Staphylococcus aureus bacteremia in an Indian tertiary care hospital: observational study on clinical epidemiology, resistance characteristics, and carriage of the Panton-Valentine leukocidin gene

Dry and liquid formulations of IBT-V02, a novel multi-component toxoid vaccine, are effective against Staphylococcus aureus isolates from low-to-middle income countries

Staphylococcus aureus is the leading cause of skin and soft tissue infections (SSTIs) in the U.S. as well as more serious invasive diseases, including bacteremia, sepsis, endocarditis, surgical site infections, osteomyelitis, and pneumonia. These infections are exacerbated by the emergence of antibiotic-resistant clinical isolates such as methicillin-resistant S. aureus (MRSA), highlighting the need for alternatives to antibiotics to treat bacterial infections. We have previously developed a multi-component toxoid vaccine (IBT-V02) in a liquid formulation with efficacy against multiple strains of Staphylococcus aureus prevalent in the industrialized world. However, liquid vaccine formulations are not compatible with the paucity of cold chain storage infrastructure in many low-to-middle income countries (LMICs). Furthermore, whether our IBT-V02 vaccine formulations are protective against S. aureus isolates from LMICs is unknown. To overcome these limitations, we developed lyophilized and spray freeze-dried formulations of IBT-V02 vaccine and demonstrated that both formulations had comparable biophysical attributes as the liquid formulation, including similar levels of toxin neutralizing antibodies and protective efficacy against MRSA infections in murine and rabbit models. To enhance the relevancy of our findings, we then performed a multi-dimensional screen of 83 S. aureus clinical isolates from LMICs (e.g., Democratic Republic of Congo, Palestine, and Cambodia) to rationally down-select strains to test in our in vivo models based on broad expression of IBT-V02 targets (i.e., pore-forming toxins and superantigens). IBT-V02 polyclonal antisera effectively neutralized toxins produced by the S. aureus clinical isolates from LMICs. Notably, the lyophilized IBT-V02 formulation exhibited significant in vivo efficacy in various preclinical infection models against the S. aureus clinical isolates from LMICs, which was comparable to our liquid formulation. Collectively, our findings suggested that lyophilization is an effective alternative to liquid vaccine formulations of our IBT-V02 vaccine against S. aureus infections, which has important implications for protection from S. aureus isolates from LMICs.

Staphylococcus hemolyticus: The Most Common and Resistant Coagulase-Negative Staphylococcus Species Causing Bacteremia in North India

INTRODUCTION

Coagulase-negative Staphylococcus (CoNS) species are normal skin commensals but may also cause bacteremia. Therefore, isolating a CoNS species on blood culture often leads to a diagnostic dilemma about whether to consider the isolate as a true pathogen or not. This study was done to understand the distribution of various CoNS species in bloodstream infections, determine their antibiotic resistance patterns, and identify possible risk factors and patient outcomes in hospital settings.

MATERIALS AND METHODS

Inpatients with confirmed bacteremia defined as isolation of the same CoNS species with similar antibiograms from paired blood culture bottles, which were obtained from patients with at least clinical evidence of infection, were included. The isolates obtained were studied for CoNS species distribution and antibiotic resistance patterns, and the corresponding patients were assessed for possible risk factors and outcomes.

RESULTS

A total of 170 CoNS isolates obtained from 85 patients were analyzed. Staphylococcus haemolyticus (S. haemolyticus)(90, 52.9%) was the most common species isolated, and it was also the most resistant of all, followed by S. hominis (50, 29.4%), S. epidermidis (26, 15.3%), S. lentus (2,1.2%), and S. succinus (2,1.2%). S. haemolyticus and S. hominis were significantly more isolated from patients aged 18-60 years and >60 years, respectively. Methicillin-resistant (MR)-CoNS (68.8%) were significantly more resistant than methicillin-sensitive (MS)-CoNS (31.2%) to certain antibiotics, and none were resistant to vancomycin, linezolid, or teicoplanin. Mortality occurred in 17.6% of patients, which was most commonly associated with S. haemolyticus infection.

CONCLUSION

Age-specific predisposition of CoNS species, high rates of methicillin resistance, and mortality in CoNS bacteremia are highlights of this study. To our knowledge, we are the first to study the age-related association of CoNS species.

A prospective study on skin and soft tissue infections: a fact-finding mission from a tertiary centre in north India

OBJECTIVE

Despite the high prevalence and poor outcome of skin and soft tissue infections (SSTIs), very few studies from India have dealt with the subject. We planned a prospective study of inpatients with SSTIs to study the aetiology, clinical presentation (severity) and outcome of patients with SSTIs in our facility.

METHOD

Patients with SSTIs involving >5% body surface area (BSA) and/or systemic signs were admitted to the surgery department of a teaching tertiary level hospital in Delhi, India, and were clinically classified into cellulitis, necrotising soft tissue infections (NSTIs), pyomyositis, and abscess. Demographic and clinical variables such as: age; sex; occupation; history of trauma/insect or animal bites; duration of illness; presenting symptoms and signs; comorbid conditions; predisposing factors such as lymphoedema or venous disease; hospital course; treatment instituted; complications; hospital outcome; presence of crepitus, bullae, gangrene, muscle necrosis and compartment syndrome were recorded. The chief outcome parameters were death and length of hospital stay; others, such as abscess drainage, the need for plastic surgical procedures and amputations were also noted.

RESULTS

Out of 250 patients enrolled in the study, 145 (58%) had NSTIs, 64 (26%) had abscesses, 15 (6%) had cellulitis and 26 (10%) had pyomyositis. Mortality was observed with NSTIs (27/145, 19%) and with pyomyositis (3/26, 11.5%). Factors affecting mortality by univariate analysis in the NSTI group were: abnormal pulse; hypotension; tachypnea; bullae; increased blood urea and serum creatinine; inotrope or ventilator support (all with p<0.001); local tenderness, gangrene, dialysis support and BSA (9.33±6.44 versus 5.12±3.62; p<0.05 for the last four). No factor was found to be significant on multivariate analysis. Variables associated with hospital stay >12 days were immunocompromise, pus discharge, ulceration or gangrene, and after interventions such as blood transfusion, drainage or skin grafting.

CONCLUSION

High prevalence of NSTI and pyomyositis with high mortality was observed in our SSTI patients, often in immunocompetent young individuals. Epidemiological studies focused on virulent strains of Staphylococcus aureus may be required to identify the cause, since Staphylococcal toxins have been implicated in other infections.

Preventable contributors to the neonatal healthcare-associated infections: a uni-center analytical study from South India

Background: Globally, neonatal healthcare-associated infections (HAIs) are known to cause high mortality. HAIs is a preventable condition related to the healthcare environment. The current study explored the contributors to neonatal HAIs in one of the largest tertiary care referral hospitals in South India.

Methods: Neonates from December 2016 to June 2018 were observed for the occurrence of healthcare-associated infections and compared with the matched control group. Various observations on neonatal demography, maternal contributors, and medical procedures were made and recorded to explore and analyse the contributors to neonatal HAIs. Univariate and multivariate analysis was carried out to find the contributors. The Odds ratio with 95% CI was also computed and reported.

Results: Bloodstream infection (83%) was prevalent among neonates; the maternal contributor was only preterm labor (Odds ratio of 11.93; 95% CI; 6.47-21.98; p<.05) to acquire HAIs. On univariate analysis, mechanical ventilation for > 3days duration, NIV for > five days, and PICC line insertion procedure were significant (p<0.05) contributors to neonatal HAIs. IV cannulation for more than three times in four consecutive days was found in 100(85%) neonates considered being associated with neonatal HAIs. On multivariate analysis, NIV, PICC line, preterm labor, and low birth weight were significant (p<0.05) contributors to neonatal HAIs.

Conclusion: The increased duration of invasive and non-invasive therapeutic devices and catheters contributes to neonatal HAIs. Neonates are acquiring bloodstream infections; low birth weight (LBW) neonates are more susceptible to acquiring HAIs.

Staphylococcus aureus Vaccine Research and Development: The Past, Present and Future, Including Novel Therapeutic Strategies

Staphylococcus aureus is one of the most important human pathogens worldwide. Its high antibiotic resistance profile reinforces the need for new interventions like vaccines in addition to new antibiotics. Vaccine development efforts against S. aureus have failed so far however, the findings from these human clinical and non-clinical studies provide potential insight for such failures. Currently, research is focusing on identifying novel vaccine formulations able to elicit potent humoral and cellular immune responses. Translational science studies are attempting to discover correlates of protection using animal models as well as in vitro and ex vivo models assessing efficacy of vaccine candidates. Several new vaccine candidates are being tested in human clinical trials in a variety of target populations. In addition to vaccines, bacteriophages, monoclonal antibodies, centyrins and new classes of antibiotics are being developed. Some of these have been tested in humans with encouraging results. The complexity of the diseases and the range of the target populations affected by this pathogen will require a multipronged approach using different interventions, which will be discussed in this review.

Community-acquired bacterial pneumonia in adults: An update

Community-acquired pneumonia (CAP) is the prominent cause of mortality and morbidity with important clinical impact across the globe. India accounts for 23 per cent of global pneumonia burden with case fatality rates between 14 and 30 per cent, and Streptococcus pneumoniae is considered a major bacterial aetiology. Emerging pathogens like Burkholderia pseudomallei is increasingly recognized as an important cause of CAP in Southeast Asian countries. Initial management in the primary care depends on clinical assessment while the hospitalized patients require combinations of clinical scores, chest radiography and various microbiological and biomarker assays. This comprehensive diagnostic approach together with additional sampling and molecular tests in selected high-risk patients should be practiced. Inappropriate therapy in CAP in hospitalized patients lengthens hospital stay and increases cost and mortality. In addition, emergence of multidrug-resistant organisms poses tough challenges in deciding empirical as well as definitive therapy. Developing local evidence on the cause and management should be a priority to improve health outcomes in CAP.

Bacteriological Profile and Antibiotic Sensitivity Pattern of Clinical Isolates in a Tertiary Cancer Care Center in the Northeast India

Background  This study was performed to determine the bacteriological profile and antibiotic sensitivity pattern of culture samples of patients with cancer at our institute. The study was undertaken to formulate an antibiotic policy for the treatment of infection in these patients. Materials and Methods  The study was performed in the Department of Microbiology of a regional cancer center during the period from January 2017 to December 2017. Samples were collected under all aseptic precaution, and they were processed as per the Clinical and Laboratory Standard Institute Guideline 2017. Results  A total of 464 clinical samples (urine, blood, sputum, pus, etc.) were collected and processed for culture, of which 198 (42.67%) samples showed culture positive that were identified as per standard recommended procedures and antibiotic susceptibility testing was performed on isolates as per the Clinical Laboratory Standard Institute guidelines 2017. Escherichia coli (48), Staphylococcus aureus, (45) Klebsiella pneumoniae (52), Coagulase-negative Staphylococcus (17), and Pseudomonas aeruginosa (15) were most commonly encountered. Of the 132 Gram-negative isolates, 101 (76.5%) were extended-spectrum β-lactamase producers. Among the 45 staphylococcal isolates, 18 (40%) were methicillin-resistant S . aureus. Conclusion  The present study reveals microbiological profile in patients attending our cancer institute.

A Systemic Literature Review and Meta-Analysis Reporting the Prevalence and Impact of Methicillin-Resistant Staphylococcus aureus Infection in India

Aim and objective

This systematic review and meta-analysis was conducted to assess the prevalence, burden and epidemiology of methicillin-resistant S. aureus (MRSA). This systemic review was also aimed to highlight the challenges in the diagnosis and management of methicillin-resistant S. aureus (MRSA) in India (for all age groups). We also examined the published literature on the available treatment options and the role of prevention in the management of MRSA in India. By summarizing the currently available data, our objectives were to highlight the need for the prevention of MRSA infections and also emphasize the role of vaccination in the prevention of MRSA infections in India.

Methodology

Electronic databases such as PubMed and databases of the National Institute of Science Communication and Information Resources and Indian Council of Medical Research Embase were searched for relevant literature published from 2005/01/01 to 2020/05/13 in English language, according to the predefined inclusion and exclusion criteria. A manual search was also conducted using the key term "MRSA 'or' Methicillin Resistant Staphylococcus aureus 'and' India." An independent reviewer extracted data from the studies using a structured Microsoft Excel spreadsheet, and a meta-analysis of proportion for MRSA prevalence with a corresponding 95% confidence interval (CI) for all included individual studies were performed.

Result

A total of 34 studies involving 16 237 patients were included in the final meta-analysis. The pooled proportion of patients with MRSA infection was 26.8% (95% CI: 23.2%-30.7%). The MRSA infection was more prevalent among male patients (60.4%; 95% CI: 53.9%-66.5%) as compared to female patients (39.6%; 95% CI: 33.5%-46.1%), while the prevalence of MRSA was higher among adults (18 years and above; 32%; 95% CI: 5%-80%) in comparison to pediatric patients (0-18 years; 68%; 95% CI: 20%-94.8%). The degree of heterogeneity was found to be significant.

Conclusion

The prevalence of MRSA in India was relatively high at 27% with a higher proportion observed among men aged >18 years. The high prevalence of MRSA infections in India necessitates the implementation of surveillance and preventive measures to combat the spread of MRSA in both hospital and community settings.

Methicillin-resistant Staphylococcus aureus in Intensive Care Unit Setting of India: A Review of Clinical Burden, Patterns of Prevalence, Preventive Measures, and Future Strategies

Aim

The aim of this review article is not only to analyze the clinical burden of methicillin-resistant Staphylococcus aureus (MRSA) in intensive care unit (ICU) setting of India, along with the patterns of prevalence and its prevention measures, but also to focus on the new anti-MRSA research molecules which are in late stage of clinical development.

Background

Methicillin resistance is reported to be present in 13–47% of Staphylococcus aureus infections in India. Therapeutic options to combat MRSA are becoming less, because of emerging resistance to multiple classes of antibiotics. Intensive care units are the harbinger of multidrug-resistant organisms including MRSA and are responsible for its spread within the hospital. The emergence of MRSA in ICUs is associated with poor clinical outcomes, high morbidity, mortality, and escalating treatment costs. There is an urgency to bolster the antibiotic pipeline targeting MRSA. The research efforts for antibiotic development need to match with the pace of emergence of resistance, and new antibiotics are needed to control the impending threat of untreatable MRSA infections.

Review results

Fortunately, several potential antibiotic agents are in the pipeline and the future of MRSA management appears reassuring.

Clinical significance

The authors believe that this knowledge may help form the basis for strategic allocation of current healthcare resources and the future needs.

How to cite this article

Mehta Y, Hegde A, Pande R, Zirpe KG, Gupta V, Ahdal J, et al. Methicillin-resistant Staphylococcus aureus in Intensive Care Unit Setting of India: A Review of Clinical Burden, Patterns of Prevalence, Preventive Measures, and Future Strategies. Indian J Crit Care Med 2020;24(1):55–62.

Overview of methicillin resistant Staphylococcus aureus mediated bone and joint infections in India

Staphylococcus aureus is the most common pathogen causing bone and joint infections (BJI). In India, prevalence of Methicillin resistant Staphylococcus aureus (MRSA) is increasing at an alarming rate and emerged as an important contributor towards the difficult to treat BJI. Currently available anti-MRSA agents have their own limitations with regards to reduced susceptibility as well as safety and tolerability. Furthermore, biofilms over the prosthesis with invariably multi-drug resistant strains leads to complex treatment processes. This necessitates the need to develop and screen new antibiotics against MRSA that can easily penetrate the deep pockets of infection and take care of the challenges discussed. This review aims to discuss on MRSA infection in bone and joint infection, current antibiotic regimen, its associated limitations, and finally, the need to develop new antibiotic therapy for effective management of patients with BJI.

Is methicillin-resistant Staphylococcus Aureus infection associated with higher mortality and morbidity in hospitalized patients? A cohort study of 551 patients from South Western India

Purpose

To determine morbidity and mortality of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) infections in a tertiary health care facility.

Methods

A cohort study among hospitalized adult patients with culture proven MRSA or MSSA monoinfection were recruited in a tertiary referral center in South India from November 2011 to December 2012.

Results

Of total 551 subjects, 284 (52%) had MRSA and 267 (48%) MSSA infection. A total of 184 (65%) subjects had health care-associated MRSA (HA-MRSA) and 100 (35%) community-associated MRSA (CA-MRSA). Chronic kidney disease and recent antibiotic use had significant association with MRSA. MRSA patients had significant respiratory infection (OR 2.24 [1.04, 5.16]) and bacteremia (OR 2.24 [10.40, 5.16]), relative to MSSA. MSSA group had better survival function compared to MRSA group (P=0.028). Median duration of ICU stays were 5 days (IQR 4, 8) and 2 days (IQR 2, 2) in MRSA and MSSA, respectively. Complications such as acute kidney injury, sepsis, multiorgan dysfunction, need for supportive measures were more in the MRSA group.

Conclusion

MRSA imposes a huge burden in Indian scenario and HA-MRSA remains the main culprit. Patients with history of chronic kidney disease and recent use of antibiotics were found to be at a higher risk. Patients with MRSA infections tend to have poorer outcomes in terms of longer hospital stay, greater complications, and mortality.

Managing pulmonary embolism secondary to suppurative deep vein thrombophlebitis due to community-acquired Staphylococcus aureus in a resource-poor setting

Deep vein thrombosis and pulmonary thromboembolism are rare and life threatening emergencies in children. We report an 11-year old female who presented with acute complaints of high grade fever, pain in the left thigh and inability to walk and breathlessness since 6 days. On physical examination, there was a diffuse tender swelling of the left thigh, tachypnea, tachycardia with hyperdynamic precordium and bilateral basal crepitations. Ultrasonography and venous doppler of lower limbs showed mild effusion of left hip joint and thrombus in the left common femoral vein and left external iliac vein suggesting a diagnosis of septic arthritis with thrombophlebitis. The tachypnea and tachycardia which was out of proportion to fever and crepitations on auscultation prompted suspicion of an embolic phenomenon. Radiograph of the chest revealed multiple wedge shaped opacities in the right middle zone and lower zone suggestive of pulmonary embolism and left lower zone consolidation. For corroboration, computed tomography pulmonary angiography and computed tomography of abdomen was performed which showed pulmonary thromboembolism and deep venous thrombosis extending up to infrarenal inferior vena cava. On further workup, magnetic resonance imaging of hips showed left femoral osteomyelitis and multiple intramuscular abscesses in the muscles around the hip joint. Blood culture grew methicillin resistant Staphylococcus aureus. Antibiotics were changed according to culture sensitivity and there was a dramatic response. After four weeks of anticoagulation and antibiotics the child became asymptomatic and thrombus resolved. Thus, it is crucial to consider methicillin resistant Staphylococcus aureus infection as an important infection when we encounter such a clinical scenario. This case report highlights an unusual and potentially life threatening presentation of a virulent strain of a common pathogen, which when diagnosed was completely amenable to treatment.

Molecular characterization of Panton-Valentine leukocidin (PVL) toxin-encoding phages from South India

A total of 19 methicillin-resistant Staphylococcus aureus (MRSA) isolates were investigated for Panton-Valentine leukocidin (PVL) toxin, PVL gene sequence variation and PVL-encoding phages. Whole genome sequencing was performed for all isolates. Analysis of MRSA isolates (n = 19) confirmed that most MRSA (n = 11) were positive for the PVL gene and were multidrug resistant. ST772-MRSA-V was the predominant PVL-positive MRSA clone, although all of them were found to carry the ΦIND772PVL phage in the genome. This study provides insights into the evolution of a new lineage of PVL-MRSA and highlights the potential risk of the emergence of multidrug-resistant community-acquired MRSA with high virulence.

Diagnosis and management of Panton-Valentine leukocidin toxin associated Staphylococcus aureus infection: an update

The incidence of invasive Staphylococcus aureus (SA) infection has increased in the past decade and is associated with poor outcomes and high mortality rates. Of all the virulence factors, Panton-Valentine Leukocidin (PVL) has received the greatest attention. PVL producing SA strains are more likely to produce severe skin and soft tissue infections (SSTIs) and necrotizing pneumonia. This review focuses on the current evidence on PVL-SA virulence, epidemiology, clinical disease and treatment with relevance to healthcare in India.

Antibiotic Sensitivity and Clinico- epidemiological Profile of Staphylococcal Infections

This hospital-based study describes the antibiotic sensitivity of 66 S. aureus isolates from the admitted children (age 0-18 y) in a tertiary hospital of Kolkata, India. Methicillin-resistant S. aureus constituted 16.7% (n=11) of the isolates. Clindamycin-resistance was observed in 60% and 82% of methicillin-sensitive and methicillin-resistant strains, respectively.

Bacteriological profile and antibiotic susceptibility patterns of clinical isolates in a tertiary care cancer center

Introduction:

This increased risk of bacterial infections in the cancer patient is further compounded by the rising trends of antibiotic resistance in commonly implicated organisms. In the Indian setting this is particularly true in case of Gram negative bacilli such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. Increasing resistance among Gram positive organisms is also a matter of concern. The aim of this study was to document the common organisms isolated from bacterial infections in cancer patients and describe their antibiotic susceptibilities.

Methods:

We conducted a 6 month study of all isolates from blood, urine, skin/soft tissue and respiratory samples of patients received from medical and surgical oncology units in our hospital. All samples were processed as per standard microbiology laboratory operating procedures. Isolates were identified to species level and susceptibility tests were performed as per Clinical Laboratory Standards Institute (CLSI) guidelines -2012.

Results:

A total of 285 specimens from medical oncology (114) and surgical oncology services (171) were cultured. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter spp. were most commonly encountered. More than half of the Acinetobacter strains were resistant to carbapenems. Resistance in Klebsiella pneumoniae to cephalosporins, fluoroquinolones and carbapenems was >50%. Of the Staphylococcus aureus isolates 41.67% were methicillin resistant.

Conclusion:

There is, in general, a high level of antibiotic resistance among gram negative bacilli, particularly E. coli, Klebsiella pneumoniae and Acinetobacter spp. Resistance among Gram positives is not as acute, although the MRSA incidence is increasing.

Prevalence of Panton-Valentine leukocidin-positive methicillin-susceptible Staphylococcus aureus infections in a Saudi Arabian hospital

Panton-Valentine leukocidin (PVL) is a two-component toxin associated with the toxicity and virulence of Staphylococcus aureus. The presence of PVL is well documented in community-acquired methicillin-resistant S. aureus (CA-MRSA) and is observed in methicillin-susceptible S. aureus (MSSA) with variable prevalence. We assessed the prevalence of PVL in a sample of 93 MSSA patients in a healthcare facility in Eastern Saudi Arabia using real-time PCR for lukSF-PV genes. The presence or absence of PVL was correlated with age, gender, hospitalization status, infection site and antibiotic resistance. PVL was detected in 28 (30%) patient samples. PVL was associated with a greater likelihood of resistance to trimethoprim-sulfamethoxazole (a resistance of 39.2% of PVL-positive isolates compared to 6.1% of PVL-negative isolates) (p < 0.0007). These results suggest a significant prevalence of PVL expression in MSSA strains in the study population and call for monitoring of and surveillance programs for PVL status and the selection of appropriate antibiotic treatments.