Evaluation of different linezolid susceptibility testing methods and detection of linezolid resistance gene (cfr) in staphylococcal isolates

Linezolid is an effective oxazolidinone antibiotic against multi resistant Gram-positive organisms. Linezolid resistance is an emerging problem and some controversy exists about the reliability of different phenotypic methods of linezolid susceptibility testing. Fifty isolates each of methicillin resistant S. aureus (MRSA) and Staphylococcus haemolyticus were tested for linezolid susceptibility using Kirby-Bauer disc diffusion, E-test, automated system VITEK2, Broth micro-dilution (reference method) and PCR for the cfr gene. Six resistant isolates were identified, three each in MRSA and S. haemolyticus, all carrying the cfr gene. E-test and VITEK2 were found to be more accurate than disc diffusion test.

Influence of COVID-19 over seasonal influenza activity in southern India

Basic epidemiological data is urgently needed in order to ascertain the changes brought about by COVID-19 pandemic, and help researchers, clinicians, and policy makers in addressing these issues. Data on influenza positivity from 2009 to 2019 was collected from Regional Influenza laboratory, JIPMER. Being COVID testing centre we tested samples (2020-2023) from Tamilnadu and Pondicherry. All SARI samples which were negative for COVID-19 were subjected to Influenza testing as regular surveillance activity was suspended. On comparison we found significant reduction in detection rates of influenza A H1N1, H3N2 and influenza B (p value = <0.01).

Genome sequences of bla NDM-1 producing Acinetobacter lactucae isolated from immunocompromised patients in India

Among the species within Acb-complex, Acinetobacter lactucae has not been frequently isolated from clinical settings, unlike Acinetobacter baumannii, which is an important nosocomial pathogen. We report the genomic sequences of A. lactucae strains (PKAL1732 and 1828C) harboring multiple-resistance determinants including metallo-β-lactamase (bla NDM-1) isolated from immunocompromised patients admitted to a referral hospital in India.

Structure Elucidation and Interaction Dynamics of MefA-MsrD Efflux Proteins in Streptococcus pneumoniae: Impact on Macrolide Susceptibility

Macrolides are empirically used to treat bacterial community-acquired pneumonia (CAP). Streptococcus pneumoniae, being the major pathogen responsible for bacterial CAP with high mortality rates, express MefA-MsrD efflux pumps to hinder macrolide susceptibility. Despite its importance, the structural features of the efflux-protein complex and its impact on macrolide susceptibility have not yet been elucidated explicitly. Therefore, in the present study, combining homology, threading, and dynamics approaches, MefA and MsrD proteins in pathogenic S. pneumoniae were modeled. Both membrane (lipid-bilayer) and cytoplasmic (aqueous) environments were considered to simulate the MefA and MsrD proteins in their ideal cellular conditions followed by dynamics analyses. The simulated MefA structure represented a typical major facilitator superfamily protein structure with 13 transmembrane helices. MefA-MsrD interaction via clustering-based docking revealed low-energy conformers with stable intermolecular interactions. The higher clinical MIC value of azithromycin over erythromycin was reflected upon erythromycin eliciting stronger interactions (dissociation constant or ki = ∼52 μM) with the cytoplasmic ATP-binding MsrD than azithromycin (ki = ∼112 μM). The strong (binding energy = -132.1 ± 9.5 kcal/mol) and highly stable (root-mean-square fluctuation < 1.0 Å) physical association between MefA with MsrD was validated and was found to be unaffected by the antibiotic binding. Higher propensity of the macrolides to interact with MsrD than MefA established the importance of the former in macrolide susceptibility. Ours is probably the first report on the structural arrangements in the MefA-MsrD efflux complex and the macrolide susceptibility in S. pneumoniae. This study provides a novel lead for experimental explorations and efflux-pump inhibitor designs.

A rare and fatal case of tubo-ovarian abscess due to Burkholderia pseudomallei presenting as puerperal sepsis

Introduction

Melioidosis is an emerging life-threatening infectious disease caused by the Gram-negative Burkholderia pseudomallei found in contaminated soil and surface ground water. It often presents with varied clinical manifestations and has a high mortality if left untreated due to lack of clinical suspicion. Here we report a rare and fatal case of tubo-ovarian abscess presenting as puerperal sepsis due to B. pseudomallei in a young woman.

Case report

A 25-year-old female presented for medical consultation at day 43 postpartum complaining of fever on and off for the past 40 days associated with vomiting. On per speculum examination, greenish discharge from the cervix was seen and a right adnexal mass was felt which was cystic in consistency, non-tender and pushing the cervix to the left side. An exploratory laparotomy was carried out and pus was drained from below the rectus sheath, and from the right tubo-ovarian mass. Peripheral blood and the pus samples collected intraoperatively grew B. pseudomallei . The patient died on the fifth post-operative day due to septic shock with disseminated intravascular coagulation secondary to puerperal sepsis.

Conclusion

Melioidosis is a fatal but treatable disease when it is promptly diagnosed. In countries such as India, where tuberculosis is highly endemic, underdiagnosis of melioidosis can be common. Clinicians and microbiologists should have a high index of suspicion of melioidosis especially in individuals with underlying illness.

Multiple mechanisms of linezolid resistance in Staphylococcus haemolyticus detected by whole-genome sequencing

Introduction. Linezolid is an effective therapeutic option for treating severe infections caused by multidrug-resistant Gram-positive organisms. Several mechanisms have been reported to be responsible for resistance to this antibiotic.Hypothesis or Gap Statement. Although several mechanisms of linezolid resistance have been reported in Staphylococcus haemolyticus, the prevalence and potential for horizontal transfer of resistance genes have not been fully characterized, particularly among S. haemolyticus isolates from India.Aim. To perform whole-genome sequencing (WGS) of linezolid-resistant S. haemolyticus isolates to characterize the resistance mechanisms.Methodology. WGS was performed for 16 linezolid-resistant S. haemolyticus isolates to check for the presence of cfr, optrA and poxtA genes and mutations in 23S rRNA and ribosomal proteins (L3, L4 and L22) that are possible mechanisms implicated in linezolid resistance. Sequence types were identified using MLST finder. The minimum inhibitory concentration (MIC) of linezolid was determined using the E-test method. Polymerase chain reaction (PCR) was carried out for the detection of the cfr gene.Results. The study documented three different mechanisms of linezolid resistance in S. haemolyticus. Thirteen of the 16 isolates were phenotypically resistant to linezolid, of which 12 were positive for the cfr gene. The G2603T mutation in 23S rRNA was found in the majority of the isolates (n=13). Ten isolates had the R138V mutation in L3 ribosomal protein. Twelve isolates with the cfr gene in combination with either G2603T or R138V mutations displayed extremely high MIC values. Surprisingly, three phenotypically sensitive isolates were found to be positive for the cfr gene but negative for other resistance mechanisms. Importantly, in almost half of the isolates the cfr gene was present on a plasmid. ST3 and ST1 were found to be the predominant sequence types.Conclusion. All phenotypically resistant isolates exhibited two or three linezolid resistance mechanisms. The cfr gene was found on plasmids in many isolates, demonstrating its potential for horizontal transfer to more pathogenic organisms.

Early- vs Late-onset Ventilator-associated Pneumonia in Critically Ill Adults: Comparison of Risk Factors, Outcome, and Microbial Profile

Background

Ventilator-associated pneumonia (VAP) is one of the most frequent hospital-acquired infections, which develops in mechanically ventilated patients after 48 hours of mechanical ventilation. The purpose of this study was to determine the incidence rate, various risk factors, microbiological profile, and outcome of early- vs late-onset ventilator-associated pneumonia (VAP) in medical intensive care unit (MICU).

Materials and methods

This prospective study was conducted on 273 patients admitted to the MICU in JIPMER, Puducherry, from October 2018 to September 2019.

Results

The incidence of VAP was 39.59 per 1000 ventilation days of MICU patients (93/273). Of these, 53 (56.9%) patients had early-onset VAP and 40 (43.1%) had late-onset VAP. Multiple logistic regression analysis showed that steroid therapy, supine head position, coma or impaired unconsciousness, tracheostomy, and re-intubation were found to be independent predictors of early- and late-onset VAP, respectively. Most cases of VAP were caused by Gram-negative bacteria (90.6%), with nonfermenters contributing to 61.8%. The most frequent pathogens causing early-onset VAP were Acinetobacter baumannii (28.9%) and Pseudomonas aeruginosa (20.6%), while in late-onset VAP, A. baumannii (32.9%) and Klebsiella pneumoniae (21.9%) were the most common. Maximum death rate was seen in patients infected with Escherichia coli (50%) and Stenotrophomonas maltophilia (38.5%). There was no significant association between the presence of VAP and mortality among the studied population.

Conclusion

The incidence of VAP in our study was high. There were no significant differences in the prevalence of pathogens associated with early-onset or late-onset VAP. Our study shows that early-onset and late-onset VAP have different risk factors, highlighting the need for developing different preventive and therapeutic strategies.

How to cite this article

Gunalan A, Sastry AS, Ramanathan V, Sistla S. Early- vs Late-onset Ventilator-associated Pneumonia in Critically Ill Adults: Comparison of Risk Factors, Outcome, and Microbial Profile. Indian J Crit Care Med 2023;27(6):411-415.

Clinical profile and risk factors for mortality in children admitted with diphtheria: an observational study

BACKGROUND

There is an ongoing resurgence of diphtheria infection worldwide despite a vaccine being available to prevent it for more than four decades.

OBJECTIVES

To study the clinical characteristics and risk factors for mortality of diphtheria cases among children 1-12 years of age treated in our hospital from 1 April 2014 to 31 March 2021.

METHODOLOGY

The data of hospitalised cases of childhood diphtheria from 1 April 2014 to 31 March 2019 were retrospectively analysed from the medical records department of our hospital. All hospitalised children with diphtheria from 1 April 2019 to 31 March 2021, were prospectively studied. All categorical variables were expressed as proportion/percentage and all continuous variables were expressed as median with interquartile range (IQR). Risk factors for morbidity and mortality were analysed and tested for significance. Unadjusted odds ratio (OR) was calculated and significant variables were subjected to multivariate logistic regression.

RESULTS

Of the 58 children with diphtheria, 62% were lab-confirmed, most cases (45%) were between 5 and 9 years of age. Majority (57%) were completely immunised as per the national immunisation schedule. Fever (97%) was the most predominant clinical symptom. The classical diphtheria pseudo membrane was identified in all. Respiratory failure was the most predominant complication, followed by myocarditis and acute kidney injury. The case fatality rate was 8.6%.

CONCLUSION

Diphtheria cases were seen among children 5-9 years of age more commonly. Infection requiring hospitalisation was seen in vaccinated children too. No atypical manifestations were observed. Complications of the disease adversely affected the overall survival.

Clinical Profile and Predictors of Mortality among Patients with Melioidosis

Introduction

Melioidosis is an under-recognized but important infection with high mortality and morbidity. It is endemic along the coastal regions of the Southern part of India. The present study focuses on the varied clinical manifestations, associated risk factors, and outcomes in patients from the Southeastern part of India.

Methods

Seventy patients from January 2018 to June 2021 from a Tertiary Care Hospital were included and prospectively followed up from 6 months to 3 years. Cox regression was performed to test for the association of various clinical and demographic factors with overall survival.

Results

Diabetes and occupational exposure to soil and water (78.6%) followed by alcoholism (61.4%) were the most common risk factors for melioidosis. The most frequent presentation was sepsis (47.1%), followed by skin and soft tissue infection (32.9%) and pneumonia (25.7%). Mortality was 50%. Patients with sepsis had a 3.5-fold higher risk of mortality (adjusted hazard ratio = 3.50; P = 0.01) while other risk factors were not significantly associated with mortality.

Conclusion

Lifestyle-dependent risk factors (diabetes, occupational exposure, and alcoholism) were most common among patients with melioidosis. Hospitalization among patients with sepsis is associated with high mortality despite the initiation of specific therapy.

Variable Virulence Genes in Clinical Isolates of Burkholderia pseudomallei: Impact on Disease Severity and Outcome in Melioidosis

Objectives To isolate Burkholderia pseudomallei from clinical specimens and study the association of virulence genes with clinical manifestations and outcome in patients with melioidosis.

Materials and Methods Burkholderia pseudomallei isolates obtained from melioidosis cases diagnosed during 2018 to 2021 were identified using VITEK 2 system and confirmed by polymerase chain reaction (PCR) targeting a Type III secretion system gene cluster. Multiplex PCR was performed to detect the genotypes of lipopolysaccharide (LPS) namely A, B, and B2, and singleplex PCR was performed to detect the presence of the Burkholderia intracellular motility gene (BimA) and filamentous hemagglutinin gene (fhaB3).

Statistical Analysis Chi-square/Fisher's exact tests were performed to study the association between various clinical manifestations and outcome and different virulence genes. The results were expressed as unadjusted odds ratios with 95% confidence intervals.

Results Sixty-seven isolates were available for characterization. BimABm and BimABp were observed among 82 and 18% of the isolates, respectively. Both sepsis and mortality were significantly associated with BimABm . Majority of the isolates had fhaB3 (97%). Most of the isolates showed the presence of LPS A gene (65.7%) followed by LPS B gene (6%), while LPS B2 was not detected. Nineteen isolates could not be assigned to any LPS genotypes.

Conclusion Among the virulence genes studied, only BimABm was significantly associated with sepsis and mortality. More than a quarter (28.3%) of the isolates could not be assigned to any LPS genotypes, hinting at a greater genetic diversity in our isolates.

Rare and unexpected cause for isolated massive pericardial effusion in a patient with end-stage renal disease—Brucellosis

Brucellosis is one of the most common zoonotic infections with worldwide distribution. The clinical presentation of brucellosis ranges from asymptomatic to severe disease involving haematological, gastrointestinal, neurological and osteoarticular systems. Cardiovascular manifestations are rare in brucellosis cases with endocarditis being the most common presentation. Isolated pericarditis with massive pericardial effusion without endocarditis is extremely rare. Here, we describe a case of brucellosis with sole manifestation of pericarditis with massive pericardial effusion in a patient with end stage renal disease diagnosed based on the isolation ofBrucella melitensisfrom pericardial fluid.

Assessment of Perinatal Clinical Characteristics, Perinatal Risk Factors, and Microbial Profile in Congenital Nasolacrimal Duct Obstruction in a Tertiary Care Center: A Descriptive Study

Purpose

To assess the perinatal risk factors, clinical characteristics, and microbial profile in congenital nasolacrimal duct obstruction (CNLDO).

Methods

A prospective observational study was conducted in pediatric patients of age <5 years. After a thorough clinical evaluation, the diagnosis of the CNLDO was confirmed by a Jones dye test or fluorescein dye disappearance test. A microbiological culture of lacrimal sac resurge was done with a sterile swab stick without touching the lid margins. Antibiotic susceptibility was then performed for the standard antibiotics.

Results

Seventy-one eyes of 52 children were included in the study. The mean age was 3.4 months. Our research found an equal number of cases born via spontaneous vaginal delivery and Caesarean section. Nine children (17.3%) had associated systemic and ocular anomalies. The number of cultures that were positive for any growth was 19 (27%). The most common isolate was Streptococcus pneumoniae which constituted eight cases (42%), followed by Pseudomonas aeruginosa (15.8%), and Escherichia coli (10.5%). Other organisms that grew were Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and nonfermenting gram-negative bacilli. Gram-positive organisms were susceptible to ciprofloxacin, amoxiclav, and oxacillin, and most of them were resistant to erythromycin. In comparison, gram-negative organisms showed 62.5% resistance and 37.5% susceptibility to ciprofloxacin.

Conclusions

CNLDO was more commonly unilateral, in male, preterm, and normal birth weight infants. Bilateral CNLDO was more commonly associated with coexisting ocular or systemic anomalies. Prematurity, delivery by Caesarean section, and presence of congenital anomalies were associated with a prolonged course. S. pneumoniae was the predominant isolate in our patient population.

Poor Sensorium at the Time of Intubation Predicts Polymicrobial Ventilator Associated Pneumonia

Background

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in the intensive care unit and is associated with a high mortality rate.

Aim

The study was conducted to estimate the frequency, outcomes, and predictors of polymicrobial VAP.

Methods

A prospective observational study was conducted in mechanically ventilated adult patients in the medical intensive care unit in a tertiary care hospital in India from July 2016 to July 2018 with a 30-day follow-up period. The patients were grouped into monomicrobial and polymicrobial VAP. We compared the 30-day outcome parameters such as discharge from hospital, in-hospital stay, death, and complications such as catheter associated urinary tract infection (CAUTI), central line associated blood stream infection (CRBSI), bacteremia and collapse of lung. The predictors of polymicrobial VAP were identified by multiple logistic regression.

Results

Out of 301 patients clinically diagnosed with VAP, 151 patients were excluded, and the remaining 150 developed 186 episodes of VAP during the study period. The incidence of polymicrobial VAP was 62.9%. Out of 150 patients, 51 patients had monomicrobial VAP, and 99 had polymicrobial VAP. On univariate analysis, diabetes mellitus and poor sensorium (Glasgow Coma Scale [GCS] score <8) during endotracheal intubation; 30-day outcome, mean days of mechanical ventilation after VAP diagnosis and days in ICU; and CAUTI were significantly associated with polymicrobial VAP. On multivariable logistic regression, poor sensorium (GCS score <8) at the time of endotracheal intubation was an independent predictor of polymicrobial VAP.

Conclusion

The incidence of polymicrobial VAP is high in the medical ICU and is associated with increased duration of mechanical ventilation, hospital stay, and incidence of CAUTI. Poor GCS score was the single independent predictor of polymicrobial VAP.

Detection of vancomycin variable enterococci (VVE) among clinical isolates of Enterococcus faecium collected across India-first report from the subcontinent

PURPOSE

Emergence of vancomycin variable enterococci (VVE) poses a challenge to empiric vancomycin therapy. Vancomycin-variable enterococci (VVE) are vanA-positive, yet phenotypically vancomycin-susceptible enterococci that can switch to a vancomycin-resistant phenotype when exposed to vancomycin. The aim of the present study was to determine the prevalence of VVE in India.

METHODS

Isolates of phenotypically vancomycin susceptible Enterococcus faecium from 20 tertiary care hospitals across India were collected and tested for the presence of vanA, vanR, vanS, vanB and vanC genes by conventional PCR using previously published primers. Isolates positive for vanA gene were considered as VVE.

RESULTS

The prevalence of VVE was 1.5% (5/340). Only one VVE isolate was positive for vanR and vanS, and all the isolates were negative for vanB and vanC.

CONCLUSIONS

Although the prevalence is low, our finding emphasizes the importance of routinely screening for van genes in enterococci that are phenotypically susceptible. Silenced vanA able to escape detection and revert to resistance during vancomycin therapy represents a new challenge in clinical settings.

Estimation of seroprevalence of melioidosis among adult high risk groups in Southeastern India by indirect Hemagglutination assay

Burkholderia pseudomallei is an environmental saprophyte known to cause melioidosis, a disease endemic in northern Australia and Southeast Asia. With the increasing number of melioidosis cases, there is a lack of data on seroprevalence rates and extent of exposure in high risk population of melioidosis from different endemic regions in India. The present cross sectional study was undertaken to estimate the seroprevalence of melioidosis in high risk populations in and around Puducherry, a coastal town in Southeastern India. Blood samples were collected from 275 diabetic individuals attending a tertiary care centre in Southern India and 275 farmers residing under the rural field practice area of our hospital. The antibody levels were estimated using an Indirect Hemagglutination Assay. The overall seropositivity was found to be 19.8% with a titer ≥1:20. Farmers were 2.8 times more likely to be seropositive than non-farmers. Rates of seroprevalence among diabetic subjects were less compared to the non-diabetic individuals. The seropositivity rates in non-diabetic farmers were higher (56/203, 27.6%) compared to diabetic farmers (34/164, 20.7%). The lowest seropositivity was seen among diabetic non-farmers at 10.4%. Multivariable logistic regression analysis revealed domicile (adjusted odds ratio-aOR: 2.32, 95% Confidence interval-CI: 1.05, 5.13) and contact with animals (aOR: 1.89, 95% CI:1.04, 3.44) as significant predictors of seropositivity. None of the other socio-demographic factors including gender and age were significantly associated with seropositivity. This study demonstrates widespread exposure to B. pseudomallei among adults residing in and around Puducherry, including those engaged in non-farming occupations.

Successful Isolation of Burkholderia pseudomallei from Soil by Extended Incubation of Ashdown’s Agar: A Cross-sectional Study

Introduction: Melioidosis is an infectious disease of humans and animals caused by an environmental saprophyte Burkholderia pseudomallei. Although the organism is associated with soil and water, environmental isolation is rarely successful which could be due to the existence of viable but non-culturable forms. Aim: To isolate B. pseudomallei from the soil to detect the environmental presence of this organism in and around Puducherry, India. Materials and Methods: A descriptive cross-sectional study was carried out from July 2018 to January 2021 at Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India. A total of 473 soil samples were collected from areas surrounding the residence and workplaces of seven culture-proven melioidosis cases, from Puducherry and three districts of Tamil Nadu (Cuddalore, Nagapattinam and Villupuram) during the dry and wet seasons. Soil samples were enriched in Ashdown’s broth and cultured on Ashdown’s agar. The plates were incubated at 37°C and examined daily for seven days with a further extended period of incubation till the tenth day for samples that did not show growth. Suspected isolates were subjected to Vitek 2 system for biochemical identification. Confirmation of the isolates was carried out by antigen detection and Polymerase Chain Reaction (PCR). Results: From 473 soil samples processed, bacteria with colony morphology similar to B. pseudomallei were isolated in 56 (11.83%) samples. Only one isolate, which was detected on the tenth day of incubation was confirmed as B. pseudomallei using antigen detection and PCR. This sample was collected during the wet season (December 2020) from Endur, in the Villupuram district of Tamil Nadu, India. Conclusion: The study findings highlight the importance of extended incubation of culture plates at 37°C for up to ten days to improve the chances of isolation from the soil.

Clinical profile, visual outcome and root cause analysis of post-operative cluster endophthalmitis due to Burkholderia cepacia complex

Purpose:

To present varied clinical presentations, surveillance reports, and final visual outcomes of a rare outbreak of cluster endophthalmitis caused by gram-negative, opportunistic bacilli, Burkholderia cepacia complex (Bcc).

Methods:

Details of five patients who developed postoperative cluster endophthalmitis were collected. For each patient, an undiluted vitreous sample was collected during vitreous tap. Bacterial culture from the vitreous sample in each case had grown Bcc. Surveillance investigations for root cause analysis (RCA) were performed in the operating room (OR), admission, and day-care wards to localize the source.

Results:

Four patients had undergone phacoemulsification surgery, and one patient had undergone penetrating keratoplasty. Each patient received an initial dose of empiric intravitreal ceftazidime and vancomycin. The organism isolated in each case was sensitive to ceftazidime, cotrimoxazole, and meropenem and resistant to other antibiotics. Core vitrectomy was done after 48–60 hours in four patients along with intravitreal imipenem injection. One patient did not provide consent for core vitrectomy and subsequently developed phthisis bulbi. Three patients had subsequent recurrences. Two patients had a final BCVA of 20/60, two had BCVA better than 20/200, while one patient had no perception of light. None of the surveillance samples from the OR complex could isolate Burkholderia.

Conclusion:

Extensive OR surveillance should be done to identify the potential source of infection. However, the source may not be identifiable in few instances like in our case. Longer follow-up is recommended in cases of Bcc endophthalmitis due to the persistent nature of the infection.

Isolation of Corynebacterium freneyi from a case of exudative pharyngitis, a close mimicker of Corynebacterium diphtheriae

Corynebacterium freneyi is a recently described coryneform bacteria. It is only rarely identified from clinical specimens and its pathogenic significance has not been well studied. Here we report the isolation of the species from the throat swab of a patient with suspected diphtheria. The morphology on direct microscopy and culture also closely resembled Corynebacterium diphtheriae, which almost led to misidentification. The prompt clinical and microbiological response suggests a probable pathogenic role. This is the first report of the isolation of this species from an oropharyngeal sample.

Pulmonary melioidosis complicating foreign body aspiration in a young adult

Melioidosis is caused by an environmental Gram-negative bacilli Burkholderia pseudomallei. Diabetes mellitus, occupational exposure to soil and water, pre-existing renal diseases and thalassemia are significant independent risk factors for melioidosis. A 30-year-old male carpenter and smoker had a history of accidental aspiration of foreign body 2 months prior. On presentation, he had cough with expectoration and low-grade intermittent fever for 1 month. His chest x-ray displayed left lower zone consolidation with cavitation and presence of foreign body in the left lower lobe bronchus. Bronchoalveolar lavage inoculated onto 5% sheep blood agar and MacConkey agar grew B. pseudomallei. Melioidosis due to foreign body aspiration is rare. To the best of our knowledge, there have not been reports of melioidosis infection associated with foreign body inhalation. Hence, pulmonary melioidosis can be considered as a differential diagnosis in cases of foreign body with secondary infection even in immunocompetent host.

Study of Conjunctival Microbial Flora in Patients of Intensive Care Unit

Purpose

The objective of the study was to evaluate the type of conjunctival microbial flora in intensive care unit patients and their antimicrobial sensitivity pattern.

Methods

A total of 272 samples (conjunctival swabs) were taken from patients in various intensive care units and sent for culture and sensitivity. An ocular examination was done to look for lagophthalmos, conjunctival discharge, exposure keratitis, and corneal perforation.

Results

Majority (82.1%) of the samples showed at least one microbial isolate while 29 (10.7%) samples showed multiple microbial growth. The most common microbes were coagulase negative Staphylococcus spp. (41.5% of isolates), diphtheroids (11.0% of isolates), and Staphylococcus aureus (9.6% of isolates) which are the usual commensals of the ocular surface. Of the other microbes isolated, Pseudomonas aeruginosa (4.0%) was the most common. Eighty-four percent isolates of coagulase negative Staphylococcus sp., 81.8% isolates of diphtheroids and 100% isolates of Staphylococcus aureus were penicillin resistant. All isolates of Enterococcus fecalis were sensitive only to vancomycin. Two hundred and twenty eyes (80.9%) had varying degrees of lagophthalmos. Nineteen (7.0%) had severe corneal exposure changes leading to infectious corneal ulcer and perforation in all of them.

Conclusions

The isolates in patients of intensive care units were no different from the normal conjunctival flora though few pathogenic organisms such as Pseudomonas aeruginosa and Acinetobacter sp. were also isolated. Most of the isolates were penicillin resistant. This knowledge will help take appropriate prophylactic measures to contain ocular infections in the intensive care units.

Effect of Peri-Operative Hyperoxygenation on Surgical Site Infection in Patients Undergoing Emergency Abdominal Surgery: A Randomized Controlled Trial

Background: The rationale for hyperoxygenation in controlling surgical site infection (SSI) has been described in many studies yet has not been defined clearly. Some studies in colorectal surgery have reported beneficial effects, whereas studies in gynecologic surgery have reported either no effect or a deleterious effect. This study assessed the effectiveness of hyperoxygenation on the reduction of SSI in patients undergoing emergency abdominal surgery. Patients and Methods: Eligible patients were assigned randomly to two groups (study group, 80% oxygen or control group, 30% oxygen). The patients in the study group received 80% oxygen and the patients in the control group received 30% oxygen intra-operatively and for two hours after surgery. Arterial blood gas analysis was done after resuscitation, at the end of the surgery, and at two hours after extubation. All patients were assessed for SSI, post-operative nausea and vomiting, and respiratory complications. Patients were followed post-operatively for 14 days. Surgical site infection was diagnosed according to U.S. Centers for Disease Control and Infection (CDC) criteria and by aerobic wound cultures. Results: After exclusion, 85 patients in the control group and 93 patients in the study group were analyzed. There was no difference for baseline, intra-operative, and post-operative characteristics between the two groups, except for higher oxygen saturation at closure and two hours post-operatively, in the 80% group (p = 0.01). Surgical site infection occurred in 29 patients (34.11%) in 30% fraction of inspired oxygen (F_IO₂) group and in 19 patients (20.43%) in 80% F_IO₂ group (p = 0.04). The risk of SSI was 59% lower in the 80% F_IO₂ group (adjusted odds ratio, 0.41; 95% confidence interval [CI], 0.19-0.88 vs. the 30% F_IO₂ group). There were no differences in post-operative nausea and vomiting and respiratory complications between the two treatment groups. Conclusions: Administration of 80% peri-operative hyperoxygenation in emergency abdominal surgery reduces SSI and is a cost-effective method.

Secondary Infections in Hospitalized COVID-19 Patients: Indian Experience

Purpose

Critically ill coronavirus disease 2019 (COVID-19) patients need hospitalization which increases their risk of acquiring secondary bacterial and fungal infections. The practice of empiric antimicrobial prescription, due to limited diagnostic capabilities of many hospitals, has the potential to escalate an already worrisome antimicrobial resistance (AMR) situation in India. This study reports the prevalence and profiles of secondary infections (SIs) and clinical outcomes in hospitalized COVID-19 patients in India.

Patients and Methods

A retrospective study of secondary infections in patients admitted in intensive care units (ICUs) and wards of ten hospitals of the Indian Council of Medical Research (ICMR) AMR surveillance network, between June and August 2020, was undertaken. The demographic data, time of infection after admission, microbiological and antimicrobial resistance data of secondary infections, and clinical outcome data of the admitted COVID-19 patients were collated.

Results

Out of 17,534 admitted patients, 3.6% of patients developed secondary bacterial or fungal infections. The mortality among patients who developed secondary infections was 56.7% against an overall mortality of 10.6% in total admitted COVID-19 patients. Gram-negative bacteria were isolated from 78% of patients. Klebsiella pneumoniae (29%) was the predominant pathogen, followed by Acinetobacter baumannii (21%). Thirty-five percent of patients reported polymicrobial infections, including fungal infections. High levels of carbapenem resistance was seen in A. baumannii (92.6%) followed by K. pneumoniae (72.8%).

Conclusion

Predominance of Gram-negative pathogens in COVID-19 patients coupled with high rates of resistance to higher generation antimicrobials is an alarming finding. A high rate of mortality in patients with secondary infections warrants extra caution to improve the infection control practices and practice of antimicrobial stewardship interventions not only to save patient lives but also prevent selection of drug-resistant infections, to which the current situation is very conducive.

Streptomyces pneumonia in an immunocompetent adult - a rare isolate

Streptomyces belongs to the Actinomycetes group of bacteria which are gram-positive non acid-fast bacilli, widely recognised for their potential to produce antimicrobials active against bacterial, mycobacterial, parasitic and fungal infections. They commonly cause cutaneous infections following traumatic inoculation. Visceral infections are relatively rare and limited to immunocompro-mised hosts. We describe a case of Streptomyces pneumonia in a healthy immunocompetent female, who when investigated for voluntary kidney donation, resulted in the isolation of Streptomyces species from bronchial wash cultures. Streptomyces, a potential pathogen in immunocompetent hosts is frequently underdiagnosed. Once isolated, both physicians and microbiologists should pay attention to differentiate true infection from contamination.

Does negative pressure wound therapy with saline instillation improve wound healing compared to conventional negative pressure wound therapy? - A randomized controlled trial in patients with extremity ulcers

BACKGROUND

Wounds are important health problems that cause significant financial burden and loss of time to work, more so in low and lower middle income countries. Negative pressure wound therapy (NPWT) is widely established in managing acute and chronic extremity wounds. We studied the effects of addition of normal saline instillation to NPWT in terms of changes in granulation tissue, bacterial-burden and overall wound healing using readily available means and materials including wall suction for negative pressure, sponge and adhesive transparent sheet for dressing and normal saline for irrigation.

METHODS

All patients with extremity ulcers initially underwent surgical debridement. They were then allotted into two groups, group 1 (NPWT with normal saline instillation- NPWTi) including 25 patients and group 2 (NPWT) including 23 patients. Tissue-bit samples taken on day1 and day 10 were used for bacteriology and for assessing histology. The wound surface-area was measured using the software ImageJ on day 1 and day 10.

RESULTS

Median log difference in colony-count between day1 and day10 was 0.6 (0.2-1.4) in group1 and 0.13 (0.04-0.6) in group 2 (p < 0.05). Mean percentage reduction in wound size was 28.82 and 19.80 in group 1 and group 2 respectively (p < 0.05). Histological parameters of wound healing assessed as surface epithelium, granulation, inflammatory cells, proliferative blood-vessels and fibroblasts were significantly better in group1. A drawback observed with NPWTi was skin maceration around the ulcer which was successfully managed.

CONCLUSION

Our findings suggest that wound healing is significantly better when saline instillation is combined with NPWT. It can aid in complex extremity ulcers management by reducing the size of the wound with healthier looking granulation tissue.

Concordance between the National Healthcare Safety Network (NHSN) Surveillance Criteria and Clinical Pulmonary Infection Score (CPIS) Criteria for Diagnosis of Ventilator-associated Pneumonia (VAP)

Background: Ventilator-associated pneumonia (VAP) is one of the most common hospital-acquired infections among mechanically ventilated patients and the incidence rates are widely used as an index of quality of care given in an ICU. Since there is no gold standard method available to diagnose VAP, the incidence rate varies based on different criteria used for calculation. Therefore, we conducted a study to determine the concordance between the National Healthcare Safety Network (NHSN) surveillance criteria and clinical pulmonary infection score (CPIS) criteria for the diagnosis of VAP.

Materials and methods: This was a prospective study that evaluated patients in the medical intensive care units (MICUs) of a tertiary care hospital, India, who were intubated for >48 hours between October 2018 and September 2019. All the patients (n = 273) were followed up daily and assessed using both CPIS and NHSN surveillance criteria for diagnosing VAP.

Results: Of these 273 patients, 93 patients (34.1%) had VAP according to CPIS criteria as compared with 33 patients (12.1%) using the NHSN criteria. The corresponding rates of VAP were 39.59 vs 11.53 cases per 1,000 ventilator days, respectively. The agreement of the two sets of criteria was fairly good (kappa statistics, 0.42)

Conclusion: The NHSN surveillance criteria have a lower sensitivity in detecting VAP cases and have to be modified to achieve better results.

How to cite this article: Gunalan A, Sistla S, Sastry AS, Venkateswaran R. Concordance between the National Healthcare Safety Network (NHSN) Surveillance Criteria and Clinical Pulmonary Infection Score (CPIS) Criteria for Diagnosis of Ventilator-associated Pneumonia (VAP). Indian J Crit Care Med 2021;25(3):296–298.

In-vitro synergistic activity of colistin and meropenem against clinical isolates of carbapenem resistant E.coli and Klebsiella pneumoniae by checkerboard method

CONTEXT

The emergence of drug resistant pathogens pose major threat to hospitalized patients as well as to the community associated with increased mortality and morbidity. The treatment of carbapenem resistant enterobacteriaceae, one of the top WHO priority pathogen remains a global issue. Combination therapy with different classes of antibiotics have been tried with the aim to reduce toxicity, to increase the efficacy of the drugs and to reduce resistance. The in-vitro synergy methods have to be carried out to determine whether the combination of those antibiotics are synergistic, antagonistic or additive.

AIMS

We have performed in-vitro synergy testing by checkerboard method for colistin -meropenem combination to determine whether the combination of the two antibiotics were synergistic or antagonistic.

METHODS AND MATERIAL

All the consecutive twenty five blood isolates of Escherichia coli and twenty five blood isolates of Klebsiella pneumoniae which were showing resistance to carbapenems by either disc diffusion or vitek 2 were collected over a period of 6 months and checkerboard method was performed.

STATISTICAL ANALYSIS USED

The reduction of MIC of colisin on combination with meropenem compared to MIC of colistin alone is analyzed by McNemar's chisquare test with the help of software Stata version 14 and p value < 0.05 is considered as significant.

RESULTS

56% of K. pneumoniae showed synergy and 44% showed additive/indifference results. For E. coli 40% showed synergy and 60% showed additive/indifference. None of the isolates of E. coli and K. pneumoniae showed antagonism. There was more than two fold reduction in MIC of colistin (significant) on combining withmeropenem.

CONCLUSIONS

The study results support the combination therapy to treat infections by multi-drug-resistant Klebsiela pneumoniae and Escherichia coli by in-vitro checkerboard testing method which inturn will be helpful for clinicians for judicious use of antimicrobials.

Corynebacterium amycolatum: an unusual cause of corneal ulcer

Here, we report a novel case of corneal ulcer in a 72-year-old patient with diabetes caused by Corynebacterium amycolatum This organism should not be ignored as a harmless commensal whenever it is isolated in pure form in repeat cultures of the specimen along with a leucocyte reaction in direct microscopic examination. Moreover, this organism is multidrug-resistant, so species identification of diphtheroids is important to start appropriate antibiotic therapy. There are very few published reports of ocular infection and none of corneal ulcer by this organism.

Endophthalmitis due to Delftia acidovorans: An unusual ocular pathogen

Endophthalmitis is a dreaded postoperative complication of cataract surgery. Delftia acidovorans is usually nonpathogenic and an unusual ocular pathogen. Isolated reports of delftia-associated sepsis, otitis media, endocarditis, keratitis, etc. exist in literature. We report a rare and unique case of delftia-related endophthalmitis in a 67-year-old male diagnosed 2 weeks after uneventful cataract surgery. He was treated successfully with core vitrectomy and intravitreal antibiotics. Microbiological evaluation of vitreous sample identified the causative organism as Delftia acidovorans. Post-vitrectomy fundus evaluation at 1 week revealed the presence of retinal vascular sheathing and sclerosis along with few retinal hemorrhages. Final visual recovery was poor due to the presence of macular edema, epiretinal membrane, and temporal disc pallor.

The impact of antimicrobial stewardship programme on regulating the policy adherence and antimicrobial usage in selected intensive care units in a tertiary care center - A prospective interventional study

Purpose

Antimicrobial resistance (AMR) presents a significant threat to human health. The root cause for this global problem is irrational antimicrobial usage. Antimicrobial stewardship (AMS) emphasises on the appropriate use of antibiotics and ensures strict implementation of antimicrobial policy guidelines. This study was conducted to evaluate the impact of auditing of AMS programme on regulating the antimicrobial policy adherence and antimicrobial usage in hospital intensive care units.

Materials and Methods

This was a prospective interventional study. It consisted of pre-implementation and implementation phases 6 months each. Two hundred and eighty patients were enrolled. Details of antibiotic consumption, surgical prophylaxis, culture/sensitivity patterns, de-escalation rates, etc., were collected in both phases. The implementation phase, in addition, included stewardship audit rounds.

Results

In pre-implementation phase and implementation phases: policy adherence rates were 23.7% and 41.8%, respectively, de-escalation rates were 22.73% and 43.48%, respectively. Cultures were sent before the initiation of antimicrobials in 36.73% cases during the pre-implementation phase, which improved to 60.41% during the implementation phase. Defined daily dose (DDD) for the antibiotics was 98.66 DDD 100BD during the pre-implementation phase, which reduced to 91.62 DDD 100BD in the implementation phase. Total days of therapy (DOT) in the pre-implementation phase were 561 DOT1000BD, which reduced to 463 DOT1000BD during the implementation phase.

Conclusions

Implementation of continuous monitoring of the AMS programme, therefore, has a definite role in reducing the antimicrobial consumption and improving the compliance to the policy guidelines. A more robust study for a prolonged period is, however, necessary to have a better analysis of the outcome.

Genetic sequencing of influenza A (H1N1) pdm09 isolates from South India, collected between 2011 and 2015 to detect mutations affecting virulence and resistance to oseltamivir

Background

Influenza A viruses evolve continuously and the two surface antigens, hemagglutinin (HA) and neuraminidase (NA) have been the target proteins for research as they are vital components in determining the virulence, immune effectiveness, pathogenicity, transmission and resistance.

Methods

Both HA and NA (partial genes) of 45 pandemic influenza A(H1N1)pdm09 isolates were sequenced. Phylogenetic analysis was performed with reference to representative global isolates retrieved from Influenza Virus Resource (IVR), GISAID EpiFluTM and GenBank and evolutionary analyses. Nucleotide and amino acid sequences were aligned using ClustalW/ Clustal Omega/MEGA version 6 with reference to vaccine strain (A/California/07/2009).

Results

All the isolates clustered along with the clade 7 virus, irrespective of the year of isolation. The study isolates exhibited 98.5% and 98.8% nucleotide homology to the reference strain A/California/07/2009(H1N1) for HA and NA, respectively. Overall, there was limited genetic diversity observed over a period of 3 years (2012-2015). Two samples collected from expired patients had D239N (D222G or D225G) mutation in HA. This mutation which is associated with dual-binding specificity of the virus has been well-correlated with severe disease outcomes. All the study isolates possessed H274 residue and 7 strains had N295S, the next most common mutation found in oseltamivir-resistant variants.

Conclusion

In this study, although H274Y mutation associated with oseltamivir resistance has not been noted, significant mutations have been noted in both HA and NA genes including D239N, N295S, V106I, Q136K, N248D, V267A. In both HA and NA gene analysis, multiple mutations were found more in 2015 strains when compared to 2012 strains. Hence such accumulation of mutations has to be monitored continuously to determine the efficacy of annual flu vaccines and anti-influenza drugs.

Epidemiology and phylogenetic analysis of respiratory viruses from 2012 to 2015 - A sentinel surveillance report from union territory of Puducherry, India

Background

Acute respiratory infections (ARI) are the most common illnesses affecting people of all ages worldwide. Viruses contribute to 30–70% of acute respiratory infections. Identification of these respiratory viruses is not given high priority except influenza; however, the knowledge about prevalence of non-influenza viruses, their seasonal pattern and genetic evolution have significant epidemiological value.

Methods

As a part of National Influenza-like illness surveillance programme, respiratory specimens were collected children and adults with symptoms of ILI or ARI, between January 2012 and March 2015 (including SARI cases). Real-time PCR was done to identify 13 respiratory viruses. Sequencing was done for representative isolates of each virus using ABI 3730 Genetic Analyzer.

Results

During the study period between January 2012 and March 2015, a total of 648 patients with symptoms of ARI were included in this study. The mean age of the patients was 20.2 years (SD = 19.13, median = 18); 292 (45.1%) were children (≤13 years) and 356 (54.9%) were adults. Respiratory viruses were identified in 44% (287/648) of all patients. Influenza accounted for the maximum number of cases- 179/648 (27.6%). Among the non-influenza viruses, RSV predominated with 34 cases (5.2%), followed by HMPV 24 (3.7%) and PIV-3 20 (3%). Four patients died due to INF A/H1N1 (2012-2, 2015-2) as a result of acute respiratory distress syndrome (ARDS) (CFR 3.7%). Among the non-influenza viruses, no particular seasonality pattern was observed over the different months of the study period.

Conclusion

Antibiotic usage in treating acute respiratory infections empirically is not justified as nearly half of ARI are due to viruses; nearly 28% of them were due to influenza viruses. Among the non-influenza viruses, RSV predominated, followed by HMPV. This study is based on an active influenza surveillance initiated after 2009 pandemic influenza outbreak, in the Union territory of Puducherry which has contributed significantly to the knowledge of the burden of influenza and non-influenza viruses among children and adults. Such surveillance network has paved the way for better diagnosis and timely therapeutic interventions.

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First data on the epidemiology of respiratory viruses from this region after 1974.

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First study to report corona virus, HCoV OC43 from India, and only the second Indian study to document corona virus, HCoV229E. This study is the first study to analyse the genetic sequence of HCoV-229E and OC-43.

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Influenza accounted for the maximum number of cases in the study population, 27%; four patients died of Acute respiratory distress syndrome (ARDS) due to influenza A/H1N1; CFR- 3.7%.

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Among the non-influenza viruses, RSV pre-dominated followed HMPV and PIV-3. No deaths were reported due to non-influenza viral ARI. RSV was detected almost equally in adults and children.

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Distinct pattern was observed in seasonality of influenza viruses but not for non-influenza viruses.

Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus: A preliminary report from south India

Background & objectives

Although there are reports of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) across the globe, there is a lack of reliable data on hVISA in India. The present study was undertaken to determine the rate of hVISA among the methicillin-resistant Staphylococcus aureus (MRSA) isolates, and to compare the brain heart infusion agar with vancomycin 4 μg/ml (BHIV4) method with population analysis profile-area under the curve (PAP-AUC) method for the detection of hVISA and to study the distribution of mobile genetic element that carries methicillin-resistance gene SCCmec (Staphylococcal cassette chromosome mec) types among these isolates.

Methods

BHIV4 and PAP-AUC methods were employed to detect hVISA among 500 clinical isolates of MRSA. SCCmec typing of these isolates was performed by multiplex polymerase chain reaction. The clinical presentation, treatment with vancomycin and outcome was documented for patients with hVISA.

Results

The rate of hVISA was 12.4 per cent by PAP-AUC method. Sensitivity, specificity, PPV, NPV and kappa agreement of BHIV4 with PAP-AUC was 58.06, 93.15, 54.55, 94.01 per cent and 0.498, respectively. The isolation of hVISA was significantly (P<0.01) higher in patients admitted to intensive care units and wards than in patients attending the outpatient departments. Only 38 per cent of the patients received vancomycin as therapy. Majority of the hVISA isolates carried SCCmec type V or IV.

Interpretation & conclusions

The rate of hVISA isolation in our study was 12.4 per cent. The sensitivity of the BHIV4 screening test was low, and was in moderate agreement with PAP-AUC test. SCCmec type V was the predominant type seen in half of the isolates. More studies need to be done in different parts of the country on a large number of isolates to confirm our findings.

Occurrence, predictors and outcome of infections at three months in hospitalized patients with SLE: A prospective study from Southern India

Prospective data on infections in systemic lupus erythematosus (SLE) from India are scarce. We studied the frequency and predictors of infections in hospitalized SLE patients. All data on infections were prospectively recorded. During the study period, 212 SLE patients (91% women) were hospitalised. Sixty-three (29.7%) had infections. The most common infections were pneumonia, skin and soft-tissue infections and urinary-tract infections. Mortality was higher in the infection group compared to the no infection group (11.1% vs. 0.7%; p=0.01). At three months, 10/63 developed another episode of infection. On logistic regression, the predictors of infection were fever [odds ratio (OR) = 4.17], vasculitis (OR = 2.64), thrombocytopaenia (OR = 3.59), presence of co-morbidities (OR = 3.59) and duration of hospital stay >11 days (OR = 3.55); p<0.001 for all. High-sensitivity CRP (hsCRP) and procalcitonin were measured in 95 patients. hsCRP was significantly higher in the infection group compared to the no infection group (median 27 vs. 6.5 mg/L; p<0.001). Procalcitonin was similar in both groups. A hsCRP of 11.5 mg/L had a sensitivity of 66.7% and specificity of 72.9% to diagnose infection. To conclude, 29.7% of Indian SLE patients who are hospitalized have infections, resulting in a significantly increased duration of hospital stay. The presence of fever and co-morbidities are predictors of infection. The role of high hsCRP to support the diagnosis of infection in SLE is once again confirmed.

Prevalence and Molecular Determinants of Antimicrobial Resistance in Clinical Isolates of Staphylococcus haemolyticus from India

Aims: Although Staphylococcus haemolyticus is considered as a part of normal skin flora, infections associated with them are increasing. Irrespective of the low virulence profile it poses a severe threat to patients with indwelling devices due to its multidrug-resistant nature. The aim of this study was to determine antibiotic resistance patterns and to detect the genes responsible in clinical isolates of S. haemolyticus. Results: All the 356 S. haemolyticus isolates were susceptible to glycopeptides. 91.3% were resistant to cefoxitin, 85.4% to erythromycin, 57.3% to co-trimoxazole, 52.8% to clindamycin, whereas only 3.7% of isolates were resistant to linezolid. Tetracycline resistance was found in 16.6% of isolates with tetK as the major genetic determinant. Most of the cefoxitin-resistant isolates carried mecA gene (99.4%), whereas dfrG gene was found only in 57.3% of co-trimoxazole-resistant isolates. Macrolides resistance was seen in 85.4% of isolates with cMLS_B (constitutive macrolide, lincosamide, and streptogramin B) (42.5%) as the major phenotype with ermC and msrAB genes as the predominant genetic determinants. Among linezolid-resistant isolates all except one showed higher minimum inhibitory concentration (MIC) (>256 μg/mL) with chloramphenicol-florfenicol resistance (cfr) gene as the genetic determinant, whereas one isolate had a lower MIC (16 μg/mL) and was negative for cfr gene. Conclusion: Emerging resistance to linezolid is a cause for concern. Strategies to prevent the spread of antibiotic resistance require continuous surveillance of these multidrug-resistant strains.

Aetiology and Short-Term Outcome of Acute Respiratory Distress Syndrome: A Real-World Experience from a Medical Intensive Care Unit in Southern India

Background

Acute respiratory distress syndrome (ARDS) is a highly fatal syndrome especially in resource constrained settings. In this study we prospectively studied the aetiology of ARDS and its short-term outcome.

Methods

Consecutive adults with suspected ARDS were screened. ARDS was diagnosed by the Berlin criteria. Aetiology was determined clinically, and by imaging and microbiological investigations. Patients presenting with fever, prominent cough and expectoration had a throat swab tested for influenza H1N1 virus. Outcome was discharge from hospital or death.

Results

A total of 42 patients, mean age 42.6 years, were studied. All received mechanical ventilation. Thirteen (31%) had pulmonary ARDS: H1N1 virus infection (n = 5), pneumonia (n = 7) and tuberculosis (n = 1). Twenty nine (69%) had extrapulmonary ARDS: sepsis (n = 16) and scrub typhus (n = 8). Thirty three (79%) died, of the nine survivors scrub typhus was diagnosed in seven patients.

Conclusion

The aetiology of ARDS in tropical medical setting is infection related. ARDS due to scrub typhus appeared to be mild with good outcome.

Risk factors for intestinal colonization with vancomycin resistant enterococci' A prospective study in a level III pediatric intensive care unit

PURPOSE:

Vancomycin-resistant enterococci (VRE) emerged as one of the major nosocomial pathogens across the globe. Gut colonization rate with VRE is higher in patients admitted to intensive care units (ICUs) due to the higher antibiotic pressure. VRE colonization increases the risk of developing infection up to 5–10 folds. The aim of this study was to determine the rates of VRE colonization among the patients admitted to pediatric ICU (PICU) and risk factors associated with it.

MATERIALS AND METHODS:

Rectal swabs were collected after 48 h of admission to PICU from 198 patients. The samples were inoculated onto bile esculin sodium azide agar with 6 mg/ml of vancomycin. Growth on this medium was identified by the standard biochemical test, and minimum inhibitory concentration of vancomycin and teicoplanin was detected by agar dilution method. Resistance genes for vancomycin were detected by polymerase chain reaction. Risk factors were assessed by logistic regression analysis.

RESULTS:

The rates of VRE colonization in patients admitted to PICU was 18.6%. The majority of the isolates were Enterococcus faecium (75.6%) followed by Enterococcus faecalis (24.4%). One patient acquired a VRE bloodstream infection (2.6%) among colonized patients, and none of the noncolonized patients acquired the infection. Consumption of vancomycin was found to be the only risk factor significantly associated with VRE colonization.

CONCLUSION:

Routine surveillance and isolation of patients found to be VRE colonized may not be possible in tertiary care hospitals; however, educating health-care workers, promoting handwashing with antiseptic soaps or solutions, and antibiotic Stewardship policy may help in the reduction of vancomycin resistance and VRE colonization.

Insertion sequences and sequence types profile of clinical isolates of carbapenem-resistant A. baumannii collected across India over four year period

OBJECTIVES

Acinetobacter baumannii emerged as a major nosocomial pathogen responsible for infections. In this study, we report the molecular characterization, association of insertion sequences and sequence types of clinical isolates of carbapenem resistant A. baumannii.

MATERIALS AND METHODS

A total of 763 non-duplicate isolates of A. baumannii received from 8 centres across India during January 2014 to December 2017 were studied. Susceptibility testing was done by Kirby-Bauer method. PCR was performed for detection of extended spectrum β-lactamases, metallo β-lactamases, oxacillinases and ISAba1. Mapping PCR was performed to identify the position of ISAba1 with respect to bla_OXA-23 like and bla_OXA-51 like gene. MLST was performed to identify the sequence type. Whole genome sequencing was done to decipher the genetic arrangement of ISAba1 with bla_OXA-23 like and with bla_OXA-51 like.

RESULTS

All the isolates were resistant to imipenem and meropenem. bla_OXA-23 like was the predominant carbapenemase. All isolates were positive for ISAba1. The common sequence types were ST848, ST451 and ST1305 which belongs to International clone II. Whole genome sequencing showed considerable variation in the insertion site location.

CONCLUSIONS

In conclusion, high prevalence of bla_OXA-23 like in A. baumannii and its association with ISAba1 and sequence types belonging to IC-II facilitates the successful dissemination of these extremely drug resistant strains.

Molecular characterization & epidemiology of carbapenem-resistant Acinetobacter baumannii collected across India

Background & objectives

Acinetobacter baumannii is an opportunistic pathogen responsible for causing nosocomial infections. A. baumannii develops resistance to various antimicrobial agents including carbapenems, thereby complicating the treatment. This study was performed to characterize the isolates for the presence of various β-lactamases encoding genes and to type the isolates to compare our clones with the existing international clones across five centres in India.

Methods

A total 75 non-repetitive clinical isolates of A. baumannii from five different centres were included in this study. All the isolates were confirmed as A. baumannii by bl a_OXA-51-likePCR. Multiplex PCR was performed to identify the presence of extended spectrum β-lactamases (ESBL) and carbapenemases. Multilocus sequence typing was performed to find the sequence type (ST) of the isolates. e-BURST analysis was done to assign each ST into respective clonal complex.

Results

bla_OXA-51-likewas present in all the 75 isolates. The predominant Class D carbapenemase was bla_OXA-23-likefollowed by Class B carbapenemase, bla_NDM-like. Class A carbapenemase was not observed. bla_PER-likewas the predominant extended spectrum β-lactamase. ST-848, ST-451 and ST-195 were the most common STs. Eight-novel STs were identified. e-BURST analysis showed that the 75 A. baumannii isolates were clustered into seven clonal complexes and four singletons, of which, clonal complex 208 was the largest.

Interpretation & conclusions

Most of the isolates were grouped under clonal complex 208 which belongs to the international clonal lineage 2. High occurrence of ST-848 carrying bla_OXA-23-likegene suggested that ST-848 could be an emerging lineage spreading carbapenem resistance in India.

Molecular characterization of extended-spectrum β-lactamases among clinical isolates of Escherichia coli & Klebsiella pneumoniae: A multi-centric study from tertiary care hospitals in India

Background & objectives:

The increasing prevalence of extended-spectrum β-lactamases (ESBLs) has abated therapeutic options worldwide. This study was undertaken to investigate the molecular profile and resistance patterns of ESBLs among clinical isolates of Escherichia coli and Klebsiella pneumoniae at four tertiary care centres in India.

Methods:

Clinical isolates of E. coli and K. pneumoniae were collected from the All India Institute of Medical Sciences (AIIMS), New Delhi; the Jawaharlal Institute of Postgraduate Medical Education & Research (JIPMER), Puducherry; Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh and Christian Medical College (CMC), Vellore, over one and a half year period. Antimicrobial susceptibility was determined by Kirby-Bauer disc diffusion method. ESBLs were confirmed phenotypically, and multiplex PCR was performed to identify genes for β-lactamases (bla_TEM, bla_SHV, bla_OXA-1, bla_CTXM-1, bla_CTXM-2, bla_CTXM-9 and bla_CTXM-15).

Results:

Among 341 E. coli isolates collected during the study period, 171 (50%) harboured bla_TEM, 145 (43%) bla_OXA-1, 70 (21%) bla_CTXM-1, 19 (6%) bla_SHV and four (1%) harboured bla_CTXM-2. Phenotypically, combined disc test detected ESBL production in 98/298 (33%) E. coli. Among 304 K. pneumoniae isolates, 115 (38%), 89 (29%), 83 (27%), 64 (21%) and two (0.6%) harboured bla_TEM, bla_OXA-1, bla_CTXM-1, bla_SHV and bla_CTXM-2, respectively. Combined disc test (CDT) detected ESBL production in 42 per cent K. pneumoniae. Most of the bla_CTXM-1 positive isolates were also bla_CTXM-15 positive. The carbapenem susceptibility ranged from 56 to 88 per cent for E. coli and from 20 to 61 per cent for K. pneumoniae. Antibiotic sensitivity patterns showed that colistin (CST) was the most sensitive drug for both E. coli (271/274, 99%) and K. pneumoniae (229/234, 98%).

Interpretation & conclusions:

The prevalence of ESBL among four study centres varied, and bla_TEM,bla_OXA-1 and bla_CTXM-15 were the most common genotypes in E. coli and K. pneumoniae isolates in India. The growing carbapenem resistance and emerging colistin resistance warrant the judicious use of these antimicrobials.

Establishing Antimicrobial Resistance Surveillance & Research Network in India: Journey so far

The Indian Council of Medical Research, in 2013, initiated the Antimicrobial Resistance Surveillance & Research Network (AMRSN) to enable compilation of data on six pathogenic groups on antimicrobial resistance from the country. The overarching aim of this network was to understand the extent and pattern of antimicrobial resistance (AMR) and use this evidence to guide strategies to control the spread of AMR. This article describes the conception and implementation of this AMR surveillance network for India. Also described are the challenges, limitations and benefits of this approach. Data from the Network have shown increasing resistance in Gram-negative bacteria in the hospitals that are part of this network. Combined resistance to third-generation cephalosporins and fluoroquinolones and increasing carbapenem resistance are worrisome, as it has an important bearing on the patients’ outcome and thus needs to be addressed urgently. Data generated through this Network have been used to develop treatment guidelines, which will be supportive in harmonizing treatment practices across the tertiary level healthcare institutions in the country. While, the major benefit of having a surveillance system is the collection of real-time accurate data on AMR including the mechanisms of resistance, representativeness to community, sustaining the current effort and expanding the current activities to next levels of healthcare settings are the major challenges. The data emanating from the network besides providing evidence, expose several gaps and lacunae in the ecosystem and highlight opportunities for action by multiple stakeholders.

Validation of pneumococcal iron acquisition (piaA) gene for accurate identification of Streptococcus pneumoniae

Purpose

The pneumococcal iron acquisition (piaA) gene is found to be highly specific and hence proposed as a diagnostic marker for identification of pneumococci. The objective of the present study was to evaluate the piaA gene as a genetic marker for the identification of pneumococci.

Methods

Twenty isolates were initially sequenced for lytA gene using published primers. PiaA-PCR (piaA polymerase chain reaction) was performed using in-house primers and protocol. Based on the sensitivity and specificity results, a final sample of 30 pneumococcal isolates and 11 non-pneumococcal isolates confirmed with lytA- sequencing were selected. Statistical analyses were performed using OpenEpi v3.01 and GraphPad Quickcalc at P < 0.05 as the level of statistical significance.

Results

Of the initial 20 samples tested, piaA PCR was positive in only 71.43% (10/14) of the pneumococcal isolates but was 100% specific (0/6 non-pneumococcal isolates) P = 0.011. When the PCR was performed on 41 samples, the sensitivity increased to 73.33% (95% of confidence interval [CI] = 55.55-85.82) and specificity remained the same P < 0.001. The level of agreement between the PCR and lytA-sequencing was found to be moderate (κ = 0.694; 95% CI = 0.432-0.955).

Conclusions

PiaA-PCR can be used as a specific marker for the identification of pneumococcus, though it is less sensitive. As the level of agreement was moderate, further analyses on a large number of samples can give conclusive evidence for its use as a diagnostic marker for pneumococcus.

Decoding the molecular epidemiology of group A streptococcus - an Indian perspective

PURPOSE

Unlike western countries the knowledge of group A streptococcus (GAS) epidemiology in India remains patchy and incomplete. Typing is crucial for surveillance as well as in predicting the efficacy of multivalent M protein vaccine. The present study aimed to explore the emm types of 206 invasive and non-invasive GAS isolates from South India as well as reviewing all the published literature on GAS molecular epidemiology from India thereby generating a pan-Indian data to predict the conjectural coverage of the 30-valent M-protein vaccine in this population.

METHODOLOGY

emm typing and superantigen (SAg) profiling of GAS along with reviewing literatures on GAS molecular epidemiology from India.

RESULTS

This study revealed a high diversity of emm types with emm 63, 82, 183, 85, 92, 169, 42, 44, 106, 74, 12 being frequently encountered, belonging to twenty emm clusters. The pan-Indian data on prevalent emm types further supports our study findings with 135 emm different types. Six clusters dominated accounting for 80 % of the GAS isolates: E3(26 %), E6(20 %), E2(11 %), E4(10 %), D4(7 %), E1(6 %). No significant association was noted between emm types and the nature of infection (P≥0.05) while a few SAg profiles were significantly associated with certain emm types. Pan Indian data revealed that only 16 % of the emm types encountered were included in proposed 30-valent M protein based vaccine.

CONCLUSION

The coverage among the South Indian GAS isolates was 28.2 % which increased to only 46.6 % with the cross-opsonic effect, thus highlighting the importance of developing a specific multivalent vaccine including the prevalent emm types in India or considering the use of conserved C-repeat vaccines and non-M protein based vaccines.

Association of spontaneous expulsion with C-reactive protein and other clinico-demographic factors in patients with lower ureteric stone

The purpose of our study is to analyze the definitive relation of C-reactive protein (CRP) and other factors with the spontaneous stone passage in patients with distal ureteric calculus of 5-10 mm and to calculate the risk of failure of expectant management in patients. 185 patients of ureteric colic, who were subjected to medical expulsive therapy (MET), were included prospectively from August 2016 to May 2018 and followed up for 4 weeks. Patients were divided into two groups. Group A included successful spontaneous passage patients and group B included failure in the same. The parameters analyzed were age, gender, longitudinal and transverse diameter of stone, CRP, total leucocyte count, ureteric diameter and hydroureteronephrosis (HUN). We performed univariate and multivariate analysis. Receiver operating characteristics curve was used to determine the cutoff value for significantly associated variables. 122 (65.90%) and 63 (34.10%) patients were included in group A and B, respectively. In univariate analysis, CRP, longitudinal and transverse diameter of stone, HUN, proximal and distal ureteric diameters were statistically significant. However, in multivariate analysis, only negative CRP (p = 0.002), smaller longitudinal diameter of stone (p < 0.001) and absence of HUN (p = 0.005) were significantly associated with successful expulsion. Cutoff for CRP was 0.41 mg/dl and longitudinal diameter was 6.7 mm. The success rate in the group of patients with no risk factor was 96.7% and with all three risk factors was 16.7%. Patients with a longitudinal diameter of stone > 6.7 mm, HUN, and CRP > 0.41 mg/dl should be considered for early intervention. The success rate of MET can be increased to 86% after exclusion of patients with all three risk factors.

Existence of multiple SCCmec elements in clinical isolates of methicillin-resistant Staphylococcus aureus

PURPOSE

Methicillin-resistant Staphylococcus aureus (MRSA) can be classified into hospital-acquired MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA), based on the associated epidemiological risk factors and their SCCmec types. We therefore studied the diversity and distribution of SCCmec elements among MRSA isolates in our region and also evaluated SCCmec typing as a tool for the classification of MRSA.

METHODOLOGY

Two hundred isolates of MRSA obtained from various clinical specimens were included. The clinical and demographic details of the patients and the epidemiological risk factors for MRSA acquisition were documented. Multiplex PCR was optimized for all the major SCCmec types (I to V). Subtyping of SCCmec type IV (IVb, IVc, IVd, IVh) was carried out by simplex PCR.

RESULTS

Based on epidemiological criteria, CA-MRSA constituted 57  % (114/200) of the the test isolates and HA-MRSA made up 43  % (86/200). The predominant SCCmec type found in our study was type III (62%), followed by type V (52.5%) and type I (47.5%), while type II was carried by a single isolate. Of the 200 isolates, 118 carried multiple SCCmec types and 3 were non-typable.

CONCLUSION

The existence of multiple SCCmec types in individual MRSA isolates resulted in our inability to categorize many of these isolates as either CA-MRSA or HA-MRSA as defined by the SCCmec type criterion.

LIMITATION

The major limitation of the study was that the SCC mec element of MRSA isolates exhibiting multiple types was not sequenced and hence this finding could not be confirmed.

Rare isolation of Fusobacterium varium from a case of Fournier's gangrene

Fusobacterium is a gram negative obligate anaerobic bacilli, a normal inhabitant of gastrointestinal tract, oropharynx and female genital tract. Here we report a case of Fourniers gangrene from which Fusobacterium varium has been isolated along with certain other pathogens. There are only a few reported cases of Fusobacterium varium in literature and it has never been reported from Fournier's gangrene. Through this report we intend to shed some light on the pathogenic potential of anaerobes which are considered as normal flora.

Dominance of international high-risk clones in carbapenemase-producing Pseudomonas aeruginosa: Multicentric molecular epidemiology report from India

Background

Pseudomonas aeruginosa is one of the most common opportunistic pathogens that cause severe infections in humans. The burden of carbapenem resistance is particularly high and is on the rise. Very little information is available on the molecular mechanisms and its clonal types of carbapenem-resistant P. aeruginosa seen in Indian hospitals. This study was undertaken to monitor the β-lactamase profile and to investigate the genetic relatedness of the carbapenemase-producing (CP) P. aeruginosa collected across different hospitals from India.

Materials and Methods

A total of 507 non-duplicate, carbapenem-resistant P. aeruginosa isolated from various clinical specimens collected during 2014-2017 across seven Indian hospitals were included. Conventional multiplex polymerase chain reaction for the genes encoding beta-lactamases such as extended-spectrum beta-lactamase (ESBL) and carbapenemase were screened. A subset of isolates (n = 133) of CP P. aeruginosa were genotyped by multilocus sequence typing (MLST) scheme.

Results

Of the total 507 isolates, 15%, 40% and 20% were positive for genes encoding ESBLs, carbapenemases and ESBLs + carbapenemases, respectively, whilst 25% were negative for the β-lactamases screened. Amongst the ESBL genes, bla_VEB is the most predominant, followed by bla_PER and bla_TEM, whilst bla_VIM and bla_NDM were the most predominant carbapenemases seen. However, regional differences were noted in the β-lactamases profile across the study sites. Genotyping by MLST revealed 54 different sequence types (STs). The most common are ST357, ST235, ST233 and ST244. Six clonal complexes were found (CC357, CC235, CC244, CC1047, CC664 and CC308). About 24% of total STs are of novel types and these were found to emerge from the high-risk clones.

Conclusion

This is the first large study from India to report the baseline data on the molecular resistance mechanisms and its association with genetic relatedness of CP P. aeruginosa circulating in Indian hospitals. bla_VIM- and bla_NDM-producing P. aeruginosa is the most prevalent carbapenemase seen in India. Majority of the isolates belongs to the high-risk international clones ST235, ST357 and ST664 which is a concern.