Cracking the Code: Unveiling the Diversity of Carbapenem-Resistant Klebsiella pneumoniae Clones in the Arabian Peninsula through Genomic Surveillance

The rise of antimicrobial resistance is a global challenge that requires a coordinated effort to address. In this study, we examined the genetic similarity of carbapenem-resistant Klebsiella pneumoniae (CRKP) in countries belonging to the Gulf Cooperation Council (GCC) to gain a better understanding of how these bacteria are spreading and evolving in the region. We used in silico genomic tools to investigate the occurrence and prevalence of different types of carbapenemases and their relationship to specific sequence types (STs) of CRKP commonly found in the region. We analyzed 720 publicly available genomes of multi-drug resistant K. pneumoniae isolates collected from six GCC countries between 2011 and 2020. Our findings showed that ST-14 and ST-231 were the most common STs, and 51.7% of the isolates carried bla_OXA-48-like genes. Additionally, we identified rare carbapenemase genes in a small number of isolates. We observed a clonal outbreak of ST-231 in Oman, and four Saudi isolates were found to have colistin resistance genes. Our study offers a comprehensive overview of the genetic diversity and resistance mechanisms of CRKP isolates in the GCC region that could aid in developing targeted interventions to combat this pressing global issue.

Elucidating the virulence genes harboured by carbapenemase- and non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae rectal isolates from patients admitted to intensive care units using whole-genome sequencing in Kuwait

Introduction. Klebsiella pneumoniae is a Gram-negative pathogen responsible for community- and nosocomial-acquired infections. The presence of an accessory genome determines the bacterial pathogenicity and the host immune response, and thus indicates multidrug-resistant strains or more virulent groups. Little is known about the virulence genes in K. pneumoniae in Kuwait.Hypothesis/Gap Statement. The diversity of virulence genes and capsule loci in K. pneumoniae isolates warrants further genomic studies to better understand their transmission within the hospitals in Kuwait.Aim. We aimed to investigate the virulence genes harboured by K. pneumoniae isolated from rectal swabs of intensive care unit (ICU) patients in two Kuwaiti teaching hospitals.Methodology. Six isolates from patients in the ICUs of Al Razi and Mubarak hospitals, designated RZH144, RZH132 RZH108 and RZH173, and MKH381 and MKH347, respectively, were subjected to whole-genome sequencing (WGS) assays. RZH144 and RZH132 were non-carbapenemase-producing K. pneumoniae (NCKP) isolates negative for genes encoding carbapenemase production by PCR assays, and the remaining four were carbapenemase-producing K. pneumoniae (CPKP) isolates. Isolates were characterized by phenotypic, PCR and WGS methods. Susceptibility testing was performed by E test and clonality by multilocus sequence typing. Analysis of the isolates' assembled contigs was carried out using Kleborate (https://pathogen.watch).Results. An NCPE RZH132 K. pneumoniae isolate belonged to ST231-wzi104 and harboured gene clusters encoding the biosynthesis of the siderophore aerobactin (iuc5) on 62-3LV. The capsular locus variants were KL51 and O locus O1v2. Another NCPKP RZH144 isolate was confirmed as ST43-wzi412 and harboured KL61 and O1v1. The four CPKP isolates harboured two virulence loci - ybt14 and iuc5 - encoding the siderophores yersiniabactin and aerobactin, respectively. They belonged to ST231-wzi104 and harboured yersiniabactin on ICEKp5. The sequence type of ybt was YbST145-1LV. Strain RZ108 was devoid of virulence loci. Its sequence type was ST15-wzi151 and harboured KL48 and O1V1. ST231 clonal lineage isolates shared common virulence plasmid variants.Conclusion. The CPKP ST231 had the highest virulence score and contained iuc5, which was found for the first time in ST231-CPKP isolates in Kuwait.

Prevalence of carbapenem-resistant Enterobacteriaceae and emergence of high rectal colonization rates of blaOXA-181-positive isolates in patients admitted to two major hospital intensive care units in Kuwait

BACKGROUND

Fecal colonization by carbapenem-resistant Enterobacteriaceae (CRE) can be the main reservoir for transmission of these resistant organisms especially in the Intensive Care Units (ICUs).

AIM

This study was conducted to evaluate the rate of rectal carriage and molecular characterization of CRE in patients hospitalized in the ICUs of 2 major hospitals (Adan and Mubarak Al Kabeer Hospitals) in Kuwait.

MATERIALS AND METHODS

Rectal swabs were collected from all patients at admission, 48 h after admission and once weekly from April 2017- March 2018. Initial CRE screening was carried out on MacConkey agar on which meropenem disc 10μg was placed. Identification of isolates was by API 20E. Susceptibility testing was performed using the E-test method. Polymerase chain reaction (PCR) was used to detect the carbapenemase-encoding genes. Clonal relationship was investigated by pulsed-field electrophoresis (PFGE). Genes of blaOXA-181 and blaNDM-5-carrying plasmids were detected in some strains.

RESULTS

A total of 590 patients were recruited into the study. Of these, 58 were positive for CRE, giving a prevalence of 9.8%; 25/320 (7.8%) in Adan and 33/270 (12.2%) in Mubarak Al Kabeer Hospitals. All isolates were resistant to multiple antibiotics. Resistance rates to colistin and tigecycline were 17% and 83%, respectively. Single genes of blaOXA-181 were detected in isolates from 38 (65.5%) out of 58 patients and in 5 patients colonized by blaOXA-48-positive CRE. A combination of 2 genes was detected in 12 isolates; 5 blaKPC-2 and blaOXA-181, 4 blaVIM-1 and blaOXA-181, and 3 blaNDM-5 and blaOXA-181. PFGE showed an overall level of similarity of 38%. Southern hybridization studies localized the blaOXA-181 and blaNDM-5 genes to a large plasmid of 200kb in 3 K. pneumoniae isolates and a small plasmid of 80kb in 2 E. coli isolates, respectively.

CONCLUSION

The prevalence of CRE colonization in the 2 hospital ICUs was relatively high and the emergence of blaOXA-181-mediated CRE is a cause for concern as there is the possibility of rapid horizontal spread among hospital patients in Kuwait. Active surveillance of CRE in the ICUs is highly recommended to stem its spread.

535. Multicenter Study of the Prevalence of Rectal Colonization by Carbapenem-Resistant Enterobacteriaceae in Patients Admitted to the Intensive Care Units of 7 Major Hospitals in Kuwait

Background

The emergence of carbapenem-resistant Enterobacteriaceae (CRE) has become an important epidemiological change in infectious diseases in the last 10 years. The gut is an important reservoir for these isolates thereby creating an opportunity for dissemination in a hospital setting especially the intensive care units (ICUs). The objective of this study was to investigate the colonization rates of patients, by CRE, admitted to the ICUs of 7 teaching hospitals.

Methods

Rectal swabs were collected during July 2017 to November 2018 from all patients on the day of ICU admission and 1 week after in each hospital. The samples were screened by direct plating on MacConkey agar containing 10-μg meropenem. Bacterial species identification was performed using the VITEK-2 system. The minimum inhibitory concentrations (MICs) of 14 antibiotics were determined by using Etest. Genes encoding carbapenem resistance was detected by PCR and sequencing. Their clonal relationship was determined by pulsed-field gel electrophoresis (PFGE).

Results

A total of 2580 Enterobacteriaceae were isolated from all patients. Seventy-four (2.9%) were confirmed as CRE most of which were from patients in Adan (AH: 36.5%) and Mubarak (MH: 46%) hospitals. Sixty (81.1%) harbored one or more of the tested carbapenemases genes. Forty-six (62.2%) carried bla_OXA-181, 9 (12.2%) bla_OXA-48, one bla_KPC-2, while 14 (18.9%) carried 2 genes. Combinations of bla_KPC-2 and bla_OXA-181 genes were found in 5 (6.8%), bla_VIM-1 and bla_OXA-181 in 4 (5.4%), bla_NDM-5 and bla_OXA-181 in 3 (4.1%) and bla_NDM-1 and bla_OXA-181 in 2 (3.3%). The XbaI PFGE profile-based Dendrogram, at 85% similarity criterion, resolved 7 pulsotypes among isolates carrying bla_OXA-181 in AH and MH designated A, B, C, D, E, F, and G. Further analysis revealed that 7 subpulsotypes A1, A2, A5, A6, C1, C2, and E1 were from unit D in the medical ICU of MH and A3, A4, B1, B3, D1, D2, D3, D4, F1, F2, F3, G1, and G2 were from surgical/medical ICUs in AH. 100% similarity was demonstrated among 8 isolates from AH and 2 from MH.

Conclusion

The prevalence of rectal colonization by CRE in the ICU patients was lower than expected. Detection of bla_OXA-181 variety and bla_NDM-5 is new to the milieu of genes so far described in isolates from Kuwait.

Disclosures

All authors: No reported disclosures.

High Prevalence of New Delhi Metallo-β-Lactamase-1 (NDM-1) Producers among Carbapenem-Resistant Enterobacteriaceae in Kuwait

The aim of the study was to determine the prevalence of New Delhi metallo-β lactamase-1 (NDM-1) producing Enterobacteriaceae in Kuwait over a one year period. Consecutive Enterobacteriaceae isolates with reduced susceptibility to carbapenems were collected from four government hospitals in Kuwait from January–December 2014. Their susceptibility to 18 antibiotics was performed by determining the minimum inhibitory concentration. Isolates resistant to carbapenems were tested by PCR for resistant genes. Finger printing of the positive isolates was done by DiversiLab^®. Clinical data of patients harboring NDM-1 positive isolates were analyzed. A total of 764 clinically significant Enterobacteriaceae isolates were studied. Of these, 61 (8%) were carbapenem-resistant. Twenty one out of these 61 (34.4%) were NDM-1-producers. All patients positive for NDM-1-carrying bacteria were hospitalized. About half were females (11/21 [52.3%]), average age was 53.3 years and the majority were Kuwaitis (14/21 [66.6%]). Six patients (28.5%) gave a history of travel or healthcare contact in an endemic area. Mortality rate was relatively high (28.6%). The predominant organism was Klebsiella pneumoniae (14 [66.6%]) followed by E. coli (4 [19%]). All NDM-1-positive isolates were resistant to meropenem, ertapenem, cefotaxime, cefoxitin and ampicillin, while 95.2% were resistant to imipenem, cefepime, and piperacillin-tazobactam. They were multidrug resistant including resistance to tigecycline, but 90% remained susceptible to colistin. About two-thirds of isolates (61.9%) co-produced-extended spectrum β-lactamases. During the study period, an outbreak of NDM-1 positive K. pneumoniae occurred in one hospital involving 3 patients confirmed by DiversiLab^® analysis. In conclusion, NDM-1-producing Enterobacteriaceae is a growing healthcare problem with increasing prevalence in Kuwait, especially in hospitalized patients, leaving few therapeutic options. A high prevalence of NDM-1 necessitates the implementation of strict infection control to prevent the spread of these organisms.

Comparative evaluation of two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems for the identification of clinically significant yeasts

OBJECTIVES

To prospectively evaluate the performance of two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry systems (MALDI-TOF MS) for the identification of clinically significant yeast isolates compared to the VITEK 2 system.

METHODS

One hundred and eighty-eight consecutive yeast isolates were analyzed by Bruker Biotyper and VITEK MS. The results were compared with the conventional VITEK 2 yeast identification system. Discrepant results were resolved by direct sequencing of rDNA.

RESULTS

Accurate identification by VITEK 2, VITEK MS, and Bruker Biotyper MS was 94.1% (177/188), 93.0% (175/188), and 92.6% (174/188), respectively. Three isolates were not identified by VITEK MS, while nine Candida orthopsilosis were misidentified as Candida parapsilosis, as this species is not present in its database. Eleven isolates were not identified or were wrongly identified by Bruker Biotyper and although another 14 were correctly identified, the score was unreliable at <1.7.

CONCLUSION

The overall accuracy of rapid MALDI-TOF MS systems was essentially comparable to that of the conventional VITEK 2 yeast identification system. However, future expansion of the databases may further improve the outcome and accuracy of identification of yeast species.

Comparison of two matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry methods and API 20AN for identification of clinically relevant anaerobic bacteria

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is suitable for high-throughput and rapid microbial diagnosis at relatively low cost and can be considered an alternative to conventional biochemical and molecular identification systems in clinical microbiological laboratories, including anaerobe laboratories. Two commercially available MALDI-TOF MS systems, Bruker Microflex MS and bioMérieux VITEK MS, were evaluated for the identification of 274 isolates of clinically significant anaerobic bacteria recovered from routine cultures of clinical specimens in parallel with blinded comparison with conventional biochemical (API 20AN) or molecular methods. All were recovered cultures obtained from patients attending the Mubarak Al Kabir Hospital, Kuwait, during a 6 month period. Discrepant results after two attempts at direct colony testing had failed to provide acceptable MALDI-TOF identification were resolved by gold-standard 16S gene sequencing. The VITEK MS gave high-confidence identification of the 274 isolates, all of which were correctly identified. The Bruker Microflex MS system also gave high-confidence identification for 272 of the 274. After discrepancy testing, the Bruker MS results agreed with biochemical or molecular methods for 89.1 % of the isolates at species level and 10.2 % at genus level (0.72 % were misidentified). The level of agreement with the VITEK MS was 100 % at both species and genus level; no isolates were misidentified. Our data suggest that implementation of MALDI-TOF MS as a first step for identification will shorten the turnaround time and reduce the cost in the anaerobe laboratory.

Correlation of multidrug resistance, toxinotypes and PCR ribotypes in Clostridium difficile isolates from Kuwait

Clostridium difficile is a common cause of nosocomial diarrhea. its role in community-acquired diarrhea is also becoming an important public health concern. Hardly any studies have correlated strain ribotypes, toxinotypes and multidrug resistant (MDR) profiles. To investigate these characteristics, 65 C. difficile isolates obtained from stool samples of patients whose cultures were negative on admission but became positive after 48 h of admission to the ICUs of our hospitals were studied to determine the prevalent ribotypes, toxinotypes and their relationship with the MDR profiles using ELISA/cytotoxicity assays, PCR and Etest methods. The toxin-producing strains were toxinotyped by the PCR-RFLP technique. Of the 65 isolates, 42 (64.6%) were toxigenic (T). The isolates were of diverse ribotypes but types 097, 078, 056 and 039 (NT) were predominant. thirty (71.4%) of 42 T and 13 (56.5%) of 23 NT strains were multiresistant to 3 or more antibiotics. Only 3 toxinotypes (0, "V-like" and XII) were encountered. Of the 42 t strains, 30 (71.4%) were of toxinotype 0, and 12 belonged to variant toxinotypes: 4 (9.4%) to toxinotype XII and 8 (19%) to "V-like" toxinotype in which amplified B1 PCR fragments was amplified as expected for toxinotype V but the A3 PCR fragment could not be amplified. The 43 mDR strains were assigned to 3 arbitrary resistance groups; groups 1, 11 and III. the most prevalent isolates (37; 86.1%) were in group II. Of the predominant T ribotypes (097, 078 and 056), c. 62% clustered in group II. Although the number of strains toxinotyped was small, ribotyping and toxinotyping correlated well with the published literature, except for 078 with a novel "V-like" toxinotype. Antibiogram was not as clear-cut.

Comparative in vitro activity of tigecycline and nine other antibiotics against gram-negative bacterial isolates, including ESBL-producing strains

The enterobacteriaceae, especially Escherichia coli and Klebsiella spp., as well as Acinetobacter spp., are important agents of nosocomial infections in hospitalized patients. A total of 460 Gram-negative bacteria (GNb), were investigated for their susceptibility to tigecycline and 9 other antibiotics by the etest. ESBL production was inferred from ESBL etest phenotypes. All the GNb, including the ESBL-producers, were susceptible to tigecycline with MIC(90 )ranges of 0.25 to 2 microg/ml. Imipenem and meropenem were very active against ESBL and non-ESBL producers; mean MIC(90)s of 0.19 and 0.09 microg/ml and 0.05 microg/ml and 0.02 microg/ml, respectively. The MIC(90)s of imipenem and meropenem for the Acinetobacter spp. were 16 and >32 microg/ml, respectively with resistance rates of 64.3 and 66.1%. ESBL production was detected in 62% and 82.1% of the E. coli and K. pneumoniae isolates, respectively. Resistance to ciprofloxacin was higher among the ESBL-producing strains of E. coli and K. pneumoniae than the non-ESBL producers. Comparatively, tigecycline had excellent in vitro activities against ESBL-producing enterobacteriaceae and demonstrated superior activity against Acinetobacter spp. Increasing ESBL production and resistance to ciprofloxacin and gentamicin in enterobacteriaceae require careful selection of empirical therapy. Tigecycline holds promise as an alternative choice of therapy for infections caused by ESBL-producing isolates and multi-drug resistant Acinetobacter spp.

A study of the bacterial flora before and after antiseptic skin preparation of the perineum in male urology patients

OBJECTIVE

To establish the bacterial flora of the perineum before and after antiseptic preparation in male urology patients.

PATIENTS/METHODS

Adult male patients undergoing cystoscopic procedures were studied. Three sets of swab specimens, labelled A, B and C, were taken from the perineum in the theatre. Specimen A was taken before cleaning and disinfection of the skin with Savlon (Chlorhexidine- cetrimide mixture), specimen B after disinfection and draping, and C after completion of the operative procedure. Specimens were processed on standard laboratory media for aerobic and anaerobic bacteria and yeasts.

RESULTS

Of the 114 patients studied, 43 (37.7%) had a positive culture for significant microorganisms in specimen A, 7 (6.1%) in specimen B and 13 (11.4%) in specimen C (A vs. B p < 0.001, A vs. C p < 0.001, B vs. C p < 0.01). The commonest isolates in specimen A were Gram-positive organisms (84.1%). The positive-culture rate for patients with end-stage renal failure was 71.4%, for those with a urethral catheter it was 53.8%, for those without systemic diseases it was 36.6% and for patients with diabetic mellitus it was 28.1%.

CONCLUSION

About 38% of patients undergoing cystoscopic procedures had a significant positive perineal culture, with Staphylococcus species being the predominant skin flora. The bacteria culture rate was affected by the presence of systemic diseases. The use of Savlon to disinfect the perineum resulted in a significant reduction in the bacterial count of the perineum.

Listeria monocytogenes meningitis in an immunocompetent adult patient

OBJECTIVE

To report an interesting case of meningitis caused by Listeria monocytogenes in an immunocompetent adult.

PATIENT AND METHODS

A previously healthy 25-year-old man presented with typical clinical features of meningitis. Cerebrospinal fluid (CSF) was obtained on the day of admission for biochemical and microbiological investigations. In addition, blood was also taken for culture and hematological studies. Antibiotic susceptibility test was performed using the Etest method. Microscopic examination of the CSF showed pleocytosis, which was predominantly lymphocytic, while the biochemical investigation revealed raised concentrations of protein and lactic acid as well as decreased glucose concentration. A 24-hour culture yielded pure growth of gram-positive bacilli identified by standard methods as L. monocytogenes. It was susceptible to ampicillin and trimethoprim-sulfamethoxazole. The patient was treated with intravenous ampicillin combined with gentamicin and made a complete recovery.

CONCLUSION

This presentation describes an unusual case of meningitis caused by L. monocytogenes in a previously healthy young adult with no risk factor. Only a few similar cases have been reported in the literature.

Molecular characterization of nitroimidazole resistance in metronidazole-resistant bacteroides species isolated from hospital patients in Kuwait

OBJECTIVES

The aim of this study was to screen for infections caused by metronidazole (MTZ)-resistant Bacteroides spp., and to characterize the genes that encode the MTZ resistance.

MATERIALS AND METHODS

A total of 7 MTZ-resistant Bacteroides spp. were isolated from 5 patients with MTZ-resistant infections. These organisms were investigated for carriage of genes that encode MTZ resistance. The presence of these genes was investigated by PCR and the PCR products were subjected to PCR-RFLP analysis.

RESULTS

The strains were MTZ-resistant with minimum inhibitory concentrations of > 32 microg/ml. The presence of nim genes was indicated by PCR in all 7 strains. PCR-RFLP analysis of the nim gene products demonstrated two of the five reported resistance genes, nimA-nimE. These two resistance genes were nimE in 5 of the 7 isolates and nimA in 2 strains.

CONCLUSION

MTZ-resistant Bacteroides spp. have been isolated from patients in Kuwait. Nim genes, specifically nimE and nimA, mediate the drug resistance in these isolates. The methods used in detecting these genes are rapid, accurate and relatively inexpensive and could be adopted easily to help in monitoring emergence of MTZ resistance determinants in Kuwait.

Prevalent PCR ribotypes of clinical and environmental strains of Clostridium difficile isolated from intensive-therapy unit patients in Kuwait

Ninety-five isolates of Clostridium difficile from symptomatic and asymptomatic patients and 18 from their environment in the intensive-therapy units (ITUs) of four teaching hospitals in Kuwait were typed by PCR amplification of rRNA intergenic spacer regions (PCR ribotyping). A total of 32 different ribotypes was detected among the clinical isolates. The predominant ribotypes from the clinical isolates were types 097 and 078, which accounted for approximately 40 % of all isolates in the ITUs in Kuwait. Ribotypes 097 (toxigenic), 078 (toxigenic) and 039 (non-toxigenic) were three distinct clones that were circulating in all four hospitals. Ribotypes 097, 078 and 076 (i.e. 50 % of isolates from symptomatic patients) were the predominant isolates associated with C. difficile-associated disease (CDAD). The environmental isolates belonged to a diverse range of ribotypes, with no particular types common to all the hospitals. Ribotype 078 was found only in the patient environment in Mubarak hospital, while ribotype 097 was restricted to Amiri hospital. The hospital environment occupied by symptomatic as well as symptom-free patients was contaminated with C. difficile. Eight new strains that did not match any in the PCR ribotype library established at the PHLS Anaerobe Reference Unit, Cardiff, UK, were assigned ribotypes 105, 125, 128, 129, 131, 134, 140 and 141. These findings show that the isolates associated with CDAD in Kuwait are different from those found in the UK and some other European countries.

Comparative in vitro activity of PH-027 versus linezolid and other anti-anaerobic antimicrobials against clinical isolates of Clostridium difficile and other anaerobic bacteria

PH-027 is a new 5-triazole oxazolidinone synthesized in our laboratories, which shows strong activity against gram-positive aerobic bacteria including clinical isolates. The objective of this study was to investigate the in vitro activity of this compound in comparison with linezolid and other antibiotics against gram-positive and gram-negative anaerobes. The in vitro activity of PH-027 in comparison with those of linezolid and other antimicrobial agents was evaluated against 201 clinical isolates of gram-positive and gram-negative anaerobic bacteria by agar dilution and Etest methods. PH-027 showed excellent activity, with minimum inhibitory concentrations (MIC) in the range of 0.12-4.0 microg/ml against all isolates; MIC90s being 4.0, 1.0, 2.0, 2.0 and 2.0 microg/ml against Clostridium difficile, Peptostreptococcus spp., Bacteroides fragilis, Prevotella bivia and Fusobacterium spp. respectively. In comparison, linezolid had MIC in the range of 0.5-4.0 microg/ml against all isolates, with MIC90s of 2.0, 4.0, 4.0, 4.0 and 2.0 microg/ml against the same set of bacteria respectively. PH-027 demonstrated excellent in vitro activity that is superior to linezolid against Peptostreptococcus spp., B. fragilis and P. bivia. However, against C. difficile and Fusobacterium spp, PH-027 and linezolid showed comparable in vitro activity. Against all anaerobes, metronidazole, PH-027 and, to a lesser extent, linezolid had the most potent activity. From the results of in vitro susceptibility testing, both linezolid and PH-027 show promise in the treatment of anaerobic infections.

In vitro activity of 15 antimicrobial agents against clinical isolates of Clostridium difficile in Kuwait

A total of 73 clinical isolates of Clostridium difficile isolated from stool/rectal swabs of patients admitted to the intensive care units at Mubarak Hospital, Ibn Sina Hospital Burn unit and Haematology wards at the Kuwait Cancer Control Centre, were investigated for their susceptibility to 15 antibiotics using the Etest. Amoxycillin-clavulanic acid, ampicillin, meropenem, metronidazole, penicillin, piperacillin, piperacillin/tazobactam, teicoplanin and vancomycin had excellent activities with MIC(90)s of 0.38, 0.5, 1, 0.19, 1.5, 2, 3, 0.25 and 0.75 mg/l, respectively. Of the 73 C. difficile isolates, 86% were resistant to imipenem (MIC(90) >32 mg/l) and almost 97% were resistant to trovafloxacin (MIC(90)>256 mg/l). Forty eight percent of the isolates were resistant to clindamycin. A total of 18 isolates were highly clindamycin-resistant with an MIC of >256 mg/l; 10 of these were toxin producers. Multiple antibiotic resistance (two or more antibiotics) was noted in 63 isolates. These were more common among the toxigenic strains than the non-toxigenic strains by a ratio of 2.5:1.

Hospital-acquired Clostridium difficile infection amongst ICU and burn patients in Kuwait

OBJECTIVES

To prospectively study the prevalence of nosocomially acquired Clostridium difficile, a major cause of diarrhoea in hospitalized patients, in the intensive care units (ICUs) and burn unit (BUs) of three teaching hospitals in Kuwait.

METHODS

During a 1-year prospective study, stool/rectal swabs were obtained from 344 patients admitted into the ICUs of Mubarak Hospital (ICU-1), the Kuwait Cancer Control Centre (ICU-2), and the BU of Ibn Sina Hospital. The presence of C. difficile and/or its toxin was detected by serially culturing the specimens on differential, selective and enriched media and the use of TOX-A/B test, on admission and at subsequent 1-weekly interval until discharge.

RESULTS

Out of the 344 patients admitted into these units, over a study period of 1 year, only 263 (77%) were evaluable. All of them had negative stool culture/toxin on admission. Overall, 25 (9.5%) of these 263 patients acquired C. difficile during their hospitalization. Thirteen (7%) of 187 patients acquired C. difficile in ICU-1, 9 (36%) of 25 on ICU-2 and 3 (5.9%) of 51 patients in BU. Eight (32%) developed diarrhoea attributable only to C. difficile and/or toxin, and the remaining 17 (68%) were asymptomatic: none had pseudomembranous colitis. The diarrhoea in these patients was associated with antibiotic use, the main trigger-antibiotics being the third-generation cephalosporins. Acquisition occurred within 4-53 days of admission, with the majority occurring in the first 15 days.

CONCLUSION

Overall, the prevalence of hospital-acquired C. difficile infection/colonization was less than 10%. The use of third-generation cephalosporins was high and was related to the development of diarrhoea. Once acquired, diarrhoea developed in about one third of C. difficile-positive cases, an indication that C. difficile infection/colonization endemic in the hospital ICUs studied is usually transmitted among the hospitalized patients.

Susceptibility of 497 clinical isolates of gram-negative anaerobes to trovafloxacin and eight other antibiotics

Trovafloxacin is a novel investigational trifluoronaphthyridone antibiotic with broad-spectrum activity against Gram-positive and Gram-negative organisms. Its in-vitro activity and those of eight other antimicrobial agents were evaluated against 497 clinical isolates of Gram-negative anaerobic bacteria by the agar dilution method. Trovafloxacin had excellent activity, with a minimum inhibitory concentration (MIC) range of <0.03-4 microg/ml, against all species. Out of the 497 isolates tested, 496 (99.5%) were inhibited by a concentration of < or = 2.0 microg/ml of trovafloxacin; the remaining two strains were inhibited by a concentration of 4.0 microg/ml. The MIC50s and MIC90s were 0.12 microg/ml and 1.0 microg/ml, respectively. Meropenem, imipenem and piperacillin/tazobactam were also very active. Overall, at the MIC90s, trovafloxacin was as active as meropenem, slightly more active than metronidazole and imipenem, twice as active as amoxicillin-clavulanic acid, five times more active than piperacillintazobactam and 68 times more active than clindamycin. About 21% of the isolates were resistant to cefoxitin, 30% to clindamycin and 40% to piperacillin. Five species in the Bacteroides fragilis group of isolates were highly resistant to metronidazole (MIC >128 microg/ml). In general, the relatively more resistant species were the B. vulgatus, B. ovatus, B. thetaiotaomicron, and B. fragilis sensu stricto, in that order. All the isolates of the B. fragilis group and about 50% of the Prevotella spp. were beta-lactamase positive. Trovafloxacin certainly holds promise as an alternative drug for therapy of anaerobic infections.

An analysis of hospital-acquired bacteraemia in intensive care unit patients in a university hospital in Kuwait

An analysis of hospital-acquired bacteraemia among ICU patients was carried out over a two-year period in order to determine the incidence, associated mortality rate and susceptibility pattern of causative pathogens. There was a high incidence of bacteraemia, occurring in 127 (18.4%) of 692 patients. Mortality attributable to nosocomial bacteraemia was 52% of the total 79 deaths from all causes. The highest mortality rate (58.5%) occurred in patients with fungal infections, whilst death from Gram-negative bacteraemia was only 17%. Over 98% of patients had underlying disease. Nearly half (46.8%) of 267 organisms isolated were Gram-positive. In comparison, Gram-negative bacteria accounted for 36.6% and the rest (17.6%) were fungi (mainly Candida albicans). The majority of the bactereamic episodes were monomicrobial (90.2%). Coagulase-negative staphylococci (CNS) were the commonest pathogens isolated, representing 32.6% of all organisms. Inducible beta-lactamase producing organism (Enterobacter spp. 9.7%, Serratia marcescens 6.7%, Klebsiella pneumoniae 6% and Pseudomonas aeruginosa 6%) formed the bulk of Gram-negative bacteria. In contrast, Escherichia coli (7.5%) and K. pneumoniae (4%) were the commonest Gram-negative bacteria from hospital-acquired bacteraemia in the general hospital population. The majority (80%) of CNS were resistant to methicillin (MRSE) but susceptible to vancomycin; they were relatively resistant to erythromycin, clindamycin and beta-lactams antibiotics. Whilst Gram-negative organisms were relatively susceptible to imipenem (85%), ciprofloxacin (88%) and amikacin (87%), they had unacceptably low levels of susceptibility to cefuroxime (59.3%), cefotaxime (71%), ceftazidime (60.9%), and piperacillin (51.1%). This study shows that hospital-acquired bacteraemia in ICU patients carries a poor prognosis. Information regarding the infective agents and their susceptibility in the ICU setting is valuable for the selection of empirical therapy before culture and susceptibility results are known.

Serogroups and antimicrobial susceptibility of clinical isolates of Salmonella species from a teaching hospital in Kuwait

Salmonella strains isolated in a teaching-cum-general hospital in Kuwait during 1990-1993 and 1996 were analysed to determine the trend in the prevalence of the serogroups and their changing pattern of susceptibility. The records were reviewed for all the 661 isolates encountered during these periods. The most prevalent serogroup in both children and adults was serogroup B, followed by serogroup C and D. A sizeable proportion of the strains were resistant to first-line drugs. About 39% of the isolates were resistant to ampicillin, 17% to co-trimoxazole, 13% to chloramphenicol, and 15% to cephalothin. The majority were, however, susceptible to the other drugs with low to very low resistance rates: 7% to amoxicillin/clavulanic acid, and 0.3% to cefotaxime. All the strains were susceptible to ciprofloxacin. In all, resistant strains were more prevalent among children than adults.

Prevalence and susceptibility of Shigella species to 11 antibiotics in a Kuwait teaching hospital

During the 5-year period 1990-1993 and 1996, 202 Shigella spp. were isolated from stool specimens of symptomatic patients of all age groups seen in our hospital. Over these periods the trend of the incidence of shigellosis showed that 18% of the total strains were isolated during the invasion year (1990) followed by an upsurge (24%) during the Gulf War period (1991) and a steady decline in the post-war period, 17% in 1992 and 14% in 1993. There was another wave of increased isolation rate (27%) during a period of relative calm in the country (1996) studied for comparison. The predominant Shigella species was S. flexneri which accounted for 46% of the 202 isolates, followed by S. sonnei (42%), S. dysenteriae (7%) and S. boydii (5%). Fifty-four percent of the 202 Shigella isolates were resistant to ampicillin, 56% to trimethoprim/sulfamethoxazole, 35% to chloramphenicol, 13% and 9% to cephalothin and amoxicillin/clavulanic acid respectively. All the isolates were fully susceptible to ciprofloxacin, the aminoglycosides and the second- and third-generation cephalosporins. Eighty-seven (43%) of the 202 isolates were resistant to two or more antibiotics. Of the 87 multiply resistant Shigella spp., 58 (67%) were S. flexneri while 19 (22%) were S. sonnei. Shigella resistance to the first-line antibiotics is a major problem that frequently limits the therapeutic options with orally available active antibiotic therapy.