Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients requires rapid and reliable characterization of isolates for control of MRSA spread in hospitals. This study evaluated polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) as a molecular typing technique for MRSA strains on the basis of protein A (spa) and coagulase (coa) gene polymorphisms to verify their ability in assessing the relatedness of isolates. Seventy-five MRSA isolates, from different ICUs of Alexandria University Main Hospital, were characterized using antibiotyping and PCR-RFLP analysis of coa and spa genes. Thirty-two antibiotypes were identified. coa gene PCR generated 3 types and 10 subtypes of band patterns. HaeIII restriction digestion of amplified coa gene products produced 5 major banding patterns and 12 subtypes. spa gene PCR products generated 4 major and 11 minor types, and their HaeII restriction digestion showed 5 major and 12 minor banding patterns. The combined coa and spa RFLP patterns generated 22 combined R types. Typing using coa PCR and PCR-RFLP had the same discriminatory index (DI) value (0.64), which was comparable to that of both spa PCR and PCR-RFLP techniques (0.68). The combined grouping increased the DI value to 0.836. The current study revealed that testing for multiple gene polymorphisms is more useful for local epidemiologic purposes.

Nosocomial spread of B. cepacia complex (Bcc) isolates amongst non-CF patients has been documented, where inadequate laboratory identification and limited treatment options are considered the main obstacles hindering accurate diagnosis and thus proper therapeutic outcome.The present study aimed to detect the isolation percentage of Bcc from patients in Alexandria Medical University Hospital (AMUH) according to site of infection (specimen), throughout a 6 month period. Out of 2079 specimens submitted to the microbiology laboratory, 35 strains were isolated on BCSA and biochemically identified as Bcc for the first time in this laboratory. The highest rate of isolation of Bcc isolates was from pus (85.7%) isolated from patients in the burn unit. Antibiotic susceptibility tests revealed that all Bcc isolated were Multi Drug Resistant (MDR), the highest susceptibility was to meropenem (88.5%) followed by ceftazidime (60%), tobramycin, chloramphenicol, piperacillin-tazobactam and tetracycline, while all strains were resistant to cotrimoxazole and ciprofloxacin.Minimal Inhibitory Concentration (MIC) determining tests showed that only 11.5% were resistant to meropenem at MIC > 16 lg/ml, while 40% of the strains were resistant to ceftazidime at MIC > 32 lg/ml. Those results for the time being indicate that meropenem is the best therapeutic option for Bcc infections in AMUH.

Background: P. aeruginosa exhibits several efflux pump systems that allow it to be resistant to several antimicrobial agents. Phenylalanine arginyl β-naphthylamide (PAβN) is an Efflux pump inhibitor (EPI) that can inhibit several multidrug efflux pumps. Objective: This study aimed to detect the efflux pump activity in FQ resistant P. aeruginosa, and to investigate the role of PAβN on FQ resistance. Methodology: P. aeruginosa isolates were subjected to antibiotic susceptibility testing by disc diffusion and those resistant to ciprofloxacin and levofloxacin were subjected to MIC detection before and after addition of PAβN. Also reverse transcription RT PCR was done for detection of mexA, mexC, mexE and mexX genes overexpression in the FQ resistant strains. Results: After the addition of PAβN, 95.9% and 94.5% of the isolates showed reduction in MICs of ciprofloxacin and levofloxacin respectively, 8.20% and 27.4% of the isolates restored susceptibility to those drugs respectively and 8.20% reverted to levofloxacin intermediate breakpoint. MexE was the most common efflux pump overexpressed, followed by mexX and mexA. When using EPI 96.8% and 95.3% of the isolates showed both overexpression and reduction of ciprofloxacin and levofloxacin MIC respectively. Using a cut- off point of ≥4 fold reduction in levofloxacin MIC discriminates efflux pump overexpressing from non-overexpressing isolates, (sensitivity of 70%, specificity of 67%). Conclusion: Efflux pump mediated resistance is an important mechanism contributing to multidrug resistance in P.aeruginosa as proven phenotypically and genotypically, with mexE being the most commonly expressed. The addition of PAβN to levofloxacin could be used as a phenotypic test for detection of efflux pump overexpressing isolates and may be effective to restore the levofloxacin susceptibility.

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