Community-acquired Methicillin-resistant Staphylococcus Aureus Infections Research Articles

Community-acquired methicillin-resistant Staphylococcus aureus from skin and soft tissue infections (in a sample of Egyptian population): analysis of mec gene and staphylococcal cassette chromosome

BackgroundStaphylococcus aureus has been recognized as an important pathogen associated with inpatients and community infections. Community-acquired methicillin-resistant S. aureus (CA-MRSA) infections commonly present as skin and soft-tissue infections (SSTIs). Treatment often includes incision and drainage with or without adjunctive antibiotics. ObjectivesThis study aimed to identify CA-MRSA infections both phenotypically and genotypically, to determine their spectrum of antibiotic resistance, and to establish the best scheme for molecular distinction between hospital-acquired MRSA (HA-MRSA) and CA-MRSA by staphylococcal cassette chromosome mec (SCCmec) typing and detection of Panton Valentine leukocidin (PVL). Materials50 swabs, from skin and soft tissue of infected lesions of outpatients attending the dermatology department of the Medical School, Alexandria University, were collected. Additionally, a nasal swab was taken from every participant. MethodsCollection of swabs from the infected skin and soft tissues, followed by laboratory testing to phenotypically and genotypically identify MRSA. Also, nasal swabs were taken from every patient to identify MRSA colonization. ResultsStaphylococcus aureus strains were identified in 38 (76%) of the 50 clinical isolates. 18 (47.37%) out of the 38 S. aureus strains were resistant to oxacillin and cefoxitin discs, were penicillin binding protein 2a (PBP2a) producers, and were initially diagnosed as MRSA. All of the 18 strains were definitively diagnosed as MRSA by mecA gene detection using real time PCR, while only six (33.33%) strains were PVL positive. Using the sets of primers of Zhang et al.: nine (50%) out of the 18 CA-MRSA strains were SCCmec type V, and one (5.56%) was SCCmec type IVc. Then, using the set of primers by Oliveira et al., two (25%) out of the eight untypable MRSA strains were found to be SCCmec type IV, and six (75%) remained untypable. ConclusionsCA-MRSA must be considered when treating skin and soft tissue infections, especially in developing countries. Empirical use of agents active against CA-MRSA is warranted for patients presenting with serious SSTIs.

MRSA Thyroiditis and Thyrotoxicosis

Objective: 1) Learn that methicillin-resistant staphylococcus aureus (MRSA) thyroiditis causing thyrotoxicosis is a rare and potentially life-threatening condition. 2) Understand the diagnosis and management of suppurative thyroiditis and related thyrotoxicosis. 3) Understand the rising incidence of both community-acquired and hospital-acquired MRSA infections. Method: We present a patient with MRSA thyroiditis and thyrotoxicosis who was evaluated by the otolaryngology–head and neck surgery service of an academic, tertiary care hospital in 2012. The literature was also reviewed through a directed PubMed search, and a relevant case was identified and discussed. Results: A patient was transferred from an outside hospital in respiratory failure with a recent history of progressive neck pain and dysphagia. Computed tomography of the neck revealed an enlarged and inflamed thyroid gland, which was causing airway compression. Thyrotoxicosis was subsequently identified. MRSA was cultured in samples from an ultrasound guided thyroid biopsy and a surgical debridement. Antibiotics were started, and the thyrotoxicosis was followed clinically. With this management, the thyrotoxicosis resolved, and hypothyroidism immediately ensued. A literature review revealed only one previously reported case of MRSA thyroiditis and thyrotoxicosis, which resolved with medical management. Conclusion: MRSA thyroiditis with associated thyrotoxicosis represents a rare complication of a bacterium that is becoming more common in community and hospital settings. To our knowledge, this is the second reported case of this particular clinical entity. Prompt identification of a causative organism and thyrotoxicosis can allow for potentially life-saving interventions.

Multicenter Evaluation of the LightCycler MRSA Advanced Test, the Xpert MRSA Assay, and MRSASelect Directly Plated Culture with Simulated Workflow Comparison for the Detection of Methicillin-Resistant Staphylococcus aureus in Nasal Swabs

Rapid detection of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) followed by appropriate infection control procedures reduces MRSA infection and transmission. We compared the performance and workflow of two Food and Drug Administration-approved nucleic acid amplification assays, the LightCycler MRSA Advanced Test and the Xpert MRSA test, with those of directly plated culture (MRSASelect) using 1202 nasal swabs collected at three U.S. sites. The sensitivity of the LightCycler test (95.2%; 95% CI, 89.1% to 98.4%) and Xpert assay (99%; 95% CI, 94.8% to 100%) did not differ compared with that of culture; the specificity of the two assays was identical (95.5%; 95% CI, 94.1% to 96.7%) compared with culture. However, sequencing performed on 71 samples with discordant results among the three methods confirmed the presence of MRSA in 40% of samples that were positive by both molecular methods but negative by culture. Workflow analysis from all sites including batch runs revealed average hands-on sample preparation times of 1.40, 2.35, and 1.44 minutes per sample for the LightCycler, Xpert, and MRSASelect methods, respectively. Discrete event simulation analysis of workflow efficiencies revealed that the LightCycler test used less hands-on time for the assay when greater than eight batched samples were run. The high sensitivity and specificity, low hands-on time, and efficiency gains using batching capabilities make the LightCycler test suitable for rapid batch screening of MRSA colonization.

Clinical and microbiological characteristics of communityacquired methicillin-resistant Staphylococcus aureus pneumonia

Methicillin-resistant Staphylococcus aureus (MRSA) infections now occur in healthy adults in community settings. We searched the PubMed database to identify relevant articles on the clinical presentation, epidemiology, virulence, and treatment of community-acquired MRSA (CA-MRSA) infections, including pneumonia. This information was summarized in a narrative review.MRSA infections cause approximately 30 infections per 100,000 people per year in the USA, and twenty percent of these infections are secondary to CA-MRSA. These community-acquired infections often involve the skin and subcutaneous tissue but can also involve visceral tissues such as the lung and bone. The overall mortality in patients with invasive disease is approximately 10%; it approaches 50% in patients with pneumonia. The bacterial isolates from these infections have the staphylococcal chromosome cassette mec types 4 and 5. This genetic characteristic produces beta-lactam resistance and helps distinguish these isolates from hospital- acquired MRSA, which usually have mec types 1-3. Some CA-MRSA isolates release the Panton-Valentine leukocidin (PVL), which causes neutropenia and tissue necrosis; other toxins also contribute to the virulence of these infections. Empiric therapy should include vancomycin or linezolid. CA-MRSA infections can have fulminant courses and high mortality rates. Physicians should consider these infections as possible emergencies with a high risk for organ system failure and shock.

Clinical and microbiological characteristics of communityacquired methicillin-resistant Staphylococcus aureus pneumonia

Methicillin-resistant <em>Staphylococcus aureus</em> (MRSA) infections now occur in healthy adults in community settings. We searched the PubMed database to identify relevant articles on the clinical presentation, epidemiology, virulence, and treatment of community-acquired MRSA (CA-MRSA) infections, including pneumonia. This information was summarized in a narrative review.MRSA infections cause approximately 30 infections per 100,000 people per year in the USA, and twenty percent of these infections are secondary to CA-MRSA. These community-acquired infections often involve the skin and subcutaneous tissue but can also involve visceral tissues such as the lung and bone. The overall mortality in patients with invasive disease is approximately 10%; it approaches 50% in patients with pneumonia. The bacterial isolates from these infections have the staphylococcal chromosome cassette <em>mec</em> types 4 and 5. This genetic characteristic produces beta-lactam resistance and helps distinguish these isolates from hospital- acquired MRSA, which usually have <em>mec</em> types 1-3. Some CA-MRSA isolates release the Panton-Valentine leukocidin (PVL), which causes neutropenia and tissue necrosis; other toxins also contribute to the virulence of these infections. Empiric therapy should include vancomycin or linezolid. CA-MRSA infections can have fulminant courses and high mortality rates. Physicians should consider these infections as possible emergencies with a high risk for organ system failure and shock.

Commercially Distributed Meat as a Potential Vehicle for Community-Acquired Methicillin-Resistant Staphylococcus aureus

The incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection has been increasing; however, the sources of infection remain unclear. Therefore, we investigated the involvement of meat as a possible mediator of CA-MRSA infection. We examined the distribution of MRSA strains in commercially distributed raw meat samples (n = 197) and diarrheal stool samples of outpatients (n = 1,287) that were collected in Oita Prefecture, Japan, between 2003 and 2009 for routine legal inspections. Fourteen MRSA strains were isolated from three meat and 11 stool samples. Among these, seven isolates from three meat and four stool samples exhibited the same epidemiological marker profiles [coagulase type III, staphylococcal enterotoxin C, staphylococcal chromosomal cassette mec (SCCmec) type IV, ST8, spa type 606 (t1767), and toxic shock syndrome toxin-1 (TSST-1) producing type]. Furthermore, of the seven strains, three isolates from two meat samples and one stool sample collected in 2007 exhibited completely identical characteristics with respect to phage open reading frame (ORF) typing, pulsed-field gel electrophoresis, and drug susceptibility profiles. The results suggest that commercially distributed meat could play a role in the prevalence of CA-MRSA in the community.

Community-acquired Methicillin-Resistant Staphylococcus aureus Bilateral Acute Dacryocystitis in a Neonate

Dear Editor, Bilateral acute dacryocystitis in neonates is a rare condition with very few cases described in literature.[1–3] We present a case of bilateral acute dacryocystitis secondary to congenital nasolacrimal duct obstruction (CNLDO), caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). This was the first case of bilateral acute dacryocystitis secondary to CNLDO, caused by CA-MRSA in our Medline search result, hence we report the case. A 12-day-old newborn boy (delivered at home) with bilateral acute dacryocystitis since two days was referred to us by his pediatrician. The mother had taken antibiotics for bilateral MRSA mastitis during pregnancy. Ophthalmic examination revealed bilateral lacrimal sac abscess. The size of the lacrimal sac abscess was approximately 1.5 × 1.5 cm OD and 1.5 × 1.0 cm OS [Fig. 1a]. Mild compression of the lacrimal sac resulted in regurgitation of purulent discharge from the lower puncta. Both the eyelids showed edema and erythema. The remainder of his ocular examination was normal. Blood and conjunctival swab were sent for culture and sensitivity.Figure 1a: The clinical photograph of the face at the time of presentation showing bilateral acute dacryocystitis with lacrimal abscess formationThe newborn was hospitalized and intravenous amoxicillin/clavulanic acid and amikacin were started. Over the next 12 h, swelling and redness increased with bilateral external fistula formation [Fig. 1b]. Bilateral incision and drainage of the abscess was performed under general anesthesia. Approximately 2 ml of thick, yellowish collection was aspirated from each site and sent for culture. Gram stain revealed Gram-positive cocci, fibrinous exudates, and both inflammatory and red blood cells. Blood culture was negative. Swab cultures demonstrated Staphylococcus aureus, sensitive to vancomycin, clindamycin and rifampicin, but resistant to methicillin, amoxicillin, amikacin and ciprofloxacin. Mother's breast milk was sterile but recent breast swab culture revealed same organism with identical antibiotic susceptibility. The patient was switched to vancomycin. Topical 5% vancomycin solution was given QID. The lacrimal swelling and erythema resolved completely over the course of two days [Fig. 1c]. The mother was also re-treated for mastitis. Probing and irrigation of the nasolacrimal duct was performed in both eyes two weeks after presentation which resolved CNLDO. Patient was free from lacrimal symptoms at six month's follow-up.Figure 1b: The clinical photograph showing increased inflammatory signs with external fistula formation OU even after 12 hours of hospitalization and intravenous antibioticsFigure 1c: The clinical photograph showing reduced lacrimal and periocular swelling on day-2 postoperativelyOphthalmic CA-MRSA infections have been previously reported.[4] Neonates may acquire CA-MRSA vertically from their mother's contaminated breast milk or by skin-to-skin contact.[5] CA-MRSA is resistant to mainly beta-lactam antibiotics e.g. penicillin and cephalosporin. On the other hand, Hospital-acquired MRSA is resistant to multiple antibiotics.[4] In the present case, organisms were not only resistant to beta-lactams but also to quinolones and aminoglycosides. Recently, multi-drug-resistant CA-MRSA has also been observed.[6] The probable source of infection, in the present case, was maternal breast skin, which reached the nasolacrimal system via skin-to-skin contact during breast feeding. Isolation of MRSA with identical antibiotic susceptibility, from mother's breast swabs, conjunctival sac as well as purulent material from lacrimal sac, supports a cause-effect relationship of vertically acquired CA-MRSA in the present case. To avoid treatment delay, vertical transmission of CA-MRSA should be suspected even in cases of acute dacryocystitis involving otherwise healthy newborns with positive family history of MRSA infection.

Community-Acquired Methicillin-Resistant Staphylococcus Aureus (CA-MRSA) Brain Abscess

In Brief A 64-year-old man was admitted with new-onset seizures. His examination was normal with no neurological deficits. Computed tomography of the brain showed a hypodense left parietal lobe lesion, but he insisted on early discharge. He was readmitted 12 days later with recurrent seizures. Brain imaging showed significant increase in size of brain mass. Emergent surgery revealed an abscess, which subsequently grew methicillin-resistant Staphylococcus aureus (MRSA). The patient was treated postoperatively with intravenous vancomycin for 8 weeks. The patient had no risk factors for hospital-acquired infection but recalled having a furuncle 6 weeks before presentation. The diagnosis of community-acquired MRSA abscess was made epidemiologically and on antibiotic sensitivity profile. Community-acquired MRSA infections are becoming increasingly prevalent with ever-increasing spectrum of invasive presentations. Only 4 cases of Community-acquired MRSA brain abscess have been previously reported, of which 3 had fatal outcomes. In contrast, our patient had complete recovery. A reappraisal of current treatment guidelines for community-acquired brain abscesses, which do not include vancomycin for empiric coverage of MRSA, should be considered. Community-acquired Methicillin-resistant Staphylococcus Aureus (CA-MRSA) is increasingly being recognized as an organism with invasive potential causing an ever-increasing spectrum of diseases. One such presentation is community acquired brain abscess which is a potentially life threatening disease. Our case highlights the need for increasing awareness of CA-MRSA as potential pathogen for brain abscess and a critical reappraisal of current treatment guidelines for community-acquired brain abscess, which do not include empiric coverage of CA-MRSA with Vancomycin.

Control of methicillin resistant Staphylococcus aureus infection utilizing a novel immunostimulatory peptide

The emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a serious health concern worldwide that requires new therapeutic approaches that extend beyond the development and use of new antibiotics. In this study, a conformationally biased, response-selective agonist of human C5a, known as EP67, was used to induce host innate immunity as a therapeutic method of reducing CA-MRSA infections. Using a murine model of dermonecrosis we show that EP67 treatment effectively limits CA-MRSA infection by promoting cytokine synthesis and neutrophil influx. In contrast, EP67 was ineffective in reducing lesion formation in C5a receptor (CD88(-/-)) knockout mice, indicating that EP67 activates host innate immunity by engagement of CD88 bearing cells. These results suggest that EP67 may serve as a novel immunotherapeutic for prevention and treatment of CA-MRSA dermal infection.

Higher incidence of perineal community acquired MRSA infections among toddlers

BackgroundA six-fold increase in pediatric MRSA infections, prompted us to examine the clinical profile of children with MRSA infections seen at Mercy Children's Hospital, Toledo, Ohio and to characterize the responsible strains.MethodsRecords were reviewed of pediatric patients who cultured positive for MRSA from June 1 to December 31, 2007. Strain typing by pulsed field gel electrophoresis (PFT) and DiversiLab, SCCmec typing, and PCR-based lukSF-PV gene (encodes Panton-Valentine leukocidin), arginine catabolic mobile element (ACME) and cap5 gene detection was performed.ResultsChart review of 63 patients with MRSA infections revealed that 58(92%) were community acquired MRSA (CAMRSA). All CAMRSA were skin and soft tissue infections (SSTI). Twenty five (43%) patients were aged < 3 yrs, 19(33%) aged 4-12 and 14(24%) aged 13-18. Nineteen (76%) of those aged < 3 yrs had higher incidence of perineal infections compared to only 2(11%) of the 4-12 yrs and none of the 13-18 yrs of age. Infections in the extremities were more common in the older youth compared to the youngest children. Overall, there was a significant association between site of the infection and age group (Fisher's Exact p-value < 0.001). All CAMRSA were USA300 PFT, clindamycin susceptible, SCCmec type IVa and lukSF-PV gene positive. Nearly all contained ACME and about 80% were cap5 positive. Of the 58 USA300 strains by PFT, 55(95%) were also identified as USA300 via the automated repetitive sequence-based PCR method from DiversiLab.ConclusionsCAMRSA SSTI of the perineum was significantly more common among toddlers and that of the extremities in older children. The infecting strains were all USA300 PFT. Further studies are needed to identify the unique virulence and colonization characteristics of USA300 strains in these infections.

Management of Skin and Soft Tissue Infections in Community Practice Before and After Implementing a "Best Practice" Approach: An Iowa Research Network (IRENE) Intervention Study

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a major pathogen among skin and soft tissue infections (SSTIs). Most CA-MRSA infections are managed initially on an outpatient basis. It is critical that primary care clinicians recognize and appropriately treat patients suspected of having such infections. To identify and evaluate best methods and procedures for primary care clinicians to manage skin and soft tissue infections. Preintervention/postintervention study in eight Iowa Research Network offices conducted between October 2007 and August 2010. We reviewed medical records of 216 patients with SSTI before a set of interventions (preintervention) and 118 patients after the intervention (postintervention). Included a focus group meeting at each office, distribution of a modified Centers for Disease Control and Prevention (CDC) algorithm, "Outpatient Management of MRSA Skin and Soft Tissue Infections," education handouts, and an office policy for patients with skin infections. Proportion of subjects who were prescribed an antibiotic that would cover MRSA at the initial visit and proportion who were prescribed an antibiotic that would cover MRSA at any time. Three hundred sixty-eight forms (244 preintervention and 124 postintervention) were returned; 216 (89%) preintervention forms and 118 (95%) postintervention forms were usable. Multivariable logistic regression models found statistically significant and independent factors associated with MRSA coverage at the initial visit included being in the postintervention rather than the preintervention group, having an abscess component compared with cellulitis alone, having a culture sent, being prescribed two or fewer antibiotics, and not being hospitalized. The CDC algorithm was feasible for offices to use. Following a discussion of SSTI management in the outpatient setting, use of MRSA coverage increased both initially and overall. Thus, involving clinicians in a discussion about guidelines rather than simply providing guidelines or a didactic session may be a useful way to change physician practices.

Prevalence and characterization of methicillin-resistant Staphylococcus aureus among healthy children in a city of Argentina

Community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a major global problem. Healthy carriers of S. aureus strains have an important role in the dissemination of this bacterium. The aim of this study was to estimate the prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) carriage among healthy children in a city of Buenos Aires province, Argentina, and to determine the potential risk factors for its acquisition. We also described the molecular features of MRSA strains circulating in this population. S. aureus carriage was investigated in all children attending the last year of kindergarten during the 2008 school- year period. Household contacts of MRSA carriers were also screened. Of 316 healthy children, 98 (31.0%) carried S. aureus, including 14 MRSA carriers (4.4%) and 84 methicillin susceptible S. aureus (MSSA) carriers (26.6%). All MRSA isolates carried the SCC mec type IV cassette. Eight of the fourteen isolates were closely related to the clone responsible for most severe community-acquired MRSA infections caused in our country (CAA: PFGE A, SCC mec IV, spa t311, ST5). Two subtypes (A 1 and A 2) were distinguished in this group by PFGE. Both had agr type II and presented the same virulence determinants, except for PVL coding genes and sea that were only harbored by subtype A 1. Our results, based on the analysis of MRSA isolates recovered in the screening of healthy children, provide evidence of a community reservoir of the major CA-MRSA clone described in Argentina.

Surveillance of methicillin-resistant Staphylococcus aureus isolated in Torino (northwest Italy)

Nosocomial infections by methicillin-resistant Staphylococcus aureus (MRSA) are an increasing cause of morbidity and mortality. Recently, a worldwide increase of community-acquired MRSA infections has also been recorded. The purpose of this study was to assess the frequency of MRSA isolation from in- and outpatients admitted to an academic teaching hospital near Torino (northwest Italy) in 1 year and to characterize 90 clinical isolates of MRSA collected in the same period. Antimicrobial susceptibility and the presence in the isolates of the Panton–Valentine leukocidin (PVL) gene were assessed. Molecular epidemiology was performed by SCC mec and capsule typing, and by pulsed-field gel electrophoresis. The global proportion of MRSA isolated was 33.1%. Characterization performed on 90 MRSA revealed a high percentage of resistance to ciprofloxacin and erythromycin, and the presence of the PVL gene in one strain only. Most of the MRSA strains circulating in the Torino district belonged to SCC mec types II and I, and the 67.6% resulted positive for the cap 5 gene. The pulsotype analysis permitted to observe a clonal heterogeneity of the isolates and a higher similarity in relation to singular mec types; only few nosocomial clones could account for a local outbreak of a sporadic isolate.

A case of toxic shock syndrome caused by community-acquired MRSA infection: considering the choice of antibiotics

市中型メチシリン耐性黄色ブドウ球菌（community-acquired methicillin-resistant Staphylococcus aureus: CA-MRSA）による感染症がまだ少ないわが国で，toxic shock syndrome（TSS）の初期治療を計画する上で，どのように介入すべきかを検討した。症例は生来健康な31歳の男性。入院8日前に下腿II度深部熱傷（一部III度に伸展）を受傷し外来治療中であった。入院当日にTSSの診断基準を満たし，下腿熱傷部の壊死組織からmethicillin resistant Staphylococcus aureus（MRSA）が培養された。同菌の薬剤感受性が，一般的には院内感染によるMRSAでは感受性のないST合剤やCLDMに感受性が認められたため，CA-MRSAを疑い，菌株の遺伝子検索を行った。その結果，SCCmec type IVであり，CA-MRSAと判断した。現在，本邦のTSSの起因菌はMSSAの頻度が高く，CA-MRSAの頻度は低いと考えられるため，penicillin（PC）系もしくはcephalosporin系抗菌薬に加えてCLDMが第一選択薬となる。本邦のようにCA-MRSAの頻度が極めて低いと考えられる地域では，TSS症例に対してルーチンの抗MRSA薬の使用は避けるべきであるが，第一選択薬で症状の改善が認められない場合は，CA-MRSAによるTSSを考慮しCLDMに加えて，抗MRSA薬の投与を考慮する必要がある。今後，本邦でもCA-MRSAの割合が増えてくることが予想されるためCA-MRSAの疫学変化に注意が必要である。

Universal MRSA Nasal Surveillance: Characterization of Outcomes at a Tertiary Care Center and Implications for Infection Control

Recognition of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage by active surveillance cultures has been widely debated. Our institution implemented universal nasal screening by polymerase chain reaction (PCR) for MRSA and isolation of screen positive patients in December 2007. Here we present data about the correlation between screen positivity and subsequent development of infection and the impact of isolation on surgical site infection rates. This was a retrospective, observational study from January 1, 2008, through June 30, 2008, on all inpatient admissions with a nasal MRSA PCR screen. Genotype of 15 MRSA blood isolates was determined utilizing the Diversilab® (bioMérieux, Hazelwood, MO) system. A phenotypic rule was deduced and utilized for analyzing all MRSA clinical isolates. 5375 patients were screened at ≤48 hours following admission. 581 MRSA positive nasal carriers (10.80%) were identified. 496 (85.3%) were asymptomatic MRSA nasal carriers. There were a total of 158 MRSA clinical infections. 85 (14.6%) MRSA nasal carriers had clinical infection. Of the 4794 (89.1%) non-nasally colonized patients, 73 (1.5%) had MRSA clinical infection. MRSA surgical site infection rate remained unchanged during the intervention period. Phenotypic predictive rule inferred 59.8% community-acquired MRSA (CA-MRSA) infections and 40% hospital-acquired MRSA (HA-MRSA) infections. Our study showed a positive correlation between having a nasal screen positivity and subsequent development of infection. Isolation of MRSA screen positive patients alone as an intervention did not reduce the surgical site infection rates. Since most of our isolates are CA-MRSA, our institution is implementing several new interventions to further reduce the incidence of HA-MRSA conditions.

Increasing Threat of Community-Acquired Methicillin-Resistant Staphylococcus aureus

IntroductionMethicillin-resistant Staphylococcus aureus (MRSA) has emerged as a serious problem in the community. The objective of this prospective study was to report the frequency of community-acquired MRSA (CA-MRSA) isolates at King Fahd Hospital of the University in the Eastern Province of Saudi Arabia, to describe the spectrum of disease observed in patients infected with CA-MRSA and to study the antibiotic susceptibility profile. MethodsIsolates of CA-MRSA from King Fahd Hospital of the University were reviewed prospectively during an 8-year period, from January 2001 to December 2008. ResultsThe prevalence of CA-MRSA infections increased from 9.9 per 10,000 admissions in 2001 to 67 per 10,000 admissions in 2008 (P < 0.001). The number of CA-MRSA increased from 67 isolates in the first part of the study (2001–2004) to 176 cases in the second period of the study (2005–2008), and the percentage of CA-MRSA/of the total MRSA isolates rose from 20% in the first period to 59% in the second period of the study (P < 0.001). Soft tissue infections accounted for 198 (81%) of the 243 cases of CA-MRSA infections and invasive infections in 14 (7%) patients. The antibiotic susceptibility pattern has also changed with increasing levels of resistance to erythromycin, tetracycline, clindamycin, ciprofloxacin and gentamicin. ConclusionContinued emergence of MRSA in the community is a public-health problem that demands increased vigilance in the diagnosis and management of suspected and confirmed staphylococcal infections.

Methicillin-Resistant Staphylococcus aureus in Diabetic Foot Infections

Diabetic foot ulcers are often complicated by infection. Among pathogens, Staphylococcus aureus predominates. The prevalence of methicillin-resistant S. aureus (MRSA) in infected foot ulcers is 15-30% and there is an alarming trend for increase in many countries. There are also data that recognize new strains of MRSA that are resistant to vancomycin. The risk for MRSA isolation increases in the presence of osteomyelitis, nasal carriage of MRSA, prior use of antibacterials or hospitalization, larger ulcer size and longer duration of the ulcer. The need for amputation and surgical debridement increases in patients infected with MRSA. Infections of mild or moderate severity caused by community-acquired MRSA can be treated with cotrimoxazole (trimethoprim/sulfamethoxazole), doxycycline or clindamycin when susceptibility results are available, while severe community-acquired or hospital-acquired MRSA infections should be managed with glycopeptides, linezolide or daptomycin. Dalbavancin, tigecycline and ceftobiprole are newer promising antimicrobial agents active against MRSA that may also have a role in the treatment of foot infections if more data on their efficacy and safety become available.

Otolaryngologic Community-Acquired MRSA Infections in a Suburban Private Practice

A retrospective review was conducted of all cases of head and neck community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections seen in the senior author's suburban private practice during a 12-month period. An office and hospital chart review was performed for all patients identified with culture-positive CA-MRSA infections. Several parameters were evaluated, including site of infection, prior therapy, imaging, comorbid disease, culture and sensitivities, surgical and medical management, and long-term results. Of the 10 patients identified, 3 had infections of nasal soft tissues, 3 had infections of the lips, 2 had infections of the paranasal sinus, 1 had an infection of the chin, and 1 had a diffuse, hemifacial infection. All patients were managed successfully with a combination of surgical drainage, wound care, and antibiotics. CA-MRSA is a burgeoning problem in otolaryngology. Appropriate management-including early recognition, appropriate empirical therapy, prompt and thorough surgical drainage with culture and sensitivities, correct antibiotic choice, and meticulous postoperative care-appears to offer excellent results.

Infecciones por Staphylococcus aureus resistente a meticilina adquirido en la comunidad en niños

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections were first reported in the 1990s. Young, healthy individuals are frequently affected. The incidence of CA-MRSA in Spain is increasing. All children seen between August 2006 and January 2009 with CA-MRSA infections were included. The S. aureus isolates were studied by conventional techniques, their antibiotic susceptibility by agar disk diffusion, the presence of mecA gene was detected by multiplex polymerase chain reaction (PCR) and the gene encoding the Panton-Valentine leukocidin (PVL) by conventional PCR. CA-MRSA colonization was studied both in patients and their family members. CA-MRSA was isolated in 15 samples from 12 patients, aged between 6 days and 14 years. Half of them were not native. Eight patients required hospital admission. The most common clinical presentation was skin and soft tissue infection (92%). Secondary CA-MRSA bacteraemia was present in two patients. All strains were PVL producers and two were resistant to macrolides associated to methicillin resistance and one of them was also resistant to lincosamides. An intra-familial transmission was identified. The clinical outcome was favourable in all patients. CA-MRSA infections are emerging in Spain. Empirical treatment of skin and soft tissue infections should not be changed, since their incidence is still low. The drainage of CA-MRSA suppurative infections plays an important role in their treatment. Clindamycin or trimethoprim-sulfamethoxazole should be used for mild or moderate skin and soft tissue infections. Controlling the spread of these strains presents a challenge in the community today.

Staphylococcus aureus Meningitis

Staphylococcus aureus meningitis is a challenging disease and little is known about its epidemiology. There are no established management guidelines. We retrospectively reviewed the clinical information, bacteriologic data, and outcomes of all 33 patients with cerebrospinal fluid (CSF) cultures positive for S aureus seen at a single urban teaching hospital from 1999 to 2008. Pulsed-field gel electrophoresis (PFGE) and polymerase chain reaction for staphylococcal cassette chromosome mec (SCCmec), accessory gene regulator (agr) typing, and Panton-Valentine leukocidin (PVL) loci were done on methicillin-resistant S aureus (MRSA) CSF isolates starting in 2005. S aureus caused 12 (36%) cases of postoperative and 21 (64%) cases of hematogenous meningitis. MRSA isolates were found in 6 (50%) cases of postoperative and 10 (48%) cases of hematogenous meningitis. Twelve (75%) of the 16 MRSA infections occurred in the last 5 years of the study. Hematogenous meningitis was associated with older age (p = 0.04), injection drug use (p < 0.01), community-acquired infection (p < 0.01), underlying disease (p = 0.01), staphylococcal infection outside the central nervous system (p = 0.01), altered mental status (p = 0.02), fever (p = 0.01), septic shock (p = 0.03), and bacteremia (p < 0.01). The analysis of the 9 MRSA isolates showed 3 PFGE types: 3 USA100 (33%), 5 USA300 (56%), and 1 USAnot100-1100 (11%). For SCCmec typing, there were 2 (22%) type II and 7 (78%) type IV. All USA300 strains were SCCmec IVa. For agr typing, there were 5 (56%) type I and 4 (44%) type II. Three isolates (33%) were positive for the PVL gene and were USA300 strains. Most patients received nafcillin or vancomycin with or without rifampin or trimethoprim/sulfamethoxazole for a mean period of 17 days (range, 1-42 d). Overall mortality was 36%, and it was associated with community-acquired infection (p = 0.02). Postoperative and hematogenous S aureus meningitis are distinct clinical syndromes. S aureus hematogenous meningitis has devastating clinical consequences and elevated mortality rates, especially if it is acquired in the community. The incidence of MRSA meningitis increased over the last 5 years of the study. Treatment of choice is nafcillin for methicillin-sensitive strains and vancomycin for MRSA strains. The addition of trimethoprim/sulfamethoxazole or rifampin to vancomycin is recommended in severe cases and community-acquired MRSA infections. Linezolid is also a good option due to its good CSF penetration and favorable case reports. The mortality rate is higher in infections acquired in the community.