Background: Ventilator-associated pneumonia (VAP) is a common nosocomial infection among hospitalized patients who have undergone intubation and mechanical ventilation for more than 48 hours. Patients admitted to the intensive care unit (ICU) are at risk of developing life-threatening VAP due to specific conditions, especially with Gram-negative pathogens with advanced drug resistance. Hereby, the control of these agents and its monitoring is of particular importance. In this study, the pattern of antibiotic resistance of Gram-negative bacteria isolated from tracheal culture of patients with VAP investigated in ICU of Imam Khomeini Hospital of Ahwaz. Materials and Methods: In this cross-sectional study, tracheal samples were collected during April 2016 to April 2017 from patients who were on mechanical ventilation in ICU of Imam Khomeini Hospital in Ahwaz, Khuzestan province, southwest of Iran. After isolation, bacterial strains were identified using biochemical tests. Then, antimicrobial resistance pattern of these isolates investigated using standard disc diffusion according to clinical and laboratory standards institute 2016 (CLSI 2016) guidelines. Results: A total of 111 bacterial isolates were identified which were as following; Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, STENOTROPHOMONAS maltophilia, and Serratia marcescens, with prevalence of 54%, 19. 8%, 14. 4%, 6. 4%, 4. 5%, and 0. 9%, respectively. Antibiotic susceptibility test of isolates showed that almost all isolates had high resistance to treatment antibiotics and were multi-drug resistance (MDR). The A. baumannii isolates were resistant to ciprofloxacin and piperacillin-tazobactam, but ampicillin-tazobactam had a good effect. Conclusion: The results of this study showed that patients admitted to ICU due to their conditions of treatment are more likely to develop VAP by Gram-negative pathogens. The empirical treatment of VAP due to predominant bacterial causes and emerging drug resistance has become more challenging. It requires to use of multidrug regimens for routine clinical practice. It should be noted that in order to appropriate antimicrobial therapy, precise and correct diagnosis is very important.

Backgraound: Venous and arterial catheters are used ordinary for continuous hemodynamic evaluation in cardiac surgery intensive care units. The catheters are one of the most important risk factors for nosocomial infection and mortality of hospitalized patients. The aim of this study was to evaluate the rate of bacterial colonization of intravascular catheters and catheter related bloodstream infection in Shahid Madani intensive care unit.Methods: 150 admitted patients that had intravascular catheter for more than 48 hours were enrolled in this study during one year period. The tip segment of catheters and insertion site cultures were assessed.Results: The rate of colonization was 13 (8.7%). The isolated bacteria were Escherichia coli (23.1%), Pseudomonas aeroginosa (23.1%) staphylococcus aureus (7.7%), coagulase negative staphylococcus (7.7%), Proteus vulgaris (7.7%), STENOTROPHOMONAS maltophilia (7.7%), Candida albikans (7.7%), nonfermentative gram negative bacilli (7.7%) and Acinetobacter spp (7.7%).Conclusion: The rate of catheter colonization was acceptable in comparison to the other studies. The most common isolated bacteria were Escherichia coli and Pseudomonas aeroginosa. In this study, the important risk factors were duration of catheter use, duration of hospitalization and positive blood culture.

Background: Non-fermenting Gram-negative bacteria are unable to ferment sugars in order to generate energy. They are ubiquitous in nature, and have a wide geographic distribution.They are also common in hospital settings, and may be isolated from humidifiers, ventilator machines, dialysis machines and other equipment, as well as from the skin of hospital personnel.Objectives: This study focused on the isolation of multidrug resistant (MDR) non-fermenting Gram negative bacteria from clinical samples. Antimicrobial susceptibility, detection of extended spectrumβ-lactamases (ESBL), and the presence of CTX-M and Metallo b-lactamase (MBL) in the isolated bacteria were evaluated.Materials and Methods: Agar dilution method was used to test the susceptibility of the isolates to 10 antibacterial agents. All the isolates that were resistant to ³ 3 antibacterial agents from different classes were regarded as MDR (111 isolates) and were selected for further studies.β-lactamase and ESBL production were detected by nitrocefin discs, combined discs (CD) and double discs plus CD (DCDT).bla CTX-M and MBL were detected by PCR and EDTA synergy methods respectively.Result: Among the MDR isolates the isolation frequency of Pseudomonas aeruoginosa, STENOTROPHOMONAS maltophiliaand Acinetoacter baumannii were 83.7%, 9.9% and 6.3% respectively.Resistance to imipenem (0.9%) and Ceftazidim (13.6%) was low, but resistance to otherβ-lactams was high, and 29.7% were resistant to ³ 6 antibacterial agents from different classes simultaneously.β-lactamase was produced by 41.4% of the MDR isolates. Detection of ESBLs by a CD (59.4%) or DCDT test (46.8%) was not significantly different, but with a combination of CD and DCDT a higher percentage of ESBLs in the isolates (P£0.00) could be detected. The blaCTX-M and MBL phenotype were detected in two different strains of P. aeruoginosa.Conclusions: The presence of a high percentage of isolates producing ESBLs which are resistant to different antibacterial agents may result in treatment failure in infected patients.Careful detection of antimicrobial resistant strains is needed in order to avoid underestimation or misidentification of ESBLs. An effective hospital infection control policy is also necessary in order to prevent further resistance to antimicrobials in the region.