Antimicrobial susceptibility testing for Helicobacter pylori in times of increasing antibiotic resistance

The gram-negative bacterium Helicobacter pylori(H.pylori)causes chronic gastritis,gastric and duodenal ulcers,gastric cancer and mucosa-associated lymphoid tissue lymphoma.Treatment is recommended in all symptomatic patients.The current treatment options for H.pylori infection are outlined in this review in light of the recent challenges in eradication success,largely due to the rapid emergence of antibiotic resistant strains of H.pylori.Antibiotic resistance is a constantly evolving process and numerous studies have shown that the prevalence of H.pylori antibiotic resistance varies significantly from country to country,and even between regions within the same country.In addition,recent data has shown that previous antibiotic use is associated with harbouring antibiotic resistant H.pylori.Local surveillance of antibiotic resistance is warranted to guide clinicians in their choice of therapy.Antimicrobial resistance is assessed by H.pylori culture and antimicrobial susceptibility testing.Recently developed molecular tests offer an attractive alternative to culture and allow for the rapid molecular genetic identification of H.pylori and resistance-associated mutations directly from biopsy samples or bacterial culture material.Accumulating evidence indicates that surveillance of antimicrobial resistance by susceptibility testing is feasible and necessary to inform clinicians in their choice of therapy for management of H.pylori infection.

A comparative study on antimicrobial susceptibility of uroculturome of humans in health and urinary tract infections

Background:The uroculturome indicates the profile of culturable microbes inhabiting the urinary tract,and it is often required to do a urine culture to find an effective antimicrobial to treat urinary tract infections(UTIs).Methods:This study targeted to understand the profile of culturable pathogens in the urine of apparently healthy(128)and humans with clinical UTIs(161)and their antimicrobial susceptibility.All the urine samples were analyzed to quantify microbial load and determine the diversity and antimicrobial susceptibility of microbes following standard microbiological methods.Results:In urine samples from UTI cases,microbial counts were 1.2×10^(4)±6.02×10^(3) colony-forming units(cfu)/mL,while in urine samples from apparently healthy humans,the average count was 3.33±1.34×10^(3) cfu/mL.In eight samples(six from UTI cases and two from apparently healthy people,Candida(C.albicans 3,C.catenulata 1,C.krusei 1,C.tropicalis 1,C.parapsiplosis 1,C.gulliermondii 1)and Rhizopus species(1)were detected.Candida krusei was detected only in a single urine sample from a healthy person and C.albicans was detected both in urine of healthy and clinical UTI cases.Gram-positive(G+ve)bacteria were more commonly(Odds ratio,1.98;CI99,1.01-3.87)detected in urine samples of apparently healthy humans,and Gram-negative(G−ve)bacteria(Odds ratio,2.74;CI99,1.44-5.23)in urines of UTI cases.From urine samples of 161 UTI cases,a total of 90 different types of microbes were detected and,73 samples had only a single type of bacteria.In contrast,49,29,3,4,1,and 2 samples had 2,3,4,5,6 and 7 types of bacteria,respectively.The most common bacteria detected in urine of UTI cases was Escherichia coli(52 samples),in 20 cases as the single type of bacteria,other 34 types of bacteria were detected in pure form in 53 cases.From 128 urine samples of apparently healthy people,88 types of microbes were detected either singly or in association with others,from 64 urine samples only a single type of bacteria was detected while 34,13,3,11,2 and 1 sample yielded 2,3,4,5,6 and seven types of microbes,respectively.In the urine of apparently healthy humans too,E.coli was the most common bacteria,(10 samples)followed by Staphylococcus haemolyticus(9),S.intermedius(5),and S.aureus(5),and similar types of bacteria also dominated in cases of mixed occurrence,E.coli was detected in 26,S.aureus in 22 and S.haemolyticus in 19 urine samples,respectively.G+ve bacteria isolated from urine samples’irrespective of health status were more often(P<0.01)resistant than G−ve bacteria to ajowan oil,holy basil oil,cinnamaldehyde,and cinnamon oil,but more susceptible to sandalwood oil(P<0.01).However,for antibiotics,G+ve were more often susceptible than G−ve bacteria to cephalosporins,doxycycline,and nitrofurantoin.Conclusion:The study concludes that to understand the role of good and bad bacteria in the urinary tract microbiome more targeted studies are needed to discern the isolates at the pathotype level.Further,the study suggests the use of antibiotics by observing good antibiotic stewardship following antibiotic susceptibility testing only.

Importance of antimicrobial susceptibility testing for the management of eradication in Helicobacter pylori infection

The management of Helicobacter pylori(H. pylori) infection treatment differs from the common treatment protocol for other infectious diseases. Because culture-or molecular-guided approaches face several practical issues, such as the invasive procedures required to obtain gastric biopsy specimens and the lack of availability of routine laboratory testing in some places, H. pylori treatment includes the administration of two or three empirically selected antibiotics combined with a proton pump inhibitor rather than evidence-based eradication treatment. The efficacy of empirical therapy is decreasing, mostly due to increasing multiple resistance. Multiresistance to levofloxacin, clarithromycin, and metronidazole, which are commonly used in empirical treatments, appears to have increased in many countries. Mutations play a primary role in the antimicrobial resistance of H. pylori, but many different mechanisms can be involved in the development of antibiotic resistance. Determining and understanding these possible mechanisms might allow the development of new methods for the detection of H. pylori and the determination of antimicrobial resistance. A treatment based on the detection of antimicrobial resistance is usually more effective than empirical treatment. Nevertheless, such an approach before treatment is still not recommended in the Maastricht guidelines due to the difficulty associated with the routine application of available cultureor molecular-based susceptibility tests, which are usually administered in cases of treatment failure. The management of first and rescue treatments requires further research due to the steadily increase in antimicrobial resistance.

Prevalence and antimicrobial resistance pattern of bacterial strains isolated from patients with urinary tract infection in Messalata Central Hospital, Libya

Objective: To investigate the prevalence of urinary tract infection among patients at Messalata Central Hospital, Libya, to identify the causative bacteria, and to explore their resistance pattern to antimicrobials. Methods: A total number of 1 153 urine samples were collected from patients, who attended daily to Messalata Central Hospital, Libya, in a study extended for one year. Antimicrobial susceptibility testing and isolates typing were done using Phoenix BD(BD diagnostic). Resistance was confirmed manually using agar disk diffusion method. Results: Of the 1 153 urine samples tested, 160(13.9%) samples were positive, from which 17 different, solely Gram negative, uropathogens were identified. Escherichia coli were the most prevalent(55.6%) bacteria, followed by Klebsiella pneumoniae subspecies pneumoniae(16.3%), Proteus mirabilis(6.3%), Pseudomonas aeruginosa(5.6%), Enterobacter cloacae and Klebsiella oxytoca(2.5%, each), Citrobacter koseri and Providencia rettgeri(1.9%, each), Acinetobacter baumannii, Enterobacter aerogenes and Proteus vulgaris(1.3%, each), and Aeromonas caviae, Citrobacter freundii, Cronobacter sakazakii, Enterobacter amnigenus biogroup 2, Pseudomonas putida and Serratia marcescens(0.6%, each). The isolated uropathogens showed increased levels of resistance ranged from 10.5% to 64.5%, with an overall resistance of 28.9%. Amikacin was the most effective antimicrobial followed by Imipenem and Meropenem(0%, 0.6% and 2.5% resistance, respectively); while, Cephalothin and Ampicillin were the least(80.6% and 90.0% resistance, respectively) effective. Conclusions: The obtained results emphasized the emergence of highly resistant bacteria to most of tested antimicrobials and raise the alarm for physicians to change their treatment pattern depending on antimicrobial susceptibility results.

Analysis on Antimicrobial Resistance of Clinical Bacteria Isolated from County Hospitals and a Teaching Hospital

The distinction of antimicrobial resistance of clinical bacteria isolated from county hospitals and a teaching hospital was investigated. Disc diffusion test was used to study the antimicrobial resistance of isolates collected from county hospitals and a teaching hospital. The data was analyzed by WHONET5 and SPSS statistic software. A total of 655 strains and 1682 strains were collected from county hospitals and a teaching hospital, respectively, in the year of 2003. The top ten pathogens were Coagulase negative staphylococci （CNS）, E. coil, Klebsiella spp. , S. areus, P. aeruginosa, Enterococcus spp. , Enterobacter spp. , otherwise Salmonella spp. , Proteus spp. , Shigella spp. in county hospitals and Streptococcus spp. , Acinetobacter spp. , X. maltophilia in the teaching hospital. The prevalence of multi-drug resistant bacteria was 5 % （4/86） of methicillin-resistant S. areus （MRSA）, 12 % （16/133） and 15.8 % （9/57） of extended-spectrum β-lactamases producing strains of E. coil and Klebsiella spp. , respectively, in county hospitals. All of the three rates were lower than that in the teaching hospital and the difference was statistically significant （P〈0. 01）. However, the incidence of methicillin-resistant CNS （MRCNS） reached to 70 % （109/156） in the two classes of hospitals. Generally, the antimicrobial resistant rates in the county hospitals were lower than those in the teaching hospital, except the resistant rates of ciprofloxacin, erythromycin, clindamycin, SMZco which were similar in the two classes of hospitals. There were differences between county hospitals and the teaching hospital in the distribution of clinical isolates and prevalence of antimicrobial resistance. It was the basis of rational use of antimicrobial agents to monitor antimicrobial resistance by each hospital.

Antimicrobial Susceptibility Profiles among <i>Escherichia coli</i>Strains Isolated from Athi River Water in Machakos County, Kenya

Antimicrobial use in agriculture, livestock and human health has increased over the years leading to the increase in antimicrobial resistance that can also find its way to the aquatic environment. Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of multidrug resistant (MDR) strains to animals and humans using water. A total of 318 water samples were collected from six different sampling points along Athi River and E. coli isolates were subjected to Kirby-Bauer diffusion method for antimicrobial susceptibility testing. The total mean coliform count of the sampled sites was 2.7 × 104 (cfu/mL). E. coli isolates were most resistant to ampicillin (63.8%) and most susceptible to gentamicin (99.4%). MDR strains (resistance to ≥3 classes of antibiotics) accounted for 65.4% of all the isolates. The site recorded to have human industrial and agricultural zone activities had strains that were significantly more resistant to ampicillin, cefoxitin, amoxicillin/clavulanic acid (P ≤ 0.05) than isolates from the section of the river traversing virgin land and land with minimum human activities. This study indicates that E. coli strains isolated from Athi River were highly MDR and most resistant to some antimicrobial classes (ampicillin and cefoxitin) which constitute a potential risk to human and animal health.

Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital,Indonesia

Objective:To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit(ICU) of a tertiary care of Falmawati Hospital Jakarta Indonesia.Methods:A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods,and(heir antibiotic susceptibility testing was performed using disk diffusion method.Results:Specimens were collected from 385 patients who were given antimicrobial treatment,of which 249(64.68%) were cultured positive and 136(35.32%) were negative.The most predominant isolate was Pseudomonas aeruginosa(P.aeruginosa)(26.5%) followed by Klebsiella pneumoniae(K.pneumoniae)(15.3%) and Staphylococcus epidermidis(14.9%).P.aeruginosa isolates showed high rate of resistance to cephalexin(95.3%),cefotaxime(64.1%),and ceftriaxone(60.9%).Amikacin was the most effective(84.4%) antibiotic against P.aeruginosa followed by imipenem(81.2%),and meropenem(75.0%).K.pneumoniae showed resistance to cephalexin(86.5%),ceftriaxone(75.7%),ceftazidime(73.0%),cefpirome(73.0%) and cefotaxime(67.9%),respectively.Conclusions:Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins,and quinolone antibiotics.Regular surveillance of antibiotic susceptibility pallerns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

Six-year analysis of key monitoring for bacterial strain distribution and antibiotic sensitivity in a hospital

BACKGROUND With the widespread use of antimicrobial drugs,bacterial resistance has become a significant problem,posing a serious threat to public health.The prevalence of clinical infection strains in hospitals and their drug sensitivities are key to the appropriate use of antibiotics in clinical practice.AIM To identify prevalent bacteria and their antibiotic resistance profiles in a hospital setting,thereby guiding effective antibiotic usage by clinicians.METHODS Specimens from across the institution were collected by the microbiology laboratory.The VITEK 2 compact fully automatic analyzer was used for bacterial identification and antibiotic sensitivity testing,and the WHONET5.6 software was utilized for statistical analysis.RESULTS A total of 12062 bacterial strains of key monitoring significance were detected.Staphylococcus aureus demonstrated widespread resistance to penicillin,but none of the strains were resistant to vancomycin or linezolid.Moreover,219 strains of methicillin-resistant coagulase-negative staphylococci and 110 strains of methicillin-resistant Staphylococcus aureus were detected.Enterococcus faecalis showed moderate resistance to the third-generation quinolones ciprofloxacin and levofloxacin,but its resistance to nitrofurantoin and tetracycline was low.Enterococcus faecium displayed significantly lower resistance to third-and fourthgeneration quinolones than Enterococcus faecalis.The resistance of two key monitoring strains,Escherichia coli and Klebsiella pneumoniae,to piperacillin/tazobactam was 5%-8%.However,none of the Escherichia coli and Klebsiella pneumoniae strains were resistant to meropenem.The resistance of Acinetobacter baumannii to piperacillin/sulbactam was nearly 90%.Nonetheless,the resistance to tigecycline was low,and Pseudomonas aeruginosa demonstrated minimal resistance in the antibiotic sensitivity test,maintaining a resistance of<10%to the cephalosporin antibiotics cefotetan and cefoperazone over the last 6 years.The resistance to amikacin remained at 0.2%over the past 3 years.CONCLUSION Our hospital’s overall antibiotic resistance rate was relatively stable from 2017 to 2022.The detection rates of key monitoring strains are reported quarterly and their resistance dynamics are monitored and communicated to the entire hospital,which can guide clinical antibiotic selection.

Evidence-Based Use of Antibiotics in Veal Calves with Diarrhea

Diarrhea is the leading cause of mortality in beef and dairy calves during the first week of life and results in substantial financial loss [1]. Diarrhea is a multifactorial disease and can be infectious or non-infectious. However, in the majority of calves, infectious organisms, especially Cryptosporidium parvum, rotavirus, coronavirus, and E. coli, are the primary cause [2]. The aim of this study was to generate a decision tree, based on prevalence, diagnostic testing and treatment and to estimate associated costs or risk. For each of the four main pathogens, two principal approaches are outlined and compared. The first approach relies on a detailed diagnostic workup and allows for specific etiological treatment. The second approach relies on the trial-and-error method, which involves the use of a first-choice antibiotic, followed by a second- and third-choice antibiotic if the previous ones failed to resolve the disease. In Switzerland, the prevalence of diarrheic calves infected with E. coli is approximately 1% suggesting that the use of antimicrobials for the treatment of scouring calves, in the absence of a diagnostic workup, is not always justified. However, for all four major pathogens, the trial-and-error method affords cheaper treatment compared with treatment based on an etiological diagnosis. This creates a quandary in view of the current worldwide efforts to reduce the use of antibiotics in animal agriculture.

Antimicrobial susceptibility testing in veterinary medicine:performance,interpretation of results,best practices and pitfalls

The performance of antimicrobial susceptibility testing(AST)of bacteria and the interpretation of AST results for bacteria isolated from animals are complex tasks which must be performed using standard published methodology and overseen by experts in clinical microbiology and in consultation with clinical pharmacologists.Otherwise,AST has significant potential for errors and mistakes.In this review,we provide guidance on how to correctly perform AST of bacteria isolated from animals and interpret the AST results.Particular emphasis is placed on the various approved or published methodologies for the different bacteria as well as the application of interpretive criteria,including clinical breakpoints and epidemiological cut-off values(ECVs/ECOFFs).Application of approved interpretive criteria and definitions of susceptible,susceptible dose-dependent,nonsusceptible,intermediate,and resistant for clinical breakpoints as well as wild-type and non-wildtype for ECVs,are explained and the difficulties resulting from the lack of approved clinical breakpoints for other bacteria,indications,and animal species is discussed.The requirement of quality controls in any AST approach is also emphasized.In addition,important parameters,often used in monitoring and surveillance studies,such as MIC50,MIC90,and testing range,are explained and criteria for the classification of bacteria as multidrug-resistant,extensively drug-resistant or pandrug-resistant are provided.Common mistakes are presented and the means to avoid them are described.To provide the most accurate AST,one must strictly adhere to approved standards or validated methodologies,like those of the Clinical and Laboratory Standards Institute or other internationally accepted AST documents and the detailed information provided therein.

2015—2021年CHINET临床分离葡萄球菌属细菌耐药性变迁

目的了解2015-2021年中国不同地区临床分离葡萄球菌属细菌的分布及耐药变迁。方法按CHINET中国细菌耐药监测网统一的技术方案对临床分离的葡萄球菌采用纸片法和商品化药敏试验测试仪(机器法)进行药物敏感性试验;收集2015-2021年CHINET的葡萄球菌耐药监测数据,使用WHONET 5.6软件统计并按2021年CLSI折点标准判读结果。结果2015-2021年共分离非重复葡萄球菌属细菌204771株,其中金黄色葡萄球菌136731株(66.8%),凝固酶阴性葡萄球菌68040株(33.2%),7年间两者检出率均无明显变化。金黄色葡萄球菌主要分离自呼吸道标本(38.9±5.1)%、伤口脓液分泌物(33.6±4.2)%、血液(11.9±1.5)%;凝固酶阴性葡萄球菌主要分离自血液(73.6±4.2)%、脑脊液(12.1±2.5)%、胸腹水(8.4±2.1)%。金黄色葡萄球菌的科室来源主要为ICU(17.0±7.3)%、门急诊(11.6±1.7)%、外科(11.2±0.9)%;凝固酶阴性葡萄球菌的科室来源主要为ICU(32.2±9.7)%、门急诊(12.8±4.7)%、内科(11.2±1.9)%。金黄色葡萄球菌、凝固酶阴性葡萄球菌中甲氧西林耐药株的总体检出率分别为32.9%、74.1%,7年间MRSA检出率从42.1%下降至29.2%,MRCNS检出率从82.1%下降至68.2%。除甲氧苄啶-磺胺甲噁唑外,MRSA对各类抗菌药物的耐药率均高于MSSA。MRSA对庆大霉素、利福平、左氧氟沙星耐药率有所下降;MRCNS对庆大霉素、红霉素、利福平、甲氧苄啶-磺胺甲噁唑的耐药率有所下降,对左氧氟沙星的耐药率有所上升。未发现对万古霉素耐药的葡萄球菌菌株。对利奈唑胺耐药的MRCNS有所增多,7年间耐药率从0.2%上升至2.3%。结论葡萄球菌属细菌仍是革兰阳性菌中最主要的细菌。MRSA和MRCNS亦仍然是革兰阳性菌中最主要的耐药细菌。至今未发现对万古霉素和利奈唑胺耐药的金黄色葡萄球菌,但已有利奈唑胺耐药的MRCNS菌株检出,应加强监测和关注。

2015-2021年CHINET尿液分离菌分布和耐药性变迁

目的了解2015-2021年CHINET细菌耐药监测网中尿液分离菌的分布和耐药性。方法收集CHINET细菌耐药监测网51家医疗机构2015-2021年所有尿液标本临床分离菌的耐药监测数据资料,采用WHONET 5.6软件进行统计分析。结果2012-2021年尿液标本共分离细菌261893株,其中革兰阳性菌62219株,占23.8%,革兰阴性菌199674株占76.2%。常见的分离菌依次为大肠埃希菌(46.7%)、屎肠球菌(10.4%)、肺炎克雷伯菌(9.8%)、粪肠球菌(8.7%)、奇异变形杆菌(3.5%)、铜绿假单胞菌(3.4%)、无乳链球菌(2.6%)和阴沟肠杆菌(2.1%)。上述细菌主要分离自住院患者,女性多见于男性,成人多见于儿童。大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌中产超广谱β内酰胺酶(ESBL)菌株分别占53.2%、52.8%和37.0%。耐碳青霉烯类的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌中检出率分别为1.7%、18.5%、16.4%和40.3%。粪肠球菌对氨苄西林、呋喃妥因、利奈唑胺、万古霉素、替考拉宁和磷霉素的耐药率<10%,屎肠球菌对氨苄西林、左氧氟沙星、红霉素的耐药率>90%,对万古霉素、利奈唑胺和替考拉宁的耐药率<2%。ICU住院患者分离的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌对大部分抗菌药物的耐药率明显高于门诊患者和非ICU住院患者。结论尿液标本临床分离菌主要以大肠埃希菌、肠球菌和肺炎克雷伯菌为主,不同人群尿液标本中分离的细菌种类和耐药性不尽相同,应重视细菌耐药监测,减少抗菌药物的不合理使用。

一株鲫鱼致病性普通变形杆菌的鉴定及生物学特性研究

本研究对患病鲫鱼进行发病原因探究,致病菌特性分析,从而为鲫鱼病害的防控提供理论基础。通过从患病鲫鱼肝脏和肠道中分离纯化细菌,对分离菌进行16S rRNA序列分析、人工感染试验、生理生化鉴定、系统发育树构建,并通过纸片扩散法进行药敏试验,筛选敏感药物。从病鱼肝脏和肠道中均分离出菌株A,16S rRNA序列分析和理化特性均与普通变形杆菌Proteus vulgaris基本一致,人工感染试验证实菌株A为致病菌,LD50为9.77×10^(6)CFU/尾。菌株A对头孢唑啉、头孢拉定、氟苯尼考、卡那霉素、阿奇霉素及庆大霉素等6种抗生素高度敏感,对阿莫西林、红霉素、新霉素、克林霉素及多西环素等5种抗生素耐药。本次试验结果表明菌株A为普通变形杆菌,是此次鲫鱼病害的主要元凶,临床治疗可以根据药敏试验选用高度敏感抗生素进行治疗。

临床感染标本厌氧菌质谱鉴定及临床特征

目的探讨我院厌氧菌感染的种属分布、耐药性和临床特征,为临床治疗提供参考。方法收集2020年1月至2023年6月从临床感染标本中分离的非重复感染部位、非重复株厌氧菌菌株248株。采用MALDI-TOF MS技术鉴定厌氧菌种属,采用天地人微生物检测系统进行药敏试验和β-内酰胺酶实验,并进行临床分析。结果共分离248株厌氧菌,分属13个属,以拟杆菌属(44.4%)、普雷沃菌属(16.1%)和消化链球菌属(15.3%)为主。拟杆菌属中脆弱拟杆菌(74.5%)最多,主要来自分泌物、脓液和静脉血。脆弱拟杆菌对甲硝唑、氯霉素、头孢西丁、头孢三代药物、碳青霉烯类药物和β-内酰胺类复合药药物的敏感率均>85%。青霉素、氨苄西林耐药率为100%。对四环素和克林霉素耐药率>50%。β-内酰胺酶阳性率100%。结论厌氧菌是重要的感染病原体,其耐药性明显增加。实验室应加强对厌氧菌的鉴定和药敏试验指导临床合理用药,提高治疗效果。

11种抗菌药物体外联合对耐碳青霉烯类肠杆菌药物敏感性分析

目的观察两药联合对耐碳青霉烯类肠杆菌(CRE)的体外联合药物敏感性,筛选出有效的抗感染治疗方案。方法收集2023年1月至12月青岛市第八人民医院临床标本中分离的非重复CRE60株,胶体金免疫层析法检测碳青霉烯酶型,微量肉汤稀释法测定菌株的最低抑菌浓度(MIC),棋盘法对头孢他啶/阿维巴坦(CZA)联合氨曲南(ATM),黏菌素(COL)分别联合替加环素(TGC)、美罗培南(MEM)、头孢哌酮/舒巴坦(SCF)、阿米卡星(AK)、左氧氟沙星(LEV),TGC分别联合MEM、SCF和AK,MEM分别联合SCF、厄他培南(ETP)进行联合药敏试验,部分抑菌浓度指数(FIC)判定联合效果。结果60株CRE均检出碳青霉烯酶,其中肺炎克雷伯菌碳青霉烯酶(KPC)49株、新德里金属β-内酰胺酶(NDM)10株,亚胺培南酶(IMP)1株。CZA对49株产KPC菌株的MIC均≤8mg/L,全敏感;对11株产NDM、IMP酶菌株的MIC均>128mg/L,全耐药;联合ATM后协同率为100%。MEM+SCF的协同率最高,为63.4%,协同率与相加率之和为96.7%。TGC+AK的协同率与相加率最低,为31.7%。KPC酶型和NDM酶型菌株中,MEM+SCF的协同率与相加率之和最高,分别为100.0%和80.0%,COL+LEV的协同率与相加率之和最低,分别为32.6%和30.0%。11种联合方案均无拮抗作用,对CRE菌株的MIC_(范围)、MIC_(50)和MIC_(90)值与各个单药相比均有不同程度的减低。结论CZA单独或联合ATM对CRE菌株有效。MEM+SCF的协同率与相加率之和最高,可作为临床经验用药参考。

2022年CHINET三级医院细菌耐药监测

目的监测2022年CHINET三级医院临床分离菌对抗菌药物的敏感性。方法国内58所三级医院临床分离菌采用纸片扩散法或商品化药敏试验自动测试仪按CHINET统一监测技术方案进行抗菌药物敏感性试验。结果按CLSI M1002022年版折点标准判断。结果收集2022年1月1日-12月31日上述医院临床分离菌共318013株,其中革兰阳性菌占29.5%,革兰阴性菌占70.5%。金黄色葡萄球菌、表皮葡萄球菌和其他凝固酶阴性葡萄球菌(除假中间葡萄球菌和施氏葡萄球菌外)中甲氧西林耐药株的检出率分别为28.3%、76.7%和77.9%。MRSA中有94.0%的菌株对甲氧苄啶-磺胺甲噁唑敏感;MRSE中有90.8%的菌株对利福平敏感,未发现万古霉素耐药株。肠球菌属中粪肠球菌对多数测试抗菌药物的耐药率均显著低于屎肠球菌,两者中均有少数万古霉素耐药株。2022年儿童和成人中分离的非脑膜炎肺炎链球菌中PSSP的检出率分别为94.2%和95.7%。除克雷伯菌属细菌对碳青霉烯类的耐药率范围为21.7%~23.1%外,其他细菌的耐药率多在13.1%以下。除天然耐药菌株外,其他肠杆菌目细菌对替加环素、黏菌素和多黏菌素B高度敏感,耐药率范围为0.1%~13.3%。铜绿假单胞菌对美罗培南的耐药率从2019年的23.5%下降至2022年的18.0%;鲍曼不动杆菌对美罗培南的耐药率亦从2019年的79.0%下降至2022年的72.5%。结论三级医院临床分离菌对常见抗菌药物的耐药率仍呈增长趋势,但碳青霉烯类耐药肺炎克雷伯菌、铜绿假单胞菌、鲍曼不动杆菌等多种重要耐药细菌的检出率近年来呈现连续下降趋势,提示加强细菌耐药监测,开展多学科联动的方式对控制耐药细菌的流行播散是行之有效的。

一株猪源化脓隐秘杆菌的分离鉴定及其耐药性分析

为确定黑龙江省某养殖场因呼吸道症状急性死亡病猪的致病菌,并探究其主要生物学特性,本研究采集病死猪内脏组织,通过细菌分离、革兰氏染色、生化鉴定、16S r RNA基因的PCR扩增、测序、系统进化树的构建对分离菌进行种属鉴定;通过微量肉汤稀释法分析该菌对8类10种抗生素的敏感性;通过Illumina PE150对细菌全基因组测序,采用ResFinder软件分析分离菌的耐药基因,并分析耐药基因与耐药表型的相关性。利用VFanalyzer软件、BLASTN比对分离菌的毒力基因。结果显示,该菌株在10%脱纤维羊血平板培养基上培养24 h后形成表面光滑具有β-溶血环的单菌落;革兰氏染色结果显示呈蓝紫色短棒状杆菌;生化鉴定结果显示该分离菌的生化特性与化脓隐秘杆菌符合。16S r RNA基因的PCR结果显示,扩增到1397 bp的目的基因序列,与GenBank中序列比对结果显示该菌株与已报道的化脓隐秘杆菌同源性高达99%。16S r RNA基因系统进化树分析结果显示分离菌与辽宁沈阳的牛源化脓隐秘杆株TZQ 01株处于同一分支,与日本的猪源分离株NIAH13531处于较近分支,以上结果可确定该分离菌为化脓隐秘杆菌,并将其命名为FY-4-Z-1。药敏试验结果显示,该菌株对头孢菌素类的头孢噻呋,青霉素类的青霉素、阿莫西林,大环内酯类的红霉素,截短侧耳素类的泰妙菌素等抗生素敏感,对四环素类的四环素,氨基糖苷类的链霉素耐药。利用组装软件SPAdes对获得的全基因组测序数据组装后获得了分离菌全基因组草图,结果显示分离菌基因组大小为2399.961 kb;耐药基因分析结果显示,该菌株基因组包含3种耐药基因,分别是氨基糖苷类的ant(6)-la、大环内脂类的erm(X)、四环素类的tet(W)耐药基因,其中在化脓隐秘杆菌中首次检测到ant(6)-la基因。该菌株对四环素和链霉素的药敏试验结果与其耐药基因检测结果相符,而红霉素敏感表型可能与其耐药基因erm(X)的移码突变有关。利用BLASTN和VFanalyzer软件进行毒力基因检测,结果显示共检测到8个已知毒力基因和24个候选毒力相关基因。本实验进一步丰富了猪源化脓隐秘杆菌的相关研究,为规模化猪场化脓隐秘杆菌病的防治提供了重要的参考依据和用药指导。

西安某医院重症监护室常见细菌的分布特征及耐药性分析

目的 了解西安交通大学第二附属医院重症监护室(ICU)常见临床分离菌的分布特点及其耐药性。方法 回顾性分析该院 ICU 2020年1月1日-2022年12月31日临床分离菌的抗菌药物敏感性试验结果。结果 2020-2022年ICU临床分离菌3 649株,其中革兰阳性菌1 344株(36.8%)、革兰阴性菌2 305株(63.2%)。其中克雷伯菌属540株(14.8%)、肠球菌属522株(14.3%)、凝固酶阴性葡萄球菌448株(12.3%)、不动杆菌属438株(12.0%)、大肠埃希菌424株(11.6%)。甲氧西林耐药金黄色葡萄球菌(MRSA)、甲氧西林耐药表皮葡萄球菌(MRSE)和甲氧西林耐药凝固酶阴性葡萄球菌(MRCNS)的检出率分别为76.1%、82.4%和69.9%。除甲氧苄啶-磺胺甲噁唑外,MRSA、MRSE和MRCNS的耐药率均明显高于MSSA、MSSE和MSCNS。未检出葡萄球菌属对万古霉素、利奈唑胺耐药菌株。肠球菌属中屎肠球菌的耐药率高于粪肠球菌。未发现对万古霉素耐药的肠球菌属;发现2株对利奈唑胺耐药的粪肠球菌。肺炎克雷伯菌对亚胺培南和美罗培南的耐药率最高,分别为38.4%和40.2%。大肠埃希菌对亚胺培南和美罗培南的耐药率均<2.0%,而阴沟肠杆菌对该两药的耐药率>10.0%。铜绿假单胞菌对亚胺培南和美罗培南的耐药率分别为27.1%和19.6%;但鲍曼不动杆菌对该两药的耐药率高,分别为86.0%和86.7%。结论 该院ICU肺炎克雷伯菌和鲍曼不动杆菌对碳青霉烯类耐药率较高,但肠杆菌目中其他细菌对碳青霉烯类仍较敏感,细菌耐药率低。肠球菌属中已发现有对利奈唑胺的耐药菌株,未发现与万古霉素交叉耐药。因此,加强病原菌耐药性监测,合理使用抗菌药物,可以有效控制医院感染。

2018年~2021年河北省部分地区鸡源沙门菌的生物学特性及致病性研究

为调查河北地区鸡源沙门菌及其血清型的流行及分布情况,并分析其的致病性,本研究于2018年~2021年在河北省7个地区34个养鸡场共收集631份发病鸡肛拭子和62份病料样品共计693份,分别接种普通琼脂培养基分离细菌并纯化后经革兰氏染色镜检;将分离菌分别接种不同的培养基培养,并对分离菌经生化及16S r RNA基因的PCR及测序鉴定,随机选择32条测序序列经NCBI的BLAST比对,并采用DNAStar软件分析该基因的同源性。采用玻片凝集法鉴定分离菌的血清群及血清型并统计各血清群与血清型在河北不同地区的分布。结果显示,从693份病料样品中共分离到238株沙门菌,除3株未定群外,其余分离菌分属于A、B、C、D、E、F 6个血清群,其中D群最多达69.7%(166/238);238株沙门菌分属于7个不同的血清型和未定型,依次为鸡白痢沙门菌(91/38.2%)、甲型副伤寒沙门菌(43/18.0%)、鸡伤寒沙门菌(40/16.8%)、肠炎沙门菌(39/16.4%)等。血清群与血清型分布的统计结果显示,除张家口地区流行A群血清群外,其余地区流行的血清群均为D群;张家口地区流行鸡白痢沙门菌;秦皇岛地区有14种血清型,其中甲型副伤寒沙门菌为其流行血清型;石家庄、承德、唐山流行的均为鸡白痢沙门菌,邢台及保定地区分别流行肠炎沙门菌与鸡伤寒沙门菌。通过K-B药敏纸片法检测238株分离菌对7类共22种药物的敏感性;采用PCR检测分离菌的相关耐药基因并采用SPSS26.0软件中的Fisher确切概率法分析分离菌耐药表型与耐药基因之间的相关性。选取12株不同血清型的分离菌以0.2 m L/只(3×108cfu/mL)感染雏鸡,分析各分离菌对雏鸡的致病性。药敏试验结果显示,对苯唑西林、红霉素、青霉素、甲氧苄啶、氨苄西林、四环素耐药的菌株分别占97.5(232/238)、89.1%(212/238)、78.6%(187/238)、74.8%(178/238)、74.4%(177/238)、64.3%(153/238),对其它药物耐药的菌株均在32%以下,但均对头孢类药物敏感;且分离菌多呈多重耐药性(58.4%,139/238),耐6重药物的菌株(32.8%,78/238)与耐5重药物的菌株(11.8%,28/238)最多。耐药基因检测结果显示,对β-内酰胺类、磺胺类、大环内酯类、四环素类、氨基糖苷类药物的耐药基因tem、erm(B)a、tetA、strA-B的检出率分别为100%(238/238)、75.2%(178/238)、71%(169/238)、65.6%(156/238)及31.9%(76/238)。未检测到喹诺酮类和醛胺醇类耐药基因。经分析,氨基糖苷类、四环素类、磺胺类、β-内酰胺类、大环内酯类药物的耐药表型与其耐药基因的符合率分别为94.7%、98.1%、99.4%、97.5%、79.9%,相关性均较强。致病性试验结果显示,12株分离菌均能致感染鸡出现不同的临床症状及肝脏和肠道的剖检病变,且能对鸡造成不同程度的死亡,其中以致鸡死亡10只(100%)、7只(87%)为主,并从死亡鸡的肝脏再次分离到相应细菌。上述结果表明,本研究从河北不同地区分离的238株沙门菌血清群与血清型众多,大多数沙门菌的耐药性较强且多呈多重耐药性,其携带的5类药物的耐药基因与其相对应的耐药表型均呈较强的相关性,且分离菌对雏鸡呈不同的致病性。本研究为河北地区鸡源沙门菌的流行病学调查及其感染的防治提供参考依据。

皮氏罗尔斯顿菌感染患者42例临床特征及菌株药物敏感性

目的研究临床分离获得的皮氏罗尔斯顿菌感染患者的临床特征及菌株药敏试验结果,为临床合理使用抗菌药物提供依据。方法回顾性分析2014年1月—2023年12月于天津市第一中心医院就诊的皮氏罗尔斯顿菌感染住院患者,分析皮氏罗尔斯顿菌的临床特征及药敏试验数据。结果10年内共分离出罗尔斯顿菌属80株,其中非重复皮氏罗尔斯顿菌42株(52.5%)。42株皮氏罗尔斯顿菌中,64.3%分离自男性患者;分离自痰、导管、血、咽拭子、引流液标本的菌株分别占38.1%、28.6%、19.0%、4.8%、2.4%;临床来源科室分布以重症监护科病房(ICU)占比最高(52.4%);感染患者例数随年份先升后降,之后呈小幅波动,各科室感染患者例数随年份变化差异不具有统计学意义(P>0.05)。皮氏罗尔斯顿菌对多西环素、左氧氟沙星、环丙沙星、米诺环素等药物具有较高的敏感率,敏感率为78.3%~90.9%;而对复方磺胺甲口恶唑、头孢唑林则完全(100%)耐药,对氨曲南、黏菌素、头孢替坦、妥布霉素、阿米卡星、头孢他啶、庆大霉素同样具有较高的耐药率(80.0%~97.4%)。对21种抗菌药物在不同年份间的耐药率变化比较,差异均无统计学意义(均P>0.05)。结论皮氏罗尔斯顿菌主要来自ICU,感染人群以成年男性居多,从痰和导管标本中分离出的菌株最多;菌株呈现多重耐药,应注意对常用抗菌药物的耐药率变迁,加强细菌耐药动态监控,指导临床合理选择抗菌药物,实施早期有效治疗以改善患者预后。