فهرست مطالب mohammad motamedifar

Staphylococcus aureus (S. aureus) is responsible for most cases of food poisoning all around the world. These carriers and manipulated foodstuffs are the main sources of bacteria transmission to ready-to-eat food. This study aims to determine the genetic affinity of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from cream pastries and workers, nasal of Shiraz city confectioneries.  

30 MRSA strains (7 nasal carriers, 23 food isolates) were selected from the bank of bacteria at Shiraz medical faculty. To determine the genetic affinity of the isolates, RAPD-PCR technique was performed using OLP6, OLP11, and OLP13 primers. RAPD-PCR patterns were analyzed using the software GelJ.

By using primer OLP6 only 5 RAPD-PCR patterns were produced from DNA ampliqons of creamy pastry isolates and were not enough to compare the genetic affinity of all the isolates. Based on 100% similarity, OLP13 primer produced 20 different patterns with some bands in the range of 1 to 11, and the OLP11 primer produced 22 patterns with some bands from 3 to 11 bands. At closely and possibly genetically related levels, the isolates are categorized into (13-15) and (1-5) clusters. In general, all the isolates are classified into human and food isolates.

There was no genetic affinity of MDSA isolates regarding human and food samples; but, a high percentage of close genetic relationship between the isolates increases the possibility of bacteria transfer from humans to pastries and food poisoning

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.

Septic arthritis (SA) or infectious arthritis (IA) typically occurs following hematogenous inoculation of pathogenic organisms in susceptible individuals. This infection is commonly a result of hematogenous spread of the infectious agent, inflammation or bone infection dissemination, as well as trauma or surgery. Early diagnosis and treatment of SA are crucial for affected patients.

This retrospective study aimed to investigate the prevalence of bacterial SA and the trend of antibiotic resistance in a specialized orthopedic and neurosurgery hospital from 2018 to 2020.

Patient records from the hospital admissions between 2018 and 2020 were reviewed. Data including patient age, gender, hospital ward, and antibiotic susceptibility test results were extracted and recorded for analysis. Statistical analysis was performed using SPSS version 22 software.

Among the 249 cases investigated, 29 positive bacterial cultures were reported (11.6%). The knee joint was the most commonly affected (48.3%), followed by the ankle (27.6%). The most frequently prescribed antibiotics were ciprofloxacin, cefazolin, and cephalexin, respectively. Over the three-year study period, an increase in antibiotic resistance to ciprofloxacin and cefazolin and a decrease in antibiotic resistance to cephalexin were observed.

Despite its common occurrence, diagnosing SA can be challenging. Early joint surgery (arthrotomy) along with the initiation of effective antibiotic therapy plays a crucial role in reducing the incidence of complications associated with this disease.

Urinary tract infection (UTI) is one of the most common bacterial infections of all ages and sexes. Escherichia coli is reported as the most common predominant pathogen. Urinary tract infection treatment leads to abundant antibiotic application in hospitals and communities, continuously developing multidrug resistance (MDR). This study aimed to determine the sensitivity and resistance pattern to common antibiotics among E. coli isolates from patients with UTIs at Nemazee Hospital in Shiraz.

This retrospective cross-sectional survey studied 1910 positive urine samples with E. coli bacteria from patients referred to Nemazee Hospital from 2018 to 2019. Antimicrobial susceptibility testing was performed on 12 commonly used antibiotics for UTIs.

A total of 1910 E. coli isolates were gathered during these 2 years. The most highlighted resistance was observed against quinolones and cephalosporins at 86.9% and 89.7%, respectively. Cephalexin (87.9%) and nalidixic acid (86.1%) have shown the lowest activity against E. coli isolates. Also, the highest susceptibility was determined for amikacin (88.3%), nitrofurantoin (76.8%), and gentamicin (70.6%). In addition, 1624 (85%) isolates were MDR.

In conclusion, resistance to antibiotics (such as ciprofloxacin, norfloxacin, tetracycline, cefotaxime, and nitrofurantoin) is increasing. Therefore, it is vital to follow an appropriate antimicrobial stewardship program.

Ox-bile has been recommended as a natural remedy with several therapeutic potentials in traditional Persian medicine. It has had efficacy against inflammation and infection according to traditional medicine. Evidence revealed that bile disrupts bacterial cell membrane and degrades DNA structure, so it has anti-bacterial effects. However, there is no evidence of any approved medication composed of ox-bile in Iran.

The aim of this study was to evaluate the in vitro anti-bacterial effects of ox-bile.

Ox-bile was obtained under aseptic conditions and sterilized with a 0.22 msyringe filter, then examined for their sterility status through culture on different media. Following incubation under aerobic cultures for 48 hours and the anaerobic cultures for one week. Two different kinds of antimicrobial susceptibility tests, including well-diffusion method and serial dilution test were employed to characterize the inhibitory effect of ox-bile extraction on Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Propionibacterium acnes.

Based on our study, no anti-bacterial effect of ox-bile was observed against selected gram-positive and gram-negative bacteria.

No in-vitro evidence of inhibitory effect was observed against studied gram-positive and gram-negative bacteria. Though further evaluation of the anti-bacterial effects of different preparations of ox-bile seems is still required.

Pasteurella multocida a Gram-negative bacterium exists as a commensal in the upper respiratory tracts of livestock, and poultry. It is causative agent of a range of diseases in mammals and birds including fowl cholera in poultry, atrophic rhinitis in pigs and bovine hemorrhagic septicemia in cattle and buffalo. This study aimed to isolate P. multocida from sheep and cattle lungs sampled and assessed by bacteriological procedures and pulse field gel electrophoresis (PFGE) characterization. In this study 52 isolated of P. multocida were obtained (2016-2017) from clinically healthy and diseased animals (sheep and cattle) evaluated by PFGE for determining the relationship between them. According to the results of this study 12 sheep isolates had similarities above 94.00% and two cattle isolates showed similarities above 94.00%. When compared between sheep and cattle, most isolates showed a similarity of less than 50.00% indicating the great differences between isolates. It is noteworthy that in the present study, performed by PFGE to determine the type of P. multocida isolates, a very high distinction was made to determine the type of isolates and the relationship between isolates based on fragments in their genome using enzymes.

Staphylococcus aureus is responsible for the majority of food poisoning all around the world. Nasal carriers of S. aureus and foodstuffs need for handling are important sources and vehicles to transmit this pathogen to ready-to-eat foods. According to hygienic standards, confectioners should not be contaminated with S. aureus. This study aimed to detect nasal carriers and creamy pastries contaminated with enterotoxigenic S. aureus in confectioneries of Shiraz, Iran.

From the confectioneries of Shiraz city, 27 places in the north, south, center, west, and east areas were selected randomly then 100 creamy pastries samples and 117 nasal swabs were collected. Bacteriological and biochem- ical tests were performed to isolate S. aureus. The polymerase chain reaction (PCR) test was used to identify the virulence and enterotoxins genes of the S. aureus isolates. Agar disk diffusion was performed to find out the antibiotic resistance of the isolates.

Results revealed that 16.24 and 33 percent of workers and creamy pastries were contaminated with S. aureus respec- tively. Also, 100%, 37%, 58%, and 6% of nasal samples harbored femA, mecA, sea, and sec genes respectively. According to the results 97%, 70%, 54.5%, and 6% of creamy pastries isolates harbored femA, mecA, sea, and sec genes respectively. No isolate carried seb and sed genes. The results also showed that 41.5% of nasals and 5.5% of creamy pastry isolates har- bored both sea and sec genes. The sea was the most common enterotoxin gene observed in nasal and creamy pastries. The results of the antimicrobial resistance test showed that 68.42% of nasal and 48.48% of creamy pastry isolates were resistant to cefocxitn (FOX) respectively. Both nasal (89%) and creamy pastry (82%) isolates presented the highest resistance to pen- icillin (P) and the most sensitivity to trimethoprim-sulphamethoxazole (SXT) (94%). Most of the isolates were sensitive to erythromycin (E), aztreonam (AZM), tetracycline (TE), trimethoprim (TMP), and ciprofloxacin (CP). Isolates of S. aureus harboring multi-enterotoxin genes were resistant to more antibiotics than others.

The presence of enterotoxigenic S. aureus in the workers’ nasal samples and creamy pastries of Shiraz confec- tioneries was high which is a potential public health hazard.

Fetal abortion is one of the critical and controversial issues in most societies’ scientific, social, and academic ceremonies due to known and unknown reasons. Furthermore, updating our knowledge about isolated bacteria, their antibiotic resistance pattern, and related factors is essential for designing and implementing appropriate interventions.

The current study was conducted to determine the prevalence of bacteria among fetal abortion cases and demonstrate the antimicrobial susceptibility among isolated bacteria.

For this, 153 blood samples were collected percutaneously from the heart blood of aborted fetuses 1 - 15 hours after birth; subsequently, the identification of bacteria and evaluation of antimicrobial susceptibility testing were performed.

Generally, 82 out of 153 test cultures were positive, comprising 66 and 26 Gram-negative and Gram-positive bacteria, respectively. The most isolated bacteria among Gram-negative isolates were Acinetobacter spp. (34/82) and Escherichia coli (17/82). Likewise, the highest antibiotic resistance was detected for Acinetobacter spp. against cefixime, amikacin, gentamycin, and ciprofloxacin (24/34). On the other hand, Staphylococcus spp. was the predominant Gram-positive cocci (10/82). Also, the highest resistance for Staphylococcus spp. was against cefoxitin and ciprofloxacin (100%).

It seems more focus on following the general hygiene of pregnant mothers is essential. However, further evidence of a clinical correlation between aborted fetuses and their mothers is required.

 Systemic sclerosis is an autoimmune disorder with orofacial manifestations, including tooth decay. Lactobacilli can inhibit biofilm formation and growth of cariogenic pathogens, such as Streptococcus mutans. We aimed to assess the salivary levels of S. mutans and Lactobacilli as indicators of dental caries development in patients with systemic sclerosis.

 In this cross-sectional study, 80 patients with systemic sclerosis were assigned into 2 groups, anti-centromere antibody (ACA) positive (n=42) and ACA-negative (n=38). Besides, 80 age- and gender-matched healthy individuals were enrolled as control. Unstimulated saliva was collected in sterile tubes. Blood agar and tomato juice agar were used to cultivate S. mutans and Lactobacilli. The number of colony-forming units per milliliter (CFU/mL) was calculated and compared between the groups.

 S. mutans in patients (median=1.6×107 CFU/mL; interquartile range (IQR): 1.1–3.1 ×107 CFU/mL) was significantly higher than control group (median=5.1×106 CFU/mL; IQR: 5.1–7.9 ×106 CFU/mL) (P<0.0001, Mann-Whitney U-test); however, the median Lactobacilli levels was similar between these groups (3.4×106 vs. 2.2×106 CFU/mL; P=0.095). The median concentrations of S. mutans (1.3×107 vs. 2.4×107 CFU/mL; P=0.342) and Lactobacilli (4.1×106 CFU/mL vs. 3.1×106 CFU/mL; P=0.515) in the ACA-positive and ACA-negative patients had no significant differences. There were no significant correlation coefficients between S. mutans and Lactobacilli levels in the study groups (P>0.05).

 Our findings suggest the higher levels of salivary S. mutans in patients with systemic sclerosis might increase the likelihood of dental caries over time; however, it was not affected by the ACA status.

Acinetobacter baumannii is a global concern that causes healthcare-associated infections due to multidrug resistance against commercially available antimicrobial agents.

The present study was conducted to determine the antimicrobial susceptibility of A. baumannii isolates from clinical specimens in Shiraz, Iran. In addition, the possible relationship of susceptibility patterns with the presence of integrons and related gene cassettes is investigated.

Acinetobacter baumannii isolates were collected, and their susceptibility to various antibiotics was tested using the Kirby-Bauer disk diffusion method. Moreover, molecular analysis were performed to detect the presence of the OXA-51-like gene, as well as class I, II, and III integrons, and associated gene cassettes.

The majority of isolates were resistant to imipenem (99.4%), piperacillin (98.2%), gentamycin (98.2%), meropenem (97.7%), ceftazidime (95.4%), amikacin (95.4%), and trimethoprim-sulfamethoxazole (90.8%). All strains showed multidrug resistance to the tested antibiotics. The distribution analysis of integrons genes revealed that 90.2, 72.4, and 12.1% of the isolates carried intI1, intI2, and intI3 genes, respectively. Moreover, two types of prevalent gene cassettes, including aad and dfr, were detected in class 1 integron-carrying strains.

The current study showed the high prevalence of A. baumannii isolates harboring integrons in our investigated medical center, which may indicate the distribution of multidrug resistance events. The different gene cassette arrays highlight the remarkable role of geographical issues in disseminating multidrug-resistant (MDR) isolates. This could be attributed to distinct therapeutic interventions in different areas. The results demonstrate the necessity of continuous surveillance to prevent the distribution of multidrug resistance among A. baumannii strains in Iran.

In recent years, Acinetobacter baumannii has attracted the research community’s attention since they are turned into the leading cause of both community- and hospital-acquired infections. The emergence of MDR-A. baumannii strains threatens hospitalized patients since antibiotics fail to withdraw the bacterial infectious agents. Despite its worldwide distribution, health settings fail to combat limitations in therapeutic regions against A. baumannii. The capability of biofilm formation in A. baumannii strengthens their virulence and also survival. Understanding the fundamental virulence mechanisms beyond the microbial aggregations leads to exploring alternative drug targets such as signaling molecules and Quorum sensing systems to block bacterial communication and antimicrobial resistance. The significance of examining the biofilm’s structural details and the relationship between Quorum sensing networks and related signaling molecules has been explicitly highlighted. Accordingly, this review study aimed to explain the general biofilm structure, the mechanisms beyond biofilm formation, quorum sensing system, and the generation of signaling molecules in A. baumannii.

About 8-12% of couples on reproductive age suffers from infertility worldwide. Since 1993, the role of genital tract infections by microbes, including viruses that can infect the sperm, in human infertility has been proposed.

To investigate the frequency of hepatitis B virus (HBV), human papilloma virus (HPV), Epstein-Barr virus (EBV), and herpes simplex virus (HSV) infection in the semen of fertile and infertile men referred to the Mother and Child Hospital, Shiraz, Iran.

In this cross-sectional study, 350 men including 200 infertile and 150 fertile men were included. All semen samples were allowed to liquefy, followed by the assessment of sperm parameters. DNA was extracted using a DNA extraction kit (CinaGene, Tehran, Iran) according to the manufacturer’s instructions. Detection of HBV, HPV, EBV, and HSV1/2 was done by the PCR method.

The mean age of the participants was 36 ± 7 yr. Molecular results showed that 16 samples (8%) of infertile men and 5 (3.3%) of fertile men were positive for HBV, which was not statistically significant (p = 0.069). Only one sample of the fertile participants was positive for HPV. None of the semen samples of the infertile or fertile groups was positive for the presence of EBV or HSV1/2.

The results of this study indicated that HBV, HPV, EBV, and HSV might not be involved in men’s infertility. Further studies are recommended for clarifying the role of these viruses in infertility.

 Ventilator-associated pneumonia (VAP), a subset of hospital infections, occurs in patients who have been mechanically ventilated for at least 48 hours.

 Our study aimed at determining the frequency and antibiotic susceptibility patterns of bacteria causing VAP in teaching hospitals of Shiraz.

 This was a descriptive cross-sectional study conducted in Shiraz for eight months (November 2017 to June 2018). Samples were detected according to diagnostic bacteriologic tests, and antibiotic susceptibility tests were performed by the disk diffusion (Kirby-Bauer) method based on the Clinical and Laboratory Standards Institute (CLSI).

 A total of 51 patients with VAP were examined, of whom 10 and eight patients had a chronic obstructive pulmonary disease and acute respiratory distress syndrome, respectively. The late-onset VAP rate (61.7%) was higher than the early-onset VAP rate (38.3%). In our study, 45.2% of patients with VAP received antibiotics before the incidence of pneumonia, of whom 31.6% died. Of the remaining 54.8%, only 8.7% died. In other words, patients who received antibiotics before the incidence of pneumonia had higher mortality. The most frequently used antibiotics were meropenem (76.6%) and vancomycin (78.7%). Among 59 bacteria isolated, Acinetobacter and Pseudomonas were the most prevalent organisms.

 Our results showed that most of the isolates (40%) belonged to multi-drug resistant (MDR) pathogens. Probably, antimicrobial treatment before the onset of VAP led to the selection of these MDR pathogens.

Prompt detection of extended-spectrum β-lactamases (ESBL) and carbapenemase-producing enterobacteriaceae is crucial for infection prevention and control strategies. The present study aimed to characterize the ESBL and carbapenemase genes among Enterobacter isolates from an Iranian inpatient population. A total of 96 Enterobacter isolates obtained from inpatients between June 2016 and March 2017, were identified by the conventional microbiological methods and diagnostic kits. Antimicrobial susceptibility pattern was performed using the disk diffusion method. The ESBL and carbapenemase genes were screened using polymerase chain reaction (PCR). All clinical isolates of Enterobacter were classified as E. gergoviae (52, 54.2%), E. aerogenes (34, 35.4%), E. cloacae (7, 7.3%), Cronobacter (E). sakazakii (3, 3.1%). The highest and lowest antimicrobial resistance rates were observed against ampicillin (93.8%) and imipenem (21.9%). High prevalence of multi-drug resistance (MDR=96.9%) was substantial. Of the 96 Enterobacter isolates, 35 (36.5%) and 28 (29.2%) were phenotypically ESBL-positive and non-susceptible carbapenem, respectively. Overall, the frequency of evaluated genes was as follows: blaCTX-M =25 (26%), blaTEM =30 (31.3%), blaSHV =12 (12.5%), blaIMP =3 (3.1%), blaVIM =0 (0%), blaNDM =8 (8.3%), and blaKPC =0 (0%). In this study, we report for the first time the presence of E. gergoviae harboring blaNDM from an Iranian population. Regarding the increase of MDR Enterobacter spp. in our region, strict hygiene rules will be needed to control the quick spread of ESBL and carbapenemase-producing Enterobacter isolates in healthcare facilities of developing countries.

We aimed to investigate antimicrobial resistance and clonal relationships among poultry Escherichia coli isolates from different broiler farms and their relationships with Extended-Spectrum Beta-Lactamase (ESBL) producing urinary pathogenic E. coli (UPEC) isolates from the same geographical area.

Twenty four E. coli isolates from six broiler farms with colibacillosis and 97 ESBL producing human UPEC isolates were investigated for resistance to critically important antimicrobials in human medicine in Shiraz, central Iran in 2015-16. In addition, clonal relationships of these isolates were investigated with Pulse Field Gel Electrophoresis (PFGE).

As expected, cephalosporins and imipenem resistance were significantly higher in ESBL producing human E. coli isolates in comparison with non-ESBL avian pathogenic E. coli (APEC) isolates. In addition, significantly higher percentages of gentamycin and trimethoprim-sulfamethoxazole resistance were seen in human isolates. In contrast, nitrofurantoin resistance was significantly higher in APEC isolates. Based on PFGE patterns, five clusters were identified in APEC isolates. Isolates from each farm were closely related to each other by PFGE patterns. However, different PFGE restriction profiles were seen among the E. coli isolates from different broiler farms. Comparison of PFGE patterns among APEC and UPEC isolates showed two closely related PFGE patterns.

There were clonally related E. coli isolates caused the outbreaks of colibacillosis within broiler farms. Some of these isolates had closely related PFGE patterns with human UPEC isolates which suggest avian pathogenic E. coli strains as a potential zoonosis.

Stenotrophomonas maltophilia has emerged as an important opportunistic nosocomial pathogen due to its intrinsic and acquired resistance to a wide range of antimicrobial agents. The present study aimed to investigate the occurrence of antibiotic resistance and resistance mechanisms among clinical isolates of S. maltophilia from Iranian patients. This cross-sectional study was performed on 44 S. maltophilia isolates that were recovered from different clinical specimens in 2015 and 2016. Conventional microbiologic methods were used for primary identification of isolates and confirmed by specific polymerase chain reaction (PCR) primers. Minimum inhibitory concentrations (MICs) were determined by the E-test. PCR was applied to determine antibiotic resistance genes. All of S. maltophilia isolates were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX) and colistin. Moreover, the susceptibility rates of isolates toward ceftazidime and ciprofloxacin were 93.2%, and 84.1%, respectively. Class 1 integrons was detected in 24 (54.5%) isolates by the presence of int1 gene. Moreover, the prevalence of antibiotic resistance genes sul1, sul2, and Smqnr were found in 16 (36.4%), 15 (34.1%), and 29 (65.9%) isolates, respectively. In summary, the prevalence of sul and Smqnr genes in integrons-contained isolates point out the significant risk of sulfonamides and fluoroquinolones resistance among clinical isolates of S. maltophilia in our region.

Although zinc oxide (ZO)-calcium hydroxide (CaOH) mixtures have been successful regarding their absorption rate compatibility with dissolving primary teeth, no study has been conducted on the appropriate mixture ratio to obtain effective antibacterial properties. In this study, we compared antibacterial activity of CaOH-ZO pastes using different mixture ratios sagainst Enterococcus faecalis as an important bacterium in root canal treatment failure. Seven types of pastes were prepared in our laboratory. The first group included one gram of ZO+eugenol, second group included one gram of CaOH+distilled water, third group included 0.5gram ZO+0.5gram CaOH+distilled water (1:1), forth group included 0.75gramCaOH+0.25gramZO+distilled water (3:1), the fifth group included 0.33gram of CaOH+0.66gram of ZO+distilled water (1:2), the sixth group included 0.75gram of ZO+0.25 CaOH+distilled water (3:1), the seventh group included 0.66 gram CaOH+0.33 gram ZO+distilled water (2:1), and the final group included one gram of gelatin+distilled water (as the control group). These pastes were compared regarding their antibacterial effects against Enterococcus faecalis using agar diffusion and microdilution methods. Except for the control group, all prepared pastes showed antibacterial properties. Order of minimum inhibitory concentration for pastes were as followed: CaOH-ZO (1:3)=CaOH-ZO (1:2)>CaOH-ZO (1:1)>CaOH-ZO (3:1)=CaOH-ZO (2:1)>CaOH=ZO-eugenol. Order of minimum bactericidal concentration, which shows a weaker bactericidal effect, according to type of paste, were as followed: CaOH-ZO (1:3)>CaOH-ZO mixture (1:2)>CaOH-ZO mixture (1:1)>CaOH-ZO mixture (3:1)=CaOH-ZO (2:1)>CaOH=ZO-eugenol. Only CaOH-ZO (1:3) and CaOH-ZO (1:2), showed significantly weaker MICs and MBCs (p < 0.001). Considering the limitations of an in-vitro study, in terms of anti-bacterial effects against Enterococcus faecalis, CaOH-ZO mixture (2:1) is equivalent to ZO-eugenol as the most commonly used material in polypectomy of primary teeth.

Clostridioides (Clostridium) difficile infection as a healthcare-associated infection can cause life-threatening infectious diarrhea in hospitalized patients. The aim of this study was to investigate the toxin profiles and antimicrobial resistance patterns of C. difficile isolates obtained from hospitalized patients in Shiraz, Iran. This study was performed on 45 toxigenic C. difficile isolates. Determination of toxin profiles was done using polymerase chain reaction method. Antimicrobial susceptibility to vancomycin, metronidazole, clindamycin, tetracycline, moxifloxacin, and chloramphenicol was determined by the agar dilution method. The genes encoding antibiotic resistance were detected by the standard procedures. The most frequent toxin profile was tcdA+, tcdB+, cdtAˉ, cdtBˉ (82.2%), and only one isolate harboured all toxin associated genes (tcdA+, tcdB+, cdtA+, cdtB+) (2.2%). The genes encoding CDT (binary toxin) were also found in six (13.3%) isolates. Resistance to tetracycline, clindamycin and moxifloxacin was observed in 66.7%, 60% and 42.2% of the isolates, respectively. None of the strains showed resistance to other antibiotics. The distribution of the ermB gene (the gene encoding resistance to clindamycin) was 57.8% and the tetM and tetW genes (the genes encoding resistance to tetracycline) were found in 62.2% and 13.3% of the isolates, respectively. The substitutions Thr82 to Ile in GyrA and Asp426 to Asn in GyrB were seen in moxifloxacin resistant isolates. Our data contributes to the present understanding of virulence and resistance traits amongst the isolates. Infection control strategies should be implemented carefully in order to curb the dissemination of C. difficile strains in hospital.

     Acinetobacter baumannii is one of the important causes of nosocomial infection worldwide. Patients who use ventilator are in high risk of ventilator association pneumonia (VAP) caused by nosocomial pathogens such as A. baumannii.  Carbapenem is one of the last lines of antibiotic therapy in MDR A. baumannii infections. Then, carbapenem resistant strains are a very important challenge for physicians. OXA types carbapenemase enzymes are important mechanisms to carbapenem resistance in A. baumannii. The aim of this study was to determine oxa-23 and oxa-48 producing A. baumannii isolated from VAP. 

      In this cross-sectional study, 51 sputum specimens from VAP in hospitalized patients in Hazrat-E-Rasul Hospital, Tehran, Iran were used. Antibiotic susceptibility testing was done after identification according to CLSI 2018. DNA extraction was done by boiling assay and oxa-23 and oxa-48 genes were detected by PCR. Thirty- two (63%) A. baumannii were confirmed according to microbiological and biochemical tests.  

      The highest resistance was observed against Piperacillin, Cefotaxime, Ciprofloxacin and Ceftazidime with 97% antibiotic resistance, and ampicillin/Sulbactam was the most effective antibiotic (78% sensitivity). Generally, 31 isolates of A. baumannii harbored the oxa-23 gene and none of them had oxa-48. The high prevalence of MDR A. baumannii in VAP is a great problem, especially for the nosocomial infection committee in hospitals.

     Rapid detection of MDR and carbapenemase producing strains can be the first step in preventing their spread in hospitals.

The present study aimed to evaluate the effects of various tissue inhibitors, including dentin powder, dentin matrix, bovine serum albumin, and bacterial lipopolysaccharide, on the antibacterial activity of sodium hypochlorite (NaOCl), chlorhexidine (CHX), and a new silver nanoparticle irrigant (Im-based AgNPs). In the first set of experiments, 950 µL of each irrigating solution was mixed with 50 µL of an Enterococcus faecalis suspension, and bacterial survival was assessed after 10, 30, and 60 seconds. In the second set of experiments, 100 µL of each inhibitor suspension was mixed with 100 µL of each irrigating solution and incubated for one hour. Afterwards, 100 µL of the bacterial suspension was added. Bacterial survival was assessed after 10 seconds and 10 and 60 minutes. Both sets of experiments were performed in triplicate. The colony-forming units were counted, and the log-transformed number was analyzed using the Kruskal-Wallis and Dunn tests. In the statistical analysis, P-value of less than 0.05 was considered significant. In the first set of the experiments, the antibacterial activity of NaOCl and CHX was significantly higher compared to the AgNPs and saline solutions at all the times (P˂0.05). In the second set of the experiments, the four inhibitors significantly inhibited the antibacterial effects of CHX and NaOCl (P˂0.05), with the exception of bacterial lipopolysaccharide, which had no effect on NaOCl. Similar to the negative control, AgNPs showed the high survival of the bacteria regardless of the presence or absence of the tissue inhibitors. According to the results, the tissue inhibitors affected the antibacterial activity of NaOCl and CHX at variables degrees. However, AgNPs showed no antibacterial activity regardless of the presence or absence of the inhibitors

Neisseria gonorrhea and Treponema pallidum as an obligate human pathogen are two common causes of sexually transmitted diseases (STDs). The present study aimed to determine the prevalence of N. gonorrhoeae and T. pallidum among human immunodeficiency virus (HIV) patients in the southwest Iran. This retrospective study was performed from 2004 to 2013, on HIV patients who were tested for detection of gonorrhea and syphilis infection at Shiraz HIV/AIDS Research Center. ELISA technique was used for preliminary detection of HIV and confirmed by a Western Blotting test. Gonorrhea was routinely diagnosed using direct Gram-staining and culturing on selective agar. Syphilis was routinely diagnosed by RPR test. Of the 806 HIV patients, 39 (2.6%) cases had co-infection with gonor rhea. Compared with mono-HIV infected patients, gonor rhea was significantly more likely among the males (69.4% vs. 92.3%, P=0.002). History of addiction and prison seems to be a significant risk factor for gonor rhea infection (P<0.05). Also, the mean of CD4+lymphocyte was higher among gonor rhea infected patients (368±238 vs. 415±328). Logistic regression analysis showed that sexual contact increased risk of gonococcal infection about 4 fold (OR: 4, CI: 1.7-9.39, P=0.001). None of the HIV patients had syphilis co-infection. As a preliminary survey, our findings provided unique information on the prevalence of gonorrhea and syphilis co-infections among HIV patients. Moreover, we introduced the main risk factors associated with gonorrhea co-infection in HIV patients in our region including gender, history of addiction and prison, CD4+lymphocyte count, and transmission routes for effective management of STDs.

 

Recently, nanotechnology has been demonstrated to be a promising application to overcome the problem of antibiotic resistance. In the present study, we aimed to determine the antibacterial activity of copper oxide nanoparticles (CuO NPs) on several multiple-drug resistant (MDR) uropathogenic strains.

This in vitro case-control study was performed on 4 uropathogenic bacteria including Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa. The antibacterial property was evaluated by well diffusion method at different concentrations of CuO NPs.

Overall, NPs concentration of 10, 25 and 50 µg/mL showed the remarkable antibacterial activity. A lower effect was seen against S. aureus strains. CuO NPs exhibited maximum bacterial growth inhibition against E. faecalis strains. In most of the cases, the zone of inhibition in 50 µg/mL concentration was closest to control positive antibiotics.

In summary, CuO NPs as an alternative to conventional antibiotics that are currently used showed dose-dependent on antibacterial activity against different uropathogens, specificity towards pathogenic Gram-positive bacteria. This promising antibacterial activity of CuO NPs suggesting the development of NPs coatings on the different surface of biomedical materials for applications in different antimicrobial control systems

Statement of the Problem: The rate of antibiotic resistance in bacteria and side effects of antibiotics and oral and teeth health care products are increasing. Therefore, researchers aim at finding new alternatives to control bacteria of dental caries.
The objective of this study was to investigate the inhibitory and bactericidal effects of different concentrations of zinc sulfate and zinc acetate solutions on the main recognized agent of dental caries, Streptococcus mutans.
In this experimental study, different concentrations of aqueous zinc sulfate and zinc acetate solutions were prepared and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these salts for Streptococcus mutans were determined in compare with penicillin, chlorhexidine by micro-serial dilution method. In addition, the diameters of zone of inhibition for these salt solutions in four concentrations along with chlorhexidine, as the control, were detected by the disc diffusion method.
MIC and MBC of zinc sulfate solution were higher than penicillin and chlorhexidine. There were not statistically significant differences between the MIC and MBC of zinc acetate solution, penicillin, and chlorhexidine. In 25 and 50 µg/mL concentrations, the diameters of inhibition zone for zinc sulfate were more than zinc ac
Zinc sulfate and zinc acetate salts with 37.19 and 31.25 µgr/mL concentration had inhibitory effect on Streptococcus mutans growth respectively, although, no priority in antibacterial activity of the studied zinc salts was determined in comparison with penicillin and chlorhexidine.

Statement of problem: Dental caries is a common infectious disease induced by Streptococcus mutans (S. mutans).
Due to the high incidence rate of dental caries and iron deficiency in the Iranian population, we have conducted this study to analyze the effects of iron acetate and iron sulfate on controlling the growth of S. mutans.
In this in vitro study, we evaluated the antibacterial effects of iron sulfate and iron acetate on S. mutans by the disk diffusion method, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results were compared to those for 0.2% chlorhexidine and penicillin as the controls.
Iron sulfate had higher MIC and MBC values compared to penicillin and chlorhexidine (P Iron sulfate and iron acetate solutions can inhibit the growth of S. mutans. Hence, different compounds that contain iron salts such as toothpastes, mouth washes, and food supplements can be produced to prevent dental caries and iron deficiency.

Statement of Problem: Indiscriminate use of antibacterial agents increases the antibiotic resistance, which consequently necessitates seeking alternatives such as herbal remedies.
The aim of this study was to evaluate the antimicrobial effect of hydroalcoholic extract of Helichrysum leucocephalum (H.leucocephalum) on Streptococcus mutans (S. mutans) growth as a major cause of dental caries.
In this study, hydroalcoholic extract of H. leucocephalum was prepared. The antibacterial effects, minimal inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) of hydroalcoholic extract of H. leucocephalum and penicillin were assessed. Agar well diffusion method and micro broth dilution assay were used on bacterial suspension adjusted to a 0.5 McFarland standard (equivalent to 1.5×108 CFU/mL).Each test was repeated four times to minimize lab errors.
In this study, the inhibitory zone of hydroalcoholic extract of H.leucocephalum in concentration of 100 mg/mL was 34±0.1 mm and for penicillin was 10 mm. The MIC and MBC of H.leucocephalum hydroalcoholic extract were 5.6±6.25, 21.6±6.25 mg/mL, respectively.
Hydroalcoholic extract of H. leucocephalum have antibacterial effect on S.mutans at a concentration of 12.5mg/mL, indicating possible application of this extract in prevention of dental caries; however, future researches are necessary.