Background: To assess the prevalence of extended spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella strains in nosocomial and community-acquired infections. Methodology: The study was conducted at a centralized microbiology laboratory in the Eastern Province of Saudi Arabia. Laboratory records (January 2004-December 2005) were assessed. Associated resistance to a panel of antibiotics was determined. Results: A total of 6,750 Gram-negative organisms were assessed for ESBL-phenotype. ESBL was detected in 6% (409/6,750) of isolates, the majority of which were E. coli (83%). ESBL producers were significantly higher among isolates from in-patients 15.4% (143/927) versus outpatients (4.5%; 266/5,823); p < 0.05. Old age (older than 60 years) represented a significant risk for having an ESBL-producing pathogen. Urine was the major source of ESBL isolates in in-patients (46.1%) and outpatients (74.4%). The proportion of urinary E. coli isolates which were ESBL producers was significantly higher among in-patients (53/506; 10.4%) compared to outpatients (182/4,074; 4.4%); p < 0.05. Among in-patients, 60% of the ESBL associated infections were nosocomial. All were sensitive to imipenem but high levels of resistance to gentamicin, amikacin, amoxicillin-clavulanic acid and ciprofloxacin was shown. Conclusion: The findings document evidence of the spread of multiresistant ESBL-producers into the community. This has significant implications for patient management, and indicates the need for increased surveillance and molecular characterization of these isolates.

This paper reports a laboratory-based case study for the characterization of deposits from a crude cooler and reboilers in a Saudi Aramco refinery by microbiologically influenced corrosion (MIC) using microbial, metallurgic, and special analyses and correlates the Rietveld quantitative phase analysis of high-resolution X-ray powder diffraction (XRD) data of scale deposits with microbe compositions. Therefore, rapid in-field microbiological assays could be carried out to assess the potential of MIC. Based on the results, it can be highlighted that the MIC investigation showed that total bacteria and sulfate-reducing bacteria (SRB) were detected in all sampling locations. Methanogens, acid-producing bacteria, and sulfate-reducing archaea were not detected in all samples. Iron-oxidizing bacteria (IOB) were detected in the solid samples from reboilers C and D. Low loads of general bacteria and low levels of microbes with MIC potential were detected in both C and D samples. The trace amount of corrosion products in one sample and the low level of MIC microbes cannot justify the contribution of MIC microbes in the formation of accumulated solids in the system. The findings recommend conducting frequent sampling and analysis including water, oil, and solid from upstream locations to have more decisive evidence of the likelihood of the scale formation and possible contribution of MIC in the formation of deposits in the plant. Subsequently, quantitative phase analysis of XRD data of scale deposits by the Rietveld method revealed that the major phase is calcium sulfate in the form of anhydrate and the minor phases are calcium carbonate in the form of calcite and aragonite, silicon oxide in the form of quartz, and iron oxide corrosion product in the form of magnetite. The results are supported by high-resolution wavelength-dispersive X-ray fluorescence (WDXRF) results. These accurate and reproducible X-ray crystallography findings obtained from Rietveld quantitative phase analysis can guide the field engineers at the refineries and gas plants to overcome the problems of the affected equipment by drawing up the right procedures and taking preventive actions to stop the generation of these particular deposits.

In a setting of low MRSA prevalence, CP does not appear to be a useful predictor of nosocomial transmission or incidence.