Understanding antimicrobial susceptibility profile of Finegoldia magna: an insight to an untrodden path.

BACKGROUND: Finegoldia magna (formerly known as Peptococcus magnus or Peptostreptococcus magnus) belonging to phylum Firmicutes, class Clostridia and genus Finegoldia, is the only species known to cause infections in human beings. Amongst Gram positive anaerobic cocci, F. magna is known to be the most virulent with a high pathogenic potential. Significant upsurge in antimicrobial resistance among anaerobes has been documented by various studies. F. magna is known to be susceptible to most of the anti-anaerobic antimicrobials, however, multidrug resistant strains are being reported in literature. The present study was undertaken to highlight the role of F. magna in clinical infections and to analyze their antimicrobial susceptibility patterns. METHODS: The present study was conducted in a tertiary care teaching hospital in Southern India. 42 clinical isolates of F. magna recovered from diverse clinical infections between January 2011 to December 2015 were studied. These isolates were subjected to antimicrobial susceptibility testing against metronidazole, clindamycin, cefoxitin, penicillin, chloramphenicol and linezolid. RESULTS: Among the 42 isolates studied, majority of them were revived from diabetic foot infections (31%) followed by necrotizing fasciitis (19%) and deep-seated abscesses (19%). All the F. magna isolates showed good in-vitro activity against metronidazole, cefoxitin, linezolid and chloramphenicol. Clindamycin and penicillin resistance were observed against 9.5% and 2.4% of the isolates respectively. However, ß-lactamase activity was not detected. CONCLUSION: The antimicrobial resistance among anaerobes varies from pathogen to pathogen and region to region. Hence, a deep understanding of resistance pattern is necessary for better management of clinical infections.

Evaluation of a modified protocol that decreases the turnaround time of positive blood cultures.

BACKGROUND AND OBJECTIVES: Neonatal septicemia can be rapidly fatal if not treated promptly. A speedy laboratory diagnosis would improve the outcome. The BacT/ALERT 3D system (bioMerieux, Durham, North Carolina) is currently being used for laboratory diagnosis of blood stream infections. In the present study, a modified protocol was employed in which the broth was subcultured into two nutrient broth tubes and these tubes were used for biochemical tests and antimicrobial susceptibility testing to decrease the turnaround time. MATERIALS AND METHODS: A prospective study was conducted in the Department of Microbiology, SDM College of Medical Sciences and Hospital, Dharwad from October 2010 to July 2012 after receiving clearance from the institutional ethics committee. Automated blood cultures of 250 neonates admitted to the Neonatal Intensive Care Unit (NICU), clinically diagnosed to have septicemia, were performed using BacT/ALERT 3D. Bottles flagged positive within 72 hours of loading were processed for identification and antibiotic susceptibility testing using a modified protocol. The results were assessed for time saved in reporting in comparison with standard protocol. Student's t test was used for statistical analysis. RESULTS: Of the 250 cases studied, 117 cases yielded a positive blood culture giving a yield of 46.8%. The number of cases yielding monomicrobial growth were 73, which were included for further analysis. Of the remaining samples, 133 did not show growth, 11 were polymicrobial while 33 samples were flagged positive after 72 hours. Candida spp. grew in 34 cases, Gram negative bacilli grew in 28 cases and Gram positive cocci grew in 11 cases. In four cases, 66 hours were saved, 60 and 54 hours were saved in 18 cases each, 48 hours were saved in 27 cases, and 24 hours were saved in 6 cases. Methicillin resistant Staphylococcus aureus and Klebsiella pneumoniae were the most common isolates among Gram positive cocci and Gram negative bacilli, respectively, while C. guilliermondii was the most common Candida isolate. All Gram positive isolates were susceptible to vancomycin and linezolid. Most of the Gram negative isolates were susceptible to imipenem. CONCLUSION: This method can be employed in peripheral laboratory settings where there is no complete automation. Modification in processing blood culture can provide speedy identification and sensitivity report in blood stream infections. Time saved in reporting would play a crucial role in improving morbidity and mortality rates in neonatal septicemia.

Anaerobic Bacteria in Clinical Specimens - Frequent, But a Neglected Lot: A Five Year Experience at a Tertiary Care Hospital.

INTRODUCTION: Anaerobic bacteria which constitute a significant proportion of the normal microbiota also cause variety of infections involving various anatomic sites. Considering the tedious culture techniques with longer turnaround time, anaerobic cultures are usually neglected by clinicians and microbiologists. AIM: To study the frequency of isolation of different anaerobic bacteria from various clinical specimens. MATERIALS AND METHODS: A retrospective study to analyse the frequency of isolation of different anaerobic bacteria, was conducted over a period of five years from 2011 to 2015 including various clinical specimens submitted to anaerobic division of Microbiology laboratory. Anaerobic bacteria were isolated and identified following standard bacteriological techniques. RESULTS: Pathogenic anaerobes (n=336) were isolated from 278 (12.48%) of overall 2227 specimens processed with an average yield of 1.2 isolates. Anaerobes were isolated as polymicrobial flora with or without aerobic bacterial pathogens in 159 (57.2%) patients. Anaerobic Gram-negative bacilli (140, 41.7%) were the predominant isolates. B. fragilis group (67, 19.9%) were the most commonly isolated anaerobic pathogens. Anaerobes were predominantly isolated from deep seated abscess (23.9%). CONCLUSION: Pathogenic anaerobes were isolated from various infection sites. Unless culture and susceptibility tests are performed as a routine, true magnitude of antimicrobial resistance among anaerobic pathogens will not be known. Knowledge of the distribution of these organisms may assist in the selection of appropriate empirical therapy for anaerobic infections.