Capsular Type Research Articles

Molecular serotyping and antimicrobial susceptibility profiles of Pasteurella multocida isolated from cases of hemorrhagic septicemia in cattle from selected districts of Keffa and Bench Sheko zones, South West Ethiopia

BackgroundHemorrhagic septicemia is a highly fatal disease of cattle caused by the bacteria; Pasteurella multocida serotypes B and E in Asia and Africa respectively. Even though the capsular serotype E is considered to be the common cause of Hemorrhagic septicemia in Africa, there is not enough evidence that other serotypes are not involved. Furthermore, the serotypes currently circulating in South West Ethiopia have not been identified. This study was carried out to identify circulating capsular serotypes of Pasteurella multocida and assess its antimicrobial resistance on hemorrhagic Septicemic cattle through bacterial isolation, molecular identifications, and antimicrobial susceptibility tests in Keffa and Bench Sheko Zones of South West Ethiopia Peoples’ Regional State.ResultsThe bacteriological analysis from 45 purposively collected nasopharyngeal swab samples of hemorrhagic Septicemic cattle revealed that 12 (26.7%) isolates were identified as Pasteurella multocida. Similarly, the molecular analysis of these isolates revealed all twelve (12) isolates were confirmed to be Pasteurella multocida. On further capsular typing, serotype B (n = 5, 41.6%) and E (n = 5, 41.6%) were the confirmed circulating strains in the area while two (n = 2, 16.6%) isolates formed non-specific bands. All the Pasteurella multocida isolates were susceptible to Gentamicin (100%), Chloramphenicol (100%), Oxytetracycline (91.7%), and Streptomycin (75%). However, all the isolates showed multidrug resistance (100%), to four antibiotics “Ampicillin, Clindamycin, Penicillin-G, and Vancomycin”.ConclusionsMolecular analysis of the study isolates confirmed serotypes B and E as the etiology for Hemorrhagic septicemia in cattle in the study area. A multivalent vaccine comprising serotypes B and E is recommended to prevent outbreaks along with early treatment of suspected cases during the pyretic stage using antibiotics that are effective against the strains.

A novel depolymerase encoded by phage P5054 specifically degrades the K57-type capsular polysaccharide of Klebsiella pneumoniae

Klebsiella pneumoniae is an important pathogen, especially hypervirulent and multidrug-resistant K. pneumoniae, which are increasingly becoming a serious threat to global public health. Bacteriophages and their depolymerases are promising therapeutic alternatives to antibiotics as they are effective against hypervirulent and multidrug-resistant K. pneumoniae infections. In this study, we identified the novel depolymerase K57-Dpo8 from K. pneumoniae phage P5054. K57-Dpo8 exhibited specific depolymerase activity against K57-type capsular polysaccharide, increasing the susceptibility of K57-type K. pneumoniae strains to serum killing, macrophage phagocytosis, and improving survival rates in a murine infection model. K57-Dpo8 could inhibit biofilm formation and degrade formed biofilms. Our results provide evidence that K57-Dpo8 is not only effective for capsular typing of K57-type K. pneumoniae but also represents a promising alternative therapeutic strategy for treating K57-type K. pneumoniae infections.

Genomic and molecular characterization of a ceftazidime-avibactam resistant Klebsiella pneumoniae strain isolated from a Chinese tertiary hospital

ObjectiveThis study aims to investigate the molecular biological characteristics of a ceftazidime-avibactam resistant Klebsiella pneumoniae strain isolated from a tertiary care hospital in China.MethodsThe K. pneumoniae strain KP217360, isolated from a urine specimen at Li Huili Hospital affiliated with Ningbo University, was analyzed for antimicrobial susceptibility using the VITEK-2 Compact automated system. Antimicrobial susceptibility testing for polymyxin, tigecycline, and ceftazidime-avibactam was performed using broth microdilution according to CLSI guidelines. Whole genome sequencing was conducted using the Illumina platform, followed by comprehensive genomic analysis to characterize resistance determinants and virulence-associated genes. Experiments on conjugation were conducted to evaluate the transmissibility of the resistance plasmids. The virulence potential was evaluated through in vivo experiments using Galleria mellonella larvae as an infection model.ResultsThe K. pneumoniae KP217360 strain demonstrated extensive antimicrobial resistance, showing non-susceptibility to imipenem, ertapenem and ceftazidime-avibactam. Genomic characterization revealed the strain belonged to capsular type KL16 and harbored multiple resistance determinants, including blaCTX−M−65, blaSHV−103 and blaTEM−1, along with iron acquisition-associated virulence factors (iutA, entABCDEF, and iroN). Plasmid analysis identified three distinct plasmids, among which an IncX3-type plasmid carrying blaNDM−5 was confirmed, while the functional characteristics of the remaining two plasmids require further investigation. In the Galleria mellonella infection model, the 72-hour post-infection survival rates significantly differed among groups (P < 0.001), with NTUH-K2044, KP217360 and ATCC700603 showing survival rates of 26.7%, 56.7% and 80%, respectively. Subsequent analysis using the Pathogen Host Interactions (PHI) database identified 1,349 genes in the KP217360 strain were expressed for reduced virulence.ConclusionThis study reports the first identification of a ceftazidime-avibactam resistant K. pneumoniae ST685 strain carrying blaNDM−5 in Ningbo, Zhejiang Province, China. The findings underscore the urgent need for implementing comprehensive antimicrobial resistance surveillance programs and strengthening infection control measures to mitigate the dissemination of IncX3-type plasmids harboring blaNDM−5 in healthcare settings. Furthermore, our results emphasize the critical importance of establishing rapid enzymatic detection platforms in clinical microbiology laboratories to facilitate timely and precise therapeutic decision-making, thereby optimizing antimicrobial stewardship and improving patient outcomes.

The clinical and molecular characteristics of invasive Streptococcus agalactiae diseases in nonpregnant adults in Taiwan.

The clinical and molecular characteristics of invasive Streptococcus agalactiae diseases in nonpregnant adults in Taiwan.

Genomic Diversity, Virulome, and Resistome of Streptococcus agalactiae in Northeastern Brazil: Are Multi-Host Adapted Strains Rising?

Streptococcus agalactiae, known as group B streptococci (GBS), colonizes the digestive and genitourinary tracts and causes neonatal diseases and infections in immunocompromised and elderly individuals. GBS neonatal disease prevention includes intrapartum antibiotic prophylaxis. We characterized 101 GBS isolates obtained from patients in João Pessoa, northeastern Brazil, owing to the need to develop and implement vaccines to prevent GBS infections. Capsular types were determined using multiplex-PCR, and antibiotic susceptibility profiles were determined using disc diffusion or the gradient strip method. Clonal diversity was evaluated using pulsed-field gel electrophoresis. Fourteen selected isolates had the genome sequenced and evaluated for virulence and resistance genes. The GBS population had high clonal diversity, with serotype Ia and V prevalence. Among the sequenced isolates, we detected antibiotic resistance genes (ant(6)-Ia, catA8, ermA, ermB, lsaE, lsnuB, mefA/msrD, tetM, tetO, and tetS), several virulence genes, and mobile genetic elements integrated into the chromosome. The most frequent Sequence Type (ST) was ST144, followed by ST196, ST28, ST19, ST12, ST23, ST103, and the new ST1983 (CC103). Phylogenetically, ST103 and ST1983 were distant from the other STs. Our data revealed highly virulent GBS strains in this population and a new ST that could be related to a zoonotic origin.

Pneumococcal genotype 23B1 as a driver of increased 23B serotype carriage, penicillin non-susceptibility, and invasive disease in Belgium: a retrospective analysis.

Streptococcus pneumoniae serotype 23B, a non-vaccine serotype, has shown an increasing prevalence and penicillin non-susceptibility among carriage and invasive pneumococcal disease (IPD) isolates. Recently, a novel penicillin non-susceptible genotype has emerged, named 23B1. In the framework of the Belgian pneumococcal carriage study, we studied the prevalence of 23B0/23B1 among 586 23B strains (2016-2022) in 172 day care centers from 6- to 30-month-old children and among 130 pediatric 23B IPD isolates (2007-2021). Pneumococci were whole genome sequenced to determine the capsular polysaccharide genotype and sequence type (ST). Antimicrobial susceptibility testing determined penicillin and amoxicillin MICs, as well as resistance to co-trimoxazole and levofloxacin. 23B carriage was stable during 2016 ̶ 2022 except in the 2020-2021 winter season when it increased. The proportion of genotype 23B1 compared to 23B0 decreased from 2016 ̶ to 2022 but remained consistently higher than 23B0. In 2020-2021, an increase in the proportion of 23B1 was reflected in an overall increase in 23B carriage. All increases in 23B IPD cases were almost entirely driven by 23B1. The median penicillin MICs were significantly different for 23B0 (0.03 mg/L) and 23B1 (0.25 mg/L). In 2021, increased intermediate levofloxacin susceptibility was noted in 23B. 23B1-associated ST2372 was the most prevalent ST in carriage and IPD during 2013-2022. We show that an increase in 23B carriage among children was paralleled in pediatric IPD in Belgium, reiterating the utility of pneumococcal surveillance in the day care population. Serotype 23B is reported worldwide as an important pediatric non-PCV13 serotype with reduced penicillin susceptibility, with 23B1 as the presumed driver for the increased prevalence.IMPORTANCEDuring the COVID-19 pandemic, the 23B serotype of Streptococcus pneumoniae has increased in prevalence in healthy carriage isolates from Belgian day care centers and pediatric (younger than 18 years of age) invasive pneumococcal disease (IPD) isolates. Additionally, an increase in penicillin non-susceptibility was also observed within this serotype. Recently, a genetic variant of 23B, named 23B1, was discovered, which is known to be related to decreased penicillin susceptibility. We showed that increases in 23B prevalence in healthy carriage and IPD cases always coincided with 23B1 expansions, leading to higher penicillin non-susceptibility rates. Increases in 23B in the day care population paralleled pediatric 23B IPD increases, indicating the vital role of day care monitoring of pneumococcal carriage. Countries should stay vigilant for prevalence increases in S. pneumoniae serotype 23B, given the decreased susceptibility to penicillin and co-trimoxazole of the 23B1 variant.

Predomination of hypervirulent ST283 and genetic diversity of levofloxacin resistance in multidrug-resistant, hypervirulent Streptococcus agalactiae in Thailand.

Introduction. Group B Streptococcus (GBS) is a multi-host pathogen causing pneumonia and meningitis in humans as well as streptococcal diseases in tilapia and mastitis in cattle. Thailand has experienced a significant increase in GBS infections that greatly impact health and economics.Gap statement. The antimicrobial resistance (AMR) and genotype data of GBS in Thailand are still limited and require further study.Aim. This study aimed to describe AMR profiles and molecular characteristics, especially antimicrobial resistance genes (ARGs) and virulence factor (VF) genes of GBS in Thailand.Methodology. AMR profiles of 221 GBS isolates from humans, fish and freshwater were examined. Whole-genome sequencing of 41 representative isolates was used to investigate capsular genotypes and sequence types (STs), ARGs and VF genotypes.Results. All GBS isolates were susceptible to penicillin; the majority (99.1%) showed resistance to tetracycline. In addition, the rates of resistance to clindamycin, erythromycin and levofloxacin were 22.6%, 20.4% and 2.3%, respectively; multidrug-resistant (MDR) isolates (TE-E-CM and TE-E-CM-LVX) were 19.5%. Among 41 representative isolates, the dominant types were capsular genotype III (63.4%) and ST283 (43.9%). ARGs associated with resistance to tetracycline (tetM, tetO and tetS), erythromycin (ermB, ermA, mefA and msrD) and clindamycin (lsaC, lsaE and lnuB) were identified. Additionally, point mutations responsible for levofloxacin resistance, S81L in GyrA, S79F/Y in ParC and H221Y in ParE, were found. The MDR isolates belonged to various STs, predominantly clustering in capsular types III (60.0%) and Ib (30.0%). The MDR-hypervirulent ST17 and ST19 harboured multiple ARGs and mutations affecting quinolone resistance. Different VF gene patterns were found among hypervirulent STs (ST12, ST17, ST19 and ST283). Notably, a unique nt deletion [c.(1013_1020)delG] in pilA was found only in ST283.Conclusion. This study elucidated significant antimicrobial characteristics of a substantial number of GBS in Thailand. Moreover, the distribution of the hypervirulent ST283 and the genotypes of MDR-hypervirulent GBS were first described.

ST11 Carbapenem-Resistant Klebsiella pneumoniae Clone Harboring Capsular Type KL25 became the primarily prevalent capsular serotypes in a Tertiary Teaching Hospital in China.

ST11 Carbapenem-Resistant Klebsiella pneumoniae Clone Harboring Capsular Type KL25 became the primarily prevalent capsular serotypes in a Tertiary Teaching Hospital in China.

Capsular Typing and Molecular Characterization of Streptococcus agalactiae Strains Isolated From Bovine Mastitis in Iran.

Streptococcus agalactiae infections may cause clinical or subclinical mastitis in dairy cows by invading the mammary gland. This research included the isolation of 29 strains of S. agalactiae from 425 milk samples obtained from cows affected by clinical mastitis in Chaharmahal and Bakhtiari province, Iran. The antimicrobial sensitivity of S. agalactiae strains was determined using 16 antibiotics from seven different classes. The epidemiological spread of S. agalactiae was determined by identifying the serotypes of isolates using multiplex PCR. In addition, the presence of antibiotic-resistance genes and virulence genes were investigated to infer the pathogenicity and antibiotic resistance of S. agalactiae using the multiplex PCR method. A total of 29 strains of S. agalactiae, which constitute 6.82% of the samples, were identified based on phenotypic traits, biochemical properties and dltR gene amplification. Multiplex serotype polymerase chain reaction study showed that most of the isolates belonged to Type III serotype. Phenotypically, 100% of the isolated strains were resistant to tetracycline and penicillin. The frequency of resistance to beta-lactams (penicillin and amoxicillin) was 100% and 82.75%. tetM, tetO and tetT genes, responsible for resistance to tetracyclines, were found in all samples, corresponding to the drug-resistant phenotype. Among the genes related to the virulence factor, 100% of the isolates had the dlts gene. The examination of virulence genes revealed that the majority of isolates included the cfb, pavA and scPb genes. This data has the potential to assist in the prevention and management of mastitis and enhance our comprehension of epidemiological patterns in dairy cows affected by S. agalactiae in Chaharmahal and Bakhtiari province.

Nasopharyngeal carriage of Staphylococcus aureus in a rural population, Sierra Leone.

Nasopharyngeal carriage of Staphylococcus aureus in a rural population, Sierra Leone.

Incomplete lytic cycle of a widespread Bacteroides bacteriophage leads to the formation of defective viral particles.

Advances in metagenomics have led to the identification of new intestinal temperate bacteriophages. However, their experimental characterization remains challenging due to a limited understanding of their lysogenic-lytic cycle and the common lack of plaque formation in vitro. In this study, we investigated the hankyphage, a widespread transposable phage of prominent Bacteroides symbionts. Hankyphages spontaneously produced virions in laboratory conditions even in the absence of inducer, but virions did not show any evidence of infectivity. To increase virion production and raise the chances of observing infection events, we identified a master repressor of the hankyphage lytic cycle, RepCHP, whose silencing amplified hankyphage gene expression, andenhanced replicative transposition and virion production. However, attempts to infect or lysogenize new host cells with different capsular types remained unsuccessful. Transmission electron microscopy and capsid DNA sequencing revealed an abnormal virion morphology and incomplete DNA packaging of the hankyphage, suggesting that it cannot complete its assembly in laboratory conditions for reasons that are yet to be identified. Still, metavirome and phylogenetic analyses were suggestive of hankyphage horizontal transmission. We could also detect the activity of diversity-generating retroelements (DGRs) that mutagenize the hankyphage tail fiber, and likely contribute to its broad host range. This study sheds light on the life cycle of this abundant intestinal bacteriophage and highlights important gaps in our understanding of the factors required for the completion of its life cycle. Elucidating this puzzle will be critical to gain a better understanding of the hankyphage biology and ecological role.

Characteristic profiles of molecular types, antibiotic resistance, antibiotic resistance genes, and virulence genes of Staphylococcus aureus isolates from caprine mastitis in China.

Staphylococcus aureus is a significant pathogen in dairy animals, particularly when it infects the mammary gland; however, its prevalence among dairy goats in China remains poorly understood. This study aimed to investigate the distribution and characteristics of S. aureus isolates in dairy goats across China. A total of 515 milk samples were collected from goats diagnosed with mastitis in 14 provinces. These samples underwent bacterial isolation and identification, capsular polysaccharides typing, spa typing, antimicrobial susceptibility testing, and assessment of antimicrobial resistance and virulence gene. The findings revealed the isolation of 61 S. aureus strains. The highest prevalence rate was recorded in 2018, at 20.4% (11 out of 54 samples), while the lowest prevalence rate was noted in 2023, at 5.2% (3 out of 58 samples). Among the five regions studied, southern China exhibited the highest prevalence rate of 17.5% (10 out of 57 samples), whereas northeastern China showed the lowest rate at 8.2% (8 out of 97 samples). Capsular polysaccharide type 5 emerged as the most prevalent, accounting for 52.5%, and spa type t521 was identified most frequently, at 19.7%. Notably, 52 isolates (85.2%) demonstrated multidrug resistance, displaying resistance to three or more antibiotics. The resistance rates of S. aureus isolates were significantly high to penicillin (95.1%), followed by enrofloxacin (82.0%), kanamycin (78.7%), and levofloxacin (77.0%). Trimethoprim-sulfamethoxazole exhibited the lowest resistance rate at 11.5%. Resistance rates varied across the five different regions. Additionally, eight genes associated with resistance to six classes of antimicrobials were detected, with the blaZ gene (93.4%) being the most prevalent at 93.4%. Furthermore, nine virulence-associated genes were identified, with clfA being the most common virulence gene, present in all isolates. In conclusion, most S. aureus isolates were multiresistant with diverse resistance patterns. Those diverse antimicrobial resistance profiles associated with corresponding resistance genes (p < 0.05) were reported for the first time in S. aureus from caprine mastitis. Sulfonamides could be prioritized preferentially for the treatment of S. aureus mastitis.

Exploring the clinical outcomes and molecular characteristics of Acinetobacter baumannii bloodstream infections: a study of sequence types, capsular types, and drug resistance in China.

Bloodstream infections (BSIs) caused by Acinetobacter baumannii have been associated with high mortality. To improve the outcomes of patients, this study explored the clinical characteristics and outcomes of patients with BSIs, as well as the phenotypic and genomic characteristics of these isolates. A retrospective cohort study was conducted involving A. baumannii BSIs cases from 2020 to 2023 in a tertiary hospital. The clinical characteristics of all A. baumannii isolates were evaluated. Virulence phenotypes of all isolates were evaluated using the growth curve, biofilm-forming assay, antiserum complement killing, and G.mellonella killing assay. Furthermore, whole-genome sequencing (WGS) was utilized to analyze genomic characteristics. The 30-day mortality rate of 67 patients with BSIs was 55.22%. Patients in the death group had significantly lower platelet counts and higher CRP levels than those in the survival group. Additionally, higher rates of antibiotic use (≥2 classes) and greater carbapenem exposure were observed. Among the isolates, CRAb accounted for 80.6%, ST2 accounted for 76.12%, and KL2/3/7/77/160 accounted for 65.67%. The predominant KL type was KL3, found in 19.4% of the isolates. All ST2 and KL2/3/7/77/160 isolates were CRAb. Among the isolates, 90.7% of the CRAb isolates coharbored blaOXA-23 and blaOXA-66 , while one coharbored blaNDM-1 and blaOXA-23 . Compared with non-ST2 and non KL2/3/7/77/160 infections, ST2 and KL2/3/7/77/160 infections had higher mortality rates (66.0% vs. 23.5%, P=0.002; 65.90% vs. 34.78%, P=0.015). Patients with ST2 and KL2/3/7/77/160 infections underwent more invasive procedures, received two or more antibiotics and carbapenem therapy before isolation, and had lower serum albumin levels. These isolates exhibited significantly higher resistance to antimicrobial agents. No significant differences in virulence phenotypes were observed between the two groups, except for biofilm formation between the ST2 and non-ST2 groups (P=0.002). However, these isolates harbored more virulence genes related to iron uptake and biofilm formation. The mortality rate associated with BSIs caused by A. baumannii is high. It is of great significance for clinicians to pay attention to the risk factors of the clinical characteristics of patients and to identify the ST and KL types of the strains causing the infection at an early stage.

Emergence of hemorrhagic septicemia caused by MLST type ST64 Pasteurella multocida in a European fallow deer population in Hungary.

A sudden mass mortality involving 44 fallow deer (Dama dama) occurred in September 2020 at a game management area near Budapest, Hungary. The die-off affected both sexes and all age classes equally. On postmortem examination of 2 subadults and 1 fawn, we found average body condition, diffuse subcutaneous edema, swelling of peripheral lymph nodes, marked hemorrhages in lymph nodes along the esophagus and trachea, and left ventricular dilation. We isolated Pasteurella-like colonies from spleen, liver, small intestine, lung, and brain samples of 7 animals, and identified them as P. multocida serotype B:2 by amplifying kmt1, toxA, and hyaC-hyaD genes, capsular typing by PCR, and serotyping by agar gel diffusion precipitation test, which established the diagnosis of hemorrhagic septicemia as the cause of the outbreak. By further analysis, we determined that all of our P. multocida isolates encoded ptfA, fimA, hsf-2, nanH, hgbA, and pfhA, but we did not detect genes encoding toxA, hsf-1, tbpA, or tadD. We identified our strains by RIRDC MLST as sequence type (ST)122, characteristic for strains causing hemorrhagic septicemia, while using multi-host MLST analysis we assigned these strains to ST64 clustering with P. multocida strains from the 2015 hemorrhagic septicemia outbreak of saiga antelopes in Kazakhstan. We concluded that increased population density and aggregation due to limited drinking water availability played a role in initiating the outbreak.

Development of a lytic bacteriophage BPK01 impregnated biopolymer (chitosan) hydrogel for combating high-risk strains of carbapenem resistant Klebsiella pneumoniae (CRKP) pathogens- in vitro and in vivo evaluation.

Development of a lytic bacteriophage BPK01 impregnated biopolymer (chitosan) hydrogel for combating high-risk strains of carbapenem resistant Klebsiella pneumoniae (CRKP) pathogens- in vitro and in vivo evaluation.

Diversity of hypervirulent Klebsiella pneumoniae clones causing cryptogenic liver abscesses and metastatic complications in Argentina.

Diversity of hypervirulent Klebsiella pneumoniae clones causing cryptogenic liver abscesses and metastatic complications in Argentina.

Isolation, Characterization, and Anti-Biofilm Activity of a Novel Kaypoctavirus Against K24 Capsular Type, Multidrug-Resistant Klebsiella pneumoniae Clinical Isolates.

Background/Objectives: The significant outbreak of multidrug-resistant Klebsiella pneumoniae has emerged as a primary global concern associated with high morbidity and mortality rates. Certain strains of K. pneumoniae are highly resistant to most antibiotics available in clinical practice, exacerbating the challenge of bacterial infections. Methods: Phage vB_KpnP_PW7 (vKPPW7) was isolated and characterized. Its morphology, stability, adsorption rate, one-step growth curve, lytic activity, whole-genome sequence analysis, and antibacterial and antibiofilm activities were evaluated. Results: The virulent phage has a 73,658 bp linear dsDNA genome and was classified as a new species of the genus Kaypoctavirus, subfamily Enquatrovirinae, and family Schitoviridae. Phage vKPPW7 has a high adsorption rate, a short latent period, and a large burst size. The phage showed activity against 18 K. pneumoniae isolates with the K24 capsular type but was unable to lyse K. pneumoniae isolates whose capsular type was not classified as K24. Additionally, phage vKPPW7 demonstrated strong stability across various temperatures and pH values. The phage exhibited antibacterial activity, and scanning electron microscopy (SEM) confirmed its ability to lyse MDR K. pneumoniae with the K24 capsular type. Furthermore, phage vKPPW7 effectively removed preformed biofilm and prevented biofilm formation, resulting in reduced biofilm biomass and biofilm viability compared to controls. The architecture of phage-treated biofilms was confirmed under SEM. Conclusions: These findings suggest that phage vKPPW7 holds promise for development as a therapeutic or biocontrol agent.

P-133. Klebsiella pneumoniae liver abscess as the herald of underlying colon neoplasm

Abstract Background Klebsiella pneumoniae liver abscess (KPLA) is an endemic disease in Eastern Asia, especially Taiwan. Hypervirulent K. pneumoniae strain in the gut is able to translocate across the colonic mucosal defects to the portal system, resulting in subsequent liver abscess. Occult colon cancer in patients with KPLA has been described in several case series. However, data regarding colonoscopic findings in patients with KPLA in Taiwan have not been investigated. We aimed to investigate whether the diagnosis of KPLA serves as a marker of underlying colorectal neoplasm. Methods Consecutive patients with KPLA in Taipei Veterans General Hospital from April 2011 to January 2024 were included in this retrospective study. Clinical data were collected and colonscopy was recommended within 6 months of diagnosis of KPLA according to the patient’s will. Hypervirulent strains were defined as those with rmpA or rmpA2. In patients receiving colonoscopy, we determined the risk factors of underlying colon adenoma/adenocarcinoma using a logistic regression analysis. Results A total of 491 unique KPLA episode was collected during the study period. Most of the available strains (401 of 422, 95%) were hypervirulent strains, and most of them (339 of 422) belonged to capsular type K1 or K2. One hundred and thirteen patients (23%) had undergone colonoscopy within six months of diagnosis of KPLA. Clinical characteristics were similar between patients who had undergone colonoscopy or not. The findings of colonoscopy showed that 48 patients had adenomas (42.5%) and 12 patients had adenocarcinoma (10.6%). Patients with colon adenoma/adenocarcinoma had a higher proportion of age over 50 years (90% versus 62.3%, P&amp;lt; 0.001) and female (45% versus 26.4%, P=0.04), compared with patients without colon adenoma/adenocarcinoma. The proportion of hypervirulent strains and the distribution of capsular types were similar between the 2 groups. In multivariate analysis, age over 50 years was the only independent risk factor for colon adenoma/adenocarcinoma (P=0.002, OR=5.14, 95% CI=1.84-14.36). Conclusion Colon adenoma and adenocarcinoma were notably common in patients with KPLA. We recommended colonoscopy be routinely performed in patients with KPLA in the endemic area, especially for those older than 50 years old. Disclosures All Authors: No reported disclosures

P-849. Characteristics and Outcomes of Patients with Community-acquired and Nosocomial Klebsiella pneumoniae Bacteremia in a Tertiary Hospital in the Philippines

Abstract Background Klebsiella pneumoniae (KPN) bacteremia is associated with higher morbidity and mortality, but there is paucity of local data. This study describes the clinical, microbiologic profile, capsular types, and outcomes of individuals with community-acquired and nosocomial KPN bacteremia. Methods This study prospectively enrolled patients in a private tertiary hospital from January 1, 2023 to December 31, 2023. Hospitalized patients &amp;gt;/= 18 years old with documented KPN bacteremia were included in the study and isolates subjected to capsular typing. The two-tailed t test was used for continuous variables reported as mean and standard deviation whereas chi-square test was used for categorical variables reported as frequencies and percentages. Descriptive statistics were used and univariate analysis using Medcalc Statistical software. Results A total of 25 patients developed KPN bacteremia during the study period; 18 were community-acquired (CA) and 7 were nosocomial. More than half of patients were female (16/25, 64%), with median age 70 (+/- 15) years old. The most common comorbidities were hypertension (15/25, 60%), diabetes mellitus 14/25 (56%), and solid tumor (9/25, 36%). The average intensive care unit stay of 3.4 (+/- 5.9) days for CA KPN bacteremia was significantly shorter than the 13.6 (+/- 16.1) days for those with nosocomial KPN bacteremia. There was no difference in the total length of hospital stay for CA KPN bacteremia (36.7 +/- 85 days) and nosocomial KPN bacteremia (38.6 +/- 23.3 days). Wild-type KPN isolates (15/25, 83.3%) were more commonly found in CA KPN bacteremia, whereas multi-drug resistant isolates were more common for nosocomial KPN. Patients with endotracheal intubation (OR=16, 95% CI 2.2 to 118.3), positive qSOFA (OR=6.42, 95% CI 1.1 to 37.7%), identification of rmpA (OR=9.33, 95% CI 1.5 to 59.5%), and K20 capsular serotype (OR=6.0, 95% CI 1.0 to 35.9%) were more likely to have higher mortality. Conclusion In this cohort, KPN bacteremia occurred more frequently among women, and in the older age group. CA-KPN was more common than nosocomial KPN bacteremia, but the latter was associated with multi-drug resistance. Endotracheal intubation, positive qSOFA, rmpA, and K20 capsular serotypes were associated with higher mortality. Disclosures All Authors: No reported disclosures

Proinflammatory TNF Alfa TNF Beta, Interleukin 6, Anti-inflammatory Interleukin 10 Cytokines and the Associated Cytokine Imbalance in the Specific Immune Primed Rabbit Models with Streptococcus Pneumonia Serotype 1 and Serotype 6 Capsules

The capsular polysaccharide Type 1 and type 6 of the human clinical local pneumotropic isolates of Streptococcus pneumoniae were separated, characterized and purified. Then quantified to concentrations of 1 mg/ml. To be ready as immunogens they were admixed with an equal volume of lanline. These were standing as the test immunogens. The test immune system was that of rabbits. The test rabbit groups were assigned as C 1 group,C6 group and saline S control group each of five animals. The test rabbit groups C 1 and C6 were primed once through intramuscular route separately with capsule-lanoline mixtures and left for 21 days, then bleed. Sera were saved from the primed rabbits blood samples in 0.5 ml aliqoutes till use. Trachial mucosal immunoglobulin were separated, partially characterized and kept in alqoutes of 0.5 amounts in forml normal saline till use. One step sandawich eliza technique for TNF alfa, TNF beta, IL6 and IL10 were performed for both sera and mucosal globuilin of the primed rabbits and controls. The immune features of the capsule-lanline primed rabbits were found as; capsules were weak immunogen needs adjuvant in order to become good immunogen, cytokine responses were serotype dependent, mucosal cytokines have shown to be of higher levels than systemic responses, C1 was higher immune convertor than C 6, and both associated with cytokine imbalance towards pro-inflammatory cytokines.