Multidrug-resistant Methicillin-resistant Staphylococcus Aureus Isolates Research Articles

High Prevalence of Multi-drug Resistant Methicillin-Resistant Staphylococcus aureus in Tertiary Egyptian Hospitals.

Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of morbidity and mortality worldwide. This work aimed to study the occurrence of multidrug-resistant MRSA (MDR-MRSA) in tertiary Egyptian hospitals and determine the antimicrobial susceptibilities and the genetic relatedness of isolates for epidemiological assessment. A total of 170 S. aureus isolates were collected from two Egyptian tertiary hospitals in Cairo, between September 2017 and December 2018. MRSA isolates were identified using the conventional microbiological methods and confirmed by the PCR assays targeting nuc gene, a surrogate marker of S. aureus and the mecA gene for genotypic identification of methicillin resistance. Antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method and the isolates were grouped into different antibiotypes based on their antibiograms. The genetic relatedness among MDR-MRSA isolates was determined by ERIC-PCR-based molecular typing. High prevalence of MRSA isolates was identified (138/170, 81.2%) with 79% of isolates (109/138, 79%) being MDR-MRSA. MRSA isolates were resistant to diverse classes of antimicrobials including β-lactams, aminoglycosides and macrolides. Among MRSA isolates, the highest resistance rate was to each cefoxitin and penicillin (100%) and the highest susceptibility was to linezolid (92%). Based on the antibiograms of 109 MDR-MRSA isolates, 52 antibiotypes were determined, and 46 different ERIC fingerprints were identified among MDR-MRSA antibiotypes. MRSA infections remain a noteworthy problem in Egyptian hospitals. MDR-MRSA isolates showed significant genetic diversity indicating the alarmingly high prevalence. Studies should be performed frequently, even in each healthcare setting, to determine the epidemiology of MRSA isolates and their antimicrobial susceptibility profiles for effective control measures of MRSA infections and better healthcare management.

Methicillin-resistant staphylococci among school children in Mariental, Namibia

Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to beta-lactam antibiotics, while some strains are multi-drug resistant and may produce disease-causing toxins. Drug resistant strains are often responsible for chronic, persistent and recurrent infections, which pose a challenge for healthcare practitioners. Our study aimed to determine the prevalence of nasal MRSA and methicillin-resistant coagulase-negative staphylococci (MRCoNS) among school children in the Mariental community, southern Namibia. This was a cross-sectional study in the Mariental District. Nasal specimens (swabs) were collected from 272 randomly selected learners aged 6–14 years attending school in the area during the months of March, September and October 2016. Isolation and identification of staphylococci were performed using standard microbiological methods. Methicillin-resistant isolates were identified by their resistance towards cefoxitin (30 µg) using the Kirby-Bauer disk diffusion assay. Enterotoxin production among multi-drug resistant MRSA isolates was detected with a SET-RPLA toxin detection kit. Methicillin-resistant S. aureus was isolated from 48 (17.6%) learners and MRCoNS from only seven (2.6%). Methicillin-resistant S. aureus colonization was significantly higher (P = 0.003) in the age group 11–14 years than in the group 6–10 years. Among the 433 staphylococcal isolates screened for cefoxitin resistance, 51 (11.8%) were MRSA and seven (1.6%) were MRCoNS. From the 51 MRSA isolates, 22 (43.1%) were multi-drug resistant of which six were enterotoxigenic. This is the first report on MRSA and MRCoNS among school children in Namibia. The presence of multi-drug resistant and potentially virulent staphylococci among school children in Mariental, Namibia, is of concern. Self-infection by these bacteria poses various health risks for the children. It is recommended that school health programmes improve current hygiene practices. Frequent handwashing can prevent staphylococcal disease and spread of resistant strains among learners and the wider community.

Molecular and Anti-Microbial Resistance (AMR) Profiling of Methicillin-Resistant Staphylococcus aureus (MRSA) from Hospital and Long-Term Care Facilities (LTCF) Environment.

To provide evidence of the cross-contamination of emerging pathogenic microbes in a local network between long-term care facilities (LTCFs) and hospitals, this study emphasizes the molecular typing, the prevalence of virulence genes, and the antibiotic resistance pattern of methicillin-resistant Staphylococcus aureus. MRSA isolates were characterized from 246 samples collected from LTCFs, medical tubes of LTCF residents, and hospital environments of two cities, Chiayi and Changhua. Species identification, molecular characterization, and drug resistance analysis were performed. Hospital environments had a higher MRSA detection rate than that of LTCF environments, where moist samples are a hotspot of MRSA habitats, including tube samples from LTCF residents. All MRSA isolates in this study carried the exfoliative toxin eta gene (100%). The majority of MRSA isolates were resistant to erythromycin (76.7%), gentamicin (60%), and ciprofloxacin (55%). The percentage of multidrug-resistant MRSA isolates was approximately 50%. The enterobacterial repetitive intergenic consensus polymerase chain reaction results showed that 18 MRSA isolates belonged to a specific cluster. This implied that genetically similar isolates were spread between hospitals and LTCFs in Changhua city. This study highlights the threat to the health of LTCFs’ residents posed by hospital contact with MRSA.

Characterization of Antibiotic Resistance and Virulence Traits Present in Clinical Methicillin-Resistant Staphylococcus aureus Isolates.

Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious superbug which poses serious health threats to humanity. The severity of the infections depends on the prevalence of virulence factors and antibiotic resistance. In this study, attempts have been made to nominate the two most virulent and multidrug-resistant MRSA isolates demonstrating the preliminary features of intestinal adhesion for the futuristic applications of probiotics and postbiotics as antagonists to combat MRSA infections. In this context, six clinical isolates of MRSA were polyphasically characterized for their identity, multidrug resistance, and few selected virulence determinates such as hemolytic activity and production of coagulase, nuclease, and capsule. The gut colonizing ability of MRSA isolates was assessed by mucoadhesion, auto-aggregation, and cell surface hydrophobicity. An antibiogram of MRSA isolates suggested the resistance towards several antibiotics with multiple antibiotic resistance (MAR) index >0.5 (12/241, 12/206, and 5/255) as well as their genome portraying mecA mediated methicillin resistance. Besides exhibiting strong biofilm formation ability, all the isolates exhibited positive responses towards tested virulence assays coupled with their genome displaying Coa, NucA, and CapE genes. On the other hand, isolates exhibited different levels of auto-aggregation (37.90 ± 1.8 to 51.53 ± 3.1%) and mucin adhesion ability (68.93 ± 0.61% to 86.62 ± 1.96%) with a significant (P ≤ 0.05) variation in adhesion to different hydrocarbons. Finally, multivariate Principal Component Analysis and Hierarchical Cluster Analysis (HCA) heatmap using Euclidean distance measurement indicated MRSA 12/206 and 5/255 as most resistant and virulent isolates with the potential to adhere to the hydrophobic gut niche.

Promising Antibiofilm Agents: Recent Breakthrough against Biofilm Producing Methicillin-Resistant Staphylococcus aureus

Multidrug resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) is a superbug pathogen that causes serious diseases. One of the main reasons for the lack of the effectiveness of antibiotic therapy against infections caused by this resistant pathogen is the recalcitrant nature of MRSA biofilms, which results in an increasingly serious situation worldwide. Consequently, the development of innovative biofilm inhibitors is urgently needed to control the biofilm formation by this pathogen. In this work, we thus sought to evaluate the biofilm inhibiting ability of some promising antibiofilm agents such as zinc oxide nanoparticles (Zno NPs), proteinase K, and hamamelitannin (HAM) in managing the MRSA biofilms. Different phenotypic and genotypic methods were used to identify the biofilm producing MDR MRSA isolates and the antibiofilm/antimicrobial activities of the used promising agents. Our study demonstrated strong antibiofilm activities of ZnO NPs, proteinase K, and HAM against MRSA biofilms along with their transcriptional modulation of biofilm (intercellular adhesion A, icaA) and quorum sensing (QS) (agr) genes. Interestingly, only ZnO NPs showed a powerful antimicrobial activity against this pathogen. Collectively, we observed overall positive correlations between the biofilm production and the antimicrobial resistance/agr genotypes II and IV. Meanwhile, there was no significant correlation between the toxin genes and the biofilm production. The ZnO NPs were recommended to be used alone as potent antimicrobial and antibiofilm agents against MDR MRSA and their biofilm-associated diseases. On the other hand, proteinase-K and HAM can be co-administrated with other antimicrobial agents to manage such types of infections.

Antibacterial and anti-quorum sensing activities of a substituted thiazole derivative against methicillin-resistant Staphylococcus aureus and other multidrug-resistant bacteria

Management of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) is still challenging. We herein report the antibacterial and anti-quorum sensing (anti-QS) activities of 5-acetyl-4-methyl-2-(3-pyridyl) thiazole (AMPT) against MRSA and other multidrug-resistant bacteria. Minimum inhibitory concentrations (MICs) were determined by agar dilution method and bactericidal activity was assessed by a time-kill assay. The anti-QS activity was evaluated using Chromobacterium violaceum. The effect of AMPT on virulence factors production by MRSA and biofilm formation by MRSA, C. violaceum and Pseudomonas aeruginosa was also assessed. AMPT was superior to vancomycin and teichoplanin against MRSA isolates. MIC50/90 values of AMPT (2/4 mg/L) were 2–4 folds lower than the values for vancomycin (4/16 mg/L) and 2-fold lower than the values for teichoplanin (4/8 mg/L). Results of time-kill assay against two multidrug-resistant MRSA isolates revealed bactericidal effect of AMPT after 4 h of treatment, with no bacterial cells detected after 24 h. Remarkably, AMPT exhibited anti-QS activity against both C. violaceum and MRSA at subinhibitory concentrations. Moreover, AMPT reduced haemolysin and protease production by MRSA and inhibited biofilm formation by MRSA, C. violaceum and P. aeruginosa but had no dispersion effect on preformed ones. Furthermore, molecular docking analysis revealed promising interactions between AMPT and AgrA as well as SarA in S. aureus confirming the antivirulence and antibiofilm activities. Favourably, no significant cytotoxicity of AMPT was observed on murine macrophage cell line. Taken altogether, these results suggest that AMPT could be considered an interesting lead compound in the search for treatment of MRSA infections.

Multidrug-resistance in methicillin-resistant Staphylococcus aureus (MRSA) isolated from a subtropical river contaminated by nearby livestock industries.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major threat to public health that causes infections in hospitals, communities, and animal husbandry. Livestock-associated MRSA (LA-MRSA) is defined as MRSA possessing staphylococcal cassette chromosome mec (SCCmec) IV or V, both of which lacks the Panton-Valentine leukocidin (PVL) gene but has variable combinations of antimicrobial susceptibility. This study focused on Taiwan's subtropical river basin and the Puzih River, which converges from tributaries flowing through downtown and animal husbandry areas. MRSA was detected at a rate of 7.8% in the tributaries, which was higher than downstream (2.1%). The ratio of multidrug-resistant (MDR) MRSA (n=30) to total MRSA isolates (n=39) was 0.769, and most of the MDR MRSA isolates (66.7%, 20/30) exhibited resistance to chloramphenicol, ciprofloxacin, clindamycin, erythromycin, sulfamethoxazole-trimethoprim, and tetracycline. The number of MDR MRSA isolates in the tributaries was also higher than the downstream regions of the Puzih River. The majority of MRSA isolates (64.1%) observed in this study possessed SCCmec type IV without PVL, which is typical for LA-MRSA. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) typing aided the discrimination of resistance patterns among SCCmec types. This study highlights the threat to human health posed by the waterborne transmission of MDR LA-MRSA.

Draft genome sequence of Staphylococcus agnetis 3682, the producing strain of the broad-spectrum lantibiotic agneticin 3682.

Here we report the draft genome sequence of Staphylococcus agnetis 3682, a strain producing agneticin 3682, a broad-spectrum lantibiotic with potential medical applications. The inhibitory activity of S. agnetis 3682 against multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolates involved in human infections was also investigated. A sequencing library was constructed using a Nextera XT DNA Library Preparation Kit. An Illumina MiSeq system was used to perform whole-genome shotgun sequencing. De novo genome assembly was performed using the A5-miseq pipeline. Staphylococcus agnetis 3628 genome annotation was performed by the RAST server, and BAGEL4 and antiSMASH v.4.0 platforms were used for mining bacteriocin gene clusters. The inhibitory activity of S. agnetis 3682 against 20 multidrug-resistant MRSA strains involved in human infections in two Brazilian hospitals was determined by the deferred antagonism assay on brain-heart infusion (BHI) agar plates. The total scaffold size was determined to be 2 502 817bp with a G+C content of 35.6%. Genome analyses revealed 2437 coding sequences, 76 RNA genes, 27 genes involved in drug resistance and 2 bacteriocinogenic gene clusters (for agneticin 3682 and hyicin 4244). Staphylococcus agnetis 3682 inhibited 80% of the MRSA isolates tested. This study describes the main features of the draft genome of S. agnetis 3682, a strain producing the first bacteriocin (agneticin 3682) reported in this species. A second gene cluster encoding a sactipeptide was also found in the bacterial chromosome. Agneticin 3682 shows a new potential application against clinical MRSA isolates.

Antimicrobial Resistance Patterns in Methicillin-Resistant Staphylococcus aureus from Patients Hospitalized during 2015–2017 in Hospitals in Poland

Objective: The aim of this study was to determine antimicrobial resistance profiles of methicillin-resistant Staphylococcus aureus (MRSA) isolates from clinical samples from patients hospitalized during 2015–2017 in hospitals of ­Masovian district in Poland. Materials and Methods: Antimicrobial resistance of 112 MRSA isolates was tested with a disc diffusion method. Isolates were examined for methicillin resistance using a 30 µg cefoxitin disk. Resistance was confirmed by PCR detection of the mecA gene. PCR was also used to determine spa gene polymorphism in X-region. Results: A large number of MRSA isolates showed resistance to levofloxacin (83.9%), ciprofloxacin (83%), erythromycin (77.7%) and clindamycin (72.3%). A lower number of MRSA isolates showed resistance to tetracycline (10.7%), amikacin (14.2%), gentamicin and trimethoprim with sulfamethoxazole (8.0%). None of the MRSA isolates were resistant to linezolid and teicoplanin. Among MRSA isolates, 92.9% were multidrug-resistant (MDR). Resistance to erythromycin, clindamycin, ciprofloxacin and levofloxacin was the most common resistance pattern among MDR MRSA isolates. The highest number of isolates was resistant to 4 groups of antimicrobials (53.8%). The number of drugs to which MRSA isolates were resistant in 2017 was significantly higher than that in 2016 (p = 0.002). The size polymorphism analysis of X fragment of the spa gene revealed high genetic diversity of the investigated group MRSA isolates. Conclusion: This study demonstrates that in the hospital environment, MRSA isolates can quickly acquire new antimicrobial resistance determinants and that knowledge of current resistance patterns is important for the effective treatment of infections caused by MDR MRSA.

Novel SCCmec type XII methicillin-resistant Staphylococcus aureus isolates identified from a swine production and processing chain

Methicillin-resistant Staphylococcus aureus (MRSA) has been a major public health concern. In this study, a total of 1485 samples from three swine farms, one slaughterhouse and one indoor market in Xiamen, China were collected in 2015, and the prevalence and profiles of MRSA were assessed. All the MRSA isolates were characterized by molecular typing, antibiotic susceptibility, coagulation activity, as well as PCR screening for 38 antibiotic resistance genes, two mobile genetic elements (lsa(E)-containing multiresistance gene cluster and Tn558), and 36 virulence genes. During the study, 54 of 1485 (3.6%) samples from the swine production, processing and retail chain were found positive for MRSA. A relatively rare SCCmecXII genotype was prevalent in swine farm (84.6%, 11/13) and slaughterhouse isolates (80.6%, 25/31), but absent in the market isolates (0%, 0/10). Notably, all staphylococcal cassette chromosome mec (SCCmec) type XII MRSA isolates were resistant to at least 6 classes of antibiotics, carried two mobile genetic elements (lsa(E)-containing multiresistance gene cluster and Tn558) and harbored multiple virulence genes. These multidrug resistant MRSA isolates could also coagulate both bovine and caprine plasma. Our results on the SCCmecXII MRSA isolates, particularly their profiles of related genotypes, antibiotic resistance and virulence determinants, illustrated the evolvement of livestock-associated (LA)-MRSA in the swine production environment and spread along the processing chain. The dominance of the SCCmecXII in MRSA isolates found in this study, differed from previous reports from China, indicated potential contribution associated with the production process.

In vitro activity of ceftaroline: A novel antibiotic against methicillin-resistant Staphylococcus aureus.

Staphylococcus is one of the most common causes of nosocomial infection, especially pneumonia, surgical site infections, blood stream infections, and continues to be a major cause of community-acquired infections. The emergence of penicillin resistance followed by the development and spread of strains resistant to the semisynthetic penicillins such as methicillin, oxacillin and nafcillin, macrolides, tetracycline, and aminoglycosides has made the treatment of staphylococcal infection a global challenge. To treat this multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA), the only option available is glycopeptides such as vancomycin. However, recently, vancomycin-intermediate S. aureus and vancomycin-resistant S. aureus strains have emerged with different resistance mechanism. There are newer drugs in the pipeline against MRSA such as ceftaroline, dalbavancin, oritavancin, and tedizolid; however, very little data are available for their use. Recently, ceftaroline has been approved by the US Food and Drug Administration for the treatment of acute bacterial skin and soft tissue infections and community-acquired bacterial pneumonia due to MRSA. Hence, we tried to evaluate in vitro activity of ceftaroline against MRSA. The aim of this study was to detect in vitro activity of new cephalosporin, ceftaroline, against MRSA. Thirty nonduplicate MRSA strains were collected from various clinical samples, and minimum inhibitory concentration (MIC) was detected using ceftaroline E-test strips. Twenty-eight MRSA isolates (93.33%) were found to be susceptible to ceftaroline. Ceftaroline demonstrated promising potency and coverage against MRSA isolates and can be considered an effective alternative treatment keeping vancomycin and linezolid as a reserved option.

Comparison of methicillin-resistant Staphylococcus aureus strains isolated in 2003 and 2008 with an emergence of multidrug resistant ST22: SCCmec IV clone in a tertiary hospital, Malaysia

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) continue to be a problem for clinicians worldwide. The objective of this study was to determine the changes in antibiograms of MRSA and their genotypic characteristics. The antibiograms of 162 MRSA isolates (52 from 2003 and 110 from 2008) from a tertiary hospital were analyzed by antimicrobial susceptibility tests, the Panton-Valentine leukocidin (PVL) and staphylococcal cassette chromosome mec (SCCmec) types were determined by polymerase chain reaction, and genetic relatedness by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). All the isolates were sensitive to vancomycin. Resistance to ciprofloxacin, clindamycin, erythromycin, and gentamicin remained high throughout the study period, although a small decrease was observed in 2008 for ciprofloxacin (96% to 90%) and gentamicin (90% to 83%). Similarly, a slight decrease in resistance toward fusidic acid (10% to 9%), linezolid (2% to 1%), rifampicin (8% to 4%), and teicoplanin (4% to 0%) was observed between 2003 and 2008. In contrast, there was a significant increase (p<0.05) in resistance rates toward trimethoprim-sulfamethoxazole, netilmicin, and tetracycline between 2003 and 2008. Ninety-six percent of the isolates from both 2003 and 2008 were multidrug resistant. Three SCCmec types (SCCmec type III, 90%; SCCmec type IV, 9%; SCCmec V, 1%) were observed. SCCmec type IV (n=15) and pvl gene (n=3) were detected in 2008 isolates but not in 2003 isolates. Most of the SCCmec type IV isolates (12 of 15) belonged to sequence type 22 (ST22) and were resistant to erythromycin and ciprofloxacin, with 11 being multidrug resistant. Most of the isolates were genetically related (F>0.8) as determined by PFGE. Some isolates from 6 years apart shared similar PFGE profiles, indicating the persistence of a particular genotype. Five STs (ST239, ST772, ST22, ST6, and ST1178) were identified among the 2008 isolates but only one ST (ST239) was observed in 2003 isolates. Vancomycin remains the most active agent invitro against S. aureus infection followed by linezolid and teicoplanin. The prevalence of resistance to fluoroquinolones, aminoglycosides (netilmicin), and tetracyclines had increased over the years. The Malaysian multidrug-resistant MRSA isolates were mostly SCCmec type III and ST239, although SCCmec type IV: ST22 is gaining importance. There was a correlation between resistotypes and PFGE profiles.

Household risk factors for colonization with multidrug-resistant Staphylococcus aureus isolates.

Antimicrobial resistance, particularly in pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), limits treatment options and increases healthcare costs. To understand patient risk factors, including household and animal contact, potentially associated with colonization with multidrug-resistant MRSA isolates, we performed a prospective study of case patients colonized with MRSA on admission to a rural tertiary care hospital. Patients were interviewed and antimicrobial resistance patterns were tested among isolates from admitted patients colonized with MRSA in 2009–10. Prevalence of resistance was compared by case-patient risk factors and length-of-stay outcome among 88 MRSA case patients. Results were compared to NHANES 2003–04. Overall prevalence of multidrug resistance (non-susceptibility to ≥four antimicrobial classes) in MRSA nasal isolates was high (73%) and was associated with a 1.5-day increase in subsequent length of stay (p = 0.008). History of hospitalization within the past six months, but not antimicrobial use in the same time period, was associated with resistance patterns. Within a subset of working-age case patients without recent history of hospitalization, animal contact was potentially associated with multidrug resistance. History of hospitalization, older age, and small household size were associated with multidrug resistance in NHANES data. In conclusion, recent hospitalization of case patients was predictive of antimicrobial resistance in MRSA isolates, but novel risk factors associated with the household may be emerging in CA-MRSA case patients. Understanding drivers of antimicrobial resistance in MRSA isolates is important to hospital infection control efforts, relevant to patient outcomes and to indicators of the economic burden of antimicrobial resistance.

Susceptibility Profile of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates to Antibiotics and Methanolic Extracts of Parkia biglobosa (Jacq) Benth

Aims: To study the susceptibility profile of methicillin-resistant Staphylococcus aureus (MRSA) isolates from orthopaedic patients to antibiotics and methanolic extracts of Parkia biglobosa. Background: Antimicrobial resistance in Staphylococcus aureus has attained alarming proportions worldwide; with methicillin resistant Staphylococcus aureus (MRSA) becoming a major pathogen of public health importance associated with community and hospital acquired infections. Wound infections in orthopaedic patients with multidrug resistant pathogens significantly delay or prevent the union of fractured bones. The increasing prevalence of multidrug resistance in Staphylococcus aureus isolates calls for the search for alternative anti-staphylococcal agents. Methodology: Suspected staphylococcal isolates from wound, skin and bed swab samples from orthopaedic patients in a tertiary hospital in Zaria, Nigeria were characterized by established microbiological procedures and their antibiotic susceptibility pattern determined by the Kirby-Bauer-CLSI modified disc agar diffusion (DAD) technique. The activity of crude methanolic extract of the root, stem bark and leaf of Parkia biglobosa on the isolates determined. Results: A total of 179 isolates were confirmed S. aureus: wounds (24.6%), skin (39.1%) and bed (36.3%). The isolation rates for MRSA from the various sites were: wound (75%), skin (51.4%) and bed (73.8%). Antibiotic susceptibility testing revealed that the isolates were generally resistant to ampicillin (100% for all sites); ceftriazone (wound 69.7%, skin 72.2%, bed 70.8%); gentamicin (wound 54.5%, skin 52.8%, bed 37.5%) and ciprofloxacin (wound 51.5%, skin 47.2%, bed 35.4%). The phytochemical screening of the methanolic extract of the leaf, root and stem bark of Parkia biglobosa showed the presence of saponin, tannin, flavonoids and cardiac glycosides. The stem bark of Parkia biglobosa showed the greatest activity against all the multidrug resistant MRSA isolates at the 10mg/ml-25mg/ml concentration range used. In the search for alternative antistaphylococcal agents from natural sources, Parkia biglobosa will be a possible candidate for further investigation. Conclusion: There was high prevalence of multidrug resistant Staphylococcus aureus isolates from the clinical and surveillance samples from the orthopaedic patients.

Susceptibility Profile of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates to Antibiotics and Methanolic Extracts of Parkia biglobosa (Jacq) Benth

Aims: To study the susceptibility profile of methicillin-resistant Staphylococcus aureus (MRSA) isolates from orthopaedic patients to antibiotics and methanolic extracts of Parkia biglobosa. Background: Antimicrobial resistance in Staphylococcus aureus has attained alarming proportions worldwide; with methicillin resistant Staphylococcus aureus (MRSA) becoming a major pathogen of public health importance associated with community and hospital acquired infections. Wound infections in orthopaedic patients with multidrug resistant pathogens significantly delay or prevent the union of fractured bones. The increasing prevalence of multidrug resistance in Staphylococcus aureus isolates calls for the search for alternative anti-staphylococcal agents. Methodology: Suspected staphylococcal isolates from wound, skin and bed swab samples from orthopaedic patients in a tertiary hospital in Zaria, Nigeria were characterized by established microbiological procedures and their antibiotic susceptibility pattern determined by the Kirby-Bauer-CLSI modified disc agar diffusion (DAD) technique. The activity of crude methanolic extract of the root, stem bark and leaf of Parkia biglobosa on the isolates determined. Results: A total of 179 isolates were confirmed S. aureus: wounds (24.6%), skin (39.1%) and bed (36.3%). The isolation rates for MRSA from the various sites were: wound (75%), skin (51.4%) and bed (73.8%). Antibiotic susceptibility testing revealed that the isolates were generally resistant to ampicillin (100% for all sites); ceftriazone (wound 69.7%, skin 72.2%, bed 70.8%); gentamicin (wound 54.5%, skin 52.8%, bed 37.5%) and ciprofloxacin (wound 51.5%, skin 47.2%, bed 35.4%). The phytochemical screening of the methanolic extract of the leaf, root and stem bark of Parkia biglobosa showed the presence of saponin, tannin, flavonoids and cardiac glycosides. The stem bark of Parkia biglobosa showed the greatest activity against all the multidrug resistant MRSA isolates at the 10mg/ml-25mg/ml concentration range used. In the search for alternative antistaphylococcal agents from natural sources, Parkia biglobosa will be a possible candidate for further investigation. Conclusion: There was high prevalence of multidrug resistant Staphylococcus aureus isolates from the clinical and surveillance samples from the orthopaedic patients.

Vancomycin resistance among methicillin resistant Staphylococcus aureus isolates from intensive care units of tertiary care hospitals in Hyderabad

Background & objectives:Multidrug resistant methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections and is on the rise. The glycopeptide vancomycin has been proposed as the drug of choice for treating such infections. The present study aimed at identifying the vancomycin resistance both phenotypically and genotypically among the MRSA isolates from two tertiary care hospitals in Hyderabad, south India.Methods:MRSA were isolated and identified from different clinical samples collected from ICUs of tertiary care hospitals in Hyderabad using conventional methods. Antibiogram of the isolates and vancomycin MIC were determined following CLSI guidelines. vanA was amplified by PCR using standard primers.Results:All vancomycin resistant S. aureus (VRSA) isolates were MRSA. The VRSA isolates were positive for vanA gene, except one which was negative. All VRSA had a vancomycin MIC in the range of 16-64 mg/l.Interpretation & conclusions:The increase in vancomycin resistance among MRSA and excessive use of antimicrobial agents have worsened the sensitivity. Larger studies need to be done in various geographical regions of the country to better define the epidemiology, mechanism of vancomycin resistance in S. aureus and its clinical implications.

KP009 Distribution of MRSA clonal groups at the Otto-von-Guericke University in Magdeburg from 2000 to 2003

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) continue to be a problem for clinicians worldwide. The objective of this study was to determine the changes in antibiograms of MRSA and their genotypic characteristics.The antibiograms of 162 MRSA isolates (52 from 2003 and 110 from 2008) from a tertiary hospital were analyzed by antimicrobial susceptibility tests, the Panton-Valentine leukocidin (PVL) and staphylococcal cassette chromosome mec (SCCmec) types were determined by polymerase chain reaction, and genetic relatedness by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST).All the isolates were sensitive to vancomycin. Resistance to ciprofloxacin, clindamycin, erythromycin, and gentamicin remained high throughout the study period, although a small decrease was observed in 2008 for ciprofloxacin (96% to 90%) and gentamicin (90% to 83%). Similarly, a slight decrease in resistance toward fusidic acid (10% to 9%), linezolid (2% to 1%), rifampicin (8% to 4%), and teicoplanin (4% to 0%) was observed between 2003 and 2008. In contrast, there was a significant increase (p < 0.05) in resistance rates toward trimethoprim-sulfamethoxazole, netilmicin, and tetracycline between 2003 and 2008. Ninety-six percent of the isolates from both 2003 and 2008 were multidrug resistant. Three SCCmec types (SCCmec type III, 90%; SCCmec type IV, 9%; SCCmec V, 1%) were observed. SCCmec type IV (n = 15) and pvl gene (n = 3) were detected in 2008 isolates but not in 2003 isolates. Most of the SCCmec type IV isolates (12 of 15) belonged to sequence type 22 (ST22) and were resistant to erythromycin and ciprofloxacin, with 11 being multidrug resistant. Most of the isolates were genetically related (F > 0.8) as determined by PFGE. Some isolates from 6 years apart shared similar PFGE profiles, indicating the persistence of a particular genotype. Five STs (ST239, ST772, ST22, ST6, and ST1178) were identified among the 2008 isolates but only one ST (ST239) was observed in 2003 isolates.Vancomycin remains the most active agent in vitro against S. aureus infection followed by linezolid and teicoplanin. The prevalence of resistance to fluoroquinolones, aminoglycosides (netilmicin), and tetracyclines had increased over the years. The Malaysian multidrug-resistant MRSA isolates were mostly SCCmec type III and ST239, although SCCmec type IV: ST22 is gaining importance. There was a correlation between resistotypes and PFGE profiles.

Two-year assessment of the pathogen frequency and antimicrobial resistance patterns among organisms isolated from skin and soft tissue infections in latin American hospitals: Results from the SENTRY antimicrobial surveillance program, 1997-98

Objectives: This study was conducted to evaluate the frequency of occurrence and antimicrobial susceptibility of bacterial isolates collected from patients with skin and soft tissue infections (SSTI) in Latin American hospitals, as part of the SENTRY Antimicrobial Surveillance Program. The dissemination of multidrug- resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) among the Latin American countries also was studied. Material and Methods: A total of 885 bacterial isolates were analyzed. At the monitoring laboratory, antimicrobial susceptibility testing tilizing the reference broth microdilution method and confirmation of species identification were performed. Enterobacteriaceae possibly producing extended-spectrum β-lactamases (ESBL) and MDR-MRSA isolates were genotyped by ribotyping using the RiboPrinter TM and by pulsed-field gel electrophoresis. Results: Staphylococcus aureus (31 %) was the most common etiologic agent causing SSTI, followed by Escherichia coli (13.4%) and Pseudomonas aeruginosa (11 %). Thirty-one percent of S. aureus isolates were resistant to oxacillin (methicillin). The presence of ESBL phenotypes was markedly higher among the Klebsiella pneumoniae (35.5%) than E. coli isolates (10.2%). Meropenem was the compound with the highest susceptibility rate among the Enterobacteriaceae (100%) and P. aeruginosa (95%) isolates. A great genetic similarity was observed among the MDR-MRSA in Latin America. Conclusion: High resistance rates to antimicrobial drugs among the most frequent bacterial pathogens were observed in 10 medical centers in Latin America. This study also demonstrated a clonal dissemination of a MDR-MRSA strain in several nations.