Brahmadathan N.K.,Microbiological Laboratory
Indian Journal of Medical Microbiology | Year: 2017
Infections due to Streptococcus pyogenes and their complications are a problem of major concern in many countries, including India. Primary prophylaxis with benzathine penicillin is the key to control and prevent sequelae such as acute rheumatic fever and rheumatic heart disease (RF/RHD) or post-streptococcal glomerulonephritis (PSGN). Non-compliance to prophylaxis due to fear of injection and anaphylaxis is major issues in RF/RHD control in India and leads to continued high prevalence of infection and post-streptococcal sequelae. Differing reports on the efficacy of two weekly, three weekly or monthly injections raise questions on the actual dosages to be administered. Availability of more effective antibiotics with better dosages has replaced the use of penicillin; hence, companies are reluctant to manufacture penicillin preparations in India. It is in this context that a concept of a Group A streptococci vaccine is looked at and whether or not a globally designed vaccine will be useful in the Indian context. Modern molecular techniques and genomic analysis of S. pyogenes have identified many molecules as vaccine candidates among which the M-protein has attracted the most attention. High diversity of M (emm) types in endemic regions raises questions about the efficacy of such a vaccine. A recent 30-valent M-protein-based vaccine that elicits antibodies to homologous as well as non-vaccine M types looks promising. This review will discuss the genomics of S. pyogenes, the various candidate vaccine molecules and highlight their efficacy in the Indian context where control of post-streptococcal sequelae remains a challenge. © 2017 Indian Journal of Medical Microbiology Published by Wolters Kluwer -Medknow.
Prabagaran S.R.,Bharathiar University |
Kalaiselvi V.,Bharathiar University |
Chandramouleeswaran N.,Bharathiar University |
Deepthi K.N.G.,Bharathiar University |
And 2 more authors.
Journal of Microbiological Methods | Year: 2017
A nested multiplex polymerase chain reaction (PCR) based diagnosis was developed for the detection of virulent Salmonella typhi in the blood specimens from patients suspected for typhoid fever. After the Widal test, two pairs of primers were used for the detection of flagellin gene (fliC) of S. typhi. Among them, those positive for fliC alone were subjected to identification of genes in Via B operon of Salmonella Pathogenesity Island (SPI-7) where four primer pairs were used to detect tviA and tviB genes. Among 250 blood samples tested, 115 were positive by fliC PCR; 22 of these were negative for tviA and tviB. Hence, the method described here can be used to diagnose the incidence of Vi-negative serovar typhi especially in endemic regions where the Vi vaccine is administered. © 2017 Elsevier B.V.
PubMed | Microbiological Laboratory and Polish National Medicines Institute
Type: Case Reports | Journal: Polski merkuriusz lekarski : organ Polskiego Towarzystwa Lekarskiego | Year: 2015
We describe a case of a life-threatening septicemia resulting from a previous dog bite wound. The isolated bacterium was Capnocytophaga canimorsus, a slow-growing Gram-negative bacillus commonly found in dog saliva. Known risk factors for invasive C. canimorsus infections are alcohol abuse, cigarette smoking, splenectomy or other forms of immunosuppression. Any clinician seeing patients with a history of a dog bite should consider this pathogen as a causative agent and take detailed history regarding exposure to animals.
Bredl S.,Redbiotec |
Bredl S.,University of Regensburg |
Plentz A.,University of Regensburg |
Wenzel J.J.,University of Regensburg |
And 3 more authors.
Journal of Clinical Virology | Year: 2011
Background: Acute parvovirus B19 (B19V) infection is characterized by high-level viremia. Antibodies against the capsid proteins VP1 and VP2 may complex with B19V-particles thereby becoming undetectable in diagnostic tests. Objectives: We intended to obtain data on the frequency of false-negative serology in acute B19V-infection. Study design: 129 plasma or serum samples of healthy blood donors and of patients with suspected B19V-infection were analyzed for B19V-DNA by qPCR and VP1/VP2-specific IgG and IgM by ELISA. Eleven of these samples were derived from four pregnant women with previous contact to B19V-infected individuals. Using acidic conditions virus/antibody-complexes were disrupted and detected by WesternLine and ELISA. Results: 83/118 samples were derived from acutely infected individuals displaying viremia (10 3-10 12geq/mL). In 24/83 viremic samples (28.9%) VP1/VP2-specific IgM and IgG were undetectable in ELISA, but could be demonstrated to be complexed with B19V-particles. Each 7/83 (8.4%) was IgM-positive/IgG-negative and IgM-negative/IgG-positive, in 45/83 samples (54.2%) IgG and IgM could be detected. 35 samples did not contain B19V-DNA; five of these were from seronegative persons. Analyzing consecutive sera derived from four pregnant women, B19V-DNA was demonstrated in 10/11 samples, B19V-specific IgG- and IgM-antibodies were detectable in 10/11 and 4/11 samples, respectively. In 2/4 women seroconversion was observed, but IgM was not detected in 50% of the samples. B19V-specific IgG but not IgM was detectable in 2/4 women. Conclusion: Acute B19V-infection cannot be diagnosed by exclusive analysis of B19V-specific antibodies. Only the combination of assays for detection of B19V-DNA and antibodies enables correct serodiagnosis. © 2011 Elsevier B.V.
Lourtet-Hascoett J.,Microbiological Laboratory |
Bicart-See A.,Microbiological Laboratory |
Felice M.P.,Microbiological Laboratory |
Giordano G.,Hopital J. Ducuing |
Bonnet E.,Infectious Diseases Mobile Unit
Diagnostic Microbiology and Infectious Disease | Year: 2015
Periprosthetic joint infections (PJIs) are frequently caused by methicillin-resistant coagulase-negative staphylococci (CoNS). Cultures remain the gold standard but often require a few days. Thus, a rapid test could be interesting to guide antibiotic strategy earlier. The purpose of this study was to evaluate the performances of RT-PCR Xpert® MRSA/SA technique for the detection of methicillin-resistant CoNS (MRCoNS) from deep samples in patients with PJIs. RT-PCR was tested on 72 samples. Sensitivity, specificity, positive predictive value, and negative predictive value of RT-PCR method were 0.36, 0.98, 0.90, and 0.74, respectively. Although RT-PCR may allow early microbial diagnosis of PJI due to Staphylococcus aureus (MSSA and MRSA), the low sensitivity and the high cost of this method to detect MRCoNS could limit its use in this field. © 2015 Elsevier Inc.
PubMed | Microbiological Laboratory, Hopital J. Ducuing and Infectious Diseases Mobile Unit
Type: Evaluation Studies | Journal: Diagnostic microbiology and infectious disease | Year: 2015
Periprosthetic joint infections (PJIs) are frequently caused by methicillin-resistant coagulase-negative staphylococci (CoNS). Cultures remain the gold standard but often require a few days. Thus, a rapid test could be interesting to guide antibiotic strategy earlier. The purpose of this study was to evaluate the performances of RT-PCR Xpert MRSA/SA technique for the detection of methicillin-resistant CoNS (MRCoNS) from deep samples in patients with PJIs. RT-PCR was tested on 72 samples. Sensitivity, specificity, positive predictive value, and negative predictive value of RT-PCR method were 0.36, 0.98, 0.90, and 0.74, respectively. Although RT-PCR may allow early microbial diagnosis of PJI due to Staphylococcus aureus (MSSA and MRSA), the low sensitivity and the high cost of this method to detect MRCoNS could limit its use in this field.
News Article | February 21, 2017
In 1895, a physician by the name of F.A. Colby published a correspondence in the Boston Medical and Surgical Journal; his letter was titled, "Should Doctors Wear Beards?" "I wear a beard," Dr. Colby wrote, "and grant you that probably, like many of my professional brothers, it is a comfort to stroke it and look wise while making a doubtful diagnosis. It is a comfort in the cold, bleak days of winter...I cultivated mine sedulously after graduation, so that I might lose the title of 'the young doctor.'" His words still ring true in 2017. As a first-year doctor, I’ll sometimes go stretches without shaving on busy clinical rotations. I’ve noticed patients and staff treat me with more seniority when I’m bearded compared to clean-shaven. My patients no longer ask when I graduated from medical school. Supervising doctors no longer mistake me for a medical student. A bit of facial hair seems to add years of perceived expertise. For male physicians, it might then be appealing to grow a beard. We can hide our insecurities and pretend to be wiser than our years, all while crossing off another daily chore. Still, Dr. Colby's 1895 letter brings up a longstanding controversy over whether physicians should be growing beards at all—hygiene. "We note with what care the surgeon disinfects his hands, arms, instruments, all that comes in contact with the patient in a surgical case," Dr. Colby wrote,"but the beard of the doctor attending diseases and so easily communicable as some are, how many thoroughly disinfect that before visiting the next patient? Surely we should take every precaution, or not wear beards." Colby's concerns found their way into the next century, as researchers began to study the question of beard hygiene. In 1967, a study titled, "Microbiological Laboratory Hazard of Bearded Men" appeared in the journal Applied Microbiology. The authors tested "the hypothesis that a bearded man subjects his family and friends to risk of infection if his beard is contaminated by infectious microorganisms while he is working in a microbiological laboratory." After culturing bacteria and spraying volunteers' beards, the researchers sampled the beards at different time intervals and following various forms of washing. The study found “beards retained microorganisms and toxin despite washing with soap and water.” The authors also showed that infectious diseases could be transmitted from a beard to animals like chickens and guinea pigs. With respect to beards in clinical situations, the study had several shortcomings. Its sample size was small, with just four bearded volunteers and a bearded mannequin—yes, a bearded mannequin. The researchers introduced bacteria and toxins to the beards, rather than studying beards in their natural states. The focus was on microbiology laboratories and did not include broader hospital settings. Nonetheless, later studies raised similar concerns about the possible infectious risks of beards. For example, a 2000 study in the journal Anaesthesia examined the effectiveness of surgical masks for preventing bacterial contamination, finding bearded subjects shed considerably more bacteria—even when wearing masks—compared to non-bearded subjects. The authors recommended that surgical personnel “avoid wiggling the face mask” and that “bearded males may also consider removing their beards.” The presumption had long held that beards were unclean and bacteriogenic. Now, there was growing evidence to support that claim for laboratories and hospitals. But in the last few years, new studies have cast doubt on the dangers of beards in the healthcare settings. In 2014, one of the largest studies on this topic upended the prevailing wisdom. The study examined over 400 medical staff and found bacterial colonization was “similar in male healthcare workers with and without facial hair." Of note, staff without facial hair had higher rates of colonization with pathogenic bacteria like methicillin-resistant coagulase-negative staphylococci. Published in 2016, another study–titled “To Beard or Not to Beard? Bacterial Shedding Among Surgeons”—re-examined the question of beard hygiene in surgical settings. The authors compared bearded and clean-shaven subjects who performed facial motions behind surgical masks. This time, however, "bearded surgeons did not appear to have an increased likelihood of bacterial shedding compared with their nonbearded counterparts while wearing surgical masks." The cleanliness of health care providers’ facial hair might seem like a mundane question to pore over. But, in medicine, the mundane aspects of hygiene can have profound effects on patient care. Surveys suggest between 700,000 and 1.7 million healthcare-associated infections (HAIs) occur in US hospitals every year. Researchers estimate HAIs incur up to $147 billion in direct and indirect annual costs. To curb these trends, hospitals emphasize the use of hand sanitizers, disinfectant wipes, sinks, gowns, and an array of infectious disease protocols. Some hospitals have even installed motion sensors and video cameras to promote hand washing among their staff. Debates over hair hygiene are inciting controversy among leading medical organizations. For instance, the Association of periOperative Registered Nurses, an organization representing over 40,000 nurses, issued guidelines calling for stricter hair covering in operating rooms. These regulations, which led some hospitals to change surgical attire, have stirred outrage among surgeons. The American College of Surgeons released competing guidelines last year, directly challenging the nursing group's proposals. And it’s not just hair. Nearly every aspect of a doctor's attire has come under fire for cleanliness in recent years. White coats, stethoscopes, and ties have all been called out for hygiene concerns. Healthcare-associated infections remain a pressing issue, but the jury is still out on whether beards truly pose a risk to patients and colleagues in clinical care. After 122 years, we’ve yet to answer Dr. Colby’s question: "In these days of microbes, bacilli, and crawling, creeping and flying things that find a resting-place for development of diseases in the human system, coming from the air we breathe, liable to assault the weak and strong...should doctors wear beards?"
Lourtet-Hascoet J.,Microbiological Laboratory |
Bicart-See A.,J Ducuing Hospital |
Felice M.P.,Microbiological Laboratory |
Giordano G.,J Ducuing Hospital |
Bonnet E.,J Ducuing Hospital
International Journal of Infectious Diseases | Year: 2016
Objectives The aim of this study was to assess the characteristics of periprosthetic joint infection (PJI) due to Staphylococcus lugdunensis and to compare these to the characteristics of PJI due to Staphylococcus aureus and Staphylococcus epidermidis. Methods A retrospective multicentre study including all consecutive cases of S. lugdunensis PJI (2000–2014) was performed. Eighty-eight cases of staphylococcal PJI were recorded: 28 due to S. lugdunensis, 30 to S. aureus, and 30 to S. epidermidis, as identified by Vitek 2 or API Staph (bioMérieux). Results Clinical symptoms were more often reported in the S. lugdunensis group, and the median delay between surgery and infection was shorter for the S. lugdunensis group than for the S. aureus and S. epidermidis groups. Regarding antibiotic susceptibility, the S. lugdunensis strains were susceptible to antibiotics and 61% of the patients could be treated with levofloxacin + rifampicin. The outcome of the PJI was favourable for 89% of patients with S. lugdunensis, 83% with S. aureus, and 97% with S. epidermidis. Conclusion S. lugdunensis is an emerging pathogen with a pathogenicity quite similar to that of S. aureus. This coagulase-negative Staphylococcus must be identified precisely in PJI, in order to select the appropriate surgical treatment and antibiotics. © 2016 The Author(s)
PubMed | Microbiological Laboratory and J Ducuing Hospital
Type: | Journal: International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases | Year: 2016
The aim of this study was to assess the characteristics of periprosthetic joint infection (PJI) due to Staphylococcus lugdunensis and to compare these to the characteristics of PJI due to Staphylococcus aureus and Staphylococcus epidermidis.A retrospective multicentre study including all consecutive cases of S. lugdunensis PJI (2000-2014) was performed. Eighty-eight cases of staphylococcal PJI were recorded: 28 due to S. lugdunensis, 30 to S. aureus, and 30 to S. epidermidis, as identified by Vitek 2 or API Staph (bioMrieux).Clinical symptoms were more often reported in the S. lugdunensis group, and the median delay between surgery and infection was shorter for the S. lugdunensis group than for the S. aureus and S. epidermidis groups. Regarding antibiotic susceptibility, the S. lugdunensis strains were susceptible to antibiotics and 61% of the patients could be treated with levofloxacin + rifampicin. The outcome of the PJI was favourable for 89% of patients with S. lugdunensis, 83% with S. aureus, and 97% with S. epidermidis.S. lugdunensis is an emerging pathogen with a pathogenicity quite similar to that of S. aureus. This coagulase-negative Staphylococcus must be identified precisely in PJI, in order to select the appropriate surgical treatment and antibiotics .
Kootallur B.N.,Microbiological Laboratory |
Thangavelu C.P.,Microbiological Laboratory |
Mani M.,Microbiological Laboratory
Indian Journal of Medical Microbiology | Year: 2011
The major impetus for bacterial identification came after the advent of solid culture media. Morphological appearance of bacterial colonies was often sufficient for their identification in the laboratory. Even in modern times, preliminary identification of most cultivable bacteria is based on such morphological characters. Advances have been made media for the presumptive identifi cation of common organisms encountered in clinical samples. Phenotypic characterisation of bacteria with, physiological tests with a battery of biochemical tests differentiate related bacterial genera as well as confirm their identity.. Each laboratory can select its own method(s) of identification, provided they are based on scientific / epidemiological evidence; clinical laboratory and standards institute (CLSI) is a widely accepted organization and laboratories in many parts of the world follow its recommendations for bacterial identification. Some of the latest advances in identification include Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectroscopy (MALDI-TOF) is a state of art facility used for fast and reliable species-specific identification of bacteria including Mycobacteria and fungi including yeasts. However the single most important factor that decides the method of bacterial identification in any laboratory is the cost involved. In the final analysis, selection of tests for bacterial identification should be based on their standardization with proper scientific basis. Considering the cost and lack of easy availability of commercial kits, we have put forward a simplified and rapid method of identification for most commonly encountered bacterial pathogens causing human infection in India.