Rita Dhar

Antibacterial resistance and their genetic location in MRSA isolated in Kuwait hospitals, 1994-2004

BackgroundMethicillin-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.MethodsBetween 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.ResultsThey 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 proportion of the isolates resistant to erythromycin, ciprofloxacin and fusidic acid increased during the study period. In contrast, the proportion of isolates resistant to gentamicin, tetracycline, chloramphenicol and trimethoprim declined. High-level mupirocin resistance increased rapidly from 1996 to 1999 and then declined. They contained plasmids of 1.9, 2.8, 3.0, 4.4, 27 and 38 kilobases. Genetic studies revealed that they carried plasmid-borne resistance to high-level mupirocin resistance (38 kb), chloramphenicol (2.8 – 4.4 kb), erythromycin (2.8–3.0 kb) and cadmium acetate, mercuric chloride, propamidine isethionate and ethidium bromide (27 kb) and chromosomal location for methicillin, the aminoglycosides, tetracycline, fusidic acid, ciprofloxacin and trimethoprim resistance. Thus, the 27 kb plasmids had resistance phenotypes similar to plasmids reported in MRSA isolates in South East Asia.ConclusionThe prevalence of resistance to erythromycin, ciprofloxacin, high-level mupirocin and fusidic acid increased whereas the proportion of isolates resistant to gentamicin, tetracycline, chloramphenicol and trimethoprim declined during the study period. They contained 27-kb plasmids encoding resistance to cadmium acetate, mercuric chloride, propamidine isethionate and ethidium bromide similar to plasmids isolated in MRSA from South East Asia. Molecular typing of these isolates will clarify their relationship to MRSA from South East Asia.

Surveillance of antibacterial resistance in Staphylococcus aureus isolated in Kuwaiti hospitals.

Objective: To investigate the prevalence of antibiotic resistance among Staphylococcus aureus isolated in Kuwaiti hospitals. Materials and Methods:S. aureus were isolated and identified following standard microbiological methods. Antibacterial susceptibility test was performed by disk diffusion and the measurement of minimum inhibitory concentration with E-test strips. Results: A total of 1,846 S. aureus isolates were analyzed from 13 hospitals between 1 March and 30 October 2005. They were isolated from 1,765 (95.6%) inpatients and 81 (4.4%) outpatients. Methicillin resistance was detected in 588 (32.0%) of the isolates. The methicillin-resistant S. aureus (MRSA) consisted of 461 (78%) multiresistant and 127 (22%) nonmultiresistant isolates. The nonmultiresistant MRSA consisted of epidemic MRSA-15 and community-associated MRSA. The community-associated MRSA was detected in all hospitals with MRSA, indicating its establishment in Kuwaiti hospitals. The proportion of isolates resistant to gentamicin, kanamycin, erythromycin, tetracycline, ciprofloxacin, fusidic acid and trimethoprim was higher among MRSA than methicillin-susceptible S. aureus (MSSA) isolates. Twenty-four and 22% of MRSA and MSSA isolates, respectively, expressed reduced susceptibility to vancomycin (minimum inhibitory concentration = 3–4 mg/l). Conclusion: The study revealed the presence of methicillin resistance in 32% of S. aureus isolated in Kuwaiti hospitals and revealed an increase in the number of MRSA and MSSA with reduced susceptibility to vancomycin.

High prevalence and level of resistance to metronidazole, but lack of resistance to other antimicrobials in Helicobacter pylori, isolated from a multiracial population in Kuwait

The primary treatment regimen for Helicobacter pylori infection for Kuwaitis does not contain metronidazole, but that for expatriates does. There is also increasing failure of antimicrobial therapy.

Significance of Atypical Pathogens among Community-Acquired Pneumonia Adult Patients Admitted to Hospital in Kuwait

Objectives: The aim of this study is to determine the microbial etiology and severity of community-acquired pneumonia (CAP) in Kuwait. Subjects and Methods: The severity of consecutive adult CAP cases admitted to 3 hospitals over a 1-year period was classified according to the Pneumonia Outcome Research Team (PORT) severity index. The microbial etiology was determined using standard methods for bacteria and serological tests for atypical and viral pathogens. Results: The study population was 124 of the 135 admissions; 63 female, 61 male; mean age 41.3 ± 18 years. The severity class distribution was: class I 31%, class II 37%, class III 17%, class IV 13%, and class V 2%. Etiological agents were identified from 44 patients (35%), with one pathogen in 31 (25%), two in 9 (7%), and three or more in 4 (3%). The most common pathogens identified were: Mycoplasma pneumoniae in 14 patients (11%), Legionella pneumophila in 10 (8%), Chlamydia pneumoniae in 8 (6%), influenza B virus in 8 (6%), influenza A virus in 5 (4%), Haemophilus influenzae in 4 (3%), Streptococcus pneumoniae in 3 (2%), Staphylococcus aureus in 3 (2%), gram-negative enterobacteria in 5 (4%), Moraxellacatarrhalis in 2 (2%), and viruses in 4 (3%). The yields from laboratory tests were 48% for paired serology, 20% from adequate sputum sample, and 3% from blood culture. Conclusion: Our study shows that a large percentage of mild CAP cases are admitted to hospitals in Kuwait. Atypical pathogens have a significant role in the etiology of CAP. There is overtreatment of CAP with a combination treatment consisting mainly of third-generation chephalosporins and macrolides.

A modified indirect fluorescent antibody test for the diagnosis of brucellosis.

We adapted the conventional indirect fluorescent antibody (IFA) test to assay IgM and IgG Brucella-specific antibodies to differentiate acute from chronic infections rather than measure total antihuman globulin specific antibodies. The results were compared with the slide agglutination test (SAT) used for screening and the quantitative microagglutination test (MAT). Of a total of 118 randomly selected samples sent for anti-Brucella antibodies received at a general hospital laboratory, 58 (47.9%) were found to be positive for IFA-IgG test but not necessarily by other tests. Eleven of these cases were positive for Brucella melitensis by culture. Sixty serum samples found negative for Brucella antibodies by IFA and other tests were of patients with medical conditions other than brucellosis. Fifty serum samples from healthy blood donors were negative for Brucella spp. antibodies by all the three tests. The IFA test was found to be a more sensitive test than MAT and distinguished an acute infection from chronic disease.

Indirect fluorescent antibody test versus enzyme-linked immunosorbent assay and agglutination tests in the serodiagnosis of patients with brucellosis.

Abstract Anti-Brucella IgG, IgM and IgA in sera from patients with blood culture positive for B. melitensis and controls were measured by indirect fluorescent antibody (IFA) test and the findings compared with those of enzyme-linked immunosorbent assay (ELISA) and microagglutination test (MAT). Brucella melitensis and B. abortus antigens from three vendors (BioMerieux, Wellcome and Oxoid) and from reference strains (Ames, Iowa) were used in IFA and MAT while a whole cell heat-killed B. melitensis antigen was used in ELISA. Statistical analysis showed comparable results when using B. melitensis or B. abortus antigen, in IFA, from the same manufacturer but there were subtle differences among antigens from different manufacturers. Correlation between IFA and ELISA titers was poor, due to differences in the levels of these titers. However, the percentage of sensitivity, specificity, predictive positive, and predictive negative at different titers indicated the most reliable discriminative titers to be as follows: ELISA IgG 1 : 800 (100% for all), IgM 1 : 400 (100%, 93%, 100%, 100%, respectively) and IgA 1 : 200 (95%, 100%, 100%, 94%, respectively); IFA IgG 1 : 320 (95%, 93%, 95%, 93%, respectively) and IgM 1 : 80 (95%, 100%, 100%, 94%, respectively). IFA IgA showed either poor sensitivity or specificity at all titers. These findings and the subjective reading of IFA limit its value in Brucella diagnosis while the MAT showed high false negatives (5%–40%). Thus, ELISA proves to be the most reliable test for the diagnosis of patients with brucellosis.

Frequency and Clinical Association of Panton-Valentine Leukocidin-Positive Staphylococcus aureus Isolates: A Study from Kuwait

Objective: This study was undertaken to determine the frequency of Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus among strains isolated in our laboratory and to study the association of PVL-positive strains with clinical disease. Materials and Methods: A total of 291 S. aureus isolates obtained from different clinical specimens from June 1, 2009, to March 31, 2010, at the Farwania Hospital Laboratory were investigated for antimicrobial susceptibility, carriage of genes for PVL, and SCCmec elements. Antimicrobial susceptibility testing was performed by standard methods. The presence of mecA genes for PVL SCCmec typing was determined by PCR. Results: Of the 291 S. aureus isolates, 89 (30.6%) were methicillin-resistant S. aureus (MRSA), whereas 202 (69.4%) were methicillin susceptible (MSSA). Genes for PVL were detected in 13 (14.6%) and 24 (12.0%) of the MRSA and MSSA isolates, respectively. The majority of the PVL-producing MRSA and MSSA were isolated from 12 (30.7%) and 19 (21.8%) cases of skin and soft tissue infections (SSTI), respectively. Although both MSSA and MRSA strains were uniformly susceptible to rifampicin, teicoplanin, and vancomycin, multidrug resistance was observed among PVL-producing and nonproducing MRSA isolates. Both MRSA types carried SCCmec type III, IV, IVc, and V genetic elements. Conclusion: This study revealed the presence of genes for PVL in both MSSA and MRSA, associated mostly with SSTI and respiratory tract infections, supporting previous observations that PVL production is widespread among S. aureus strains obtained from different clinical sources.

In vitro Activity of Conventional and Newer Antimicrobial Agents against Brucella melitensis Clinical Isolates from Kuwait

The in vitro activity of 15 antimicrobial agents was tested against 21 clinical isolates of Brucella melitensis from Kuwait. The minimum inhibitory concentration for 90% of strains (MIC 90) was determ

Classical Presentation of Acute Pyelonephritis in a Case of Brucellosis

Although Brucella species is known to affect almost all organs in humans, renal involvement presenting as acute pyelonephritis remains a rare entity in brucellosis. We report the case of a female patient who presented with symptoms of fever with chills, right loin pain and dysuria in the emergency room. Blood cultures drawn at the time of admission grew Brucella spp., but no organisms were isolated from urine culture although urinalysis data was indicative of urinary tract infection. Empiric therapy with piperacillin/tazobactam plus gentamicin relieved her symptoms. However, the treatment was switched to doxycycline plus rifampicin once the blood culture result was obtained.

Genetic Lineages of Methicillin-Resistant Staphylococcus aureus Acquired during Admission to an Intensive Care Unit of a General Hospital

Objectives: The objectives of this study were to determine the frequency of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection while on admission to the intensive care unit (ICU), and examine the genetic backgrounds of the MRSA isolates to establish transmission among the patients. Subjects and Methods: This study involved screening 2,429 patients admitted to the ICU of Farwania Hospital from January 2005 to October 2007 for MRSA colonization or infection. The MRSA isolates acquired after admission were investigated using a combination of molecular typing techniques to determine their genetic backgrounds. Results: Of 2,429 patients screened, 25 (1.0%) acquired MRSA after admission to the ICU. Of the 25 MRSA, 19 (76%) isolates belonged to health care-associated (HA-MRSA) clones: ST239-III (n = 17, 68%) and ST22-IV (n = 2, 8%). The remaining 6 MRSA isolates belonged to community-associated clones: ST80-IV (n = 3, 12%), ST97-IV (n = 2, 8%), and ST5-IV (n = 1, 4%). The ST239-III-MRSA clone was associated with infection as well as colonization, and was isolated from patients from 2005 to 2007. Conclusions: The HA-MRSA clone ST239-III persistently colonized patients admitted to the ICU, indicating the possibility of its transmission among the patients over time.