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.

"Breast abscess in a male patient due to Finegoldia magna and Bifidobacterium scardovii: An unusual entity".

Breast abscess in men is a very uncommon condition. Unlike females, breast abscesses in men are commonly caused by aerobic organisms and very rarely by anaerobes. We are hereby reporting a case of retro-areolar abscess in a male patient caused by anaerobic organisms. The culture of the drained abscess yielded the growth of Finegoldia magna, a strict anaerobic Gram-positive cocci, and Bifidobacterium scardovii, a slow growing non spore-forming anaerobic Gram-positive bacilli. Timely surgical intervention and initiation of appropriate antimicrobial therapy showed an improvement of this condition.

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.

Antimicrobial Resistance Profile and Nim Gene Detection among Bacteroides fragilis Group Isolates in a University Hospital in South India.

INTRODUCTION: Members of Bacteroides fragilis group are the most frequently isolated anaerobic pathogens in the clinical laboratory from diverse infection sites. The objective of this study was to characterize B. fragilis isolates from various clinical specimens, to analyze their susceptibility profile toward most common anti-anaerobic antimicrobials, and to study the frequency of nim gene determining resistance to nitroimidazoles. METHODS: Specimens processed for anaerobic culture between January 2013 and December 2015 were analyzed. Isolates of B. fragilis group were identified and speciated by mass spectrometry. ß-lactamase production was detected using nitrocefin disks. Agar dilution and antimicrobial gradient diffusion methods were performed to study their susceptibility profile. The isolates were screened for nim gene by conventional gel-based polymerase chain reaction. RESULTS: A total of 57 isolates of B. fragilis group were studied. The commonly isolated species was B. fragilis (73.7%), followed by Bacteroides thetaiotaomicron (8.8%), Bacteroides vulgatus (8.8%), and others. Most of the isolates were recovered from deep-seated abscesses (47.4%). All isolates were found to be ß-lactamase producers. Metronidazole (Mtz) resistance was observed in 4 (7%) isolates. Higher rate of resistance was observed toward clindamycin (31.6%). None of the isolates tested were found resistant to chloramphenicol, piperacillin-tazobactam, and meropenem. nim genes were present in 4 (11.4%) B. fragilis isolates (n = 35). CONCLUSIONS: Resistance to the most commonly used empirical anti-anaerobic drugs including Mtz was noted in the isolates of B. fragilis group. Routine anaerobic cultures when indicated and continual surveillance of antimicrobial resistance among the anaerobic bacterial pathogens is essential.

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.

Microbiological Characterization of Haemophilus influenzae Isolated from Patients with Lower Respiratory Tract Infections in a Tertiary Care Hospital, South India.

INTRODUCTION: Haemophilus influenzae is responsible for wide range of localized and invasive lower respiratory tract infections (LRTI) with the highest burden of disease in low and middle income countries. AIM: The aim of the present study was to characterize the H.influenzae isolates from suspected LRTI. MATERIALS AND METHODS: A prospective study was conducted over a period of one and half years (December 2012 to May 2014) including patients with LRTI. H.influenzae was isolated from lower respiratory specimens following standard procedures. Complete characterization of the isolates was performed by bio typing, capsular serotyping, molecular genotyping and antibiotic susceptibility testing. The predisposing factors and clinical presentation were studied in the infected patients. RESULTS: A total of 8995 samples were received during the study period, out of which growth was significantly observed in 2848 (31.7%) samples. Among the various respiratory pathogens, H.influenzae was isolated from 175 (6.14%) patients. Majority (78.9%) of the patients presented with acute exacerbations of chronic obstructive pulmonary disease. The isolates most frequently were of Biotype II (35.42%). Only four of the 50 isolates subjected to capsular serotyping were typeable and were of type b, e and f. All the 50 isolates tested were found to be non-typeable by PCR for capsular genotyping. Maximum resistance was found against ampicillin (9.71%). CONCLUSION: H.influenzae was found to be a significant cause of LRTI. Majority of the isolates were found to be non typeable strains. Non typeable H. influenzae isolates should not be neglected as they can colonize the respiratory tract in COPD patients and can lead to biofilm formation and treatment failure.