Abiola C. Senok

Prevalence and Antimicrobial Susceptibility Pattern of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in the United Arab Emirates

Objective: To investigate the prevalence and antibiotic susceptibility pattern of extended-spectrum β-lactamases (ESBL)-producing Enterobacteriaecae among patients in the United Arab Emirates. Materials and Methods: A total of 130 Enterobacteriaceaecomprising of Escherichia coli (n = 83), Klebsiella pneumoniae (n = 45) and Klebsiella oxytoca (n = 2) was studied. Of these 130 isolates, 64 were from urine. ESBL screening was by disc diffusion and confirmatory tests for ESBL phenotype were conducted using BD Phoenix™ ESBL System and cephalosporin/clavulanate combination discs. Susceptibility to a panel of antibiotics was evaluated. Results: Of the 130 isolates, 53 (41%) were identified as having ESBL phenotype; of these, 32 (60%) were E. coli, 20 (36%) K. pneumoniae and 2 (4%) K. oxytoca. ESBL phenotype was seen in 100% of endotracheal tubes isolates, 20 (31%) from urine, 7 (58%) from blood and 4 (80%) from catheter tips. Amikacin susceptibility was 100%. Over 90% of ESBL isolates showed resistance to aztreonam and cephalosporins. All Klebsiella isolates were carbapenem sensitive. One ESBL isolate showed intermediate resistance to imipenem and meropenem (both MIC 8 µg/ml), cefotetan (MIC 32 µg/ml) and piperacillin/tazobactam (MIC 32 µg/ml). MIC for the carbapenems was lower in non-ESBL isolates (0.034 µg/ml) than ESBL isolates (0.071 µg/ml). Resistance to gentamicin, ciprofloxacin and piperacillin/tazobactam was higher in ESBL than non-ESBL isolates (p < 0.05). Conclusion: A high prevalence of ESBL-producing bacteria exists among in-patients in the United Arab Emirates. Amikacin and carbapenems remain the most effective drugs, but the presence of carbapenem-resistant ESBL-producing E. coli and occurrence of multidrug resistance are of concern. Continued surveillance and judicious antibiotic usage are recommended.

Prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae in Bahrain.

OBJECTIVES To determine the occurrence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in Bahrain. METHODS Retrospective analysis of records (January 2005-December 2006) at the Microbiology Laboratory of the Salmaniya Medical Complex, Bahrain which is the major national diagnostic laboratory. RESULTS Out of a total of 11,886 member of family of Enterobacteriaceae isolated, 2695 (22.6%) were ESBL producers. Majority of ESBL isolates were from inpatients (n=2363; 87.7%). Escherichia coli (52.2%) and Klebsiella pneumoniae (24.3%) were predominant and distributed comparatively in the hospital wards while Proteus spp. (17.6%) was predominant in medical wards. Urine was the major source (52.2%) with low occurrence in blood cultures. No carbapenem resistant isolates was identified but resistance to three classes of antibiotics was exhibited by >25% of the isolated ESBL strains. Nitrofurantoin resistance was identified in 38.2% of urinary isolates. CONCLUSION This is the first report from Bahrain and it indicates that the prevalence of ESBL-producing isolates is high. Carbapenems were the most active drug against the ESBL-producing isolates. We recommend strict infection control to prevent trafficking into the community.

Vaginal lactobacilli, probiotics, and IVF

Perturbation of the normal lactobacilli-dominated vaginal microflora is associated with reproductive failure and adverse pregnancy outcomes, ranging from early pregnancy loss to late miscarriage and preterm birth. As high rates of bacterial vaginosis are observed with IVF patients, abnormal vaginal microflora presumably explain, at least to some extent, reproductive failure as well as the increased risk of adverse pregnancy outcome seen in these patients. Accordingly, there may be a window of opportunity for improving IVF success rates and outcomes. At present, a screen-and-treat procedure to restore the normal vaginal microflora is not a routine part of the infertility work-up and treatment. While Gram staining of vaginal smears would offer an inexpensive and validated means for screening and diagnosis, probiotics that contain live lactobacilli capable of re-colonizing the vagina may offer an elegant and safe choice of treatment. Carefully designed trials using well characterized probiotic strains and treatment regimens are still required to evaluate the effect of probiotics on IVF-embryo transfer pregnancy rates.

Status of Malaria in the Kingdom of Bahrain: a 10-year review

BACKGROUND Malaria was eradicated in Bahrain about 20 years ago. However, because of a large immigrant population, cases of imported malaria continued to be seen. This paper presents an evaluation of the data from 1992 to 2001 to assess the levels of indigenous and imported malaria cases and the potential for reemergence of malaria transmission in the country. METHODS Epidemiologic and parasitologic data on confirmed malaria cases during the review period were analyzed. Data on vector breeding activity were also analyzed to determine the potential for reemergence of local transmission. RESULTS From 1992 to 2001, 1,572 cases of malaria were reported. All were imported malaria cases. There was a consistent decline in the number of cases, from 282 (the peak level) in 1992 to 54 in 2001. Eighty-four percent (1,318/1,572) of infections were contracted as a result of travel to or previous domicile in five countries, namely India, Pakistan, Sri Lanka, Bangladesh and Sudan. Plasmodium vivax was the etiologic agent in 85.6% (1,346/1,572) of cases, with Plasmodium falciparum accounting for 14% (220/1,572). During this period, the percentage of examined breeding sites where Anopheles mosquito larvae were identified remained fairly constant, ranging between 0.05% and 0.1%. CONCLUSIONS From 1992 to 2001, there was a consistent decline in the number of imported malaria cases in Bahrain. There were no cases of locally acquired malaria during this period. The low level of vector breeding spots with Anopheles mosquito larvae suggests that the potential for reemergence of local transmission remains low.

Distribution and Resistance Trends of Community Associated Urinary Tract Pathogens in Sharjah, UAE

Objective To describe the spectrum of etiologic agents causing community associated UTI and their antimicrobial resistance trends in a large teaching hospital in Sharjah, United Arab Emirates. Methods A retrospective review of the microbiology laboratory records of four hundred ninety two cases of community associated UTI between April 2006 and March 2007 was carried out. Etiologic agents and their antimicrobial susceptibility pattern were analyzed. Results A wide spectrum of uropathogens was isolated of which the leading etiologic agents of community associated UTI were Escherichia coli (207 strains) and Klebsiella species (90 strains). Sixty-six per cent of Gram-negative bacilli were resistant to amoxicillin, 58.5% were resistant to trimethoprim-sulfamethoxazole and more than 50% were resistant to cephalexin. However, resistance rate to antimicrobials like ciprofloxacin and ceftriaxone remain relatively low 9.7% and 7.6% respectively. Conclusions Escherichia coli remains the leading cause of community associated UTI. In-vitro antimicrobial resistance pattern of the isolates revealed that trimethoprim-sulfamethoxazole, cephalexin and amoxycillin the commonly used first-line antimicrobials were becoming less and less effective in their treatment. This information can help in changing preferences of suitable antimicrobial agent in treatment of community associated UTI.

Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae: In vitro Susceptibility to Fosfomycin, Nitrofurantoin and Tigecycline

Objective: To assess the susceptibility trends of community-acquired extended-spectrum β-Iactamase (ESBL)-producing urinary isolates with particular reference to fosfomycin, nitrofurantoin and tigecycline. Materials and Methods: Seven hospitals across the United Arab Emirates participated in this study from June 2008 to March 2010. The antibiotic sensitivity of ESBL-producing uropathogens to a panel of antibiotics including tigecycline, fosfomycin and nitrofurantoin was assessed. The Hyplex ESBL identification system (h-ES-ID) was used for genotypic identification. Results: Two hundred and ninety-two ESBL-producing Enterobacteriaceae isolates were identified during the study period. Of these, 182 (62%) were urinary isolates and comprised of Escherichia coli: 149 (81.9%), Klebsiella pneumoniae: 30 (16.5%) and Proteus mirabilis: 3 (1.6%). Of the 182 urinary isolates, 179 (98.3%) were from patients with community onset urinary tract infections. The h-ES-ID system identified 172 (94.5%) of the urinary isolates as CTX-M positive. All isolates were susceptible to imipenem and meropenem. Over half of the isolates showed resistance to gentamicin (98; 53.8%), trimethoprim-sulfamethoxazole (139; 76.4%) and ciprofloxacin (143; 78.6%). Sensitivity to nitrofurantoin and fosfomycin was 90 and 100%, respectively. Two CTX-M-positive K. pneumoniae isolates with tigecycline resistance (MIC >4 µg/ml) were identified. Conclusion: There is dissemination of CTX-M ESBL-producing urinary pathogens into the community. Fosfomycin and nitrofurantoin were active against ESBL-positive uropathogens, and emergence of tigecycline resistance needs close monitoring.

Pattern of Upper Respiratory Tract Infections and Physicians' Antibiotic Prescribing Practices in Bahrain

Objective: To evaluate the pattern of antibiotic prescriptions for paediatric upper respiratory tract infections (URTI) and determine the associated predictors for such antibiotic use in the Kingdom of Bahrain. Subjects and Methods: From March 2005 to March 2006, demographic data, clinical presentation, investigations and antibiotic prescription for children with URTI (n = 184) at the Bahrain Defence Force Hospital was recorded. To assess the factors which influence physician antibiotic prescription for URTI, a cross-sectional survey of doctors was carried out using a pre-tested questionnaire which was administered to paediatricians, general practitioners and emergency room physicians. Results: Antibiotics were given to 95 of the 184 (51.6%) patients, mainly children <3 years (40/95). Significant association was demonstrated for antibiotic prescription, age and diagnosis of tonsillitis or acute otitis media (p < 0.05). Amoxicillin (37/95) was the most frequently prescribed antibiotic, followed by β-lactam/β-lactamase combination and second-generation cephalosporins. Fever, younger age, sore throat and presence of earache increased the likelihood of antibiotic prescription. Data from the cross-sectional survey of doctors revealed that lack of national guidelines, parental pressure and diagnostic uncertainty contributed to antibiotic overuse. Conclusion: Antibiotic overuse for the treatment of paediatric URTI remains a problem in our setting. We suggest the development of national guidelines which are integrated with structured continuing medical education courses, public awareness campaigns and the introduction of rapid streptococcal antigen tests in the outpatient clinic.

Probiotics in the Arabian Gulf Region

Objective Available reports on adherence to recommended guidelines for labeling of probiotic products are based on assessment of these products in developed countries. In the Arabian Gulf region, there is a paucity of data on the characterization of probiotic products and an absence of local guidelines for their labeling. This study, carried out in the United Arab Emirates (UAE), represents the first evaluation of probiotic products available in the Arabian Peninsula. Methods Probiotic products were purchased over the counter from a variety of sources, including pharmacies, healthfood stores, and supermarkets across the UAE. All identified products were listed and information regarding type of product preparation and labeling information were recorded. Results A total of 37 probiotic products, 15 dairy-based and 22 non-dairy-based were identified. The dairy products comprised of 12 yogurts, two fermented milk products and one powdered baby formula. The majority of non-dairy products were in capsule form (n = 16). While all the non-dairy products gave information about the strain of probiotic microorganism and number present at time of manufacture, this information was provided for only one dairy-based product. Strains of Lactobacillus acidophilus were the most common probiotic organisms identified. However, one probiotic product listed Enterococcus faecalis (750 million viable bacteria per capsule) as a component. With the exception of one non-dairy-based product, all health-related claims were structure/function statements, according to the US Food and Drug Administration nomenclature. Conclusion These findings indicate that a wide variety of probiotic products are available in the Arabian Gulf. Development of guidelines for labeling of these probiotic products and use of structure/function statements and health claims should be addressed.

Antibiotic therapeutic options for infections caused by drug-resistant Gram-positive cocci

Serious infections caused by Gram-positive bacteria are currently difficult to treat because many of these pathogens are now resistant to standard antimicrobial agents. As a result of the emergence and spread of multidrug-resistant Gram-positive pathogens, new antimicrobial agents are urgently needed for clinical use. In recent years, there has been an increase in the number of drugs that have activity against these Gram-positive pathogens. Daptomycin, tigecycline, linezolid, quinupristin/dalfopristin and dalbavancin are five antimicrobial agents that are useful for the treatment of infections due to drug-resistant Gram-positive cocci. This review focuses on their mechanism of action, pharmacokinetics, spectrum of activity, clinical effectiveness, drug interaction and safety. These antimicrobial agents provide the clinician with additional treatment options among the limited therapies for resistant Gram-positive bacterial infection.

Trafficking of methicillin-resistant staphylococci and co-colonization with vancomycin-resistant enterococci.

Objectives: To determine the trafficking of methicillin-resistant staphylococci between the hospital and community as well as the occurrence of co-colonization with vancomycin-resistant enterococci (VRE). Subjects and Methods: From November 2005 to April 2006, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MRCoNS)-positive patients at the Salmaniya Medical Complex, Bahrain were assessed for VRE co-colonization. Characterization of vancomycin resistance genotype by PCR was carried out. Close family contacts were screened for MRSA and pulsed-field gel electrophoresis (PFGE) analysis of MRSA isolates from patient-family member pairs was conducted. Results: One hundred and eighty-two patients (93 MRSA; 89 MRCoNS) and 356 family members were enrolled. Seven MRSA and 41 MRCoNS strains were isolated from the family members. PFGE analysis revealed the presence of variants of a single MRSA clone among patients and their relatives. A total of 112 patients (62 MRSA; 50 MRCoNS) provided stool for VRE screening. Of these 13 stool specimens (11.6%) were VRE-positive. All the VRE isolates were from MRSA-positive patients, thus positivity rate among MRSA patients was 20.9% (n/N = 13/62). These were predominantly Enterococcus gallinarum with vanC1 genotype and one strain was Enterococcus faecium (vanB genotype). Two E. gallinarum isolates harbored an additional vanB gene. The majority of VRE isolates were from patients in medical and surgical units (n/N = 10/13; 77%). Male gender, prolonged hospitalization and presence of co-morbidities were significantly associated with MRSA/VRE co-colonization (p < 0.05). Conclusion: MRSA/VRE co-colonization with MRSA trafficking between the hospital and community environment is a public health concern occurring in our setting.