Eiman Mokaddas - Academia.edu (original) (raw)

Papers by Eiman Mokaddas

BMC infectious diseases, 2006

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a major cause of serious infec... more Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a major cause of serious infections in hospitals and in the community worldwide. In this study, MRSA isolated from patients in Kuwait hospitals were analyzed for resistance trends and the genetic location of their resistance determinants. Between April 1994 and December 2004, 5644 MRSA isolates obtained from different clinical samples were studied for resistance to antibacterial agents according to guidelines from the National Committee for Clinical Laboratory Standards and the British Society for Antimicrobial Chemotherapy. The genetic location of their resistance determinants was determined by curing and transfer experiments. They were resistant to aminoglycosides, erythromycin, tetracycline, trimethoprim, fusidic acid, ciprofloxacin, chloramphenicol, rifampicin, mupirocin, cadmium acetate, mercuric chloride, propamidine isethionate and ethidium bromide but susceptible to vancomycin, teicoplanin and linezolid. The ...

Journal of clinical microbiology, 2004

Isolates of Candida dubliniensis may be misidentified as Candida albicans in microbiological labo... more Isolates of Candida dubliniensis may be misidentified as Candida albicans in microbiological laboratories if only the germ tube and/or the chlamydospore test is used for identification to the species level. In this study, we have evaluated the efficacy of tobacco agar for the differentiation of C. dubliniensis from C. albicans. On this medium at 28 degrees C, all 30 C. dubliniensis isolates produced yellowish-brown colonies with hyphal fringes and abundant chlamydospores, whereas 54 C. albicans isolates formed smooth, white-to-cream-colored colonies with no chlamydospore production. This medium provides a simple tool for presumptive differentiation of C. dubliniensis from C. albicans.

International journal of antimicrobial agents, 2005

Mutations associated with rifampicin (RIF) resistance in two regions of the rpoB gene were studie... more Mutations associated with rifampicin (RIF) resistance in two regions of the rpoB gene were studied by line probe (INNO-LiPA Rif. TB) assay (LiPA) and/or DNA sequencing in 32 RIF-resistant and 21 RIF-susceptible Mycobacterium tuberculosis strains isolated from 53 tuberculosis patients in Kuwait. The LiPA identified all susceptible strains as RIF sensitive, and the DNA sequences of the 81bp rifampicin resistance-determining region (RRDR) and the N-terminal region of the rpoB gene from five isolates were identical to the wild-type sequences from M. tuberculosis H(37)Rv. The LiPA identified 24 of 32 (75%) phenotypically documented RIF-resistant M. tuberculosis isolates as RIF resistant, with specific detection of mutation in 19 isolates, whilst 8 strains were identified as RIF susceptible. DNA sequencing of the RRDR confirmed the results for the 19 RIF-resistant isolates and identified precise mutations in five isolates for which specific base changes could not be determined by LiPA, as...

Japanese journal of infectious diseases, 2007

Most mycobacterial infections are still caused by Mycobacterium tuberculosis complex (MTC) strain... more Most mycobacterial infections are still caused by Mycobacterium tuberculosis complex (MTC) strains; however, infections by non-tuberculous mycobacteria (NTM) are increasing, particularly among immunocompromised patients. Conventional species-specific identification and proper patient management are delayed due to the slow-growing nature of mycobacteria. We have developed a multiplex PCR (mPCR) targeting the oxyR-ahpC intergenic region and rpoB gene for direct detection and differentiation of clinical isolates as MTC or NTM in primary culture. Two amplicons of 473 bp and 235 bp from MTC members and a single amplicon of 136 bp from NTM are expected. The mPCR was developed using several mycobacterial species and was evaluated by testing extracted DNA from liquid cultures, flagged as positive for bacterial growth, of 100 consecutive mycobacterial isolates. The results were validated by DNA sequencing of the species-specific 16S-23S internal transcribed spacer (ITS) region. The mPCR with...

A case of cerebral aspergillosis was diagnosed by the detection of Aspergillus flavus-specific DN... more A case of cerebral aspergillosis was diagnosed by the detection of Aspergillus flavus-specific DNA in brain biopsy and serum specimens. The diagnosis was also supported by detection of elevated levels of galactomannan and (1R3)-b-D-glucan in serum specimens. Despite the presence of dichotomously branched septate hyphae in brain biopsy, the culture remained negative. The inability to isolate the organism in culture suggested that combined therapy of AmBisome and caspofungin was fungicidal for the fungus in the brain abscess.

Microbiology and Immunology, 2002

Journal of clinical microbiology, Jan 21, 2015

Among 452 Xpert MTB/RIF (Xpert) and MGIT 960 system (MGIT) positive samples, 440 and 10 Mycobacte... more Among 452 Xpert MTB/RIF (Xpert) and MGIT 960 system (MGIT) positive samples, 440 and 10 Mycobacterium tuberculosis were detected as rifampin-susceptible and rifampin-resistant, respectively. Two rifampin-susceptible isolates by MGIT were rifampin-resistant by Xpert. rpoB sequencing identified a silent (CTG521TTG) mutation in one and a missense (GAC516TAC) mutation in another isolate. Detection of rifampin resistance is imperfect with both, Xpert and MGIT. Any discordant rifampin resistance should be confirmed by sequencing of the rpoB gene.

Mycoses, 2011

Despite close genetic and phenotypic relationship of Candida dubliniensis with Candida albicans, ... more Despite close genetic and phenotypic relationship of Candida dubliniensis with Candida albicans, its role in human disease is mostly restricted to oral colonisation, particularly among HIV-infected patients. The prevalence of C. dubliniensis in association with other disease conditions has been infrequently reported. In this study, we present data on the prevalence of C. dubliniensis among yeast species isolated from cancer patients over a 5-year period. A total of 1445 yeast isolates recovered from respiratory specimens, blood, urine and oral swabs were analysed. Candida dubliniensis isolates were provisionally identified by phenotypic methods and their identity was further confirmed by speciesspecific amplification and ⁄ or sequencing of internally transcribed spacer region of rDNA. Antifungal susceptibility for fluconazole was determined by Etest. The number of isolates identified as C. dubliniensis, C. albicans and other yeast species were 71 (4.9%), 862 (59.6%) and 512 (35%) respectively. All the C. dubliniensis isolates originated from respiratory (5.9%) or oral (3.2%) specimens with an overall prevalence of 4.9%, and were found to be susceptible to fluconazole. The isolation of C. dubliniensis from respiratory or oral specimens and not from blood or urine specimens suggests that this species has preference to colonise these sites of human body.

Journal of Medical Microbiology, 2007

Objectives: To establish the species distribution and in vitro susceptibilities of 358 bloodstrea... more Objectives: To establish the species distribution and in vitro susceptibilities of 358 bloodstream fungal isolates from paediatric patients in Mexico.

Journal of Infection and Public Health, 2014

The global burden of tuberculosis (TB) is still large. The increasing incidence of drug-resistant... more The global burden of tuberculosis (TB) is still large. The increasing incidence of drug-resistant, multidrug-resistant (MDR) (resistant to at least rifampicin and isoniazid), and extensively drug-resistant (XDR) (additionally resistant to a fluoroquinolone and kanamycin/amikacin/capreomycin) strains of Mycobacterium tuberculosis and the association of active disease with human immunodeficiency virus coinfection pose a major threat to TB control efforts. The rapid detection of M. tuberculosis strains and drug susceptibility testing (DST) for anti-TB drugs ensure the provision of effective treatment. Rapid molecular diagnostic and DST methods have been developed recently. Treatment of drug-susceptible TB is effective in ≥95% of disease cases; however, supervised therapy for ≥6 months is challenging. Nonadherence to treatment often results in the evolution of drug-resistant strains of M. tuberculosis due to mutations in the genes encoding drug targets. Sequential accumulation of mutations results in the evolution of MDR and XDR strains of M. tuberculosis. Effective treatment of MDR-TB involves therapy with 5-7 less effective, expensive, and toxic second-line and third-line drugs for ≥24 months and is difficult in most developing countries. XDR-TB is generally an untreatable disease in developing countries. Some currently existing drugs and several new drugs with novel modes of action are in various stages of development to shorten the treatment duration of drug-susceptible TB and to improve the outcome of MDR-TB and XDR-TB.

International Journal of Antimicrobial Agents, 2004

The presence of ACC and other mutations at codon 315 in the katG gene was detected by PCR amplifi... more The presence of ACC and other mutations at codon 315 in the katG gene was detected by PCR amplification followed by restriction fragment length polymorphism (PCR-RFLP) generated with restriction enzymes Msp I and MspA1 I in 37 isoniazid-resistant and 22-susceptible Mycobacterium tuberculosis isolates from Kuwait obtained in 2001. The mutation AGC to ACC was detected in 22 (60%) isolates while any mutation at codon 315 of the katG gene was present in 24 (65%) of 37 isoniazid-resistant isolates. The typing studies showed that majority of the isolates carrying mutations at codon 315 exhibited unique DNA banding patterns. The results were extended by additional analysis of 67, 28 and 17 isoniazid-resistant and 18, seven and six-susceptible M. tuberculosis isolates from Kuwait, Dubai and Beirut, respectively, that were analyzed previously for ACC mutation alone. These studies showed that one of 21, one of 10 and two of 11 isolates (all recovered from patients of Middle Eastern origin) with no AGC to ACC mutation from Kuwait, Dubai and Beirut, respectively, contained other mutations at codon 315 of the katG gene. None of the susceptible strains contained any mutation at codon 315. The PCR-RFLP with MspA1 I that detects all mutations at codon 315, compared with Msp I that detects only ACC mutation, identified more isoniazid-resistant strains with mutations at codon 315 in the katG gene. The data also showed that mutations other than AGC to ACC at codon 315 in the katG gene occur frequently in M. tuberculosis isolates recovered from Middle Eastern patients and should be incorporated in a rapid screen for the detection of mutations for isoniazid-resistance in the katG gene from this ethnic group.

Current Microbiology, 2008

Identification of Mycobacterium species is difficult due to a complex and rapidly changing taxono... more Identification of Mycobacterium species is difficult due to a complex and rapidly changing taxonomy, the failure of 16S rRNA to discriminate many closely related species and the unreliability of phenotypic testing. We investigated a collection of nontuberculous mycobacteria (NTM) strains isolated from suspected tuberculosis patients at Tuberculosis Reference Centre (Ahvaz, Iran) and Masoud Laboratory (Tehran, Iran) during 2008-2012 to evaluate the species spectrum of NTM isolates.

Clinical Microbiology and Infection, 2004

This study evaluated sunflower (Helianthus annuus) seed agar (SSA) for differentiation of Candida... more This study evaluated sunflower (Helianthus annuus) seed agar (SSA) for differentiation of Candida dubliniensis from Candida albicans on the basis of colony characteristics and chlamydospore production. Simplified SSA without creatinine and KH(2)PO(4) was also used. On both media, C. dubliniensis isolates (n = 25) developed rough colonies and formed abundant chlamydospores after incubation for 24-48 h at 28 degrees C, while C. albicans isolates (n = 53) showed smooth colonies with no evidence of chlamydospore formation. Cryptococcus neoformans isolates (n = 10) formed brown colonies on both media. Simplified SSA offers a simple and inexpensive tool for presumptive differentiation of C. dubliniensis from C. albicans in clinical microbiology laboratories.

Burns, 1998

Out of 943 patients treated from June 92 to May 96 at the burns unit of the Al-Babtain Centre for... more Out of 943 patients treated from June 92 to May 96 at the burns unit of the Al-Babtain Centre for Plastic Surgery and Burns, Kuwait, 280 (30%) required admission to the burns intensive care unit (ICBU) and were studied retrospectively. Seventy-nine (28.2%) developed clinically and microbiologically proven septicaemia. Forty-four (56%) were males, 35 (44%) females with a mean age of 26 years (range 45 days to 75 years) and mean total body surface area burn (TBSA) of 46% (range 10-90%). Sixty-two had flame burns, 16 a scald and one had an electric burn. These 79 patients had a total of 118 septicaemic episodes. Sixty (76%) had only one and 19 (24%) had multiple episodes of septicaemia. Fifty-four (68%) had their first episode within 2weeks, though the maximum number of episodes was between 6 and 10 days postburn. Septicaemia was also observed in 13% of patients within 3 days postburn. Out of the 118 episodes, 48 were due to methicillin resistant Staphylococcus aureus (MRSA), 17 due to methicillin resistant Staphylococcus epidemidis (MRSE), 15 to Pseudomonas, 12 to Acinetobacter, four to Streptococcus, another four to Enterococci, two to Klebsiella, one due to Serratia and 15 to more than one organism. Once the septicaemia was diagnosed appropriate therapy was instituted. Fifty-six (71%) patients had 143 sessions of skin grafting and the mortality was low in operated patients. Twenty-three (29.1%) patients died. The low mortality rate was probably due to factors such as continuous clinical and microbiological surveillance leading to quick detection of aetiology, appropriate antibiotic therapy, care for nutrition and early wound cover. This study suggests that flame burn patients are more vulnerable to sepsis. Onset of septicaemia may be as early as 3 days and commonly within 2 weeks. A surface wound is the likely source of entry to the blood stream. Gram positive organisms are dominant in the aetiology. Early detection and appropriate treatment including wound coverage result in a better outcome.

Burns, 2001

This study analyses staphylococcal septicaemia in a series of 1516 burn patients who were admitte... more This study analyses staphylococcal septicaemia in a series of 1516 burn patients who were admitted to the burn unit of the Al-Babtain Centre for Burns and Plastic Surgery, Ibn Sina Hospital, Kuwait over a period of 6.5 years (1 June 1992-31 December 1998). One hundred and nine patients (7.2%) developed clinically and microbiologically proven septicaemia, of which 80 (73.4%) showed one or the other type of Staphylococcus in their blood. Fifty (62.5%) of them were males and 30 (37.5%) females, with a mean age of 26 years and the mean total body surface area of burns (TBSA) of 45% (range 1-93%). Preschool age children comprised 27.5% of the patients. Flame was the dominant (80%) cause of burn. Of the 80 patients who had 91 episodes of septicaemia, 52 (65%) had MRSA, 8 (10%) MSSA, 11 (13.8%) MRSE and 5 (6.2%) MSSE and 4 (5%) others had mixed organisms. Only the patients with MRSA had multiple episodes. Eight patients (10%) showed septicaemic episodes within only 48 h of admission; however, the majority of the patients (77.5%) had a septicaemic attack within 2 weeks postburn. Of the 52 MRSA septicaemic cases, 39 (75%) survived and 13 (25%) died. Four patients with septicaemia due to mixed infections died. A total of 19 patients were intubated, 14 due to inhalation injury and 5 because of septicaemia; all in the former group died. Glycopeptide therapy (vancomycin/teicoplanin) was instituted immediately following the detection of staphylococci in the blood. No significant difference was noted in relation to mortality amongst the septicaemic patients, whether or not on prophylactic antibiotic. Fifty-six (70%) of the 80 patients had 139 sessions of skin grafting and survived. Of the 52 MRSA patients, 40 had 101 sessions of skin grafting and 33 of them survived. The apparent low mortality was probably due to early detection of the organism, appropriate antibiotic therapy, care for nutrition and early wound cover. This study indicates a high incidence of staphylococcal septicaemia (especially due to MRSA) in the burn unit. A surface wound is the likely source of entry to the blood stream in these immunocompromised patients. The organism could be detected in blood as early as 48 h postburn and in as little TBSA burn as 1% in this MRSA endemic unit. Inhalation injury with major burns and added staphylococcal septicaemia invariably proved to be fatal.

BMC Infectious Diseases, 2010

Background: Surveillance cultures may be helpful in identifying patients at increased risk of dev... more Background: Surveillance cultures may be helpful in identifying patients at increased risk of developing invasive candidiasis. However, only scant information exists on the effect of Candida colonization on serum levels of diagnostic biomarkers. This prospective surveillance study determined the extent of Candida colonization among pediatric cancer patients and its possible impact on serum levels of (1-3)-β-D-glucan (BDG), Candida mannan and Candida DNA. Methods: A total of 1075 swabs originating from oropharynx (n = 294), nostrils (n = 600), rectum (n = 28), groin (n = 50), ear (n = 54), and axilla (n = 49) of 63 pediatric cancer patients were cultured for the isolation of Candida spp. Patients yielding Candida spp. from any sites were considered as colonized. Serum samples were collected from patients at the time of first surveillance culture for detection of BDG by Fungitell kit and Candida mannan by Platelia Candida Ag. Candida DNA was detected by using panfungal primers and identification was carried out by using species-specific primers and DNA sequencing. Results: Seventy-five (7.6%) swab cultures from 35 (55.5%) patients yielded Candida spp. These isolates included C. albicans (n = 62), C. dubliniensis (n = 8), C. glabrata and C. tropicalis (n = 2 each) and C. krusei (n = 1). Eleven patients were colonized at three or more sites. Eight of 36 serum samples from 6 colonized patients yielded BDG values higher than the currently recommended cut-off value of ≥80 pg/ml. However, none of the serum samples yielded Candida mannan levels ≥0.5 ng/ml and PCR test for Candida DNA was also negative in all the serum samples of colonized patients. During the study period, only two colonized patients subsequently developed candidemia due to C. tropicalis. Besides positive blood cultures, C. tropicalis DNA, BDG and Candida mannan were also detected in serum samples of both the patients. Conclusions: The present study demonstrates that while mucosal colonization with Candida species in pediatric cancer patients is common, it does not give rise to diagnostically significant levels of Candida mannan or Candida DNA in serum specimens. However, BDG values may be higher than the cut-off value in some pediatric patients without clinical evidence of invasive Candida infection. The study suggests the utility of Candida mannan or Candida DNA in the diagnosis of invasive candidiasis, however, the BDG levels in pediatric cancer subjects should be interpreted with caution.

Annals of Clinical Microbiology and Antimicrobials, 2009

Background: Ethambutol (EMB) is a first-line drug for the treatment of tuberculosis (TB). Resista... more Background: Ethambutol (EMB) is a first-line drug for the treatment of tuberculosis (TB). Resistance to EMB in Mycobacterium tuberculosis isolates is mediated by mutations in several genes involved in arabinan synthesis notably three emb (arabinosyl transferase) and iniA (isoniazidinducible) genes. Most epidemiologically unrelated EMB-resistant M. tuberculosis strains contain mutations at embB codons 306, 406 and 497, embC-embA intergenic region (IGR) and iniA codon 501 (iniA501).

Antonie van Leeuwenhoek, 2008