporins and carbapenem.

MALDI-TOF MS versus VITEK 2 ANC card for identification of anaerobic bacteria.

BACKGROUND: Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an accurate, rapid and inexpensive technique that has initiated a revolution in the clinical microbiology laboratory for identification of pathogens. The Vitek 2 anaerobe and Corynebacterium (ANC) identification card is a newly developed method for identification of corynebacteria and anaerobic species. The aim of this study was to evaluate the effectiveness of the ANC card and MALDI-TOF MS techniques for identification of clinical anaerobic isolates. METHODS: Five reference strains and a total of 50 anaerobic bacteria clinical isolates comprising ten different genera and 14 species were identified and analyzed by the ANC card together with Vitek 2 identification system and Vitek MS together with version 2.0 database respectively. 16S rRNA gene sequencing was used as reference method for accuracy in the identification. RESULTS: Vitek 2 ANC card and Vitek MS provided comparable results at species level for the five reference strains. Of 50 clinical strains, the Vitek MS provided identification for 46 strains (92%) to the species level, 47 (94%) to genus level, one (2%) low discrimination, two (4%) no identification and one (2%) misidentification. The Vitek 2 ANC card provided identification for 43 strains (86%) correct to the species level, 47 (94%) correct to the genus level, three (6%) low discrimination, three (6%) no identification and one (2%) misidentification. CONCLUSIONS: Both Vitek MS and Vitek 2 ANC card can be used for accurate routine clinical anaerobe identification. Comparing to the Vitek 2 ANC card, Vitek MS is easier, faster and more economic for each test. The databases currently available for both systems should be updated and further developed to enhance performance.

Emergence of linezolid resistance in a clinical Staphylococcus capitis isolate from Jiangsu Province of China in 2012.

Linezolid (LZD) is an important antimicrobial agent for the treatment of infections caused by Gram-positive organisms, including methicillin-resistant Staphylococci. And until now, LZD resistance in clinical is still rare. Here we reported the first case of LZD resistance Staphylococcus capitis in Jiangsu, China. This strain was isolated from a 92-year old female who received long-term and repeatedly antibiotics treatment because of recurrent pulmonary infections in August 2012. Isolated from blood, the Staphylococcus capitis showed a resistance to LZD with a minimal inhibitory concentration (MIC) of 64 µg/mL, and the followed gene detection showed that the isolates existed C2190T and C2561Y point mutations in the 23S rRNA. Moreover, the isolation was also found carrying the cfr gene.

[Antimicrobial resistance of Gram-negative bacilli isolated from 13 teaching hospitals across China].

OBJECTIVE: To explore the antimicrobial resistance of nosocomial Gram-negative bacilli across China. METHODS: A total of 1247 consecutive and non-repetitive Gram-negative bacilli were isolated from 13 Chinese teaching hospitals from March to August 2012. All isolates were sent to a central laboratory for reidentification and susceptibility testing. The minimal inhibitory concentration (MICs) of meropenem and other antibacterial agents were determined by agar dilution method. And the data were analyzed with WHONET-5.6 software. RESULTS: The activity of antimicrobial agents against Enterobacteriaceae was in the following descending order of susceptibility rate: meropenem (97.5%, 849/871) , amikacin (94.5%, 823/871) , imipenem (93.6%, 815/871) , ertapenem (92.9%, 809/871) , piperacillin/tazobactam (89.9%, 783/871) , cefoperazone/sulbactam (83.5%, 727/871) , cefepime (78.1%, 680/871) , polymyxin B (77.0%, 670/871) , cefiazidime (69.6%, 606/871) , levofloxacin (69.2%, 603/871) , ciprofloxacin (63.6%, 554/871) , minocyline (63.1%, 550/871) , ceftriaxone (55.7%, 485/871) , cefotaxime (54.2%, 472/871) and cefoxitin (51.4%, 448/871) . The prevalence of extended-spectrum beta-lactamase (ESBL) was 64.3% (117/182) in Escherichia coli (E. coli) and 32.1% (60/187) in Klebsiella pneumonia (K. pneumoniae) . The sensitivities of E. coli to meropenem and imipenem were 100%. And over 90% of E. coli was sensitive to ertapenem, amikacin, piperacillin/tazobactam and polymyxin B. However, over 60% of E. coli was resistant to ciprofloxacin, levofloxacin, ceftriaxone and cefotaxime. The susceptibility of K. pneumoniae to meropenem, imipenem, amikacin and polymyxin B maintained at over 90%. The activities of antimicrobial agents against E. cloacae, E. aerogenes and Citrobacter freundii were in the following descending order of susceptibility rate: meropenem (96.0%-100%) , imipenem (96.0%-100%) , polymyxin B (95.8%-100%) , amikacin (92.2%-100%) , ertapenem (85.6%-93.3%) , cefepime (77.8%-93.3%) , cefoperazone/sulbactam (78.4%-90.0%) and piperacillin/tazobactam (65.0%-89.8%) . The most susceptible agent against Acinetobacter baumannii (A. baumannii) was polymyxin B (100%) . The susceptibilities of A.baumannii to imipenem, meropenem and minocyline were 37.8% (65/172) , 36.0% (62/172) and 62.8% (108/172) respectively. The most active agents against Pseudomonas aeruginosa (P. aeruginosa) were polymyxin B (97.2%, 173/178) , followed by amikacin (89.3%, 159/178) and cefiazidime (83.7%, 149/178) . Clinical and Laboratory Standards Institute revised P.aeruginosa susceptibility standard in 2012. The sensitivity of piperacillin/tazobactam changed from 83.7% (149/178) to 77.5% (138/178) . The sensitivity of meropenem decreased from 78.1% ( 139/178 ) to 71.3% ( 127/178 ) while that of imipenem declined from 69.7% (124/178) to 59.6% (106/178) . The prevalence of multi-drug resistant A. baumannii and P. aeruginosa were 65.7% (113/172) and 9.0% (16/178) respectively. CONCLUSIONS: Carbapenems remain highly active against Enterobacteriaceae. Increasing resistance of A. baumannii to all antimicrobial agents is noted. New breakpoint to P.aeruginosa has obvious effects on antimicrobial sensitivity.