Comparative Proteomic Analysis of Leptospira Interrogans Serogroup Icterohaemorrhagiae Human Vaccine Strain and Epidemic Isolate of China

Background: Leptospira interrogans serogroup Icterohaemorrhagiae is the predominant pathogen causing leptospirosis in China and is still used as the vaccine strain for the current human inactivated vaccine. Unlike the clade ST17, which is distributed worldwide, ST1 is the most prevalent in serogroup Icterohaemorrhagiae in China. Purpose and Methods: To further characterize leptospiral pathogens, isobaric tags for relative and absolute quantitation and parallel reaction monitoring were used to analyze differences at the proteomic level between serogroup Icterohaemorrhagiae vaccine strain 56001 (ST1) and circulating isolate 200502 (ST17) from different periods. Results: Two hundred and eighty-one proteins were differentially expressed between ST17 and ST1, of which 166 were upregulated (>1.2 fold change, P < 0.05) and 115 (>1.2-fold change, P < 0.05) were downregulated. Function prediction revealed that nine upregulated proteins were outer membrane proteins, including several known immunogenic and/or virulence-related proteins, such as ompL1, LipL71 and LipL41. Furthermore, important expression differences in carbohydrate, amino acid, and energy metabolism and transport proteins were identified between ST1 and ST17, suggesting that these differences may reflect metabolic diversity and the potential of the pathogens to adapt to different environments. Conclusion: In summary, our findings provide insights into better understanding the component strains of the Chinese human leptospirosis vaccine at the proteomic level. Additionally, these data facilitate evaluating the mechanisms by which pathogenic Leptospira species adapt to the host environment.

Neonatal Group B Streptococcal Meningitis: Predictors for Poor Neurologic Outcome at 18 Months

Aim To find early predictors for poor neurodevelopmental outcome after neonatal group B streptococcal meningitis. Methods We retrospectively analyzed clinical characteristics of 23 patients with neonatal group B streptococcal meningitis and their neurodevelopmental outcome at 18 months. Available group B Streptococcus strains were serotyped and their genomes characterized. Results We found several differences between patients with early- (n = 5) and late-onset (n = 18) disease. Nine children had neurologic abnormalities at 18 months and 4 had epilepsy, all of them after late-onset disease. Most important risk factors for poor outcome were impaired consciousness at admission, hemodynamic instability, seizures, or abnormal electroencephalogram during the acute illness and abnormal neurologic and ophthalmologic examination at the end of treatment, whereas abnormalities in laboratory and imaging studies were not predictive. Hypervirulent serotype III, multilocus sequence type 17 group B Streptococcus was the predominant pathogen. Conclusions Neurodevelopmental impairment after neonatal group B streptococcal meningitis is likelier in those with clinical and neurophysiological features indicating worse disease severity.

1110. In Vivo Pharmacodynamics of Vancomycin Against Staphylococci in Young Infants

Background Coagulase-negative staphylococci are the predominant pathogen causing late onset sepsis in young infants, however, the pharmacodynamic target for vancomycin therapy is unknown. This study aimed to determine the pharmacodynamic target of vancomycin in young infants with staphylococcal infections. Methods Retrospective data were collected for infants aged 0-90 days with methicillin-resistant Staphylococcus aureus (MRSA or coagulase-negative staphylococci (CoNS) bacteraemia over a 4-year period at the Royal Children’s Hospital Melbourne, Australia. Vancomycin broth microdilution minimum inhibitory concentrations (MIC) were determined. A published pharmacokinetic model was externally validated using the study dataset and a time-to-event pharmacodynamic model developed using non-linear mixed effects modelling, with the event being the first negative blood culture. Simulations were performed to determine the 24-hour trough vancomycin concentration correlating with a 90% probability target attainment (PTA) of the area under the curve in the first 24-hours (AUC0-24) exceeding the identified target. Results Thirty infants, 28 with CoNS and two with MRSA bacteraemia, who had 165 vancomycin concentrations determined were included. The vancomycin broth microdilution MIC was determined for 24 CoNS and one MRSA isolate, both with a median MIC of 1 mg/L (CoNS range 0.5 to 4). An AUC0-24 ≥3 00 mg/L·h was associated with a 7.8-fold increase in the chance of bacteriological cure for all staphylococci at any time point compared to an AUC0-24 &lt; 300 mg/L·h (hazard ratio 95% CI: 3.21-18.8). The 24-hour trough concentrations associated with a 90% PTA of achieving this target were &gt; 13-16 mg/L and &gt; 8-12 mg/L for 6 and 12-hourly dosing, respectively. Conclusion Our study found that an AUC0-24 ≥ 300 mg/L·h was associated with a 7.8-fold increase in bacteriological cure in young infants with staphylococcal bloodstream infections. Disclosures All Authors: No reported disclosures

Therapeutic Response of Community Acquired Pneumonia in Geriatrics: A Case Series from Intensive Care Unit

Community acquired pneumonia (CAP) is a common major growing challenge to elderly populations. Several aging factors, including comorbidities, nutritional status and digestive dysfunctions have been associated with increasing CAP among older persons. Furthermore, Streptococcus pneumoniae remains the most predominant pathogen in geriatrics, although multiple drug resistance (MDR) species regularly occur, particularly in severe pneumonia. Broad-spectrum antibiotics or a combination of β-lactam and fluorokuinolones, or β-lactams and macrolides serve as a promising therapy mainly in critical CAP patients. This study describes two geriatric CAP cases representing two separate treatments with widely varied results. The combination of cefoperazone sulbactam-azithromycin did not generate suitable clinical response until 7 days. As a consequence, the macrolides were replaced with amikacin and continued for 3 days. Meanwhile, the cefoperazone sulbactam-levofloxacin samples significantly improved the clinical conditions under 9 days. The selection of antibiotics with sufficient lung penetration is important in providing the effective therapy. Conversely, azithromycin resistance potentially instigates ineffectiveness, but is also recommended due to its pleiotropic effects. The benefit of this case study shows that CAP treatment among older population requires a blend of antibiotics with either a fluorokuinolone or an aminoglycoside. In both instances, azitromisin is believed to demonstrate high resistance, therefore, it is incapable in functioning as a second antibiotic component.

A study of antifungal susceptibility pattern of dermatophytes at tertiary care center

Dermatophytes are fungi that can cause infections of the skin, hair & nails due to their ability to invade keratin. Dermatophytosis is the most common superficial fungal infection worldwide; it is common in tropics and subtropical regions. It may present in epidemic proportions in areas of high humidity: The present study aimed to identify various species causing dermatophytosis & to determine the invitro susceptibility pattern against commonly used systemic antifungal agents in our tertiary care center. A total of 149 samples were collected of infected skin, hair and nails in a period of 1 year from January 2020 to December 2020. Samples were collected under aseptic condition by skin scrapping, nail and hair clipping by using scalpel or forceps. Identification of the causative pathogen was done by performing slide culture, lacto-phenol cotton blue mount, hair perforation tests and urease tests. We adopted a newly developed agar based disk diffusion assay to test susceptibility of clinically isolated dermatophytes for antifungal susceptibility testing. Microbiological investigations revealed the presence of dermatophytic fungi in 71.8% of the samples. Trichophyton rubrum was the predominant pathogen isolated. The study showed Itraconazole to be most effective antifungal drugs against dermatophytes followed by terbinafine and fluconazole.Further intensive epidemiological and invitro antifungal susceptibility studies of dermatophytes are required which will have more public health significance.

Evaluation of Leaf Spot Resistance in Wild Arachis Species of Section Arachis

Wild diploid Arachis species are potential sources of resistance to early (ELS) and late (LLS) leaf spot diseases caused by Passalora arachidicola (syn. Cercospora arachidicola Hori), and Nothopassalora personata (syn. Cercosporidium personatum (Berk. & Curt.) Deighton), respectively. Within section Arachis, limited information is available on the extent of genetic variation for resistance to these fungal pathogens. A collection of 78 accessions representing 15 wild species of Arachis section Arachis from the U.S peanut germplasm collection was evaluated for resistance to leaf spots. Screening was conducted under field (natural inoculum) conditions in Dawson, Georgia, during 2017 and 2018. Accessions differed significantly (P &lt; 0.01) for all three disease variables evaluated, which included final defoliation rating, ELS lesion counts, and LLS lesion counts. Relatively high levels of resistance were identified for both diseases, with LLS being the predominant pathogen during the two years of evaluation. This research documents new sources of resistance to leaf spot diseases selected from an environment with high inoculum pressure. The presence of ELS and LLS enabled the selection of resistant germplasm for further introgression and pre-breeding.

Misdiagnosed tuberculosis being corrected as Nocardia farcinica infection by metagenomic sequencing: a case report

Background Disseminated nocardiosis is liable to be misdiagnosed owing to the non-specific clinical manifestations and laboratory/imaging findings. Metagenomic next-generation sequencing (mNGS) is a culture-independent and rapid method for direct identification of all microorganisms in clinical specimens. Case presentation A 72-year-old man was admitted to our hospital on February 20, 2019 with a history of recurrent cough, expectoration, fever, and diarrhea since 1 month, and unconsciousness since 1 week. Contrast-enhanced magnetic resonance imaging of head showed multiple lesions in the bilateral cerebral hemispheres, brainstem, and cerebellar hemispheres. The presumptive diagnosis was disseminated tuberculosis, although all tests for mycobacterium were negative. However, the patient did not benefit from antituberculosis treatment. Repeat MRI showed multiple abnormal signals in the brain and progression of meningeal thickening. Cerebrospinal fluid and bronchoalveolar lavage fluid specimens were subsequently sent for PMSeq metagenomics sequencing; the results indicated Nocardia. farcinica as the predominant pathogen. The anti-TB treatment was stopped and the patient was prescribed sulphamethoxazole in combination with linezolid and meropenem for nocardiosis. He showed gradual neurological improvement and was transferred to Huashan Hospital. He was discharged from the hospital on April 19, 2019, but died of persistent diarrhea on May 26, 2019. Conclusions Patients with suspected nocardiosis do not always respond to conventional treatment; therefore, mNGS can facilitate diagnosis and timely treatment decision-making.

Delineating virulence of Vibrio campbellii: a predominant luminescent bacterial pathogen in Indian shrimp hatcheries

Luminescent vibriosis is a major bacterial disease in shrimp hatcheries and causes up to 100% mortality in larval stages of penaeid shrimps. We investigated the virulence factors and genetic identity of 29 luminescent Vibrio isolates from Indian shrimp hatcheries and farms, which were earlier presumed as Vibrio harveyi. Haemolysin gene-based species-specific multiplex PCR and phylogenetic analysis of rpoD and toxR identified all the isolates as V. campbellii. The gene-specific PCR revealed the presence of virulence markers involved in quorum sensing (luxM, luxS, cqsA), motility (flaA, lafA), toxin (hly, chiA, serine protease, metalloprotease), and virulence regulators (toxR, luxR) in all the isolates. The deduced amino acid sequence analysis of virulence regulator ToxR suggested four variants, namely A123Q150 (AQ; 18.9%), P123Q150 (PQ; 54.1%), A123P150 (AP; 21.6%), and P123P150 (PP; 5.4% isolates) based on amino acid at 123rd (proline or alanine) and 150th (glutamine or proline) positions. A significantly higher level of the quorum-sensing signal, autoinducer-2 (AI-2, p = 2.2e−12), and significantly reduced protease activity (p = 1.6e−07) were recorded in AP variant, whereas an inverse trend was noticed in the Q150 variants AQ and PQ. The pathogenicity study in Penaeus (Litopenaeus) vannamei juveniles revealed that all the isolates of AQ were highly pathogenic with Cox proportional hazard ratio 15.1 to 32.4 compared to P150 variants; PP (5.4 to 6.3) or AP (7.3 to 14). The correlation matrix suggested that protease, a metalloprotease, was positively correlated with pathogenicity (p > 0.05) and negatively correlated (p < 0.05) with AI-2 and AI-1. The syntenic organization of toxS-toxR-htpG operon in V. campbellii was found to be similar to pathogenic V. cholerae suggesting a similar regulatory role. The present study emphasizes that V. campbellii is a predominant pathogen in Indian shrimp hatcheries, and ToxR plays a significant role as a virulence regulator in the quorum sensing—protease pathway. Further, the study suggests that the presence of glutamine at 150th position (Q150) in ToxR is crucial for the pathogenicity of V. campbellii.

Mycetoma in West Africa

BackgroundMycetoma is a neglected disease, which is socioeconomically important, and with the possibility of permanent disability in infected persons if not treated early. This is especially true in resource-limited settings such as West Africa, where there is a lack of facilities and skilled personnel to make a definitive laboratory diagnosis. Countries in West Africa have similar climatic conditions to Sudan. The majority of patients seek medical care very late, when there is already bone involvement, resulting in amputations. This results in poor capture of the true burden of the problem in the literature.MethodsA review of the literature revealed about 2685 documented cases in West Africa from 1929 to 2020; from 15 out of 16 countries, Senegal accounted for 74.1% (1943) of cases in the subregion.ResultsThe majority of lesions were found on the foot; however, other body parts were also reported. Rural dwellers accounted for most cases. Only 547 (20.4%) cases had identified isolates reported. Actinomycetoma accounted for 47.9% of cases, eumycetoma 39.7% and unidentified pathogens 12.4%. Actinomadura pelletieri was the predominant pathogen isolated (21.4%; 117 isolates).ConclusionThere is a dire need for capacity building, provision of facility and health education to raise awareness of this debilitating disease in West Africa.

Antimicrobial Sensitivity Profile Of Uropathogens In A Macapá Laboratory, Amapá, Brazilian Amazon

Urinary tract infections (UTI) represent a worldwide health problem. Microbial resistance, due to selective antibiotic pressure, has a direct influence on the evolution and impact of these infections. The objective of this work was to identify the antimicrobial susceptibility profile of uropathogens isolated in uroculture samples from a private laboratory in the city of Macapá/AP. It is a quantitative, retrospective and cross-sectional study, using a laboratory database. Data were collected from results of urocultures with antibiogram analyzed from January to December 2019. The present study evaluated 3,510 urocultures, carried out during the study period, of which 1,269 had bacterial growth, equivalent to 36.15%. Among the positive results, we found the bacteria Escherichia coli (66.59%), Staphylococcus aureus (32.62%), mixed colonies of E. coli and S. aureus (0.47%), Staphylococcus saprophyticus (0.24%) and Serratia marcescens (0.08%). The male gender was responsible for 16.35% (n = 574) of the urocultures analyzed, while the female population was 83.65% (n = 2936). When analyzing the distribution of bacteria isolated by gender, males were considered a protective factor with 42% less chance of presenting bacteria in urine. The bacteria E. coli was the predominant pathogen in these infections in both sexes and in all age groups.