جستجوی مقالات مرتبط با کلیدواژه « methicillin resistance » در نشریات گروه « پزشکی »

Methicillin-resistant staphylococci (MRS) are regarded as a global public health threat. Physicians are restricted in their treatment options due to resistance to aminoglycosides and tetracycline derivatives. This study investigated aminoglycoside and tetracycline derivative resistance among Staphylococcus isolates in Shiraz, southwestern Iran.

Totally, 113 staphylococcal isolates were recovered from different clinical samples in Nemazee Teaching Hospital from October 2019 to January 2020. Kirby-Bauer disc diffusion method was performed to assess the antimicrobial susceptibility of the isolates against aminoglycoside and tetracycline antibiotics. Aminoglycoside-modifying enzymes (AMEs) and tet genes were investigated among staphylococci isolates using polymerase chain reactions (PCR).

MRS prevalence among Staphylococcus isolates was 61% (69 of 113). The majority of MRS isolates were obtained from blood (39.1%; 27 of 69) and urine (17.4%; 12 of 69). The highest prevalence of MRS isolates was among emergency room patients (34.8%; 24 of 69). The highest resistance of MRS isolates was against tobramycin (59.4%; 41 of 69) and tetracycline (55.1%; 38 of 69). The prevalence of tetM and aac (6')-Ie-aph (2'') genes was significantly higher among MRS compared with methicillin-sensitive staphylococci (MSS) (87.5% vs 12.5% and 95.6% vs 6.4%, respectively) (p= .001).

The prevalence of MRS isolates, including methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS), was remarkable in Shiraz as the center of medical services in the southwest of Iran. Furthermore, these MRS isolates were highly resistant to aminoglycosides and tetracyclines. Therefore, antimicrobial stewardship is necessary to address health conditions.

 Methicillin Resistance Staphylococcus aureus (MRSA) causes staph infections, produces numerous toxins and virulence factors, and displays antibiotic resistance. Therefore, this study aimed to detect MRSA and its antibiotic-resistant patterns and evaluate the toxins genes in S. aureus isolates from Baghdad, Iraq.

 Two hundred twenty bacterial samples were collected from different clinical sources in Iraq, 2022-2023. The diagnosis was made using traditional culture, microscopic examinations, and molecular diagnosis using the 16srRNA gene and mecA gene used for Methicillin Resistance detection. In addition, Antibiotic resistance patterns were detected using VITEK-2. Also, the toxins genes were determined by sequencing.

 Fifty isolates were identified as S. aureus, and the strains showed high resistance to Benzylpenicillin, Erythromycin, Oxacillin, and Clindamycin. PCR showed a prevalence of the mecA gene in methicillin resistance S. aureus isolates by 100%, while toxin genes that were present in S. aureus were LukD/E gene 50(100%), eta gene 50(100%), etd gene 47(94%), LukS/F gene 34(68%) and tst gene 21(42%). All isolates tested negative for the etb gene. The results of the sequencing analysis of the studied genes showed that there were no genetic mutations. They were 100% identical except for the eta gene, and the results indicated three genetic mutations.

 All S. aureus isolates had the mecA gene for methicillin resistance, and S. aureus possessed toxin genes. The sequencing analysis of the eta gene indicated the presence of various mutations, including the silent mutations.

Staphylococcus haemolyticus is well known coagulase-negative staphylococci (CoNS). it is generally exist as a microbiota on skin. Internstigly, S. haemolyticus is generally considered as an opportunistic bacterial infections that highly associated with immunocompromised individuals, especially those who are hospitalized or have medical implants. S. haemolyticus is ranked as highly resistant pathogen to various types of antibiotics for both traditional and last line antibiotics including penicillins, tetracyclines, cephalosporins, macrolides, aminoglycosides, and quinolones and glycopeptides.

Isolates were identified using Gram-stain and several conventional biochemical test like oxidase, catalase, types of hemolysis, and coagulase tests. Vitek®2 system was utilized to confirm the results of identification. Methicillin resistance and inducible clindamycin resistance were detected according to disk diffusion method depending on CLSI guidelines, Moreover, molecular approaches was performed to confirm methicillin and inducible clindamycin resistance results.

200 swabs were collected from pateints with surgical wounds during the period From September to November 2020. Among 75 (37.5%) samples that showed positive bacterial cultures, 19 (25.3%) isolates of Pseudomonas aeruginosa revealed higher bacterial values followed by Staphylococcus epidermidis 13(17.3%),Staphylococcus aureus11(14.7%),…

D test and molecular technique for detecting inducible clindamycin resistance should be used as a routine work of antibiotic susceptibility testing, for the more accurate result to use the suitable antibiotic and avoid frailer treatment.

This study aimed to assess the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from community-acquired (CA) and hospital-acquired (HA) infections in Bandar Abbas, southern Iran.

This descriptive cross-sectional study was conducted on 110 S. aureus strains isolated from 59 outpatients and 51 inpatients during 2018-2019. Antimicrobial susceptibility testing was performed using disc diffusion method. Epsilometer test was used to measure vancomycin minimum inhibitory concentration (MIC). Cefoxitin disc (30 μg) was used to screen MRSA isolates. The presence of mecA gene was examined by PCR method.  Staphylococcal cassette chromosome mec (SCCmec) types were detected in S. aureus isolates using multiplex-PCR. Chi-square and Fisher's exact tests were used to analyze the results.

Out of 110 isolates, 45 (40.9%) isolates carried the mecA gene: 20 (39.2%) isolates from inpatients and 25 (42.4%) isolates from outpatients. MRSA isolates showed the highest resistance to azithromycin (69.8%), tetracycline (60.4%), and clindamycin (32.1%), respectively. Vancomycin MIC against MRSA isolates ranged from 0.75 to 5 μg/mL. SCCmec type I, III, IV, and V were detected in 20 (44.4%), three (6.7%), 16 (35.5%), and six (13.3%) isolates, respectively.

The predominant SCCmec types were type I and type IV, which were detected in CA- and HA-MRSA isolates, respectively. No significant difference in the presence of SCCmec type III and antibiotic resistance was found between CA- and HA-MRSA isolates, indicating the possibility of cross-infection between these isolates. Developing appropriate treatment protocols to prevent the spread of MRSA infections in the community is currently an urgent need.

To analyze the microbiological spectrum and antibiotic sensitivity patterns in children with congenital nasolacrimal duct obstruction (CNLDO).

One hundred thirty‑four eyes of 123 children in the age group of 0–16 years with a diagnosis of CNLDO who underwent lacrimal surgical procedures were included in this prospective comparative study. Sixty‑two children in the age‑matched group planned for intraocular surgery with patent nasolacrimal duct were deemed controls. The conjunctival swab after performing Regurgitation on Pressure over the Lacrimal Sac in the CNLDO group and the conjunctival swab in controls were sent for microbiological analysis. Antibiotic susceptibility testing was done for commonly employed antibiotics by the Kirby Bauer disk diffusion method.

Of 134 samples collected in the CNLDO group, 111 (82.8%) samples were culture positive. There were 165 bacteria isolated, among which 139 (84.24% of isolates) were Gram‑positive bacteria, and 26 (15.75% of isolates) were Gram-negative. Fungal isolates were obtained in 2.23% of cases. The most common Gram‑positive isolate was Staphylococcus epidermidis (S. epidermidis) (n=51, 30.9% of total isolates), and the most common Gram‑negative isolate was Haemophilusinfluenza species (n = 9, 5.5% of total isolates). Gram‑positive isolates were sensitive mostly to gentamicin and vancomycin (95.5% each), and Gram‑negative isolates to amikacin (92.3%). Both Gram‑positive and Gram‑negative isolates were susceptible to gatifloxacin (80% each). Probing outcomes were similar among Gram‑positive (success, 84.6%) and Gram‑negative (success, 84.0%) organisms.

There was a predominance of Gram‑positive isolates in children with CNLDO with S. epidermidis being the most common. The microbiological profile did not have any effect on the outcomes of probing

Recently, the rise of methicillin-resistant Staphylococcus aureus (MRSA) isolated from hospital healthcare workers (HCWs) and various infectious samples has become one of the main concerns in hospital settings. Therefore, epidemiological studies are necessary to monitor antibiotic resistance patterns in each region and to study the pathogenesis of this strain to control infections.

In this cross-sectional study, a total of 100 S. aureus isolates, including 50 isolates obtained from the anterior nares of healthcare workers, as well as 50 other isolates cultured from the various clinical specimens from the referral hospitals in Khorramabad (West of Iran) were tested. All isolates were examined to determine antibiotic resistance pattern, and the presence of staphylococcal enterotoxin A (sea), staphylococcal enterotoxin B (seb) and mecA genes.

The mecA gene was found among 36% (18/50) of the clinical S. aureus isolates (CSIs) and 14% (7/50) of nasal S. aureus isolates (NSIs), with statistically significant difference (X2 = 6.53; p = 0.011). The difference between the frequency rate of sea gene among MRSA strains isolated from clinical specimens (46.6%, 7/15) was significant compared to strains isolated from nostrils (14.3%, 1/7) (X2 = 3.85; p = 0.049).

The frequency of mecA, sea, and seb genes among the clinical samples was more than strains isolated from the nostrils of healthcare personnel.

 Recent studies have shown an increasing incidence of antibiotic resistance in dacryocystitis. Management of diseases may include determining microbial agents and choosing appropriate antibiotics for treatment.

 This study aimed to present the best treatments for dacryocystitis. To this end, specimens' microbiology and antibiotic susceptibility were examined in patients with dacryocystitis in the microbiology laboratory of the Kashan University of Medical Sciences.

 This cross-sectional study was performed on 172 patients presenting with acute and chronic dacryocystitis at the Matini Hospital, Kashan, between 2017 - 2018. Patient characteristics, culture isolates, and antimicrobial susceptibility data were collected. The PCR assay of the mecA gene was performed in all methicillin-resistant Staphylococcus isolates.

 The most common bacteria were coagulase-negative staphylococci (CoNS), Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii. The majority of the isolated microbes were sensitive to rifampicin, linezolid, amikacin, and gentamicin. In Gram-negative bacilli, nine of the isolates were extended-spectrum beta-lactamase positive. The PCR test showed the frequency of mecA gene of resistant S. aureus and resistant CoNS isolates to be 40 and 46.3%, respectively.

 Coagulase-negative staphylococci were the most frequently isolated bacteria. The highest antibiotic susceptibility was observed to rifampin, linezolid, amikacin, and gentamicin. A high percentage of CoNS carried the mecA gene.

Staphylococcus intermedius group (SIG), a known veterinary pathogen with the potential for zoonotic human infections, comprises S. intermedius, S. pseudointermedius, and S. delphini, which are not easily distinguishable. Without the proper equipment and procedures, it cannot be distinguished from Staphylococcus aureus (SAu), which causes underestimation of its true incidence.

A 52-year-old male with diabetes presented with complaints of fever and malaise. He developed respiratory failure and altered mental status; hence, intensive care was provided to him. Blood cultures and bronchoalveolar lavage culture developed methicillin-resistant SIG. Despite rapid adjustment of empiric antibiotic therapy, he died of multiple organ failure.

Incorporating knowledge about this new pathogen and its aggressiveness into daily clinical practice can, through a high index of suspicion and detailed anamnesis, reduce misdiagnoses.

AThe aim of this study was to evaluate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization in the health care workers of emergency department of Imam Reza hospital, Tabriz, Iran

In a total of 63 physicians and nurses in the emergency department of Imam Reza hospital, after obtaining written consent and completing a checklist, a sample of nasal mucosa was collected for microbiological examination and isolation of Staphylococcus aureus (SA) strain. Determination of resistance patterns (by diffusion method) was performed according to the standard methods of methicillin.

Out of 63 participants, 8 subjects (12.7%) had colonization of S. aureus; 4 of them were physicians (17.3% of the participated physicians) and 4 were nurses (10% of the participated nurses). Out of 8 isolated SA, 2 cases (25%) and overall 3.1% were methicillin-resistant. In our study, there was a significant relationship between co-employment in other hospitals and patient care at home with SA colonization, but there was not a significant relationship with specialty, work experience, sinusitis, history of antibiotic use, history of skin disease, hand washing habits and use of personal protective equipment.

Prevalence of MRSA was not high among health workers of emergency department.

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious concern of the global health sector and more recently, an escalating problem in the community. This study was performed to investigate the incidence of MRSA in hospital staff and community students in Duhok, Kurdistan, Iraq, and make a molecular comparison between the strains based on the detection of mecA gene and Panton-Valentine Leukocidin (PVL) gene. We obtained 109 and 103 samples from the nares of hospital staff and community students, respectively. Conventional laboratory tests were performed for the detection of Staphylococcus aureus (S. aureus) and antibiotic sensitivity testing to identify MRSA isolates. Besides, PCR was utilized for molecular analysis. All isolates from hospital staff were identified as S. aureus. Out of the 109 isolates, 55 (50.4%) were MRSA carrying the mecA gene, among which 4/55 (3.7%) were MRSA-PVL positive. Additionally, 54/109 (49.5%) isolates were methicillin-sensitive S. aureus (MSSA) but four isolates (3.7%) were MSSA-PVL positive. Furthermore, 23/103 (22.3%) samples from community students were identified as S. aureus, among which 5/23 (21.7%) and 17/23 (73.9%) isolates were MSSA-PVL positive and MSSA-PVL negative, respectively. Moreover, 1/23 (4.3%) was found as MRSA and was PVL gene-positive. The results showed that MRSA is swarming in hospitals and community in Duhok, Iraq. The highest rate of PVL was associated with community-acquired-MSSA (CA- MRSA). With further genotypic study, immediate action is needed to control and reduce the spread of MRSA clones, determine their clonal relations, and conduct epidemiological investigations.

  Staphylococcus aureus is a gram positive pathogen which causes a wide range of infections. The present study aimed to investigate genotypic and phenotypic screening about biofilm formation in S. aureus isolated from wound infections in a diabetes clinic in Hazrat Fatemeh Zahra (SA) hospital. A total of 267 clinical samples were collected from various types of wound infections in the diabetes clinic of Hazrat Fatemeh Zahra (SA) hospital, Isfahan, Iran. The methicillin-resistant S. aureus (MRSA) isolates were selected and biofilm formation and its related genes were analyzed by polymerase chain reaction (PCR). The results showed that 95 out of 132 samples were MRSA. The high resistance was seen to methicillin, erythromycin, ciprofloxacin, and penicillin. Phenotypic results showed that 48.3% of the isolates were high biofilm producers, 29.1% were average biofilm producers, and 10.6% were low biofilm producers. According to the results of this study, the expression levels of biofilm-associated genes significantly increased, and high prevalence of antibiotic resistance was one of the important reasons for the development of drug resistance in patients.

Given the prevalence of methicillin-resistant Staphylococcus aureus infections and the importance of antibiogram pattern in the treatment of these infections, the present study aimed to evaluate the methicillin and vancomycin resistant Staphylococcus aureus clinical isolates.

S. aureus isolates were diagnosed using proprietary cultivation environments and standard biochemical methods by isolating 130 Staphylococcus samples from patients’ clinical specimens. The isolates antibiotic susceptibility pattern was determined by disc diffusion method. MRSA isolates were identified using cefoxitin discs, and the E-test method was used to determine the minimum inhibitory concentration (MIC) of vancomycin antibiotic. Furthermore, the multiplex PCR method was used to study the frequency of mecA and vanA genes.       

In the present study, 57 out of 130 Staphylococcus isolates were diagnosed as S. aureus. According to the antibiogram test results, the isolates showed the highest resistance to penicillin (92.98%) and the lowest resistance to ciprofloxacin (10.52 %). In addition, the resistance to methicillin was reported as 21.56 % using cefoxitin disc.  According to the E-test results, 90% of the isolates were susceptible to vancomycin, and 10% showed heterogeneous resistance to vancomycin. The molecular analysis indicated that mecA gene was present in 35.08% of the isolates, but no isolate contained vanA gene.

Despite the lack of resistance to vancomycin, the isolates showed a high resistance to methicillin. Therefore, the present study results emphasized the necessity of performing antibiotic sensitivity tests before the drug administration.

Methicillin resistant Staphylococcus aureus (MRSA) strains are a major contributor to the development of hospital- and community-acquired infections. The aim of this study was to evaluate the polymorphism of mecA gene, frequency of blaZ gene, and detection of mecA promoter mutations in clinical isolates of methicillin-resistant S. aureus strains. Susceptibility of 85 S. aureus clinical strains to methicillin was evaluated using disc diffusion method. The polymorphism of mec-associated hypervariable region (HVR), presence of blaZ genes, and mutation in mecA promoter were determined by PCR and sequencing. A total of 40 (47.1%) out of 85 S. aureus isolates were identified as methicillin resistant by phenotypic assays and PCR-based detection of mecA gene in MRSA strains. Seven different groups of repeats were found among these strains. Also, 39 MRSA strains harbored blaZ gene, and according to the sequence analysis of mecA promoter, R226S mutation was identified in 1 out of 10 isolates tested. According to the obtained results, there was a high variation in the polymorphic region of mecA gene in clinical isolates of S. aureus. In addition, it was appeared that beta-lactamase enzyme production and antibiotic hydrolysis played an important role in the occurrence of resistance to beta-lactam antibiotics, and the effect of mutation in genes regulating mecA gene expression was negligible.

Otitis is a general terminology used for inflammation or infection of the ear; Staphylococcus aureus and Pseudomonas spp. are the most common causes of otitis externa. The resistance mechanism against the beta-lactams group is due to the production of β-lactamase enzymes by the bacteria; the enzymes in staphylococci are encoded by erm genes that confer inducible Clindamycin resistance.
This study aimed at investigating bacterial resistance by evaluating samples collected from Otitis Externa patients admitted to Ayatollah Roohani Hospital of Babol, Iran.
Ear samples were collected from 72 patients with Otitis Externa referred to Ayatollah Roohani hospital during May 2012 to 2013. At first, the isolated bacteria were identified using appropriate differential and selective media, and then were tested for antimicrobial susceptibility testing following the disk diffusion method. Special diagnostic tests were also performed for the identification of ESBL, iAmpC, pAmpC, metallo beta lactamase producers and inducible resistance to clindamycin and methicillin resistant strains. Data were analyzed by the SPSS 22 statistical software.
Among the 65 isolated bacteria, 24 (36.9%) cases were found to be gram negative and 41 (63.1%) were gram positive; pAmpC beta-lactamase producers were found to have the highest frequency in gram negative bacteria. From 36 (87.8%) isolated CoNS, 18 (50%) bacteria were found to be resistant to the methicillin group and 4 (11.1%) cases had inducible resistance to clindamycin; All isolated S. aureus were sensitive to methicillin and clindamycin.
Considering that some bacteria are concurrently able to produce different types of resistance enzymes, and also the fact that high prevalence rate of resistance belongs to CoNS, it is important and necessary to perform antimicrobial susceptibility testing as per clinical and laboratory standards institute (CLSI) methods in clinical laboratories.