ABSTRACT
OBJECTIVES: Multidrug resistance (MDR) and emergence of extended-spectrum ß-lactamases (ESBLs) among uropathogenic Escherichia coli have been reported worldwide, but there was no information on the detection of blaCTX-M-15 in major teaching hospitals in Libya. The aim of the study was to investigate the occurrence of CTX-M-15 ß-lactamases producers isolated from five teaching hospitals in Tripoli, Libya. METHODS: A total of 346 urine samples were collected from hospitalized patients in five teaching hospitals with a diagnosis of urinary tract infection (UTI). Phenotypic confirmation of ESBLs was confirmed by E-test strip; all ESBL-producing E. coli isolates were screened for the blaCTX-M-15 gene. RESULTS: The distribution of ESBL-producing E. coli varied among the five hospitals. The highest proportion was identified in Tripoli Medical Centre (67.6%). There were extremely high proportions of isolates resistant to ceftriaxone, cefepime, and ceftazidime (93.0-100.0%) among ESBL producers compared to non-ESBL producers (2.2-4.7%). MDR was detected in 22.2% of isolates. The majority of isolates (85.9%) in which blaCTX-M-15 was identified were ESBL producers. There was a correlation (p < 0.001) between expression of CTX-M-15 and resistance to ceftazidime. CONCLUSIONS: The isolation of MDR ESBL-producing uropathogens expressing the CTX-M-15 gene will limit the choices clinicians have to treat their patients with UTIs. Continued surveillance and implementation of efficient infection control measures are required.
ABSTRACT
INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin poses a threat for patients in burn units throughout the world. This study aimed to investigate the reduced susceptibility to vancomycin of MRSA isolated from wounds of patients admitted to the Burns and Plastic Surgery Centre in Tripoli, Libya. METHODOLOGY: All isolates were initially identified by chromagen medium then confirmed by PCR. The minimum inhibition concentration (MIC) was determined by E-test glycopeptide resistance detection (GRD). RESULTS: During the study, 210 isolates were obtained from 560 patients representing 132 (62.9%) and 78 (37.1%) of total samples received during years 2009 and 2010, respectively. MIC levels for vancomycin ranged from 0.5 to 2 µg/ml during the study, 13% of isolates displayed MIC of 1.5 µg/ml and 9% of the isolates displayed 2 µg/ml. Although MRSA isolates decreased dramatically during 2010 (37.1%) compared to 2009 (62.9%), overall, there was a significant increase in the proportion of MRSA isolates exhibiting higher vancomycin MICs during 2010 compared to 2009 (P = 0.0155). There was a significant increase of MICs at 1 µg/ml during 2010 compared with 2009 (P = 0.36). No vancomycin intermediate or resistant strains were found. CONCLUSION: There was a significant increase in the proportion of MRSA isolates exhibiting higher vancomycin MICs. We recommend that MRSA isolates should be monitored. Furthermore, implementation of infection control measures is urgently needed to prevent the spread of MRSA.
