Community-acquired Staphylococcal Infections Research Articles

Community-acquired and healthcare-associated Staphylococcus aureus infections in a pediatric hospital in southern Brazil over 8 years: how common is MRSA?

Both healthcare-associated and community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are relevant in children. The objective of our study was to evaluate their impact in a pediatric hospital in southern Brazil. Data from patients under 18 years of age with S. aureus infections between January 2013 and December 2020 were retrospectively analyzed. Data were collected regarding infection site, infection type (community-acquired or healthcare-associated), susceptibility to oxacillin [methicillin-susceptible S. aureus (MSSA) or MRSA] and other antimicrobials. We analyzed the evolution of the susceptibility rates for the isolates over this period. A total of 563 patients were included, among whom the prevalences of community- and hospital-acquired MRSA infections were 46.1% and 8.1%, respectively. No significant change occurred in these prevalences over the study period. In community-acquired infections, MSSA was significantly more associated with osteoarticular infections and MRSA was more associated with respiratory and intra-abdominal infections. In healthcare-associated infections, there was an association between MSSA and primary bloodstream infections and between MRSA, skin/soft tissue infections, and respiratory infections. Community-acquired MRSA were highly susceptible to trimethoprim-sulfamethoxazole (96.1%), clindamycin (88.4%), and doxycycline (99.0%). Our study draws attention to the high rates of MRSA in community-acquired staphylococcal infections in this population, indicating a need to review initial protocols for severe staphylococcal infections according to local epidemiology.

PM2.5-associated bacteria in ambient air: Is PM2.5 exposure associated with the acquisition of community-acquired staphylococcal infections?

Particulate matter (PM), a major component of air pollution, is an important carrier medium of various chemical and microbial compounds. Air pollution due to PM could increase the level of bacteria and associated adverse health effects. Staphylococci as important opportunistic pathogens that cause hospital- and community-acquired infections may transmit through air. This study aimed to obtain knowledge about the concentration of airborne bacteria as well as staphylococci associated with particulate matter with a diameter of less than 2.5 micrometers (PM2.5) in ambient air. The impact of meteorological factors including ultraviolet (UV) index, wind speed, temperature, and moisture on microbial concentrations was also investigated. Quartz filters were used to collect PM2.5 and associated bacteria in ambient air of a semiarid area. Airborne bacteria were quantified by culture method and Staphylococcus species identified by molecular methods. The mean (SD) concentration of PM2.5 and airborne bacteria was 64.83 (24.87) µg/m3 and 38 (36) colony forming unit (CFU)/m3, respectively. The results showed no significant correlation between the levels of PM2.5 and concentrations of bacteria (p < 0.05). Staphylococcus species were detected in 8 of 37 (22%) samples in a concentration from 3 to 213CFU/m3. S. epidermidis was detected with the highest frequency followed by S. gallinarum and S. hominis, but S. aureus and methicillin-resistant Staphylococcus aureus (MRSA) were not detected. No significant correlation between the concentrations of bacteria with meteorological parameters was observed (p < 0.05). Our finding showed that, although the study area is sometimes subject to air pollution from PM2.5, the concentration of PM2.5- associated bacteria is relatively low. According to the results, PM2.5 may not be a source of community-associated staphylococcal infections.

Demographic and Clinical Profile of Invasive Staphylococcal Infections in Children Admitted to Pediatric Intensive Care Unit: A Retrospective Study.

ObjectiveStaphylococcal infections are common cause of morbidity and mortality in pediatric intensive care unit (PICU). The objective of this study was to describe the clinical and microbial features, and outcome of patients with invasive staphylococcal infection.Materials and methodsWe conducted a retrospective chart review of the children admitted to PICU with invasive staphylococcal infections. Invasive staphylococcal infection was defined as clinical infection with isolation of Staphylococcus aureus from a normally sterile body site.ResultsA total of 50 children (1 month to 16 years) were identified with staphylococcal infections during the study period. There was male preponderance (75%) with high prevalence in school going children. Among these children, 36% (18) were coagulase-negative (CONS), which were excluded. Of the remaining, 64% (32) were coagulase-positive Staphylococcus aureus, 54% (27) were methicillin-resistant Staphylococcus aureus (MRSA), and 10% (5) were methicillin-susceptible Staphylococcus aureus (MSSA). Community-acquired staphylococcal infections were present in 24 children (CA-MRSA). Pneumonia with empyema was the most common 20 (62%) site of primary staphylococcal infection, followed by blood stream infection 9 (28%) and skin and soft tissue infection 3 (9%). Of the soft tissue infection, three were MRSA, with two had pyopericardium with infective endocarditis. Resistance in MSSA was found to be maximum to penicillin, erythromycin, and ciprofloxacin with no resistance with vancomycin.ConclusionThere is an increase incidence of MRSA among community-acquired staphylococcal infections requiring intensive care management. A larger study on clinical profile of Staphylococcus infection in pediatrics is urgently needed to define the exact magnitude of the problem.How to cite this articleLalitha AV, Rebello G, Chettri S, Reddy M. Demographic and Clinical Profile of Invasive Staphylococcal Infections in Children Admitted to Pediatric Intensive Care Unit: A Retrospective Study. Indian J Crit Care Med 2020;24(9):890–891.

Antibiotic sensitivity and clinical outcomes in staphylococcal scalded skin syndrome.

Staphylococcal scalded skin syndrome causes widespread skin denudation primarily in infants<1 year old. Selection of empiric therapy is complicated by rising rates of antibiotic resistance in community-acquired staphylococcal infections. Consistent with a previous study, this retrospective review found that SSSS-associated isolates were more likely to be clindamycin-resistant and less likely to be methicillin-resistant compared to overall staphylococcal infections. We favor cephalosporins and penicillinase-resistant penicillins (eg, oxacillin) for empiric management of SSSS, with consideration of adding MRSA coverage in communities with high MRSA prevalence or failure to improve following several days of treatment.

Characterization of methicillin-resistant &lt;i&gt;Staphylococcus aureus &lt;/i&gt;isolates from apparently healthy individuals in Malete, Kwara state, Nigeria

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a common and continuously growing cause of nosocomial and community-acquired staphylococcal infections around the world. Screening for colonization with MRSA is a major aspect of control and limiting the spread of infections cause by this organism. We investigated the carriage of MRSA among apparently healthy individuals in four rural villages: Eleburu, Tapa, Atere and Apo all around semi-urban town-Malete, in Moro Local Government of Kwara State, Nigeria.Methods: Nasal swabs were collected from volunteered individuals and were cultured on mannitol salt agar and blood agar for isolation and identification of Staph aureus using standard microbiological techniques. Susceptibility to cefoxitin disc (30 ag) was used to determine MRSA status of the isolates. Molecular method was used to detect the gene responsible for resistance among MRSA isolates. Antimicrobial susceptibility test to commonly prescribed antibiotics was carried out using discs diffusion method.Results: Total number of individuals carrying Staph aureus in their nostrils was 42 (37.2 %). Antibiotics susceptibility profile of Staph aureus isolates showed 100 % resistance to cefuroxime, cefotaxime, cloxacillin and augmentin, and were 87 %, 81 %, 69 % and 23.8 % and 19 % resistant to tetracycline, ceftriaxone, erythromycin, ofloxacin and gentamicin respectively. A total of 6 (14%) Community –Acquired MRSA (CA-MRSA) isolates were recovered from individuals living in these villages. Molecular method detected muc and mecA genes in all the 6 (100%) CA-MRSA isolates and lukS-lukF was detected in 3 (50%) of the isolates.Conclusion: Detection of CA-MRSA strains among these rural dweller indicates that they are harbouring enhance virulence organism that may manifest a more severe disease condition. The danger associated with high prevalence of multidrug resistant Staph aureus and CAMRSA; and its consequential effects of poor drug administration in Nigeria was discussed. There is need to establish a more strict legislation and enforcement on drug control; and a body that would monitor production and appropriate use of antibiotics in the Nigeria.KEYWORDS: CA-MRSA, Staph aureus, Antibiotics, Rural Villages and Molecular Characterization

Nasal Colonization as a Risk Factor for Staphylococcal Infection: a Systematic Review and Meta-Analysis

Staphylococcus aureus (S. aureus) is a Gram-positive bacterium found in clinical and community settings across the world. It is a major cause of both nosocomial and community-acquired staphylococcal infections. Nasal carriage rates of S. aureus and MRSA among hospital and non-hospital centers have been reported in several Nigerian studies. Nevertheless, most of these studies presented local data, and no systematic study has been performed. The aim of this study is to reveal the pooled prevalence of nasal carriage of Staphylococcus aureus and MRSA among hospital and non-hospital population during the last 14 years (2003–2018) using a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Only 41 studies were included in this meta-analysis out of which only 24 studies reported MRSA colonization rates. The Meta-analysis of included studies reveals the pooled random effects estimate of nasal carriage of S. aureus and MRSA in Nigeria to be 41.5% (95% CI: 36.3-46.9) and 36.4% (95% CI: 27.7- 46.1), respectively. The high level of heterogeneity (S. aureus, 94% and MRSA, 92%) found in this study cannot be explained by chance, but by differences in study populations, methodology and geographical regions. Although not all infections are causally related to persistent S. aureus and MRSA carriages, there is sufficient data to show that colonization by MRSA may act as a reservoir that can subsequently develop into an infection, once immunity wanes or immune defenses are breached. Therefore, proper screening and decolonization strategies should be nationally employed.

Emergence of a Staphylococcus aureus Clone Resistant to Mupirocin and Fusidic Acid Carrying Exotoxin Genes and Causing Mainly Skin Infections.

Skin and soft tissue infections (SSTIs) caused by mupirocin-resistant Staphylococcus aureus strains have recently increased in number in our settings. We sought to evaluate the characteristics of these cases over a 43-month period. Data for all community-acquired staphylococcal infections caused by mupirocin-resistant strains were retrospectively reviewed. Genes encoding products producing high-level resistance (HLR) to mupirocin (mupA), fusidic acid resistance (fusB), resistance to macrolides and lincosamides (ermC and ermA), Panton-Valentine leukocidin (PVL) (lukS/lukF-PV), exfoliative toxins (eta and etb), and fibronectin binding protein A (fnbA) were investigated by PCRs in 102 selected preserved strains. Genotyping was performed by SCCmec and agr typing, whereas clonality was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). A total of 437 cases among 2,137 staphylococcal infections were recorded in 2013 to 2016; they were all SSTIs with the exception of 1 case of primary bacteremia. Impetigo was the predominant clinical entity (371 cases [84.9%]), followed by staphylococcal scalded skin syndrome (21 cases [4.8%]), and there were no abscesses. The number of infections detected annually increased during the study years. All except 3 isolates were methicillin susceptible. The rates of HLR to mupirocin and constitutive resistance to clindamycin were 99% and 20.1%, respectively. Among the 102 tested strains, 100 (98%) were mupA positive and 97 (95%) were fusB positive, 26/27 clindamycin-resistant strains (96.3%) were ermA positive, 83 strains (81.4%) were lukS/lukF positive, 95 (93%) carried both eta and etb genes, and 99 (97%) were fnbA positive. Genotyping of methicillin-sensitive S. aureus (MSSA) strains revealed that 96/99 (96.7%) belonged to one main pulsotype, pulsotype 1, classified as sequence type 121 (ST121). The emergence of a single MSSA clone (ST121) causing impetigo was documented. Resistance to topical antimicrobials and a rich toxinogenic profile confer to this clone adaptability for spread in the community.

Community-acquired methicillin-resistant Staphylococcus aureus pyomyositis with myelitis: A rare occurrence with diverse presentation

Staphylococcus aureus is the most common bacterial pathogen implicated in pyomyositis. There are increasing reports of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections. The present case report brings out the diverse clinical manifestations of MRSA infection in the form of paraspinal pyomyositis, myelitis, spinal osteomyelitis, and pneumonia. Molecular typing of the organism confirmed the diagnosis. Patient was successfully treated with vancomycin and surgical drainage. Consideration of the possibility of methicillin-resistance and appropriate antibiotic selection is vital in the treatment of serious community-acquired staphylococcal infections.

Understanding the physiology and adaptation of staphylococci: A post-genomic approach

Staphylococcus aureus as well as coagulase-negative staphylococci are medically highly important pathogens characterized by an increasing resistance rate toward many antibiotics. Although normally being skin and mucosa commensals, some staphylococcal species and strains have the capacity to cause a wide range of infectious diseases. Many of these infections affect immunocompromised patients in hospitals. However, community-acquired staphylococcal infections due to resistant strains are also currently on the rise. In the light of this development, there is an urgent need for novel anti-staphylococcal therapeutic and prevention strategies for which a better understanding of the physiology of these bacteria is an essential prerequisite. Within the past years, staphylococci have been in the focus of genomic research, resulting in the determination and publication of a range of full-genome sequences of different staphylococcal species and strains which provided the basis for the design and application of DNA microarrays and other genomic tools. Here we summarize the results of the project group ‘Staphylococci’ within the research network ‘Pathogenomics’ giving new insights into the genome structure, molecular epidemiology, physiology, and genetic adaptation of both S. aureus and coagulase-negative staphylococci.

Mycotic Pseudoaneurysm and Purulent Pericarditis Attributable to Methicillin-ResistantStaphylococcus aureus

Methicillin-resistant Staphylococcus aureus is now a common isolate of community-acquired staphylococcal infections. We present the first case of concomitant mycotic pseudoaneurysm and purulent pericarditis caused by methicillin-resistant S. aureus. The isolate was found to be SCCmec type I, sequence type 8, and to carry the PVL gene. The patient was successfully treated with a combined surgical and medical approach.

The prevalence and source of methicillin-resistant Staphylococcus aureus (MRSA) in the community in Hong Kong

Although reports of isolation of methicillin-resistant Staphylococcus aureus (MRSA) from patients admitted from the community have increased, few studies have investigated colonization of healthy subjects. This study aimed to determine community levels of MRSA in Hong Kong. Nasal swabs from a cross section of young adults and family units were cultured for MRSA. Antibiotic sensitivities and risk factors for carriage were determined and clonal relationships were investigated by pulsed-field gel electrophoresis (PFGE). Overall carriage was low (1.4%), and associated with health-care exposures (OR 13.56, 95% CI 1.11-165.21). Subjects working in health care yielded multi-resistant MRSA strains, but isolates from non-hospital-exposed subjects were methicillin-resistant only. Strains indistinguishable by PFGE were carried by subjects working together, and some spread to other contacts was observed. MRSA colonization in the community is rare in Hong Kong and is largely associated with working in health care. Community-acquired staphylococcal infections may be treated with agents effective against methicillin-sensitive strains.

Antimicrobial activity of tigecycline (GAR-936) tested against 3498 recent isolates of Staphylococcusaureus recovered from nosocomial and community-acquired infections

Tigecycline is a novel 9- t-butylglycylamido derivative of minocycline that has demonstrated activity against a variety of Gram-positive and -negative bacterial pathogens. In vitro activity of tigecycline and comparator agents was determined for 3498 recent (2000–2003) strains of Staphylococcus aureus recovered from patients with either nosocomial or community-acquired infections. Oxacillin-susceptible and -resistant S. aureus from both patient populations displayed identical results for tigecycline (MIC 50 and MIC 90 results at 0.25 and 0.5 mg/L, respectively) and all strains were inhibited by 1 mg/L or less. While co-resistances to other antimicrobial classes were present in oxacillin-resistant strains, susceptibility to tigecycline remained unaffected, making the compound an attractive candidate for treatment of serious hospital as well as community-acquired staphylococcal infections.

In-Vitro Activity of Fusidic Acid Against Methicillin- Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus (MRSA) infections are endemic in hospitals throughout the world. Recent reports suggest that MRSA, once considered exclusively a nosocomial pathogen, may be an emerging pathogen in low-risk community populations. There have been numerous studies in the past decade about an increasing prevalence of MRSA infections acquired in the community 1. These findings have potentially important implications for the treatment of community-acquired staphylococcal infections. If the prevalence of MRSA colonization in the community is elevated, empiric antimicrobial agents administered to patients with suspected community-acquired S. aureus infections may need to include agents with activity against MRSA. In this study, we aimed to investigate the invitro activity of fusidic acid against MRSA. From January 1999 to December 2001, 91 MRSA strains were isolated from blood samples obtained from patients in our hospital. Antimicrobial susceptibility tests were performed and interpreted according to the National Committee for Clinical Laboratory Standards (NCCLS) guidelines and the criteria recommended by the Comite de L’antibiogramme de la Societe Francaise de Microbiologie, using broth microdilution methodology 2,3. Minimum inhibitory concentration (MIC) breakpoints for fusidic acid were ≤0.25 mg/L for susceptible isolates, 0.5-1 mg/L intermediate resisJournal of Chemotherapy Vol. 16 n. 3 (310-311) 2004

Comparative molecular analysis of community- or hospital-acquired methicillin-resistant Staphylococcus aureus.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a growing public health concern that has been associated with pediatric fatalities. It is hypothesized that the evolution of CA-MRSA is a recent event due to the acquisition of mec DNA by previously methicillin-susceptible strains that circulated in the community. This study investigated the genetic relatedness between CA-MRSA, hospital-associated MRSA (HA-MRSA), and nonmenstrual toxic shock syndrome (nmTSS) isolates. Thirty-one of 32 CA-MRSA isolates were highly related as determined by pulsed-field gel electrophoresis and spa typing yet were distinguishable from 32 HA-MRSA strains. The 31 related CA-MRSA isolates produced either staphylococcal enterotoxin B (n = 5) or C (n = 26), and none made TSS toxin 1. All CA-MRSA isolates tested contained a type IV staphylococcal cassette chromosome mec (SCCmec) element. In comparison, none of the HA-MRSA isolates (n = 32) expressed the three superantigens. Antibiotic susceptibility patterns were different between the CA-MRSA and HA-MRSA isolates; CA-MRSA was typically resistant only to beta-lactam antibiotics. Six of twenty-one nmTSS isolates were indistinguishable or highly related to the CA-MRSA isolates. MnCop, an nmTSS isolate obtained in Alabama in 1986, was highly related to the CA-MRSA isolates except that it did not contain an SCCmec element. These data suggest that CA-MRSA strains may represent a new acquisition of SCCmec DNA in a previously susceptible genetic background that was capable of causing nmTSS. CA-MRSA poses a serious health risk not only because it is resistant to the antibiotics of choice for community-acquired staphylococcal infections but also because of its ability to cause nmTSS via superantigen production.

Community-acquired methicillin-resistant Staphylococcus aureus infections: a new source for nosocomial outbreaks.

Over a 19-month period, 165 patients with 183 infections caused by community-acquired, methicillin-resistant Staphylococcus aureus were seen at Henry Ford Hospital in Detroit, Michigan. The proportion of community-acquired staphylococcal infections resistant to methicillin rose from 3 % in March 1980 to 38% in September 1981. Drug abuse, serious underlying illness, previous antimicrobial therapy, and previous hospitalization were all associated with the development of this infection. Concurrent with the community epidemic was a nosocomial epidemic of methicillin-resistant S. aureus infection, which accounted for 30.6% of all nosocomial staphylococcal infections in January 1981. Control measures that included isolation, discharge precautions for carriers, and eradication of employee carriage were effective in preventing nosocomial transmission. The prevalence of methicillin-resistant S. aureus carriage among employees was 0.7%. Methicillin-resistant S. aureus may originate in the community as well as in the hospital, and presents a threat to patients in both settings.

Staphylococci in community-acquired infections: Increased resistance to penicillin.

One hundred patients with community-acquired staphylococcal infections of the skin and soft tissues were treated in the Emergency Ward of Cleveland Metropolitan General Hospital from June to October of 1974. Each staphylococcal infection was considered community-acquired if, within two weeks prior to being treated for the first time, the patient had not received antibiotics, had not been hospitalized, and had not been in contact with other recently hospitalized persons. Of 100 community-acquired staphylococcal infections, 85 were resistant to penicillin. Almost no resistance to other tested antibiotics was observed. Unless indicated otherwise by bacteriologic testing, penicillin is a poor drug of choice in those skin and soft tissue infections suspected of harboring staphylococci.