Iranian Journal of Microbiology
Volume:7 Issue: 6, Dec 2015

Coagulase negative Staphylococci (CoNS) are one of the most common bacteria found on human skin and on mucous membranes as a component of normal flora. The presence of CoNS in clinical specimens is frequently associated with an infectious aetiology or contamination. We aimed to evaluate CoNS species distribution and susceptibility patterns in specimens obtained from clinics and hospitals in the Northern area of Jordan. Standard identification methods showed the presence of CoNS in 223 specimens at different local hospitals. Susceptibility testing was performed using 18 antibiotics in accordance with the Clinical and Laboratory Standards Institute (CLSI) recommendations. Staphylococcus epidermidis and S. haemolyticus were found to be the most common species isolated from all spec- imens representing 122 (54.7%) and 52 (23.4%) of all CoNS species, respectively. Antibiotic susceptibility testing of CoNS species revealed their sensitivity to vancomycin, linozolid, rifampin and nitrofurantin, while showing a highly resistant pattern to ampicillin, penicillin, ceftriaxone, cefazolin, amoxicillin-clavulanic acid and erythromycin. Some variation of the susceptibility pattern of CoNS species were identified in specimens isolated from the ICU and paediatric hospital wards as well as from clinical specimens of urine, blood and catheter tips. The most common CoNS isolates were found to be S. epidermidis and S. haemolyticus with variable percentag- es according to the specimen source. Moreover, a high susceptibility CoNS to vancomycin, rifampin, and linezolid showed resistance to amoxicillin and penicillin.

Pseudomonas aeruginosa is a frequent opportunistic pathogen in health care associated infections that is highly resistant to the majority of β-lactams. The aims of this study were to access the antimicrobial susceptibility pattern of P. aeruginosa isolated from educational hospitals of Qazvin and Alborz provinces, to determine the prevalence of metallo-β-lactamase (MBL) among carbapenem non-susceptible isolates by combined disk (CD) method, and to detect the blaIMP, blaVIM, blaSIM, blaGIM, blaSPM and blaNDM-1-MBL genes. In this cross-sectional study, 300 P. aeruginosa isolates were collected from different clinical specimens in two provinces of Qazvin and Alborz hospitals, Iran. After identification of isolates by standard laboratory methods, antimicrobial susceptibility was done against 17 antibiotics according to clinical and laboratory standards institute (CLSI) guideline. CD method was carried out for detection of MBLs and the presence of blaIMP, blaVIM, blaSIM, blaGIM, blaNDM-1 and blaSPM-genes was further assessed by PCR and sequencing methods. In this study, 107 (35.66%) isolates were non-susceptible to imipenem and/or meropenem among those 56 (52.3%) isolates were metallo-β-lactamase producer. Twenty-four of 56 (42.85%) MBL-positive isolates were confirmed to be positive for MBL-encoding genes in which 14 (25%) and 10 (17.85%) isolates carried blaIMP-1 and blaVIM-1 genes either alone or in combination. Three (5.35%) isolates carried blaIMP and blaVIM genes, simultaneously. Considering the moderate prevalence and clinical importance of MBL-producing isolates, rapid identification and use of appropriate infection control (IC) measures are necessary to prevent further spread of infections by these resistant organisms.

Incidence of hospital-acquired diarrhea has increased rapidly and burn patients are at high risk of getting it. Infection with C. difficile is the most common cause of antibiotic associated diarrhea. The aim of this study was to determine the baseline characteristics and clinical presentation of hospital-acquired diarrhea and compare C. difficile and non-C. difficile diarrhea in burn patients treated at a burn center. During a 1-year study all patients with hospital-acquired diarrhea at Motahari Burn Hospital, Teh- ran, Iran enrolled in this study. We compared patients with a stool sample positive for C. difficile toxin or tracing the antigen in patients who were negative for detection of toxin in their stool sample specimens. Diarrhea developed in 37 patients out of 3200 admitted patients with a mean burn size of 34.8 ±20.1%. Among them, 8 patients had a positive result for C. difficile. The mean time between antibiotic therapy and occurrence of diarrhea was 9.5 ± 6.2 days. Nine (23.7%) patients died in the 7.8± 4.2 days, mostly due to co-morbidities. The mean duration of di- arrhea was 3.6 ± 2 days. Twenty two (57.9%) patients were treated with oral metronidazol and eleven (28.9%) patients were treated with combination of metronidazole and vancomycin, higher rate of combination therapy was seen in Clostridium difficile CDI. Overall, the prevalence of hospital-acquired diarrhea was 120/10,000 and 21% of them caused by infection with C. difficile. Presence of peripheral leukocytosis and colitis were the alarm sign for diagnosis of C. difficile infection.

Hydrocortisone is widely used in septic shock cases resistant to fluid and vasopressor therapy. It may result in increased blood pressure and survival. However the efficacy is no established among patients with severe burn and septic shock. Accordingly it was assessed in this study. The patients older than 14 years of age with resistant septic shock were enrolled during one-year period. The hydrocortisone was prescribed 100 mg three times per day and the alterations in systolic and diastolic blood pressures were recorded. Twenty-nine patients were enrolled including 19 men and 10 women. The mean age was 37 ± 19 years and the mean burn surface area was 60 ± 20. Fourteen patients had positive blood culture. The most common isolated microorganism were Pseudomonas aeuroginosa in 34.6%(10 cases), and then Acinetobacter in 13.8%(4 cases). The infection was from wound in 79% and the remaining 21% had pneumonia. Twenty-one patients had good response to hydrocortisone and the increase in systolic and diastolic blood pressures was significant; but the mortality rate was similar. Treatment with hydrocortisone would result in increase in systolic and diastolic blood pressure in burn patients with resistant septic shock.

Numerous procedures in biology and medicine require the counting of cells. Direct enumer- ation of Colony Forming Units (CFUs) is time-consuming and dreary accurate cell counting on plates with high numbers of CFUs is error prone. In this study we report a new indirect cell counting method that was developed based on the use of Redsafe fluorometric assay. The usefulness of Redsafe, a nucleic acid stain, in liquid medium is based on the binding of the fluorescent dye to DNA. Redsafe fluorometric assay was evaluated in comparison with MTT colorimetric assay as a colou- rimetric assay for enumeration of bacterial cells. Obtained results showed that fluorometric assay threshold for LB grown E. coli is 6×104 CFU/ml. Redsafe fluo- rescent assay can be used as a rapid and inexpensive method for bacterial enumeration and quantification with increased sensitivity. The sensitivity of the Redsafe fluorometric assay for detection and enumeration of bacterial cells was 2-log-unit more than that was observed for the MTT assay.

Mortality is highly variable within population of cultured fish due to virulent bacteria causing fish septicemia. The use of nano-silver marine fungal chitosan as antibiotic synergisers could be an alternative in the treatment of sepsis fish pathogens. Different bulk chitosan solutions were prepared from the mycelia of four marine fungi (Aspergillus terreus, Aspergillus flavipes, Tricoderma hamatum and Fennellia flavipes) and used as capping agents for silver nanoparticles. In vitro, the antibacterial activity of these preparations was determined against nine fish-sepsis causing bacteria, alone and in combination with nine antibiotics of choice used in aquaculture. Prepared fungal chitosans (CsF) were characterized by yield of chistosan obtained, degree of deacetylation and viscosity.Results and The maximum yield of chitosan (28%) was obtained from Aspergillus terreus. A. terreus chitosan (CsF), silver nanoparticles (AgNPs) and chitosan-silver nanoparticles (CsF-AgNPs) showed maximum activity at the minimum inhibitory concentrations average (MICAVG) 27.2, 18.2 and 7.9 μg/ml, respectively. Combination of CsF –AgNPs with amikacin (Ak) and rifampicin (RD) reduced the MIC values by 96 and 94%, respectively, with fractional inhibitory concentration index (FICI) = 0.42 and 0.50 as synergistic effect. It is promising to use CsF-AgNPs as enhancing agent in combination with antibiotics for fish sepsis therapy.

Pneumocystis jirovecii pneumonia (PJP) is a chronic fungal infection that caused by P. ji- rovecii. Disease is more prevalent among the HIV-infected patients. The colonization of pneumocystis in human respiratory system is associated with the airway inflammation and obstruction. The current study was conducted to identify the preva- lence of P. jirovecii among the patients with chronic pulmonary disorders in Ahvaz, Iran. In the present study, 115 bronchoalveolar lavage (BAL) specimens were collected from patients. Samples were subjected to Nested-PCR with specific primers. The second PCR products were used for sequencing analysis. Our findings demonstrated that 31(27.0%) of samples were positive for P. jirovecii. Nine patients (29%) have tuberculosis (TB) followed by, 1(3.2%) HIV positive and 21(67.7%) miscellaneous pulmonary disorders. Our results show that there was no significant differences between sex (male:female ratio, 17:14), TB, HIV and P. jirovecii in BAL samples (P>0.05). The current study is the first report from Ahvaz and it showed a relatively high frequency (27%) of P. jirovecii among patients with different pulmonary disorders. In addition Nested-PCR might be reliable technique for diagnosis of P. jirovecii, while the Grocott's methenamine silver (GMS) have a low sensitivity, which only two positive patients were identified.

Probiotic yeasts are used in production of functional foods and pharmaceutical products. They play an important role in promoting and maintaining human health. Until now, little work has been published on improving the survival of Saccharomyces in stimulated gastrointestinal condition. In this study the exposure of the yeast in the capsulate and free forms to artificial gastrointestinal conditions was assessed and the number of viable Saccharomyces cerevisiae cells during 0 to 120 mines in these conditions was evaluated by a pour plate method using sabouraud dextrose agar. Results showed the shape of the beads was generally spherical, sometimes elliptical with a mean diameter of about 50–90 µm. Also count of viable probiotic cells obtained for all the microcapsules were above the recommended levels for a probiotic food. Also decrease of approximately 4 logs was noted in the number of free cells after 2 h of incubation at pH2 and 8, when compared to decreases of about 2 logs in the all microencapsulated S. cerevisiae under similar conditions. It is concluded that microencapsulation process was significantly able to increase the survival rate of Saccha- romyces in a simulated gastrointestinal condition (p<0.05)