India-discovered levonadifloxacin & alalevonadifloxacin: A review on susceptibility testing methods, CLSI quality control and breakpoints along with a brief account of their emerging therapeutic profile as a novel standard-of-care.

BACKGROUND: Levonadifloxacin (intravenous) and alalevonadifloxacin (oral prodrug) are novel antibiotics based on benzoquinolizine subclass of fluoroquinolone, licensed for clinical use in India in 2019. The active moiety, levonadifloxacin, is a broad-spectrum antibiotic with a high potency against methicillin-resistant Staphylococcus. aureus, multi-drug resistant pneumococci and anaerobes. OBJECTIVE: This review, for the first time, critically analyses the antimicrobial susceptibility testing methods, Clinical Laboratory & Standards Institute (CLSI)-quality control of susceptibility testing and breakpoints of levonadifloxacin. Further, the genesis, discovery and developmental aspects as well as therapeutic profile of levonadifloxacin and alalevonadifloxacin are briefly described. CONTENTS: In order to aid the scientific and clinician communities with a single comprehensive overview on all the key aspects of levonadifloxacin and alalevonadifloxacin, the present article covers the reference MIC and disk diffusion methods for levonadifloxacin susceptibility testing that were approved by CLSI and the reference ranges for quality control strains published in the CLSI M100 document. The breakpoints of levonadifloxacin were derived in concordance to US FDA, European Committee on Antibiotic Susceptibility Testing (EUCAST) and CLSI approaches. Further, the article provides a brief account of challenges encountered during the discovery stages of levonadifloxacin and alalevonadifloxacin, activity spectrum and safety benefits accruing from structural novelty-linked mechanism of action. Further, the review also covers in vitro and in vivo activities, registrational clinical studies and patient-friendly features of levonadifloxacin/alalevonadifloxacin. Cumulatively, levonadifloxacin has a potential to offer a long awaited new standard-of-care treatment for the resistant Gram-positive bacterial infections.

In vitro activity of a novel antibacterial agent, levonadifloxacin, against clinical isolates collected in a prospective, multicentre surveillance study in India during 2016-18.

BACKGROUND: Levonadifloxacin is a novel antibiotic belonging to the benzoquinolizine subclass of fluoroquinolones with potent activity against MRSA and quinolone-resistant Staphylococcus aureus. IV levonadifloxacin and its oral prodrug alalevonadifloxacin have recently been approved in India for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) including diabetic foot infections. OBJECTIVES: To investigate the in vitro activity of levonadifloxacin against contemporary clinical isolates collected from multiple tertiary care hospitals across India in the Antimicrobial Susceptibility Profiling of Indian Resistotypes (ASPIRE) surveillance study. METHODS: A total of 1376 clinical isolates, consisting of staphylococci (n = 677), streptococci (n = 178), Enterobacterales (n = 320), Pseudomonas aeruginosa (n = 140) and Acinetobacter baumannii (n = 61), collected (2016-18) from 16 tertiary hospitals located across 12 states in India, were included in the study. The MICs of levonadifloxacin and comparator antibiotics were determined using the reference agar dilution method and broth microdilution method. RESULTS: Levonadifloxacin exhibited potent activity against MSSA (MIC50/90: 0.5/1 mg/L), MRSA (MIC50/90: 0.5/1 mg/L) and levofloxacin-resistant S. aureus (MIC50/90: 1/1 mg/L) isolates. Similarly, potent activity of levonadifloxacin was also observed against CoNS including MDR isolates (MIC50/90: 1/2 mg/L). Against Streptococcus pneumoniae, levonadifloxacin (MIC50/90: 0.5/0.5 mg/L) showed superior activity compared with levofloxacin (MIC50/90: 1/2 mg/L). Among levofloxacin-susceptible Enterobacterales, 80.6% of isolates were inhibited at ≤2 mg/L levonadifloxacin. CONCLUSIONS: Levonadifloxacin displayed potent activity against contemporary MRSA and fluoroquinolone-resistant staphylococcal isolates, thus offering a valuable IV as well as an oral therapeutic option for the treatment of ABSSSIs. Furthermore, levonadifloxacin exhibited a broad-spectrum activity profile as evident from its activity against streptococci and levofloxacin-susceptible Gram-negative isolates.

Linezolid resistant coagulase negative staphylococci (LRCoNS) with novel mutations causing blood stream infections (BSI) in India.

BACKGROUND: Coagulase-negative Staphylococci (CoNS) have emerged as a major causative agent of blood-stream infections (BSI). Linezolid (LZD) is currently used for treating glycopeptide and methicillin-resistant staphylococci. It is important to understand the resistance mechanism and probable transmission of LZD resistant (LR) CoNS within the hospital. METHODS: Clinically significant LRCoNS from patients with BSI were characterized using MALDI-TOF and 16S rRNA gene sequence analysis. Antimicrobial susceptibility and MIC of vancomycin and LZD were determined. LZD resistance mechanisms using PCR for the cfr gene and mutation in the V domain of the 23S rRNA gene were studied. RESULTS: The MIC of LZD ranged from 8 to 32 µg/ml. LR was observed in three different CoNS species from diverse locations within the hospital. The cfr gene was identified in all the isolates. Sequence analysis of V domain region of 23S rRNA gene confirmed mutation in single copy among 12/15 isolates with novel mutations: G2614 T and C2384T. All infections were nosocomially acquired and LZD resistance was emerging in the absence of prior LZD use. Horizontal spread of resistant isolates and cfr gene among diverse species were the probable mechanisms of transmission. CONCLUSION: The study highlights the novel mutations associated with LRCoNS and the importance of surveillance & transmission pathway within the hospital. It also systematically discusses the published information on LRCoNS.

Direct testing by VITEK® 2: A dependable method to reduce turnaround time in Gram-negative bloodstream infections.

CONTEXT: Bloodstream infections pose a major health-care burden worldwide. Routine microbiological methods are time-consuming, thereby delaying appropriate treatment. AIMS: The aim of this study is to evaluate the method of direct testing of identification (ID) and antimicrobial susceptibility testing (AST) of positive blood culture bottles by VITEK®2. SETTINGS AND DESIGN: This was a prospective study at a tertiary level hospital. SUBJECTS AND METHODS: One hundred positive BACTEC blood culture bottles with monomicrobial Gram-negative organisms on microscopy were tested in parallel by direct ID/AST as well as conventional method. Results obtained by two methods were compared in terms of ID/AST and turnaround time (TAT). RESULTS: Of the 100 isolates tested, only one was misidentified by the direct method and there was no unidentified isolate. The AST results demonstrated 99.74% categorical and 99.65% essential agreement. Of 1144 organism-antibiotic combinations, there were 0.44% major error, no very major error, or minor error observed. CONCLUSIONS: While conventional method is the gold standard, the direct ID/AST methods have demonstrated that it can be successfully utilized to decrease TAT to the final results by 18-24 h, without sacrificing test accuracy. This technique will help to tailor antimicrobial therapy, thereby reducing patient morbidity, mortality, and antibiotic resistance, as well.

Pulmonary Cryptococcosis in HIV- sero-negative patients: case series from India.

Pulmonary cryptococcosis is likely to be misdiagnosed due to relatively non-specific clinical and radiological features. It is more frequently associated with immuno-suppressed conditions especially acquired immuno-deficiency syndrome (AIDS) and pulmonary tuberculosis (PTB). Four cases of pulmonary cryptococcosis were diagnosed over a period of eleven years. All patients in this case series were human immune-deficiency virus (HIV)-negative. The predisposing factors in these patients were diabetes mellitus (DM), acute lymphoblastic leukaemia (ALL), post-partum and pregnancy in one each of the patients. Relapse was seen in two cases. All the patients survived due to strict follow-up. Pulmonary cryptococcosis is common in non-AIDS patients and it warrants rapid diagnosis, treatment and follow-up to prevent relapse.

Herpes simplex virus 2 : a boon to develop other sexually transmitted infections.

Genital herpes is one of the most common sexually transmitted infections. Though, mostly asymptomatic, it acts as a potential risk factor for acquisition of other sexually transmitted infections (STIs). The present study was undertaken to know sero-prevalence of herpes simplex virus 2 (HSV2), syphilis and HIV among STI clinic attendees and to detect the diagnostic utility of HSV2 IgM antibodies. The study group included 170 individuals attending STI clinic irrespective of their presenting complaints. Their sera were subjected to enzyme-linked immunosorbent assay for detection of HSV2 IgM antibodies. The samples were also screened for HIV and syphilis. Twenty-seven (15.88%) out of 170 persons were found to be seropositive for HSV2 IgM antibodies. Syphilis was detected in 13 individuals (7.65%). Twelve individuals (7.06%) were found to be reactive for anti HIV I antibodies. Ten of the genital herpes patients (37.04%), did not have any complaint of genital ulcer. Eight HSV2 patients (29.63%) had coinfection with HIV I, 6 (22.22%) with syphilis and 2 (07.41%) had co-infection with both HIV and syphilis. A significant proportion of the patients with genital herpes presented without the history of genital ulcers. Thus, its detection and treatment among asymptomatic patients is significant so as to reduce its transmission and other STIs.