Dolla Karam Sarkis

Countrywide Spread of Community- and Hospital-Acquired Extended-Spectrum β-Lactamase (CTX-M-15)-Producing Enterobacteriaceae in Lebanon

ABSTRACT A prospective study was carried out to assess the extent of carriage of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae at both hospital and community levels in Lebanon. A total of 1,442 fecal samples were collected from hospital-based patients and 58 from health care workers of six Lebanese tertiary care general hospitals located in different areas of Lebanon between January and March 2003. A total of 382 fecal samples were also collected from healthy subjects between April and June 2003. The samples analysis led to the identification of 118 strains as ESBL producers based on the synergistic effects between clavulanate and selected β-lactams (ceftazidime and cefotaxime). These strains were isolated from 72 subjects: 61 patients, 2 health care workers, and 9 healthy subjects. One representative strain per subject was selected, and a total of 72 nonduplicate ESBL producers, including a high majority of Escherichia coli (n = 56), Klebsiella pneumoniae (n = 9), Enterobacter cloacae (n = 6), and Citrobacter freundii (n = 1), were characterized. The molecular analysis revealed that the majority of the strains (83%) express CTX-M-15 ESBL (pI 8.6). SHV-5a ESBL (pI 8.2) was produced by 18% of the strains. DNA macrorestriction analysis of ESBL-producing E. coli presented 38 different genotypes, revealing the absence of clonal link among these strains. In addition to the fact that the present study highlights the emergence and the countrywide dissemination of CTX-M-15-producing E. coli in Lebanon, it represents the first report of an SHV-5a-producing C. freundii.

Susceptibility trends and molecular characterization of Gram-negative bacilli associated with urinary tract and intra-abdominal infections in Jordan and Lebanon: SMART 2011-2013.

OBJECTIVES To investigate phenotypic and genotypic patterns of antimicrobial resistance among Gram-negative bacilli associated with urinary tract infection (UTI) and intra-abdominal infection (IAI) in medical centres of Jordan and Lebanon. METHODS Gram-negative bacilli from the SMART study, collected between the years 2011 and 2013, were first identified at local laboratories. These isolates were shipped to a central laboratory where re-identification, susceptibility testing, and molecular characterization were performed using standard methods. RESULTS Among the 523 UTI-associated isolates, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were the most frequent (70%, 14%, and 5%, respectively). E. coli, K. pneumoniae, and Pseudomonas aeruginosa were the most frequent species among the 527 IAI-associated isolates (46%, 14%, and 12%, respectively). Incidence rates of extended-spectrum beta-lactamase (ESBL) producers among UTI-associated E. coli, K. pneumoniae, and P. mirabilis were 43%, 54%, and 4%, respectively. Corresponding rates among IAI-associated isolates were 49%, 56%, and 12%, respectively. Acinetobacter baumannii and P. aeruginosa isolates showed very disturbing low susceptibility patterns. CTX-M-15 was the most prevalent ESBL produced. Seventeen isolates were non-susceptible to carbapenems (estimated prevalence of 1.6%). CONCLUSIONS The alarmingly high rates of ESBL production and emergence of carbapenemases emphasize the urgent need to develop antimicrobial stewardship initiatives and to maintain antimicrobial resistance surveillance systems.

Mycobacterial infection of breast prosthesis – a conservative treatment: a case report

BackgroundBacterial infection is a well-known risk of breast implant surgery. It is typically caused by bacterial skin flora, specifically Staphylococcus aureus and the coagulase negative staphylococci. There have been infrequent reports of breast implant infection caused by the atypical mycobacteria, of which Mycobacterium canariasense not yet reported in the literature.Case presentationThis report summarizes the case of a female patient who underwent mastectomy followed by bilateral breast augmentation and presented approximately three years later with clinical evidence of infected breast prosthesis by Mycobacterium canariasense. One year after thoroughly follow-up, appropriate antibiotherapy and the change of the infected prosthesis, the patient presented no signs of reinfection.ConclusionOur case demonstrates that Mycobacterium canariasense should be considered as a new potential cause of infected breast prosthesis.

In vitro Evaluation of the Colistin-Carbapenem Combination in Clinical Isolates of A. baumannii Using the Checkerboard, Etest, and Time-Kill Curve Techniques

The worldwide increase in the emergence of carbapenem resistant Acinetobacter baumannii (CRAB) calls for the investigation into alternative approaches for treatment. This study aims to evaluate colistin-carbapenem combinations against Acinetobacter spp., in order to potentially reduce the need for high concentrations of antibiotics in therapy. This study was conducted on 100 non-duplicate Acinetobacter isolates that were collected from different patients admitted at Saint George Hospital-University Medical Center in Beirut. The isolates were identified using API 20NE strips, which contain the necessary agents to cover a panel of biochemical tests, and confirmed by PCR amplification of blaOXA−51−like. Activities of colistin, meropenem and imipenem against Acinetobacter isolates were determined by ETEST and microdilution methods, and interpreted according to the guidelines of the Clinical and Laboratory Standards Institute. In addition, PCR amplifications of the most common beta lactamases contributing to carbapenem resistance were performed. Tri locus PCR–typing was also performed to determine the international clonality of the isolates. Checkerboard, ETEST and time kill curves were then performed to determine the effect of the colistin-carbapenem combinations. The synergistic potential of the combination was then determined by calculating the Fractional Inhibitory Concentration Index (FICI), which is an index that indicates additivity, synergism, or antagonism between the antimicrobial agents. In this study, 84% of the isolates were resistant to meropenem, 78% to imipenem, and only one strain was resistant to colistin. 79% of the isolates harbored blaOXA−23−like and pertained to the International Clone II. An additive effect for the colistin-carbapenem combination was observed using all three methods. The combination of colistin-meropenem showed better effects as compared to colistin-imipenem (p < 0.05). The colistin-meropenem and colistin-imipenem combinations also showed a decrease of 2.6 and 2.8-fold, respectively in the MIC of colistin (p < 0.001). Time kill assays additionally showed synergistic effects for a few isolates, and no bacterial re-growth was detected following a 24 h incubation. Our study showed that the combination of colistin with carbapenems could be a promising antimicrobial strategy in treating CRAB infections and potentially lowering colistin toxicity related to higher doses used in colistin monotherapy.

SURVEILLANCE of CARBAPENEM NON-SUSCEPTIBLE GRAM NEGATIVE STRAINS and CHARACTERIZATION of CARBAPENEMASES of CLASSES A, B and D in a LEBANESE HOSPITAL.

The production of carbapenem-hydrolyzing enzymes has been recognized as one of the most currently relevant resistance mechanisms in gram negative bacterial isolates, and is being detected in various countries. In Lebanon, carbapenem resistance was studied among gram negative pathogens collected from a university hospital from January to June of years 2011 and 2012. All isolates were subjected to phenotypic tests including antibiotic susceptibility, cloxacillin effect, modified Hodge test, and Etest for metallo-β-lactamase detection. They were also subjected to genotyping by PCR sequencing to characterize β-lactamases. Between January and June 2011, 48 carbapenem non-susceptible strains were collected. Of these, one Klebsiella pneumoniae harbored OXA-48 and insertion sequence IS 1999; four Acinetobacter baumanni harbored simultaneously OXA-23 and GES-11, and three Pseudomonas harbored VIM-2 carbapenemase. Between January and June 2012, 100 carbapenem non-susceptible strains were collected. Of these, one K. pneumoniae harbored simultaneously OXA-48, IS 1999, and an acquired AmpC of the ACC group; four Serratia marcescens harbored OXA-48, while among eight A. baumannii, one strain co-harbored OXA-23 and GES-11, six harbored OXA-23 and one OXA-24. Fifteen P, aeruginosa and two Pseudomonas species harbored VIM-2; two P. aeruginosa strains produced IMP-1 and two others IMP-2. This epidemiological survey demonstrates the presence of carbapenemases of Ambler classes A, B, and D in a Lebanese hospital and indicates increase in the number and variety of such enzymes.

Clonal emergence of Klebsiella pneumoniae ST14 co-producing OXA-48-type and NDM carbapenemases with high rate of colistin resistance in Dubai, United Arab Emirates

Few studies have addressed the molecular epidemiology of carbapenem-resistant Enterobacteriaceae (CRE) isolates in the Arabian Peninsula, and such investigations have been missing from Dubai, a major economical, tourism and medical centre of the region. The antibiotic susceptibility, the carbapenemase type produced, and the clonality of 89 CRE strains isolated in five major Dubai hospitals in June 2015 to June 2016 were determined. Thirty-three percent of the collection of 70 Klebsiella pneumoniae, 13 Escherichia coli and 6 other Enterobacteriaceae were extremely drug resistant, 27% were resistant to colistin, and 4.5% (4 K. pneumoniae isolates) were resistant to all antibiotics tested. The colistin resistance rate in K. pneumoniae was 31.4%. None of the isolates carried mobile colistin resistance genes. Seventy-seven isolates produced carbapenemase: 53.3% OXA-48-like, 24.7% NDM and 22.1% both OXA-48-like and NDM, respectively. Pulsed-field gel electrophoresis clustered 50% of K. pneumoniae into a 35-membered group, which showed significant association with double carbapenemase production, with extreme drug resistance, and with being isolated from Emirati patients. Members of the cluster belonged to sequence type ST14. The rate of colistin resistance in K. pneumoniae ST14 was 37.1% vs. 27.1% of K. pneumoniae isolates outside of the cluster. Two of the panresistant K. pneumoniae isolates also belonged to ST14, whereas the other two were ST15 and ST231, respectively. In conclusion, beyond the overall high colistin resistance rate in CRE, the emergence of a highly resistant clone of K. pneumoniae ST14 in all Dubai hospitals investigated is a serious problem requiring immediate attention.

Phenotypic and genotypic detection of beta lactamases in Acinetobacter spp. isolates recovered from Lebanese patients over a period of one year

OBJECTIVES The aim of this study was to determine the prevalence of β-lactamases in Acinetobacter spp. recovered from Lebanese patients over a 1-year period using phenotypic and molecular methods. METHODS A total of 100 non-duplicate consecutive Acinetobacter spp. isolates were collected from various clinical specimens. Antimicrobial susceptibility testing was performed by the disk diffusion method. Susceptibility to colistin, imipenem and meropenem was determined by broth microdilution. The β-lactamase inhibitors phenylboronic acid, cloxacillin and ethylene diamine tetra-acetic acid (EDTA) were used for presumptive detection of KPC-type β-lactamase, AmpC β-lactamase and metallo-β-lactamase (MBL), respectively. Simplex PCR was conducted for molecular detection of β-lactamases. Trilocus PCR typing was performed to determine the clonality of the isolates. RESULTS Among the 100 Acinetobacter spp. isolates, 78% were resistant to imipenem and 84% to meropenem. Only one isolate was resistant to colistin by the microdilution method. Phenotypically, 23% of the isolates were presumptively diagnosed as producing extended-spectrum β-lactamase (ESBL), 15% as producing KPC and 4% MBL, whilst 5% were diagnosed as overproducing AmpC β-lactamase. The blaOXA-51-like gene was detected in 99% of isolates, blaADC in 93%, blaOXA-23-like in 77% and blaOXA-24/40-like in 3%. Trilocus PCR identified 86% (82/95) of the Acinetobacter baumannii isolates as international clone II (IC II). CONCLUSIONS A high rate of carbapenem resistance, with a predominance of OXA-23-like and IC II, was shown in this study. Moreover, the inhibitor-based method was shown not to be accurate for the prediction of carbapenemases in A. baumannii.

Carbapenem-Resistant, Gram-Negative Bacilli: The State of the Art

The evolution of antimicrobial resistance in bacteria is a complex and longstanding process that has gathered much attention by outpacing the discovery and development of new antibiotics. Among Gram-negative bacilli, resistance has been progressive and unremitting in Enterobacteriaceae, Pseudomonas aeruginosa , and Acinetobacter baumannii . In particular, the spread of carbapenem-resistant, Gram-negative bacilli during the last decade has escalated worldwide, resulting in severe infections, some of which respond to only a few therapeutic options. Often viewed as last-resort antibiotics, carbapenems are rendered inactive against bacteria via the production of carbapenem-hydrolyzing enzymes, utilization of impermeable cell wall porins, active expulsion of carbapenem molecules by efflux pumps, production of mutant penicillin-binding proteins, or a combination. This chapter describes the mechanisms and epidemiology of resistance to carbapenems in Gram-negative pathogens. It also sheds a light on laboratory detection of these pathogens and presents available control and therapeutic options for their containment.The evolution of antimicrobial resistance in bacteria is a complex and longstanding process that has gathered much attention by outpacing the discovery and development of new antibiotics. Among Gram-negative bacilli, resistance has been progressive and unremitting in Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii. In particular, the spread of carbapenem-resistant, Gram-negative bacilli during the last decade has escalated worldwide, resulting in severe infections, some of which respond to only a few therapeutic options. Often viewed as last-resort antibiotics, carbapenems are rendered inactive against bacteria via the production of carbapenem-hydrolyzing enzymes, utilization of impermeable cell wall porins, active expulsion of carbapenem molecules by efflux pumps, production of mutant penicillin-binding proteins, or a combination. This chapter describes the mechanisms and epidemiology of resistance to carbapenems in Gram-negative pathogens. It also sheds a light on laboratory detection of these pathogens and presents available control and therapeutic options for their containment.

Bacterial Flora of Normal Maxillary Sinuses in Adults

Objective (1)To determine the bacterial flora and (2) to quantify the level of bacterial presence in healthy maxillary sinus cavities. Methods Subjects included 25 consecutive patients undergoing Lefort I osteotomy for orthognathic surgery under general anesthesia between January 2007 and February 2008. All patients were preoperatively evaluated by a questionnaire and a complete physical examination including sinus endoscopy. Our exclusion criteria were: presence of sinonasal symptoms, asthma, antibiotic treatment in the past 3 months, treatment with local steroids, previous sinonasal surgery, traumatic surgery, and an abnormal sinus endoscopy. Washes were obtained from maxillary sinuses before surgery through an antral puncture. The sinus was irrigated with 1cc of sterile saline followed by aspiration with a syringe attached to the trocar. Basic sterility rules were rigorously applied. Specimens were transported to the laboratory in a sealed, airfree syringe. Time between collection of materials and inoculation of the specimen did not exceed 15 minutes. Specimens were inoculated for aerobic and anaerobic organisms. Results After applying the selection criteria, 14 patients (28 sinuses) remained. Eight (57.1%) were males with a mean age of 22.7 years. 82.14% of the specimens were sterile. Bacterial organisms were recovered in only 4 patients with 2 different coagulase negative staphylococci in the same patient: one in each sinus with 200UFC/ml in the left sinus and 10UFC/ml in the right sinus, 1 citrobacter fundii (70 UFC/ml) and 2 polymorphic floras. Conclusions This descriptive study demonstrates the large predominance of sterile maxillary sinus cavities in asymptomatic adults with endoscopically normal mucosa.