Epidemiology and susceptibilities of methicillin-resistant Staphylococcus aureus in Northeastern Ohio

Staphylococcus aureus in poultry, with special emphasis on methicillin-resistant strain infection: A comprehensive review from one health perspective

Staphylococcus aureus is a Gram-positive coccus normally present on the skin and internal organs of animals, birds, and humans. Under certain conditions, S. aureus could produce septicemia and affection of the skin, joints, and heart, as well as sepsis and death. The pathogenicity of S. aureus is associated with the presence of some virulent surface proteins and the production of some virulent toxins and enzymes. This pathogen is considered one of the most important and worldwide foodborne causes as it is incriminated in most cases of food poisoning. The hazardous use of antibiotics in the veterinary field leads to the development of multidrug-resistant S. aureus strains that can be transmitted to humans. The incidence of methicillin-resistant S. aureus (MRSA) strains has increased globally. These resistant strains have been detected in live animals, poultry, and humans. In addition, retail animal products, especially those of avian origin, are considered the main source of MRSA strains that can be easily transmitted to humans. MRSA infection is regarded as nosocomial or occupational. Humans get infected with MRSA strains through improper handling or preparation of contaminated animals or poultry carcasses or improper cooking with contaminated meat. Live birds also can transmit MRSA to close-contact workers in poultry farms. Transmission of MRSA infection in hospitals is from an infected individual to a healthy one. Prevention and control of MRSA are based on the application of hygienic measures in farms as well as proper processing, handling, and cooking of retail poultry products. The cooperation between veterinary and human practitioners is a must to avoid the possibility of zoonotic transmission. Accordingly, this review focused on the sources and transmission of MRSA infection, virulence and resistance factors, incidence and prevalence in poultry and different products, antibiotic resistance, and prevention and control strategies.

Clinical Spectrum and Resistance Profile of Staphylococcus Infections in a Peri Urban Tertiary Care Hospital

Staphylococcus may be evaluated to be a serious microorganism to colonizes and contaminate both the healthy and immuno-competent people in the community along with the hospitalized patients with decreased immunity. This bacterium has been commonly present on the skin and in the nasal cavity of the human body. In the particular sites the organisms may give rise to local diseases of the nose, urethra, vagina and gastrointestinal tract, skin however most of them are minor and not associated with any mortality. S. aureus as well as coagulase-negative staphylococcus which are gram-positive bacteria that lives on the upper respiratory, mouth and skin structure creation, are the possible element for nosocomial and opportunistic disease in humans as well as in animals. Major complications involved with staphylococcus involved SSI, bullous impetigo, skin & soft tissues infection, bacteremia, pulmonary infections etc. The situation is further complicated by methicillin resistance in staphylococcus. MRSA/MRCoNS are considered as the emerging cause of hospital-acquired infections. it is very necessary to quantify the load of infections in order to achieve good hospital infection control policies. Furthermore, the morbidity and mortality rate may also be reduced in the same manner.

Trends in Antibiotic Resistance Among Ocular Microorganisms in the United States From 2009 to 2018

Question

What are the antibiotic resistance profiles and trends among common ocular pathogens across the United States?

Findings

In this cross-sectional study of more than 6000 ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae collected between 2009 and 2018, methicillin resistance and multidrug resistance were prevalent among staphylococci. Antibiotic resistance profiles were mostly unchanged during 10 years.

Meaning

These in vitro antibiotic resistance data may assist clinicians in selecting appropriate antibiotics for treatment of ocular infections.

Importance

Antibiotic resistance in ocular infections can affect treatment outcomes. Surveillance data on evolving antibacterial susceptibility patterns inform the treatment of such infections.

Objective

To assess overall antibiotic resistance profiles and trends among bacterial isolates from ocular sources collected during 10 years.

Design, Setting, and Participants

This cross-sectional study of longitudinal data from the ongoing, nationwide, prospective, laboratory-based surveillance study, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study, included clinically relevant isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae cultured from patients with ocular infections at US centers from January 1, 2009, to December 31, 2018.

Main Outcomes and Measures

Minimum inhibitory concentrations were determined for various combinations of antibiotics and species. Odds ratios (ORs) were determined for concurrent antibiotic resistance; analysis of variance and χ² tests were used to evaluate resistance rates by patient age and geographic region; Cochran-Armitage tests identified changing antibiotic susceptibility trends over time.

Results

A total of 6091 isolates (2189 S aureus, 1765 CoNS, 590 S pneumoniae, 767 P aeruginosa, and 780 H influenzae) from 6091 patients were submitted by 88 sites. Overall, 765 S aureus (34.9%) and 871 CoNS (49.3%) isolates were methicillin resistant and more likely to be concurrently resistant to macrolides (azithromycin: S aureus: OR, 18.34 [95% CI, 13.64-24.67]; CoNS: OR, 4.59 [95% CI, 3.72-5.66]), fluoroquinolones (ciprofloxacin: S aureus: OR, 22.61 [95% CI, 17.96-28.47]; CoNS: OR, 9.73 [95% CI, 7.63-12.40]), and aminoglycosides (tobramycin: S aureus: OR, 18.29 [95% CI, 13.21-25.32]; CoNS: OR, 6.28 [95% CI, 4.61-8.56]) compared with methicillin-susceptible isolates (P < .001 for all). Multidrug resistance was observed among methicillin-resistant S aureus (577 [75.4%]) and CoNS (642 [73.7%]) isolates. Antibiotic resistance among S pneumoniae isolates was highest for azithromycin (214 [36.3%]), whereas P aeruginosa and H influenzae isolates showed low resistance overall. Differences in antibiotic resistance were found among isolates by patient age (S aureus: F = 28.07, P < .001; CoNS: F = 11.46, P < .001) and geographic region (S aureus: F = 8.03, P < .001; CoNS: F = 4.79, P = .003; S pneumoniae: F = 8.14, P < .001; P aeruginosa: F = 4.32, P = .005). Small changes in antibiotic resistance were noted over time (≤2.5% per year), with decreases in resistance to oxacillin/methicillin (oxacillin: −2.16%; 95% CI, −3.91% to −0.41%; P < .001) and other antibiotics among S aureus isolates, a decrease in ciprofloxacin resistance among CoNS (−1.38%; 95% CI, −2.24% to −0.52%; P < .001), and an increase in tobramycin resistance among CoNS (0.71%; 95% CI, –0.29% to 1.71%; P = .03). Besifloxacin retained consistently low minimum inhibitory concentrations.

Conclusions and Relevance

Antibiotic resistance may be prevalent among staphylococcal isolates, particularly among older patients. In this study, a few small differences in antibiotic resistance were observed by geographic region or longitudinally.

S. aureus Infections in Chicago, 2006-2014: Increase in CA MSSA and Decrease in MRSA Incidence

OBJECTIVE To examine trends in Staphylococcus aureus infections in adults and children at a single academic center in 2006-2014. DESIGN Retrospective cohort study. SETTING Inpatient, outpatient, and emergency department settings in a private, tertiary referral center. PATIENTS Patients with an infection culture that grew S. aureus in January 1, 2006, through March 31, 2014. METHODS The first isolate per year for each patient was classified as community-associated (CA-), healthcare-associated (HA-), or HA-community-onset S. aureus. The incidence density of S. aureus, methicillin-susceptible S. aureus (MSSA), and methicillin-resistant S. aureus (MRSA) infections were calculated per quarter year. RESULTS Overall, 5,491 MRSA and 5,398 MSSA isolates were included. MRSA infections decreased by an average of 5.2% annually (P<.001). MRSA skin and soft-tissue infection (SSTI) incidence density decreased in adults (-3.5%; P<.001) and children (-2.9%; P=.004). MSSA infections at all anatomic sites increased by an average of 1.9% annually (P=.007) in adults and decreased 5.1% annually (P<.001) in children. MSSA SSTI incidence density increased in adults (+3.8%; P<.001) and children (+5.6%; P<.001). For MRSA and MSSA SSTI isolates, susceptibility to tetracycline and clindamycin decreased significantly. CONCLUSIONS In 2006-2014, MRSA SSTI incidence decreased among children and adults. MSSA SSTI incidence density increased in children and adults, suggesting that current empiric SSTI treatment recommendations may not be optimal. Adults experienced an overall increase in MSSA infections, which may prompt consideration of the need for horizontal infection control practices to decrease MSSA infection risk. Infect Control Hosp Epidemiol 2017;38:1226-1234.

Evaluation of multiple real-time PCR tests on nasal samples in a large MRSA surveillance program

OBJECTIVES

We evaluated the LightCycler MRSA Advanced Test (Roche Molecular Diagnostics, Pleasanton, CA), the BD MAX MRSA assay (Becton Dickinson, Franklin Lakes, NJ), and the Xpert MRSA assay (Cepheid, Sunnyvale, CA) on nasal samples using the same population.

METHODS

Admission and discharge nasal swabs were collected from inpatients using a double-headed swab. One swab was plated onto CHROMagar MRSA (CMA; Becton Dickinson, Sparks, MD) and then broken off into tryptic soy broth (TSB) for enrichment. TSB was incubated for 24 hours and then plated to CMA. The molecular tests were performed on the second swab. We analyzed the cost benefit of testing to evaluate what parameters affect hospital resources.

RESULTS

A total of 27,647 specimens were enrolled. The sensitivity/specificity was 98.3%/98.9% for the LightCycler MRSA Advanced Test and 95.7%/98.8% for the Xpert MRSA assay, but the difference was not significant. The positive predictive value was 86.7% for the LightCycler MRSA Advanced Test, 82.7% for the Xpert MRSA assay (P > .1), and 72.2% and for the BD MAX MRSA test (P < .001 compared with the LightCycler MRSA Advanced Test). All three assays were cost-effective, with the LightCycler MRSA Advanced Test having the highest economic return.

CONCLUSIONS

Our results suggest that the performance of the three commercial assays is similar. When assessing economic cost benefit of methicillin-resistant Staphylococcus aureus screening, the two measures with the most impact are the cost of the test and the specificity of the assay results.

Antibiotic Resistance Profiling of Staphylococcus aureus Isolated from Clinical Specimens in a Tertiary Hospital from 2010 to 2012

MRSA infection can affect a wide array of individuals that may lead to treatment failure. Also, the infection has the potential to spread from one area to another particularly health care facilities or communities eventually causing minor outbreaks. With this premise, the study aimed to describe MRSA infections using the hospital-based data of a tertiary hospital in Bacolod City, Philippines, from 2010 to 2012. Specifically, this study aimed to evaluate the antimicrobial resistance of S. aureus isolated from clinical specimens and to put emphasis on the prevalence of MRSA and Inducible Clindamycin Resistance. A total of 94 cases from 2010 to 2012 were diagnosed to have S. aureus infection using conventional bacteriologic methods. From these cases, 38 (40.6%) were identified as MRSA and 37 (39.4%) were inducible clindamycin resistant. Wounds and abscesses were considered to be the most common specimens with MRSA infections having 71.05% while blood was the least with 5.3%. For drug susceptibility, out of the 94 S. aureus cases, including MRSA, 100% were susceptible to linezolid making it the drug of choice for this study. It was then followed by tetracycline having a mean susceptibility of 95%;, while penicillin G was ineffective with 94 cases having 0% susceptibility.

"Step up for foot care": addressing podiatric care needs in a sample homeless population

BACKGROUND

Studies have shown that lower-extremity problems in the homeless population have significant public health and economic implications. A combined community service and research project was performed to identify and address the foot and ankle care needs in a sample homeless population in San Francisco, California.

METHODS

A 37-question survey regarding general demographic characteristics, foot hygiene practices, associated risk factors, and self-reported lower-extremity pathologic conditions was completed by 299 homeless individuals who met the inclusion criteria. The service project included education on proper foot care and the distribution of footwear.

RESULTS

The participants demonstrated mostly good efforts regarding foot hygiene but had high-risk factors, including smoking, alcohol use, and extended hours on their feet. More than half of the homeless individuals surveyed experienced foot pain. Approximately one in five had edema and neuropathic symptoms. The most commonly reported foot problems were dermatologic, but these conditions could pose serious sequelae in the setting of risk factors. The community service project was well received by the homeless community.

CONCLUSIONS

This study demonstrates lack of resources and high-risk factors for lower-extremity complications in the homeless individuals studied. It is important in the realm of public health to keep lower-extremity health in mind because it plays an important role in preventing the spread of infection and lowering the social economic burden.

Nasal Carriage of Epidemic Methicillin-Resistant Staphylococcus aureus 15 (EMRSA-15) Clone Observed in Three Chicago-Area Long-Term Care Facilities

The spread of pandemic methicillin-resistant Staphylococcus aureus (MRSA) clones such as USA300 and EMRSA-15 is a global health concern. As a part of a surveillance study of three long-term care facilities in the Greater Chicago area, phenotypic and molecular characterization of nasal MRSA isolates was performed. We report a cluster of pandemic EMRSA-15, an MRSA clone rarely reported from the United States, detected during this study.

Podiatric health needs of homeless populations as a public health concern

BACKGROUND

Foot and ankle health among the homeless is an important public health concern. There are limited studies done thus far on foot and ankle conditions and the podiatric medical needs of homeless populations. A literature review was undertaken to evaluate any studies published about the lower-extremity health needs among the homeless.

METHODS

We did a literature search through PubMed, the US National Library of Medicine's database of biomedical citations and abstracts for relevant publications from 1988 through 2008. We also searched the references cited in the articles found for any studies relevant to podiatric needs for homeless populations.

RESULTS

We found three relevant articles that addressed the needs of podiatric care for the homeless. The articles highlighted the community health importance of foot care for homeless populations, especially in helping prevent potentially limb-threatening pathologies.

CONCLUSIONS

The small number of studies published so far all emphasize the major public health need for podiatric care among homeless populations. More studies are needed to help address this important public health concern.

Community acquired infections in older patients admitted to hospital from care homes versus the community: cohort study of microbiology and outcomes

BACKGROUND

Residents of care homes are at risk of colonisation and infection with antibiotic resistant bacteria, but there is little evidence that antibiotic resistance among such patients is associated with worse outcomes than among older people living in their own homes. Our aim was to compare the prevalence of antibiotic resistant bacteria and clinical outcomes in older patients admitted to hospital with acute infections from care homes versus their own homes.

METHODS

We enrolled patients admitted to Ninewells Hospital in 2005 who were older than 64 years with onset of acute community acquired respiratory tract, urinary tract or skin and soft tissue infections, and with at least one sample sent for culture. The primary outcome was 30 day mortality, adjusted for age, sex, Charlson Index of co-morbidity, sepsis severity, presence of resistant isolates and resistance to initial therapy.

RESULTS

161 patients were identified, 60 from care homes and 101 from the community. Care home patients were older, had more co-morbidities, and higher rates of resistant bacteria, including MRSA and Gram negative organisms resistant to co-amoxiclav, cefuroxime and/or ciprofloxacin, overall (70% versus 36%, p = 0.026). 30 day mortality was high in both groups (30% in care home patients and 24% in comparators). In multivariate logistic regression we found that place of residence did not predict 30 day mortality (adjusted odds ratio (OR) for own home versus care home 1.01, 95% CI 0.40-2.52, p = 0.984). Only having severe sepsis predicted 30 day mortality (OR 10.09, 95% CI 3.37-30.19, p < 0.001), after adjustment for age, sex, co-morbidity, presence of resistant bacteria, resistance to initial therapy, and place of residence.

CONCLUSIONS

Older patients admitted with acute infection had high 30 day mortality. Patients from care homes were more likely to have resistant organisms but high levels of antimicrobial resistance were found in both groups. Thus, we recommend that antibiotic therapies active against resistant organisms, guided by local resistance patterns, should be considered for all older patients admitted with severe sepsis regardless of their place of residence.

Molecular laboratory tests for the diagnosis of respiratory tract infection due to Staphylococcus aureus

When Staphylococcus aureus is the cause of ventilator-associated pneumonia or a bacterial infection following influenza, the infections are devastating if not treated promptly. Disease due to methicillin-resistant S. aureus (MRSA) continues to be of concern throughout most of the United States. Currently, the U.S. Food and Drug Administration (FDA) has cleared polymerase chain reaction tests for detection of MRSA in nasal swab specimens; however, there are no FDA-cleared tests for identifying S. aureus in purulent respiratory secretions. The real-time polymerase chain reaction tests for S. aureus (primarily MRSA) in nares provide results in <2 h and have sensitivities ranging from 95% to 100%, with specificities of 96%-99%; these results are comparable to that of standard cultures, which can take up to 3-4 days for final results. The FDA is encouraged to work closely with industry providers to expedite the evaluation and clearance process for molecular diagnostic devices detecting S. aureus (including MRSA) in the diagnosis of respiratory tract infection.

Performance of the BD GeneOhm MRSA achromopeptidase assay for real-time PCR detection of methicillin-resistant Staphylococcus aureus in nasal specimens

We evaluated the BD GeneOhm MRSA achromopeptidase (ACP) assay, which incorporates a new specimen preparation approach. A total of 1,216 leftover nasal samples were tested; using culture as the gold standard, the sensitivity and specificity were 92% and 94.6%, respectively. The new lysis method provides good sensitivity and simplifies specimen preparation.

Increasing role of Staphylococcus aureus and community-acquired methicillin-resistant Staphylococcus aureus infections in the United States: a 10-year trend of replacement and expansion

BACKGROUND

There is the need to properly characterize the temporal trend of U.S. Staphylococcus aureus infections, including methicillin-resistant S. aureus (MRSA) and community-acquired (CA) MRSA in inpatient and outpatient settings.

METHODS

The study used the Surveillance Network(®) surveillance database (Eurofins Medinet) and the National Hospitalization Discharge Survey for the period 1998-2007. CA-MRSA phenotype was defined by a resistance profile that includes susceptibility to gentamicin and cotrimoxazole, and coresistance to ciprofloxacin/clindamycin. Adjusted rates, rate ratios, and 95% confidence intervals (CIs) were computed using multivariate logistic regression.

RESULTS

The study consisted of 1,761,991 S. aureus isolates. Annual MRSA prevalence continuously increased over the 10-year period from 32.7% in 1998 to 53.8% in 2007 (odds ratio 2.4, 95% CI 2.3-2.5). CA-MRSA replaced competing strains by increasing its share of MRSA from 22.3% in 1998 to 66.1% in 2007 (odds ratio 6.7, 95% CI 6.5-6.9). MRSA-related hospitalization rate per 1,000 discharges doubled from 3.5 ± 0.9 in 1998 to 7.6 ± 1.5 in 2007 (RR 2.2, 95% CI 1.8-3.1), whereas CA-MRSA increased from 0.4 ± 0.14 hospitalizations per 1,000 discharges in 1998 to 3.1 ± 0.5 in 2007 (RR 8.1, 95% CI 5.2-14.1), By 2007, 81.5% of all MRSA isolates were categorized as CA-MRSA among children, whereas CA-MRSA represented 48.9% of MRSA isolates from the elderly.

CONCLUSION

MRSA not only replaced methicillin susceptible S. aureus (MSSA) isolates as a percentage of all S. aureus isolates, but its hospitalization rates increased over and above the replacement process. This trend also applies to CA-MRSA over hospital-acquired (HA) MRSA.

Methicillin-resistant staphylococcus aureus screening and eradication in the surgical intensive care unit: Is it worth it?

BACKGROUND

The problem of intensive care unit methicillin-resistant Staphylococcus aureus (MRSA) infections has led to routine surveillance and eradication strategies.

METHODS

Our surgical intensive care unit (SICU) admissions receive MRSA nares cultures and if positive are isolated followed by eradication treatment. This strategy was retrospectively reviewed.

RESULTS

Our nares-positive culture rate was 21% (30/145), and the sputum positive (sputum+) rate was 18% (26/145). Positive nares culture (Nares+) was eradicated in 63%. The rate of sputum+ in Nares+ patients was 36% (9/25). The rate of sputum+ in Nares- was 10% (12/115; P = .003). The sputum+ SICU length of stay (LOS) (18 ± 12 days in 23 S+ patients) is longer than in sputum- (10 ± 9 days in 69 S-patients, P = .0002).

CONCLUSIONS

This SICU has high rates of both nares and sputum MRSA cultures. Our data suggest eradicating nares colonization may prevent pneumonia and might decrease SICU LOS.

To screen or not to screen for methicillin-resistant Staphylococcus aureus

There are few more compelling questions in clinical microbiology today than the issue of whether or not to screen for the presence of methicillin-resistant Staphylococcus aureus (MRSA), with the results being used to institute infection control interventions aimed at preventing transmission of MRSA in health care environments. Numerous different matters must be addressed when considering a screening program. Who is to be screened, what method is to be employed to detect MRSA, and what sites should be sampled? When and how often should the screening be performed? Who is going to pay for the screening, and, finally and perhaps most importantly, how are screening results to be communicated to health care providers and what kind of interventions are best undertaken based on the results? Numerous governmental agencies have mandated MRSA screening programs, and yet several authorities in infection control organizations have questioned the appropriateness of mandated screening. In this Point-Counterpoint feature, Dr. Lance Peterson of Evanston Hospital (Evanston, IL) offers his perspective on why screening for MRSA is to be encouraged. Dr. Daniel Diekema of the University of Iowa Carver College of Medicine (Iowa City, IA) offers an opposing view.