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Extended-spectrum beta-lactamases in clinical isolates of Klebsiella pneumoniae from Zagreb, Croatia.

Forty clinical isolates of Klebsiella pneumoniae, from various clinical specimens, with reduced susceptibility to ceftazidime, were tested for extended-spectrum beta-lactamase (ESBL) production. ESBL production was demonstrated by an 8-fold reduction in the minimum inhibitory concentration (MIC) of ceftazidime combined with clavulanate (2 mg/L) compared to ceftazidime alone in all strains. The aim of this investigation was the biochemical and molecular characterization of the ESBL produced by K. pneumoniae strains and their Escherichia coli transconjugants. Transfer of ceftazidime resistance was demonstrated in 23 of 40 strains. Thirteen strains produced an ESBL with the isoelectric point of 8.2 which was encoded by a self-transferable multiresistance plasmid of 150 kb. The substrate profile was similar to that of the SHV-5 isolated initially in Chile. Seven of these 12 strains had an additional TEM beta-lactamase. Six isolates and their transconjugants produced a plasmid-encoded ESBL with an isoelectric point close to 5.4. The remaining 21 strains produced an ESBL with an isoelectric point of 7.6 (thus probably SHV-2) which was encoded on a plasmid transferable to E. coli in 4 strains only. Four of those strains possessed an additional plasmid encoded TEM beta-lactamase with an isoelectric point close to 5.4. The transconjugants harbored a multiresistance plasmid of 150 kb. Thus SHV-2 and SHV-5 enzymes appear to have been the most common ESBLs in K. pneumoniae from Zagreb during 1994-1995.

Anti-Bacterial Agents↗

Extended-spectrum beta-lactamase-producing Enterobacteriaceae in an Italian intensive care unit: clinical and therapeutical remarks.

In this study we evaluated the prevalence of Enterobacteriaceae and the epidemiology of ESBL+ microorganisms in an ICU of our Institution over a 5-year period and analyzed the clinical features and outcomes of the infections caused by these microorganisms. The most frequent ESBL+ isolate was Proteus mirabilis (69 isolates, 58%); a high rate of positive results in the double-disk synergy test (DDS) was also recognized for Klebsiella pneumoniae (52 isolates, 51%), whereas this phenomenon was observed less frequently in other species. In 312 cases the isolated microorganism was considered to be the cause of infection; we documented 103 wound infections, 89 UTIs, 62 LRTIs, 30 primary bacteremias, 27 infections of indwelling catheters and 1 CNS infection. The overall mortality rate due to ESBL+ strains was 1%, compared with 10.6% rate caused by ESBL-negative Enterobacteriaceae. This could be explained because ESBL+ strains caused mostly localized infections (wound infections and UTIs), whereas systemic or severe infections were sustained by ESBL-negative strains, and therapy with carbapenems was started promptly after ESBL+ isolation (always within 24h after strain isolation).

Anti-Bacterial Agents↗

Extended-spectrum beta-lactamase-producing Klebsiella spp.

Extended-spectrum beta-lactamases (ESBLs) are associated particularly with Klebsiella spp. These enzymes have arisen by mutation of the genes coding for clavulanate-sensitive, plasmid-mediated beta-lactamases such as TEM-1, TEM-2 and SHV-1. Amino acid changes in ESBLs confer enhanced hydrolysis of oxyimino-aminothiazolyl beta-lactams and aztreonam. Enzyme hyperproduction and loss of porins contribute to hydrolytic efficiency. ESBLs are highly susceptible to inhibition by clavulanate, and their presence can be detected by the disc-approximation test, using amoxycillin/clavulanate and an ESBL-susceptible antibiotic. Other manual procedures have been used and commercial tests to detect the enzymes include Etest, Vitek and Dade Microscan products. The epidemiology of ESBLs is complex, and epidemic and sporadic strains may be encountered in the same hospital. Spread between hospitals--even countries--has been documented. ESBL activity is carried on large plasmids that often carry determinants for resistance to aminoglycosides and other antibiotics, and this is transmissible to Escherichia coli and other species of Enterobacteriaceae in which ESBLs have been detected.

Humans↗

Prevalence of extended spectrum beta lactamase producing gram negative bacteria in a tertiary care hospital.

BACKGROUND & OBJECTIVES: Extended spectrum beta lactamase (ESBL) producing Gram negative bacteria are increasingly being associated with hospital infections thereby rendering all beta lactams, except carbapenems ineffective in the treatment of infections related to these organisms. A knowledge about their prevalence is essential to guide the appropriate antibiotic treatment of severe infections in hospitalized patients. The present work was carried out to study the prevalence of ESBL producing Gram negative bacteria in a tertiary care hospital. METHODS: A total of 678 Gram negative bacteria were included in the study. They were isolated from various clinical samples obtained from indoor patients admitted to the All India Institute of Medical Sciences, New Delhi during March to June 2001. These isolates were screened for ESBL production by the inhibitor based test recommended by the National Committee for Clinical Laboratory Standards (NCCLS) using Klebsiella pneumoniae ATCC 700603 as positive control and Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 as negative controls. RESULTS: Out of the 678 strains tested, 458 (68%) were found to be ESBL producers. Among the bacterial species, ESBL production was most common in Klebsiella spp. (80%). The proportion of ESBL positive isolates was highest from intensive care units (79%), followed by Medical Oncology (75%), Medical (54%) and Surgical wards (50%). INTERPRETATION & CONCLUSION: A high prevalence of ESBL positive isolates was found in our hospital. This has important implications as carbapenems remain the only choice of treatment for infections caused by these organisms. The control measures include judicious use of antibiotics and implementation of appropriate infection control measures to control the spread of these strains in the hospital.

Cross Infection↗

[Extended-spectrum beta-lactamase detection in Enterobacteriaceae and antibiotic susceptibility analysis].

OBJECTIVE: To detect the extended-spectrum beta-lactamases (ESBLs) in family Enterobacteriaceae and analyze the antibiotic susceptibility of those ESBLs-producing strains. METHODS: ESBLs were determined by the double-disk confirmatory test and 8 antibiotic susceptibilities were tested with the disk disffusion method in those strains producing ESBLs. RESULTS: Forty-seven ESBLs-producing strains comprised of 25 of E. coli, 14 of K. pneumoniae, 5 of E. cloacae, 1 of K. oxytoca, 1 of K. rhinoscleromatis, and 1 of S. liquefaciens. The susceptibility rates of those strains were: 100% for imipenem and meropenem, 89.4% for piperacillin/tazobactam, 72.4% for cefoxitin and 65.9% for cefotetan. CONCLUSION: E. coli and K. pneumoniae are the prime strains producing ESBLs in Enterobacteriaceae. Imipenem and meropenem are the best drugs to deal with those ESBLs-producing strains. Piperacillin/tazobactam is better than cephamycins and other beta-lactama/beta-lactamase inhibitor combination.

Anti-Bacterial Agents↗

Prevalence of extended-spectrum beta-lactamases produced by nosocomial isolates of Enterobacteriaceae in Trakya University Hospital, Turkey.

The prevalence of extended-spectrum beta-lactamase (ESBL) production by 194 nosocomial isolates of Enterobacteriacea recovered from 1995 to 1999 was investigated. The ESBL production was determined by the double-disk synergy test and was confirmed by the E-test ESBL strip. Twenty-three isolates (21 Klebsiella pneumoniae, one Escherichia coli, one Providencia rettgeri) were found as ESBL-producers (11.8%). These isolates were also usually resistant to non-betalactam antibiotics. Most of them contained a beta-lactamase with a pI of 7.6. All the strains conjugally transferred their ESBLs to recipient E. coli. Contrary to others, ESBL-producing K. pneumoniae strains isolated in 1999 were resistant to ciprofloxacin, and had the identical plasmid profiles suggestive of an outbreak. Ciprofloxacin resistance in these strains could not be transferred. In conclusion, K. pneumoniae was the main ESBL-producing species among nosocomial isolates of Enterobacteriacae in our hospital.

Conjugation, Genetic↗

Comparison of double disc and combined disc method for the detection of extended spectrum beta lactamases in enterobacteriaceae.

OBJECTIVE: To compare double disc approximation and combined disc method for their ability to detect extended spectrum b lactamase (ESBL) production in enterobacteriaceae and determine the percentage of isolates which are falsely reported as sensitive in absence of ESBL detection, in a clinical microbiology laboratory of a tertiary care hospital between September-October 2002. METHODS: Selected isolates were identified according to standard biochemical tests. Disc susceptibility tests were performed according to NCCLS. ESBL detection by combined disc [cefotaxime (30 ug) versus cefotaxime plus clavulanate (30+10 ug)] was compared with detection using double discs [amoxy-clavulanic acid (20+10 ug) and aztreonam (30 ug) applied 10 mm apart]. Results were interpreted according to NCCLS and analysed on SPSS version 10. RESULTS: ESBL production was detected in 140 (30%) isolates by combined disc method and 139 (29.5%) by double disc method. There was no significant difference between two methods. Of the ESBL positive isolates 41 (29%) gave zone diameters that were within the sensitivity range cutoff and would have been falsely reported as being beta lactam sensitive in absence of ESBL detection. CONCLUSION: ESBL detection should be routinely performed in clinical laboratories as false reporting would result in treatment failure despite in vitro sensitivity. No difference was found between the combined disc and double disc methods hence either of two could be used.

Enterobacteriaceae↗

[Studies on the nucleotides sequences of extended-spectrum-beta-lactamases encoding genes of Escherichia coli and Klebsiella pneumoniae and the related molecular evolution].

OBJECTIVE: To identify TEM-type and SHV-type ESBLs encoding genes of ESBLs-producing Klebsiella pneumoniae and Escherichia coli isolated from clinical species in West China Hospital of Sichuan University and study the molecular evolution of the ESBLs. METHODS: The nucleotide sequences of TEM-type and SHV-type ESBLs encoding genes amplified by PCR were detected by automatic sequencer, and the subtypes of the encoding genes were determined by Blastx searching. The molecular evolution of ESBLs was studied by means of bioinformatics. RESULTS: In this study, the subtypes of ESBLs were SHV-2 and TEM-19, the distribution of silent mutation in ten bla(SHV-2) was identical, and that of two bla(TEM-19) was the same; the distribution of silent mutation of bla(TEM-19) was the same as that of bla(TEM-1). The distribution of silent mutation of bla(SHV-2) observed here was different from that observed in other countries. CONCLUSION: SHV-2 was the main ESBLs in this study. The bla(SHV-2) and bla(TEM-19) in this study originated from the same transferable variants respectively. The prevalent SHV-2 in different countries resulted from convergent evolution. It seems possible that the bla(TEM-19) identified by this study might originate directly from the transferable bla(TEM-1) identified in this study.

DNA, Bacterial↗

[Plasmid-mediated cephalosporinase among extended-spectrum-beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae].

OBJECTIVE: To investigate the prevalence and genotype of plasmid-mediated cephalosporinase (AmpC) beta-lactamase in extended-spectrum-beta-lactamase-producing (ESBL) Escherichia coli and Klebsiella pneumoniae. METHODS: 24 strains of cefoxitin-resistant ESBL-producing E. coli and 8 strains of K. pneumoniae were collected from January to December 2001 at Beijing Chaoyang Hospital. Analytical isoelectric focusing electrophoresis was used to measure the pI of the beta-lactamase. Conjugation experiment was used to study the transfer of cefoxitin resistance. The homology of the isolates was determined by pulsed field gel electrophoresis (PFGE). Plasmid-mediated AmpC enzyme genes were amplified and sequenced by using multiplex PCR. RESULTS: The prevalence of ESBL-producing E. coli and K. pneumoniae were 16.8% (49/292) and 16.5% (35/212), respectively. The prevalence of AmpC enzyme among ESBL-producing E. coli and K. pneumoniae isolates were 2.0% (1/49) and 17.1% (6/35), respectively. These 7 isolates produced DHA-1 AmpC enzyme. One strain of K. pneumoniae could transfer cefoxitin resistance to the recipient. Among 7strains, 5 strains produced CTX-M-3 and 2 produced SHV-12 ESBL. These 7 strains also produced TEM-1 broad-spectrum enzymes. These strains harbored 2 - 5 plasmids and one of them were 33 - 36 kb. PFGE showed these strains came from a variety of clones. CONCLUSIONS: In this hospital, 7 strains of the ESBL-positive E. coli and K. pneumoniae produced both DHA-1AmpC enzyme and CTX-M-3/SHV-12 ESBL. These 7 strains were from different clones.

Anti-Bacterial Agents↗

Prevalence of clinical strains resistant to various beta-lactams in a tertiary care hospital in India.

The incidence of infection due to extended spectrum beta-lactamases (ESBLs) producing Enterobacteriaceae has markedly increased in recent years. The traditional susceptibility methods lack sensitivity and/or specificity and this issue has prompted the search for an accurate test to detect the presence of ESBL. The present study included 300 bacterial strains and was undertaken to determine the prevalence of ESBL-producing strains. Here, compared three tests: a double disk synergy test (DDS), a three-dimensional test (3-D), and an inhibitor potentiated disk diffusion test (IPT); each test employed three different antibiotic discs, i.e., ceftazidime, ceftriaxone, and cefotaxime, in order to screen for ESBL strains. A strain was said to be an ESBL producer if it showed positive result(s) on any one of the three tests. The prevalence rate of ESBL in our hospital was 12.6% (38/300). IPT detected the most strains (34/38), followed by 3-D (23/38), and then DDS (15/38). The ceftriaxone disc was found to detect more ESBLs than either the ceftazidime or the cefotaxime disc.

Anti-Bacterial Agents↗

[Identification and expression of blaCTX-M-14 and blaCTX-M-24].

OBJECTIVE: To identify the ESBL gene and the prevalence in Escherichia coli and Klebsiella pneumoniae strain isolated from Huashan Hospital, Shanghai. METHODS: Isolates were confirmed as an ESBL producing strain by double-disk synergy test and NCCLS Confirmatory Test. Antibiotic susceptibilities were determined by standard agar dilution procedure on Mueller-Hinton agar. To determine whether the resistance was transferable, the conjugation experiment was performed; plasmids were isolated from clinical isolates and transcojugants. The partial bla(gene) of ESBL producing isolates and their transcojugants were detected by PCR using universal primers for TEM, SHV, CTX-M-1group, Toho-1group, CTX-M-13group respectively. The entire bla(CTX-M-13) group were amplified by PCR using the primers outside the Open Reading Frame (ORF) of CTX-M-13group beta-lactamases; the PCR products of entire bla(CTX-M-13)group were cloned into vector and the recombinant plasmids were transformed into the recipient strain for expression; the PCR products were also directly sequenced and analyzed; the clinical isolates of ESBL producers were detected by PFGE. RESULTS: ESBL producers were resistant to most beta-lactams and non-beta-lactams. Most transconjugants were obtained at frequency of 10(-4) approximately 10(-5) and resistance to non-beta-lactams was cotransferred with the ESBL activity to the transconjugant. A plasmid of about > 23.1 kb was obtained from each tansconjugant by plasmid extraction. Partial gene amplification products of CTX-M-13 group gene were obtained from isolates and their transconjugants. The bla(CTX-M-13)group from 4 transconjugants were identified as bla(CTX-M-14), and other six were bla(CTX-M-24); those ESBLs were mediated by plasmids (> 23.1 kb); the transformants producing CTX-M-14 or CTX-M-24 were resistant to most beta-lactams, which were much more resistant to cefotaxime than to ceftazidine; PFGE patterns of those isolates were different. CONCLUSION: clinical isolate of Escherichia coli and Klebsiella pneumoniae isolated from Huashan Hospital, Shanhai produced CTX-M-14 or CTX-M-24, which caused the isolate resistant to most beta-lactams; no clone spread in those isolates was found.

Anti-Bacterial Agents↗

Occurrence of extended-spectrum beta-lactamase in clinical isolates of Klebsiella pneumoniae in a University Hospital, Thailand.

The occurrence and antimicrobial susceptibility of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae in patients attending Siriraj Hospital in Bangkok from August 2000 to January 2001 were determined. ESBL-producing isolates were screened with four different methods: disk diffusion according to the National Committee for Clinical Laboratory Standards (NCCLS) guidelines, Etest ESBL (CT/CTL and TZ/TZL), Oxoid combination discs and MIC Etest strip. Antimicrobial susceptibility testing were determined by a microdilution automatic method (VITEX system, bioMerieux). Of 22,178 clinical specimens, 400 (1.8%) K. pneumoniae were isolated Of 26% (104/400) of these isolates were suspected to be ESBL-producing. Rates of detection of ESBL-producing K. pneumoniae were 18.67%, 30% and 23.78% for blood, sputum and urine samples, respectively. Susceptibility testing has revealed that all 70 tested isolates including 53 isolates from blood and sputum and 17 isolates from urine samples were susceptible to imipenem (MIC< or =4 mg/L). None of the tested isolates were susceptible to cephalosporins, cephamycin and aztreonam. Rate of susceptibility to ciprofloxacin, levofloxacin, gentamicin and tobramycin were 60%, 64%, 28% and 9%, respectively, for isolates from blood and sputum; 71%, 71%, 18% and 6% for urinary isolates. The present findings revealed a high occurrence rate of multi-drug resistance ESBL-producing K. pneumoniae in patients attending the university hospital. Imipenem was highly active against ESBL-producing K. pneumoniae.

Anti-Bacterial Agents↗

Antibacterial susceptibility of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae and Escherichia coli.

BACKGROUND: The prevalence of extended-spectrum beta-lactamase-producing organisms and their antimicrobial resistance patterns may vary between geographic areas. OBJECTIVES: To evaluate the prevalence and susceptibility of ESBL-producing organisms among Klebsiella pneumoniae and Escherichia coli isolated from adult and pediatric patients in two Israeli hospitals. METHODS: ESBL production was tested according to recommendations of the Clinical and Laboratory Standards Institute, using ceftazidime (30 microg) and a combination of ceftazidime/clavulanate (30/ 10 microg) disks with a > or =5 mm difference indicating positivity. Antibiotic susceptibilities were determined by the disk diffusion method according to CLSI standards. Minimal inhibitory concentrations were determined by the E-test. RESULTS: The prevalence of ESBL-producing organisms was significantly higher among K. pneumoniae than E. coli isolates - 32% (241/765) vs. 10% (57/547) respectively (P < 0.001), and more frequently isolated from adults than children (odds ratio 2.27 for K. pneumoniae and 12.94 for E. coli). Resistance rates for amoxicillin/ clavulanate, piperacillin-tazobactam, amikacin, and ciprofloxacin among the ESBL-producing K. pneumoniae and E. coli isolates were 95%, 82%, 49% and 77% for K. pneumoniae, and 77%, 35%, 25% and 100% for E coli. Two (0.8%) ESBL-producing and 4 (0.7%) ESBL-negative K. pneumoniae isolates showed intermediate susceptibility (MIC 6 microg/ml) to meropenem. All isolates were sensitive to ertapenem and colistin. CONCLUSION: ESBL production among K. pneumoniae and E. coli is more prevalent in the adult population than the pediatric population and is associated with multidrug resistance.

Adult↗

Prevalence and antimicrobial resistance of extended-spectrum beta-lactamases-producing Escherichia coli and Klebsiella pneumoniae strains isolated in a university hospital in Split, Croatia.

The prevalence of Escherichia coli and Klebsiella pneumoniae that produce extended-spectrum b-lactamases (ESBL) was investigated in patients of a university hospital in Split, Croatia. Patients were grouped according to age (pediatric vs. adult), antibiotic type, and hospital ward. From Jan. 2001 to Dec. 2002, the susceptibility of E. coli and K. pneumoniae isolates to antimicrobials was tested. ESBL production was assayed using the double-disk synergy test. ESBL-producing E. coli and K. pneumoniae were detected in all sites of infection sampled. The percentages of ESBL-positive isolates were higher in the pediatric wards than in the adult wards. The antibiotics most commonly prescribed to patients in all hospital wards belonged to the third-generation cephalosporin group. Among ESBL producers, E. coli isolates were more resistant to aminoglycosides, but less resistant to ciprofloxacin and cotrimoxazole. Resistance of E. coli and K. pneumoniae to ciprofloxacin was exclusively found in isolates from adult patients. None of the isolates, regardless of ESBL production, was resistant to carbapenemes. In addition, the prevalence and antimicrobial resistance of ESBL-producing E. coli and K. pneumoniae isolates differed between pediatric and adult patients.

Adult↗

[Extended-spectrum beta-lactamases: their role in clinical microbiology laboratory, treatment and infection control].

The major mechanism responsible for resistance to beta-lactam antibiotics is the production of beta-lactamases. These enzymes, which have the ability to inactivate extended-spectrum beta-lactam antibiotics, like cefotaxime and ceftazidime are called as extended-spectrum beta-lactamases (ESBL). The most important pathogen which produces beta-lactamases among Gram positive bacteria is Staphylococcus aureus and the members of the Enterobacteriaceae family are the leading beta-lactamase producing organisms among Gram negative bacteria. Although the beta-lactamase inhibitors like clavulanic acid, sulbactam and tazobactam could block ESBL effects, ESBL's have still been considered as a threat since they are coded by plasmids and can easily be transmitted between species. Recently, more than 150 ESBLs have been identified. Numerous methods have been proposed for the detection of ESBLs in clinical isolates. Imipenem seems to be the most effective agent for the therapy and control of the spread of infections caused by ESBL-producing bacteria. In this review article, the roles of ESBL in clinical microbiology laboratory, treatment and infection control, have been discussed.

Anti-Bacterial Agents↗

An outbreak of SHV-5 producing Klebsiella pneumoniae in a neonatal intensive care unit; meropenem failed to avoid fecal colonization.

An outbreak of extended-spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae (ESBL-Kp) in a neonatal intensive care unit prompted a prospective surveillance study between 12th September and 6th October 2003. Surveillance was carried out by obtaining stool samples twice a week. The DNA relatedness of the isolates was shown by random amplified polymorphic DNA comparison (ERIC-PCR). ESBL production was identified by clavulanate synergy, isoelectric focusing, PCR and sequence analysis. During the study period, 49 neonates were hospitalized in the neonatal intensive care unit (NICU). In the first 20-day period, five neonates were infected with ESBL-Kp. The first patient treated with third generation cephalosporin and the second patient treated with meropenem died. While all three infected survivors were clinically improving, the digestive tracts were being colonized by SHV-5 producing Klebsiella. In the next period of the study, five neonates were colonized by ESBL-Kp as well. Univariate comparison of risk factors between colonized and non-colonized neonates was not significant. A total of 24 colonally related ESBL-Kp have been recovered from clinical materials and stool samples. This study demonstrated that parenterally applied meropenem, though successful in treating the systemic illness, might fail to protect the digestive tract from colonization of ESBL-Kp.

Anti-Bacterial Agents↗

Frequency and sensitivity pattern of Extended Spectrum beta Lactamase producing isolates in a tertiary care hospital laboratory of Pakistan.

OBJECTIVE: To determine frequency, distribution and sensitivity pattern of Extended-Spectrum beta Lactamase (EBSL) producing organism at a tertiary care hospital in Pakistan. METHODS: All members of enterobacteriacae isolated between April and August 2002 were studied. Isolates were speciated according to standard biochemical tests. Susceptibility testing was performed by Kirby-Bauer method. ESBL was detected using double disc method using cefotaxime versus cefotaxime plus clavulanate according to NCCLS. Statistical analysis was performed by SPSS version 10. Test of significance were calculated using chi-square test. RESULTS: During the study period, 1137/2840 (40%) of the isolates tested were found to be ESBL producing. ESBL positivity was detected in 50% Enterobacter sp., 41% E. coli and 36% K. pneumoniae. ESBL production was noted in 52% of nosocomial isolates tested (415/799). ESBL was more frequent in patients at the extremes of ages (under 5 years and more than 60 years). Cross-resistance to non-beta lactam antibiotics (flouoroquinolones, aminoglycosides and co-trimoxazole) was also more frequent in ESBL producing organisms (p<0.05). CONCLUSION: A high frequency of ESBL positivity amongst our isolates is documented which is alarming in low-income settings where expensive second line agents are unavailable. Our data supports urgent need for regular screening and surveillance for these organisms.

Adolescent↗

Clinical sources and prevalence of resistance to antimicrobials of Klebsiella pneumoniae strains in Trinidad.

OBJECTIVE: To assess the frequency of Klebsiella pneumoniae (K. pneumoniae) recovery from clinical specimens from hospital and community patients, their antibiotic profile, the extent of extended-spectrum beta lactamase (ESBL) production among such isolates, and the impact on patient management. METHODS: The study recovered 1,118 K. pneumoniae strains from various clinical specimens from hospital and community patients, from 1995 to 2004, at the Eric Williams Medical Sciences Complex. All 1,118 isolates underwent testing for multi-antibiotic resistance, of which 480 that fulfilled the criteria for possible ESBL production underwent further examination, according to guideline recommendations of the National Committee for Clinical Laboratory Standards. RESULTS: From 68,537 specimens processed, 62.9% were from hospital patients and 37.1% from community patients. Approximately 21% of the specimens yielded positive bacterial cultures from which, 1,118 were K. pneumoniae strains. Ciprofloxacin, imipenem, aztreonam, nalidixic acid and gentamicin showed the greatest efficacy (>95% sensitivity) against isolates from both hospital and community sources. Tetracycline and ampicillin showed almost 100% resistances. The other antibiotics displayed varying degrees of resistance. The prevalence of ESBL production was approximately 8.5% and most ESBL producers (51.2%) were from urine, followed by wounds (22.0%), blood (19.5%), and lower respiratory tract specimens (4.9%). Five K. pneumoniae isolates were resistant to the carbapenem, and imipenem. CONCLUSION: The study isolated K. pneumoniae from 8% of patients. All K. pneumoniae isolates were resistant to more than 2 antibiotics. The prevalence of ESBL production was 8.5%. Five (12.2%) strains of ESBL producers were resistant to imipenem. Continued infection control measures and prudent use of antibiotic agents are essential in reducing the spread of multi-resistant ESBL producing K. pneumoniae.

Anti-Bacterial Agents↗