A Study of the knowledge, attitudes and practices of community pharmacists to antibiotic resistance in Trinidad

•Antibiotic misuse accelerates the natural process of development of antibiotic resistance •The increasing antibiotic ineffectiveness is a threat to the practice of medicine, leading to an increase in morbidity and mortality as there are an estimated 750,000 deaths annually due to bacteria resistant sepsis •The presence of multi-dug resistant bacteria in North American and Europe has implications for the Caribbean •Education plays an important role in tackling antibiotic resistance •Although Caribbean physicians are aware of antibiotic resistance, this knowledge does not affect prescribing habits •Previous research among pharmacy students in Trinidad identified good knowledge, but the attitude towards use of antibiotics was poor •Research among pharmacists in Brazil identified causes of antibiotic resistance but the role of the law was not explored

Bacterial contamination of Leatherback Turtle (Dermochelys coriacea) eggs and sand in nesting chambers at Levera Beach, Grenada, West Indies - a preliminary study

The pilot study determines the potential role of bacterial contamination of egg surfaces at the time of oviposition and in the sand of the nesting chambers in lowering hatchability. A total of 15 species of bacteria were isolated from 20 eggs and 17 sand samples of egg nests, with little overlap in the species spectrum between eggs and sand. The most frequent bacteria found on the egg surface were Pseudomonas spp. followed by Citrobacter spp., Enterobacter cloacae and Morganella morganii, whereas from sand samples most frequent isolates were Bacillus spp. followed by Enterobacter spp. and Pseudomonas spp. All 15 isolated species are considered opportunistic pathogens, and could be potential causes for the reported lower hatchability. These pathogens also constitute a public health risk when eggs are consumed by humans. The majority of isolates showed antibiotic drug resistance, indicating environmental pollution.

Frequency and antimicrobial resistance of enteric bacteria with spoilage potential isolated from table eggs

The prevalence of potential spoilage microorganisms on the shells and in the egg contents of table eggs sold in Trinidad was determined. Table eggs samples were obtained from 23 poultry layer farms, 14 shopping malls and 102 supermarkets across the country. Each farm was visited twice approximately one month apart and 25 pooled eggs constituted a composite sample. Shopping malls were visited twice usually one month apart while supermarkets were visited once over a 4-month period. Swabs of egg shells and pooled yolk and albumen (egg content) were tested for selected bacteria using standard methods. The resistance of bacteria to seven antimicrobial agents was detected using the disc diffusion method. Of a total of 184 composite eggs (shells, yolk/albumen or both) sampled, 71 (38.6 per cent) samples were positive for enteric microbes, other than E. coli, Salmonella, Campylobacter spp. and Listeria spp. Enterobacter spp. and Klebsiella spp. were isolated from 15 (8.2 per cent) and 14 (7.6 per cent), respectively, of pooled egg shells alone and from 6 (3.3 per cent) and 3 (1.6 per cent), respectively, of egg content samples alone. Prevalence of enteric bacteria in egg contents was generally higher than found on egg shells with faeces/blood or cracks compared with those without, but the differences were not significant (P > 0.05; X2). The microbial load of egg content was not significantly affected by type of housing of laying birds, source of feeds, use of medicated feeds and temperatures at which eggs were kept at sale outlets. Of a total of 131 bacterial isolates tested, 125 (95.4 per cent) exhibited resistance to one or more antimicrobial agents and resistance was high to streptomycin (90.1 per cent), tetracycline (51.9 per cent) and kanamycin (30.5 per cent). Failure to properly handle or heat table eggs sold in Trinidad poses a potential health hazard to consumers because of their poor microbial quality and high frequency of resistance to antimicrobial agent.

Frequency and characteristics of selected enteropathogens in fecal and rectal specimens from childhood diarrhea in Trinidad, 1998-2000

Objective. To determine the prevalence and characteristics of selected enteric pathogens in diarrheic children in six counties of Trinidad. Methods. This cross-sectional study was conducted from April 1998 through March 2000, using standard methods, to detect Salmonella spp., Shigela spp., enteropathogenic Escherichia coli (EPEC), Campylobacter spp., Yersinia spp., Cryptosporidium parvum, and parasite ova. The antibiograms of the enteropathogens were determined using disk diffusion method.Results. A total of 236 samples; 86 samples originated directly from 17 health centers in two counties (St. George East and St. George West), while 150 samples were obtained from Trinidad Public Health Laboratory, having been submitted by private practitioners and personel from six counties in Trinidad. Of the 236 samples, 33 (14.0 percent) were positive for Shigella, 4 (1.7 percent) for Salmonella, and 1 (0.4 percent) was positive for hook worm ova. All the samples were negative for Cryptosporidium parvum and Yersinia spp. With the 86 samples collected directly from the health centers, in St. George East County the frequency of Shigella was 20.0 percent (12 of 60), compared with 26.9 percent (7 of 26) for samples from St. George West County, but the difference was not statistically significant (P> 0.05 with the chi-square test). For the 150 samples from the six counties that had been submitted directly to the Trinidad Public Health Laboratory, 14 of them (9.3 percent) were positive for Shigella, a figure statistically significantly lower than that found with the samples sampled directly from the health centers (P< 0.05 with the chi-square test). Sh. sonnei was the predominant serotype detected, accounting for 28 of the 33 Shigella isolates (84.8 percent) recovered from the 236 samples. Overall, the frequency of detection of enteropathogens had no seasonal pattern nor relationship to the county of origin. Of the 37 isolates of Salmonella and Shigella tested for antimicrobial sensitivity, all of them were sensitive to ciprofloxacin, gentamicin, and cefotaxime. In terms of resistance, 3 of the 37 isolates (8.1 percent) exhibited resistance to ampicillin, 1 (2.7 percent) to chloramphenicol, and 1 (2.7 percent) to sulfamethoxazole/ trimethoprim. Conclusions. Of the enteropathogens for which assays were done, Shigella sonnei was the most prevalent, and it has the highest probability of being an important etiological agent of childhood diarrhea in Trinidad (AU)

Bacteriuria in the elderly population in a developing country

Among 1470 elderly hospitalized and nonhospitalized people, 566 cases of bacteriuria were identified. There were 663 men (41.5% with bacteriuria) and 807 women (36.0% with bacteriuria). The overall prevalence of bacteriuria was 38.5%. More than 90% of the isolates were gram-negative organisms with Proteus species being the predominant pathogen among men, with 68.1% seen among inpatients. Escherichia coli was the main pathogen in women, with 62.0% recovered from inpatients. Catheterization was seen most commonly among non-hospitalized males with outflow obstruction. Catheter care in this population is often performed at home by these men who either refuse prostate surgery, are not fit for surgery, or are awaiting surgery. Polymicrobic bacteriuria was identified more frequently (approximately 60%) among the catheterized group. Of the 440 gram-negative bacilli recovered as single organisms, 352 (80.0%) were resistant to ampicillin, cephalothin, and tetracycline, whereas 229 (52.0%) were resistant to co-trimoxazole. The most effective antibiotics (in increasing order of sensitivity; 80% - 100%) were augmentin, nalidixic acid, cefuroxime, gentomicin, and ciprofloxacin. No mortality due to bacteremia complicated by bacteriuria was observed during the study period.

Non-antimicrobial properties of tetracyclines - dental and medical implications

The tetracyclines are a group of broad-spectrum antimicrobial agents. The first of these compounds, chlortetracycline was isolated from Streptomyces aureofaciens by Benjamin Duggar and introduced into the market in 1948. In 1952, tetracycline was derived semisynthetically from chlortetracycline by removal of its chlorine atom by catalytic hydrogenation. Methacycline, doxycycline and minocycline are all semi-synthetic derivatives. The tetracyclines are closely congeneric derivatives of polycyclic napthacenecarboxamide. The tetracyclines posses a wide range of antimicrobial activity against gram-positive and gram-negative bacteria. In vitro, these drugs are primarily bacteriostatic. Tetracycline have been used extensively as antimicrobial, chemically modified non-antimicrobial properties by Golub. The tetracyclines and their non-antimicrobial, chemically modified analogues have properties that appear to modulate host response by inhibiting the activity of the matrix metalloproteinases that cause collagen destruction. They also inhibit osteoclast function, stimulate osteoblastic bone formation, and regulate angiogenesis.(Au)

Prevalence of resistance to antimicrobials of Escherichia coli isolates from clinical sources at a private hospital in Trinidad

Antimicrobial susceptibility patterns of strains of Escherichia coli isolated between 1994 and 1998 were studied. Of the 1,283 strains examined, 75% were recovered from urine, 8.7% from wounds, 3.2% from blood, 2.6% from pus, and 10.5% from other sources. Isolates from inpatients and outpatients accounted for 46.1% and 53.9%, respectively. Gentamicin and nalidixic acid showed the greatest efficacy against isolates from both inpatients and outpatients, revealing a >90% sensitivity. Drugs with the lowest efficacies were ampicillin and amoxicillin-clavulanic acid, which showed a >45% resistance. Tetracycline showed a significant decline in resistance from 1994 to 1998 among strains from both inpatients and outpatients (P < 0.001). This decline may be related to a policy of restrictive antibiotic reporting by the Microbiology Laboratory and seminars for general practitioners, subsequent to an island-wide survey an antibiotic resistance. A similar pattern of declining resistance was also observed for cefuroxime. E. coli sensitivity to co-trimoxazole was relatively stable during the study period. Although the overall prevalence of resistance among E. coli strains is relatively low, on-going surveillance of bacterial resistance must continue. The microbial antibiogram can provide general practitioners and clinicians with data essential for optimum empiric choices. Further, the introduction of a policy of restrictive reporting may act "synergistically" with the education of doctors on resistance patterns, to effect island-wide reduction of antimicrobial resistance.

Facing antibiotic resistance

Antibiotic resistance reflects the natural selection pressure which favours those species, variants or strains resistant to antibiotic action. (AU)

Molecular analysis of Salmonella entriditis isolates from the Caribbean pulsed-field gel electrophoresis

Using pulsed-field electrophoresis (PFGE), between 1987 and 1996 we analyzed Salmonella enteriditis isolates from gastroenteritis cases in four Caribbean countries: Barbados, Saint Kitts and Nevis, Saint Lucia, and Trinidad and Tobago. We also determined the resistance of the isolates to 12 antimicrobial agents. Of the 129 isolates of S. enteritidis available for testing, DNA digested by XbaI revealed 13 distinctive PFGE patterns. The most prevalent XbaI PFGE patterns were group 1 (88 of 129 isolates, 68.2 percent) and group 2 (26 of 129, 20.2 percent). The patterns found among S. enteritidis isolates correlated with the geographical origin of the isolates. Of the 28 isolates from Barbados, 20 of them (71.4 percent) belonged to XbaI PFGE group 2, and of the 93 isolates from Trinidad and Tobago, 78 of them (83.9 percent) belonged to group 1. SpeI digestion of S. enteritidis genome was not as discriminatory as XbaI. Overall, of the 129 isolates, 67 of them (51.9 percent) exhibited resistance to one or more of the twelve antimicrobial agents that we tested. The prevalence of resistance was 53.8 percent for the S. enteritidis isolates tested from Trinidad and Tobago, 50.0 percent for those from Barbados, 28.6 percent for those from Saint Lucia, 100.0 percent for those from the island of Saint Kitts. Resistance was highest to triple sulfur (59 of 129, 7.8 percent), ampicillin (7 of 129, 5.4 percent), and carbamycin (5 of 129, 3.9 percent). (AU)

Prevalence of Bacterial Pathogens and Susceptibility Patterns from clinical sources in Trinidad

During a 12-month period (January-December, 1997), bacterial isolates of specimens from in-patients and out-patients of the Eric Wiliams Sciences Complex (EWMSC) were reviewed. A total of 3,513 specimens were processed, 43.1 percent from in-patients and 56.9 percent from out-patients. Of the 3,513 specimens, 1,129 (32.1 percent) yielded positive cultures. Micro-organisms from wounds, sputum and genital tract accounted for 90.2 percent, 51.5 percent and 31.8 percent, respectively, of all isolates. E coli (17.4 percent) and Enterococci (12.2percent) were the predominant isolates and were also the major pathogens from blood stream infections, 25.8 percent and 18.2 percent, respectively, followed by P aeruginosa, 15.2 percent. High levels of resistance were seen to ampicillin, augmentin (amoxicillin-clavulanic acid) and tetracycline. The most effective antibiotics were ceftazidime (no resistance in E coli Citrobacter spp, non-typhoidal Salmonella and Group B streptococci, 63.2 percent resistance in Acinetobacter spp, 15.2 percent in Enterobacter spp, 17.4 percent in Klebsiella spp.], erythromycin (no resistance in Enterobacter and Citrobacter spp, and 89.5 percent in Acinetobacter (spp), erythromycin (no resistance in Groups A and B streptococci, 85.1 percent in S aurens and S pneumoniae). The spectrum of isolates will provide clinicians with data on which to base their "best guess" aetiologic agent and choice of antibiotics when faced with infectious diseases in areas where laboratory assistance is not readily available.(Au)

Current use of antibiotics in opthalmology

The use of antibiotics in opthmalmology is based on the information from sensitivity studies derived from the ocular microbiology laboratory and results of clinical studies. Because of systemic use of antibiotics, bacteria develop mechanisms of resistance over time. The organisms considered pathogens evolve to become less frequent, and unusual organisms become the primary culprit. We have found an increasing trend of gram positive organisms such as Staphylococci and a decreasing incidence of gram negatives. As the same time, the antibiotic sensitivity profile has changed. The fluoroquinolones have been the antibiotic of choice for the last decade. Current laboratory data show a decreasing sensitivity profile. Clinical data are beginning to emerge that mirror this information. Data show that aminoglycosides, penicillins and other antibiotics such as vancomycin and chloramphenicol may be more appropriate. New antibiotics such as the oxazliodones and new generation quinolones may soon become the antibiotics of choice. (AU)

Retrospective and longitudinal study of salmonellosis in captive wildlife in Trinidad

Morbidity and mortality of captive wildlife at the Emperor Valley Zoo, Trinidad from 1993 to 1996 were analysed to determine involvement of Salmonella spp. A 6 mo longitudinal study was conducted to determine the frequency of isolation of Salmonella spp. from apparently healthy, sick and dead wild mammals, birds, and reptiles. The antibiograms of Salmonella isolates were determined using the disc diffusion method. Fecal samples randomly selected from animal enclosures and cloacal swabs of snakes were cultured for Salmonella spp. following enrichment in tetrathionate and selenite cystine broths. For the 1993-96 period, Salmonella spp. was implicated in 17 (12%) of 141 sick or dead animals and the predominant serotype was S. typhimurium. During the 6 mo prospective study in a mean animal population of 1,186, there were 20 (2%) and 14 (1%) animals that were sick and died respectively; Salmonella spp. was implicated in only one mortality. Overall, of 1,012 samples from apparently healthy wildlife cultured, 66 (7%) yielded 24 serotypes of Salmonella. The predominant serotype were S. seigburg (16 isolates), S. gaminara (6 isolates), and S. thompson (6 isolates). None of the samples yielded S. typhimurium. The frequency of isolation of Salmonella spp. in reptiles (14%) was significantly higher than found in either mammals (7%) or birds (3%). Sixty-five (99%) of 66 Salmonella spp. isolates exhibited resistance to one or more of the nine antimicrobial agents tested. Resistance was high to cephalothin (92%), moderate to streptomycin (35%) and tetracycline (29%), but significantly low to gentamicin (2%), chloramphenicol (0%), and sulphamethoxazole/trimethoprim (0%). The prevalence of asymptomatic infections by Salmonella spp. in zoo animals was high and the very high prevalence of antimicrobial resistance could be a problem when treating salmonellosis.

Antimicrobial resistance seen as an emergent problem by physicians in Trinidad - Poster abstract

OBJECTIVE: To understand the influences of antibiotic prescription practices of physicians in Trinidad on emergent bacterial resistance. DESIGN AND METHOD: A pre-tested questionnaire was self-administered to physicians to determine the factors influencing the choices and outcomes of antimicrobial prescribing. RESULTS: 56 physicians with a mean of 7.1 years experience participated in the survey. The most frequent prescriptions were for urogenital infections (50 percent), respiratory tract infections (48.2 percent) and skin and soft tissue infections (46.4 percent). Amoxil was the drug of choice for respiratory infections (42.1 percent), Flagyl and Septra (17.9 percent) each for genitourinary (GU) infections and doxycycline (41.4 percent) for STD's. Only 8.9 percent of physicians prescribed antibiotics for the common cold/flu. Patient's well-being was the priority in prescribing followed by emergent bacterial resistance. Approximately 76.7 percent of participants observed resistance in the community, especially to Amoxil (26.1 percent). Overprescribing (61.7 percent) was viewed as a major contributor to resistance. Physicians would like to depend on the laboratory to curtail resistance and want more educational programmes. CONCLUSIONS: This study identified the recognition of bacterial resistance as a physician concern and a need to study antibiotic use.(AU)

Antimicrobial resistance in the Caribbean - Poster abstract

OBJECTIVE: To determine the resistance patterns of organisms causing hospital and community acquired infections in the English-and Dutch-speaking Caribbean. METHOD: The data on antimicrobial resistance of gram negative bacteria isolated in six laboratories during the first 6 month period in 1998 and pathogens isolated from community infections in selectedcountries during 1994-1997 were reviewed. RESULTS: The overall resistance of gram negative aerobic bacilli (excluding salmonella spp and shigella spp)to ampicillin (range 51-85 percent), gentamicin (range 3-11 percent and trimethoprim-sulphamethoxazole (range 27 to 47 percent) did not significantly differ between the laboratories and countries. The resistance to third generation cephalosporins was 9 percent and 16 percent in two laboratories in Trinidad. Multiple antibiotic resistant S typhimurium PT 104b, S heidelberg, Sh flexnerii type 2/2a and low levels of ampicillin and gentamycin resistant S enteritidis strains causing community acquired enteric infections were observed in the Caribbean. The rates of penicillin resistant pneumococci (1 percent) and chloramphenicol resistant H. influenzae ( 3 percent) were low in the Caribbean. CONCLUSIONS: The potential for introduction and spread pf resistance genes in the Caribbean is very high. Hence, continuing surveillance of antimicrobial resistant pathogens in nosocomial and community is essential in the Caribbean. (AU)

Antimicrobial resistance in Helicobacter pylori in Barbados

OBJECTIVE: Helicobacter pylori eradication is essential in patients with peptic ulcer who are infected with the organism. The rate of eradication is related to the level of antimicrobial resistance to metronidazole, clarithromycin, amoxycillin and tetracycline in H pylori in this community. DESIGN AND METHODS: Gastric biopsies from all patients undergoing upper gastrointestinal endoscopy were cultured. Isolation was done on Thayer-Martin medium under microaerophilic conditions and isolates were sub-cultured on chocolate agar. MICs were determined using the E-test. RESULTS: 64 isolates were available for testing. Metronidazole resistance (MIC > 8mg/l) was observed in 39 percent (25/64), clarithromycin resistance (MIC > 2mg/l) in 4.7 percent (3/64), amoxycillin resistance (MIC > 8mg/l) in 4.7 percent (3/64) and tetracycline resistance (MIC > 4mg/l) in 3.1 percent (2/64). CONCLUSIONS: The high level of metronidazole resistance precludes the use of this antibiotic as first line therapy for H pylori in Barbados. It is recommended that a proton pump inhibitor, amoxycillin and clarithromycin be the combination of choice for eradication of H pylori in patients in Barbados.(Au)

Methicillin resistance among Trinidadian isolates of community and hospital strains of Staphylococcus aureus and their patterns of resistance to non-beta-lactam antibiotics

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in Trinidad and the extent of their resistance to other antimicrobial agents in hospital-acquired and community-acquired infections were evaluated over a 2-year period. A total of 450 S. aureus strains were isolated from different patients. The prevalence of methicillin resistance among S. aureus strains was 9.8% (44/450). The proportion of MRSA isolated from hospital sources and community sources was 12.5% (38/305) and 4.1% (6/145), respectively (P < 0.05). The resistant rates of MRSA to the non-beta-lactam antibiotics were as follows: 93.2% resistance to tetracycline, 68.2% to erythromycin, 61.4% to gentamicin, 45.5% to co-trimoxazole, and 20.5% to ciprofloxacin. No MRSA resistant to vancomycin was observed in this study. Study results showed significant increases in MRSA in hospital, 2% in 1995 to 12.5% in 1998 (P < 0.05), and community, 0% in 1995 to 4.1% in 1998 (P < 0.05). It has become apparent that infection control and surveillance initiatives must be focused now on the community in order to monitor and limit the spread of this new and expanding reservoir of MRSA.

Methicillin resistance among Trinidadian isolates of community and hospital strains of Staphylococcus aureus and their patterns of resistance to non-beta-lactam antibiotics

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in Trinidad and the extent of their resistance to other antimicrobial agents in hospital-acquired infections were evaluated over a 2-year period. A total of 450 S. aureus strains were isolated from different patients. The prevalence of methicillin resistance among S. aureus strains was 9.8 percent (44/450). The proportion of MRSA isolated from hospital sources and community sources was 12.5 percent (38/305) and 4.1 percent (6/145) respectively (P<0.05). The resistant rates of MRSA to the non-beta-lactam antibodies were as follows: 93.2 percent resistance to tetracycline, 68.2 percent to erythromycin, 61.4 percent to gentamicin, 45.5 percent to co-trimoxazole, and 20.5 percent to ciprofloxacin. No MRSA resistant to vancomycin was observed in this study. Study results showed significant increases in MRSA in hospital, 2 percent in 1995 to 12.5 percent in 1998 (P<0.05), and community, 0 percent in 1995 to 4.1 percent in 1998 (P<0.05). It has become apparent that infection must be focussed now on the community in order to monitor and limit the spread of this new and expanding reservoir of MRSA. (AU)

Methicillin resistant Staphylococcus aureus

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) at the General Hospital, Port-of-Spain, between June 1995 and May 1996 was determined. The MRSA prevalence rate was 4.6 percent of all S aureus isolates, with all but one nosocomially acquired. 15 isolates were associated with infections, and three were colonizing strains. 17 of the 18 patients with MRSA had received antibiotics previously, including 13 who had received multiple antibiotics. Skin and soft tissue were the sites of infection and colonization in 12 cases; and surgical wards and the Intensive Care Unit (ICU) accounted for 16 MRSA isolates. All isolates were sensitive to vancomycin and all but one were resistant to gentamicin. MRSA occurred sporadically in a wide distribution of wards and physicians' services, although the isolation of three strains from the ICU and three strains from a surgical ward were temporally related. Only one of two deaths was attributable to MRSA. Control of the spread of MRSA in this hospital must include the reinforcement of the appropriate use of antibiotics, hand washing and appropriate isolation of patients in the surgical and intensive care wards.(Au)