Ujjwayini Ray

Antimicrobial Resistance, Virulence Profiles and Molecular Subtypes of Salmonella enterica Serovars Typhi and Paratyphi A Blood Isolates from Kolkata, India during 2009-2013

Enteric fever, caused by Salmonella enterica, remains an unresolved public health problem in India and antimicrobial therapy is the main mode of treatment. The objective of this study was to characterize the Salmonella enterica isolates from Kolkata with respect to their antimicrobial resistance (AMR), virulence profiles and molecular subtypes. Salmonella enterica blood isolates were collected from clinically suspected enteric fever patients attending various hospitals in Kolkata, India from January 2009 to June 2013 and were tested for AMR profiles by standard protocols; for resistance gene transfer by conjugation; for resistance and virulence genes profiles by PCR; and for molecular subtypes by Pulsed Field Gel Electrophoresis (PFGE). A total of 77 Salmonella enterica serovar Typhi (S. Typhi) and 25 Salmonella enterica serovar Paratyphi A (S. Paratyphi A) from Kolkata were included in this study. Although multidrug resistance (resistance to chloramphenicol, ampicillin, co-trimoxazole) was decreasing in S. Typhi (18.2%) and absent in S. Paratyphi A, increased resistance to fluoroquinolone, the current drug of choice, caused growing concern for typhoid treatment. A single, non-conjugative non-IncHI1 plasmid of 180 kb was found in 71.4% multidrug resistant (MDR) S. Typhi; the remaining 28.6% isolates were without plasmid. Various AMR markers (bla TEM-1, catA, sul1, sul2, dfrA15, strA-strB) and class 1 integron with dfrA7 gene were detected in MDR S. Typhi by PCR and sequencing. Most of the study isolates were likely to be virulent due to the presence of virulence markers. Major diversity was not noticed among S. Typhi and S. Paratyphi A from Kolkata by PFGE. The observed association between AMR profiles and S. Typhi pulsotypes might be useful in controlling the spread of the organism by appropriate intervention. The study reiterated the importance of continuous monitoring of AMR and molecular subtypes of Salmonella isolates from endemic regions for better understanding of the disease epidemiology.

Brain abscess due to Cladophialophora bantiana: a review of 124 cases.

Brain abscess caused by Cladophialophora bantiana is a rare disease associated with high mortality due to delay in diagnosis and absence of standardized therapy. We reviewed 124 culture proven C. bantiana brain abscess cases; 103 cases published in English literature during 1952 through 2014 and 21 unpublished cases from our reference center. The majority (57.3%) of the patients was from Asian countries especially from India (62/124, 50%). The diagnosis of the cases was delayed with mean duration 115 days after developing symptoms. The disease was nearly equally distributed in immunocompetent and immunosuppressed hosts but associated with significantly higher mortality (77.1%) in later group. Complete excision of brain lesion in immunocompetent host led to significantly better survival (43.7%). Though all commercially available antifungal drugs have been used in these patients, amphotericin B deoxycholate or lipid preparations were most commonly (62.83%) prescribed agent. None of the drugs used was found to be independently associated with improved outcome. In vitro antifungal susceptibility testing of 13 isolates of our center, demonstrated good activity to voriconazole, posaconazole, and itraconazole, but these triazoles were prescribed in only 29.2% patients. Increased awareness with early suspicion of the disease, and aggressive medical and surgical approach in treating these patients may improve the outcome.

Antimicrobial resistance and molecular subtypes of Salmonella enterica serovar Typhi isolates from Kolkata, India over a 15 years period 1998–2012

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), remains an unresolved public health problem in India. Emergence of antimicrobial resistant strains poses a great concern for typhoid treatment and influences reshaping of current S. Typhi population. We included representative S. Typhi strains (n=164) from retrospective studies, both community and hospital based, conducted at National Institute of Cholera and Enteric Diseases, Kolkata during 15 years period (1998-2012) to analyze their antimicrobial resistance (AMR) profiles, mechanism of AMR and molecular subtypes of the strains. More than 60% of the S. Typhi isolates were obtained from community based studies. During the study period, steady decline (46.4%-15.6%) in isolation of multidrug-resistant (MDR, resistant to ampicillin, chloramphenicol and co-trimoxazole) S. Typhi was noticed with parallel increase of nalidixic acid-resistant (NALR) strains (60.7%-93.8%) and ciprofloxacin resistant (CIPR) strains (0%-25%). Of 53 MDR strains, 46 (86.8%) were NALR showing decreased ciprofloxacin susceptible (DCS) (MIC for ciprofloxacin 0.12-0.5μg/ml) phenotype. Conjugative IncHI1 (230kb) and non-conjugative non-IncHI1 (180kb) plasmids were found in 23 (43.4%) and 14 (26.4%) MDR strains respectively, plasmid was absent in 16 (30.2%) MDR strains. MDR strains with or without plasmid shared the same set of resistance genes (blaTEM-1, catA1, sul1, sul2, strA and strB) and class 1 integron possessing dfrA7 gene cassette. Two S. Typhi strains harbored 50kb transferrable plasmids carrying dfrA15 and aadA1 gene cassettes in class 1 integron. The majority of the strains (135/164, 82.3%) belonged to H58 haplotype. Among the MDR isolates, fluoroquinolone resistant or combined resistant isolates (n=147), 127 (86.4%) were H58 and 20 (13.6%) belonged to non-H58. NALRS. Typhi strains with decreased susceptibility or resistance to ciprofloxacin had point mutation(s) in quinolone resistance-determining region of gyrA and parC genes. Pulsed-field gel electrophoresis showed more diversity among NALRS. Typhi than MDR strains. Results of this study generated information useful for better understanding of the disease epidemiology and its control in endemic settings.

Septic Shock in a Patient with Tubercular Liver Abscess

Tuberculosis is second only to HIV/AIDS as the greatest killer worldwide due to a single infectious agent. In 2012, 8.6 million people fell ill with tuberculosis and 1.3 million people died from the disease [1]. Mycobacterial septic shock, once considered a rare complication of miliary tuberculosis is now being increasingly recognized. Mycobacterial septic shock also referred to as sepsis tuberculosa gravissima can manifest in patients even without widespread dissemination. Mycobacterial septic shock is diagnosed in patients who present with haemodynamic features of septic shock along with clinical suspicion of tuberculosis with positive staining for acid fast bacilli and or recovery of Mycobacterium tuberculosis in culture from sputum, BAL, body fluids or tissues in the absence of a more plausible pathogen [2]. Mycobacterial septic shock carries a grave prognosis and early recognition of the entity is of utmost importance. Here we present a case of mycobacterial septic shock in a patient of chronic renal failure.

A prospective study of ventilator-associated tracheobronchitis: Incidence and etiology in intensive care unit of a tertiary care hospital

Context: Ventilator-associated tracheobronchitis (VAT) is an infective complication of mechanical ventilation and is a part of the spectrum of ventilator-associated respiratory infections. In the Intensive Care Units (ICUs), VAT is a relatively common problem but in comparison to ventilator-associated pneumonia (VAP), much less data are available on VAT and its management. Materials and Methods: Patients ventilated for more than 48 hours were screened daily for the development of VAT. Patients were followed up daily until they were extubated, died or discharged from the hospital. The patient demographics, underlying condition, causative organism and resistance patterns were observed. Results: 13.2% of patients developed VAT. The majority patients who developed VAT had underlying neurological problems. The mean time to develop VAT from the time of mechanical ventilation was 7.3 days and from time of ICU admission was 10 days, respectively. Multidrug-resistant (MDR) Acinetobacter sp. and Pseudomonas aeruginosa were the most frequently isolated organisms. Conclusions: VAT is a common healthcare-associated infection caused mostly by MDR Gram-negative bacteria. Monitoring and active surveillance are required to detect VAT at the earliest to institute appropriate isolation measures and therapy.

Revisit of fluoroquinolone and azithromycin susceptibility breakpoints for Salmonella enterica serovar Typhi

In recent years, increase in occurrence of fluoroquinolone (FQ)-resistant S almonella Typhi isolates has caused considerable inconvenience in selecting appropriate antimicrobials for treatment of typhoid. The World Health Organization (WHO) recommends azithromycin for the empirical treatment option of uncomplicated typhoid. The CLSI updated the breakpoints of disc diffusion (DD) and MIC results of FQs and azithromycin for Salmonella Typhi in 2015, but DD breakpoints of ofloxacin and levofloxacin were not included. In this study, the inhibition zone diameters and MICs of nalidixic acid, ciprofloxacin, ofloxacin, levofloxacin and azithromycin were determined in Salmonella Typhi Kolkata isolates (n =146) over a 16-year period (1998 to 2013) and the data were compared with the available CLSI breakpoints. Very major error and major error (ME) of FQs were not observed in the study isolates, but the minor error of ciprofloxacin (15.8 %) and ME of azithromycin (3.5 %) exceeded the acceptable limit. A positive correlation between MICs of FQ and mutations in the quinolone-resistance-determining region (QRDR) showed the reliability of MIC results to determine FQ susceptibility of Salmonella Typhi (n =74). Isolates showing decreased ciprofloxacin susceptibility (MIC 0.125-0.5 µg  ml-1) were likely to have at least one mutation in the QRDR region. The results on DD breakpoints of ofloxacin (resistant, ≤15 mm; intermediate, 16-24 mm, and susceptible, ≥25 mm) and levofloxacin (resistant, ≤18 mm; intermediate, 19-27 mm, and susceptible, ≥28 mm) corroborated those of earlier studies. In view of the emerging FQ- and azithromycin-resistant Salmonella Typhi isolates, DD and MIC breakpoints of those antimicrobials should be revisited routinely.

Severe dengue due to secondary hemophagocytic lymphohistiocytosis: A case study

Highlights • Dengue induced Hemophagocytic lymphohistiocytosis (HLH), is a serious entity and can adversely affect the course of the infection.• HLH is a potentially life threatening disorder and early diagnosis and management is crucial for successful outcome.• A disproportionately high ferritin level should trigger investigations for HLH.

An Unusual Case of Septic Arthritis of the Hip.

Non-typhoidal Salmonella, particularly Salmonella enterica serovar typhimurium is food borne pathogen causing mild self-limiting diarrhoea in healthy adults. It can occasionally cause extraintestinal focal infection in susceptible patients. Salmonella, as the aetiological agent of osteomyelitis and septic arthritis is rare and has been mostly reported in patients with sickle cell disease or thalassaemia. We report a case of septic arthritis by Salmonellatyphimurium in an immunocompromised patient who was successfully treated following timely isolation and identification of the aetiological agent.