Significance of MRSA strains in community associated skin and soft tissue infections

Detection of Methicillin Resistance and β-Lactamase Production in Staphylococcus aureus Isolates: A Cross Sectional Study from a Tertiary Care Hospital

Nosocomial infections are proving to be a menace for the whole health care system, with methicillin resistant Staphylococcus aureus (MRSA) being a very notorious causative agent. Along with the role of mecA gene producing penicillin-binding protein (PBP2a), production of beta-lactamase enzyme by Staphylococcus aureus makes the organism resistant to all β-lactam agents. This study aims at phenotypic detection of methicillin resistance and β-Lactamase production in all S. aureus isolates by Cefoxitin disk diffusion test and Penicillin zone-edge test, respectively. In this prospective cross-sectional study, samples were obtained from patients admitted to different departments and were processed according to the standard laboratory protocols. As per the CLSI guidelines, phenotypic detection of resistance to methicillin was done by Cefoxitin Disk Diffusion test, whereas production of beta-lactamase enzyme was phenotypically detected by penicillin zone edge test. Among 179 isolates of S. aureus, 116 (64.8%) were MRSA, whereas the remaining 63 (35.2%) isolates were methicillin-sensitive Staphylococcus aureus (MSSA). Staphylococcus aureus infection among ICU and non-ICU patients were found to be 24(13%) and 155(86.6%) respectively. Among 24 ICU patients, 19 had MRSA infection, whereas among 155 non-ICU patients, 97 had MRSA infection. Out of 63 MSSA isolates, only 2 (3.17%) were found to be sensitive to Penicillin by Zone-edge test, 04 isolates showed presence of β-lactamase production, while remaining 57 isolates were resistant to Penicillin. At the same time, several class of antibiotics were found to be ineffective against these MRSA isolates. Cases of methicillin-resistant and b–lactamase producing Staphylococcus aureus infections are on the rise in our hospital settings.

Prevalence and Characterization of Methicillin-Resistant Staphylococcus aureus from Community- and Hospital-Associated Infections: A Tertiary Care Center Study

The community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become increasingly prevalent in both community and hospital settings. The aim of this study was to determine the prevalence, molecular characteristics and antibiotic resistance profiles of CA-MRSA from community- and hospital-associated infections in a tertiary care hospital in Mangalore, India. Of 520 S. aureus isolates, 362 were from inpatients (IP) and 158 were from outpatients (OP). One-hundred and thirty-two MRSA isolates obtained from 94 inpatients and 38 outpatients with complete clinical details were further analyzed. Of these, 81 (61.4%) were CA-MRSA (IP-47.9%, OP-94.7%) and 51 (38.6%) were HA-MRSA (IP-52.1%, OP-5.3%). All (100%) MRSA isolates were mecA gene positive. SCCmec typing identified SCCmec type IV (50.6%) and SCCmec type V (66.7%) in CA-MRSA, while SCCmec type I (41.2%), SCCmec type III (19.6%), SCCmec type IV (31.4%) and SCCmec type V (25.5%) were detected in HA-MRSA isolates. The Panton–Valentine Leukocidin (PVL) gene was found in 70.4% of CA-MRSA, 43.1% of HA-MRSA with SCCmec type IV and SCCmec type V, and in 7.8% of true HA-MRSA. The antibiotic resistance profiles were determined by the disc diffusion method. Resistance to cefoxitin was used to identify MRSA. A significant difference (p < 0.05) was observed between CA-MRSA and HA-MRSA with respect to resistance against cephalexin, cefotaxime, levofloxacin, linezolid and teicoplanin. CA-MRSA was predominantly resistant to ciprofloxacin (86.4%), erythromycin (66.7%), ofloxacin (49.4%), cefotaxime (44.4%), gentamicin (40.7%) and clindamycin (40.7%), while HA-MRSA showed resistance against ciprofloxacin (80.4%), erythromycin (80.1%), cefotaxime (70.6%),ofloxacin (58.8%), clindamycin (47.1%) and levofloxacin (41.2%).This study reports the prevalence of CA-MRSA in community and hospital settings and the possibility of multidrug-resistant CA-MRSA replacing HA-MRSA in hospitals. The observations from our study emphasize the need for urgent measures to manage this emerging crisis in healthcare settings.

Pediatric empyema thoracis: What has changed over a decade?

OBJECTIVES

The purposes of this paper are to study clinicobacteriological profile, treatment modalities and outcome of pediatric empyema thoracis and to identify changes over a decade.

DESIGN

This is a retrospective study.

SETTING

Department of Pediatrics of a tertiary care hospital in North India.

PATIENTS

We enrolled 205 patients (1 month-12 years) of empyema thoracis admitted over 5 years (2007-11) and compared the profile with that of a previous study from our institute (1989-98).

RESULTS

Pleural fluid cultures were positive in 40% (n = 82) cases from whom 87 isolates were obtained. Staphylococcus aureus was the most common isolate (66.7%). Methicillin-sensitive S. aureus accounted for 56%, Methicillin-resistant S. aureus (MRSA) 10% and gram-negative organisms 18.3% of isolates. Intercostal drainage tube (ICDT) was inserted in 97.5%, intrapleural streptokinase was administered in 33.6%, and decortication performed in 27.8% cases. Duration of hospital stay was 17.2 (±6.3) days, duration of antibiotic (intravenous and oral) administration was 23.8 (±7.2) days and mortality rate was 4%. In the index study (compared with a previous study), higher proportion of cases received parenteral antibiotics (51.7% vs. 23.4%) and ICDT insertion (20.5% vs. 7%) before referral and had disseminated disease (20.5% vs. 14%) and septic shock (11.2% vs. 1.6%), less culture positivity (40% vs. 48%), more MRSA (10.3% vs. 2.5%) and gram-negative organisms (18.4% vs. 11.6%), increased use of intrapleural streptokinase and surgical interventions (27.8% vs. 19.7%), shorter hospital stay (17 vs. 25 days) and higher mortality (3.9% vs. 1.6%).

CONCLUSIONS

Over a decade, an increase in the incidence of empyema caused by MRSA has been noticed, with increased use of intrapleural streptokinase and higher number of surgical interventions.

Antibiotic Sensitivity and Clinico- epidemiological Profile of Staphylococcal Infections

This hospital-based study describes the antibiotic sensitivity of 66 S. aureus isolates from the admitted children (age 0-18 y) in a tertiary hospital of Kolkata, India. Methicillin-resistant S. aureus constituted 16.7% (n=11) of the isolates. Clindamycin-resistance was observed in 60% and 82% of methicillin-sensitive and methicillin-resistant strains, respectively.

A study of community-associated methicillin-resistant Staphylococcus aureus in patients with pyoderma

BACKGROUND

Health care-associated methicillin-resistant Staphylococcus aureus(HA-MRSA) are resistant to multiple antibiotics, therefore infections caused by them are difficult to treat resulting in high morbidity and mortality. While most of the research activities and public health initiatives are focused on HA-MRSA, the newly emerging pathogen, community-associated methicillin-resistant Staphylococcus aureus(CA-MRSA) is gaining in significance in respect to patient morbidity. There is a significant paucity of data regarding CA-MRSA in the developing parts of the world.

AIM

To study the proportions of HA-MRSA and CA-MRSA infections among patients with culture-proven S. aureus infection and to find out how many of these patients showed presence of MRSA in nasal cultures of healthy contacts.

MATERIALS AND METHODS

Clinical details of 227 patients were recorded in the study, such as the duration and recurrence of the infection, history of antibiotic intake, and the presence of other medical illnesses. A pus swab was taken from each lesion and sent for culture and sensitivity. If the culture grew S. aureus, they were screened for methicillin resistance. A swab from the anterior nares of the healthy contact of each patient, whenever available, was collected and it was screened for MRSA.

RESULTS

Furunculosis was most common among the primary pyodermas (53/134; 39. 5%). Out of 239 pus culture samples obtained from 227 patients, 192 (84.58%) grew S. aureus; of these 150 (78.12%) were methicillin-sensitive S. aureus (MSSA), whereas 42 (21.98%) were MRSA. Out of the 42 MRSA isolated, 33 turned out to be CA-MRSA (78%) and 9 (22%) were HA-MRSA. Nasal swabs of healthy contacts of 34 MRSA patients were cultured. Out of them, two grew MRSA in the culture.

CONCLUSION

The isolation rate of S. aureus was high in our study. Furthermore, our study, although hospital based, clearly indicated the substantial magnitude of the CA-MRSA problem in the local population.

Antimicrobial resistance in India: A review

Antimicrobial resistance is an important concern for the public health authorities at global level. However, in developing countries like India, recent hospital and some community based data showed increase in burden of antimicrobial resistance. Research related to antimicrobial use, determinants and development of antimicrobial resistance, regional variation and interventional strategies according to the existing health care situation in each country is a big challenge. This paper discusses the situational analysis of antimicrobial resistance with respect to its problem, determinants and challenges ahead with strategies required in future to reduce the burden in India. Recent data from Google search, Medline and other sources were collected which was reviewed and analyzed by the authors. Hospital based studies showed higher and varied spectrum of resistance in different regions while there are limited number of community based studies at country level. There exists lacunae in the structure and functioning of public health care delivery system with regard to quantification of the problem and various determining factors related to antimicrobial resistance. There is an urgent need to develop and strengthen antimicrobial policy, standard treatment guidelines, national plan for containment of AMR and research related to public health aspects of AMR at community and hospital level in India.

Changing Trends in Resistance Pattern of Methicillin Resistant Staphylococcus aureus

BACKGROUND

Methicillin resistance in Staphylococcus aureus is associated with multidrug resistance, an aggressive course, increased mortality and morbidity in both community and health care facilities. Monitoring of newly emerging and prevalent Methicillin Resistant Staphylococcus aureus (MRSA) strains for their resistance patterns to conventional as well as novel drugs, are essential for infection control.

AIMS

To study the changing trends in resistance patterns of MRSA at our hospital.

SETTINGS AND DESIGN

This cross sectional study was carried out in a 750 bed tertiary care hospital in south India.

MATERIAL AND METHODS

One hundred and two clinical isolates of MRSA which were obtained in 2004-2011 were identified by using oxacillin, cefoxitin disc diffusion test and oxacillin screening agar test. Antibiotic susceptibility test was done for commonly used non beta lactam anti-Staphylococcal drugs, as well as for anti-MRSA drugs like vancomycin, linezolid, mupirocin and rifampicin. Minimum inhibitory concentration (MIC) of vancomycin was determined by using Vancomycin HiComb strip (Himedia, Mumbai, India). Statistical Analysis which was done: Chi-square test and proportions were used to compare the two groups.

RESULTS

MRSA isolates showed high resistance to co-trimoxazole (82.3%), ciprofloxacin (76.4%), gentamicin (64.7%) and tetracycline (49%) as compared to other drugs. High prevalence of ciprofloxacin resistance was detected, particularly among outpatients. Multi resistant MRSA with a ≥ 3 non-beta lactam agent resistance was 79%. All MRSA isolates were sensitive to vancomycin, linezolid, mupirocin and rifampicin. MRSA had displayed increase in resistance to most antibiotics except tetracycline in recent years.

CONCLUSIONS

Taking into consideration the prevalence of multidrug resistance in MRSA, resistance patterns should be evaluated periodically and antibiotic therapy should be guided by susceptibility testing.

Changes in prescriptive practices in skin and soft tissue infections associated with the increased occurrence of community acquired methicillin resistant Staphylococcus aureus

BACKGROUND

Over 30% of the US population is colonized with methicillin resistant Staphylococcus aureus (MRSA). People within the community, without factors associated with Hospital Acquired (HA) MRSA, present with skin and soft tissue infections (SSTIs). Community Acquired MRSA (CA-MRSA) is resistant to antibiotics typically prescribed for SSTI. Many SSTIs are treated with antibiotics that are ineffective against drug resistant strains.

STUDY OBJECTIVES

This study examines the incidence of SSTIs associated with CA-MRSA, to determine if an increase in SSTI's is associated with changes in prescribing patterns for MRSA.

METHODS

A secondary analysis of the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) data was used to detect incidence of SSTIs based on ICD-9 coding between the periods of 1997-2002 and 2003-2008. Antibiotic prescribing patterns were examined for treatment.

RESULTS

Incidence of SSTIs increased by 84.7% from 1997-2002 to 2003-2008. Antibiotics prescribed for methicillin sensitive S. aureus decreased while treatment with MSRA antibiotics increased.

CONCLUSION

There is an increased incidence of SSTI within the community, suggesting that CA-MRSA may be a contributing factor. Health care providers are recognizing the increased incidence of CAMRSA, and are treating SSTI with appropriate antibiotics.

Improved antimicrobial efficacy with nitric oxide releasing nanoparticle generated S-nitrosoglutathione

Nitric oxide (NO) plays a vital role in mammalian host defense through a variety of mechanisms. In particular, NO can oxidize to form reactive nitrogen species or interact with protein thiols and metal centers, blocking essential microbial processes. S-nitrosoglutathione (GSNO), a potent NO donor formed by the interaction of NO with intracellular glutathione (GSH), is a major factor in this pathway and is considered one of the strongest naturally occurring nitrosating agent. We previously described the broad-spectrum antimicrobial activity of a nanoparticulate platform capable of controlled and sustained release of NO (NO-np). Interestingly, in vivo efficacy of the NO-np surpassed in vitro data generated. We hypothesized that the enhanced activity was in part achieved via the interaction between the generated NO and available GSH, forming GSNO. In the current study, we investigated the efficiency of NO-np to form GSNO in the presence of GSH was evaluated, and assessed the antimicrobial activity of the formed GSNO against methicillin resistant Staphylococcus aureus (MRSA), Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. When GSH was combined with NO-np, GSNO was rapidly produced and significant concentrations of GSNO were maintained for >24h. The GSNO generated was more effective compared to NO-np alone against all bacterial strains examined, with P. aeruginosa being the most sensitive and K. pneumoniae the most resistant. We conclude that the combination of NO-np with GSH is an effective means of generating GSNO, and presents a novel approach to potent antimicrobial therapy.