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Bacterial persistence is recognized as a major cause of antibiotic therapy failure, causing biofilms, and chronic intractable infections. The emergence of persisters in Klebsiella pneumoniae isolates has become a worldwide public health concern. The goal of the present study is to investigate the formation of persister cells beside filaments in Iraqi K. pneumoniae isolates. A total of fifty clinical K. pneumoniae isolates were collected from different clinical specimens and identified using the genotypic identification by using specific primer (rpoB gene) from housekeeping genes. Persister cells investigation is performed by exposure of stationary phase K. pneumoniae isolates to a high concentration of ciprofloxacin (Ã--10 MIC) and counting the number of viable persister cells by CFU counts. Bacterial filament formation is detected and measured by light microscope scanning electron microscope. The results show the ability of these pathogenic bacteria to form persister cells to survive the bactericidal antibiotics and to cause chronic infection. Furthermore, persistent isolates have the ability to change in shape and size extensively, about 4 times increase in cell length than their normal length. These phenomena are possibly the initial stages of bacterial resistance prevalence. [ABSTRACT FROM AUTHOR]

Background: Multidrug-resistant bacteria (MDR) often contaminate hospital environment and cause serious illnesses. Quorum Sensing (QS) regulates a variety of downstream cellular processes, including antibiotics resistance mechanisms and biofilm formation, and causes harm to the host. This study investigates antibacterial susceptibility and biofilm formation of pathogenic bacteria in hospital environment. Methods: Hundred bacterial isolates were collected from various environments in the Medical City hospital. The antimicrobial susceptibility technique was evaluated through disk diffusion method. Next, biofilms formation was detected by the microliter plate assay. Finally, PCR was used to analyze the frequency of QS system genes. Results: Current findings showed that the predominant isolates were Acinetobacter baumannii (34%), Escherichia coli (30%), Pseudomonas aeruginosa (19%), and Klebsiella pneumonia (17%). In general, significant resistance was found related to trimethoprim (88%), Augmentin (88%), and cefotaxime (72%). Among all isolates, 62% of sensitivity was related to ciprofloxacin. Biofilm had been formed by 39% of isolates. PCR results showed that the frequency of lasI and rhlI gene was 70% and 61%, respectively. Conclusion: Current findings revealed that the hospital environment is a potential reservoir of MDR gram-negative pathogenic bacteria. Thus, we suggest that the health policymakers in Iraq must critically apply the guidelines and recommendations for monitoring the environments in the health sector. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is emerging as important hospital pathogenic bacteria, which can persist in the environment for extended periods of time. Sixty-three isolates belonging to the P. aeruginosa were isolated from different clinical sources. The antimicrobial susceptibility test was performed by the disk diffusion method, and the biofilm formation was assayed by the micro titer plate. Pyocyanin was extracted from the culture supernatants, and the absorbance values were measured using a spectrophotometer. The percentage of resistance shown by the isolates were 87.3 % for cefotaxime, 52.38 % carbenicillin, 39.68 % imipenem, 11.11 % colistin, and 7.93 % Piperacillin-tazobactam. About 9.09 % exhibited positive results for the phenotypic production of extended spectrum β-lactamase, whereas 40 % of the imipenem-resistant isolates were Metallo-β lactamase (MBLs) producers. Among the burn isolates, 22.22 % formed moderate biofilms and 6.35 % formed strong biofilms. 34.92 % of the burn isolates were pyocyanin producers. All the pyocyanin-producer isolates carried phenazine biosynthetic operon phzA-G gene. The results of this study revealed a high prevalence of pyocyanin production and biofilm formation in the P. aeruginosa isolates from burn infections. [ABSTRACT FROM AUTHOR]

Toxin Antitoxin (TA) systems have recently received much attention as one of the most promising antimicrobial targets. This study was designed to evaluate the presence of type II toxin antitoxin system and biofilm formation among imipenem resistant Klebsiella pneumoniae isolates in Baghdad. A total of 39(22.94%) Klebsiella pneumoniae isolates were collected from patients. Antimicrobial susceptibility test was performed and the biofilm formation was assayed by micro titer plate, then PCR was performed for detection of Toxin Antitoxin -Type II, Biofilm and Quorum sensing genes. The results show that the imipenem resistance was seen in 23(58.97%) of K.pneumoniae isolates. Then, the isolates showed levels of resistance percentage to antibiotic, with a highest resistance rate reached to (100%) for ampicillin and recorded lowest resistance rate to ciprofloxacin and levofloxacin reached to (10.26%) and (7.69%), respectively. Among these isolates, 22(56.41%) were biofilm producers. All 39 K.pneumoniae isolates showed different results for ompA and bap genes when were found by 9(23.08%) isolates for ompA, while, all isolates didn't have bap gene. Further, TA system genes were found by 15(38.46%), 15(38. 46%), three (7.69%) and five (12.82%) for mazEF, ccdAB, relBEand mqsR. On the contrary, all isolates didn't have QS system genes as lasIRandrhlIR genes. [ABSTRACT FROM AUTHOR]