Razi Journal of Medical Sciences

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ABSTRACT The purpose of this study was to investigate the extend of bacterial contaminatim of ice blocks being used on daily basis in the community. In this study fifty samples of ice blocks from April to September 1999 were collected from different areas in the city of Tehran. Experiments were carrid out for the determination of total count of bacteria and the identification of pathogenic organisms. The results indicated that from the total of 50 samples, 34(68%) were contaminated. The isolated pathogenic bacteria were 5 cases E.coli (10%), 21 cases pseudomonas aeroginosa (42%) and 5 cases staphylococcus aureus (10%). Other opportunistic bacteria present in the environment such as alkaligenes (%6), Acinetobacterspp (%4), Diphtheroidsspp (%46), Micrococcusspp (%16), Bascillusspp (%20) and coagulase negative staphylococcus(%40) were isolated from all the 50 samples. These results suggest that necessary precautions should be taken in production, transportation and distribution of the ice blocks to reduce the rate of bacterial contaminations.

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Corynebacterium urealyticum is a normal human skin flora. Mode of transmission is uncertain, but it can probably access to patients’ normally sterile sites endogenously. In spite of having low virulence, C. urealyticum has high resistance to antibiotics which allows survival in hospital setting. The incidence of infection caused by C. urealyticum is low. The most common infection is urinary tract infection, but infection in other sites has also been reported. In the present study out of 1338 positive samples, one case(0.074%) with corynebacterium urealyticum was isolated. The bacterium was sensitive only to vancomycine. Although C. urealyticum is not common, it is necessary to identify any diphtheroides micro-organisms from clinical site and to consider their clinical significance.

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    Background & Aim: Nalidixic acid is a quinolone antibiotic with excellent in vitro and in vivo activity against salmonella. It is often the first choice for treating drug resistance salmonella infections. Nalidixic acid resistance can often lead to resistance to fluoroquinolones such as ciprofloxacin. In this survey the extent of salmonella infections, the salmonella strains involved, antibiotic susceptibility patterns, and the MIC values towards nalidixic acid were investigated. Patients and Methods: During one year period(2005-2006), a total of 1333 diarrheal stool samples were collected from hospitalized patients. Stool cultures were performed on differential and selective media for salmonella isolation. A total of 45 salmonella spp.(species) were isolated(3.4%). Species identification were achieved by agglutination with species-specific antisera. Antibiotic susceptibilities were determined by disk-diffusion method(Kirby-Baure). The minimal inhibitory concentration(MIC) of drug-resistance salmonella isolates was performed by E.test. The study was a descriptive work. Data was analyzed by SPSS sftware. Based on difference ratio hypothesis there were no significant differences between the two methods. Results: A total of 45 salmonella spp.(3.4%) were isolated from 1333 stool samples. Agglutination tests with specific antisera indicated that 9 of them belonged to S. enteritids(20.0%), 6 S. typhimurium(13.3%), 4 S. montevideo(8.9%), 3 S. paratyphi C(6.7%), 2 S. paratyphi B(4.4%), 1 S. muenchen(2.2%), 1 S. derby(2.2%), 1 S. schwarzengrund(2.2%), 1 S. arizonea(2.2%) and 13(28.9%) untypable strains. All of the isolates were agglutinated with only anti O-antisera and non showed any reactions with anti-H antisera. Of the 13 untypable strains, 10(22.2%) belonged to the salmonella serogroup C and the remaining 3(6.7%) were serogroup B. Antibiogram tests indicated that 11(24.4%) of the salmonella isolates were resistant to Nalidixic acid in the disk diffusion agar method. However, determination of MIC values with E.test indicated that only 9(20.0%) of these strains showed MIC values within resistant range. Conclusion: The highest rate of nalidixic acid resistance was seen within the non-typhoidal salmonella strains. These strains are widely distributed within our environment and are the major etiological agents of human salmonellosis. Eleven strains were nalidixic acid resistant in the disk-diffusion method whereas, only 9 showed resistant trait with E.test. The MIC of the resistant isolates to nalidixic acid was ≥ 32µg//ml. Despite its high cost, it is therefore concluded that E.test gives a better and more accurate identification of drug-resistance trait as compared to disk diffusion agar method.

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Background & Aim:

clinical cases especially from hospitalized patients. Recently multiple drug resistant

isolated from clinical cases. Resistances were seen against drugs belonging to different antibiotic families. In this

survey, drug resistance in clinical isolates was studied with special reference to extended spectrum beta

lactamases.

Escherichia coli is one of the most important and prevalent bacteria isolated fromE.coli strains have been

Patients and Method:

for drug resistance by disc diffusion method. The minimal inhibitory concentration (MIC) of isolates resistant to

different antibiotics was determined by E-test. Beta lactamases production was tested with nitrocephin disc and

extended spectrum beta lactamases assays were performed with double disc synergy tests. Finally, Chi-square

and t-tests were used to analyze the data.

A total of 113 E. coli strains isolated from hospitalized patients were initially surveyed

Results:

these MDR strains were positive in nitrocephin test, indicating beta lactamases production. Double disc synergy

tests results showed production of extended spectrum beta lactamases in all MDR isolates.

From the total of 113 E.coli isolates tested, 47 (41.5%) showed multi drug resistant trait. All of

Conclusion:

Detection of 41.5% MDR trait, especially extended spectrum beta lactamases, in the clinical

E.coli

cephalosporins. It also necessitates conduction of a wider study to determine the extent of MDR

isolates points to the potential dangers posed by the widespread usage of extended spectrumE.coli

occurrence at national level.

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Background and Aim: Klebsiella pneumoniae (K. Pneumoniae) is one of the prevalent infectious bacteria, especially in hospitalized patients. Recently, its' multi drug resistance (MDR) trait has become more important and regarded as a virulant factor. In this study, we evaluated bla-ctx-m-type gene in clinical isolates of K.pneumoniae with multi drug resistance.

 Materials and Methods: In this descriptive cross-sectional study, a total of 280 K.pneumoniae strains were isolated from patients. Initially, we evaluated drug sensitivity with disk diffusion method. Then the minimum inhibitory concentration (MIC) of resistant isolates was determined with E-test stripes. The existence of ESBL (Extended Spectrum Beta-Lactamase) enzymes was identified by ESBL disks in Double Disk method. These resistances were evaluated with PCR. Finally, results were analyzed by SPSS software. Results: From total 280 K.pneumoniae, 62 samples (22.14%) showed multi drug resistance trait. 40 strains of these MDR isolates were completely resistant to the experimental cephalosporins, and positive in ESBL production by Double Disk methodology. These results were proved and evaluated with PCR and Sequencing.

  Conclusion: Detection of 22.14% MDR trait, especially extended spectrum beta-lactamases in resistant clinical K.pneumoniae isolates, points to the in usage of extended spectrum cephalosporins.

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    Background and Aim:�Staphylococcus aureus (S.aureus) is one of the most prevalent causes of nosocomial infections. It is also involved in community acquired infections. The resistance of this bacterium towards methicillin which has been reported since 1961, made Vancomycin the last choice for treatment of Staphylococcal infections.

Considering the reduced sensitivity or resistance to vancomycin which has been observed since 1996, this study was conducted with the aim of evaluating the vancomycin MIC values (Minimun Inhibitory Concentration) of S. aureus cells isolated from hospitalized patients and compared with those recovered from outpatients.

Materials and Methods: A cross sectional – analytic survey was conducted from 2006 till 2007. A total of 200 S.aureus strains were isolated from various clinical sources including blood, sputum,

urine and sinus secretions. Their susceptibilities to vancomycin were initially surveyed by disk diffusion method. Subsequently, the MIC values of each

individual strain towards vancomycin were determined by E-test strips, and the obtained data was analyzed by SPSS (V. 11) software. For statistical analysis, t-test was used.

Results: In 125 S. aureus strains isolated from hospitalized patients, the growth inhibition zones were 14-18 mm and the MIC values were 1-2mg/ml. In 75 S. aureus strains isolated from outpatients, the growth inhibition zones were 16-20 mm and the MIC values were 0.75-1.5 mg/ml.

Conclusion: The result of this survey shows increased MIC values for vancomycin in hospitalized patients as compared to outpatients.

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  Background: Group B Streptococci (GBS) or Streptococcus agalactiae is one of the most common causes of sepsis and meningitis in neonates and of invasive diseases in pregnant women. It can also cause infectious disease among adults with underlying medical conditions like immunocompromised individuals. Polysaccharide capsule is an important virulence factor. Nine GBS serotypes (Ia, Ib, II to VIII) based on capsular polysaccharide antigens have been described. Distribution of capsular serotypes varies over time and by geographic location. The aim of this study was to detect the capsular serotype distribution in GBS clinical isolates based on genotyping of cps-gene cluster and to determine the predominant serotypes of GBS.

  Methods: In this cross sectional study a total of 50 GBS strains were isolated from various clinical sources including: urine, vagina, semen and urethral secretions. GBS was identified by Gram stain, catalase test, CAMP test and also resistance to 0.04 U Bacitracin and SXT disks. DNA was extracted from all the isolates using the wizard SV Genomic DNA Purification system, Promega, USA. The capsular serotype of the isolates was assigned by using a specific-two Multiplex PCR assay. For statistical analysis, Chi-square method was used. SPSS V.13 was also used.

  Results: In the 50 GBS isolates, the predominant serotypes were III with 25 isolates (50%) and serotype V with 8 isolates (16%). Seven isolates (14%) belonged to serotype Ia and 7 isolates (14%) belonged to serotype II, respectively. Serotypes Ib, IV, VI, VII and VIII were not found and 3 strains were classified as nontypeable.

  Conclusion: Based on the results of this study, serotypes III and V were the predominant serotypes in GBS clinical isolates.