Multi-omics analysis identifies potential microbial and metabolite diagnostic biomarkers of bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) is a common clinical manifestation of a perturbed vaginal ecology associated with adverse sexual and reproductive health outcomes if left untreated. The existing diagnostic modalities are either cumbersome or require skilled expertise, warranting alternate tests. Application of machine-learning tools to heterogeneous and high-dimensional multi-omics datasets finds promising potential in data integration and may aid biomarker discovery.

OBJECTIVES

The present study aimed to evaluate the potential of the microbiome and metabolome-derived biomarkers in BV diagnosis. Interpretable machine-learning algorithms were used to evaluate the utility of an integrated-omics-derived classification model.

METHODS

Vaginal samples obtained from reproductive-age group women with (n = 40) and without BV (n = 40) were subjected to 16S rRNA amplicon sequencing and LC-MS-based metabolomics. The vaginal microbiome and metabolome were characterized, and machine-learning analysis was performed to build a classification model using biomarkers with the highest diagnostic accuracy.

RESULTS

Microbiome-based diagnostic model exhibited a ROC-AUC (10-fold CV) of 0.84 ± 0.21 and accuracy of 0.79 ± 0.18, and important features were Aerococcus spp., Mycoplasma hominis, Sneathia spp., Lactobacillus spp., Prevotella spp., Gardnerella spp. and Fannyhessea vaginae. The metabolome-derived model displayed superior performance with a ROC-AUC of 0.97 ± 0.07 and an accuracy of 0.92 ± 0.08. Beta-leucine, methylimidazole acetaldehyde, dimethylethanolamine, L-arginine and beta cortol were among key predictive metabolites for BV. A predictive model combining both microbial and metabolite features exhibited a high ROC-AUC of 0.97 ± 0.07 and accuracy of 0.94 ± 0.08 with diagnostic performance only slightly superior to the metabolite-based model.

CONCLUSION

Application of machine-learning tools to multi-omics datasets aid biomarker discovery with high predictive performance. Metabolome-derived classification models were observed to have superior diagnostic performance in predicting BV than microbiome-based biomarkers.

Epidemiology, clinical profile, management, and outcome of COVID-19-associated rhino-orbital-cerebral mucormycosis in 2826 patients in India - Collaborative OPAI-IJO Study on Mucormycosis in COVID-19 (COSMIC), Report 1

Purpose

COVID-19-associated rhino-orbital-cerebral mucormycosis (ROCM) has reached epidemic proportion during India's second wave of COVID-19 pandemic, with several risk factors being implicated in its pathogenesis. This study aimed to determine the patient demographics, risk factors including comorbidities, and medications used to treat COVID-19, presenting symptoms and signs, and the outcome of management.

Methods

This was a retrospective, observational study of patients with COVID-19-associated ROCM managed or co-managed by ophthalmologists in India from January 1, 2020 to May 26, 2021.

Results

Of the 2826 patients, the states of Gujarat (22%) and Maharashtra (21%) reported the highest number of ROCM. The mean age of patients was 51.9 years with a male preponderance (71%). While 57% of the patients needed oxygen support for COVID-19 infection, 87% of the patients were treated with corticosteroids, (21% for > 10 days). Diabetes mellitus (DM) was present in 78% of all patients. Most of the cases showed onset of symptoms of ROCM between day 10 and day 15 from the diagnosis of COVID-19, 56% developed within 14 days after COVID-19 diagnosis, while 44% had delayed onset beyond 14 days. Orbit was involved in 72% of patients, with stage 3c forming the bulk (27%). Overall treatment included intravenous amphotericin B in 73%, functional endoscopic sinus surgery (FESS)/paranasal sinus (PNS) debridement in 56%, orbital exenteration in 15%, and both FESS/PNS debridement and orbital exenteration in 17%. Intraorbital injection of amphotericin B was administered in 22%. At final follow-up, mortality was 14%. Disease stage >3b had poorer prognosis. Paranasal sinus debridement and orbital exenteration reduced the mortality rate from 52% to 39% in patients with stage 4 disease with intracranial extension (p < 0.05).

Conclusion

: Corticosteroids and DM are the most important predisposing factors in the development of COVID-19-associated ROCM. COVID-19 patients must be followed up beyond recovery. Awareness of red flag symptoms and signs, high index of clinical suspicion, prompt diagnosis, and early initiation of treatment with amphotericin B, aggressive surgical debridement of the PNS, and orbital exenteration, where indicated, are essential for successful outcome.

Sensitivity and specificity of automated analysis of single-field non-mydriatic fundus photographs by Bosch DR Algorithm-Comparison with mydriatic fundus photography (ETDRS) for screening in undiagnosed diabetic retinopathy

Diabetic retinopathy (DR) is a leading cause of blindness among working-age adults. Early diagnosis through effective screening programs is likely to improve vision outcomes. The ETDRS seven-standard-field 35-mm stereoscopic color retinal imaging (ETDRS) of the dilated eye is elaborate and requires mydriasis, and is unsuitable for screening. We evaluated an image analysis application for the automated diagnosis of DR from non-mydriatic single-field images. Patients suffering from diabetes for at least 5 years were included if they were 18 years or older. Patients already diagnosed with DR were excluded. Physiologic mydriasis was achieved by placing the subjects in a dark room. Images were captured using a Bosch Mobile Eye Care fundus camera. The images were analyzed by the Retinal Imaging Bosch DR Algorithm for the diagnosis of DR. All subjects also subsequently underwent pharmacological mydriasis and ETDRS imaging. Non-mydriatic and mydriatic images were read by ophthalmologists. The ETDRS readings were used as the gold standard for calculating the sensitivity and specificity for the software. 564 consecutive subjects (1128 eyes) were recruited from six centers in India. Each subject was evaluated at a single outpatient visit. Forty-four of 1128 images (3.9%) could not be read by the algorithm, and were categorized as inconclusive. In four subjects, neither eye provided an acceptable image: these four subjects were excluded from the analysis. This left 560 subjects for analysis (1084 eyes). The algorithm correctly diagnosed 531 of 560 cases. The sensitivity, specificity, and positive and negative predictive values were 91%, 97%, 94%, and 95% respectively. The Bosch DR Algorithm shows favorable sensitivity and specificity in diagnosing DR from non-mydriatic images, and can greatly simplify screening for DR. This also has major implications for telemedicine in the use of screening for retinopathy in patients with diabetes mellitus.

Posterior Chamber Scleral Fixation of Intraocular Lenses in Post-Vitrectomised Aphakic Eyes

INTRODUCTION

The best method of aphakia correction is in the bag implantation of Posterior Chamber Intraocular Lens (PCIOL). When this ideal procedure is not possible due to lack of integrity of posterior capsule or zonules, the other alternatives are broadly categorized into two: extraocular and intraocular. Whereas, the former includes contact lenses and aphakic glasses, the latter ones are further divided into anterior and posterior chamber methods. Anterior Chamber Intraocular Lenses (ACIOL) can be with or without iris claw. At the posterior chamber, fixation of the lenses can be with glue or sutures. When there is combined Pars Plana Vitrectomy (PPV) and lensectomy or if the indication of PPV is dropped nucleus or intraocular lens, a modality of aphakia correction should be devised. Posterior Chamber Scleral Fixation of Intraocular Lenses (PCSFIOL) with sutures is a preferred method because of its low complication profile. However, data on correction of aphakia after combined PPV and lensectomy is limited. To fill in this gap in knowledge, we evaluated the secondary PCSFIOL in aphakic eyes after previous PPV and lensectomy.

AIM

To assess the outcome and complication profile of a large series of patients who underwent secondary PCSFIOL implantation with sutures after combined PPV and lensectomy.

MATERIALS AND METHODS

Records of all patients who had undergone secondary PCSFIOL implantation with sutures after combined PPV and lensectomy from 2010 to 2014 were reviewed retrospectively for visual outcomes and complications. Patients' demographic data, indication for PPV, best corrected preoperative and postoperative visual acuities, complications of surgery, and indications of PCSFIOL and length of follow up were collected and analyzed.

RESULTS

A total of 148 eyes of 148 patients (127 males and 21 females) were identified. Mean age at surgery was 32.5±8 years (range 2.5-73 years) with a mean follow up 23±14 months (range 3-114 months). A total of 95.27%, 2.70% and 2.02% of patients had improvement, maintenance and worsening of their final postoperative visual acuities respectively. A total of 32 (21.62%) of 148 eyes had postoperative complications from PCSFIOL with Epiretinal Membrane (ERM) formation being the most common. They all required one form of management or the other. Suture breakage leading to PCSFIOL subluxation or dislocation occurred in four eyes (2.70%).

CONCLUSION

PCSFIOL with sutures is a preferred method in the management of post-vitrectomised aphakic eyes when the capsular or zonular support is not adequate for in the bag implantation of posterior chamber intraocular lenses.

The changing face of community-acquired methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infection, both in hospitalised patients with significant healthcare exposure and in patients without healthcare risk factors. Community-acquired methicillin-resistant S. aureus (CA-MRSA) are known for their rapid community transmission and propensity to cause aggressive skin and soft tissue infections and community-acquired pneumonia. The distinction between the healthcare-associated (HA)-MRSA and CA-MRSA is gradually fading owing to the acquisition of multiple virulence factors and genetic elements. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community or HA status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacotherapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-β-lactam antibacterial agents. This review aimed at illuminating the characteristic features of CA-MRSA, virulence factors, changing clinical settings and molecular epidemiology, insurgence into the hospital settings and therapy with drug resistance.

Coagulase-negative staphylococci causing blood stream infection at an Indian tertiary care hospital: Prevalence, antimicrobial resistance and molecular characterisation

INTRODUCTION

Recent years have seen a rise of coagulase-negative staphylococci (CoNS) from common contaminants to agents of nosocomial blood stream infections (BSI's). Molecular typing and establishing a correlation with antibiotic resistance is essential particularly in countries like India where genotyping studies for drug-resistant CoNS are sparse.

METHODS

A prospective study was done over 18 months, wherein 42,693 blood samples were received, and 59 patients with BSI due to CoNS were evaluated. The isolates recovered were identified by a biochemical test panel and matrix-assisted laser desorption ionization - time of flight mass spectrometry followed by antimicrobial susceptibility testing by Kirby-Baur disc diffusion method and E-test strips. Staphylococcal chromosomal cassette mec (SCCmec) element was characterised by multiplex polymerase chain reaction for all methicillin-resistant (MR) isolates.

RESULTS

The majority of CoNS isolated were constituted by Staphylococcus haemolyticus (47.5%) followed by Staphylococcus epidermidis (33.9%), Staphylococcus hominis (11.86%), Staphylococcus cohnii (5.08%) and Staphylococcus warneri (1.69%). Among all isolates 57.6% were MR with statistically significant higher resistance versus methicillin sensitive-CoNS. This difference was significant for erythromycin (76% vs. 44%, P = 0.011), rifampicin (50% vs. 12%,P= 0.002) and amikacin (26.5% vs. 4%, P = 0.023), ciprofloxacin (64.7% vs. 20%, P = 0.001) and cotrimoxazole (55.9% vs. 20%, P = 0.006). SCCmec type I was predominant (61.8%, P = 0.028) and exhibited multidrug resistance (76.2%). Coexistence of SCCmec type I and III was seen in 8.82% MR isolates.

CONCLUSION

CoNS exhibit high antimicrobial resistance thereby limiting treatment options. The presence of new variants of SCCmec type in hospital-acquired CoNS may predict the antibiotic resistance pattern. This is the first evaluation of the molecular epidemiology of CoNS causing BSI from India and can serve as a guide in the formulation of hospital infection control and treatment guidelines.

Application of real-time quantitative polymerase chain reaction assay to detect Legionella pneumophila in patients of community-acquired pneumonia in a tertiary care hospital

Legionella pneumophila is one of the important pathogen responsible for community -acquired pneumonia attributing for 1-5% of cases. Since early and accurate therapy reduces mortality, rapid and reliable diagnostic methods are needed. A total of 134 samples of blood, urine and respiratory tract fluids were collected. Blood was tested for IgG, IgM and IgA antibodies using commercially available kits. A total of 8 (6%) samples were found to be positive for L. pneumophila by quantitative reverse transcription polymerase chain reaction (qRT-PCR), compared to conventional PCR where 6 (4.4%) samples were positive. Serology was positive in a total of 32 (23%) cases though only 3 (2.2%) of the PCR-positive cases were positive by serology as well. These results suggest that real-time PCR can detect Legionella infection early in the course of the disease before serological response develops.

Ureaplasma: current perspectives

Ureaplasma species are the most prevalent genital Mycoplasma isolated from the urogenital tract of both men and women. Ureaplasma has 14 known serotypes and is divided into two biovars- Ureaplasma parvum and Ureaplasma urealyticum. The organism has several genes coding for surface proteins, the most important being the gene encoding the Multiple Banded Antigen (MBA). The C-terminal domain of MBA is antigenic and elicits a host antibody response. Other virulence factors include phospholipases A and C, IgA protease and urease. Besides genital tract infections and infertility, Ureaplasma is also associated with adverse pregnancy outcomes and diseases in the newborn (chronic lung disease and retinopathy of prematurity). Infection produces cytokines in the amniotic fluid which initiates preterm labour. They have also been reported from renal stone and suppurative arthritis. Genital infections have also been reported with an increasing frequency in HIV-infected patients. Ureaplasma may be a candidate 'co factor' in the pathogenesis of AIDS. Culture and polymerase chain reaction (PCR) are the mainstay of diagnosis. Commercial assays are available with improved turnaround time. Micro broth dilution is routinely used to test antimicrobial susceptibility of isolates. The organisms are tested against azithromycin, josamycin, ofloxacin and doxycycline. Resistance to macrolides, tetracyclines and fluoroquinolones have been reported. The susceptibility pattern also varies among the biovars with biovar 2 maintaining higher sensitivity rates. Prompt diagnosis and initiation of appropriate antibiotic therapy is essential to prevent long term complications of Ureaplasma infections. After surveying PubMed literature using the terms 'Ureaplasma', 'Ureaplasma urealyticum' and 'Ureaplasma parvum', relevant literature were selected to provide a concise review on the recent developments.

Endocapsular hematoma: a rare form of ocular hemorrhage after thrombolysis with streptokinase

Context:

Endocapsular hematoma has previously been described as a cataract surgery complication more commonly observed in eyes receiving a combined cataract and glaucoma surgery. However, it can also be a rare form of ocular bleed following thrombolysis with streptokinase.

Case Report:

A 65-year-old diabetic male presented to us with complain of sudden painless diminution of vision in his left eye, which he developed while he was being thrombolysed with streptokinase administered intravenously for an episode of acute myocardial infarct. On examination, left eye was pseudophakic with collection of blood in the capsular bag (Endocapsular hematoma).

Conclusion:

Endocapsular hematoma can be a rare form of ocular bleeding complicated by thrombolysis. Reporting this case becomes more relevant in the present era with increasing number of patients suffering from ischemic heart disease and likely to undergo thrombolysis.

Burden of healthcare-associated infections in a paediatric intensive care unit of a developing country: a single centre experience using active surveillance

Healthcare-associated infections (HAIs) are an important cause of morbidity and mortality among critically ill patients of all age groups. This prospective surveillance study was performed to estimate the burden of HAIs in a paediatric intensive care unit (PICU) of a developing country. During the 12-month study, 187 patients were treated in the PICU for ≥48h, of whom 36 patients had 44 episodes of HAIs. The crude infection rate and incidence density (ID) of HAI were 19.3/100 patients and 21/1,000 patient-days, respectively. Of the 44 episodes of HAI, 27 (61%) were healthcare-associated pneumonia (HAP), 12 (27%) were bloodstream infections (HA-BSI) and four (9%) were urinary tract infections. Mean length of stay and mortality were significantly higher in patients who developed an HAI [25 vs 7 days (P<0.0001) and 50% vs 27.8% (P<0.005), respectively]. Acinetobacter spp. were the commonest infecting bacteria in both HAP and HA-BSI. For developing countries, active surveillance is essential to reduce the burden of HAIs in high risk groups.

Incidence and characterization of Clostridium perfringens isolated from antibiotic-associated diarrhoeal patients: a prospective study in an Indian hospital

Clostridium perfringens has been reported as causing between 2-15% of all cases of antibiotic-associated diarrhoea (AAD), and may be diagnosed by detection of enterotoxin in faeces. A prospective study comprising 150 diarrhoeal patients and 100 non-diarrhoeal controls was undertaken to assess the incidence of C. perfringens-associated diarrhoea in an Indian hospital. Methods used included C. perfringens culture, reverse passive latex agglutination (RPLA) and enzyme-linked immunosorbent assay (ELISA) for detection of enterotoxin, and polymerase chain reaction (PCR) assay for the presence of enterotoxin gene. Attempts were made to type the isolates by multiplex PCR. Of the 150 diarrhoeal stool samples tested, 13 were culture positive. Of these, four were positive for C. perfringens enterotoxin by RPLA, two were positive by PCR and two were positive by RPLA and ELISA. Twenty-seven samples were positive for culture of C. perfringens in non-diarrhoeal controls but none were positive for enterotoxin either by RPLA or by PCR. The average incidence of C. perfringens AAD using these methods was 2.6%. Toxin typing showed that all the isolates belonged to type A. To conclude, the relatively low incidence of toxigenic C. perfringens suggests that enterotoxigenic C. perfringens is not a major cause of AAD in this population.

Bacteriological and antimicrobial susceptibility profile of soft tissue infections from Northern India

BACKGROUND

Soft tissue infections require a judicious combination of antimicrobial therapy in addition to surgical debridement to limit tissue loss and preserve life.

AIMS

To study the bacterial etiology of soft tissue infections and their antimicrobial susceptibility pattern.

SETTINGS AND DESIGN

A single institutional retrospective study of one year duration from January to December 2002.

MATERIALS AND METHODS

A total of 5039 consecutive pus samples received in the Bacteriology Laboratory was analyzed from the records.

RESULTS

There were a total of 2783 bacterial isolates comprising of 1504 gram negative bacilli and 1279 gram positive cocci. Staphylococcus aureus was the commonest isolate followed by Escherichia coli and Pseudomonas species. Methicillin resistance in S. aureus was found to be 38.56%, high level aminoglycoside resistance was observed in 53.3% enterococci and 66.75% of the gram negative bacilli were extended spectrum beta-lactamase producers. Rifampicin and vancomycin showed best activity for S. aureus; for gram-negative bacilli, piperacillin-tazobactam combination showed best activity.

CONCLUSIONS

Continuous monitoring of antimicrobial susceptibility pattern in individual settings together with their judicious use is emphasized to minimize emergence of drug resistant bacteria.

A study of bacteremia in febrile neutropenic patients at a tertiary-care hospital with special reference to anaerobes

Patients with hematological malignancies who are receiving chemotherapy suffer prolonged periods of neutropenia, which leads to a greater risk of infection and mortality. A prospective study was conduced to determine the incidence of bacteremia in patients of hematological malignancies over a 2-yr period. A total of 119 episodes of febrile neutropenia occurred among 96 consecutive patients, of which 35 episodes were associated with bacteremia. Forty-four percent of the isolated bacteria were Gram-positive aerobes and 46% were Gram-negative aerobes. Staphylococcus aureus, Enterococcus spp., and Escherichia coli were the most common isolates. Gram-negative bacteremia was associated with a higher mortality. Anaerobes accounted for 4.4% of all isolates. The episodes of anaerobic bacteremia were polymicrobial and had a fatal outcome. A high incidence of antimicrobial resistance among aerobic and anaerobic bacteria was also recorded. Compared to previous years, a shift from a predominating Gram-negative to a Gram-positive etiology was noted. The initial empiric antibiotic regimens should be based on a local knowledge of the most common causative microorganisms, their sensitivity pattern, and the outcome of bacteremia.

Antimicrobial resistance profile of nosocomial uropathogens in a tertiary care hospital

A retrospective analysis was done of the resistance pattern of urinary tract pathogens isolated over a 4 months period in a tertiary care hospital. There were a total of 871 clinical isolates comprising of 793 gram negative bacilli and 78 gram positive cocci obtained from 5477 consecutive urine samples. Extended spectrum beta lactamase production was observed in 71.5% of the gram negative bacilli; of these 6.18% were also inhibitor resistant. High level aminoglycoside resistance was observed in 70.17% of Enterococcus isolates while methicillin resistance was documented in 23.8% of the Staphylococcus isolates. A high level of resistance was also noted for ciprofloxacin. Multidrug resistance is a common problem in hospitals which emphasizes the need for judicious use of antimicrobial agents and their continuous in vitro monitoring.

Group B streptococcal bacteremia in an adult: a case report from India

The incidence of group B streptococcal bacteremia in adults has increased in recent years, particularly in patients with severe underlying diseases. However, group B still remains an unusual pathogen in adults in developing countries. We report a case of group B streptococcal bacteremia in a non-pregnant adult, the only case reported in our hospital. The organism was only isolated from the blood and responded to specific therapy.

Infections caused by Gemella spp.: case reports from India

Human infections caused by Gemella spp. are rare. We report here our experience of the isolation of species of Gemellae from various clinical samples. Careful and complete identification of this organism will prevent diagnostic and therapeutic delays and bring more such cases to light.

Bioterrorism: a threat for which we are ill prepared

Of the weapons of mass destruction, the biological ones are the most feared and bioterrorism has become one of the most vicious threats to civilized society in recent times. Biological weapons have been sporadically used for centuries. Despite international regulations, there has been a global re-emergence of the threat of biological warfare. As many as 17 countries are suspected of either including or developing biological agents in their weapons programmes. In the past decade, a number of terrorist organizations with access to bioweapons technology have emerged. Current surveillance systems may be inadequate to detect biological attacks. The onset of illness is often delayed, thus the timing and location of such an event may be extremely difficult to identify. We are unfamiliar with most of the agents of biological warfare and are ill-equipped to handle the consequences of such an attack. In addition, there is no apparent coherent policy to handle a biological terrorist incident. Given the enormity of what is possible in the event of a biological attack, we must be prepared to detect, diagnose, epidemiologically characterize and respond appropriately to biological weapons. Of the potential biological weapons, smallpox and anthrax pose the greatest threats.

Botulism: An update

Botulism is a paralytic illness caused by the action of a neurotoxin elaborated by Clostridium botulinum. Other clostridial bacteria, like C.butyricum and C.baratii can also produce the toxin leading to signs and symptoms of botulism. Though rare, the illness is potentially fatal and can masquerade as other illnesses making diagnosis difficult. Physicians need to familiarize themselves with the disease as prompt recognition and early treatment can considerably curtail the fatal outcome in the affected and prevent additional cases in the unaffected. New diagnostic, therapeutic and preventive modalities to tackle the disease have come into focus. Botulinum toxin, generally considered a potent poison, is successfully being used for treatment of various neuromuscular disorders representing one of the most dramatic role reversals of modern times.

Infective complications of central venous catheters in cardiac surgical patients

Prospective randomised study was conducted over a 24 months period in a cardiac surgical intensive care unit to determine the incidence of infection associated with multilumen venous catheters. The influence of various factors including fever, peripheral blood culture, catheter site, catheter usage for monitoring central venous pressure and/inotrope therapy on infection rates were statistically evaluated. A total of 100 catheters submitted to the Microbiology laboratory were bacteriologically examined. Forty-nine of these were inserted into upper body sites, and 51 were inserted into the femoral vein. Twenty-one were triple-lumen catheters. Catheters were removed when a central line was no longer necessary. Catheter tips were cultured by semiquantitative technique for aerobic and anaerobic bacteria. Bacteremia occurred in 3% of catheter insertions; (Enterococcus faecalis, one; Enterobacter spp. One; Acinetobacter spp., one); and catheter colonisation developed in 24%. Neither catheter colonisation nor catheter related infection were associated with any of the risk factors evaluated. Our data indicates that central venous catheters are safe to use in our patients. The inability to identify "risk factors" for catheter infection emphasise the need to maintain a high index of suspicion.

The incidence of Legionella pneumophila: a prospective study in a tertiary care hospital in India

The prevalence of Legionella pneumophila causing community-acquired pneumonia (CAP) in patients who were admitted to hospital was investigated. Between April 1997 and December 1998, 60 patients admitted to the All India Institute of Medical Sciences with CAP, were included in the study. Aetiological diagnosis was based on the results of routine microbiological blood culture for bacteria and serological test by enzyme linked immunosorbent assay (ELISA) for L. pneumophila serogroup 1-7. Eight (13%) patients had a conventional bacterial aetiology and nine (15%) had serological evidence of recent infection with L. pneumophila. Legionella pneumophila may be an important cause of CAP in adults in developing countries. Empiric antimicrobial treatment should include a combination of agents to cover both atypical agents and bacterial pathogens.

Drug-resistant Salmonella enterica serotype paratyphi A in India

The incidence of enteric fever caused by Salmonella enterica serotype Paratyphi A has been increasing in India since 1996. In 1998, the incidence of enteric fever caused by drug- resistant S. Paratyphi A abruptly increased in the New Delhi region. In the first 6 months of 1999, 32% of isolates were resistant to both chloramphenicol and cotrimoxazole and another 13% were resistant to more than two antibiotics.

Incidence of Clostridium difficile infection: a prospective study in an Indian hospital

Clostridium difficile is the commonest cause of hospital-acquired diarrhoea. A prospective study comprising of 156 patients and 54 healthy controls was undertaken to assess C. difficile associated diarrhoea (CDAD) incidence in an Indian hospital. Methods used included C. difficile culture and enzyme linked immunosorbent assay (ELISA) for Toxin A. Attempts were made to type isolates by antibiogram and SDS-PAGE. Of the 210 stool samples tested, 12 gave positive results in at least one assay. Of these, 11 were positive by the ELISA method, eight by culture, and seven by both methods. Neither the organisms nor the toxin was found in healthy controls or neonates. The average disease incidence of CDAD estimated by using both methods was 15%. Two antibiotypes of the isolates were obtained and of the isolates characterized by SDS-PAGE, two had identical patterns. This study shows that CDAD is an emerging problem in Indian hospitals. Monitoring should enable the development and implementation of policies and procedures that minimize the risk of this nosocomial pathogen.

Clinical spectrum of bacteroidaceae in a tertiary care hospital

Members of Bacteroidaceae family are the most commonly isolated anaerobic pathogens in humans. This study summarises our experience of isolation and antimicrobial susceptibility pattern of these anaerobes from diverse clinical infections in a tertiary care hospital. Over a period of 5 years, 611 samples were received for anaerobic culture. Of these, 53 specimens yielded 62 anaerobic isolates. Thirty of the 62 isolates (48.4%) belonged to Bacteroidacea family obtained from 29 patients. They comprised of 14 (14/32; 43.7%) Prevotella spp., 13 (13/32; 40.6%) Bacteroides spp., 3 (3/32; 9.3%) Porphyromonas spp and Fusobacterium (2/32; 6.2%). In 14 of 27 patients (48%) the infection was polymicrobial. All the isolated strains were sensitive to metronidazole. This study highlights need for adopting anaerobic culture technique as a routine diagnostic procedure and constant monitoring of antimicrobial susceptibility of all anaerobic isolates.

Prevalence of Mycoplasma pneumoniae and Chlamydia pneumoniae in children with community acquired pneumonia

A prospective one year study was performed on 62 children admitted at the All India Institute of Medical Sciences with community acquired pneumonia (CAP) for the prevalence of Mycoplasma pneumoniae and Chlamydia pneumoniae. Diagnosis of infection with M. pneumoniae was based on serological tests viz microparticle agglutination test for detection of IgM antibodies and indirect immunofluorescence test for antigen detection from throat swabs (sensitivity 85.7%, specificity 93.3%). The indirect solid-phase enzyme immunoassay for detection of IgG antibodies was used to determine the prevalence of C. pneumoniae (sensitivity 88.8%, specificity 75.8%). Seventeen patients (27.4%) were found to have serological evidence of M. pneumoniae infection whereas only 4 (6.4%) patients were seropositive for C. pneumoniae. Results of this study indicate that M. Pneumoniae plays a significant role in CAP in infants and young children. Thus specialized laboratory testing for these agents should be more widely used thereby affecting empiric antibiotic regimens.

Anaerobic septicaemia by Fusobacterium necrophorum: Lemierre's syndrome

Lemierre's syndrome is characterized by acute pharyngotonsillitis with secondary thrombophlebitis of the internal jugular vein which is complicated by multiple metastatic foci of infections. This syndrome is caused by Fusobacterium necrophorum in healthy young persons and is extremely rare in occurrence. A pre-school child with Lemierre's syndrome is reported. The diagnostic and therapeutic aspects are emphasized in order to sensitize physicians to this uncommon condition.

The microbial spectrum of brain abscess with special reference to anaerobic bacteria

The bacteriological and clinical findings of 18 cases of brain abscess are presented. Identification and antimicrobial susceptibility of anaerobic strains was performed both by conventional methods and the newer RapID ANA II panel and E-test methods, respectively. Characterization of the anaerobic isolates was done by restriction fragment length polymorphism (RFLP). Anaerobic or aerobic organisms alone were recovered in three (16.6%), and mixed aerobic and anaerobic in another three (16.6%) patients. There were nine anaerobic isolates. The predominant anaerobes were Prevotella melaninogenicus (four isolates), Bacteroides preacutus (three isolates), Fusobacterium nucleatum and Peptostreptococcus sp. (one isolate each). A total of six aerobic isolates, all of which were Gram-positive cocci were recovered. All the anaerobic isolates were susceptible to metronidazole, but two isolates of P. melaninogenicus were resistant to penicillin. There was complete agreement between the identification based on biochemical profiles and RFLP patterns. These findings indicate the microbial complexity of brain abscess and the need to target antimicrobial therapy against both the aerobic and anaerobic components of infection.