Methicillin-resistant Staphylococcal Aureus Research Articles

Microbiological profile of abscesses of different body sites in a tertiary care hospital – the silent killer

Background: Abscess, an infection with viable infecting organisms and polymorphonuclear cells, contained within a fibrous capsule, limiting the infection, and preventing its further spread. It may be monomicrobial or polymicrobial. Aims and Objectives: The aims of the study were to determine microbiological profile of abscesses of different body sites and associated complications. Materials and Methods: An observational study was conducted in our department with 35 pus samples from abscesses of different body sites between August 2022 and December 2022. Gram stain, Z-N stain, fungal stain, aerobic, anaerobic, and fungal culture were performed. Statistical analysis was done by statistical tool R. Results: Out of 35 samples-limb, liver,paraspinal, psoas, appendicular, breast, perineal, ear, brain and lung abscesses were 11,4,2,3,1,7,2,2,2,1 respectively. Most common organisms from limb,ear,paraspinal and breast abscesses was MRSA (Methicillin resistant Staphylococcal aureus). Also most common organisms were – Escherichia coli from liver abscess, Enterobacteriaceae and Pseudomonas aeruginosa from psoas and appendicular abscess, Enterobacter aerogenes from perineal, Escherichia coli and Actinomyces species from brain and Candida auris from lung abcesses. No growth were also found in few samples. Their susceptibility testing showed-MRSA strains susceptible to both Vancomycin and Linezolid, gram negative bacteria were susceptible to Cephalosporins, Piperacillin-tazobactam, Carbapenems, polymixins, etc. C.auris was resistant to all antifungals. Their blood samples were also collected - ten patients showed fever with bacteremia and one with candidemia . They were treated with systemic antimicrobials along with drainage and/or surgical resection. Conclusion: Abscesses must be suspected in cases with non-resolving fever with/without septicemia and treated promptly with appropriate antimicrobials based on susceptibility report and with drainage and/or surgical resection.

S1835 Silent Hemoperitoneum and MRSA Bacterascites: An Unusual Presentation of Gallbladder Perforation

Introduction: Gallbladder perforation (GBP) is an uncommon, life-threatening event, most often seen as a complication of acute cholecystitis. Occurrence of GBP in the absence of cholecystitis is exceedingly rare, but may occur in those with cholelithiasis. We report a case of spontaneous GBP without cholecystitis presenting as painless hemoperitoneum and methicillin-resistant Staphylococcal aureus (MRSA) bacterascites in a patient with decompensated cirrhosis. Case Description/Methods: A 63 year old female with past history of NASH cirrhosis (MELD 27, Child-Pugh C), esophageal varices, and ascites requiring weekly therapeutic paracentesis presented with encephalopathy. A paracentesis on admission was negative for spontaneous bacterial peritonitis by cell count and culture. CT imaging on admission revealed a partial small bowel obstruction (pSBO) and cholelithiasis with an otherwise normal gallbladder and biliary tree. The pSBO resolved with conservative management. One week into the hospitalization, her ascites worsened. A second paracentesis showed 253,290 RBC/mm3, with a corrected ANC of -54 cells/mm3. A 3 gram serum hemoglobin drop was also noted. A repeat abdominal CT scan showed a non-inflamed gallbladder with her known gallstones now layering in the pelvis, suggestive of GBP (Figure). She was initially started on piperacillin-tazobactam, but her ascitic fluid culture later grew MRSA. Based on her surgical risk and overall clinical stability, she was managed non-operatively. She was transitioned to indefinite therapy with amoxicillin-clavulanate and doxycycline, and later discharged home. Discussion: Most GBPs are due to severe inflammation or trauma. Risk factors for spontaneous GBP include cholelithiasis, congenital obstruction, and anticoagulant therapy. Although rare, patients with cirrhosis may have a higher risk for GBP due to venous congestion from portal hypertension and their propensity for cholelithiasis. Her MRSA bacterascites may have been from iatrogenic seeding during the first paracentesis, but the timeline to discovery raised concerns that it originated from the GBP. MRSA is rarely a biliary pathogen, but may result from bacteremia that seeds the gallbladder. Regardless, the patient began indefinite antibiotic therapy, as her gallstones posed as persistent nidi for infection. This case highlights the rare possibility of silent GBP as a cause for worsening ascites, as well as the therapeutic dilemma of retained peritoneal gallstones in a poor surgical candidate.Figure 1.: Gallstones residing in intact gallbladder on left, compared to subsequent scan on the right demonstrating gallstones in patient's pelvis.

English

BACKGROUND Gangrene refers to the dead or dying body tissue (s) that occurs because the local blood supply to the tissue is either lost or is inadequate to keep the tissue alive. Foot gangrene is becoming a major concern which changes the quality of life, and also the social and economic point of view. We wanted to study the clinical profile of foot gangrene, determine the most common aetiology, distribution of age and sex, presentation, associated risk factors, commonest organisms involved, ways to find and manage the complications, and study the outcomes of foot gangrene in a rural medical college. METHODS Clinical profiles of all 50 patients with foot gangrene were studied as a prospective observational study in a rural medical college from October 2018 to October 2020. All cases were evaluated by history, clinical examination, investigations, management and follow up. RESULTS Our study involved 50 patients; youngest patient was 33 years and oldest was 70 years. Majority of patients with foot gangrene were in the age group of 41 - 50 years, (22 cases) and highest number were males, (37 cases). Diabetes mellitus is the commonest aetiology accounting for 30 cases and commonest risk factor that confounds the disease process is smoking (17 cases). The commonest presentation was blackish discoloration of toe (s) along with cellulitis and ulceration (30 cases). The commonest organism isolated from culture is methicillin resistant Staphylococcal aureus (MRSA) (13 cases). Majority of the patients underwent Ray’s amputation (16 cases) in our study and majority had no post-operative wound complication (28 cases) within the minimum follow up period of 6 months. CONCLUSIONS We have therefore attempted in our study, to analyse the gangrene of the foot since diabetic cases and trauma cases are more in the rural setup and treatment of these gangrene cases is a challenging task as well. KEY WORDS Foot Gangrene, Amputation, Diabetes Mellitus

289 Reduction of Hospital-Acquired Methicillin Resistant Staphylococcal Aureus Bacteremia in a High Volume Adult Burn Center

289 Reduction of Hospital-Acquired Methicillin Resistant Staphylococcal Aureus Bacteremia in a High Volume Adult Burn Center

The Relationship Between Prevalence of Antibiotics Resistance and Virulence Factors Genes of MRSA and MSSA Strains Isolated from Clinical Samples, West Iran.

We sought to evaluate the relationship between the prevalence of antibiotics resistance and virulence factors genes in methicillin-resistant Staphylococcal aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains from clinical samples taken in west Iran. We performed a cross-sectional study using 100 MRSA and 100 MSSA samples isolated from clinical specimens. We used biochemical methods to identify the isolates, which were confirmed by the polymerase chain reaction (PCR) assay. Antibiotic susceptibility testing was performed using disk diffusion. PCR detected the presence of virulence factors, including enterotoxin genes, toxic shock syndrome toxin-1 (TSST-1), and exfoliative toxin. The majority of MRSA isolates exhibited a high level of resistance to common antibiotics and susceptible to vancomycin, while most MSSA isolates were also resistant to erythromycin and ciprofloxacin. The prevalence of Staphylococcal enterotoxins (SEs) were reported 147 (73.5%). Among 100 MRSA samples, 92 (92.0%) harbored SAg genes. The most frequent toxin gene was sea (45.0%) followed by sec (39.0%). Among 100 MSSA isolates, 89 (89.0%) harbored SAg genes and the most prevalent genes were sea (42.0%), sek (38.0%), sec (35.0%,), and TSST-1 (10.0%). The prevalence of TSST-1 and exfoliative toxin genes in MRSA samples were 12 (12.0%). The association of SAg genes with MRSA and MSSA isolates showed a high prevalence of enterotoxin seq, seg, and sei in MRSA than MSSA with a statistically significant difference (p < 0.050). The prevalence of MRSA and the association of pathogenic agents with antibiotics resistance genes can lead to the emergence of strains with higher pathogenicity and less susceptibility.

The effect of combined pulsed wave low-level laser therapy and mesenchymal stem cell-conditioned medium on the healing of an infected wound with methicillin-resistant Staphylococcal aureus in diabetic rats.

This study aims to investigate the combined effects of Pulsed wave low-level laser therapy (PW LLLT) and human bone marrow mesenchymal stem cell-conditioned medium (hBM-MSC-CM) on the microbial flora and tensiometrical properties of an infected wound model with methicillin-resistant staphylococcal aureus (MRSA) in an experimental model for Type 1 diabetes mellitus (TIDM). TIDM was induced in rats by streptozotocin (STZ). One full-thickness excision was made on the backs of the rats. Next, the rats were divided into the following groups: Group 1 was the control (placebo) group; Group 2 received hBM-MSCs-CM four times; Group 3 were laser PWLLLT (890 nm, 80 Hz, 0.2 J/cm2 ); and Group 4 received hBM-MSCs-CM +LASER. Wounds were infected with MRSA. Microbiological examinations were performed on days 4, 7, and 15. Tensiometerical examinations were carried out on the 15th day. One-way analysis of variance showed that laser and CM alone and/or in combination significantly increases the tensiomerical properties of the repaired wounds compared with control wounds. A combination of PW laser and CM was statistically more effective than other treated groups. Two-way analysis of variance showed that laser and CM alone and/or in combination significantly decreases the colony-forming units (CFUs) compared with the control group. The application of hBM-MSC-CM and PWlaser alone and/or together significantly accelerates the wound-healing process in MRSA-infected cutaneous wounds in TI DM in rats. Additionally, a combined application of hBM-MSC-CM and PWlaser demonstrates a synergistic effect on the wound-healing process in MRSA-infected cutaneous wounds in Type I DM rats.

Factors Affecting Staphylococcus aureus Colonization of the Nasopharynx in the First 6 Months of Life

Staphylococcal aureus (SA) colonization in early infancy is common, but the pattern and factors affecting its acquisition and persistence in the first few months of life are not well studied. The aim is to study the rate of SA nasopharyngeal (NP) colonization at monthly intervals in the first 6 months of life and its association with environmental and host factors and other pathogenic NP bacteria. Data from a prospective study were analyzed on bacterial cultures of 1765 NP swabs from 367 infants who were followed from birth to 6 months of age. Demographic, breastfeeding, cigarette smoke exposure and day care attendance data were collected at each monthly visit. The rate of infants colonized with SA was highest at age 1 month (25%) and declined to lowest rate by age 6 months (12%). The proportion of SA strains that was methicillin-resistant SA was also highest at age 1 month and declined rapidly by age 4 months (18% vs. 6%, P = 0.05). Colonization with Streptococcus pneumoniae (SP), nontypeable Haemophilus influenzae (NTHI) and Moraxella catarrhalis (MC) increased at different rates up to age 6 months. Univariate analysis showed that SA colonization rate was significantly lower with increasing age, black race, day care attendance, and colonization with NTHI, MC and SP (P < 0.05). Multivariate analysis showed that this effect was independently associated only with increasing age and MC colonization (P < 0.05). Furthermore, the time to first acquisition of SA from one month of age onwards was significantly associated with day care attendance, and NTHI and MC colonization. None of the infants colonized with SA developed SA infections through age 6 months. SA colonization of NP begins very early in life and declines quickly. Methicillin-resistant SA has lower ability to maintain prolonged colonization status than methicillin-susceptible strains in the first 6 months of life. As the NP is colonized with other respiratory bacterial pathogens, the colonization with SA declines; however, this effect is stronger with Gram-negative bacteria, such as NTHI and MC.

Successful Treatment of Intravenous Immunoglobulins in a Patient with Intractable Epidermolysis Bullosa Acquisita with Autoantibodies to Type VII Collagen and Laminin Alpha-3

Epidermolysis bullosa acquisita (EBA) is a blistering disease caused by autoantibodies to type VII collagen, a major component of anchoring fibrils at the dermal-epidermal junction. Here, we report a case of inflammatory EBA with a unique antibody prolife showing reactivity to laminin alpha-3 as well as type VII collagen. The patient’s cutaneous lesions were refractory to dapsone, prednisolone, betamethasone, and double filtration plasmapheresis, which led to a catheter-mediated methicillin-resistant staphylococcal aureus (MRSA) sepsis. Intravenous immunoglobulins (IVIG) initially used to resolve MRSA sepsis improved the pruritus and skin manifestations of EBA, and clinical remission of EBA was achieved after only two cycles of IVIG. The mechanism for the concurrence of antibodies to type VII collagen and laminin alpha-3 and the potential mode of action of IVIG in EBA are discussed.

Arteriovenous dialysis access-associated transvenous pacemaker infection

Pacemaker (PM), implantable cardioverter defibrillator and cardiac resynchronization therapy devices also provide support to chronic hemodialysis patients with cardiac rhythm abnormalities. However, these devices can get infected. In general, device infection is either primary or metastatic spread from a distant source. Arteriovenous grafts are commonly used to provide dialysis therapy. Compared to a fistula an arteriovenous graft runs a higher risk of infection. In this analysis, we report 2 chronic hemodialysis patients who have been successfully receiving dialysis through an arteriovenous graft for approximately 2 years. Both had had a PM device for about the same duration. Access infection necessitated surgical removal of the arteriovenous graft in these patients. However, due to bacteremia (methicillin-resistant Staphylococcal aureus (MRSA)), infection spread to involve the transvenous PM leads in both patients. In 1 patient the infection also involved the PM pocket. Lead and wound culture confirmed MRSA in both patients. PM device and leads were removed in both patients. After the resolution of bacteremia, both patients received an epicardial pacemaker. None of the patients had valvular endocarditis. While dialysis was provided with a catheter, an arteriovenous fistula was planned. In conclusion, contamination of the transvenous PM device can occur due to hematogenous spread of infection from an infected arteriovenous graft. Epicardial instead of a transvenous PM might be the better option for such patients to provide long-term cardiac rhythm support.

Concomitant methicillin‐resistant Staphylococcus aureus pericaditis, Cryptococcus neoformans pneumonia and invasive cytomegalovirus pneumonitis in a lupus patient with rare homozygous structural mutant variant at codon 54 of mannose binding lectin gene

AbstractMannose‐binding lectin (MBL) is a mediator of innate immunity. Individuals with exon 1 structural mutant genotypes are associated with unusual and recurrent infections. We describe a lupus patient who had life‐threatening, concomitant infections – methicillin‐resistant staphylococcal aureus (MRSA) pericarditis with tamponade, cryptococcal pneumonia and cytomegalovirus (CMV) pneumonitis. Tests were negative for complements or immunoglobulins deficiencies. There was no human immunodeficiency virus (HIV) infection. She has a homozygous structural mutant variant at codon 54 of the MBL gene. We surmised the severe multiple infections are related to this rare mutant variant, and may be triggered off by corticosteroid therapy.

Necrotizing Staphylococcal Pneumonia in a Neonate

Hospitalized neonates are commonly colonized soon after birth with Staphylococcus aureus. The majority of neonates do not develop infectious sequelae; however, premature neonates appear to be more susceptible to serious infections, such as pneumonia. We report a case of an extremely low birth weight infant who developed necrotizing pneumonia due to methicillin-resistant Staphylococcal aureus (MRSA). The MRSA isolate from this neonate is identical to the strains that have been causing primarily community-associated skin and soft tissue infections. The severe course of this patient may be attributed to the presence of the Panton-Valentine leukocidin gene, a well-known virulence factor leading to soft tissue and pulmonary infections.