Methicillin Resistance S. Aureus Research Articles

Nasal Carriage Rate of Staphylococcus aureus, Its Associated Factors, and Antimicrobial Susceptibility Pattern Among Health Care Workers in Public Hospitals, Harar, Eastern Ethiopia.

Staphylococcus aureus is the bacteria that colonizes the nasal nares of health-care workers and serves as a reservoir for the spread of pathogen for subsequent infections, mainly Methicillin-resistant Staphylococcus aureus. However, there is a limited study conducted regarding this topic in Harar, Eastern Ethiopia. The main objective of this study was to determine the prevalence of nasal carriage of Staphylococcus aureus, associated factors and antimicrobial susceptibility patterns among health-care workers of public hospitals in Harar, Eastern Ethiopia from May 15 to July 30, 2021. A hospital-based cross-sectional study was conducted on 295 health-care workers. A simple random sampling technique was used to select the participant. Nasal swabs were collected and cultured at 35°C for 24hrs. S. aureus was identified using the coagulase test and catalase test. Methicillin resistance S. aureus (MRSA) was screened using a cefoxitin disc on Muller Hinton agar using the Kirby-Bauer disc diffusion method. Data were entered into EPI-Info version-7 and transferred to SPSS-20 for analysis. Factors associated with nasal carriage of Staphylococcus aureus were determined by using chi-square analysis. A p-value of less than 0.05 was considered statistically significant. The prevalence of Staphylococcus aureus in this study was 15.6% (95% CI: 11.7%, 20.3%) and methicillin-resistant Staphylococcus aureus was 11.2% (95% CI: 7.8%, 15.4%), respectively. Age (P < 0.001), work experience (p < 0.001), working unit (p < 0.02), antibiotic use within 3 months (p < 0.001), hand washing habit (p < 0.01), hand rub use (p < 0.001), living with smokers (p < 0.001), living with pets (p < 0.001) and having chronic diseases (p < 0.001) were found significantly associated with Staphylococcus aureus nasal carriage. The prevalence of Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus are high in our study. The study emphasizes the need for regular surveillance among hospital staff and the environment to prevent MRSA transmission among health-care personnel.

Isolation and characterization of a broad-spectrum phage SapYZU11 and its potential application for biological control of Staphylococcus aureus

Staphylococcus aureus, a prominent pathogen, is frequently encountered in clinical and food-processing settings. Given its ability to develop antimicrobial resistance, effective control strategies are required to ensure microbial safety. In this study, four lytic S. aureus phages (SapYZU10, SapYZU11, SapYZU12, and SapYZU13) were isolated from sewage samples in Yangzhou, China. Their biological characteristics and bactericidal effect against S. aureus isolates in vitro and in milk and fresh pork were evaluated. Their activities remained relatively stable under stressful conditions (-80–70°C, pH 3.0–12.0). Notably, SapYZU11 (100%, 53/53) effectively lysed all 53 S. aureus strains, followed by SapYZU12 (90.57%, 48/53), SapYZU13 (79.25%, 42/53), and SapYZU10 (71.70%, 38/53). Among the phages with short latent periods (10–20 min), SapYZU11 had a larger burst size (152.00 plaque forming units [PFU]/mL) and no genes related to antibiotic resistance and virulence. Furthermore, SapYZU11 effectively eradicated S. aureus and its cocktail (YZUsa1, YZUsa4, YZUsa12, YZUsa14, and methicillin-resistance S. aureus (MRSA) JCSC 4744) in Luria–Bertani broth and both food items. Particularly in milk, SapYZU11 with a multiplicity of infection (MOI) of 100 inhibited MRSA JCSC 4744 strain and S. aureus cocktail with maximum reduction levels of 5.03 log (Lg) colony-forming unit (CFU)/mL and 2.80 Lg CFU/mL, respectively. Conversely, contaminated pork treated with three MOIs of SapYZU11 at 25°C and 4°C resulted in reductions of 0.29–1.29 Lg CFU/mL and 0.11–0.32 Lg CFU/mL, respectively. Therefore, SapYZU11 proved as a promising biocontrol agent against S. aureus in different food production settings.

Aetiology of ear infection and antimicrobial susceptibility pattern among patients attending otorhinolaryngology clinic at a tertiary hospital in Dar es Salaam, Tanzania: a hospital-based cross-sectional study

ObjectivesTo determine the aetiological pathogens causing ear infections and their antimicrobial susceptibility patterns among patients with ear complaints at a tertiary hospital in Dar es Salaam.DesignHospital-based cross-sectional study.SettingsOtorhinolaryngology clinic at...

Prevalence and Susceptibility of Staphylococcus aureus Nasal Carriage Strains Isolated from Haemodialysis Patients

Introduction: Staphylococcus aureus is part of the normal human flora that can commonly be found on the skin and mucous membranes of the nasal area. However, in immunosuppressed patients such as those with kidney failures, colonization can potentially lead to infection. There is a concern of increasing antibiotic resistance in S. aureus. This study aimed to determine the prevalence of S. aureus nasal colonization and its antimicrobial susceptibility among haemodialysis-dependent populations. Methods: A cross-sectional study at the Nephrology Unit, Hospital Canselori Tuanku Mukhriz (HCTM) was conducted among haemodialysis-dependent patients between February 2017 to February 2018. Nasal swabs were obtained and cultured on mannitol salt agar. S. aureus isolates were identified by gram staining, tube coagulase and Deoxyribonuclease (DNase). Cefoxitin disc (30 µg) were used to identified the presence of MRSA (methicillin-resistance S. aureus). The S. aureus colonies were further tested against six antibiotics using Kirby Bauer disc diffusion. Result: A total of 134 patients were recruited. S. aureus isolates were detected from 27 patients (20.1%). All S. aureus were phenotypically identified as methicillin-sensitive S. aureus (MSSA) based on the cefoxitin disc. Teicoplanin and linezolid were the most effective with 100% susceptibility. S. aureus exhibited a high resistance rate towards erythromycin (29.6%). No MRSA was isolated in this study. Conclusion: This study highlighted the high prevalence of S. aureus nasal colonization in haemodialysis patients. Teicoplanin and linezolid were found to be the most effective antibiotics against isolated S. aureus.

1319. Evolution of Invasive and Colonizing Pediatric Staphylococcus aureus Isolates

Abstract Background Staphylococcus aureus is the most common invasive bacterial pathogen in children. The constant evolution of S. aureus is a barrier to the development of successful interventions. A detailed understanding of the current molecular epidemiology of actively circulating, invasive S. aureus strains and a comparison to both colonization strains and historical invasive strains to determine which virulence factors and genetic lineages are preserved over time are important unmet needs in this field. Methods We compared four groups of S. aureus isolates: 45 invasive strains obtained during the epidemic methicillin-resistance S. aureus (MRSA) peak (2010-2012); 74 invasive contemporary strains (2015-2021); 61 colonizing strains from 2004; and 30 colonizing strains from 2021. Genetic relatedness (via clonal complex typing) and virulence factor presence were determined via whole genome sequencing. Results Among invasive isolates, the prevalence of clonal complex 8 (CC8) decreased significantly over time from 87% to 46% among typeable strains (p&amp;lt; 0.05, Fig.1). Similarly, the presence of Panton-Valentine leucocidin (PVL) decreased from 71% to 40% (p&amp;lt; 0.01). 56% of invasive isolates from 2010-2012 were MRSA, vs 37% from 2015-2021 (p= 0.05, Fig. 2). In contrast to PVL, the presence of leukocidins LukED and LukAB remained stably prevalent over time at 84% and 100% (Fig. 3). Colonization isolates overall remained diverse, with no dominant clonal complex (Fig. 1). Figure 1Figure 2Figure 3 Conclusion Invasive S. aureus molecular epidemiology has changed significantly over the past decade. The former dominance of CC8 and PVL-positive MRSA strains has shifted to a more diverse, predominantly MSSA group of contemporary strains. Other virulence factors (LukED, LukAB) have remained prevalent among invasive strains regardless of genetic lineage. Targets of intervention should be those that are preserved throughout the evolution of this major human pathogen. Disclosures All Authors: No reported disclosures.

Survey on Methicillin Resistance and Panton Valentine Toxin of Staphylococcus aureus Strains Isolated from Raw Milk and Ice Cream: Molecular Study by Multiplex PCR

Staphylococcus aureus is a very important pathogenic bacterium that causes nosocomial and community-acquired infections in humans, and is also one of the leading pathogens that causes food-borne poisoning. The presence of S. aureus in raw milk and dairy products, and especially the presence of MRSA (Methicillin Resistance S. aureus) strains, poses a potential risk to public health. The aim of this study was to investigate the presence of methicillin resistance and Panton-Valentine Leucocidin (PVL) toxin in Staphylococcus aureus isolated and identified from raw milk and ice cream in Konya (Turkey) by multiplex PCR method. A total of 55 S. aureus were isolated 49 (18%) from 260 raw milk samples collected from various farms and 6 (4%) from 150 ice cream samples sold in patisseries. The obtained isolates were identified as S. aureus with conventional and genotypic methods. Multiplex PCR was performed to detect the 16S rRNA, mecA, femA and lukS genes. While no mecA gene was detected in any of the 49 S. aureus isolates obtained from raw milk samples, the presence of mecA gene was observed in one of the 6 S. aureus isolates isolated from ice cream samples. The PVL gene was not detected in any of the S. aureus isolates studied. S. aureus contamination is common in raw milk samples and ice cream samples. In order to avoid this, it is necessary to comply with the hygiene conditions and increase the precautions even more.

Cytotoxic activity of Staphylococcus aureus isolates from a cohort of Mexican children with cystic fibrosis.

Cystic fibrosis (CF) is a genetic disease in which thick, sticky mucus is produced in the lungs (and other organs) that impairs ciliary clearance, leading to respiratory problems, increased chronic bacterial infections, and decreased lung function. Staphylococcus aureus is one of the primary bacterial pathogens colonizing the lungs of CF patients. This study aimed to characterize the genetic relatedness of S. aureus, its presence in children with CF, and its cytotoxic activity in THP1 cell-derived macrophages (THP1m). Genetic relatedness of S. aureus isolates from a cohort of 50 children with CF was determined by pulsed-field gel electrophoresis (PFGE). The VITEK 2 automated system was used to determine antimicrobial susceptibility, and methicillin-resistance S. aureus (MRSA) was determined by diffusion testing using cefoxitin disk. The presence of mecA and lukPV genes was determined by the polymerase chain reaction and cytotoxic activity of S.aureus on THP1m by CytoTox 96® assay. From 51 S. aureus isolates from 50 children with CF, we identified 34pulsotypes by PFGE. Of the 50 children, 12 (24%) were colonized by more than one pulsotype, and 5/34 identified pulsotypes(14.7%) were shared between unrelated children. In addition, 3/34 pulsotypes (8.8%) were multidrug-resistant (MDR), and2/34 (5.9%) were MRSA. Notably, 30/34 pulsotypes (88.2%) exhibited cytotoxicity on THP1m cells and 14/34 (41.2%) alteredTHP1m monolayers. No isolate carried the lukPV gene. Although a low frequency of MRSA and MDR wasfound among clinical isolates, most of the S. aureus pulsotypes identified were cytotoxic on THP1m.

Antibiotic Susceptibility Pattern of Staphylococcus aureus Isolated from Pus/Wound Swab from Children Attending International Friendship Children's Hospital

A wound gets infected when the organism gets invaded through the breached skin, proliferated and production of various enzymes, toxins, etc. In order to treat the wound infection, antibiotic susceptibility pattern of organism should be determined before the prescription of the medicine. The present study was conducted from September 2017 to March 2018 with an aim to determine antibiotic susceptibility pattern of Staphylococcus aureus identified from the pus/wound swab among the patients visiting the International Friendship Children's Hospital, Kathmandu, Nepal. Total 270 sample were processed, isolated and identified using standard microbiological procedure and biochemical test. Antibiotic susceptibility test was carried out by using Modified Kirby Bauer's Disc Diffusion Method. Out of total sample, 51.48% (139) showed growth. The growth distribution was found to be high in out-patient department 84.9% (118) than in-patient department 15.1% (21). Among 139 positive growth, 83.5% were gram positive and 16.5% were gram negative. All together 12 different organisms were identified, among which S. aureus was found to be predominant organism 105 (75.5%). S. aureus was found to be sensitive towards Linezolid followed by Doxycycline whereas it was found resistant towards Ciprofloxacin. Among S. aureus identified, 50% were Multidrug resistant (MDR) S. aureus and 55% were Methicillin resistance S. aureus (MRSA). MRSA was found to be sensitive towards Linezolid followed by Doxycycline and resistant towards Ciprofloxacin. The association between MDR and MRSA was found positively significant (i.e. p-value = 0.000). All strains of S. aureus were found to be sensitive towards Vancomycin. 22.86% were double disk diffusion test (D-test) positive. The prevalence of D-test was found to be high in MRSA (75%). The relationship between D-test and MRSA was found to be significantly correlated with each other (r = 0.39). Linezolid, Chloramphenicol, Vancomycin and Doxycycline is a drug of a choice for both S. aureus and MRSA infection.

Molecular detection and antibiogram of Staphylococcus aureus in rabbits, rabbit handlers, and rabbitry in Terengganu, Malaysia.

Objectives:This study aims to investigate the prevalence and antibiogram of Staphylococcus aureus and methicillin-resistance S. aureus (MRSA) in rabbits, rabbit handlers, and rabbitry environments in Terengganu. Materials and Methods:Swab samples from 183 rabbits (183 oral and 183 ear swabs), 45 rabbit handlers (45 oral and 45 nasal), and environmental (n = 180) samples from rabbitries were collected from 10 rabbit farms in Terengganu. The associated S. aureus isolates from the swabs were isolated using phenotypic microbiology tests. The bacteria were confirmed by polymerase chain reaction targeting nuc (S. aureus) and mecA (MRSA) genes. The antibiogram of all S. aureus isolates was determined using the Kirby–Bauer test. Results:Staphylococcus aureus was detected in 19% of rabbits, 26.7% of rabbit handlers, and 8.8% of swabs from the rabbitry environment. However, MRSA (0%) could not be detected. Antibiotic susceptibility test revealed that S. aureus from rabbits showed low resistance (<20%) against 15 different antibiotics while fully susceptible to 4 antibiotics. Meanwhile, S. aureus from rabbit handlers showed high resistance against penicillin (86%), oxacillin (64%), and amoxicillin (50%). Conclusions:This study suggests the emergence of antibiotic-resistant S. aureus in rabbit farms settings. Therefore, careful selection of antimicrobial agents will be essential to preserve the effectiveness of treatments toward S. aureus infections.

The Characterization of mecA Gene and SCCmec Typing in Clinical Samples of MRSA

MRSA is a major pathogen worldwide and its infections are associated with increased morbidity and mortality, in comparison with other S. aureus infections. The study was designed to characterize the mecA gene and staphylococcal cassette chromosome (SCCmec) in methicillin resistance S. aureus (MRSA). A total of 20 presumptive S. aureus strains were collected from one of the teaching hospitals in Selangor. Using standard biochemical tests, all the isolates were verified as S. aureus. When tested against cefoxitin, 80% of the isolates were confirmed as MRSA. All the MRSA isolates were further subjected to polymerase chain reaction (PCR) to detect the presence of mecA gene. Nine out of the 16 MRSA isolates (56%) were mecA positive, whereas the remaining four were mecA negative. The 16 MRSA with positive mecA gene were further subjected to SCCmec typing of type I, II, III, IV and V. The most frequent SCCmec types were type III (56%) followed by type II (33%), and type IV (11%). None of the isolates were of SCCmec type I or V. Our study indicates that SCCmec type III is predominant among the isolates which is in agreement with other studies conducted on clinical strains of MRSA.&#x0D;

Staphylococcal Cassette Chromosome &amp;lt;i&amp;gt;mec&amp;lt;/i&amp;gt; (SCC&amp;lt;i&amp;gt;mec&amp;lt;/i&amp;gt;) Gene Typing in Detection of Methicillin-Resistant &amp;lt;i&amp;gt;Staphylococcus aureus&amp;lt;/i&amp;gt;: Toward Precise Detection in Health Care Facility

Background: Blood stream infections (BSI) are considered key issues in critical care units. Methicillin resistant Staphylococcus aureus, MRSA-related infections, are considered a major health problem. This is attributed to the emerging new society dangerous strains with continuous antibiotics pressure and fluctuations in resistance patterns. Aim: We aimed to study epidemiology of methicillin resistance S. aureus (MRSA) infections by using conventional phenotypic methods [cefoxitin disk diffusion (CDD) and oxacillin screening agar] and molecular typing of the mec-gene (SCCmec) using multiplex PCR in Suez Canal University Hospital. Methods: 100 non-repetitive staphylococcus aureus were collected and identified morphologically and biochemically by standard laboratory procedures. The strains were considered MRSA if the MIC of oxacillin ≥ 4 μg/ml, and the inhibition zone of cefoxitin was ≤21 mm (CDD). Characterization of SCCmec elements in isolated MRSA strains was done via multiplex-PCR. Results: From total of 100 isolates, eighty were detected as MRSA by using CDD (sensitivity and specificity were 83.6% and 24.4% respectively) and only 65 by using oxacillin screening agar (sensitivity and specificity were 85.5% and 60% respectively). MecA gene was identified in 55 samples; the majority of isolates were SCCmec type IVa (63.7%). Both type I and III of SCCmec couldn’t be detected. Antimicrobial sensitivity rates among SCCmec-V isolates were expectedly higher than those among Type-II isolates. SCCmec type II was characterized by 100% resistant to ciprofloxacin, erythromycin, oxacillin and cefepime as well as greater resistance to clindamycin (70%) with the same pattern between all typing strains (7 strains). Conclusion: SCCmec types IVa and V are generally dominant in our community with no detection of SCCmec types I or III. PCR is the optimum method for MRSA detection.

Staphylococcus aureus Isolated From Retail Meat and Meat Products in China: Incidence, Antibiotic Resistance and Genetic Diversity.

This study was to estimate the prevalence and characteristics of Staphylococcus aureus from 1,850 retail meat and meat products in China during July 2011 to June 2016. The samples were collected covering most provincial capitals in China, including 604 raw meat, 601 quick-frozen meat, and 645 ready-to-eat meat. Using the qualitative and quantitative methods, all 39 cities had S. aureus-positive samples, and S. aureus was detected in 35.0% (647/1,850) of the samples. The levels of S. aureus in retail meat showed that the MPN value of the majority of the positive samples ranged from 0.3 to 100 MPN/g. Twenty-four antibiotics were used to test all 868 S. aureus isolates for antibiotic susceptibility. Only 11 isolates (1.26%) were susceptible to all antibiotics, whereas most isolates (821/868, 94.6%) showed resistance or intermediary resistance to more than three or more antibiotics. Of these strains, 104 (12.0%) were resistant to more than 10 antibiotics. However, the most frequent resistance was observed to ampicillin (85.4%), followed by penicillin (84.6%), erythromycin (52.7%), tetracycline (49.3%), kanamycin (45.3%), telithromycin (30.1%), clindamycin (29.6%), streptomycin (21.1%), norfloxacin (20.4%), gentamicin (19.4%), fusidic acid (18.4%), ciprofloxacin (16.9%), chloramphenicol (13.1%), amoxycillin/clavulanic acid (11.0%), and others (<10%). 7.4% of isolates (62/868) were confirmed as methicillin-resistance S. aureus (MRSA). By molecular typing analysis, there were 164 spa types and 111 STs were identified, including 15 novel spa types and 65 newly STs by multilocus sequence typing (MLST) and spa typing. Despite the wide genetic diversity observed among the 868 isolates, a great proportion of the population belonged to finite number of major clones: ST1-t127 (93/868, 10.7%) and ST7-t091 (92/868, 10.6%), ST5-t002 (42/868, 4.8%), ST398-t034 (40/868, 4.6%), ST188-t034 (38/868, 4.4%), ST59-t437 (30/868, 3.5%), ST6-t701 (29/868, 3.3%), and ST9-t899 (27/868, 3.1%) in China. This study reflects S. aureus was readily detected in Chinese retail meat and meat products but the level were not very excessive. In this study, the high antibiotic resistance is alarming and raising public health concern. In additions, most of molecular types of isolates have been linked to human infections around the world, indicating that these types of S. aureus in China have a theoretical pathogenic potential.

Investigation of the presence of pantone-valentine leukocidin in Staphylococcus aureus strains isolated from orthopedic surgical site infections

Staphylococcus aureus is one of the most clinically important bacteria causing infection in humans. It is an important pathogen in surgical site infections (SSIs), especially after orthopedic surgery. Pantone-valentine leukocidin (PVL) has a great importance in the virulence of S.aureus because it can destroy polymorphonuclear cells by necrosis or apoptosis. The spread of PVL positive S.aureus is a great concern, since it may become an important factor for increased morbidity and mortality in SSIs, especially after surgery. In this study, we aimed to investigate the presence of PVL in S.aureus strains isolated from patients who had surgical site infections after orthopedic surgery, and also the clinical status of these patients. Between 2013 and 2017, 101 patients who had SSIs due to S.aureus after orthopedic surgery were included in the study. Identification of the strains was determined by conventional methods and "Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry" (MALDI-TOF MS). Methicillin resistance was determined by Kirby-Bauer disc diffusion method and automated system (Vitek 2, bioMérieux, France). The PVL gene region was investigated by polymerase chain reaction (PCR) method by using the primers Luk-PV-1 and Luk-PV-2. The duration of the patients' hospitalization, C-reactive protein (CRP) and sedimentation levels and clinical status were obtained from the hospital information system, retrospectively. Fifteen (14.9%) of the isolates were methicillin resistance S.aureus (MRSA) and 86 (85.1%) were methicillin susceptibility S.aureus (MSSA). PVL positivity was detected in 14 (13.9%) isolates (3 MRSA, 11 MSSA). The mean hospital stays in PVL-negative patients were 17 (5-73) days and 46 (21-103) days in PVL-positive patients. It was observed that the serologic markers CRP and sedimentation were between 5-7 and 40-60 in PVL negative patients, and between 11-20 and 90-110 in PVL positive patients, respectively. In PVL-negative patients, serologic markers improved in 7-10 days, while in PVL-positive patients they were improved in 17-32 days. Osteomyelitis occurred in six patients (2 PVL positive MRSA, 1 PVL positive MSSA and 3 PVL negative MRSA). In two of the patients who have developed osteomyelitis with PVL-positive MRSA, PVL gene positive S.aureus isolates were observed in their orthopedic SSIs. We also determined that these isolates increased the hospitalization days, improvement time of serological markers and mortality. It is worrisome to isolate PVL-positive S.aureus strains in SSIs. Therefore, we believe that it would be useful to take infection control measures to prevent the spread of these strains in the hospital setting.

Comparación de las características y curso clínico de la endocarditis infecciosa por Staphylococcus aureus meticilino sensible versus meticilino resistente

IntroductionStaphylococcus aureus is one of the most common sources of infectious endocarditis. There are few studies in Latin America that report on the differences between the methicillin resistance profiles. ObjectiveTo describe the characteristics and clinical course of patients with methicillin-sensitive S. aureus (MSSA) compared to methicillin-resistance S. aureus (MRSA) MethodsAn observational, retrospective study was conducted on a historical cohort of adult patients with a confirmed diagnosis of endocarditis between the years 2011 and 2015. Patients positive for S. aureus were selected and the characteristics and clinical course and the cases of MSSA were compared with those of MRSA. ResultsA total of 86 patients with endocarditis were included, of whom 28 (33%) had an infection due to S. aureus, and 21 (75%) had endocarditis due to methicillin-sensitive S. aureus, and 7 (25%) due to MRSA. In the MSSA group, 11 (52.3%) were infections associated with health care. The majority (85.7%) of cases of MRSA were community acquired. The endocarditis mortality due to MSSA was higher than that caused by MRSA (33.3% vs. 14%). ConclusionsS. aureus continues to be the most common agent in endocarditis, with MSSA being more common. The embolic events and the severity were greater in MSSA. The majority of endocarditis due to MRSA is acquired in the community, and for this reason it is suggested starting empirical cover against MRSA in all cases of community acquired endocarditis.

Molecular analysis of immune evasion cluster (IEC) genes and intercellular adhesion gene cluster (ICA) among methicillin-resistant and methicillin-sensitive isolates of Staphylococcus aureus.

SummaryIntroductionResistance to antibiotics and presence of virulence factors play an important role in increased mortality associated with infection due to Staphylococcus aureus. In this study, we determine antibiotic resistance pattern, presence of the icaADBC locus as well as biofilm formation and distribution and diversity the immune evasion cluster (IEC) genes in clinical isolate of S. aureus from Kerman, Iran.Materials and methodsDuring 15 months, 100 clinical isolates S. aureus recovered from different patients were admitted to Kerman University affiliated hospitals. Resistance to different antibiotic agents was determined by disk diffusion method. Phenotypic method was used to the determination of biofilm formation ability and methicillin-resistance S. aureus (MRSA). Polymerase chain reaction technique (PCR) was used to the detection of nuc, mecA, icaA, icaD, icaB, icaC, scn, sea, sak, sep and chp genes.ResultsForty-four isolates were considered as MRSA and all of isolates were sensitive to vancomycin and linezolid. Our results showed, 77.2% (34/44) of MRSA and 8.9 % (5/56) of MSSA isolates were multidrug resistant. The predominant IEC variant was type B and our results displayed that 77.7% of the MRSA isolates harbor loci icaD and mecA. There was no significant difference in production biofilm between MSSA and MRSA isolates (P ≥ 0.05). There was significant difference in presence IEC types between MSSA and MRSA isolates (P = 0.000).ConclusionsThe presence of icaADBC locus may not be a determining factor for biofilm formation in Staphtlocooci and other mechanisms might be involved in this process.The high prevalence IEC types in MSSA isolates can indicate that the presence of these genes can be an advantage for pathogenesis of these isolates in different infections.

The Frequency of Staphylococcus aureus Isolated from Endocervix of Infertile Women in Northwest Iran.

Infertility is one of the major social issues. Due to the asymptomatic cervical infection associated with Staphylococcus aureus (S. aureus), the majority of patients remain undiagnosed. The present study intended to assess the frequency of S. aureus isolated from infertile women's endocervix in northwest Iran. In a descriptive cross sectional study, specimens were randomly collected during vagina examination using a sterile speculum and swabbing. After performance of antibiotic susceptibility testing, polymerase chain reaction (PCR) was used to identify methicillin-resistance S. aureus (MRSA) and toxic shock syndrome toxin-1 (TSST-1). About 26 (26%) and 9 (9%) women's urogenital tracts were colonized by S. aureus and Candida spp., respectively, of which three (11.5%) patients were infected with fungi and S. aureus, simultaneously. Antibiotic susceptibility results showed high activity of vancomycin and co-trimoxazole on isolates. Regarding PCR results, mecA sequences were detected in 7 (26.9%) strains, whilst the tst gene encoding TSST-1 was not detected in any of clinical strains. The prevalence of S. aureus was very high in infertile women. Therefore, it demands all patients undergoing infertility treatment to be investigated thoroughly for this type of infection.

Prevalence and phenotypic detection of methicillin resistance Staphylococcus aureus between ruminants butchered for humanoid intake and animal handlers in Maiduguri, Nigeria

Objective: The objectives of this study was to investigate phenotypically the prevalence of Staphylococcus aureus and Methicillin Resistance S. aureus (MRSA) in ruminants and animal handlers in Maiduguri, Nigeria. Materials and methods: A total of 937 samples (900 nasal and skin swabs of cattle and 37 humans samples) were collected in Maiduguri metropolis. The samples were inoculated onto mannitol salt agar (MSA) and blood agar, and the cultrue plates were incubated at 37 o C for 24 h. The S. aureus colonies showing golden yellow color on MSA were primarily identified as S. aureus , which were then subjected for catalase and coagulase tests. All S. aureus were finally screened for the presence of MRSA on oxalate resistant screening agar (ORSAB) medium. Antimicrobial susceptibility of the MRSA were measured by disc diffusion method. Results: The overall prevalence of S. aureus was 44.3% (n=414/937). The MRSA could be detected in 12.1% (n=113/937) samples. Considerign different species, S. aureus could be isolated from 137 (45.6%), 148 (49.3%) and 119 (39.7%), 11 (29.7%) cattle, sheep, goat and humans, respectively. In ruminants, 27.7% (n-83/300) bulls were positive for S. aureus . Similarly, 10.7% (n=32/300) and 22.3% (n=67/300) were positive for S. aureus in rams and bucks, respectively. On the other hand, 18% (n=54/300), 38.7% (n=116/300) and 17.3% (n=52/300) samples from cows, ewes and does were positive for S. aureus . The highest MRSA could be isolated from ewes (9.3%; n=28/300) follwed by bulls (7%; n=21/300) and bucks (6.7%; n=20/300). In humans, 13.5% (n=5/37) samples were positive for MRSA. Conclusion: S. aureus and MRSA infections in ruminants and animal handlers are documented in this study. The MRSA may exert public health threat to humans. http://doi.org/10.5455/javar.2016.c145

Anti-biofilm efficacy of silver nanoparticles against MRSA and MRSE isolated from wounds in a tertiary care hospital.

Different approaches have been used for preventing biofilm-related infections in health care settings. Many of these methods have their own de-merits, which include chemical-based complications; emergent antibiotic resistant strains, etc. The formation of biofilm is the hallmark characteristic of Staphylococcus aureus and S. epidermidis infection, which consists of multiple layers of bacteria encased within an exopolysachharide glycocalyx. Nanotechnology may provide the answer to penetrate such biofilms and reduce biofilm formation. Therefore, the aim of present study was to demonstrate the biofilm formation by methicillin resistance S. aureus (MRSA) and methicillin resistance S. epidermidis (MRSE) isolated from wounds by direct visualisation applying tissue culture plate, tube and Congo Red Agar methods. The anti-biofilm activity of AgNPs was investigated by Congo Red, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) techniques. The minimum inhibitory concentration (MIC) was found to be in the range of 11.25-45 μg/ml. The AgNPs coated surfaces effectively restricted biofilm formation of the tested bacteria. Double fluorescent staining (propidium iodide staining to detect bacterial cells and fluorescein isothiocyanate concanavalin A (Con A-FITC) staining to detect the exopolysachharides matrix) technique using CLSM provides the visual evidence that AgNPs arrested the bacterial growth and prevent the glycocalyx formation. In our study, we could demonstrate the complete anti-biofilm activity AgNPs at a concentration as low as 50 μg/ml. Our findings suggested that AgNPs can be exploited towards the development of potential anti-bacterial coatings for various biomedical and environmental applications. In the near future, the AgNPs may play major role in the coating of medical devices and treatment of infections caused due to highly antibiotic resistant biofilm.

Complestatin exerts antibacterial activity by the inhibition of fatty acid synthesis.

Bacterial enoyl-acyl carrier protein (ACP) reductase has been confirmed as a novel target for antibacterial drug development. In the screening of inhibitors of Staphylococcus aureus enoyl-ACP reductase (FabI), complestatin was isolated as a potent inhibitor of S. aureus FabI together with neuroprotectin A and chloropeptin I from Streptomyces chartreusis AN1542. Complestatin and related compounds inhibited S. aureus FabI with IC₅₀ of 0.3-0.6 µM. They also prevented the growth of S. aureus as well as methicillin-resistance S. aureus (MRSA) and quinolone-resistant S. aureus (QRSA), with minimum inhibitory concentrations (MICs) of 2-4 µg/mL. Consistent with its FabI-inhibition, complestatin selectively inhibited the intracellular fatty acid synthesis in S. aureus, whereas it did not affect the macromolecular biosynthesis of other cellular components, such as DNA, RNA, proteins, and the cell wall. Additionally, supplementation with exogenous fatty acids reversed the antibacterial effect of complestatin, demonstrating that it targets fatty acid synthesis. In this study, we reported that complestatin and related compounds showed potent antibacterial activity via inhibiting fatty acid synthesis.

Prevalence of mecA, PVL and ica genes in Staphylococcus aureus strains isolated from urinary tract infections patients

The prevalence of Staphylococcus aureus among urinary tract infections (UTIs) patients has been increasing worldwide. The aim of this study was to determine the occurrence of the mecA, PVL, ica genes in a collection of MRSA urinary isolates by PCR. Methicillin resistance S. aureus (MRSA) is considered to have emerged from S. aureus through the acquisition of staphylococcal cassette chromosome (SCCmec), which carries the mecA gene for methicillin resistance. Panton-Valentine leukocidin (PVL)-producing strains of MRSA appear to be associated with increased risk of transmission, complications and hospitalization. IcaA and icaD genes have been reported to play a significant role in biofilm formation in S. aureus. Out of 50 isolates of S. aureus from UTI patients, 36 (72%) were found to be MRSA by oxacillin screen agar. All these MRSA strains were found to be positive for mecA genes, 9 (25%) were found to be positive for PVL and 23 (64%) were positive for both icaA and icaD genes. MRSA isolated from UTI patients show the presence of mecA, PVL, ica genes, which may have consequences for the treatment of UTIs especially in catheter-associated and nosocomial infections. Key words: Urinary tract infections (UTIs), mecA gene, PVL gene, ica gene, MRSA.