Organic solvent-tolerant bacteria are a novel and unique group of extremophilic microorganisms that can thrive in many harsh conditions. These bacteria are being explored for their potential in industrial applications, since their biocatalysis contents might be active in the presence of very high concentrations of organic solvents. In the present work, a screening programme was designed to isolate a novel methanol-tolerant bacterium. Among several different isolated bacteria, strain IE-93 was chosen as a best producer of lipase in the presence of 5% methanol. Phylogenetic characterization using 16S rDNA nucleotide sequence confirmed that the strain can be placed in STENOTROPHOMONAS genus and tentatively named STENOTROPHOMONAS sp. strain IE-93. The secreted lipase was purified by combination of amicon concentration, Q-Sepharose and Sephacryl S-200 column chromatography. The purified enzyme showed homogeneity on SDS-PAGE with apparent molecular mass of 60 kDa. The optimum pH and temperature for the enzyme were 8.0 and 35 oC respectively. The hydrolytic activity on various substrates (C4, C8, and C18 acyl chain) revealed that the purified enzyme has the highest priority for long acyl chains. Survey on lipolytic activity of the enzyme in the presence of various concentration of methanol (from 10% to 50%) showed its reasonable stability and more than 77% of initial activity was retained after 1 h incubation in 40% methanol. In overall, long alkyl chain substrate specificity and convenience stability in the presence of methanol suggest that the isolated lipase has biotechnological applications especially in low water content reactions and biodiesel production.

Background: STENOTROPHOMONAS maltophilia and Acinetobacter baumannii are serious offending agents of nosocomial pneumonia and of serious morbidity and mortality in intensive care units (ICU). We report an unexpected sudden surge in cases of pneumonias caused by the above organisms in an intensive care unit of a community hospital in a span of two months. The source was traced back to a contaminated bronchoscope.Materials and Methods: The records from the patients with diagnosis of pneumonia with the above organisms were retrospectively reviewed. Specimens from the ports and channels of the bronchoscope that was suspected to be the cause were taken and microbiologically analyzed.Results: Two patients with Acinetobacter and four patients with STENOTROPHOMONAS positive bronchoalveolar lavage (BAL) fluid cultures were identified within a 2-month period in one of our two intensive care units. All of the patients were mechanically ventilated, and had clinical features of pneumonia. Their bronchoscopies were performed and their BALs were obtained by a scope with an identical serial number. The microbiologic evaluation of samples taken from the suspected scope revealed that it was improperly decontaminated between procedures. After implementation of strict and revised decontamination protocol, there were no further cases of pneumonia caused by the above organisms in a span of several months in mechanically ventilated patients.Conclusion: Inadequate disinfection of bronchoscopes and cross contamination between patients could be a potential cause of ventilator-associated pneumonia. Strict implementation of infection prevention guidelines in bronchoscopies of mechanically ventilated patients could prevent cases of ventilator-associated pneumonias by nosocomial agents including S. maltophilia and A. baumannii.

Background: STENOTROPHOMONAS maltophilia (S. maltophilia) is a multiple-antibioticresistant opportunistic pathogen that is being isolated with increasing frequency from patients with health-care-associated infections. S. maltophilia is inherently resistant to most of the available antimicrobial agents. Spread of resistant strains has been attributed, in part, to class I integrons. In vitro susceptibility studies have shown trimethoprim- sulfamethoxazole and new floroquinolones as two important agents with activity against these organisms.Methods: 150 isolates of S. maltophilia were isolated from clinical samples such as respiratory discharges, sputum, and catheter and hospital environments. These isolates were also subjected to susceptibility testing and polymerase chain reaction for four groups of genes including int encoding integron elements, sulI and sulII encoding trimethoprim- sulfamethoxazole resistance and smqnr encoding quinolone resistance.Results: The rate of resistance to trimethoprim-sulfamethoxazole was up to 27 (18%) and the highest resistance to quinolone family belonged to ofloxacin (20%) and the lowest rate was for gatifloxacin (16%). The results showed that 14% of isolates contained integron elements concomitantly with sulI and sulII genes.Conclusion: Resistance rate of S. maltophilia to co-trimoxazole and fluoroquinolones and detection of integron elements between isolates in this study showed that this rate corresponded to other data obtained from other studies.

Background: Due to the difficulty of treatment caused by its numerous mechanisms of resistance, only four kinds of antibiotics are recommended for the therapy of STENOTROPHOMONAS maltophilia infections associated with significant morbidity and mortality. Objectives: In this four-year study, we aimed to determine the evolution of drug resistance to S. maltophilia base on drug classification guidelines recommended by the Institute of Clinical and Laboratory Standards. Methods: A total of 1876 strains of S. maltophilia was separated from multifarious clinical specimens among January 2016 and December 2019. VITEK 2 Compact microbial system was used for speciation level identification and antibiotic sensitivity test. Results: A total of 1876 strains of S. maltophilia strains were separated from sputum specimen type (70. 63%), Followed by bronchial (6. 18%), blood (4. 16%), and bronchoalveolar lavage samples (4. 32%). Moreover, 695 strains of S. maltophilia strains were separated from intensive care unit (ICU) department (37. 05%), andthen neurosurgeryward(10. 66%), integrative Chineseandwestern medicine ward (7. 25%), general surgery ward (6. 66%). The results of minocycline antibiotic of S. maltophilia with a drug resistance rate of 0. 3%. From 2016 to 2019, the resistance rate of cefoperazone/sulbactam decreased from 20. 8% to 15. 2%, the resistance rate of trimethoprimsulfametoxasole decreased from 7. 9% to 4. 5%. The resistance rate of minocycline fluctuate in 0. 0%% between 0. 7%. However, the resistance rate of levofloxacin increased from 7. 7% to 8. 0%. Conclusions: In this study, S. maltophilia was detected in a variety of specimen types of different clinical departments, with the most detected in ICU patients and sputum specimen. S. maltophilia was sensitive to minocycline and levofloxacin, but the situation of cefoperazone/sulbactam resistance was not optimistic. The results of this study indicate that minocycline is considered to be the most effective antibiotic for the treatment of S. maltophilia. Therefore, we still need to strengthen the drug resistance monitoring, timely acquisition of S. maltophilia drug resistance changes, and actively take effective measures to deal with the drug resistance of S. maltophilia.

Background: STENOTROPHOMONAS maltophilia is an opportunistic bacterium, contributing to different hospital-acquired infections and can be acquired from different hospital setting sources. Epidemiological study of S. maltophilia in the hospital also demonstrates the intrahospital distribution of certain strains of bacteria in healthcare facilities. The aim of the current study was to identify the molecular epidemiology of S. maltophilia isolates from clinical and environmental sources within a hospital. Methods: A total of 400 samples (clinical and environmental) were collected from the different settings of hospital. Following the standard biochemical testing and 23S rRNA genotyping, the molecular typing of S. maltophilia isolates was determined using the MLST technique. Also, the frequencies of zot and entF virulence genes among S. maltophilia isolates were examined by PCR technique. Results: Based on the biochemical testes and PCR targeting 23S rRNA gene, 22 S. maltophilia isolates were identified. The MLST analysis demonstrated that these isolates were assigned to 14 ST, and 6 out of 14 STs were common among clinical and environmental samples. All 22 isolates were identified in the PubMLST database. The PCR screening demonstrated that none of 22 S. maltophilia isolates had zot virulence gene, while the entF gene with the 59% frequency was observed in 13 out of 22 isolates. Among these 13 isolates, 6 STs were common in clinical and environmental isolates. Conclusion: Our study showed the clonal relatedness between clinical and environmental sources of the S. maltophilia isolates in a hospital. Further studies are required to understand the epidemic situation of this pathogen in the clinic and the environment.