Atef M. Shibl

High Prevalence of Antimicrobial Resistance among Clinical Streptococcus pneumoniae Isolates in Asia (an ANSORP Study)

ABSTRACT A total of 685 clinical Streptococcus pneumoniae isolates from patients with pneumococcal diseases were collected from 14 centers in 11 Asian countries from January 2000 to June 2001. The in vitro susceptibilities of the isolates to 14 antimicrobial agents were determined by the broth microdilution test. Among the isolates tested, 483 (52.4%) were not susceptible to penicillin, 23% were intermediate, and 29.4% were penicillin resistant (MICs ≥ 2 mg/liter). Isolates from Vietnam showed the highest prevalence of penicillin resistance (71.4%), followed by those from Korea (54.8%), Hong Kong (43.2%), and Taiwan (38.6%). The penicillin MICs at which 90% of isolates are inhibited (MIC90s) were 4 mg/liter among isolates from Vietnam, Hong Kong, Korea, and Taiwan. The prevalence of erythromycin resistance was also very high in Vietnam (92.1%), Taiwan (86%), Korea (80.6%), Hong Kong (76.8%), and China (73.9%). The MIC90s of erythromycin were >32 mg/liter among isolates from Korea, Vietnam, China, Taiwan, Singapore, Malaysia, and Hong Kong. Isolates from Hong Kong showed the highest rate of ciprofloxacin resistance (11.8%), followed by isolates from Sri Lanka (9.5%), the Philippines (9.1%), and Korea (6.5%). Multilocus sequence typing showed that the spread of the Taiwan19F clone and the Spain23F clone could be one of the major reasons for the rapid increases in antimicrobial resistance among S. pneumoniae isolates in Asia. Data from the multinational surveillance study clearly documented distinctive increases in the prevalence rates and the levels of antimicrobial resistance among S. pneumoniae isolates in many Asian countries, which are among the highest in the world published to date.

Changing Trends in Antimicrobial Resistance and Serotypes of Streptococcus pneumoniae Isolates in Asian Countries: an Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study

ABSTRACT Antimicrobial resistance in Streptococcus pneumoniae remains a serious concern worldwide, particularly in Asian countries, despite the introduction of heptavalent pneumococcal conjugate vaccine (PCV7). The Asian Network for Surveillance of Resistant Pathogens (ANSORP) performed a prospective surveillance study of 2,184 S. pneumoniae isolates collected from patients with pneumococcal infections from 60 hospitals in 11 Asian countries from 2008 to 2009. Among nonmeningeal isolates, the prevalence rate of penicillin-nonsusceptible pneumococci (MIC, ≥4 μg/ml) was 4.6% and penicillin resistance (MIC, ≥8 μg/ml) was extremely rare (0.7%). Resistance to erythromycin was very prevalent in the region (72.7%); the highest rates were in China (96.4%), Taiwan (84.9%), and Vietnam (80.7%). Multidrug resistance (MDR) was observed in 59.3% of isolates from Asian countries. Major serotypes were 19F (23.5%), 23F (10.0%), 19A (8.2%), 14 (7.3%), and 6B (7.3%). Overall, 52.5% of isolates showed PCV7 serotypes, ranging from 16.1% in Philippines to 75.1% in Vietnam. Serotypes 19A (8.2%), 3 (6.2%), and 6A (4.2%) were the most prominent non-PCV7 serotypes in the Asian region. Among isolates with serotype 19A, 86.0% and 79.8% showed erythromycin resistance and MDR, respectively. The most remarkable findings about the epidemiology of S. pneumoniae in Asian countries after the introduction of PCV7 were the high prevalence of macrolide resistance and MDR and distinctive increases in serotype 19A.

Spread, Circulation, and Evolution of the Middle East Respiratory Syndrome Coronavirus

ABSTRACT The Middle East respiratory syndrome coronavirus (MERS-CoV) was first documented in the Kingdom of Saudi Arabia (KSA) in 2012 and, to date, has been identified in 180 cases with 43% mortality. In this study, we have determined the MERS-CoV evolutionary rate, documented genetic variants of the virus and their distribution throughout the Arabian peninsula, and identified the genome positions under positive selection, important features for monitoring adaptation of MERS-CoV to human transmission and for identifying the source of infections. Respiratory samples from confirmed KSA MERS cases from May to September 2013 were subjected to whole-genome deep sequencing, and 32 complete or partial sequences (20 were ≥99% complete, 7 were 50 to 94% complete, and 5 were 27 to 50% complete) were obtained, bringing the total available MERS-CoV genomic sequences to 65. An evolutionary rate of 1.12 × 10−3 substitutions per site per year (95% credible interval [95% CI], 8.76 × 10−4; 1.37 × 10−3) was estimated, bringing the time to most recent common ancestor to March 2012 (95% CI, December 2011; June 2012). Only one MERS-CoV codon, spike 1020, located in a domain required for cell entry, is under strong positive selection. Four KSA MERS-CoV phylogenetic clades were found, with 3 clades apparently no longer contributing to current cases. The size of the population infected with MERS-CoV showed a gradual increase to June 2013, followed by a decline, possibly due to increased surveillance and infection control measures combined with a basic reproduction number (R0) for the virus that is less than 1. IMPORTANCE MERS-CoV adaptation toward higher rates of sustained human-to-human transmission appears not to have occurred yet. While MERS-CoV transmission currently appears weak, careful monitoring of changes in MERS-CoV genomes and of the MERS epidemic should be maintained. The observation of phylogenetically related MERS-CoV in geographically diverse locations must be taken into account in efforts to identify the animal source and transmission of the virus. MERS-CoV adaptation toward higher rates of sustained human-to-human transmission appears not to have occurred yet. While MERS-CoV transmission currently appears weak, careful monitoring of changes in MERS-CoV genomes and of the MERS epidemic should be maintained. The observation of phylogenetically related MERS-CoV in geographically diverse locations must be taken into account in efforts to identify the animal source and transmission of the virus.

Carriage of Antibiotic-Resistant Pneumococci among Asian Children: A Multinational Surveillance by the Asian Network for Surveillance of Resistant Pathogens (ANSORP)

To investigate the nasal carriage of antibiotic-resistant pneumococci by children, anterior nasal swabs were done for 4963 children <5 years old in 11 countries in Asia and the Middle East. In total, 1105 pneumococci isolates (carriage rate, 22.3%) were collected, 35.8% of which were found to be nonsusceptible to penicillin. Prevalence of penicillin nonsusceptibility was highest in Taiwan (91.3%), followed by Korea (85.8%), Sri Lanka (76.5%), and Vietnam (70.4%). Penicillin resistance was related to residence in urban areas, enrollment in day care, and a history of otitis media. The most common serogroups were 6 (21.5%), 23 (16.5%), and 19 (15.7%). The most common clone, as assessed by pulsed-field gel electrophoresis, was identical to the Spanish 23F clone and to strains of invasive isolates from adult patients. Data in this study documented the high rate of penicillin or multidrug resistance among isolates of pneumococci carried nasally in children in Asia and the Middle East and showed that this is due to the spread of a few predominant clones in the region.

Pharmacokinetics of 125I-labelled antivenin to the venom from the scorpion Androctonus amoreuxi

Abstract An antivenin for A. amoreuxi venom was prepared by hyperimmunizing rabbits. The globulin fraction was separated and purified and the immunogloblin fraction (chiefly IgG) separated, purified and radioiodinated. Using the immunodifussion technique, seven prominent and two faint precipitin bands were found with both the crude antivenin and the globulin fraction and four prominent and one faint precipitin bands with the immunoglobulin fraction, when tested against the venom. Ten milligrams of the immunoglobulin fraction (Ig) protected the mice from the lethal action of a dose of the venom equal to 5 times the ld 50 . The corresponding values for the globulin fraction and the crude antivenin were 70 mg and 4 ml, respectively. The pharmacokinetic profile of the labelled Ig was determined following rapid i.v. injection into rabbits. The data obtained showed an excellent fit to a triexponential equation of the form: C p,t = P e − πt + A e − αt ;+ B e − βt ; where C p,t is the antivenin concentration in the blood at time t , π, α and β are hybrid rate constants and P , A and B are the corresponding zero time intercepts. This equation represents a pharmacokinetic model consisting of a central compartment from which distribution to a rapidly equilibrating “shallow” compartment and a slowly equilibrating “deep” compartment takes place, with elimination taking place from the central compartment. The apparent half-lives for the early declining phases were 1.06 and 9.63 hr for the rapidly and slowly equilibrating compartments, respectively. The overall elimination half life was 43.3 hr. The ineffectiveness of serotherapy with scorpion antiven injected several hours after scorpion sting might be due to differences in distribution half lives.

The emergence of OXA-48- and NDM-1-positive Klebsiella pneumoniae in Riyadh, Saudi Arabia

OBJECTIVES To investigate the emergence of NDM-, OXA-48-, and VIM-producing Klebsiella pneumoniae in Saudi Arabia. METHODS From June to December 2011, we obtained K. pneumoniae isolates with reduced sensitivity to carbapenem identified in Riyadh, Saudi Arabia. Only non-duplicate clinical and surveillance isolates obtained from inpatients were included. PCR amplification was carried out for the detection of extended-spectrum beta-lactamase genes (blaCTX-M, blaTEM, blaSHV) and carbapenemase genes (blaKPC, blaVIM, blaIMP, blaNDM, and blaOXA-48). Susceptibility to imipenem, meropenem, amikacin, gentamicin, trimethoprim-sulfamethoxazole, and colistin was determined. RESULTS Of the 60K. pneumoniae isolates studied, 45 were from patients in the intensive care unit. Forty-seven isolates harbored blaOXA-48, 12 were positive for blaNDM, and one for blaVIM. No isolate harbored a combination of these resistance genes. No isolate harbored blaKPC or blaIMP. All 37 blaCTX-M-positive isolates belonged to CTX-M group 1, and 29 were positive for a combination of blaCTX-M and blaOXA-48. blaTEM and blaSHV genes were found in 17 and 39 isolates, respectively. All isolates were imipenem- and meropenem-resistant, with a high rate of co-resistance to the other antibiotics. Three blaOXA-48-positive isolates with colistin resistance were detected. CONCLUSION Multidrug-resistant K. pneumoniae isolates harboring blaOXA-48, blaNDM, and colistin resistance are emerging in Saudi Arabia.

Molecular characterization of carbapenem-insensitive Acinetobacter baumannii in Egypt

OBJECTIVES This study investigated the prevalence of diverse Ambler class β-lactamase-encoding genes in 40 carbapenem-insensitive Acinetobacter baumannii isolates collected from two hospitals in Egypt during the period January-March 2012. METHODS The resistance levels to different groups of antimicrobial agents were determined. PCR was used to detect the different Ambler class β-lactamases encoding the following genes: blaTEM, blaSHV, blaCTX-M, blaVEB, blaPER, blaGES, blaVIM, blaIMP, blaSIM, blaSPM, blaGIM, blaNDM, blaADC, blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58. ISAba1 and int1 were detected by PCR. RESULTS The isolates were 100% resistant to amoxicillin-clavulanate, aztreonam, cefepime, cefotaxime, and ceftazidime. Of the isolates, 5% were resistant to colistin, 45% to amikacin, 70% to imipenem, and 85% to ciprofloxacin. The blaADC- and blaOXA-51-like genes were detected in the entire collection. The prevalences of blaOXA-23, blaOXA-24, and blaOXA-58 were 50%, 7.5%, and 5%, respectively. However, the prevalences of blaTEM-, blaPER-, and blaGES-like genes were 87.5%, 55%, and 27.5%, respectively. SHV, CTX-M, VEB, KPC, and MBL encoding genes were not detected. The ISAba1 was found upstream to blaOXA-51, blaOXA-23, and blaADC in 85%, 80%, and 50%, respectively. Of note, 45% (18/40) of the isolates co-produced extended-spectrum β-lactamases (PER and GES) and carbapenemases (OXA-23 and OXA-58). CONCLUSIONS The blaADC-, blaTEM-, blaPER-, blaOXA-23-, and blaGES-like genes were found to be the most prevalent types of β-lactamase-encoding gene in A. baumannii collected from Egypt. A high level of carbapenem resistance is mediated by blaOXA-23, blaOXA-24, and blaOXA-58 (minimum inhibitory concentration (MIC) 32 to >256μg/ml), and a low level of carbapenem resistance is mediated by blaGES (MIC 4-16μg/ml) and by up-regulation of ISAba1-OXA-51 (MIC 1-4μg/ml). Class B MBL was not identified to play a role in carbapenem resistance in A. baumannii isolates from Egypt.

Prevalence and Genetic Characteristics of TEM, SHV, and CTX-M in Clinical Klebsiella pneumoniae Isolates from Saudi Arabia

The prevalence and genetic basis of extended-spectrum beta-lactamases (ESBLs) in Klebsiella pneumoniae remains unclear in Saudi Arabia. Therefore, this study was devoted to determine the prevalence and characterize ESBL-producing K. pneumoniae in Al-Qassim area, Saudi Arabia. A total of 430 isolates of K. pneumoniae isolated from clinical samples were collected over 6 months from January to June 2008. These isolates were screened for the presence of ESBLs by double-disk synergy test and re-evaluated by E-test ESBL method. Minimum inhibitory concentrations of 15 antibiotics against ESBL-positive strains were determined by E-test strips. The β-lactamases involved were characterized by polymerase chain reaction assays and DNA sequencing. Conjugation experiments were done and ISEcp1 elements were tested among CTX-M positive isolates. The prevalence of ESBL was 25.6% (110/430) and all ESBL-positive isolates were sensitive to imipenem and tigecycline; however, the resistance rate to gentamicin, amikacin, and ciprofloxacin was 87.3%, 10%, and 9.1%, respectively. Of these, 89.1% produced SHV, 70.9% produced TEM, and 36.4% were CTX-M-producing strains. The prevalence of ESBL SHV SHV-12 and SHV-5 was of 60% and 18.2%, respectively, and various non-ESBL SHV, including SHV-1 (5.5%), -11 (3.6%), and -85 (1.8%), was detected. However, the prevalence of CTX-M-15 and CTX-M-14 was 34.5% and 1.8%, respectively. ISEcp1 element was detected in 60% of bla(CTX-M-15) genes. All bla(CTX-M) genes were transferable; however, most of bla(SHV-12) and bla(SHV-5) were not transferable. TEM-type ESBLs were not detected in any of the isolates. This is the first description of CTX-M-14, SHV-5, SHV-11, and SHV-85 in Saudi Arabia. We have documented the dominance of K. pneumoniae SHV-12 and highlighted the emergence of CTX-M-15 in Saudi Arabia.

Heparin and heparin-surface-modification reduce Staphylococcus epidermidis adhesion to intraocular lenses

Bacterial adherence to intraocular lenses (IOLs) could be the cause of endophthalmitis following cataract surgery and lens implantation. The majority of cases of postoperative endophthalmitis are caused by microflora that reside on or near the eye of the patient. Staphylococcus epidermidis commonly colonizes the eyelid margin and conjunctiva and is the most common organism causing postoperative endophthalmitis. In this study, the in vitro adherence of S. epidermidis to regular poly-methyl methacrylate (PMMA) IOLs and to heparin-surface-modified (HSM) PMMA IOLs was investigated. The effects of heparin and antibiotics in solution on the adherence of bacteria to regular PMMA IOLs were evaluated. Adhesion of bacterial cells to IOLs was determined by counting the viable cells attached to the lenses. Significantly, fewer S. epidermidis attached to HSM-PMMA IOLs and to regular PMMA IOLs treated with heparin than to PMMA IOLs (p < 0.001). Furthermore, bacteria attached in significantly lower numbers to regular PMMA IOLs treated with heparin than to HSM-PMMA IOLs (p = 0.0031). Antibiotics in solution had no significant effect on bacterial adherence to PMMA IOLs. These data indicate that the use of HSM-PMMA IOLs and treatment of PMMA IOLs with heparin could diminish the incidence of postoperative endophthalmitis and intraocular inflammation associated with IOL implantation.

Epidemiology of invasive pneumococcal disease in the Arabian Peninsula and Egypt.

Invasive pneumococcal disease (IPD) causes considerable morbidity and mortality among children worldwide. This review describes the burden of disease and pneumococcal serotypes/serogroups causing disease in children in the Arabian Peninsula and Egypt identified from a literature search from 1990 to 2007. The incidence of IPD in children aged <or=5 years ranged from 3.4 to 53.5 per 100000. Bacteraemia cases were responsible for 61-100% (children <2 years) of total IPD. Pneumococcal meningitis cases ranged from 3% to 25% (<2 years) and from 7% to 30% (<or=5 years). The most common IPD serotypes/serogroups were 14, 23F, 6B, 19F and 6A (<or=5 years). Circulating serotypes/serogroups causing IPD potentially covered by the 7-valent pneumococcal conjugate vaccine (PCV-7) ranged from 49% to 83% (<2 years) and from 61% to 69% (<or=5 years). Penicillin resistance among invasive isolates ranged from 0% to 78%. Case fatality and morbidity rates for pneumococcal meningitis were 0-22% and 10-62%, respectively. Incidence and morbidity data for meningitis and bacteraemia demonstrate a substantial vaccine-preventable burden of IPD in young children. Standardisation of definitions and development of improved regional surveillance/reporting would enable the region to measure better the impact of prevention strategies for IPD, such as infant-based immunisation programmes.