Vitamin D attenuates biofilm-associated infections via immunomodulation and cathelicidin expression: a narrative review.

INTRODUCTION: Infections are becoming more difficult to treat, at least partly on account of microbes that produce biofilms. Reports suggest that decreased levels of antimicrobial peptides like cathelicidin, elevated levels of inflammatory cytokines, and biofilm formation are all associated with vitamin D deficiency, making vitamin D - deficient individuals more susceptible to infection. Infections attributable to biofilm-producing microbes can be managed by adjuvant therapy with vitamin D because of its immunomodulatory role, particularly because of the ability of vitamin D-pathway to induce the antimicrobial peptides like cathelicidin and decrease proinflammatory cytokines. AREAS COVERED: This narrative review covers biofilm formation, infections associated with biofilm due to vitamin D deficiency, putative role of vitamin D in host protection and the effect of vitamin D supplementation in biofilm-associated infections. A comprehensive literature search in PubMed and Google Scholar utilizing suitable keywords at multiple time points extracted relevant articles. EXPERT OPINION: Although vitamin D deficiency has been associated with infections by biofilm producing microbes, comprehensive clinical trials in various ethnicities are required to understand the likely relationships between vitamin D receptor gene expression, cathelicidin levels, and infection outcome. Current evidence hypothesizes that maintaining normal vitamin D level can help prevent and treat these infections.

Cryptococcal spondylodiscitis in a non-HIV patient with CD4 lymphocytopenia.

Infections that affect the intervertebral discs and vertebrae are known as spondylodiscitis. Such infections are commonly caused by pyogenic organisms, particularly Staphylococcus aureus, and hematogenous spread is the most common route. Non-pyogenic infections include Mycobacterium tuberculosis and Brucellosis. Mycotic infections are becoming more common, in line with the growing number of immunodeficiency disorders. Cryptococcus is included among these mycotic infections. We present a case of such an infection in a non-immunocompromised patient with a known history of treatment with antitubercular therapy. A 52-year-old man came to our hospital with a backache of one-month duration and progressive neurological deficits of the lower limbs of one-week duration. His imaging studies were suggestive of spondylodiscitis at the D10-11 and D11-12 levels with a left paraspinal abscess. The patient underwent anterolateral decompression, biopsy, and instrumented posterior spinal fusion. The pus grew Cryptococcus, and histopathology confirmed Cryptococcal spondylodiscitis. The patient was treated with parenteral amphotericin B and fluconazole. A mycotic infection must be considered in the differential diagnosis of infectious spondylodiscitis.

Diabetic Foot Infection with Bacteroides pyogenes.

>Diabetic foot infections are the most common serious diabetes-related complication posing significant socioeconomic burden on the health-care system. Diabetic foot microbiota consists of polymicrobial flora with predominance of Gram-negative aerobes and anaerobes. Here, we report a rare case of diabetic foot infection by Bacteroides pyogenes, an obligate Gram-negative anaerobic bacillus which is commonly encountered in polymicrobial animal bite wound infections.

Epidemiology, resistance characteristics, virulence determinants, and treatment outcomes of Staphylococcus aureus bone and joint infections: a one-year prospective study at a tertiary care hospital in India.

PURPOSE: The study was aimed to explore the differences between the Staphylococcus aureus osteosynthesis-associated infection (OAI) and non-implant related infections (NIRI) in terms of epidemiology, resistance characteristics, virulence determinants, treatment, risk factors, and outcome. METHODS: A prospective study was conducted from 2018 through 2019. The phenotypic and genotypic characterization of S. aureus, risk factors, treatment, and outcome were compared. RESULTS: A total of 60 patients were included. 50% had OAIs (70%) (p = .045). Overall, MRSA (OR 0.69; p = .020) and old age (OR 0.95; p = 0.035) were the important risk factors. Implanted patients presented with the features of chronic osteomyelitis (93.3%, p = 0.01). NIRI cases composed of only 66.7% of OM, and 55% of them were acute. OAI isolates were more frequently luk gene positives (50%) than isolates from the NIRI group (33.3%). Patients with OAI by luk positive isolates significantly had prolonged hospital stay (p = 0.043; OR-0.96, CI-0.91-1.0). Most of the NIRIs (60%) managed with antibiotics, but frequent surgical intervention (OR 10.68; p = .024) with prolonged systemic antibiotics (OR 1.07; p = .029) helped all OAIs to recover. Patients without implants were recovered in a higher number (83.3%). CONCLUSION: Our study highlighted that the differences exist between the OAI and NIRI, specifically in terms of clinical features, distribution of luk genes, treatment approach, and outcome. Risk factors for both types of infection remained the same.

Disseminated Nocardia asiatica infection in an immunocompromised individual: A rare entity needs careful vigilance.

Nocardia asteroides complex and Nocardia brasiliensis are common etiological agents of disseminated nocardiosis among immunocompromised individuals. Here we reported an uncommon case of disseminated nocardiosis with the involvement of lung, brain, soft tissue & pancreas by a rarely isolated species Nocardia asiatica in a HIV infected individual. Diagnosis was initially misinterpreted as tuberculosis based on the clinical and radiological findings. The isolate was identified to the species level with a 16S rRNA gene analysis & in vitro susceptibility was done as resistance is not uncommon among them. Clinical cure & radiological regression of lesions was observed except for brain after treatment with meropenem, amikacin & cotrimoxazole.

Typhoid spondylodiscitis mimicking tuberculosis in a teenage girl.

Salmonella Typhi cause a broad spectrum of human illnesses like gastroenteritis, typhoid fever, and bacteremia. It has also been recognized as a causative organism of osteomyelitis for more than a century but the incidence appears to be uncommon. Microbiological workup plays important role in the diagnosis of Typhoid spondylodiscitis as most of the time it mimics tuberculosis and misguide the clinician, especially in the developing world. Here, we reported an uncommon case of lumbar spondylodiscitis by Salmonella Typhi in an immunocompetent teenager, with the help of clinical, microbiological and radiological evidence. The case was managed conservatively after posterior spinal stabilization.

Unusual Severe Extra-Intestinal Manifestations of a Common Enteric Pathogen-Aeromonas Spp.

INTRODUCTION: Aeromonas spp. are halophilic, Gram-negative bacilli. They are widely distributed in the soil and aquatic environment and have been associated with various extra-intestinal infections, such as skin and soft-tissue infections, meningitis, bacteraemia etc. The most common species associated with extra-intestinal infection is Aeromonas hydrophila. AIM: To get the overview of clinical presentations, underlying predisposing factors associated with the extra-intestinal infections caused by Aeromonas species and their antimicrobial susceptibility pattern. MATERIALS AND METHODS: Extra-intestinal cases of Aeromonas spp. admitted during December 2015 to October 2016 in the tertiary care hospital of South Karnataka coastal region were analysed retrospectively. The isolates were identified by Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) VITEK®MS and antimicrobial susceptibility testing was performed by VITEK®2 system (bioMérieux, Inc., Durham, NC) respectively. Clinical manifestations and management of the cases were noted from the clinical records. Clinical and microbiological findings presented as mean±standard deviation, frequency and percentage. RESULTS: We included 26 cases in this study, from whom Aeromonas spp. were isolated alone or with another microorganism. Most widespread infection was Skin and Soft Tissue Infection (SSTI) (24, 92.3%). In 50% (12/24) cases, SSTI developed due to trauma. In 45.8% (11/24), underlying co-morbid conditions were present. The common site of infection was lower extremities (16/24, 66.7%) and 62.5% (15/24) of them presented with severe gangrene of the affected site. Other than SSTI, we encountered with two cases of keratitis and cholangitis respectively. A. hydrophila were frequently isolated species (23/26, 88.5%). The analysis of antimicrobial susceptibility showed, 13% isolates were Multidrug Resistant (MDR). Carbapenem resistance was also noted. CONCLUSION: We had isolated Aeromonas spp. from different extra-intestinal sites. Most common extra-intestinal manifestation by this organism was post-traumatic wound infection. Clinical spectrum of this infection confused the clinician with other organisms like group B Streptococcus, Clostridium spp. etc., and mislead them in empirical management. Finally with the microbiological support all the cases were treated either conservatively or in combination with surgical debridement or amputation depending on the situation.

Comparing Assay Performance of ELISA and Chemiluminescence Immunoassay in Detecting Antibodies to Hepatitis B Surface Antigen.

INTRODUCTION: Antibodies to Hepatitis B surface Antigen (Anti-HBs) levels are measured as markers for immune response to vaccination and in decision making for post-exposure prophylaxis against Hepatitis-B. Several immunoassay formats are used to measure Anti-HBs, thus carrying the possibility of variation in measured levels between different assays. This study compares the performance of Chemiluminescence Immunoassay (CLIA) against Enzyme-linked Immunosorbent Assay (ELISA) in measuring Anti-HBs titer by looking into concordance between the two test reports. AIM: To compare the agreement between ELISA and CLIA in measurement of Anti-HBs antibody titers. MATERIALS AND METHODS: This prospective comparative study conducted at Kasturba Medical College, Manipal measured consecutive serum samples (69) sent for anti-HBs levels during May-June 2016 using both CLIA (Abbott Architect) and ELISA (Bio-Rad). Anti-HBs values of ≤10mIU/ml was considered as non-protective and >10mIU/ml as protective. The agreement between the tests in classifying the antibody titers as non-protective or protective was computed using Kappa coefficient, and the difference in individual titer values between the tests compared using Bland-Altman plot on SPSS (v.15). RESULTS: Out of the 69 samples analysed, 18 samples (26.1%) were of health-care personnel and remaining of patients. Agreement between ELISA and CLIA in identifying the antibody titers as protective and non-protective were 96.5% and 90.9% respectively, resulting in an agreement of 0.84. The coefficient-of-variation of ELISA and CLIA were 74.5% and 113.1%, respectively. Three value based discordant results were noted; two samples deemed protective by ELISA were reported as non-protective by CLIA. One non-protective titer by ELISA was reported as protective by CLIA. CONCLUSION: Analytical agreement is good between the two immunoassays. However there are some discrepancies in quantitative measurement. This may have been due the variation in the standard calibrators used in each assay. Though CLIA showed more variation in the values, it has the advantage of being automated test with low turn around time. Therefore, both the test methodologies can be reliably used in place of each other for detection of Anti- HBs titer.

Clinico-microbiological study of candidemia in a tertiary care hospital of southern part of India.

BACKGROUND AND OBJECTIVES: Over the last two decades, both the incidence of nosocomial candidaemia and the proportion of blood stream infection due to Candida spp. other than Candida albicans have increased. The aims of this study was to identify different species of Candida and risk factors associated with bloodstream infection and detection of biofilm production. MATERIALS AND METHODS: This study was conducted in an 840 bedded tertiary care hospital, over a period of one year. All blood isolates received from patients during this period were screened for candidemia prospectively. Speciation was carried out by standard microbiological method. Biofilm production detection was done by Brachini et al method. RESULT: A total of 80 cases of candidemia were identified. Most important risk factor was placement of vascular access devices in all the age groups. Candida albicans accounted for 22 isolates (27.5%) whereas non-albicans Candida spp. accounted for 58 isolates (72.5%). Biofilm production was found in 31 strains (38.75%). Biofilm production was seen more in non-albicans Candidaspp. (83.87%) especially in C. tropicalis (66.67%, 8 of 12). CONCLUSIONS: Non-albicansspecies of Candida were most frequently recovered in our study. So, the epidemiology of Candida infection is changing. Non-albicans Candida spp have the capacity to produce significant amount of biofilm which may be the cause of their reduced susceptibility to antifungal agents.