The effect of carbapenem resistance in Klebsiellae on infection outcomes in animals and birds

It is often said that the emergence of antimicrobial drug resistance(AMR)in pathogens is the major cause of mortality.In the present study,clinical microbiology data on infections caused by Klebsiella pneumoniae strains and their antimicrobial drug resistance specifically to carbapenems retrieved from Clinical Epidemiology database of the Institute were analysed to determine the impact of carbapenem resistance in Klebsiellae isolated from the clinical samples of veterinary cases and outcome of the infection because in a few recent reports it is claimed that the presence of carbapenem-resistant Klebsiellae is associated with higher mortality in humans due to Klebsiella infections.The retrospective analysis of Klebsiella infections in animals and birds revealed that 21.8%of K.pneumoniae causing pneumonic or septicemic infections were carbapenem-resistant but the carbapenem resistance was not associated with increased numbers of deaths or recovery.It may be probably due to the fact that carbapenem drugs were not used for the treatment of infected animals and carbapenem resistance may not be associated with the lethality potential of Klebsiellae.

Klebsiella pneumoniae infections after liver transplantation:Drug resistance and distribution of pathogens,risk factors,and influence on outcomes

BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneumoniae infections(KPIs)in the bloodstream are common in LT recipients.We hypothesized that KPIs and carbapenemresistant Klebsiella pneumoniae(CRKP)infections may affect the outcomes of LT recipients.AIM To assess KPI incidence,timing,distribution,drug resistance,and risk factors following LT and its association with outcomes.METHODS This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University,a tertiary hospital,from January 2015 to January 2023.We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.RESULTS KPI incidence was 7.9%(n=32),with lung/thoracic cavity the most frequent site of infection;the median time from LT to KPI onset was 7.5 d.Of 44 Klebsiella pneumoniae isolates,43(97.7%)and 34(77.3%)were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline,respectively;>70%were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin.Female sex[odds ratio(OR)=2.827,95%confidence interval(CI):1.256-6.364;P=0.012],pre-LT diabetes(OR=2.794,95%CI:1.070-7.294;P=0.036),day 1 post-LT alanine aminotransferase(ALT)levels≥1500 U/L(OR=3.645,95%CI:1.671-7.950;P=0.001),and post-LT urethral catheter duration over 4 d(OR=2.266,95%CI:1.016-5.054;P=0.046)were risk factors for KPI.CRKP infections,but not KPIs,were risk factors for 6-month all-cause mortality post-LT.CONCLUSION KPIs occur frequently and rapidly after LT.Risk factors include female sex,pre-LT diabetes,increased post-LT ALT levels,and urethral catheter duration.CRKP infections,and not KPIs,affect mortality.

Occurrence of K1 and K2 serotypes and genotypic characteristics of extended spectrumβ-lactamases-producing Klebsiella pneumoniae isolated from selected hospitals in Malaysia

Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.

Klebsiella aerogenes的胞外聚合物产量优化及其对碳酸钙晶型的调控作用

通过响应面法确定产气克雷伯氏杆菌(Klebsiella aerogenes)产胞外聚合物(EPS)的最优培养条件,并开展EPS质量浓度对Klebsiella aerogenes诱导形成碳酸钙晶型影响的试验研究。研究结果表明,相较于pH和接种量,培养时间和温度对菌株EPS产量的影响更为显著,EPS最优培养条件如下:培养时间为4.64 d、培养温度为28.35℃、接种量为2.97%、pH=7.69,在此条件下,EPS的产量可达210.24 mg/L;当添加的EPS质量浓度从0 g/L增加到1.0 g/L时,方解石的质量分数从27.1%提高至98.3%,球霰石的质量分数从72.9%下降至1.7%,表明EPS能有效促进方解石的形成并抑制球霰石的形成;EPS中带负电荷的官能团可以吸附溶液中Ca~(2+),使得溶液中Ca~(2+)浓度减小、过饱和度降低从而促进方解石型碳酸钙晶体的生成。可以通过EPS来调控Klebsiella aerogenes诱导形成方解石和球霰石的质量分数,强化碳酸钙晶体向热力学稳定的方解石型碳酸钙转化,这为提高微生物诱导碳酸钙沉淀形成的固化体的力学强度提供了新的思路。

一株大口黑鲈源ST-873型肺炎克雷伯菌(Klebsiella pneumoniae)的分离鉴定及生物学特性研究

从患腹水病大口黑鲈(Micropterus salmoides)的头肾、脾脏、肝脏组织中分离到一株优势菌,生长出圆形、边缘整齐的灰白色黏液状菌落;染色镜检可见短粗、卵圆形、有荚膜的革兰氏阴性杆菌。结合形态、生理生化特征、16S rRNA基因序列分析鉴定为肺炎克雷伯菌(Klebsiella pneumoniae),MLST分析进一步确定其为ST-873型,与ST-65型聚为一支;该菌株携带aere、alls、wca和ybt四种毒力基因,具有溶血活性;人工感染大口黑鲈,发现患病鱼呈现腹水等与自然发病类似的症状,且病鱼内脏的分离菌株与攻毒菌株相同;经统计,其LD50为3.4×10^(7) CFU/mL,具有中等生物被膜形成能力。耐药性分析结果显示,该菌株携带bla-shv、sul2、aadA和tetB四种耐药基因,对β-内酰胺类、氨基糖苷类、喹诺酮类、黏菌素类药物敏感,对四环素类、磺胺类、林可酰胺类、利福霉素类耐药;中药三七、款冬花对分离菌株有明显抑制作用。研究探明了大口黑鲈腹水病的主要病原,可为鱼源肺炎克雷伯菌的诊断和防治提供科学依据和数据参考。

Colonization by Klebsiella variicola FH-1 stimulates soybean growth and alleviates the stress of Sclerotinia sclerotiorum

Sclerotinia stem rot,caused by Sclerotinia sclerotiorum,is a destructive soil-borne disease leading to huge yield loss.We previously reported that Klebsiella variicola FH-1 could degrade atrazine herbicides,and the vegetative growth of atrazine-sensitive crops(i.e.,soybean)was significantly increased in the FH-1-treated soil.Interestingly,we found that FH-1 could promote soybean growth and induce resistance to S.sclerotiorum.In our study,strain FH-1 could grow in a nitrogen-free environment,dissolve inorganic phosphorus and potassium,and produce indoleacetic acid and a siderophore.The results of pot experiments showed that K.variicola FH-1 promoted soybean plant development,substantially improving plant height,fresh weight,and root length,and induced resistance against S.sclerotiorum infection in soybean leaves.The area under the disease progression curve(AUDPC)for treatment with strain FH-1 was significantly lower than the control and was reduced by up to 42.2%within 48 h(P<0.001).Moreover,strain FH-1 rcovered the activities of catalase,superoxide dismutase,peroxidase,phenylalanine ammonia lyase,and polyphenol oxidase,which are involved in plant protection,and reduced malondialdehyde accumulation in the leaves.The mechanism of induction of resistance appeared to be primarily resulted from the enhancement of transcript levels of PR10,PR12,AOS,CHS,and PDF1.2 genes.The colonization of FH-1 on soybean root,determined using CLSM and SEM,revealed that FH-1 colonized soybean root surfaces,root hairs,and exodermis to form biofilms.In summary,K.variicola FH-1 exhibited the biological control potential by inducing resistance in soybean against S.sclerotiorum infection,providing new suggestions for green prevention and control.

Atypical pompholyx presentation of secondary Staphyloccoccus and Klebsiella infections in a patient with premorbid Ebstein anomaly: A case report

Rationale: Pompholyx refers to pruritic vesicles or bullous rash that mainly distribute on the palms and lateral surfaces of the fingers. It is less common among Asians, and in a severe condition, secondary bacterial infection of pompholyx can happen and result in pain, swelling and pustules.Patient concerns: A 15-year-old girl complained of progressive wound and small bumps containing yellowish pus and crusts on her hands and feet for over 6 months and worsened in the last month before admission. She also had Ebstein anomaly.Diagnosis: Atypical pompholyx with secondary Staphylococcus and Klebsiella infections. Interventions: Wound care with wet dressing and applying moisturizer on crusts, application of antibiotics for Gram positive and negative bacteria and giving nutritional support with reckoning of proper calories. Outcomes: Skin lesions were completely healed and the patient was discharged after 10 days of hospitalization.Lessons: Atypical manifestation of pompholyx makes it hard to diagnose. The diagnosis can be confirmed with meticulous historytaking and physical examination. Wound caring and controlling of the infection should be done to earn an optimal outcome.

Newly Detected Transmission of bla_(KPC-2) by Outer Membrane Vesicles in Klebsiella Pneumoniae

Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins and other factors involved in various biological processes,includingβ-lactamase and antibiotic-resistance genes.This study aimed to reveal the transmission mechanism of OMV-mediated drug resistance of Klebsiella(K.)pneumoniae.Methods We selected CR-KP producing K.pneumoniae carbapenemase-2(KPC-2)to study whether they can transfer resistance genes through OMVs.The OMVs of CR-KP were obtained by ultracentrifugation,and incubated with carbapenem-sensitive K.pneumoniae for 4 h.Finally,the carbapenem-sensitive K.pneumoniae was tested for the presence of bla_(KPC-2)resistance gene and its sensitivity to carbapenem antibiotics.Results The existence of OMVs was observed by the electron microscopy.The extracted OMVs had bla_(KPC-2)resistance gene.After incubation with OMVs,bla_(KPC-2)resistance gene was detected in sensitive K.pneumoniae,and it became resistant to imipenem and meropenem.Conclusion This study demonstrated that OMVs isolated from KPC-2-producing CR-KP could deliver bla_(KPC-2)to sensitive K.pneumoniae,allowing the bacteria to produce carbapenemase,which may provide a novel target for innovative therapies in combination with conventional antibiotics for treating carbapenem-resistant Enterobacteriaceae.

Nosocomial Klebsiella variicola Infection in Neonatal Intensive Care: A New Emerging Pathogen

Klebsiella variicola is a human pathogen that has been misidentified as K. pneumoniae. This misidentification has led to a lack of understanding of important clinical and biological aspects of this bacterial species. It is responsible for serious and potentially fatal infections, with a prevalence of multi-resistance to routine antibiotics. We present through three clinical observations, the case of three newborns having been hospitalized in the neonatal intensive care unit and whose evolution was complicated by the occurrence of a nosocomial infection in front of which a blood culture was done on blood agar, with a manual antibiogram on antibiotic disks, isolated the germ Klebsiella variicola. The management of the newborns was initially centered on non-invasive ventilation with a bi-antibiotic therapy based on carbapenem and amikacin for two newborns and switched to colymicin for the third case. Newborn follow-up was based on assessment of general condition, clinical signs of infection, as well as a biological control made of a blood count, a c-reactive protein, a complete ionogram, and a blood culture, every four days or if signs of clinical call. The evolution was favorable for two cases with good clinical and biological improvement, and complicated by death due to alveolar hemorrhage in the third case. Given the high pathogenicity of this germ, and the frequency of misidentification, it is crucial to know the clinical spectrum of Klebsiella variicola infections in neonatal intensive care units, in order to adapt the antibiotic therapy and to mitigate the fulminant evolution of this germ.

Resistance of Klebsiella to Imipenem by Production of Carbapenemase Gene blaIMP at Centre Hospitalier Universitaire Pédiatrique Charles de Gaulle, Ouagadougou, Burkina Faso

Objective: Class B carbapenemases are bacterial enzymes that catalyze the hydrolysis of β-lactam core antibiotics, except for monobactams. The objective of this study was to identify the carbapenemase gene blaIMP in the genus Klebsiella at the Charles De Gaulle Pediatric University Hospital (CHUP-CDG) of Ouagadougou, Burkina Faso. Methods: The study involved 17 bacterial strains responsible for human infection and isolated from various biological samples during the period from 2009 to 2013. The strains were tested for antimicrobial susceptibility to cefotaxime, ceftazidime and imipenem using the Mueller-Hinton agar diffusion method. The carbapenemases resistance genes were detected by conventional PCR using specific primers at the molecular biology laboratory of CERBA/LABIOGENE, Ouagadougou, Burkina Faso. Results: The antibiotic susceptibility test showed high resistance of the 17 Klebsiella isolates tested to cephalosporins. A high cefotaxime-resistance rate (82.35%) and ceftazidime-resistance rate (88.23%) was found among the strains tested against 11.76% resistance rate for imipenem. Analysis of PCR products by gel electrophoresis revealed 4 strains (23.53%) with blaIMP-type gene. Conclusion: Klebsiella is a well-known bacterium in clinical practice. The present study demonstrated the blaIMP-type gene in cephalosporin-resistant strains of Klebsiella at CHUP-CDG. More effective monitoring and treatment solutions are needed to prevent the spread of these resistant strains.

Isolation and Identification Methods for Oral Klebsiella pneumoniae Involved in Onset of Inflammatory Bowel Disease

Purpose: Recently, it was reported that Klebsiella pneumoniae is related to the onset of inflammatory bowel disease including the Crohn disease. It was frequently reported that K. pneumoniae was detected in human oral cavities. Regrettably, it currently remains unclear whether K. pneumoniae is part of the normal oral flora. The aim of this study was to establish the isolation and identification methods for K. pneumoniae from human oral cavities, and investigate its transmission pattern. Methods: A selective medium, OKPSM, for the isolation of K. pneumoniae from oral cavities was developed in this study. Also, PCR primer for the identification and detection at subspecies level of K. pneumoniae was designed. Results: OKPSM and PCR method using the primers designed in this study were useful for the isolation and identification of K. pneumoniae from human oral cavities. K. pneumoniae subsp. pneumoniae was detected at 10.0% in 30 saliva samples. On the other hand, K. pneumoniae subsp. ozaenae and K. pneumoniae subsp. rhinoscleromatis were detected from no sample. Moreover, K. pneumoniae subsp. pneumoniae isolates from same subject at 0 month and after 3 months showed same genotypes on AP-PCR using OPA-07 primer. Conclusion: These results indicated that human oral cavities were not suitable for the habitat of K. pneumoniae.

Successful treatment of invasive liver abscess syndrome caused by Klebsiella variicola with intracranial infection and septic shock:A case report

BACKGROUND Klebsiella variicola(K.variicola)is a member of the Klebsiella genus and is often misidentied as Klebsiella pneumoniae.In this report,we present a rare case of invasive liver abscess caused by K.variicola.CASE SUMMARY We report a rare case of liver abscess due to K.variicola.A 57-year-old female patient presented with back pain for a month.She developed a high-grade fever associated with chills,and went into a coma and developed shock.The clinical examinations and tests after admission confirmed a diagnosis of primary liver abscess caused by K.variicola complicated by intracranial infection and septic shock.The patient successfully recovered following early percutaneous drainage of the abscess,prompt appropriate antibiotic administration,and timely open surgical drainage.CONCLUSION This is a case of successful treatment of invasive liver abscess syndrome caused by K.variicola,which has rarely been reported.The findings of this report point to the need for further study of this disease.

Prevalence and Associated Risk Factors of Uropathogenic Klebsiella Species in Port Harcourt

Background: Urinary tract infection (UTI) is a severe public health issue that affects a wide range of people around the world with Klebsiella pneumoniae accounting for up to 25% of all urinary tract infections. The higher rate of UTI associated with uropathogenic Klebsiella species has been associated with the emergence of hypervirulent and antibiotic-resistant strains facilitated by the misuse and overuse of antibiotics as well as other sociodemographic and behavioural practices of susceptible individuals. This study was aimed at investigating the prevalence and associated risk factors of uropathogenic Klebsiella species in Port Harcourt, Nigeria. Methodology: The study employed a descriptive cross-sectional study design comprising 300 subjects clinically suspected of having urinary tract infections attending the Rivers State University Medical Centre and the Rivers State University Teaching Hospital between March to August 2022. A standard urine culture procedure was used to ascertain significant bacteriuria after which Klebsiella colonies were isolated and identified using standard bacteriological techniques. The data generated from this study was represented as frequency and percentages, and inferential statistics were carried out using Chi-square with the aid of GraphPad Prism Software Version 9. Statistical significance was defined as a p-value of less than 0.05 at a 95% confidence interval. Result: The prevalence of uropathogenic Klebsiella sp. was 16%, with sex, pregnancy status, and religion of the individuals substantially linked (p p Klebsiella species. Conclusion: This study reports a relatively high prevalence of uropathogenic Klebsiella species at 16%, with the sex and pregnancy status of the subjects being significantly associated (p Klebsiella species in the current study. Health promotion and awareness efforts should be prioritised to inform susceptible demographics about their risks for urinary tract infections associated with uropathogenic Klebsiella species via targeted educational campaigns, collaboration with healthcare providers, use of social media and online platforms, workplace wellness programs, and community outreach programs amongst others. Antimicrobial susceptibility testing before prescriptions and treatment should be emphasized and upheld in all clinical settings.

大豆根际溶无机磷细菌Klebsiella sp.wj6的分离鉴定与溶磷特性分析

[目的]为了明确黑土种植的大豆根际溶磷菌的种类及不同溶磷菌溶无机磷的特性,并有效利用溶磷菌,增加黑土的可持续利用能力。[方法]以NBRIP为分离培养基从大豆根际土壤中分离到1株溶磷菌(命名为wj6),采用Vitek 2自动分析系统和16S rDNA方法对其进行鉴定;以NBRIP分离培养基为基础,利用L25(53)正交设计试验,从碳源、氮源及pH值3个方面对菌株wj6溶磷培养基进行优化;利用优化后的NBRIP培养基测定wj6溶解Ca3(PO4)2、FePO4和AlPO4的特点以及溶磷过程中磷酸酶活性和葡萄糖脱氢酶活性。[结果]经Vitek 2自动分析系统和16S rDNA方法鉴定菌株wj6为Klebsiella sp.。菌株wj6以葡萄糖和蛋白胨为碳源和氮源,pH值为8时溶磷量最高;对Ca3(PO4)2、FePO4、AlPO4均有较强的溶解能力,最高溶磷量分别为409.28、60.59和32.90μg·m L-1。菌株wj6在溶解FePO4和AlPO4时受环境pH值的影响较大,当接种到pH值为8的溶磷培养基中,能溶解FePO4和AlPO4,而在培养基原液(pH3)中不具有溶磷能力;以Ca3(PO4)2为唯一磷源,在溶磷过程中酸性磷酸酶、碱性磷酸酶和葡萄糖脱氢酶活性先增加后减小,36 h内葡萄糖脱氢酶活性较大,与其他时间内酶活差异显著。[结论]从大豆根际分离到的溶磷菌Klebsiella sp.wj6在不同难溶性磷酸盐中溶磷能力差异较大,且溶磷受环境pH值的影响。磷酸酶和葡萄糖脱氢酶在溶磷过程中起重要作用。

Klebsiella pneumoniae合成1,3-丙二醇过程中的生长与催化耦联

This paper focuses on the research of the bioconversion of 1,3-propanediol by Klebsiella pneumoniae. The linear correlation of cell growth and 1,3-propanediol synthesis was found. An equation of the relationship between cell growth and biocatalysis was given.With the analysis of metabolism, it was discovered that the cell regulated the NADH production by cell growth in order to supply enough reductive equivalent for enzyme catalysis. A conclusion was drawn that the cell growth was coupled with the reactivation of a key-enzyme which catalyzes 1,3-propanediol production in Klebsiella pneumoniae.

甲酸脱氢酶在Klebsiella pneumoniae中的表达和功能分析

在甘油厌氧发酵生产1,3-丙二醇的过程中,需要消耗还原当量NADH,NADH的有效供给决定了1,3-丙二醇的产量和得率。采用PCR方法从Candidaboidinii基因组中克隆编码甲酸脱氢酶基因fdh,将fdh基因片段插入载体pMALTM-p2X中,构建表达载体pMALTM-p2X-fdh,并转入1,3-丙二醇生产菌Klebsiella pneumoniae YMU2,获得重组菌Klebsiella pneumoniae F-1。研究了重组质粒的稳定性和IPTG诱导fdh基因过量表达的条件。结果表明,重组质粒具有良好的稳定性;fdh基因表达的蛋白分子量为40.2kDa;IPTG诱导表达研究表明,在IPTG浓度为0.5mmol/L时,诱导4h后甲酸脱氢酶表达明显;发酵过程中甲酸脱氢酶比酶活达到5.47U/mg;与出发菌株K.pneumoniae YMU2相比,重组菌F-1合成1,3-丙二醇的浓度提高了12.5%。

源于克雷伯氏菌Klebsiella sp. AC-11的3株噬菌体的生物学特性

从国家海洋局第三海洋研究所海水养殖池中分离得到一株细菌AC-11,16SrDNA序列分析表明其与肺炎克雷伯氏菌肺炎亚种(Klebsiella pneumoniaesub sp. pneumoniae)具有最高的序列同源性达99.78%。以此菌株为宿主菌,于2008年11月采用双层平板法分离得到3株裂解性噬菌体KP1,KP2和KP3,其中KP2分离自同一海水养殖池,另外2株则来源于厦门筼筜湖海水样品。分别对宿主菌及噬菌体进行了电镜形态观察,并对噬菌体进行了BglⅡ和EcoRⅤ两种酶的限制性酶切分析,发现它们均属于长尾噬菌体科(Siphoviridae),但具有不同的酶切图谱;同时测定了3株噬菌体的最佳感染复数、一步生长曲线及对温度、pH、紫外线、乙醚和氯仿等理化因素的敏感性等生理特性。实验结果表明3株噬菌体具有不同的生物学特性,为不同株型。本研究丰富了对噬菌体多样性的认识,并为进一步应用噬菌体诊断和治疗潜在的由肺炎克雷伯氏菌引发的疾病及细菌分型等研究提供了理论基础。

维生素C和E对Klebsiella pneumoniae合成1,3-丙二醇的调控

通过外源添加还原剂的方式调控细胞内NADH/NAD再生系统的状态,研究了40～150 mg/LVC及20～100mg/LVE对Klebsiella penumoniae合成1,3-丙二醇的影响,发现外源添加150 mg/L VC或30 mg/L VE均可使1,3-PD合成浓度提高20%～30%;但同时也提高了某些副产物的合成浓度,对代谢流分布的调控作用不明显;1,3-丙二醇得率稍有提高但不显著.提高1,3-pD得率宜从代谢节点(丙酮酸)通量调节方面考虑.

微波与NTG复合诱变育种Klebsiella高产异淀粉酶突变株

从原始菌克雷伯氏菌(Klebsiella)出发,经过微波与NTG复合诱变后,筛选、初筛分离得高产异淀粉酶的菌株NCP-03,酶活力由原来的28U/mL提高到210U/mL,比原始菌种产酶活力提高了近7倍。并对NCP-03发酵产酶条件进行了初步优化。

利用氧化还原电位调控基因工程菌株Klebsiella pneumoniae F-1合成1,3-丙二醇

基因工程菌株Klebsiella pneumoniae厌氧发酵过程中,氧化还原电位(ORP)是一个监控发酵过程的重要指标.考察了K.pneumoniae F-1在不同ORP(-190,-210,-240和-290mV)下菌体生长和代谢产物合成的情况.在ORP为-240mV时,1,3-丙二醇的发酵终浓度和得率分别为81.5g/L和0.423mol/mol,分别为4种ORP条件下的最高值.这说明ORP=-240mV是菌株K.pneumoniae F-1的最适ORP.此ORP既不同于野生菌株K.pneumoniae M5aL的最适ORP(-190mV),也不同于经过诱变的菌株K.pneumoniae YMU2的最适ORP(-280mV).另外,通过研究发酵体系ORP对甘油代谢流的影响,发现还原性氛围较有利于甘油向1,3-PD、乙醇、2,3-丁二醇等还原性较高的代谢物转化.首次报道了ORP调控发酵过程在基因工程改造菌株中的应用,这对于进一步研究ORP调控厌氧发酵过程具有一定的意义.