Wadha Alfouzan

Isolation of Salmonella enterica Serovar Kentucky Strain ST 198 and Its H2S-Negative Variant from a Patient: Implications for Diagnosis

ABSTRACT H2S-producing multiresistant Salmonella enterica serovar Kentucky strain sequence type (ST) 198 and its non-H2S-producing variant were isolated from a patient. Whole-genome comparison showed a base addition in the gene encoding molybdenum cofactor biosynthesis protein C, which could affect H2S production in the variant. Lack of H2S production has implications for diagnosis of salmonella.

Increasing prevalence, molecular characterization and antifungal drug susceptibility of serial Candida auris isolates in Kuwait

Candida auris is an emerging yeast pathogen of global significance. Its multidrug-resistant nature and inadequacies of conventional identification systems pose diagnostic and therapeutic challenges. This study investigated occurrence of C. auris in clinical specimens in Kuwait and its susceptibility to antifungal agents. Clinical yeast strains isolated during 3.5-year period and forming pink-colored colonies on CHROMagar Candida were studied by wet mount examination for microscopic morphology and Vitek 2 yeast identification system. A simple species-specific PCR assay was developed for molecular identification and results were confirmed by PCR-sequencing of rDNA. Antifungal susceptibility testing of one isolate from each patient was determined by Etest. The 280 isolates forming pink-colored colonies on CHROMagar Candida, were identified by Vitek 2 as Candida haemulonii (n = 166), Candida utilis (n = 49), Candida kefyr (n = 45), Candida guilliermondii (n = 9), Candida famata (n = 6) and Candida conglobata (n = 5). Species-specific PCR and PCR-sequencing of rDNA identified 166 C. haemulonii isolates as C. auris (n = 158), C. haemulonii (n = 6) and Candida duobushaemulonii (n = 2). C. auris isolates originated from diverse clinical specimens from 56 patients. Of 56 C. auris isolates tested, all were resistant to fluconazole, 41/56 (73%) and 13/56 (23%) were additionally resistant to voriconazole and amphotericin B, respectively. Eleven (20%) isolates were resistant to fluconazole, voriconazole and amphotericin B. One isolate was resistant to caspofungin and micafungin. Increasing isolation of C. auris in recent years from diverse clinical specimens including bloodstream shows that C. auris is an emerging non-albicans Candida species in Kuwait causing a variety of infections. Inability of conventional identification methods to accurately identify this pathogen and multidrug-resistant nature of many strains calls for a greater understanding of its epidemiology, risk factors for acquiring C. auris infection and management strategies in high-risk patients. This is the first comprehensive study on the emergence of this multidrug-resistant yeast from Kuwait and the Middle East.

Pharmacodynamics of minocycline against Acinetobacter baumannii studied in a pharmacokinetic model of infection

Minocycline (MNO) is an old antibiotic that may have an important role in the treatment of multidrug-resistant Gram-negative bacterial infections as the burden of such infections increases. In this study, a single-compartment dilutional pharmacokinetic model was used to determine the relationship between MNO exposure and antibacterial effect, including the risk of resistance emergence, against strains of Acinetobacter baumannii. The mean ± standard deviation area under the unbound drug concentration-time curve to minimum inhibitory concentration ratio (fAUC/MIC) associated with a 24-h bacteriostatic effect was 16.4 ± 2.6 and with a -1 log reduction in bacterial load at 24 h was 23.3 ± 3.7. None of the strains reached a -2 log reduction over 48 h. Changes in population profiles were noted for two of the three strains studied, especially at fAUC/MIC ratios of >5-15. A reasonable translational pharmacodynamic target for MNO against A. baumannii could be an fAUC/MIC of 20-25. However, if maximum standard 24-h doses of intravenous MNO are used (400 mg/day), many strains would be exposed to MNO concentrations likely to change population profiles and associated with the emergence of resistance. Either MNO combination therapy or an increased MNO dose (>400 mg/day) should be considered when treating A. baumannii infections.

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.

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.

Comparison of the VITEK 2 antifungal susceptibility system with Etest using clinical isolates of Candida species

BACKGROUND Candida species are part of the normal human microbiota. However, in recent years, nosocomial bloodstream Candida infections have emerged as a significant problem ranking the fourth common cause of fungemia in intensive care units. Although microdilution methods are the ones recommended for susceptibility testing, they are difficult to undertake in the clinical practice. Thus, an automated commercially available test is ideal. AIMS To compare minimum inhibitory concentrations (MICs) obtained with the recently introduced Vitek 2 yeast susceptibility system card (AST-YS01) with Etest. METHODS 263 clinical Candida isolates representing six species were included in the study. Categorical agreements (CA) were assessed as described elsewhere. RESULTS Irrespective of the Candida species tested, the overall CA between Vitek 2 and Etest ranged between 66.7% and 100%. In general, Etest yielded lower MICs than Vitek 2. For Candida albicans, the CA between Vitek 2 and Etest was >95% for amphotericin B, voriconazole and flucytosine, but only 89% for fluconazole. With respect to Candida glabrata, the CA was between 97% and 100%. The major errors were with Candida krusei and flucytosine and Candida kefyr and amphotericin B. Candida tropicalis susceptibility for fluconazole by Vitek 2 reported more SDD and resistant strains than Etest. Candida parapsilosis showed 100% CA against all the four antifungals tested. No very major errors were detected between the two methods. CONCLUSIONS Vitek 2 provided comparable results to Etest with quick turnaround for the testing of Candida species susceptibilities.

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.

Epidemiological Study on Species Identification and Susceptibility Profileof Candida in Urine

Background: There have been important changes in the epidemiology of Candida causing urinary tract infection (UTI) over the past decades. Candida species other than Candida albicans have now emerged as an important cause of UTI and some of which exhibit reduced susceptibility to commonly used antifungal agents. The aim of this study was to investigate species distribution and antifungal susceptibility profile of Candida species causing candiduria in Farwania hospital in Kuwait and asses its’ associated risk factors. Materials and method: During a 12-month period, urine cultures were processed for isolation of Candida species. All the yeast isolates were sub-cultured on Sabouraud dextrose agar and processed for phenotypic identification by germ tube test and API ID 32C. Antifungal susceptibilities of the isolates were determined against amphotericin B, voriconazole, fluconazole and caspofungin by E-test. All the patients yielding Candida species in urine culture were assessed for risk factors. Results: Of 13691 urine samples processed for culture, 2550 (18.6%) yielded microbial growth. Of these, 85 (3.3%) were identified as Candida UTI (CUTI) with an incidence of 3.3%. The ratio of female to male was 2:1. The average age of the patients was 54 yrs. The most common isolate was C. albicans (54%) followed by C. tropicalis (15%). The major predisposing factors were urinary tract catheterization (86.5%) and antibiotic therapy (68%). Conclusion: The study reinforces the emerging importance of non-albicans Candida species in the epidemiology of candiduria. A better understanding of the associated risk factors and knowledge of susceptibility profile of the local Candida isolates may have therapeutic benefits.

Retrospective Clinical and Microbiologic Analysis of Patients with Anorectal Abscess

BACKGROUND We conducted a clinical and microbiologic analysis of patients presenting with anorectal abscess. METHODS A total of 505 adult patients presenting from January 2011 to December 2017 were analyzed retrospectively. Microbiologic data were available for 211 patients. RESULTS The mean age at presentation was 39.5 (standard deviation 12.4) years, and 81.4% of the cohort were men. One hundred fifteen patients (22.8%) had diabetes mellitus, and 15 patients (3.0%) had inflammatory bowel disease. There were 184 patients (36.4%) who required admission for more than 24 hours with a median length of stay of two days (interquartile range 2, 4) days. The most common microorganism was Escherichia coli (37.6%), followed by Bacteroides spp. (13.2%) and Streptococcus spp. (13.2%). Escherichia coli accounted for 34.9% of the microorganisms cultured from patients with diabetes mellitus followed by Streptococcus spp. (27%) and Klebsiella pneumoniae (20.6%). CONCLUSIONS Escherichia coli is the most common micro-organism cultured from patients presenting with anorectal abscess. Despite an increase in community-acquired multi-resistant strains, our results show a low overall incidence of such isolate. Our study provides a large microbiologic sample of patients with anorectal abscess to expand the present knowledge of the etiology of a common surgical condition.

In Vitro Activity of Newer and Conventional Antimicrobial Agents, Including Fosfomycin and Colistin, against Selected Gram-Negative Bacilli in Kuwait

Limited data are available on susceptibilities of these organisms to some of the recently made accessible antimicrobial agents. The in vitro activities of newer antibiotics, such as, ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CZA) along with some “older” antibiotics, for example fosfomycin (FOS) and colistin (CL) were determined against selected strains (resistant to ≥3 antimicrobial agents) of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Minimum inhibitory concentrations (MIC) were determined by Clinical and Laboratory Standards Institute microbroth dilution. 133 isolates: 46 E. coli, 39 K. pneumoniae, and 48 P. aeruginosa were tested. Results showed that E. coli isolates with MIC50/90, 0.5/1 μg/mL for CL; 4/32 μg/mL for FOS; 0.25/32 μg/mL for C/T; 0.25/8 μg/mL for CZA, exhibited susceptibility rates of 95.7%, 97.8%, 76.1%, and 89.1%, respectively. On the other hand, K. pneumoniae strains with MIC50/90, 0.5/1 μg/mL for CL; 256/512 μg/mL for FOS; 2/128 μg/mL for C/T; 0.5/128 μg/mL for CZA showed susceptibility rates of 92.3%, 7.7%, 51.3%, and 64.1%, respectively. P. aeruginosa isolates with MIC50/90, 1/1 μg/mL for CL; 128/128 μg/mL for C/T; 32/64 μg/mL for CZA presented susceptibility rates of 97.9%, 33.3%, and 39.6%, respectively. Higher MICs were demonstrated against most of the antibiotics. However, CL retained efficacy at low MICs against most of the isolates tested.