Distribution of Class D Carbapenemase and Extended-Spectrum ß-Lactamase Genes among Acinetobacter Baumannii Isolated from Burn Wound and Ventilator Associated Pneumonia Infections.

INTRODUCTION: Resistance to Acinetobacter baumannii is dramatically on the rise in Iran. Therefore, it is important to study resistance pattern among Acinetobacter isolates which is a common cause of nosocomial infections. AIM: To investigate antibiotic resistance patterns and the role of resistant genes and biofilm formation in the induction of resistance among Acinetobacter baumannii isolated from burn wound and ventilator associated pneumonia infections. MATERIALS AND METHODS: Total 103 isolates such as 33 burn samples from Rasool Akram Hospital and 70 isolates from ventilated patients in Shahid Motahhari Hospital were identified with A. baumannii using biochemical method, and then identified to species level with PCR of gyrB and blaOXA-51 gene. Antibiotic sensitivity pattern for ß-lactam and carbapenem antibiotics was assessed using Agar disc diffusion test and E-test. The presence of different carbapenemase and metalo-ß-lactamase (blaOXA-51-like, gyrB, blaOXA-23-like, blaOXA-24-like, blaOXA-58, blaVEB, blaPER, blaGIM, blaSIM, blaIMP, blaVIM), extended-spectrum ß-lactamases (blaTEM, blaSHV) and two insertion sequences genes (ISaba1, IS1113) was assessed. Biofilm formation of all isolates was then assessed. Chi-square analysis or Fisher's-exact tests were used for statistical analysis. A p-value <0.05 was considered statistically significant. RESULTS: Colistin was the most effective antimicrobial agents, although 10.7% (11/103) of the isolates were resistant. The high rate of resistance to meropenem (93.2%) and imipenem (90.3%) was determined. Also, with exception of ampicillin-sulbactam, surprisingly the resistant rate was 28.2%, the resistance to ß-lactam antibiotic was dramatically increased. Co-existence of two and three blaOXA genes was also determined. The blaOXA-58 was detected in only one isolate. The blaTEM and blaOXA-23 was the most prevalent Extended-Spectrum ß-Lactamases (ESBL) gene. All isolates were biofilm producers. CONCLUSION: Antibiotic resistance is increasing among A. baumannii isolates which is due to excessive use of antibiotics and also acquired resistant genes and biofilm production. Resistance to nearly all antimicrobial agents especially colistin as end choice for treatment of multiple drug resistance A. baumannii is a big concern.

Synergistic Effect of Colistin and Rifampin Against Multidrug Resistant Acinetobacter baumannii: A Systematic Review and Meta-Analysis.

The existence of infections caused by multidrug resistant (MDR) Acinetobacter baumannii is a growing problem because of the difficulty to treat them. We examined the published literature and focused our analysis on the investigation of the synergism of colistin and rifampin against MDR A. baumannii isolates via systematic review and meta-analysis. A systematic literature search was performed using the following 4 databases (PubMed, Scopus, EMBASE and ISI Web of Sciences). The related articles were evaluated during the period from December 2014 to January 2015. Information based on resistance and sensitivity to antibiotics, the minimum inhibitory concentration and the effects of two antibiotics on each other including synergism, antagonism, relative synergism and additive antagonism were extracted. A meta-analysis of 17 studies including 448 samples was brought into process and 2% (95% CI 0-4%) and 72% (95% CI 56-89%) resistance to colistin and rifampin were observed, respectively. 42% of all isolates showed MIC = 4 µg/ml (95% CI 14-69%) to rifampin and 30% MIC= 2 µg/ml to colistin (95% CI 3.8-78%). MIC50 and MIC90 for both rifampin and colistin were 2 µg/ml and 4 µg/ml, respectively. 63% of the strains demonstrated synergy (95% CI 37-90%), 7% were highlighted as relative synergism (95% CI 0.0- 13%), 3% showed an additive effect (95% CI -0.0-7%) and 14% were indifferent (95% CI 6-23%). The antagonistic effect was not observed in this combination. Synergy rates of time-kill assay in rifampin and colistin combinations were generally higher than those of check bored microdilution and E-test method. The results demonstrated that the combination therapy could be more useful when compared to monotherapy and that this strategy might reduce the resistance rate to rifampin in MDR A. baumannii isolates.

Risk factors for Candida parapsilosis bloodstream infection in a neonatal intensive care unit: a case-control study.

BACKGROUND: Candida parapsilosis is increasingly responsible for invasive candidiasis in neonates. This study investigates phenotypic and genotypic features of C. parapsilosis microbial isolates and underlying clinical conditions associated with acquisition of C. parapsilosis in a neonatal intensive care unit (NICU) in Italy. METHODS: Identification of C. parapsilosis was performed by VITEK® 2 and MALDI TOF and confirmed by analysis of internal transcribed spacer ribosomal DNA sequences. Genotyping was performed by PCR fingerprinting. Antifungal susceptibility of strains was evaluated by microdilution. A case-control study was designed to identify risk factors for C. parapsilosis bloodstream infection. RESULTS: During the study period (April 2009- April 2012), C. parapsilosis was responsible for 6 umbilical catheter and 11 central catheter-associated bloodstream infection in 17 neonates in the NICU. Molecular typing identified identical fingerprinting profile in all C. parapsilosis isolates from neonates. Fifteen of 17 C. parapsilosis isolates were susceptible to all antifungal drugs, two isolates were resistant to fluconazole and intermediate susceptible to itraconazole. Low birthweight, gestational age and time to exposure to assisted ventilation were risk factors for C. parapsilosis infection in neonates in the NICU at univariate and multivariate analysis. CONCLUSION: C. parapsilosis bloodstream infections in the NICU were caused by a single epidemic clone. Low birthweight, gestational age and time to exposure to invasive devices, with predominance of assisted ventilation, were the clinical conditions associated with C. parapsilosis bloodstream infection in the NICU.

3rd Generation of Cephalosporins and Monobactam Resistant Among Pathogenic Bacteria Collected from Ilam Hospitals During 2008 to 2015: A Systematic Review and Meta-Analysis.

BACKGROUND: Recently, increasing antibiotic resistance is causing serious publichealth concerns worldwide. This phenomenon increased patient's morbidity and mortality rate, particularly in immunocompromised individuals. METHODS: Considering that antimicrobial resistance can vary according to geographical location, we investigated the status of antibiotic resistance in Ilam province from 2008 to 2013. RESULTS: The results of our study showed that antibiotic resistance rates to aztreonam, cefotaxime, ceftazidime and ceftriaxone were 38%, 39%, 43% and 48% respectively. CONCLUSION: Antibiotic resistance had increased (except for aztreonam) during the period from 2008 to 2013.

Prevalence of cagA and vacA among Helicobacter pylori-infected patients in Iran: a systematic review and meta-analysis.

The varieties of infections caused by Helicobacter pylori may be due to differences in bacterial genotypes and virulence factors as well as environmental and host-related factors. This study aimed to investigate the prevalence of cagA and vacA genes among H. pylori-infected patients in Iran and analyze their relevance to the disease status between two clinical groups via a meta-analysis method. Different databases including PubMed, ISI, Scopus, SID, Magiran, Science Direct, and Medlib were investigated, and 23 relevant articles from the period between 2001 and 2012 were finally analyzed. The relevant data obtained from these papers were analyzed by a random-effects model. Data were analyzed using R software and STATA. The prevalence of cagA and vacA genes among H. pylori-infected patients was 70% (95% CI, 64-75) and 41% (95% CI, 24.3-57.7), respectively. The prevalence of duodenal ulcers, peptic ulcers, and gastritis among cagA+ individuals was 53% (95% CI, 20-86), 65% (95% CI, 34-97), and 71% (95% CI, 59-84), respectively. Odds ratio (OR) between cagA-positive compared with cagA-negative patients showed a 1.89 (95% CI, 1.38-2.57) risk of ulcers. In conclusion, the frequency of cagA gene among H. pylori strains is elevated in Iran and it seems to be more frequently associated with gastritis. Therefore, any information about cagA and vacA prevalence among different H. pylori-infected clinical groups in the country can help public health authorities to plan preventive policies to reduce the prevalence of diseases associated with H. pylori infection.

Surveillance of healthcare-associated infections in a neonatal intensive care unit in Italy during 2006-2010.

BACKGROUND: Healthcare-associated infections (HAIs) are a frequent complication associated with hospitalization of infants in neonatal intensive care units (NICUs). The aim of this study was to evaluate and describe the results of surveillance of HAIs in a III level NICU in Naples, Italy during 2006-2010. METHODS: The surveillance covered 1,699 neonates of all birth weight (BW) classes with >2 days NICU stay. Infections were defined using standard Centers for Disease Control and Prevention definitions adapted to neonatal pathology and were considered to be healthcare-associated if they developed >2 days after NICU admission. RESULTS: One hundred-fifty-three HAIs were diagnosed with a frequency of 9% and an incidence density of 3.5 per 1000 days of hospital stay. HAIs developed in all BW classes, but patients weighing≤1000 g at birth were more affected with a decreasing trend from the lowest to the highest BW classes. Sepsis proved to be the most frequent infection (44.4%), followed by urinary tract infection (UTI) (28.8%), pneumonia (25.5%) and meningitis (1.3%). Device associated infections (i.e. central line-associated bloodstream infections (BSIs), umbilical catheter-associated BSI and ventilator associated pneumonias (VAPs) represented 64.1% of all HAIs. Most frequent pathogens responsible for all types of infections were: P. aeruginosa (17%), C. parapsilosis (16.3%), E. coli (13.1%), C. albicans (10.5%), non- extended spectrum beta-lactamase (ESBL) K. pneumoniae (7.8%), and coagulase-negative Staphylococci (5.2%). No microbiological diagnosis was achieved for 6.5% of infections. CONCLUSIONS: HAIs developed in all BW classes but low BW neonates were at major risk to acquire HAIs in our NICU. Use of central line-, umbilical-catheter and mechanical ventilation was associated with higher risk of infection. Our findings highlight the importance of an extensive surveillance approach in the NICU setting, which includes all BW classes of neonates and monitors infections associated with the use of medical devices.