Atypical Presentation Resembling Acute Leukoencephalopathy With Restricted Diffusion in Staphylococcus aureus Meningoencephalitis

Meningoencephalitis refers to inflammation of the brain and meninges. It can be caused by various organisms, such as Neisseria meningitidis, Streptococcus pneumoniae, and so on. Staphylococcus aureus causing meningoencephalitis is relatively rare. It is mainly encountered in patients who have undergone surgeries in the past. Acute leukoencephalopathy with restricted diffusion (ALERD) is a type of encephalopathy that can involve both white and grey matter of the brain, and it has a characteristic "bright tree appearance" on MRI. It can be because of various infectious etiologies or caused by various toxins. Neurological sequelae are observed in about two out of three cases. Here, we describe a case of S. aureus meningoencephalitis with ALERD, which has been seldom reported. More awareness about this is required among primary care physicians for timely diagnosis and management to prevent any complications.

The Prevalence and Antimicrobial Susceptibility of Methicillin-Resistant Staphylococcus aureus Before and After the COVID-19 Pandemic in a Tertiary Saudi Hospital

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) has become a major public health problem all over the world. After the 2019 coronavirus illness (COVID-19), the pandemic may have influenced research priorities and resource allocation, potentially affecting the ability to monitor MRSA trends.

AIMS

The study aimed to evaluate the prevalence of S. aureus, including MRSA infections, and their antimicrobial susceptibilities over the years 2019 and 2020 in a tertiary hospital in Makkah City, KSA.

METHODOLOGY

A total of 2128 and 1515 laboratory (lab) samples were collected during the years 2019 and 2020, respectively. From these samples, the prevalence of S. aureus, including MRSA, and their antibiotic susceptibility were identified using standard, automated, and molecular microbiological methods.

RESULTS

The present study shows that the lab prevalence of all S. aureus during 2019 was found to be 35.5%, of which MRSA was 44.8%. During 2020, the frequency of S. aureus strains was 16%, of which MRSA was 41.2%. The most common MRSA isolated during both years were colonizing pus swabs and urine samples. The results showed that MRSA susceptibility against antimicrobial agents in 2019 was as follows: vancomycin (100%), linezolid (100%), trimethoprim-sulfamethoxazole (88%), and doxycycline (34.2%). The MRSA strains isolated during 2020 were as follows: vancomycin (100%), linezolid (96%), trimethoprim-sulfamethoxazole (100%), and doxycycline (24.3%). There was no significant difference in the incidence and antimicrobial resistance rates of MRSA over the two years.

CONCLUSION

It was concluded that the prevalence rates of MRSA have not increased in 2020 when compared to 2019. Vancomycin, linezolid, trimethoprim-sulfamethoxazole, and doxycycline remain susceptible to the positive collected MRSA strains. There was no significant difference between the prevalence and antimicrobial resistance rates of MRSA between 2019 and 2020. Continued research efforts are needed to address this persistent public health threat. Strategies to control the spread of MRSA should include early detection of MRSA and surveillance, even during pandemics.

Deciphering the Neuropsychiatric Lupus Enigma: Navigating the Intersection of Acute Inflammatory Demyelinating Polyneuropathy (AIDP), Infection, and Flare

A 17-year-old male diagnosed with systemic lupus erythematosus (SLE), showing poor compliance with medication, presented to our facility with a 20-day history of fever, polyarthritis, and cough. Additionally, he had experienced a seizure episode, followed by a one-day history of altered mentation. Subsequently, he developed pneumonia, respiratory distress, and shock, necessitating ventilator and inotropic support. Neuropsychiatric lupus (NP-lupus) was suspected, and hence high-dose steroids, hydroxychloroquine, and broad-spectrum antibiotics were initiated. Following successful extubation, he manifested ascending flaccid paralysis. The presence of albumin-cytological dissociation and axonal neuropathy confirmed the diagnosis of acute inflammatory demyelinating polyneuropathy (AIDP). He underwent further management with pulse steroids and plasmapheresis. Upon recovery, he was discharged on a regimen of steroids, cyclophosphamide, and hydroxychloroquine. During follow-up, he maintained ambulatory status with no residual neurological sequelae.

Antimicrobial and Anti-Biofilm Activities of Coffea arabica L. Against the Clinical Strains Isolated From Diabetic Foot Ulcers

Diabetes-related complications such as diabetic foot infections foster resilient biofilms, complicating treatment. Innovative therapeutic solutions are urgently needed to address this challenge. In this research, coffee bean powder (green coffee been powder [GCBP], roasted coffee bean powder [RCBP], and spent coffee powder ground [SCPG]) was extracted and assessed for its ability to impede biofilm formation and associated functions in extended-spectrum beta-lactamase (ESBL) and methicillin-resistant Staphylococcus aureus (MRSA)-positive biofilm-forming strains of Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) obtained from foot ulcers. GCBP exhibited notable effectiveness in reducing biofilm formation, ranging from 17-76% in monocultures and 17-66% in mixed cultures. It significantly disrupted motility in P. aeruginosa and E. coli, a crucial factor influencing biofilm establishment. The critical biofilm-related functions for attachment and maintenance such as cell surface hydrophobicity and exopolysaccharide production were significantly inhibited at sub-MICs. Notably, GCBP elicited statistically significant reductions (29-59% in monocultures and 28-45% in mixed cultures) in pre-formed biofilms. The reduction in bacterial chitinase activity upon exposure to GCBP implies a potential mechanism for its ability to inhibit biofilm formation. This study emphasizes the potential of green coffee bean extract in tackling antibiotic-resistant bacterial biofilms associated with diabetic foot ulcers, suggesting innovative strategies for infection management through mechanistic understanding and optimized applications.

Comparison of genotyping methods and toxin gene profiles of Staphylococcus aureus isolates from clinical specimens

Staphylococcus aureus is a frequent cause of infections worldwide. Methicillin-resistant S. aureus (MRSA) is one of the main causes of Gram-positive infections, and methicillin-susceptible strains (MSSA) primarily colonize and infect community hosts. Multiple virulence factors are involved, with toxins playing a significant role in several diseases. In this study, we assess the prevalence of toxin genes in 89 S. aureus clinical isolates (31 MRSA and 58 MSSA). We evaluated the discriminatory power of the association of internal transcribed spacer-PCR (ITS-PCR) and 3'- end coa gene ( coa-PCR) when compared with other more commonly used and costly techniques. The isolates showed a high level of genetic diversity, and toxins were found in all the isolates. While most toxin classes displayed no statistically significant correlations and were equally distributed in isolates regardless of their resistance status, classic enterotoxins ( sea-see) showed a positive correlation with MSSA isolates. The combination of coa-PCR with ITS-PCR showed a discriminatory index of 0.84, discriminating 22 genotypes that agree with previously determined data by PFGE and MLST. This association between the two PCR-based methods suggests that they can be useful for an initial molecular epidemiological investigation of S. aureus in hospitals, providing significant information while requiring fewer resources.

Evaluation of In-Vitro Activity of Ceftaroline Against Methicillin-Resistant Staphylococcus aureus Clinical Isolates

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of hospital and community-acquired infections. Fewer drugs, such as vancomycin, teicoplanin, and daptomycin, are effective against it, but they come with high toxicity. Fifth-generation cephalosporins like ceftaroline and second-generation cefuroxime are effective against MRSA. Limited studies are available on ceftaroline resistance in the literature. This study was undertaken to determine ceftaroline resistance in MRSA in a tertiary care hospital in Eastern India. A cross-sectional, hospital-based study was carried out with MRSA isolates obtained from various clinical samples of patients. Identification of the isolates to the species level was performed by an automated Vitek system, and selected samples were genotypically confirmed by detecting the mecA gene via real-time PCR. Out of a total of 334 Staphylococcus aureus isolates examined in this study, the prevalence of MRSA was seen in 59.3% (198/334), and methicillin-sensitive Staphylococcus aureus was in 40.7% (136/334). Of the total 198 MRSA isolates, ceftaroline intermediate MRSA was seen in 8.6% (17/198), and ceftaroline sensitive MRSA was in 91.4% (181/198), respectively. Among the 17 ceftaroline intermediate MRSA isolates, 88.2% (15/17) showed a minimum inhibitory concentration (MIC) of 2 µg/ml, and 11.8% (2/17) showed an MIC of 3 µg/ml. All the remaining 91.4% (181/198) isolates were sensitive to ceftaroline and showed an MIC ≤1 µg/ml. Real-time PCR confirmed the presence of the mecA gene in MRSA isolates. In this present study, not a single isolate was resistant to ceftaroline, suggesting that it, being a safer drug, can be used in place of glycopeptides such as vancomycin or teicoplanin and linezolid, where resistance has already been detected. The rational use of ceftaroline could be useful in clinical settings, and further studies will confirm the findings.

An Unusual Case of Phagocytic Histiocytes on Peripheral Blood Smear of a Patient With Methicillin-Resistant Staphylococcus aureus (MRSA) Endocarditis

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder of the immune system that may rapidly progress into life-threatening complications. There is uncontrolled activation of histiocytes and phagocytic macrophages, resulting in excess secretions of cytokines that manifest into systemic hyperinflammation affecting several organs. HLH may present as primary due to underlying familial or genetic causes or as secondary due to underlying conditions such as malignancies, infections, or autoimmune disorders. This case is of a seven-year-old girl who developed culture-proven MRSA infective endocarditis. She received sensitivity-tailored antimicrobial treatment. Initially unremarkable, but later her peripheral blood smear showed the presence of large histiocyte-like cells showing hemophagocytic activity of moderate grade (two to five histiocytes with hemophagocytosis/slide) on the feathered edge of the slide. Peripheral film findings triggered further workup for HLH. Her condition later deteriorated, requiring high-dependency unit care. This case highlights the significance of maintaining a high index of suspicion with subsequent laboratory work in cases that develop cardinal diagnostic criteria for clinical manifestations of HLH. It also emphasizes reviewing the feathered edges of blood smears to prevent overlooking important morphological findings.

Clinical rel mutations in Staphylococcus aureus prime pathogen expansion under nutrient stress

Persistent infection by Staphylococcus aureus has been linked to the bacterial stringent response (SR), a conserved stress response pathway regulated by the Rel protein. Rel synthesizes (p)ppGpp "alarmones" in response to amino acid starvation, which enables adaptation to stress by modulating bacterial growth and virulence. We previously identified five novel protein-altering mutations in rel that arose in patients with persistent methicillin-resistant S. aureus bacteremia. The mutations mapped to both the enzymatic and regulatory protein domains of Rel. Here, we set out to characterize the phenotype of these mutations to understand how they may have been selected in vivo. After introducing each mutation into S. aureus strain JE2, we analyzed growth, fitness, and antibiotic profiles. Despite being located in different protein domains, we found that all of the mutations converged on the same phenotype. Each shortened the time of lag phase growth and imparted a fitness advantage in nutritionally depleted conditions. Through quantification of intracellular (p)ppGpp, we link this phenotype to increased SR activation, specifically during the stationary phase of growth. In contrast to two previously identified clinical rel mutations, we find that our rel mutations do not cause antibiotic tolerance. Instead, our findings suggest that in vivo selection was due to an augmented SR that primes cells for growth in nutrient-poor conditions, which may be a strategy for evading host-imposed nutritional immunity. Importance Host and pathogen compete for available nutrition during infection. For bacteria, the stringent response (SR) regulator Rel responds to amino acid deprivation by signaling the cell to modulate its growth rate, metabolism, and virulence. In this report, we characterize five rel mutations that arose during cases of persistent methicillin-resistant Staphylococcus aureus bacteremia. We find that all of the mutations augmented SR signaling specifically under nutrient-poor conditions, enabling the cell to more readily grow and survive. Our findings reveal a strategy used by bacterial pathogens to evade the nutritional immunity imposed by host tissues during infection.

Microbiological profile of bloodstream infections and antimicrobial resistance patterns at a tertiary referral hospital in Amazon, Brazil

BACKGROUND

Bloodstream infections (BSI) are a global health issue, leading to high mortality and morbidity among hospitalized patients.

METHODS

A retrospective, observational and descriptive study was conducted by reviewing blood culture records collected from patients with suspected BSI, between January 2017 and December 2019.

RESULTS

The most frequent antimicrobial resistant (AMR) pathogens were methicillin-resistantStaphylococcus aureus(MRSA) (40%), methicillin-resistantS. epidermidis (MRSE) (9.5%), and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (35.3%).

CONCLUSIONS

Our findings underscore the importance of continued vigilance and advocate for the rational use of antimicrobial agents.

Misleading Procalcitonin in Patients With Staphylococcus aureus Bacteremia: A Report of Two Cases

Procalcitonin (PCT) is an important biomarker for bacterial infection with a high negative predictive value. It is almost always positive in patients who are bacteremic with pathogenic bacteria. Here, we report two cases of Staphylococcus aureus bacteremia, where PCT levels were unexpectedly negative. This uncommon occurrence challenges the assumption of PCT's infallibility as a diagnostic marker in patients with true bacteremia. The first case is a 55-year-old woman with no past medical issues who presented with one week of generalized weakness and two days of fever and chills. Though her white blood cell (WBC) count and c-reactive protein (CRP) were elevated, PCT was normal, with no apparent source of infection, and hence antibiotic differed. However, her blood cultures returned positive for methicillin-resistant Staphylococcus aureus (MRSA). The patient was started on vancomycin and discharged on daptomycin, she responded appropriately and improved. The second case is an intravenous (IV) drug user, a 40-year-old woman, who presented with septic arthritis and osteomyelitis involving the right hip. She had blood cultures positive for methicillin-susceptible Staphylococcus aureus (MSSA); however, a PCT check on the day of positive blood cultures and various occasions subsequently was normal. These two cases remind us that we cannot over-rely on one test to rule out bacterial infection and should consider the whole clinical picture. They highlight the need for vigilance among clinicians that PCT can rarely be negative in cases of true bacteremia in spite of its high negative predictive value. Physicians and antibiotic stewardship programs should be cautious and aware of this potential pitfall when utilizing PCT as a diagnostic tool.

An Interesting Case of Methicillin-Resistant Staphylococcus aureus Prostate Abscess in an Immunocompetent Patient

Prostate abscess is a rare complication of prostatitis, typically observed in patients with conditions such as immunodeficiency, diabetes, urinary tract abnormalities, and chronic indwelling catheters. Gram-negative bacteria such as Enterobacteriaceae are the most commonly detected organisms in prostate abscesses. Methicillin-resistant Staphylococcus aureus (MRSA) infections are rarely reported. The unique aspect of our case involves MRSA bacteria, further complicated by an MRSA prostate abscess, in a 61-year-old immunocompetent male. The patient, with a past medical history of hypertension and diabetes, presented to the emergency department complaining of nausea and vomiting for four days, with an associated subjective fever and right-sided abdominal pain. A computed tomography (CT) scan of the abdomen/pelvis with contrast showed a prostatic abscess, with abscess/phlegmon extending bilaterally into the seminal vesicles. Urine and blood cultures were positive for MRSA. Initially, Piperacillin/Tazobactam and Vancomycin were initiated. Subsequently, the treatment was switched to Daptomycin. The patient also underwent cystoscopy with urethral dilation, transurethral prostate resection, and unroofing. Although MRSA is not a typical causative agent of prostatitis, it should be considered in the differential diagnosis, especially when clinical improvement cannot be achieved with standard empirical treatment. Timely identification and appropriate treatment (such as drainage and antibiotics) are crucial for both patient survival and the prevention of complications.

A Previously Healthy Infant with Lemierre Syndrome in the Emergency Department: Case Report

INTRODUCTION

Lemierre syndrome (LS) is a rare condition with a high mortality risk. It is well described in older children and young adults involving bacteremia, thrombophlebitis, and metastatic abscess commonly due to Fusobacterium infections. Young, pre-verbal children are also susceptible to LS; thus, careful attention must be given to their pattern of symptoms and history to identify this condition in the emergency department (ED).

CASE REPORT

A 12-month-old previously healthy boy with a recent diagnosis of acute otitis media and viral illness presented to the ED with a complaint of fever. Additional symptoms developed at the head and neck and were noted on subsequent ED visits. Advanced imaging revealed significant lymphadenopathy and deep space inflammation extending to the mediastinum. Subsequent imaging confirmed extensive sinus and deep vein thromboses, consistent with LS. Methicillin-resistant Staphylococcus aureus (MRSA) was the only organism identified. After surgical debridement, appropriate intravenous antibiotics, and heparin anticoagulation therapy, the patient experienced full recovery after prolonged hospitalization.

CONCLUSION

A febrile infant with multiple acute care visits and development of lymphadenopathy, decreased oral intake, decreased cervical range of motion, and sepsis should raise suspicion for Lemierre syndrome. The medical evaluation of deep neck spaces and deep veins should be similar to that of older children and adults with LS, including advanced imaging of the head and neck. However, medical management should particularly target MRSA due to its emerging prevalence among infantile LS cases. Further research is necessary to determine the optimal management strategies of LS for this age group.

Gradenigo's Syndrome and Vernet Syndrome as Presenting Signs of Nasopharyngeal Carcinoma

Both Gradenigo's syndrome and Vernet syndrome are rare pathologies of the intracranial space; both involve compression of a particular anatomic location in the skull, thus affecting structures nearby or within that space. A patient presenting with one or both of these syndromes should raise concern for malignancy, head trauma, or an intracranial infection. We present a case of a 39-year-old female with three weeks of left-sided ear, face, and neck pain along with difficulty swallowing and reduced vision in the left eye. Magnetic resonance imaging of the brain revealed fullness in the left nasopharyngeal region, raising concern for malignancy or infection. Biopsy of the mass ultimately revealed Epstein-Barr virus positive nasopharyngeal carcinoma, nonkeratinizing undifferentiated type, along with culture data revealing methicillin-resistant Staphylococcus aureus positive left otomastoiditis. She received chemoradiation therapy along with six weeks of antibiotic therapy. A patient presenting with symptoms reflective of a sinus infection unrelieved by antibiotics with concomitant cranial nerve deficits should raise clinical concern for an intracranial pathology rather than a simple case of sinusitis.

Neck Abscess Due to Pocket Shot: Is It Just the Tip of the Iceberg?

A 45-year-old Caucasian male presented to the emergency department for pain and swelling on the left side of his neck for the past 10 days. His medical history revealed that he was an intravenous (IV) drug abuser. Physical examination demonstrated a 5×5 cm red, swollen bump with a positive fluctuation on the left supraclavicular area concerning for an abscess. Fluid aspiration from the abscess was performed, and three sets of blood cultures were obtained, which later all came back positive for methicillin-resistant Staphylococcus aureus (MRSA). His initial blood tests revealed elevated levels of platelets, leukocytes, and C-reactive protein (CRP) and anemia. The computed tomography (CT) scan showed an enlarged pectoralis major with the presence of air. The retrosternal, infraclavicular, and supraclavicular regions also contained air. The clinical diagnosis was therefore supported by the laboratory results and imaging. Additionally, transthoracic echocardiography showed no vegetations, and transesophageal echocardiography was scheduled. Antibacterial treatment was initiated empirically from the emergency room with meropenem and vancomycin, planned for four weeks. Repeat cultures were obtained for the following three days, which were all negative. However, the patient left the hospital against medical advice and did not complete his antibiotic treatment. The risk of a peripherally inserted central catheter (PICC) line being misused for illegal narcotics was considered too high; hence, it was not recommended for continued IV antibiotic therapy at home. Those with a history of intravenous drug use, after using the most accessible injection sites, oftentimes resort to finding alternative and potentially more dangerous injection sites. The major veins of the neck, such as the jugular, subclavian, or brachiocephalic veins, are commonly used. This technique is referred to as a "pocket shot" by intravenous drug abusers (IVDAs). Apart from the apparent abscess, clinicians should oversee for other complications including underlying pus collections, pneumothorax, mediastinitis, osteomyelitis, and hemothorax.

Targeted Transcriptional Analysis of IgA Vasculitis, IgA Nephropathy, and IgA-Dominant Infection-Related Glomerulonephritis Reveals Both Distinct and Overlapping Immune Signatures

Key Points

Skin IL-9, calprotectin, and KIR gene expression may be predictive of subsequent kidney involvement in patients with IgAV. Histologically similar patients with IgAN, IgAV, and IgA-IRGN can be distinguished by their immune transcriptomes. Kidney biopsies from patients with IgA-IRGN are enriched for transcripts involved in granulocyte chemotaxis.

Background

IgA vasculitis (IgAV), IgA nephropathy (IgAN), and IgA-dominant infection-related glomerulonephritis (IgA-IRGN) have shared histopathologic features, but differences in clinical management and prognosis. The most serious IgAV organ involvement is in the kidneys (IgAV nephritis). In this study, we hypothesized that targeted immune transcript profiling could aid in (1 ) predicting the development of IgAV nephritis in patients with cutaneous IgAV and (2 ) differentiating IgAN, IgAV, and IgA-IRGN.

Methods

RNA was extracted from 24 formalin-fixed paraffin-embedded tissue specimens (16 kidney, 8 skin) from 21 patients with IgAV nephritis (n=7), IgAN (n=5), and IgA-IRGN (n=4), and IgAV skin biopsies from patients with (n=3) and without (n=5) IgAV nephritis. Differential gene expression and gene set enrichment analysis were performed on a total of 594 transcripts (Nanostring immunology panel) profiled using the nCounter system.

Results

Skin biopsies in patients with IgAV who develop kidney involvement exhibit reduced S100A8/S100A9 , IL9 , and killer cell immunoglobulin-like receptor expression. The kidney tissue immune transcriptomes of IgAN, IgAV, and IgA-IRGN are largely overlapping. IgA-IRGN kidney biopsies are, however, uniquely enriched for transcripts involved in granulocyte chemotaxis.

Conclusion

This study identifies immune transcript signatures that may predict IgAV nephritis in skin biopsies and distinguish IgA-IRGN from IgAN and IgAV in kidney biopsies.

Methicillin-Resistant Staphylococcus aureus (MRSA) Empyema Post-COVID Infection Causing Severe Septic Shock and Multiorgan Failure

Secondary bacterial infections post-COVID infection posed a major challenge to the healthcare settings during the COVID pandemic. We present the case of an 81-year-old patient who was initially admitted for COVID pneumonia in a tertiary care hospital and was managed with a course of dexamethasone and had a good outcome. However, post-discharge, the patient developed symptoms of productive cough, hemoptysis and shortness of breath. Evaluation of the patient revealed that the patient had developed a secondary bacterial infection with Methicillin-resistant Staphylococcus aureus (MRSA), resulting in MRSA pneumonia and empyema. The patient was started on appropriate antibiotics and underwent thoracocentesis followed by video-assisted thoracoscopic surgery (VATS) and decortication. MRSA infection resulted in severe septic shock, acute respiratory distress syndrome (ARDS) and multiorgan failure. Successful intensive care unit (ICU) management of the life-threatening complications resulted in the remarkable recovery of the patient.

Parallel Evolution of Linezolid Resistant Staphylococcus aureus in Patients with Cystic Fibrosis

Background

Linezolid is an antibiotic used to treat serious Staphylococcus aureus infections. Resistance to linezolid is considered rare but could emerge with repeated dosing. We recently reported widespread prescription of linezolid for a cohort of patients with cystic fibrosis (CF).

Objectives

The goals of this study were to determine the incidence of linezolid resistance in CF and identify molecular mechanisms for linezolid resistance.

Methods

We identified patients with S. aureus resistant to linezolid (MIC > 4) at the University of Iowa CF Center between 2008 and 2018. We obtained isolates from these patients and retested susceptibility to linezolid using broth microdilution. We used whole genome sequencing to perform phylogenetic analysis of linezolid resistant isolates and examine sequences for mutations or accessory genes that confer linezolid resistance.

Main Results

Between 2008 and 2018, 111 patients received linezolid and 4 of these patients cultured linezolid resistant S. aureus . We sequenced 11 resistant and 21 susceptible isolates from these 4 subjects. Phylogenetic analysis indicated that linezolid resistance developed in ST5 or ST105 backgrounds. Three individuals had linezolid resistant S. aureus with a G2576T mutation in 23S rRNA. One of these subjects additionally had a mutS - mutL - hypermutating S. aureus that produced 5 resistant isolates with multiple ribosomal subunit mutations. In one subject, the genetic basis for linezolid resistance was unclear.

Conclusions

Linezolid resistance evolved in 4 of 111 patients in this study. Linezolid resistance occurred by multiple genetic mechanisms. All resistant strains developed in ST5 or ST105 MRSA backgrounds.

Key Point

Linezolid resistance arises through multiple genetic mechanisms and could be facilitated by mutator phenotypes. Linezolid resistance was transient, possibly due to growth disadvantage.

Comparative In Vitro Activity of New Lipoglycopeptides and Vancomycin Against Ocular Staphylococci and Their Toxicity on the Human Corneal Epithelium

PURPOSE

The purpose of this study was to assess the potential of new lipoglycopeptides as novel topical therapies for improved treatment of recalcitrant ocular infections. We evaluated the in vitro antimicrobial activity of oritavancin, dalbavancin, and telavancin compared with vancomycin (VAN) against a large collection of ocular staphylococcal isolates and their cytotoxicity on human corneal epithelial cells (HCECs).

METHODS

Antimicrobial susceptibility testing was performed by broth microdilution against 223 Staphylococcus spp. clinical isolates. Time-kill kinetics were determined for methicillin-resistant strains of Staphylococcus aureus (MRSA) (n = 2) and Staphylococcus epidermidis (MRSE) (n = 1). In vitro cytotoxicity assays were performed with AlamarBlue and live/dead staining on HCECs.

RESULTS

All new lipoglycopeptides showed strong in vitro potency against ocular staphylococci, including multidrug-resistant MRSA strains, with dalbavancin showing a slightly higher potency overall [minimum inhibitory concentration (MIC) 90 0.06 μg/mL] compared with telavancin and oritavancin (MIC 90 0.12 μg/mL), whereas VAN had the lowest potency (MIC 90 2 μg/mL). Oritavancin exerted rapid bactericidal activity within 1 h for MRSA and 2 h for MRSE. All other drugs were bactericidal within 24 h. At a concentration commonly used for topical preparations (25 mg/mL), cytotoxicity was observed for VAN after 5 min of incubation, whereas reduction in HCEC viability was not seen for telavancin and was less affected by oritavancin and dalbavancin. Cytotoxicity at 25 mg/mL was seen for all drugs at 30 and 60 min but was significantly reduced or undetected for lower concentrations.

CONCLUSIONS

Our study demonstrates that new lipoglycopeptides have substantially better in vitro antimicrobial activity against ocular staphylococcal isolates compared with VAN, with a similar or improved toxicity profile on HCECs.

A Rare Case of Acute Cholecystitis Caused by Methicillin-Resistant Staphylococcus aureus (MRSA) in an Immunocompetent Person in the Absence of Bacteremia or Pre-Existing Conditions

Acute cholecystitis, typically caused by gallstone obstruction of the cystic duct, is often complicated by infection. Mostly observed in immunocompromised patients with bacteremia Methicillin-resistant Staphylococcus aureus (MRSA) is not typically associated with this ailment. Here, we present a unique case of acute cholecystitis caused by MRSA in an immunocompetent patient without bacteremia or underlying disease. A male patient aged 59 years was admitted complaining of severe abdominal pain and nausea. Subsequent investigation confirmed acute calculous cholecystitis and thereafter, the patient underwent laparoscopic cholecystectomy. Gallbladder fluid culture indicated elevated quantities of MRSA growths, and suitable antimicrobial therapy was given as part of the treatment process. This exceptional case underlines the significance of recognizing MRSA as a potential pathogen in severe acute cholecystitis cases, particularly those with severe symptoms. Rapid identification and usage of anti-MRSA antibiotics play a crucial role in managing MRSA-related situations. Healthcare providers need to bear in mind the possibility of cholecystitis associated with MRSA particularly when conventional risk factors are not present. Timely intervention is essential for favorable patient outcomes.

Cutaneous Necrosis of the Skin Secondary to Methicillin-Resistant Staphylococcus aureus (MRSA) and Bacteroides With Superimposed Herpes Simplex Virus Type II (HSV-II) in the Setting of Infective Endocarditis

Herpes simplex virus type II (HSV-II) with superimposed bacterial skin infection is an uncommon presentation of cutaneous necrosis in the setting of infective endocarditis. This case reflects a unique presentation of an immunosuppressed patient with infective endocarditis complicated by septic emboli and cutaneous skin lesions attributable to HSV-II and superimposed bacterial skin infection. The patient presented from an outside hospital with symptoms consistent with acute onset heart failure and skin lesions. Transthoracic and transesophageal echocardiography performed there demonstrated focal thickening of the anterior mitral valve leaflet with severe mitral regurgitation. The patient then underwent extensive infectious work-up and was put on broad-spectrum antibiotics. Further work-up demonstrated greater than three DUKE minor criteria and reiterated the focal thickening of the anterior leaflet of the mitral valve, making infective endocarditis the most likely etiology. Biopsies of the skin lesions were performed which stained positive for HSV-II and grew methicillin-resistant Staphylococcus aureus and Bacteroides fragilis. The cardiothoracic surgery service ultimately decided not to perform any surgical intervention to the mitral valve during her hospitalization as she was deemed to be too high of a risk due to her thrombocytopenia and significant comorbidities. She was later discharged in hemodynamically stable condition on long-term intravenous antibiotics with repeat echocardiography demonstrating significant reduction in the mitral regurgitation and the focal thickening of the anterior leaflet of the mitral valve.

Hiding in Plain Sight: Benefit of Abrasion and Laceration Swabs in Identification of Panton-Valentine Leucocidin (PVL)-Meticillin Resistant Staphylococcus aureus (MRSA) Colonisation in Military Personnel

Background Outbreaks of Panton-Valentine Leucocidin (PVL)-producing methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) are a recurrent challenge for the Royal Marines at the Commando Training Centre (CTCRM). The intensity of commando training, its impact on skin integrity, and persistent colonisation reservoirs within the training centre have thwarted attempts to prevent these outbreaks. Aim To present an outbreak of PVL-producing MRSA SSTIs at a military training centre, demonstrating the benefit of additional abrasion and laceration swabs on the identification of colonised personnel and showing the effectiveness of a 10-day decolonisation regime. Method Following the identification of the outbreak of PVL-producing MRSA, all 36 members of the Recruit Troop underwent nasal MRSA screening to identify MRSA carriers. The screening was repeated on day 16 after completing an enhanced 10-day decolonisation regime. A third screening was conducted on the 110th day after a second peak of infection was identified. Various infection control measures, such as enhanced cleaning, restriction of movement and adjustments to the military training serials, were introduced to prevent further spread through the training centre. Results In this outbreak, two-thirds (eighteen) of the Recruit Troop suffered MRSA-PVL skin infections requiring antibiotic therapy and three required hospital admission for surgical management of their abscesses. The outbreak lasted 130 days, with two spikes in infections 10 weeks apart. The outbreak was successfully confined to one troop. Conclusion With concerns about low identification rates of carriers using nasal screening for MRSA, in this outbreak, we improved the identification of asymptomatic carriage with the simple step of additional culture swabs for all cuts and abrasions. Improved identification of colonised recruits, along with an enhanced decolonisation regime and rigid infection control practices, prevented the further spread of the clone through the training centre. In a population with constant ongoing skin trauma, such as the military, contact sport athletes and iIV drug users, our results show that a culture of suitable abrasions/lacerations will improve the identification of MRSA colonisation compared with nasal swabs alone. Despite ongoing skin trauma and the logistical difficulties in delivering effective decolonisation during military training, decolonisation was successful in 79% of recruits after one decolonisation and 87% after the second 10-day decolonisation.

Risk Factors and Outcome Analysis of Gram-Positive Bacteremia in Critically Ill Patients

Introduction Bloodstream infection (BSI) is a common problem for patients in the intensive care unit (ICU). Nearly 60% of primary bloodstream infections are caused by Gram-positive cocci. Gram-positive bacteria gain access to the bloodstream through invasive procedures and various patient care equipment like catheters, intravenous lines, and mechanical ventilators. S. aureus is considered to be the major cause of septicemia. Knowledge of healthcare-associated infections and the antimicrobial susceptibility patterns of the isolates are crucial in guiding empirical treatment. Methods This prospective observational study was conducted in Medical ICU, Dayanand Medical College & Hospital, Ludhiana over a period of one year (December 2015 to November 2016). Patients whose blood cultures tested positive for Gram-positive bacteria were included in the study. This study was carried out to assess the implications and risk factors for nosocomial BSI and several factors, including the age of the patient, the severity of illness, the presence of catheters, and the microorganisms causing the BSI to independently predict mortality. Chief complaints and risk factors were evaluated. APACHE-II scores were calculated for all patients and outcomes were analyzed. Results In our study, the mean age of patients was 50.93±14.09 years. Central line insertion was found as the most common risk factor (58.7%). A statistically significant correlation was obtained between APACHE-II scores and the presence of risk factors i.e. central line insertion (p-value=0.010) and diabetes mellitus (p-value=0.003). The most common Gram-positive pathogen isolated by blood culture was methicillin-sensitive S. aureus (44.2%). For management, the majority of the patients were prescribed teicoplanin (58.7%). The 28-day overall mortality rate in our study was 52.9%. Conclusion We conclude that independent risk factors like diabetes mellitus, central line insertion, and acute pancreatitis in adult patients with Gram-positive bacteremia were associated with higher mortality. We have also concluded that the administration of early appropriate antibiotics improves patient outcomes.

Current molecular approach for diagnosis of MRSA: a meta-narrative review

Introduction:

Detection and diagnosis of methicillin-resistant Staphylococcus aureus (MRSA) are important in ensuring a correct and effective treatment, further reducing its spread. A wide range of molecular approaches has been used for the diagnosis of antimicrobial resistance (AMR) in MRSA. This review aims to study and appraise widely used molecular diagnostic methods for detecting MRSA.

Methods:

This meta-narrative review was performed by searching PubMed using the following search terms: (molecular diagnosis) AND (antimicrobial resistance) AND (methicillin-resistant Staphylococcus aureus). Studies using molecular diagnostic techniques for the detection of MRSA were included, while non-English language, duplicates and non-article studies were excluded. After reviewing the libraries and a further manual search, 20 studies were included in this article. RAMESES publication standard for narrative reviews was used for this synthesis.

Results:

A total of 20 full papers were reviewed and appraised in this synthesis, consisting of PCR technique (n = 7), deoxyribonucleic acid (DNA) Microarray (n = 1), DNA sequencing (n = 2), Xpert MRSA/SA BC assay (n = 2), matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) (n = 2), MLST (n = 4), SCCmec typing (n = 1) and GENECUBE (n = 1).

Discussion:

Different diagnostic methods used to diagnose MRSA have been studied in this review. This study concludes that PCR has been extensively used due to its higher sensitivity and cost-effectiveness in the past five years

A Case Report of Sepsis Post Cardiac Catheterization

Percutaneous coronary intervention (PCI) and cardiac catheterization are clean procedures done under aseptic precautions, but studies have shown transient bacteremia following the process, mostly involving Staphylococcus. This has many complications, from localized wounds at arterial access sites to endocarditis, mycotic aneurysm, and sepsis, and are associated with high mortality. These may require surgical intervention and prolonged antibiotic use. The risk of acquiring these infections is higher in femoral catheterization than in radial access. This risk also increases in patients with congestive cardiac failure, age 60 and above, and those with diabetes and obesity. Procedural hazards include multiple punctures and leaving the sheath for future access due to the needle tract's colonization. We present a case of sepsis presenting two days after PCI using single puncture radial access and a rapid downhill course.

Stability, Toxicity, and Antibacterial Potential of Gallic Acid-Loaded Graphene Oxide (GAGO) Against Methicillin-Resistant Staphylococcus aureus (MRSA) Strains

Background

The impetuous usage of antibiotics has led to the perpetual rise of methicillin-resistant Staphylococcus aureus (MRSA), which has garnered the interest of potential drug alternatives, including nanomaterials.

Purpose

The present study investigates the stability, toxicity, and antibacterial potential of gallic acid-loaded graphene oxide (GAGO) on several MRSA strains.

Methods

The stability of a synthesized and characterized GAGO was monitored in different physiological media. The toxicity profile of GAGO was evaluated in 3T3 murine fibroblast cells and the embryonic zebrafish model. The antibacterial activity of GAGO against MRSA, methicillin-susceptible S. aureus (MSSA), and community-acquired MRSA; with or without Panton-valentine leucocidin gene (MRSA-pvl+ and MRSA-pvl-) was investigated through disk diffusion, CFU counting method, time-kill experiment, and high-resolution transmission electron microscopy (HRTEM) observation.

Results

A stable GAGO nanocomposite has shown an improved toxicity profile in 3T3 murine fibroblast cells and zebrafish embryos, besides exhibiting normal ROS levels than graphene oxide (GO) and GA (gallic acid). The nanocomposite inhibited the growth of all bacterial strains employed. The effectiveness of the GAGO nanocomposite was comparable to cefoxitin (CFX), at ≥150 µg/mL in MRSA and MSSA. GAGO exhibited a significantly delayed response towards MRSA-pvl+ and MRSA-pvl-, with increased inhibition following 8 to 24 h of exposure, while comparable activity to native GA was only achieved at 24 h. Meanwhile, for MRSA and MSSA, GAGO had a comparable activity with native GA and GO as early as 2 h of exposure. HRTEM observation further reveals that GAGO-exposed cells were membrane compromised.

Conclusion

In summary, the present study indicates the antibacterial potential of GAGO against MRSA strains, but further study is warranted to understand the mechanism of action of GAGO and its resistance in MRSA strains.

Monitoring of microbiological dynamics in beach sand and seawater samples from recreational and non-recreational beaches over a two-year period

The frequencies of Escherichia coli, Staphylococcus aureus and Methicillin-resistant S. aureus (MRSA) and 'aerobic mesophilic bacteria' (AMB) counts in different seasons and marine sources were compared to understand the microbiological dynamics at beaches in N. Cyprus. Also, antibiotic resistance patterns were evaluated. The characterization and AMB enumeration studies were performed by conventional microbiological methods. AMB counts increased from winter to summer significantly (45.5*10⁴ CFU/mL to 2.5*10⁶ CFU/mL). Similarly, percentage detection frequencies of the bacteria were higher in summer compared to winter and were significant particularly for E. coli in both sand and seawater samples in 2019 and 2020 (p = 0.0181, p = 0.0142, p = 0.1257, p = 0.0446, respectively). However, a significant difference was not detected in percentage detection frequencies in terms of different sources or recreational status of beaches. The highest resistance percentages were detected against beta-lactam and lincosamides group of antibiotics. Results of the study signified that regular microbiological monitoring for beaches is essential.

1,3-Dioxane-Linked Novel Bacterial Topoisomerase Inhibitors: Expanding Structural Diversity and the Antibacterial Spectrum

Antibacterial resistance continues its devastation of available therapies. Novel bacterial topoisomerase inhibitors (NBTIs) offer one solution to this critical issue. Two series of amine NBTIs bearing tricyclic DNA-binding moieties as well as amide NBTIs with a bicyclic DNA-binding moiety were synthesized and evaluated against methicillin-resistant Staphylococcus aureus (MRSA). Additionally, these compounds and a series of bicyclic amine analogues displayed high activity against susceptible and drug-resistant Neisseria gonorrhoeae, expanding the spectrum of these dioxane-linked NBTIs.

Mechanistic Studies and In Vivo Efficacy of an Oxadiazole-Containing Antibiotic

Methicillin-resistant Staphylococcus aureus (MRSA) infections are still difficult to treat, despite the availability of many FDA-approved antibiotics. Thus, new compound scaffolds are still needed to treat MRSA. The oxadiazole-containing compound, HSGN-94, has been shown to reduce lipoteichoic acid (LTA) in S. aureus, but the mechanism that accounts for LTA biosynthesis inhibition remains uncharacterized. Herein, we report the elucidation of the mechanism by which HSGN-94 inhibits LTA biosynthesis via utilization of global proteomics, activity-based protein profiling, and lipid analysis via multiple reaction monitoring (MRM). Our data suggest that HSGN-94 inhibits LTA biosynthesis via direct binding to PgcA and downregulation of PgsA. We further show that HSGN-94 reduces the MRSA load in skin infection (mouse) and decreases pro-inflammatory cytokines in MRSA-infected wounds. Collectively, HSGN-94 merits further consideration as a potential drug for staphylococcal infections.

Pathogenicity and virulence of Staphylococcus aureus

Staphylococcus aureus is one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. This pathogen can cause a wide variety of diseases, ranging from moderately severe skin infections to fatal pneumonia and sepsis. Treatment of S. aureus infections is complicated by antibiotic resistance and a working vaccine is not available. There has been ongoing and increasing interest in the extraordinarily high number of toxins and other virulence determinants that S. aureus produces and how they impact disease. In this review, we will give an overview of how S. aureus initiates and maintains infection and discuss the main determinants involved. A more in-depth understanding of the function and contribution of S. aureus virulence determinants to S. aureus infection will enable us to develop anti-virulence strategies to counteract the lack of an anti-S. aureus vaccine and the ever-increasing shortage of working antibiotics against this important pathogen.

Distribution and antibiotic-resistance of different Staphylococcus species identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) isolated from the oral cavity

Background: The use of antibiotics in dentistry is associated with the emergence and spread of antibiotic-resistant microorganisms, including commensal staphylococci.

Methods: A total of 367 oral samples were collected, from which staphylococci were isolated and identified by using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). The antibiotic susceptibility of the isolates was determined and molecular characteristics for methicillin-resistant staphylococci was performed.

Results: A total of 103 coagulase-negative staphylococci (CoNS), among them S. warneri, S. haemolyticus, S. saprophyticus, S. pasteuri, S. epidermidis, S. hominis, S. xylosus, S. equorum, S. kloosii, S. succinus, S. cohnii, and S. simulans, were confirmed by MALDI-TOF. Resistance to most tested antibiotics was statistically higher in CoNS than in S. aureus isolates (P-value < 0.05). CoNS isolates showed high resistance to penicillin (S. saprophyticus 88.9%), erythromycin (S. haemolyticus 84.6%), fusidic acid (S. saprophyticus 77.8%), co-trimoxazole (S. epidermidis 71.4%), gentamicin (S. warneri 63.8%), and tetracycline (S. saprophyticus 55.6%). Multidrug resistance was largely observed, especially among S. haemolyticus and S. saprophyticus species. Methicillin-resistance in S. haemolyticus (38.5%), S. saprophyticus (22.2%) and S. aureus (13.5%) was associated with the presence of the mecA gene and SCCmec type IV or V.

Conclusion: Coagulase-negative staphylococci, especially S. haemolyticus and S. saprophyticus, seem to be a reservoir of methicillin resistance and multidrug resistance in the oral cavity.

Staphylococcus Aureus Bacteremia Due to Central Venous Catheter Infection: A Clinical Comparison of Infections Caused by Methicillin-Resistant and Methicillin-Susceptible Strains

Objectives: Staphylococcus aureus bacteremia has a mortality rate of 20-40% and is mainly caused by central venous catheter (CVC) infection. We aimed to investigate differences between patients with methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) bacteremia due to CVC infection.

Methods: This retrospective study, of data collected between August 2004 and March 2016 at a single Tokyo hospital, compared the clinical background characteristics, complications, and 60-day mortality rates with positive peripheral blood cultures and positive semiquantitative cultures. MRSA carrier is defined as those with a history of MRSA detection by skin, urine, or sputum culture.

Results: The median ages for the 17 MRSA and 19 MSSA patients were 72 and 55 years, respectively (P < 0.01). The occurrences of baseline disease (MRSA vs. MSSA) were 59% vs. 16% (P = 0.01), respectively, while those of complications, including septic shock, were 48% vs. 16% (P = 0.07), respectively. Catheter placement duration, time from fever onset to CVC removal, and time from fever onset to antimicrobial therapy initiation were similar in both groups. Sixty-day mortality rates were 35% and 5.3% (P = 0.04) in the MRSA and MSSA groups, respectively.

Conclusion: MRSA carriers and older patients were at higher risks of CVC infection than MSSA bacteremia patients. Patients with MRSA bacteremia had higher septic shock and 60-day mortality rates despite appropriate antimicrobial therapy.

Genetic variation of staphylococcal LukAB toxin determines receptor tropism

Staphylococcus aureus has evolved into diverse lineages, known as clonal complexes (CCs), which exhibit differences in the coding sequences of core virulence factors. Whether these alterations affect functionality is poorly understood. Here, we studied the highly polymorphic pore-forming toxin LukAB. We discovered that the LukAB toxin variants produced by S. aureus CC30 and CC45 kill human phagocytes regardless of whether CD11b, the previously established LukAB receptor, is present, and instead target the human hydrogen voltage-gated channel 1 (HVCN1). Biochemical studies identified the domain within human HVCN1 that drives LukAB species specificity, enabling the generation of humanized HVCN1 mice with enhanced susceptibility to CC30 LukAB and to bloodstream infection caused by CC30 S. aureus strains. Together, this work advances our understanding of an important S. aureus toxin and underscores the importance of considering genetic variation in characterizing virulence factors and understanding the tug of war between pathogens and the host.

Population pharmacokinetics and Monte Carlo simulation for dosage optimization of fosfomycin in the treatment of osteoarticular infections in patients without renal dysfunction

Background: Fosfomycin is gaining interest in the treatment of complex osteoarticular infections (OI) due to MDR pathogens.Objective: The aims were to conduct population pharmacokinetics of fosfomycin in a cohort of OI patients receiving 16g/daily by intermittent (II) or continuous infusion (CI), and to carry out Monte Carlo simulations for dosage optimization in the treatment of these infections.Methods: Patients underwent blood sampling on day 5 of therapy (2-3 serial samples). Population pharmacokinetics and Monte Carlo simulations were performed to define the probability of target attainment (PTA) of 70% T>MIC, and the cumulative fraction of response (CFR) against common OI pathogens with dosages of 8, 12, 16, and 20g/day administered by II, extended-infusion (EI) or CI.Results: Forty-eight patients were recruited. A two-compartment open model with infusion input and first-order elimination was developed. Estimated creatinine clearance (CL_CR) was included as covariate in the final model. Monte Carlo simulations showed that optimal PTAs and CFRs (≥90%) may be achieved in three different classes of renal function by administering a daily dosage of: 2g q6h by II against S. aureus, E. coli, ESBL-producing E. Coli and MRSA; 8g by CI against CoNS, K. pneumoniae and ESBL-producing K. pneumoniae; 12g by CI against P. aeruginosa, and 16g by CI against KPC-producing K. pneumoniae Conclusion: Our study provides a strong rationale for considering fosfomycin dosages of  8-16 g daily by CI in several clinical scenarios for OI patients. Feasibility of administration by CI in an elastomeric pump makes fosfomycin a candidate for OPAT programs.

Population pharmacokinetics of dalbavancin and dosing consideration for optimal treatment of adult patients with staphylococcal osteoarticular infections

Background: Dalbavancin is gaining interest in the treatment of complex osteoarticular (OA) infections.Objective: To conduct a population pharmacokinetic analysis of dalbavancin in a prospective cohort of adult patients with Gram-positive OA infections and to identify optimal dosing regimens for long term-treatment.Methods: Non-linear mixed-effects modelling was performed with Monolix. Monte Carlo simulations were performed with six dalbavancin regimens (1500mg at day 1; 1000mg at day 1 plus 500mg at day 8; 1500mg at day1 and 8; 1500mg at day1 and 8 plus 500, 1000 or 1500mg at day 36) to assess the PTA of three pharmacodynamic target of fAUC_24h/MIC against S. aureus (>27.1, 53.3 and 111.1). Cumulative fraction of response (CFR) was calculated against MIC distribution of both MRSA and MSSA as well. Desirable PTAs and CFRs were ≥90%.Results: Fifteen patients provided 120 plasma concentrations. Most (73.3%) had prosthetic joint infections. Clinical cure rate was 87%. A two-compartment model with linear elimination well described the data. No covariate was retained in the final model. Pharmacokinetic dalbavancin estimates were 0.106L/h for CL and 36.4L for V_ss The tested dosing regimens granted desirable CFRs against S. aureus at the most effective PK/PD target for a period ranging 3-to-9 weeks. Conclusion: Giving a two 1500mg dosing regimen of dalbavancin one week apart may ensure efficacy against both MSSA and MRSA up to 5 weeks in patients with OA infections. Clinical assessment at that time may allow for considering whether or not an additional dose should be administered for prolonging effective treatment.

Augmented Renal Clearance in a Case of Sepsis Leading to Vancomycin Failure Despite Increasing Dose As per the Estimated Glomerular Filtration Rate

Augmented renal clearance (ARC) is a unique clinical scenario observed in critically ill patients. We present a case of a 30-year-old male with sepsis secondary to methicillin-resistant Staphylococcus aureus (MRSA) bacteremia treated with vancomycin. ARC was observed in the patient with a maximum estimated glomerular filtration rate (eGFR) of 161.9 ml/min/1.73 m², and therapeutic drug monitoring was used to adjust the vancomycin dosage. Despite the maximal recommended dose of vancomycin, the therapeutic vancomycin level was not achieved, leading to treatment failure and subsequent mortality. Our case report suggests the necessity of other strategies, such as early dose adjustment of vancomycin based on vancomycin clearance and continuous vancomycin infusion, not merely conventional adjustment based on eGFR and vancomycin levels.

When Multidrug-Resistant Organism (MDRO)-Positive ICU Patient Isolation and Cohorting Is Not Feasible, What Comes Next?

Background The need for the implementation of an infection prevention strategy that included patient isolation and a cohorting procedure emerged in our ICU. Yet, isolation, as well as cohorting, were not feasible due to certain barriers associated with a high colonization pressure, open-plan ICU, inadequate bed separation, a limited number of isolation rooms, and nursing shortage. Despite these limitations, we tried to upgrade our ICU's infection prevention efforts by developing the "universal use of contact precautions approach" for infection prevention and control for all the patients with and without multidrug-resistant organisms (MDROs), cohorting, and single room isolation. The study aimed to evaluate the effectiveness of our approach. Methods A prospective cohort study using surveillance screening cultures for Methicillin-resistant Staphylococcus aureus (MRSA) and MDROs for a period of 18 weeks from October 1, 2018, to January 31, 2019. The main purpose of the approach was to isolate all patients (regardless of their MDRO/MRSA status) in their own bed space as if they were in an isolation room for the entire duration of their ICU hospitalization, in such a way as to prevent horizontal transmission of infection (infection acquisition) in our open-plan ICU.  Results Seventy-eight patients were admitted to our ICU for a total of 942 patient-days; a total of 432 swabs were collected during the study period. A total of 17 (21.8%) patients were admitted with a pre-existing infection while two (2.5%) patients acquired an infection during their ICU stay (one with Acinetobacter baumannii andone with Pseudomonas aeruginosa; 1.28 acquisition per 1000 patient-days). No transmission was documented for Klebsiella pneumoniae, Enterococcus faecalis, and Staphylococcus aureus. Conclusions Our MDRO acquisition rates suggested that the implementation of our infection control strategy potentially prevents the horizontal transmission of pathogens in an open-plan ICU, despite the high colonization pressure and the lack of isolation and cohorting procedures.

Antimicrobial prescribing for treatment of serious infections caused by Staphylococcus aureus and methicillin-resistant Staphylococcus aureus in pediatrics: an expert review

Introduction: Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), remains a significant pathogen in children. Despite evidence of decreasing prevalence, MRSA bacteremia has been closely associated with complications, including certain infections (i.e. musculoskeletal and endovascular) linked to increased treatment failures.Areas covered: This expert review summarized recent published literature on the role of treatment, dosing and administration of antibiotics used to combat serious S. aureus infections in children. The pertinent antibiotics presented were vancomycin, oxazolidinones, semi-synthetic glycopeptides, daptomycin, tigecycline, novel cephalosporins, fosfomycin and lefamulin. Vancomycin has been the most commonly used antibiotic in empiric therapy for serious MRSA infection, with new key recommendations emphasizing a different approach to dosing and therapeutic monitoring. For other antibiotics, data remain limited or clinical trials are underway.Expert opinion: MRSA remains a significant pathogen in the pediatric population. As numerous therapeutic agents are available, many agents have limited data on usage in pediatric patients. Future studies require pharmacokinetic, safety and efficacy studies in pediatric patients to ensure appropriate therapeutic treatment and outcomes. Phage therapy has been used to treat deep-seated MRSA infections and is an emerging investigational treatment option.

Prevalence of Methicillin-Resistant Staphylococcus aureus and Classical Enterotoxin Genes Among Sudanese Food Handlers

Food handlers who carry enterotoxin-producing Staphylococcus aureus could become potential reservoirs of Staphylococcal food poisoning. The study is a cross-sectional one aimed to determine the prevalence of methicillin-resistant S. aureus (MRSA) and staphylococcal enterotoxins from randomly selected food handlers in Al Jazirah state, Sudan. Culture swabs were collected from the hands and nasals of food handlers (2016-2018). Identification of S. aureus was done on the basis of conventional laboratory tests. All S. aureus isolates were screened for MRSA and staphylococcal enterotoxin (SE) genes by polymerase chain reaction. The S. aureus strains were isolated from 25% of the collected culture swabs of which 42% were confirmed as MRSA. The existence of one or more of enterotoxin genes was confirmed in 34.4% of the isolated S. aureus strains. The combined staphylococcal enterotoxin genes were found in 9.6% of the isolates. The SE genes among MRSA strains (61.5%) were found to be higher than methicillin-sensitive S. aureus strains (14.8%). The most frequent staphylococcal enterotoxin genes were SEA (19.4%) followed by the SEB (8.6%), SEC (4.3%), and SED (2.1%). The carriage rate of MRSA strains demonstrated a higher rate of staphylococcal enterotoxins genes than methicillin-sensitive S. aureus. There is an increasing prevalence of MRSA compared with the previous rates and staphylococcal enterotoxin genes among Sudanese food handlers, which is a serious problem for public health. 

Community-Associated Methicillin-Resistant Staphylococcus aureus: Case Report of Acute Sinusitis With Orbital Extension in a Pregnant Lady

Methicillin-resistant Staphylococcus aureus (MRSA) infections pose a significant burden on healthcare. Acute sinusitis can be one of its deadliest presentations as it can quickly lead to orbitocranial extension with complications including blindness, brain abscess and death. Previously believed to affect immunocompromised individuals only, community-associated MRSA is now known to affect healthy individuals too. The seriousness of MRSA infection increases manifold when the infection occurs in pregnant women who are immune modulated. We present a case of a 34-year-old pregnant lady who presented with a severe headache for two days. She had acute sinusitis that involved right orbit in less than 24 hours. She was promptly managed with intravenous antibiotics and drainage of abscess that revealed MRSA. Fortunately, the patient made a complete recovery. The purpose of this case report is to emphasize on keeping a high index of suspicion of MRSA for all soft tissue infections. Early recognition, proper evaluation and timely and appropriate treatment can prove lifesaving.

Resistance Profiles of Staphylococcus aureus and Immunological Status in Pregnant Women at Bafang, West Region of Cameroon: A Cross-Sectional Study

Background

Staphylococcus aureus, a facultative aero-anaerobic Gram-positive coccus typically considered normal flora in the human gastrointestinal tract, have increasingly become a major cause of healthcare-associated infections over the past decade. This study aimed to evaluate the changes in immune factors in pregnant women colonized by S. aureus in the town of Bafang, West Region of Cameroon.

Methods

A cross-sectional study was carried in antenatal care unit in various health center in Bafang. S. aureus were isolated in stools using specific bacterial culture media. Antimicrobial susceptibility test was carried out using disk diffusion method. Blood was used to measure CD3, CD4 and CD8 T-cell lymphocyte counts, white blood cell count, high sensitivity C-reactive protein (hs-CRP) and interleukin-6 measurement using flow cytometry, optical detection and the ELISA solid phase direct sandwich method, respectively.

Results

Out of the 169 patients studied, 76.30% patients were pregnant women and 23.70% were non-pregnant women. S. aureus were isolated in 70.41% participants that is, 78.15% in pregnant and 21.85% in non-pregnant women. The mean age was significantly higher in non-pregnant women (29.38 ± 7.685 years) compared to pregnant women (25.55 ± 5.521 years). CD4 T-cell (574.80 ± 165.94; 754.03 ± 162.28, p < 0.001), were significantly lower in pregnant than non-pregnant women respectively, contrary for CD8 T-cell (333.86 ± 233.04; 250.40 ± 227.75, p = 0.043). S. aureus were significantly more isolated in pregnant women with a CD4 T-cell count between 410 and 625 cells/µl (p < 0.001). S. aureus were more susceptible to imipenem (91.40%), (100%); ciprofloxacin (65.59%), (69.44%); amikacin (96.77%), (100%) and resistant to chloramphenicol (78.49%), doxycycline (64.52%) and cefotaxime (51.61%) in pregnant women. Staphylococcus aureus showed a significant increased multidrug resistant (MDR) and methicillin-resistant S. aureus (MRSA) phenotypes in pregnant compared to non-pregnant women (p < 0.05).

Conclusion

The present study revealed that, Staphylococcus aureus, including resistant phenotypes should be considered in pregnant women to improve their health care.

MRSA Septicemia With Septic Arthritis and Prostatic, Intraretinal, Periapical, and Lung Abscesses

INTRODUCTION

Methicillin-resistant staphylococcus aureus (MRSA) bacteremia is a life-threatening illness and a major global health care problem. It can cause metastatic and complicated infections.

CASE PRESENTATION

A 58-year-old man with uncontrolled type 2 diabetes mellitus presented with altered mental status after a fall. He was found to have a hip fracture, diabetic ketoacidosis, and MRSA bacteremia. This was complicated by septic knee arthritis, prostatic abscess, intraretinal abscess, periapical abscesses, and pulmonary abscesses. He was treated with intravenous vancomycin and oral linezolid and eventually recovered.

DISCUSSION

Severe metastatic MRSA infection was likely due, in part, to the patient's uncontrolled diabetes, as he has no underlying immunodeficiency and was HIV negative. Prostatic abscesses are a relatively rare occurrence that typically develop in immunocompromised patients.

CONCLUSION

This case is an interesting confluence of sequelae of MRSA bacteremia and reinforces the necessity for clinicians to be diligent when evaluating a patient with a suspected prostatic abscess.

A Rare Case of Prostatic and Bilateral Renal Abscesses Caused by Community-acquired Methicillin-resistant Staphylococcus aureus Infection

Gram-negative bacilli are usually implicated in the formation of prostatic abscesses (PA) which is a rare complication of prostatitis. However, PA methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a substantial cause of PA in recent years. Predisposing factors for MRSA prostatitis include immunocompromised states such as human immunodeficiency virus (HIV), uncontrolled diabetes, intravenous drug use (IVDU), urethral instrumentation, bladder outlet obstruction, preexisting prostatic disease, recent prostatic procedure, and chronic dialysis among others. MRSA PA should be promptly diagnosed and appropriately treated as delay in diagnosis can be detrimental. We present a case of a patient with a remote history of IVDU who developed simultaneous bilateral renal and PA caused by MRSA in the absence of MRSA bacteremia. Since our patient did not have the traditional risk factors for MRSA infection, we can argue that he was infected by the community-acquired strains of MRSA.

Minimum Inhibitory Concentrations of Vancomycin and Daptomycin Against Methicillin-resistant Staphylococcus Aureus Isolated from Various Clinical Specimens: A Study from South India

Background Staphylococci are Gram-positive cocci arranged in clusters. They are colonized in humans and animals. Also, Staphylococcus aureus (S. aureus) is frequently associated with various superficial to deep-seated infections in humans. Due to the potential for easy transmission, Staphylococci are associated with both hospital-acquired and community-associated infections. Strains of S. aureus resistant to methicillin (MRSA) pose treatment challenges. In such cases, vancomycin is the treatment of choice. Due to the indiscriminate use of vancomycin, recently, we are seeing the emergence of vancomycin-intermediate sensitive S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA). The present study aims to evaluate the minimum inhibitory concentrations (MICs) of vancomycin and daptomycin among MRSA strains isolated from human clinical specimens Methods The study included 115 MRSA isolates collected over 26 months from July 2010 to September 2012. The strains were isolated from pus, urine, wound swabs, catheters, blood, and sputum. The bacteria were acquired from different inpatient and outpatient departments of Prathima Institute of Medical Sciences, Karimnagar, Telangana, India. Kirby-Bauer disk diffusion method using cefoxitin was used to confirm the MRSA isolates. The agar dilution and the Epsilometer method (E-test) were used to test the MICs of MRSA isolates against vancomycin and daptomycin, respectively, by the standard procedures recommended by the clinical laboratory standards institute (CLSI). Results Of the 115 S. aureus isolates, seven (6.08%) strains were resistant to vancomycin (VRSA) and 53 (46.08%) were found to be VISA using the new CLSI breakpoints. The MIC of the daptomycin was found to be ≤1 µg/ml for all the MRSA isolates. Conclusion The study results depicted an increasing trend in the vancomycin MICs among the MRSA isolates. Several tested strains show MICs in the intermediate sensitive range (VISA). The daptomycin was effective against all the MRSA isolates.

Infectious Diseases: The Role of the Healthcare Professional

For the healthcare professional dealing with infections presents two main problems. First, managing detainees or police personnel who have contracted a disease and may be infectious or unwell, and second, handling complainants of assault, including police officers, who have potentially been exposed to an infectious disease. This chapter addresses some general principles of infection control and safety in the working environment and then goes on to discuss some infections that may be encountered in police custody and how they can best be managed.

Impact of a Pharmacist-driven Methicillin-resistant Staphylococcus aureus Polymerase Chain Reaction Nasal Swab Protocol on the De-escalation of Empiric Vancomycin in Patients with Pneumonia in a Rural Healthcare Setting

Introduction

Pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) carries a high rate of morbidity and mortality. Many clinicians empirically treat those at risk of developing MRSA pneumonia with vancomycin. Several studies have identified a high negative predictive value of the MRSA polymerase chain reaction (PCR) nasal swab test in lower respiratory tract infections, suggesting it can be used to guide the de-escalation of empiric anti-MRSA therapy.

Objective

To evaluate the impact of a pharmacist-driven MRSA PCR nasal swab protocol on the de-escalation of empiric vancomycin in patients with pneumonia in a rural healthcare setting. Secondarily, to assess the rate of hospital length of stay, the rate of vancomycin-associated acute kidney injury, and in-hospital mortality after pharmacist-driven de-escalation of empiric vancomycin in patients with pneumonia. 

Methods

A retrospective, single-center, pre-post cohort study was conducted in patients after the implementation of a pharmacist-driven protocol allowing pharmacists to obtain nasal swabs and PCR testing for MRSA in those on empiric vancomycin therapy for suspected MRSA pneumonia. Based on negative test results, pharmacists recommended a de-escalation of empiric vancomycin to the physician. Patients were included if they were adults at least 18 years of age, had a physician diagnosis of suspected or confirmed pneumonia, and initiated on at least one dose of intravenous vancomycin within 48 hours of admission.

Results

A total of 79 patients were identified for inclusion in the pre-protocol group (n=32) or post-protocol group (n= 47). The mean duration of vancomycin therapy in the pre-protocol group was 3.1 days as compared to 1.7 days in the post-protocol group for a 1.4 days reduction (p=0.044). There was no significant impact on the number of vancomycin cases de-escalated within 24 hours (p=0.14) but there was a significant reduction at 48 hours (p=0.01). Protocol implementation was associated with a reduction in the average length of hospitalization (8 versus 5.20 days, p=0.006). Neither group had a vancomycin-associated acute kidney injury or in-hospital mortality.

Conclusion

Among patients with suspected MRSA pneumonia, a pharmacist-driven MRSA PCR nasal swab protocol resulted in a significant reduction of empiric vancomycin duration of therapy without an adverse impact on clinical outcomes in a rural healthcare setting.

A Longitudinal Study of S. aureus Infection in a National Cohort of Surgical Patients

BACKGROUND

Postoperative infections are a common and often preventable complication of surgery. S. aureus is a prevalent organism cultured in these infections and is associated with morbidity, mortality, and increased healthcare utilization. However, the long-term burden of S. aureus infection in surgical patients is not well studied. The purpose of this retrospective observational study is to assess the incidence, time trend, and burden of S. aureus infection up to 1 year after surgery.

METHODS

We obtained manually-reviewed data from the VA Surgical Quality Improvement Program (VASQIP) to identify surgeries in all major specialties. These were combined with laboratory microbiology and pharmacy data to identify pneumonia and infections of the urinary tract, surgical site, and blood.

RESULTS

In the study population of 559,550 patients, S. aureus incidence decreased each year, from 2.1% in 2008 to 1.1% in 2015. Among these, incidence of methicillin-resistant S. aureus (MRSA) infection decreased from 0.7% to 0.4%, and methicillin-susceptible S. aureus (MSSA) decreased from 1.4% to 0.7%. S. aureus infection was associated with increased length of stay, ED utilization, inpatient admissions, as well as a 4-fold increase in mortality.

CONCLUSIONS

This is one of the largest studies describing the long-term incidence of S. aureus in the surgical population of a national integrated healthcare system. We conclude that the burden of S. aureus infection extends well beyond the conventional 30-day postoperative window, and late infection should be included in assessing the effects of interventions.

Trimethoprim-sulfamethoxazole Induced Pancytopenia: A Common Occurrence but A Rare Diagnosis

Trimethoprim-sulfamethoxazole (TMP-SMX) is a bacteriostatic antimicrobial medication used for the treatment of a variety of infections and has many reported skin and hematologic side effects. Due to the easy availability and cost effectiveness, TMP-SMX is one of the medications commonly used for treatment of skin and soft tissue in patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. One of the rare hematologic manifestations of TMP-SMX is pancytopenia, which is a reduction in all cell lines. In this case report, we are documenting a case of pancytopenia due to severe drug reaction to TMP-SMX in a 70-year-old female after two weeks of medication use. Upon initial stabilization she underwent a thorough workup and was subsequently diagnosed with severe drug-induced pancytopenia. Detailed history, early diagnosis, prompt discontinuation of the offending medication along with supportive care remain the mainstay of treatment in the management of TMP-SMX induced pancytopenia.

Purpura in the Emergency Room: Two Cases of Sepsis with Cutaneous Manifestations

Purpura fulminans is a seldom seen manifestation of sepsis in the emergency department (ED). The morbidity and mortality of sepsis have been widely studied and reported; the hallmark of treatment is early recognition and intervention. In extreme cases, sepsis can cause widespread activation of the coagulation cascade further complicating the treatment and recovery from the causative pathogen. We report two cases and their differing outcomes after presentation to the ED with similar dermatologic findings on initial physical exam.

Ceftaroline Fosamil as an Alternative for a Severe Methicillin-resistant Staphylococcus aureus Infection: A Case Report

Bacteremia secondary to methicillin-resistant Staphylococcus aureus (MRSA) is a dreaded medical condition that is not only associated with a significant medical cost but also carries high morbidity and mortality. The poor clinical outcomes seen in MRSA patients and the nephrotoxic effects of high-doses of vancomycin are challenging its current status as the first-line treatment for MRSA. Fortunately, vancomycin-intermediate-staphylococcus aureus (VISA) and vancomycin-resistant-staphylococcus aureus (VRSA) are not common in the United States. However, MRSA still presents different treatment challenges. Elevated vancomycin minimum inhibitory concentrations (MICs) commonly result in decreased efficacy and an increased probability of treatment failure, prompting the use of alternative agents. Although daptomycin is an alternative, adverse effects (i.e., elevations in serum creatine phosphokinase (CPK), drug-induced myopathy, peripheral neuropathy, and eosinophilic pneumonia) may limit its use in some patients. In the search for a suitable replacement for vancomycin, great promise has been shown by anti-MRSA cephalosporins.

We present a case of MRSA bacteremia and endocarditis requiring a different approach to treatment as compared to traditional treatment with vancomycin alone. This case report describes the successful treatment of MRSA bacteremia with ceftaroline fosamil in a patient who responded poorly to conventional therapy, specifically vancomycin, due to an elevated MIC (2 µg/mL).

Airborne MRSA and Total Staphylococcus aureus as Associated With Particles of Different Sizes on Pig Farms

Airborne methicillin-resistant Staphylococcus aureus (MRSA) have previously been found on pig farms, which may lead to nasal deposition of MRSA in humans via inhalation. The anterior nares are the main niche for S. aureus, and S. aureus can cause, e.g. wound infection and pneumonia. The aim of this study was to acquire knowledge about the potential deposition of airborne MRSA, specifically, and of total S. aureus (including both methicillin-sensitive S. aureus and MRSA, in the following called S. aureus) in the different parts of the airways during occupancy on pig farms. Measurements of airborne MRSA and S. aureus were performed on four pig farms using a six and a three-stage sampler during different work tasks, such as high-pressure cleaning and everyday inspection. MRSA were quantified using MRSA-selective agar, and S. aureus were quantified using Staphylococcus selective agar. The identity of the bacteria were confirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The geometric mean (GM) concentrations of MRSA and S. aureus were 447 cfu/m3 air and 1.8 × 103 cfu/m3 air, respectively. The highest concentrations of MRSA and S. aureus were found among pigs in a weaner stable and during high-pressure cleaning of an empty stable, respectively. The lowest concentrations of MRSA and S. aureus were found in a stable with sick pigs and in feed-storages, respectively. Most MRSA and S. aureus were associated with particles between 7 and 12 µm. On average, the particle size fractions potentially depositing in the upper airways constituted 70%, in the primary and secondary bronchi 22%, and in the terminal bronchi and alveoli 8% of the inhalable MRSA and S. aureus concentration. Across the sampled areas, the geometric mean diameter (Dg) of particles with MRSA and S. aureus were 7.2 and 6.4 µm, respectively, and no significant difference was found between these Dgs. The Dg of the airborne particles with the studied bacterium was significantly associated with the different locations on the farms. The largest Dgs were found in the air samples from the aisles and on the fence to the pens, while the smallest Dgs were found in samples from the pens among the pigs and in samples taken at greater distances from the pigs: in the hallway, feed-storage, and entry room. In conclusion, airborne MRSA and S. aureus were found in sample fractions potentially depositing in all six parts of the airways. However, the majority was found to potentially deposit in the upper airways. The concentration of airborne MRSA and S. aureus and MRSA, as well as the fraction potentially depositing in the different parts of the airways, depended on the specific work task being performed and the location on the farm.