Identificación de enterobacterias productoras de carbapenemasas en el Hospital Universitario Católico de Cuenca / Identification of carbapenemase producing enterobacteriaceae at the Catholic University Hospital of Cuenca / Identificação de enterobacteriaceae produtoras de carbapenemase no Hospital Universitário Católico de Cuenca

Las enterobacterias productoras de carbapenemasas desarrollan infecciones resistentes a los medicamentos en neumonía, infección del tracto urinario e infecciones relacionadas con dispositivos. Klebsiella pneumoniae, Escherichia coli y Enterobacter cloacae son amenazas de resistencia emergentes importantes a nivel mundial, lo que representa alta mortalidad y limitadas opciones de tratamiento. Objetivo: detectar la presencia de EPC de clase A, mediante la aplicación del test fenotípico de sinergia con ácido borónico en cepas de enterobacterias aisladas de superficies inertes en el Hospital Universitario Católico de Cuenca, Ecuador. Materiales y Métodos: estudio cuali-cuantitativo de tipo experimento puro de corte transversal y alcance exploratorio - descriptivo. Las enterobacterias se identificaron mediante test bioquímicos del sistema estandarizado API 20 E. Para la detección fenotípica de carbapenamasas de clase A se utilizó el método de sinergia de discos con ácido borónico y discos imipenem, meropenem y ertapenem. Resultados: se identificaron 25 géneros de enterobacterias, el 24 % fue Pseudomonas aeruginosam, el 20 % de enterobacterias fue productoras de carpapenemasas clase Am mientras que el 32 % fue resistente para los tres carbapenémicos en estudio, el 68 % mostró sensibilidad para imipenem, el 56 % para meropenem y 44 % para ertapenem. El 48 % de enterobacterias fueron resistentes a ertapenem, el 44 % a meropenem y 32 % a imipenem. Conclusiones: Enterobacterias como P. aureginosa, E. cloacae, Cronobacter spp. y E. coli presentan mecanismos de resistencia asociados a carbapenemasas clase A tipo KPC por lo que se recomienda vigilancia continua y estrategias de manejo para abordar la resistencia a carbapenémicos en entornos hospitalarios

Carbapenemase-producing Enterobacteriaceae develop drug-resistant infections in pneumonia, urinary tract infection, and device-related infections. Klebsiella pneumoniae, Escherichia coli, and Enterobacter cloacae are important emerging resistance threats globally, representing high mortality and limited treatment options. Objective: detect the presence of class A EPC, by applying the phenotypic synergy test with boronic acid in strains of enterobacteria isolated from inert surfaces at the Catholic University Hospital of Cuenca, Ecuador. Materials and Methods: Qualitative-quantitative study of pure cross-sectional experiment type and exploratorydescriptive scope. Enterobacteriaceae were identified using biochemical tests of the standardized API 20 E system. For the phenotypic detection of class A carbapenamases, the synergy method of disks with boronic acid and imipenem, meropenem and ertapenem disks was used. Results: 25 genera of enterobacteria were identified, 24 % were Pseudomonas aeruginosam, 20 % of enterobacteria were producers of class Am carbapenemases while 32 % were resistant to the three carbapenems under study, 68 % showed sensitivity to imipenem, 56 % for meropenem and 44 % for ertapenem. 48 % of enterobacteria were resistant to ertapenem, 44 % to meropenem and 32 % to imipenem. Conclusions: Enterobacteriaceae such as P. aureginosa, E. cloacae, Cronobacter spp. and E. coli present resistance mechanisms associated with class A carbapenemases type KPC, so continuous surveillance and management strategies are recommended to address resistance to carbapenems in hospital environments

Enterobacteriaceae produtoras de carbapenemases desenvolvem infecções resistentes a medicamentos em pneumonia, infecção do trato urinário e infecções relacionadas a dispositivos. Klebsiella pneumoniae, Escherichia coli e Enterobacter cloacae são importantes ameaças emergentes de resistência em todo o mundo, representando alta mortalidade e opções de tratamento limitadas. Objetivo: detectar a presença de CPE classe A, aplicando o teste de sinergia fenotípica com ácido borônico em cepas de enterobactérias isoladas de superfícies inertes no Hospital Universitário Católico de Cuenca, Equador. Materiais e Métodos: estudo cualitativo quantitativo, do tipo experimento transversal puro e escopo exploratório-descritivo. As enterobactérias foram identificadas por meio de testes bioquímicos do sistema padronizado API 20 E. Para a detecção fenotípica das carbapenamases classe A foi utilizado o método de sinergia de discos com ácido borônico e discos de imipenem, meropenem e ertapenem. Resultados: foram identificados 25 gêneros de enterobactérias, 24 % eram Pseudomonas aeruginosam, 20 % das enterobactérias eram produtoras de carbapenemases da classe Am enquanto 32 % eram resistentes aos três carbapenêmicos em estudo, 68 % apresentaram sensibilidade ao imipenem, 56 % ao meropenem e 44. % para ertapenem. 48 % das enterobactérias eram resistentes ao ertapenem, 44 % ao meropenem e 32 % ao imipenem. Conclusões: Enterobacteriaceae como P. aureginosa, E. cloacae, Cronobacter spp. e. coli apresentam mecanismos de resistência associados às carbapenemases classe A tipo KPC, portanto estratégias contínuas de vigilância e manejo são recomendadas para abordar a resistência aos carbapenêmicos em ambientes hospitalares.

Detection of colistin susceptibility in extended spectrum ? lactamases positive Klebsiella pneumoniae and Escherichia coli clinical isolates by broth disc elution method

Background: Antibiotic resistance is one of the greatest threats in human health. Extended spectrum ? lactamases mediated resistance is prevalent worldwide, Klebsiella pneumoniae and Escherichia coli leap out as this significant ESBL producers conferring resistance to the expanded spectrum cephalosporins. Colistin is being administered as last line therapy for patients that have failed to respond to other available antibiotics that are active against Gram-negative bacteria. Methods: The present study was conducted at school of medical education Kottayam, Kerala from January 2023 to November 2023.During the period of study 150 isolates of K. pneumoniae and 136 isolates of E. coli were collected from various diagnostic microbiology laboratories in Kerala. The colistin susceptibility pattern of ESBL producing isolates was detected by broth disc elution method recommended by CLSI. Results: In this study prevalence of multi-drug resistant is 6% and 9.6% and Extensively-drug resistant is 62% and 63.9% for K. pneumoniae and E. coli respectively. ESBL production was detected as 72% in K. pneumoniae and 79% in E. coli. The colistin susceptibility pattern of ESBL producing K. pneumoniae and E. coli was detected as 76.9% and 87.9% respectively Conclusions: Our result demonstrated that the recent use of colistin as last resort treatment for extensively drug resistant gram-negative bacilli, it is essential to know the prevalence of susceptibility pattern to this antibiotic.

Evaluation of antimicrobial activity of Lactobacillus acidophilus and Lactobacillus rhamnosus against clinically isolated Klebsiella pneumoniae: an in vitro study

Background: Klebsiella pneumoniae are Gram-negative opportunistic pathogen, belonging to the family Enterobacteriaceae that can cause severe nosocomial infections particularly in immuno-compromised individuals. They exhibit co-resistance to multiple antibiotics which emphasize the need for non-antibiotic therapies. The goal of the presented study was to investigate the antimicrobial ability of probiotic Lactobacilli on clinical isolates of K. pneumoniae. Methods: In this cross-sectional study, antimicrobial activities of probiotic L. acidophilus and L. rhamnosus on K. pneumoniae were evaluated by Agar overlay interference technique. Clear zone around Lactobacilli were taken as positive inhibition. Antibiotic susceptibility profiles of K. pneumoniae were determined by Kirby-Bauer disk diffusion method, analyzed using interpretive standards of CLSI M100-S33 and categorized into MDR, XDR and Non MDR groups. Statistical analysis was done using descriptive statistics such as mean and standard error and inferential statistics such as ANOVA single factor. Results: K. pneumoniae exhibited positive inhibition with both the probiotic strain. On comparing the zone of inhibition of L. acidophilus and L. rhamnosus (both treated-pH adjusted and untreated), L. acidophilus had greater zone of inhibition against K. pneumoniae but concluded that statistically the values are insignificant (p>0.05). Based on antibiotic susceptibility pattern of K. pneumoniae, 63% of isolates were XDR, 3% were MDR and 34% were Non MDR Conclusions: It can be concluded that L. acidophilus and L. rhamnosus had significant inhibitory effect against K. pneumoniae in vitro and should be further studied for their human health benefit.

Absceso hepático en Cali, Colombia / Liver abscess in Cali, Colombia

INTRODUCCIÓN: El absceso hepático (AH) es el tipo mas común de abscesos viscerales. Se estima que el perfil epidemiológico de esta enfermedad ha cambiado con el aumento de la resistencia de los microorganismos y el uso de nuevos medicamentos. OBJETIVO: Describir las características demográficas y clínicas de los pacientes hospitalizados con diagnóstico de AH en un hospital universitario del suroccidente colombiano. MÉTODOS: Se realizó un estudio observacional retrospectivo, en la Fundación Valle del Lili, Cali, Colombia. Se incluyeron pacientes mayores de 18 años con diagnóstico de AH hospitalizados entre 2011-2020. RESULTADOS: Se incluyeron 182 pacientes. La mediana de edad fUe 56 años (rango intercuartílico, 45-67) y 62,1% fueron hombres. El microrganismo mas común fue Klebsiella pneumoniae (17,6%). La mayoría requirió drenaje percutáneo (58,2%). El 58,8% tuvo un absceso único y 54,4% fue manejado en cuidados intensivos. El 7,1% de los pacientes falleció. Al comparar los casos que fueron manejados en cuidados intensivos vs. aquellos que no lo fueron, hubo más hepatomegalia (28,3 vs. 11,0%, p = 0,004), derrame pleural derecho (48,5 vs. 28,1%, p = 0,010), cirugía (42,4 vs. 13,4%, p < 0,001), falla terapéutica (22,2 vs. 7,3%, p = 0,007) y muerte (12,1 vs. 1,2%, p = 0,005) en los atendidos en UCI. CONCLUSIÓN: Las Enterobacterales son la principal causa de AH en nuestra población. La mortalidad ha disminuido, pero la hospitalización en cuidados intensivos sigue siendo alta.

BACKGROUND: Liver abscess (LA) is the most common type of visceral abscess. It is estimated that the epidemiological profile of this disease has changed with the increase in resistance and the use of new drugs. AIM: To describe the demographic and clinical characteristics of hospitalized patients with a diagnosis of LA in a university hospital in the southwestern region of Colombia. METHODS: A. retrospective observational study was conducted at Fundación Valle del Lili, Cali, Colombia. Patients older than 18 years with a diagnosis of LA hospitalized between 2011-2020 were included. RESULTS: A total of 182 patients were included. The median age was 56 years (interquartile range, 45-67) and 62.1% were men. The most common microorganism was Klebsiella pneumoniae (17.6%). The majority required percutaneous drainage (58.2%). A 58.8% had a single abscess and 54.4% were treated in ICU. A 7.1% of the patients died. When comparing cases treated in the ICU vs. those who did not, there was more hepatomegaly (28.3 vs. 11.0%, p = 0.004), right pleural effusion (48.5 vs. 28.1%, p = 0.010), surgery (42.4 vs. 13.4%, p < 0.001), therapeutic failure (22.2 vs. 7.3%, p = 0.007) and death (12.1 vs. 1.2%, p = 0.005) in patients treated in ICU. CONCLUSION: Enterobacterales are the main cause of LA in our population. Mortality has decreased, but intensive care hospitalization remains high.

Construction of a risk prediction model for bloodstream infection induced by carbapenem-resistant Klebsiella pneumoniae / 中国药房

OBJECTIVE To construct a risk prediction model for bloodstream infection （BSI） induced by carbapenem-resistant Klebsiella pneumoniae （CRKP）. METHODS Retrospective analysis was conducted for clinical data from 253 patients with BSI induced by K. pneumoniae in the First Hospital of Qinhuangdao from January 2019 to June 2022. Patients admitted from January 2019 to December 2021 were selected as the model group （n＝223）， and patients admitted from January 2022 to June 2022 were selected as the validation group （n＝30）. The model group was divided into the CRKP subgroup （n＝56） and the carbapenem- sensitive K. pneumoniae （CSKP） subgroup （n＝167） based on whether CRKP was detected or not. The univariate and multivariate Logistic analyses were performed on basic information such as gender， age and comorbid underlying diseases in two subgroups of patients； independent risk factors were screened for CRKP-induced BSI， and a risk prediction model was constructed. The established model was verified with patients in the validation group as the target. RESULTS Admissioning to intensive care unit （ICU）， use of immunosuppressants， empirical use of carbapenems and empirical use of antibiotics against Gram-positive coccus were independent risk factors of CRKP-induced BSI （ORs were 3.749， 3.074， 2.909， 9.419， 95%CIs were 1.639-8.572， 1.292- 7.312， 1.180-7.717， 2.877-30.840， P＜0.05）. Based on this， a risk prediction model was established with a P value of 0.365. The AUC of the receiver operating characteristic （ROC） curve of the model was 0.848 [95%CI （0.779， 0.916）， P＜0.001]， and the critical score was 6.5. In the validation group， the overall accuracy of the prediction under the model was 86.67%， and the AUC of ROC curve was 0.926 [95%CI （0.809， 1.000]， P＜0.001]. CONCLUSIONS Admission to ICU， use of immunosuppressants， empirical use of carbapenems and empirical use of antibiotics against Gram-positive coccus are independent risk factors of CRKP- induced BSI. The CRKP-induced BSI risk prediction model based on the above factors has good prediction accuracy.

Application of multi-disciplinary team mode in prevention and control of multidrug resistant organism infection in lung transplant recipients / 器官移植

<b>Objective</b> To evaluate the effectiveness of multi-disciplinary team (MDT) mode in the prevention and control of multidrug resistant organism (MDRO) infection in lung transplant recipients. <b>Methods</b> Lung transplant recipients admitted to the hospital from 2019 to 2022 were enrolled. MDT expert group was established in January, 2020. A series of prevention and control measures were conducted. The implementation rate of MDRO prevention and control measures and the detection rate of MDRO on the environmental surface from 2020 to 2022, and the detection rate of MDRO in lung transplant recipients from 2019 to 2022 were analyzed. <b>Results</b> The overall implementation rate of MDRO prevention and control measures for medical staff was increased from 64.9% in 2020 to 91.6% in 2022, showing an increasing trend year by year (<i>P</i><0.05). The detection rate of MDRO on the environmental surface was decreased from 28% in 2020 to 9% in 2022, showing a downward trend year by year (<i>P</i><0.05). The detection rate of MDRO in lung transplant recipients was decreased from 66.7% in 2019 to 44.3% in 2022, showing a decreasing trend year by year (<i>P</i><0.001). <b>Conclusions</b> MDT mode management may enhance the implementation of MDRO prevention and control measures for medical staff, effectively reduce the infection rate of MDRO in lung transplant recipients and the detection rate of MDRO on the environmental surface, which is worthy of widespread application.

Clinical characteristics of children patients with carbapenem resistant Klebsiella pneumoniae infection and risk factors for poor prognosis / 重庆医学

Objective To analyze the clinical characteristics,drug resistance and risk factors for poor prognosis in children patients with carbapenem resistant Klebsiella pneumoniae(CRKP)infection.Methods The samples of CRKP isolated from the children inpatients in this hospital from August 5,2016 to December 31,2020 were collected.The clinical data and drug resistance of CRKP in the patients with CRKP positive were analyzed.The risk factors in the poor prognosis group and good prognosis group of children pa-tients with CRKP infection conducted the correlation analysis.Results A total of 106 strains of non-repeti-tive CRKP were collected,which were mainly isolated from the patients ≤ 1 year old.The department distri-bution was dominated by the neonatal ICU and comprehensive ICU.CRKP showed the high resistance to mul-tiple antibacterial drugs,and its resistance rates to amikacin,levofloxacin,gentamicin,ciprofloxacin,minocy-cline and chloramphenicol were less than 30％.The poor prognosis rate in the children patients with CRKP in-fection reached 27.4％.The logistic multivariate regression analysis results showed that the multiple organ dysfunction and anemia were the independent risk factors for poor prognosis in the children patients with CRKP infection(P＜0.05).Conclusion The children CRKP infection is mainly the infants ≤1 years old,and CRKP shows the high resistance to multiple antibacterial drugs,the independent risk factors of poor prognosis include the multiple organ dysfunction and anemia

Two golden hamster models of hypervirulent Klebsiella pneumoniae respiratory infection:a comparative study / 军事医学

Objective To establish two golden hamster models infected with hypervirulent Klebsiella pneumoniae via aerosolized intratracheal(i.t.)and intranasal(i.n.)inoculation,and compare their properties.Methods Golden hamsters of 4 to 5 weeks old were exposed to K.pneumoniae NTUH-K2044 via i.t.route and i.n.route respectively.The survival of these golden hamsters was observed and recorded within 14 days of infection before the 50%lethal dose(LD50),survival rate,bacterial respiratory deposition rate,lung bacterial load and histopathology of the infected golden hamsters in the two groups were detected.Results The LD50 of the i.t.route(3×104 CFU)was lower than that of the i.n.route(7×105 CFU)in golden hamsters.After 4×106 CFU NTUH-K2044 infection,the golden hamsters in the i.t.group had 96.46%of the bacteria deposited and colonized in the lung,developed lobar pneumonia and died without exception within 4 days of infection,while those in the i.n.group had 95.62%of the bacteria deposited in the mouth and nose initially before the bacteria moved down to the trachea for colonization and were cleared out gradually.This group mainly acquired bronchopneumonia with relatively mild lung lesions,with a 14-day survival rate of 70%.Conclusion Inoculation routes can make a difference to the disease type of respiratory tract infections in animal models.The i.t.route mainly causes lobar pneumonia with severe lung lesions,while the i.n.route leads to bronchopneumonia with mild lung lesions.The two animal models established above may be utilized for pathogenesis investigation and treatment efficacy evaluation of Klebsiella pneumoniae.

Clinical characteristics and prognosis of carbapenem-resistant Klebsiella pneumoniae bloodstream infection in preterm infants / 中华传染病杂志

Objective:To investigate the clinical characteristics and prognosis of bloodstream infection caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) in preterm infants, and to provide basis for early clinical diagnosis and infection control. Methods:The clinical data of infants with CRKP bloodstream infection admitted to the Preterm Infants Ward of Children′s Hospital Affiliated to Zhengzhou University from January 2015 to December 2022 were retrospectively analyzed. The risk factors for death in preterm infants caused by CRKP bloodstream infection were explored through multivariate logistic regression analysis, and the receiver operating characteristic (ROC) curve was used to analyze the clinical value of each factor on evaluating prognosis. The area under curves (AUC) of each factor in different ROC curve were compared by Delong′s test.Results:A total of 96 preterm infants with CRKP bloodstream infection were included, including 70 in the survival group and 26 in the death group. The first onset symptoms of CRKP bloodstream infection in preterm infants were persistent tachycardia (heart rate>180 per minute) (69 cases, 71.9%), fever (61 cases, 63.5%), and apnea (59 cases, 61.5%). There were 88(91.7%) cases of infection combined with septic shock, and 91(94.8%) cases required vasoactive drug support. Multivariate logistic regression analysis showed that the maximum vasoactive-inotropic score (VIS) within 48 hours of onset (odds ratio ( OR)=1.058, 95% confidence interval (95% CI) 1.022 to 1.095, P=0.001), concurrent purulent meningitis ( OR=8.029, 95% CI 1.344 to 47.972, P=0.022), and concurrent necrotizing enterocolitis (NEC) ( OR=10.881, 95% CI 1.566 to 75.580, P=0.016) were independent risk factors for death in preterm infants with CRKP bloodstream infection. The ROC curve showed that the AUCs for evaluating the prognosis of preterm infants with NEC and purulent meningitis were 0.784 and 0.711, respectively. The AUC for evaluating the prognosis of preterm infants with a maximum VIS ≥52.5 points within 48 hours of onset was 0.840, and the AUC for combining the three factors was 0.931. Compared with NEC and purulent meningitis, the AUC for combining factors was higher, the differences were statistically significant ( P=0.002, P<0.001). Conclusions:Preterm infants with CRKP bloodstream infection who have a maximum VIS ≥52.5 points within 48 hours of onset, with NEC and purulent meningitis have a higher risk of death.

Clinical characteristics of invasive Klebsiella pneumoniae liver abscess syndrome / 中华传染病杂志

Objective:To investigate the related factors and prognosis of invasive Klebsiella pneumoniae liver abscess syndrome (IKLAS). Methods:The in-patients diagnosed with Klebsiella pneumoniae liver abscess in the Department of Infectious Diseases, Huashan Hospital, Fudan University from January 2015 to February 2021 were retrospectively enrolled. The patients were divided into IKLAS group and non-IKLAS group according to whether they had IKLAS or not. The clinical data between the two groups were compared, including the prevalence of diabetes mellitus, the details of liver abscess, clinical symptoms such as fever and abdominal pain, as well as laboratory tests such as glycosylated hemoglobin and hemoglobin. Statistical analysis was performed using chi-square test or independent sample t test. Multivariate logistic regression analysis was used to analyze the factors influencing the occurrence of IKLAS. Results:A total of 75 patients with Klebsiella pneumoniae liver abscess were enrolled, including 55 patients (73.33%) in the IKLAS group and 20 patients (26.67%) in the non-IKLAS group. Fifty-two point seven three percent (29/55) of the patients had diabetes mellitus and 12.73%(7/55) of the patients had abdominal pain in the IKLAS group, which were 20.00%(4/20) and 45.00%(9/20) in the non-IKLAS group, respectively, and the differences were both statistically significant ( χ2=6.38 and 7.28, respectively, both P<0.05). Most of liver abscesses were single (50/75, 66.67%), and more likely to occur in the right liver (50/75, 66.67%). The maximum diameter of liver abscess in the IKLAS group was (4.58±2.04) cm, which was smaller than that in the non-IKLAS group ((6.49±3.11) cm), and the difference was statistically significant ( t=2.82, P=0.011). Compared with those in the non-IKLAS group, patients in the IKLAS group had higher glycosylated hemoglobin (8.69%±2.64% vs 6.18%±1.31%) and hemoglobin ((112.25±22.04) g/L vs (100.05±18.59) g/L), and the differences were both statistically significant ( t=-4.25 and -2.21, respectively, both P<0.05). The proportion of patients using antibiotics combined with abscess drainage in the IKLAS group was 38.18%(21/55), and that in the non-IKLAS group was 85.00%(17/20). The difference between the two groups was statistically significant ( χ2=12.86, P<0.001). A total of 16 patients (21 eyes) were diagnosed as endogenous Klebsiella pneumoniae endophthalmitis (EKPE), and all of them were IKLAS patients, and 14 patients underwent monocular/binocular eyeball injection and/or vitrectomy and silicone oil filling. The visual acuity of 13 patients decreased significantly. Multivariate logistic regression analysis showed that complicated with diabetes mellitus was an independent risk factor for IKLAS (odds ratio ( OR)=5.02, 95% confidence interval (95% CI) 1.01 to 25.03, P=0.049). The large diameter of liver abscess was a protective factor for IKLAS ( OR=0.64, 95% CI 0.47 to 0.86, P=0.003). Conclusions:The patients with IKLAS have less abdominal pain, and most of them complicate with diabetes mellitus. Diabetes mellitus is an independent risk factor for the occurrence of IKLAS, while the large diameter of liver abscess is a protective factor. EKPE is associated with poor visual prognosis.

Immunogenicity, protective efficacy and preliminary protective mechanism of KPC-2, a drug resistance target from Klebsiella pneumoniae / 中华微生物学和免疫学杂志

Objective:To develop a recombinant protein vaccine based on KPC-2, a drug resistance target in Klebsiella pneumoniae, and evaluate its immunogenicity, protective efficacy and mechanism in a mouse model of pneumonia. Methods:KPC-2 was expressed in Escherichia coli and purified using GST affinity chromatography. A recombinant protein vaccine was prepared with KPC-2 and used to immunize New Zealand rabbits through subcutaneous injection. Serum samples were isolated from cardiac blood and Protein G chromatography was used to purify polyclonal antibodies against KPC-2. Opsonophagocytic killing assay was used to assess the bactericidal activity of the polyclonal antibodies in vitro. Female BALB/c mice were immunized three times with the recombinant protein vaccine, and the titers of specific IgG antibodies in serum were measured by indirect ELISA. One week after the last vaccination, the mice were infected with Klebsiella pneumoniae strain SRT through tracheal intubation, and received a single intravenous dose of meropenem (0.1 mg) 1 h later. The protective efficacy of the KPC-2 recombinant protein vaccine was evaluated by comparing the survival rates, bacterial colonization and histopathological changes between vaccine group and adjuvant group as well as the survival rates between meropenem group and normal saline group. Moreover, the protective efficacy of polyclonal antibodies against KPC-2 was evaluated through passive immunization. Results:The level of specific IgG antibodies in serum was significantly higher in the vaccine group than in the adjuvant group ( t=4.325, P<0.05). The survival rate in the vaccine group was also higher than that of the adjuvant group [70% (7/10) vs 10% (1/10), P<0.05]. Furthermore, lung inflammation was less severe and bacterial burden was reduced in the vaccine group as compared with those of the control group ( t=3.127, P<0.05). Both active and passive vaccination strategies demonstrated strong protective efficacy against Klebsiella pneumoniae infection, and had a synergistic effect when used in combination with antibiotic therapy. The polyclonal antibodies against KPC-2 had bactericidal activity in vitro ( t=5.427, P<0.05). Conclusions:The prepared KPC-2 vaccine has better immunogenicity and protective efficacy. It can induce strong humoral immune responses. This study suggest that drug resistance target may be used as a candidate antigen for future vaccine development.

Establishment and evaluation of a RAA-CRISPR-Cas13a method for detecting KPC carbapenemase genes / 中华检验医学杂志

Objective:To establish a rapid and accurate method for the detection of Klebsiella pneumoniae carbapenemase (KPC) carbapenemase gene based on recombinase aided amplification (RAA)-CRISPR-Cas13a (CRISPR-Cas13a) technology. Methods:Twenty-five clinical isolates of carbapenem-resistant Klebsiella pneumoniae (CRKP) and five carbapenem-sensitive Klebsiella pneumoniae (CSKP) strains preserved in 2020-2021 in Beijing Chuiyangliu Hospital were randomly collected, and the total DNA samples of the strains was extracted. RAA primers specific for KPC DNA and CRISPR RNA (crRNA) were designed to establish a rapid and accurate method for the detection of KPC carbapenemase gene based on RAA-CRISPR-Cas13a technology. The method was evaluated by plasmids and clinical sample strains, and the detection was also performed by Quantitative real-time PCR (qPCR) method to compare the detection rate and consistency of the two methods. Results:The RAA-CRISPR-Cas13a method can detect KPC plasmids and samples with a sensitivity of 1 copy/μl, which is higher than that of qPCR (10 1 copies/μl). Among the 30 clinical strains (including 25 CRKP strains and 5 CSKP strains), 23 strains were detected to carry KPC gene by both RAA-CRISPR-Cas13a method and qPCR method, and 7 strains were not detected with KPC gene. The detection rate of KPC gene in the 25 CRKP strains was 92% (23/25). The positive coincidence rate of the two methods was 100% (23/23). Conclusions:This study combined RAA amplification technology with CRISPR-Cas13a technology to establish a rapid and accurate method for detecting KPC carbapenemase gene. The method is useful for accurate screening of KPC carbapenemase-producing strains. It has a wide application prospect in drug resistance monitoring and infection control.

Capsular specific typing of multidrug-resistant Klebsiella pneumoniae isolated from clinical cases in Ramadi city of Iraq

Aims@#The increasing incidence of Klebsiella pneumoniae infections in the community and hospitals is a considerable health problem. This is due to the rising resistance of the bacteria to antibiotics, biofilm formation and the presence of a capsule. The aim of this study was to survey the most common capsular types in local isolates for the first time in Iraq on a molecular level. @*Methodology and results@#Seventy isolates were screened for multidrug resistance (MDR) using a standard test. Genomic DNA was extracted from all isolates and PCR was performed using a multiplex PCR assay to detect the capsular type genes for K1, K2, K5, K20, K54 and K57. Forty-eight (68.5%) isolates demonstrated resistance to at least one agent of three or more antimicrobial categories and were therefore considered as MDR isolates. Multiplex PCR showed that 16/48 (33.3%) of MDR isolates belonged to the K2 capsular type and two isolates belonged to the K57 capsular type. The other four capsular types were not detected.@*Conclusion, significance and impact of study@#The K2 capsular type was the most common capsular type among MDR K. pneumoniae isolates from urinary tract infections (UTI) in Ramadi, Iraq. Monitoring capsular type is essential in addition to monitoring antibiotic resistance, as highly resistant strains with hypervirulent types can be particularly dangerous.

Analysis of drug resistance and pathogenicity of six strains of Klebsiella pneumoniae / 安徽医科大学学报

Objective @#To investigate the drug resistance and pathogenicity of six clinical isolates of Klebsiella pneu- moniae (Kp) ，and to provide a basis for prevention and treatment of Kp infection．@*Methods @#The six strains from different hospitals were isolated ，cultured ，and identified by species-specific gene khe． Their whole genome se- quences (WGS) were obtained using next-generation sequencing technology (NGS) ．Based on the WGS，the cap- sular serotypes，sequence types (ST) and drug-resistance genes of six strains were identified．The capsular sero- type genes and virulence genes were validated or identified using PCR. Broth microdilution tests were conducted to validate their drug susceptibility，and mice were challenged with Kp aerosols by MicroSprayer aerosolizer to evaluate their pathogenicity. @*Results @# The six strains were all serotype K2 but belonged to four ST types ( ST14 ，ST65， ST700，and ST86) ，and collectively carried six virulence genes and 23 drug-resistance genes．All the six strains were resistant to ampicillin，but only one strain was multidrug-resistant．Four strains exhibited high mucoid charac- teristics．Five strains could cause mortality in mice，which were preliminary identified as high virulence strains. @*Conclusion @# For the six Kp clinical isolates from different sources，only one strain named NY 13294 is both multi- drug-resistant and highly virulent，and other four highly virulent strains are resistant to one or two types of antibiot- ics.

Drug resistance and molecular typing characteristics of Klebsiella pneumoniae in meat food and diarrhea samples in a local area / 上海预防医学

ObjectiveTo determine the drug sensitivity and molecular typing characteristics of Klebsiella pneumoniae isolated from meat and diarrhea samples in a local area. MethodsSeventy-one strains of K.pneumoniae were isolated from 118 meat food （chicken and pork） randomly sampled in the markets in Jinshan District， Shanghai， 2020‒2021， and 1 499 diarrhea samples from outpatient diarrhoea patients in hospitals in the same district. Then drug susceptibility testing was conducted by micro-broth dilution method， and sequence identity was determined by pulsed field gel electrophoresis（PFGE）. ResultsThe overall detection rate of K.pneumoniae in meat was 11.86% （14/118）， with detection rate 20.93% （9/43） in chicken and 6.67% （5/75） in pork. The difference in detection between meats was statistically significant （χ2=5.317，P<0.05）. The detection rate of K.pneumoniae in diarrhea samples was 3.80% （57/1 499）. Furthermore， the isolated strains showed the highest resistance to ampicillin at 76.06%. The multi-drug resistant strains included 5 of human origin （8.77%） and 2 of foodborne origin （14.28%）. Additionally， 1 foodborne imipenem-resistant strain was detected. A total of 71 strains of K.pneumoniae were found to have 70 banding types， with similarity ranging from 39.4% to 100%， suggesting genetic diversity. ConclusionK.pneumoniae isolated from foodborne and diarrhea samples showed multi-drug resistance in Jinshan District， . with scattered PFGE banding patterns. It is recommended to strengthen the monitoring of this pathogen in the population and animal food， and be alert to the emerging multi-drug resistant strains and risk of food chain transmission.

Analysis of Treatment of Renal Atrophy Complicated with Multi-site Carbapenem-resist-ant Klebsiella Pneumoniae Infection / 医药导报

Objective To analyze the treatment of renal atrophy combined with multi-site carbapenem-resistant Kleb-siella pneumoniae(CRKP)infection,and to provide a reference for clinical rational drug use for such diseases.Methods Based on practical experience and referring to the latest literature,clinical pharmacists participated in the treatment of a case of renal atrophy complicated with multi-site CRKP infection.Recommendations were made,including adjusting the usage and dosage of meropenem,combining with polymyxin E,and timely de-escalation treatment.Results After the physician adopted the sug-gestion and adjusted the treatment plan,the patient's symptoms and infection indicators returned to normal,and the infection was effectively controlled.Conclusion Polymyxin E sodium methanesulfonate combined with high-dose meropenem had good clini-cal efficacy in the treatment of urinary tract and bloodstream infections caused by CRKP.

Antimicrobial resistance and related risk factors of carbapenem-resistant Klebsiella pneumoniae isolated from blood / 中国感染控制杂志

Objective To explore the antimicrobial resistance of carbapenem-resistant Klebsiella pneumoniae(CRKP)isolated from blood and the related risk factors for infection in patients.Methods Clinical data of 383 KP-infected patients from whose blood Klebsiella pneumoniae(KP)were isolated during hospitalization period in a hos-pital from January 2018 to December 2021 were retrospectively analyzed.Patients were divided into CRKP group(n=114)and non-CRKP group(n=269)based on antimicrobial resistance.According to the prognosis,114 patients in the CRKP group were subdivided into the death group(n=30)and the survival group(n=84).General informa-tion,underlying diseases,antimicrobial use,and infection outcomes of two groups of patients were compared,and risk factors for infection and death after infection were analyzed.Results The resistance rates of KP to tigecycline and compound sulfamethoxazole showed upward trends,with statistically significant differences(both P=0.008).The CRKP group had higher resistance rates to amikacin,aztreonam,compound sulfamethoxazole,ciprofloxacin,cefepime,cefoperazone/sulbactam,piperacillin/tazobactam,tigecycline,ceftazidime,tobramycin,and levofloxacin,as well as higher in-hospital mortality than the non-CRKP group,with statistically significant differences(all P＜0.05).Acute pancreatitis prior to infection(OR=16.564,P＜0.001),hypoalbuminemia(OR=8.588,P＜0.001),stay in in-tensive care unit prior to infection(OR=2.733,P=0.017),blood transfusion(OR=3.968,P=0.001),broncho-scopy(OR=5.194,P=0.014),surgery within 30 days prior to infection(OR=2.603,P=0.010),and treatment with carbapenems(OR=2.663,P=0.011)were independent risk factors for the development of CRKP blood-stream infection(BSI).Cardiac insufficiency before infection(OR=11.094,P=0.001),combined with pulmonary infection(OR=20.801,P=0.010),septic shock(OR=9.783,P=0.002),disturbance of consciousness(OR=11.648,P=0.001),and receiving glucocorticoid treatment(OR=5.333,P=0.018)were independent risk factors for mortality in patients with CRKP BSI.Conclusion The resistance rate of KP from BSI to tigecycline and com-pound sulfamethoxazole presents upward trend.Underlying diseases,invasive procedures,and carbapenem treat-ment are closely related to CRKP BSI.Cardiac insufficiency,pulmonary infection,septic shock,disturbance of con-sciousness,and glucocorticoid treatment can lead to death of patients with CRKP BSI.

Influencing factors for intestinal colonization and secondary infection of CRKP in neonates / 中国感染控制杂志

Objective To analyze the influencing factors for intestinal colonization and secondary infection of car-bapenem-resistant Klebsiella pneumoniae(CRKP)in neonates,and provide a basis for formulating prevention and control strategies for CRKP infection.Methods Neonates who were admitted to the neonatal ward of a hospital from January 2021 to October 2022 were selected as the study subjects,and the first screening of CRKP was con-ducted within 48 hours after admission.In addition,active anal swab screening for carbapenem-resistant Ente-robacterales(CRE)was performed weekly during hospitalization,and the infection status of CRKP strains was mo-nitored.Clinical data of neonates in the colonization group,non-colonization group,and infection group were ana-lyzed.Intestinal colonized strains and the non-repetitive CRKP strains isolated from clinical specimens of neonates with secondary infection after colonization were performed carbapenemase gene detection,multilocus sequence ty-ping(MLST)and pulsed-field gel electrophoresis(PFGE)analysis.Results A total of 1 438 neonates were active-ly screened for CRE,174 were CRKP positive,CRKP colonization rate was 12.1％.Among 174 neonates,35 were with secondary infection,with the incidence of 20.1％.The independent risk factors for neonatal CRKP intestinal colonization were cesarean section(OR=2.050,95％CI:1.200-3.504,P=0.009),use of cephalosporins(OR=1.889,95％CI:1.086-3.288,P=0.024),nasogastric tube feeding(OR=2.317,95％CI:1.155-4.647,P=0.018).Protective factors were breast-feeding(OR=0.506,95％CI:0.284-0.901,P=0.021),oral probiotics(OR=0.307,95％CI:0.147-0.643,P=0.002),and enema(OR=0.334,95％CI:0.171-0.656,P=0.001).Independent risk factors for secondary infection after intestinal colonization of neonatal CRKP were carbapenem anti-biotic use(OR=19.869,95％CI:1.778-222.029,P=0.015)and prolonged hospital stay(OR=1.118,95％CI:1.082-1.157,P＜0.001).The detection results of drug resistance genes showed that carbapenemase-producing genes of CRKP strains were all blaKPC-2,all belonged to type ST11.Homologous analysis showed that intestinal CRKP colonization was highly homologous with the secondary infection strains after colonization.Conclusion CRKP intestinal colonization during neonatal hospitalization may increase the risk of CRKP infection.Risk and pro-tective factors of neonatal intestinal colonization and secondary infections after colonization should be paid attention,and corresponding preventive and control measures should be taken,so as to reduce the occurrence and transmission CRKP healthcare-associated infection.

Advances in the treatment of KPC-producing Klebsiella pneumoniae infec-tion / 中国感染控制杂志

In recent years,the isolation rate of carbapenem-resistant Klebsiella pneunoniae(CRKP)in China has increased year by year.Due to its multidrug resistance and high mortality in patients,CRKP brings severe challen-ges to the clinical treatment.The major mechanism of drug resistance in CRKP is the production of carbapenemases,with Ambler A,B,and D being the common types while Ambler type C comparativly rare.Klebsiella pneumoniae carbapenemase(KPC)is the most common carbapenemase,which belongs to type A.KPC-producing Klebsiella pneumoniae(KPC-KP)widely spreads in the world,with very limited number of effective clinical drugs.In this re-view,advances in the treatment KPC-KP were summarized to provide reference for clinical treatment.

Investigation and control of a suspected outbreak of carbapenem-resistant Klebsiella pneumoniae bloodstream infection in patients with hematologi-cal tumors / 中国感染控制杂志

Objective To investigate a suspected outbreak of carbapenem-resistant Klebsiella pneumoniae(CRKP)healthcare-associated bloodstream infection(HA-BSI),provide reference for effective control of CRKP in-fection.Methods The characteristics of CRKP infected patients and the risk factors for the event transmission in an adult hematology department of a teaching hospital in June 2022 were obtained by field epidemiological investigation.The specimens of environmental target strains were co-llected by blood nutrient agar inoculation,the removal status of environmental microorganisms and the effect of infection control after implementing control measures were com-pared.Results There were a total of 6 cases of CRKP HA-BSI,with an attacking rate of 1.29％(6/464),which was significantly higher than 0 during the same period in 2021,and difference was statistically significant(P=0.011).In environmental hygiene monitoring,the detection rate of CRKP was 2.27％(1/44),which was from the surface of bed curtain in the living unit of infected patients,homology analysis with CRKP detected from 2 patients revealed that the 16s RNA of 3 CRKP strains was completely identical,with a similarity of 100％.Seven house-keeping genes of 3 CRKP strains were all identical and belonged to the ST11 type.Comprehensive control measures were taken:appropriate closure of the ward,centralized isolation of patients,terminal disinfection of the ward,reg-ular health care workers and relative restriction of their activity areas.After the measures were taken,the qualified rate of microbial colony count in the ward increased compared to before taking the measures(2.27％vs 68.89％,P＜0.001),with a statistically significant difference,there were no more CRKP infected cases after the intervention,indicating that the control measures were effective.Conclusion This outbreak was caused by ST11 type of common CRKP in China,and laminar bed curtains are carriers of pathogen transmission.It is speculated that non-standard cleaning and disinfection,as well as inadequate implementation of hand hygiene are the main causes for transmis-sion.Adopting an appropriate strategy of closing the ward and concentrating patient isolation can quickly and effec-tively prevent the transmission of the event.