Current concepts and future strategies in the antimicrobial therapy of emerging Gram-positive spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis(SBP) is the most common infection in end-stage liver disease patients.SBP is defined as an ascitic fluid infection with a polymorphonuclear leucocyte count ≥ 250/mm^3 without an evident intra-abdominal surgically treatable source.Several mechanisms contribute to SBP occurrence,including translocation of gut bacteria and their products,reduced intestinal motility provoking bacterial overgrowth,alteration of the gut's barrier function and local immune responses.Historically,Gram-negative enteric bacteria have been the main causative agents of SBP,thereby guiding the empirical therapeutic choice.However,over the last decade,a worryingly increasing prevalence of Gram-positive and multi-drug resistant(MDR) SBP has been seen.Recently,the microbiological spectrum of SBP seems to have changed in Europe due to a high prevalence of Gram-positive bacteria(48%-62%).The overall proportion of MDR bacteria is up to 22%-73% of cases.Consequently,empirical therapy based on thirdgeneration cephalosporins or amoxicillin/clavulanic acid,can no longer be considered the standard of care,as these drugs are associated with poor outcomes.Theaim of this review is to describe,with an epidemiological focus,the evidence behind this rise in Gram-positive and MDR SBP from 2000 to present,and illustrate potential targeted therapeutic strategies.An appropriate treatment protocol should include daptomycin plus ceftaroline and meropenem,with prompt stepdown to a narrower spectrum when cultures and sensitivity data are available in order to reduce both cost and potential antibiotic resistance development.

Nosocomial spontaneous bacterial peritonitis antibiotic treatment in the era of multi-drug resistance pathogens: A systematic review

To systematically review literature upon aetiology of nosocomial spontaneous bacterial peritonitis (N-SBP) given the rising importance of multidrug-resistant (MDR) bacteria. METHODSA literature search was performed on MEDLINE and Google Scholar databases from 2000 to 15th of November 2016, using the following search strategy: “spontaneous” AND “peritonitis”. RESULTSThe initial search through electronic databases retrieved 2556 records. After removing duplicates, 1958 records remained. One thousand seven hundred and thirty-five of them were excluded on the basis of the screening of titles and abstract, and the ensuing number of remaining articles was 223. Of these records, after careful evaluation, only 9 were included in the qualitative analysis. The overall proportion of MDR bacteria turned out to be from 22% to 73% of cases across the studies. CONCLUSIONN-SBP is caused, in a remarkable proportion, by MDR pathogens. This should prompt a careful re-assessment of guidelines addressing the treatment of this clinical entity.

Extensively drug-resistant bacteria are an independent predictive factor of mortality in 130 patients with spontaneous bacterial peritonitis or spontaneous bacteremia

AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis.METHODS: We prospectively collected clinical, laboratory characteristics, type of administered antibiotic, susceptibility and resistance of bacteria to antibiotics in one hundred thirty cases (68.5% males) with positive ascitic fluid and/or blood cultures during the period from January 1, 2012 to May 30, 2014. All patients with SBP had polymorphonuclear cell count in ascitic fluid > 250/mm3. In patients with SB a thorough study did not reveal any other cause of bacteremia. The patients were followed-up for a 30-d period following diagnosis of the infection. The final outcome of the patients was recorded in the end of follow-up and comparison among 3 groups of patients according to the pattern of drug resistance was performed.RESULTS: Gram-positive-cocci (GPC) were found in half of the cases. The most prevalent organisms in a descending order were Escherichia coli (33), Enterococcus spp (30), Streptococcus spp (25), Klebsiella pneumonia (16), S. aureus (8), Pseudomanas aeruginosa (5), other Gram-negative-bacteria (GNB) (11) and anaerobes (2). Overall, 20.8% of isolates were multidrug-resistant (MDR) and 10% extensively drug-resistant (XDR). Health-care-associated (HCA) and/or nosocomial infections were present in 100% of MDR/XDR and in 65.5% of non-DR cases. Meropenem was the empirically prescribed antibiotic in HCA/nosocomial infections showing a drug-resistance rate of 30.7% while third generation cephalosporins of 43.8%. Meropenem was ineffective on both XDR bacteria and Enterococcus faecium (E. faecium). All but one XDR were susceptible to colistin while all GPC (including E. faecium) and the 86% of GNB to tigecycline. Overall 30-d mortality was 37.7% (69.2% for XDR and 34.2% for the rest of the patients) (log rank, P = 0.015). In multivariate analysis, factors adversely affecting outcome included XDR infection (HR = 2.263, 95%CI: 1.005-5.095, P = 0.049), creatinine (HR = 1.125, 95%CI: 1.024-1.236, P = 0.015) and INR (HR =1.553, 95%CI: 1.106-2.180, P = 0.011).CONCLUSION: XDR bacteria are an independent life-threatening factor in SBP/SB. Strategies aiming at restricting antibiotic overuse and rapid identification of the responsible bacteria could help improve survival.

Bacterial infection after liver transplantation

Infectious complications are major causes of morbidity and mortality after liver transplantation,despite recent advances in the transplant field.Bacteria,fungi,viruses and parasites can cause infection before and after transplantation.Among them,bacterial infections are predominant during the first two months posttransplantation and affect patient and graft survival.They might cause surgical site infections,including deep intra-abdominal infections,bacteremia,pneumonia,catheter-related infections and urinary tract infections.The risk factors for bacterial infections differ between the periods after transplant,and between centers.Recently,the emergence of multi-drug resistant bacteria is great concern in liver transplant(LT)patients.The instructive data about effects of infections with extended-spectrum beta lactamase producing bacteria,carbapenem-resistant gram-negative bacteria,and glycopeptide-resistant gram-positive bacteria were reported on a center-by-center basis.To prevent posttransplant bacterial infections,proper strategies need to be established based upon center-specific data and evidence from well-controlled studies.This article reviewed the recent epidemiological data,risk factors for each type of infections and important clinical issues in bacterial infection after LT.

Bacterial contamination of orally-consumed crude herbal remedies:A potential source for multi-drug resistant pathogens in man

Objective:The acceptability of herbal remedies for alleviating discomforts and ill-health has become very popular, on the account of the increasing cost of allopathic medicine for personal health maintenance.The observable non-adherence of herbalists to the established World Health Organization(WHO) / National Agency for Food and Drug Administration Control(NAFDAC) regulations for the quality control of herbal medicines is an issue for concern.In view of this,34 popular and widely consumed crude herbal remedies in southwestern,Nigeria were screened for compliance with standard limits for bacterial contamination,bacteria flora and their antibiotic susceptibility pattern.Methods:Isolates recovered from samples were identified using the cultural, morphological and biochemical characteristics.They were also tested for drug sensitivity using standard procedures. Results:A heavy bacteria load ranging from 3.00×10~3-9.58×10~5 CFU/ML and 1.20×10~5- 5.41×10~5 CFU/ML was observed for water and spirit extracted preparations respectively.The bacteria flora cum contaminants were:Staphylococcus aureus,Bacillus cereus,Bacillus subtilis,Pseudomonas aeruginosa, Micrococcus luteus,Lactobacillus plantarum,Klebsiella pneumoniae,Escherichia coli,streptococcus,Shigella, Neisseria,Arthrobacter,Kurthia and Clostridium species.All the isolates were multi-drug resistant(MDR) strains.Conclusion:The crude herbal preparations consumed in Nigeria failed to comply with the internationally recognized standards regarding bacteria load and flora.The presence of MDR pathogens is of greatest concern. It poses a great risk to consumers health and could be a source of introducing MDR organisms into the human population.There is the need for the enforcement of established guidelines to ensure the safety of these preparations.

Unresolved issues in the prophylaxis of bacterial infections in patients with cirrhosis

Bacterial infections are highly prevalent and a frequent cause of hospitalization and short-term mortality in patients with cirrhosis. Due to their negative impact on survival, antibiotic prophylaxis for bacterial infections in high-risk subgroups of patients with cirrhosis has been the standard of care for decades. Patients with prophylaxis indications include those at risk for a first episode of spontaneous bacterial peritonitis(SBP) due to a low ascitic fluid protein count and impaired liver and kidney function, patients with a prior episode of SBP and those with an episode of gastrointestinal bleeding. Only prophylaxis due to gastrointestinal bleeding has a known and short-time duration. All other indications imply longlasting exposure to antibiotics-once the threshold requirement for initiating prophylaxis is met-without standardized criteria for re-assessing antibiotic interruption. Despite the fact that the benefit of antibiotic prophylaxis in reducing bacterial infections episodes and mortality has been thoroughly reported, the extended use of antibiotics in patients with cirrhosis has also had negative consequences, including the emergence of multi-drug resistant bacteria.Currently, it is not clear whether restricting the use of broad and fixed antibiotic regimens, tailoring the choice of antibiotics to local bacterial epidemiology or selecting non-antibiotic strategies will be the preferred antibiotic prophylaxis strategy for patients with cirrhosis in the future.

Epidemiological Characteristics, Resistance Patterns and Spread of Gram-Negative Bacteria Related to Colonization of Patients in Intensive Care Units

Our aim was to determine the epidemiological characteristics, the resistance patterns and the spread of Gram negative bacteria related to colonization of patients in adult Intensive Care Units. Methods: A prospective cohort of patients colonized and/or infected with Gram negative bacteria was conducted at two adult ICUs from hospitals in Brazil (April 2012 to February 2013). Nasal, groin and perineum swabs were performed. Samples were incubated on MacConkey and cetrimide agar (48 h at 37℃) and identification tests (Vitek-BioMérieux), antibiogram (Bauer-Kirby method), Carba NP test, Polymerase Chain Reaction (PCR) and sequencing were performed. The patterns of resistant microorganisms were compared by rep-PCR (Diversilab). Results: There were 53 cases of colonization. In these cases, we identified imipenem-resistant Acinetobacter baumannii (51%), Pseudomonas aeruginosa (32%), Klebsiella pneumoniae ESBL (38%) or imipenem resistant (5.6%). The use of antimicrobials and medical devices were related to colonization (p The resistance patterns expressed by Klebsiella pneumoniae were ESBL (CTX-M, SHV e TEM) and KPC2. A verified profile of Acinetobacter baumannii was related to OXA-23 and OXA-253 (OXA-143 variant). The profiles ESBL and KPC2 expressed by Klebsiella pneumoniae were distributed between the both ICUs. The distribution of OXA-23 and OXA-253 was verified only in one ICU. The similarity of strains ranged from 80% to 95%, highlighting the horizontal transference of these microorganisms.

Distribution and drug resistance of pathogenic bacteria isolated from cancer hospital in 2013

Objective： To understand distribution and drug resistance of pathogenic bacteria from a specialized cancer hospital in 2013 in order to provide a basis for rational clinical antimicrobial agents. Methods： Pathogenic bacteria identification and drug sensitivity tests were performed with a VITEK 2 compact automatic identification system and data were analyzed using WHONET5.6 software.Results： Of the 1,378 strains tested, 980 were Gram-negative bacilli, accounting for 71.1%, in which Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa were the dominant strains. We found 328 Gram-positive coccus, accounting for 23.8%, in which the amount of Staphylococcus aureus was the highest. We identified 46 fungi, accounting for 4.1%. According to the departmental distribution within the hospital, the surgical departments isolated the major strains, accounting for 49.7%. According to disease types, lung cancer, intestinal cancer and esophagus cancer were the top three, accounting for 20.9%, 17.3% and 14.2%, respectively. No strains were resistant to imipenem, ertapenem or vancomycin.Conclusions： Pathogenic bacteria isolated from the specialized cancer hospital have different resistance rates compared to commonly used antimicrobial agents; therefore antimicrobial agents to reduce the morbidity and mortality of infections should be used.

Screening of Antagonistic Bacteria against Phytophthora infestans and Its Inhibition Effect

[ Objective ] The paper was to screen bacterial strain with significant antagonistic effect against Phytophthora infestans, so as to provide basis for further development and utilization of antagonistic bacteria to inhibit P. infestans and control potato late bright. [ Method] Plate dual culture and filter paper method were used to determine the inhibition effect of strains in vivo, fermentation broth and bacterial liquid of 61 strains against P. infestans and the resistance-induction effect of SR13-2 strain. [ Result] The inhibition rate of 24 strains among 61 tested strains against mycelial growth of P. infestans was greater than 60%, and the inhibi- tion effect of HT-6 strain was the strongest with the inhibition rate of 89.92%. However, fermentation broth of all tested strains had no significant inhibition effect against P. infestans, while the inhibition effect of bacterial liquid of most strains was significantly higher than strain in vivo; the inhibition effect of $34-1 strain was the strongest with inhibition rate of 91.50%. The bacterial liquid of SR13-2 strain was found to have significant resistance-induction effect with protective rate of 60%. [ Conclusion] The inhibition effect of strains in vivo and fermentation broth of antagonistic strains S34-1 and SR13-2 had no relationship with each other, while bacterial liquid had great application potential in controlling potato late bright.

Sensitivity of Planktonic Aquatic Bacteria to Ciprofloxacin

Many anthropogenic compounds, such as antibiotics, are found at trace levels (-1) in aquatic and terrestrial systems. The effect of these compounds on the metabolism and function of microbes are difficult to assess because the assays used, such as the minimum inhibitory concentration (MIC) and the disk diffusion methods, lack the sensitivities to measure bacterial response to these very low levels of antibiotics on bacterial populations. Therefore, we theorized that the [3H] thymidine incorporation into DNA method might be sensitive in determining the effect of DNA inhibiting antibiotics on DNA production in planktonic bacteria in aquatic systems. Utilizing the 3H thymidine method, we measured the effects of ciprofloxacin on DNA production on planktonic bacteria in river and pond waters. Ciprofloxacin significantly (P < 0.02) inhibited river water bacteria at a concentration of 25 μg·L-1 but significant inhibition (P < 0.01) occurred at 1000 μg·L-1in pond water. The very low concentration required to inhibit DNA production in river water bacteria indicates that bacteria are extremely sensitive to antibiotics at very low concentrations. A likely reason for the differences in inhibition between the two waters is due to ciprofloxacin becoming bound, and possibly becoming biologically inactive, in the pond water due to higher dissolved organic carbon content. This work demonstrates that bacteria in some aquatic systems can be significantly impacted by low concentrations of anthropogenic antibiotics finding their way into these systems and that our assumptions as to the concentrations at which antibiotics affect microbes are highly underestimated.

2020—2022年自贡市第一人民医院细菌耐药性监测

目的了解自贡市第一人民医院临床分离菌对抗菌药物的耐药性,为临床合理使用抗菌药物提供依据。方法收集我院2020—2022年临床分离菌株,采用VITEK自动化鉴定及药敏系统、纸片扩散法及E-test方法进行细菌鉴定及药物敏感试验,以2022年美国临床和实验室标准化协会(CLSI)折点标准判断结果。结果共分离出临床菌株13324株,其中革兰阴性菌占69.6%,革兰阳性菌占30.4%。前五位分离菌为大肠埃希菌、肺炎克雷伯菌、金黄色葡萄球菌、铜绿假单胞菌和流感嗜血杆菌。耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的检出率分别为24.1%和73.0%。耐利奈唑胺屎肠球菌和粪肠球菌的检出率分别为2.1%和12.4%,分离出1株耐万古霉素的屎肠球菌。脑脊液中分离的4株肺炎链球菌均为青霉素非敏感菌株,未检出非脑脊液来源耐青霉素肺炎链球菌。耐碳青霉烯类阴沟肠杆菌的检出率为12.3%。而耐碳青霉烯类大肠埃希菌和肺炎克雷伯菌检出率低,分别为1.1%和2.9%。铜绿假单胞菌对哌拉西林/他唑巴坦、头孢吡肟和庆大霉素的耐药率逐年增加;鲍曼不动杆菌对常见抗菌药物耐药率明显高于铜绿假单胞菌,耐碳青霉烯类菌株检出率分别为41.9%和6.9%。未分离出耐头孢噻肟的流感嗜血杆菌和卡他莫拉菌。结论临床分离菌以革兰阴性菌为主,常见分离菌的耐药率呈现平稳或略有降低的特点。然而,耐利奈唑胺粪肠球菌和耐阿莫西林/克拉维酸流感嗜血杆菌检出率明显升高,应加强医院感染防控措施和抗菌药物的合理使用。

急性髓系白血病合并血流感染的病原菌分布与耐药性变迁及患者死亡的危险因素分析

目的探讨成人急性髓系白血病(AML)合并血流感染的病原菌分布与耐药性变迁,并分析患者死亡的危险因素。方法比较85例AML合并血流感染确诊时间的前30个月(2017年1月—2019年6月检出的病原菌)和后30个月(2019年7月—2021年12月)的病原菌检出率和主要病原菌耐药率变迁情况。并按患者血流感染后6个月预后分为死亡组33例和生存组52例。采用Logistic回归分析影响AML合并血流感染患者死亡的危险因素。结果85例AML合并血流感染患者共检出98株病原菌,以革兰阴性菌为主(65/98,66.33%),其次为革兰阳性菌(29/98,29.59%)、真菌(4/98,4.08%)。后30个月检出真菌(均为念珠菌)比例较前30个月增多(P<0.05)。后30个月与前30个月检出革兰阴性菌、革兰阳性菌比例及大肠埃希菌、金黄色葡萄球菌耐药率比较差异均无统计学意义(P>0.05)。Logistic回归分析显示,确诊前1个月内抗生素使用史、感染性休克为AML合并血流感染患者死亡的独立危险因素(P<0.05)。结论成人AML合并血流感染的病原菌以革兰阴性菌为主,但近年念珠菌感染率升高,且血流感染前使用抗生素及并发感染性休克者易出现预后不良。

2020—2022年某医院主要细菌耐药情况分析

目的通过分析福建中医药大学附属第二人民医院2020年1月—2022年12月常见细菌的耐药性,了解医院的细菌耐药情况,为临床提供合理使用抗菌药物的参考依据。方法通过回顾性分析方法对2020年1月—2022年12月福建中医药大学附属第二人民医院患者标本分离的病原菌株进行统计,从病原菌标本分布、病原菌种类及耐药等方面进行分析。结果2020—2022年分离的菌株共计12009株,呼吸道标本(包括痰、肺泡灌洗液)最多。前5位为大肠埃希菌2139株(17.81%)、肺炎克雷伯菌1342株(11.17%)、铜绿假单胞菌1094株(9.11%)、金黄色葡萄球菌为主793株(6.60%)、鲍曼不动杆菌541株(4.50%)。耐碳青霉烯类肺炎克雷伯菌(Carbapenemresistant K.pneumoniae,CR-KP)和耐碳青霉烯类铜绿假单胞菌(Carbapenemresistant Pseudomonas aeruginosa,CR-PA)2022年比2020年明显升高,差异有统计学意义(P<0.01)。其余3种耐甲氧西林金黄色葡萄球菌(Methicillin-resistant S.aureus,MRSA)、耐碳青霉烯类大肠埃希菌(Carbapenemresistant Escherichia coli,CR-EC)、耐碳青霉烯类鲍曼不动杆菌(Carbapenemresistant Acinetobacter baumannii,CRAB)3年间检出率差异无统计学意义(P>0.05)。鲍曼不动杆菌对大多数常用抗菌药物耐药率>50%。结论福建中医药大学附属第二人民医院主要以革兰阴性杆菌为主,鲍曼不动杆菌对大多数常用抗菌药物耐药率>50%,CR-KP(耐碳青霉烯类肺炎克雷伯菌)和CR-PA(耐碳青霉烯类铜绿假单胞菌)的耐药率呈增高趋势,建议临床密切关注病原菌耐药情况的变化,减少多重耐药菌的产生。

细菌性脑膜炎症候群患儿菌群情况及其耐药分析

目的调查研究细菌性脑膜炎症候群患儿菌群情况以及耐药情况。方法选择199例细菌性脑膜炎症候群患儿为研究对象,采集所有患儿的脑脊液标本完成细菌培养以及药敏试验。分析病原菌分布情况及主要病原菌耐药特点。结果199例患儿脑脊液共检出病原菌61株,按照占比从高到低的顺序分别为肺炎链球菌、无乳链球菌、大肠埃希菌、金黄色葡萄球菌、凝固酶阴性葡萄球菌、屎肠球菌、白色念球菌、脑膜炎奈瑟菌及其他,占比分别为31.15%、21.31%、19.67%、16.39%、3.28%、3.28%、1.64%、1.64%、1.64%。大肠埃希菌对亚胺培南以及美罗培南的耐药性均为0,对其他抗菌药物均有不同程度的耐药性;脑膜炎奈瑟菌对亚胺培南、美罗培南、头孢曲松以及头孢噻肟耐药性均为0,对其他抗菌药物均有不同程度的耐药性。肺炎链球菌对万古霉素的耐药性均为0,对其他抗菌药物均有不同程度的耐药性;无乳链球菌对头孢哌酮的耐药性为0,对环丙沙星的耐药率为7.69%,而对其他抗菌药物均有明显耐药性;金黄色葡萄球菌对万古霉素以及利奈唑胺的耐药性均为0,对其他抗菌药物均有不同程度耐药性;凝固酶阴性葡萄球菌对万古霉素以及利奈唑胺的耐药性均为0,对其他抗菌药物均有不同程度耐药。结论细菌性脑膜炎症候群患儿致病菌以肺炎链球菌、无乳链球菌、大肠埃希菌、金黄色葡萄球菌、凝固酶阴性葡萄球菌以及脑膜炎奈瑟菌为主,且不同致病菌对不同抗菌药物的耐药性不同,临床工作中应根据药敏试验结果合理选用抗菌药物。

无菌体液分离病原菌菌种构成分布情况及耐药性变迁

目的了解2017—2023年本院无菌体液标本检出病原菌的分布及其耐药性变迁,为本地区医疗机构经验使用抗菌药物提供及时依据。方法选取2017—2023年本院无菌体液标本,排除同一患者重复株,使用WHONET 5.6软件对药物敏感性数据进行统计分析。结果共检出菌株6711株,其中革兰阴性杆菌3927株,革兰阳性球菌2530株,真菌145株,厌氧菌59株。分离病原菌前五位依次为大肠埃希菌、凝固酶阴性葡萄球菌、肺炎克雷伯菌、金黄色葡萄球菌、铜绿假单胞菌。肠杆菌目细菌中,大肠埃希菌和阴沟肠杆菌对常用抗菌药物的耐药性较稳定,肺炎克雷伯菌对抗菌药物的耐药性明显升高。大肠埃希菌和肺炎克雷伯菌对碳青霉烯类耐药率平均为1.2%和12.8%。铜绿假单胞菌对常用抗菌药物的耐药率较低且有降低趋势,鲍曼不动杆菌对常用抗菌药物的耐药率较高且稳定。甲氧西林耐药金黄色葡萄球菌(MRSA)和甲氧西林耐药凝固酶阴性葡萄球菌(MRCNS)的检出率分别为31.2%和71.4%,两者对常用抗菌药物的耐药性较稳定,MRSA的检出率有一定程度的降低。屎肠球菌和粪肠球菌对万古霉素和利奈唑胺均保持高度活性,对常用抗菌药物的耐药性较稳定。结论2017—2023年本院无菌体液病原菌以革兰阴性杆菌为主。及时监测病原菌种类、分布和耐药情况以指导临床合理用药,可有效减缓细菌耐药性的产生。

2018年-2021年南阳市医院抗菌药物使用情况与常见细菌耐药性相关性分析

目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性杆菌、阳性球菌对抗菌药物产生的耐药率(%)与抗菌药物用药频度(Frequency of defined daily doses,DDDs)的相关性。结果:我院2018年至2021年抗菌药物DDDs较高的抗菌药物依次为美洛西林、头孢他啶、哌拉西林他唑巴坦,检出率较高的病原菌分别为大肠埃希氏菌、肺炎克雷伯菌、金黄色葡萄球菌等。大肠埃希菌产生的耐药率与哌拉西林他唑巴坦、头孢呋辛钠DDDs均有相关性(r=-0.107、0.432);肺炎克雷伯菌产生的耐药率与哌拉西林他唑巴坦、左氧氟沙星氯化钠、头孢呋辛钠DDDs呈正相关(r=0.410、0.720、0.420);铜绿假单胞菌与哌拉西林他唑巴坦、头孢哌酮舒巴坦钠DDDs呈正相关(r=0.716、0.933);金黄色葡萄球菌的耐药率与左氧氟沙星DDDs呈正相关(r=0.661);肺炎链球菌产生的耐药率与左氧氟沙星、头孢呋辛钠DDDs均存在正相关关系(r=0.416和0.482)。结论:抗菌药物的DDDs与常见细菌产生的耐药性具有一定的相关性,我院应严格控制抗菌药物的DDDs,根据感染性病种及药敏试验结果选择适当的抗菌药,加强常见病原菌的耐药监测。

除臭菌的筛选及其在堆肥中的应用效果

【目的】筛选新型除臭菌,解决以鸡粪为主要原料的有机肥厂的臭气排放问题,为好氧堆肥生物除臭技术提供理论依据和支撑。【方法】以鸡粪为筛菌样品,利用定性初筛、驯化富集、分离纯化、定量复筛、拮抗试验以及耐药性试验筛选能够满足多重目标的除臭菌,并通过形态观察与16S rDNA测序鉴定菌株。将筛选获得的除臭菌株制成复合菌剂BH并应用于鸡粪堆肥,共设置3个处理,分别为对照CK(原料中不添加菌剂)、DT1(原料中添加1%除臭菌剂BH)、DT2(原料中添加1%的市售商品除臭菌剂)。在堆肥不同时期,分析测定堆体温度、pH、电导率(EC)、庆大霉素(GM)含量以及NH3排放量等指标,探讨耐药性除臭菌剂BH对堆肥过程的影响。【结果】初步筛选分离获得15株细菌,命名为BH1—BH15,未筛选到真菌;经复筛发现,菌株BH2、BH5、BH9、BH11、BH12和BH15对NH3的去除率较高,分别为48.8%、49.4%、45.8%、48.3%、51.0%和51.8%,且各菌株间无拮抗作用。对除臭菌株耐药性研究发现,菌株BH11和BH12对庆大霉素具有较强的耐受性;经形态学特征与分子生物学鉴定,菌株BH11为Bordetella sp.,BH12为Weeksella massiliensis。将菌株BH11和BH12制成复合菌剂BH,其除臭效果显著优于单一菌剂,NH3去除率高达65.8%。堆肥试验中,各处理高温期均持续9 d以上,实现了鸡粪的无害化处理;堆肥结束时各处理的pH稳定在8.4左右,处于5.5—8.5之间,EC在2.73—3.43 mS·cm^(-1)之间,低于4 mS·cm^(-1),表明物料可用作植物肥料且符合有机肥标准。研究发现,DT2处理的GM降解效率显著高于CK处理,表明商品菌剂能够促进庆大霉素降解。此外,堆肥过程中NH3的排放主要发生在堆肥升温期与高温期,且高温期的排放量高于升温期;与CK处理相比,菌剂BH显著抑制升温期NH3的排放,且除臭效果优于商品菌剂;而进入高温期后,商品菌剂除臭效果优于菌剂BH。【结论】筛选获得2株耐药性除臭菌,对NH3的去除率分别为48.3%(BH11)和51.0%(BH12),制成的复合菌剂BH对NH3的去除率高达65.8%。将菌剂BH应用于鸡粪堆肥,可以有效减少堆肥过程中NH3的排放,且各指标均符合堆肥腐熟标准。

耐药菌的环境分布、传播及新型抗菌技术研究进展

抗生素的广泛使用导致细菌耐药性增加、多重耐药菌菌群数量急剧增多,严重威胁着人类生命健康.环境中耐药菌(ARB)及耐药基因(ARGs)的存在给临床治疗耐药菌感染带来了巨大挑战.有关医院中常见耐药致病菌的研究已有很多,尚缺乏环境中耐药菌的分布、传播及新型耐药菌抗菌技术等的相关研究.本文综述了耐药菌的环境分布特征及其传播机制,概述了新型抗菌技术及其应用,最后展望了有关环境耐药菌研究的未来发展方向.

漂白粉消毒后对虾养殖源水细菌群落的响应特征研究

漂白粉消毒是凡纳滨对虾养殖源水常见的管控措施,可有效控制病原菌传播;然而,消毒会强烈扰动水体微生物群落,但源水细菌群落对漂白粉消毒的响应特征尚未阐明。在室内条件下,设置高浓度(60 mg/L)和低浓度(20 mg/L)漂白粉消毒源水,通过高通量测序及荧光定量PCR技术探究消毒后源水细菌群落、病原菌及抗生素抗性基因(ARGs)的动态响应规律。结果显示,消毒后,拟杆菌门(Bacteroidota)丰度上升,高浓度组变形菌门(Proteobacteria)的丰度显著降低;至第3天,两组源水的细菌群落组成趋于一致。此外,漂白粉消毒显著改变了源水的细菌群落结构及共现网络的复杂性。在控制水体病原菌方面,消毒后病原菌的总丰度降低,但种类增加,高浓度漂白粉消毒对病原菌的抑制作用更加显著。漂白粉消毒对ARGs的去除具有选择性,仅对sul1、floR、cfr、tetQ有一定的去除作用,且高、低浓度对ARGs的去除无差异。综上,60 mg/L可以作为漂白粉消毒养殖源水的更好浓度选择。研究结果从微生物生态视角评价了不同浓度漂白粉的消毒作用,可为对虾养殖生产中的源水管控提供理论支撑。

2017—2022年山东地区不同人群脓液标本病原谱及耐药性变迁分析

目的监测山东地区2017—2022年不同年龄段患者脓液标本病原谱的构成和耐药性及药物敏感性情况,为外科医生早期经验性抗微生物治疗提供参考依据。方法回顾分析山东地区2017—2022年间山东省儿童细菌耐药监测研究协作网(Shandong Province Pediatric Antimicrobial Resistance Surveillance System,SPARSS)成员单位上报的脓液标本分离菌株的临床信息及药物敏感性结果。结果共分离病原菌64302株,新生儿脓液分离的细菌以革兰阳性菌为主,儿童和成人脓液分离的细菌以革兰阴性菌为主。对年龄分层分布发现,新生儿组病原菌分离最多的是金黄色葡萄球菌,儿童组和成人组脓液病原菌分离最多的是大肠埃希菌,3组的菌种分布有较大差异(χ2=245.5,P<0.0001)。肠杆菌科中大肠埃希菌和肺炎克雷伯菌耐药率较严重,产超广谱β-内酰胺酶(extended spectrumβ-lactamases,ESBLs)和对碳青霉烯类耐药的大肠埃希菌占比分别为41.8%和0.83%;肺炎克雷伯菌占比分别为14.1%和1.14%。铜绿假单胞菌对大多数抗生素成人组耐药率明显高于儿童组。葡萄球菌属中耐甲氧西林金黄色葡萄球菌(MRSA)检出率为22.6%且在2017—2022年呈下降趋势,其中新生儿MRSA占比显著高于儿童和成人(χ2=12.32,P=0.0021)。结论脓液感染病原菌以大肠埃希菌、金黄色葡萄球菌、肺炎克雷伯菌和铜绿假单胞菌为主,不同年龄组的病原谱构成有较大差异,主要分离菌种对抗微生物药物的耐药率较高,故应定期监测脓液来源病原谱及耐药性变迁规律,以提高外科医生感染性疾病的精准诊治能力。