Genomic Characterization of MDR Escherichia coli Harboring blaOXA-48 on the IncL/M-type Plasmid Isolated from Blood Stream Infection

Escherichia coli is responsible for a wide variety of community and hospital acquired extraintestinal infections, and the emergence of ESBL resistant isolates is a major clinical concern. In this study, we characterized the genomic attributes of an OXA-48 and CTX-M-3 producing E. coli EC-IMP153. Whole-genome initial assembly produced 146 contigs with a combined 5,504,170 bp in size and a G+C content of 50.5%. wgSNPs-based phylogenetic comparison with 36 publically available genomes was also performed. Comprehensive genomic analysis showed that EC-IMP153 belonged to sequence type ST-405 and harbored several resistance determinants including the β-lactam resistance genes blaOXA-48, blaCTX-M-3, blaTEM-1B, blaOXA-1, and blaCMY-70, aminoglycoside fyuA and aac(3)IId, tetracycline tet(A) and tet(R), and fluoroquinolone gyrA, parC, and mfd resistance determinants. Plasmids with the following incompatibility groups were detected in silico and confirmed using PBRT: IncI1-α, IncL, IncW, Col (BS512), and IncF. To our knowledge this is the first in-depth genomic analysis of an OXA-48 producing E. coli ST-405 isolated from a patient in Lebanon and linked to a blood stream infection. Continuous monitoring is necessary to better understand the continued diffusion of such pathogens, especially in view of the population movements triggered by unrest in the Middle East.

First detection and sequence analysis of thebla-CTX-M-15 gene in Lebanese isolates of extended-spectrum-β-lactamase-producingShigella sonnei

The emergence in Shigella species of extended-spectrum beta-lactamases (ESBL) that impart resistance to third-generation cephalosporins is a growing concern world-wide. So far, however, ESBL-producing Shigella have only been reported seven times, albeit from seven different countries. In Lebanon, three ESBL-producing clinical isolates of S. sonnei were recovered from 30 cases of shigellosis diagnosed between July 2004 and October 2005. All three were found to be resistant to amoxycillin, cefotaxime, ceftazidime, aztreonam, trimethoprim/sulphamethoxazole, gentamicin, and kanamycin. Each harboured the bla-CTX-M gene, and the results of sequence analysis indicated this to be of the bla-CTX-M-15 type and encoded on a 70-kb plasmid, flanked by an insertion element (ISEcp1). The bla-TEM-1 gene was also detected on the chromosomes of two of the ESBL-producing isolates. Class-2 integrons containing dhfr1, aadA1 and sat1 genes were detected on the chromosomes of all three isolates but not on the plasmids. Fluoroquinolone-modifying factors [QnrA, QnrB, QnrS or AAC(6')-Ib-cr] were not detected. The results of RAPD analysis, combined with data on antimicrobial susceptibility, indicated that each isolate was unique. In conclusion, the emergence of ESBL-producing isolates of S. sonnei has been demonstrated for the first time in Lebanon. The resistance of these isolates to third-generation cephalosporins was mediated by the CTX-M-15 enzyme, which was plasmid-encoded.

First detection of oxacillinase-mediated resistance to carbapenems in Klebsiella pneumoniae from Morocco

The frequency of carbapenem resistance due to class-D beta-lactamases (i.e. oxacillinases) among the world's Enterobacteriaceae is increasing. Recently, in Morocco, two isolates of carbapenem-resistant Klebsiella pneumoniae were recovered from the same patient, one harbouring plasmid-encoded bla-(OXA-48) and the other the bla-(OXA-1) gene. This represents the first evidence of bla(OXA-48)-mediated carbapenem-resistance in Enterobacteriaceae in Morocco.

Molecular characterisation of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. isolates at a tertiary-care centre in Lebanon

The prevalence of bla CTX-M, bla TEM and bla SHV genes among extended-spectrum beta-lactamase (ESBL)-producing clinical isolates of Escherichia coli (n = 50) and Klebsiella spp. (n = 50) from Lebanon was 96%, 57% and 67%, and 40%, 82% and 84%, respectively. Genotyping revealed that the clonal diversity was unrelated to the presence of bla genes. Sequence analysis of 16 selected isolates identified the bla CTX-M-15, bla TEM-1, bla OXA-1 and six bla SHV genes, as well as the gene encoding the quinolone-modifying enzyme AAC(6')-Ib-cr. The genes encoding CTX-M-15 and AAC(6')-Ib-cr were carried on a 90-kb plasmid of the pC15-1a or pCTX-15 type, which transferred both ESBL production and quinolone resistance from donors to transconjugants.

Fatal brain infection caused by Aspergillus glaucus in an immunocompetent patient identified by sequencing of the ribosomal 18S–28S internal transcribed spacer

Cerebral aspergillosis has rarely been reported in immunocompetent patients. We herein describe a unique case of cerebral aspergillosis in a healthy adult that led to his death despite aggressive antifungal therapy. Sequencing of ribosomal 18S-28S internal transcribed spacer identified the organism as Eurotium herbariorum, the teleomorph of Aspergillus glaucus.

Seroprevalence of toxocariasis in Lebanon: a pilot study

Toxocariasis is a common helminthic infection that has a worldwide distribution. However, data from Lebanon about the prevalence of this infection are non-existent. We conducted a Toxocara seroprevalence study with 150 subjects attending the outpatient clinics at the American University of Beirut Medical Center between May and June 2004. Serum specimens were tested for anti-Toxocara antibodies by enzyme-linked immunosorbent assay and confirmed by Western blot. Multivariate analysis was performed to identify risk factors for infection. The seroprevalence rate of toxocariasis was 19%. Male gender and below high school education were significantly associated with a positive serological test (odds ratios = 3.1 and 2.8, respectively). Higher numbers of persons in the household, and low family income during childhood, were significant on bivariate analysis only. Toxocariasis is common in Lebanon. A large population-based survey is needed to confirm these results.

Nationwide study of drug resistance among acid-fast bacilli positive pulmonary tuberculosis cases in Lebanon

OBJECTIVE

To assess the prevalence of drug resistance among smear-positive sputum specimens from pulmonary tuberculosis (TB) cases in Lebanon.

DESIGN

Between July 2002 and April 2004, 224 newly diagnosed TB cases and 21 previously treated TB cases were collected nationwide. Mycobacterium tuberculosis isolates were tested against isoniazid (INH), rifampicin (RMP), streptomycin (SM) and ethambutol (EMB) using the BACTEC-TB system.

RESULTS

M. tuberculosis and non-tuberculous mycobacteria (NTM) isolates were recovered from 190 and 15 new cases, respectively, and from 16 and 1 previously treated cases, respectively. Overall drug resistance among new TB vs. previously treated TB cases was 19.5% and 75%, and for single drugs it was INH (12% vs. 63%), RMP (3% vs. 56%), SM (12% vs. 44%) and EMB (3% vs. 44%). The overall rate of multidrug resistance (MDR) was 5.8% (1% vs. 62.5%). The male:female ratio was 1.3:1; most were young adults.

CONCLUSION

Relatively moderate single drug resistance and very low MDR rates were found among new TB cases, while among previously treated TB cases very high resistance and MDR resistance rates were detected. Such findings underline the need for ongoing stringent control measures to curb the spread of M. tuberculosis and its deleterious effects.

Brucella infection in total hip replacement: case report and review of the literature

A 47-y-old female underwent revision of a left total hip replacement because of loose prosthesis. Routine intraoperative culture of the hip site grew Brucella sp. The patient was treated with a combination of vibramycin and rifampicin for 5 months. At 4-y follow-up, her condition is good. Though prosthetic infection with Brucella spp. is an extremly rare condition (only 1 case each of femur and hip, and 3 cases of knee had been previously reported in the English literature), brucella infection of prosthetic joints should be considered in brucella endemic areas.

Campylobacter jejuni: unusual cause of cholecystitis with lithiasis. Case report and literature review

A 51-year-old man presented with acute cholecystitis and the routine intraoperative culture of the bile grew Campylobacter jejuni. The patient was cured by laparoscopic cholecystectomy without specific antimicrobial treatment. Cholecystitis owing to Campylobacter spp. could be missed because a culture for Campylobacter is not routinely requested nor is it cost effective to look for it in bile or gallbladder specimens. Moreover, the fastidious nature of these bacteria dictates against their recovery in routine culture. Because this is a rare infection at this site, a review of the literature on this infection is included.

Prevalence of S315T mutation within the katG gene in isoniazid-resistant clinical Mycobacterium tuberculosis isolates from Dubai and Beirut

OBJECTIVE

To determine the prevalence of S315T mutation within the katG gene that confers clinically significant resistance to isoniazid in isoniazid-resistant Mycobacterium tuberculosis isolates recovered from tuberculosis patients in Dubai and Beirut.

METHOD

A total of 28 and 17 isoniazid-resistant and seven and six susceptible clinical M. tuberculosis isolates from Dubai and Beirut, respectively, were tested. The presence of S315T mutation in the katG gene was detected by amplification of the DNA region around codon 315 by polymerase chain reaction followed by restriction digestion with Msp I to generate restriction fragment length polymorphism. The genotyping of the isolates carrying S315T mutation was carried out by touchdown double-repetitive-element PCR (DRE-PCR).

RESULTS

The mutation S315T was detected in 18 (64%) of 28 isoniazid-resistant isolates from Dubai and in six (35%) of 17 resistant strains from Beirut. None of the susceptible strains contained this mutation. The genotyping studies showed that the majority of the isolates carrying the S315T mutation exhibited unique DNA banding patterns.

CONCLUSION

The data show a varying prevalence of S315T mutation within the katG gene in M. tuberculosis strains isolated from the two geographical locations, Dubai and Beirut.

Ultrashort regimen of lansoprazole-amoxicillin-azithromycin for eradicating Helicobacter pylori

The efficacy and safety of two ultrashort azithromycin-containing regimens for Helicobacter pylori infection were studied. Patients positive for H. pylori infection were assigned to receive either a three-day drug regimen (group A) or a five-day regimen (group B). In both groups, patients received lansoprazole 30 mg p.o. twice daily on day 1 and, on days 2 and 3, lansoprazole 30 mg p.o. twice daily, amoxicillin 1 g (of anhydrous amoxicillin) p.o. twice daily, and azithromycin 500 mg (of anhydrous azithromycin) p.o. twice daily. Group B patients received lansoprazole 30 mg p.o. twice daily and amoxicillin 1 g p.o. twice daily for two additional days. Gastric biopsy specimens were subjected to culture and susceptibility testing. A minimum of four weeks after the completion of therapy, the patients underwent a 14C-urea breath test to determine whether H. pylori had been eradicated. A total of 28 patients were enrolled (15 in group A and 13 in group B). Treatment was well tolerated. H. pylori was eradicated in 4 (36%) of 11 patients in group A and 2 (22%) of 9 group B patients (26.6% and 15.4%, respectively, in intention-to-treat analysis). None of the isolates of H. pylori showed resistance to amoxicillin or clarithromycin. Regimens consisting of lansoprazole plus two or four days of azithromycin and amoxicillin therapy eradicated H. pylori in 36% and 22% of patients, respectively.

Campylobacter fetus pericarditis in a patient with beta-thalassemia: case report and review of the literature

A case of pericardial effusion due to Campylobacter fetus in a patient with thalassemia is presented. The patient failed to respond to ceftriaxone and clarithromycin despite in vitro susceptibility, but improved after pericardiectomy and ampicillin. Pericarditis due to C. fetus has rarely been reported. A high index of suspicion is essential to recognise this organism, because of its special microbiological characteristics.

Prevalence of hepatitis B infection markers in Lebanese children: the need for an expanded programme on immunization

This multi-centre, cross-sectional study was designed to reveal the present status of hepatitis B infection markers among Lebanese children, and provide recommendations regarding childhood immunization policies. A total of 841 children, aged between 6 months and 6.5 years, were enrolled from Lebanon's five districts. Their sera were tested for hepatitis B surface antigen and hepatitis B core IgG. The overall prevalence of hepatitis B virus infection markers was 0.8% with increasing age-specific rates from 0% at 6 months to 1.3 % at > 5 years. There was no statistically significant association between the presence of hepatitis B markers and family characteristics or risk factors for infection. The highest prevalence rates were among children from Beirut suburbs (2.9 %) and South Lebanon (1.6%). The risk of horizontal transmission of hepatitis B to uninfected children increased substantially after the age of 2 years. An expanded programme on immunization that integrates hepatitisB vaccine during the first year of life is needed.

Antimicrobial resistance of Enterococci in Lebanon

There is little information on the types of Enterococcus spp and their antibiotic resistance patterns in Lebanon. One hundred and fifty-three consecutive clinical enterococcal isolates collected between 1998 and 1999 were tested against 11 antimicrobial agents using disk diffusion and the Etest. The isolates were identified by conventional methods and API-Strep and were found to consist of Enterococcus faecalis (72.5%), Enterococcus faecium (22.9%), Enterococcus avium (3.2%) and Enterococcus gallinarum (1.3%). The percent of resistant strains of E. faecalis and E. faecium respectively were, ampicillin 0.9 and 14%, erythromycin 59% and 40%, tetracycline 72% and 34%, chloramphenicol 32 and 11%, rifampin 36% and 57%, ciprofloxacin, 23% and 34%, norfloxacin 22 and 8%. High level aminoglycoside (HLA) resistance was found in 19% E. faecalis and 9% E. faecium for gentamicin and 36% and 26% for streptomycin. Excellent correlation was observed between the high level disk tests and the Etest in the detection of HLA resistance but not with the regular disks. None of the isolates showed resistance to vancomycin or teicoplanin except for one E. gallinarum isolate which showed intermediate resistance (MIC 16 mg/l) to vancomycin. These variable antimicrobial rates of resistance suggest a surveillance programme for antimicrobial resistance in this country would be helpful to help control infection, guide empirical antibiotic therapy and implement a policy of antibiotic usage.

Susceptibility of bacterial isolates to cefepime in comparison to other broad spectrum antimicrobial agents at a tertiary care center in Lebanon

Newly introduced antimicrobial agents have to be evaluated to establish their current activity and susceptibility data base against microorganisms for future comparison. Cefepime is a fourth generation cephalosporin that was recently introduced in Lebanon but no background susceptibility data is available for it in this country. We prospectively analyzed the antimicrobial susceptibility pattern of the bacterial isolates from the American University of Beirut Medical Center to a number of broad spectrum antimicrobial agents and compared it to the susceptibility of cefepime. Consecutive clinical bacterial isolates, representing 665 gram-negative and 387 gram-positive were tested: 82 to 100% of the gram-negative isolates were susceptible to cefepime, including most of the extended spectrum beta-lactamase producing Enterobacteriaceae. All the oxacillin susceptible staphylococcus isolates, and the penicillin susceptible Streptococcus spp. as well as 92% of the S. pneumoniae isolates were susceptible. The data shows that currently, cefepime provides a very broad spectrum of activity against gram-positive as well as gram-negative bacterial isolates recovered from clinical specimens.

Characterization of rpoB mutations in rifampin-resistant Mycobacterium tuberculosis isolates from the Middle East

The nature and frequency of mutations in the rpoB gene of rifampin-resistant clinical Mycobacterium tuberculosis isolates vary considerably according to geographical locations. There is no information on the prevalence of specific mutations in clinical M. tuberculosis strains isolated from patients in Middle-Eastern countries. In this study, 13 rifampin-resistant and 6 susceptible clinical M. tuberculosis isolates were tested for identification and characterization of mutations in the rpoB gene by INNO-LiPA Rif. TB kit and DNA sequencing of the PCR amplified target DNA. The kit identified all six susceptible strains as rifampin-sensitive and the DNA sequence of the amplified rpoB gene in the target region matched perfectly with the wild-type sequence. The kit identified 12 resistant isolates as rifampin-resistant with specific detection of mutations in 8 isolates while one of the rifampin-resistant strain was identified as rifampin-susceptible. DNA sequencing confirmed these results and, in addition, led to the specific detection of mutations in 4 rifampin-resistant isolates in which specific base changes within the target region could not be determined by the INNO-LiPA Rif. TB kit. The majority (8 of 13) of resistant isolates involved base changes at codon 531 of the rpoB gene. Mutations at codon position 531 within the rpoB gene have also been reported in majority of rifampin-resistant strains from Greece and St. Petersburg, Russia but not from other geographical locations.

Comparative performance of PCR-based assay versus microscopy and culture for the direct detection of Mycobacterium tuberculosis in clinical respiratory specimens in Lebanon

SETTING

American University of Beirut Medical Center, Lebanon.

OBJECTIVE

To assess the performance of a polymerase chain reaction (PCR) using primers that flank 542 bp within IS6110 in Mycobacterium tuberculosis (TB) vs. microscopy and BACTEC culture, in the diagnosis of tuberculosis.

DESIGN

A total of 82 clinical respiratory pulmonary specimens and 73 samples from BACTEC vials were tested by the three methods.

RESULTS

Of 24 smear-positive culture-positive (SP-CP) and 11 smear-negative culture-positive (SN-CP) TB specimens, PCR detected 83% and 64%, respectively. Among 17 specimens yielding mycobacteria other than tuberculosis (MOTT), the PCR was positive in 33% SP-CP and 14% SN-CP specimens. Among the 73 BACTEC vials, PCR was positive in 36 of 38 (95%) yielding culture-positive TB, and in one of 20 (5%) yielding culture positive MOTT. None of the 30 smear-negative culture-negative (SN-CN) clinical specimens and 15 of the CN vials were positive by PCR. The overall sensitivity of PCR was 77% and 95% for TB detection in respiratory specimens and BACTEC vials, respectively, and the specificity was 94% in both.

CONCLUSIONS

Because a substantial number of TB cases are missed, especially in SN-CP specimens, a PCR-based assay utilizing these primers cannot be used reliably, alone, in clinical laboratory diagnosis of mycobacterial respiratory infections.

Current status and changing trends of antimicrobial resistance in Lebanon

Antimicrobial resistance among microorganisms has been on the rise worldwide including Lebanon. Several surveillance programs have been initiated to monitor the patterns of resistance due to the deleterious consequences on patients management. Thus, knowledge about the local antimicrobial resistance patterns is essential for epidemiologic aspects as well as clinical practice. In this context, the current status and changing trends of antimicrobial resistance in Lebanon are addressed covering the most relevant bacterial, mycobacterial and fungal pathogens.

Available laboratory tests to guide antimicrobial therapy

Physicians are encountering more difficulties in treating and managing patients with infectious diseases due to the continued emergence of single and multi-drug resistant organisms. This emphasizes the need of laboratory tests that are of help in predicting or monitoring response to therapy. Several conventional, special, automated and molecular antimicrobial susceptibility tests are available including the disk diffusion test, determination of the minimal inhibitory concentration, the E test, serum bactericidal titers, and determination of antimicrobial levels in blood. This article addresses these and other antimicrobial tests to update and enlighten the physicians in selecting the most relevant test(s) that will help guiding the therapy of infections caused by different bacterial etiologic agents.

Comparative study of antituberculous drug resistance among Mycobacterium tuberculosis isolates recovered at the American University of Beirut Medical Center: 1996-1998 vs 1994-1995

PURPOSE

To study the overall current prevalence of antituberculous drug resistance among M. tuberculosis isolates recovered at the American University of Beirut Medical Center (AUBMC) between 1996-1998 in comparison to those reported on isolates recovered in 1994-1995.

MATERIALS AND METHODS

Seventy-four consecutive M. tuberculosis isolates recovered from the same number of newly diagnosed cases of tuberculosis (TB), between January 1996 and December 1998 (referred to as 1998), were tested against isoniazid (INH), rifampicin (RIF), streptomycin (STM) and ethambutol (ETH), using the BACTEC-TB susceptibility procedure and system. The results were compared to those reported on the isolates recovered in 1994-1995 (referred to as 1995).

RESULTS

A comparison between the results obtained in 1998 vs 1995 showed the following, respectively: The male to female ratio was 3.1:1 vs 2:1 and the mean ages were almost similar in males, 33.4 vs 34.1 years but were slightly higher in females 38.2 vs 32.7 years. Children (< or = 15 yrs) represented 10.8% vs 8.3% of the study population. The prevalence of resistance, to one or more drugs, was almost the same, 24% vs 26% but the overall percentages of single drug resistance were generally higher in 1998 vs 1995 against all the tested drugs except INH: INH (20.2% vs 23.9%), RIF (16.2% vs 12.5%), STM (13.5% vs 7.3%) and ETH (8.1% vs 3%). Among the resistant isolates, the profiles of resistance indicated decrease in resistance to one and two drugs, 6.7% vs 11.5% and 5.4% vs 10.4%, respectively, but showed increase in resistance to three and four drugs, 8.1% vs 2.1% and 4% vs 2.1%, respectively. Increase in resistance to two or more drugs was also observed, 17.6% vs 14.6%, and the prevalence of multidrug resistance, defined as resistance to at least both INH and RIF, was also increased, 14.7% vs 11.4%.

CONCLUSIONS

This study shows a high prevalence and persistence of TB drug resistance tested in our Medical Center in Lebanon. In addition, the shift in the increase of resistance from one and two drugs to three and four drugs are very ominous and should be considered when treating patients in this country. Moreover, such information calls for scrutinizing the existing local TB control programs as part of the global efforts to minimize the incidence of this highly morbid infectious disease.

Detection of antibodies to Brucella cytoplasmic proteins in the cerebrospinal fluid of patients with neurobrucellosis

The diagnosis of human neurobrucellosis usually relies on the detection of antibodies to Brucella lipopolysaccharide (LPS) in cerebrospinal fluid (CSF) by agglutination tests or enzyme-linked immunosorbent assay (ELISA). Here we describe the detection of immunoglobulin G (IgG) to cytoplasmic proteins (CP) of Brucella spp. by ELISA and Western blotting in seven CSF samples from five patients with neurobrucellosis. While IgG to CP (titers of 200 to 12, 800) and IgG to LPS (800 to 6,400) were found in the CSF of these patients, these antibodies were not detected in CSF samples from two patients who had systemic brucellosis without neurological involvement. The latter, however, had serum IgG and IgM to both LPS and CP. No reactivity to these antigens was found in CSF samples from 14 and 20 patients suffering from nonbrucellar meningitis and noninfectious diseases, respectively. These findings suggest that, in addition to its usefulness in the serological diagnosis of human systemic brucellosis, the ELISA with CP antigen can be used for the specific diagnosis of human neurobrucellosis.

Viral supraglottitis in an adult: a case presentation and literature update

Viral epiglottitis (supraglottitis) is a rare entity but its presentation can mimic that of bacterial epiglottis. Regardless of the causative agent, supraglottitis is a serious disease mostly affecting children and rarely seen in adults. Early suspicion and proper evaluation are mandatory to prevent a life-threatening crisis. In both children and adults the infectious aetiology in supraglottitis is predominantly bacterial while viruses are rare, especially in adults. We describe a case of supraglottitis in an adult in which the symptoms were insidious and blood indices suggested a bacterial aetiology. However, laryngoscopic examination revealed an ulcer over the left aryepiglottic fold and serology was positive for Herpes simplex virus (HSV) IgM. Because supraglottitis due to HSV is a rare entity with few reported cases in the literature, this case is presented to highlight the viral involvement in this disease and its management.

Drug-resistant Streptococcus pneumoniae in the Lebanon: implications for presumptive therapy

A total of 50 consecutive clinical isolates of Streptococcus pneumoniae, collected between 1996 and 1998, were tested against six antimicrobial agents using the E-test. The percentages of fully resistant (R) and intermediately-R strains, respectively, were: benzyl penicillin 18 and 38%, amoxycillin-clavulanate 6 and 12%, cefuroxime 22 and 16%, ceftriaxone 2 and 16%, and clarithromycin 10%. Fully and or intermediately multidrug-resistance (two or more drugs) was seen in 44% of the isolates, 18% being fully resistant. The MIC breakpoint for cefaclor is not defined by the National Committee for Clinical Laboratory Standards (NCCLS) but MICs showed that: 76% of the isolates had an MIC of < or = 8 mg/l, 4% had an MIC of 16 mg/l and 20% had an MIC of > or = 32 mg/l. There was agreement between the E-test Pen MIC results and the 1 microg oxacillin (oxa) disk diffusion screen test for the 22 susceptible and the nine fully R strains but not for the 19 strains with Pen MICs between 0.1 and 1 mg/l; this shows the importance of MIC determination in such isolates. Penicillin and multiply antibiotic-resistant pneumococci are spreading in Lebanon, emphasizing the necessity to reconsider current treatment regimens in this country.

Human brucellosis: a classical infectious disease with persistent diagnostic challenges

Although brucellosis and its means of transmission were discovered over 100 years ago, the disease remains a world-wide problem, predominantly so in developing countries. Brucellosis has been an emerging disease since the discovery of B. melitensis by Bruce in 1887. The diagnosis of brucellosis can be challenging since its presentation can affect any body organ and system and can overlap that of a wide spectrum of infectious and non-infectious diseases. Routine biochemical and hematological laboratory tests also overlap with those of many other diseases. Thus, brucella-specific tests are the most helpful in the diagnosis. Tests ranging from culture to serodiagnostic tests such as slide or tube agglutination and its indirect Coombs extension, enzyme-linked immunosorbent assay, and indirect fluorescent assays, to the recent molecular techniques such as polymerase chain reaction are available. Knowledge about the advantages, disadvantages, and limitations of these tests are essential for the proper interpretation of their results, in relation to the history and clinical presentation of the individual being investigated. This update article addresses these and other issues related to this classical infectious disease that remains a diagnostic challenge, especially to the unaware.

Discrepancies between mecA PCR and conventional tests used for detection of methicillin resistant Staphylococcus aureus

Conventional and molecular techniques are being used in the detection of methicillin resistance in Staphylococcus aureus but they do not always show concordant results. In this study, a mecA PCR-based amplification was compared with the 1 microg oxacillin disk diffusion test and the Epsilometer test (E-test) for detection of MICs. Among 31 isolates initially characterized as MRSA by the disk diffusion test, mecA was detected in only 13 (42%) isolates. The E-test showed a wide range of oxacillin MICs (0.5 - > 256 microg/ml) among these 31 MRSA isolates: seven isolates had an MIC of > 256 microg/ml, one had 64 microg/ml, two had 4 microg/ml, two had 3 microg/ml, one had 2.5 microg/ml, nine had 2 microg/ml, three had 1.5 microg/ml, five had 1 microg/ml and one had 0.5 microg/ml. Comparing the mecA PCR results with the E-test oxacillin MIC findings revealed that mecA was detected in seven of eight isolates (87.5%) with an MIC of > or = 64 microg/ml, in three of 14 isolates (21.4%) with an MIC of 2-4 microg/ml and in three of nine isolates (33.3%) with an MIC of < 2 microg/ml. Beta-lactamase production was positive in 28/31 isolates (90.3%). Because of this variation between tests and since several resistance mechanisms are known to mediate methicillin resistance in S. aureus, the reliable detection of MRSA cannot be solely based on detection of mecA gene in S. aureus. At this stage and until new guidelines are introduced by an official body, such as NCCLS, a combination of conventional methods alone or together with a molecular method should be used every time S. aureus is tested for detection of methicillin resistance.

Prevalence, antimicrobial susceptibility and molecular characterization of Campylobacter isolates recovered from humans and poultry in Lebanon

Recovery of Campylobacter was attempted from 281 consecutive non selected out-patients diarrheic stools, 150 individual ceca collected from meat chicken breeder farms and 31 slaughtered marketed chicken obtained from shops in Lebanon. Campylobacter isolates were recovered from 2 (0.7%) human stool specimens, 34 (22.7%) chicken ceca and 3 (9.7%) raw chicken carcasses. Speciation of these isolates revealed 2 C. jejuni from humans diarrheic stools, 16 C. coli, 10 C. jejuni, 3 C. fetus, 2 C. fennelliae (Helicobacter fennelliae, new taxon), 2 C. upsaliensis, 1 C. cryaerophila (Archobacter cryaerophilus, new taxon) from chicken ceca and 2 C. coli and 1 C. fennelliae (H. fennelliae) from raw chicken carcasses. Antimicrobial susceptibility testing of the different isolates against 9 antimicrobial agents was performed using the E-test. Overall, most isolates showed high to moderate susceptibility to gentamicin (97%), amoxicillin/clavulanate (95%), clindamycin (77%), chloramphenicol (77%), and ampicillin (69%). Lower susceptibility were observed against tetracycline (49%), erythromycin (47%), ciprofloxacin (39%), and norfloxacin (36%). This overall susceptibility profile generally applied to C. coli and C. jejuni, as well, although C. coli mostly showed higher susceptibility than C. jejuni. beta-lactamase production was detected in 59% of all the isolates, being higher in C. coli (72%) than C. jejuni (33%). Whole cell protein profile analysis of 18 C. coli and 12 C. jejuni by SDS-PAGE revealed 6 different patterns. In both species, major variations existed in the region between mol wt 45-60 and all protein profiles were dominated by the presence of 5 major bands of mol wt: 61 (doublet), 45, 31 and an approximate 24. Differences in banding patterns within and between both species indicated diversity and heterogeneity of strains. This study shows that despite high prevalence and diversity of strains in chicken, Campylobacter in Lebanon is rare in human diarrheic stools compared to Salmonella (3.2%) and Shigella (1.4%).

Antifungal susceptibility of Candida isolates at the American University of Beirut Medical Center

For the first time from Lebanon, the antifungal susceptibility patterns of 70 consecutive clinical candida isolates (each from one patient) representing 48 C. albicans, 12 C. tropicalis, 6 C. parapsilosis, 2 C. kruseii, and 2 C. (Torulopsis) glabrata were studied against amphotericin B (AP), 5-fluorocytosine (FC), ketoconazole (KE), fluconazole (FL), and itraconazole (IT) using the Epsilometer test (E-test; AB Biodisk, Solna, Sweden). The MIC90 (and MIC range, mg/l) determined, at 24 h incubation, for each antifungal agent against C. albicans were: AP 0.032 (< or = 0.002-0.064), FC 0.75 (0.023-2), KE 0.064 (0.002- > 32), FL 2 (0.064- > 256), and IT 0.19 (0.012-2), against C. tropicalis were: AP 0.016 (< 0.002-0.047), FC 0.125 (0.023-0.19), KE 0.094 (0.012-0.19), FL 2 (0.5-2), and IT 0.5 (0.047-1) and against C. parapsilosis were: AP < 0.002 (< 0.002-0.002), FC 0.047 (0.003-0.5), KE 0.004 (0.002-0.004), FL 0.125 (0.032-0.19), and IT 0.004 (< 0.002-0.004). Based on the NCCLS established MICs breakpoints, resistance was found among C. albicans to FL (MIC > or = 6 mg/l) and IT (MIC > or = 1 mg/l) in 6 and 4%, respectively, and among C. tropicalis to IT in 17% of the isolates. The susceptibility dependent upon dose (S-DD) was noted only to IT (MIC 0.25-0.5 mg/l) among C. albicans (8%) and C. tropicalis (58%). MICs determination at 48 h incubation were higher, showed more resistance rates and more endpoint trailing particularly with the azoles drugs. The small numbers of C. kruseii and C. glabrata preclude providing meaningful results. Thus, this study indicates that the antifungal susceptibility by E-test can be conveniently incorporated and performed in a hospital-based clinical laboratory. Despite the uniform susceptibility to AP and FC, resistance to azoles drugs is encountered in a range of 4-17% among candida isolates in this country.

Brucella-infected ovarian dermoid cyst causing initial treatment failure in a patient with acute brucellosis

A 37-year-old woman was diagnosed with acute brucellosis. Despite appropriate antimicrobial therapy, high fever persisted. A contrast enhanced CT scan of the abdomen and pelvis revealed a left ovarian dermoid cyst. On the first postoperative day after left ovariectomy and right ovarian cystectomy were performed, the patient defervesced abruptly and continued to be completely afebrile. Cultures from bone marrow and dermoid cyst grew Brucella melitensis. The observation of a Brucella-infected ovarian dermoid cyst, which has not been previously reported, illustrates the importance of localized brucellosis as a cause of persistent infection despite appropriate antimicrobial therapy.

Post immunization Hib antigen detection in the CSF of a patient with meningococcal meningitis

We report a case of meningococcal meningitis where the cerebrospinal fluid was negative for Neisseria meningitidis but positive for Haemophilus influenzae type b by rapid antigen detection test. We believe that this was due to prior immunization with Haemophilus influenzae type b vaccine. We recommend caution in interpretation of the rapid antigen detection tests especially in patients who had been vaccinated against organisms screened by these tests.

Drug resistance among Mycobacterium tuberculosis isolates in Lebanon

OBJECTIVE

To determine the prevalence and patterns of drug resistance among Mycobacterium tuberculosis isolates recovered from tuberculosis (TB) cases in Lebanon.

DESIGN

A total of 96 isolates were collected from the same number of TB cases between October 1994 and December 1995. These isolates were obtained from cases with newly diagnosed (81.3%) and previously treated (18.7%) cases of TB, and tested against isoniazid (INH), rifampicin (RIF), streptomycin (STM) and ethambutol (ETH), using the BACTEC-TB susceptibility procedure and system.

RESULTS

The male to female ratio was 2:1 and the mean ages of males and females were almost similar, 34.1 and 32.7 years, respectively. Resistance to one or more drugs was found in 25 of 96 (26%) isolates. The overall percentages of single drug resistance against INH, RIF, STM and ETH were 23.9%, 12.5%, 7.3% and 3.1%, respectively. These percentages were higher, for all drugs, in isolates recovered from previously treated compared to new cases of TB: INH (50% vs 17.9%), RIF (33.3% vs 7.7%), STM (22.2% vs 3.8%) and ETH (11.1% vs 1.3%). Of the 25 resistant isolates, 11 were resistant to one drug only (10 to INH and 1 to STM), 10 were resistant to two drugs (7 to INH and RIF, 2 to INH and STM, 1 to STM and RIF), 2 were resistant to three drugs (1 to INH, RIF and ETH, 1 to INH, RIF and STM) and 2 were resistant to the four tested drugs.

CONCLUSION

These data show that M. tuberculosis isolates in Lebanon have high rates of single and multidrug resistance, and speaks for the need to establish surveillance and monitoring programs in this country as part of the global effort to control TB.

Seroprevalence of brucella antibodies among persons in high-risk occupation in Lebanon

Prevalence of brucella-specific antibodies was measured in 597 persons in high-risk occupations living in 10 regions of Lebanon using the standard agglutination test (SAT), anti-human globulin (Coombs') test (AHGT) and enzyme-linked immunosorbent assay (ELISA) for measuring immunoglobulin G (IgG), IgM and IgA. The study population consisted of butchers (54%), farmers (35%), laboratory technicians (8%), abbatoir workers (2%) and veterinarians (1%), with 82% males and 18% females. The overall seroprevalence based on SAT and AHGT titres of > or = 80 was 1.7% and 15%, respectively, but seroprevalence varied by region from 0-5% in SAT and from 3.4-34% for AHGT. The overall seroprevalence based on ELISA IgG (OD > or = 0.6), IgM (OD > or = 0.6) and IgA (OD > or = 0.3) was 57, 61 and 26%, respectively. The highest seroprevalence was noted in Biqaa (34%), Kisrwan (24%), Shouf (21%), Sidon (16%) and Aley (12%) regions. Nineteen percent of those surveyed reported symptoms that could be associated with brucellosis. We conclude that exposure to brucellosis is high among persons in high-risk occupations from all surveyed regions in Lebanon. Such findings should be used to design control measures especially now that the 17 years of civil strife is over.

Prevalence and etiology of intestinal parasites in Lebanon

As there are no studies done on the prevalence of intestinal parasites in Lebanon since 1967, this study was undertaken to reveal the current patterns of intestinal parasitic infestations in Lebanese patients from two geographic regions: Beirut and Tripoli. Analysis was based on 33,253 stool specimens examined at the American University of Beirut Medical Center (AUH) and 11,611 specimens examined at the Islamic Hospital (IH) in Tripoli over five and three years, respectively. The prevalence of intestinal parasites at AUH and IH were 8.47% and 45.35%, respectively (overall 18%). The prevalence in males vs females was almost the same; being 8.23% vs 8.74%, and 44.67% vs 45.88%, at AUH and IH, respectively. Multiple infections were noted in 8.8% and 3.5% of stool specimens at AUH and IH, respectively. Although 18 different types of parasites were encountered, the most common pathogenic parasites found at AUH vs IH were: Giardia lamblia (20.7% vs 10.5% of parasites found), Entamoeba histolytica (19.41% vs 1.25%), Taenia spp. (6.03% vs 4.08%) and Ascaris lumbricoides (2.09% vs 46.97%). The overall yearly or monthly prevalence of parasites recovered from both hospitals did not show clear seasonal patterns. Compared to developed countries, Lebanon still suffers from a high prevalence and a wide spectrum of intestinal parasites.

Cryptococcal meningitis and confusional psychosis. A case report and literature review

A previously healthy and immuno-competent 22-year-old man presented in confusional psychosis. Cryptococcal meningitis was later found to be the underlying cause as proven by culturing Cryptococcus neoformans serotype A from the cerebrospinal fluid. Combined antifungal therapy with amphotericin B and 5-fluorocytosine resulted in sustained improvement of all mental and physical functions. Cryptococcosis has rarely been reported from the Middle East. This represents the second case from Kuwait.

Hepatitis C virus : prevalence in Lebanese blood donors and brief overview of the disease

Hepatitis C virus (HCV) is recognized as the major cause of non-A, non-B hepatitis. Its prevalence in different patient populations and blood donors has been reported worldwide but not yet from Lebanon. This study was performed to determine the prevalence of HCV antibodies in 536 random Lebanese blood donors using three enzyme immunoassay kits: ETI-AB-HCVK (Sorin, Biomedica, Italy), UBI HCV EIA (Organon Teknika, Netherlands) and ORTHO HCV 2.0 ELISA (Ortho Diagnostic Systems, USA). The latter was also used as an arbitrator test. Though ETI-AB-HCVK and UBI HCV EIA kits gave higher initial positive results (5.8% and 3.7%, respectively) than ORTHO HCV 2.0 ELISA (1.1%), the over all prevalence of HCV antibody in these blood donors was 0.7%. A brief review of the HCV virus, its epidemiology, clinical features and diagnostic aspects is also presented. A similar testing approach was carried out on additional 3643 blood donors. Confirmatory testing based on CHIRON*RIBA*HCV 2.0 strip immunoblot assay (Ortho) revealed that the HCV antibody seroprevalence in random Lebanese blood donors is 0.11% and not 0.7% as found by ELISAs alone.

Antimicrobial susceptibility patterns of bacterial isolates at the American University Medical Center in Lebanon

In Lebanon, knowledge of the prevailing pattern of bacterial resistance to antimicrobial agents has been limited, particularly because of 15 years of civil strife. Thus, the current study was conducted to determine the antimicrobial susceptibility patterns of nonselected bacterial isolates recovered from recent clinical specimens, using the standardized disk agar diffusion technique. A total of 5216 isolates (1443 Gram positive and 3773 Gram negative) were examined. Over 92% of Staphylococcus aureus and coagulase-negative staphylococci (CNS) were resistant to penicillins. Methicillin resistance was more frequently noted among CNS (28%) compared with S. aureus (18%). For the pneumococci, 27% of the isolates were resistant to penicillin G. High but variable rates of multidrug resistance were encountered among Acinetobacter spp., Pseudomonas spp., Serratia spp., Citrobacter spp., and Enterobacter spp. Ampicillin resistance was detected in 65% of Escherichia coli and in 20% of Haemophilus influenzae isolates. Although one resistant Salmonella typhi strain was observed, 17% of other Salmonella spp. and 60% of Shigella spp. proved to be resistant to ampicillin, chloramphenicol, and cotrimoxazole. Among Vibrio cholerae isolates, high resistance to tetracycline (71%) and trimethoprim-sulfamethoxazole (94%) was observed. The overall antimicrobial resistance rates in Lebanon seem to fall between figures reported from the Arabian Gulf countries (higher) and those from medical centers in the United States (lower).

Improved detection of mycobacterial antigens in clinical specimens by combined enzyme-linked immunosorbent assay

Three types of antibodies against cellular and secretory-excretory protein antigens were simultaneously used for the direct detection of mycobacterial antigens in sputum and cerebrospinal fluid (CSF) specimens, using enzyme-linked immunosorbent assay (ELISA). The antibodies consisted of in-house raised and prepared anti-whole-cell, heat-killed, and sonicated Mycobacterium tuberculosis, anti-secretory-excretory protein extract of bacilli Calmette-Guerin (BCG) strain, and commercially available anti-BCG. Sputum specimens comprised 24 smear positive, culture positive, and 47 smear-negative, culture positive (SNCP), from patients with pulmonary tuberculosis, as well as 45 smear-negative, culture-negative (SNCN) control samples. The CSF specimens included 18 SNCPs from patients with tuberculous meningitis and 18 SNCN controls. The sensitivity of the individual tests for sputum and CSF specimens ranged from 70% to 79% and 72% to 89%, respectively, whereas in the combined tests it reached 86%-96% for sputum specimens and 100% for CSF specimens. The specificity of ELISAs for sputum specimens was lower in the combined (73%-87%) than in the individual (87%-98%) tests, whereas for CSF specimens it was 100% in all tests. Thus, the combined ELISA approach for mycobacterial antigen detection provides a rapid and reliable laboratory adjunct in the diagnosis of patients with tuberculosis.

Brucella arthritis: a study of 96 cases in Kuwait

Of 400 patients with brucellosis, 104 (26%) had arthritis, of whom 96 could be followed up. The systemic disease in the 96 patients was acute in 54 (56%), subacute in 24 (25%), and chronic in 18 (19%). The main presenting symptoms were joint pain, fever, sweating, and easy fatigability. The joints most commonly affected were the sacroiliac joint (26%) and knee (25%) followed by hip (18%) and spine (8%). There was no particular pattern of joint affection in relation to age. Joint effusion occurred in 32/104 (30%) of cases, predominantly (94%) in the acute group. Culture of synovial fluid was negative in all, and analysis of synovial fluid for cellular profile, glucose, and protein content was not particularly helpful in diagnosis. Plain radiographs did not show major pathological changes. Among the laboratory tests, including haematological and liver function tests, the brucella enzyme linked immunosorbent assay (ELISA) was the most reliable in the diagnosis of disease, using serum and synovial fluid specimens. Treatment with a combination of streptomycin plus tetracyclines or rifampicin resulted in an excellent cure rate and resolution of arthritis without sequelae or mortality. Thus brucellosis should be considered in the differential diagnosis of arthritis, especially in areas in which the disease is endemic.