Annals of Clinical Microbiology and Antimicrobials最新文献

{"title":"Rapid detection of ceftriaxone-resistant Salmonella by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry combined with the ratio of optical density.","authors":"Chao Fang, Zheng Zhou, Mingming Zhou, Jianping Li","doi":"10.1186/s12941-024-00729-9","DOIUrl":"10.1186/s12941-024-00729-9","url":null,"abstract":"<p><strong>Background: </strong>The increased resistance rate of Salmonella to third-generation cephalosporins represented by ceftriaxone (CRO) may result in the failure of the empirical use of third-generation cephalosporins for the treatment of Salmonella infection in children. The present study was conducted to evaluate a novel method for the rapid detection of CRO-resistant Salmonella (CRS).</p><p><strong>Methods: </strong>We introduced the concept of the ratio of optical density (ROD) with and without CRO and combined it with matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) to establish a new protocol for the rapid detection of CRS.</p><p><strong>Results: </strong>The optimal incubation time and CRO concentration determined by the model strain test were 2 h and 8 µg/ml, respectively. We then conducted confirmatory tests on 120 clinical strains. According to the receiver operating characteristic curve analysis, the ROD cutoff value for distinguishing CRS and non-CRS strains was 0.818 [area under the curve: 1.000; 95% confidence interval: 0.970-1.000; sensitivity: 100.00%; specificity: 100%; P < 10^- 3].</p><p><strong>Conclusions: </strong>In conclusion, the protocol for the combined ROD and MALDI-TOF MS represents a rapid, accurate, and economical method for the detection of CRS.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"70"},"PeriodicalIF":4.6,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11308677/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141900753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term successfull management of recurrent episodes of nontuberculous mycobacterial infection in an apparently healthy Chinese woman","authors":"Angelo Roberto Raccagni, Giovanni Mori, Valeria Poletti de Chaurand, Raffaele Dell’Acqua, Daniela Maria Cirillo, Chiara Oltolini, Benedetta Mazzi, Francesco Scomazzoni, Antonella Castagna, Monica Guffanti","doi":"10.1186/s12941-024-00732-0","DOIUrl":"https://doi.org/10.1186/s12941-024-00732-0","url":null,"abstract":"Disseminated non-tuberculous mycobacteria (dNTM) infections are mostly reported among individuals with an underlying congenital or acquired immunodeficiency or receiving immunosuppressive treatment, but are rarely documented in otherwise healthy subjects. We describe a case of recurrent disseminated mycobacterial infection in an apparently immunocompetent Chinese woman. Mycobacterium szulgai and Mycobacterium avium-complex were identified in distinct episodes. Long-term antimycobacterial therapy was administered given the occurrence of recurrent events when off-treatment. Successful management over more than 10 years and immunologic data are reported. This case-report highlights that dNTM should be suspected also among apparently immunocompetent hosts and that thorough assessment of underling immune-impairments is helpful to define patients’ management. Long-term antimycobacterial therapy and close monitoring is required to grant successful outcomes in case of recurrent dNTM infections.","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"42 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late-onset sepsis in newborns caused by Bacillus Cereus: a case report and literature review.","authors":"Wang Zhang, Caihua Ma, Linghui Hu, Ling Wang, Falin Xu","doi":"10.1186/s12941-024-00712-4","DOIUrl":"10.1186/s12941-024-00712-4","url":null,"abstract":"<p><p>Bacillus cereus is a bacterium capable of causing late-onset neonatal sepsis. By analyzing 11 cases, this study investigates the diagnosis, treatment, and prognosis of Bacillus cereus infections, aiming to provide insights into clinical diagnosis and therapy. The study scrutinized 11 instances of late-onset neonatal sepsis, including two fatalities attributable to Bacillus cereus, one accompanied by cerebral hemorrhage. An examination and analysis of these cases' symptoms, signs, laboratory tests, and treatment processes, along with a review of related literature from 2010 to 2020, revealed a high mortality rate of 41.38% in non-gastrointestinal infections caused by Bacillus cereus. Our findings underscore the critical importance of rapid diagnosis and effective antimicrobial therapy in reducing mortality rates. Once the source of infection is identified, implementing effective infection control measures is essential.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"66"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11282708/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141764924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Co-existence of two plasmids harboring transferable resistance-nodulation-division pump gene cluster, tmexCD1-toprJ1, and colistin resistance gene mcr-8 in Klebsiella pneumoniae.","authors":"Xiaofen Mo, Hui Zhang, Junfeng Fan, Linna Xu, Hao Fu, Junpeng Yue, Kaixuan Dong, Qixia Luo, Fen Wan","doi":"10.1186/s12941-024-00727-x","DOIUrl":"10.1186/s12941-024-00727-x","url":null,"abstract":"<p><strong>Background: </strong>The emergence of plasmid-mediated mobile colistin resistance (mcr) gene poses a great challenge to the clinical application of polymyxins. To date, mcr-1 to mcr-10 have been found in animals, humans, and the environment. Among them, mcr-8 was first identified in Klebsiella pneumoniae (K. pneumoniae) of swine origin, and then mcr-8.1 to mcr-8.5 were successively identified. Notably, K. pneumoniae is the major host of the mcr-8 gene in both animals and humans. This study aims to explore the characteristics of K. pneumoniae strains carrying the mcr-8 gene and tmexCD1-toprJ1 gene cluster and investigate the correlation between these two antibiotic resistance genes.</p><p><strong>Methods: </strong>The isolates from the poultry farms and the surrounding villages were identified by mass spectrometer, and the strains positive for mcr-1 to mcr-10 were screened by polymerase chain reaction (PCR). The size of the plasmid and the antimicrobial resistance genes carried were confirmed by S1-nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern hybridization, and the transferability of the plasmid was verified by conjugation experiments. Antimicrobial susceptibility testing (AST) and whole genome sequencing (WGS) were used to characterize the strains.</p><p><strong>Results: </strong>Two K. pneumoniae isolates (KP26 and KP29) displaying polymyxin resistance were identified as mcr-8 gene carriers. Besides that, tigecycline-resistant gene cluster tmexCD1-toprJ1 was also found on the other plasmid which conferred strain resistance to tigecycline. Through epidemiological analysis, we found that the mcr-8 gene has dispersed globally, circulating in the human, animals, and the environment. Furthermore, our analysis suggests that the coexistence of mcr-8 and tmexCD1-toprJ1 on a single plasmid might evolved through plasmid recombination.</p><p><strong>Conclusions: </strong>Although the mcr-8 and tmexCD1-toprJ1 gene clusters in the two strains of K. pneumoniae in this study were on two different plasmids, they still pose a potential threat to public health, requiring close monitoring and further study.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"67"},"PeriodicalIF":4.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11282740/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141765002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"To evaluate the performance of simultaneous amplification and testing assay for group B Streptococcus detection: comparison with real-time PCR and ddPCR assays.","authors":"Loukaiyi Lu, Yisheng Chen, Qiang Wang, Jing Gao, Chunmei Ying","doi":"10.1186/s12941-024-00726-y","DOIUrl":"10.1186/s12941-024-00726-y","url":null,"abstract":"<p><strong>Background: </strong>To evaluate the performance of simultaneous amplification and testing (SAT) assay for the detection of group B Streptococcus (GBS) in maternal vaginal and perianal swabs compared with real-time polymerase chain reaction (RT-PCR).</p><p><strong>Methods: </strong>We obtained vaginal and perianal swabs from 1474 pregnant women at the Obstetrics and Gynecology Hospital of Fudan University (Shanghai, China) between April 2023 and June 2023. Vaginal and perianal swabs were collected at 35-37 weeks of gestation. Swabs were tested for GBS simultaneously by using the SAT assay and RT-PCR, and a comparative analysis (kappa coefficient) was performed. Furthermore, we conducted additional droplet digital PCR (ddPCR) tests to confirm the results when there were controversial results between SAT and RT-PCR. In addition, we compared the limit of detection, technical specificity, repeatability and reproducibility of SAT-GBS with those of routine RT-PCR assays.</p><p><strong>Results: </strong>In our study, the detection rate of clinical GBS according to the SAT assay was 11.5% (169/1471). The SAT assay showed a sensitivity of 91.8%, a specificity of 99.9%, a diagnostic accuracy of 98.9%, a positive predictive value (PPV) of 99.4% and a negative predictive value (NPV) of 98.8%. The kappa value between RT-PCR and SAT was 0.917.</p><p><strong>Conclusions: </strong>This SAT assay for the detection of group B Streptococcus is not only easy to perform but can also detect GBS sensitively and specifically and may be used in the regular molecular diagnosis of GBS infection among pregnancies.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"65"},"PeriodicalIF":4.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11264765/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141722839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular epidemiology of Acinetobacter baumannii during COVID-19 at a hospital in northern China.","authors":"Xinlin Huang, Nianzhi Ning, Deyu Li, Suming Chen, Liangyan Zhang, Huan Wang, Chunmei Bao, Xiaolan Yang, Boan Li, Hui Wang","doi":"10.1186/s12941-024-00716-0","DOIUrl":"10.1186/s12941-024-00716-0","url":null,"abstract":"<p><strong>Background: </strong>The wide spread of carbapenem-resistance clones of Acinetobacter baumannii has made it a global public problem. Some studies have shown that the prevalence of Acinetobacter baumannii clones can change over time. However, few studies with respect to the change of epidemiological clones in Acinetobacter baumannii during Corona Virus Disease 2019 (COVID-19) were reported. This study aims to investigate the molecular epidemiology and resistance mechanisms of Acinetobacter baumannii during COVID-19.</p><p><strong>Results: </strong>A total of 95 non-replicated Acinetobacter baumannii isolates were enrolled in this study, of which 60.0% (n = 57) were identified as carbapenem-resistant Acinetobacter baumannii (CRAB). The positive rate of the bla_OXA-23 gene in CRAB isolates was 100%. A total of 28 Oxford sequence types (STs) were identified, of which the most prevalent STs were ST540 (n = 13, 13.7%), ST469 (n = 13, 13.7%), ST373 (n = 8, 8.4%), ST938 (n = 7, 7.4%) and ST208 (n = 6, 6.3%). Differently, the most widespread clone of Acinetobacter baumannii in China during COVID-19 was ST208 (22.1%). Further study of multidrug-resistant ST540 showed that all of them were carrying bla_OXA-23, bla_OXA-66, bla_ADC-25 and bla_TEM-1D, simultaneously, and first detected Tn2009 in ST540. The bla_OXA-23 gene was located on transposons Tn2006 or Tn2009. In addition, the ST540 strain also contains a drug-resistant plasmid with msr(E), armA, sul1 and mph(E) genes.</p><p><strong>Conclusion: </strong>The prevalent clones of Acinetobacter baumannii in our organization have changed during COVID-19, which was different from that of China. ST540 strains which carried multiple drug-resistant mobile elements was spreading, indicating that it is essential to strengthen the molecular epidemiology of Acinetobacter baumannii.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"63"},"PeriodicalIF":4.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11264759/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141722837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pseudonectria keratitis-emerging pathogenic fungi in the eye.","authors":"Yongze Zhu, Peng Nan, Zhongliang Zhu, Youqi Ji, Bingqian Zhuo, Wei Xu, Yumei Ge","doi":"10.1186/s12941-024-00723-1","DOIUrl":"10.1186/s12941-024-00723-1","url":null,"abstract":"<p><strong>Background: </strong>Infectious keratitis, a significant contributor to blindness, with fungal keratitis accounting for nearly half of cases, poses a formidable diagnostic and therapeutic challenge due to its delayed clinical presentation, prolonged culture times, and the limited availability of effective antifungal medications. Furthermore, infections caused by rare fungal strains warrant equal attention in the management of this condition.</p><p><strong>Case presentation: </strong>A case of fungal keratitis was presented, where corneal scraping material culture yielded pink colonies. Lactophenol cotton blue staining revealed distinctive spore formation consistent with the Fusarium species. Further analysis using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) identified the causative agent as Fusarium proliferatum. However, definitive diagnosis of Pseudonectria foliicola infection was confirmed through ITS sequencing. The patient's recovery was achieved with a combination therapy of voriconazole eye drops and itraconazole systemic treatment.</p><p><strong>Conclusion: </strong>Pseudonectria foliicola is a plant pathogenic bacterium that has never been reported in human infections before. Therefore, ophthalmologists should consider Pseudonectria foliicola as a possible cause of fungal keratitis, as early identification and timely treatment can help improve vision in most eyes.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"64"},"PeriodicalIF":4.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11264510/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141722838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fitness costs of Tn1546-type transposons harboring the vanA operon by plasmid type and structural diversity in Enterococcus faecium.","authors":"Dokyun Kim, Da Young Kang, Min Hyuk Choi, Jun Sung Hong, Hyun Soo Kim, Young Ree Kim, Young Ah Kim, Young Uh, Kyeong Seob Shin, Jeong Hwan Shin, Soo Hyun Kim, Jong Hee Shin, Seok Hoon Jeong","doi":"10.1186/s12941-024-00722-2","DOIUrl":"10.1186/s12941-024-00722-2","url":null,"abstract":"<p><strong>Background: </strong>This study analyzed the genetic traits and fitness costs of vancomycin-resistant Enterococcus faecium (VREfm) blood isolates carrying Tn1546-type transposons harboring the vanA operon.</p><p><strong>Methods: </strong>All E. faecium blood isolates were collected from eight general hospitals in South Korea during one-year study period. Antimicrobial susceptibility testing and vanA and vanB PCR were performed. Growth rates of E. faecium isolates were determined. The vanA-positive isolates were subjected to whole genome sequencing and conjugation experiments.</p><p><strong>Results: </strong>Among 308 E. faecium isolates, 132 (42.9%) were positive for vanA. All Tn1546-type transposons harboring the vanA operon located on the plasmids, but on the chromosome in seven isolates. The plasmids harboring the vanA operon were grouped into four types; two types of circular, nonconjugative plasmids (Type A, n = 50; Type B, n = 46), and two types of putative linear, conjugative plasmids (Type C, n = 16; Type D, n = 5). Growth rates of vanA-positive E. faecium isolates were significantly lower than those of vanA-negative isolates (P < 0.001), and reduction in growth rate under vancomycin pressure was significantly larger in isolates harboring putative linear plasmids than in those harboring circular plasmids (P = 0.020).</p><p><strong>Conclusions: </strong>The possession of vanA operon was costly to bacterial hosts in antimicrobial-free environment, which provide evidence for the importance of reducing vancomycin pressure for prevention of VREfm dissemination. Fitness burden to bacterial hosts was varied by type and size of the vanA operon-harboring plasmid.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"62"},"PeriodicalIF":4.6,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11229256/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141557896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Colistin-, cefepime-, and levofloxacin-resistant Salmonella enterica serovars isolated from Egyptian chicken carcasses.","authors":"Bassant Ashraf El-Saeed, Hend Ali Elshebrawy, Amira Ibrahim Zakaria, Adel Abdelkhalek, Khalid Ibrahim Sallam","doi":"10.1186/s12941-024-00713-3","DOIUrl":"10.1186/s12941-024-00713-3","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Objectives: &lt;/strong&gt;The emergence of multidrug-resistant (MDR) Salmonella strains, especially resistant ones toward critically important antimicrobial classes such as fluoroquinolones and third- and fourth-generation cephalosporins, is a growing public health concern. The current study, therefore, aimed to determine the prevalence, and existence of virulence genes (invA, stn, and spvC genes), antimicrobial resistance profiles, and the presence of β-lactamase resistance genes (bla&lt;sub&gt;OXA&lt;/sub&gt;, bla&lt;sub&gt;CTX-M1&lt;/sub&gt;, bla&lt;sub&gt;SHV&lt;/sub&gt;, and bla&lt;sub&gt;TEM&lt;/sub&gt;) in Salmonella strains isolated from native chicken carcasses in Egypt marketed in Mansoura, Egypt, as well as spotlight the risk of isolated MDR, colistin-, cefepime-, and levofloxacin-resistant Salmonella enterica serovars to public health.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;One hundred fifty freshly dressed native chicken carcasses were collected from different poultry shops in Mansoura City, Egypt between July 2022 and November 2022. Salmonella isolation was performed using standard bacteriological techniques, including pre-enrichment in buffered peptone water (BPW), selective enrichment in Rappaport Vassiliadis broth (RVS), and cultivating on the surface of xylose-lysine-desoxycholate (XLD) agar. All suspected Salmonella colonies were subjected to biochemical tests, serological identification using slide agglutination test, and Polymerase Chain Reaction (PCR) targeting the invasion A gene (invA; Salmonella marker gene). Afterward, all molecularly verified isolates were screened for the presence of virulence genes (stn and spvC). The antimicrobial susceptibility testing for isolated Salmonella strains towards the 16 antimicrobial agents tested was analyzed by Kirby-Bauer disc diffusion method, except for colistin, in which the minimum inhibition concentration (MIC) was determined by broth microdilution technique. Furthermore, 82 cefotaxime-resistant Salmonella isolates were tested using multiplex PCR targeting the β-lactamase resistance genes, including bla&lt;sub&gt;OXA&lt;/sub&gt;, bla&lt;sub&gt;CTX-M1&lt;/sub&gt;, bla&lt;sub&gt;SHV&lt;/sub&gt;, and bla&lt;sub&gt;TEM&lt;/sub&gt; genes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Salmonella enterica species were molecularly confirmed via the invA Salmonella marker gene in 18% (27/150) of the freshly dressed native chicken carcasses. Twelve Salmonella serotypes were identified among 129 confirmed Salmonella isolates with the most predominant serotypes were S. Kentucky, S. Enteritidis, S. Typhimurium, and S. Molade with an incidence of 19.4% (25/129), 17.1% (22/129), 17.1% (22/129), and 10.9% (14/129), respectively. All the identified Salmonella isolates (n = 129) were positive for both invA and stn genes, while only 31.8% (41/129) of isolates were positive for the spvC gene. One hundred twenty-one (93.8%) of the 129 Salmonella-verified isolates were resistant to at least three antibiotics. Interestingly, 3.9%, 14.7%, and 75.2% of isolates were categorized into pan-drug-resistant, extensivel","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"61"},"PeriodicalIF":4.6,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11229489/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141533377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potent synergy and sustained bactericidal activity of polymyxins combined with Gram-positive only class of antibiotics versus four Gram-negative bacteria.","authors":"Yan Wang, Jianwen Feng, Jiameng Yu, Lirong Wen, Lidan Chen, Huijie An, Weibin Xiao, Bing Zhang, Huanhuan Feng, Mou Zhou, Zhihui Jiang","doi":"10.1186/s12941-024-00720-4","DOIUrl":"10.1186/s12941-024-00720-4","url":null,"abstract":"<p><strong>Background: </strong>Gram-negative bacteria (GNB) are becoming increasingly resistant to a wide variety of antibiotics. There are currently limited treatments for GNB, and the combination of antibiotics with complementary mechanisms has been reported to be a feasible strategy for treating GNB infection. The inability to cross the GNB outer membrane (OM) is an important reason that a broad spectrum of Gram-positive only class of antibiotics (GPOAs) is lacking. Polymyxins may help GPOAs to permeate by disrupting OM of GNB.</p><p><strong>Objective: </strong>To identify what kind of GPOAs can be aided to broaden their anti-GNB spectrum by polymyxins, we systematically investigated the synergy of eight GPOAs in combination with colistin (COL) and polymyxin B (PMB) against GNB in vitro.</p><p><strong>Methods: </strong>The synergistic effect of COL or PMB and GPOAs combinations against GNB reference strains and clinical isolates were determined by checkerboard tests. The killing kinetics of the combinations were assessed using time-kill assays.</p><p><strong>Results: </strong>In the checkerboard tests, polymyxins-GPOAs combinations exert synergistic effects characterized by species and strain specificity. The synergistic interactions on P. aeruginosa strains are significantly lower than those on strains of A. baumannii, K. pneumoniae and E. coli. Among all the combinations, COL has shown the best synergistic effect in combination with dalbavancin (DAL) or oritavancin (ORI) versus almost all of the strains tested, with FICIs from 0.16 to 0.50 and 0.13 to < 0.28, respectively. In addition, the time-kill assays demonstrated that COL/DAL and COL/ORI had sustained bactericidal activity.</p><p><strong>Conclusions: </strong>Our results indicated that polymyxins could help GPOAs to permeate the OM of specific GNB, thus showed synergistic effects and bactericidal effects in the in vitro assays. In vivo combination studies should be further conducted to validate the results of this study.</p>","PeriodicalId":8052,"journal":{"name":"Annals of Clinical Microbiology and Antimicrobials","volume":"23 1","pages":"60"},"PeriodicalIF":4.6,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11225234/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141533378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}